Biomedical subjects
Publications and source records attributed to P G Tulpule.
Known techniques were used with slight modification to analyse and quantify porphyrins in the urine samples of normal human subjects, of clinically established jaundice cases and of women taking oral contraceptives. The results indicate that the urinary porphyrin pattern can be a useful tool in the detection of early liver injury.
Erythrocyte hemolytic properties, cholesterol/phospholipid ratios, fatty acid composition, and activities of the membrane-bound enzymes (Na+, K+)- and (Ca2+, Mg2+)-ATPase were studied in male and female rats fed low erucic acid rapeseed (LEAR) and high erucic acid mustard oils (HEAM) for a period of 16 months. Rats receiving groundnut oil (GNO) served as controls. Erythrocytes from HEAM-receiving male and female rats showed increased resistance to hypotonic hemolysis. In male rats this was associated with an 85% increase (P less than 0.07) in the cholesterol/phospholipid molar ratio. The fatty acid double-bond index showed an increase in male rats receiving HEAM as well as LEAR oils. In the erythrocytes from female rats, the cholesterol/phospholipid molar ratio and double bond index remained unaffected. Specific activity of ouabain-sensitive (Na+, K+)-ATPase showed a small (+20%) but significant (P less than 0.05) increase in male but not female rats of HEAM group. Total (Na+, K+)-ATPase, ouabain-insensitive component, and (Ca2+, Mg2+)-ATPase were not altered in rats receiving LEAR or HEAM.
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Ingestion of T-2 toxin, a product of Fusarium fungi, has been reported to have a variety of effects leading to morbidity and mortality in animals and humans. Semi-purified T-2 toxin was given to monkeys by gastric intubation at a level of 100 microgram/kg body weight/day for 4-5 wk and the haematological and immune parameters were studied before and after the treatment. Leucocyte counts were depressed at the end of wk 4 of treatment. The immunological studies studies showed suppression of the bactericidal activity of neutrophils, of cell-mediated immune status as assessed by T-cell number and lymphocyte transformation, and of humoral immunity as reflected in B-cell number and IgG and IgM levels. However serum complement (CH50) did not show any change. Investigations carried out 5 months after withdrawal of the toxin indicated that these parameters had returned almost to the initial, pretreatment levels. These data suggest that the greater incidence of infection seen in mycotoxin-ingesting animals may be due to immune suppression. Withdrawal of the mycotoxin results in improvement of haematological and immune functions.
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.
Two groups of pregnant women belonging to a low socioeconomic group, one with oral lesions and the other without lesions, were studied in the 3rd trimester of pregnancy for vitamin B6 nutritional status. Both the groups showed evidence of abnormal tryptophan metabolism, and in pregnant women with clinical signs the postload xanthurenic acid excretion in urine was higher than in the other group, suggesting a severe deficiency of vitamin B6. Treatment with vitamin B6 cured the oral lesions and also corrected the abnormalities in tryptophan metabolism. Excretion of 4-pyridoxic acid was low in both the groups and more so in women with oral lesions. Administration of tryptophan load significantly elevated the excretion of 4-pyridoxic acid in urine. These results indicated that pregnant women belonging to a low socioeconomic group were, in general, deficient in vitamin B6. In pregnant women with oral lesions the deficiency of vitamin B6 was more severe than in those pregnant women without oral lesions. Whether the severity of vitamin B6 deficiency would precipitate clinical signs like oral lesions is not yet known.
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.
The susceptibility of animals to both chronic and acute aflatoxicosis is variable between species and depends upon not only the dose of the toxin and the duration of exposure but also upon the age, sex, and nutritional status of the animal. In general, acute toxicity is manifested by necrosis and cirrhosis, and chronic toxicity by carcinoma of the liver. Current research using both in vivo and in vitro studies has shown that the differences in response to aflatoxin in different animals can be attributed to their differential metabolism. The rates of metabolism and intermediate products formed are important factors in determining the type of toxic action of aflatoxin B1. According to these criteria, monkey and man are more susceptible to acute aflatoxicosis and relatively resistant to carcinogenic effects. On the other hand, animals, such as sheep and rat, are more susceptible to carcinogenic effects.
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An outbreak of a disease characterised by jaundice, rapidly developing ascites and portal hypertension associated with 20 p. 100 mortality rate was investigated in 1974. Analysis of food samples revealed that the disease outbreak was due to the consumption of maize (corn) heavily infested with the fungus Aspergillus flavus. Unseasonal rains prior to harvest, chronic drought conditions, poor storage facilities and ignorance of dangers of consuming fungal contaminated food seem to have caused the outbreak. The level of aflatoxin in food samples consumed during the outbreak was ranging between 2.5 and 15.6 microgram/g. Anywhere between 2 and 6 mg of aflatoxin seems to have been consumed daily by the affected people for many weeks. In contrast, during 1975, analysis of corn samples from the same areas revealed very low levels of aflatoxin, viz., less than 0.1 microgram/g. This was in line with the absence of major outbreak in 1975.
Male rats kept at a temperature of 4 degrees-5 degrees C were refractory to a lethal dose of aflatoxin compared to animals at 20 degrees-21 degrees C which exhibited a high mortality and marked liver damage. It is suggested that this decreased susceptibility is mediated through a stimulated microsomal drug-metabolizing system in cold environment.
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The evidences to incriminate the possible role of microsomal drug metabolizing system in aflatoxin toxicity in rat have been reviewed. It is suggested that an effective drug metabolism results in decreased acute toxicity and the products of metabolism are more carcinogenic than the native toxin to the rat liver.