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Biomedical subjects

S Radhakrishna

Publications and source records attributed to S Radhakrishna.

At least 55 records · Page 3Linked to original sources
PubMed1982

Study of a policy to minimise the prescription of medicaments at first attendance at chest clinics.

In chest clinics in Madras, south India, medicaments are prescribed to many patients at the first clinic attendance, whether necessary on medical grounds or not, in the belief that this practice will increase the likelihood of the patients subsequently reattending the clinic. This study of 2608 patients in four chest clinics showed that the proportion prescribed medicaments ranged from 50% to 75%. Subsequently, a modified policy of prescribing medicaments only when they were medically essential was investigated on 956 patients in the largest of these clinics. The policy was found to be practicable, and it did not have any adverse consequences such as an increased rate of default or an unacceptable level of patient dissatisfaction. The advantages of the new policy are savings in money, man-power, and time and the potential for a reduction in the incidence of side-effects.

Adult↗
PubMed1982

The development of clinical tuberculosis following infection with tubercle bacilli. 1. A theoretical model for the development of clinical tuberculosis following infection, linking from data on the risk of tuberculous infection and the incidence of clinical tuberculosis in the Netherlands.

Information on the risk of tuberculous infection in the Netherlands has been linked with information on the incidence of tuberculosis, in an attempt to estimate the risks of developing the disease following infection or reinfection. It was postulated that: (a) those with a recent primary infection had a characteristic risk of developing progressive primary tuberculosis; (b) those with a distant (i.e. not recent) primary infection and a recent reinfection had a characteristic risk of developing exogenous tuberculosis; and (c) those with a distant primary infection but no recent reinfection had a characteristic risk of developing endogenous tuberculosis. The information on the risk of tuberculous infection was used to estimate the size of the population in each of these infection classes for different age-groups and calendar years in the Netherlands. Using multiple regression to link these population figures with the information on tuberculosis incidence in the same age group and calendar year, it was possible to estimate the above risks of developing tuberculosis. For Netherlands males aged 15-69 years during the period 1951-70 the three risks of developing pulmonary tuberculosis were estimated to be: (a) 5.06 per cent annually (for 5 years) following primary infection; (b) 1.91 per cent annually (for 5 years) following reinfection; (c) 0.0253 per cent annually, after the first 5 years following primary infection, in the absence of reinfection. The corresponding (and significantly different) estimated annual risks of development of pulmonary tuberculosis for females were 5.85, 1.10 and 0.0020 per cent respectively. From these risks, it may be estimated that the degree of protection conferred by a distant primary infection, against pulmonary tuberculosis arising from a recent reinfection, was 63 per cent for males and 81 per cent for females. The estimated relative proportions of cases of progressive primary, exogenous and endogenous tuberculosis varied considerably with age and calendar year. Progressive primary tuberculosis was dominant at the younger ages, exogenous and endogenous tuberculosis at older ages. At these older ages, the great majority of cases in the Netherlands in the early 1950s appeared to be exogenous in origin, but by 1970, with the decrease in the risk of infection, the exogenous contribution had dwindled substantially, especially among males.

Adolescent↗
PubMed1981

A randomised study of two policies for managing default in out-patients collecting supplies of drugs for pulmonary tuberculosis in a large city in South India.

A randomized controlled study was undertaken to compare 2 policies of default management in out-patients with smear-negative pulmonary tuberculosis attending a large chest clinic in Madras city. All the patients were due to collect monthly supplies of drugs for a year, for daily self-administration at home. In the routine (R) policy, if a patient failed to collect the drug supply on a due date, a reminder letter was posted on the fourth day and, if necessary, a health visitor visited the home a week later. In the intensive (I) policy, a health visitor visited the home on the 4th day and, if necessary, a week later and at 1 and at 2 months. The main analyses concern 150 patients (75 R, 75 I), of whom 16 R and 15 I patients had a positive culture. A total of 29 patients (11 R, 18 I) did not default at any time. For the remaining 64 R and 57 I patients, the mean numbers of defaults were 3.0 and 2.3, and the mean numbers of defaulter retrieval actions were 4.3 and 3.8, respectively. The home visit as the first action (I series) was successful in retrieving defaulters on 65% of 132 occasions, while the reminder letter (R series) was successful in 56% of 193 occasions (P = 0.1). Following the second action, which was a home visit in both the series, these proportions became 80% and 84%, respectively. in the I series, 22 third and 18 fourth actions were taken, but the patient was retrieved in only 4 and 0 instances respectively. The mean number of drug collections during the year was significantly higher in the I series (9.8) than in the R series (8.6). Finally, the proportions of patients who made 12 collections in a 15-month period, a satisfactory target under Indian Programme conditions, were 69% and 52%, respectively (P = 0.07).

Adolescent↗
PubMed1980

A study of the accuracy, and factors influencing accuracy, of home addresses of patients obtained by registry clerks and address cards in four large towns in South India.

In 4 large towns in South India with illiteracy levels of 26% to 40%, the efficiency of registry clerks in eliciting the home addresses of 1338 out-patients was assessed, by verifying receipt of a letter posted to the patients. The efficiency was found to be very poor, namely 66%. Moreover, the accuracy of address was substantially poorer for illiterate patients and for patients living for relatively short durations at their present address. Our innovation, the address card, on which the home address was recorded by a knowledgeable literate person of the patient's choice, was returned by 98% of the patients, and the addresses were found accurate in 84%; the findings were similar in the 4 towns and were unaffected by any patient characteristic. The substantially better results with the address card were found in both illiterate and literate patients. These findings establish the address card as a simple, inexpensive and efficient device for obtaining accurate addresses.

Adult↗
PubMed1980

Mathematical study of the contamination phenomenon in the culture of tubercle bacilli.

This paper demonstrates that when 'spot' specimens of sputum are cultured for tubercle bacilli on Löwenstein-Jensen medium, bacterial contamination occurs at random and follows a Poisson distribution. Over a period of 14 years, contamination rates with overnight 'collection' specimens (4.5 to 10.2%) were substantially higher than with spot specimens (1.3 to 4.0%), but the correlation between the two was very high (r = 0.98). In contrast to spot specimens, the incidence of contamination with collection specimens was significantly higher for females than for males, and significant variation was also found between patients of the same sex. In consequence, the Poisson distribution, which assumes a constant contamination rate for all patients, did not provide a satisfactory fit to the data on collection specimens. However, a negative binomial distribution, which incorporates individual variability in contamination rate, provided a good fit. The reasons for individual variability are discussed.

Bacteriological Techniques↗
PubMed1979

Efficiency of address cards, experienced health visitors and motivated registry clerks in obtaining the home address of urban patients in South India.

The address card, a card on which the patient's home address is asked to be recorded by the local postman, or by a knowledgeable and literate neighbour, relative or friend, was investigated for acceptability and efficiency in 4 tuberculosis out-patient clinics, in an urban community with substantial levels of illiteracy in Madras City. In the 4 clinics combined, 96% of the patients who reattended returned the completed card. Letters posted to the address on the cared were received by 85% of 419 patients, while 5% were returned by the post office as undelivered and a further 4% were, in all probability, not delivered; no information was available about the remaining 6%. A formal comparison in 392 of the above patients demonstrated the address card method to be significantly more efficient than interrogation by experienced health visitors. A retrospective comparison suggested that the efficiency of experienced health visitors was slightly better than that of highly motivated registry clerks, the proportions of letters received being 72% and 65% respectively.

Community Health Nursing↗
PubMed1979

An investigation of the accuracy of the home address given by patients in an urban community in South India.

Studies were undertaken in three tuberculosis clinics in Madras, a large Indian city with a good civic organization, to assess the accuracy of address recorded routinely by registry clerks at the patient's first clinic attendance. The accuracy was poor, with 20% to 30% of the letters posted not reaching the patients. It was appreciably improved, by 10% to 20%, by supplementing the clerk's efforts with questioning by a motivated, experienced health visitor. An address card, a card on which the patient's address was recorded by the local postman or a literate neighbour, relative or friend, was returned by 90% to 94% of the patients, and the accuracy of addresses was found to be at least as good as that obtained with the health visitor. Even when all three sources of information were considered, the patient's home could not be traced in 3% of cases and was found with difficulty in 4%.

Community Health Nursing↗
PubMed1978

Comparison of various measures of sensitivity of M. tuberculosis to ethambutol.

A sensitivity test for ethambutol was standardised, and performed on cultures isolated from patients before and after the start of chemotherapy with ethambutol and isoniazid. A discrimination type of approach was employed and three criteria of resistance were evolved: (a) growth of 20 colonies or more on ethambutol 4 microgram/ml, using a standard inoculum; (b) a proportion of 25% or more on ethambutol 1.4 microgram/ml; (c) a proportion of 5% or more on ethambutol 2 microgram/ml. The MIC definition appears to be the best in view of its simplicity and insensitivity of the classification (as sensitive or resistant) to variations in inoculum size.

Drug Resistance, Microbial↗
PubMed1976

Retreatment of drug-sensitive relapses of pulmonary tuberculosis following chemotherapy with standard drugs.

Forty-four tuberculous patients who relapsed with strains sensitive to the initial drugs they had received, namely streptomycin and isoniazid, were retreated with the same drugs for a year. One died of tuberculosis, and two had treatment changed for unfavourable response. All the other 41 showed a bacteriological response, and all but one were culture-negative at 1 year or when last assessed.

Aminosalicylic Acid↗
PubMed1976

Studies of immediate adverse reactions to different doses of a slow-release preparation of isoniazid.

'Double-blind' studies were carried out to assess the incidence of immediate adverse reactions to different doses of a slow-release preparation of isoniazid (matrix isoniazid). Individual doses of 30 mg/kg matrix isoniazid were well-tolerated but higher doses resulted in giddiness, the incidence being dose-related. The giddiness was characterized by a late onset and was usually present even at 24 hours. A few patients complained of gastro-intestinal symptoms. It is concluded that matrix isoniazid can be given to Madras patients in doses of 30-40 mg/kg without risk of an undue incidence of immediate adverse reactions.

Adult↗
PubMed1976

Study of adverse reactions to a once-weekly regimen of streptomycin plus a slow-release preparation of isoniazid in high dosage for six months.

A once-weekly regimen of streptomycin (1 g) plus a slow-release preparation of isoniazid (matrix isoniazid) in high dosage, namely 50 mg/kg body-weight for rapid inactivators of isoniazid and 35 mg/kg for slow inactivators, was prescribed for 6 months to 64 tuberculous patients (27 rapid, 37 slow). The regimen was tolerated by most the of the patients. However, 4 rapid and 3 slow inactivators had a modification of the regimen, mainly for giddiness. There were no cases of peripheral neuropathy. No adverse effects on haemopoiesis or hepatic or renal functions were observed in any of the patients. It is concluded that it is feasible to administer matrix isoniazid in dosages considerably higher than ordinary isoniazid, in once-weekly chemotherapy.

Adolescent↗