The application of basic science concepts to clinical problem-solving

This study looks at the relationship between anatomical concepts held by medical students and their clinical application, and develops a testable model of how students use basic science concepts for clinical problem-solving. According to the model, the essential prerequisites to solve a clinical problem using basic science information include the appropriate basic science knowledge, the ability to collect and interpret clinical information, with the key concept being the link that must then be made between clinical data and basic science. A detailed analysis of the individual components of the model should help to clarify and resolve some of the debate about the nature and balance of basic science and clinical education. A neurological diagnostic problem was used to test the assumptions of the model in a group of medical students who had minimal clinical experiences. There was no demonstrable relationship between anatomical knowledge as assessed by conventional tests and the diagnosis. There was a powerful relationship between measures of organization of knowledge and diagnosis, suggesting that the organization and development of concepts is the key to correct diagnosis. The findings have significant implications for assessment purposes and suggest that standard methods as generally practised may not measure the appropriate conceptual development and are not congruent with curricular objectives. Through the examination of its different learning outcome measures, the model may also be used to provide a profile of individual students or classes, which should help teachers and students deal with difficulties that may be experienced in learning to link clinical and basic science concepts.     

Paradigms for mental health nursing: fragmentation or integration?

Debate about the best paradigm for mental health nursing is compounded by threats from mainstreaming and genericism. In nursing education, integrated practice may have been devalued in a matrix of reductionist disciplines. The 'gendered' nature of professional knowledge may create a schismatic and self-defeating attitude in nurses. Conversely, nurses may be exhorted to adopt a 'male' paradigm in order to gain academic credibility, in which the caring dimension may be lost. Other polarities such as ideological distinctions between treatment in hospital and care in the community lead to conceptual confusion. These schisms in care are detrimental to both professionals and users. The writers argue that these tensions may be addressed in an 'androgenous' model which presents a challenge to both value systems, rejects the dominance of schismatic models, and offers the potential for a new professional integrity.     

黄芪总皂甙对在体犬心功能的影响

结扎左冠状动脉前降支中点或最大斜角支根部，造成麻醉犬急性心肌梗塞模型，用ＲＭ一６０００多道记录仪动态监测心功能和心电图，并进行实验性治疗。证实黄芪总皂甙能明显改善心梗大的心肌收缩性能，增加冠脉流量，对心功能有保护作用。     

苯丙胺诱发小鼠激怒反应及其机制

苯丙胺15mg/kg ip能诱发小鼠激怒反应,使小鼠出现攻击和殴斗行为。强安定药、弱安定药和利血平有明显拮抗效果。镇静剂如巴比妥类、抗胆碱药及抗肾上腺素药均无拮抗作用。金刚胺、左旋多巴和阿扑吗啡均能增强苯丙胺的激怒效应。因苯丙胺激怒小鼠的方法简便易行,可作为筛选抗精神病药的动物模型。苯丙胺产生激怒作用的机制与增强多巴胺能神经的功能有关,推测可能是促进边缘系统多巴胺释放的结果。     

颞下颌关节的三维有限元法研究

本研究利用颞下颌关节ＣＴ扫描资料和计算机图像分析处理技术以及三维有限元方法相结合建立了髁状突的三维有限元模型，结果表明，此方法在技术上是可行的并将有助于颞下颌关节的临床和基础研究。     

Mechanisms of proteinuria in nephrotic humans

The glomerular capillary wall imposes a remarkably efficient barrier to the passage of proteins the size of albumin and larger. The development of heavy proteinuria signifies impairment of the function of this barrier. Because endogenous proteins of graded size are heterogeneous with respect to their molecular charge and undergo extensive tubular reabsorption, they are not useful for quantifying the extent of barrier dysfunction. An alternative approach is to determine the fractional clearance of uncharged and non-reabsorbable polymers of graded size. When combined with a hydrodynamic theory of solute transport through a heteroporous membrane, the intrinsic properties of healthy and diseased glomerular capillary walls can be inferred. This approach reveals the nephrotic range proteinuria that attends minimal change nephropathy to be associated with impairment of both the size- and charge-selective properties of glomerular capillary walls.     

5-HT1A receptor agonists: recent developments and controversial issues

During the last decade, serotonin (5-HT)_1A receptors have been a major target for neurobiological research and drug development. 5-HT_1A receptors have been cloned and a variety of selective agonists, such as the aminotetraline 8-OH-DPAT and the pyrimidinylpiperazine ipsapirone, have become available. Demonstrations of apparent intrinsic activity of these ligands at 5-HT_1A receptors, however, depend highly on the particular assay system. This may be due to the possible existence of receptor subtypes and to assay (or brain region)-dependent differences in receptor reserve and the nature of receptor-effector coupling. Nevertheless, the apparent intrinsic activity of 8-OH-DPAT seems to be higher (although possibly not yet maximal) than that of the pyrimidinylpiperazines. In the brain, 5-HT_1A receptors are located presynaptically as somatodendritic receptors on 5-HT neurons and postsynaptically in particular limbic and cortical regions. Although it is generally accepted that presynaptic 5-HT_1A receptors control 5-HT neuronal activity, recent evidence suggests an additional role of postsynaptic 5-HT_1A receptors in cortex as part of a negative feedback loop. Anxiolytic and antidepressive properties of selective 5-HT_1A receptor agonists have now been confirmed by clinical studies. Although it is well established that the latter properties depend on theagonistic activity of these compounds, theoptimal level of intrinsic activity is still a matter of debate and may be dependent on the clinical indication. Such compounds may also have antiaggressive effects, and possibly anticraving effects (manifested by their alcohol intake-reducing effects in dependent animals), but the specificity of these so-called anti-impulsivity effects is still controversial and not yet tested clinically. Anticataleptic, antiemetic and neuroprotective properties have been demonstrated in different species. Behavioral studies on the mechanisms underlying the anxiolytic and antidepressive effects have examined the relative contribution of pre-and postsynaptic 5-HT_1A receptors by means of local cerebral application and lesion techniques. Most evidence points towards a critical involvement of presynaptic receptors in the anxiolytic effects of 5-HT_1A receptor agonists (although a possible contribution of postsynaptic receptors cannot be excluded). With regard to the antidepressive properties, a case can be made for the reverse; i.e., a strong involvement of postsynaptic receptors and a questionable contribution of presynaptic receptors. However, as the therapeutic effects of those 5-HT_1A receptor (partial) agonists which have been tested clinically require repeated administration, attention has been directed increasingly towards chronic studies. These studies have shown that a number of electrophysiological, biochemical, behavioral and endocrinological 5-HT_1A receptor-related events adapt differentially to repeated or sustained administration. Thus, several hypotheses accounting for the delayed onset of action have been advanced. Among these, time-dependent downregulation /desensitization of eitherpre- orpostsynaptic 5-HT_1A receptors, or cortical 5-HT₂ receptors have received much attention. However, these hypotheses have their weaknesses, and it is argued thatfunctional sensitization of particular postsynaptic 5-HT_1A receptor-mediated events remains a valuable alternate hypothesis. Basic research on the role of 5-HT_1A receptors in psychopathology and in the therapeutic effects of clinically effective therapeutics, as well as on the mechanism of action of 5-HT_1A receptor ligands, will enable rational design of ligands with particular profiles of intrinsic activity at different 5-HT_1A receptor populations, and may contribute to a more efficient treatment of a multiplicity of brain disorders.     

Segregation analysis of diastolic blood pressure in a large pedigree

Hypertension, a major risk factor for cardiovascular diseases, is thought to be inherited to some extent. However, the nature of its genetic component remains unresolved. In the present study, data from a single large kindred (the HGAR1 pedigree) were used to search for evidence of single gene and multifactorial effects on diastolic blood pressure. Commingling analyses found that a mixture of three distributions fit the data significantly better than a single normal distribution, suggesting a major effect influencing diastolic blood pressure levels. However, segregation analysis, using regressive models, indicated that the transmission probabilities were not consistent with Mendelian expectations. There was no evidence of either major gene or polygenic effects on diastolic blood pressure levels in this family. © 1993 Wiley-Liss, Inc.     

复方丹参滴丸对急慢性高粘滞血症模型血管内皮细胞分泌功能的影响

目的：观察复方丹参滴丸对高粘滞血症血管内皮分泌功能的影响，探索其作用机制。方法：复合因素(高分子右旋糖酐、肾上腺素、牛血清白蛋白)、长时间(112天)造成高粘滞血症慢性模型；一次性静脉注射高分子右旋糖酐。皮下注射(sc)肾上腺素造成急性高粘滞血症模型，分别用复方丹参滴丸进行治疗，观察血管肉皮细胞分泌功能的变化。结果：慢性高粘滞血症模型血浆血栓素B2(TXB2)和内皮素(ET)浓度非常显升高，而6-酮-前列腺素F1x(6-酮)浓度非常显降低；急性高粘滞血症模型血管内皮分泌功能无显变化；长期使用复方丹参滴丸能调整、改善血管内皮分泌功能的异常状态；复方丹参滴丸改善血管内皮分泌功能的即时效应不显。