In vitro effect of dibenzyl trisulfide on the p50 of the oxygen haemoglobin dissociation curve.

OBJECTIVES: Dibenzyl trisulfide (DTS) has been reported to have cytotoxic and anti-inflammatory effects. It also affects erythrocyte deformability. We investigated the effects of DTS on the p50 of the oxygen haemoglobin dissociation curve. METHODS: Blood samples from 10 healthy male volunteers with normal haemoglobin AA were exposed to 50, 100, 200 and 400 ng/mL, respectively, of DTS. A hemox-analyzer was used to obtain the p50 values. RESULTS: The mean p50 value for the control samples was 25.89 ± 2.18 mm Hg. The values for the samples exposed to 50, 100, 200 and 400 ng/mL were 23.53 ± 1.81 mm Hg, 22.62 ± 1.61 mm Hg, 21.88 ± 1.67 mm Hg and 21.68 ± 1.88 mm Hg, respectively. CONCLUSIONS: DTS caused a significant (p<0.001) reduction in p50 values indicating a shift of the oxygen- haemoglobin dissociation curve to the left in all the samples compared with control, suggesting that the administration of DTS could result in decrease in oxygen supply to tissues.

Sildenafil Increases the p50 and Shifts the Oxygen-Hemoglobin Dissociation Curve to the Right.

INTRODUCTION: Sildenafil (Viagra®) is a selective phosphodiesterase type 5 (PDE5) inhibitor that block the breakdown of cyclic guanyl monophosphate (cGMP) leading to relaxation of the smooth muscles of the corpus cavernous and an increase in blood flow resulting in penile erection. It is hypothesized that sildenafil will increase the release of oxygen from erythrocytes and shift the oxygen-hemoglobin curve to the right. AIM: The aim of this study was to investigate the effect of varying doses of sildenafil on the p50 of the oxygen-hemoglobin dissociation curve in blood samples from eight (8) healthy adult male volunteers with normal hemoglobin HbAA. METHOD: The hemox-analyzer was used to generate the p50 and the oxygen-hemoglobin dissociation curves. MAIN OUTCOME MEASURES: The effect of different doses of sildenafil on the p50 values and shift of the oxygen-hemoglobin curve were the main outcome measures. RESULT: Sildenafil caused a statistically significant increase in the p50 values and rightward shift of the oxygen-hemoglobin dissociation curve. CONCLUSION: Sildenafil caused a dose-dependent increase in the release of oxygen from the erythrocytes as shown by the increased p50 values and rightward shift of the oxygen-hemoglobin dissociation curve. Ellis SS and Pepple DJ. Sildenafil increases the p50 and shifts the oxygen-hemoglobin dissociation curve to the right.

In vitro hemolytic effect of sulfadoxine/pyrimethamine and artemether/lumefantrine on malaria parasitized erythrocytes of female patients.

G6PD is an X-linked gene enzyme that protects erythrocytes from hemolysis when they are exposed to antimalarial drugs because of the effects of the free radicals generated by these drugs. We investigated the effects of Fansidar ™ (Sulfatoxine/Pyrimethamine) and Coartem ™ (Artemether/Lumefantrine) on the hemolysis of malaria parasitized female erythrocytes. Twelve (12) malarious patients attending the University of Benin Teaching Hospital, Benin City, Nigeria, were used in this study. Ten (10) apparently healthy female students from the Medical School, University of Benin, acted as control. Low, normal (the recommended adult dose) and high doses of Fansidar ™ and Coartem ™ were used to determine the percentage hemolysis by checking the absorbance of the various samples. Data was analyzed by the Student's t-test and ANOVA with p<0.05 indicating the level of significance. At low doses of Fansidar ™ and Coartem ™, no hemolysis occurred, while at normal doses, Fansidar ™ showed no hemolysis but significant hemolysis (p<0.05) was observed in the Coartem ™ group. At high doses, both FansidarTM and CoartemTM caused significant (p<0.05) hemolysis. High doses of both drugs and normal dose of CoartemTM caused significant hemolysis. There was no hemolysis observed in the normal dose of FansidarTM and low doses for both drugs, similar to the trend reported for male subjects.