Pathogenic Characterization of Clostridium perfringens Strains Isolated From Patients With Massive Intravascular Hemolysis

Sepsis caused by Clostridium perfringens infection is rare but often fatal. The most serious complication leading to poor prognosis is massive intravascular hemolysis (MIH). However, the molecular mechanism underlying this fulminant form of hemolysis is unclear. In the present study, we employed 11 clinical strains isolated from patients with C. perfringens septicemia and subdivided these isolates into groups H and NH: septicemia with (n = 5) or without (n = 6) MIH, respectively. To elucidate the major pathogenic factors of MIH, biological features were compared between these groups. The isolates of two groups did not differ in growth rate, virulence-related gene expression, or phospholipase C (CPA) production. Erythrocyte hemolysis was predominantly observed in culture supernatants of the strains in group H, and the human erythrocyte hemolysis rate was significantly correlated with perfringolysin O (PFO) production. Correlations were also found among PFO production, human peripheral blood mononuclear cell (PBMC) cytotoxicity, and production of interleukin-6 (IL-6) and interleukin-8 (IL-8) by human PBMCs. Analysis of proinflammatory cytokines showed that PFO induced tumor necrosis factor-α (TNF-α), IL-5, IL-6, and IL-8 production more strongly than did CPA. PFO exerted potent cytotoxic and proinflammatory cytokine induction effects on human blood cells. PFO may be a major virulence factor of sepsis with MIH, and potent proinflammatory cytokine production induced by PFO may influence the rapid progression of this fatal disease caused by C. perfringens.

INFLUENCE OF MILLIMETER RANGE ELECTROMAGNETIC WAVES ON HEMOLYSIS KINETICS OF RAT BLOOD ERYTHROCYTES

The effect of millimeter range electromagnetic waves (MM EMW) on kinetics of acidic hemolysis of rat blood erythrocytes has been studied. It was shown that MM EMW affect the duration of erythrocyte hemolysis and this change depends on MM EMW exposure and frequency. At the irradiation by frequencies 41.8 and 42.2 GHz the acidic hemolysis occurs quicker at all durations of the irradiation compared to the control. At the irradiation by 50.3 and 51.8 GHz the hemolysis takes place quicker as well, as compared to the control at short durations of the irradiation. At the exposure 60 min the hemolysis start is delayed.

Development of an Automated Device for the Procedure of Blood Transfusion in Newborns

Hemolytic disease of the newborn, also known as hemolytic disease of the fetus and newborn, HDN, HDFN, is a problem of fetal erythrocyte hemolysis. This may happen due to the sensitization of maternal antibodies through the placental route. It is the pathology most frequently found in neonatal patients. Approximately 98% of maternal alloimmunization cases by erythrocyte antigens are due to the RhD factor. Phototherapy is the first choice in the treatment of neonatal jaundice. Blood transfusion is the therapy instituted for the treatment of severe neonatal disease. This study aimed to develop an automated device for performing the blood transfusion procedure. The method was developed in four stages: (1) Literature review about the search for theoretical references based on scientific articles and textbooks on transfusion therapy in the newborn; (2) Elaboration of the device consisted of items related to its assembly and structuring; (3) Operation of the medical device, including specific schedules related to the execution of the procedure; (4) Performing tests with simulating the purpose of volume replacement in the total cycle performed in the exsanguine transfusion procedure. The results showed that it was possible to assemble, reproduce, and implement the automation of the device developed for the exsanguine transfusion procedure in a practical. Also, the procedure presented security and effectiveness in the clinical treatment related to HDN.

ERYTHROCYTE FREEZING DURING THE MODIFICATION IN COMPOSITION OF CRYOCONSERVANT BASED ON GLYCEROL

Damage to red blood cells occurring during freezing can also develop with transfusion. An increase in the concentration of free iron in the blood during the destruction of red blood cells results in an acceleration of the reactive oxygen species production, peroxide damage to cells and stimulation of inflammation. With multiple transfusions of red blood cells, the function of internal organs may be impaired as a result of iron overload. The cryoprotective properties of glycerol include its collegiate ability to reduce the concentration of NaCl at temperatures below 0°C. However, it was found out that the cryoprotective efficacy of glycerol was far less than it was expected from its colligative properties. Damage to red blood cells during their rapid thawing is the result of osmotic shock due to the inability of an excess of intracellular glycerol to exit the cells quickly enough to prevent their swelling and hemolysis. These data indicate the need to reduce the glycerol concentration in the cryoconservant. However, maintaining the protective effectiveness of the cryoprotectant requires a decrease in the NaCl concentration. This study investigates the effect of the composition of the cryoconservant on erythrocyte hemolysis during freezing and hypothermic storage. We used 2 types of cryoconservants: a) 38% (w / v) glycerin, 2.9% sorbitol, 0.63% NaCl (standard composition); b) 28% (w / v) glycerol, 6.8% sorbitol, 0.25% NaCl (modified composition). It was found out that a decrease in the concentration of glycerol and an increase in the concentration of sorbitol leads to a decrease in the erythrocyte hemolysis. The results obtained suggest that a change in the composition of the cryoconservant will reduce osmotic stress during thawing of red blood cells, which, in turn, will reduce their destruction upon transfusion and the likelihood of inflammation.