碘过量与维生素A交互作用对垂体-甲状腺轴形态学变化的影响

目的观察碘过量与维生素A交互作用对垂体-甲状腺轴形态结构变化的影响。方法将昆明种小鼠分为5组：对照组（NI）;高碘组（HI）;低维生素A组（LVA）;高碘低维生素A组（HI＋LVA）;高碘补维生素A组（HI＋VA）。在实验3个月、6个月时,测定小鼠甲状腺绝对质量与相对质量,观察甲状腺组织形态变化及甲状腺和脑垂体超微结构的变化。结果3个月、6个月时HI组小鼠甲状腺绝对质量和相对质量显著高于对照组（P〈0．05）;HI＋VA组小鼠的绝对质量和相对质量6个月时显著低于HI＋LVA组（P〈0．05）,略轻于HI组。光镜下甲状腺肿发生比率3个月时,HI组、HI＋LVA组、HI＋VA组均高于NI组,差异有统计学意义（P〈0．05）;6个月时,除LVA组,其余各组均高于NI组,差异有统计学意义（P〈0．05）。光镜结果显示3个月时HI组已经出现高碘性甲状腺肿,电镜下呈现甲状腺滤泡上皮细胞损伤,HI＋VA组这种状况有所改善。结论维生素A对甲状腺形态有一定的保护作用;补充适量的维生素A能使高碘小鼠的甲状腺质量和甲肿率降低,但不足以恢复到适碘组水平,说明补充维生素A可以部分拮抗高碘造成的影响。     

Effect of vitamin B12 and folic acid deficiencies on neutrophil function.

Morphological and quantitative neutrophil abnormalities are common in the megaloblastic anemias of vitamin B12 and folic acid deficiency. Little is known, however, about the role of these vitamins in normal leukocyte function. Seven patients with megaloblastic bone marrows, four with vitamin B12 deficiency and three with folic acid deficiency, were studied to determine the effect, if any, of these deficiencies on leukocyte function. Phagocytosis of staphylococci, hexose monophosphate shunt activation with phagocytosis, and microbicidal capacity against Staphylococcus aureus were determined prior to the institution of specific therapy. In two instances, these studies were repeated following treatment. There was no impairment of phagocytosis per se, and resting metabolism was not significantly decreased. With phagocytosis, however, metabolic activation was decreased to 35%-36% of control values in the leukocytes of patients with vitamin B12 deficiency but not in the leukocytes of patients with folic acid deficiency. Bacterial killing was slightly decreased in vitamin B12 but not in folic acid deficiency. These abnormalities of function were reversed after specific therapy. These findings suggested a specific role for vitamin B12 in the production of intermediates necessary for normal cell function.     

补碘对缺碘大鼠甲状腺功能及形态的影响

目的研究不同剂量补碘对缺碘Wistar大鼠甲状腺的影响。方法于2003—03～2004—03取中国医科大学实验动物部4周龄Wistar大鼠经低碘饲料喂养3个月建立缺碘大鼠模型，对其进行8个月的1倍、3倍和6倍补碘，3个补碘量分别对应于前期流行病调查所见的3个农村社区的碘摄入水平。观察缺碘大鼠经不同剂量补碘后甲状腺功能、形态的变化。结果在补充1倍、3倍和6倍碘后，缺碘甲状腺质量分数未能恢复，仍然为甲状腺肿，甲状腺内碘潴留。电镜下缺碘引起的内质网扩张和线粒体肿大在补碘后未见恢复，且随补碘剂量的增加，超微结构损伤呈现加重的趋势。结论对缺碘动物单纯补碘可能难以纠正起初缺碘引起的甲状腺损伤，甲状腺可能处于亚临床病理状态。     

补碘对缺碘大鼠甲状腺功能及形态的影响

目的研究不同剂量补碘对缺碘Wistar大鼠甲状腺的影响。方法于2003-03～2004-03取中国医科大学实验动物部4周龄Wistar大鼠经低碘饲料喂养3个月建立缺碘大鼠模型,对其进行8个月的1倍、3倍和6倍补碘,3个补碘量分别对应于前期流行病调查所见的3个农村社区的碘摄入水平。观察缺碘大鼠经不同剂量补碘后甲状腺功能、形态的变化。结果在补充1倍、3倍和6倍碘后,缺碘甲状腺质量分数未能恢复,仍然为甲状腺肿,甲状腺内碘潴留。电镜下缺碘引起的内质网扩张和线粒体肿大在补碘后未见恢复,且随补碘剂量的增加,超微结构损伤呈现加重的趋势。结论对缺碘动物单纯补碘可能难以纠正起初缺碘引起的甲状腺损伤,甲状腺可能处于亚临床病理状态。     

轻、中度碘过量对碘缺乏大鼠甲状腺功能和形态的影响

目的探讨轻、中度碘过量对碘缺乏Wistar大鼠甲状腺功能和形态影响。方法碘缺乏大鼠以饮用1%过氯酸钾溶液制备,分成0μg/L、840μg/L和1680μg/L碘组。双蒸水(DDW)组饲以DDW和普通饲料。固相免疫放射法(IRMA)测定血清TSH,放射免疫法(RIA)测定血清TT3、TT4、rT3和甲状腺组织TT4。光镜、电镜下观察甲状腺形态学变化。图像分析系统测量大鼠滤泡上皮细胞高度和滤泡腔的面积。结果补碘90天时,碘过量组血清TSH明显低于低碘对照组(均P<0.05),但与DDW组相比差异无显著性。1680μg/L碘组血清TT3值明显低于低碘对照组和DDW(均P<0.05),碘过量组血清TT4值明显高于低碘对照组和DDW组(均P<0.001),血清rT3高于低碘对照组和DDW组,但是差异无显著性,碘过量组甲状腺组织TT4含量明显高于低碘对照组和DDW组(均P<0.001)。甲状腺的相对重量均明显高于DDW组和低碘对照组(P<0.001和P<0.05)。碘过量组随着时间延长,滤泡上皮变扁,滤泡周围毛细血管逐渐减少,巨滤泡形成,同时有部分滤泡增生。碘过量组非增生滤泡上皮细胞高度明显小于DDW组和低碘对照组(均P<0.001),1680μg/L碘组泡腔面积明显大于DDW组和低碘对照组(均P<0.001)。结论轻、中度过量碘(尿碘中位数,MUI为300和600μg/L)处理90天,使碘缺乏大鼠甲状腺功能亢进,低碘致甲状腺肿不能完全恢复,甲状腺滤泡异质性增加。     

低碘和高碘对大鼠甲状腺细胞凋亡的影响

目的 研究低碘和高碘对大鼠甲状腺细胞凋亡的影响。方法 利用病区的低碘粮食喂养大鼠，同时饮用不同质量浓度的加碘水，复制低碘和高碘动物模型，于20周后在光、电镜下观察甲状腺形态结构改变，原位末端标记方法对甲状腺细胞凋亡进行检测。结果 与对照组相比，低碘和高碘组甲状腺凋亡细胞数明显增多。结论 低碘和高碘均诱发大鼠甲状腺细胞凋亡，进而调节甲状腺的形态结构和功能。其中以低碘组作用明显，提示细胞凋亡过度是引起低碘和高碘性甲状腺功能低下的重要原因。     

Multivitamin prophylaxis in prevention of post-gastric bypass vitamin and mineral deficiencies.

One hundred forty patients were followed for a mean 24.2 months after gastric bypass. Postop multivitamin (MV) prophylaxis was recommended for all patients and 90 of 140 patients (64 percent) were regularly compliant. Deficiencies in iron, vitamin B-12 or folate were recognized in 88 of 140 patients (63 percent). Thirty of 45 patients (67 percent) with iron deficiency developed anemia. Forty-three of the 52 patients who did not have deficiencies were regularly taking MV vs 47 of 88 patients who developed deficiencies (P less than 0.001). MV prophylaxis was successful in preventing folate (P less than or equal to 0.05) and vitamin B-12 deficiencies (P less than or equal to 0.02) but did not prevent development of iron deficiency or subsequent anemia. There was no correlation between taking prescribed supplements and resolution of either iron deficiency of anemia. B-12 and folate supplements corrected deficiencies in 73 percent of cases. We conclude that oral MV prophylaxis is useful in preventing folate and B-12 deficiency after gastric bypass. Additional prophylactic iron supplements should be provided for women to prevent iron deficiency and associated anemia.     

Effect of iodine supplementation on a pediatric population with mild iodine deficiency.

A cross-sectional study in two stages consisted of healthy children to assess the effect of iodine supplementation on a pediatric population with mild iodine deficiency in an ongoing program in the Province of Pontevedra, northwestern Spain. In the first survey (1984), 1565 schoolchildren and in the second survey (1995) 907 schoolchildren were randomly selected from the population. In January 1985, a mandatory consumption of iodized salt in our region was begun. In both surveys we studied prevalence of goiter, urinary iodine excretion, and prevalence of thyroid dysfunction. Similar prevalences of goiter were observed in both surveys, 3.7% versus 3.9%; however, significantly lower prevalence of Ib and II degree goiters were observed in the second survey. The mean iodine excretion was 88.6 +/- 73 microg/L (median 66.3) and 146.4 +/- 99 microg/L (median 115.7), p < 0.01 for the first and second surveys, respectively. Finally, the overall prevalence of thyroid dysfunction was similar in both surveys, 9.2% versus 7.0%; however, significantly lower prevalence of suppressed serum thyrotropin (TSH), considered as a marker of subclinical hyperthyroidism, was observed in the second survey when compared to the first, 0.1% versus 2%, p < 0.01. Our results are in agreement with the recent data from Denmark, where the prevention of subclinical hyperthyroidism occurring in the elderly as a consequence of longstanding mild iodine deficiency is the reason that the Danish finally started iodine supplementation on a national basis. In conclusion, long-term correction of mild iodine deficiency in a pediatric population has beneficial effects on the prevalence of high-degree goiters, and this correction reduces significantly the prevalence of subclinical hyperthyroidism. The present observation constitutes a strong argument for correcting even mild iodine deficiency.     

Effect of the progesterone antagonist mifepristone on the hypothalamo-hypophysial-ovarian axis in rats

Treatment of female rats for 3 weeks with the antigestagen 11 beta-(4-dimethylaminophenyl)-17 beta-hydroxy-17 alpha-(prop-1-ynyl)-estra- 4,9-dien-3-one (mifepristone) results in pituitary and ovarian enlargement. The present study dealt with the possible mechanism(s) of these responses. Ovarian enlargement appeared to be dependent upon prolactin. In the absence of prolactin, during combined treatment with mifepristone and the dopamine agonist 2-Br-alpha-ergokryptine, ovarian growth was significantly suppressed. It was unclear why persistent hyperprolactinaemia, due to treatment with mifepristone, resulted in persistence of functionally active corpora lutea despite intermittent ovulation, while persistent hyperprolactinaemia due to ectopic pituitary grafts did not. Pituitary enlargement appeared to be dependent upon the persistence of ovarian oestrogen secretion during the treatment period. Ovariectomy or lactation fully inhibited this response. Pituitary enlargement and prolactin secretion in ovariectomized rats in response to exogenous oestrogen (injections of oestradiol benzoate) were significantly enhanced by additional treatment with mifepristone. It is concluded that mifepristone facilitates the effect of oestrogen on pituitary lactotrophs, thereby enhancing pituitary growth. Ovarian enlargement during treatment with mifepristone may be specific for rats due to the luteotrophic action of prolactin in these animals. Pituitary enlargement due to facilitation of oestrogen-induced pituitary growth may become a focus of attention when this or similar antigestagenic drugs are being used for prolonged periods in clinical trials, e.g. for limiting steroid-sensitive tumour growth.     

钙、维生素D缺乏大鼠长骨成骨细胞的维生素D受体水平

对正常、钙缺乏和维生素D缺乏的大鼠 ,观察其体外培养的长骨成骨细胞的维生素D受体最大结合容量 ,结果显示维生素D缺乏组显著低于正常组 (P <0 .0 1)。     

Effect of pinealectomy on the undernutrition-induced suppression of the reproductive axis in rats

Food restriction is known to sensitize the reproductive axis of rats to the inhibitory action of the pineal gland and its hormone, melatonin. The present study investigated the effect of pinealectomy on the undernutrition-related reproductive suppression. Three groups of animals (control, sham pinealectomy or pinealectomy) were subjected to either 3 weeks of 50% food restriction or ad libitum feeding under a lighting regimen of 14 h light and 10 h dark. At the end of the treatment period, body weight, testes weight, accessory organ weights, serum LH and serum testosterone were determined. In the pinealectomized animals, accessory organ weights and serum testosterone levels increased significantly. As compared to the controls, underfed pinealectomized animals had a partial recovery of the reduced accessory organ weights and normalization of the serum testosterone levels. These findings suggests that pinealectomy has a protective effect on the gonads of both control and underfed animals and that underfed animals are more sensitive to this protective mechanism.     

Effect of vitamin E on experimental inflammation in rats

Besides other mediators like prostaglandins, kinins and histamine, oxygen radicals potentiate inflammations. Vitamin E as natural antioxidant could scavenge radicals produced during an inflammation and therefore reduce the inflammatory response. In experiments with male Wistar rats maintained on a diet deficient in or supplemented with vitamin E for 6 weeks the influence of the administration of DL-alpha-tocopherol on the inflammation of the right hind paw was tested. The irritation produced by injection of Freund's complete adjuvants was observed for 21 days. Measuring the thickness of the paw and the activity of acid phosphatase in the paw tissue there was no difference in the intensity of inflammation among the control and the vitamin-E-deficient diet groups. The supplementation with a pharmacological dose of tocopherol (324 mg DL-alpha-tocopherol/100 g food) had no effect on the inflammation of animals with different vitamin E supplements. Differences in the antioxidant status (contents of tocopherol and malondialdehyde in several organs, activity of creatine kinase in plasma) among the groups were mainly linked to the various tocopherol supplies. The irritation increased the lipid peroxidation in liver mitochondria and the activity of creatine kinase in the plasma. The data show no influence of vitamin E on this kind of inflammation.     

碘过量摄入对雄性大鼠骨代谢的影响

目的观察碘过量摄入对雄性大鼠骨组织的毒性及损伤性作用。方法复制不同剂量的碘过量摄入雄性大鼠动物模型，并设适碘组为对照，分别喂养3、6、12个月，观察实验大鼠离体股骨和腰椎L1-4的骨密度（BMD）及骨组织形态计量学指标变化。结果摄入碘过量3个月时，雄性大鼠股骨下端骨量及骨结构参数与对照组比较差异均无统计学意义；碘过量摄入6个月时，各剂量实验组的大鼠腰椎BMD均显著升高（均P〈0．05），骨形态计量学参数表明骨代谢处于旺盛阶段；在碘过量摄入12个月时，各碘过量组均未出现骨量异常改变，但骨结构参数——骨小梁盲端数有显著升高（均P〈0．05），提示碘过量导致骨小梁出现断裂，正常的骨组织结构被破坏。结论短期碘过量摄入对雄性大鼠的骨代谢及骨组织结构不会造成严重影响，长期碘过量摄入往往会导致骨结构的破坏，雄性大鼠对碘过量的耐受性是有一定限度的。     

Effect of dietary restriction on hepatic vitamin A content in aging rats.

The size and number of fat-storing cells (FSC), considered to be the main liver storage site of vitamin A, as well as hepatic vitamin A content, were studied in aging female Sprague-Dawley rats subjected soon after weaning to dietary restriction (R), that is, 60% of food consumed by their ad libitum-fed controls (A). In A or R rats, the FSC index (number of cells per 1000 hepatocytes) and volume density (% of hepatic volume) were increased significantly at 24-27 months compared with the younger age groups. The lipocyte index and volume density were also found to be significantly higher, after the first year, in R rats when compared to corresponding age-matched A controls. An increase in total vitamin A content was also noted with age in both groups. R rats exhibited higher retinol, retinyl ester, and total retinoid content than their corresponding controls, but the differences were statistically significant only at 12-14 and 24-27 months. These results indicate that, during aging, dietary restriction markedly increases vitamin A content in liver tissue, a change that may be relevant to the beneficial effect of this dietary manipulation on liver function.     

慢性多重应激大鼠ECG变化和下丘脑-垂体-肾上腺轴应激反应增高

目的研究慢性多重应激大鼠脱离应激源后心电图（Electrocardiogram,ECG）变化和下丘脑-垂体-肾上腺（hypothalamic-pituitary-adrenocortical,HPA）轴应激反应。方法健康雄性SD大鼠20只随机分为应激组和对照组。选用刺激脉冲随机变动的噪声、足底电击、强迫游泳、束缚和夜间光照的复合刺激为应激组大鼠应激源,应激刺激持续30d,建立大鼠慢性多重应激模型。于应激刺激前和完全脱离应激源后3d记录心电图,分析血清促肾上腺皮质激素（ACTH）和皮质酮（corticosterone,Cor）的变化。结果刺激4周后,脱离应激源3d,在1h心电图记录期中,大鼠心律失常类型和次数明显多于应激前和对照组:持续窦性心动过速或窦性不齐、房性期前收缩（应激前1.4±0.7vs应激后40.2±5,P<0.01）、室性期前收缩（应激前3.1±0.6vs应激后55.7±4,P<0.01）、阵发性室速（应激前0vs应激后23.8±6,P<0.01）。心率明显增快[（371.3±12）次/min→（508.7±10）次/min,P<0.01]、RR间期明显缩短[（171.6±5）ms→（111.5±0.5）ms,P<0.01]、ST段抬高或下移、T波高耸直立或低平,血清ACTH[（53.1±4）ng/L→（234.7±16）ng/L,P<0.01]和Cor[（16±4）μg/L→（279±50）μg/L,P<0.01]水平明显增高。结论慢性多重应激大鼠在脱离应激源后仍存在心律失常,并且HPA轴应激反应增高。