重度烧伤患者中心静脉导管感染的原因分析及预防措施

目的探讨烧伤患者中心静脉导管感染的原因并制定有效预防措施。方法对2004年1月～2007年12月烧伤病房158例中心静脉置管患者进行监测，包括导管留置时间、置管部位、穿刺部位皮肤、置管环境及导管的病原学检查结果等。结果引起重度烧伤患者中心静脉导管感染的病原菌中，主要为真菌和表皮葡萄球菌；中心静脉置管感染与导管留置部位、留置时间等原因有关。结论严格遵守无菌操作原则，提高穿刺人员的操作技能，缩短置管时间，并保证置管环境的洁净，是预防中心静脉导管感染的有效措施。     

流感病毒免疫防御机制研究进展

流感病毒感染引起免疫损伤的同时可以激发机体产生免疫应答,在病毒的清除与疾病的恢复及再次感染过程中发挥着有效的防御作用.尽管流感病毒经常发生变异,但自然感染诱导的免疫防御机制仍可提供一定程度的交叉保护作用.这一系列免疫应答的激发及形成包括多种分子及细胞的参与,其发生、发展及转归直接决定着疾病的严重程度及免疫预防的有效性.了解天然免疫应答、粘膜免疫应答及获得性免疫应答的激发与维持可为流感病毒的防治及疫苗的研制提供思路.     

Novel missense mutations in the human lysosomal sialidase gene in sialidosis patients and prediction of structural alterations of mutant enzymes

Three novel missense mutations in the human lysosomal sialidase gene causing amino acid substitutions (P80L, W240R, and P316S) in the coding region were identified in two Japanese sialidosis patients. One patient with a severe, congenital form of type 2 sialidosis was a compound heterozygote for 239C-to-T (P80L) and 718T-to-C (W240R). The other patient with a mild juvenile-onset phenotype (type 1) was a homozygote for the base substitution of 946C-to-T (P316S). None of these mutant cDNA products showed enzymatic activity toward an artificial substrate when coexpressed in galactosialidosis fibroblastic cells together with protective protein/cathepsin A (PPCA). All mutants showed a reticular immunofluorescence distribution when coexpressed with the PPCA gene in COS-1 cells, suggesting that the gene products were retained in the endoplasmic reticulum/Golgi area or rapidly degraded in the lysosomes. Homology modeling of the structural changes introduced by the mutations predicted that the P80L and P316S transversions cause large conformational changes including the active site residues responsible for binding the sialic acid carboxylate group. The W240R substitution was deduced to influence the molecular surface structure of a limited region of the constructed models, which was also influenced by previously identified V217M and G243R transversions. Received: Stptember 21, 2001 / Accepted: November 2, 2001     

Preventive Measures in Mite Asthma

To evaluate the effect of preventive measures 46 patients, all allergic to house-dust mites (Dermatophagoides spp.), were randomly allocated to a study and a control group. According to the patients' subjective recordings of symptom score and use of medicine, compared with the control group, the study group had improved. There was, however, no improvement when comparing the objective recordings of morning and evening peak flow and use of medicine, and it is concluded that the preventive measures in this programme are not very effective for patients allergic to house-dust mites. The reduction in indoor humidity in the study group was limited and, as a high indoor humidity is the cause of huge populations of house-dust mites in homes, it is emphasized that future programmes of preventive measures should focus more on damp problems, particularly those related to bad housing construction.     

流感病毒免疫防御机制研究进展

流感病毒感染引起免疫损伤的同时可以激发机体产生免疫应答,在病毒的清除与疾病的恢复及再次感染过程中发挥着有效的防御作用.尽管流感病毒经常发生变异,但自然感染诱导的免疫防御机制仍可提供一定程度的交叉保护作用.这一系列免疫应答的激发及形成包括多种分子及细胞的参与,其发生、发展及转归直接决定着疾病的严重程度及免疫预防的有效性.了解天然免疫应答、粘膜免疫应答及获得性免疫应答的激发与维持可为流感病毒的防治及疫苗的研制提供思路.     

Psychophysiological Predictors of Attentional Dysfunction in Children with Congenital Heart Defects

Cardiac responses to non-signal stimuli and to signal stimuli in a vigilance task were examined in children born with congenital heart defects (CHD), and in normal and attention deficit disordered (ADD) subjects. Overall task performance was lower in subjects with heart defects and in the ADD group. Cardiac measures revealed that normal children displayed significantly larger heart rate deceleration to the target stimuli than did either of the clinical groups. Moreover, although no group differences were observed in the cardiac response to non-signal auditory stimuli, exaggerated heart rate deceleration was observed to vibrotactile stimuli in both the clinical groups. Regression analyses revealed that the magnitude of the cardiac response to somatosensory stimuli was predictive of task performance (both within and between subject groups), with larger responses associated with higher error rates and lower perceptual sensitivity. Results were suggestive of a predictive relationship between somatosensory reactivity and neuropsychological maturation.     

Differences in maintenance of CD8+ and CD4+ bacteria-specific effector-memory T cell populations

Our knowledge about the kinetics and dynamics of complex pathogen-specific CD8(+) T cell responses and the in vivo development of CD8(+) memory T cells has increased substantially over the past years; in comparison, relatively little is known about the CD4(+) T cell compartment. We monitored and directly compared the phenotypical changes of pathogen (Listeria monocytogenes)-specific CD8(+) and CD4(+) T cell responses under conditions leading to effective and long-lasting protective immunity. We found that the general kinetics of bacteria-specific CD8(+) and CD4(+) T cells during the effector and post-effector phases are synchronized. However, later during the memory phase, CD8(+) and CD4(+) T cell populations differ substantially. Whereas CD8(+) memory T cell populations with immediate effector function are readily detectable in lymphoid and non-lymphoid tissues and remain remarkably stable in size, antigen-specific CD4(+) effector-memory T cells decline continuously in frequency over time. These findings have important implications for the better understanding of the in vivo development of protective immunity towards intracellular pathogens.     

Skin Conductance Conditioning to Potentially Phobic Stimuli as a Function of Interstimulus Interval and Delay Versus Trace Paradigm

Because prepared learning has been defined in terms of response acquisition in spite of degraded input, it was expected that differences in resistance to extinction between skin conductance responses conditioned to potentially phobic and neutral stimuli would increase with increased interstimulus interval (ISI) and be larger with a trace than with a delay conditioning paradigm. Twelve groups with 10 subjects each were observed in a differential conditioning experiment manipulating ISI (2, 8, or 16 sec), paradigm (delay versus trace), and fear-relevance of the conditioned stimulus (potentially phobic versus neutral). The results showed highly reliable resistance to extinction of first-interval anticipatory responses to phobic stimuli, and no resistance to extinction of the corresponding responses to the neutral stimuli. This difference did not interact either with the ISI or the paradigm factor. Thus, although underscoring the reliability of the difference in conditioning to potentially phobic and neutral stimuli, the results did not support the specific hypothesis of conditioning to phobic stimuli as being less dependent on the ISI parameters than conditioning to neutral stimuli.     

Simulation Studies of Latency Measures of Components of the Event-Related Brain Potential

We compared the accuracy of P300 latency estimates obtained with different procedures under several simulated signal and noise conditions. Both preparatory and signal detection techniques were used. Preparatory techniques included frequency filters and spatial filters (single electrode selection and Vector filter). Signal detection techniques included peak-picking, cross-correlation, and Woody filter. Accuracy in the latency estimation increased exponentially as a function of the signal-to-noise ratio. Both Woody filter and cross-correlation provided better estimates than peak-picking, although this advantage was reduced by frequency filtering. For all signal detection techniques, Vector filter provided better estimates than single electrode selection. Large component overlap impaired the accuracy of the estimates obtained with both single electrode selection and Vector filter, but with Vector filter impairment occurred only when the overlapping component had a scalp distribution that was similar to the scalp distribution of the signal component. The effects of varying noise characteristics, P300 duration and latency, and the parameters of Vector filter were also investigated.     

HCV高变区合成多肽的抗原性研究

目的：通过计算机同源模建，寻找丙型肝炎病毒高变区（HCV HVR1）中保护性多肽抗原表位。方法：计算机同源模建，预测多肽的抗原性，然后用淋巴细胞转化的方法验证其抗原性，结果：同源模建与实验结果一致，多肽抗原性有待进一步的提高。结论：同源模建是一种高效寻找具有保护性抗原多肽的经济快速方法。