不同孔径纳米羟基磷灰石人工骨修复兔桡骨缺损效果比较

目的:纳米级的羟基磷灰石材料与人体内组织成分更为相似,具有更佳的生物性能。评价不同孔径的多孔纳米羟基磷灰石人工骨的骨缺损修复能力,从而筛选出适合的孔径以达到骨传导功能与生物力学性能的良好统一。方法:实验于2005-10/2006-10在深圳市第二人民医院中心实验室完成。①实验材料:纳米羟基磷灰石人工骨以硝酸钙和磷酸二氢铵为原料,采用溶胶-絮凝法制备粉体,运用压力成型、木模成型和浸渍成型分别制得孔隙分布均匀的孔径分别为50～150μm、100～250μm和300～500μm的多孔纳米羟基磷灰石人工骨。②实验动物:雄性新西兰大白兔60只随机分为植入50～150μm孔径材料组、植入100～250μm孔径材料组、植入300～500μm孔径材料组、空白对照组,每组15只。实验过程中对动物处置符合动物伦理学要求。③实验方法:制备双侧桡骨骨缺损动物模型,然后用3种不同孔径的纳米羟基磷灰石人工骨材料植入骨缺损处进行修复,空白对照组不植入任何材料。④实验评估:术后4,8和12周分别行大体标本观察、X射线片观察、扫描电镜观察及生物力学测试,比较各组材料修复骨缺损的能力。结果:实验动物均进入结果分析。①X射线片检查结果:术后4周、8周、12周,植入100～250μm孔径材料组X射线评分高于植入50～150μm,300～500μm孔径材料组,差异有显著性意义(P<0.05)。②生物力学检测结果:术后4周、8周、12周,植入100～250μm孔径材料组生物力学强度高于植入50～150μm,300～500μm孔径材料组,差异有显著性意义(P<0.05)。③扫描电镜观察结果:植入100～250μm孔径材料组成骨效果明显优于植入50～150μm,300～500μm孔径材料组和空白对照组。结论:纳米羟基磷灰石人工骨具有良好的成骨能力,但其骨修复能力受孔径因素的影响,孔径100～250μm的纳米羟基磷灰石人工骨材料成骨能力较好。     

工程化视知觉感知学习系统治疗儿童弱视的效果评价

目的:传统治疗弱视的方法(如遮盖治疗,精细训练等)起效慢,疗效欠佳;视知觉感知学习系统作为一种针对性很强的儿童弱视治疗方法,其疗效需进一步观察。方法:①收集2006-09/2007-02于广西壮族自治区人民医院视光中心就诊的弱视儿童125例250眼,女73例,男52例,年龄(6±2)岁。患儿家长知情同意并签署知情同意书;实验经医院伦理委员会批准。②根据视功能检查结果,采用视知觉感知学习系统对弱视患儿进行针对性的治疗,如双眼视力相差两行以上,辅助遮盖优势眼治疗。1个月为1个疗程,每天训练2次,每次2个训练内容(程序),每个训练内容10min,40min/d,训练内容之间要求有10min左右的休息间隙。训练需在安静和黯淡环境下进行。每月定期复查双眼视力及其各项视功能的恢复情况,并根据复查结果继续原程序治疗或调整治疗程序。结果:弱视患儿125例均进入结果分析。①视力:视知觉感知学习系统治疗儿童弱视的总有效率为75.2%,视力提高行数从治疗第3个月起有大幅增加(P<0.05),最佳矫正视力由治疗前的0.60±0.23提高至治疗后的0.86±0.26,差异有显著性意义(P<0.05)。②治疗时间与疗效:疗效达到进步的平均时间为(2.82±1.30)个月,达到基本治愈为(2.87±1.40)个月。治疗3个月的患者视力疗效达进步率最高[98%(39/40)],治疗1个月的患者视力进步率最低[55%(31/56),P<0.05]。基本治愈率随治疗时间的增加递增,治疗4个月组基本治愈率最高[67%(31/46),P<0.05]。结论:视知觉感知学习系统治疗儿童弱视疗效快,达到有效的时间为治疗两三个月。     

颈动脉内中膜厚度与初诊2型糖尿病视网膜病变的关系

目的:研究发现,糖尿病视网膜病变和动脉粥样硬化终点事件相关。试验拟验证颈动脉内中膜厚度与初诊汉族2型糖尿病患者糖尿病视网膜病变相关危险因素的关系。方法:①试验对象:选择2006-06/2007-06本院住院的初诊2型糖尿病患者187例,男114例,女73例;平均年龄(51±14)岁;平均体质量指数(24.7±4.7)kg/m2。均符合1997年美国糖尿病协会的2型糖尿病诊断标准,排除既往已存在心血管疾病者。患者对治疗及试验均知情同意。根据眼底照相检查结果,将所有受检者分为糖尿病视网膜病变组及非糖尿病视网膜病变组进行统计分析。②试验方法及评估:所有患者询问一般情况,测量颈动脉内中膜厚度以及相关生化指标,对糖尿病视网膜病变相关因素进行单因素及多因素Logistic回归分析。结果:纳入2型糖尿病患者187例,均进入结果分析。单因素Logistic回归分析显示,高血压、糖尿病家族史、颈动脉内中膜厚度、尿白蛋白、低密度脂蛋白胆固醇与糖尿病视网膜病变发生呈显著正相关,多因素Logistic回归分析未见显效因素。结论:单因素回归分析中颈动脉内中膜厚度及其他4项指标与糖尿病视网膜病变相关,而多因素回归分析这些因素未进入主效基因模型。     

Severe road traffic injuries in Kenya, quality of care and access

Background

Road traffic injuries (RTI) are on increase in developing countries. Health care facilities are poorly equipped to provide the needed services.

Objective

Determine access and quality of care for RTI casualties in Kenya.

Design

Cross-sectional survey

Setting

53 large and medium size private, faith-based and public hospitals.

Participants

In-patient road traffic crash casualties and health personnel in the selected hospitals were interviewed on availability of emergency care and resources. Onsite verification of status was undertaken.

Results

Out of 310 RTI casualties interviewed, 72.3%, 15.6% and 12.2% were in public, faith-based and private hospitals, respectively. Peak age of the injured was 15–49 years. First aid was availed to 16.0% of casualties. Unknown persons transported 76.5% of the injured. Police and ambulance vehicles transported 6.1% and 1.4%, respectively. 51.9% reached health facilities within 30 minutes of crash and medical care provided to 66.2% within one hour. 40.8% of recipient facilities were adequately prepared for RTI emergencies.

Conclusions

Most RTI casualties were young and from poor backgrounds. Training of motorists and general public in first aid should be considered in RTI control initiatives. Availability of basic trauma care medical supplies in public health facilities was highly deficient.     

Effectiveness of maternity support belts in reducing low back pain during pregnancy: a review

Aims. This article aims to review the literature published to date on the types, current use, the biomechanical effects and adverse effects of maternity support belts for low back pain during pregnancy, to identify future research directions. Background. Lumbar/pelvic support belts are frequently recommended for the prevention and treatment of low back pain during pregnancy. Design. Systematic review. Methods. MEDLINE, CINAHL, the Cochrane Library and patents databases were electronically searched. Results. Maternity support belts belong to one of the four main types of maternity support garments, which are widely commercially‐available. Current research showed limited evidence in support of the commercial maternity products regarding the effectiveness in the prevention and/or treatment of low back pain during pregnancy, other than that from the manufacturers. However, potential stabilisation effect of maternity support belt was demonstrated in some studies. Adverse effects reported include increased pain, fetal heart rate changes, skin irritation and discomfort. Conclusions. There is insufficient scientific evidence to conclude that wearing maternity support belts reduces pregnancy‐related low back pain and/or pelvic girdle pain. Future research directions in the area of biomechanics and physiology are recommended. Relevance to clinical practice. This review provides comprehensive understanding of the effectiveness of maternity support belts for the relief of low back pain during pregnancy which will facilitate healthcare professionals in providing evidence‐based advice to their patients.     

Direct demonstration that autologous bone marrow transplantation for solid tumors can return a multiplicity of tumorigenic cells

Patients with solid tumors are increasingly being treated by autologous bone marrow transplantation (BMT). Although response rates appear to be increased, disease recurrence is the commonest cause of treatment failure. Whether relapse is entirely due to residual disease in the patient or arises also from infiltrating malignant cells contained in the autologous marrow transplant has not been resolved. If the latter explanation is correct, then purging would be required as part of the transplantation procedure. We used retrovirally mediated transfer of the neomycin-resistance gene to mark BM harvested from eight patients with neuroblastoma in clinical remission. The marked marrow cells were subsequently reinfused as part of an autologous BMT. At relapse, we sought the marker gene in malignant cell populations. Three patients have relapsed, and in each the marker gene was detected by phenotypic and genetic analyses of resurgent malignant cells at medullary and extramedullary sites. Analysis of neuroblast DNA for discrete marker gene integration sites suggested that at least 200 malignant cells, each capable of tumor formation, were introduced with the autologous marrow transplant and contributed to relapse. Thus, autologous BMTs administered to patients with this solid tumor may contain a multiplicity of malignant cells that subsequently contribute to relapse. The marker-gene technique we describe should permit evaluation of the mechanisms of relapse and the efficacy of purging in patients receiving autologous marrow transplantation for other solid tumors that infiltrate the marrow.     

Separation and analysis of subcellular organelles in a human promyelocytic leukemia cell line, HL-60: application to the study of myeloid lysosomal enzyme synthesis and processing

We describe a system for analysis of the intracellular pathways in the biosynthesis and packaging of functionally important proteins in human myeloid cells. The human promyelocytic cell line HL-60 was used since peripheral blood neutrophils are terminally differentiated and do not actively synthesize protein. Cells were disrupted by nitrogen cavitation and subcellular organelles in postnuclear supernatant separated on a discontinuous gradient of Percoll modified to resolve organelles important in protein synthesis. This Percoll gradient separated azurophilic granules from less dense organelles and partially separated the less dense organelles from one another. Approximate densities of organelles identified by electron microscopy and by biochemical markers are azurophilic granules, 1.102 g/mL; endoplasmic reticulum, 1.039 g/mL; Golgi apparatus, 1.032 g/mL; and plasma membrane, 1.027 g/mL. We validated the utility of this method of subcellular fractionation by examining intracellular transport of myeloperoxidase, a myeloid lysosomal enzyme present in azurophilic granules. The subunits of mature myeloperoxidase (molecular weight [mol wt] = 59,000 and 13,500) cosediment with biochemical markers for lysosomes, whereas the large-mol wt (89,000) precursor forms cosediments with biochemical markers of less dense organelles. Within the limits of assay sensitivity, the 89,000-mol wt precursor is enzymatically inactive and has no spectral evidence for a heme group, suggesting that precursors of myeloperoxidase may undergo proteolytic maturation in a prelysosomal compartment with concomitant incorporation of a heme group and acquisition of enzymatic activity. This system of analysis should be suitable for the identification, subcellular localization, and maturational analysis of other myeloid lysosomal enzymes as well as functionally important membrane proteins.     

Fodrin and band 4.1 in a plasma membrane-associated fraction of human neutrophils

Erythrocytes possess a well-characterized submembranous filamentous network which interacts with transmembrane glycoproteins and is composed primarily of spectrin, ankyrin, band 4.1, and short actin filaments. An analogous structure was recently described in platelets. Human polymorphonuclear leukocytes (PMNs) were examined for the presence and plasma membrane association of similar proteins. Isolated PMNs, free of contamination with erythrocytes or platelets, were disrupted by nitrogen cavitation and separated into subcellular organelles on a discontinuous Percoll gradient. Detergent lysates of plasma membrane vesicles, but not azurophilic or specific granules, contained insoluble actin filaments and associated proteins. Immunoblots of detergent-insoluble plasma membrane fractions contained proteins recognized by antibodies to brain fodrin and erythrocyte band 4.1, whereas blots probed with antibodies to erythrocyte spectrin and ankyrin were negative. Fodrin and band 4.1 were not detected in granule fractions, but some fodrin was present in the cytosol. The association of proteins related to fodrin and band 4.1 with the plasma membrane suggests that PMNs contain a submembranous skeleton structurally analogous to that of erythrocytes and platelets. The specific function of these proteins and their structural organization in human PMNs await further study.