超级刀片计算机上任务并行生物计算程序的效率优化

在后基因组时代，基因结构、功能及其与疾病的关系已成为生物医学的研究热点。在各种实验技术飞速发展的促进下，高复杂度、多元化、海量的生物数据正以指数级的速度不断增长，关于这些数据的存储、计算、分析等已成为严峻挑战。以超级计算机为平台的高性能计算是解决此类难题的有效方法之一。根据对本院超级刀片计算机的使用情况，本文从数据存储、通讯优化、计算效率、资源分配等角度，分析和总结提高任务并行的生物计算程序效率的技术策略，并进一步展望其在生物医学中的应用前景。这些技术策略对于使用同类高性能计算机具有重要的参考价值。     

Quantitative analysis of left ventricular performance from sequences of cardiac magnetic resonance imaging using active mesh model

In this study, the local and global left ventricular function are estimated by fitting three-dimensional active mesh model (3D-AMM) to the initial sparse displacement which is measured from an establishing point correspondence procedure. To evaluate the performance of the algorithm, eight image sequences were used and the results were compared with those reported by other researchers. The findings were consistent with previously published values and the clinical evidence as well. The results demonstrated the superiority of the novel strategy with respect to formerly presented algorithm reported by author et al. Furthermore, the results are comparable to the current state-of-the-art methods.     

Bilateral phacomorphic angle-closure glaucoma in a highly myopic patient secondary to isolated spherophakia

BackgroundAngle closure most commonly occurs in older hyperopic patients as a result of primary relative pupil block. Less frequently, angle closure occurs in highly myopic patients with conditions other than primary relative pupil block. This report presents the diagnosis, pathophysiologic mechanism, and management of a patient with both high myopia and bilateral advanced phacomorphic angle-closure glaucoma caused by isolated spherophakia.CaseA 40-year-old asymptomatic man with very high myopic astigmatism presented with chronic angle closure and an intraocular pressure of 42 mmHg in both eyes. Additionally there was a nonmyopic fundus and 24-mm axial length, with a clear crystalline lens protruding through the pupillary plane in each eye, confirmed by B-scan ultrasonography. Gonioscopy and A-scan and B-scan ultrasonography identified the pathogenesis of intraocular pressure elevation, angle closure, and high myopia to be lenticular in origin. Initial medical therapy and subsequent laser iridotomy relieved the pupil block angle closure and successfully lowered intraocular pressure.ConclusionAngle closure can occur in highly myopic eyes. Careful gonioscopy and ultrasonography can lead to the correct diagnosis and tailored management for these eyes. Phacomorphic angle-closure glaucoma from spherophakia is associated with Weill-Marchesani syndrome as well as a few other uncommon syndromes. Isolated pseudophakia is a rarely reported cause of phacomorphic angle closure.     

Benchmark dose approaches in chemical health risk assessment in relation to number and distress of laboratory animals

Use of benchmark dose (BMD) approaches is expected to increase substantially, with growing awareness among researchers and inclusion in regulatory testing guidance documents such as REACH. The BMD approach has clear advantages over the No-Observed-Adverse-Effect-Level (NOAEL) approach in defining toxicological thresholds, risk levels, and points of departure as the basis for setting guidance and limit values. Several aspects of the BMD may increase the use of laboratory animals; the optimal number of dose groups for BMD calculation is between five and ten, rather than the current standard of four; also, experiments with more animals will result in narrow confidence intervals. However, this paper presents several counterarguments suggesting that design of experiments suited for BMD analyses might be used to decrease the distress and use of laboratory animals. If experiments are performed with unequal group size, with fewer animals in the high response dose groups and more animals close to toxicological threshold, the aggregated distress might be reduced. In addition, there is a need to evaluate how the total number of animals affects the quality of BMD (e.g. in terms of confidence intervals). Development of strategies for optimal design of experiments requires tools which evaluate experimental designs from an ethical perspective; a concept of distress-adjusted number of animals is suggested.     

Proportion of deproteinized bovine bone and autogenous bone affects bone formation in the treatment of calvarial defects in rabbits

This study assessed new bone formation generated using three different proportions of autogenous bone (AB) and deproteinized bovine bone (DBB). Thirty bicortical skull defects were prepared in 15 rabbits, divided into 3 groups: Group 1, critical size defect (CSD) versus AB as controls; Group 2, DBB versus a composite of AB and DBB using a proportion of 1:1; and Group 3, a composite of AB and DBB using a proportion of 1:2 versus a proportion of 1:4. After 8 weeks, radiographic evaluation was assessed using densitometry and new bone formation by histomorphometry. The mean optical density of the CSD (0.108 ± 0.238) and AB (0.352 ± 0.161) groups differed significantly from the DBB group (1.044 ± 0.093) and the groups using a proportion of 1:1 (0.905 ± 0.078), 1:2 (0.865 ± 0.294) and 1:4 (0.867 ± 0.304). Histomorphometry revealed a higher percentage of new bone in the AB group (30.223 ± 16.722) than in the groups using proportions of 1:2 (22.639 ± 5.659), 1:1 (20.929 ± 6.169), 1:4 (9.621 ± 2.400), DBB (14.441 ± 2.742) and CSD (10.645 ± 8.868), respectively. The 1:2 group had significantly higher bone content than the 1:4 group. The proportions of 1:1 and 1:2 resulted in greater bone formation than the proportion of 1:4, DBB and CSD.     

Silodosin: A selective α1A-adrenergic receptor antagonist for the treatment of benign prostatic hyperplasia

Background: Silodosin is a new α₁-adrenergic receptor antagonist that is selective for the α_1A-adrenergic receptor. It was approved by the US Food and Drug Administration (FDA) in 2008 for the treatment of lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH).Objective: This article reviews the pharmacology, pharmacokinetics, clinical efficacy, adverse effects, drug interactions, and dosage and administration of silodosin in adult male patients with BPH.Methods: A search of MEDLINE (1950–October 8, 2009), International Pharmaceutical Abstracts (1970–October 8, 2009), and the Iowa Drug Information Service database (1966–October 8, 2009) was conducted using the terms silodosin, KMD-3213, benign prostatic hyperplasia, and α₁-adrenergic receptor antagonist. Reports of research and review articles published in English were identified and evaluated, and the bibliographies of these articles were reviewed for additional relevant publications. A search of the FDA Web site was performed, and abstracts and posters presented at scientific meetings of the American Urological Association were reviewed.Results: By antagonizing α_1A-adrenergic receptors in the prostate and urethra, silodosin causes smooth muscle relaxation in the LUT. Silodosin has greater affinity for the α_1A-adrenergic receptor than for the α_1B-adrenergic receptor (by a factor of 583), minimizing the propensity for blood pressure-related adverse effects mediated by α_1B blockade. In 3 controlled clinical studies in patients with BPH-related LUTS (1 published; 2 presented in the prescribing information and published in a pooled analysis), patients receiving silodosin at a total daily dose of 8 mg had significant improvements in the International Prostate Symptom Score (IPSS) and maximum urinary flow rate (Q_max) compared with those receiving placebo (both, P < 0.05). The most commonly reported adverse effect was abnormal or retrograde ejaculation (>22%), and the incidence of orthostatic hypotension was low (<3%).Conclusions: In the small number of clinical trials reviewed, silodosin was associated with significant reductions in IPSS and Q_max compared with placebo. To determine whether silodosin's selectivity for the α_1A-adrenergic receptor translates into a clinical advantage relative to other available agents, long-term studies evaluating the comparative efficacy and tolerability of silodosin and other α₁-blockers (specifically tamsulosin) are necessary.