V3 sequence analysis and biological characterization of HIV-1 isolates from asymptomatic and early symptomatic Tanzanian individuals

The aim of this study was to determine HIV-1 V3 sequences, in vitro biological characteristics and co-receptor usage of virus isolates from Tanzania. Virus was isolated from 14 of 17 samples investigated. Four of the isolates induced syncytia in MT-2 cells and used the CXCR4 co-receptor, while the remaining 10 isolates used the CCR5 co-receptor characteristic of non-MT-2 tropic viruses. One of the four MT-2 tropic isolates also used the CCR5 and CCR3 co-receptors. Proviral DNA was detected in all 14 isolates and PCR products were subjected to DNA sequencing. Unambiguous V3 amino acid sequences were obtained from 11 amplificates. Phylogenetic analysis indicated that these sequences were divergent and clustered in HIV-1 subtypes A, C or D. Sequences from the viruses that induced syncytia in MT-2 cells presented characteristic V3 phenotype-associated amino acids. Results of co-receptor analysis are in concordance with the isolate phenotype as determined by replication and induction of syncytia in MT-2 cells. The considerable diversity illustrated by a limited number of isolates from Tanzania is in accordance with reports from other regions of Africa.     

Diversity of Hepatitis G Virus within a Single Infected Individual

The extent of population diversity among GB virus C (GBV-C)/hepatitis G virus (HGV) within a persistently infected individual (Iw) was investigated by sequence analysis of multiple clones generated from polymerase chain reaction (PCR)-amplified products of cDNA analogous to fragments of 5 non-coding region (5NC), envelope region 1/2 (E1/E2) and non-structural region 3 (NS3) of viral genome. Although nucleotide substitutions were more common in coding regions than in the 5NC region, there was no region corresponding to the hypervariable region of hepatitis C virus in the E1/E2 region. Transition substitution exceeded transversion by 7 to 12-fold, and 79.4% of substitutions were synonymous. This bias against substitutions producing amino acid replacements and the use of Pfu DNA polymerase with an error rate 10 times lower than the observed frequency of substitution, suggests that most substitutions were not artefactual. This data suggests that individual genomes of HGV within an infected individual may differ from each other at 0.23–0.84% nucleotide position and at 0.42–0.61% amino acid position.     

热力学模型对石油低压汽液平衡计算的适用性

以Maxwell-Bonnel图拟合式、对比态Antoine方程及Pitzer-Riedel关联式分别求算饱和蒸汽压P^0,并用RoultK值（K＝P^0／P）,计算窄留分K值。根据实测的中原、孤岛和克拉玛依石油馏分低压K值,考察上述三式,结果表明：对比态Antoine式预测精度是最好的,其温度预测绝对平均偏差为7．0℃,K值预测平均相对偏差为15．6％,其他两模型偏差均较大。     

Interphotoreceptor Retinol-Binding Protein Ameliorates Diabetes-Induced Retinal Dysfunction and Neurodegeneration Through Rhodopsin

Patients with diabetes often experience visual defects before any retinal pathologies are detected. The molecular mechanism for the visual defects in early diabetes has not been elucidated. Our previous study reported that in early diabetic retinopathy (DR), rhodopsin levels were reduced due to impaired 11-cis-retinal regeneration. Interphotoreceptor retinol-binding protein (IRBP) is a visual cycle protein and important for 11-cis-retinal generation. IRBP levels are decreased in the vitreous and retina of DR patients and animal models. To determine the role of IRBP downregulation in the visual defects in early DR, we induced diabetes in transgenic mice overexpressing IRBP in the retina. IRBP overexpression prevented diabetes-induced decline of retinal function. Furthermore, IRBP overexpression also prevented decreases of rhodopsin levels and 11-cis-retinal generation in diabetic mice. Diabetic IRBP transgenic mice also showed ameliorated retinal oxidative stress, inflammation, apoptosis, and retinal degeneration compared with diabetic wild-type mice. These findings suggest that diabetes-induced IRBP downregulation impairs the regeneration of 11-cis-retinal and rhodopsin, leading to retinal dysfunction in early DR. Furthermore, increased 11-cis-retinal–free opsin constitutively activates the phototransduction pathway, leading to increased oxidative stress and retinal neurodegeneration. Therefore, restored IRBP expression in the diabetic retina may confer a protective effect against retinal degeneration in DR.     

儿童臀肌挛缩症免疫发病机理的研究

本文对４１例儿童臀肌挛缩症患者外周血及３２例儿童臀肌挛缩症臀肌进行了系统的免疫学研究。结果表明：儿童臀肌挛缩症患者免疫调节功能紊乱，红细胞免疫功能低下，臀肌组织免疫复合物沉积，臀肌小血管数目减少及管壁损伤。由此认为免疫病理因素是儿童臀肌挛缩症的主要发病机理。     

小脑和脑干梗塞致突发性耳聋

目的:了解小脑和脑干梗塞引起的突发性耳聋的临床特点.探讨其发病机制.方法:回顾性分析12例小脑和脑干梗塞所致突发性耳聋的临床资料.结果:该组患者主要临床表现为耳聋、眩晕、耳鸣、眼震、同侧颜面麻木感.头颅CT或MRI发现小脑或脑干有小于2 cm的梗塞灶.结论:发病机制主要为小脑前下动脉(AlCA)供血不足使小脑脑桥角或脑干缺血,损伤该区域的耳蜗神经和听神经传导通路,导致耳聋.小脑和脑干梗塞的诊断主要依据临床表现、CT或MRI检查.     

冠状动脉粥样硬化性心脏病的当代治疗

0　引言冠状动脉粥样硬化性心脏病(简称冠心病)治疗在20世纪60年代以前是药物治疗为主,到了20世纪70年代,外科采用冠状动脉旁路术开辟了冠心病治疗的新途径.进入20世纪80年代,冠状动脉旁路术在西方发达国家已经非常成熟,非常普遍.同时期,内科介入治疗也迅速发展起来,下面就各种治疗方法的进展分别进行讨论.1　内科治疗1.1　药物治疗　冠心病的药物治疗随着患者病情不同而不同.对一般常有心绞痛发作的患者常用药物主要有两类,一类是扩张冠状动脉血管,减轻心脏缺血,缓解或预防心绞痛.这类药物主要有硝酸盐制剂,如硝酸甘油、亚硝酸异戊酯、四硝…     

肢端型系统性硬皮病误诊1例

1　病例报告　女 ,45岁 ,因吞咽困难 16 mo伴发热 15 d,于1999- 0 7- 12入院 .于 16 mo前与人争吵后出现吞咽困难 ,以进食馒头、面条为著 ,剑突下有时出现梗噎感 ,随即呕吐 ,呕出所进食物及粘液 ,情绪波动可诱发症状加重 ,伴食欲减退、返酸 .15 d前无诱因出现不规则发热 ,T38～ 39℃ ,上腹痛加重 ,全身酸困不适 ,乏力、头晕、消瘦 .追问病史 ,患者 5 a前双手、足疼痛麻木 ,尤以受凉、精神刺激后明显 ,手指初发白 ,继而发紫 ,变红 ,且麻木疼痛加重 ,手足小关节渐僵硬、畸形 .曾到多家医院就诊 ,诊断 :“雷诺病、类风湿性关节炎”.2 a前出现…     

运用原位DNA末端标记法研究细胞凋亡对乳腺癌预后的影响

研究临床乳腺癌标本中细胞凋亡的发生情况,评价其在预测后在的意义。方法搜集９１例浸润性乳腺癌的石蜡组织切片,运用原位ＤＮＡ断裂位点的末端标记法,检测细胞凋亡,计算凋亡细胞占肿瘤细胞的百分比,求得凋亡指数。结果本组病例细胞凋亡发生率为９１．２％,凋亡指数分为两组：０～０．２１和０．２８～０．６２,凋亡指数高低与腋淋巴结转称相关（Ｐ＜０．０１）。生存率单因素分析中,凋亡指数高的病例,无病生存率（Ｐ＝０．００９５）及总生存率（Ｐ＝０．０３４８）均优于凋亡指数低的病例。但Ｃｏｘ模型多因素分析末能指示凋亡指数是一个独立的预后指标。结论在乳腺癌组织中,细胞凋亡是一种自发现象,其发生情况各有不同,研究初步提示了细胞凋亡在乳腺癌预后中的作用,了解了凋亡和腋淋巴结转移的相关性。