Expression of Bcl-2 and bax in the frontoparietal cortex of the rat following cardiac arrest

Following 10-min cardiac arrest and resuscitation, male Sprague-Dawley rats developed posthypoxic myoclonus. This phenomenon peaked at 14 days and disappeared by 45 days after cardiac arrest. The mechanisms for the initial dysfunction and later restoration of motor function are not completely known. In the present study, involvement of Bcl-2 and Bax in these phenomena was investigated. In the frontoparietal cortex, both bcl-2 and bax mRNA levels were significantly increased 1, 3, 7, 14, and 28 days postresuscitation. bax mRNA levels continued to be high 45 days postcardiac arrest, whereas bcl-2 mRNA levels were returned to control levels. The apoptotic cells were found in layers IV to VI of the frontoparietal cortex of rats 3 days postcardiac arrest. These results indicate that after cardiac arrest, the initial rise of Bax levels may mediate apoptosis and neurodegeneration in the rat brain. At later time points, increased levels of Bcl-2 may contribute to recovery of motor function in posthypoxic rats.     

硝基(芳亚胺基)二乙基硫代硫酸钠和硝基苯丙氮酸衍生物的合成和放射增敏作用

乏氧细胞对射线所具有的较大抗性是对某些人类肿瘤进行放疗失效的主要原因。放射增敏剂的研究目的是为了提高射线在正常组织可耐受剂量下对肿瘤细胞的杀伤率,从而提高放疗效果。目前试用于临床的放射增散剂misoniizole(MISO)是一种硝基咪唑类化合物,由于其较强的神经毒性,限制了这种药物的推广和使用。为寻找新的低毒有效的放射增敏剂,我们设计并合成了一系列化合物,试验了它们对离体Hela-S_3细胞的放射增敏作用。     

硝基(芳亚胺基)二乙基硫代硫酸钠和硝基苯丙氮酸衍生物的合成和放射增敏作用

A series of compounds was synthesized, these compounds were tested for Hela-S₃cells in vitro for radiosensitizing activity. Five of them are 2,2′- (arylimino)-diethyl-sodium thio-sulfate and two of them are phenylalanine derivatives. Most of them showed various degrees of ra-diosensitizing activity. Among them, SER of L07 was 1.89 at 3 mmol, and had low cytotoxicity toHela-S₃ cells;ID₅₀ was 18.8 mmol. The relationship between radiosensitizing effects and chemicalstructure was discussed. It offers a base for further exploration of selectively hypoxic cell radiosens-itizers.     

赤芝子实体中灵芝酸类成分的研究

自赤芝［Ｇａｎｏｄｅｒｍａｌｕｃｉｄｕｍ（Ｆｒ．）Ｋａｒｓｔ．］子实体的二氯甲烷提取物中分离得到一个新的四环三萜化合物，命名为灵芝酸ＤＭ（ｇａｎｏｄｅｒｉｃａｃｉｄＤＭ，Ｉ）。根据光谱（ＵＶ，ＩＲ，１ＨＮＭＲ，１３ＣＮＭＲ，ＭＳ２ＤＮＭＲ）分析，确定其结构为Ｉ式。同时还分离得到二个已知的灵芝酸类化合物，即灵芝酸Ａ（ｇａｎｏｄｅｒｉｃａｃｉｄＡ，Ｉ）和灵芝酸Ｃ（ｇａｎｏｄｅｒｉｃａｃｉｄＣ，ＩＩ）。     

Carcinoma of the breast: detection with MR imaging versus xeromammography

Detectability of breast cancer with magnetic resonance (MR) imaging versus xeromammography was quantitatively compared. MR images were obtained of breasts of 120 women who underwent xeromammography. T1 values were determined for masses larger than 2 cm. Cancer was histologically confirmed in 39 breasts and was considered excluded from 81 due to results of biopsy, cyst aspiration, or sonography or absence of change in xeromammographic findings over time. Images were blindly interpreted by three observers, and results were expressed as receiver operating characteristic curves. Detectability of breast cancer was substantially better with xeromammography than with MR imaging for all observers (P less than .03, 10(-6), and .001). On MR images, spiculation of a mass, distorted architecture, skin thickening, and nipple or skin retraction were specific but relatively insensitive indicators of cancer. Masses with smooth, distinct margins and signal intensity greater than that of fat on T2-weighted images were always benign. Other findings and T1 values were not diagnostically useful. The authors conclude that xeromammography is superior to MR imaging in detection of breast cancer.     

Salusin beta is a surrogate ligand of the mas-like G protein-coupled receptor MrgA1

The mas-like G protein-coupled receptors form a subfamily of G protein-coupled receptors that includes variable member numbers across different species and that have been shown to bind a wide variety of ligands from peptides to amino acid derivatives. While screening a library of peptides against different orphan G protein-coupled receptors, we found that human salusin beta activates the mouse mas-like G protein-coupled receptor, mMrgA1 with an EC(50) of about 300 nM. Salusin beta is a bioactive peptide recently discovered through bioinformatics analysis which stimulates arginine-vasopressin release from rat pituitary and causes rapid and profound hypotension and bradycardia. However, when we further analyzed the generality of the mMrgA1 activation, we found that human salusin beta does not activate corresponding human mas-like G protein-coupled receptors. Our results show that human salusin beta is a surrogate ligand of the mouse MrgA1 and raises a cautionary flag for experiments that analyze the pharmacological profiles of mas-like G protein-coupled receptors from different species.