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.     

Differential sensitivity to photohemolysis of erythrocytes enriched with some liposome-carried substances

The sensitivity of human erythrocytes to photohemolysis sensitized by addition of protoporphyrin IX can be selectively affected by their enrichment with substances carried by cationic liposomes. In particular the enrichment which superoxide dismutase is accompanied by a copper-related greater sensitivity toward photohemolysis, as observed in the Down's syndrome (mongolism). Instead it is possible to protect the erythrocytes against the phototoxic effect of protoporphyrin by enrichment with small amounts of beta-carotene.     

An increase in Sendai virus-induced cell fusion of erythrocytes infected with Plasmodium chabaudi

The extent of cell fusion induced by Sendai virus was examined in erythrocytes infected with Plasmodium chabaudi. An increase in cell fusion of erythrocytes with Ehrlich tumor cells and of erythrocytes with erythrocytes was observed with the infected erythrocytes. However, agglutination by the virus was not changed between erythrocytes of normal and malarial mice. These results indicate that the increase in cell fusion occurred in the process of membrane fusion, suggesting that some membrane property of Plasmodium-parasitized erythrocytes is changed in terms of Sendai virus-induced cell fusion.     

An increase in Sendai virus-induced cell fusion of erythrocytes infected withPlasmodium chabaudi

Summary The extent of cell fusion induced by Sendai virus was examined in erythrocytes infected withPlasmodium chabaudi. An increase in cell fusion of erythrocytes with Ehrlich tumor cells and of erythrocytes with erythrocytes was observed wit the infected erythrocytes. However, agglutination by the virus was not changed between erythrocytes of normal and malarial mice. These results indicate that the increase in cell fusion occurred in the process of membrane fusion, suggesting that some membrane property ofPlasmodium-parasitized erythrocytes is changed in terms of Sendai virus-induced cell fusion.We thank Drs George L. Gerton, T. Matsuyama and M. Niwa for their comments on this work and Mr I. Kimata for preparing photographs.     

Tubulin pools in human erythrocytes: altered distribution in hypertensive patients affects Na<Superscript>+</Superscript>, K<Superscript>+</Superscript>-ATPase activity

The presence of tubulin in human erythrocytes was demonstrated using five different antibodies. Tubulin was distributed among three operationally distinguishable pools: membrane, sedimentable structure and soluble fraction. It is known that in erythrocytes from hypertensive subjects (HS), the Na⁺, K⁺-ATPase (NKA) activity is partially inhibited as compared with erythrocytes from normal subjects (NS). In erythrocytes from HS the membrane tubulin pool is increased by ~150%. NKA was found to be forming a complex with acetylated tubulin that results in inhibition of enzymes. This complex was also increased in erythrocytes from HS. Treatment of erythrocytes from HS with nocodazol caused a decrease of acetylated tubulin in the membrane and stimulation of NKA activity, whereas taxol treatment on erythrocytes from NS had the opposite effect. These results suggest that, in erythrocytes from HS, tubulin was translocated to the membrane, where it associated with NKA with the consequent enzyme inhibition.     

Cyclic AMP level in red blood cells of Plasmodium berghei-infected Mastomys natalensis.

The present report describes the changes in cyclic AMP level which occur upon parasitization of red cells by Plasmodium berghei. Parasitized erythrocytes were separated from the non-parasitized population by percoll density-gradient centrifugation. An increase in the cyclic AMP content of both non-parasitized and parasitized erythrocytes of infected animals compared with that of uninfected animals was observed. The patterns of physiological response to isoproterenol in normal, parasitized and non-parasitized erythrocytes were identical.     

Incorporation of14C-thymidine by cultures of erythrocytes from rheumatoid arthritis patients and normal subjects,suggesting the presence of an L-form

Summary Cultures of washed erythrocytes from rheumatoid arthritis patients and normal subjects were found to incorporate¹⁴C-thymidine,suggesting the presence of an L-form. The extent of the incorporation by erythrocytes from rheumatoid patients was more variable than that by erythrocytes from normal subjects, and correlated negatively with IgG measurements and white cell counts performed on the patients' bloods, although not with the clinical activity of the patients.     

Stimulation of methemoglobin reduction by selenium: A comparative study with erythrocytes of various animals

Summary The extent of stimulation of methemoglobin (metHb) reduction by selenite depends upon the level of reduced glutathione (GSH) in the erythrocytes. The reason for the species difference in the effect of selenite was discussed with respect to species differences in the GSH levels in erythrocytes.     

Stimulation of methemoglobin reduction by selenium: a comparative study with erythrocytes of various animals

The extent of stimulation of methemoglobin (metHb) reduction by selenite depends upon the level of reduced glutathione (GSH) in the erythrocytes. The reason for the species difference in the effect of selenite was discussed with respect to species differences in the GSH levels in erythrocytes.     

Cyclic AMP level in red blood cells ofPlasmodium berghei-infectedMastomys natalensis

Summary The present report describes the changes in cyclic AMP level which occur upon parasitization of red cells byPlasmodium berghei. Parasitized erythrocytes were separated from the non-parasitized population by percoll density-gradient centrifugation. An increase in the cyclic AMP content of both non-parasitized and parasitized erythrocytes of infected animals compared with that of uninfected animals was observed. The patterns of physiological response to isoproterenol in normal, parasitized and non-parasitized erythrocytes were identical.     

Deoxyribonuclease immobilized on the erythrocytes

Summary Bovine pancreatic deoxyribonuclease (DNase I) was immobilized on human erythrocytes with several procedures. DNase immobilized on the erythrocytes by chromic chloride showed DNase activity in vitro. Other binding procedures inhibit the immobilized DNase activity.     

Antioxidant and prooxidant roles of copper in Tween 20-induced hemolysis of hamster and pig erythrocytes containing marginal vitamin E

The concentration-dependent effects of copper acting either as an antioxidant or as a prooxidant were examined in vitro using Tween 20-induced hemolysis. When cupric ion concentration was more than 10 M, free copper(II) acted as a prooxidant; both extensive hemolysis and production of unknown thiobarbituric acid-reactive substance occurred in hamster and pig erythrocytes irrespective of vitamin E status. However, when cupric ion concentration was 2–4 M in the incubation medium, copper showed a clear antioxidant activity, reducing both hemolysis and malondialdehyde production induced either by diluted peroxide-containing Tween 20 with ascorbic acid and sodium azide in vitamin E-deficient hamster erythrocytes, or by peroxide-containing Tween 20 in pig erythrocytes containing marginal amounts of vitamin E. Copper(II) is taken up by the erythrocytes, where copper(I)-complexes may contribute to the protection of cells with membrane vitamin E against oxidative radical attack.     

Increased ALA dehydratase activity and spleen weight in lead-intoxicated rats. A consequence of increased blood cell destruction

Summary Lead was given in the diet (1%) to rats from birth and at different times the animals were studied for delta amino levulinic acid dehydratase (ALAD) activity, spleen weight,⁵⁹Fe incorporation in erythrocytes and⁵¹Cr-labeled erythrocytes survival. The increased ALAD and spleen weight found after lead treatment is explained as a consequence of a shortened survival, which results in a younger age of circulating erythrocytes with higher ALAD activity.Supported by Contract No. 140-76-12 ENV. B. of the E. C. Environmental Research Program.     

Increased ALA dehydratase activity and spleen weight in lead-intoxicated rats. A consequence of increased blood cell destruction

Lead was given in the diet (1%) to rats from birth and at different times the animals were studies for delta amino levulinic acid dehydratase (ALAD) activity, spleen weight, 59Fe incorporation in erythrocytes and 51Cr-labeled erythrocytes survival. The increased ALAD and spleen weight found after lead treatment is explained as a consequence of a shortened survival, which results in a younger age of circulating erythrocytes with higher ALAD activity.     

Changes in erythrocyte membrane lipid composition affect the transient decrease in membrane order which accompanies insulin receptor down-regulation.

We have recently demonstrated, using electron paramagnetic resonance (EPR) spectroscopy, that insulin receptor internalization in response to insulin incubation (down-regulation) in human erythrocytes is accompanied by a transient decrease in membrane order, as measured by the 2T' parallel order parameter. Since membrane lipids play such an important role in receptor internalization, we investigated the possible effects that an alteration of the normally-occurring lipid profile might have on down-regulation and the concomitant transient decrease in membrane order. Consequently, human erythrocytes enriched with cholesterol and erythrocytes from cirrhotic patients were examined, because both of these groups of cells have a higher cholesterol/phospholipid molar ratio (CH/PL) than controls. The 5-nitroxystearate spin label, which inserts into the lipid bilayer of cell membranes, was used to monitor changes in 2T' parallel for a 3-h period at 37 degrees C. We report here that both cholesterol-enriched and cirrhotic erythrocytes do not down-regulate, as demonstrated by binding assays, and that they do not show the typical transient decrease in membrane order observed in controls. The results seem to indicate that a more ordered membrane inhibits internalization of the insulin receptor in erythrocytes, and that an increase in membrane disorder is necessary for insulin receptor down-regulation.     

Agglutination of leukemic cells and daunomycin entrapped erythrocytes with lectin in vitro and in vivo

Wheat germ agglutinin (WGA) agglutinated the L1210 leukemic cells and daunomycin entrapped erythrocytes in vitro. Comparing with control preparations, the greatest increase in survival was obtained in vivo when the daunomycin entrapped erythrocytes and WGA were given to BDF1 mice bearing L1210 cells.     

Isolation and characterization of hemagglutinins from the spongeDysidea herbacea

Summary The spongeDysidea herbacea (Keller) was found to possess hemagglutinins. The major component, DHA-I, is a protein with a mol.wt of 26,000, which dissociates into subunits of equal size (14,000). It contains large amounts of glutamic acid and aspartic acid residues, but no half-cystine, methionine or histidine residues. DHA-I reacted with rabbit and human AB0 erythrocytes. D-galactose and lactose were effective inhibitors of DHA-I. The sponge also contained a minor component(s) which reacted preferentially with rabbit erythrocytes but not with human AB0 erythrocytes.Acknowledgment. We thank Dr. M. Yamazaki, Faculty of Pharmaceutical Sciences, Teikyo University, for testing mitogenic activity ofDysidea agglutinins. This study was partly supported by a grant-in-aid for Overseas Scientific Survey from the Ministry of Education, Science and Culture, Japan.     

Isolation and characterization of hemagglutinins from the sponge Dysidea herbacea

The sponge Dysidea herbacea (Keller) was found to possess hemagglutinins. The major component, DHA-I, is a protein with a mol. wt of 26,000, which dissociates into subunits of equal size (14,000). It contains large amounts of glutamic acid and aspartic acid residues, but no half-cystine, methionine or histidine residues. DHA-I reacted with rabbit and human AB0 erythrocytes. D-galactose and lactose were effective inhibitors of DHA-I. The sponge also contained a minor component(s) which reacted preferentially with rabbit erythrocytes but not with human AB0 erythrocytes.     

Agglutination of leukemic cells and daunomycin entrapped erythrocytes with lectin in vitro and in vivo

Summary Wheat germ agglutinin (WGA) agglutinated the L₁₂₁₀ leukemic cells and daunomycin entrapped erythrocytes in vitro. Comparing with control preparations, the greatest increase in survival was obtained in vivo when the daunomycin entrapped erythrocytes and WGA were given to BDF₁ mice bearing L₁₂₁₀ cells.     

Antigens of the blood group I and i on the surfacc of chicken erythrocytes]

I and i blood group antigens have been looked for an Chick erythrocytes using purified and 125 I anti-I, anti-i and anti-I i antibodies. No I antigen is found but i determinants are detected on embryo and adult Chick erythrocytes. This i reactivity is different from the embryonic and adult antigens respectively specific for embryo and adult Chick erythrocytes. Treatment of the erythrocytes with nuraminidase increases the i reactivity. Incubation with papain reduces the fixation of anti-i antibodies suggesting that the i determinant of Chick erythrocyte could be linked to glycopeptide chains.