睾酮对胰岛素诱导的肝细胞糖原合成和Akt/GSK3β磷酸化水平的影响

目的:探讨睾酮(T)在肝脏胰岛素抵抗(IR)形成过程中的作用及其分子途径。方法:将成年C57BL/6雌鼠随机分为T组(n=11)及对照组(n=10),T组小鼠每日腹腔注射T(10μg/g体质量,溶剂为蓖麻油),对照组每日腹腔注射相同体积的蓖麻油,连续给药24周后处死,分离出原代小鼠肝细胞进行体外培养,用胰岛素(Ins)处理细胞后,通过液闪法检测原代肝细胞中的糖原合成率。分别用10~(-5) mol/L和10~(-7) mol/L浓度的T溶液短时间(1 h)或长时间(36 h)处理体外培养的人肝癌细胞系BEL-7404后,再用Ins处理BEL-7404细胞,然后通过液闪法检测细胞中的糖原合成率;并通过免疫印迹法检测细胞中Akt、GSK3β蛋白的表达水平和磷酸化水平。结果:Ins对T组小鼠原代肝细胞中糖原合成的诱导作用显著低于对照组(P0.05),提示T组小鼠原代肝细胞对Ins的敏感性降低。BEL-7404细胞经T短时间(1 h)处理后,Ins对细胞中糖原合成率以及Akt和GSK3β蛋白活性的诱导作用显著提高(P0.05);但当BEL-7404细胞经高浓度T(10~(-5) mol/L)长时间(36 h)处理后,Ins对细胞中糖原合成率以及Akt和GSK3β蛋白活性的诱导作用显著降低(P0.05),提示高浓度T在短时间内能增强BEL-7404细胞对Ins的敏感性,但长时间暴露后会降低细胞对Ins的敏感性。结论:长时间的T暴露可能会降低肝细胞中Ins信号转导活性,从而干扰肝细胞对Ins的敏感性,导致IR的产生。     

Food Poisonings by Ingestion of Cyprinid Fish

Raw or dried gallbladders of cyprinid fish have long been ingested as a traditional medicine in the Asian countries, particularly in China, for ameliorating visual acuity, rheumatism, and general health; however, sporadic poisoning incidences have occurred after their ingestion. The poisoning causes complex symptoms in patients, including acute renal failure, liver dysfunction, paralysis, and convulsions of limbs. The causative substance for the poisoning was isolated, and its basic properties were examined. The purified toxin revealed a minimum lethal dose of 2.6 mg/20 g in mouse, when injected intraperitoneally. The main symptoms were paralysis and convulsions of the hind legs, along with other neurological signs. Liver biopsy of the euthanized mice clearly exhibited hepatocytes necrosis and infiltration of neutrophils and lymphocytes, suggesting the acute dysfunction of the liver. Blood tests disclosed the characteristics of acute renal failure and liver injury. Infrared (IR) spectrometry, fast atom bombardment (FAB) mass spectrometry, and ¹H- and ¹³C-nuclear magnetic resonance (NMR) analysis indicated, a molecular formula of C₂₇H₄₈O₈S, containing a sulfate ester group for the toxin. Thus, we concluded that the structure of carp toxin to be 5α-cyprinol sulfate (5α-cholestane-3α, 7α, 12α, 26, 27-pentol 26-sulfate). This indicated that carp toxin is a nephro- and hepato- toxin, which could be the responsible toxin for carp bile poisoning in humans.     

Subclinical hypothyroidism is associated with metabolic syndrome and clomiphene citrate resistance in women with polycystic ovary syndrome

Background: To evaluate the possible relationship between subclinical hypothyroidism (SCH) and metabolic syndrome (MS) and the response to clomiphene citrate (CC) stimulation in women with polycystic ovary syndrome (PCOS).

Methods: One hundred and ninety-six women with PCOS were divided into two groups: (1) the SCH group with 92 patients; (2) the euthyroid (EU) group with 104 patients. Physical characteristics and metabolic parameters as well as the reaction to CC stimulating test were compared between these two groups.

Results: (1) In the SCH group, significantly higher body mass index, Ferriman–Gallwey score, serum triglyceride, insulin and glucose of oral glucose tolerance test, homeostatic model assessment-insulin resistance (HOMA-IR) and significantly lower serum high-density lipoprotein cholesterol was observed in comparison with those in the EU group (p?IR (43.5%) and MS (34.8%) in the SCH group was significantly higher than that in the EU group (p < 0.05).

Conclusions: SCH was found associated with IR, MS and CC resistance in women with PCOS. PCOS patients with SCH may have a poorer treatment response to ovulation induction with CC.     

Sacchachitin,a novel chitin-polysaccharide conjugate macromolecule present in Ganoderma lucidum: Purification,composition, and properties

Context: The extraction method and the crude wound healing effects of sacchachitin from Ganoderma tsugae Murr. (Ganodermataceae) has been cited. However, its purity is still largely limited.

Objective: An improvement of the fractionation protocol to purify the sacchachitin from Ganoderma lucidum L. (Ganodermataceae) (SGL) is needed.

Methods: Fruiting bodies were extracted with double distilled water and subsequently the residue treated with 95% ethanol and then 40% ethanol. After being filtered, the pH of the supernatant was adjusted to 4.0 with 1 N HCl and lyophilized. The supernatant was added (3:1 v/v) ethanol, the precipitate was collected, 2% NaOH was added and refluxed. The supernatant was collected with pH adjusted to 4.0, then treated with 10% potassium hydroxide (KOH) with repeating acid precipitation and (3:1) ethanol precipitation twice more to obtain the sacchachitin.

Results: SGL had a hexosamine content 16.3% (w/w), firmly linked to a talomannan. Its Fourier Transform Infrared Spectroscopy (FTIR) spectrum revealed specific absorption (in cm^–1) ν_O–H 3455.5 b,s, amide ν_C=O 1678.5, and amide I° δ_N–H 1550.4. The percentage deacetylation degree was 37.6 and 39.4% for SGL and MSC, respectively. As contrast, MSC contained only 6.6% of hexosamine with a low protein/carbohydrate ratio 0.35 comparing to 0.82 for SGL. SGL was only moderately strong antioxidant regarding the anti-DPPH, antihydroxyl free radical, and antisuperoxide anion capabilities, exhibiting an IC₃₃ values of 10?mg/mL (the highest scavenging capability never exceeding 33%), 0.9?mg/mL, and 4.8?mg/mL, respectively.

Conclusion: We have successfully isolated the pure sacchachitin from the fruiting bodies of G. lucidum that exhibits potent antioxidative activity and may be useful in fabrication of the artificial skin composite substitute.     

Advances in understanding the molecular basis of the first steps in color vision

Serving as one of our primary environmental inputs, vision is the most sophisticated sensory system in humans. Here, we present recent findings derived from energetics, genetics and physiology that provide a more advanced understanding of color perception in mammals. Energetics of cis–trans isomerization of 11-cis-retinal accounts for color perception in the narrow region of the electromagnetic spectrum and how human eyes can absorb light in the near infrared (IR) range. Structural homology models of visual pigments reveal complex interactions of the protein moieties with the light sensitive chromophore 11-cis-retinal and that certain color blinding mutations impair secondary structural elements of these G protein-coupled receptors (GPCRs). Finally, we identify unsolved critical aspects of color tuning that require future investigation.     

孕产妇复发性流产与胰岛素抵抗相关性Meta分析

目的：对国内外发表的随机病例对照研究文章进行Meta分析,力图探明胰岛素抵抗( IR)是否增加孕产妇复发性流产( RSA)的风险。方法使用计算机检索PubMed、Embase、Springer Link、中国生物医学文献数据库等数据库及手工检索相关期刊内自1996年1月至2014年1月之间发表的有关于RSA与IR关系的病例对照研究类国内外文献,按既定标准筛选后对入组文献进行质量评分,并使用Meta分析探究两者间关系。结果分析中共计6篇国内外文献选入研究范围,RSA组共计432例孕产妇,对照组共计383例(均未见不良孕产史)。分析提示,两组孕产妇在空腹血糖水平差异无统计学意义的前提下,出现了RSA组患者空腹胰岛素数值相对升高及RSA组患者的胰岛β细胞功能受损较对照组严重;且RSA组患者的IR指数较对照组高,即IR指数>4.5的患者大多来自RSA组,差异具有统计学意义(OR=3.16,95%CI为1.7~6.8,I2=1.157,P<0.05)。结论 IR与RSA间存在一定相关性,其可能为RSA的原因之一。     

Dark-Blood Delayed Enhancement Cardiac Magnetic Resonance of Myocardial Infarction

Objectives

This study introduced and validated a novel flow-independent delayed enhancement technique that shows hyperenhanced myocardium while simultaneously suppressing blood-pool signal.

芹菜素γ-环糊精包合物的表征和抗氧化活性研究

目的研究芹菜素与γ-环糊精(γ-CD)包合物的制备、表征、包合机制及其抗氧化活性。方法采用加热回流共沉淀法制备芹菜素γ-环糊精包合物,红外光谱法(IR)对形成的包合物进行表征,荧光光谱法测定包合物的包合常数(K)和包合比(n);荧光光谱法和核磁共振法(NMR)研究芹菜素与γ-CD在溶液中形成的包合物;双倒数曲线法研究包合前后对自由基1,1-二苯基-2-三硝基苯肼(DPPH·)的清除率。结果在不同的pH值溶液中,γ-CD对芹菜素具有不同的包合能力,γ-CD最适合在中性介质中与芹菜素形成包合物,在实验浓度范围内按1∶1形成包合物,包合比为1236,包合物对自由基DPPH·的清除活性更强;NMR确定包合物的结构。结论在实验条件下,芹菜素分子从γ-CD大口端进入到空腔内形成稳定的包合物,且抗氧化活性增加。