人膜相关蛋白TEB4的结构及其E3连接酶活性

TEB4(MARCH Ⅳ)是酵母Doa10的同源体,作为E3连接酶参与内质网相关蛋白的降解。TEB4和酵母Doa10定位于内质网上,包含一个环指域和多个跨膜域。这个环指结构位于蛋白的N端,具有特殊的C4HC3结构。在泛素结合酶UBC7参与的底物第48位赖氨酸特异点的泛素化反应中,分离开的环指域在细胞液中催化泛素的连接。这些特性与E3酶有关,E3酶是参与内质网相关蛋白降解的重要酶。和一些E3连接酶一样,TEB4可能参与神经退行性病变的调节。     

Multi‐modal imaging for assessment of tissue‐engineered bone in a critical‐sized calvarial defect mouse model

Tissue‐engineered bone (TEB) analysis in vivo relies heavily on tissue histological and end‐point evaluations requiring the sacrifice of animals at specific time points. Due to differences in animal response to implanted tissues, the conventional analytical methods to evaluate TEB can introduce data inconsistencies. Additionally, the conventional methods increase the number of animals required to provide an acceptable statistical power for hypothesis testing. Alternatively, our non‐invasive optical imaging allows for the longitudinal analysis of regenerating tissue, where each animal acts as its own control, thus reducing overall animal numbers. In our 6 month feasibility study, TEB, consisting of a silk protein scaffold with or without differentiated mesenchymal stem cells, was implanted in a critical‐sized calvarial defect mouse model. Osteogenesis of the TEB was monitored through signal variation, using magnetic resonance imaging (MRI) and near‐infrared (NIR) optical imaging with IRDye® 800CW BoneTag^TM (800CW BT, a bone‐specific marker used to label osteogenically differentiated mesenchymal stem cells and mineralization). Histological endpoint measurements and computed tomography (CT) were used to confirm imaging findings. Anatomical MRI revealed decreased signal intensity, indicating mineralization, in the TEB compared to the control (i.e. silk scaffold only) at various growth stages. NIR optical imaging results demonstrated a signal intensity increase of the TEB compared to control. Interpretation of the imaging results were confirmed by histological analysis. Specifically, haematoxylin and eosin staining revealing de novo bone in TEB showed that 80% of the defect was covered by TEB, while only 40% was covered for the control. Taken together, these results demonstrate the potential of multi‐modal non‐invasive imaging to visualize and quantify TEB for the assessment of regenerative medicine strategies. Copyright © 2015 John Wiley & Sons, Ltd.     

柴胡总提物对大鼠酒精性肝损伤的保护作用

目的:观察柴胡总提物对大鼠酒精性肝损伤的保护作用.方法:SD大鼠随机分为3组:酒精组、柴胡组、正常对照组,采用白酒灌胃辅以高脂饲料的方法建立大鼠酒精性肝损伤模型,给予柴胡总提物保护.检测血清中谷丙转氨酶(ALT)、谷草转氨酶(AST)、甘油三酯(TG)及肝组织中谷胱甘肽过氧化物酶(GSH-px)、丙二醛(MDA)水平;HE染色观察肝脏的病理变化.结果:酒精性肝损伤大鼠血清ALT、AST活性和TG含量明显升高(P＜0.01),肝组织GSH-px活性显著下降、MDA含量显著升高(P＜0.01);柴胡总提物能明显提高模型组大鼠肝组织GSH-px活性、降低MDA含量,降低血清ALT、AST活性和TG含量(与模型组比较:P＜0.01).柴胡总提物还能明显改善由酒精引起的肝组织脂肪样变和小叶片状坏死,柴胡组大鼠肝小叶结构趋于正常.结论:柴胡总提物能抑制酒精诱导脂质过氧化反应对肝组织的损伤,对酒精性肝损伤有明显保护作用.     

Differential mammary gland development in FVB and C57Bl/6 mice: implications for breast cancer research

A growing body of research suggests a linkage between pubertal mammary gland development and environmental factors such as diet as modifiers of long term breast cancer risk. Much of this research is dependent upon mouse models, which may vary between studies. However, effects may be strain dependent and further modified by diet, which has not been previously examined. Therefore, the objective of the present study was to determine whether mammary gland development differs between FVB and C57Bl/6 strains on diets containing either n-6 or n-3 polyunsaturated fats. Developmental measures related to onset of puberty and mammary gland development differed between strains. Mice fed the n-3 polyunsaturated fatty acids (PUFA) diet were shown to have lower numbers of terminal end buds, a marker of mammary gland development. This study helps to further clarify differences in development and dietary response between FVB and C57Bl/6 mice in order to more appropriately relate mammary gland research to human populations.     

Folic acid supplementation provided in utero and during lactation reduces the number of terminal end buds of the developing mammary glands in the offspring

Folate may prevent or promote cancer development and progression depending on the timing of intervention. Intrauterine exposure to folic acid has drastically increased in North America due to mandatory fortification and supplemental use of folic acid, which may influence the risk of breast cancer in the offspring. We investigated the effect of maternal folic acid supplementation, equivalent to the likely average post-fortification folate intake of a North American woman taking multivitamins containing folic acid, on terminal end buds, which reliably predict mammary tumor risk at adulthood in rodents. Female rats were placed on a control or supplemental diet for 3 weeks prior to mating and throughout pregnancy and lactation. Female pups were placed on the control diet at weaning until 50 days of age. The pups from the folic acid supplemented dams had a significantly lower number of terminal end buds than the pups from the dams fed the control diet (p = 0.014). Our data suggest for the first time that folic acid supplementation provided in utero and during lactation may lower mammary tumor risk in the offspring.     

Abnormal peripubertal development of the rat mammary gland following exposure in utero and during lactation to a mixture of genistein and the food contaminant vinclozolin

The impact of early exposure to endocrine disruptor mixtures on mammary gland development is poorly known. Here, we identify the effects of a conception to weaning exposure of rats to the phytoestrogen genistein (G) and/or the antiandrogen vinclozolin (V) at 1 mg/kg-d, alone or in association. Using several approaches, we found that G- and GV-exposed rats displayed significantly greater epithelial branching and proliferation, wider terminal end buds than controls at PND35, as well as ductal hyperplasia and periductal fibrosis. Focal branching defects were present in V-exposed rats. An increased ER and AR expression was observed in G- and GV- as compared to V-exposed rats at PND35. Surprisingly, a significant number of GV- and to a lesser extent, V-exposed animals displayed abnormal hyperplasic alveolar structures at PND50. Thus, gestational and lactational exposure to low doses of genistein plus vinclozolin may seriously affect peripubertal development of the rat mammary gland.     

The Insulin-Like Growth Factors (IGFs) and IGF Binding Proteins in Postnatal Development of Murine Mammary Glands

The insulin-like growth factors are mitogens and survival factors for normal mammary epithelialcells in vitro. Data reviewed here demonstrate that mRNAs for IGF-I and IGF-II, the IGFtype I receptor and the IGFBPs are expressed locally in mammary tissue during pubertal andpregnancy-induced growth and differentiation of murine mammary glands. IGF-I, IGF-II andthe IGF-IR were expressed in terminal end buds (TEBs) in virgin glands during ductal growth.In addition, IGF-II and IGF-IR mRNAs were expressed in ductal and alveolar epithelium inglands throughout postnatal development. Consistent with these results, IGF-I promoted ductalgrowth and proliferation in mouse mammary glands in organ culture. In addition to endogenousexpression of the IGFs and IGF-IR, the IGFBPs showed a varied pattern of expression inmammary tissue during postnatal development. For example, IGFBP-3 and -5 mRNAs wereexpressed in TEBs and ducts while IGFBP-2 and -4 mRNAs were expressed in stromal cellsimmediately surrounding the epithelium. These results support a role for the IGFs and IGFBPsas local mediators of postnatal mammary gland growth and differentiation.     

Noninvasive Cardiac Output Measurement by Transthoracic Electrical Bioimpedence: Influence of Age and Gender

Background  Thoracic electrical bioimpedance (TEB) as a method of measuring cardiac output (CO) is being explored increasingly over the last two decades, as a non-invasive alternative to the pulmonary artery catheter. The objective of this study was to establish normative data for measurement of CO by TEB and define the effect of age and gender on CO. Method  Stroke volume (SV) of 397 normal individuals (203 men, 194 women) in the age range of 10–77 years was determined using Kubisek and Bernstein formulae by TEB method. Derived cardiac parameters including CO, cardiac index (CI), systemic vascular resistance and resistance index were calculated and analyzed. Results  We found significant difference in CO among age groups and between gender. CO between Kubicek formula and Bernstein formula correlated well, but their means differed significantly. Cardiac indices peak in the third and seventh decade and were comparable between genders. Conclusion  A comprehensive data set of normalized values expressed as 95% confidence interval and mean ± SD in different age groups and different gender was possible for cardiac parameters using TEB. Sathyaprabha TN, Pradhan C, Rashmi G, Thennarasu K, Raju TR. Noninvasive cardiac output measurement by transthoracic electrical bioimpedence: influence of age and gender.     

Mammary gland differentiation by early life exposure to enantiomers of the soy isoflavone metabolite equol

The role of soy in reducing breast cancer risk has been suggested to be associated with early exposure to isoflavones, which alter mammary gland morphology. The objective of the study was to determine the effect of dietary exposure to the enantiomers of a key soy isoflavone metabolite, equol, on mammary gland development and later chemoprotection using the DMBA-induced animal model of breast cancer. Animals were exposed to S-(−)equol or R-(+)equol (250 mg/kg diet) during the neonatal (0–21 days) or prepubertal (21–35 days) periods only. Histological evaluation of the mammary glands showed that both enantiomers fed neonatally via the dam led to significant precocial mammary gland differentiation. By day 50, early S-(−)equol or R-(+)equol exposure resulted in a decrease in immature terminal end structures and an increase in mature lobules, suggesting an early ‘imprinting’ effect. Despite these morphological changes to the mammary gland, neonatal and prepubertal exposure to equol had no long-term chemoprevention against mammary tumors induced by DMBA, although for R-(+)equol there was a trend to delaying tumor formation. In summary, early exposure to equol was not chemopreventive, but neither did it increase tumor formation in response to DMBA, suggesting exposure in early life does not influence breast cancer risk.