低剂量率γ射线杀伤肿瘤细胞机制的实验研究

用60Co源以1Gy/min剂量率照射Hela细胞,剂量分别为1、2、5、10、15Gy.用AnnexinV和PI双染法观察凋亡细胞形态;DNA梯形条带证实凋亡存在;克隆形成分析细胞增殖能力.结果显示:(1)Hela细胞凋亡率随照射剂量和时间的增加呈上升趋势,照射后168h组各剂量点凋亡率高于其他各时间组.2Gy以下时凋亡率改变不大,达5Gy时凋亡率显著增加,且达峰值(72.57±2.04)%(P＜0.001).(2)早期凋亡细胞,PS外翻,胞膜呈绿色荧光圈.凋亡晚期出现Annexin V-FITC及PI染色均阳性的外绿内红的细胞图像.坏死细胞则为红色.(3)凋亡细胞碎片呈"梯状"条带.(4)1Gy/min的剂量率照射,剂量为2-15Gy,克隆形成率由(58.95±0.36)%降至(1.67±0.35)%(P＜0.001).表明低剂量率γ射线照射可诱导Hela细胞凋亡,其凋亡率与照射剂量相关,在5Gy时凋亡率最高.     

离子色谱同时测定果汁中22种糖、糖醇和醇

目的建立积分安培-离子色谱法同时测果汁中22种糖、糖醇和醇定的方法。方法在流速为0.40 mL/min, pH值在6.5～8.6,柱温为30℃条件下,在CarboPacTM MA1(4 mm×250 mm)色谱柱中进行分离。结果 22种组分在测定浓度范围内具有良好的线性关系(r~20.999);除了甲醇外,其他21种组分检出限在0.006～0.203 mg/L之间;在0.50、1.00、5.00 mg/L 3个添加浓度水平下,回收率为75.83%～105.89%,相对标准偏差(RSD)在1.03%～10.39%范围内。结论该方法简便、快速、准确、灵敏,完全适于果汁中22种糖、糖醇和醇的分析测定。     

高温SO I CMO S 倒相器瞬态特性的研究

本文主要研究高温SOI CMOS倒相器在（27－300℃）宽温区的瞬态特性。研究结果表明：当采用N^ PN^ 和P^＋PP^ 结构薄膜SOI MOSFET组合，并且其结构参数满足高温应用的要求，则SOI CMOS倒相器实验样品在（27－300℃）具有良好的高温瞬态特性。     

Changes in myocardial hemodynamics and contractile function in patients under surgical treatment for prostatic adenoma

Hemodynamics and left ventricular myocardial contractility in 170 patients who underwent surgery of prostatic adenoma were examined in preoperative period and 16 days after single-stage transvesical adenomectomy. The age of the patients varied from 52 to 85 years. Echocardiography and the dilution method were used for the evaluation. The increase of end-diastolic and end-systolic volumes, stroke volume, cardiac index, was registered. The combined pharmacological treatment made it possible to decrease the number of operative and postoperative cardiovascular complications.     

In vivo characterization of cytotoxic intracellular edema by multicomponent analysis of transverse magnetization decay curves

The precise measurement of low numbers of leukocyte below 0.1 WBC/microliter in filtered red cell or platelet suspensions meet both aims: to check the compliance with previously determined requirements and to evaluate the performances of novel filtering material (5 log depletion or more), justified by more and more important clinical use. The reliability of results, obtained with the chosen method, is ensured by applying of validation protocol, including training of technologist, assessment of the analytical range and the detection limit, assessment of precision and accuracy. The flow cytometry (FC) and Nageotte Chamber (NC) method are the both techniques which are currently used in routine Quality Control (QC) and validated by multicenter studies. Recent developments are made for increasing the sensibility of these counting methods, thanks to higher concentration or volume of the sample to be analysed. Among the experimental techniques, requiring more advances before implementing in QC program, quantitative PCR must become essential as reference method for evaluating the efficiency of filtration, in the future.     

Monoclonal antibodies recognizing epitopes on the extracellular face and intracellular N-terminus of the human erythrocyte anion transporter (band 3) and their application to the analysis of South East Asian ovalocytes

This report describes the production and characterization of 13 rodent monoclonal antibodies to the human erythrocyte anion transport protein AE1 (syn. band 3). Eleven antibodies (4 murine and 7 rat) recognize epitopes dependent on the integrity of the third extracellular loop of the protein. Two antibodies (1 murine and 1 rat) recognize epitopes on the N-terminal cytoplasmic domain. Quantitative binding studies using radioiodinated IgG and Fab fragments of antibodies to extracellular epitopes on AE1 ranged from 77,000 to 313,000 (IgG) and from 241,000 to 772,000 (Fab) molecules bound at saturation. The results indicate that the epitopes recognized by different antibodies vary in their accessibility and suggest that there is heterogeneity in the organization of individual AE1 molecules in the red blood cell membrane. Quantitative binding studies on South East Asian ovalocytes using several antibodies to AE1 and an anti-Wrb show a marked reduction in the number of antibody molecules bound at saturation. These results are consistent with the existence of highly cooperative interactions between transmembrane domains of AE1 in normal erythrocytes and the disruption of these interactions in the variant AE1 found in South East Asian ovalocytes.     

A novel phosphatidylinositol-3,4,5-trisphosphate 5-phosphatase associates with the interleukin-3 receptor

To gain insight into the intracellular signaling cascades that are activated by the binding of interleukin-3 (IL-3) to its target cells, we have embarked on the identification of proteins that are associated with the IL-3 receptor (IL-3R). In a previous study we reported that a 110-kDa serine/threonine protein kinase is constitutively associated with the IL-3R and activated following IL-3 stimulation. We now report that a phosphatidylinositol-3,4, 5-trisphosphate (PtdIns-3,4,5-P3) 5-phosphatase (5-ptase) is also constitutively associated with the IL-3R. This 5-ptase is magnesium-dependent and removes the 5-position phosphate from PtdIns-3,4,5-P3 but does not metabolize PtdIns-4,5-P2, inositol (Ins)-1,3,4,5-P4, or Ins-1,4,5-P3. This substrate specificity distinguishes it from any previously characterized 5-ptase. Interestingly, it may be bound indirectly via phosphatidylinositol 3-kinase (PI 3-kinase), another enzyme that is constitutively bound to the IL-3R. However, unlike PI 3-kinase which becomes activated following IL-3 stimulation, this receptor-associated 5-ptase activity does not increase following IL-3 stimulation, and its primary function may be to keep the principal in vivo product of PI 3-kinase, PtdIns-3,4,5-P3, at low levels in unstimulated cells, to terminate the PI 3-kinase signal following IL-3 stimulation or to metabolize PtdIns-3,4,5-P3 to a metabolically active second messenger, i.e. PtdIns-3,4-P2.     

3,3''-Diindolylmethane induces apoptosis in human cancer cells

Several recent reports presented conflicting data on the action of IL-4 and IL-13 in regulating the release of proinflammatory cytokines by human monocytes. Here we show that the regulation of cytokine release by IL-4 and IL-13 could be either inhibitory or stimulatory in LPS-treated murine peritoneal macrophages. When macrophages were treated with IL-13 or IL-4, between 6 and 24 hr prior to endotoxin challenge, TNF alpha and IL-6 levels were significantly augmented. On the other hand, when the cells were cotreated with LPS plus IL-13 or IL-4, the release of TNF alpha and IL-6 was inhibited. These effects of IL-4 and IL-13 were associated with the modulation of IL-10; pretreatment resulted in a decrease, whereas cotreatment gave rise to a dramatic increase in IL-10 levels. The inhibitory effect of IL-4 and IL-13 on the release of TNF alpha was partially reversed by neutralizing anti-IL10 antibody, and the inhibition of IL-6 release was completely reversed by the antibody. These data suggest that the mechanism of action of IL-13 and IL-4 in modulating macrophage TNF alpha and IL-6 release partially involves IL-10.     

Changing clinical practice. Prospective study of the impact of continuing medical education and quality assurance programs on use of prophylaxis for venous thromboembolism

OBJECTIVE: To determine the effect of continuing medical education (CME) with and without a quality assurance component (CME+QA) on physician practices in the prevention of venous thromboembolism. METHODS: A communitywide study was performed in 15 short-stay hospitals in central Massachusetts. The study population included 3158 patients in acute-care hospitals with multiple risk factors for venous thromboembolism. Study hospitals were randomly assigned to one of two educational strategies or to a control group that received no intervention. RESULTS: The proportion of patients at high risk for venous thromboembolism who received effective methods of prophylaxis increased significantly from 29% in 1986 to 52% in 1989 (P < .001). This increase was seen in all study groups: control hospitals, 40% to 51% (P < .001); CME hospitals, 21% to 49% (P < .0001); and CME+QA hospitals, 27% to 55% (P < .0001). The increase in prophylaxis use from 1986 to 1989 was significantly greater among patients cared for in hospitals whose physicians participated in a formal CME program (an increase of 28%) than in control hospitals (an increase of 11%) (P < .001). There was no significant difference in the use of prophylaxis in hospitals whose physicians received CME+QA interventions compared with hospitals whose physicians received CME interventions alone (identical increases of 28%). CONCLUSION: A formal CME program significantly increased the frequency with which physicians prescribed prophylaxis for venous thromboembolism. We believe the key factor in our CME interventions that motivated clinicians to change their practices was the provision of hospital-specific data demonstrating a compelling need for improvement. Despite the substantial investment by hospitals in QA, traditional QA intervention appeared to provide no additional benefit. Even after extensive CME/QA interventions, prophylaxis for venous thromboembolism remained underutilized, suggesting the need to develop new approaches to changing clinical practice.