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Biomedical subjects

R Biswas

Publications and source records attributed to R Biswas.

At least 109 records · Page 6Linked to original sources
PubMed1980

Relationship between mitochondrial ATPase and membrane lipids from developing human placenta.

Mitochondrial lipids and ATPase activity have been studied in developing human placenta. The enzyme activity in the placenta increases steadily with gestational age until the 18th to 21st week, and decreases in the second half of pregnancy. Both Mg2+ and Ca2+ ions have been found to activate the enzyme system. The solubilization of membrane lipids by deoxycholate inhibits the enzyme activity. Total lipid and total phospholipid contents of the mitochondrial membranes also increase during the early development of the placenta with peaks in the 14th to 17th week, after which the levels decrease. However, the percentage composition of individual phospholipids remains almost the same throughout pregnancy. The profile of the ATPase activity exhibits a correlation with that of membrane lipids in human placenta during intrauterine development of the tissue.

Adenosine Triphosphatases↗
PubMed1980

Long-term contraception with Depo-Provera: a clinical evaluation.

Depo-Provera has been used as a long-acting injectable contraceptive. The results of the study carried out for more than 2 years indicate that the depot formulation of medroxyprogesterone acetate (DMPA, Depo-Provera) at a dose of 150 mg at 90-day intervals appears to be acceptable to some women of this part of India, though many of them experience menstrual problems. However, irregular and/or excessive menstrual bleeding diminishes with long-term use of the contraceptive and a high percentage of users become amenorrheic. No major adverse reactions were observed and the minor side effects are comparable to those reported for the oral contraceptives. There was a tendency for weight-gain by the patients and the endometrium became atrophic or "resting" with the prolongation of the therapy.

Adolescent↗
PubMed1979

Evidence for the occurrence of an ecto-(adenosine triphosphatase) in rat epididymal spermatozoa.

Intact spermatozoa from rat cauda epididymis possess a Mg2+-dependent ATPase activity that hydrolyses externally added [gamma-32P]ATP. The ATPase reaction was linear with time for approx. 6 min and there was no detectable uptake of ATP by these cells. The ATPase activity of the whole spermatozoa was not due to leakage of the intracellular enzymic activity, contamination of the broken cells or any possible cell damage during incubation and isolation of spermatozoa. The activity of the enzyme was strongly inhibited (approx. 85%) by p-chloromercuribenzenesulphonic acid (50 microM) or the diazonium salt of sulphanilic acid (50 microM), which are believed not to enter the cells, whereas ouabain (0.5 mM), NaF (10 mM), NaN3 (2.5 mM) and oligomycin (5 microM) had no appreciable effect on the activity of the spermatozoal APTase. There was little loss of ATPase activity from the cells when washed with 0.5 mM-EDTA and an iso-osmotic or hyperosmotic medium. These data are consistent with the view that the observed ATPase activity is located on the external surface of spermatozoa. The sperm ecto-ATPase activity is resistant to the action of proteinases (50 micrograms/ml), namely trypsin, chymotrypsin and Pronase. Studies with various unlabelled phosphate esters indicate that the sperm ecto-ATPase is not a non-specific phosphatase and it has high degree of substrate specificity for ATP.

4-Chloromercuribenzenesulfonate↗
PubMed1978

[Asymptomatic chronic-persisting hepatitis B in a young child as source of infection of hepatitis B within a family (author's transl)].

Five members of an eight-member family fell ill with an acute icteric hepatitis B of the same subtype within eleven months. In all probability the source of the infection was a just over one-year-old fostered child with asymptomatic chronic persisting hepatitis B and signs of massive viraemia (usually high HBs antigen concentration, high virus-specific DNA-polymerase activity and positive HBe antigen test). No relation could be demonstrated between HLA constellation and illness in the family members. Since no specific treatment is available, the only possible prophylactic measure is to isolate the child in the present environment, to avoid further cases of the disease.

Acute Disease↗
PubMed1977

Simultaneous presence of HBsAg and anti-HBs in the serum of different subtypes (serological and immunofluorescent studies).

Serological and immunofluorescent studies were performed in 3 patients with the simultaneous presence of HBsAg and anti-HBs in the serum. Our investigations revealed the following results: HBsAg and anti-HBs in the serum were of different subtypes. HBsAg in the serum and in the liver had the same subtype. HBsAg in the liver did not react with the circulating anti-HBs in the patient's own serum. HBsAg-anti-HBs immune complexes could not be detected in the serum or in the liver tissue. These phenomena can most readily be explained by at least 2 contacts with hepatitis-B-viruses of different subtypes, one leading to immune tolerance and the other to an immune response. In a follow-up study there was no evidence for a short-term change in HBsAg subtype. Unexplained remains the cause why one contact with HBV did lead to immune tolerance and a second to an immune response.

Adult↗
PubMed1975

Effect of ovariectomy and replacement therapy on the tissue lipid pattern in rats.

Ovariectomy increases the percentage of total lipids in liver, kidney and uterus of intact cyclic rats. Estrogen and progesterone, when administered individually to ovariectomized rats, caused a decrease in the total lipid content of all tissues. Th effect of progesterone in estrogen-primed rats is not significant. Triglyceride and cholesterol content increases after ovariectomy; treatment with estrogen in ovariectomized rats led to a decrease in the concentration of these lipids. Progesterone has no significant effect on these lipids but showed an antagonistic action when given in estrogen-primed ovariectomized rats. The proportions of ethanolamine, choline and inositol phospholipids decreased after spaying and increased when estrogen was given to spayed rats. Progesterone alone had effect only on the uterus whereas progesterone administered to estrogen-primed rats showed an antagonistic effect in all tissues.

Animals↗
PubMedDate not supplied

42,000-molecular weight EGF receptor has protein kinase activity.

The epidermal growth factor (EGF) receptor and other growth factor receptors have been shown to possess tyrosine-specific protein kinase activity. Before the demonstration of kinase activity in growth factor receptors, tyrosine kinases of molecular weight (MW) 60,000 (60K) were found to be encoded by the src oncogene and other oncogenes related to src. Our earlier work on intracellular processing of the EGF receptor, a 170,000-MW polypeptide, provided evidence for proteolytic separation of well defined structural domains, and suggested to us the possibility of separating functional domains by limited proteolysis. The isolation of such kinase domains should facilitate comparison of the receptor/kinase with other well characterized kinases including those of oncogene origin. We report here the identification of a catalytically functional 42K kinase derived proteolytically from the isolated human EGF receptor. This fragment, comparable in size to pp60src, carries the kinase ATP-binding site, and functions catalytically even after detachment from the EGF-binding site and the major autophosphorylation region.

Adenosine Triphosphate↗
PubMedDate not supplied

Effect of continual light deprivation and alpha-2u-globulin replacement therapy on serum concentration of gonadotropins and testicular activity in rats.

Prolonged darkness caused a fall in testicular 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) activity and diminished spermatogenesis, serum levels of gonadotropins, testosterone and alpha 2u-globulin. Administration of alpha 2u-globulin at a dose of 1.5 mg rat-1 per day for 7 days after 68 days of light deprivation, reversed the 17 beta-HSD activity and serum levels of gonadotropins, testosterone and alpha 2u-globulin, while spermatogenesis was restored to normal. The animals kept in prolonged darkness for 68 days and then received saline (7 days in light-dark cycle, 14 L: 10 D), showed no significant changes of testicular activity, serum levels of gonadotropins, testosterone and alpha 2u-globulin, when compared with dark-exposed animals (68 days) receiving rabbit serum (7 days in light-dark cycle, 14 L: 10 D). These results suggest that alpha 2u-globulin plays an important role in testicular function in dark-exposed rats by inducing gonadotropins and testosterone secretion.

Alpha-Globulins↗
PubMedDate not supplied

Risk factors of acute respiratory infections in underfives of urban slum community.

To ascertain the risk factors of Acute Respiratory Infections (ARI) in children, a prospective study was conducted for a period of one year among 112 underfives in urban slum community of Calcutta. Incidence of ARI was found significantly higher in undernourished children of poor socio-economic class. Parental smoking habit and solid fuel use for cooking were recognised as important risk factors of ARI.

Acute Disease↗
PubMedDate not supplied

A community based study on health impact of flood in a vulnerable district of West Bengal.

In order to ascertain the disaster vulnerability and health risks of flood in Hooghly district of West Bengal, this community based study was conducted through record analysis, interview of concerned authorities and household survey of morbidities before and after flood. Two blocks, with most of its population, were found to be the worst affected among all the disaster vulnerable blocks of the district. Incidence of diarrhoea, other enteric diseases and respiratory infections were significantly higher (P < 0.05) among the population in flood affected blocks, compared to the unaffected. The attack rate of diarrhoea in the flood affected population had increased significantly following flood (P < 0.05).

Diarrhea↗
PubMedDate not supplied

Nutritional status of pavement dweller children of Calcutta City.

Pavement dwelling is likely to aggravate malnutrition among its residents due to extreme poverty, lack of dwelling and access to food and their exposure to polluted environment. Paucity of information about nutritional status of street children compared to that among urban slum dwellers, squatters or rural/tribal population is quite evident. The present study revealed the magnitude of Protein Energy Malnutrition (PEM) and few associated factors among a sample of 435 underfives belonging to pavement dweller families and selected randomly from clusters of such families, from each of the five geographical sectors of Calcutta city. Overall prevalence of PEM was found almost similar (about 70%) to that among other 'urban poor' children viz. slum dwellers etc., but about 16% of them were found severely undernourished (Grade III & V of IAP classification of PEM). About 35% and 70% of street dweller children had wasting and stunting respectively. Severe PEM (Grade III & IV) was more prevalent among 12-23 months old, girl child, those belonged to illiterate parents and housewife mothers rather than wage earners. It also did increase with increase of birth rate of decrease of birth interval.

Child, Preschool↗