DNA diagnosis of FRAXA and FRAXE in Chinese children with neurodevelopmental disorders and fragile X syndrome

Fragile X (FraX) syndrome is the most common cause of inherited mental retardation. To see whether FRAXA or FRAXE can account for the etiology of some unexplained neurodevelopmental disorders in children, we screened for trinucleotide repeat expansion in a consecutive cohort of 73 Chinese children and their mothers seen in 1995 (group 1) referred for developmental assessment due to developmental delay, language delay, attention deficit hyperactivity disorder, autistic spectrum disorder, mental retardation and/or learning disability. We also screened DNA samples of all five previously diagnosed cytogenetically-positive FraX boys, their mothers and sisters (group 2). A control group of unrelated teenagers and adults were recruited from the community (group 3). In group 1, 3 families (2 mothers and a mother and her son) were found to carry a small premutation allele at FRAXA (premutation frequency = 2%, 3/153 independent X chromosomes), but none had any expansion at FRAXE. In group 2, all 5 FraX boys had full mutation at FRAXA and normal repeat length at FRAXE. In group 3, 1 male has a premutation allele out of 18 males and 59 females tested (premutation frequency of control = 0.7%, 1 out of 136 X chromosomes). For FRAXE screening in group 3, 2 females were carriers (1.5%, 2 out of 136 X chromosomes). Thus, FRAXA and FRAXE cannot account for the etiology of neurodevelopmental disorders in our cohort of Chinese children, and the prevalence of FRAXE mutation in normal Chinese population appears to be higher than reported in the Caucasians.     

Assessment of congenital heart defects by dynamic three-dimensional echocardiography: methods of data acquisition and clinical potential

To evaluate the use of three-dimensional (3D) echocardiography in the diagnosis of congenital heart defects, we studied 238 patients aged 3 days to 19 years (mean 4.3 years) with normal hearts ( n = 13) or a variety of congenital heart defects (n = 225) Three different modalities of data acquisition suitable for reconstruction were applied For parallel scanning, the transducer is held in a 6-cm long scan frame and then moved over the thorax, or in the subcostal position, by a stepper motor using 0.5-mm steps with acquisition of perpendicular parallel images of the heart For rotational scanning, the transducer is rotated at sectors of 2° over a span of 180° For fan-like scanning, the transducer is moved in an arc 45° each way from its vertical axis Movement of the transducer is computer-controlled and performed with electrocardiography and respiratory gating Between 80 and 120 slices of the heart are thus obtained, which form the dataset This dataset can then be "sectioned" in any desired plane, thus permitting generation of views simulating intraoperative perspectives Ventricular septal defects and atrioventricular valves can be displayed as viewed via the atrium Muscular ventricular septal defects can be viewed as seen through a ventriculotomy Obstruction in the left ventricular outflow tract can be viewed as via an aortotomy, and so on We conclude that this new imaging modality has a vast potential and may facilitate planning of intracranial surgery.     

Different Effects of Estrogen and Progesterone on K+ Currents Expressed in Xenopus Oocytes

Estrogen has received considerable attention recently as a potential therapeutic agent in vascular pathophysiological states such as stroke. The mechanisms by which estrogen influences cerebral arteries are incompletely understood. The present study was to examine the effect of ovariectomy and chronic estrogen or tamoxifen treatment on vascular reactivity in rat posterior communicating cerebral arteries with intact endothelium. Changes in vascular tension were measured by microvessel myograph. Ovariectomy significantly enhanced the constricting responses to endothelin I, but not to phenylephrine. Chronic treatment with estrogen or tamoxifen partially reversed or abolished the effect of ovariectomy. The contraction induced by high K⁺ solution was also enhanced in the ovariectomized rats and this enhancement was abolished by estrogen or tamoxifen treatment. Ovariectomy potentiated the relaxant response to nicardipine but not NS 1619. Estrogen but not tamoxifen reversed the effect of ovariectomy. The present results indicate that chronic tamoxifen may not act as an antagonist of estrogen, instead, chronic treatment with estrogen and tamoxifen has similar effect in inhibiting the increased vascular tension induced by ovariectomy. This study suggests the influence of physiological level of estrogen on vascular contractility. It is at present unknown what may have caused increased relaxant effect of nicardipine, a L-type Ca²⁺ channel blocker. More experiments are needed to show the role of endothelium in the altered vascular contractility in the ovariectomized and estrogen-treated rats. (supported by UPGC Direct Grant).     

中国香港与西方儿童分泌性中耳炎发病率的比较

目的 调查中国香港儿童分泌性中耳炎发病率,并且进一步与西方的研究结果做比较。方法 1995-1998年,在中国香港特别行政区随机抽取小学、幼稚园(4-5岁)及幼儿园(2-3岁),对6872名2-7岁儿童进行检查,在校内接受由耳鼻咽喉科专家施行的耳镜检查及由听力学家执行的鼓室导抗测试。为了与西方研究结果作出标准化的比较,根据他们所采用的诊断标准重新计算。结果 在划分为2-3岁、4-5岁及6-7岁的研究对象中,若以耳镜临床诊断作标准,本研究分泌性中耳炎发病率为5.2％-21.6％;若以鼓室导抗图作诊断标准,发病率为7.3％-30.7％。同一组数据,发病率计算结果是会因为采用不同的鼓室导抗图诊断定义而有偏差,但无论是用哪种方法,结果都与西方同龄研究的发病率差异无显著性,而且发病率随年龄增加而下降。结论 香港2-3岁、4-5岁,及6-7岁中国儿童的分泌性中耳炎发病率与西方文献报告没有显著性差异。     

脂肪族聚氨酯弹性体肝素化的血液相容性

目的:改进脂肪族聚氨酯(polyurethane,PU)弹性体表面接枝肝素(heparin,Hep)的工艺过程,观察共价键合法接枝肝素后其血液相容性。方法:实验于2005-08/2006-08于同济大学材料科学与工程学院实验室完成。材料制备:①脂肪族聚氨酯的合成:采用一步法合成以4,4'-甲烷二苯基二异氰酸酯(HMDI)或异氟尔酮二异氰酸醑(IPDI)、扩链剂1,4-丁二醇为硬段,聚四氢呋喃醚为软段的脂肪族聚氨酯,分别生成IPDI型聚氨酯和HMDI型聚氨酯。②共价键合法聚氨酯表面接枝肝素:形成PU-Hep,PU-聚乙烯醇(polyvinylalcohol,PVA)-Hep,PU-聚乙二醇(polyethyleneglycol,PEO)-Hep,PU-PVA-PEO-Hep中间产物。实验评估:①接枝肝素含量的测定:甲苯胺蓝显色法测定聚氨酯表面的肝素含量;甲苯胺蓝分光光度法测定肝素释放速率。②肝素接枝表面的血液相容性测定:通过溶血实验和血小板黏附实验测定。结果:①聚氨酯表面的肝素含量:IPDI型聚氨酯和HMDI型聚氨酯表面肝素(PU-PVA-PEO-Hep)接枝量分别达到64.8,51.0mg/m2。②肝素释放速率:浸泡20d后,IPDI型聚氨酯肝素化表面(PU-PVA-PEO-R-NHCO-Hep)的肝素含量从64.8mg/m2下降到51.7mg/m2(脱落20.2%),HMDI型聚氨酯肝素化表面(PU-PVA-PEO-Hep)的肝素含量从51.0mg/m2下降到39.1mg/m2(脱落23.3%)。肝素的释放速率在浸泡7d后达到稳定,约为0.6×10-8g/(m2·min)。③聚氨酯表面接枝肝素后溶血率:溶血率有一定降低(IPDI型从2.40%降低至1.94%、HMDI型从3.20%降低至2.36%),溶血率均小于5%,符合生物医用材料的溶血性要求,其中IPDI型聚氨酯血液相容性好于HMDI型。④血小板黏附情况:表面改性之前,IPDI型聚氨酯表面黏附的血小板数目多于HMDI型。IPDI型聚氨酯抑制血小板形成血栓的能力好于HMDI型。表面接枝肝素后,PU-PVA-PEO-Hep的血液相容性优于PU-PVA-Hep和PU-PEO-Hep。结论:表面共价键合法接枝肝素的脂肪族聚氨酯有良好的血液相容性,且肝素释放速率慢,基本满足人工心脏瓣膜材料的要求。