脉冲多普勒超声定量检测狭窄管流中流动指标的方法学探讨

目的　探讨狭窄管流中一系列流动指标的定量检测方法 ,包括 Reynolds数、相对频带展宽度(RSB)、层流剪应力、法向雷诺应力 (RNS)等。方法　采用临床使用的脉冲多普勒血流仪在狭窄前后多个位点进行多时点检测 ,得出流场特征 ,再分别评价各项指标。结果　定性评价见狭窄下游呈现鲜亮的“烛焰形”花色镶嵌湍流流型 ,狭窄后 1.0 cm处得到较大的 RSB、RNS等 ,1/ 2 R取样容积处湍流指标大于相应的轴心处。结论　狭窄后1.0 cm1/ 2 R取样容积处存在最大的湍流度 ;狭窄后各位点的数据离散度大于狭窄前。该研究为进一步在不同流场中开展生物力学的在体研究奠定了前期工作基础     

流动腔系统的研究进展

流动腔装置广泛用于体外研究流动环境中的细胞力学行为,是研究细胞粘附及应力与生长关系特性的主要手段之一。作者从流动腔系统的分类、数值模拟(包括后向台阶的流动腔数值模拟)、系统构建等三个方面对流动腔系统作一综述。     

Intracellular production of IL-2, IL-4 and IFN-γ by peripheral blood CD3+ cells in intermittent allergic rhinitis

Background: Allergic inflammation is mainly driven by type 2 T helper cells. The aim was to assess the changes in production of type 1 and 2 cytokines by CD3⁺ T cells dependent on natural exposure to allergens in subjects with intermittent allergic rhinitis (IAR) and in non-atopic subjects.Material: A total of 13 patients with IAR and 13 healthy non-atopics were recruited into the study. 11 patients with IAR were examined during the grass pollen season and 11 patients outside the season, 9 of them were assessed on both occasions.Methods: A flow cytometric assessment of intracellular expression of IL-2, IL-4 and IFN- by CD3⁺ cells was performed. For statistical analysis non-parametric tests were used.Results: A tendency to decreased production of IL-4 outside the season was observed (6.94% [3.42–13.33] in season vs. 2.06% [0.7–3.6] out of season). The production of IL-4 was higher in the rhinitic group in the season than in the control group (1.93% [1.07–4.97], p = 0.0034) and production of IL-2 was higher both in and outside the season (9.1% [3.94–15.09] and 10.0% [4.79–25.35] vs. 3.64% (2.64–5.03), p = 0.037 and 0.045, respectively). IL-4/IL-2 and IL-4/IFN- ratios were higher in the IAR group in the season than outside the season.Conclusion: A tendency towards a switch from a predominant type 2 response during natural allergen exposure to its suppression outside the season was found, together with a stable type 1 response.Received 22 July 2004; returned for revision 27 August 2004; accepted by M. J. Parnham 2 November 2004     

A mammalian model of optic-flow utilization in the control of locomotion

Summary Gibson (1966, 1979) and Lee (1976) have described the potential usefulness of optic-flow information for the control of locomotion. One variable that might be particularly important for an animal approaching a target is time-to-collision, which Lee argues is most efficiently specified by the tau margin (the inverse of the relative rate of expansion of the target image on the retina). In humans, most empirical studies of optic flow have required perceptual judgements or have examined catching/intercepting behaviours. In animals, most studies have been strictly observational. This is particularly true for mammals, where there has been no experimental work of any kind looking at the control of locomotion. The present experiment demonstrates that the Mongolian gerbil (Meriones unguiculatus) uses time-to-collision information to control deceleration as it runs towards a target. The development of this animal model will aid investigation of the neural circuitry underlying optic flow utilization in motor control.     

Dysregulation of blood lymphocyte subsets and natural killer cells in schistosomal liver cirrhosis and hepatocellular carcinoma

Immunological factors are important in the pathogenesis of a wide spectrum of hepatobiliary diseases. Using flow cytometry, we determined the changes in lymphocyte subsets and natural killer cells in 123 individuals (81 patients with liver disease and 42 healthy volunteers). The liver diseases included periportal fibrosis (PPF, 10 patients), liver cirrhosis (LC, 31 patients), and hepatocellular carcinoma (HCC, 40 patients). Schistosomiasis and viral hepatitis B and C were the putative etiological agents of liver diseases. Immunophenotyping by indirect immunofluorescence was conducted using monoclonal antibodies to CD3 (T-lymphocytes), CD4 (helper/inducer T-cells), CD8 (suppressor/cytotoxic T-cells), and CD57 (natural killer cells) cell surface markers. Immunophenotyping of PPF patients showed no significant changes in all markers compared with the healthy controls. However, there was a significant decrease ( P<0.01) in CD3 and CD4 T-cells, and a highly significant increase ( P<0.001) in CD57 T-cells in patients with LC or HCC. In addition, LC and HCC patients showed no significant change in CD8 T-cells compared with controls. In conclusion, the progression of liver diseases is associated with a dysregulation of cellular immune responses. T-lymphocytes and natural killer cells may play a role in the immunopathogenesis of liver cirrhosis and HCC.     

流式细胞仪检测尖锐湿疣患者的T细胞亚群及NK细胞

目的 研究尖锐湿疣患者的细胞免疫功能。方法 用流式细胞仪检测了３０例尖锐湿疣患者外周血Ｔ细胞亚群及ＮＫ细胞百分率。结果 尖锐湿疣患者ＣＤ４细胞百分率下降,ＣＤ８细胞百分率增高,ＮＫ细胞数降低,与对照组相比差异均有显著性。结论 尖锐湿疣患者存在细胞免疫功能缺陷。     

大肠腺癌DNA和RNA测定与转移及预后的关系

探讨大肠腺癌DNA和RNA含量的变化意义及预后的关系。方法 :对我院 1985年～ 1992年收治的术后随访 74例病人的大肠腺癌石腊标本重新切片 ,用流式细胞技术进行DNA和RNA含量测定 ,探讨其变化意义与转移预后的关系。结果 :大肠腺癌DNA异倍体与组织学类型无关 ,RNA含量与组织学类型关系密切。DNA异倍体和RNA含量大肠腺癌的Dukes’分期、淋巴结转移、其它脏器转移和根治术后复发均有关。术后生存 5年以上病人的DNA异倍体出现率和RNA含量较术后 1年内死亡病人为低 ,两者有显著性差异 (P <0 .0 1)。结论 :DNA和RNA含量测定可作为判断大肠腺癌的恶性程度、估价预后的客观可靠指标。     

探讨彩色多普勒超声对乳腺肿块的诊断

本文对４０例乳腺肿块患者进行彩色多普勒超声检查,旨在探讨彩色多普勒超声也腺肿块的诊断价值。方法经彩色多普勒检查,观察灶内部及周边血流情况,根据血流丰富程度分成四个等级。结果：发现血流丰富程度与乳腺肿块的良恶性及肿块大小密切相关。     

Periventricular- intraventricular hemorrhage in the premature infant- A historical perspective

The objective of this chapter is to trace the evolution of intraventricular hemorrhage in the premature infant highlighting the importance of the germinal matrix, a critical role for cerebral blood flow changes in the genesis of hemorrhage, clinical factors that increase the bleeding risk, and potential preventative strategies. In 1976, neuropathological studies demonstrated capillary rupture within the germinal matrix as the precursor of hemorrhage. In 1980, introduction of cranial ultrasound facilitated diagnosis of intraventricular hemorrhage. In 1979, loss of cerebral autoregulation in sick newborn infants was demonstrated. In the 1980’s, studies demonstrated the importance of intravascular factors in provoking hemorrhage. In 1983, the association of cerebral blood flow velocity fluctuations and subsequent hemorrhage was demonstrated. In 1994, antenatal steroids use to accelerate lung development was recommended. This was associated with an unanticipated reduction in hemorrhage. In the mid 1990’s early indomethacin administration was associated with a reduction of severe hemorrhage.