Spatial analysis for epidemiology

Remote sensing, geographical information systems (GIS) and spatial analysis provide important tools that are as yet under-exploited in the fight against disease. As the use of such tools becomes more accepted and prevalent in epidemiological studies, so our understanding of the mechanisms of disease systems has the potential to increase. This paper introduces a range of techniques used in remote sensing, GIS and spatial analysis that are relevant to epidemiology. Possible future directions for the application of remote sensing, GIS and spatial analysis are also suggested.     

The effect of trigeminal nociceptive stimulation on blink reflexes and pain evoked by stimulation of the supraorbital nerve

The aim of this study was to investigate the effect of painful conditioning stimuli on pain and blink reflexes to supraorbital nerve stimulation. Electromyograph activity was recorded bilaterally from the orbicularis oculi muscles in 13 normal participants in response to low (2.3 mA) and high-intensity (18.6 mA) electrical stimulation of the left supraorbital nerve before, during and after the application of ice to the left or right temple or immersion of the left hand in ice-water for 60 s. The pain evoked by the high-intensity electrical stimulus was greater during painful conditioning stimulation of the ipsilateral temple than during the recovery period afterwards, and was greater than during painful conditioning stimulation of the contralateral temple. These findings imply that spatial summation of nociceptive signals across different divisions of the trigeminal nerve can heighten pain. However, painful conditioning stimulation, particularly to the right temple, strongly suppressed the R2 component of the blink reflex to the low-intensity stimulus, and also suppressed R2 to the high-intensity stimulus. Thus, an inhibitory influence (e.g. diffuse noxious inhibitory controls) appeared to mask ipsilateral segmental facilitation of R2 during ice-induced headache. This finding contrasts with recent electrophysiological evidence of trigeminal sensitization in migraine.     

Pedigree disequilibrium tests for multilocus haplotypes

Association tests of multilocus haplotypes are of interest both in linkage disequilibrium mapping and in candidate gene studies. For case-parent trios, I discuss the extension of existing multilocus methods to include ambiguous haplotypes in tests of models which distinguish between the cis and trans phase. A likelihood-ratio test is proposed, using the expectation-maximization (E-M) algorithm to account for haplotype ambiguities. Assumptions about the population structure are required, but realistic situations, including population stratification, which violate the assumptions lead to conservative tests. I describe a permutation procedure for the null hypothesis of interest, which controls for violation of the assumptions. For general pedigrees, I describe extensions of the pedigree disequilibrium test to include uncertain haplotypes. The summary statistics are replaced by their expected values over prior distributions of haplotype frequencies. If prior distributions are not available, a valid test is possible by using the E-M algorithm to estimate the null distribution of haplotype frequencies. Similar methods are available for quantitative traits. Exact permutation tests are difficult to construct in small samples, but an approximate procedure is appropriate in large samples, and can be used to account for dependencies between tests of multiple haplotypes and loci.     

Depression in stroke patients 7 years following stroke

OBJECTIVE: To study the frequency of depression in stroke patients many years following stroke, most previous studies having concentrated on the first few years. METHOD: Participants of a previous study of post-stroke depression (99 stroke patients and 28 control subjects) were re-examined 7 years later. Depression was diagnosed using research diagnostic criteria. The test battery comprised the Mini Mental State Examination, the Raven Matrices A+B and Word Pair Learning. Subjective experience of changes in memory, concentration, mood, irritability and fatigue during the 7-year period was also examined. RESULTS: Twenty per cent of the stroke patients fulfilled the criteria for major or minor depression compared with 11% of the control subjects. No differences in cognitive function were found between depressed and non-depressed stroke patients. The stroke patients reported experiencing more lability of mood and irritability during the 7-year period following stroke than the control subjects. Depressed stroke patients experienced more impairment of concentration and memory function than non-depressed stroke patients. CONCLUSION: Affective symptoms are common among stroke patients 7 years following stroke.     

从颅脑损伤论“脑主神明”

中医学认为“心主神明”。随着现代医学的传入和影响,“脑主神明”之说日盛。然观近年“心主神明”和“脑主神明”之争,多停留在引经据典和考证推理之上,从临床实践来论证的则少之又少。作者不揣愚浅,总结颅脑损伤之临床所见以论证“脑主神明”之说。     

卫星遥感影像中草地信息自动提取方法的研究

采用遥感图像处理ERDAS IMAGINE软件和ETM资料,进行了乌恰县草地信息自动提取技术研究.结果证明,选择7-8月时相,ETM432和543波段合成,经几何校正和增强处理,通过交互的非监督分类提取草地信息,结合非遥感资料辅助以及专家知识参与可以获得比较满意的结果.     

一种组合式远程康复训练机器人的研制：适用性及其安全性

背景：国内对康复机器人的研究起步比较晚,辅助型康复机器人的研究相对较多,而康复训练机器人的研究相对较少,医工跨学科的结合有待加强,国内的康复器械远远不能满足市场对智能化、人机工程化的康复机器人的需求。 目的：针对国内康复专家少而患者较多这一问题,将遥操作机器人技术与康复医疗器械相结合,以期研制一种基于力反馈的组合式远程康复训练机器人系统。 方法：充分考虑到患者的安全性,采用磁流变阻尼器加上直流电机的模式,设计了一种组合式机械臂,将遥操作机器人技术应用于肢体残障者的康复训练,使患者可以根据康复治疗师的远程设定进行康复锻炼,并将虚拟现实技术与康复训练相结合,把枯燥的康复训练变成轻松有趣的游戏。 结果及结论：该系统的服务对象是上肢有运动障碍的患者,通过对机械臂的拆卸和组合,可给患者提供康复需要的不同训练模式和治疗方案;运用计算机网络技术可使患者根据康复医师的远程设定进行康复训练;身临其境的虚拟现实技术显著提高了康复训练的积极性与效果。实验结果表明,所研制的远程康复训练机器人系统具有良好的适用性和安全性。     

A critical commentary and updating of the guinea pig maximization test

The guinea pig maximization test (GPMT) of Magnusson and Kligman was published in 1969. Since then, a vast body of practical experience with the test has been accumulated. New information requires that certain aspects of the procedure be reevaluated, especially with regard to the interpretation of challenge results. In particular, awareness of the phenomenon of hyperirritable skin (the 'angry back' phenomenon) suggests that presently used controls are not always adequate and may overstate allergenicity owing to false-positive reactions. The control group should be exposed to a chemical insult at induction which provokes an inflammatory reaction comparable to the test substance. We present strategies to distinguish irritant from allergic responses. Allergic reactions should persist on rechallenge weeks later, while nonspecific irritant reactions generally fade and are irreproducible in particular animals. Finally, when a chemical is identified as a contact sensitizer of risk is necessary to estimate the relevance of the test result to usage in the real world.     

HLA haplotype sharing in rheumatoid arthritis sibships: Risk estimates subdivided by proband genotype

There is a well-known association between rheumatoid arthritis (RA) and HLA-DR4. Recent research has indicated that both DR4 haplotypes are important in disease predisposition (favoring a recessive mode of inheritance). Others have suggested that certain combinations of genotypes, in particular Dw4/Dw14 heterozygotes, may be more important than others. We examined the mode of inheritance of RA using data from the Arthritis and Rheumatism Council's national repository of family material [Worthington et al. (1994) Br J Rheumatol 33:970–976]. There were 85 affected sibships consisting of 77 sib pairs, 6 trios, 1 quintuplet, and 1 sextuplet. The affected sibs shared two, one, and zero parental HLA haplotypes in a ratio of 0.42:0.43:0.15, which was significantly different from random expectations (P = 0.00009). Risk estimates for RA to sibs were calculated based on an overall sibling recurrence risk of 3.9%. Risks for those sharing two, one, and zero parental HLA haplotypes were 6.5% [95% confidence interval (CI) = 5.1–7.9%], 3.3% (95% CI = 2.6–4.0%), and 2.5% (95% CI = 1.5–3.5%), respectively. We also examined the risk of RA based on the DRβ1 genotype status of sib and proband. After excluding genotypic combinations with small numbers, the highest genotype-specific risks were seen for sibs sharing two haplotypes with either a DRβ1*0401/DRβ1*0404 (12.5%, 95% CI = 6.9–15.2%) or a DRβ1*0401/DRβ1*0408 (11.1%, 95% CI = 4.5–15.1%) proband. An independent assessment based on the AGFAP methodology confirmed the increase in risk for these genotypes, in particular for DRβ1*0401/DRβ1*0408. The excess being due to *0401/*0408 rather than to *0401/*0404 may explain why the Dw4/Dw14 effect is not always observed. Genet. Epidemiol. 15:403–418,1998. © 1998 Wiley-Liss, Inc.     

Peer,professional, and public: An analysis of the drugs policy advocacy community in Europe

BackgroundIn recent decades a range of advocacy organisations have emerged on the drugs policy landscape seeking to shape the development of policy at national and international levels. This development has been facilitated by the expansion of ‘democratic spaces’ for civil society participation in governance fora at national and supranational level. However, little is known about these policy actors – their aims, scope, organisational structure, or the purpose of their engagement.MethodsDrug policy advocacy organisations were defined as organisations with a clearly stated aim to influence policy and which were based in Europe. Data on these organisations was collected through a systematic tri-lingual (English, French and Spanish) Internet search, supplemented by information provided by national agencies in the 28 EU member states, Norway and Turkey. In order to differentiate between the diverse range of activities, strategies and standpoints of these groups, information from the websites was used to categorise the organisations by their scope of operation, advocacy tools and policy constituencies; and by three key typologies – the type of advocacy they engaged in, their organisational type, and their advocacy objectives and orientation.ResultsThe study identified over two hundred EU-based advocacy organisations (N = 218) which included civil society associations, NGOs, and large-scale alliances and coalitions, operating at local, national and European levels. Three forms of advocacy emerged from the data analysis – peer, professional and public policy. These groups focused their campaigns on practice development (harm reduction or abstinence) and legislative reform (reducing or strengthening drug controls).ConclusionThe findings from this study provide a nuanced profile of civil society advocacy as a policy community in the drugs field; their legitimacy to represent cases, causes, social values and ideals; and their focus on both insider and outsider strategies to achieve their goals. The level of convergence and divergence in Europe in relation to policy positions on service provision ethos and drug control regulation is indicated.