A tribute to professor Autar Singh Paintal (1925-2004).
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
V K Vijayan
Publications and source records attributed to V K Vijayan.
Evaluation of peptone glucose fluconazole agar as a selective medium for rapid and enhanced isolation of Aspergillus fumigatus from the respiratory tract of bronchopulmonary aspergillosis patients colonized by Candida albicans.
We have reported earlier that Aspergillus fumigatus is inhibited in vitro by Candida albicans which also interferes in its isolation from sputum experimentally seeded with predetermined graded inocula of the two fungi. It was further shown that this interference was neutralized by employing peptone glucose agar with incorporation of fluconazole which is more inhibitory to C. albicans than to A. fumigatus. This communication embodies the results of evaluation of peptone glucose fluconazole agar (PGFA) as a selective culture medium for rapid and enhanced isolation of A. fumigatus from sputum of patients clinically suspected of aspergillosis with C. albicans colonization in the respiratory tract. Of the 23 sputum specimens and one broncho-alveolar lavage collected from 15 suspected aspergillosis patients, A. fumigatus was isolated from all (100%) on PGFA as against only 19 specimens (79%) that proved to be positive on the control PGA medium (P<0.05). The greater efficacy of PGFA than that of PGA was further evident from the 2-fold higher A. fumigatus mean colony count (8.2+/-1.87) on the former medium than on the latter (3.7+/-1.00), and this difference was found to be statistically significant (P<0.05). Besides, A. fumigatus colonies were macroscopically recognizable within 2-3 days on PGFA at 28 degrees C in strong contrast to 5-7 days required on PGA. Based upon these observations, PGFA is recommended for wider application as a selective medium for rapid and enhanced recovery of A. fumigatus from sputum of patients clinically suspected of aspergillosis with C. albicans colonization in their respiratory tract.
Agar↗
Biological and epidemiological aspects of influenza virus H5N1 in context of India.
Since 1997, highly pathogenic avian influenza (HPAI) H5N1 virus crossed the species barriers from birds to humans and caused fatal disease, leading to great speculation about a possible influenza pandemic. This subtype is characterized by its pathogenicity in a large number of animal species and resistance to older class of antiviral drugs. At present, two out of three general conditions for the onset of pandemic have been met, emergence of new virus; and its ability to replicate in humans causing serious illness. Next influenza pandemic might be due to human to human transmission. This review addresses the biological and epidemiological aspects of influenza in context of India.
Animals↗
Involvement of nitric oxide (NO) in the regulation of stress susceptibility and adaptation in rats.
The present study evaluated the regulatory role of nitric oxide (NO) in stress susceptibility and adaptation in rats. Acute restraint stress (RS x1) reduced the number of entries and time spent in the open arms in the elevated plus maze (EPM) test and raised plasma corticosterone levels. RS (x1)-induced neurobehavioral suppression and raised corticosterone levels were attenuated by pretreatment with the NO precursor, L-arginine (500 and 1000 mg/kg)and unaffected or further aggravated by NO synthase inhibitor, L-NAME or 7-nitroindazole (10 and 50 mg/kg). Biochemical assay of plasma and brain homogenates showed that these RS - induced behavioral and neuroendocrinal changes were associated with lowered levels of plasma and brain total nitrates/nitrites (NOx). L-Arginine attenuated the RS-induced suppression of NOx levels in plasma and brain, whereas, the NO synthase inhibitors tended to produce reverse effects. In the experiments involving repeated stress i.e. RS (x5), exposure resulted in attenuation/reversal of (a) neurobehavioral suppression in the EPM test and (b) lowered brain NOx, that was seen after RS (x1). The RS (x5)-induced changes in EPM parameters and brain Nox were further potentiated after L-arginine pretreatment, whereas, the NO synthase inhibitors were less effective. Rats were screened as high and low emotional in the open-field test, and high emotional rats showed greater(a) behavioral suppression in the EPM, (b) corticosterone responses (c) brain NOx suppression, and (d) cold-restraint stress (CRS) induced gastric mucosal lesions as compared to their low emotional counterparts. L-Arginine pretreatment was more effective in modulating the above RS induced stress responses/markers in the high emotional group of rats. Our data suggest that NO plays a differential role during exposure to acute and repeated stress situations, and that the relationship between stress and emotionality status may be under the regulatory influence of NO.
Adaptation, Physiological↗
Possible role of free radicals in theophylline-induced seizures in mice.
Theophylline is a methylxanthine bronchodilator with a narrow therapeutic index and is prone to induce seizures, the mechanisms for which are not clearly defined. Free radicals have considerable neurotoxic potential and the present study evaluated the possible involvement of these bioactive moieties in aminophylline-induced seizures in mice. Aminophylline (50-250 mg/kg) induced convulsions and mortality in mice in a dose-dependent manner. The anti-oxidants, melatonin (25-100 mg/kg) and N-actylcysteine (100 and 200 mg/kg) attenuated aminophylline seizures and mortality. Similar antagonism of aminophylline seizures was also observed after pretreatments with nitric oxide (NO) synthase inhibitors, L-NAME (3 and 10 mg/kg) and 7-nitroindazole (10 and 30 mg/kg). Further, combined treatment with otherwise sub-effective doses of melatonin and L-NAME or 7-nitroindazole produced marked protective effects against these seizures. Aminophylline-induced seizures enhanced malondialdehyde (MDA) concentrations and NO metabolite (NOx) levels in the brain homogenates of mice, and these were attenuated by melatonin and L-NAME pretreatments. The results are suggestive of the possible involvement of free radicals (reactive oxygen and reactive nitrogen species) in the convulsiogenic effects of aminophylline.
Aminophylline↗
Pharmacological studies on mechanisms of aminophylline-induced seizures in rats.
In the present study, the possible role of free radicals in aminophylline-induced seizures was evaluated in albino rats. Aminophylline (theophylline in ethylene diamine; 50 - 300 mg/kg) induced convulsions in rats in a dose-dependent manner, and both incidence of seizure and mortality were maximum at 300 mg/kg. Conventional anti-epileptics, diphenylhydantoin and dizocilpine, as well as adenosine agonists were ineffective in antagonizing these seizures. On the other hand, phosphodiesterase inhibitors, pentoxyphylline and rolipram, showed insignificant seizurogenic effects. Pretreatment with antioxidants (ascorbic acid, alpha-tocopherol, and melatonin) showed differential attenuating effects on aminophylline seizures and lethality. Further, prior administration of 1-buthionine sulfoxamine (BSO, glutathione depletor) and triethyltetramine (TETA, superoxide dismutase inhibitor), precipitated seizures and enhanced lethality in response to subthreshold doses of aminophylline. The present results suggested of the possible involvement of oxidative stress during aminophylline-induced seizures.
Aminophylline↗
Pharmacological and biochemical studies on the possible role of nitric oxide in stress adaptation in rats.
The involvement of nitric oxide (NO) in stress adaptation was evaluated in rats using the elevated plus maze test. Repeated restraint stress RS(x 5) for 5 days resulted in an increase in the percentage number of entries and percentage time spent when compared to a single restraint stress RS(x 1) exposure. In the repeated RS treatment groups, the nitric oxide donor, L-arginine (500 and 1000 mg/kg, i.p.) slightly increased the elevated plus maze test parameters when compared to the corresponding vehicle-treated group. The nitric oxide synthase (NOS) inhibitors, N-nitro-L-arginine methyl ester (L-NAME, 10 and 50 mg/kg, i.p.) and 7-nitroindazole (10 and 50 mg/kg, i.p.) produced differential responses in both the parameters with L-NAME exhibiting greater reduction in open arm entries and open arm time, whereas 7-nitroindazole produced only small differences in both the elevated plus maze parameters. Biochemical data showed that repeated restraint stress resulted in higher levels of brain nitrates and nitrites (NOx) as compared to that of single restraint stress exposure. Further, in L-arginine (1000 mg/kg, i.p.)-treated rats, brain NOx was lowest in the single restraint stress group, followed by repeated restraint stress and (no restraint stress) controls. The results are suggestive of the role of nitric oxide in stress adaptation and this may be due to the effects of restraint stress on brain NOS activity.
Adaptation, Physiological↗
Pharmacotherapy of tobacco dependence.
Smoking cessation activities and support for its implementation should be integrated into the health care system. The outcome of smoking cessation has improved with the availability of proper behavior approaches and medications. Incorporating these guidelines into daily clinical practice ensures that health care providers provide the opportunity for patients to quit smoking. The best hope of improved treatment comes from combining existing and new pharmacotherapies with effective behavioral therapy.
Adrenergic alpha-Agonists↗
Modulation of stress-induced neurobehavioral changes by nitric oxide in rats.
The involvement of nitric oxide (NO) in stress-induced neurobehavioral changes in rats was evaluated using the elevated plus maze and open field tests. Restraint stress (1 h) reduced both the number of entries and time spent in open arms, with both expressed as percent of controls (no restraint stress), and these changes were reversed with diazepam (1 mg/kg) and the NO precursor, L-arginine (500 and 1000 mg/kg) pretreatment. The nitric oxide synthase inhibitor, N-nitro-L-arginine methyl ester (L-NAME) (50 mg/kg), aggravated restraint stress effects in the elevated plus maze test, whereas the lower dose (10 mg/kg) of the drug attenuated the same. In the open field test, the restraint stress-induced (a) increased entry latency and (b) decreased ambulation and rearing were reversed by diazepam and L-arginine and L-NAME (10 mg/kg), whereas L-NAME (50 mg/kg) aggravated restraint stress effects. The neuronal nitric oxide synthase inhibitor, 7-nitroindazole (10 and 50 mg/kg), did not influence these restraint stress-induced behavioral changes to any significant extent. Biochemical data showed that L-NAME (10 and 50 mg/kg.) induced opposite effects on the total brain nitrate/nitrite content during restraint stress. The results indicate a possible involvement of NO in stress-induced neurobehavioral effects.
Animals↗
Reduced exercise capacity in non-cystic fibrosis bronchiectasis.
OBJECTIVE: Bronchiectasis not due to cystic fibrosis is usually a consequence of severe bacterial or tuberculous infection of the lungs, which is commonly seen in children in developing countries. Our aim was to study its functional sequelae and affect on work capacity in children. METHODS: Seventeen children (7-17 years of age) with clinical and radiological evidence of bronchiectasis of one or both lungs were studied at the Cardiopulmonary Unit of the Tuberculosis Research Centre. Pulmonary function tests including spirometry and lung volume measurements were performed. Incremental exercise stress test was done on a treadmill, and ventilatory and cardiac parameters were monitored. Control values were taken from a previous study. RESULTS: Children with bronchiectasis had lower forced vital capacity (FVC) (1.1 + 0.4 L versus 1.5 + 0.4 L, p = 0.003) and FEV1 (0.95 +/- 0.2 L versus 1.4 +/- 0.3 L, p < 0.002) compared to age- and sex-matched healthy controls. The patient group had significantly higher residual lung volumes (0.7 +/- 0.3 L versus 0.4 + 0.1 L, p < 0.02). At maximal exercise, they had lower aerobic capacity (28 +/- 6 ml/min/kg versus 38 +/- 5 ml/min/kg, p < 0.0001) and maximal ventilation (24 +/- 8 L/min versus 39 +/- 10 L/min, p < 0.001). At maximal exercise, while none of the controls desaturated, oxygen saturation fell below 88% in eight of 17 patients. CONCLUSION: The findings show that children and adolescents with non-cystic fibrosis bronchiectasis have abnormal pulmonary function and reduced exercise capacity. This is likely to interfere with their life as well as future work capacity. Efforts should be made to minimize lung damage in childhood by ensuring early diagnosis and instituting appropriate treatment of respiratory infections.
Adolescent↗
Chronic Klebsiella pneumonia in an immunocompetent host.
A 55 years immunocompetent male was evaluated for chronic pulmonary disease of over 12-month duration for which he had twice been prescribed anti-tubercular therapy. Investigations led to the diagnosis of chronic Klebsiella pneumonia, which is rarely encountered in immunocompetent hosts in the antibiotic era.
Chronic Disease↗
Expression of bronchodilator response: comparison of four indices.
Several indices have been suggested to express the bronchodilator response but there is no agreement on what is the ideal expression. The forced expiratory volume in I s (FEV1) was measured in 190 patients of bronchial asthma before and after inhalation of 200 micrograms salbutamol. Four different indices of bronchodilator response were calculated. The change in FEV1 was expressed as absolute value (delta FEV1), as a percentage of initial FEV1 (delta FEV1% initial), as a percentage of the predicted normal value (delta FEV1% predicted) and as a percentage of maximum achievable reversibility, i.e. the difference between predicted and initial values (delta FEV1% [predicted-initial]). A significant negative correlation was observed between delta FEV1 initial and initial FEV1% predicted (r = -0.33, P < 0.0001) but not delta FEV1 and initial FEV1% predicted, or between delta FEV1% predicted and initial FEV1% predicted. The values of delta FEV1% [predicted-initial] tended to reach towards infinity as the initial FEV1% predicted approached 100%. delta FEV1% predicted had similar sensitivity but greater specificity than delta FEV1% initial in detecting a true bronchodilator response. It was concluded that being dependent on the initial value, delta FEV1% initial was not an appropriate method to express the bronchodilator response. Although all other methods had limitations, delta FEV1 and delta FEV1% predicted appeared to be better indices.
Adult↗
Smoking and tuberculosis: an association overlooked.
OBJECTIVES: This article discusses the role of smoking as a risk factor for tuberculosis. A review of the evidence that has been documented is presented. DATA SOURCES: Relevant articles in the medical literature derived from searching the Medline database (1966 to present) with key terms 'smoking' and 'tuberculosis'. The bibliographies of all papers thus located were searched for further relevant articles. RESULTS: On searching the database, a total of 12 studies were found. A search of the bibliographies yielded four more articles. Sixteen studies published between 1956 to the present were included in this review. The evidence suggests that smoking could be considered as an important risk factor for the development of tuberculosis. Not only does active smoking appear to heighten the chances of contracting pulmonary tuberculosis, smokers also seem to be at an increased risk for extrapulmonary tuberculosis. Exposure to environmental tobacco smoke in children seems to enhance the hazards of acquiring tuberculosis. Increased tuberculin reactivity, in a dose-dependent manner, was recorded in smokers as compared to non-smokers. CONCLUSIONS: Although an association between smoking and tuberculosis appears evident, prospective studies would help to confirm the evidence and to highlight this noxious association. Nevertheless, smoking should be considered as an important risk factor for tuberculosis.
Epidemiologic Studies↗
Disseminated tuberculosis.
Even though effective chemotherapeutic regimens are available for treatment of tuberculosis (TB), disseminated tuberculosis (DT) continues to be a challenge to physicians. DT represents the unchecked haematogenous dissemination of Mycobacterium tuberculosis. It has been reported that 1.3% of all TB cases are classified as DT. Patients with DT present with a febrile illness of 2 to 4 months' duration. Organomegaly affecting liver, spleen and lymph nodes can be seen in DT. The radiological findings of DT associated with HIV infection are similar to those seen in HIV-seronegative patients. The value of high resolution computed tomography in DT is to demonstrate miliary pattern when chest radiographic findings are atypical or even normal. DT patients may have a mild normochromic anaemia with a normal white blood cell count. Leukaemoid reaction can occur in DT, but pancytopenia is rare. Pulmonary function studies show a mild restrictive ventilatory defect with diffusion defect in cases of pulmonary miliary tuberculosis. Treatment of DT is same as that for pulmonary tuberculosis. Replacement treatment with corticosteroids should be given in tuberculosis patients with adrenal insufficiency. The overall mortality from DT is nearly 20%.
AIDS-Related Opportunistic Infections↗
Aerobic capacity and cardiopulmonary response to exercise in healthy south Indian children.
OBJECTIVE: To examine the cardiorespiratory response to exercise in healthy South Indian school children. DESIGN: Prospective study. SETTING: Cardiopulmonary Medicine Unit, Tuberculosis Research Center, Madras. SUBJECTS: Data was obtained on 47 girls and 48 boys in the age group 7 to 14 years. INTERVENTION: The children performed a graded maximal exercise stress test on a computerized treadmill system. RESULTS: Maximum oxygen consumption (VO2max) increased significantly at 11 years of age in both sexes but while boys showed a progressive increase beyond 11 years, girls did not. When corrected for weight, only boys at 14 years had a significant increase in VO2max/kg. Boys had higher values of VO2max/kg than girls at all ages. Minute ventilation and oxygen pulse values also increased in both sexes at 11 to 12 years. The VO2max of South Indian children was lower than the predicted values available for North American children when prediction equations based on height were used. However, when regression equations based on weight were used, the predicted values for North American and South Indian boys were similar, though values for the Indian girls were still low. CONCLUSIONS: Nutritional and sociocultural factors may play a role in determining VO2max of children from different populations, rather than ethnic differences alone.
Adolescent↗
Relationship between lung inflammation, changes in lung function and severity of exposure in victims of the Bhopal tragedy.
The world's worst chemical industrial disaster, which occurred at Bhopal on 2-3 December, 1984, resulted in considerable respiratory morbidity in the exposed population. Therefore, a study was planned to evaluate the relationship between lower respiratory tract inflammation, lung function and severity of exposure. Sixty patients exposed to methyl isocyanate and presenting with respiratory symptoms were studied using bronchoalveolar lavage (BAL) 1-7 yrs after the accident. Pulmonary function tests included forced vital capacity (FVC) and forced expiratory volume in one second (FEV1). An index of severity of exposure was derived retrospectively on the basis of the acute symptoms in the victims themselves or the occurrence of death among their family members. Total lung inflammatory cells (p < 0.01) and absolute numbers of macrophages (p = 0.01) and lymphocytes (p < 0.05) increased as severity of exposure increased. FEV1/FVC % (p = 0.05) was also significantly lower as severity of exposure increased. Moderately exposed subjects had significantly lower FEV1/FVC % (p < 0.05) compared to those mildly exposed. In nonsmokers, BAL neutrophils, both percentage and absolute numbers, showed significant negative correlations with FEV1 % predicted (rs = -0.350, p < 0.05; and rs = -0.374, p < 0.01, respectively). Neutrophil percentage was negatively correlated with FEV1/FVC % (rs = -0.378; p < 0.01). Absolute lymphocytes had significant negative correlations with FVC % pred (rs = -0.318; p < 0.05). Macrophages had significant positive correlations with FVC % pred (rs = 0.322; p < 0.05) and FEV1 % pred (rs = 0.433; p < 0.01). Radiographic abnormalities (International Labour Organization (ILO) classification) were associated with decline in FEV1 % pred (p < 0.05). This study suggests that pulmonary function abnormalities occur in gas-exposed subjects as a consequence of an abnormal accumulation of lung inflammatory cells (lymphocytes and neutrophils), and that the intensity of lung inflammation and reduction in pulmonary function are greater in severely exposed subjects. As it has been observed that decline in pulmonary function is associated with radiographic abnormalities, there is a suggestion that injury following toxic gas exposure can lead to irreversible lung damage.
Accidents, Occupational↗
Chronic lung inflammation in victims of toxic gas leak at Bhopal.
Bronchoalveolar lavage (BAL) studies in 20 patients at Bhopal, 1.3 +/- 0.4 yr and 2.7 +/- 0.6 yr after toxic gas exposure had revealed that the lower respiratory tract inflammation had progressed from initial macrophage alveolitis to macrophage-neutrophilic alveolitis. The interval between the two lavages was 1.4 +/- 0.6 yr. BAL studies in a new group of 24 patients 5.1 +/- 1.0 yr after exposure had confirmed chronic inflammation of the lower respiratory tract as evidenced by macrophage-neutrophilic alveolitis in these subjects as well. Clinical, radiographic and pulmonary function abnormalities were persistent in a proportion of subjects in both groups. Fibronectin (FN) levels were estimated in BAL fluid in 41 patients. Elevated FN levels were seen in 12 (29.3%) subjects and nine of these 12 had radiographic abnormalities. Severely exposed subjects (n = 30) had significantly higher BAL fibronectin levels compared to normal subjects and mild/moderately exposed subjects. Repeat FN estimations in BAL samples from 10 patients had revealed that five had abnormally high FN including three who had high FN on both occasions. The number of patients showing abnormal decline in pulmonary function was higher in patients with elevated FN than in patients with normal FN. Thus, persisting clinical, roentgenographic and ventilatory abnormalities, as well as macrophage-neutrophilic alveolitis along with abnormally elevated FN levels in a proportion of subjects, suggest the possibility that lung fibrosis can occur in subjects exposed to toxic gas at Bhopal.
Accidents, Occupational↗
Value of bronchoalveolar lavage and gastric lavage in the diagnosis of pulmonary tuberculosis in children.
OBJECTIVE: The aim of our study was to find out if bronchoalveolar lavage (BAL) would be better than gastric lavage for the isolation of Mycobacterium tuberculosis from pediatric patients with suspected pulmonary tuberculosis. DESIGN: 50 children with suspected pulmonary tuberculosis at a mean age of 5.1 years (range 7 months to 12 years) were studied. Early morning gastric lavage was collected. Flexible bronchoscopy and bronchoalveolar lavage was performed under local anaesthesia after obtaining informed consent from the parents. The BAL fluid and gastric lavage specimens were subjected to smear examination for acid-fast bacilli (AFB) and culture for mycobacteria using established methods. RESULTS: Of the 50 cases, M. tuberculosis was grown in 6 BAL samples (12%) and 16 gastric lavage samples (32%) making a total of 17 culture proven cases (34%). Out of the 6 BAL positive cases, gastric lavage was also positive in 5 cases. CONCLUSION: We conclude that gastric lavage is better than BAL for bacteriologic confirmation of pulmonary tuberculosis in children. The overall bacteriologic yield combining both procedures was 34% while gastric lavage alone was positive in 32% of the cases.
Bronchoalveolar Lavage Fluid↗