Peptides derived from IgE heavy chain constant region induce profound IgE isotype-specific tolerance

(BALB/c × SJL)F1 mice, perinatally injected with peptide-N-glyconase F-treated, deglycosylated IgE heavy chain or recombinant IgE heavy chain (CH?2-CH?4), were profoundly inhibited in antigen-specific IgE production. There exist minimally two tolerogenic IgE peptides, residing in the CH?2 and CH?4 domains. Peptide I, generated by V8 protease, comprises 39 amino acids within CH?2, beginning at amino acid 103. Peptide E begins at amino acid 312 of the CH?4 domain and extends through the CH?4 domain. The total lack of antigen-specific IgE responses in IgE peptide-treated mice was not due to overproduction of interferon-γ, nor lack of interleukin (IL)-4, as predicted by the Th2/IL-4 paradigm for IgE production. IgE-tolerant mice exhibited comparable levels of circulating anti-IgE antibodies to those of PBS-treated control mice. IgG obtained from sera of both sources failed to inhibit IgE responses in vitro. Moreover, IgE responses of spleen cells from IgE peptides-treated mice were restored by CD4⁺ T cells from PBS-treated control mice. We hypothesize that regulation of antigen-specific IgE responses is mediated by CD4⁺ T cells which normally recognize IgE peptides on IgE precursor B cells, and can be rendered tolerant by perinatal IgE peptide treatment.     

高效凝胶色谱一步法制备级纯化单克隆抗体

作者采用ＰｈａｒｍａｃｉａＳｅｐｈａｃｒｙｌＳ—３００凝胶色谱柱，建立了ＩｇＧ类ＭｃＡｂ的一步法制各级纯化方法。该法是将ＭｃＡｂ腹水直接上样，用ｐＨ７．４１０ｍｍｏｌ／ＬＰＢＳ洗脱（流速０．５ｍｌ／ｍｉｎ），即得到纯化的ＭｃＡｂ。一次上样量４０～５０ｍｌ腹水，回收率为８５％－９０％．整个纯化周期４ｈ。纯化的ＭｃＡｂ经ＳＤＳ—ＰＡＧＥ测定，纯度＞９０％，免疫组化ＡＢＣ法测定活性为１：８００００（７．８×１０－１１ｍｏｌ／Ｌ）。该法操作简单、快速，只要有一台核酸／蛋白检测仪，便可进行制备级水平的纯化。     

采用IL－6cDNA控针检测人IL－6基因表达

采用缺口平移技术对ＩＬ—６ｃＤＮＡ进行了生物素和同位素标记，证明两种标记的ＩＬ－６ｃＤＮＡ（３０ｎｇ／ｍｌ）均可检出低至５ｐｇ的同源ＤＮＡ，而模拟探针（５００μｇ／ｍｌ）对高达１００ｎｇ的同源序列无此反应。应用ＩＬ－６ｃＤＮＡ对富含ＩＬ－６ｍＲＮＡ的标本进行斑点杂交或Ｎｏｒｔｈｅｒｎ杂交，证明人参三醇皂甙促进了淋巴细胞ＩＬ—６基因表达（４倍），人胎脾单个核细胞、人胎脑组织匀浆和人胎胰岛细胞内均含有高浓度ＩＬ—６ｍＲＮＡ。     

Epidemiology of community-acquired Staphylococcus aureus bacteremia.

Methicillin-resistant Staphylococcus aureus (MRSA) is an important nosocomial pathogen which has been isolated with increasing frequency in recent decades. Community-acquired MRSA (CA-MRSA) infections have also become increasingly important in recent years. This study retrospectively analyzed the risk factors, duration of hospitalization, yearly trend and seasonal variation in prevalence, and antibiotic susceptibility of isolates of community-acquired S. aureus (CASA) bacteremia and CA-MRSA bacteremia from patients treated in a teaching hospital in northern Taiwan. A total of 104 clinical isolates of CASA bacteremia were collected between January 1999 and December 2001. Among these, 35 (33.7%) were identified as MRSA. After multivariate analysis, the independent risk factors for developing CA-MRSA bacteremia were diabetes mellitus (p=0.028), chronic obstructive lung disease (p=0.037), and renal insufficiency (p=0.041). Only 6 (17.1%) patients in the MRSA group had no identified risk factors. Most of the isolates of CA-MRSA had a high degree of resistance to most antibiotics, including clindamycin (71.4%), trimethoprim-sulfamethoxazole (65.7%), and chloramphenicol (41.2%). No major trend or seasonal variation in the prevalence was found during the study period. No difference in mortality related to resistance pattern was found. Although CA-MRSA is not the major pathogen in community-acquired bacteremia, it should be included in the differential diagnosis of Gram-positive bacterial bloodstream infection, especially in those patients with risk factors. Early empiric therapy with glycopeptides in these patients may reduce morbidity and mortality.     

Interobserver variability in determining MIB-1 labeling indices in oligodendrogliomas

Several studies have shown that MIB-1 labeling indices correlate well with tumor grade and prognosis in a variety of tumor types. Several factors are responsible for some degree of variability in the determination of labeling indices. Interobserver variability is one of the factors often cited as responsible for this variability. A slide from each of 30 oligodendrogliomas, stained with MIB-1 antibody, was distributed to six pathologists. The same set of slides was reviewed by each individual. Each pathologist was instructed to determine a MIB-1 labeling index by evaluating 1,000 tumor cell nuclei from the area of the slide with the most staining. The labeling index record reflected a percentage of positive-staining tumor cells. Interobserver agreement was compared. MIB-1 labeling indices ranged from 0 to 45.7. Overall agreement was good (> or =0.75) with a concordance coefficient of 0.832 (confidence interval, 0.700 to 0.909). Variability was greater among tumors with higher labeling indices as compared with tumors with labeling indices closer to 0. The overall agreement of MIB-1 labeling indices, while not perfect, was good. The generally minor variability among observers may be related to differences in the area of the slide evaluated and in differing lower thresholds for interpreting positivity. Further improvement of concordance may theoretically be attainable by further training and discussion among observers.     

Clinical features and risk factors for mortality in Aeromonas bacteremic adults with hematologic malignancies.

BACKGROUND AND PURPOSE: Aeromonas spp. often cause infections in immunocompromised patients. To specifically understand the clinical features of Aeromonas bacteremic adults with hematologic malignancies, we investigated the demographic, clinical and microbiologic characteristics of Aeromonas bacteremia in this patient population. METHODS: Retrospective study performed in a tertiary medical center in southern Taiwan, in which adults with hematologic malignancies suffered from Aeromonas bacteremia admitted between 1995 and 2003 were included for study. RESULTS: There were 45 episodes of Aeromonas bacteremia in 41 adults with hematologic malignancies. Episodes of Aeromonas bacteremia which occurred at least 2 months apart were counted as separate cases in the analysis. A total of 30 men and 15 women (mean age: 53.2 years), with 4 patients experiencing 2 episodes, was included. The 3 leading underlying hematologic malignancies were acute myelogenous leukemia (37.8%), myelodysplastic syndrome (26.7%) and non-Hodgkin's lymphoma (17.8%). No cluster of Aeromonas bacteremia was found during the study period. Twenty nine (64.4%) of the 31 patients with nosocomial Aeromonas bacteremia had received recent antineoplastic chemotherapy. The 3 leading clinical manifestations were fever (88.9%), septic shock (40%), and altered consciousness (26.7%). Eleven (24.4%) episodes of bacteremia were polymicrobial. Sixteen (35.6%) patients died within 14 days of onset of bacteremia. The mean duration from sampling blood for culture to death was 3.81 days. Altered consciousness (odds ratio, 8.999; 95% confidence interval, 1.787-45.33; p=0.008) was the only independent prognostic factor for mortality. High resistance rates (11.1% to piperacillin and 35.6% to imipenem) among Aeromonas isolates were also noted. CONCLUSION: In febrile patients with hematologic malignancies and suspected Aeromonas infections, particular attention to the development of alteration of consciousness is needed as it is an independent risk factor for mortality.     

大学生性行为及性道德观发展研究

目的 了解当代大学生性行为及性道德观念的发展变化。方法 自制问卷，对全国9所高校的2000余名大学生进行调查，并用SPSS10．0对结果进行统计处理。结果 大学生性交行为发生率呈逐年上升趋势，且随年级上升而增加；大学生认可性交行为道德观的5个雏度，但各年级之间有差异；大学生边缘性行为和独自性行为发生率随年级显著上升，认可度也随年级增加而上升；大学生对同性性接触基本持排斥态度，但排斥态度则趋于下降。结论 大学生性行为和性道德随年级上升而明显变化，应加强学校教育和引导。     

Remodelling of action potential and intracellular calcium cycling dynamics during subacute myocardial infarction promotes ventricular arrhythmias in Langendorff-perfused rabbit hearts

We hypothesize that remodelling of action potential and intracellular calcium (Ca_i) dynamics in the peri-infarct zone contributes to ventricular arrhythmogenesis in the postmyocardial infarction setting. To test this hypothesis, we performed simultaneous optical mapping of Ca_i and membrane potential ( V _m) in the left ventricle in 15 rabbit hearts with myocardial infarction for 1 week. Ventricular premature beats frequently originated from the peri-infarct zone, and 37% showed elevation of Ca_i prior to V _m depolarization, suggesting reverse excitation–contraction coupling as their aetiology. During electrically induced ventricular fibrillation, the highest dominant frequency was in the peri-infarct zone in 61 of 70 episodes. The site of highest dominant frequency had steeper action potential duration restitution and was more susceptible to pacing-induced Ca_i alternans than sites remote from infarct. Wavebreaks during ventricular fibrillation tended to occur at sites of persistently elevated Ca_i. Infusion of propranolol flattened action potential duration restitution, reduced wavebreaks and converted ventricular fibrillation to ventricular tachycardia. We conclude that in the subacute phase of myocardial infarction, the peri-infarct zone exhibits regions with steep action potential duration restitution slope and unstable Ca_i dynamics. These changes may promote ventricular extrasystoles and increase the incidence of wavebreaks during ventricular fibrillation. Whereas increased tissue heterogeneity after subacute myocardial infarction creates a highly arrhythmogenic substrate, dynamic action potential and Ca_i cycling remodelling also contribute to the initiation and maintenance of ventricular fibrillation in this setting.     

压阻传感器在脉搏信号测试上的应用研究

脉搏是心脏和血管状态重要生理信息的外在反映，作者首先分析了在脉搏测量中传感器和放大电路设计的问题－即脉搏信号的特殊性，然后介绍膜型及囊型两种压力传感器；并给出脉搏信号放大电路。指出测量方法的进一步发展和对临床应用的意义。     

振动减肥中腹壁脂肪的超声检测与力学特征

本文是在研究振动对生物体内物质的耗散作用的基础上，试图利用振动对动物腹壁脂肪进行减脂的探索。通过实验，证实了利用趋声作为手段，可以对动物体内的腹壁脂肪作无创伤活体测量，其误差仅在１０％左右。使用振动对脂肪块得出了疲劳曲线和振动在生物体内传播的衰减曲线。对新鲜离体脂肪块所作振动模拟实验，证明在所使用的频率和振幅的振动作用下，能够迅速使脂肪的厚度消减，根据初步观察，在振动过程中有甘油从脂肪块中溢出，其消减体积的百分之八十为甘油成份，可以认为振动能促使脂肪细胞膜破裂或促使脂肪细胞内的脂滴水解，因此振动有可能成为减肥治疗方案中的一个重要措施。