实验动物皮肤病原真菌检测方法的改良

目的对实验动物皮肤病原真菌2种培养方法进行了比较。方法将采集到的3只皮肤真菌感染病兔样品经由沙氏平皿法和沙氏试管斜面培养法分别进行培养。结果在3只真菌感染病兔中应用试管斜面法我们只检测到1例皮肤病原真菌阳性,而采用沙氏平皿法3例阳性全部检出。结论结合临床检测经验,我们认为本研究的沙氏平皿法优于沙氏试管斜面法,在实验动物皮肤病原真菌常规检测中具有推广应用价值。     

链脲佐菌素诱导长爪沙鼠Ⅰ型糖尿病模型的实验研究

目的探讨链脲佐菌素(STZ)诱导长爪沙鼠Ⅰ型糖尿病模型的可能性,并观察模型动物早期肾脏损害情况。方法雄性长爪沙鼠96只,随机分为正常对照组(NC组)、模型组1(DM1组)、模型组2(DM2组),DM1及DM2组沙鼠分别一次性腹腔注射100 mg/kg、200 mg/kg STZ,NC组注射等量柠檬酸盐缓冲溶液。注射STZ后1、2、4、6周末,分别监测沙鼠一般情况,血糖、胰岛素等血清学指标和尿液指标,并处死沙鼠进行胰腺和肾脏组织的病理学检查。结果注射STZ 24 h后,DM2组及DM1组部分沙鼠逐渐出现典型的"三多一少"症状,随着病程的发展,DM2组沙鼠持续高血糖,DM1组沙鼠血糖值与NC组差异有显著性(P0.05),但有下降趋势;DM2组沙鼠胰岛素显著性降低(P0.05),其他血清学指标及尿液指标均显著性升高(P0.05),DM1组沙鼠各指标差异无显著性。DM2组沙鼠及DM1组少数沙鼠胰腺组织中可见胰岛β细胞减少、空泡样变性等变化,DM2组沙鼠肾脏组织中出现肾小球基质增多,毛细血管襻扩张等病变,DM1组沙鼠肾脏组织未见明显变化。结论 STZ 200 mg/kg可成功诱导长爪沙鼠Ⅰ型糖尿病模型,在病程早期沙鼠肾脏结构和功能已经发生改变。     

Cancer morbidity and mortality among the liquidators of the Chernobyl accident: estimation of radiation risks

The work focuses on the results of the analysis of the cancer incidence among the Chernobyl emergency workers residing in Russia during 1991-2001. The analysis is based on the data for the cohort of male emergency workers from 6 regions of Russia including 55718 persons with documented external radiation doses in the range of 0.001-0.3 Gy who worked within the 30-km zone in 1986-1987. The mean age at exposure for these persons was 34.8 years old and the mean external radiation dose 0.13 Gy. In this cohort 1370 cases of solid cancer were diagnosed. Three follow-up periods were considered: 1991-1995, 1996-2001 and 1991-2001. The second follow-up period was chosen to allow for a minimum latency period of 10 years. Risk assessments were performed for two control groups: the first control group ("external") represented incidence rates for corresponding ages in Russia in general and the second control group ("internal") consisted of emergency workers. The estimated standardized incidence ratio (SIR) is in good agreement with that of the control within 95% CI. The values of the excess relative risk per unit dose 1 Gy (ERR/Gy) for solid malignant neoplasms have been estimated to be 0.33 (95% CI: -0.39, 1.22) (internal control) for the follow-up period 1991-2001 and 0.19 (95% CI: -0.66, 1.27) for 1996-2001. The analysis of cancer morbidity was carried out for the cohort of 29003 emergency workers who took part in liquidation of the consequences of the Chernobyl accident from 26 April 1986 to 25 April 1987. It was shown that the excess relative risk of cancer deaths per unit dose 1 Sv (ERR/Sv) is equal to 1.52 (95% CI: 0.20, 2.85).     

Autophagy occurs upstream or parallel to the apoptosome during histolytic cell death

Histolysis refers to a widespread disintegration of tissues that is morphologically distinct from apoptosis and often associated with the stimulation of autophagy. Here, we establish that a component of the apoptosome, and pivotal regulator of apoptosis, is also required for histolytic cell death. Using in vivo and ex vivo assays, we demonstrate a global apoptogenic requirement for dark, the fly ortholog of Apaf1, and show that a required focus of dark(-) organismal lethality maps to the central nervous system. We further demonstrate that the Dark protein itself is a caspase substrate and find that alterations of this cleavage site produced the first hypermorphic point mutation within the Apaf1/Ced-4 gene family. In a model of ;autophagic cell death', dark was essential for histolysis but dispensable for characteristic features of the autophagic program, indicating that the induction of autophagy occurs upstream or parallel to histolytic cell death. These results demonstrate that stimulation of autophagy per se is not a ;killing event' and, at the same time, establish that common effector pathways, regulated by the apoptosome, can underlie morphologically distinct forms of programmed cell death.     

Plasma lipid profiling across species for the identification of optimal animal models of human dyslipidemia

In an attempt to understand the applicability of various animal models to dyslipidemia in humans and to identify improved preclinical models for target discovery and validation for dyslipidemia, we measured comprehensive plasma lipid profiles in 24 models. These included five mouse strains, six other nonprimate species, and four nonhuman primate (NHP) species, and both healthy animals and animals with metabolic disorders. Dyslipidemic humans were assessed by the same measures. Plasma lipoprotein profiles, eight major plasma lipid fractions, and FA compositions within these lipid fractions were compared both qualitatively and quantitatively across the species. Given the importance of statins in decreasing plasma low-density lipoprotein cholesterol for treatment of dyslipidemia in humans, the responses of these measures to simvastatin treatment were also assessed for each species and compared with dyslipidemic humans. NHPs, followed by dog, were the models that demonstrated closest overall match to dyslipidemic humans. For the subset of the dyslipidemic population with high plasma triglyceride levels, the data also pointed to hamster and db/db mouse as representative models for practical use in target validation. Most traditional models, including rabbit, Zucker diabetic fatty rat, and the majority of mouse models, did not demonstrate overall similarity to dyslipidemic humans in this study.     

Discovery of benzodihydroisofurans as novel, potent, bioavailable and brain-penetrant prolylcarboxypeptidase inhibitors

A series of benzodihydroisofurans were discovered as novel, potent, bioavailable and brain-penetrant prolylcarboxypeptidase (PrCP) inhibitors. The structure-activity relationship (SAR) is focused on improving PrCP activity and metabolic stability, and reducing plasma protein binding. In the established diet-induced obese (eDIO) mouse model, compound ent-3a displayed target engagement both in plasma and in brain. However, this compound failed to induce significant body weight loss in eDIO mice in a five-day study.     

Pioglitazone induces lipid accumulation in the rat heart despite concomitant reduction in plasma free fatty acid availability

Thiazolidinediones are insulin-sensitizing drugs which have been proved to be effective in the treatment of type 2 diabetes. However, the action of thiazolidinediones on myocardial metabolism is only poorly recognized. Therefore, the aim of our study was to investigate the effects of two-week pioglitazone treatment (3 mg/kg/d) on lipid and carbohydrate metabolism in the heart of rats fed on a standard chow or on a high-fat diet (HFD) for three weeks. High-fat feeding increased myocardial protein expression of all peroxisome proliferator-activated receptor (PPAR) isoforms. The greatest response was, however, noted in the case of PPARγ. Surprisingly, administration of pioglitazone induced accumulation of free fatty acids (FFA) and diacylglycerol in the heart in both groups, despite concomitant reduction in plasma FFA concentration. The content of triacylglycerol was increased only in the HFD group. Pioglitazone treatment also shifted myocardial substrate utilization towards greater contribution of glucose in both groups, as evidenced by decreased rate of palmitate oxidation and higher 2-deoxyglucose uptake and elevated glycogen content. This could induce a mismatch between the rate of myocardial fatty acid uptake and oxidation leading to increased intracellular availability of fatty acids for non-oxidative metabolic pathways like synthesis of acylglycerols. Our data suggests that thiazolidinediones improve cardiac insulin sensitivity by mechanisms other than reduction in intramyocardial lipid content.     

Nuclear binding of the estrogen receptor in whole uteri

In order to show whether the estrogen complex (ER) in the intact cell binds to some nuclear component or whether it is in free equilibrium between the cytoplasm and the nucleus, we incubated intact uteri under conditions which increased the ratio of nuclear to cytoplasmic ER. These conditions included (a) the use of sucrose at concentrations greater than 0.75 M, (b) ethanol at 7.5% to 10%, or (c) 1 mM mercuric chloride or phenylmercuric acetate. Whereas (b) and (c) increased the ratio by preferentially denaturing the cytoplasmic ER, (a) caused ER to move from the cytoplasm into the nucleus by an undetermined mechanism. Uteri with a high ratio of nuclear to cytoplasmic ER were then washed, incubated in fresh “normal” incubation media, fractionated and the location of ER determined. If ER binding does occur in the nucleus, the high ratio of nuclear ER to cytoplasmic ER should be maintained, whereas if ER is in an equilibrium in the cell, ER should redistribute and reestablish the “normal” ratio. In all cases studied; i.e., after pretreatment with sucrose at different concentrations, ethanol at different concentrations and either mercuric chloride or phenylmercuric acetate, the ratio of nuclear to cytoplasmic ER remained high, suggesting that ER binds to some nuclear component in intact cells.