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Biomedical subjects

R Chander

Publications and source records attributed to R Chander.

At least 37 records · Page 2Linked to original sources
PubMed1992

Role of free radicals in Plasmodium berghei infected Mastomys natalensis brain.

Lipid peroxide, lipid hydroperoxide, reduced glutathione, oxidised glutathione, lipofuscin contents and the activity of the enzyme superoxide dismutase were assessed in P. berghei infected M. natalensis brain. The results showed significant increase in the levels of lipid peroxides, lipid hydroperoxides and lipofuscin in brain subcellular fractions of P. berghei infected M. natalensis. Furthermore, a depressed superoxide dismutase activity was observed along with regulation in glutathione content. An elevated level of lipid peroxidation products along with depressed activity of scavengers in brain during malaria highlights the role of free radicals in malarial pathology.

Animals↗
PubMed1992

Effect of picroliv on glutathione metabolism in liver and brain of Mastomys natalensis infected with Plasmodium berghei.

Administration of picroliv, the active principle from Picrorhiza kurrooa, at a dose of 6 mg/kg, po for two weeks showed significant protection against changes in liver and brain glutathione metabolism of Plasmodium berghei infected Mastomys natalensis. The depletion of reduced glutathione level and inhibition of glutathione-S-transferase, glutathione reductase and glutathione peroxidase activities due to P. berghei infection were markedly recovered by picroliv. The increased levels of lipid peroxidation products in damaged tissues were also reduced along with the recovery of glutathione metabolism.

Animals↗
PubMed1992

Hypolipidemic activity of Achyranthus aspera Linn in normal and triton induced hyperlipemic rats.

The alcoholic extract of A. aspera, at 100 mg/kg dose lowered serum cholesterol (TC), phospholipid (PL). triglyceride (TG) and total lipids (TL) levels by 60, 51, 33 and 53% respectively in triton induced hyperlipidemic rats. The chronic administration of this drug at the same doses to normal rats for 30 days, lowered serum TC, PL, TG and TL by 56, 62, 68 and 67% respectively followed by significant reduction in the levels of hepatic lipids. The faecal excretion of cholic acid and deoxycholic acid increased by 24 and 40% respectively under the action of this drug. The possible mechanism of action of cholesterol lowering activity of A. aspera may be due to rapid excretion of bile acids causing low absorption of cholesterol.

Animals↗
PubMed1991

Age-related elevation of lipid peroxidation products: diminution of superoxide dismutase activity in the central nervous system of rats.

Alteration in lipid peroxidation products such as lipid peroxides, lipid hydroperoxides were studied in different regions of CNS of ageing rats (13, 26, 52, 78 and 104 weeks). The levels of lipid peroxide and lipid hydroperoxide were increased in various regions of brain and spinal cord. However, the activity of superoxide dismutase was decreased in cerebrum, hypothalamus, hippocampus, cerebellum, brain stem and spinal cord. The present communication demonstrates that the different parts of CNS at 13 and 26 weeks of age have lipid peroxidation products different from that of 104-week-old rats.

Aging↗
PubMed1990

High density lipoprotein is a scavenger of superoxide anions.

Present work describes a new property of HDL to act as a scavenger of O2- free radicals in vitro. This lipoprotein prevents both enzymic and non-enzymic generation of O2- anions as evidenced by inhibition of xanthine oxidase, peroxidase, peroxidation of pyrogallol and phenazine methosulphate-NADH reaction. Ascorbate stimulated MDA formation in microsomes has been shown to be suppressed by HDL and these effects are comparable with that of BHA.

Animals↗
PubMed1990

Molecular basis of hyperlipidemia in golden hamsters during experimental infection with Ancylostoma ceylanicum (Nematoda:Strongylidae).

An infection of golden hamsters with Ancylostoma ceylanicum, a hookworm parasite, induced profound hyperlipidemia, particularly hypertriglyceridemia, and the effect was directly related to the degree of infection. A significant increase was also noticed in serum cholesterol and phospholipid levels. The appearance of lipoprotein-X, an abnormal low density lipoprotein, was detected in the serum of hookworm-infected animals. The hyperlipidemia was further characterized by an increase in very low density lipoproteins (VLDL) and low density lipoproteins (LDL) with a concomitant decline in high density lipoproteins (HDL). Decreased lipolytic activities, especially triglyceride lipase, in hepatic tissue and induction of lipolytic activities in intestine and adipose tissues indicated mobilization of fats from adipose and jejunum with a defective removal of triglyceride-rich lipoproteins in hepatic tissues. Accumulation of lipids in liver and depletion in adipose tissue supported these results. The derangement may have a significant effect on host parasite interaction and is an important pathophysiological feature occurring during experimental ancylostomiasis.

Ancylostomiasis↗
PubMed1990

Evaluation of hepatoprotective activity of picroliv (from Picrorhiza kurroa) in Mastomys natalensis infected with Plasmodium berghei.

Administration of picroliv, a standardized fraction of alcoholic extent of Picrorhiza kurroa (3-12 mg/kg/day for two weeks) simultaneously with P. berghei infection showed significant protection against hepatic damage in Mastomys natalensis. The increased levels of serum glutamate oxaloacetate transaminase (GOT), glutamate pyruvate transaminase (GPT), alkaline phosphatase, lipoprotein-X (LP-X) and bilirubin in the infected animals were marked reduced by different doses of picroliv. In the liver, picroliv decreased the levels of lipid peroxides and hydroperoxides and facilitated the recovery of superoxide dismutase and glycogen. Picroliv had no effect on the degree of parasitaemia.

Animals↗
PubMed1990

Hepatic superoxide dismutase, catalase and lipid peroxidation products in Mastomys natalensis infected with Plasmodium berghei.

P. berghei infection in M. natalensis caused a significant reduction in the hepatic SOD and catalase activities. Cu-Zn SOD was more susceptible to infection than Mn SOD. The inhibition of enzyme activities was associated with marked increase in the levels of lipid peroxides, lipid hydroperoxides and conjugated dienes in infected M. natalensis. The alterations in the hepatic SOD, catalase and lipid peroxides are related with the severity of infection.

Animals↗
PubMed1990

Hepatoprotective activity of picroliv against carbon tetrachloride-induced liver damage in rats.

Administration of carbon tetrachloride to normal rats increased activities of hepatic 5(1)-nucleotidase, acid phosphatase, acid ribonuclease while the activities of succinate dehydrogenase, glucose 6-phosphatase, superoxide dismutase and cytochrome P450 were decreased. Levels of lipid peroxides, total lipids and cholesterol of liver were also increased. The activities of serum glutamate oxaloacetate transaminase, glutamate pyruvate transaminase and alkaline phosphatase were increased. Other serum parameters showing changes after carbon tetrachloride were: bilirubin, proteins, cholesterol, triglycerides and lipoprotein-X. Picroliv (from the plant Picrorhiza kurroa) in doses of 6 and 12 mg/kg provided a significant protection against most of the biochemical alterations produced by carbon tetrachloride. The degree of protection afforded by picroliv, when administered simultaneously or as a pretreatment was almost equal.

Animals↗
PubMed1989

Condylomata lata of the eyelids.

A patient with secondary syphilis and extensive condylomata lata on the face, neck, axillae, groins, and genitalia is described. His facial condylomata lata affected the eyelids, medial canthus, nasolabial folds, angles of the mouth, and chin. Condylomata lata of the eyelids has not been described previously.

Adult↗
PubMed1989

Hepatoprotective activity of silymarin against hepatic damage in Mastomys natalensis infected with Plasmodium berghei.

Silymarin, a flavolignan from the seeds of Silybum marianum, showed significant hepatoprotective activity in P. berghei-induced hepatic damage in M. natalensis, as assessed by changes in several serum and liver biochemical parameters. Changes in lipoprotein-X, GOT, GPT, alkaline phosphatase and bilirubin were found to be protected by silymarin at different doses. Maximum activity was observed at a dose of 5 mg/kg bw, po. Silymarin had no effect on parasitaemia.

Animals↗
PubMed1989

Hepatic low density lipoprotein receptor binding and lipid profile in Mastomys natalensis during Plasmodium berghei infection.

Plasmodium berghei infection to Mastomys natalensis showed hyper beta-lipoproteinemia. The increase in serum cholesterol is associated with decreased uptake of low density lipoprotein (LDL) by the liver through receptor mediated endocytosis. The membranes prepared from infected M. natalensis exhibit up to 50% decline in high affinity binding sites for human 125I-LDL. Significant increases in serum lipids, cholesterol, triglyceride and lipid peroxide (LPO) contents of liver membrane were observed. Effects of lipid constituents and LPO content of liver membrane in relation to LDL catabolism and other possible mechanisms have been explained.

Animals↗
PubMed1987

Mechanisms of acquired resistance in mouse typhoid.

A polyvalent radiovaccine of Salmonella was shown to induce protective immunity in mice. The results revealed that the immunized mice progressively eliminated the challenged organisms and no Salmonella could be isolated after a period of 21 days. In contrast, Salmonella grew in the control mice and reached levels of 10(8) to 10(9) cfu/spleen resulting in the death of animals. Sera from both control and the immune mice were found to lack bactericidal activity. It was further observed that the vaccine induced delayed type of hypersensitivity and that antibody production as measured by bacterial agglutination and passive hemagglutination were low in response to the vaccine. However, the phagocytic activity of the reticuloendothelial system was considerably enhanced by the immunization. The results of experiments with immunosuppressed mice suggested the role of thymus derived (T) lymphocytes in the protection.

Agglutination Tests↗
PubMed1986

Role of thymus-derived lymphocytes in acquired immunity to salmonellosis in mice.

The relative role of thymus-derived (T-) lymphocytes and bone marrow-derived (B-) cells in acquired immunity to salmonellosis was examined in mice. The results demonstrate that the protective capacity of the donor immunized mice could be passively transferred to the recipient mice by spleen cells but not with peritoneal exudate cells or sera. A high cell number of spleen cells (2 X 10(8)/mouse) were required before passive transfer of immunity could be obtained. Of the T-lymphocytes and B-cell populations of spleen cells, T-cells from immune mice were effective in conferring protection to the recipient mice.

Animals↗
PubMed1981

Induction of resistance to ascites tumor in mice with MFS-180 cells treated with glutaraldehyde, lipopolysaccharide, and concanavalin A.

Immunization with MFS-180 vaccine prepared in the presence of glutaraldehyde (0.05%), lipopolysaccharide (LPS) (100 micrograms/ml), and concanavalin A (Con A) (200 micrograms/ml) could protect Swiss mice against a subsequent challenge by 1 X 10(6) MFS-180 cells. The sequence of attachment of LPS and Con A to glutaraldehyde-treated cells as found to determine the efficacy of the vaccine. LPS coupled with glutaraldehyde-treated cells before Con A could effect 100% survival, while LPS attached after Con A treatment to glutaraldehyde-treated cells showed only 60% survival. The protection was specific for syngeneic cells.

Aldehydes↗
PubMedDate not supplied

(Patho)physiologic pathways to drug targeting: artificial viral envelopes.

The goal of this study was to exploit molecular recognition of cell surface receptors by viral surface glycoproteins as a means for the selective intracellular delivery of macromolecules. To accomplish this, artificial viral envelopes (AVE) resembling the human immunodeficiency virus-1 (HIV-1) were designed as a model system. Recombinant HIV-1 surface glycoprotein gp160 (HIV-1 rgp160) was inserted in the artificial envelope by a two-step detergent dialysis process. The artificial HIV-1 envelope recognized the CD4 cell surface receptor. FITC-dextran and ricin A were employed as model macromolecules as they cannot passively diffuse across cell membranes. Selective transfer of FITC-dextran encapsulated in HIV-1 rgp160 AVE into a CD4-positive cell line (REX-1B) versus a CD4-negative cell line (KG-1) was demonstrated. Ricin A at concentrations as low as 2 ng/ml arrested cell growth of CD4-positive MOLT-4 cells, whereas 8 ng/ml ricin A in solution had no effect on cell growth. The arrest of cell growth was reverted in the presence of excess anti-gp120 monoclonal antibody. Naked envelopes (without HIV-1 rgp160 inserted) were also found to interact with cells and transfer material, although less efficiently and in a non-specific manner. Viral mimicry using AVE may be a means for targeted intracellular delivery of peptides, proteins, enzymes, toxins, oligodeoxynucleotides, gene constructs, and other non-diffusive, labile or toxic macromolecules.

CD4 Antigens↗