On the antioxidant properties of therapeutic drugs: quenching of singlet molecular oxygen by aminosalicylic acids.

The ability of the widely employed therapeutic drugs 4-aminosalicylic acid and 5-aminosalicylic acid to act as singlet molecular oxygen (O(2)((1)delta(g))) scavengers was investigated at pH 7 and pH 12. The isomer 3-aminosalicylic acid was also included in the study for comparative purposes. All three compounds quench photochemically generated O(2)((1)delta(g)) with rate constants in the range of 10(7)-10(8) x M(-1)s(-1), depending on the experimental conditions. No chemical reaction (oxidation of the aminosalicylic acids) was detected at the neutral pH, whereas at pH 12 both chemical and physical interactions with O(2)((1)delta(g)) operated. The physical process implies the de-activation of the oxidant species without destruction of the aminosalicylic acid. The quotients between the overall and reactive rate constants for O(2)((1)delta(g)) quenching at pH 12 (k(r)/k(t) ratios), which account for the actual effectiveness of photodegradation, were relatively low (0.22, 0.04, and 0.06 for 3-, 4- and 5-aminosalicylic acids, respectively). This indicates that the drugs, particularly the 4- and 5-amino derivatives, de-activate the excited oxygen species, at both pH values studied, mainly in a physical fashion, preventing its photodegradation and providing an antioxidative protection for possible photo-oxidizable biological targets in the surroundings.

Estudio de resistencia de Mycobacterium tuberculosis a distintos quimioterapicos / Resistance of Mycobacterium tuberculosis to different chemoterapeutic agents

Se efectuaron estudios de susceptibilidad de 62 cepas de M. tuberculosis aisladas a partir de esputos y/o lavados bronquiales. El método usado fue el de las proporciones de Canetti-Rist-Grosset. Las drogas y concentraciones empleadas en esta técnica fueron: INH (sioniácida) = 0,2 ug/ml; RIF (rifampicina) = 20 ug/ml; SM (estreptomicina) = 4 ug/ml; PAS (ácido para-aminosalicílico) = 5 ug/ml y EMB (etambutol) = 4 ug/ml. Las 62 cepas ensayadas (100%) se comportaron sensibles a PAS. De 22 cepas, 11 (50%) fueron resistentes a una sóla droga: INH; 7 (31,8%) a dos drogas; éstas fueron: INH y EMB 4 (18,2%); INH-RIF 2 (9,1%); INH-SM 1 (4,5%) y 4 cepas (18,2%) a tres drogas: INH-RIF-SM 2 (9,1%) y INH-EMB-SM 2 (9,1%). Los porcentajes de cepas de Mycobacterium tuberculosis resistentes a una o más drogas constituyen un importante índice para evaluar los programas de control de tuberculosis de una región. Se concluye, por lo tanto, la necesidad de la aplicación de programas de control eficases para la disminución paulatina de porcentajes de resistencia en nuestro medio

Estudio de resistencia de Mycobacterium tuberculosis a distintos quimioterapicos / Resistance of Mycobacterium tuberculosis to different chemoterapeutic agents

Se efectuaron estudios de susceptibilidad de 62 cepas de M. tuberculosis aisladas a partir de esputos y/o lavados bronquiales. El método usado fue el de las proporciones de Canetti-Rist-Grosset. Las drogas y concentraciones empleadas en esta técnica fueron: INH (sioniácida) = 0,2 ug/ml; RIF (rifampicina) = 20 ug/ml; SM (estreptomicina) = 4 ug/ml; PAS (ácido para-aminosalicílico) = 5 ug/ml y EMB (etambutol) = 4 ug/ml. Las 62 cepas ensayadas (100%) se comportaron sensibles a PAS. De 22 cepas, 11 (50%) fueron resistentes a una sóla droga: INH; 7 (31,8%) a dos drogas; éstas fueron: INH y EMB 4 (18,2%); INH-RIF 2 (9,1%); INH-SM 1 (4,5%) y 4 cepas (18,2%) a tres drogas: INH-RIF-SM 2 (9,1%) y INH-EMB-SM 2 (9,1%). Los porcentajes de cepas de Mycobacterium tuberculosis resistentes a una o más drogas constituyen un importante índice para evaluar los programas de control de tuberculosis de una región. Se concluye, por lo tanto, la necesidad de la aplicación de programas de control eficases para la disminución paulatina de porcentajes de resistencia en nuestro medio (AU)

Drug resistant tuberculosis in a large southern California hospital.

Rates of in vitro resistance to antituberculous drugs were examined for all patients hospitalized with active tuberculosis between January 1969 and December 1972, and between March 1975 and September 1976. During the former period, in 31.5 per cent of patients, tuberculosis was resistant to one or more drugs, and in 12.3 per cent of patients was resistant to 2 or more drugs. During the latter period, 35.5 per cent of patients had tuberculosis that was resistant to one or more drugs, and 19.6 per cent had tuberculosis resistant to 2 or more drugs. Resistance to isoniazid and ethambutol increased significantly, whereas resistance to para-aminosalicytic acid decreased. Age, national origin, and length of residence in the United States were not good predictors for the presence of in vitro resistance.