De-coupling of cognitive performance and cerebral functional response during working memory in schizophrenia.

Working memory dysfunction is considered to be fundamental to the cognitive and clinical features evident in schizophrenia. Functional neuroimaging studies have begun to elucidate the neurobiological basis of such deficits, however, interpretation of these studies may be confounded by performance impairment, when the cognitive load exceeds the limited response capacity of patients with schizophrenia. In this study, patients were pre-selected on the basis of intact performance on a relatively low-load verbal working memory task, in order to mitigate against performance confounds. Subjects included 20 right-handed male subjects with chronic schizophrenia, and 20 right-handed, age-matched, male healthy controls, without personal or familial psychiatric history. All subjects underwent fMRI scanning whilst performing a verbal n-back task. There were no significant between-group differences in target identification; the patient group showed a significantly increased mean response latency. Both groups demonstrated robust fronto-parietal activation. In the control subjects, the power of functional response was positively correlated with reaction time in bilateral posterior parietal cortex, however, this coupling of behavioural performance and cerebral response was not evident in the patients. This deficit, apparent within the performance capacity of the patients, may represent a fundamental abnormality in schizophrenia, and may compromise performance at higher cognitive loads.     

3,5-甾二烯化合物的合成及抗早孕活性

以18-甲基-17β-羟基-17α-乙炔基-雌甾-4-烯-3-酮(18-甲基炔诺酮),17β-羟基-17α-乙缺基-雌甾-4-烯-3-酮(炔诺酮),17β-羟基-17α-乙炔基-雄甾-4-烯-3-酮(妊娠素)和17a-羟基孕甾-4-烯-3,20二酮(17α-羟基黄体酮)为原料,经NaBH,还原、脱水、双键转位和酯化等反应合成一系列3,5-甾二烯化合物,用¹HNMR和MS证明了它们的结构。动物筛选结果表明,17β-丙酰氧基-17α-乙炔基-雌甾-3,5-二烯(IV_b2有明显的抗早孕活性。中断早期妊娠的作用似与其雌激素活性有关。     

Evaluation of encephalic ventricular volume from the magnetic resonance imaging scans of thirty-eight human subjects

Summary Accurate volume determination of the encephalic ventricles is of importance in several clinical conditions, including Alzheimer's presenile dementia, schizophrenia, and benign intracranial hypertension. Previous studies have investigated the accuracy with which magnetic resonance imaging (MRI) can be used in clinical practice to evaluate the encephalic ventricles. However, adequate evaluation of pathological conditions depends on a sufficient amount of morphometric data from normal subjects. To begin establishing this data base for normal subjects, we evaluated the MRI scans of 38 subjects found to have no apparent pathology and calculated the ventricular volume in each case by using methods previously developed in our laboratory. The results were then compared with published volumes determined from studies that used either ventricular casts or computerized tomographic scans. The average total ventricular volume for all 38 subjects was 17.4 cm³, while that for males was 16.3 cm³ and that for females was 18.0 cm³. A small but significant correlation was found between age of subject and ventricular volume, with ventricular size increasing with age.

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Evaluation du volume des ventricules cérébraux à partir des images obtenues en résonance magnétique nucléaire chez 38 sujets humains

Résumé La détermination exacte du volume des ventricules cérébraux est importante en clinique comme par exemple dans la démence présénile d'Alzheimer, la schizophrénie et l'hypertension intracrânienne bénigne. Des études antérieures ont étudié la fiabilité de la résonance magnétique nucléaire en pratique clinique pour évaluer le volume des ventricules cérébraux. Toutefois une évaluation correcte dans les conditions pathologiques implique une bonne connaissance des données morphométriques du sujet normal. Pour établir ces données sur « le sujet normal », nous avons étudié les coupes obtenues en IRM chez 38 sujets apparemment indemnes de toute pathologie; nous avons calculé le volume ventriculaire dans chaque cas en utilisant des méthodes mises au point auparavant dans notre laboratoire. Les résultats ont été ensuite comparés avec ceux obtenus par d'autres études utilisant soit des moules ventriculaires, soit des coupes tomographiques computérisées. Le volume ventriculaire total moyen chez 38 sujets est de 17,4 cm³, mais il est chez les sujets masculins de 16,3 cm³ et chez les sujets de sexe féminin de 18 cm³. Une corrélation faible mais significative a été trouvée entre l'âge du sujet et le volume ventriculaire, étant entendu que la taille du ventricule augmente avec l'âge.

     

Thymocyte expression of cathepsin L is essential for NKT cell development

CD1d antigen presentation to natural killer T (NKT) cells expressing the semi-invariant T cell receptor V(alpha)14J(alpha)18 requires CD1d trafficking through endosomal compartments; however, the endosomal events remain undefined. We show that mice lacking the endosomal protease cathepsin L (catL) have greatly reduced numbers of V(alpha)14(+)NK1.1(+) T cells. In addition, catL expression in thymocytes is critical not only for selection of these cells in vivo but also for stimulation of V(alpha)14(+)NK1.1(+) T cells in vitro. CD1d cell-surface expression and intracellular localization appear normal in catL-deficient thymocytes, as does the lysosomal morphology; this implies a specific role for catL in regulating presentation of natural CD1d ligands mediating V(alpha)14(+)NK1.1(+) T cell selection. These data implicate lysosomal proteases as key regulators of not only classical major histocompatibility complex class II antigen presentation but also nonclassical CD1d presentation.     

Empowerment versus power: consumer participation in mental health services

Consumer participation is regarded as increasingly important in the effective delivery of mental health services and for the empowerment of mental health consumers. In a qualitative study, 17 consumers and 10 occupational therapists discussed their perceptions of consumer participation in mental health services. These included the advantages and benefits of consumer participation, the barriers to participation and how health workers can facilitate participation. The research brought to light an uncertain relationship between empowerment and power. While empowerment was universally considered to be desirable, opinions about the transfer of power were more ambivalent. It is argued that consumers and health workers need to work together to find creative ways of addressing concerns relating to power so that real power can be shared to benefit all consumers. Limitations of the study included the small sample size and the sampling method, which restricted access to potential participants. Further research is suggested into consumer participation and consumer power. Copyright © 1999 Whurr Publishers Ltd.     

Congenital pulmonary atresia with ventricular septal defect: angiographic and surgical correlates

Of 181 patients with severe congenital pulmonary atresia and ventricular septal defect or "type IV truncus" (an obsolete term), all but 11% had true central pulmonary arteries. These arteries were demonstrable by large serial biplane angiograms using multiple selective injections into collateral vessels, frequent photographic subtraction, and occasional pulmonary vein-wedge angiograms. These techniques are extremely important for accurate diagnosis and in planning corrective or palliative surgery, which was done in 77% of patients with pulmonary arteries.     

Variation in clinical outcome following shock wave lithotripsy

PURPOSE: We measure and compare operator specific success rates of extracorporeal shock wave lithotripsy (ESWL) performed by 12 urologists in 1 unit to determine interoperator variation. MATERIALS AND METHODS: From January 1, 1994 to September 1, 1997 a total of 5,769 renal and ureteral stones received 9,607 ESWL treatments by 15 urologists with a Dornier MFL 5000 lithotriptor. The 3-month followup data are available for 4,409 stones. Outcome measures consisted of patient demographics, stone characteristics, technical details of lithotripsy, and stone-free and success rates by treating urologists. RESULTS: Treatment results were analyzed for 12 urologists (surgeons A to L) who treated more than 100 stones each, totaling 4,244 with followup information available. Mean stone-free and success rates were 50.6% and 72.3%, respectively. Surgeon A had significantly higher stone-free and success rates of 56.2% and 76.7%, respectively (p<0.05), with treatment results from 877 stones, which was a significantly higher number than others (p<0.05). Significant differences existed in mean number of shocks delivered among urologists (p = 0.0001), with surgeons A and J delivering the highest mean numbers (2,317 and 2,801, respectively). There was no difference in treatment duration (p = 0.75) but variation existed among urologists in terms of mean maximum treatment voltage (p = 0.0001). Mean fluoroscopy time at 4.1 minutes was higher for surgeon A than others (p<0.05). Mean complication rate following ESWL was 4.9% with no difference among urologists (p = 0.175). Re-treatment was required in 21.7% of cases and surgeon A had the lowest rate (15.9%, p<0.05). CONCLUSIONS: We demonstrated clinically and statistically significant intra-institutional differences in success rates following ESWL. The best results were obtained by the urologist who treated the greatest number of patients, used a high number of shocks and had the longest fluoroscopy time. Accurate targeting is crucial when using a lithotriptor, such as the Dornier MFL 5000, with a narrow focal zone of 6.5 mm. in diameter. Other centers should be encouraged to develop similar programs of outcome analysis in an attempt to improve performance.