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Biomedical subjects

M Viswanathan

Publications and source records attributed to M Viswanathan.

214 records · Page 12Linked to original sources
PubMedDate not supplied

Anthropometric studies in diabetes in the Tropics.

Anthropometric studies were carried out in three groups of diabetics seen in southern India, namely fibrocalculous pancreatic diabetes (FCPD) (n = 49) (a subtype of malnutrition related diabetes), insulin dependent diabetes mellitus (IDDM) (n = 55) and non-insulin dependent diabetes mellitus (NIDDM) (n = 104). Both FCPD and IDDM had significantly lower body mass index, skinfold thickness (triceps, biceps, subscapular and suprailiac), mid-arm circumference and fat mass compared to controls and NIDDM patients, (p less than 0.001 for all parameters). FCPD and IDDM males did not show any significant differences in any of the anthropometric parameters studied. Among the females, FCPD had lower triceps skinfold measurements (p = 0.007) and mid-arm circumferences (p less than 0.05) compared to IDDM patients. Patients with NIDDM did not show any significant difference compared to the control group. This study shows that both FCPD and IDDM patients have lower body mass and fat mass compared to NIDDM patients and control subjects.

Adipose Tissue↗
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Expression of angiotensin II AT2 receptors in the rat skin during experimental wound healing.

We localized and characterized angiotensin II AT1 and AT2 receptors in the skin of 2-week-old rats during experimental wound healing. Both AT1 and AT2 were present in the skin. Three days after wounding, the expression of angiotensin II receptors was significantly enhanced in the dermis as well as in a localized band within the superficial dermis of the skin surrounding the wound. The major proportion of this increase was due to angiotensin II AT2 receptors. Our results suggest a physiological role for AT2 receptors in the process of tissue repair.

Animals↗
PubMedDate not supplied

Neuroendocrinology of pyridoxine deficiency.

Dihydroxyphenylalanine decarboxylase and 5-hydroxytryptophan decarboxylase respectively have high and low affinities for pyridoxal phosphate. In the pyridoxine-deficient animal, hypothalamic serotonin content is significantly reduced without any change in catecholamine levels. Hypothalamic neurotransmitters affect the hypothalamo-pituitary-end organ axes. Specifically, the decrease in hypothalamic serotonin in the pyridoxine-deficient rat results in tertiary hypothyroidism. In addition, pineal function is affected in deficient animals due to decreased synthesis of melatonin.

Animals↗
PubMedDate not supplied

Radiological appearance of pancreatic calculi in tropical versus alcoholic chronic pancreatitis.

Tropical and alcoholic forms of chronic pancreatitis differ in their clinical, aetiological and epidemiological features. We compared the radiological appearances of pancreatic calculi seen on plain roentgenogram of the abdomen of 89 patients with tropical calcific pancreatitis (TCP) and 32 patients with alcoholic calcific pancreatitis (ACP) seen in Madras, Southern India. While TCP was characterized by the frequent occurrence of large, discrete, dense calculi, patients with ACP had typically small, speckled calculi with irregular, hazy margins. The calculi in TCP resembled those described for hereditary pancreatitis. This is the first report comparing the radiological appearances of TCP and ACP patients seen at the same centre.

Adult↗
PubMedDate not supplied

Prospects of the clinical utilization of melatonin.

This review summarizes the present knowledge on melatonin in several areas on physiology and discusses various prospects of its clinical utilization. Ever increasing evidence indicates that melatonin has an immuno-hematopoietic role. In animal studies, melatonin provided protection against gram-negative septic shock, prevented stress-induced immunodepression, and restored immune function after a hemorrhagic shock. In human studies, melatonin amplified the antitumoral activity of interleukin-2. Melatonin has been proven as a powerful cytostatic drug in vitro as well as in vivo. In the human clinical field, melatonin appears to be a promising agent either as a diagnostic or prognostic marker of neoplastic diseases or as a compound used either alone or in combination with the standard cancer treatment. Utilization of melatonin for treatment of rhythm disorders, such as those manifested in jet lag, shift work or blindness, is one of the oldest and the most successful clinical application of this chemical. Low doses of melatonin applied in controlled-release preparation were very effective in improving the sleep latency, increasing the sleep efficiency and rising sleep quality scores in elderly, melatonin-deficient insomniacs. In the cardiovascular system, melatonin seems to regulate the tone of cerebral arteries; melatonin receptors in vascular beds appear to participate in the regulation of body temperature. Heat loss may be the principal mechanism in the initiation of sleepiness caused by melatonin. The role of melatonin in the development of migraine headaches is at present uncertain but more research could result in new ways of treatment. Melatonin is the major messenger of light-dependent periodicity, implicated in the seasonal reproduction of animals and pubertal development in humans. Multiple receptor sites detected in brain and gonadal tissues of birds and mammals of both sexes indicate that melatonin exerts a direct effect on the vertebrate reproductive organs. In a clinical study, melatonin has been used successfully as an effective female contraceptive with little side effects. Melatonin is one of the most powerful scavengers of free radicals. Because it easily penetrates the blood-brain barrier, this antioxidant may, in the future, be used for the treatment of Alzheimer's and Parkinson's diseases, stroke, nitric oxide, neurotoxicity and hyperbaric oxygen exposure. In the digestive tract, melatonin reduced the incidence and severity of gastric ulcers and prevented severe symptoms of colitis, such as mucosal lesions and diarrhea.

Adjuvants, Immunologic↗
PubMedDate not supplied

Vascular melatonin receptors.

High-affinity melatonin receptors are expressed in the tail artery of the rat and arteries forming the circle of Willis of the rat and certain primates. The characteristics of the vascular melatonin receptors seem to be similar to the ones described in the central nervous system. The expression of vascular melatonin receptors in the rat is differentially regulated by factors such as strain and age, and in the female by reproductive hormones. Functional studies using the caudal artery of the rat suggest that melatonin regulates vascular tone. The highly restricted distribution of melatonin receptors in arteries involved in regulating blood flow to areas involved in heat dissipation suggests that vascular melatonin receptors may have a specific function in thermoregulatory homeostasis.

Animals↗
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C-Peptide responses to glucose load in maturity-onset diabetes of the young (MODY).

Pancreatic beta cell responses were measured in obese and nonobese maturity-onset diabetes of the young (MODY) patients by estimating serum immunoreactive insulin (IRI) and C-peptide (CP) during oral glucose tolerance testing (OGTT). The serum CP responses were generally low in MODY patients and more pronounced in obese patients. The IRI responses were heterogenous; some patients had normal and others low responses. It was observed that in several patients there was a relatively higher IRI concentration in comparison with the CP values, as indicated by low CP and normal IRI values. This is suggestive of altered metabolic fates of insulin and CP in the MODY patients.

Adult↗
PubMedDate not supplied

High prevalence of maturity-onset diabetes of the young (MODY) among Indians.

This article describes the high prevalence of maturity-onset diabetes in the young (MODY) in an Indian clinic population of diabetic patients. MODY appears to be more common among Indians than among Caucasians. Only 27% of MODY patients had definite autosomal-dominant inheritance. In 73% the mode of inheritance was not definite. Microvascular complications were common and macrovascular complications rare. The high prevalence of MODY in this diabetes clinic might suggest an ethnic variation in diabetes.

Adult↗
PubMedDate not supplied

Abnormalities in insulin secretion in healthy offspring of Indian patients with maturity-onset diabetes of the young.

Serum C-peptide (CP) and immunoreactive insulin (IRI) responses were studied in 47 euglycemic offspring of patients with maturity-onset diabetes of the young (MODY). Mean IRI responses were not significantly different in nonobese offspring of MODY patients (O-MODY) but they were lower in obese O-MODY than in respective controls. Mean CP responses were low in both groups, the change being more pronounced in obese O-MODY. These findings indicate that alterations of secretion and metabolism of insulin can be detected even before glucose intolerance is seen in O-MODY.

C-Peptide↗
PubMedDate not supplied

Faecal chymotrypsin assay in tropical and alcoholic chronic pancreatitis.

Faecal chymotrypsin (FCT) levels were estimated in a group of patients with tropical chronic pancreatitis (TCP) and compared with patients with alcoholic chronic pancreatitis (ACP), 'gastrointestinal' controls and 'healthy' subjects. Exocrine pancreatic insufficiency as assessed by low faecal chymotrypsin levels (less than 5.8 mu/g) were present in 85.7 per cent of TPC and 84.6 per cent of ACP patients. Mean FCT levels as well as the distribution of FCT values were similar in TCP and ACP patients and significantly lower than the two control groups (P less than 0.001). There was also no difference with respect to mean FCT levels between subgroups of TCP patients with and without diabetes and those with and without calcification. Faecal chymotrypsin assay is a simple test for diagnosis of chronic pancreatitis in gastroenterological centres in tropical countries.

Alcoholism↗
PubMedDate not supplied

Insulin-specific IgE in serum of 67 diabetic patients against human insulin (Novo), porcine insulin, and bovine insulin. Four case reports.

We have investigated the binding of insulin-specific IgE (IgE1) to porcine, bovine, and human insulin (Novo), pancreatic polypeptide, and a-component in serum samples from type I diabetic patients treated with insulin preparations of different purity. Patients treated with porcine or mixed-species purified insulin (monocomponent) did not differ significantly from a nondiabetic control group. Hence, in these groups no IgE1 could be detected against any of the components investigated. Serum samples from patients treated with five-times recrystallized insulin preparations and patients with insulin allergy showed a significantly greater binding of IgE1 to the three species of insulin; IgE1 binding was greatest to bovine insulin and least to human insulin. The difference in binding was most significant in the allergic patients (P less than 0.001), probably due to differences in the affinity. It is concluded that conventional (recrystallized) insulin induces more IgE1 than monocomponent insulin. Data are presented on confirmed allergy in four diabetic patients whose allergy disappeared upon transfer to human insulin.

Aged↗
PubMedDate not supplied

Increased LDL cholesterol in non-insulin-dependent diabetics with maculopathy.

Serum cholesterol and its various lipoprotein fractions and triglycerides were measured in 50 non-insulin-dependent diabetic patients, 25 without retinopathy (group A) and 25 with diabetic maculopathy (group B) initially before control of diabetes, and again, after achieving good metabolic control. The lipid parameters were also estimated in 25 healthy non-diabetic subjects. The groups were well matched for sex, age, duration of diabetes and body weight. Mean serum total cholesterol and LDL cholesterol levels were significantly higher in group B when compared to group A, before and after achieving good metabolic control of diabetes (p less than 0.001). Mean total/HDL cholesterol and mean LDL/HDL cholesterol ratios were also significantly increased in group B as compared to group A (p less than 0.01) both before and after good diabetic control in these patients. Mean serum HDL and VLDL cholesterol and triglyceride concentrations were similar in groups A and B. The mean serum lipid concentrations in the diabetic patients without retinopathy (group A) were comparable to those of non-diabetic subjects.

Adult↗