补充维生素D预防骨折——随机对照试验汇总分析

背景：对于脊椎以外的骨折而言，补充口服维生素D的预防作用和用量仍无定论。 目的：评估补充维生素D在预防老年髋骨骨折和非脊椎骨折方面的效果。 数据来源：使用MEDLINE、Cochrance对照试验记录（1960～2005年）以及EMBASE（1991-2005年），对英文和非英文文章进行系统回顾。通过与临床专家接触，通过检索美国社会骨和骨矿研究协会提供的参考文献和摘要（1995～2004年）．进一步寻找更多的研究。检索词包括随机对照试验（randomized controlled trial，RCT）、临床对照试验、随机分配、双盲法、维生素D3、维生素D2；25-羟基维生素D、骨折、人类、老年、摔倒和骨密度。 研究选取：纳入的研究仅限于口服补充维生素D（维生素D3、维生素D2、补钙或不补钙）与补钙或安慰剂比较的双盲RCTs。试验于检查髋部骨折或非脊椎骨折的老年人（年龄≥60岁）中进行。数据提取：两位作者根据预先规定独立提取相关数据，其中包括研究质量指标。 数据综合：所有的汇总分析均以随机效应模型为基础。5项有关髋部骨折的RCTs（n=9294）和7项有关非脊椎骨折危险的RCTs（n=9820）符合我们的纳入标准。所有试验均使用了维生素D3。对髋部和非脊椎骨折预防研究的异质性亦进行观察，用低剂量（400IU／d）和高剂量（700～800IU／d）分别合并RCTs后异质性消失。与补钙或安慰剂相比，每天服700～800IU的维生素D可使髋部骨折的相对危险（relative risk，aa）下降26％（3项RCTs共计5572人；RR，0．74；95％可信区间[confidence interval，CI]，0．61～0．88），使非脊椎骨折的相对危险下降23％（5项RCTs共计6098人；RR，0．77；95％CI，0．68～0．87）。每天服400IU的维生素D（2项RCTs共计3722人；髋部骨折RR，1．15；95％CI，0．88～1．50；非脊椎骨折RR，1．03；95％CI，0．86—1．24）未见明显获益。 结论：口服补充维生素D（700～800IU／d）可以降低尚能活动的老人或慈善机构收容的老年人发生髋部骨折和脊椎以外骨折的危险，每天口服400IU维生素D并不足以预防骨折。     

Dobutamine magnetic resonance imaging as a predictor of myocardial functional recovery after revascularisation

OBJECTIVE—To assess the use of dobutamine magnetic resonance imaging (MRI) as a preoperative predictor of myocardial functional recovery after revascularisation, comparing wall motion and radial wall thickening analyses by observer and semi-automated edge detection.
PATIENTS—25 men with multivessel coronary disease and resting wall motion abnormalities were studied with preoperative rest and stress MRI.
MAIN OUTCOME MEASURES—Observer analysis for radial wall thickening was compared with a normal range, while wall motion analysis used a standard four point scale. Semi-automated analysis was performed using an edge detection algorithm. Segments displaying either improved or worsened thickening or motion with dobutamine were considered viable. Postoperative rest images were performed 3-6 months after coronary artery bypass grafting (CABG) for comparison.
RESULTS—For observer analysis the values for sensitivity and specificity were 50% and 72% for wall motion, with respective values of 50% and 68% for thickening. With semi-automated edge detection the figures for motion were 60% and 73%, with corresponding values of 79% and 58% for thickening. Combining thickening and motion for the semi-automated method to describe any change in segmental function yielded a sensitivity of 71% and specificity of 70%.
CONCLUSIONS—Dobutamine MRI is a reasonably good predictor of myocardial functional recovery after CABG. The use of semi-automated edge detection analysis improved results.


Keywords: dobutamine; magnetic resonance imaging myocardial viability; coronary artery bypass grafting     

Differential effects of tryptophan depletion on emotion processing according to face direction

Reading facial emotion is disrupted by both psychopathology,such as autism, and altered function of neurotransmitter, suchas serotonin. These effects could result from reduced sensitivityof emotional processing systems to facial emotion. The impactof facial expression is also greater when personally directedthan when averted. We therefore hypothesized that brain activityassociated with emotional representation, would be more susceptibleto manipulation of serotonin function by Acute Tryptophan Depletion(ATD) for front-viewed than side-viewed faces, measured usingfunctional imaging (fMRI). ATD reduced activity independentof face view in left superior temporal sulcus (STS) and anteriorcingulate. In temporal pole, medial frontal cortex and orbitofrontalcortex, ATD also reduced activity, but specifically for front-viewedfaces. In right STS, ATD increased activity, but specificallyfor side-viewed faces. Activity in the amygdalae depended onface view and emotion type. We suggest that engagement of empathicand associative learning functions when viewing faces is facilitatedby direct facial view and intact serotonin transmission. Avertedfaces, and reduced serotonin function facilitate attention tothe external goal of gaze. These changes could be adaptive ina threatening context and markedly affect empathic functionin conditions associated with impaired serotonin function, suchas depression and autism.     

Is retaining the youthful functional anatomy underlying speed of information processing a signature of successful cognitive ageing? An event-related fMRI study of inspection time performance

It has been hypothesized that individual differences in cognitive ageing might in part be based on the relative preservation of speed of information processing. However, the biological foundations of processing speed are not understood. Here we compared two groups of non-demented older people who had relatively similar IQs at age 11 but differed markedly in non-verbal reasoning ability at age 70: 'cognitive sustainers' (n=25), and 'cognitive decliners' (n=15). Using an event-related fMRI design, we studied the BOLD response while they performed an inspection time task. Inspection time is a two-alternative forced choice, backward masking test of the speed of the early stages of visual information processing. Inspection time has a well-established, significant association with higher cognitive abilities. The group of cognitive sustainers showed a pattern of BOLD activation-deactivation in response to inspection time stimulus duration differences that was similar to a healthy young sample [Deary, I.J., Simonotto, E., Meyer, M., Marshall, A., Marshall, I., Goddard, N., Watdlaw, J.M., 2004a. The functional anatomy of inspection time: an event-related fMRI study. NeuroImage 22, 1466-1479]. The group of cognitive decliners lacked these clear neural networks. The relative preservation of complex reasoning skills in old age may be associated with the preservation of the neural networks that underpin fundamental information processing in youth.     

Puddles, parties, and professors: linking word categorization to neural patterns of visuospatial coding

Behavioral evidence suggests that during word processing people spontaneously map object, valence, and power information to locations in vertical space. Specifically, whereas "overhead" (e.g., attic), positive (e.g., party), and powerful nouns (e.g., professor) are associated with "up," "underfoot" (e.g., carpet), negative (e.g., accident), and powerless nouns (e.g., assistant) are associated with "down." What has yet to be elucidated, however, is the precise nature of these effects. To explore this issue, an fMRI experiment was undertaken, during which participants were required to categorize the position in which geometrical shapes appeared on a computer screen (i.e., upper or lower part of the display). In addition, they also judged a series of words with regard to location (i.e., up vs. down), valence (i.e., good vs. bad), and power (i.e., powerful vs. powerless). Using multivoxel pattern analysis, it was found that classifiers that successfully distinguished between the positions of shapes in subregions of the inferior parietal lobe also provided discriminatory information to separate location and valence, but not power word judgments. Correlational analyses further revealed that, for location words, pattern transfer was more successful the stronger was participants' propensity to use visual imagery. These findings indicate that visual coding and conceptual processing can elicit common representations of verticality but that divergent mechanisms may support the reported effects.     

No causal relationship between transdermal scopolamine and seizures: methodologic lessons for pharmacoepidemiology

Because of case reports suggesting that use of transdermal scopolamine might be associated with the subsequent development of seizures, a retrospective cohort study was performed with computerized Medicaid claims data. Patients receiving transdermal scopolamine were compared with patients receiving diphenhydramine, meclizine, prochlorperazine, and promethazine. A four-fold increased risk of seizures after transdermal scopolamine use was observed in the claims data. However, this was not supported by the primary medical records. All patients who had seizures after using transdermal scopolamine either had seizures before receiving the drug as well or did not really suffer from seizures. The original finding appeared to be the result of the use of transdermal scopolamine for "dizziness, rule out seizures"; the ICD-9-CM coding system does not include "rule out" diagnoses. Thus these data do not confirm the existence of an association between seizures and the use of transdermal scopolamine. In addition, this study demonstrates the usefulness of pharmacoepidemiology studies in documenting drug safety and the importance of obtaining primary medical records when performing pharmacoepidemiologic studies with claims data.     

An fMRI study of joint attention experience

Although much is now known about eye movement detection, little is known about the higher cognitive processes involved in joint attention. We developed video stimuli which when watched, engender an experience of joint attention in the observer. This allowed us to compare an experience of joint attention to nonjoint attention within an fMRI scanning environment. Joint attention was associated with activity in the ventromedial frontal cortex, the left superior frontal gyrus (BA10), cingulate cortex, and caudate nuclei. The ventromedial frontal cortex has been consistently shown to be activated during mental state attribution tasks. BA10 may serve a cognitive integration function, which in this case seems to utilize a perception-action matching process. The activation we identified in BA10 overlaps with a location of increased grey matter density that we recently found to be associated with autistic spectrum disorder. This study therefore constitutes evidence that the neural substrate of joint attention also serves a mentalizing function. The developmental failure of this substrate in the left anterior frontal lobe may be important in the etiology of autistic spectrum disorder.