Heterodetic bicyclic decapeptide cyclo (Glu1 -Leu2 -Pro3-Gly4-Ser5-Ile6-Pro7-Ala8) cyclo-(1γ-5β) Phe9-Gly10

Bycyclic peptides are useful model molecules that can mimic the constrained local folding of a great number of natural peptides and proteins, such as ionophoric peptides, enzyme active site, and ligand-receptor active site. The synthesis of the bicyclic title compound with the liquid phase method is described with experimental details. Of particular interest is the heterodetic closure of the second ring. The peptide showed a complexing activity with metal cations like Ba²⁺, Ca²⁺, and Mg²⁺ . The free bicyclic peptide conformation in solution has been studied by means of NMR spectroscopy and a plausible structure model worked out with model building on NMR constraints is proposed.     

Nonlinear sensory cortex response to simultaneous tactile stimuli in writer's cramp.

Writer's cramp is a task-specific dystonia that leads to involuntary hand postures during writing. Abnormalities of sensory processing may play a pathophysiological role in this disorder. Electrophysiology studies in a monkey model of focal dystonia have revealed de-differentiation of sensory maps and the existence of single cells in hand regions of area 3b with enlarged receptive fields that extend to the surfaces of more than one digit. These changes may lead to abnormal processing of simultaneous sensory inputs. To study abnormal processing of simultaneous sensory information in adult humans with writer's cramp, we used functional magnetic resonance imaging to compare the response in primary sensory cortex with simultaneous tactile stimulation of the index and middle finger, with the response to stimulation of each finger alone. We tested five patients with writer's cramp and seven unaffected (normal) subjects. In the normal subjects, a linear combination of the activation patterns for individual finger stimulation predicts the pattern of activity for combined stimulation with 12% error. In writer's cramp patients, the linear combination predicted the combined stimulation pattern with 30% error. Results indicate a nonlinear interaction between the sensory cortical response to individual finger stimulation in writer's cramp. This altered interaction may contribute to the motor abnormalities.     

旋磁场对胆结石病人胆汁中胆红素、钙、胆固醇和pH的影响

目的 探讨旋磁场与大面积静磁场对置对胆结石病人胆汁中总胆红素（BIT）、直接胆红素（BID）、间接胆红素（BII）、钙（Ca）、胆固醇（CH）和pH的影响。方法 旋磁组30例,测定旋磁处理前后65对胆汁样本。空白对照组15例,留取前后30对胆汁样本。将直径12mm圆形稀土永磁片110块,表面磁感应强度210mT,分别间隔10mm贴于210mm×220mm铁皮上形成一个大面积磁板与旋磁头表面静磁感应强度160mT,旋转平均表面磁感应强度100mT呈异名极对置,磁板置肝区背侧,旋磁头置剑突下处理40min。结果 旋磁组胆结石病人胆汁（n=65）:经旋磁场与磁板对置处理前减去处理后差值的x±s和t值分别为BIT41.81±93.52、3.59;BID 13.57±43.70、2.46;BII28.27±61.67、3.32;Ca 0.19±0.31、4.87;CH0.12±0.29、3.36;pH 0.01±0.27、0.30。除pH外,其余各项指标P值均<0.05。对照组胆汁（n=30）:间隔时间前后差值的x±s和t值分别为BIT4.42±22.05、1.14;BID2.40±12.37、1.06;BII2.52±46.27、0.30;Ca0.01±0.18、0.50;CH0.03±0.15、0.94;pH 0.009±0.06、0.84。P值均>0.05。结论 在本项磁场类型、强度和时间处理条件下,旋磁场与磁板对置能明显影响胆结石病人胆汁中的BIT、BID、BII、Ca和CH的浓度变化,且有显著降低的作用。     

New insights on COPD imaging via CT and MRI

Multidetector-row computed tomography (MDCT) can be used to quantify morphological features and investigate structure/function relationship in COPD. This approach allows a phenotypical definition of COPD patients, and might improve our understanding of disease pathogenesis and suggest new therapeutical options. In recent years, magnetic resonance imaging (MRI) has also become potentially suitable for the assessment of ventilation, perfusion and respiratory mechanics. This review focuses on the established clinical applications of CT, and novel CT and MRI techniques, which may prove valuable in evaluating the structural and functional damage in COPD.     

经颅彩色双功超声在脑血管疾病中的临床应用和进展

经颅彩色双功超声是一种新型、无创的超声诊断仪,高空间分辨率显示颅内血管和脑实质的结构,笔者查阅了近年来相关文献,主要综述经颅彩色多普勒血流显像在颅脑血管疾病中的诊断价值,同时讨论二维经颅超声的应用及新的实验性显像技术。     

Biophysical foundations underlying TMS: Setting the stage for an effective use of neurostimulation in the cognitive neurosciences

Transcranial Magnetic Stimulation (TMS) induces electrical currents in the brain to stimulate neural tissue. This article reviews our present understanding of TMS methodology, focusing on its biophysical foundations. We concentrate on how the laws of electromagnetic induction apply to TMS; addressing issues such as the location, area (i.e., focality), depth, and mechanism of TMS. We also present a review of the present limitations and future potential of the technique.     

卡铂碳包铁纳米笼壳聚糖微球 在肝癌大鼠模型体内的分布和药动学研究

 目的 观察卡铂碳包铁纳米笼壳聚糖微球 （ carboplatin-Fe@C-loaded chitosan nanoparticles ， C - Fe@C-CN ）结合磁场在移植性肝癌大鼠模型体内的靶向分布情况和药动学过程。 方法 建立移植性肝癌大鼠模型 40 只为 A 组， 正中开腹行肝动脉插管，按卡铂 5 mg·kg^-1 体重注入 C-Fe@C-CN 的生理盐水分散液，以肿瘤组织为靶区施加 0.5 T 磁场 30 min 。分别在给药后 0.25 ， 0.5 ， 1 ， 3 ， 6 ， 12 ， 24 和 48 h 各时间点，每组取 5 只大鼠处死，采集血浆、靶区肿瘤、非靶区肝、肾、脾和肺组织标本，石墨炉原子分光光度计测定血浆和组织中卡铂浓度，药物浓度数据用 3P87 药动学程序分析处理，并组织学 观察 C-Fe@C-CN 的在各脏器分布情况。 另 40 只健康大鼠为 B 组，以左肝叶为靶区，给予相同的处理作为对照。 结果 A 组靶区肿瘤组织 <> c _max 是 65.21 μg·g^-1 ，为 B 组靶区肝组织（ 38.47 μg·g^-1 ）的 1.7 倍。 48 h 时 A 组靶区肿瘤组织药物浓度是 7.27 μg·g^-1 ，为 B 组靶区肝组织（ 3.11 μg·g^-1 ）的 2.3 倍。 A 组靶区肿瘤组织 AUC 是 906 mg·h·L^-1 ，为 B 组靶区肝组织（ 421.34 mg·h·L^-1 ）的 2.2 倍。 2 组药动学参数值相近。病理学观察 显示， C-Fe@C-CN 在磁场作用下聚集于肿瘤细胞间隙中，并可栓塞于部分细小动脉。非靶区肝组织内少见 C-Fe@C-CN 的聚集和栓塞的血管。 结论 C-Fe@C-CN 在体内具有长循环和缓释特性，在磁场的引导下对肿瘤组织具有更强的靶向性，成倍提高肿瘤组织中的药物浓度，延长维持时间。     

乳腺良恶性病变的磁共振T2*W首过灌注成像与血管生成相关性研究

Objective： To study the diagnostic value of T2^＊-weighted first-pass perfusion imaging in breast tumors. Methods： We analyzed the magnetic resonance imaging （MRI） information along with the pathological and immunohistochemistry results. Magnetic resonance imaging was performed in 28 patients with breast tumor. The time to signal intensity curves were generated according to the T2^＊-weighted first-pass perfusion imaging. The curve＇s maximal signal intensity drop rate and maximal signal intensity decrease time were analyzed and compared with the pathological diagnoses after surgery. Results： Malignant breast lesions showed higher maximal signal intensity drop rate （44.69% ± 17.07 vs. 17.22% ±7.49, P 〈 0.001） than benign lesions, but there was no significant difference of maximal signal decrease time between those two lesions （23.94 s ± 4.92 vs. 20.02 s ± 6.83, P 〉 0.05）. Conclusion： The T2^＊-weighted first-pass perfusion imaging has enough sensitivity and specificity in breast tumor diagnosis.     

Stimulation by mitogens and neuronal membranes of lymphocytes from patients with motor neurone disease

Stimulation of lymphocytes from motor neurone disease patients by either concanavalin A or PHA was shown to be significantly depressed relative to that from normal controls, as assayed by incorporation of [3H]thymidine or [3H]leucine or by glucose uptake. Corresponding significant differences were not shown by assays based upon incorporation of [3H]uridine or of lactate release. Lymphocytes from 4 out of 14 motor neurone disease patients showed a blastogenic response to membranes from rat spinal cord cells, compared with those from 0 out of 9 normal controls. These results not only suggest the possibility of an impaired cellular immune control in MND patients but also indicate the presence of lymphocytes sensitised specifically to neuronal membrane components.