慢性氟中毒大鼠体氟积累排泄动态变化及硒的影响

Ｗｉｓｔａｒ大鼠饮３０和５０ｍｇ／Ｌ高氟（Ｆ）水造成慢性氟中毒，同时另外两组大鼠饮高Ｆ水、饲２ｍｇ／ｋｇ加硒（Ｓｅ）饲料。１年内每月测饮水、摄食和排尿量，而后计算其日平均摄Ｆ、排Ｆ量，并每月测尿液Ｆ含量。喂养至４、８、１４个月时将大鼠分３批处死，测尿液、肝脏、血清Ｓｅ和骨骼、肝脏、肾脏、血清Ｆ含量。结果两组氟中毒大鼠与对照组比较摄Ｆ量升高，排Ｆ／摄Ｆ比值降低。尿Ｆ的升高与水Ｆ浓度及饮Ｆ时间呈正相关。骨、肝Ｆ大量蓄积出现于氟中毒中期，血Ｆ在氟中毒晚期明显上升。同未加Ｓｅ氟中毒大鼠比较，两组加Ｓｅ组大鼠尿、肝、血Ｓｅ升高。与此同时大鼠摄食、饮水状况改善，体重增加；排尿量升高；尿Ｆ排泄量和排Ｆ／摄Ｆ比显著提高；同时骨、肝、肾和血清Ｆ含量降低。     

Carbon Disulphide Poisoning with Increased Ethereal Sulphate Excretion

A clear-cut change in urinary sulphate excretion has been found in a case of subacute carbon disulphide poisoning, the ethereal fraction being greatly increased to 1·59 g./l., that is, 70% of the total urinary sulphate. Three weeks later the figure was still significantly abnormal: 1·25 g./l., i.e., 59·6% of total sulphate excretion. The normal pattern of sulphate excretion was reached about six weeks after the last exposure: ethereal sulphate 0·20 g./l. (8·7%); inorganic sulphate 1·97 g./l. (85·7%); neutral sulphur 0·13 g./l.     

低剂量辐射对大鼠营养代谢的影响

雄性Ｗｉｓｔａｒ大鼠３０只，随机分为两组：实验组￣（１８７）Ｃｓ２３．５ｍＧｙ照射，每周一次，实验期３个月，总照射剂量２８０ｍＧｙ；对照组正常饲养。观察低剂量辐射对大鼠营养代谢的影响，结果表明：与对照组相比血清维生素Ａ、Ｅ水平无明显变化；血清总蛋白含量有所下降，氨基酸升高；血清常量元素升高，微量元素下降，但均无统计学显著性；尿维生素Ｂ＿１、Ｂ＿２排出量明显高于对照组水平，血清铁明显下降，具有统计学意义。     

Effects of habitual chitosan intake on bone mass,bone-related metabolic markers and duodenum CaBP D9K mRNA in ovariectomized SHRSP rats

We have demonstrated that the habitual intake of chitosan can decrease bone mass in ovariectomized (OVX) SHRSP rats fed a low-Ca diet (0.1%). In the present study, we examined both the etiology of bone loss induced by dietary chitosan and the preventive effect of vitamin C supplementation. Rats were OVX and maintained on one of the following diets for 6 wk: 10% cellulose (CE). 10% chitosan (CH) or 10% chitosan with sodium ascorbate (CHVC). CH caused a significant reduction in bone mineral density (BMD) and stiffness in femurs and the fourth lumbar vertebrae (L4). There was no significant difference in intestinal Ca absorption between CH and CE, whereas CH intake significantly reduced intestinal P absorption. The bone loss in CH rats was accompanied with an increase in urinary Ca excretion and a decrease in serum Ca as well as a significant increment In serum PTH and 1,25(OH)2D3. The vitamin D receptor and calcium binding protein D9K mRNAs were also significantly increased in the duodenum of CH rats. Vitamin C supplementation to CH caused an increase in the Ca and P contents of femurs as well as BMD of the L4, with a decrease in urinary Ca excretion. These results indicate that dietary chitosan with low Ca intake possibly induces the loss of bone mass by enhancing urinary Ca excretion rather than by inhibiting Ca absorption, and that vitamin C supplementation could prevent bone loss caused by chitosan through the increment of retained Ca followed by suppression of urinary Ca excretion.     

富硒酵母对铜负荷导致小鼠肝损伤的保护作用

目的探讨富硒酵母对小鼠铜负荷致肝损伤的保护作用。方法采用过量(512mg/kgbw·d)硫酸铜灌胃致小鼠肝损伤后,给予低、中、高(20、40、60mg/kgbw·d)的富硒酵母4w,观察补硒对肝脏丙二醛(MDA)含量、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性以及血清和肝组织中铜含量的影响,并进行肝脏病理组织学检查和肝细胞凋亡检测,同时测定血清中谷丙转氨酶(ALT)和谷草转氨酶(AST)活性。结果过量硫酸铜能导致小鼠肝脏损伤,与低、高剂量富硒酵母添加组相比,补充中剂量富硒酵母能显著缓解这种损伤,表现为血清和肝组织的铜含量显著降低,肝组织中SOD、GSH-Px活性增强,MDA含量减少,肝细胞凋亡显著减少。结论适量的富硒酵母能降低铜负荷导致的小鼠肝功能损伤,其机制可能与减轻铜离子介导的脂质过氧化有关。     

Quantitative aspects of the transformations of sulphur in sheep

1. [35S]sulphate was used to obtain quantitative estimates of the transfer of sulphur between the blood, rumen and postruminal tract of four sheep given brome grass (Bromus inermis) pellets or lucerne (Medicago sativa) pellets at the rate of 33 or 66 g/h. Sodium sulphate (0-4 g S/d) was infused into the rumen or abomasum of sheep given brome grass during four periods of 19 d and was not infused into the sheep during a subsequent period in which lucerne was given. The flow of sulphide, sulphate, microbial S and non-microbial organic S from the abomasum was estimated using 103Ru and 51Cr. 2. The concentration of inorganic sulphate in serum was increased to maximum values of 35-46 mg S/l by infusion of sulphate into the rumen or abomasum. The rate of irreversible loss of serum sulphate and rumen sulphide was positively related to the amount of sulphate infused. 3. Reabsorption of sulphate by the kidney reached a maximum of 0.69-1.1 mmol sulphate/l glomerular filtrate. 4. The transfer of sulphate from blood to the rumen was related to the concentration of inorganic sulphate in serum, attaining maximum values of 133 (+/- 13) mg S/d for sheep given brome grass plus sulphate, and 127-159 mg S/d for sheep given lucerne. 5. Bacteria derived 0.52-0.67 of organic S from rumen sulphide in sheep given brome grass, and approximately 0.45 of bacterial organic S was derived from sulphide for sheep given lucerne. Protozoa derived approximately 0.90 of organic S from bacteria. 6. It was estimated that endogenous organic S contributed 300-340 mg S/d to the rumen, and that 0.24-0.45 of S digested in the rumen was derived from endogenous sources.     

Hypocholesterolemic effect of indigestible fraction of Chlorella regularis in cholesterol-fed rats

The effects of Chlorella regularis powder (CP) and Chlorella regularis indigestible fraction (CIF) on serum and liver lipid concentrations and on fecal steroid excretion were estimated in rats fed diets containing 5 g/kg cholesterol and 2.5 g/kg sodium cholate. The ingestion of 12.7% CP or 5.3% CIF did not influence food intake or growth. CP and CIF decreased the levels of serum cholesterol, but had no effect on the levels of serum triacylglycerol and phospholipid. Liver cholesterol contents were lower in the CP and CIF groups than in the control group, but CP and CIF did not affect liver triacylglycerol content. CP and CIF increased the total amount of fecal neutral steroids excreted, but did not modify the total bile acid excretion. However, the soluble bile acid concentrations of reconstituted fecal water in the rats fed CP and CIF diets were lower than the control value. Moreover, CP and CIF had a high bile acid binding capacity in vitro. These results indicated that CIF had a hypocholesterolemic effect and enhanced fecal neutral steroid excretion while decreasing the soluble fecal bile acid concentration.     

硒对氟在大鼠体内蓄积,排泄的影响

通过饮水加氟（Ｆ５０ｍｇ／Ｌ）或／和加硒（Ｓｅ０．５ｍｇ／Ｌ）的方法，研究了硒对氟在大鼠体内蓄积、排泄的影响。结果表明饮水加氟可使大鼠血清氟、骨氟含量及尿氟排泄量显著增加；饮水同时加硒可显著降低氟中毒大鼠血清氟含量，但对大鼠骨氟含量、尿氟排泄量无显著影响。     

Effects of addition of arginine, cystine, and glycine to the bovine milk-simulated amino acid mixture on the level of plasma and liver cholesterol in rats

The effects of the addition of varying levels of arginine (Arg), cystine (Cys), and glycine (Gly) to the bovine milk-simulated amino acid mixture on the levels of plasma and liver cholesterol were investigated in rats. The diets containing a high amount of Cys lowered significantly the level of plasma cholesterol as the amount of Cys in diets increased. The serum high density lipoprotein (HDL)-cholesterol level and fecal excretion of acidic steroids were higher in rats fed the Cys diets than in those fed the Arg and Gly diets. No differences, however, was observed in the content of liver cholesterol. Liver triglyceride contents elevated significantly on feeding the Arg and Cys diets. Furthermore, liver phospholipid contents elevated significantly on feeding the Arg diet but lowered on feeding the Cys diet. Therefore, these results indicated that the feeding of a high amount of Cys lowers the plasma cholesterol levels as the result of the enhanced conversion of cholesterol to bile acids.     

Effects of exposure to cadmium on calcium metabolism: a population study.

The objective was to investigate the hypothesis that environmental exposure to cadmium may affect calcium metabolism in the population at large. The 1987 participants (965 men and 1022 women), from 20 to 80 years old, constituted a random sample of the population of four Belgian districts. The urinary excretion of cadmium, a measure of lifetime exposure, averaged 9.3 nmol/24 h in men (range 0.4-324 nmol/24 h) and 7.1 nmol/24 h (range 0.1-71 nmol/24 h) in women. Serum alkaline phosphatase activity and the urinary excretion of calcium correlated significantly and positively with urinary cadmium excretion in both men and women, and serum total calcium concentration negatively with urinary cadmium excretion in men only. The regression coefficients obtained after adjustment for significant covariates indicated that when urinary cadmium excretion increased twofold, serum alkaline phosphatase activity and urinary calcium excretion rose by 3-4% and 0.25 mmol/24 h respectively, whereas in men serum total calcium concentration fell by 6 mumol/l. After adjustment for significant covariates the relation between serum total calcium concentration and urinary cadmium excretion was not significant in women. The findings suggest that even at environmental exposure levels calcium metabolism is gradually affected, as cadmium accumulates in the body. The morbidity associated with this phenomenon in industrialised countries remains presently unknown and requires further investigation.     

The effect of molybdenum on the conversion of sulphate to sulphide and microbial-protein-sulphur in the rumen of sheep.

1. [35S]sulphate was used to measure the apparent turnover of sulphate, sulphide and microbial-protein-S in the rumen contents of four sheep that were intraruminally infused with 10 g sodium sulphate/d alone, or together with 126 mg sodium molybdate (50 mg molybdenum). 2. Infusion of molybdate increased the concentration of sulphate in rumen fluid from 2.2 to 7.2 mug S/ml and decreased the rate of reduction of sulphate to sulphide by 50%. Although the rate of sulphide production was slower, the concentration of sulphide in the rumen is suggested to explain these changes. 3. In animals that were not infused with molybdate, only one-third of the S (3.0 g/d) that passed through the sulphate pool in rumen fluid was converted to sulphide, decreasing to one-sixth when molybdate was infused. 4. The turnover of S amino acids in microbial protein was not significantly affected by molybdate. Only 52-57% of the S amino acid content of microbial protein was synthesized de novo by way of the sulphide pool.     

Effects of exposure to cadmium on calcium metabolism: a population study

The objective was to investigate the hypothesis that environmental exposure to cadmium may affect calcium metabolism in the population at large. The 1987 participants (965 men and 1022 women), from 20 to 80 years old, constituted a random sample of the population of four Belgian districts. The urinary excretion of cadmium, a measure of lifetime exposure, averaged 9.3 nmol/24 h in men (range 0.4-324 nmol/24 h) and 7.1 nmol/24 h (range 0.1-71 nmol/24 h) in women. Serum alkaline phosphatase activity and the urinary excretion of calcium correlated significantly and positively with urinary cadmium excretion in both men and women, and serum total calcium concentration negatively with urinary cadmium excretion in men only. The regression coefficients obtained after adjustment for significant covariates indicated that when urinary cadmium excretion increased twofold, serum alkaline phosphatase activity and urinary calcium excretion rose by 3-4% and 0.25 mmol/24 h respectively, whereas in men serum total calcium concentration fell by 6 mumol/l. After adjustment for significant covariates the relation between serum total calcium concentration and urinary cadmium excretion was not significant in women. The findings suggest that even at environmental exposure levels calcium metabolism is gradually affected, as cadmium accumulates in the body. The morbidity associated with this phenomenon in industrialised countries remains presently unknown and requires further investigation.     

大豆蛋白对人体血浆胆固醇的影响及机制探讨

目的观察大豆蛋白对正常人体血浆胆固醇浓度的影响并探讨其作用机制。方法选择健康大学生30名，男女各半，按血浆总胆固醇浓度、体重和性别均衡的原则，分为3组，在统一食谱、集中就餐的基础上，每天分别另外摄入30g酪蛋白，30g大豆分离蛋白，30g酪蛋白加880mg钙，共14d。实验开始和结束时．测量身高和体重：采血，测定血浆总胆固醇浓度。实验结束前，收集3d粪便，测定粪脂肪、钙、磷、镁和胆汁酸的排出量。结果(1)同实验开始时比，酪蛋白组血浆胆固醇浓度显著升高，而大豆蛋白组和酪蛋白加钙组血浆胆固醇浓度升高不明显。(2)同酪蛋白组比，大豆蛋白组粪钙、磷和镁的排出量均显著增加；粪脂肪和胆汁酸排出量分别增加33．6％和45．3％。(3)粪胆汁酸排出量与粪钙、磷、镁和脂肪的排出量呈显著性正相关。血浆胆固醇浓度随粪胆汁酸排出量增加呈下降的趋势。结论大豆蛋白降低血浆胆固醇浓度的机制可能是由于增加粪胆汁酸的排出量而导致肝脏中由胆固醇合成胆汁酸的增加，从而使血浆胆固醇浓度下降。     

Brewer's spent grain, serum lipids and fecal sterol excretion in human subjects with ileostomies

A crossover design studying lipid and apoprotein levels in serum and excretion of sterol, nitrogen and fat in ileostomy effluent was performed in 10 subjects fed diets with or without supplementation with brewer's spent grain, which is the residue of barley after the brewing of beer. More cholesterol, nitrogen, fat and energy were excreted in the ileostomy effluents when the subjects consumed a brewer's spent grain supplemented, high fiber diet than when they consumed a low fiber diet. No significant change was found in the daily net sterol excretion. The six subjects with low daily excretion of bile acids (less than 1000 mg/24 h) had increased cholesterol and net cholesterol and decreased bile acid excretion per day, and lowered serum LDL-cholesterol and apoprotein B levels after supplementation with brewer's spent grain. We propose that subjects with low daily bile acid excretion are suitable models for studying the effect of dietary changes on sterol excretion and serum lipid levels. Increased fecal cholesterol excretion is suggested to be the primary mechanism for the serum LDL-cholesterol lowering effect of brewer's spent grain.     

Effects of excess dietary tyrosine on cholesterol, bile acid metabolism and mixed-function oxidase system in rats

Excess dietary tyrosine (12%) caused hypercholesterolemia in male Wistar rats and significantly increased cytochrome P-450 and b5 contents. Bile flow and biliary output of total bile acids were significantly increased in rats fed this diet. Biliary output of cholesterol was not significantly altered, whereas that of taurocholic acid was significantly increased. Excess dietary tyrosine significantly decreased the fecal excretion of neutral steroids, whereas total steroid excretion was not significantly changed. The present results indicate that excess dietary tyrosine causes hypercholesterolemia without modifying the fecal total steroid excretion, thus supporting our previous hypothesis that stimulated synthesis of cholesterol is a main reason why excess dietary tyrosine leads to hypercholesterolemia.     

Zinc supplementation alters thyroid hormone metabolism in disabled patients with zinc deficiency.

We examined zinc (Zn) status in relation to thyroid function in disabled persons, because the association between Zn deficiency and thyroid function remains controversial.

After measuring serum free 3,5,3′-triiodothyronine (T3) and free thyroxine (T4) in 134 persons, TSH-releasing hormone (TRH) injection test and estimation of Zn status were conducted in persons with low free T3.

Thirteen had low levels of serum free T3 and normal T4. Patients with elevated levels of serum 3,3′,5′-triiodothyronine (rT3) showed an enhanced reaction of serum thyrotropin (TSH) after TRH injection. Nine of 13 patients had mild to moderate Zn deficiency evaluated by body Zn clearance and increased urinary Zn excretion. After oral supplementation of Zn sulphate (4-10 mg/kg body weight) for 12 months, levels of serum free T3 and T3 normalized, serum rT3 decreased, and the TRH-induced TSH reaction normalized. Serum selenium concentration (Type 1 T4 deionidase contains selenium in the rat) was unchanged by Zn supplementation.

Zn may play a role in thyroid hormone metabolism in low T3 patients and may in part contribute to conversion of T4 to T3 in humans.     

Dietary galacto-oligosaccharides mixture can suppress serum phenol and p-cresol levels in rats fed tyrosine diet

Phenols (phenol and p-cresol) are amino acid metabolites produced by intestinal bacteria. Some reports have demonstrated that the accumulation of phenols in the serum has toxic effects in renal failure patients. In this study, we found that phenols accumulated in the serum of rats given a tyrosine diet, and that dietary intake of a galacto-oligosaccharide mixture (GOS) suppressed the accumulation of phenols in serum. Rats were fed a basal diet, tyrosine diet (basal diet with 2.5% tyrosine) or GOS diet (tyrosine diet with 5% GOS) for 2 wk. The concentrations of phenols in the feces, cecal contents, serum and urine were determined. Concentrations of phenols in the serum, cecal contents and feces from rats fed the tyrosine diet were significantly higher than those in rats fed the basal diet. The concentrations of phenols in feces, cecal contents and serum, and urinary excretion in the GOS diet group were significantly lower than those in the tyrosine diet group. The pH of cecal contents was decreased by GOS intake. Furthermore, the serum concentrations of phenols were closely correlated with cecal concentrations. This finding suggested that concentrations of phenols in the serum reflected phenol production in the cecum contents. These results showed that dietary intake of GOS could modify the intestinal environment, and suppress the production of phenols in the intestinal tract and the accumulation of phenols in the serum. Thus, GOS may help improve the quality of life (QOL) of patients with renal failure.     

Tartary buckwheat sprout powder lowers plasma cholesterol level in rats

We examined the effects of different types of buckwheat sprouts on the plasma cholesterol concentration, fecal steroid excretion and hepatic mRNA expression related to cholesterol metabolism in rats. Rats were fed a cholesterol-free diet with 5 g of Kitawasesoba common buckwheat sprout powder (KS)/100 g, 5 g of Hokkai T no. 8 tartary buckwheat sprout powder (HS-8)/100 g or 5 g of Hokkai T no. 9 tartary buckwheat sprout powder (HS-9)/100 g of diet for 4 wk. Control rats were fed a diet with alpha-cornstarch instead of sprout powder for 4 wk. There were no significant differences in food intake, body weight, liver weight or cecal contents among the groups. Plasma total cholesterol concentrations in the HS-8 and HS-9 groups were significantly lower than in the control group, whereas there was no significant difference between the KS and control groups. Fecal bile acid excretion and cecal short-chain fatty acid concentrations in the KS, HS-8 and HS-9 groups were significantly greater than in the control group. Furthermore, fecal matter excretion in the KS, HS-8 and HS-9 groups tended to be increased compared to the control group, with that in the HS-8 group being significantly higher than in the control group. Hepatic cholesterol 7alpha-hydroxylase mRNA expression in the KS, HS-8 and HS-9 groups and hepatic HMG-CoA reductase mRNA expression in the HS-9 group were significantly higher than in the control group. The results suggest that tartary buckwheat sprout powder has a serum cholesterol-lowering function by enhancing fecal bile acid excretion through increased fecal matter excretion or the upregulation of hepatic cholesterol 7alpha-hydroxylase mRNA expression in rats.     

Curdlan and gellan gum, bacterial gel-forming polysaccharides, exhibit different effects on lipid metabolism, cecal fermentation and fecal bile acid excretion in rats.

The effects of curdlan (CD) and gellan gum (GG), bacteria-producing polysaccharides, on lipid concentrations of serum and liver, fecal bile acid composition and intestinal fermentation products were studied in rats fed diets containing cellulose powder (CP), CD or GG at 5% for 4 wk. The cecal weight of the CD group increased significantly as compared to that of the other two groups and the pH of its contents was significantly low. The gastrointestinal transit time in the GG group was significantly shorter than that in the CP and CD groups. No significant inter-group differences were observed in the serum concentrations of total cholesterol and HDL-cholesterol, but a significant decrease was observed in the hepatic total cholesterol concentration of the CD group as compared to that of the CP and GG groups. No significant difference in the total bile acid excretion in feces was observed among the groups, but significantly low values were observed in the proportion of secondary bile acids in the CD group as compared to those of the CP and GG groups. Amounts of short-chain fatty acids (acetic, propionic and butyric acid) and lactic acid in the cecal contents were significantly higher in the CD group than in the other two groups. These results reveal that dietary CD is easily degraded and fermented by intestinal bacteria in the cecum and lowers cholesterol concentration in the liver, while dietary GG shortens the gastrointestinal transit time, suggesting the promotion of evacuation.     

Hepatic PKA inhibition accelerates the lipid accumulation in liver

Zinc deficiency can change the concentrations of minerals and trace elements in the body. However, previous studies still had many limitations. To reveal the effects of zinc deficiency on homeostasis of 16 minerals and trace elements. Forty-five rats were divided randomly into three groups: normal zinc diet (30 mg/kg), low zinc diet (10 mg/kg), and pair-fed diet(30 mg/kg). The concentrations of 16 minerals and trace elements in serum, feces, urine, and liver were measured by inductively coupled plasma mass spectrometry. The excretion of 16 elements in urine and feces were calculated and compared. Zinc-deficient rats exhibited significant changes in up to 12 minerals and trace elements. The low zinc diet induced decreased excretion of zinc and concentrations of zinc in serum, feces, urine, and liver. Zinc deficiency increased feces concentrations of Mg, Cu, Se, K, Ag, Fe and Mn; decreased the concentrations of Mg, Cu, Se, K in liver and urine, and a diminished amount of Ag was observed in serum. Decreased urinary concentrations of Zn Ca, Mg, Cu, Se, K, Na, As and Cr, suggested that zinc-deficient rats increased the 9 elements’ renal reabsorption. Decreased concentrations of Ca in liver, urine, and feces, decreased excretion in urine and feces and increased serum total Ca suggested that zinc deficiency increased the redistribution of Ca in serum or other tissues. Zinc deficiency increased excretion of Cu, Se, Fe; and decreased the excretion of other 8 elements except for Ag. Zinc deficiency changed the excretion, reabsorption and redistribution of 12 minerals and trace elements in rats. Our findings are the first to show that zinc deficiency alters the concentrations of Ag, Cr, and As.