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Biomedical subjects

R Prabhakar

Publications and source records attributed to R Prabhakar.

At least 73 records · Page 4Linked to original sources
PubMed1992

Susceptibility of south Indian strains of Mycobacterium tuberculosis to tuberactinomycin.

A total of 114 strains of Mycobacterium tuberculosis isolated from sputum samples of 114 patients of pulmonary tuberculosis in south India, were coded and tested for their in vitro susceptibility to tuberactinomycin (Tum) incorporated in Lowenstein-Jensen (LJ) medium. Of these strains, 95 (83.3%) and 15 (13.2%) were susceptible to Tum at 25 and 50 mg/l respectively. Only 4 (3.5%) strains were inhibited at 100 mg/l or more. Of the 37 drug sensitive strains, 2 (5.4%) were not susceptible to Tum at 25 mg/l compared to 17 (22.1%) of 77 strains-resistant to one or more of antituberculosis drugs (P less than 0.02). The drug susceptibility pattern of the strains revealed that there was no significant association of resistance between Tum and streptomycin or rifampicin or ethambutol or ethionamide or isoniazid. However, 15 (53.6%) of 28 kanamycin (K) resistant strains were not susceptible to Tum at 25 mg/l. This cross resistance between Tum and K was further studied in 24 and 15 K sensitive and resistant strains respectively, by correlating their proportion resistance at 16 mg/l and it was found to have a significant positive correlation (r = 0.55; P less than 0.01).

Drug Resistance, Microbial↗
PubMed1991

Association of pulmonary tuberculosis and HLA in south India.

In 204 patients with smear-positive pulmonary tuberculosis HLA-A10, B8 and DR2 were more frequently found than in 404 control subjects (p = 0.01); the greatest attributable risk (0.29) was associated with HLA-DR2. The radiographic extent of disease was also associated with HLA-DR2 (p = 0.0001). In 152 patients with smear-negative pulmonary tuberculosis, the frequencies of HLA-A10 and B8, but not DR2, were greater in the control subjects (p = 0.001 and 0.01 respectively). HLA-DR2 may be involved in the pathogenesis of advanced pulmonary tuberculosis. Study of endogamous, genetically disparate populations (caste) revealed other HLA associations (A3, B12 and DR4) unique to them, suggesting that genes linked with the HLA complex might also be significant in the pathogenesis of tuberculosis.

Adult↗
PubMed1991

Tropical eosinophilia: clinical and physiological response to diethylcarbamazine.

Fifty patients with tropical eosinophilia were studied clinically and physiologically, before and after a standard 3-week course of diethylcarbamazine. Before treatment the main physiological abnormality was a reduction in the carbon monoxide transfer factor. One month after the start of treatment most patients had shown a marked symptomatic improvement, but peripheral blood eosinophilia persisted in 52%, radiographic abnormalities in 44%, cough in 22% and chest signs in 8%. Significant improvement was noted in almost all aspects of lung function including blood gases, but the mean values for forced expiratory volume in one second, forced vital capacity, transfer factor and transfer coefficient continued to be significantly lower than predicted values. This study demonstrates the incomplete reversal of clinical, haematological, radiological and physiological changes in tropical eosinophilia one month after starting a 3-week course of diethylcarbamazine.

Adolescent↗
PubMed1991

Effect of diethylcarbamazine on the alveolitis of tropical eosinophilia.

Bronchoalveolar lavage studies in 33 patients with acute untreated tropical eosinophilia have demonstrated intense eosinophilic alveolitis. Following treatment with a standard 3-week course of diethylcarbamazine, there was a significant fall in lung eosinophils (p less than 0.001). However, a mild alveolitis characterised by hypercellular lavage fluid due to a significant increase in absolute alveolar macrophages (p less than 0.001) and due to an increase in both the absolute number (p less than 0.01) and percentage of eosinophils (p = 0.02) was persisting at 1 month despite treatment. Long-term follow-up is essential to know the fate of alveolitis.

Acute Disease↗
PubMed1991

Prevalence study of tuberculous infection over fifteen years, in a rural population in Chingleput district (south India).

As in the earlier BCG trial against tuberculosis conducted in Chingleput district in south India (in 1969), the entire study population was tuberculin tested (Survey I), a study was undertaken subsequently to see whether in this population there was any change in the tuberculosis situation in terms of prevalence of infection in children. For this purpose, in two of the panchayat unions, in a random sample of panchayats, tuberculin testing was repeated twice at an interval of 10 yr (Survey II) and 15 yr (Survey III) after the initial testing in children aged 1-9 yr. High coverages were obtained for tuberculin testing and reading. Data from 8,703 and 9,709 children at Surveys I and II respectively was used for comparing the prevalence of infection over a period of 10 yr and from 4,808, 4,965 and 4,889 children at Surveys I, II and III respectively for comparing the prevalence of infection over a period of 15 yr. The results showed that although the prevalence of infection varied in the two panchayat unions, within each panchayat union it did not differ significantly at the three surveys. The overall prevalence of infection at the three surveys was 9.0, 10.2 and 9.1 per cent respectively. The average annual risk of tuberculous infection was estimated to be 1.7, 1.9 and 1.7 per cent at the three surveys respectively. Thus, the results clearly showed that, over a period of 15 yr, there was no change in the tuberculosis situation, in terms of prevalence of infection, in the study population.

Adolescent↗
PubMed1990

A controlled trial of ivermectin and diethylcarbamazine in lymphatic filariasis.

Ivermectin is a new antifilarial drug that can be given in a single oral dose. To compare the efficacy and side effects of ivermectin with those of diethylcarbamazine, the standard antifilarial treatment, we conducted a randomized, double-blind trial in 40 South Indian men with lymphatic filariasis caused by Wuchereria bancrofti. Patients were randomly assigned to one of three treatments: a single low dose of ivermectin (mean [+/- SE], 21.3 +/- 0.7 micrograms per kilogram of body weight; n = 13) followed by placebo for 12 days; a single high dose of ivermectin (mean, 126.2 +/- 3.7 micrograms per kilogram; n = 13) followed by placebo for 12 days; or diethylcarbamazine for 13 days (6 mg per kilogram per day for 12 days preceded by 3 mg per kilogram for 1 day; n = 14). Eleven patients were initially assigned to receive placebo and after five days were reassigned to one of the three treatment groups. At day 12 there was complete clearance of microfilariae from the blood in all 26 men who took ivermectin and in 11 of the 14 men who took diethylcarbamazine. At six months the numbers of detectable microfilariae (as a percentage of the pretreatment values) were 18.3 percent after low-dose ivermectin and 19.5 percent after high-dose ivermectin, as compared with 6.0 percent after diethylcarbamazine (P less than 0.05). The side effects were confined to the first five days and were similar in the three treatment groups. We conclude that in lymphatic filariasis, the clinical response to a single dose of ivermectin compares favorably with that after the standard 12-day course of diethylcarbamazine. Given the practical advantages of single-dose administration, ivermectin should become a useful medication for the control of bancroftian filariasis.

Adult↗
PubMed1990

Adrenocortical function in patients with pulmonary tuberculosis.

Adrenocortical function was studied in patients with pulmonary tuberculosis and the findings compared with those in healthy subjects. Plasma cortisol levels in newly diagnosed patients were appreciably higher than in the healthy subjects (P less than 0.001). A normal (positive) response to ACTH (tetracosactrin) stimulation was observed in 35 (97%) of 36 healthy subjects, 15 (56%) of 27 newly diagnosed patients with tuberculosis and 5 (42%) of 12 chronic cases (i.e. those who had had the disease for more than 3 years); the difference between the healthy subjects and the two groups of tuberculosis patients was highly significant (P less than 0.001). Dexamethasone caused an appreciable decrease in the plasma cortisol levels of tuberculosis patients. Considering the diurnal variation of cortisol secretion, there was a steady decline in the cortisol levels between 08:00 and 20:00 in the healthy subjects (P = 0.02); in the tuberculosis patients, however, there was a decrease up to 16:00 followed by a significant increase (P = 0.05), and the mean value at 20:00 was similar to that at 08:00.

Adrenal Cortex↗
PubMed1990

Pulmonary function in healthy young adult Indians in Madras.

Forced vital capacity, forced expiratory volume in one second, functional residual capacity, residual volume, total lung capacity, and single breath diffusing capacity measurements (effective alveolar volume, carbon monoxide transfer factor, and transfer coefficient) were measured in 247 young healthy adults (130 male, 117 female) aged 15-40 years living in Madras. Subjects were of Dravidian stock, living at sea level with rice as their staple diet. Regression equations were derived for men and women for predicting normal pulmonary function for young adults in South India. The values were similar to those reported for subjects from Western India and lower than those reported for North Indians and caucasians.

Adolescent↗
PubMed1990

Persistent lower respiratory tract inflammation associated with interstitial lung disease in patients with tropical pulmonary eosinophilia following conventional treatment with diethylcarbamazine.

Tropical pulmonary eosinophilia (TPE) presents as an acute syndrome with dyspnea, fluffy infiltrates, and rounded opacities on the chest radiograph, reduced lung function, marked eosinophilia in the blood and lower respiratory tract, and high titers of specific IgE and IgG antifilarial antibodies. The standard therapy for TPE is a 3-wk course of diethylcarbamazine (DEC) following which there is almost always a marked improvement in all parameters. However, clinical observations suggest that the disease can persist despite DEC therapy and lead to chronic dyspnea with restrictive lung impairment. To evaluate the concept that DEC therapy is not completely "curative" for TPE, but rather leaves most individuals with a mild, chronic form of TPE defined by persistent inflammation of the lower respiratory tract, we evaluated 23 individuals an average of 12 +/- 2 months following a standard 3-wk course of diethylcarbamazine for acute TPE. In the majority there were mild, persistent symptoms referrable to the lung, chest X-ray abnormalities, blood eosinophilia, and elevated serum IgE and filarial specific IgG. On the average, lung function was consistent with the presence of chronic, mild interstitial lung disease. When the inflammatory cells from the lower respiratory tract were examined, there was a persistent eosinophilic alveolitis (TPE/post-DEC 1769 +/- 376 eosinophils/microliters epithelial lining fluid; normal subjects 256 +/- 38, p less than 0.02). Evaluation of the lower respiratory tract inflammatory cells recovered from the TPE/post-DEC-treated individuals demonstrated spontaneous release of exaggerated amounts of O2-. and H2O2 compared to normal subjects (p less than 0.05, both comparisons).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1990

Pulmonary membrane diffusing capacity and capillary blood volume in tropical eosinophilia.

Pulmonary membrane diffusing capacity (Dm) and pulmonary capillary blood volume (Vc) measurements were carried out in 21 patients with untreated tropical eosinophilia and 21 healthy controls matched for age, sex, height, and smoking habit. The mean single breath transfer factor (Dco) and the mean membrane diffusing capacity were significantly lower (p less than 0.001) in patients with tropical eosinophilia compared with control subjects. However, the mean capillary blood volume was not significantly different (p greater than 0.2). The positive correlations between Dm and transfer factor (r = 0.825), between Dm and effective alveolar volume (VA) (r = 0.721), and between Dco and VA (r = 0.774) were also highly significant (p less than 0.001) in study patients prior to treatment. These data suggest that reduction in single breath transfer factor in untreated tropical eosinophilia may be due to a reduction in membrane diffusing capacity, which in turn may be due to a reduction in area of membrane available for diffusion, as evidenced by the significantly reduced VA (p less than 0.001) in these patients. Since pulmonary capillary blood volume was normal, the pulmonary perfusion was within normal limits. Following three weeks of treatment with diethylcarbamazine citrate, although there was a significant rise in single breath transfer factor (p less than 0.001) and membrane diffusing capacity (p less than 0.05), both Dco (p less than 0.01) and Dm (p less than 0.01) continued to be significantly lower than those of control subjects. However, pulmonary capillary blood volume did not show any change (p greater than 0.2).

Adult↗
PubMed1990

Controlled clinical trial of two multidrug regimens with and without rifampin in highly bacilliferous BL/LL south Indian patients: a five-year report.

A controlled clinical trial of two multidrug regimens in multibacillary lepromatous and near-lepromatous patients with a bacterial index (BI) of 2.5 or more was conducted. Patients were randomly allocated to either a two-drug regimen of dapsone plus clofazimine for 60 months or a four-drug regimen of rifampin, isoniazid, dapsone, and clofazimine for the first 3 months and clofazimine plus dapsone for the next 57 months. There was no difference between the rifampin and nonrifampin regimens with respect to the clinical improvement or bacteriological status of the patients at 60 months. Reactive states and neuritis were observed to be equal in the two patient groups.

Adolescent↗
PubMed1989

Treatment of pulmonary tuberculosis with short course chemotherapy in south India--5-year follow up.

A controlled clinical trial of three short-course chemotherapy regimens was undertaken in patients with newly diagnosed bacteriologically positive pulmonary tuberculosis. The patients were randomly allocated to receive one of three regimens: rifampicin, streptomycin, isoniazid and pyrazinamide daily for 2 months, followed by streptomycin, isoniazid and pyrazinamide twice weekly for 3 months (R/5) or for 5 months (R/7), or the same regimen as R/7 but without rifampicin (Z/7). A bacteriological relapse requiring retreatment occurred by 5 years in 7.1% of 126 R/5, 4.0% of 124 R/7 and 6.7% of 253 Z/7 patients with organisms initially sensitive to streptomycin and isoniazid; none of these differences is statistically significant. Of the 31 relapses, 16 occurred within 2 years of the completion of chemotherapy and the remaining 15 between 2 and 5 years. Among 65 patients with initial drug resistance to streptomycin or isoniazid or both, there were six bacteriological relapses requiring retreatment.

Adolescent↗
PubMed1989

Long-term status of children treated for tuberculous meningitis in south India.

This report gives the findings of long-term follow-up (4 1/2-8 years) of 119 children who recovered from tuberculous meningitis. Of these, 17 patients died (10 due to severe tuberculous meningitis sequelae and 7 due to non-tuberculous causes) and 2 could not be traced. Of the remaining 100 patients for whom information was available, 47 (47%) made a complete recovery, while 53 (53%) had neurological sequelae--2 (2%) had severe, 39 (39%) moderate and 12 (12%) mild sequelae. There were no relapses during the 4 1/2-8 year period, indicating that regular treatment for 12 months may be adequate.

Antitubercular Agents↗
PubMed1988

Ivermectin for the treatment of Wuchereria bancrofti filariasis. Efficacy and adverse reactions.

Ivermectin treatment was evaluated for efficacy and side effects in 40 patients in South India who had microfilaremia and bancroftian filariasis. Ivermectin was administered once orally at four dose levels (range, 25 to 200 micrograms/kg), and at each it was found to be completely effective in clearing blood microfilariae within five to 12 days. In most patients, microfilariae reappeared by three months; by six months the levels averaged 14% to 32% of pretreatment values in the four study groups, and all groups showed equivalent efficacy. Detailed monitoring identified some side effects in almost all patients: usually fever, headache, light-headedness, myalgia, sore throat, or cough that occurred most prominently 18 to 36 hours after treatment. These were most frequent and severe in patients with the greatest microfilaremia, but only when treated with the two higher doses of ivermectin (100 and 200 micrograms/kg). The low-dose (25 micrograms/kg) ivermectin group, despite equivalent efficacy in parasite killing, had clinical reaction scores that were minimal and that were not correlated with parasitemia. Since efficacy and side effects of ivermectin therapy compare favorably with those reported for treatment with the standard antifilarial drug diethylcarbamazine citrate, the major advantage of single-oral-dose administration makes ivermectin the best candidate to replace diethylcarbamazine as the treatment of choice for bancroftian filariasis.

Adult↗
PubMed1988

A double-blind controlled clinical trial to assess the role of anti-histamines in the treatment of multi-bacillary leprosy.

A double blind controlled clinical trial to assess the role of anti-histamines as a supplement in the treatment of leprosy was conducted in multi-bacillary cases of leprosy. In all, 120 patients with lepromatous or borderline leprosy were randomly allocated to a regimen of clofazimine and dapsone for 12 months with or without a supplement of pheniramine maleate for the first 3 months. During the 12-month period, 92% of the patients who received the supplement and 86% of the patients who had not received it had moderate or marked clinical improvement. The BI values decreased from 4.1 to 3.4 and 4.2 to 3.3, respectively. The results over the 12-month period showed that the addition of the antihistamine had not enhanced the efficacy of the regimen as evidenced by clinical and bacteriological findings.

Adolescent↗