Three-dimensional reconstruction of median eminence microvascular modules

To test the hypothesis that the median eminence microvasculature has a direct regulatory role in the hormonal communication between the brain and the pituitary gland, it is necessary to determine whether the physical means for such control (e.g. smooth musele sphineters strategically located in the capillary plexus) actually exists. Our approach is to search for such structures in transmission electron micrographs of thin serial sections of the median eminence. The complexity of these images and the anticipated need to include large numbers of them in the study led us to consider computer reconstruction for this problem. We report here the successful three-dimensional reconstruction of capillary modules using digital image processing techniques for capillary feature detection extraction, for construction of montages (mosaies) of overlapping images of the same section, and for automatic image registration by two independent methods without the use of fiducial marks. These tasks have been performed manually in nearly all the published neurobiological reconstructions: here they are performed by programs using only the mathematical properties of the images. Methods like those deseribed here provide the only practical means for executing large scale reconstructions and gaining significant new information about the regulation of blood flow in this region of the brain.     

The oral glucose tolerance test: An objective method of interpretation

Summary Oral glucose tolerance test results from a positively-skewed, unimodal distribution were analyzed in such a way as to uncover a natural division within the set of results for each time point. The division in results was obtained from a break in the curve formed when plasma glucose concentration was plottedvs the percentile of the population described by those concentrations. The percentile at which the break occurs separated normal from abnormal glucose concentrations objectively. Previously natural divisions between normal and abnormal glucose concentrations had been found only in bimodal distributions from atypical populations such as the Pima Indians and Nauruans of Micronesia. The glucose concentrations at which separations in our unimodal distribution occur compare well with the available data from the atypical populations. According to one measure of reliability, the 3-h time point was more effective than the more commonly utilized 2-h point in distinguishing normal from abnormal plasma glucose concentration.     

Selective destruction of the outer hair cells in the chinchilla

In the study of cochlear function an animal model in which apical outer hair cells could be destroyed with retention of inner hair cells would be valuable. Our object was to attempt to reproduce a reported method in a scientific manner. Behavioural response thresholds to pure tones were recorded in 7 monaural chinchillas. In 5, Kanamycin was administered in ototoxic dosage until the thresholds deteriorated. The other 2 served as controls. Cochlear histology was assessed from embedded surface preparations. In only one of the 5 animals was the aim achieved. In this animal outer hair cells were absent virtually throughout the cochlea and inner hair cell retention was basal. The thresholds were elevated on average 40 dB throughout the frequency range. This is in keeping with current concepts of cochlear function.     

A hearing survey in diabetes mellitus

A sample of 50 diabetics was compared with a control group matched for age and sex. Twenty-two of the diabetics were insulin-dependent. Subjects and controls were examined otologically and then tested audiometrically using pure tone audiometry, speech audiometry and tone decay after the method of Owens. No significant difference was found between the two groups on pure tone audiometry and speech testing showed all diabetics and controls to be normal. A statistically significant incidence of type-2 tone decay was found in the overall group of diabetics at 2000 Hz. This may reflect early presbycusis.     

试论医疗机构管理体制改革的目标

该文从办医格局、管理模式、产权结构、管理机制四个方面阐述了医疗机构管理体制改革的目标:(1)形成"政府举办医院(公立医院)"、"民办非营利性医院"和"民办营利性医院"三种格局;(2)构建医疗机构自主经营、自负盈亏的管理模式;(3)明晰医院的产权结构,塑造医院成为权责明确的法人实体;(4)依靠内涵建设和技术创新改善医院管理机制,提高医院的经营活力.     

随身听装置对青年人听力的影响

目的　探讨使用随身听装置对青年人听力的影响及其早期监测手段。方法　对 30名 (6 0耳 )耳科正常青年人 (对照组 )及 12 0名 (2 4 0耳 )“随身听”使用者 (观察组 )进行常频听阈测试 (0 .5～ 8kHz)和扩展高频听阈测试 (10～ 2 0kHz) ,并对其结果进行统计分析。结果　观察组的扩展高频纯音听阈和常频纯音听阈与对照组相比明显升高 (P <0 .0 5 ) ,且随着随身听使用时间的延长 (P <0 .0 5 ) ,有更多的频率点的听阈高于对照组 ;观察组的扩展高频听阈检出率明显低于对照组 ;观察组中常频听阈正常者和常频听阈异常者其扩展高频听阈均高于对照组 (P <0 .0 5 )。结论　“随身听”的使用可以对正常青年人的听力造成危害 ,扩展高频听阈测试可望成为对噪声造成的早期听力损害的一种敏感监测方法。     

Exploring Associations between Physical Activity and Perceived and Objective Measures of the Built Environment

The built environment may be responsible for making nonmotorized transportation inconvenient, resulting in declines in physical activity. However, few studies have assessed both the perceived and objectively measured environment in association with physical activity outcomes. The purpose of this study was to describe the associations between perceptions and objective measures of the built environment and their associations with leisure, walking, and transportation activity. Perception of the environment was assessed from responses to 1,270 telephone surveys conducted in Forsyth County, NC and Jackson, MS from January to July 2003. Participants were asked if high-speed cars, heavy traffic, and lack of crosswalks or sidewalks were problems in their neighborhood or barriers to physical activity. They were also asked if there are places to walk to instead of driving in their neighborhood. Speed, volume, and street connectivity were assessed using Geographic Information Systems (GIS) for both study areas. Locations of crashes were measured using GIS for the NC study area as well. Objective and perceived measures of the built environment were in poor agreement as calculated by kappa coefficients. Few associations were found between any of the physical activity outcomes and perception of speed, volume, or presence of sidewalks as problems in the neighborhood or as barriers to physical activity in regression analyses. Associations between perceptions of having places to walk to and presence of crosswalks differed between study sites. Several associations were found between objective measures of traffic volume, traffic speed, and crashes with leisure, walking, and transportation activity in Forsyth County, NC; however, in Jackson, MS, only traffic volume was associated with any of the physical activity outcomes. When both objective and perceived measures of the built environment were combined into the same model, we observed independent associations with physical activity; thus, we feel that evaluating both objective and perceived measures of the built environment may be necessary when examining the relationship between the built environment and physical activity. McGinn is with the Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY 10461, USA; Evenson and Huston are with the Department of Epidemiology, University of North Carolina, Chapel Hill, NC, USA; Herring is with the Department of Biostatistics, University of North Carolina, Chapel Hill, NC, USA; Rodriguez is with the Department of City and Regional Planning, University of North Carolina, Chapel Hill, NC, USA.     

Assessment of clinical competence of undergraduate medical students

The assessment is a key determinant of learning by the students. Validity, reliability, objectivity and practicability are the fundamental attributes of assessment. It is important to understand how a given tool of assessment fares on these criteria. The conventional practical clinical examination consisting of “long”/“short” cases lacks objectivity and reliability. It also has a limited validity because sufficient sampling is not possible. Objective Structured Clinical Examination (OSCE), on the other hand, is a comprehensive, reliable and objective test, but does not take a holistic view of the patient. Viva-voce often revolves around theory and is highly subjective. Since no single tool of assessment of clinical competence is ideal, a combination of “long”/“short” case (s) with OSCE is suggested as a more rational examination.     

Control of faecal incontinence using the Malone antegrade continence enema procedure: a critical appraisal

Intractable faecal incontinence remains a major clinical challenge. Children with this problem have been treated using the Malone antegrade continence enema procedure. The first ten consecutive cases carried out in this centre have been prospectively studied and objectively assessed. The children were reviewed for a period of up to 18 months. The technical success of the operation and the improvement in quality of life were evaluated using two separate scoring systems. Nine out of ten patients gained maximum or near-maximum marks in both assessments. Complications were rare, and the procedure can be regarded as a successful treatment of intractable faecal incontinence in children.     

The otological profile of a cohort of Dutch 7.5–8-year-olds

The otological characteristics of a birth cohort of 7.5–8-year-old Dutch children are reported. Questionnaire information was available for 1004 children, while otomicroscopic, tympanometric and pure-tone audiometric data were available for 946 children. Twenty-nine per cent of the children had been treated surgically for various ENT diseases. Fifty-five per cent of the children had normal tympanic membranes, 19% mild abnormalities, and 26% moderate to severe abnormalities. At this age the prevalence of bilateral otitis media with effusion (OME), as shown by a type B tympanogram was 2.5%, while that of unilateral OME was 7%. A pure-tone average hearing level of ≥ 15 dB in the better-hearing ear was found in 4% of the children. The presence of OME was associated with a mean hearing loss of 20 dB. This study shows that structural and functional middle-ear abnormalities are highly prevalent in Dutch school children.