Serum insulin levels in non-obese, non-diabetic Asian Indians with acute coronary and non-coronary events.

Significant insulin resistance and hyperinsulinemia has been observed to be associated with coronary heart disease in epidemiological studies, particularly so in Asian Indians. This study attempted to investigate if hyperinsulinemia accompanies acute cardiovascular events in Asian Indians, and that it is not a metabolic response to acute stress alone. To test this hypothesis, a case-control study was carried out in a tertiary referral hospital in northern India. Group I (n = 19), consisting of non-diabetic, non-hypertensive, non-obese patients presenting with first episode of acute coronary event (first episode of angina or myocardial infarction) were compared with non-diabetic, non-hypertensive, non-obese patients of group II (n = 21) presenting with non-cardiovascular emergencies (severe abdominal pain e.g. uncomplicated ureteric colic or non-specific intestinal colic. Blood was analysed for glycosylated haemoglobin, fructosamine and insulin levels within 24 hours of the acute event. Elevated serum fructosamine was observed in 11 (57.8%) subjects in group I and 9 (42.9%) in group II (p = NS). Glycosylated haemoglobin was 6.8 +/- 0.1 percent in group I versus 5.9 +/- 0.04 percent in group II (p < 0.01). Three out of 11 subjects in group I and 1/9 subjects in group II having elevated serum fructosamine level also had increased glycosylated haemoglobin level. Five (26.3%) subjects in group I and 2 (9.5%) in group II with elevated glycosylated haemoglobin level were excluded from the analysis as these patients might have been diabetic. Mean serum insulin values were significantly higher in group I (161.3 +/- 8.15 micro IU/mL and 17.5 +/- 1.9 micro IU/mL in groups I and II, respectively; p < 0.001). Eleven (57.8%) subjects in group I had insulin values above 100 uIU/ml. The present study indicates that significant hyperinsulinemia accompanies acute cardiovascular events and it is not an acute response to pain or stress hyperglycemia. Markedly high insulin levels observed in these patients may have a potential role in the pathophysiology of acute coronary event, and may be further studied as a possible prognostic marker.

Methemoglobinemia in aluminium phosphide poisoning in rats.

Aluminium phosphide (AlP) a grain fumigant is the leading cause of intentional poisoning in North India. The mechanisms involved in toxicity are not known and there is no antidote till date. The present study was carried out to investigate the oxygen free radical generation, methemoglobinemia and effect of methylene blue treatment on survival time in rat model of AlP poisoning. AlP (50 mg/kg, intragastric) was administered in one group and the other group received AlP + Methylene Blue (MB) (0.1%, 1 mg/kg/5 min, i.v.). Malonyldialdehyde (MDA) and methemoglobin (MeHb) levels were measured at 10 and 30 min intervals. Blood MDA levels increased at 10 and 30 min after AlP exposure with simultaneous rise in MeHb levels suggesting methemoglobinemia could be due to increased oxygen free radical generation. Methylene blue caused a significant fall in both the parameters with prolongation of survival time. It is concluded that AlP causes methemoglobinemia responding to methylene blue treatment.

Hyperinsulinemia in non-obese, non-diabetic subjects with isolated systolic hypertension.

To investigate the inter-relationship of hyperinsulinemia and isolated systolic hypertension, 15 patients with isolated systolic hypertension (Group I) were compared to those having systolic and diastolic hypertension (Group II), and 14 age- and sex-matched controls (Group III). Significantly high triglycerides and total cholesterol were observed in Groups I and II (p < 0.001) and low high-density lipoprotein cholesterol in Group II (p < 0.001), when compared to controls. Significantly high number of patients had impaired glucose tolerance (80%; p = 0.0002 and 60%; p = 0.05) on oral glucose tolerance test in Groups I and II, respectively. Higher blood glucose values were observed in Group I as compared to Group III, at 0, 30, 60 (p < 0.05) and 120 minutes (p < 0.001). Subjects in all the three groups showed fasting normo-insulinemia. At 60 minutes during oral glucose tolerance test, higher insulin levels were seen in Groups I and II as compared to controls (p = NS). Peak insulin levels and area under curve for insulin were higher in Groups I and II as compared to controls (p = NS). The observations of the present study indicate that, similar to systolic and diastolic hypertension, several features of insulin resistance syndrome such as hyperinsulinemia, dyslipidemia and glucose intolerance accompany isolated systolic hypertension.

Role and functions of Poisons Information Centre.

The Poisons Information Centre (PIC) is a specialized unit providing information on prevention, early diagnosis and treatment of poisoning and hazard management. Most of the developed and many developing countries have well established poison control centres with poisons information service, patient management facility and analytical laboratory. In India, the National Poisons Information Centre (NPIC) was established in February, 1995 in the Department of Pharmacology at the All India Institute of Medical Sciences, New Delhi. The centre provides toxicological information and advice on the management of poisoned patients adopted to the level of the enquirer. The basis of this service are the databases on poisoning, drug reactions and also the continuous and systematic collection of data from the library. This information service is available round the clock. The PIC has the training responsibility extending to medical and other health professionals and community. The NPIC organized two successive training courses for medical professionals and para professionals at all health levels. Further, NPIC is a participant of INTOX project of IPCS/WHO, receiving regular yearly training on the use of INTOX database. Laboratory service is an essential component of a poisons control programme, providing analytical services on emergency basis to help in diagnosis and management. The NPIC is developing facilities for quick diagnosis of poisoning cases. Toxicovigilance and prevention of poisoning is another major function of PIC. The Centre has prepared manuals and leaflets on prevention and management cards on treatment of various poisonings. Thus the Centre provides a service with considerable health benefits, reducing morbidity and mortality from poisoning and gives significant financial savings to the community.

Involvement of renin-angiotensin system in hypertensive effect of cadmium in rats.

Role of renin-angiotensin system in hypertension induced by cadmium chloride (CdCl2) in rats has been investigated. Intravenous administration of CdCl (1 mg/kg) produced a biphasic response i.e. a transient fall followed by a marked and consistent rise in blood pressure. The peak hypertensive effect was accompanied by raised PRA levels. Pretreatment with captopril (1 mg/kg, i.v.) losartan (1 mg/kg, i.v.) or captopril + losartan attenuated the pressor response to Cd by 62%, 42% and 100% respectively in separate groups. Central administration of Cd (10 micrograms/rat, i.c.v.) showed a biphasic response similar to that observed after i.v. route. However, it was not accompanied by raised PRA levels. Prior treatment with losartan (10 micrograms/rat, i.c.v.) completely abolished the pressor response to Cd (i.c.v.) whereas it was not affected significantly by captopril (10 micrograms/rat, i.c.v.). On the other hand, centrally administered losartan only partially reduced the pressor response to i.v. Cd. The results are discussed in light of a differential involvement of central vs peripheral renin-angiotensin system in the hypertensive effect of Cd.

Cadmium induced nephrotoxicity in rats.

Onset of hypertension and nephropathy after 1,2, and 4 weeks of exposure to cadmium chloride (1 mg/kg, ip) was studied in rats by measuring changes in blood pressure and renal function (urinary output, electrolytes, serum creatinine, inulin clearance and Na+K+ ATPase). Significant decrease in body weight and rise in blood pressure were observed as early as one week of exposure while microalbuminuria was detected in 50% of the animals after 2 weeks. Na+K+ ATPase, a renal tubular enzyme, was depressed after 1 week with maximum lowering occurring after 4 weeks. There were no detectable changes in fluid intake, urine output, electrolytes, inulin clearance and serum creatinine even after 4 weeks. It is concluded that hypertension and tubular lesion set in earlier than glomerulopathy as indicated by microalbuminuria and the latter could be the consequence of rise in blood pressure.

Radioimmunoassay of angiotensin-II: methodology and standardization.

The study was planned to set up and standardize the radioimmunoassay of Ang-II and to validate the procedure in terms of precision, sensitivity, specificity and recovery. The application of the developed assay was studied in normal healthy volunteers and in patients of renovascular hypertension (RVHT) and renal hypertension (RH). Synthetic human Ang-II was coupled to BSA by carbodimide condensation to get the hapten carrier conjugate which was injected in rabbits to raise the antibodies. The titre of 1:250 showed significant binding (56.79%) and was used for the assay. The sensitivity of the assay was 2 pg/ml and cross-reactivity with analogues of Ang-II was minimum. Mean Ang-II levels in normal subjects was 16 +/- 3.6 pg/ml. In patients of RVHT and RH, the peripheral blood Ang-II levels were found to be 876 +/- 8.6 and 108 +/- 2.3 pg/ml respectively. In patients of unilateral RVHT, renal vein Ang-II levels of the affected side were significantly higher than the unaffected side (P < 0.001). The results indicate that unextracted samples can be successfully utilized to estimate Ang-II levels.

Clinical profile of cholera in young children--a hospital based report.

Clinical profile of cholera was studied in children attending Diarrhea Training and Treatment Unit from January-December 1993. Out of a total 8714 cases of acute watery diarrhea, 64 children (0.7%) were suspected to have cholera on the basis of acute onset loose water/rice watery stools, high purge rate with or without excessive vomiting and/or severe dehydration. Stool culture was positive for cholera in 33 cases (51.6%). All the isolates were V. cholerae 01 biotype El Tor serotype Ogawa. Sixty four per cent of stool culture positive cases were below 5 years of age. The results assume importance because out of 28 children < 2 years with clinical suspicion of cholera, 11 cases (39.3%) were culture positive for V. cholerae, youngest child being 3 months old. Comparison of various parameters revealed that presence of vomiting > 4 episodes/ day (p < 0.005), frequency of stools >12/24 hours (p <0.002), rice watery stools (p < 0.01) and presence of severe dehydration (p < 0.01) were significant parameters associated with positive stool culture. Beside examination of stool sample by hanging drop method was an excellent diagnostic tool (p < 0.001) with a sensitivity of 51.5%, specificity 100% and positive predictive value of 100%. The isolates of V. cholerae were susceptible to furazolidone, cephelexin, nalidixic acid, norfloxacin and gentamicin. Our observations indicate that cholera is not uncommon in infants and young children. Like children in the older age group, acute onset diarrhea with watery/rice watery stools and high purge rate with or without excessive vomiting and/or rapid development of severe dehydration should arouse suspicion of cholera in younger children also. They should be investigated for cholera even in non-endemic areas and in the absence of cholera outbreaks.

Plasma renin activity in normal healthy volunteers: effect of physiological variables.

Plasma renin activity was determined in hundred normal subjects of either sex (M = 65, F = 35, age range 2-70 yr) using Angiotensin-I test kits. The effect of various physiological variables viz, age, sex, posture and salt intake was determined. The basal values for PRA ranged from 1.19 +/- 0.09 ng/ml/hr for males and 1.02 +/- 0.12 ng/ml/hr for females in erect posture. In contrast high basal supine PRA was noticed in subjects on low salt diet, which showed a significant increase in erect posture. A marked decrease in PRA with advancing age in both the sexes with significantly low values at higher age range was noticed. Captopril produced an insignificant effect on PRA and BP in salt replete supine state, whereas in salt deplete state there was a significant rise in both the parameters.