Biomedical subjects

S B Prasad

Publications and source records attributed to S B Prasad.

At least 19 recordsLinked to original sources

PubMed1998

Vitamin C mediated protection on cisplatin induced mutagenicity in mice.

In present studies the development of chromosomal aberrations, micronuclei in bone marrow cells and sperm head abnormalities were used as mutagenic bioassay in Swiss albino mice treated with cisplatin alone or ascorbic plus cisplatin. It was noted that in the combined treated hosts the frequency of all the mutagenic parameters were always significantly less than that treated with cisplatin alone. These findings suggest a protective role of ascorbic acid against cisplatin induced mutagenic potentials. Interestingly, in combined treated hosts glutathione (GSH) level in bone marrow cells increased significantly which may suggest a possible mechanism of ascorbic acid mediated protection against cisplatin induced mutagenic potentials in the hosts.

Animals↗

PubMed1998

Cardiovascular effects of ozone exposure in human volunteers.

We hypothesized that ozone (O3) exposure acutely affects cardiovascular hemodynamics in humans and, in particular, in subjects with essential hypertension. We studied 10 nonmedicated hypertensive and six healthy male adults. Each subject, after catheterization of the right heart and a radial artery, was exposed in an environmentally controlled chamber to filtered air (FA) on one day and to 0.3 ppm O3 on the following day for 3 h with intermittent exercise. Relative to FA exposure, O3 exposure induced no statistically significant changes in cardiac index, ventricular performance, pulmonary artery pressure, pulmonary and systemic vascular resistances, ECG, serum cardiac enzymes, plasma catecholamines and atrial natriuretic factor, and SaO2. The overall results did not indicate major acute cardiovascular effects of O3 in either the hypertensive or the control subjects. However, mean preexposure to postexposure changes were significantly (p < 0.02) larger with O3 than with FA for rate-pressure product (1,353 beats/min/mm Hg) and for heart rate (8 beats/min); these responses were not significantly different between the hypertensive and the control subjects. Significant O3 effects were also observed for mean FEV1 (-6%), and AaPO2 (> 10 mm Hg increase), which were not significantly different between the two groups. These results suggest that O3 exposure can increase myocardial work and impair pulmonary gas exchange to a degree that might be clinically important in persons with significant preexisting cardiovascular impairment, with or without concomitant lung disease.

Adult↗

PubMed1994

Antitumor effect of cisplatin against murine ascites Dalton's lymphoma.

Cisplatin treatment brings about complete regression of ascites Dalton's lymphoma in mice. In the present study various steps involved during the tumor regression are examined using some biochemical and morphological parameters. During tumor regression, ascites fluid volume decreases sharply and there is an increase in carbohydrates and decrease in protein contents in the ascites supernatant after cisplatin treatment in vivo. Cisplatin treatment brings about definite changes in the arrangement/movement of surface membrane ruffles/blebs of tumor cells and causes infiltration of leukocytes (neutrophils, monocytes, lymphocytes) towards tumor cells. Membrane vesicles and vacuoles are also formed before the disintegration and lysis of tumor cells.

Animals↗

PubMed1991

Cell-cell association in ascites Dalton's lymphoma and the effect of cisplatin in vivo.

Scanning electron microscopic studies revealed that ascites Dalton's lymphoma cells are distributed singly (25-30%) or in groups of 2-3 cells (55-60%) and 5 or more cells (10-15%) connected together. The percentage of single cells and groups of 2-3 or more cells changes with tumor growth. The number of single cells is maximal 72 h after tumor transplantation. Control tumor cells revealed the presence of blebs--ruffles all over the cells. Cisplatin treatment of the cells in vivo brings about definite changes in the arrangement of blebs--ruffles over the cells. At the later stages of cisplatin treatment disintegration and breaking of the plasma membrane occurs, which ultimately results in the lysis of tumor cells.

Animals↗

PubMed1989

Effect of cisplatin on con A agglutinability of different lymphoid cells of Swiss albino rats.

Thymocytes, splenocytes, and lymph node cells showed a differential degree of agglutination which con A, which was the lowest for thymocytes and the highest for lymph node cells. Cisplatin treatment of the cells showed a gradual increase and then decrease in the degree of agglutination of the cells which varied with cisplatin concentration and time of treatment. The cells treated with 20 micrograms/ml of cisplatin for 30 min showed the maximum increase in the degree of con A agglutination. Incubation of these cisplatin-treated cells with D-xylose, D-glucose, or sialic acid before con A agglutination showed a decrease in the cell agglutinability which was the lowest for sialic acid-incubated cells. It is suggested that the removal of cell surface carbohydrate moieties after cisplatin treatment may play a role in the changes in con A agglutination of these cells.

Animals↗

PubMed1988

Effects of pollutant atmospheres on surface receptors of pulmonary macrophages.

The effects of two multicomponent pollutant atmospheres on the surface receptors (FcR) and phagocytic activity of rat pulmonary alveolar macrophages have been studied. FcR are crucial for the macrophages to become cytotoxic against target cells. The atmospheres were composed of pollutants that are prevalent in the South Coast Air Basin of southern California. Rats were exposed nose-only to a 7-component oxidant-and sulfate-containing atmosphere for 4 h/d for either 7 or 21 consecutive days. In another experiment rats were exposed 5 h/d for 5 consecutive days to another pollutant combination--acid droplets plus carbon-containing dilute diesel engine exhaust. In both experiments matched rats were exposed nose-only to purified air to be used as controls. Each of the atmospheres studied significantly reduced FcR activity for at least 3 d following the exposure, with the group of rats exposed to the 7-component atmosphere for 21 d exhibiting the most pronounced effect. Macrophages from rats exposed to the diesel exhaust plus acid atmosphere and the 7-component atmosphere for 7 d had significantly reduced phagocytic activity for at least 3 d postexposure, while the macrophages from rats exposed to the latter atmosphere for 21 d had phagocytic activity near control values. The decrease in phagocytosis and inhibition of FcR of macrophages suggests an impairment of macrophage function that probably renders the host vulnerable to bacterial and/or viral infections.

Air Pollutants↗

PubMed1985

Differential binding of conA and WGA on the cell surface, the role of sialic acid in their expression and the increased activity of sialidase after cis-Platin treatment.

It is reported that concanavalin A (conA) and wheat germ agglutinin (WGA) have a differential binding pattern on normal mouse spleen lymphocytes and the surface of Dalton's lymphoma cells. It is suggested that sialic acid on the cell surface controls the expression of lectin binding sites. Further, it has been observed that the increased release of sialic acid from cell surfaces after cis-dichlorodiammine platinum (II) (cis-Platin) treatment is due to the increased activity of sialidase.

Animals↗

PubMed1985