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Biomedical subjects

N Subramanian

Publications and source records attributed to N Subramanian.

102 records · Page 6Linked to original sources
PubMedDate not supplied

Low serum cortisol in term newborns with refractory hypotension.

OBJECTIVES: The aim of this study is to measure baseline serum cortisol levels and clinical response to glucocorticoid therapy in a group of term infants with refractory hypotension. STUDY DESIGN: Seven term newborns with refractory hypotension were included. Serum cortisol levels were drawn before initiation of glucocorticoid therapy and measured by either fluorescence polarization immunoassay or radioimmunoassay. Baseline blood pressures, heart rate, and inotropes doses were recorded at baseline, then 4, 8, 12, 24, 48, 72, and 96 hours after glucocorticoid therapy. Urine output and volume expanders the infants received were recorded 24 hours before and after glucocorticoid therapy. Dexamethasone was used at a starting dose of 0.2 mg/kg per day divided every 12 hours. The statistical analysis was done using analysis of variance with repeated measures and paired t-test. RESULTS: Serum cortisol levels of the infants ranged from 2.0 to 15.4 micrograms/dl. After initiation of glucocorticoid therapy, there was significant improvement of blood pressure. Vasopressors were rapidly weaned and discontinued within 72 hours. In three of seven infants, no volume expanders were required after initiation of steroids, and none needed volume expanders after 2 days. Urine output increased significantly within 24 hours. All infants survived. CONCLUSIONS: Glucocorticoids improved pressure and stabilized clinical conditions of a group of term newborns with refractory hypotension. Serum cortisol levels of these infants were relatively low. We speculate that a subset of critically ill term infants has relative adrenal insufficiency and glucocorticoid therapy may be essential.

Blood Pressure↗
PubMedDate not supplied

Preparation, characterization and in vivo studies of proliposomes containing Cyclosporine A.

The present study was undertaken to prepare proliposomes of Cyclosporine A (CsA) to increase its oral bioavailability. The proliposomes were prepared by spraying a solution of CsA, egg lecithin and cremophor EL in methanol-chloroform mixture onto directly compressible lactose (carrier) in a rotary evaporator. A dry free flowing powder of proliposomes was obtained. The dry proliposomal powder was characterized for surface morphology by scanning electron microscopy (SEM). Then the proliposomes were hydrated with distilled water to produce liposomes, which were characterized for particle size distribution, % drug entrapment, and morphological characteristics by transmission electron microscopy (TEM). The liposomes exhibited good entrapment of about 99%. The entrapment of CsA in liposomes was found to be dependent mainly on the drug:lipid ratio. Bioavailability studies were carried out for three different formulations of CsA i.e., free drug suspension; proliposomes derived liposomes and marketed formulation (Pannimun Bioral, Microemulsion) on male SD rats. The results of bioavailability studies indicated that the difference in the mean drug concentration of the free drug and the liposomes was found to be statistically significant (p < 0.05, p value is 0.032). The absorption constant for liposomal product was much greater (10.26 h(-1)) than for free drug solution (1.2 h(-1)) or the marketed sample of microemulsion (2.51 h(-1)) and the volume of distribution was found to be less for liposomes (7629.88 ml/kg) than that of the free drug solution (10971.92 ml/kg) and marketed microemulsion (9012.07 ml/kg). The results of these studies have shown that a stable proliposomal formulation of CsA for oral administration can be prepared which can be easily hydrated into liposomes from which CsA can exert its clinical effects with a better oral bioavailability.

Animals↗
PubMedDate not supplied

Phenobarbital does not prevent total parenteral nutrition-associated cholestasis in noninfected neonates.

Cholestasis associated with total parenteral nutrition (TPN) is a serious complication of this therapy for which there is no known treatment other than beginning enteral feeds. Phenobarbital is commonly used in other cholestatic disease states, but its benefit in this syndrome has not been demonstrated. We conducted a retrospective review of phenobarbital use in neonates receiving concurrent TPN. Thirty-one noninfected neonates were studied. They were without evidence of intrinsic liver disease at the institution of exclusive TPN therapy. For the purposes of this study, TPN-associated cholestasis was defined as a serum bilirubin in excess of 3 mg/dl at postnatal age of 3 weeks or more. Fourteen of the study infants received phenobarbital therapy for neurologic indications. Sixty percent of the phenobarbital-treated infants developed TPN-associated cholestasis, as compared to 33% of the untreated patients. Phenobarbital therapy was not effective in preventing TPN-associated cholestasis.

Cholestasis↗
PubMedDate not supplied

An epidemiologic study of osteogenic sarcoma in Malaysia. Incidence in urban as compared with rural environments and in each of three separate racial groups, 1969-1972.

To explore the possibility that environmental and/or genetic factors may yield clues to the etiology of osteogenic sarcoma, an epidemiologic retrospective study of all cases of osteogenic sarcoma in a country with clear geographic and racial variables (Malaysia) was conducted covering a 4-year period. Sixty-eight cases were identified (+85% of the predicted total). The incidence (cases per 100,000 population per year) was 0.11 in Malay, 0.23 in the Chinese, and 0.23 in the Indian. The urban versus rural incidence in the Malay was 0.22 versus 0.09, and in the Chinese 0.31 versus 0.18. The Indian population was too small when dividied into urban and rural segments to be significant.

Adolescent↗
PubMedDate not supplied

Reaction time in clinical diabetes mellitus.

Visual and auditory reaction times were studied in patients suffering from diabetes mellitus and age matched normal control subjects. Auditory reaction times were shorter than visual reaction times in control subjects as well as diabetic patients. In diabetic patients, there was significant prolongation of visual as well as auditory reaction times. Further studies of reaction times for various modalities may provide a better insight into the neurological disturbances in diabetes mellitus.

Adult↗
PubMedDate not supplied

Effect of cigarette smoking on leucocytes in South Indians.

A study was done on 200 male hospital employees of similar socio-economic status in the age group of 25-45 years. The smokers had a significantly higher total leucocyte count and there was a significant positive correlation (r = 0.388) between the quantity of cigarettes smoked and leucocyte count. Besides this a significant lymphocytosis and neutropenia was also observed. It is suggested that total leucocyte count may be taken as an index for the degree of smoking.

Adult↗
PubMedDate not supplied

Strategies in the design of peptidoleukotriene antagonists.

The research of the last two decades in the field of SRS-A and peptidoleukotriene (pLT) antagonists has provided information for the design of potent pLT antagonists, which share some or all of the following structural elements: (1) a lipophilic anchor, which fits into the lipophilic pocket of the LTD4 receptor; (2) a central lipophilic unit mimicking the tetraene system of LTD4; (3) one or two acidic groups, as mimics of the cysteinyl-glycine unit and/or the carboxylic group in the eicosanoid backbone of LTD4; (4) spacers connecting these elements. Potent pLT antagonists lacking a second polar binding group compensate by stronger interaction in other regions of the receptor. Identification of pLT antagonists is based on lead optimisation, preparation of pLT analogs and on the knowledge of the pLT receptor.

Animals↗