Carcinogenicity examination of betel nuts and piper betel leaves

Summary A dry powder of betel nuts, piper betel leaves and lime was administered to rats. Epidermal thickening was frequently observed in the upper digestive tracts of rats in groups fed the betel nut diet mixed with lime and the betel leaves diet, and a forestomach papilloma was seen in 1 rat given betel leaves diet. These epidermal changes were scarcely seen in rats given either betel nut or normal diet alone.This work was supported by a grant from the U.S.-Japan Cooperative Medical Science Program     

Stabilisation of collagen by betel nut polyphenols as a mechanism in oral submucous fibrosis

Treatment of reconstituted collagen fibrils and pieces of rat dermis with the crude extract, purified tannins or (+)-catechin from betel nut (Areca catechu) increases their resistance to both human and bacterial collagenases in a concentration-dependent manner. These tanning agents may stabilise collagen in vivo following damage to the oral epithelium, and promote the sub-epithelial fibrosis which occurs in betel nut chewers.     

Stabilisation of collagen by betel nut polyphenols as a mechanism in oral submucous fibrosis

Summary Treatment of reconstituted collagen fibrils and pieces of rat dermis with the crude extract, purified tannins or (+)-catechin from betel nut (Areca catechu) increases their resistance to both human and bacterial collagenases in a concentration-dependent manner. These tanning agents may stabilise collagen in vivo following damage to the oral epithelium and promote the sub-epithelial fibrosis which occurs in betel nut chewers.     

Betel nut residues in archaeological samples of human teeth from the Mariana Islands

Two tetrahydropyridine alkaloids, arecaidine and guvacine that are characteristic of betel nut (Areca catechu L.) have been detected in the deliberately stained labial surface of female teeth excavation on Rota, Mariana Islands. This was accomplished using selected ion monitoring techniques in conjunction with gas chromatography/electron impact-mass spectrometry. These alkaloids were not present on the buccal surface of the teeth and indicate the use of betel nut to effect the staining.     

Experimental liver fibrosis induced in rats receiving high doses of alcohol and alternating between regular and vitamin-depleted diets

Liver fibrosis was induced in rats by simulating human alcoholic eating and drinking patterns. Alcohol addiction was established by gradually increasing the ethanol concentration in the drinking water; salts were added at the terminal stage. The hepatocytes of rats receiving alcohol concentrations exceeding 50% (v/v) (similar to vodka) exhibited alcoholic hyaline (Mallory bodies). Alcoholic liver fibrosis was induced by alternating between regular and autoclaved (vitamin-depleted) diets, simulating the irregular eating habits of human alcoholics. In the livers of rats receiving 70% (v/v) ethanol (comparable to absinthe) with 25% saline and fed the alternating diets, pericellular fibrosis was induced. No significant difference in calorie intake between control and alcohol rats was detected except when rats underwent drinking bouts (heavy drinking phase). This indicates that neither a high-fat diet nor a choline-depleted diet is necessary to induce the alcoholic fibrosis seen in human alcoholics.     

Reproductive consequences of mega vitamin E supplements in female rats

Summary Female rats fed 0, 25, 2500 and 10,000 IU vitamin E/kg diet for 3 months were examined for reproductive performance. On 10,000 IU vitamin E/kg diet, the fertility of inseminated rats was significantly reduced as compared to rats given normal or nutritional levels of vitamin E.This work was supported by research grants from the National Research Council of Canada and the Research Committee of The University of British Columbia. We thank Mrs Virginia Green for her help in statistical analysis. Reprint requests should be addressed to Dr I. D. Desai, Professor of Nutrition.     

Hypolipidemic effects of garlic oil in rats fed ethanol and a high lipid diet

Summary Feeding of ethanol and a high fat-high cholesterol diet to rats markedly increased the total lipids in the liver, and cholesterol and triglyceride levels in the serum, liver and kidneys. However, when ethanol mixed with 0.5% garlic oil was fed to animals maintained on the high fat-high cholesterol diet, these lipid levels were significantly reduced to levels near to those seen in untreated control rats. Garlic oil did not reduce the serum albumin or the total proteins of liver, kidneys or serum when fed along with ethanol. Probably the garlic oil enhances the catabolism of dietary cholesterol and fatty acids.The authors acknowledge with thanks the financial assistance of the University of Maiduguri for carrying out this project.     

Naloxone and intestinal motility

Summary It was supposed that the inhibition of intestinal peristalsis seen in animals and humans after abdominal surgery might be related to the release of endorphins, endogenous opiate receptor agonists, caused by the surgical stress and pain. However, naloxone, a potent morphine and endorphin antagonist, failed to block this peristaltic inhibition in rats, which leaves the mechanism of this inhibition, and thus the function of intestinal endorphins, still very much in doubt.     

Naloxone and intestinal motility.

It was supposed that the inhibition of intestinal peristalsis seen in animals and humans after abdominal surgery might be related to the release of endorphins, endogenous opiate receptor agonists, caused by the surgical stress and pain. However, naloxone, a potent morphine and endorphin antagonist, failed to block this peristaltic inhibition in rats, which leaves the mechanism of this inhibition, and thus the function of intestinal endorphins, still very much in doubt.     

Effect of the type of diet on the distribution of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase in rat small intestine

Summary The jejunoileal gradient for the HMG-CoA reductase activity in the microsomal fraction of the epithelial cells of the small intestine of rats given commercial pellets was reserved within a few days after changing the ration to a semipurified diet. The response of the reductase was essentially the same in villus and crypt cells.     

外源性干细胞因子对糖尿病胃轻瘫大鼠胃窦Cajal细胞的影响

目的探讨外源性干细胞因子（SCF）能否改善糖尿病胃轻瘫（DGP）大鼠胃窦Cajal细胞（ICC）的异常病变。方法sD大鼠随机分为实验组和对照组，实验组腹腔注射链脲佐菌素（STZ）50mg／kg并高糖高脂饲料不规律喂养构建DGP模型，对照组腹腔注射等量生理盐水并普通饲料规律喂养。成模后随机分为糖尿病组（DM组）、糖尿病＋外源性干细胞因子治疗组（DM＋SCF组）；DM＋SCF纽腹腔注射SCF0．4ug／（kg·d），共15天，对照组和DM纽每天腹腔注射等量的磷酸盐缓冲液（pH=7．4）。RT-PCR、Wester Dblot检测胃窦组织中SCF及c—kit的mRNA及蛋白表达；免疫组化、透射电镜观察胃窦组织中Cajal细胞的变化。结果DM组大鼠胃窦组织SCF及c—kit的mRNA及蛋白表达下降，Cajal细胞数量减少，细胞内线粒体肿胀、内质网扩张；予外源性SCF干预后，胃窦组织中SCF及C—kjf的mRNA及蛋白表达上调，caial细胞数量增多、超微结构明显改善。结论外源性SCF能在一定程度上改善或逆转糖尿病胃轻瘫大鼠胃窦Cajal细胞的异常病变：     

Vitamin D and reproduction in Wistar rats]

Females have received from weaning a semi-synthetic diet (0,35% Ca; 0,32% P; 0,03% Mg), with or without vitamin D (+/- D). Fertility of these females was not changed. At weaning, the young from mothers--D had lower weight, calcemia and phosphatemia, but the ash content of the femur was the same as for young from mothers + D. Young rats from mothers +/- D were given the diet with or without vitamin D. 19 days after weaning, the diet of the mother (+/- D) appears to be the principal factor for growth, calcemia and the ash content of the femur; the diet of the young (+/- D) produced only slight differences between ash contents.     

Lack of effect of butylated hydroxytoluene on dimethylhydrazine-induced colon carcinogenesis in rats.

Rats were given 6600 ppm of butylated hydroxytoluene (BHT) in the diet along with 10 weekly oral doses of dimethylhydrazine (DMH, 30 MG/KG). The incidence and mean number of colonic tumors produced were similar to that of rats given DMH alone. Thus, BHT did not provide any protective effect against colon carcinogenesis.     

Parenteral feeding abolishes the circadian adrenocortical rhythm in rats

Summary The circadian rhythm of the blood corticosterone level disappeared in rats that had been given a liquid diet i.v. during a resticted time of day for 10 days, suggesting an important role of the oro-gastrointestinal tract in formation of the rhythm.     

Effects of oral contraceptive steroids (norethisterone/mestranol) on the activities of hepatic drug-metabolizing enzymes in iron-deficient anemic rats

Either oral contraceptive steroid (norethisterone/mestranol; N/M) treatment or iron-deficiency (Fe(-] anemia alone caused an increase in NADPH cytochrome c reductase and in three hepatic microsomal mixed-function oxidase activities in female rats. When N/M treatment and the Fe(-) diet are combined, no further change in hepatic enzyme activity is seen compared with that with either treatment alone.     

Effects of theophylline on chemically induced liver tumorogenesis and on bladder membranes in rats]

The addition of theophylline to the diet of rats given the carcinogen 4-dimethylaminoazobenzene did not significantly impair the development of hepatomas. In contrast, the feeding of theophylline has been associated to some histopathological changes in bladder membrane leading to the occurrence of malignant papillomas.     

Ovarian stimulation by exogenous gonadotrophins in fetal ethanol-exposed immature rats

Summary Adult pregnant rats were given either an ad libitum liquid diet containing 5% ethanol, a pair fed liquid diet or an ad libitum diet of rat chow and water administered throughout pregnancy and during the nursing period. The female offspring received either pregnant mare's serum gonadotrophin (PMSG) or PMSG followed by human chorionic gonadotrophin (hCG) at 30 days of age. The ovaries of fetal ethanol-exposed animals responded greater to the exogeneous gonadotrophins with enhanced ovarian weights, increased numbers of ova shed, greater numbers of corpora lutea and antral follicles, and higher serum progesterone levels than in animals exposed to the control diets during gestation.     

Ovarian stimulation by exogenous gonadotrophins in fetal ethanol-exposed immature rats

Adult pregnant rats were given either an ad libitum liquid diet containing 5% ethanol, a pair fed liquid diet or an ad libitum diet of rat chow and water administered throughout pregnancy and during the nursing period. The female offspring received either pregnant mare's serum gonadotrophin (PMSG) or PMSG followed by human chorionic gonadotrophin (hCG) at 30 days of age. The ovaries of fetal ethanol-exposed animals responded greater to the exogenous gonadotrophins with enhanced ovarian weights, increased numbers of ova shed, greater numbers of corpora lutea and antral follicles, and higher serum progesterone levels than in animals exposed to the control diets during gestation.     

Hepatic phosphatidylcholine synthesis in deficiency of lysine and threonine: effect of malathion

Rats fed on a rice diet deficient in lysine and threonine showed increased activities of CDP-Choline pathway enzymes and incorporation of (methyl-3H)-choline into hepatic microsomal phosphatidylcholine, compared to rats fed on the same diet supplemented with lysine and threonine. However, the amount of microsomal phosphatidylcholine was significantly decreased in rats fed a deficient rice diet. These results suggest an enhanced phosphatidylcholine catabolism in rats fed on a rice diet deficient in lysine and threonine. Malathion administration reduced the amount of phosphatidylcholine in all the groups.     

Dietary induced increase of lactase activity in adult rats is independent of adrenals

Adult rats fed 10 days a low starch-high fat diet were either adrenalectomized or sham-operated and force-fed the same diet another 5 days; 14 h before sacrifice, some animals were force-fed a sucrose diet. Activity of lactase, sucrase and maltase was increased in adrenalectomized and sham-operated rats.