生物人工肝支持系统中细胞材料的选择

学术背景:以培养肝细胞为基础的生物人工肝支持系统是治疗肝衰竭和重型肝炎的重要方法之一,装有细胞材料的生物反应器则是其重要组成部分,而理想的生物人工肝细胞材料应具备成熟肝细胞的所有功能。目的:了解近年来国内外有关生物人工肝细胞材料的研究情况和最新进展。检索策略:主要检索1994-01/2007-06美国国立图书馆网站(PUBMED)、国内全文网站康健西文生物医学期刊文献数据库和中文CHKD网站有关生物人工肝细胞材料的文献,主要为英文检索,辅以中文。关键词为人工肝(liver,artificial)和/或肝细胞(Hepatocytes),干细胞(stemcell),肝细胞系(Livercellline)和永生化肝细胞(immortalization hepatocytes)。检索到685篇文献,不采用未发表的文章。经初步筛查,排除研究目的不同及内容重复的文献,详细阅读27篇。文献评价:所选文献主要来源于Hepatology,Journal of Artificial Organs,Gastroen terology,Annals of Surgery,Tissue Engineering,Journalof Hepatology,Biomaterials等著名杂志,主要为论著。资料综合:目前国内外用于生物人工肝的细胞主要有以下几种:①成人肝实质细胞:主要体现在安全性好,细胞生物学功能相同,最大障碍是来源匮乏,活力难以长时间维持。②猪肝细胞:是生物人工肝支持装置中应用最多的细胞材料,目前已进入Ⅱ/Ⅲ期临床研究,但在使用过程中需密切注意免疫反应和内源性反转录病毒感染的问题。③肝细胞株:是重要的生物人工肝细胞材料之一,来源容易。依靠其获得方法不同,可分为肝肿瘤源性、经传代建立以及病毒转染后的细胞株。④肝干细胞:是非常有潜力的细胞材料,可分为肝源性肝干细胞和非肝源性肝干细胞。结论:目前应用于生物人工肝临床研究的肝细胞主要有猪肝细胞和肝肿瘤细胞株,各有优缺点,永生化人肝细胞、肝干细胞等能否应用于临床,仍需深入探究。     

The control chart: an epidemiological tool for public health monitoring

The objective of the authors is to apply the control chart, a statistical method for quality control used in industry, to public health surveillance. A pilot study was conducted during the 1998 World Football Cup (WFC) by 553 sentinel general practitioners (GPs) throughout France. The average number of cases of communicable, environmental and societal diseases relating to mass gatherings, and the total number of referrals to hospital reported daily by a GP, were plotted on a u-chart for each condition monitored. This average was beyond the statistical control limits if it fell outside the 99.7% confidence interval of the baseline incidences estimated before the WFC. Seven hundred and forty data points representing 262 279 medical encounters were plotted. Nineteen points exceeded the statistical control limits. None of these alerts was confirmed for two consecutive days. Control charts ensured that the level of the items chosen for general community health surveillance remained under control.     

Evaluation of activatory and inhibitory natural killer cell receptors in non-segmental vitiligo: a flow cytometric study

Background Recent observations established the role of altered cellular immunity and autoimmune hypothesis in the pathogenesis of vitiligo. There have been several reports discussing T‐cell and natural killer (NK) cell populations, but NK cell receptors were not evaluated in vitiligo. Objective The purpose of this investigation was to assess the role of T and NK cells as well as activatory and inhibitory NK cell receptor alterations in the pathogenesis of vitiligo and whether any aberrations were correlated with clinical findings of the disease. Patients/methods Fifty‐three patients with non‐segmental vitiligo and 45 age‐ and sex‐matched healthy controls were enrolled in the study. The percentages of lymphocytes, granulocytes, monocytes and CD3, CD4, CD8, CD14, CD16, CD56, CD45, CD45RA, CD54RO, CD28, CD80, CD94, CD158a, KIR3DL‐1 receptors as well as CD94, CD158a, KIR3DL‐1 receptors on CD16⁺ cells were detected by using flow cytometry. The patient and control groups were compared in terms of the results of flow cytometric analysis, and the results were assessed regarding the type and activity of vitiligo. Results The percentages of CD16⁺CD56⁺, CD3⁺CD16⁺CD56⁺, CD8⁺ and CD45RO⁺ cells were significantly increased in vitiligo group compared with the controls. No difference was detected between the patients and control groups in percentages of CD3⁺, CD4⁺, CD3^?CD16⁺CD56⁺, CD28⁺, CD45⁺, CD45RA⁺, CD94⁺, CD158a⁺ and KIR3DL‐1⁺ cells. The percentage of CD16⁺CD158a⁺ cells was significantly decreased in a randomized selected group of vitiligo patients. There were no differences in percentage expression of studied cell surface antigens between patients in the active or stable period. CD3⁺ cells were significantly increased in generalized form, and CD45RO⁺ cells were significantly increased in acral/acrofacial form when compared with the other types of vitiligo. Conclusions These results indicate further evidence for T and NK cell abnormalities in non‐segmental vitiligo. The present data show that NK cell activation may be responsible in the pathogenesis of vitiligo in conformity with decreased inhibitory and increased activatory NK cell receptors.     

川藏香茶菜中双聚对映贝壳杉烯的结构鉴定

从川藏香茶菜的干叶和嫩枝中,分离得到了一个对映贝壳杉烯的双聚体,命名为川藏香茶菜戊素,经光谱解析和化学证明确定了其结构为川藏香茶菜甲素的Diels-Alder双聚体。     

Non-invasive positive pressure ventilation in acute respiratory failure: providing competent care

Non-invasive positive pressure ventilation (NPPV) has been used as an alternative strategy to provide ventilatory support for patients with acute respiratory failure. Most studies demonstrate that the use of NPPV in acute respiratory failure results in a reduction in the need for endotracheal intubation and an overall survival advantage. However, current evidence, in the form of randomized controlled trials, suggests that these benefits may be restricted to patients suffering from acute exacerbation of chronic obstructive pulmonary disease (COPD).

The clinical application of NPPV involves the development of competence in delivering the particular intervention. Clinical outcomes and thus valid comparisons with alternate methods of ventilatory support can only be made if attention is paid to the clinical indications for the application of NPPV and patient subgroups it is used to treat and the level of competence of care givers in its application and delivery. One essential element of competence is the establishment of an appropriate knowledge base and the development of clinical practice guidelines. This literature review identifies the current indications for NPPV and the relevant information for developing clinical practice guidelines for the management of this form of ventilatory support.     

Sunlight Exposure and Breast Density: A Population-Based Study

Purpose

This study aims to assess the association of sunlight exposure with breast cancer risk, measured by the breast density assessed from Tabár''s mammographic pattern in Chinese women.

Methods

A total of 676 premenopausal women were recruited to participate in this study, in which 650 completed a validated sunlight exposure questionnaire via telephone. The mammograms were classified according to Tabár''s classification for parenchyma, and patterns IV & V and I, II & III indicated respectively high and low risk mammographic patterns for breast cancer. The odds ratios (OR) and 95% confidence intervals (CIs) for sun exposure-related variables were estimated using unconditional logistic regression with adjustment for potential confounders.

Results

Among 646 participants, women with high breast cancer risk (Tabár''s patterns IV &V) had less hours spent in the sun than those with low risk (I, II & III) at any age stage. A higher level of sunlight exposure was associated with a significantly lower risk having high risk Tabár''s pattern. Women aged 40 to 44 years who were in the highest tertile of lifetime total hours spent in the sun had a multi-adjusted OR of 0.41 (95% CI, 0.18-0.92; p for trend=0.03) compared with those in the lowest tertile (>2.19 hr/day vs. <1.32 hr/day). For hours spent in the sun across the ages of 6 to 12 years, the comparable OR was 0.37 (95% CI, 0.15-0.91; p for trend=0.03).

Conclusion

These findings suggest that higher sunlight exposure is related to a lower risk of having high risk breast density pattern in premenopausal women. Our results also suggest the most relevant period of exposure is during earlier life.