Postmenopausal hormone therapy and cardiovascular disease: Making sense of the evidence

Controversy surrounding the cardioprotective role of postmenopausal hormone therapy continues. This controversy is fueled in part by the body of evidence that indicates a duality of hormone therapy on potential risks and benefits. The totality of evidence indicates that the effects of postmenopausal hormone therapy are affected by age, state of the target tissue, duration of therapy, and timing of initiation, according to time since menopause. This review presents evidence supporting a cardioprotective role of hormone therapy in young postmenopausal women as well as a potentially negative effect in older postmenopausal women. These data are reviewed in relation to the evidence that hormone therapy prevents new onset diabetes mellitus, and that the risks of hormone therapy are rare and even rarer in young postmenopausal women. The cardioprotective role of postmenopausal hormone therapy will only be resolved by refined research guided by the results from previous studies.     

Cholesterol oxidation products induce vascular foam cell lesion formation in hypercholesterolemic New Zealand white rabbits.

Circulating cholesterol oxidation products (ChOx) have long been implicated in the etiology of early atherosclerosis; however, direct in vivo evidence elucidating their role in atherogenesis is only recently becoming available. This study investigated ChOx effects on vascular lesion formation in New Zealand White rabbits under controlled hypercholesterolemic conditions. By closely monitoring plasma cholesterol levels and adjusting dietary cholesterol intake during a 78-day period, total plasma cholesterol exposures (cumulative plasma cholesterol levels over time) were controlled between 27 000 and 34 000 mg/dLxday (final plasma cholesterol concentration, 467+/-77 mg/mL), representing a threshold range for sudanophilic lesion formation in the aorta. Twenty injections of a ChOx mixture (70 mg per injection) were made bearing an oxysterol composition similar to that found in circulating oxidatively modified low density lipoprotein. At sacrifice, the ChOx-injected rabbits (n=5) had (1) significantly higher plasma ChOx levels, (2) significantly increased cholesterol content in the aortas, mainly as esterified cholesterol, and (3) significantly greater sudanophilic lesion size and frequency in the aortas compared with vehicle-injected control rabbits (n=5). The aortic cholesterol content and extent of sudanophilic lesion area were correlated significantly with total plasma ChOx exposure (P<0.003 and P<0.0001, respectively) but not with total cholesterol exposure. The results indicate that for moderate experimental hypercholesterolemia, a situation more relevant to physiological hypercholesterolemia in humans, circulating ChOx may play an important role in inducing formation of early atherosclerotic lesions. Because ChOx are often present in cholesterol-containing diets, foam cell lesion formation induced by ChOx rather than cholesterol cannot be overlooked.     

Revised and updated nomenclature for highly pathogenic avian influenza A (H5N1) viruses

The divergence of the hemagglutinin gene of A/goose/Guangdong/1/1996‐lineage H5N1 viruses during 2011 and 2012 (807 new sequences collected through December 31, 2012) was analyzed by phylogenetic and p‐distance methods to define new clades using the pre‐established nomenclature system. Eight new clade designations were recommended based on division of clade 1·1 (Mekong River Delta), 2·1·3·2 (Indonesia), 2·2·2 (India/Bangladesh), 2·2·1·1 (Egypt/Israel), and 2·3·2·1 (Asia). A simplification to the previously defined criteria, which adds a letter rather than number to the right‐most digit of fifth‐order clades, was proposed to facilitate this and future updates.     

The identification of urinary bile alcohols by gas chromatography–mass spectrometry in patients with liver disease and in healthy individuals

Abstract. The neutral steroid fractions in the urine of eleven patients suffering from various forms of liver disease with cholestasis and of ten healthy individuals were studied by glass capillary gas chromatography-mass spectrometry. The steroid conjugates in urine were enzymatically solvolysed, the liberated steroids extracted and transformed into the trimethylsilylether for measurements.
The excretion rates of androstane and pregnane metabolites of patients with liver disease were far lower than those of healthy persons. The main compounds in the urine of the former were the bile alcohols 27 - nor -3α, 7α, 12α, 24, 25 - pentahydroxy - 5β - cholestane and 3α, 7α, 12α, 25, 26 - pentahydroxy - 5β - cholestane. Our data suggest a correlation between the excretion rates of these bile alcohols and the serum levels of bilirubin. While the excretion rate of the two bile alcohols in the urine of healthy individuals was approximately 0.24 mg/24 h (0.6 μmol/24 h) a patient with a serum bilirubin of 841 μmol/1 excreted 4 mg/24 h (9 μmol/24 h). The accumulation of bile alcohols described in this study possibly indicates alternative pathways of cholic acid formation in liver disease.     

Pre-S2抗原在乙肝病毒隐性感染中的地位与应用研究

探讨Pre-S2抗原在乙型肝炎病毒的各类隐性感染中的地位及科研、临床应用价值。以乙肝病毒隐性感染者作为研究对象,采用ELISA法,同时检测感染者的Pre-S2抗原和“乙肝血清标志物(HBV M)”,然后进行各类感染者之间的比较、分析。在乙肝病毒隐性感染者人群中,HBeAg阳性者、HBeAb阳性者的Pre-S2抗原阳性率分别为93．10％、60．00％;“乙肝大三阳”、“小三阳”者的Pre-S2抗原阳性率分别为92．31％、62．50％。Pre-S2抗原在判断乙肝病毒复制、隐性感染者血清的传染性强度方面,有很高使用价值和补缺作用;在判断隐性感染者的发展转化方面,亦有重大参考意义。     

Predominant role of catalase in the disposal of hydrogen peroxide within human erythrocytes

Purified enzymes were mixed to form a cell-free system that simulated the conditions for removal of hydrogen peroxide within human erythrocytes. Human glutathione peroxidase disposed of hydrogen peroxide (H2O2) at a rate that was only 17% of the rate at which human catalase simultaneously removed hydrogen peroxide. The relative rates observed were in agreement with the relative rates predicted from the kinetic constants of the two enzymes. These results confirm two earlier studies on intact erythrocytes, which refuted the notion that glutathione peroxidase is the primary enzyme for removal of hydrogen peroxide within erythrocytes. The present findings differ from the results with intact cells, however, in showing that glutathione peroxidase accounts for even less than 50% of the removal of hydrogen peroxide. A means is proposed for calculating the relative contribution of glutathione peroxidase and catalase in other cells and species. The present results raise the possibility that the major function of glutathione peroxidase may be the disposal of organic peroxides rather than the removal of hydrogen peroxide.     

世界华人消化杂志现状及未来发展的目标

0引言《世界华人消化杂志》创刊于1993-01-15,原刊名《新消化病学杂志》,1999-03-25经国家科学技术部和国家新闻出版总署批准更名为《世界华人消化杂志》．《世界华人消化杂志》综合介绍消化病学前沿基础与临床研究的发现,覆盖消化病学领域中经临床实验证明的技术进展．经历了近14 a的发展,本刊在以下几个方面取得了长足的进步．