Effect of ketamine on apoptosis by energy deprivation in astroglioma cells using flow cytometry system

Apoptosis is a programmed, physiologic mode of cell death that plays an important role in tissue homeostasis. As for the central nervous system, ischemic insults can induce pathophysiologic cascade of apoptosis in neurophils. Impairment of astrocyte functions during brain ischemia can critically influence neuron survival by neuronglia interactions. We aimed to elucidate the protective effect of ketamine on apoptosis by energy deprivation in astrocytes. Ischemic insults was induced with iodoacetate/ carbonylcyanide m-chlorophenylhydrazone (IAA/CCCP) 1.5 mM/20 microm or 150 microm/2 microm for 1 hr in the HTB-15 and CRL-1690 astrocytoma cells. Then these cells were reperfused with normal media or ketamine (0.1 mM) containing media for 1 hr or 24 hr. FITC-annexin-V staining and propidium iodide binding were determined by using flow cytometry. Cell size and granularity were measured by forward and side light scattering properties of flow cytometry system, respectively. An addition of ketamine during reperfusion increased the proportion of viable cells. Ketamine alleviated cell shrinkage and increased granularity during the early period, and ameliorated cell swelling during the late reperfusion period. Ketamine may have a valuable effect on amelioration of early and late apoptosis in the astrocytoma cells, even though the exact mechanism remains to be verified.     

布氏显微镜活血分析: 细胞流变学研究的新方法

布氏显微镜活血分析：细胞流变学研究的新方法骆秉铨＊黄荣国＊陈兴新＊细胞流变学是研究血细胞流动变形的科学，在方法学上发展了一些比较成熟的方法，但多不能直接动态观察细胞水平的真实改变，有待完善和创新。我们采用布氏多功能显微镜的活血分析法［１］，在高放大倍...     

Contributions of the ubiquitin–proteasome pathway and apoptosis to human skeletal muscle wasting with age

The primary mechanism that contributes to decreasing skeletal muscle strength and size with healthy aging is not presently known. This study examined the contribution of the ubiquitin–proteasome pathway and apoptosis to skeletal muscle wasting in older adults (n = 21; mean age = 72.76 ± 8.31 years) and young controls (n = 21; mean age = 21.48 ± 2.93 years). Subjects underwent a percutaneous muscle biopsy of the vastus lateralis to determine: (1) ubiquitin ligase gene expression (MAFbx and MuRF1); (2) frequency of apoptosis; and (3) individual fiber type and cross-sectional area. In addition, a whole muscle strength test was also performed. A one-way ANOVA revealed significant increases in the number of positive TUNEL cells in older adults (87%; p < 0.05), although no significant increase in caspase-3/7 activity was detected. Additionally, ubiquitin ligase gene expression, individual muscle fiber type and CSA were not different between old and young subjects. Muscle strength was also significantly lower in old compared to young subjects (p < 0.05). In conclusion, this study indicates a preferential role for apoptosis contributing to decreases in muscle function with age.     

低营养及低氧状态下NIH3T3细胞增殖及细胞周期的变化及对bFGF的影响

目的： 体外模拟慢性创面缺氧、低营养环境，观察成纤维细胞在该状态下增殖及细胞周期的变化及对外源性生长因子（bFGF）的反应,探讨低氧、低营养条件下成纤维细胞的病理生理变化。方法: 单纯缺氧环境采用厌氧培养箱，通入混合气，氧分压（PO₂）分为27 mmHg和44 mmHg 2个水平；低营养环境则控制培养液新生牛血清（NCS）浓度。用MTT法检测细胞活性以及其对外源性生长因子的反应，用流式细胞仪检测细胞周期。结果: PO₂ 44 mmHg时细胞增殖速度较同期对照组无明显差异；PO₂ 27 mmHg时，细胞增殖速度较同期对照组明显减慢（P<0.01），细胞被阻滞于G₀期，S期细胞比例明显减少，bFGF未显示促增殖作用。NCS浓度为0.5%的低营养状态下细胞增殖速度较同期对照组明显减慢（P<0.01），细胞被阻滞于G₀-G₁期（P<0.01）；bFGF能明显改善低营养状态下的增殖减慢（P<0.01），使G₂-M期细胞比例增加（P<0.05）。结论: 27 mmHg PO₂或NCS浓度为0.5%的低营养环境使细胞阻滞于G₀-G₁期，影响成纤维细胞增殖；bFGF可以改善低营养条件下细胞增殖减慢的状态，但对极度缺氧条件下的成纤维细胞增殖障碍无明显作用。     

Cadherins in the central nervous system

The central nervous system (CNS) is divided into diverse embryological and functional compartments. The early embryonic CNS consists of a series of transverse subdivisions (neuromeres) and longitudinal domains. These embryonic subdivisions represent histogenetic fields in which neurons are born and aggregate in distinct cell groups (brain nuclei and layers). Different subsets of these aggregates become selectively connected by nerve fiber tracts and, finally, by synapses, thus forming the neural circuits of the functional systems in the CNS. Recent work has shown that 30 or more members of the cadherin family of morphoregulatory molecules are differentially expressed in the developing and mature brain at almost all stages of development. In a regionally specific fashion, most cadherins studied to date are expressed by the embryonic subdivisions of the early embryonic brain, by developing brain nuclei, cortical layers and regions, and by fiber tracts, neural circuits and synapses. Each cadherin shows a unique expression pattern that is distinct from that of other cadherins. Experimental evidence suggests that cadherins contribute to CNS regionalization, morphogenesis and fiber tract formation, possibly by conferring preferentially homotypic adhesiveness (or other types of interactions) between the diverse structural elements of the CNS. Cadherin-mediated adhesive specificity may thus provide a molecular code for early embryonic CNS regionalization as well as for the development and maintenance of functional structures in the CNS, from embryonic subdivisions to brain nuclei, cortical layers and neural circuits, down to the level of individual synapses.     

The dysregulated glomerular cell growth in Denys–Drash syndrome

While diffuse mesangial sclerosis is traditionally described as being the glomerulopathy of Denys–Drash syndrome (DDS), the podocyte proliferative lesions may be overlooked in these DDS cases. In the present study, an evolving process is extrapolated from a selected case of DDS that demonstrated glomerulopathy with conspicuous podocyte proliferation. The observation that podocytes express proliferation markers (Ki67, proliferating-cell nuclear antigen and topoisomerase II) in non-proliferative, mature-looking glomeruli suggests an initial pathogenic act to activate or to keep podocytes from quiescence. The subsequent proliferation of podocytes is in keeping with downregulation of WT1 and cyclin kinase inhibitors of p16 and p21. The emergence of cytokeratin-positive cells in glomeruli that show typical mesangial sclerosis implies elimination of podocytes and replacement with tubular and/or parietal epithelial cells. The final scene of evolving glomerulopathy displays apoptosis and expression of Fas-L and Bax in sclerotic mesangial lesions, which eventually end up with global sclerosis. This novel concept of DDS glomerulopathy implies complex molecular mechanisms involved in glomerular injury.     

Roles of K+ channels in regulating tumour cell proliferation and apoptosis

K⁺ channels are a most diverse class of ion channels in the cytoplasmic membrane and are distributed widely in a variety of cells including cancer cells. Cell proliferation and apoptosis (programmed cell death or cell suicide) are two counterparts that share the responsibility for maintaining normal tissue homeostasis. Evidence has been accumulating from fundamental studies indicating that tumour cells possess various types of K⁺ channels, and that these K⁺ channels play important roles in regulating tumour cell proliferation and apoptosis, i.e. facilitating unlimited growth and promoting apoptotic death of tumour cells. The potential implications of K⁺ channels as a pharmacological target for cancer therapy and a biomarker for diagnosis of carcinogenesis are attracting increasing interest. This review aims to provide a comprehensive overview of current status of research on K⁺ channels/currents in tumour cells. Focus is placed on the roles of K⁺ channels/currents in regulating tumour cell proliferation and apoptosis. The possible mechanisms by which K⁺ channels affect tumour cell growth and death are discussed. Speculations are also made on the potential implications of regulation of tumour cell proliferation and apoptosis by K⁺ channels.     

Relationship between dose of methotrexate, apoptosis, p53/p21 expression and intestinal crypt proliferation in the rat

Abstract Previous studies have shown that apoptosis is induced by cytotoxic chemotherapy and precedes hypoproliferation of intestinal crypt cells. However, the relationship between the degree of intestinal apoptosis and crypt cell hypoproliferation may not be directly related. The purpose of this study was to investigate the relationship between apoptosis and hypoproliferation with increasing doses of chemotherapy. Eleven groups of breast cancer-bearing DA rats were treated with two doses of methotrexate (MTX) i. m. at varying concentrations (0.5, 1.5, 2.5 and 5.0 mg/kg) or saline (control). Animals were killed at 6 or 24 h following treatment. The small and large intestines were examined for apoptosis, villous area (small intestine), crypt length and mitotic count per crypt. Immunohistochemical expression of p53 and p21^waf1/cip1 (p21) were examined quantitatively. Data were analysed using Peritz F-test. Low dose MTX (0.5 mg/kg) did not change p53 expression at 6 h but induced a 15-fold increase in apoptosis in the crypts of the small intestine. This was associated with only a minor reduction in crypt cell proliferation. Higher doses of MTX increased p53 expression and caused a lower (7-fold) but more prolonged peak of apoptosis that was accompanied by reduced villous area, shortened crypts and a more profound reduction in crypt cell proliferation. Unlike the small intestine, apoptosis in the colon was 10-fold lower, proportional to the dose of MTX and did not induce overt damage. Expression of p21 did not change with any dose at either timepoint. We conclude that apoptosis is not always associated with crypt cell hypoproliferation and that the small intestine can recover after low dose MTX despite a heightened peak of apoptosis of crypt cells.     

敌枯双对雄性小鼠生殖细胞分裂比率及精原细胞染色体畸变的影响

本文研究丁敌枯双对BALB/C雄性小鼠生殖细胞分裂比率及精原细胞染色体畸变的影响。将实验小鼠随机分为三组,即实验组(敌枯双组),阳性对照组(环磷酰胺组)和阴性对照组(双蒸水组)。结果发现:敌枯双能明显诱发精原细胞多倍体率和裂隙率增加,抑制终变期/中期Ⅰ和中期Ⅱ细胞的减数分裂比率,促进精原细胞有丝分裂比率。实验结果还提示:在遗传毒理检测中亚急性实验是必要的,并对实验结果进行了初步讨论。