Effect of low-level chronic x-rays on the hemolytic stability and population composition of peripheral blood erythrocytes

A study was made of the haemolytic stability and population composition of peripheral blood erythrocytes of rats chronically exposed to X-radiation of 0.258 mC/kg/day during 30 days. Haemolytic stability of erythrocytes changed at cumulative doses of 2.58, 5.16 and 7.74 mC/kg. Percentage of some erythrocyte fractions obtained by fractionation in a sucrose density gradient was found to change after irradiation with cumulative doses of 5.16 and 7.74 mC/kg.     

Effect of ethanol,temperature and pH on the stability of killer yeast strains

The effects of temperature, pH and ethanol on the stability of killer wine yeasts were studied. Laboratory and collection strains as well as the strains prepared by the protoplast-fusion technique were used and a decline of killing activity was observed in the complete medium and in grape juice. The relationship between the loss of killer properties in fusant strains and the stability of the original donor strain was established. The negative effect of the ethanol addition on the killer character of the strains used and the possibilities of its stabilization are discussed.     

The surface characteristics of the erythrocytes in hemolytic disease of the newborn]

Assessment of structural state of the erythrocyte (Er) surface was done in accordance with the capability of overmembranous glycoproteins and glycolipids of sorbing the vital stain Alcian blue (AB). The extent of AB sorbing by the Er surface of healthy infants is nearly 5.51.10(-13) g per cell, whereas in children with hemolytic disease of newborns (HDN) under average grave condition, and in children with HDN and concomitant diseases this index is seen to reduce significantly down to 82.4 and 70.8 per cent, respectively, which may be due presumably to the masking of glycocalyx with Er antibodies. A tendency to the same change appears in hyperbilirubinemia of vague etiology. There as a true increase in AB sorbing with the grave form of HDN (up to 121.8%). This is perhaps because of the increase in Er external membrane permeability to stain and because of the increased sorbing of the stain by intracellular components.     

Effect of a "direct" hemolytic factor and phospholipse A2 from Middle-Asian cobra venom on erythrocytes]

The effect of "direct" hemolytic factor (DHF) and phospholipase A2, isolated and purifed from Middle-Asian cobra venom on human erythrocytes is studied. DHF is found to increase the hemolytic effect of phospholipase A2 Ca2+ ions inhibit the hemolytic effect of DHF, but they increase the hemolysis in the presence of DHF and phospholipse A2. Heparin re moves the increasing effect of DHF. Possible mechanisms of the hemolytic effect of DHF and phospholipase A2 are discussed.     

The effect of ethanol on continuous culture stability

The stability characteristics of a continuous culture system were studied following the addition of the natural product inhibitor, ethanol. For a steady state culture of Klebsiella (Aerobacter) aerogenes there was a linear dependence of growth rate on ethanol concentration. Following impulse and step addition of the inhibitor, response patterns of the growth rate (μ) and overall metabolism (Q_o2, Q_Co2, Q_AC) were observed. A mathematical model of the transient behavior of a product-limited system is proposed, and analog computer solutions fitted to the experimental data. The transient response of the growth rate could best be described by second or higher order equations, e.g., with values of the second order time constant (T₂) = 5 min, and damping coefficient (ξ) = 0.4.     

Effects of glycerol on the thermal dependence of the stability of human erythrocytes

Incubation of human blood in saline solution of 0–36% (v/v) ethanol for 30 min produces lysis or stabilization of erythrocytes depending on the ethanol concentration. Under less elevated concentrations of ethanol, erythrocytes are present in expanded shapes (R state) that present lower stability and suffer lysis with increase in the ethanol concentration. Under more elevated concentrations of ethanol, erythrocytes are present in contracted shapes (T state) that have higher stability and suffer lysis at even more elevated ethanol concentrations. This work evaluated the effects of glycerol (0 to 2.0 M) and temperature (7 to 47°C) on the stability of the R erythrocytes, characterized by the ethanol concentration at the mid-transition point (D _50R ) of the hemolysis curve (D _50R ). D _50R declined sigmoidally with increase in the glycerol concentration or temperature, due to transition of the R to the T state erythrocytes. In 1.5 M glycerol, the erythrocytes stability decreased below 32 but increased above 37°C. The combination of temperature, glycerol and ethanol actions generates a critical value of osmotic pressure below which the R state predominates and above which the T state predominates. At 7°C 1.5 M glycerol decreased the erythrocytes stability against ethanol but increased the erythrocytes stability against hypotonic shock. Those conditions favor the R state, which has a lower stability against ethanol; however, in the absence of ethanol, glycerol determines less water entrance in the erythrocytes, making more difficult its lysis by hypotonicity.