广州市大学生尝试自杀现况及其影响因素分析

目的了解广州市大学生尝试自杀现状及其影响因素，为高校健康教育提供理论依据。方法采用整群随机抽样方法，用自编调查表对大学生进行问卷调查，在此基础上结合专题小组讨论的定性研究方法进行分析。结果大学生近1a内尝试自杀报告率为6．0％，不同性别、学校、专业的学生尝试自杀报告率差异无统计学意义（P〉0．05）；城镇学生尝试自杀报告率为6．6％，高于农村学生的4．2％（x^2=4．71，P=0．032）。对自杀行为的态度、朋友和家人有过自杀行为、消极应对、负性生活事件等是尝试自杀的危险因素，获得社会支持是尝试自杀的保护因素。定性访谈发现，学校几乎没有开展过自杀行为的健康教育活动，绝大部分学生对自杀行为持中立态度。结论加强健康教育、消除危险因素、提高保护因素可以最大限度地预防自杀.     

Physical inactivity, excess adiposity and premature mortality

The purpose of this report is to review the evidence that physical inactivity and excess adiposity are related to an increased risk of all‐cause mortality, and to better identify the independent contributions of each to all‐cause mortality rates. A variance‐based method of meta‐analysis was used to summarize the relationships from available studies. The summary relative risk of all‐cause mortality for physical activity from the 55 analyses (31 studies) that included an index of adiposity as a covariate was 0.80 [95% confidence interval (CI) 0.78–0.82], whereas it was 0.82 [95% CI 0.80–0.84] for the 44 analyses (26 studies) that did not include an index of adiposity. Thus, physically active individuals have a lower risk of mortality by comparison to physically inactive peers, independent of level of adiposity. The summary relative risk of all‐cause mortality for an elevated body mass index (BMI) from the 25 analyses (13 studies) that included physical activity as a covariate was 1.23 [95% CI 1.18–1.29], and it was 1.24 [95% CI 1.21–1.28] for the 81 analyses (36 studies) that did not include physical activity as a covariate. Studies that used a measure of adiposity other than the BMI show similar relationships with mortality, and stratified analyses indicate that both physical inactivity and adiposity are important determinants of mortality risk.     

老年人前瞻性记忆损害的研究

目的 了解健康老年人前瞻性记忆改变的情况,初步探讨老年人基于事件的前瞻性记忆(EBPM)和基于时间的前瞻性记忆(TBPM)损害程度的区别.方法 建立前瞻性记忆的神经心理学测验方法,测试教育程度相匹配的40名健康老年人和40名健康成年人的EBPM和TBPM.结果 与成年组[EBPM(6.25±1.60)分;TBPM(5.38±0.87)分]相比,老年组的EBPM[(2.50±0.85)分和TBPM(4.93±1.07)分]均较成年组差(P＜0.01,P＜0.05),而EBPM损伤指数的差异亦有统计学意义(P＜0.01).老年组前瞻性记忆的EBPM和TBPM存在双分离.结论 老年人存在前瞻性记忆的损害,EBPM损害较TBPM损害更为显著.EBPM和TBPM的双分离表明其可能有不同的神经机制,推测额叶可能特异性地参与了EBPM.     

Signal-to-noise ratio effects in quantitative cerebral perfusion using dynamic susceptibility contrast agents.

Theoretical and simulation evidence is presented in support of the idea that the optimal manner of determining blood flow from MR perfusion studies is not necessarily obtained by setting experimental conditions to maximize either the arterial input or the measured tissue concentration level for a particular echo time (TE). The noise power in the contrast concentration curve is associated with its peak because of the nonlinear relationship between the contrast concentration and MR signal intensity curves. The optimum signal-to-noise ratio (SNR), SNR(C), for a particular contrast concentration curve can be obtained when the experimental concentration level and TE are adjusted to produce an MR intensity curve whose signal loss is 63% of the precontrast MR signal intensity. It is demonstrated that the stability of the singular valued decomposition (SVD) deconvolution approach to determine blood flow parameters is increased when the tissue curve maximum signal loss is in the range of 40-80%. The accuracy and stability of the SVD-determined blood flow parameters are affected by deviations from these optimum conditions in a manner that depends on the mean transit time (MTT) associated with the residue function. It is recommended that the experimental TE value be set so that neither the tissue nor the arterial curves are placed a region of rapidly deteriorating SNR(C).     

Designed polyanionic coiled-coil proteins: acceleration of heparin cofactor II inhibition of thrombin

Novel polyanionic proteins were designed to increase the rate of heparin cofactor II (HC) inhibition of α-thrombin, an essential protease in the coagulation cascade. Two α-helical coiled-coil proteins, a 62-residue dimer containing 8 Glu residues (E8C) and a 104-residue dimer containing 14 Glu residues (E14C), plus two 31-residue control peptides containing 8 Glu residues each (E8A and E8B), were chemically synthesized, structurally characterized and enzymatically assayed. Circular dichroic spectrophotometry indicated that both E8C and E14C formed stable two-chain α-helical coiled coils at pH 7 and 25 °C. The control peptides were only partially α-helical. E14C remained folded at 90 °C but E8C was half unfolded at 49 °C. Coiled-coil proteins E8C and E14C maximally accelerated by 35- and 33-fold, respectively, the rate of HC inhibition of α-thrombin. None of these compounds accelerated antithrombin inhibition of α-thrombin, and neither control peptide accelerated HC inhibition of α-thrombin. Acceleration of the HC inhibition of α-thrombin showed bimodal dependence on the concentration of the polyanionic protein, which is consistent with formation of a HC-coiled-coil-thrombin ternary complex. The results suggest that antithrombotic polyanionic α-helical coiled-coil proteins can be designed and synthesized and that the occurrence of secondary structure can be correlated with biologcal activity. © Munksgaard 1995.     

173例支气管哮喘特异性脱敏治疗的进一步评价

对173例支气管哮喘特异性脱敏治疗的疗效及影响疗效的因素进行了分析。结果表明:显效为30.6%(53/173).有效为56.1%(97/173),无效为13.3%(23/173)。影响疗效的因素与病情的程度有关,而与年龄、病程、皮试阳性反应强弱及脱敏治疗前4个疗程内是否应用曲安缩松等无关。并对特异性脱敏治疗支气管哮喘的优缺点进行讨论。     

原发性闭角型青光眼发病危险因素的病例对照研究

为探讨原发性闭角型青光眼的发病危险因素，对１０３例原发性闭角型青光眼患者和９５例非青光眼对照者进行了回顾性病例对照研究。结果发现原发性闭角型青光眼的主要危险因素有青光眼家族史、脾气暴躁及易激动、近距离用眼职业和高血压病，未发现吸烟、饮酒、糖尿病、近视眼和ＡＢＯ血型与原发性闭角型青光眼的发病有统计学联系。     

准分子激光原位角膜磨镶术治疗近视眼的临床分析

目的:评价准分子激光原位角膜磨镶术(LASIK)治疗轻、中、高度及超高度近视的预测性、稳定性及安全性.方法:使用Technolas 217 C准分子激光治疗仪及Hansatome微型角膜板层刀对4 000只近视及近视散光眼行LASIK手术.根据术前近视程度,将有2年随访结果的1 148只眼分3组:Ⅰ组-1.00～-6.00 D(等值球镜,下同)462眼;Ⅱ组-6.25～-10.00 D 466眼;Ⅲ组-10.25～-15.00 D 220眼.结果:1 148只眼术后2年裸眼视力≥1.0(或≥术前最佳矫正视力)在Ⅰ组为97.8％,Ⅱ组为93.8％,Ⅲ组为90.5％,裸眼视力≥0.5(或比术前最佳矫正视力下降少于等于2行)在Ⅰ组为100％,Ⅱ组为96.4％,Ⅲ组为94.0％;剩余屈光度在Ⅰ组为(-0.24±0.31)D,Ⅱ组为(-0.55±0.63)D,Ⅲ组为(-1.17±0.75)D;无1眼最佳矫正视力下降2行以上.4 000只眼术中游离瓣及不完全瓣、不规则瓣发生率0.13％,上皮植入发生率0.18％,术后眼压轻度升高发生率0.48％,无严重并发症发生.结论:LASIK治疗-15.00 D以下轻、中、高度及超高度近视眼均可获得较好疗效,具有较好的安全性、可预测性及稳定性.     

Eight years'' experience with a structured clinical examination

A structured clinical examination has been an integral component of the final-year examinations conducted by the Departments of Medicine and Surgery at the University of Adelaide for the last 8 years. It has been used as an alternative to the traditional clinical examination. This paper describes the results of ongoing student and examiner surveys carried out to determine their views and satisfaction with this new approach. It also briefly discusses the feasibility of introducing such an examination into a conventional medical school environment. The surveys showed a remarkable level of acceptance and support by both students and examiners. This positive reaction has been maintained over the 8-year period. The main reasons seem to be its perceived relevance and fairness. Students also appear to be directing their learning in a direction thought desirable by teachers. No significant problems have been encountered with the practical implementation of the method.     

Retrograde air insufflation in MRI: A technical note

Retrograde air insufflation was employed to distend the colon and the ileum in 18 patients and five volunteers for magnetic resonance examination. Good and moderate marking of the ileum was obtained in 18 cases. The colon was nearly completely distended in every case. Intraluminal tumor, mural thickening, and extraluminal lesion were outlined by intraluminal air and surrounding air-distended bowel. This study shows that retrograde air insufflation is a useful method to mark the colon and most parts of the ileum.