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Biomedical subjects

S A Tepper

Publications and source records attributed to S A Tepper.

At least 37 records · Page 2Linked to original sources
PubMed1984

Diet, nutrition intake, and metabolism in populations at high and low risk for colon cancer. Comparison of serum hexosaminidase levels.

Elevated levels of serum hexosaminidase (beta-2-acetamido-2-deoxy-D-glucoside; N-acetamidodeoxy-D-glucohydrolase, EC 3.2.1.30)(HEX) have been found in patients with cancer. In view of the reported low levels of colon cancer among Seventh-day Adventists (SDA) we determined levels of total HEX, and its heat-labile (HEX-A) and heat-stable (HEX-B) isozymes in vegetarian SDA, lacto-ovo vegetarian SDA, nonvegetarian SDA, and the general public. Lowest levels of total HEX and highest percentage of HEX-B were found in vegetarian SDA. The levels in the other three groups were comparable, and these differences were seen at all age levels. Female subjects exhibited significantly lower total HEX levels than the males but the percentage of HEX-B was the same.

Adult↗
PubMed1984

Serum hexosaminidase as a possible biomarker for human cancer.

The levels of total serum hexosaminidase and of its heat stable isozyme (beta-hexosaminidase) were determined in the sera of subjects bearing ovarian and other female genital cancers and of control subjects. The assays were carried out on a double blind basis. Total hexosaminidase levels were significantly elevated in sera of subjects with female genital cancers and in subjects with ovarian cancer. Levels of beta-hexosaminidase were elevated in all subjects with genital cancer. The hexosaminidase assay may be a convenient biomarker for human cancer since earlier studies have shown that total and beta-hexosaminidase levels are elevated in sera of most cancer patients studied.

Female↗
PubMed1983

Influence of dehydroepiandrosterone (DHEA) on cholesterol metabolism in rats.

Wistar rats were fed semipurified diets containing 0.5% of dehydroepiandrosterone (DHEA) for 14 days. DHEA feeding resulted in weight loss and slight liver enlargement. It did not affect serum triglyceride levels but increased serum cholesterol levels. Liver triglyceride levels of DHEA-fed rats were significantly lower than in controls. DHEA inhibited cholesterol absorption. Liver slices from DHEA-fed rats incorporated more acetate into cholesterol than controls; there were no differences in conversion of mevalonate.

Animals↗
PubMed1983

Modification of dimethylhydrazine-induced carcinogenesis in rats by dietary cholesterol.

Diets capable of affecting serum cholesterol levels were examined for effects on tumorigenesis in male Fischer 344 rats given 1,2-dimethylhydrazine dihydrochloride (DMH). Four regimens were used: Group A was maintained on a semipurified diet; Group B was maintained on the same diet with cholesterol and bile salts added; Group C was fed the cholesterol and bile salt diet and then switched to the semipurified diet; and Group D was fed the cholesterol and bile salt diet and then placed on a semipurified diet containing bile salts. Six months after DMH administration, Group B and D exhibited similar tumor incidence (77% and 83%, respectively) and yield (2.3 and 2.4 tumors/tumor-bearing rat). These yields were significantly greater than those seen in Group A (70% incidence and 1.4 tumors/tumor-bearing rat) or Group C (52% incidence and 1.7 tumors/tumor-bearing rat). Tumors in Groups B and D were larger in size and closer to the rectum than those seen in the other groups. In each of Groups A, C, and D, approximately 26% of the tumors were malignant; in Group B, 42% were malignant. Colonic epithelial cell kinetics in rats from Groups C and D not given DMH were determined using autoradiographic study of [3H]thymidine incorporation. Group D showed enhanced cell proliferation and expansion of the crypt cell population. These results suggest that dietary bile salts increase cell turnover and frequency of tumors, and that the addition of cholesterol to a cocarcinogenic diet can be associated with a significantly higher percentage of invasive tumors.

1,2-Dimethylhydrazine↗
PubMed1983

Influence of beclobrate and eniclobrate on cholesterol metabolism in rats.

Two new hypocholesterolemic compounds, ethyl-(+/-)-2-[[alpha-(p-chlorophenyl)-p-tolyl]-oxy]-2-methylbutyrate (Sgd 24 774, beclobrate) and the 3-pyridinylmethyl ester (eniclobrate), have been studied in normocholesterolemic rats. The two compounds are hepatomegalic and they lower serum and liver cholesterol levels but raise liver triglyceride levels. They also reduce the percentage of esterified cholesterol present in the serum. Beclobrate enhances hepatic HMG-CoA reductase activity but does not affect cholesterol-7 alpha hydroxylase. Eniclobrate, on the other hand, increases activity of the hydroxylase but not of HMG-CoA reductase. Neither compound affects cholesterol absorption.

Animals↗
PubMed1982

Experimental atherosclerosis in rabbits fed cholesterol-free diets.

Rabbits were fed a semipurified, cholesterol-free atherogenic diet containing 40% sucrose, 25% casein, 14% fat, 15% fiber, 5% salt mix and 1% vitamin mix. The fats were corn oil (CO), palm kernel oil (PO), cocoa butter (CB), and coconut oil (CNO). The rabbits were bled at 3, 6, and 9 months and killed at 9 months. Serum lipids of rabbits fed CO were unaffected. Serum cholesterol levels (mg/dl) at 9 months were: CO -- 64; PO -- 436; CB -- 220; and CNO -- 474. HDL-cholesterol (%) was: CO -- 37; PO -- 8.6; CB -- 25.1; and CNO -- 7.0. Average atherosclerosis (arch + thoracic/2) was: CO -- 0.15; PO -- 1.28; CB -- 0.53; and CNO -- 1.60. Cocoa butter (iodine value 33) is significantly less cholesterolemic and atherogenic than palm oil (iodine value 17) or coconut oil (iodine value 6). The difference between the atherogenic effects of cocoa butter and palm oil may lie in the fact that about half of the fatty acids of palm oil are C 16 or shorter, whereas 76% of the fatty acids of cocoa butter are C 18 or longer.

Animals↗
PubMed1981

Age-strain interrelations in lipid metabolism of rats.

Various aspects of lipid metabolism were compared in Fisher 344 (F) and Sprague-Dawley (SD) rats aged 2, 6, 12, 18 and 24 months. The analyses included free and total cholesterol of serum and liver, LCAT, hepatic HMG-CoA reductase, cholesterol 7 alpha-hydroxylase, fatty acid synthetase, acetyl CoA carboxylase and cholesterol synthesis from acetate or mevalonate. The body weight of SD rats increases with age whereas that of F rats plateaus at 9-12 months. Liver and aorta cholesterol levels were comparable for the 2 strains. Serum cholesterol varied but was usually lower in F rats. HMG-CoA reductase and cholesterol 7 alpha-hydroxylase activities were not significantly different. Cholesterol synthesis from acetate was significantly higher only in 2-month-old F rats; synthesis from mevalonate was similar at each level. Acetyl CoA carboxylase and fatty acid synthetase activity were generally higher in F rats at every age level. The major difference between F and SD rats is in their pattern of weight gain with age. Differences in lipid metabolism are most marked between the young (2-month) rats.

Aging↗
PubMed1981

Experimental atherosclerosis in rabbits fed cholesterol-free diets. Part 9. Beef protein and textured vegetable protein.

Rabbits were fed a semipurified diet containing 40% sucrose, 25% protein, 15% fiber and 14% tallow. The proteins fed were beef (B), textured vegetable protein (TVP) and casein (C). One diet contained beef-TVP (1 : 1) and in another a soy carbohydrate fraction, spent flakes, was added to the diet; it provided 2.2% protein and 10.5% fiber. TVP provided 6.4% soluble carbohydrate and 10.5% fiber. The diets were fed from 8 months. Diets containing beef protein or casein gave significantly higher serum cholesterol levels and atherosclerosis and significantly lower serum HDL-cholesterol than did the other 3 diets. The beef-TVP (1 : 1) diet gave low serum cholesterol (67% below beef) levels and atherosclerosis (47% below beef). This effect is probably due to the protein. The diet containing spent flakes gave low serum cholesterol levels (44% below beef) and atherosclerosis (45% below beef). This effect is attributed to the different fiber. The lowest serum cholesterol levels and least severe atherosclerosis were observed in the rabbits fed TVP.

Animals↗
PubMed1979

Influence of whole or skim milk on cholesterol metabolism in rats.

Male Wistar rats were fed commercial ration and given whole milk, skim milk, or water to drink. After 3 weeks the control group showed the greatest weight gain. Rats given whole milk had the smallest livers. Serum cholesterol levels were significantly lower in rats fed either whole or skim milk, but other serum lipids were unaffected. Liver triglyceride levels were lowest in the rats on skim milk. Activities of hepatic fatty acid synthetase, hydroxymethyl-glutaryl coenzyme A reductase and cholesterol 7alpha-hydroxylase were similar in the two milk-fed groups and considerably lower than in the controls.

Animals↗