总粉尘浓度转换为呼吸性粉尘浓度的两种方法学研究

目的探讨流行病学研究中历史性总粉尘浓度转换成呼吸性粉尘浓度的理论方法。方法采用两种方法：一种通过体积直接计算;另一种用ＨａｔｃｈＣｈｏａｔｅ方程计算,推导出计数百分比和计量百分比的转换关系。结果得到总粉尘浓度与呼吸性粉尘浓度的理论转换系数,其中,用ＨａｔｃｈＣｈｏａｔｅ方程计算结果偏低。结论体积直接计算法更适用。     

Experimental intrahepatic portacaval anastomosis: use of expandable Gianturco stents

Original Gianturco expandable stents and their modifications were used to create an experimental intrahepatic portacaval anastomosis (EIPCA) in 30 young domestic swine without portal hypertension. The study focused on the design of a suitable stent, the technique of its application, and the evaluation of short-term patency of the EIPCA. A stent with a 2.5-cm-long body and wire skirts on both ends was most suitable for EIPCA creation. Well-positioned stents shunted most of the portal blood in the inferior vena cava circulation and remained patent for 4-6 weeks. Ingrowth of liver parenchyma and abundant proliferation of the intima and connective tissue inside the stent lumen in these rapidly growing animals gradually decreased EIPCA patency, and thrombus formation with diminished blood flow closed them completely.     

Renal transplantation in the United Kingdom for patients from ethnic minorities

BACKGROUND: To investigate any differences in access to transplant and post-transplant outcomes for ethnic minority patients in the United Kingdom, national data on ethnicity of patients on the waiting list, those receiving a transplant, and deceased donors were analyzed. METHODS: Adult patients and donors were included. Ethnic origin was classified as white, Asian, black, or "other." National data were analyzed, and 2001 U.K. National census data were used for comparative purposes. Median waiting times to transplant were obtained from Kaplan-Meier estimates for patients registered 1998-2000. Transplant survival was estimated for patients transplanted from 1998 to 2003. RESULTS: A total of 92% of the U.K. population was white, compared with 77% of waiting list patients, 88% of transplant recipients, and 97% of deceased donors. Median waiting time to transplantation for white patients was 719 days (95% confidence interval 680-758) compared with 1368 (1131-1605) days for Asian patients and 1419 (1165-1673) days for black patients. The degree of human leukocyte antigen matching achieved was inferior for Asian and black patients. There is some evidence of inferior 3-year transplant survival for black patients compared with white and Asian patients (P=0.03). CONCLUSIONS: There are imbalances in the ethnic make up of the waiting list, the donor pool, and renal transplant recipients. There are significant differences in both post-transplant outcomes and time to transplantation between patients of different ethnic origin. Waiting times are influenced by allocation schemes, and the 2006 U.K. National Kidney Allocation Scheme is designed to achieve greater equity of access to transplant for all patients, regardless of geography, blood group, or ethnicity.     

整合患者导向的测量工具项目编制等距量表实现ICF类目用于评定的可操作化

目的通过整合不同的患者导向的测量工具的项目来编制ICF特定类目的等距量表结构。方法使用有效的122例类风湿关节炎患者的样本资料进行心理测量研究。患者完成6个不同的以患者导向的测量工具。将这些测量工具项目的内容与ICF类目进行匹配。对项目反应等级进行Rasch分析用于检查这些测量工具项目是否说明了ICF类目b130:能量和驱力功能,从而构成一个心理测量可靠的等距量表。结果 19个项目与b130能量和驱力功能有关。根据2χ检验和Z值统计,19个项目中的16个项目拟合Rasch模型(项目和个人的ZMean=0.451,ZSD=1.085和ZMean=-0.223,ZSD=1.132)。Person分离指数rβ是0.93。结论可以构建ICF类目等距量表使得单个ICF类目可操作化。每个项目的原始格式在等距量表中保持不变。本研究在ICF的操作和将来的实施方面迈出了重要的一步。     

Driving simulator performance in patients with sleep apnea

Although previous studies have shown that patients with obstructive sleep apnea have a higher automobile crash rate than normal subjects, objective measurements of driving performance in patients with sleep apnea have not been reported. Therefore, we compared the driving performance of subjects with untreated, severe sleep apnea to that of control subjects on two driving simulators. Using a simulator with road films, six subjects with untreated, severe apnea performed worse than did a control group of seven normal subjects on both highway and city/rural driving (p less than 0.05). Using a personal computer program simulating a monotonous highway drive, 12 subjects with untreated sleep apnea performed worse than 12 control subjects. The patients with apnea hit a greater number of road obstacles during their 30-minute simulated drive than did the control subjects (44 +/- 52 in patients with apnea versus 9 +/- 7 in control subjects, p less than 0.05). Six patients with apnea hit fewer road obstacles after treatment with nasal continuous positive airway pressure (CPAP) than before treatment (29 +/- 19 before CPAP versus 13 +/- 8 after CPAP, p less than 0.05). We conclude that: (1) driving simulator performance of untreated subjects with severe obstructive sleep apnea is worse than that of control subjects; (2) driving simulator performance of subjects treated with nasal CPAP improves.     

Leptin as regulator of pulmonary immune responses: Involvement in respiratory diseases

Leptin is an adipocyte-derived hormone, recognized as a critical mediator of the balance between food intake and energy expenditure by signalling through its functional receptor (Ob-Rb) in the hypothalamus. Structurally, leptin belongs to the long-chain helical cytokine family, and is now known to have pleiotropic functions in both innate and adaptive immunity. The presence of the functional leptin receptor in the lung together with evidence of increased airspace leptin levels arising during pulmonary inflammation, suggests an important role for leptin in lung development, respiratory immune responses and eventually pathogenesis of inflammatory respiratory diseases. The purpose of this article is to review our current understanding of leptin and its functional role on the different resident cell types of the lung in health as well as in the context of three major respiratory conditions being chronic obstructive pulmonary disease (COPD), asthma, and pneumonia.     

Biochemistry of the induction and prevention of lipoperoxidative damage in human spermatozoa

Lipid peroxidation occurs in human sperm cells with damage to the cell plasma membrane, leading to loss of cytosolic components and hence to cell 'death'. The peroxidation may be induced at high rates in the presence of Fe2+ and ascorbate. It occurs at slower rates under physiological conditions as spontaneous lipid peroxidation, which has the following characteristics. The rate is constant over the time required for complete loss of motility in the cells of the sperm sample; one can thus use the time to complete loss of motility (TLM) as a ready measure of the rate. Loss of motility occurs at a characteristic extent of lipid peroxidation, assayed in terms of production of the peroxidative breakdown product, malonaldehyde (MA), that is independent of peroxidation rate. For human sperm, this extent corresponds to 0.1 nmol MA/10(8) cells. Human spermatozoa possess the anti-lipoperoxidative defence enzymes, superoxide dismutase (SOD) and glutathione peroxidase plus glutathione reductase (GPX/GRD). The SOD activity is highly variable between human sperm samples while the activities of GPX and GRD are rather more constant. The rates of production of superoxide anion, O2-, and hydrogen peroxide, H2O2, from human spermatozoa are variable, but their sum calculated in O2- equivalents as O2- + 2H2O2 is quite constant. The variability arises from the variability in SOD activity: all H2O2 produced is from O2- due to the action of SOD. The essential role of SOD as defence enzyme is inferred from the observation that TLM of a given sperm sample is directly proportional to the SOD activity of that sample. The essential role of GPX/GRD is inferred from the observation that inhibition of GPX, either with mercaptosuccinate or with complete oxidation of intracellular reduced glutathione, results in a 20-fold increase in peroxidation rate. The capacity of the GPX/GRD system appears to be limited by the glucose-6-phosphate dehydrogenase-catalysed rate of production of NADPH, the required reductive substrate for GRD. Human spermatozoa appear to have enough anti-lipoperoxidative defensive capacity for lifetimes long enough for fertilization but still short enough for ready removal from the female reproductive tract in good time. Too low a defence capacity could lead to male infertility.      

Bacterial cultures of the lower respiratory tract in normal volunteers with and without experimental rhinovirus infection using a plugged double catheter system

To test a method of obtaining specimens for microbiologic culture from the lower respiratory tract, we bronchoscoped 25 otherwise normal subjects with and without experimental rhinovirus infections and collected specimens for bacterial culture with a brush housed in a plugged double catheter apparatus. Fifty-two specimens of the lower respiratory tract were obtained from the 25 subjects; nasopharyngeal swabs were also obtained from each subject prior to bronchoscopy. Specimens obtained from the lower respiratory tract were positive for bacteria in 21 (84%) of 25 subjects and at 38 (73%) of 52 sites. The frequency of obtaining positive bacterial cultures was similar in volunteers with (69%) or without (90%) rhinovirus infection. Oropharyngeal contamination of bronchial specimens was minimized by administering atropine and by bronchoscoping subjects in the supine or Trendelenburg position. These data indicate that the plugged double catheter brush system does not consistently yield specimens that are free of bacterial contamination from the oropharynx.