Role of oxygen radicals scavenging enzymes in the protoporphyrin induced photohemolysis

Summary Inhibition of superoxide dismutase by diethyldithiocarbamate or cyanide increases the rate of red blood cells lysis after irradiation in the presence of protoporphyrin IX. Catalase activity, which is decreased during the photohemolytic process, appears to be not essential for the lytic event. No relationship between catalase activity and hemolysis rate was found. Superoxide dismutase appears to prevent only in part catalase inactivation by singlet oxygen.     

Role of oxygen radicals scavenging enzymes in the protoporphyrin induced photohemolysis

Inhibition of superoxide dismutase by diethyldithiocarbamate or cyanide increases the rate of red blood cells lysis after irradiation in the presence of protoporphyrin IX. Catalase activity, which is decreased during the photohemolytic process, appears to be not essential for the lytic event. No relationship between catalase activity and hemolysis rate was found. Superoxide dismutase appears to prevent only in part catalase inactivation by singlet oxygen.     

Post-irradiation induced sensitization of inhibition of oxidative phosphorylation by iodoacetamide

Zusammenfassung Zugabe von Iodazetamid während und nach der Bestrahlung von isolierten Lebermitochondrien der Ratte sensibilisiert die strahleninduzierte Hemmung der oxydativen Phosphorylierung. Die Nachbehandlung lässt einen latenten Strahlenschaden sichtbar werden, der selber vermutlich in einer Produktion latenter ATPase besteht. Es ist wahrscheinlich, dass die bekannte strahlensensibilisierende Wirkung von Iodacetamid bei Lebewesen und Zellen auf dieser Hemmung der ATP-Produktion beruht, welche Erholungsprozesse erschwert.

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Acknowledgment: The author is indebted to M. R.Aeschbacher for her technical assistance.

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The experiments were supported by a grant from the Swiss National Fund.     

Histamine release by passive sensitization with murine neoplastic mast cells in vitro

Riassunto Mastociti neoplastici di un clono diploide, coltivati nel topo come tumore-ascite, sono stati impiegati per produrre nel coniglio un antisiero specifico verso celiule dello stesso clono. L'incubazione con l'antisiero produce liberazione di istamina da parte di mastociti dello stesso clono; l'effetto non si osserva se i mastociti sono incubati con sieri ottenuti dagli stessi animali prima della sensibilizzazione. Viene prospettato 1'uso di questo modello sperimentale per sue possibili applicazioni allo studio iella liberazione dell'istamina nella sensibilizzazione passiva dei mastociti.

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The present investigation has been aided by grant NB 00940 from the National Institute of Neurological Diseases and Blindness. The experiments have been performed during one year's tenure of a N.A.T.O. Fellowship at the Department of Pharmacology, Yale University, New Haven, Connecticut.     

Selective inactivation of catalase during protoporphyrin induced photohemolysis of human red blood cells

Summary The level of some enzymatic activities in red blood cells before and after photohemolysis induced by protoporphyrin IX was studied. A 30% decrease in catalase activity was found both in normal erythrocytes and those from patients affected by favism. Other proteins though present in larger amounts inside the erythrocytes are not affected by the photohemolytic process.     

Selective inactivation of catalase during protoporphyrin induced photohemolysis of human red blood cells

The level of some enzymatic activities in red blood cells before and after photohemolysis induced by protoporphyrin IX was studied. A 30% decrease in catalase activity was found both in normal erythrocytes and those from patients affected by favism. Other proteins though present in larger amounts inside the erythrocytes are not affected by the photohemolytic process.     

Differential activation of two monoamine oxidase types by oxygen

Summary The stimulation of rat brain monoamine oxidase activity by oxygen is shown to be type-selective, type B being much more strongly stimulated than type A.Pargyline and clorgyline were gift samples from Abbott Laboratories, USA and May and Baker Ltd, England respectively     

Methyl cellosolve-induced sensitization of mice to bacterial endotoxin

Summary Treatment of mice with a sublethal dose of methyl cellosolve renders the animals 64-fold more sensitive to the toxic effects of bacterial endotoxin.Acknowledgments. I would like to thank Mr Larry Davis for his excellent technical assistance in these studies.This work was supported by the Naval Medical Research and Development Command, Research Work Unit No. MF585240013.1026. The opinions and assertions contained herein are the private ones of the writer and are not to be construed as official or reflecting the views of the Navy Department or the naval service at large. The experiments conducted herein were conducted according to the principles set forth in the Guide for the Care and Use of Laboratory Animals, Institute of Laboratory Resources, National Research Council.     

Potentiation of the immunosuppressive effects of cytoxan by hyperbaric oxygen

Zusammenfassung Die intermittierende Anwendung hyperbarischen Sauerstoffs erhöht die die Antikörper unterdrückende Wirkung von Cytoxan bei Mäusen, die vorher mit Ochsenserum-Albumin und Freunds Adjuvans immunisiert worden waren. Der Wirkungsmechanismus des Sauerstoffs wird als Verhinderung der Transformation von kleinen Lymphocyten in immunbiologisch aktive Stammzellen gedeutet.

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Supported by U.S. Atomic Energy Commission Contract No. RLO-1927-13.     

A nonenzymic oxygen uptake and its implications in the assay of 4-hydroxyphenylpyruvate dioxygenase by an oxygen electrode

Summary The oxygen electrode provides a rapid, convenient assay for 4-hydroxyphenylpyruvate dioxygenase. However, due to the occurrence of a nonenzymic oxygen consumption when reducing agents were mixed witha,a-dipyridyl, its use is restricted to species which do not require reducing agents or necessitates the addition of catalase to the reaction mixture.     

太阳风正负动压脉冲激发磁层ULF波的数值模拟

磁层中的超低频波动（Ultra Low Frequency Wave,简称ULF波）通常被认为是由外界太阳风／行星际磁场扰动或者磁层内部的等离子体不稳定性激发的．当太阳风动压脉冲作用于磁层顶时,可能在磁层内部激发ULF波,从而将太阳风能量输运到地球磁层中．本文利用磁流体力学（MHD）数值模拟研究不同形式的太阳风动压脉冲作用下,在磁层中激发的ULF波的性质．我们主要关注地球磁层对太阳风动压正／负脉冲以及太阳风动压正．负脉冲对的响应．模拟结果表明,幅度和周期均相同的太阳风动压正脉冲和负脉冲,在磁层中所激发的ULF波幅度,周期均相同,然而相位相差180°．另外,对一个太阳风动压正一负脉冲对作用于偶极磁层的情况,在地球磁层内的某些特定区域仍可观察到磁力线共振（FLRs）现象,磁力线共振的区域分布和动压脉冲的周期以及动压脉冲对之间的时间间隔有关．同时模拟计算结果还表明,与单一脉冲相比较而言,在动压脉冲对的作用下,太阳风能量可以传递到地球磁层中更低纬度的区域．因此本文结果可以帮助我们更好地理解太阳风能量通过ULF波形式输运到地球磁层的机制;同时,还可以为研究有关内磁层中能量粒子对不同的行星际激波的响应方式提供线索．