Comparison of muscarinic receptor- and beta-adrenoceptor-mediated vasorelaxation between euthyroid and acute hyperthyroid rats

Hyperthyroidism was induced by subcutaneous injections of L-thyroxine (T4) (0.5 mg/kg/day) for 3 days in order to investigate the effects of acute hyperthyroidism on the vasorelaxing responses to isoprenaline and acetylcholine in isolated rat aortae. In the aortae, there was no significant difference in isoprenaline-induced relaxation between hyperthyroid and control rats, however acetylcholine-induced relaxation was significantly greater in hyperthyroid rats than in control rats. N(G)-nitro-L-arginine (L-NOARG), an inhibitor of nitric oxide (NO) synthase, reduced isoprenaline- and acetylcholine-induced relaxations in both hyperthyroid and control rats and in the presence of L-NOARG no significant difference in the acetylcholine-induced relaxation was seen between the two groups of rats. Indomethacin, a cyclo-oxygenase inhibitor, had no significant influence on both isoprenaline- and acetylcholine-induced relaxations in both control and hyperthyroid rats. 17-Octadecynoic acid (17-ODYA), a cytochrome P-450 mono-oxygenase inhibitor, reduced the both isoprenaline- and acetylcholine-induced relaxation in both hyperthyroid and control rats, and acetylcholine-induced relaxation was still greater in hyperthyroid rats than in control rats. These results indicate that an acute hyperthyroidism significantly enhances muscarinic receptor- but not adrenoceptor-mediated relaxations of the aortae and L-NOARG abolished an enhancement by acute hyperthyroidism of muscarinic receptor-mediated relaxation, suggesting that the effects may be due to an alteration in muscarinic receptor-mediated NO systems of the aortae at early stage of hyperthyroidism.     

Plant sterols and stanols: effects on mixed micellar composition and LXR (target gene) activation

Plant stanols and sterols of the 4-desmethyl family (e.g., sitostanol and sitosterol) effectively decrease LDL cholesterol concentrations, whereas 4,4-dimethylsterols (alpha-amyrin and lupeol) do not. Serum carotenoid concentrations, however, are decreased by both plant sterol families. The exact mechanisms underlying these effects are not known, although effects on micellar composition have been suggested. With a liver X receptor (LXR) coactivator peptide recruitment assay, we showed that plant sterols and stanols from the 4-desmethylsterol family activated both LXRalpha and LXRbeta, whereas 4,4-dimethyl plant sterols did not. In fully differentiated Caco-2 cells, the functionality of this effect was shown by the increased expression of ABCA1, one of the known LXR target genes expressed by Caco-2 cells in measurable amounts. The LXR-activating potential of the various plant sterols/stanols correlated positively with ABCA1 mRNA expression. Reductions in serum hydrocarbon carotenoids could be explained by the effects of the 4-desmethyl family and 4,4-dimethylsterols on micellar carotenoid incorporation. Our findings indicate that the decreased intestinal absorption of cholesterol and carotenoids by plant sterols and stanols is caused by two distinct mechanisms.     

Sex differences in adrenocortical structure and function

Summary Adrenal glands of adult female rats are heavier than the glands of corresponding male rats. Postpubertal orchiectomy increases the adrenal weight, an effect restored by testosterone replacement. Under the same conditions ovariectomy of 8 weeks duration does not change the adrenal weight while estradiol replacement enhances the relative adrenal weight.Karyometric studies have shown that nuclei in the female zona fasciculata cells are larger (app. 18%) than those of the male. Similar but only slight differences (2%) were observed in the zona reticularis. Orchiectomy results in enlargement of cell nuclei within all zones of the adrenal cortex; testosterone replacement has the opposite effect. Ovariectomy of 8 weeks duration slightly enhances the volume of nuclei of the zona glomerulosa cells, has no effect on the nuclei of the zona fasciculata and reduces the volume of nuclei in the zona reticularis. Estradiol replacement reduces the volume of nuclei of the zona glomerulosa cells but increases nuclear volume in the zona fasciculata and in the zona reticularis.Thus testosterone has an inhibitory effect on the adrenal cortex of the rat while the physiologic effect of estradiol on the morphology of this gland, particularly on the zona fasciculata cells is rather dubious.The author wishes to thank Mrs. B. Westerska and Miss K. Siejak for excellent technical assistance.This research was supported in part by a grant from the Zoological Committee, 2nd Department, Polish Academy of Sciences.This paper is dedicated to the memory of late Kazimierz Mietkiewski, M.D., Ph.D. whose encouragements and suggestions were most stimulating for my work.     

失代偿期肝硬化患者感染的危险因素及临床特点分析

目的：分析失代偿期肝硬化患者感染的相关危险因素和临床特点。方法：回顾性分析我院2012年4月--2013年4月住院的197例肝硬化失代偿期患者,比较感染患者与非感染患者的年龄、性别、肝功能分级、白细胞水平、门静脉内径、肝硬化并发症、侵入性操作措施、应用抗菌药物、住院时间等差异。结果：197例患者中发生感染的56例,其中以呼吸道和腹部感染为主。统计发现肝功能分级、白细胞水平、侵入性操作、住院时间及抗菌药的运用等与感染因素有关（P〈0．05）。结论：引起失代偿期肝硬化感染的危险因素是多方面的,临床特点也较突出,需要我们采取防措施去避免。     

Investigation of liver binding of pentachlorophenol based upon measurement of protein adducts

Abstract

Covalent binding of reactive metabolites of pentachloropheno (PCP) was investigated both in vitro andin vivo in the livers of male Sprague-Dawley rats via measurement of protein adducts. Cysteinyl adducts of quinones andsemiquinones in liver cytosolic (Cp) andnuclear (Np) proteins were assayed after catalytic cleavage by Raney nickel. Results from in vitro experiments confirmed that PCP metabolism produced tetrachlorobenzoquinones andthe comsponding tetrachlorobentosemiquinones which subsequently bound to sulphydryl groups in liver proteins. In vivo, the production of cysteinyl adducts increased with the administered dosage (0–40 mg PCP per kg body weight) andpresented evidence of saturable metabolism. Results suggest two metabolic pathways for PCP, including a high-affinity low-capacity pathway anda low-affinity high-capacity pathway. Time-course experiments in vivo andin vitro suggested that quinone adducts partlcipated in multiple substitution reactions with protein and/or non-protein thiols, andpointed to possible formation of protein-protein cross-links in vivo. The elimination rate constants of quinone adducts in vitro were about 0.35 h^?1 in liver Cp. The elimination of quinone adducts in vivo appeared to follow biphasic kinetics with rate constants for the terminal phase being 0.014 and0.008 h^?1 in liver Cp andNp, respectively.     

Curcumin Prevents Bile Canalicular Alterations in the Liver of Hamsters Infected with Opisthorchis viverrini

Opisthorchis viverrini infection causes inflammation and liver injury leading to periductal fibrosis. Little is known about the pathological alterations in bile canaliculi in opisthorchiasis. This study aimed to investigate bile canalicular alterations in O. viverrini-infected hamsters and to examine the chemopreventive effects of curcumin on such changes. Hamsters were infected with O. viverrini and one group of animals was fed with 1% dietary curcumin supplement. Animals were examined during the acute infection phase, days 21 and 30 post-infection (PI) and chronic infection phase (day 90 PI). Scanning electron microscopy revealed that in the infected group fed with a normal diet, bile canaliculi became slightly tortuous by 30 day PI and more tortuous at day 90 PI. Transmission electron microscopy showed a reduction in microvilli density of canaliculi starting at day 30 PI, with a marked loss of microvilli at day 90 PI. These ultrastructral changes were slightly seen at day 21 PI, which was similar to that found in infected animals fed with 1% curcumin-supplemented diet. Notably, curcumin treatment prevented the reduction of microvilli density, reduced the dilation of bile canaliculi, and decreased the tortuosity of the bile canaliculi relative to non-infected animals on a normal diet at days 30 and 90 PI. These results suggest that curcumin reduces alteration of bile canaliculi and may be a promising agent to prevent the onset of bile duct abnormalities induced by O. viverrini infection.     

定量蛋白质组学研究揭示知母可缓解2型糖尿病模型大鼠肝脏代谢异常

2型糖尿病(type 2 diabetes mellitus, T2DM)是一种在全球范围内广泛存在的代谢性疾病,不及时治疗可能会引发众多危及生命的并发症。肝脏代谢在糖尿病发生发展的过程中扮演着至关重要的角色。目前已有报道中药知母用于缓解胰岛素抵抗及糖尿病,但其能否缓解糖尿病中肝脏代谢的异常仍有待深入研究。因此,提取了高脂饮食和化学药物链脲佐菌素(streptozotocin, STZ)诱导的2型糖尿病大鼠模型、知母提取物处理的2型糖尿病大鼠模型、高脂饮食大鼠模型以及正常饮食大鼠对照组的肝脏蛋白,通过基于质谱的定量蛋白质组学串联质量标签(tandem mass tag, TMT)标记技术获得定量蛋白质组数据。利用生物信息学软件对各组数据进行层次聚类分析及主成分分析,并以P<0.05,差异倍数(fold change)>1.5作为阈值标准进行火山图分析,发现知母提取物治疗组相较未治疗组与正常对照组更接近,表明肝脏组织定量蛋白质组数据能够反映知母提取物对2型糖尿病大鼠模型的治疗效果。筛选获得了表达水平与知母提取物治疗密切相关的关键蛋白簇。利用在线网站分析蛋白簇的GO功能与KEG...     

Different responses of circulating ghrelin, obestatin levels to fasting, re-feeding and different food compositions, and their local expressions in rats

Obestatin, a sibling of ghrelin derived from preproghrelin, opposes several physiological actions of ghrelin. Our previous study has demonstrated that both plasma ghrelin and obestatin levels were decreased significantly 2h after food intake in human. To further expand current knowledge, we investigated the temporal profiles of their levels in ad libitum fed rats, 48h fasted rats and 48h fasted rats refed 2h with a standard chow, crude fiber, 50% glucose or water, and their expressions in stomach, liver and pancreatic islets immunohistochemically. Plasma ghrelin and obestatin levels were measured by EIA. Plasma leptin, insulin and glucose levels were also evaluated. Both plasma ghrelin and obestatin levels increased significantly in fasted rats compared with ad libitum fed rats. The ingestion of standard chow produced a profound and sustained suppression of ghrelin levels, whereas plasma obestatin levels decreased significantly but recovered quickly. Intake of crude fiber or 50% glucose, however, produced a more profound and sustained suppression of obestatin levels, though they had relatively less impact on ghrelin levels. Plasma glucose was the only independent predictor of ghrelin levels, obestatin levels, and ghrelin to obestatin ratios. Obestatin immunoreactivity was detected in the fundus of stomach, liver and pancreatic islets, with roughly similar patterns of distribution to ghrelin. These data show quantitative and qualitative differences in circulating ghrelin and obestatin responses to the short-term feeding status and nutrient composition, and may support a role for obestatin in regulating metabolism and energy homeostasis.     

Agouti-related protein has an inhibitory paracrine role in the rat adrenal gland

alpha-Melanocyte-stimulating-hormone (alpha-MSH) is an agonist at the melanocortin 3 receptor (MC3-R) and melanocortin 4 receptor (MC4-R). alpha-MSH stimulates corticosterone release from rat adrenal glomerulosa cells in vitro. Agouti-related protein (AgRP) an endogenous antagonist at the MC3-R and MC4-R, is expressed in the adrenal gland. We investigated the expression of the MC3-R and MC4-R and the role of AgRP in the adrenal gland. MC3-R and MC4-R expression was detected in rat adrenal gland using RT-PCR. The effect of AgRP on alpha-MSH-induced corticosterone release was investigated using dispersed rat adrenal glomerulosa cells. AgRP administered alone did not affect corticosterone release, but co-administration of AgRP and alpha-MSH attenuated alpha-MSH-induced corticosterone release. To investigate glucocorticoid feedback, adrenal AgRP expression was compared in rats treated with dexamethasone to controls. AgRP mRNA was increased in rats treated with dexamethasone treatment compared to controls. Our findings demonstrate that adrenal AgRP mRNA is regulated by glucocorticoids. AgRP acting via the MC3-R or MC4-R may have an inhibitory paracrine role, blocking alpha-MSH-induced corticosterone secretion.     

Exhibition of persistent and drug-tolerant L-form habit of <Emphasis Type="Italic">Mycobacterium tuberculosis</Emphasis> during infection in rats

A model for studying mycobacterial L-form formation in vivo was established to demonstrate the ability of M. tuberculosis to behave as a drug-tolerant L-form persister. Rats were infected by intranasal (i.n.) and intraperitoneal (i.p.) routes with 1×108 cells/ml of M. tuberculosis. At weekly intervals during a period of five weeks, samples from lung, spleen, liver, kidney, mesenterial and inguinal lymph nodes, broncho-alveolar and peritoneal lavage liquid were plated simultaneously on Löwenstein-Jensen (LJ) medium or inoculated into specially supplemented for L-forms Dubos broth (drug-free and drug-containing variants). The use of liquid media enabled isolation of mycobacterial L-form cultures during the whole period of experiment including the last two weeks, when tubercle bacilli were not isolated on LJ medium. An unique feature of mycobacterial L-forms was their ability to grow faster than the classical tubercle bacilli. Isolation and growth of L-form cultures in primary drug-containing media demonstrated their drug-tolerant properties. Electron microscopy of liquid media isolates showed that they consisted of morphologically heterogenous populations of membrane-bound and of variable sized L-bodies that completely lack cell walls. The identity of the isolated non-acid fast and morphologically modified L-forms as M. tuberculosis was verified by specific spoligotyping test. The results contribute to special aspects concerning the importance of mycobacterial L-form phenomenon for persistence and latency in tuberculosis, phenotypic drug tolerance, as well as for diagnosis of difficult to identify morphologically changed tubercle bacilli which are often mistaken for contaminants.