Beta-adrenergic receptors in rat myocardium: Direct detection by a new fluorescent beta-blocker

Summary A new fluorescent -blocker, 9-amino-acridin propranolol (9-AAP), was administered i.v. to rats. Multiple fluorescent 9-AAP binding sites were observed on cardiac muscle cells in frozen sections. Intensity and density of cardiac 9-AAP fluorescence were markedly reduced following pretreatment with (±)- and (–)-propranolol but not with (+)-propranolol. Our findings suggest that 9-AAP may label -adrenergic receptor sites in rat myocardium.D. A. is supported by a fellowship from the Lady Davis Fellowship Trust and by a Research Grant from the Bat-Sheva de Rothschild Fund for The Advancement of Science and Technology. The technical assistance ofA. Itzhak is gratefully acknowledged.     

Does an inhibitor of mitochondrial adenylate kinase also affect oxidative phosphorylation?

Summary Adenylate kinase activity of intact mitochondria is strongly inhibited by Ap₅A, i.e.p ¹,p ⁵-Di (adenosine-5-) pentaphosphate, whereas oxidative phosphorylation is not affected. Therefore, Ap₅A is a useful tool to distinguish between oxidative and non oxidative ATP generating reactions.Acknowledgment. The generous support of Prof. Dr.Walther Lamprecht is gratefully acknowledged. J. L. thanks the Stipendienfonds des Verbandes der Chemische Industrie for a scholarship.     

Organization of myosin molecules in the muscle thick filament

Summary Tryptic treatment of muscle thick filaments reveals the underlying backbones of aggregatedl-meromyosin as a coli of 3 secondary filaments (helical repeat 130 nm) each in turn a coli of a 3 finer ones.     

Ecdysone 20-hydroxylase from the midgut of the tobacco hornworm (Manduca sexta L.)

Summary An ecdysone 20-hydroxylase enzyme system that converts -ecdysone to 20-hydroxyecdysone was prepared from the midgut of the tobacco hornworm prepupa. This partially purified enzyme is NADPH dependent and is localized in the mitochondrial fraction of the midgut tissue.     

Effect of air ionization on blood serotonin in vitro

Summary The effect of negative and positive air ionisation on siliconized blood serotonin was studied in vitro. The experiments showed that within 10 min positive ionisation increased serotonin levels in total blood (+40%), plasma (+90%), erythrocytes (+50%) and thrombocytes (+200%). On the other hand, negative ionization (10 min) lowered the serotonin content of total blood (–30%), plasma (–42.5%), erythrocytes (–41.7%) and thrombocytes (–72.3%), thus confirming the Krueger Effect in vitro.This research was generously supported by a grant from the Joint Research Fund of the Hebrew University and Hadassah, and Dr. and Mrs.Leonard Appleby of Palmbeach, Florida.Acknowledgment: Our thanks are due to Mr.B. Shalita, Mrs.Zippora Adar and Mrs.Olga Fradkin for devoted technical assistance.     

人——管理信息系统中的重要因素

通过对MIS开发普遍失败的原因分析，重点说明了以往在MIS的开发和使用中人的因素所存在的问题。针对我国目前在MIS建设中忽略各种人员对MIS开发成功的影响而产生的问题，提出了应对的措施与建议。     

甘肃地区中强地震活动的时空特点

研究了甘肃地区中强地震的时空分布特征．结果表明，1980-2001年，甘肃地区5级以上地震主要分布在祁连山地震带，地震的频发时段集中在6-10月；中强地震活动的分区特征显著，表现为周期性及成组性．     

甘肃省2000年干旱气候特征和成因诊断分析

针对甘肃省2000年春季至初夏旱和盛夏前伏旱的持续时间、范围、强度进行了对比分析，干旱持续时间之长、范围之大、为近70年所少见．严重的干旱导致夏、秋粮减产、人畜饮水极度困难．干旱形成的原因是中高纬度大气环流“冬性”较强，副热带高压主体面积偏小、位置偏东且偏北，偏南暖湿气流难以到达甘肃上空．这些结果对防灾减灾措施制定和实施及作为短期气候预测的气候背景都有重要参考意义．