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101.
102.
Suitable measures of health and morbidity are less readily available for children than they are for adults. We present a measure, which is used to describe the impact of impairment and disability on the lives of children with cerebral palsy and their families. The development of this measure involved data collected from 691 children with cerebral palsy contained within the North-East England Cerebral Palsy Register and born between 1960 and 1985. Uniquely, multidimensional scaling techniques were used to derive dimensions analogous with those described in the International Classification of Impairments, Disabilities, and Handicaps. We present the analyses undertaken to test the properties of the tool, which show that it is a reliable and valid measure of the disadvantages experienced by children with cerebral palsy. 相似文献
103.
When viewing a moving object, details may appear blurred if the object's motion is not compensated for by the eyes. Smooth pursuit is a voluntary eye movement that is used to stabilize a moving object. Most studies of smooth pursuit have used small, foveal targets as stimuli (e.g. Lisberger SG and Westbrook LE. J Neurosci 1985;5:1662-1673.). However, in the laboratory, smooth pursuit is poorer when a small object is tracked across a background, presumably due to a conflict between the primitive optokinetic reflex and smooth pursuit. Functionally, this could occur if the motion signal arising from the target and its surroundings were averaged, resulting in a smaller net motion signal. We asked if the smooth pursuit system could spatially summate coherent motion, i.e. if its response would improve when motion in the peripheral retina was in the same direction as motion in the fovea. Observers tracked random-dot cinematograms (RDC) which were devoid of consistent position cues to isolate the motion response. Either the height or the density of the display was systematically varied. Eye speed at the end of the open-loop period was greater for cinematograms than for a single spot. In addition, eye acceleration increased and latency decreased as the size of the aperture increased. Changes in the density produced similar but smaller effects on both acceleration and latency. The improved pursuit for larger motion stimuli suggests that neuronal mechanisms subserving smooth pursuit spatially average motion information to obtain a stronger motion signal. 相似文献
104.
SN Chen 《Canadian Metallurgical Quarterly》1996,15(2):517-521
Shrimp culture is an attractive sector of aquaculture business, in view of the high profits and quick turnover. The vast majority of cultured shrimp production occurs in Asian countries. The author details the levels of production, consumption and trade of cultured shrimps since 1991 in and between the major producing countries. A decline in production has been registered in some countries in recent years, due to mass mortality caused by a number of diseases (particularly 'white spot' disease). Efforts to overcome these problems have met with only partial success. 相似文献
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WE Karnes R Shattuck-Brandt LJ Burgart RN DuBois DJ Tester JM Cunningham CY Kim SK McDonnell DJ Schaid SN Thibodeau 《Canadian Metallurgical Quarterly》1998,58(23):5473-5477
Most colorectal adenomas and carcinomas arise in the setting of chromosomal instability characterized by progressive loss of heterozygosity. In contrast, approximately 15-20% of colorectal neoplasms arise through a distinct genetic pathway characterized by microsatellite instability (MSI) associated with frequent loss of expression of one of the DNA mismatch repair enzymes, most often hMLH1 or hMSH2. These distinct genetic pathways are reflected by differences in tumor histopathology, distribution in the colon, prognosis, and dwell time required for progression from adenoma to carcinoma. To determine whether these two groups of tumors differ in their expression of cyclooxygenase-2 (COX-2), a putative chemopreventative target, immunostaining for this protein was performed in colorectal cancers categorized by the presence (n = 41) and absence (n = 66) of defective mismatch repair. Defective mismatch repair was defined by the presence of tumor microsatellite instability (MSI-H, > or =40% of markers demonstrating instability) and by the absence of protein expression for either hMLH1 or hMSH2. Overall, our results showed that low or absent COX-2 staining was significantly more common among tumors with defective mismatch repair (P = 0.001). Other features predictive of low COX-2 staining included marked tumor infiltrating lymphocytosis, and solid/cribiform or signet ring histological patterns. These observations indicate that colorectal cancers with molecular and phenotypic characteristics of defective DNA mismatch repair express lower levels of COX-2. The clinical implications of this biological distinction remain unknown but should be considered when assessing the efficacy of COX-2 inhibitors for chemoprevention in patients whose tumors may arise in the setting of defective DNA mismatch repair. 相似文献
108.
Increasingly, epidemiologists are faced with the need to evaluate the impact of an intervention that is delivered at the level of a community or cluster of individuals, rather than at the individual level. This has profound implications for the design and interpretation of a study to evaluate its impact. We start by discussing the issues arising in the extension of the randomized double-blind controlled trial methodology to the evaluation of interventions delivered to clusters of individuals, or to whole communities, where the unit of randomization is a cluster of individuals rather than an individual. We then consider alternative approaches to design, discuss their relative strengths and weaknesses and present a framework of design options. Finally we propose a pragmatic approach to evaluation design in this setting. We believe that the answer lies in the judicious selection of different design elements, combined in such a way that when the evidence from each is presented together, a clear picture of the impact of the intervention emerges. We illustrate this using an example from the recent literature. 相似文献
109.
Aggressiveness, hypoalgesia and high blood pressure in mice lacking the adenosine A2a receptor 总被引:1,自引:0,他引:1
C Ledent JM Vaugeois SN Schiffmann T Pedrazzini M El Yacoubi JJ Vanderhaeghen J Costentin JK Heath G Vassart M Parmentier 《Canadian Metallurgical Quarterly》1997,388(6643):674-678
Adenosine is released from metabolically active cells by facilitated diffusion, and is generated extracellularly by degradation of released ATP. It is a potent biological mediator that modulates the activity of numerous cell types, including various neuronal populations, platelets, neutrophils and mast cells, and smooth muscle cells in bronchi and vasculature. Most of these effects help to protect cells and tissues during stress conditions such as ischaemia. Adenosine mediates its effects through four receptor subtypes: the A1, A2a, A2b and A3 receptors. The A2a receptor (A2aR) is abundant in basal ganglia, vasculature and platelets, and stimulates adenylyl cyclase. It is a major target of caffeine, the most widely used psychoactive drug. Here we investigate the role of the A2a receptor by disrupting the gene in mice. We found that A2aR-knockout (A2aR-/-) mice were viable and bred normally. Their exploratory activity was reduced, whereas caffeine, which normally stimulates exploratory behaviour, became a depressant of exploratory activity. Knockout animals scored higher in anxiety tests, and male mice were much more aggressive towards intruders. The response of A2aR-/- mice to acute pain stimuli was slower. Blood pressure and heart rate were increased, as well as platelet aggregation. The specific A2a agonist CGS 21680 lost its biological activity in all systems tested. 相似文献
110.
The impact of a required college health and physical education course on the health status of alumni
SN Pearman RF Valois RG Sargent RP Saunders JW Drane CA Macera 《Canadian Metallurgical Quarterly》1997,46(2):77-85
Social interactions between mothers that were holding their infants and other group members were studied in a wild group of moor macaques (Macaca maurus). Affiliative approaches to infants (AAI) by group members that were accompanied with particular behaviours, such as mouthing and touching or affiliative grunts, were observed frequently. Females approached mothers with infants more frequently than did males in all age classes. Female reproductive status, parity and dominance relationships between interactants had little effect on the frequency of approaches. Mothers received more grooming and performed less grooming when they were holding their infants than when they were not. A high level of social tolerance in macaque species with relaxed dominance styles might allow the free expression of AAI. Dominance styles among females and AAI could be linked via a positive feedback relationship since AAI might play a role in relaxing the dominance style among females. 相似文献