Effect of dietary fish on the lipid profile of cholesterolstressed rats during copper overload.

The effect of dietary supplementation with Oil sardine (Sardinella longiceps) fish at 2/3 fat replacement, on serum lipids in the cholesterol-stressed copper loaded rats was studied. Hypercholesterolemic state observed during copper toxicity was not alleviated by sardines. Copper loading significantly decreased the triglyceride levels and the activity of ß-hydroxy ß-methyl glutaryl (HMG) CoA reductase. Fish supplementation was further effective in reducing the triglyceride levels in copper loaded rats. Significant increase in the serum phospholipid was observed in the fish supplemented rats during copper overload. The finding suggests that hypolipidemic potential of fish is certainly altered to some extent in copper toxicity since, it is well known that copper enhances the formation of free radicals. Thus it may be concluded that sardine fish is not effective in reducing the cholesterol levels during copper toxicity.

Effect of dietary fish on antioxidant parameters of normal and cholesterol stressed rats.

Feeding fish (Sardinella longiceps) to normal rats increased lipid peroxidation and total and Se-dependent glutathione peroxidase (GSH-px) activity in erythrocytes and manganese dependent superoxide dismutase (Mn-SOD) activity in liver. Feeding fish to cholesterol stressed rats showed a significant increase in the activity of GSH-px and cholesterol feeding alone, resulted in a significant increase in the lipid peroxidation and liver Mn-SOD activity. The results suggest that the high polyunsaturated fatty acid content of S. longiceps, the fish abundantly available in the west coast of India, does not have any deleterious effect by way of free radical generation. The observed lipid peroxidation is not critical as is evident from the results of glutathione level and other scavenging enzymes.

Genotoxicity of lynoral (ethinyloestradiol, an oestrogen) in mouse bone marrow cells, in vivo.

The genotoxic effect of Lynoral (ethinyloestradiol, an oestrogen) was studied using mouse bone marrow cells treated in vivo, employing a chromosomal aberration assay and micronucleus test. The dose and time-yield effects of the sex hormonal drug were investigated. Lynoral failed to induce significant genetic damage in the bone marrow erythrocytes of mice, regarding chromosomal aberrations and micronuclei.

Effect of Ziram, Thiram, and Dithane M-45 on bone marrow cells of mice-assessed by micronucleus test.

Micronucleus test is an extensively used protocol to assess the mutagenicity of environmental chemicals. This was developed by Schmid and his co-workers (Matter and Schmid, 1971; Ledebur and Schmid, 1973). The micronucleus test is simple, quick and as sensitive as the chromosome aberration analysis. It is based on the principle that during anaphase, acentric chromatid and chromosome fragments lag behind, where as centric elements move towards the spindle pole. After telophase both the undamaged chromosomes and the centric fragments give rise to the daughter nuclei. The lagging elements are transferred into one or several secondary nuclei, which are as a rule much smaller than the main nucleus, and therefore called micronucleus (Schmid, 1973). The clastogenic effect of various chemicals is measured by micronucleus test. Erythrocytes are two types, the younger ones are polychromatic erythrocytes (PCE), which stain bluish and the older, the normo chromatic erythrocytes (NCE) which stain reddish. A few hours after the completion of last mitosis the erythroblasts expel their nucleus for unknown reasons and the micronucleus alone remains in the cytoplasm of the Polychromatic erythrocytes, and they are easily recognisable. Erythrocyte micronucleus represents the consequence of chromosomal aberrations induced during preceding mitotic division of erythrocytes (Matter and Grauwiler, 1974).

Toxicological effects of ziram, thiram, and dithane M-45 assessed by sperm shape abnormalities in mice.

The three commonly used dithiocarbamate fungicides ziram, thiram, and dithane M-45 were investigated for their mutagenic and carcinogenic potency using sperm shape abnormalities in mice. The fungicides were administered intraperitoneally in single and cumulative doses. All three of the fungicides tested were found to induce significant increase in the frequency of abnormal sperm at all the doses, and a linear dose effect was observed.

In vivo genotoxic effects in mice of Metacid 50, an organophosphorus insecticide.

The genotoxic effect of methyl parathion, an organophosphorus insecticide commercially available as Metacid 50, was studied in Swiss albino mice using bone marrow and peripheral blood micronucleus tests. Single acute oral doses of the insecticide at concentrations of 75.0, 37.5, 18.75 and 9.375 mg/kg body weight, equivalent to 1/2 LD50, 1/4 LD50, 1/8 LD50 and 1/16 LD50, administered to female mice, elicited positive responses in bone marrow and peripheral blood micronuclei tests. Statistically significant increases in the frequency of micronuclei were observed at higher doses in both the tests performed. The data obtained for our experiments suggest that methyl parathion is a potent mutagen and so it is also likely to have a genotoxic effect in humans.

Cytogenetic effects of ribavirin on mouse bone marrow.

The micronucleus test and mitotic chromosome analysis were used to study the in vivo mutagenic activity of ribavirin on bone marrow cells of Swiss albino mice. To determine the incidence of micronuclei, mice were injected i.p. twice, at an interval of 24 h. with the drug at doses of 20, 100 and 200 mg/kg. Animals were killed 6 h after the second dose and bone marrow was examined for the presence of micronuclei in developing erythrocytes. Ribavirin significantly (P less than 0.05) induced micronuclei in polychromatic erythrocytes at all doses. A study was conducted to investigate the cytogenetic effect of the drug on mitotic chromosomes. Ribavirin at 200 mg/kg/day was administered to mice for 3 and 5 days. Repeated treatment with the high dose of ribavirin produced a highly significant (P less than 0.02) increase in abnormal metaphase spreads. The results indicate that ribavirin is mutagenic to bone marrow cells of mice as evaluated by the micronucleus test and by chromosome analysis.

UV-induced chromosome aberrations, sister-chromatid exchanges and cell survival in cultured lymphocytes from malnourished children.

Cultured lymphocytes from children with kwashiorkor and from normal children were examined for their susceptibility to ultraviolet (UV)-induced chromosome aberrations, sister-chromatid exchanges and cell survival. Cells from kwashiorkor exhibited increased chromosome aberrations, but not sister-chromatid exchanges, when exposed to higher doses of UV. Furthermore, when cells from these patients were exposed to higher doses of UV, there was a significant reduction in viability. These results indicate that, as compared to normals, cells from kwashiorkor were more sensitive to the lethal effects of UV.

Lymphocyte proliferation kinetics in malnourished children measured by differential chromatid staining.

1. Utilizing the bromodeoxyuridine differential-chromatid labelling technique the in vitro proliferation of lymphocytes from children with kwashiorkor was followed in phytohaemagglutinin-stimulated cultures and compared with controls. 2. Analyses of first, second and third or subsequent division cells as a function of culture time between 40 and 96 h showed that cell-cycle duration was prolonged in kwashiorkor cultures. The extent of this increase was approximately 4.5 h for the first-division cells and 1.5 h for third-division cells. 3. The peak for second-division cells was depressed in kwashiorkor cultures. 4. A decreased number of third or subsequent-division cells was observed in kwashiorkor cultures at all time points studied. 5. These findings suggest that the loss in lymphocyte activity to PHA in malnourished children in general could be due to an increase in cell-cycle duration of responding lymphocytes.