LISTA DE ARTÍCULOS, CITAS EN MEDLINE, RESÚMENES DE ALGUNOS TRABAJOS PUBLICADOS EN MEDLINE

1: Bruce N, Perez-Padilla R, Albalak R. Indoor air pollution in developing countries: a major environmental and public health challenge. Bull World Health Organ. 2000;78(9):1078-92. Review.

2: Carrillo-Rodriguez JG, Sansores RH, Castrejon A, Perez-Padilla R, Ramirez-Venegas A, Selman M. [Hypersensitivity pneumonitis in Mexico City]. Salud Publica Mex. 2000 May-Jun;42(3):201-7. Spanish.

3: Perez Padilla JR, Vazquez Garcia JC. [Estimation of gasometric values at different altitudes above sea level in Mexico]. Rev Invest Clin. 2000 Mar-Apr;52(2):148-55. Spanish.

4: Perez-Padilla R, Vazquez-Garcia JC, Meza-Vargas S. [The surgical risk in sleep apnea: the implications for tonsillectomies]. Gac Med Mex. 1999 Sep-Oct;135(5):501-6. Review. Spanish.

5: Perez-Padilla JR. [Ketotifen (Zaditen and K-Asthmal): a drug with sales disproportionate to its demonstrated effectiveness]. Gac Med Mex. 1999 Mar-Apr;135(2):165-70. Review. Spanish.

6: Perez-Padilla JR, Regalado-Pineda J, Moran-Mendoza AO. [The domestic inhalation of the smoke from firewood and of other biological materials. A risk for the development of respiratory diseases]. Gac Med Mex. 1999 Jan-Feb;135(1):19-29. Spanish.

7: Vazquez-Garcia JC, Arellano-Vega SL, Regalado-Pineda J, Perez-Padilla JR. [Normal ventilatory response to hypoxia and hypercapnia at an altitude of 2240 meters]. Rev Invest Clin. 1998 Jul-Aug;50(4):323-9. Spanish.

8: Volkow P, Perez-Padilla R, del-Rio C, Mohar A. The role of commercial plasmapheresis banks on the AIDS epidemic in Mexico. Rev Invest Clin. 1998 May-Jun;50(3):221-6.

9: Ramirez-Venegas A, Sansores RH, Perez-Padilla R, Carrillo G, Selman M. Utility of a provocation test for diagnosis of chronic pigeon Breeder's disease. Am J Respir Crit Care Med. 1998 Sep;158(3):862-9.

10: Selman M, Perez-Padilla R, Pardo A. Problems encountered in high-level research in developing countries. Chest. 1998 Aug;114(2):610-3. Review. No abstract available.

11: Perez Padilla R. [More on the medicine-industry relationship]. Rev Invest Clin. 1997 Jul-Aug;49(4):343. Spanish. No abstract available.

12: Romieu I, Meneses F, Ramirez M, Ruiz S, Perez Padilla R, Sienra JJ, Gerber M, Grievink L, Dekker R, Walda I, Brunekreef B. Antioxidant supplementation and respiratory functions among workers exposed to high levels of ozone. Am J Respir Crit Care Med. 1998 Jul;158(1):226-32.

13: Chi-Lem G, Perez-Padilla R. Gas exchange at rest during simulated altitude in patients with chronic lung disease. Arch Med Res. 1998 Spring;29(1):57-62.

14: Perez-Padilla R, Regalado J, Vedal S, Pare P, Chapela R, Sansores R, Selman M. Exposure to biomass smoke and chronic airway disease in Mexican women. A case-control study. Am J Respir Crit Care Med. 1996 Sep;154(3 Pt 1):701-6.

15: Perez-Padilla R, Gaxiola M, Salas J, Mejia M, Ramos C, Selman M. Bronchiolitis in chronic pigeon breeder's disease. Morphologic evidence of a spectrum of small airway lesions in hypersensitivity pneumonitis induced by avian antigens. Chest. 1996 Aug;110(2):371-7.

16: Sansores RH, Ramirez-Venegas A, Perez-Padilla R, Montano M, Ramos C, Becerril C, Gaxiola M, Pare P, Selman M. Correlation between pulmonary fibrosis and the lung pressure-volume curve. Lung. 1996;174(5):315-23.

17: Perez-Padilla R, Gaxiola M, Salas J, Sansores R, Chapela R, Carrillo G, Selman M. [Capability of clinical and laboratory findings to predict the grade of fibrosis and the diagnosis in diffuse interstitial lung diseases]. Rev Invest Clin. 1995 Mar-Apr;47(2):95-101. Spanish.

18: Perez-Padilla R. [The uncertain future of Mexican medical journals]. Rev Invest Clin. 1995 Mar-Apr;47(2):165-7. Spanish. No abstract available.

19: Perez Padilla R, Volkow Fernandez P. [Mexican physicians succeed with a live plant tissue graft in animals: this opens new therapeutic possibilities]. Gac Med Mex. 1994 May-Jun;130(3):176-7. Spanish. No abstract available.

20: Selman-Lama M, Perez-Padilla R. Airflow obstruction and airway lesions in hypersensitivity pneumonitis. Clin Chest Med. 1993 Dec;14(4):699-714. Review.

21: Perez-Padilla R, Salas J, Chapela R, Sanchez M, Carrillo G, Perez R, Sansores R, Gaxiola M, Selman M. Mortality in Mexican patients with chronic pigeon breeder's lung compared with those with usual interstitial pneumonia. Am Rev Respir Dis. 1993 Jul;148(1):49-53.

22: Perez-Padilla JR, Slawinski E, Difrancesco LM, Feige RR, Remmers JE, Whitelaw WA. Characteristics of the snoring noise in patients with and without occlusive sleep apnea. Am Rev Respir Dis. 1993 Mar;147(3):635-44.

23: Perez Martinez SO, Perez-Padilla JR. [Gasometric values reported in healthy subjects from the Mexican population: review and analysis]. Rev Invest Clin. 1992 Jul-Sep;44(3):353-62. Spanish.

24: Perez-Padilla R, Salas J, Carrillo G, Selman M, Chapela R. Prevalence of high hematocrits in patients with interstitial lung disease in Mexico City. Chest. 1992 Jun;101(6):1691-3.

25: Sansores R, Perez-Padilla R, Pare PD, Selman M. Exponential analysis of the lung pressure-volume curve in patients with chronic pigeon-breeder's lung. Chest. 1992 May;101(5):1352-6.

26: Sandoval J, Cicero R, Seoane M, Perez-Padilla R, Quesada A, Lupi-Herrera E. Behavior of the pulmonary circulation at rest and during exercise in miliary tuberculosis. Chest. 1991 Jan;99(1):152-4.

27: Viniegra L, Jimenez JL, Perez-Padilla JR. [The challenge of evaluating clinical competence]. Rev Invest Clin. 1991 Jan-Mar;43(1):87-98. Spanish.

28: Perez-Padilla JR, Ponce de Leon-Rosales S. [Ethical attitudes related to problems of managing patients with acquired immunodeficiency syndrome].
Salud Publica Mex. 1990 Jan-Feb;32(1):3-14. Spanish.

29: Hatridge J, Haji A, Perez-Padilla JR, Remmers JE. Rapid shallow breathing caused by pulmonary vascular congestion in cats. J Appl Physiol. 1989 Dec;67(6):2257-64.

30: Perez-Padilla JR, Viniegra Velazquez L. [Method for calculating the distribution of randomly expected scores in a false-true-do not know-type of test]. Rev Invest Clin. 1989 Oct-Dec;41(4):375-9. Spanish.

31: Perez-Padilla R, Cervantes D, Chapela R, Selman M. Rating of breathlessness at rest during acute asthma: correlation with spirometry and usefulness of breath-holding time. Rev Invest Clin. 1989 Jul-Sep;41(3):209-13.

32: Zamora Mucino A, Gomez Jaume A, Gorodezky M, Perez Padilla R, Amigo MC, Barrios R. [Cardiovascular abnormalities in Ehlers-Danlos syndrome. Report of a case]. Arch Inst Cardiol Mex. 1989 May-Jun;59(3):301-7. Spanish.

33: Perez-Padilla JR, Molina Tellez E, Barragan Garcia R. [Obstructive sleep apnea syndrome associated with nasal, velo-pharyngeal and tracheal stenosis. Surgical management of a case including uvulo-palato-pharyngoplasty]. Rev Invest Clin. 1988 Apr-Jun;40(2):171-5. Spanish. No abstract available.

34: Martinez W, Sandoval J, Perez-Padilla R, Maxwell R, Seoane M, Lupi-Herrera E. PaO2 increases with coughing in patients with chronic lung disease. Lung. 1988;166(5):287-91.

35: Perez-Padilla JR, West P, Kryger M. Snoring in normal young adults: prevalence in sleep stages and associated changes in oxygen saturation, heart rate, and breathing pattern. Sleep. 1987 Jun;10(3):249-53.

36: Perez-Padilla R, Conway W, Roth T, Anthonisen N, George C, Kryger M. Hypercapnia and sleep O2 desaturation in chronic obstructive pulmonary disease. Sleep. 1987 Jun;10(3):216-23.

37: Light RB, Perez-Padilla R, Kryger MH. Perfluorochemical artificial blood as a volume expander in hypoxemic respiratory failure in dogs. Chest. 1987 Mar;91(3):444-9.

38: Perez-Padilla JR, Bracamonte-Peraza R, Manrique G, Ruiz-Primo ME. [Accuracy of an the ear oximeter Biox-III and its sensitivity to carboxyhemoglobin in Mexico City]. Arch Inst Cardiol Mex. 1986 Jul-Aug;56(4):303-7. Spanish.

39: Perez Padilla JR, Lupi Herrera E. [Respiratory problems during sleep]. Arch Inst Cardiol Mex. 1986 Jan-Feb;56(1):1-3. Spanish. No abstract available.

40: Perez-Padilla R, West P, Lertzman M, Kryger MH. Breathing during sleep in patients with interstitial lung disease. Am Rev Respir Dis. 1985 Aug;132(2):224-9.

41: Perez Padilla JR. [Clinical implications of snoring]. Rev Invest Clin. 1984 Apr-Jun;36(2):155-65. Spanish. No abstract available.

42: Perez-Padilla R, Sifuentes-Osornio J, Sada-Diaz E, Guerrero FJ, Nunez-Rasilla V, Diaz-Jouanen E. [Extrapulmonary manifestations and rapidly fatal course in 3 patients with desquamative pneumonitis]. Rev Invest Clin. 1984 Jan-Mar;36(1):39-43. Spanish. No abstract available.

43: Brownell LG, Perez-Padilla R, West P, Kryger MH. The role of protriptyline in obstructive sleep apnea. Bull Eur Physiopathol Respir. 1983 Nov-Dec;19(6):621-4.

44: Perez-Padilla R, West P, Kryger MH. Sighs during sleep in adult humans. Sleep. 1983;6(3):234-43.

45: Perez Padilla JR. [Rehydration therapy without insulin in severe hyperglycemia. Report of one case]. Rev Invest Clin. 1981 Jan-Mar;33(1):49-51. Spanish. No abstract available.

46: de Lascurain RE, Perez Padilla JR. [Fever of unknown origin. A report of 55 cases seen at the National Institute of Nutrition from 1971 to 1977]. Rev Invest Clin. 1980 Apr-Jun;32(2):243-54. Spanish. No abstract available.

Citas en MEDLINE:

1: Perez-Padilla JR, Regalado-Pineda J, Vazquez-Garcia JC.
Reproducibilidad de espirometrías en trabajadores mexicanos y valores de referencia internacionales. Salud Publica Mex. 2001 Mar-Apr;43(2):113-21. Spanish.
PMID: 11381840 [PubMed - in process]

2: Perez-Padilla R, Perez-Guzman C, Baez-Saldana R, Torres-Cruz A.
Cooking with biomass stoves and tuberculosis: a case control study.
Int J Tuberc Lung Dis. 2001 May;5(5):441-7.
PMID: 11336275 [PubMed - in process]

3: Perez-Padilla R.
[Tuberculosis in Mexico, an old public health debt].
Gac Med Mex. 2001 Jan-Feb;137(1):93-4. Spanish. No abstract available.
PMID: 11244837 [PubMed - indexed for MEDLINE]

4: Bruce N, Perez-Padilla R, Albalak R.
Indoor air pollution in developing countries: a major environmental and public health challenge.
Bull World Health Organ. 2000;78(9):1078-92. Review.
PMID: 11019457 [PubMed - indexed for MEDLINE]

5: Carrillo-Rodriguez JG, Sansores RH, Castrejon A, Perez-Padilla R, Ramirez-Venegas A,
Selman M.
[Hypersensitivity pneumonitis in Mexico City].
Salud Publica Mex. 2000 May-Jun;42(3):201-7. Spanish.
PMID: 10929501 [PubMed - indexed for MEDLINE]

6: Perez Padilla JR, Vazquez Garcia JC.
[Estimation of gasometric values at different altitudes above sea level in Mexico].
Rev Invest Clin. 2000 Mar-Apr;52(2):148-55. Spanish.
PMID: 10846438 [PubMed - indexed for MEDLINE]

7: Perez-Padilla R, Vazquez-Garcia JC, Meza-Vargas S.
[The surgical risk in sleep apnea: the implications for tonsillectomies].
Gac Med Mex. 1999 Sep-Oct;135(5):501-6. Review. Spanish.
PMID: 10596490 [PubMed - indexed for MEDLINE]

8: Perez-Padilla JR.
[Ketotifen (Zaditen and K-Asthmal): a drug with sales disproportionate to its demonstrated
effectiveness].
Gac Med Mex. 1999 Mar-Apr;135(2):165-70. Review. Spanish.
PMID: 10327750 [PubMed - indexed for MEDLINE]

9: Perez-Padilla JR, Regalado-Pineda J, Moran-Mendoza AO.
[The domestic inhalation of the smoke from firewood and of other biological materials. A risk for
the development of respiratory diseases].
Gac Med Mex. 1999 Jan-Feb;135(1):19-29. Spanish.
PMID: 10204309 [PubMed - indexed for MEDLINE]

10: Vazquez-Garcia JC, Arellano-Vega SL, Regalado-Pineda J, Perez-Padilla JR.
[Normal ventilatory response to hypoxia and hypercapnia at an altitude of 2240 meters].
Rev Invest Clin. 1998 Jul-Aug;50(4):323-9. Spanish.
PMID: 9830321 [PubMed - indexed for MEDLINE]

11: Volkow P, Perez-Padilla R, del-Rio C, Mohar A.
The role of commercial plasmapheresis banks on the AIDS epidemic in Mexico.
Rev Invest Clin. 1998 May-Jun;50(3):221-6.
PMID: 9763887 [PubMed - indexed for MEDLINE]

12: Ramirez-Venegas A, Sansores RH, Perez-Padilla R, Carrillo G, Selman M.
Utility of a provocation test for diagnosis of chronic pigeon Breeder's disease.
Am J Respir Crit Care Med. 1998 Sep;158(3):862-9.
PMID: 9731018 [PubMed - indexed for MEDLINE]

13: Selman M, Perez-Padilla R, Pardo A.
Problems encountered in high-level research in developing countries.
Chest. 1998 Aug;114(2):610-3. Review. No abstract available.
PMID: 9726752 [PubMed - indexed for MEDLINE]

14: Perez Padilla R.
[More on the medicine-industry relationship].
Rev Invest Clin. 1997 Jul-Aug;49(4):343. Spanish. No abstract available.
PMID: 9708002 [PubMed - indexed for MEDLINE]

15: Romieu I, Meneses F, Ramirez M, Ruiz S, Perez Padilla R, Sienra JJ, Gerber M, Grievink L,
Dekker R, Walda I, Brunekreef B.
Antioxidant supplementation and respiratory functions among workers exposed to high levels of ozone.
Am J Respir Crit Care Med. 1998 Jul;158(1):226-32.
PMID: 9655734 [PubMed - indexed for MEDLINE]

16: Chi-Lem G, Perez-Padilla R.
Gas exchange at rest during simulated altitude in patients with chronic lung disease.
Arch Med Res. 1998 Spring;29(1):57-62.
PMID: 9556924 [PubMed - indexed for MEDLINE]

17: Perez-Padilla R, Regalado J, Vedal S, Pare P, Chapela R, Sansores R, Selman M.
Exposure to biomass smoke and chronic airway disease in Mexican women. A case-control
study.
Am J Respir Crit Care Med. 1996 Sep;154(3 Pt 1):701-6.
PMID: 8810608 [PubMed - indexed for MEDLINE]

18: Perez-Padilla R, Gaxiola M, Salas J, Mejia M, Ramos C, Selman M.
Bronchiolitis in chronic pigeon breeder's disease. Morphologic evidence of a spectrum of small
airway lesions in hypersensitivity pneumonitis induced by avian antigens.
Chest. 1996 Aug;110(2):371-7.
PMID: 8697836 [PubMed - indexed for MEDLINE]

19: Sansores RH, Ramirez-Venegas A, Perez-Padilla R, Montano M, Ramos C, Becerril C,
Gaxiola M, Pare P, Selman M.
Correlation between pulmonary fibrosis and the lung pressure-volume curve.
Lung. 1996;174(5):315-23.
PMID: 8843057 [PubMed - indexed for MEDLINE]

20: Perez-Padilla R, Gaxiola M, Salas J, Sansores R, Chapela R, Carrillo G, Selman M.
[Capability of clinical and laboratory findings to predict the grade of fibrosis and the diagnosis in
diffuse interstitial lung diseases].
Rev Invest Clin. 1995 Mar-Apr;47(2):95-101. Spanish.
PMID: 7610289 [PubMed - indexed for MEDLINE]

21: Perez-Padilla R.
[The uncertain future of Mexican medical journals].
Rev Invest Clin. 1995 Mar-Apr;47(2):165-7. Spanish. No abstract available.
PMID: 7610287 [PubMed - indexed for MEDLINE]

22: Perez Padilla R, Volkow Fernandez P.
[Mexican physicians succeed with a live plant tissue graft in animals: this opens new therapeutic
possibilities].
Gac Med Mex. 1994 May-Jun;130(3):176-7. Spanish. No abstract available.
PMID: 7657084 [PubMed - indexed for MEDLINE]

23: Selman-Lama M, Perez-Padilla R.
Airflow obstruction and airway lesions in hypersensitivity pneumonitis.
Clin Chest Med. 1993 Dec;14(4):699-714. Review.
PMID: 8313674 [PubMed - indexed for MEDLINE]

24: Perez-Padilla R, Salas J, Chapela R, Sanchez M, Carrillo G, Perez R, Sansores R, Gaxiola M,
Selman M.
Mortality in Mexican patients with chronic pigeon breeder's lung compared with those with usual
interstitial pneumonia.
Am Rev Respir Dis. 1993 Jul;148(1):49-53.
PMID: 8317813 [PubMed - indexed for MEDLINE]

25: Perez-Padilla JR, Slawinski E, Difrancesco LM, Feige RR, Remmers JE, Whitelaw WA.
Characteristics of the snoring noise in patients with and without occlusive sleep apnea.
Am Rev Respir Dis. 1993 Mar;147(3):635-44.
PMID: 8442599 [PubMed - indexed for MEDLINE]

26: Perez Martinez SO, Perez-Padilla JR.
[Gasometric values reported in healthy subjects from the Mexican population: review and
analysis].
Rev Invest Clin. 1992 Jul-Sep;44(3):353-62. Spanish.
PMID: 1488580 [PubMed - indexed for MEDLINE]

27: Perez-Padilla R, Salas J, Carrillo G, Selman M, Chapela R.
Prevalence of high hematocrits in patients with interstitial lung disease in Mexico City.
Chest. 1992 Jun;101(6):1691-3.
PMID: 1600793 [PubMed - indexed for MEDLINE]

28: Sansores R, Perez-Padilla R, Pare PD, Selman M.
Exponential analysis of the lung pressure-volume curve in patients with chronic pigeon-breeder's
lung.
Chest. 1992 May;101(5):1352-6.
PMID: 1582296 [PubMed - indexed for MEDLINE]

29: Sandoval J, Cicero R, Seoane M, Perez-Padilla R, Quesada A, Lupi-Herrera E.
Behavior of the pulmonary circulation at rest and during exercise in miliary tuberculosis.
Chest. 1991 Jan;99(1):152-4.
PMID: 1984947 [PubMed - indexed for MEDLINE]

30: Viniegra L, Jimenez JL, Perez-Padilla JR.
[The challenge of evaluating clinical competence].
Rev Invest Clin. 1991 Jan-Mar;43(1):87-98. Spanish.
PMID: 1866504 [PubMed - indexed for MEDLINE]

31: Perez-Padilla JR, Ponce de Leon-Rosales S.
[Ethical attitudes related to problems of managing patients with acquired immunodeficiency
syndrome].
Salud Publica Mex. 1990 Jan-Feb;32(1):3-14. Spanish.
PMID: 2330511 [PubMed - indexed for MEDLINE]

32: Hatridge J, Haji A, Perez-Padilla JR, Remmers JE.
Rapid shallow breathing caused by pulmonary vascular congestion in cats.
J Appl Physiol. 1989 Dec;67(6):2257-64.
PMID: 2606831 [PubMed - indexed for MEDLINE]

33: Perez-Padilla JR, Viniegra Velazquez L.
[Method for calculating the distribution of randomly expected scores in a false-true-do not
know-type of test].
Rev Invest Clin. 1989 Oct-Dec;41(4):375-9. Spanish.
PMID: 2631171 [PubMed - indexed for MEDLINE]

34: Perez-Padilla R, Cervantes D, Chapela R, Selman M.
Rating of breathlessness at rest during acute asthma: correlation with spirometry and usefulness of
breath-holding time.
Rev Invest Clin. 1989 Jul-Sep;41(3):209-13.
PMID: 2813994 [PubMed - indexed for MEDLINE]

35: Zamora Mucino A, Gomez Jaume A, Gorodezky M, Perez Padilla R, Amigo MC, Barrios R.
[Cardiovascular abnormalities in Ehlers-Danlos syndrome. Report of a case].
Arch Inst Cardiol Mex. 1989 May-Jun;59(3):301-7. Spanish.
PMID: 2782994 [PubMed - indexed for MEDLINE]

36: Perez-Padilla JR, Molina Tellez E, Barragan Garcia R.
[Obstructive sleep apnea syndrome associated with nasal, velo-pharyngeal and tracheal stenosis.
Surgical management of a case including uvulo-palato-pharyngoplasty].
Rev Invest Clin. 1988 Apr-Jun;40(2):171-5. Spanish. No abstract available.
PMID: 3175371 [PubMed - indexed for MEDLINE]

37: Martinez W, Sandoval J, Perez-Padilla R, Maxwell R, Seoane M, Lupi-Herrera E.
PaO2 increases with coughing in patients with chronic lung disease.
Lung. 1988;166(5):287-91.
PMID: 3146675 [PubMed - indexed for MEDLINE]

38: Perez-Padilla JR, West P, Kryger M.
Snoring in normal young adults: prevalence in sleep stages and associated changes in oxygen
saturation, heart rate, and breathing pattern.
Sleep. 1987 Jun;10(3):249-53.
PMID: 3629087 [PubMed - indexed for MEDLINE]

39: Perez-Padilla R, Conway W, Roth T, Anthonisen N, George C, Kryger M.
Hypercapnia and sleep O2 desaturation in chronic obstructive pulmonary disease.
Sleep. 1987 Jun;10(3):216-23.
PMID: 3629083 [PubMed - indexed for MEDLINE]

40: Light RB, Perez-Padilla R, Kryger MH.
Perfluorochemical artificial blood as a volume expander in hypoxemic respiratory failure in dogs.
Chest. 1987 Mar;91(3):444-9.
PMID: 3816321 [PubMed - indexed for MEDLINE]

41: Perez-Padilla JR, Bracamonte-Peraza R, Manrique G, Ruiz-Primo ME.
[Accuracy of an the ear oximeter Biox-III and its sensitivity to carboxyhemoglobin in Mexico
City].
Arch Inst Cardiol Mex. 1986 Jul-Aug;56(4):303-7. Spanish.
PMID: 2945522 [PubMed - indexed for MEDLINE]

42: Perez Padilla JR, Lupi Herrera E.
[Respiratory problems during sleep].
Arch Inst Cardiol Mex. 1986 Jan-Feb;56(1):1-3. Spanish. No abstract available.
PMID: 2943239 [PubMed - indexed for MEDLINE]

43: Perez-Padilla R, West P, Lertzman M, Kryger MH.
Breathing during sleep in patients with interstitial lung disease.
Am Rev Respir Dis. 1985 Aug;132(2):224-9.
PMID: 2411177 [PubMed - indexed for MEDLINE]

44: Perez Padilla JR.
[Clinical implications of snoring].
Rev Invest Clin. 1984 Apr-Jun;36(2):155-65. Spanish. No abstract available.
PMID: 6484335 [PubMed - indexed for MEDLINE]

45: Perez-Padilla R, Sifuentes-Osornio J, Sada-Diaz E, Guerrero FJ, Nunez-Rasilla V,
Diaz-Jouanen E.
[Extrapulmonary manifestations and rapidly fatal course in 3 patients with desquamative
pneumonitis].
Rev Invest Clin. 1984 Jan-Mar;36(1):39-43. Spanish. No abstract available.
PMID: 6718828 [PubMed - indexed for MEDLINE]

46: Brownell LG, Perez-Padilla R, West P, Kryger MH.
The role of protriptyline in obstructive sleep apnea.
Bull Eur Physiopathol Respir. 1983 Nov-Dec;19(6):621-4.
PMID: 6360257 [PubMed - indexed for MEDLINE]

47: Perez-Padilla R, West P, Kryger MH.
Sighs during sleep in adult humans.
Sleep. 1983;6(3):234-43.
PMID: 6622880 [PubMed - indexed for MEDLINE]

48: Perez Padilla JR.
[Rehydration therapy without insulin in severe hyperglycemia. Report of one case (author's
transl)].
Rev Invest Clin. 1981 Jan-Mar;33(1):49-51. Spanish. No abstract available.
PMID: 7268230 [PubMed - indexed for MEDLINE]

49: de Lascurain RE, Perez Padilla JR.
[Fever of unknown origin. A report of 55 cases seen at the National Institute of Nutrition from
1971 to 1977].
Rev Invest Clin. 1980 Apr-Jun;32(2):243-54. Spanish. No abstract available.
PMID: 7423082 [PubMed - indexed for MEDLINE]

Resúmenes (Abstracts). de algunos artículos ya mencionados.

Salud Publica Mex 2001 Mar-Apr;43(2):113-21
Perez-Padilla JR, Regalado-Pineda J, Vazquez-Garcia JC.
Instituto Nacional de Enfermedades Respiratorias, Departamento de Fisiologia Respiratoria,
Calzada de Tlalpan 4502, 14080 Mexico, D.F., Mexico. perezpad@servidor.unam.mx

OBJECTIVE: To describe spirometric function and adjustment to foreign prediction equations in
Mexican workers claiming work related disability. MATERIAL AND METHODS: We
reviewed 5771 spirometries done at the Mexican National Institute of Respiratory Diseases
performed with equipment and methods proposed by the American Thoracic Society. With the
spirometries we generated multiple regression equations separated for men and women based on
age and height, compared to other in common use reported by Knudson and Hankinson in North
America and by Quanjer in europeans. RESULTS: 80% of the tests were reproducible for FVC
and FEV1 according to ATS, whereas 10% were reproducible for neither. Mean FVC in men
was 12% above values reported by Quanjer, 22% above Knudson, 3% above Hankinson and
6% above Rodriguez-Reynaga, whereas similar values for women were 18%, 10%, 0% and 1%.
Excluding obese and those who had less than 2 acceptable maneuvers, the numbers increase by
1-2%. FEV1 was also above predicted. CONCLUSIONS: Most workers requesting disability
are able to generate a reproducible spirometry. However for the same gender, age and height,
workers had a FEV1 and a FVC above normal values reported by Knudson and Quanjer and
are more similar to those reported by Hankinson in Mexican-Americans. While a set of
appropriate reference values are obtained, regression equations obtained from the studied group
will generate less error in the evaluation of disability in mexican workers. The English version of
this paper is available at: http://www.insp.mx/salud/index.html.

PMID: 11381840 [PubMed - in process]

Am J Respir Crit Care Med 1998 Sep;158(3):862-9
Utility of a provocation test for diagnosis of chronic pigeon Breeder's
disease.
Ramirez-Venegas A, Sansores RH, Perez-Padilla R, Carrillo G, Selman M.
Instituto Nacional de Enfermedades Respiratorias, Mexico DF, Mexico.

Chronic hypersensitivity pneumonitis (CHP) can be difficult to differentiate from other interstitial
lung diseases (ILD). To determine the diagnostic usefulness of a provocation test (PT), 17
patients with CHP induced by avian antigens, 17 with other ILD, and five healthy control subjects
were challenged with pigeon serum. After PT, an increase in body temperature (BT) and a
decrease in FVC, PaO2 and SaO2% were observed in all patients with CHP and in three with
ILD. No reaction was noticed in healthy subjects. ROC curves showed that for FVC the best cut
point was a drop of 16% displaying sensitivity (S): 76%, specificity (SP): 81%, positive
predictive value (PPV): 81%, and negative predictive value (NPV): 83%. For a drop of 3 mm
Hg in PaO2 or 3% SaO2, S was 88% for both, SP was 82 and 86%, PPV was 81 and 82%,
and NPV was 82 and 86%, respectively. An increase of BT > 0.5(o) C showed S, 100%; SP,
82%; PPV, 100%; NPV, 86%. A univariate regression analysis confirmed that changes in BT
and FVC are predicting values of CHP: RR, 82.5 (CI, 10.43 to 651.76) and 1.21 (CI, 1.06 to
1.36). There were no challenge test complications. These findings suggest that PT is a useful tool
for diagnosis of CHP.

PMID: 9731018 [PubMed - indexed for MEDLINE]

Int J Tuberc Lung Dis 2001 May;5(5):441-7
Cooking with biomass stoves and tuberculosis: a case control study.
Perez-Padilla R, Perez-Guzman C, Baez-Saldana R, Torres-Cruz A.

National Institute of Respiratory Diseases, Tlalpan, Mexico City, Mexico.
perezpad@servidor.unam.mx

OBJECTIVE: To search for an association between tuberculosis and use of biomass stoves
found recently in a cross sectional study. DESIGN: In a case-control study based in a chest
referral hospital, the cases were 288 patients with active smear-positive or culture-positive
tuberculosis, and the controls were 545 patients with ear nose and throat ailments with no
evidence of chest disease studied at the same time as the cases. Exposure to present or previous
biomass smoke by history of cooking with traditional wood stoves was assessed by positive or
negative response. RESULTS: Exposure to biomass smoke was significantly higher in cases than
in controls. Crude odds ratios for tuberculosis and biomass smoke exposure were 5.2 (95%CI
3.1-8.9) for current exposure, 3.4 (95%CI 2.4-5.0) for past or present exposure and 1.8
(95%CI 1.1-3.0) for past exposure. The association was observed only for patients living in
Metropolitan Mexico City and urban or suburban areas in the center of Mexico providing most
cases and controls. For rural areas, the power of the study was low and the origin of the patients
heterogeneous. Odds ratio for Mexico City Metropolitan area and the center of Mexico was 2.4
(95%CI 1.04-5.6), adjusted for age, sex, level of education, crowding, smoking,
socio-economic level, zone of residence and state of birth. In the same model smoking had an
OR of 1.5 (95%CI 1.0-2.3) for tuberculosis. CONCLUSION: Our results support a causal role
of current domestic biomass smoke exposure in tuberculosis.
PMID: 11336275 [PubMed - in process]

Gac Med Mex 2001 Jan-Feb;137(1):93-4
[Tuberculosis in Mexico, an old public health debt]. [Article in Spanish]
Perez-Padilla R.

Instituto Nacional de Enfermedades Respiratorias, Tlalpan 4502 Mexico DF, 14080.
perezpad@servidor.unam.mx

PMID: 11244837 [PubMed - indexed for MEDLINE]

Salud Publica Mex 2000 May-Jun;42(3):201-7
[Hypersensitivity pneumonitis in Mexico City]. [Article in Spanish]
Carrillo-Rodriguez JG, Sansores RH, Castrejon A, Perez-Padilla R, Ramirez-Venegas
A, Selman M.

Clinica de Enfermedades Intersticiales del Pulmon, Instituto Nacional de Enfermedades
Respiratorias (INER), Mexico. josecr@data.net.mx

OBJECTIVE: To investigate the association between the urban area of origin of patients and the
prevalence of hypersensitivity pneumonitis (HP), induced by avian antigens. MATERIAL AND
METHODS: A case-control study was conducted in 1999 at the National Institute of
Respiratory Diseases (NIRD). Cases were 109 consecutive HP patients and controls were 184
patients: 39 with idiopathic pulmonary fibrosis (IPF), 63 with pulmonary tuberculosis (PTB), and
82 with asthma. Mexico City and surrounding counties (SC) were divided into 5 geographical
areas: 1) Downtown; 2) North-East (NE); 3) South-East (SE); 4) North-West (NW) and 5)
South-West (SW). Statistical analysis consisted of calculation of disease prevalence by urban
area; associations were assessed with odds ratios and 95% confidence intervals. Multivariate
analysis with multiple logistic regression was performed to adjust for age, gender and
socioeconomic level. RESULTS: Eighty HP cases were located in the NE southernmost and SE
northernmost areas of Mexico City (48 and 32, respectively) (OR = 3.86; 95% CI 2.17-6.96).
Thirty-six controls with asthma came from the SW area, (where NIRD is located) (p < 0.05),
and four from SC. Controls with PTB and IPF were scattered throughout the study area.
CONCLUSIONS: The NE southernmost and SE northernmost areas were associated with HP.
The cause of HP may not be geographical; a garbage dump used to be located in this area,
suggesting that exposure to organic particles might contribute to the development of HP in
susceptible individuals.

PMID: 10929501 [PubMed - indexed for MEDLINE]

Gac Med Mex 1999 Sep-Oct;135(5):501-6
[The surgical risk in sleep apnea: the implications for tonsillectomies].
[Article in Spanish]
Perez-Padilla R, Vazquez-Garcia JC, Meza-Vargas S.
Departamento de Fisiologia Respiratoria, Laboratorio de Sueno, Instituto Nacional de
Enfermedades Respiratorias, Tlalpan, Mexico DF. perezpad@servidor.unam.mx

Hypertrophy of tonsils or adenoids is the commonest cause of obstructive sleep apnea (OSA) in
children. Adenotonsillectomy (AT) is frequently curative in children with OSA but riskier than the
same procedure without OSA. It is crucial to identify OSA among the patients programmed for
AT because they require a detailed evaluation, frequently including total or limited
polysomnogram. Patients with OSA need a continuous surveillance before, during, and after
surgery, ideally in a referral hospital.
PMID: 10596490 [PubMed - indexed for MEDLINE]

Am. J. Respir. Crit. Care Med., Vol 154, No. 3, 09 1996, 701-706.
Exposure to biomass smoke and chronic airway disease in Mexican women. A case-control study
R Perez-Padilla, J Regalado, S Vedal, P Pare, R Chapela, R Sansores and M Selman
National Institute of Pulmonary Diseases, Mexico City, DF, Mexico.

A case-control study was performed in women older than 40 yr of age to evaluate the risk of cooking
with traditional wood stoves for chronic bronchitis and chronic airway obstruction (CAO). The subjects were recruited from patients attending
a referral chest hospital in Mexico City. We selected 127 patients with chronic bronchitis or CAO, of which 63 had chronic bronchitis alone, 23
had CAO alone (FEV1 less than 75% of predicted), and 41 had both chronic bronchitis and CAO (cases). Four control groups were selected: 83
patients with pulmonary tuberculosis, 100 patients with interstitial lung diseases, 97 patients with ear, nose and throat ailments, and 95 healthy
visitors to the hospital (controls). Exposure to wood smoke, assessed as any or none, and as hour-years (years of exposure multiplied by
average hours of exposure per day) was significantly higher in cases than in controls. Crude odds ratios for wood smoke exposure were 3.9
(95% CI, 2.0 to 7.6) for chronic bronchitis only, 9.7 (95% CI, 3.7 to 27) for CAO plus chronic bronchitis, and 1.8 (95% CI, 0.7 to 4.7) for CAO only.
Differences in exposure to wood smoke persisted after adjusting by stratification and logistic regression for age, income, education, smoking,
place of residence, and place of birth. Risk of chronic bronchitis alone and chronic bronchitis with CAO increased linearly with hour-years of
cooking with a wood stove; odds ratios for exposure to more than 200 hour-years compared with nonexposed were 15.0 (95% CI, 5.6 to 40) for
chronic bronchitis only and 75 (95% CI, 18 to 306) for chronic bronchitis with CAO. The findings support a causal role of domestic wood smoke
exposure in chronic bronchitis and chronic airflow obstruction.

This article has been cited by other articles:

Albalak, R, Frisancho, A R, Keeler, G J (1999). Domestic biomass fuel combustion and chronic bronchitis in two rural Bolivian villages.
Thorax 54: 1004-1008 [Abstract] [Full Text]
Smith, K. R. (2000). Inaugural Article: National burden of disease in India from indoor air pollution. Proc. Natl. Acad. Sci. U. S. A. 97:
13286-13293 [Abstract] [Full Text]
PAUWELS, R. A., BUIST, A. S., CALVERLEY, P. M. A., JENKINS, C. R., HURD, S. S. (2001). Global Strategy for the Diagnosis,
Management, and Prevention of Chronic Obstructive Pulmonary Disease . NHLBI/WHO Global Initiative for Chronic Obstructive Lung
Disease (GOLD) Workshop Summary. Am J Respir Crit Care Med 163: 1256-1276 [Full Text]

Rev Invest Clin 2000 Mar-Apr;52(2):148-55
[Estimation of gasometric values at different altitudes above sea level in Mexico].
[Article in Spanish]
Perez Padilla JR, Vazquez Garcia JC.
Instituto Nacional de Enfermedades Respiratorias. perezpad@servidor.unam.mx

We calculated reference values for arterial blood gases at different altitudes in Mexico assuming
that sea level PaCO2 is 40 Torr, and in Mexico City (2.24 km. above the sea level) is 31.13
Torr, average of reported reference values. With the previous two points, it is possible to
calculate a linear regression: PaCO2 = 40-3.96(altitude in km.). The equation is very similar to
that calculated from reports in alveolar gas in North-Americans (Fitzgerald < 5 km): PACO2 =
39.3-3.11(altitude in km), and from subjects acclimatized to acute altitude exposure (< 5 km):
PACO2 = 38.3-2.5 (altitude in km). It is also similar to a alinear equation that can be calculated
assuming that hyperventilation in permanent habitants of moderate altitudes is inversely
proportional to inspired molar concentration of O2: PaCO2 = PIO2/3.74. On the other hand, the
equation is very different than that obtained from Andean natives (Hurtado): PaCO2 =
40.4-1.35(altitude in km). The proposed linear equation for Mexico gives very similar results (<
2 Torr difference) than a complex curvilinear equation by Morris et al. appropriate only up to 2.3
km. Evidence from acute exposure to altitude (acclimatized) and in North-Americans (alveolar
gas) supports a reasonably accurate linear relationship up to 4 km. and also that the increase in
ventilation in response to moderate altitudes in adult permanent residents is inversely proportional
to molar concentration of O2. PAO2 was calculated with alveolar gas equation and resting the
P(A-a)O2 we obtained PaO2. In conclusion, according to reference values in Mexico City,
PaCO2 decreases about 4 Torr per km of altitude above the sea level. The decrease is similar to
that reported in North-Americans and in acute exposure to altitude (acclimatized), but much less
than that reported in native Peruvians. Ventilation is inversely proportional to the molar
concentration of O2 at least up to an altitude where SaO2 is at or above 90%.

PMID: 10846438 [PubMed - indexed for MEDLINE]

Bull World Health Organ 2000;78(9):1078-92
Indoor air pollution in developing countries: a major environmental and public health challenge.
Bruce N, Perez-Padilla R, Albalak R.
Department of Public Health, University of Liverpool, England. ngb@liv.ac.uk

Around 50% of people, almost all in developing countries, rely on coal and biomass in the form
of wood, dung and crop residues for domestic energy. These materials are typically burnt in
simple stoves with very incomplete combustion. Consequently, women and young children are
exposed to high levels of indoor air pollution every day. There is consistent evidence that indoor
air pollution increases the risk of chronic obstructive pulmonary disease and of acute respiratory
infections in childhood, the most important cause of death among children under 5 years of age in
developing countries. Evidence also exists of associations with low birth weight, increased infant
and perinatal mortality, pulmonary tuberculosis, nasopharyngeal and laryngeal cancer, cataract,
and, specifically in respect of the use of coal, with lung cancer. Conflicting evidence exists with
regard to asthma. All studies are observational and very few have measured exposure directly,
while a substantial proportion have not dealt with confounding. As a result, risk estimates are
poorly quantified and may be biased. Exposure to indoor air pollution may be responsible for
nearly 2 million excess deaths in developing countries and for some 4% of the global burden of
disease. Indoor air pollution is a major global public health threat requiring greatly increased
efforts in the areas of research and policy-making. Research on its health effects should be
strengthened, particularly in relation to tuberculosis and acute lower respiratory infections. A
more systematic approach to the development and evaluation of interventions is desirable, with
clearer recognition of the interrelationships between poverty and dependence on polluting fuels.
PMID: 11019457 [PubMed - indexed for MEDLINE]

Gac Med Mex 1999 Mar-Apr;135(2):165-70
[Ketotifen (Zaditen and K-Asthmal): a drug with sales disproportionate to its demonstrated effectiveness]. [Article in Spanish]
Perez-Padilla JR.

Departamento de Fisiologia, Instituto Nacional de Enfermedades Respiratorias, Mexico, D.F.
perezpad@servidor.unam.mx

Ketotifen is a sedative antihistamine promoted heavily for asthma treatment. Controlled trials are
inconsistent: several did not find ketotifen better than placebo or cromoglycate. We do not have
published controlled trials against inhaled steroids, the comparison most important to evaluate the
efficacy of ketotifen. Ketotifen is poorly effective against exercise-induced asthma, and unable to
reduce bronchial hyperactivity. The sedation and delay in therapeutic effect is also bothersome.
Because of the uncertainties of its effect, ketotifen is not a first line drug against asthma, according
to several international guidelines. Despite this information, ketotifen represented 17% of all
antiasthmatic drug sales in Mexico in 1996, clearly exaggerated for the efficacy demonstrated.
Ketotifen for asthma can be substituted with advantage by inhaled cromoglycate or
corticosteroids. As a sedative antihistamine it is very expensive. The authorized publicity
concerning ketotifen should be reevaluated with the current information available.
PMID: 10327750 [PubMed - indexed for MEDLINE]

Gac Med Mex 1999 Jan-Feb;135(1):19-29
[The domestic inhalation of the smoke from firewood and of other
biological materials. A risk for the development of respiratory diseases].
[Article in Spanish]
Perez-Padilla JR, Regalado-Pineda J, Moran-Mendoza AO.

Instituto Nacional de Enfermedades Respiratorias, Tlalpan, Mexico.
perezpad@servidor.unam.mx

A high proportion of the world population, especially in developing countries, is exposed to
indoor pollutants produced by inefficient biomass stoves. The levels of pollutants, including toxins
and carcinogens in the kitchen are usually very high. This potential pathogenic exposure has been
scarcely studied. The exposure to biomass smoke has been associated to chronic bronchitis and
chronic airflow obstruction in adults and to acute respiratory infections in children. At the
National Institute of Pulmonary Diseases in Mexico, we have observed the entire spectrum of
diseases associated with tobacco in people who never smoked and who were exposed to wood
smoke. Women exposed to wood smoke had a five-fold risk of chronic bronchitis and chronic
airflow obstruction, as compared to the non-exposed, according to a recent case-control study
done at our Institute. The indoor levels of suspended particles smaller than 10 microns were
frequently above 1,000 micrograms/m3 in a rural community in the state of Mexico. This
information supports a causal role for biomass smoke for the genesis of several respiratory
diseases, representing a potentially public health problem.
PMID: 10204309 [PubMed - indexed for MEDLINE]

Rev Invest Clin 1998 Jul-Aug;50(4):323-9
[Normal ventilatory response to hypoxia and hypercapnia at an altitude of 2240 meters].
[Article in Spanish] Vazquez-Garcia JC, Arellano-Vega SL, Regalado-Pineda J, Perez-Padilla JR.

Departamento de Fisiologia Respiratoria, Instituto Nacional de Enfermedades Respiratorias,
INER, Mexico DF.

OBJECTIVE: To evaluate the ventilatory response to hypoxia and hypercapnia in healthy
residents of Mexico City at 2240 m above sea level. METHODS: 15 healthy subjects, 10
women and 5 men, were studied (mean age 38; range 26-76). All completed one or two tests of
ventilatory response to hypoxia and hypercapnia as described by Rebuck-Campbell and Read,
respectively. The results were analyzed by linear regression using the minute ventilation as the
dependent variable and SaO2 (hypoxia) or PCO2 (hypercapnia) as the independent variables.
RESULTS: Seven subjects had very low or no response to hypoxia. The mean hypoxia slope
was 0.7 +/- 0.6 L/min/% (+/- SD) and the hypercapnia slope was 3.0 +/- 1.4 L/min/mmHg. The
intercepts were 176 +/- 278 for SaO2 and 3.0 +/- 7 for PCO2. CONCLUSIONS: A low
respiratory response to hypoxia was found in Mexico City Healthy residents. The response to
hypercapnia was similar in slope to other studies but had an intercept shifted to lower values. The
Mexico City residents showed a behavior typical of patients with chronic hypoxemia or of
dwellers at high altitudes.
PMID: 9830321 [PubMed - indexed for MEDLINE]


Am J Respir Crit Care Med 1998 Jul;158(1):226-32
Antioxidant supplementation and respiratory functions among workers
exposed to high levels of ozone.
Romieu I, Meneses F, Ramirez M, Ruiz S, Perez Padilla R, Sienra JJ, Gerber M,
Grievink L, Dekker R, Walda I, Brunekreef B.

Pan American Health Organization; Instituto Nacional de Salud Publica, Cuernavaca, Mor;
Instituto de Investigacion en Matematica Aplicada y Sistemas, Universidad Autonoma de
Mexico, Mexico DF. iar9@cdc.gov

Ozone exposure has been related to adverse respiratory effects, in particular to lung function
decrements. Antioxidant vitamins are free-radical scavengers and could have a protective effect
against photo-oxidant exposure. To evaluate whether acute effects of ozone on lung functions
could be attenuated by antioxidant vitamin supplementation, we conducted a randomized trial
using a double-blind crossover design. Street workers (n = 47) of Mexico City were randomly
assigned to take daily a supplement (75 mg vitamin E, 650 mg vitamin C, 15 mg beta carotene)
or a placebo and were followed from March to August 1996. Pulmonary function tests were
done twice a week at the end of the workday. During the follow-up, the mean 1-h maximum
ozone level was 123 ppb (SD = 40). During the first phase, ozone levels were inversely
associated with FVC (beta = -1.60 ml/ppb), FEV1 (beta = -2.11 ml/ppb), and FEF25-75 (beta
= -4.92 ml/ppb) (p < 0.05) in the placebo group but not in the supplement group. The difference
between the two groups was significant for FVC, FEV1, and FEF25-75 (p < 0.01). During the
second phase, similar results were observed, but the lung function decrements in the placebo
group were smaller, suggesting that the supplementation may have had a residual protective effect
on the lung. These results need to be confirmed in larger supplementation studies.
Publication Types:
Clinical trial
Randomized controlled trial
PMID: 9655734 [PubMed - indexed for MEDLINE]


Rev Invest Clin 1998 May-Jun;50(3):221-6
The role of commercial plasmapheresis banks on the AIDS epidemic in Mexico.
Volkow P, Perez-Padilla R, del-Rio C, Mohar A.
Instituto Nacional de Cancerologia, Department of Infectious Diseases, Mexico D.F.

OBJECTIVE: To characterize the circumstances underlying the epidemic of AIDS associated
with blood transfusion in Mexico and to explore the possible mechanisms for its dissemination.
METHODS: A retrospective analysis comparing the total number of AIDS cases and
transfusion-associated AIDS cases and the male:female ratio reported in Mexico and the U.S.
from 1981 to 1996 was done. We analyzed the relationship between the location of
plasmapheresis banks and the geographic distribution of transfusion-associated AIDS cases and
AIDS cases among paid donors in order to assess the possible role of plasmapheresis banks in
its dissemination. RESULTS: The proportion of transfusion-associated AIDS in the total number
of cases was significantly higher in Mexico than in the U.S. from 1987 through 1996 (p < .0001).
A rapid drop in the male:female ratio of AIDS was observed in Mexico but not in the U.S.
coinciding with a growing number of transfusion associated cases; transfusion has been the main
risk factor for AIDS in women in our country. In 1986, seven States and Mexico City had
plasmapheresis banks: they reported 90% of the cases associated to paid donation and 75% of
those associated to transfusion, despite the fact that commercial blood banks without
plasmapheresis facilities existed in 23 of the other 24 States. CONCLUSION: There was a
difference on the frequency of transfusion associated AIDS between Mexico and the U.S. which
reached epidemic proportions in Mexico. We believe that plasmapheresis banks played a major
role in the dissemination of the infection in Mexico as paid donors provided a third of the blood
used in Mexico in 1986. These findings highlight important implications for the prevention of
AIDS in developing countries where commercial plasmapheresis practices are still in operation.
PMID: 9763887 [PubMed - indexed for MEDLINE]

Arch Med Res 1998 Spring;29(1):57-62
Gas exchange at rest during simulated altitude in patients with chronic lung disease.
Chi-Lem G, Perez-Padilla R.

Department of Respiratory Physiology, National Institute of Respiratory Diseases, Mexico, D.F.,
Mexico.

BACKGROUND: To characterize the gasometric and oximetric response to simulated altitudes
of 3,100 m and sea level of patients with Chronic Obstructive Pulmonary Disease (COPD) and
Interstitial Lung Disease (ILD) studied at 2,240 m above sea level. METHODS: Consecutive
stable patients with COPD and ILD were studied at the National Institute of Respiratory
Diseases, a referral center for pulmonary diseases in Mexico City, and a healthy control group.
The patients breathed room air (FIO2 = 0.21), for at least 15 min, then, a hypoxic mixture (FIO2
= 0.18, simulating 3,100 m), and finally, a hyperoxic mixture (FIO2 = 0.28, simulating sea level).
Arterial blood gases and oxygen saturation were measured by a pulse oximeter at the end of each
stage. RESULTS: Twelve patients with COPD, 13 patients with ILD and 11 healthy controls
were studied. The PaCO2 and pH were constant in the three study stages in both groups of
patients and controls. A slope of PaO2 vs. altitude of 9 Torr per Km was found for each of the
study's patients, either by simple linear regression or multiple regression, which is identical to that
previously obtained at sea level with COPD patients (Gong et al.). Oxygen desaturation per Km
of altitude change was alinear, higher for the hypoxic than for the hyperoxic challenge and more
severe for the most hypoxic patients. CONCLUSIONS: Exposure tests to simulated altitudes are
safe, and orient the physician concerning the patient's condition at altitudes different from the
place where the measurement is done. Alveolar ventilation remains constant despite hypoxia or
hyperoxia during the challenges. A computer model of the lung reproduces many of the findings in
the challenges of this study.
PMID: 9556924 [PubMed - indexed for MEDLINE]

Am J Respir Crit Care Med 1996 Sep;154(3 Pt 1):701-6
Exposure to biomass smoke and chronic airway disease in Mexican women. A case-control study.
Perez-Padilla R, Regalado J, Vedal S, Pare P, Chapela R, Sansores R, Selman M.

National Institute of Pulmonary Diseases, Mexico City, DF, Mexico.

A case-control study was performed in women older than 40 yr of age to evaluate the risk of
cooking with traditional wood stoves for chronic bronchitis and chronic airway obstruction
(CAO). The subjects were recruited from patients attending a referral chest hospital in Mexico
City. We selected 127 patients with chronic bronchitis or CAO, of which 63 had chronic
bronchitis alone, 23 had CAO alone (FEV1 less than 75% of predicted), and 41 had both
chronic bronchitis and CAO (cases). Four control groups were selected: 83 patients with
pulmonary tuberculosis, 100 patients with interstitial lung diseases, 97 patients with ear, nose and
throat ailments, and 95 healthy visitors to the hospital (controls). Exposure to wood smoke,
assessed as any or none, and as hour-years (years of exposure multiplied by average hours of
exposure per day) was significantly higher in cases than in controls. Crude odds ratios for wood
smoke exposure were 3.9 (95% CI, 2.0 to 7.6) for chronic bronchitis only, 9.7 (95% CI, 3.7 to
27) for CAO plus chronic bronchitis, and 1.8 (95% CI, 0.7 to 4.7) for CAO only. Differences in
exposure to wood smoke persisted after adjusting by stratification and logistic regression for age,
income, education, smoking, place of residence, and place of birth. Risk of chronic bronchitis
alone and chronic bronchitis with CAO increased linearly with hour-years of cooking with a
wood stove; odds ratios for exposure to more than 200 hour-years compared with nonexposed
were 15.0 (95% CI, 5.6 to 40) for chronic bronchitis only and 75 (95% CI, 18 to 306) for
chronic bronchitis with CAO. The findings support a causal role of domestic wood smoke
exposure in chronic bronchitis and chronic airflow obstruction.
PMID: 8810608 [PubMed - indexed for MEDLINE]

Chest 1996 Aug;110(2):371-7
Bronchiolitis in chronic pigeon breeder's disease. Morphologic evidence of
a spectrum of small airway lesions in hypersensitivity pneumonitis induced
by avian antigens.
Perez-Padilla R, Gaxiola M, Salas J, Mejia M, Ramos C, Selman M.

Instituto Nacional de Enfermedades Respiratorias, Mexico, DF, Mexico.

We analyzed 36 open lung biopsy specimens from patients with chronic pigeon breeder's disease
(PBD) to assess bronchiolar involvement and its relationship to the parenchymal pathologic
abnormalities. Likewise, 21 biopsy specimens obtained from patients with usual interstitial
pneumonia (UIP) were also examined. The bronchiolar abnormalities were scored by the method
of Wright et al using a panel of photographs. In addition, the severity of lung fibrosis was
evaluated in all samples and expressed as percentage in multiples of ten. A variable degree of
epithelial cell metaplasia, bronchiolar inflammation and fibrosis, smooth muscle hypertrophy,
extrinsic small airways narrowing, and intraluminal macrophages was observed in both diseases.
Occasionally, hyperplasia of lymphoid follicles was also present. Bronchiolar changes were
proportional in type and severity to the parenchymal damage. Spearman's nonparametric
correlation between fibrosis in parenchyma and fibrosis in membranous bronchiole for the
complete group (including patients with UIP and with PBD) showed a moderate but significant
association (R = 0.51; p < 0.01). A significant association was also demonstrated when the score
for bronchiolar fibrosis and inflammation was evaluated in relation to lung fibrosis divided in high
degree (> 50%) and low degree (< 50%), respectively. In the case of patients with PBD, the
correlation between bronchiolar and parenchymatous fibrosis was of 0.33 (p < 0.05). In general,
bronchiolar fibrosis was less severe and inflammation more severe in PBD lungs compared with
patients with UIP. Fibrosis in membranous bronchioles correlated with increased mortality in the
complete group of patients, but the impact on mortality disappeared after correcting for overall
fibrosis in the biopsy sample. Our findings demonstrate that a spectrum of bronchiolar lesions is
usually observed in chronic PBD lungs, although the predominant pattern is similar to that found in
the surrounding parenchyma, suggesting that the damage occurs in parallel.
PMID: 8697836 [PubMed - indexed for MEDLINE]

Arch Inst Cardiol Mex 1989 May-Jun;59(3):301-7
[Cardiovascular abnormalities in Ehlers-Danlos syndrome. Report of a case].
[Article in Spanish]
Zamora Mucino A, Gomez Jaume A, Gorodezky M, Perez Padilla R, Amigo MC,
Barrios R.

Instituto Nacional de Cardiologia Ignacio Chavez, Mexico. D.F.

This is the case of a 34-year-old woman with Ehlers-Danlos syndrome whose cardiopulmonary
manifestations are the following: Prolapse of mitral and tricuspid valves. Aneurysmal dilatation of
main arteries without aortic or pulmonary insufficiency. Disturbances in pulmonary function tests
and pulmonary arterial hypertension. The diagnosis was verified by skin biopsy and an electron
microscopic study. Due to the clinical and histopathological characteristics, we have considered
this case to be a non-specified type of the 10 varieties described up to now, and have decided to
report it also because of the interesting findings in the hemodynamic and pulmonary function tests.
PMID: 2782994 [PubMed - indexed for MEDLINE]

Lung 1988;166(5):287-91
PaO2 increases with coughing in patients with chronic lung disease.
Martinez W, Sandoval J, Perez-Padilla R, Maxwell R, Seoane M, Lupi-Herrera E.
Cardiopulmonary Service, Instituto Nacional de Cardiologia Ignacio Chavez, Mexico City,
Mexico.

We considered if the cyanosis frequently observed during a cough attack in patients with chronic
lung disease was due to worsening hypoxemia. To investigate the effects of cough on PaO2, we
measured arterial blood gases before and after a voluntary coughing period of 45 sec, in 11
patients with Interstitial Lung Disease (ILD) and 14 patients with Chronic Obstructive Lung
Disease (COPD). All patients significantly increased (p less than 0.05) their PaO2 (COPD: from
49 +/- 2 to 60 +/- 2 mmHg; ILD from 44 +/- 2 to 51 +/- 3 mmHg, mean +/- SD) and
decreased their PaCO2. We conclude that stable patients with COPD and ILD increase their
PaO2 with coughing most likely due to hyperventilation. The cyanosis observed could be due to
peripheral circulatory effects of coughing.
PMID: 3146675 [PubMed - indexed for MEDLINE]

Sleep 1987 Jun;10(3):249-53
Snoring in normal young adults: prevalence in sleep stages and associated
changes in oxygen saturation, heart rate, and breathing pattern.

Perez-Padilla JR, West P, Kryger M.

Six men and three women, asymptomatic light snorers ranging in age from 25-34 years, were
studied during sleep to determine the prevalence of snoring in the different sleep stages, the
associated changes in oxygen saturation (SaO2), heart rate (HR), and breathing frequency (f),
and the associated breathing arrhythmias. Snoring was defined as a 1-minute epoch with more
than 80% of the breaths associated with snores. Most of the snoring epochs as well as the
apneas and hypopneas occurred during stage 2, mainly because it is the most prolonged sleep
stage. The prevalence of snoring, however, normalized for differences in length of sleep stages,
was highest in stages 3 and 4 but low in REM, whereas the converse was true for apneas and
hypopneas. Snoring caused no change in the mean SaO2, mean HR, or f, as compared with
nonsnoring periods in the same sleep stage. Continuous snoring in normal subjects can occur
without significant O2 desaturation or breathing arrhythmia. Continuous snoring and breathing
arrhythmia tended to occur together in a given subject but were unrelated in time, suggesting a
different pathogenesis.
PMID: 3629087 [PubMed - indexed for MEDLINE]

Sleep 1987 Jun;10(3):216-23
Hypercapnia and sleep O2 desaturation in chronic obstructive pulmonary
disease.

Perez-Padilla R, Conway W, Roth T, Anthonisen N, George C, Kryger M.

There is a wide clinical spectrum in chronic obstructive pulmonary disease (COPD). The
extremes of this spectrum, the "pink puffer" (PP) and "blue bloater" (BB) stereotypes differ in
their degree of sleep hypoxemia and pulmonary hypertension. Most patients cannot be
characterized as either PP or BB. The data amassed in the recent nocturnal oxygen therapy trial
provide an opportunity to see to what extent differences in sleep oxygenation and hemodynamics
in a large hypoxemic COPD population are related to awake hypoxemia and hypercapnia. From
a large hypoxemic COPD population sleep SaO2 was examined in those with (PaCO2 greater
than 44 mm Hg) and without (PaCO2 less than or equal to 44 mm Hg) hypercapnia.
Hypercapnic patients (mean PaCO2 49.8 mm Hg) had the same PaO2 and degree of airflow
obstruction as normocapnic patients (PaCO2 37.4 mm Hg) but had far greater sleep hypoxemia
(measured by mean sleep SaO2, low sleep SaO2, and awake-low sleep SaO2, p less than
0.05). In addition, arterial blood gases of the large sleep O2 desaturaters were compared with
those of the small desaturaters; PaO2 was similar in both groups, whereas PaCO2 was different
(p less than 0.01). Two common subsets of hypoxemic patients were also compared; one was
hypercapnic and overweight, the other normocapnic and hyperinflated. We found that patients in
the hypercapnic group had far worse sleep hypoxemia, although they had better lung function.
We conclude that hypercapnia is a marker for sleep O2 desaturation in hypoxemic COPD.

PMID: 3629083 [PubMed - indexed for MEDLINE]

Chest 1987 Mar;91(3):444-9
Perfluorochemical artificial blood as a volume expander in hypoxemic respiratory failure in dogs.
Light RB, Perez-Padilla R, Kryger MH.

The perfluorochemical O2-transport fluid, Fluosol-DA 20 percent (PFC), is being clinically
evaluated as a volume expander in patients who are unable to receive blood products. Since
patients treated with Fluosol-DA may be at risk of developing adult respiratory distress
syndrome (ARDS) as a complication of the original disorder for which they were transfused, we
examined central hemodynamics and gas exchange in anesthetized O2-ventilated dogs with
oleic-acid induced pulmonary edema before and after transfusion with 400 ml of either PFC (n =
5) or whole blood (n = 5). Transfusion produced similar increases in cardiac output, pulmonary
and systemic vascular pressures and intrapulmonary shunt in the two groups. Arterial O2 tension,
however, fell from 209 +/- 117 to 172 +/- 81 mmHg in the blood transfused group but increased
from 219 +/- 145 to 302 +/- 138 mmHg in the PFC group. Arterial O2 content, on the other
hand, increased in the blood transfused group due to an increase in hematocrit, but fell with PFC
because of hemodilution. This lower total arterial O2 content in the PFC group was, however,
compensated for by more efficient O2 transport by the PFC in that the PFC arteriovenous O2
content difference accounted for 26 percent of the total arteriovenous O2 content difference,
making it about four times as efficient as hemoglobin in tissue O2 delivery. Fluosol DA, 20
percent, is an effective volume expander in this model of hypoxemic respiratory failure, and it can
transport significant amounts of O2 even in the presence of a substantial intrapulmonary shunt.
PMID: 3816321 [PubMed - indexed for MEDLINE]


Arch Inst Cardiol Mex 1986 Jul-Aug;56(4):303-7
[Accuracy of an the ear oximeter Biox-III and its sensitivity to carboxyhemoglobin in Mexico City].
[Article in Spanish]

Perez-Padilla JR, Bracamonte-Peraza R, Manrique G, Ruiz-Primo ME.

Ear oximeters estimate arterial oxygen saturation (Sa02) measuring the characteristics of light
transmission through the ear lobe. We tested the accuracy of a new ear oximeter (Biox-III) in
Mexico City comparing its estimates (Sa02OXI) with Sa02 measured by a Co-Oximeter, in a
simultaneously taken arterial blood sample. We used two indexes in the arterial sample: Sa02 of
the total hemoglobin (Sa02T) given directly by the Co-Oximeter and Sa02 of the hemoglobin
available for oxygenation (Sa02A) which corrects for the presence of carboxyhemoglobin and
metahemoglobin. We studied 21 subjects with a total of 100 simultaneous samples with a Sa02T
ranging from 36.2% to 97.2%. The samples were obtained with the subjects resting, during light
exercise, during rebreathing and increasing the Fi02. Spearman and Pearson's correlation
coefficients between Sa02OXI and Sa02A were 0.97, and between Sa02OXI and Sa02T were
0.96. Lineal regression equations were: Sa02T = 2.047 (Sa02OXI) -8.5 and Sa02A = 1.102
(Sa02OXI) -9.32. Slopes of the equations and correlation coefficients were statistically
significant (P less than 0.001). Mean error of Sa02OXI compared with Sa02T
(Sa02T-Sa02OXI) was -4.4% and compared with Sa02A (Sa02A-Sa02OXI) was -0.4%, with
a standard deviation of 3.4% and 3.5% respectively. In the presence of carboxyhemoglobin the
ear oximeter overestimates Sa02T but not Sa02A. Measurement error increases during
rebreathing maybe because error increases at low Sa02 and because of the delay in oximeter's
response in a situation of a continuously falling Sa02.Ear oximeter Biox-III estimates Sa02 in
Mexico City as accurately as the Biox-IIA at sea level. Sa02 measurement is quick, easy,
continuous and non-invasive, which increase its potential clinical and research application.
PMID: 2945522 [PubMed - indexed for MEDLINE]


Am Rev Respir Dis 1985 Aug;132(2):224-9
Breathing during sleep in patients with interstitial lung disease.
Perez-Padilla R, West P, Lertzman M, Kryger MH.

Patients with interstitial lung disease (ILD) have a rapid shallow breathing pattern while awake
that is thought to be due to activation of lung reflexes. We wondered whether sleep would result
in changes in respiratory control and thus cause hypoxemia and poor sleep quality. Eleven
patients with ILD (5 men and 6 women) and 11 age- and sex-matched control subjects were
studied during sleep. Sleep quality was worse in patients with ILD, with more time in Stage 1
(33.7% of total sleep time (TST) versus 13.5%) and less time in REM sleep (11.8 versus 19.9%
TST) than found in control subjects, and more fragmentation of sleep (13.7 +/- 3.1 arousals/h
and 24.3 +/- 6.0 sleep stage changes/h versus 6.9 +/- 1.0 and 12.7 +/- 1.4, respectively).
Patients with ILD with awake SaO2 less than 90% had greater abnormalities in sleep structure
than did those with SaO2 greater than 90%. The incidence of apneas and hypopnea periods in
patients with ILD was low (apnea plus hypoventilation index of 1.3 +/- 0.45 versus 2.9 +/- 0.82
in control subjects, p = NS). Oxygen saturation dropped during REM sleep in patients, especially
in those with more severe awake hypoxemia. Expiratory time (Te), inspiratory time (Ti), and their
sum (Ttot) were shorter in the patients, whereas Ti/Ttot was the same as in control subjects. No
systematic changes during sleep were seen in these variables. The variability of inspiratory volume
index, Ti, Te, and Ti/Ttot was similar to that in control subjects, and was lowest during NREM
sleep. The incidence of snoring was comparable in patients and control subjects.(ABSTRACT
TRUNCATED AT 250 WORDS)
PMID: 2411177 [PubMed - indexed for MEDLINE]

Bull Eur Physiopathol Respir 1983 Nov-Dec;19(6):621-4
The role of protriptyline in obstructive sleep apnea.
Brownell LG, Perez-Padilla R, West P, Kryger MH.

Protriptyline, a non-sedating tricyclic agent, was evaluated in a double blind drug-placebo
crossover trial in five obese patients with obstructive sleep apnea. Four of the five patients had
improvement in somnolence. Protriptyline improved oxygenation. This seemed related primarily
to a reduction (from 23% to 11%) in REM, with fewer of the more severe REM apneas. Arousal
frequency remained quite high; thus the reason for the reduction in somnolence remains unclear.
In three patients, at six months the improvement in clinical status and oxygenation persisted. We
have now attempted long term treatment in nine patients. In five, anticholinergic side-effects
necessitated stopping therapy. Four patients continue to do well. A trial of protriptyline is thus
indicated in treatment of mild to moderate obstructive apnea or when the patient refuses more
invasive treatment.

Publication Types:
Clinical trial
PMID: 6360257 [PubMed - indexed for MEDLINE]

Sleep 1983;6(3):234-43
Sighs during sleep in adult humans.
Sleep 1987 Jun;10(3):216-23
Perez-Padilla R, West P, Kryger MH.

We analyzed sighs (breaths with a tidal volume at least twice that of baseline breaths) during
sleep in 12 normal adults. We found a total of 124 sighs in the group, with an average of 1.66
sighs/h of sleep, but with great intersubject variation (range: 1-25 sighs/night). There were sighs in
all sleep stages, but there were more per hour in stage 1. 64.4% of the sighs were associated
with an increase in EMG activity or EEG frequency, starting either before or immediately after the
sigh. The remainder of the sighs were not associated with any arousal or sleep stage changes. The
normal variability of heart rate with breathing is exaggerated during sighs, probably because of the
greater inflation and the associated arousal. Sighs have larger mean inspiratory flows (Vt/Ti),
expiratory flows (Vt/Te), and a larger fraction of respiratory cycle spent in inspiration (Ti/Ttot)
than the previous breaths, all evidence of a change in respiratory control. Sighs during sleep may
occasionally be followed by central apneas, hypoventilation, or considerable slowing of
respiratory rate. Although it has been shown that a sigh renders the respiratory centers refractory
to another sigh, we found that sighs sometimes occur in pairs.
PMID: 6622880 [PubMed - indexed for MEDLINE]


Lung 1996;174(5):315-23
Correlation between pulmonary fibrosis and the lung pressure-volume curve.
Sansores RH, Ramirez-Venegas A, Perez-Padilla R, Montano M, Ramos C, Becerril C,
Gaxiola M, Pare P, Selman M.

Instituto Nacional de Enfermedades Respiratorias, Mexico City, Mexico.

The severity of pulmonary fibrosis is the main prognostic factor for survival of patients with
interstitial lung diseases (ILD). Unfortunately, lung biopsy, which is the best method to assess
fibrosis quantitatively, is done only once during the evolution of the disease. In this study we
analyzed the relationship between the degree of fibrosis and the exponential constant k, derived
from the lung pressure-volume curve (LPVC) in 33 patients with chronic ILD, 19 with pigeon
breeder's disease (PBD), and 14 with idiopathic pulmonary fibrosis (IPF). Pulmonary function
tests, including the LPVC, were obtained before biopsy. A semiquantitative histologic assessment
of the severity of fibrosis was performed on lung tissues. All patients showed a decrease of total
lung capacity, residual volume, compliance, and Pao2. The mean value of the constant k was
0.08 +/- 0.06. When expressed as a percent of normal values, 25 patients exhibited values of k
lower than 70% of predicted; of the remaining 8 patients whose values were above 70% of
predicted, 7 had PBD and only one IPF. On morphologic analysis, 19 patients displayed more
than 50% fibrosis. No significant correlations were found between the extent of the lesion or
severity of lung fibrosis and the conventional pulmonary function tests. By contrast, a moderate
but significant correlation was found between k and the severity of lung fibrosis (r = -0.38, p <
0.05). These findings show that the shape of the LPVC, represented by the constant k, predicts
the degree of lung fibrosis and could be useful in the clinical assessment and follow-up of patients
with ILD.
PMID: 8843057 [PubMed - indexed for MEDLINE]

Rev Invest Clin 1995 Mar-Apr;47(2):95-101
[Capability of clinical and laboratory findings to predict the grade of
fibrosis and the diagnosis in diffuse interstitial lung diseases].
[Article in Spanish]
Perez-Padilla R, Gaxiola M, Salas J, Sansores R, Chapela R, Carrillo G, Selman M.

Instituto Nacional de Enfermedades Respiratorias, Mexico, D.F.

Our objective was to assess the capacity of clinical and laboratory information to predict findings
in the lung biopsy in interstitial lung diseases (ILD). We studied 121 patients with ILD as a cohort
recruited in our institute from 1983 to 1987 with the diagnosis of hypersensitivity pneumonitis
(HP) and usual interstitial pneumonia (UIP). Histologic diagnosis (HP vs UIP) and degree of
fibrosis (< 50% of the biopsy surface vs > or = 50%) were used as the gold standard to
compare a series of clinical and laboratory variables in the initial assessment. We used a stepwise
logistic regression model to predict the biopsy results. The model was calculated in half of the
patients selected by random sampling, and the calculated model was tested in the other half of the
patients. Variables found to predict degree of fibrosis were (with relative risk RR and 95%
confidence interval): a radiographic pattern of honeycombing (RR 5.0 from 0.9-29), digital
clubbing (RR 8 from 1.4-48) and gender (RR 2.9 from 0.4-20). This model classified correctly
72% of the biopsies, with a sensitivity of 0.38, a specificity of 0.85 and a kappa of 0.25 +/- 0.19
(p = 0.17 NS). For histologic diagnosis (NIU vs NH), the model included gender (RR 6.6,
1.3-33), honeycombing (RR 1.6, from 0.4-6.0), digital clubbing (RR 4.6, from 1.2-18), and vital
capacity expressed as percent of predicted (RR 0.96, from 0.92-1.00).(ABSTRACT
TRUNCATED AT 250 WORDS)

PMID: 7610289 [PubMed - indexed for MEDLINE]


Clin Chest Med 1993 Dec;14(4):699-714
Airflow obstruction and airway lesions in hypersensitivity pneumonitis.
Selman-Lama M, Perez-Padilla R.

Clinical Research Division, Instituto Nacional de Enfermedades Respiratorias, Tlalpan, Mexico.

Peripheral airways of lung biopsies from patients with HP commonly show several morphologic
changes, including inflammation, fibrosis, or both. In most cases, damage of the airways is parallel
to damage of surrounding parenchyma and the functional result is lung restriction, perhaps with
alterations in the so-called "small airway tests." Chronic cough and phlegm also are more
common in subjects exposed to organic antigens. Overt airflow obstruction is present in a number
of patients with HP, and they usually have other risk factors, such as asthma, cigarette smoking,
or dust inhalation. There are limited studies of patients who have HP and CAO but not
concomitant risk factors for CAO, making it difficult to reach any firm conclusion about their
association. In most cases, the lesion that could explain severe airflow obstruction seems to be
located in bronchioles but, based on several clinical reports, there is the possibility that HP
occasionally ends in emphysema.
Review
Review, tutorial
PMID: 8313674 [PubMed - indexed for MEDLINE]

Am Rev Respir Dis 1993 Jul;148(1):49-53
Mortality in Mexican patients with chronic pigeon breeder's lung
compared with those with usual interstitial pneumonia.
Perez-Padilla R, Salas J, Chapela R, Sanchez M, Carrillo G, Perez R, Sansores R,
Gaxiola M, Selman M.

Instituto Nacional de Enfermedades Respiratorias, Mexico City, Mexico D.F.

The clinical course of chronic pigeon breeder's lung (CPBL) is unknown, especially in
comparison with usual interstitial pneumonia (UIP). We studied a cohort of 125 consecutive
patients with interstitial lung diseases, including 78 patients with CPBL (74 biopsied) and 47
patients with UIP in the lung biopsy. Patients with UIP were divided into 17 without bird
exposure (UIP) and 30 with bird exposure (UIP + BE). All patients were treated with
corticosteroids and followed for 33 +/- 23 months. The best predictors of mortality (Cox
proportional hazards model) were age > 44 yr, with a relative risk (RR) of 2.5 and 95%
confidence interval (CI) of 1.4 to 4.7, masculine gender (RR 4.0, CI 2.1 to 7.6), x-ray
honeycombing (RR 7.0, CI 3.8 to 12.7), and severity of fibrosis in the lung biopsy (RR 4.8, CI
2.3 to 9.7). Survival in CPBL 5 yr after diagnosis was 0.71 (SEM 0.08) and in UIP was 0.23
(SEM 0.08), with no statistical difference between UIP + BE and UIP. After adjusting for
severity of fibrosis and honeycombing, however, the correlation of diagnosis with survival
disappeared. In conclusion, mortality in CPBL is considerable, but lower than in UIP. Lung
fibrosis and honeycombing seem to be a final common pathway for the ILD. Adjusting for them,
the effect of diagnosis in survival is not significant.
PMID: 8317813 [PubMed - indexed for MEDLINE]

Am Rev Respir Dis 1993 Mar;147(3):635-44
Characteristics of the snoring noise in patients with and without occlusive
sleep apnea.
Perez-Padilla JR, Slawinski E, Difrancesco LM, Feige RR, Remmers JE, Whitelaw
WA.
Department of Medicine, University of Calgary, Alberta, Canada.

We analyzed snoring noise from 10 nonapneic heavy snorers and nine patients with obstructive
sleep apnea (OSA). Sound was recorded simultaneously through two microphones, one attached
to the manubrium sterni and one suspended in the air 15 cm from the patient's head. Signals were
stored on magnetic tape, digitized, and displayed in the time and frequency domains. Most of the
power of snoring noise was below 2,000 Hz, and the peak power was usually below 500 Hz.
When snores were generated during nose-only breathing (nasal snores), the sound spectrum was
made up of a series of discrete, sharp peaks, with a fundamental note and harmonics similar to
the spectrum of voiced sounds. When snores were generated during breathing through nose and
mouth (oronasal snores), the spectra showed a mixture of sharp peaks and broad-band white
noise. Patients with apnea showed a sequence of snores with spectral characteristics that varied
markedly through an apnea-respiration cycle. The first postapneic snore consisted mainly of
broad-band white noise with relatively more power at higher frequencies, so that the ratio of
power above 800 Hz to power below 800 Hz could be used to separate snorers from patients
with OSA. Other breaths in the cycle resembled oronasal or nasal snores in nonapneic subjects.
Characteristics of the noise give information about the possible mechanism of sound generation
and thus about the behavior of the pharynx during snoring. Quality of snoring sound may help to
separate patients with obstructive apnea from those with simple snoring.
PMID: 8442599 [PubMed - indexed for MEDLINE]


Rev Invest Clin 1992 Jul-Sep;44(3):353-62
[Gasometric values reported in healthy subjects from the Mexican
population: review and analysis].
[Article in Spanish]
Perez Martinez SO, Perez-Padilla JR.

Departamento de Fisiologia Pulmonar, Instituto Nacional de Enfermedades Respiratorias,
Mexico, D.F.

We do not know the normal relationship between altitude and PaCO2 in Mexico. We collected
and analyzed the reports of reference values for gasometry in Mexico City (2240 m above sea
level and a mean barometric pressure of 585 Torr) and other places in the country. The reports
include arterial, capillary and expired gases in children and adults, with measurements done in
resting and exercising subjects, breathing room air and 100% oxygen. In Mexico City we found
18 studies in normal subjects reporting a mean PaCO2 ranging from 25.5 to 38.4 Torr.
Averaging arterial studies from children and adults, adjusting for the number of subjects studied,
and discarding data with mean pH below 7.37 or above 7.43 (suggesting non steady state), 10
studies with a total of 581 subjects have the following average values (Torr, means and SD):
PaCO2 = 31.1 +/- 2.6, PaO2 = 67.7 +/- 2.6, calculated PAO2 and P(A-a)O2 73.6 +/- 3.3 y
6.1 +/- 3.7 respectively. The PaCO2 found was much lower than that reported for native
Peruvians in the Andes who have a mean PaCO2 of 37.8 Torr at an altitude of 2390 m, and a
mean PaCO2 of 33.0 Torr only at 4860 m above the sea level. On the other hand, the average
values in Mexico are similar to those found in North Americans who have a mean PACO2 of
33.1 Torr at 2131 m of altitude, a mean PACO2 of 30.7 at 2371 m and a mean PaCO2 of 31
Torr at 2238 m. Normal values for gasometry in Mexico are scarce and some of the existing
ones are erroneous probably due to lack of adequate calibrations and to poor quality control.
Values of PaCO2 in Mexico are more similar to those found in the USA than to those found in
Peruvian natives.
Publication Types:
Meta-analysis
PMID: 1488580 [PubMed - indexed for MEDLINE]

Chest 1992 Jun;101(6):1691-3
Prevalence of high hematocrits in patients with interstitial lung disease in
Mexico City.
Perez-Padilla R, Salas J, Carrillo G, Selman M, Chapela R.
Instituto Nacional de Enfermedades Respiratorias, Mexico City.

Erythrocytosis, a known response to chronic hypoxemia, is considered infrequent in interstitial
lung diseases. We studied the prevalence of high hematocrit (Hct) values and the relationship
between Hct and SaO2 in 79 patients with chronic pigeon breeder's lung (PBL) and 34 with
idiopathic pulmonary fibrosis (IPF), all of whom lived in the Mexico City metropolitan area
(2,240 m above sea level). Lung biopsy was performed in 31 patients with IPF and 71 with
PBL. We analyzed only one simultaneous measurement of Hct and SaO2 per patient (usually the
initial measurement) before treatment. No additional cause for anemia or erythrocytosis was
detected. Forty-eight percent of the patients with PBL (38/79) and 62 percent of those with IPF
(21/34) had high Hct values (greater than 2 SD above mean values for Mexico City); in 14 (12.3
percent) of the 113 patients (nine with PBL and five with IPF), the Hct was above 60 percent.
The Hct and SaO2 values displayed a poor correlation for the whole group: Hct =
65.7-0.16(SaO2), r = 0.24, p = 0.012. The correlation between Hct and SaO2 was
nonsignificant if patients were separated by diagnosis. For an SaO2 of less than 80 percent, the
slope of SaO2 vs Hct was zero. Half of our patients with PBL and IPF had Hct values that were
high for the altitude. In most cases, Hct responses fell within the confidence limits reported as
normal at high altitudes. We found a poor relationship between Hct and awake SaO2.
PMID: 1600793 [PubMed - indexed for MEDLINE]

Chest 1992 May;101(5):1352-6
Exponential analysis of the lung pressure-volume curve in patients with
chronic pigeon-breeder's lung.
Sansores R, Perez-Padilla R, Pare PD, Selman M.

Departamento de Fisiologia Pulmonar, Instituto Nacional de Enfermedades Respiratorias
(INER), Mexico City.

Pigeon-breeder's lung (PBL) is extremely common in Mexico City and often progresses to
irreversible pulmonary fibrosis. The exponential analysis of the lung pressure-volume (PV) curve
(V = A - Be-kp) has been suggested as a method to separate the lung restriction caused by
inflammation from that caused by pulmonary fibrosis; a significantly decreased value for the
exponential constant, k, suggests a change in the mechanical properties of the functioning lung
parenchyma, while a normal value accompanied by restriction suggests subtraction of lung units
without a change in the mechanical properties of the functioning units. We measured lung volumes
and static PV curves in 29 patients who had persistent lung restriction following a biopsy-proven
diagnosis of PBL. Mean values in the 29 subjects were as follows: age, 43 +/- 13 years; TLC,
61 +/- 15 percent of predicted; VC, 46 +/- 19 percent of predicted; and k, 55 +/- 17 percent of
predicted. Twenty-four of the 29 patients had values for k that were below the 95 percent
confidence level, and five had "normal" values. There was no difference in TLC and VC (percent
of predicted) between those with or without a decreased value for k. Four of five patients with a
normal value for k improved subsequent to diagnosis, while only one of 21 patients with a
decreased k improved. We conclude that increased lung elasticity manifested by a low value for
k is common in patients with chronic PBL. These results support the observation of frequent
irreversible lung fibrosis in these patients. Measurements of k could prove a good prognostic
indicator at the time of initial diagnosis.
PMID: 1582296 [PubMed - indexed for MEDLINE]

Chest 1991 Jan;99(1):152-4
Behavior of the pulmonary circulation at rest and during exercise in
miliary tuberculosis.
Sandoval J, Cicero R, Seoane M, Perez-Padilla R, Quesada A, Lupi-Herrera E.
Cardiopulmonary Service Instituto Nacional de Cardiologia Ignacio Chavez, Mexico City,
Mexico.

We studied the hemodynamic behavior of the pulmonary circulation at rest and during exercise in
six patients with MTB. As a group, in contrast to advanced fibrocaseous tuberculosis, these
patients exhibited normal pulmonary hemodynamics at rest and during exercise. Only minor
abnormalities in pulmonary vascular resistance at exercise (increased PAd-PWP gradient) were
noted in two of the patients. The increase in Rp during exercise does not appear to be related to
acute hypoxic vasoconstruction but rather to functional changes (compliance or recruitment or
both) of the pulmonary microvasculature. In the genesis of these functional changes, chronic
alveolar hypoxia and the inflammatory-fibrotic process might be interacting.
PMID: 1984947 [PubMed - indexed for MEDLINE]


Rev Invest Clin 1991 Jan-Mar;43(1):87-98
[The challenge of evaluating clinical competence].
[Article in Spanish]
Viniegra L, Jimenez JL, Perez-Padilla JR.

Division de Estudios de Posgrado e Investigacion, Facultad de Medicina, UNAM.

The study is divided in two parts. The first one deals with theoretical aspects of evaluation. In the
second part, the development of an instrument intended to explore clinical competence is
presented. The importance of considering evaluation as part of a research process is emphasized
in the first part. The diverse theoretical and action trends in the field of education are synthetized
in two main tendencies: the active-participating and the passive-receptive. The influence of these
two tendencies in the selection the objects for evaluation is also discussed. An evaluation
instrument developed by us to explore clinical competence is placed within the
active-participating tendency of education; the present state of this instrument is given in the
second part. The instrument consists of multiple choice options of the true, false, don't know
type. The instrument in its present version is the result of a long validation process. It explores
particularly iatrogenic behaviors by omission or commission. The sample studied were 457
applicants for specialization courses in medicine. Of these, 127 were foreign applicants. The
instrument was applied to the whole sample in one single session. The results showed a low
general clinical competence, with similar results in mexican and foreign applicants. A clear
difference was found in commission iatrogenia which was significantly more frequent than
omission iatrogenia. The theoretical superiority of our test in relation the others is discussed

Salud Publica Mex 1990 Jan-Feb;32(1):3-14
[Ethical attitudes related to problems of managing patients with acquired
immunodeficiency syndrome].
[Article in Spanish]
Perez-Padilla JR, Ponce de Leon-Rosales S.

Departamento de Fisiologia Pulmonar del Instituto Nacional de Enfermedades Respiratorias.

We evaluated, with a questionnaire, ethical attitudes towards the clinical attention of patients with
AIDS in 88 physicians. Most of the surveyed were residents and all were working in two
mexican hospitals with experience managing patients with AIDS: The National Institute of
Nutrition and the National Institute of Respiratory Diseases. None of the questions was answered
similarly by all physicians and some of them considered ethically unquestionable, behaviours that
traditionally are immoral or even illegal. Reproducibility of the results, evaluated in 10 doctors 5
months later, was acceptable. Ethical attitudes were heterogeneous and inconsistent in the
surveyed. This can be the results of a poor or absent training in Medical Ethics in medical schools
and during residencies. We believe this deficiency helps maintaining discriminatory attitudes
against patients with AIDS and may decrease the quality of medical services to the group.
PMID: 2330511 [PubMed - indexed for MEDLINE]

J Appl Physiol 1989 Dec;67(6):2257-64
Rapid shallow breathing caused by pulmonary vascular congestion in cats.
Hatridge J, Haji A, Perez-Padilla JR, Remmers JE.
University of Texas Medical Branch, Galveston 77550.

The vasculature of one lung of unanesthetized spontaneously breathing decerebrate cats was
isolated and congested with blood. Such pulmonary vascular congestion (PVC) consistently
resulted in a shallow tachypnea associated with expiratory activation of the diaphragm and
thyroarytenoid muscles, signifying augmented expiratory braking. With progressive increases in
pulmonary vascular pressure, tachypnea and expiratory braking increased progressively and
ultimately obscured phasic activity in the diaphragm and thyroarytenoid. Thus the apnea caused
by PVC constitutes not an arrest of neural respiratory activity but rather a continuous activation
of thoracic inspiratory and laryngeal adductor muscles. When capsaicin, a neurotoxin that
activates nonmyelinated afferents, was injected into the pulmonary artery of the isolated lung, it
produced changes in timing and distribution of respiratory motor output that resembled those with
PVC but were more abrupt in onset. Capsaicin, applied perineurally to the cervical vagi,
preferentially blocked the conduction of nonmyelinated afferent fibers. This procedure, which
produced little degradation in Hering-Breuer reflexes, eliminated tachypnea and expiratory
braking caused by PVC or capsaicin injection. The results indicate that activation of pulmonary
vagal afferent fibers of C or A-delta category in unanesthetized cats reflexly modifies the
respiratory motor output in a way that resembles the human response to PVC or pulmonary
embolism. This is a brain stem reflex.
PMID: 2606831 [PubMed - indexed for MEDLINE]

Rev Invest Clin 1989 Oct-Dec;41(4):375-9
[Method for calculating the distribution of randomly expected scores in a
false-true-do not know-type of test].

[Article in Spanish]
Perez-Padilla JR, Viniegra Velazquez L.
Multiple choice tests have been used widely in the evaluation of knowledge. The lowest passing
limit is generally chosen arbitrarily. Better and more objective criteria may arise from analyzing the
distribution of correct and incorrect answers as expected by chance. In order to calculate the
distribution of correct answers and the difference between correct and incorrect answers (core)
we propose the use of a method based on a gaussian distribution. The distribution of scores
expected by chance is approximated by a gaussian distribution with a mean of zero and a
standard deviation SD = square root of n(pA + pE), and the distribution of the total number of
correct answers has a mean of npA and SD = square root of npApE, where n is the total number
of questions, and pA and pE are the probabilities of having a correct and an incorrect answer,
respectively. The formulae are applicable to questions type false/true/do not know and to the
more common type of one correct in five options. Once the chance distribution is known, it can
be compared with the distribution of scores or correct answers obtained, which can then be used
to separate people in two groups: those that answer the test as expected or worse than expected
by chance, and those that answer the test better than expected by chance. The first group should
not be passed. The passing of individuals in the second group can be decided by additional
criteria.
PMID: 2631171 [PubMed - indexed for MEDLINE]

Rev Invest Clin 1989 Jul-Sep;41(3):209-13
Rating of breathlessness at rest during acute asthma: correlation with
spirometry and usefulness of breath-holding time.
Perez-Padilla R, Cervantes D, Chapela R, Selman M.
We studied 13 patients with acute attacks of asthma to test the hypothesis that magnitude of
dyspnea at rest correlates well with spirometry and with breath-holding time. Dyspnea ("falta de
aire" in Spanish) was quantitated with a linear numerical scale from 0 to 10. We measured
breath-holding time, breathing frequency (f), and FEV1 and FVC both expressed as percent of
normal. Measurements were done on the patient's arrival and were repeated 3 to 6 times until
dyspnea at rest disappeared or was minimal. Dyspnea magnitude, f, and breath-holding time
correlated well with FEV1% and FVC% (r between 0.65 and 0.78), and better with changes in
FEV1% and FVC% with respect to initial values (delta FEV1 y delta FVC; r between 0.80 and
0.89). Breath-holding time and f changed in proportion to magnitude of dyspnea (r = -0.85 and
0.87 respectively). Regression equations were: dyspnea = 6.34 -0.16 (delta FEV1) r = 0.80,
and dyspnea = 7.82-0.105 (FEV1%) r = 0.62. Using multiple regression we improved
prediction of FEV1% with easily obtained variables (R = 0.76). These results suggest that: 1)
magnitude of dysnea, f, and breath-holding time correlate with severity of airflow obstruction in
acute asthma attacks associated with dyspnea at rest; and 2) breath-holding time varies inversely
with dyspnea magnitude when it is present at rest.

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