Brainstem 1H nuclear magnetic resonance (NMR) spectroscopy: Marker of demyelination and repair in spinal cord

Measuring in vivo spinal cord injury and repair remains elusive. Using magnetic resonance spectroscopy (MRS) we examined brainstem N‐acetyl‐aspartate (NAA) as a surrogate for spinal cord injury in two mouse strains with different reparative phenotypes following virus‐induced demyelination. Swiss Jim Lambert (SJL) and Friend Virus B (FVB) mice progressively demyelinate with axonal loss. FVB mice demyelinate similarly but eventually remyelinate coincident with functional recovery. Brainstem NAA levels drop in both but recover in FVB mice. Chronically infected SJL mice lost 30.5% of spinal cord axons compared to FVB mice (7.3%). In remyelination‐enhancing or axon‐preserving clinical trials, brainstem MRS may be a viable endpoint to represent overall spinal cord dysfunction. Ann Neurol 2009;66:559–564     

儿童腹部囊性肿块CT分析

目的分析儿童腹部囊性肿块CT特征。方法分类统计临床病理证实的101例儿童腹部囊性肿块,总结其CT特征。结果①真性囊肿30例（29．7％）,其CT表现相似。②假性囊肿14例（13．8％）,其中胰腺假性囊肿11例、脑脊液假性囊肿3例,CT表现各异。③囊性畸形26例（25．7％）,其中肠系膜囊肿8例,网膜囊肿4例,胃肠道重复畸形3例,胆总管囊肿9例,脐尿管囊肿2例,其CT表现多呈光滑的囊性肿块。④囊性肿瘤24例（23．8％）,其中囊性畸胎瘤13例,多发生在腹膜后、卵巢和骶尾部;浆液性和粘液性囊腺瘤各4例,发生在卵巢和胰腺,4例浆液性囊腺瘤CT呈微腔肿瘤,4例粘液性囊腺瘤CT呈大囊病灶;2例肝脏间充质错构瘤,CT呈低密度多房性肿块;1例多房性囊性肾瘤,CT呈边界清楚、厚度不均的多分隔肿块。⑤腔道积水、积脓7例（6．9％）,其中单侧肾积水5例,阑尾脓肿2例。结论儿童腹部最常见囊性肿块是真性囊肿,其次是囊性畸形、囊性肿瘤和假性囊肿,其CT表现各有特征。     

Free-paced high-performance brain-computer interfaces

Neural prostheses aim to improve the quality of life of severely disabled patients by translating neural activity into control signals for guiding prosthetic devices or computer cursors. We recently demonstrated that plan activity from premotor cortex, which specifies the endpoint of the upcoming arm movement, can be used to swiftly and accurately guide computer cursors to the desired target locations. However, these systems currently require additional, non-neural information to specify when plan activity is present. We report here the design and performance of state estimator algorithms for automatically detecting the presence of plan activity using neural activity alone. Prosthesis performance was nearly as good when state estimation was used as when perfect plan timing information was provided separately ( approximately 5 percentage points lower, when using 200 ms of plan activity). These results strongly suggest that a completely neurally-driven high-performance brain-computer interface is possible.     

Smarter screening for prostate cancer: for the few, not the many? A stratified approach based on baseline risk

Evaluation of: van Leeuwen PJ, Connolly D, Tammela TLJ et al. Balancing the harms and benefits of early detection of prostate cancer. Cancer 116(20), 4857-4865 (2010). Prostate cancer screening remains controversial, with different countries taking different views on its value. We review the study by van Leeuwen and colleagues, evaluating the risk-benefit ratio for screening from the European Randomized study of Screening for Prostate Cancer (ERSPC) stratified by age and serum prostate-specific antigen level at study entry. Though the overall results from the ERSPC demonstrated a 20% relative reduction in prostate cancer mortality in the screened arm, the current study demonstrated that the benefit was minimal for men aged 55-74 years with a serum prostate-specific antigen <4 ng/ml and came at the expense of significant overdiagnosis and overtreatment. This study adds to the growing body of evidence that prostate cancer screening works, but not for everyone, and suggests a smarter strategy of targeted screening to those most at risk from prostate cancer mortality.     

HIV-1 Tat-specific IgG antibodies in high-responders target a B-cell epitope in the cysteine-rich domain and block extracellular Tat efficiently

Tat, an important regulatory protein of HIV-1, has been implicated in HIV-related pathogenesis. Immune responses to Tat, although underrepresented, confer protection against disease progression, in natural infection and experimental immunization, making Tat an attractive vaccine candidate. Information on immune responses to Tat from India which has the second largest HIV incidence has been lacking. Here we report a cross-sectional study evaluating the humoral response to Tat from a large number of samples from two southern states of India. 14% of the seropositive (63/447) and 4.6% of seronegative samples (7/150) harbored Tat-reactive antibodies. A significant number of the seropositive samples contained high levels of anti-Tat antibodies (31/447) which demonstrated class-switch to IgG1 and bound to Tat with high avidity. Cross-reactivity analysis showed that these antibodies interacted with Tat from different clades with variable degree withthe highest interaction with subtype-AE and the least with subtype-B Tat. Importantly, a B-cell epitope in the cysteine-rich domain was found to be the most immunodominant one and antibodies interacting with this epitope blocked extracellular Tat efficiently. To the best of our knowledge this is the first report on immune responses to Tat from Indian populations and the data presented here could significantly contribute to HIV Tat vaccine design.