Mutational analysis of immunoglobulin E-binding epitopes of β-casein and β-lactoglobulin showed a heterogeneous pattern of critical amino acids between individual patients and pooled sera

BACKGROUND: For immunotherapeutic approaches, 'critical' amino acids (AAs) within allergenic epitopes are replaced with alternate AAs to eliminate IgE antibody binding. OBJECTIVE: To determine the critical AAs for IgE binding in beta-casein and beta-lactoglobulin (BLG). METHODS: Peptides of 10-14 AAs in length were synthesized on a derivatized cellulose membrane with single AA substitutions (alanine or glycine) at each position. Membranes were incubated with a pool of sera from 15 cow's milk-allergic patients and individual sera from six of the 15 patients. In cases where no decrease in binding occurred with a single AA substitution, peptides with two AA substitutions were generated and labelled. RESULTS: Using pooled patient sera, single AA substitutions led to complete elimination of binding to six of 11 peptides for beta-casein and to all six peptides for BLG. Substituting two AAs led to an elimination of binding to four of the remaining five beta-casein epitopes. However, in three of the 11 modified beta-casein peptides and five of the six BLG peptides, no decrease in IgE binding occurred in at least one individual patient. For these patients, critical AAs other than those defined by the patient serum pool were identified, indicating a heterogeneous pattern of IgE recognition. CONCLUSION: These results indicate that AAs critical for IgE binding are more heterogeneous than initially defined by pooled milk-allergic patient sera. For future immunotherapeutic interventions with mutated peptides, critical AAs should also be identified with individual patient sera to account for heterogeneity of IgE binding between patients.     

下颌骨侧位摄影X线中心线倾斜角度与垫板倾斜角度关系之探讨

目的探讨下颌骨侧位摄影分别采用一倾斜角度为α的垫板及未采用时，X线中心线倾斜角度各为β、γ之间的关系，为更简捷地拍好下颌骨提供理论参数和实践依据。方法立足于教科书，运用X线摄影原则与数学几何原理进行推理演绎。结果二者之间存在着可替换的关系，即γ=α＋β，可以大胆地去除垫板进行直接拍摄。结论不用垫板，只需通过增大X线中心线倾斜角度的方法，同样也能拍摄出一张好照片，且可操作性强，简便易行，实际使用价值更大。     

小儿糜烂性口腔炎病毒病因及干扰素对病毒的抑制作用

本文研究了小儿糜烂性口腔炎的病毒病因,用人胚肾细胞及Hep—2细胞分离病毒,26例患儿有21例阳性(80.7％),从中取五株病毒进行鉴定,细胞病变特点属疱疹病毒,且均可被抗HSV—I抗体中和,结果表明HSV—I是本病的主要病原。体外实验证明,白细胞干扰素对新分离的HSV—I有较强的抑制病变作用,2.4～2.9Iu/ml白细胞干扰素即可抑制病毒的50％CPE。临床上试用干扰素局部治疗必获得显著的疗效。     

Flavonoids from the leaves ofRhododendron brachycarpum

The flavonoids isolated from the leaves ofRhododendron brachycarpum, were identified as quercetin, avicularin, quercitrin and hyperin.     

食管癌患者与对照组血清维生素A水平分析

目的:为了解食管癌患者和非食管癌患者体内维生素A的水平及其与食管癌发病的关系.方法:采用微量荧光法对32例食管癌患者(实验组)和32例非食管癌患者(对照组)血清中维生素A含量进行了测定.结果:显示实验组与对照组血清维生素A均值分别为1.55μmol/L,1.69μmol/L.经统计学处理两组血清维生素A水平有显著性差异(P<0.01).结论:提示食管癌的发生可能与机体维生素A水平有关,这种关系需进一步探讨.     

蝎毒素Ⅳ的中枢镇痛作用

从东亚钳蝎粗毒中分离纯化出蝎毒素Ⅳ，经套管注入侧脑室，用辐射热测痛和屈肌反射检测两种方法，观察蝎毒素Ⅳ的中枢镇痛作用，结果蝎毒索Ⅳ可以明显延长大鼠缩腿潜伏期，并可显著抑制Ｃ纤维诱发的屈肌反射。提示蝎毒素Ⅳ具有显著的中枢镇痛作用。     

Neural networks in the study of the brain

Neural networks are models of the brain and have been used within Artificial Intelligence to provide alternative explanations to the symbolic explanations of cognition in which one assumes that an intelligent system has certain explicit representations of some aspect of the world and uses these in intelligent behavior. Obviously, if neural networks are indeed good models of the brain, and give a satisfactory account of cognition, then they could be a valuable tool to neuroscientists. This article gives a brief overview of the various neural network models, and critically reviews their status as models of the brain and of cognition.