Plasmodium berghei: inhibition by splenectomy of a paralyzing syndrome in infected rats

In recent attempts to isolate the factor causing paralysis in rats infected with a mousepassed KBG 173 strain of Plasmodium berghei Splenectomy was employed. The effects of Splenectomy on the paralyzing syndrome are discussed in the present report. Paralysis was inhibited in rats splenectomized prior to inoculation. Serial bloodpassaging of the strain in the splenectomized host however, apparently enhanced its virulence. Spleen-intact rats used as controls exhibited a marked increase in incidence of paralysis. Rats splenectomized a day before paralysis became evident were paralyzed significantly more frequently than those splenectomized a day earlier, indicating the apparent requirement of an incubation period for the expression of the paralytic effect. The enhanced virulence did not appear to be related to the level of parasitemia of the splenectomized rats used as donors. The spleen appears to provide the optimal conditions required for the elaboration of the paralyzing factor.     

Results of the study of preventive effectiveness and side effects of anti-influenza lactoglobulin in controlled epidemiologic trial]

Prophylactic activity and side action of antiinfluenza lactoglobulin were studied under conditions of controlled epidemiological trial in 6361 persons during the epidemiological rise of influenza incidence. The data obtained pointed to the absence of any protective effect of antiinfluenza lactoglobulin. Marked allergenic properties of lactoglobulin and development of sensitization in the persons under observation were found during the study of the side-effect of the preparation. Thus, the absence of prophylactic efficacy and the sensitizing action of antiinfluenza lactoglobulin pointed to the inexpediency of its use for prophylactic and therapeutic purpose.     

Effect of ethionine on dolichyl phosphate-dependent transglycosylation reactions in rat liver

Dolichyl phosphates of different chain length (C35, C55 , C75 , Dol-mixture of C90 , 95, 100, 105 and C110 ) were tested as lipid acceptors in transglycosylation reactions. In the absence of exogenously added dolichyl phosphates there were no differences in the rate of synthesis in liver of dolichyl phosphate mannose, dolichyl phosphate glucose and dolichyl pyrophosphate N-acetylglucosamine between normal and ethionine-treated animals. Addition of exogenous dolichyl phosphates of different chain length stimulated the synthesis of dolichyl phosphate mannose and dolichyl pyrophosphate N-acetyl-glucosamine 2 to 4 times depending on the chain length of dolichols , both in normal and ethionine-treated animals. In liver of ethionine-treated rats the formation of dolichyl phosphate glucose was not stimulated. Following ethionine treatment the concentration of free and esterified with fatty acids dolichols was increased.     

Does calmodulin participate in the regulation of the Ca-pump of erythrocytes in vivo?

Using a highly effective chelator of Ca2+ and 45Ca, the concentration of Cai2+ in human and rat erythrocytes was measured both at normal and accelerated Ca2+ influx into the cells. No effect of the calmodulin-dependent reaction inhibitor R24571 was observed. The Ca-ATPase from saponin-treated erythrocytes was characterized by a high affinity for Ca2+ (K 0.5-0.7 microM). This value is 2-3 times as low as that for Ca2+ concentration causing a 50% increase of the Ca-ATPase activity in erythrocyte ghosts obtained during hypoosmotic hemolysis. The Ca-ATPase activity in saponin-treated erythrocytes did not change either under the effect of calmodulin or by R24571. It was assumed that calmodulin did not participate in the regulation of the Ca2+-pump operation in erythrocytes in vivo.     

Structural identity of active sites of RNases

It is known that the affinity of all nucleoside monophosphate isomers for RNAase active sites increases in the following order: 5'-NMP----3'-NMP----2'-NMP, irrespective of the RNAase type (pyrimidine-specific, guanine-specific or non-specific) and stage of activity (transferase, hydrolase). It is known also that the nucleotides with the same degree of isomerism have substantially the same conformation. It was thus supposed that the structure of active sites of RNAase has common features with a closer similarity in case of pyrimidine-specific (EC 3.1.4.22), guanine-specific (EC 3.1.4.8) and non-specific (EC 3.1.4.23) RNAases.