Mast cell activation markers for in vitro study

ABSTRACT

Mast cells (MCs) are well known for their role in allergic conditions. This cell can be activated by various types of secretagogues, ranging from a small chemical to a huge protein. Mast cell activation by secretagogues triggers the increase in intracellular calcium (iCa²⁺) concentration, granule trafficking, and exocytosis. Activated mast cells release their intra-granular pre-stored mediator or the newly synthesized mediator in the exocytosis process, in the form of degranulation or secretion. There are at least three types of exocytosis in mast cells, which are suggested to contribute to the release of different mediators, i.e.,, piecemeal, kiss-and-run, and compound exocytosis. The status of mast cells, i.e., activated or resting, is often determined by measuring the concentration of the released mediator such as histamine or β-hexosaminidase. This review summarizes several mast cell components that have been and are generally used as mast cell activation indicator, from the classical histamine and β-hexosaminidase measurement, to eicosanoid and granule trafficking observation. Basic principle of the component determination is also explained with their specified research application and purpose. The information will help to predict the experiment results with a certain study design.     

Temporal discrimination in the cerebellar cortex during conditioned eyelid responses

Little is known about mechanisms used by the nervous system to encode time. In light of recent evidence, cerebellar cortex involvement in the learned timing of conditioned eyelid responses shows promise as an area of investigation into neural timing mechanisms. Lesion studies indicate that the cerebellar cortex is necessary for response timing, but do not rule out the possibility that response timing is encoded afferent to the cerebellum. To differentiate between precerebellar and cerebellar cortical timing mechanisms, rabbits were trained by pairing direct stimulation of mossy fibers in the cerebellum as the conditioned stimulus (CS) with an eyeshock unconditioned stimulus (US). We find that individual animals can produce diffently timed conditioned responses when trained with a mossy fiber CS that has been paired with the US at various interstimulus intervals. The fact that differently timed responses can be conditioned using constant-frequency stimulation of an invariant subset of mossy fibers as the CS suggests that timing information in the afferent input to the cerebellum is not essential. Two rabbits trained with single-pulse stimulation in the cerebellum as the CS also learned differently timed conditioned responses; suggesting that fiber recruitment during a stimulus train does not convey the necessary temporal coding to the cerebellar cortex. Together with the lesion data, these findings suggest that the learned timing of conditioned eyelid responses occurs in the cerebellar cortex. Received: 25 August 1997 / Accepted: 12 January 1998     

An electron microscopic and immunohistochemical study of Merkel cell carcinoma

Two cases of Merkel cell carcinoma (MCC) were examined by electron microscopy and immunohistochemistry. Histologically, tumor cells, which extended from the dermis into the subcutis, showed anastomosing bands with partial trabecular pattern. The ultrastructural study showed tumor cells in case 1 with numerous neurosecretory granules. The number of granules in case 2, however, was smaller compared with that in case 1. Perinuclear bundles of filaments were present in case 2, but few bundles were observed in case 1. By immunohistochemistry, cytokeratin (CK)-8, -18, -19, and -20 and epithelial membrane antigen were stained positively within tumor cells in both cases. It was interesting that staining patterns of chromogranin A and of neuron-specific enolase were different in the two cases. These data indicated that CK-20 is a useful marker for diagnosing MCC and that ultrastructural and immunohistochemical differences in both cases were the result of phenotypic variation.     

Hydrogen peroxide mediates damage by xanthine and xanthine oxidase in cerebellar granule neuronal cultures

The free radical-generating system of xanthine and xanthine oxidase is commonly used experimentally as a source of superoxide anion, which can produce oxidative stress, leading to cellular damage and death. Models of oxidative stress are important in elucidating pathologies associated with increased levels of reactive oxygen species, including stroke and neurodegenerative diseases, such as Alzheimer's and Parkinson's diseases. We therefore, examined the effect of the xanthine/xanthine oxidase system on the viability of postnatal cerebellar granule neurones obtained from 8-day old Sprague–Dawley rat pups. Xanthine (100 μM) and xanthine oxidase (0.02 U/ml) applied for 1 or 6 h reduced the viability of cells at 8 div assessed using the alamar blue assay, and induced morphological changes, such as shrinkage of the cell bodies and neurites. Heat-inactivation of xanthine oxidase resulted in complete loss of its activity. Superoxide dismutase (250 U/ml) failed to modify the damage by xanthine and xanthine oxidase, while catalase (250 U/ml) completely prevented it. When applied alone, xanthine oxidase significantly lowered cell viability, an effect that was blocked by allopurinol and catalase, but not by superoxide dismutase. The results indicate that xanthine and xanthine oxidase can produce predominantly hydrogen peroxide instead of the superoxide anion. Cerebellar granule cells in culture may also possess significant levels of endogenous xanthine.     

神经生长颗粒对大鼠腓总神经横断损伤的修复作用

目的 研究神经生长颗粒(NGG)对大鼠腓总神经横断损伤的修复作用.方法 SD大鼠50只,随机分为NGG高、中、低剂量组(剂量分别为5.2g生药/kg、2.6g生药/kg、1.3g生药/kg)、弥可保组(剂最为625μg/kg)、空白对照组.行大鼠腓总神经横断缝合术,术后每日灌胃给药.于术后2周、3周、4周行足迹实验,测定展趾功能,术后4周行电生理检测,测定复合肌动作电位和神经干动作电位检测,组织形态学分析,测定再生有髓神经纤维数、髓鞘厚度和胫前肌肌纤维截面积,观察NGG对大鼠腓总神经损伤的修复作用.结果 与空白对照组相比,NGG组展趾功能、复合肌动作电位和神经干动作电位波幅及恢复率、再生有髓神经纤维计数、髓鞘厚度及胫前肌横截面积均显著增高,且呈剂量依赖的量效关系.结论 NGG有利于轴突生长和髓鞘形成,可以促进大鼠损伤神经修复和神经功能的恢复.     

Endocrine Cells in a Normal Breast and Non-cancerous Breast Lesion

The authors confirmed the presence of endocrine cells for the first time in a normal breast as well as in a non cancerous lesion of the breast. One hundred and eighty eight blocks of normal breast tissues in 44 cases and 74 blocks of non cancerous lesions in 35 cases were examined. Argyrophil cells were found in one block from a normal breast and in one block from a phyllodes tumor. Argyrophil cells in the normal breast showed positive reaction to anti-endocrine granule constituent (EGC) antibody with immunohistochemical method. Argyrophil cells found in the phyllodes tumor gave positive reaction to both anti EGC and anti-serotonin antibodies. The present study is thought to be the first report in the literature of serotonin-positive cells in a non-cancerous breast lesion, a phyllodes tumor. Acta Pathol Jpn 41: 874-878, 1991.     

脑康复冲剂对大鼠软脑膜微循环作用的实验研究

目的：脑康复冲剂临床用于治疗脑血栓血瘀证患者，本实验观察其对在大鼠实验性软脑膜微循环障碍的影响。方法：大鼠预防性给药，用高分子右旋糖酐水溶液静脉注射形成大鼠软脑膜的微循环障碍，观察脑康复冲剂对大鼠微循环的影响。结果：用高分子右旋糖酐造模后，大鼠软脑膜的微循环发生障碍，表现为血液流速减慢、血细胞聚集等，脑康复冲剂组血流速度开始减慢的时间明显比生理盐水对照组延长，且分级数也明显优于生理盐水组，对高分子右旋糖酐造成的血液流态障碍，脑康复组明显好于生理盐水组（P＜0．05），毛细血管网交叉点数开始减少的时间也比生理盐水对照组延长，差异显著（P＜0．01）。结论：脑康复冲剂使大鼠血流速度和血液流态得到改善，具有预防和改善动物脑微循环障碍的作用。