Delivery of a hammerhead ribozyme specifically down-regulates the production of fibrillin-1 by cultured dermal fibroblasts

The hammerhead ribozyme is a small catalytic RNA molecule. Potential hammerhead ribozymes that possess a catalytic domain and flanking sequence complementary to a target mRNA can cleave in trans at a putative cleavage site within the target molecule. We have investigated the potential of hammerhead ribozymes to down-regulate the product of the fibrillin-1 gene (FBN1). Fibrillin is a 347 kDa glycoprotein that is a major constituent of the elastin-associated microfibrils. Mutations in the FBN1 gene are responsible for Marfan syndrome (MFS), a common systemic disorder of the connective tissue. Many FBN1 mutations responsible for MFS appear to act in a dominant-negative fashion, raising the possibility that reduction of the amount of product from the mutant FBN1 allele might be a valid therapeutic approach for MFS. A trans-acting hammerhead ribozyme (FBN1-RZ1) targeted to the 5' end of the human FBN1 mRNA has been designed and synthesized, and shown to cleave its target efficiently in vitro. FBN1-RZ1 cleavage is magnesium dependent and efficient at both 37 and 50 degrees C. Delivery of the FBN1-RZ1 ribozyme into cultured dermal fibroblasts, by receptor- mediated endocytosis of a ribozyme-transferrin-polylysine complex, specifically reduces both cellular FBN1 mRNA and the deposition of fibrillin in the extracellular matrix. These results suggest that the use of hammerhead ribozymes is a valid approach to the study of fibrillin gene expression and possibly to the development of a therapeutic approach to MFS.      

Elevation of plasma thioredoxin levels in HIV-infected individuals

Thioredoxin (Trx), a ubiquitous protein intimately involvedin redox and protein disulfide reductions, has been shown tobe released from cells and to have cytokine-like activities.In addition, Trx has been implicated in the redox regulationof immunological responses and shown to be deficient in tissuesfrom AIDS patients. In studies presented here, plasma Trx levelswere measured by ELISA in plasma samples from HIV-infected individuals(n = 136) and HIV-negative controls (n = 47). To account forthe release of Trx into plasma due to hemolysis, the Trx measurementswere corrected according to the level of hemoglobin in the plasmasample. Data presented show that, in contrast to tissue Trxlevels, corrected plasma Trx levels are significantly higherin HIV-infected individuals than in controls (P < 0.0001).Furthermore, {small tilde}25% of the HIV-infected individualsstudied have plasma Trx levels greater than the highest levelfound in controls (37 ng/ml). Detailed multiparameter FACS analysisof peripheral blood mononuclear cells (PBMC) from the infectedindividuals demonstrates that those with higher plasma Trx levels(37 ng/ml or greater) tend to have lower overall CD4 counts.In addition, increases in plasma Trx levels correlate with decreasesin monochlorobimane staining (indicative of lower intracellularglutathione levels in PBMC) and with changes in surface antigenexpression (CD62L, CD38 and CD20) that occur in the later stagesof HIV infection. These correlations suggest that elevationof plasma Trx levels may be an important component of advancedHIV disease, perhaps related to the oxidative stress that oftenoccurs at this stage.     

Viral Persistence in Neurons Alters Synaptic Plasticity and Cognitive Functions without Destruction of Brain Cells

Neurons have a restricted expression of MHC heavy chain molecules which prevents presentation of antigens of infecting viruses. As a result, such infected cells escape immune surveillance and allow the establishment of noncytolytic persistent infection. Here we show that a chronic noncytolytic viral infection bothin vitroandin vivoselectively perturbed the expression of GAP-43, a protein that plays a central role in neuronal plasticity processes accompanying learning and memory. GAP-43 expression was greatly decreased in the hippocampus, an area of heightened viral replication, while synaptic density was preserved. Concurrently, the ability to learn tasks was significantly impaired in these persistently infected mice. Yet, infected neurons remained free from structural injury.     

反复种植失败的相关对策新进展

辅助生殖技术的迅速发展使众多不孕症患者借助体外受精-胚胎移植(IVF-ET)及其衍生技术获得了后代。然而很大一部分妇女经历多次优质胚胎移植亦不能获得妊娠,反复种植失败(RIF)已经成为阻碍妊娠率进一步提高的瓶颈问题,且日益受到生殖医学界的广泛关注。就目前的条件而言,对RIF患者给予药物或者机械操作以提高子宫内膜容受性,行宫腹腔镜检查排除宫腔及盆腔病变以改善胚胎种植环境,通过辅助孵化、选择性囊胚移植、植入前胚胎遗传学筛查、共培养等技术提高胚胎着床能力都有可能改善和提高其种植率及妊娠率。RIF成为了我们亟待解决的问题,现综述近年有关反复种植失败的相关对策新进展。     

Loss of angiotensin-converting enzyme-2 (Ace2) accelerates diabetic kidney injury

Diabetic nephropathy is one of the most common causes of end-stage renal failure, but the factors responsible for the development of diabetic nephropathy have not been fully elucidated. We examined the effect of deletion of the angiotensin-convert-ing enzyme 2 (Ace2) gene on diabetic kidney injury. Ace2(-/-) mice were crossed with Akita mice (Ins2(WT/C96Y)), a model of type 1 diabetes mellitus, and four groups of mice were studied at 3 months of age: Ace2(+/y)Ins2(WT/WT), Ace2(-/y)Ins2(WT/WT), Ace2(+/y) Ins2(WT/C96Y), and Ace2(-/y)Ins2(WT/C96Y). Ace2(-/y) Ins2(WT/C96Y) mice exhibited a twofold increase in the urinary albumin excretion rate compared with Ace2(+/y)Ins2(WT/C96Y) mice despite similar blood glucose levels. Ace2(-/y)Ins2(WT/C96Y) mice were the only group to exhibit increased mesangial matrix scores and glomerular basement membrane thicknesses compared with Ace2(+/y)Ins2(WT/WT) mice, accompanied by increased fibronectin and alpha-smooth muscle actin immunostaining in the glomeruli of Ace2(-/y) Ins2(WT/C96Y) mice. There were no differences in blood pressure or heart function to account for the exacerbation of kidney injury. Although kidney levels of angiotensin (Ang) II were not increased in the diabetic mice, treatment with an Ang II receptor blocker reduced urinary albumin excretion rate in Ace2(-/y)Ins2(WT/C96Y) mice, suggesting that acceleration of kidney injury in these mice is Ang II-mediated. We conclude that ACE2 plays a protective role in the diabetic kidney, and ACE2 is an important determinant of diabetic nephropathy.     

经颅多谱勒超声在位置性缺血性眩晕中的应用

目的:探讨经颅多谱勒超声(TCD)在颈椎病(椎动脉型)所致位置性缺血性眩晕中的诊断价值.方法:利用TCD对颈椎病所致位置性缺血性眩晕76例患者进行双侧大脑后动脉(PCA)的平均血流速度分析,并结合转颈试验,探测双侧PCA平均血流速的动态变化情况.结果:颈椎病所致位置性缺血性眩晕患者当头侧向转动时,双侧PCA的平均血流速度暂时性降低,当头转回中立位时,平均血流速度逐渐回升.结论:TCD有助于识别位置性眩晕中的真性位置性缺血患者,是一种无创、简便、价廉、可靠,并可床旁操作和提供实时动态血流动力学资料的重要检查方法.     

内蒙古自治区智力残疾现患率调查及病因分析

目的:了解内蒙古自治区智力残疾(mental retardation.MR)的现患率及其分布特点,分析其主要致残原因构成特点,探讨预防治疗措施。方法:采用概率比例、多阶段分层整群抽样方法进行现况调查及病例对照研究,根据年龄分别使用丹佛发育筛查测验及《7岁以上人群残疾筛查问卷》筛查,分别使用Gesell发育诊断量表及韦氏儿童智力量表简式(WISC-CR),韦氏成人智力量表简式(WAIS-RC)进行智力诊断,采用SPSS11.0软件对数据进行统计分析。结果:①内蒙古自治区智力残疾患者的现患率为4.95‰,男性MR现患率高于女性(χ2=6.28,df=1,P<0.05),农村MR的现患率明显高于城市(χ2=60.035,df=1,P<0.01)。②内蒙古自治区智力残疾致残原因以疾病(29.26%)和遗传因素(23.79%)为主。③在18岁之前(智力发育期)发现智力残疾的占74.53%,且以0~3岁发现智力残疾的人数比例最高(48.84%)。结论:智力残疾的防治重点应在农村,预防应以疾病(主要包括脑疾病、内分泌障碍、惊厥性疾病)及遗传因素为主。强调早期发现、早期干预。     

Ten-year survival in 290 patients with endometrial cancer: prognostic factors and therapeutic approach

Summary. Between 1970 and 1976, 290 patients with endometrial cancer were treated at the 1st Obstetrics and Gynecology Clinic of the University of Milan. The median age was 62 years. Surgery was completed in 262 (90.3%) patients. Abdominal hysterectomy was used in 158 (70.9%) stage I and 40 (71.4%) stage II/III patients; vaginal hysterectomy in 55 (24.7%) stage I and nine (16.1%) stage II/III patients. Resection of the upper vagina was performed in 168 patients. Postoperative external beam radiotherapy was used in stage II/III patients and in 44 (19.7%) stage I high-risk patients. Ten-year survival, determined by the life-table method, was 84.8% in stage I (223 patients), 53.4% in stage II (37 patients), 64.4% in stage III (19 patients), and 9.1% in stage IV (11 patients). Factors associated with poorer prognosis were: late age at diagnosis (P<0.001); deep myometrial invasion (P<0.001); poorly differentiated histological grade ( P =0.11); lack of resection of the upper vagina ( P = 0.13). The role and importance of surgery is discussed, with special emphasis on the selective use of the vaginal route in aged, obese and medically high-risk patients.