血压自动控制系统应用于抗失血性休克的实验研究

本文设计的８模型血压自适应控制系统，试用于造成失血休克模型的家兔的血压自控治疗，２２只休克家兔中１８只能控制血压于预置水平。根据血压控制期间药物输注速率变化规律，可将２２只家兔分为三类，剂量上升型、剂量下降型和迟钝型。实验表明多模型血压自适应控制系统应用于失血性休克家兔的血压控制治疗是可行的，能做到剂量个体化，按需给药。在血压控制期间显示的药物输注速率变化能在一定程度上反映机体休克状况，有可能为及     

Synthesis and acid ionization constants of cyclic cystine peptides

Cyclic peptide disulfides of the general formula were synthesized from the corresponding peptide derivatives [Boc-Cys(Trt)(Gly)-_n-Cys(Trt)-OBu^t] by oxidation with iodine in methanol and by subsequent removal of the terminal groups with trifluoroacetic acid. Acid ionization constants of the obtained peptides were determined by potentiometric titration in aqueous KCl (0.1 mol/L) medium. All compounds have two dissociable hydrogens, corresponding to carboxyl (pK¹= 2.35–2.84) and to terminal amino group (pK₂= 5.61–6.93); pK₁, values show first an upward and then a downward trend with the increase in ring size; the opposite is true for pK₂, values. These trends could be tentatively attributed to the intramolecular salt bridge (-COO——-NH⁺₃-) formation.     

Automatic analysis of electro-encephalogram sleep spindle frequency throughout the night

A fully automatic method to analyse electro-encephalogram (EEG) sleep spindle frequency evolution during the night was developed and tested. Twenty allnight recordings were studied from ten healthy control subjects and ten sleep apnoea patients. A total of 22 868 spindles were detected. The overall mean spindle frequency was significantly higher in the control subjects than in the apnoea patients (12.5Hz against 11.7Hz, respectively; p<0.004). The proposed method further identified the sleep depth cycles, and the mean spindle frequency was automatically determined inside each sleep depth cycle. In control subjects, the mean spindle frequency increased from 12.0Hz in the first sleep depth cycle to 12.6Hz in the fifth cycle. No such increase was observed in the sleep apnoea patients. This difference in the spindle frequency evolution was statistically significant (p<0.004). The advantage of the method is that no EEG amplitude thresholds are needed.     

白细胞图像自动识别系统的研究

我们所用的图像分割方法是在对图像距离变换的基础上,综合区域和边界方法,充分利用图像中包含的信息,实现白细胞图像的分割。根据细胞的形状、纹理、颜色等的特点选取并测定22个特征值,用统计分类的方法设计分类器。通过对560幅图像共831个细胞的测试表明,此系统的识别正确率为96%,经临床专家评估,本系统运用模式识别技术对外周血中的白细胞图像实现自动识别,具有较好的实用价值。     

Bovine colostrum supplementation does not affect plasma buffer capacity or haemoglobin content in elite female rowers

It has been reported that bovine colostrum (BC) supplementation improves buffer capacity () during exercise, but whether the improvement results from changes in tissue and/or blood buffer systems has not been determined. The purpose of the present study was to examine the effect of supplementation with BC on blood buffer systems. Thirteen elite females rowers were supplemented with 60 g·day^–1 of either BC (n=6) or whey protein (WP, n=7) during 9 weeks of pre-competition training in a randomised, double-blind, placebo-controlled, parallel design. All subjects undertook the study as a group and completed the same training program. Resting haemoglobin (Hb) concentration and plasma buffer capacity (p) (determined by titration with HCl) were measured pre- and post-supplementation. There were no differences in macronutrient intakes (P>0.56) or training volumes (P>0.99) between BC and WP during the study period. There were no differences in Hb [BC 13.28 (0.28) mg·dl^–1, WP 13.70 (0.26) mg·dl^–1; P=0.45] or p [BC 14.8 (1.1) nmol HCl·ml^–1·pH^–1, WP 14.8 (0.5) nmol HCl·ml^–1·pH^–1; P=0.68] between groups at week 0. p increased in both groups during the study period (P<0.001), but the increases were not significantly different between groups (P=0.52). Hb did not change significantly in either group (P=0.35). These data indicate that supplementation with BC does not affect p or Hb. We therefore suggest that adaptations in tissue buffer systems are responsible for the previously reported increases in buffer capacity that result from BC supplementation.     

A simplified method for the preparation of EAC14 intermediate cells using human serum treated with methylprednisolone

The inhibitory effect of methylprednisolone 21-succinate ester (MPS) on the activities of complement components in human serum was studied by incubating human serum with various concentrations of MPS at 37 degrees C for 30 min and then measuring the residual activity of each component in human serum. The formation of EAC1 and EAC14 by C1 and C4 respectively, were only weakly inhibited by MPS at a final concentration of 10 mg/ml. In contrast, the same concentration of MPS completely inhibited the capacity of C2, C3, C5 and C6-9 to induce respective succeeding intermediates. On the basis of these findings a simplified method was devised for the preparation of EAC14 intermediates using human serum pretreated with MPS.     

Evidence of allosteric conformational changes in the antibody constant region upon antigen binding

We have addressed the question of whether antigen binding induces a conformational change in the heavy chain constant (C(H)) domain of antibodies using staphylococcal protein A or streptococcal protein G as probes, since these proteins are known to bind to IgG domains such as C(H)1 and C(H)2-C(H)3 domains. Biosensor assays on interactions between these proteins and mouse IgG specific to (4-hydroxy-3-nitrophenyl)acetyl (NP) or their enzymatic fragments conducted in the presence or absence of the hapten, NP-epsilon-aminocaproic acid (NP-Cap), showed that the binding of IgG to these proteins was inhibited by the binding of NP-Cap. The results of isothermal titration calorimetry also revealed that the association constant for the interaction of protein A with IgG2b decreased by the addition of NP-Cap. These results suggested that antigen binding induced conformational changes in binding sites for protein G or protein A located at C(H)1 and C(H)2-C(H)3 domains, respectively.     

动物实验模型中多极导管心室除颤系统电除颤对心脏功能的影响

评价新型的双极和三极导管自动心室除颤系统电除颤对左心室收缩和舒张功能的影响。动物麻醉后,在X光机指导下,分别在10只犬心脏内装置双极导管自动除颤系统（组Ⅰ）;在10只猪心脏内装置三极导管自动除颤系统（组Ⅱ）;并行电除颤试验。使用食管超声心动图在电除颤前后记录二维、M型和多谱勒超声图像。组I动物接受4次电除颤,电量为64J;组Ⅱ接受平均8次电除颤,电量为210J。结果显示：左室收缩面积分数、左室等容舒张时间和二尖瓣血流E波与A波速度比值以及时间-流速积分比值等反映左室舒缩功能的指标在两组动物除颤后均无显著改变。研究表明：两种经静脉导管自动心室除颤系统中反复低能量心内膜电除颤对左室舒缩功能无明显损伤作用;研究结果为经静脉多极导管自动心室除颤系统在临床的应用和电生理研究提供了可靠的实验数据。     

Automatic analysis of immunocytochemically stained tissue samples

An automatic colour image segmentation and cell counting software system has been developed for immunocytochemical analysis of stained tissue samples. The system was designed to count the total number of positive and negative cells in tissue samples treated with cytokine DNA probes from pigs naturally parasitised with Taenia solium metacestodes, using in situ hybridisation. A reaction index was calculated as the ratio of the number of cells with a positive reaction to the total number of cells (positives plus negatives) for each of five different probes. The objectives of automatic counting were to improve the reproducibility of the analysis and reduce the processing time of large image batches. A fast KNN classifier was used for colour segmentation. Watershed segmentation combined with edge detection was used to isolate individual cells that were then automatically labelled, using the results of the corresponding colour segmented image. Validation was performed on 122 non-training digital images with a total of 1069 positive cells and 1459 negative cells, with the following results: a mean true positive rate of 90.2% for positive cells and a mean true positive rate of 85.4% for negative cells. The corresponding mean false positive rates were 9.6% and 6.6%. The mean reaction index error of the automatic analysis was 5.35%. The processing of each digital image took 10 s on a Pentium IV PC.