Effect of changes in plasma vitamin E level of vascular responses and lipid peroxidation in sickle cell anaemia subjects.

The effect of vitamin E supplementation (300 mg/day for 6 weeks) on blood pressure, forearm blood flow, forearm vascular resistance, plasma vitamin E level and lipid peroxidation status was investigated in adult sickle cell anaemia subjects. Ten adults whose ages ranged from 19.0 to 25.0 years (mean 22.8+/-0.8 years) were studied. Vitamin E supplementation had little or no effect on arterial blood pressure but significantly increased forearm blood flow (p<0.001) and plasma vitamin E level (p<0.001). However it significantly decreased lipid peroxidation status (p<0.001) and forearm vascular resistance (p<0.001). The change in plasma vitamin E concentration correlated negatively with change in lipid peroxidation status (r=-0.8; p=0.003). However, change in plasma vitamin E concentration correlated positively with change in forearm blood flow (r=0.8; p=0.006). There was an inverse correlation between change in plasma lipid peroxidation and change in forearm blood flow (r=-0.7; p=0.03). The study therefore shows that in sickle cell anaemia subjects, vitamin E supplementation increases forearm blood flow and reduces forearm vascular resistance and lipid peroxidation. The increase in forearm blood flow correlates inversely with the reduction in lipid peroxidation. This suggests that in sickle cell anaemia subjects, vitamin E supplementation could cause an increase in forearm blood flow by decreasing plasma lipid peroxidation level.

Changes in erythrocytes following supplementation with alpha-tocopherol in children suffering from sickle cell anaemia.

INTRODUCTION: Low plasma vitamin E level in children with sickle cell anaemia has been related to elevated level of irreversibly sickled cells which has been implicated in the pathogenesis of painful crisis. In adult patients supplementation with alpha-tocopherol has been shown to reduce irreversibly sickled cell count. In-addition, vitamin E supplementation increases resting forearm blood flow and reduces forearm vascular resistance in adult sickle cell anaemia sufferers. AIM: The aim of the study was to examine the effects of supplementation with alpha-tocopherol on arterial blood pressure, some haematological parameters and osmotic fragility in children suffering from sickle cell anaemia. METHODOLOGY: The effects of supplementation with alpha-tocopherol (100 mg. per day for 6 weeks) on packed cell volume (PCV) haemoglobin concentration ([Hb]), mean corpuscular haemoglobin concentration (MCHC), per cent foetal haemoglobin (% HbF), per cent irreversibly sickled cells (%ISC), erythrocyte osmotic fragility and blood pressure have been assessed in ten (10) children suffering from sickle cell anaemia. Their ages ranged from 4.0 to 10.0 years. RESULTS: Supplementation with alpha-tocopherol significantly increased packed cell volume (p<0.001), haemoglobin concentration (p<0.01) and per cent foetal haemoglobin (p<0.001), but significantly reduced mean corpuscular haemoglobin concentration (p<0.01) and per cent irreversibly sickled cells (p<0.001). alpha-Tocopherol also increased the resistance of the cells to lysis. Supplementation with alpha-tocopherol had little or no effect on arterial blood pressure. CONCLUSION: This study shows that short-term supplementation with alpha-tocopherol may be beneficial to the paediatric sickle cell sufferer.

The effect of warmth or/and vitamin E supplementation on forearm blood flow and forearm vascular resistance in sickle cell and non sickle cell anaemia subjects.

The effects of warmth stimulation and/or supplementation with vitamin E (300 mg/day for 6 weeks) on forearm blood flow (FBF) and forearm vascular resistance (FVR) were measured in 8 sickle cell anaemia (SCA) (mean age = 22.8 + 0.8 years) and 11 non sickle cell anaemia (NSCA) subjects (mean age = 23.2 + 1.1 years) of both sexes. Warmth stimulation was induced by immersing the left foot in warm water at 400C for 2 minutes. Forearm blood flow was measured with the venous occlusion plethysmography method. Warmth increased FBF (p <0.01 in each group) and reduced FVR (p <0.05) in NSCA subjects. The change in FBF was greater (p < 0.05) in the NSCA subjects than in the SCA subjects. Supplementation with vitamin E reduced systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial blood pressure (MAP) (p < 0.001 in each case) in the NSCA subjects but had little or no effect on the SCA subjects. Vitamin E increased FBF in NSCA subjects (p < 0.05) and SCA subjects (p < 0.01) and decreased FVR in both groups (p < 0.05 in NSCA and p < 0.01 in SCA subjects). The change in FVR seen in the NSCA subjects was less (p < 0.01) than the change in SCA subjects. After supplementation with vitamin E, warmth further decreased SBP (p < 0.01 in each group) and FVR (p < 0.01 in each case) and increased FBF in both groups (p < 0.01 respectively). The changes caused by warmth after vitamin E supplementation on the blood pressure parameters, FBF and FVR were similar in the two groups of subjects.

Fasting plasma glucose and cholesterol levels in pregnant Nigerian women.

There are numerous reports of altered carbohydrate metabolism in pregnancy. Normal pregnancy is sometimes characterised by mild fasting hypoglycaemia, postprandial hyperglycaemia and hyperinsulinaemia. Pregnancy has also been observed to be associated with a hypercholesterolaemic state in some individuals with pregnancy-induced hypertension. The aim of the present study was to assess the fasting plasma levels of glucose and cholesterol in pregnant Nigerian women, and to find out any differences from previously reported observations. Twenty pregnant consenting females were used for the study while twenty non-pregnant females were used as controls. Blood samples were taken from each subject after an overnight fast, and assayed for plasma glucose and cholesterol. Results obtained showed a decrease in fasting plasma glucose (from 3.96 mmo1/L to 3.12 mmo1/L) in early pregnancy (p < 0.05) but no change in late pregnancy. Plasma cholesterol was significantly higher (p < 0.05) in pregnant subjects (3.89 mmo1/L) than in the non-pregnant (2.40 mmo1/L), the increase being more appreciable in early pregnancy. These results are similar to data from non-African blacks and Caucasians.

Effects of 2.45 GHz microwave exposures on the peroxidation status in Wistar rats.

One of the consequences of exposures to microwave (MW) radiations is the enhanced production of free O2, free radicals, peroxides and superoxides. The effects on the lipid peroxidation status (LPS) of whole body irradiation of 120 Wistar rats with 2.45 GHz MW at a power density of 6mWcm(-2) have been studied using the MW generator model ER6660E from Toshiba UK Ltd. The LPS in the rats was monitored for a period of 8 weeks post irradiation using thiobarbituric acid (TRA) method. The MW exposures caused an increase in the LPS from the mean control value of 4.18 x 10(-6)g 1(-1)to a maximum of 6.50 x 10(-6) g 1(-1) within the first 24 hrs, and then gradually reduced to control value after about a week. 1mg kg(-1) of ascorbic acid administered before irradiation caused a decrease in the LPS from the control value to a minimum of 2.86 x 10(-6)g 1(-1) within the first week. The value then gradually rose to a maximum of 3.96 x 10(-6)g 1(-1) within the monitoring period. 1 mg kg(-1) of a-tocopherol also administered before irradiation also caused a decrease in the LPS from the control value to a minimum of 2.10 x 10(-6) g 1(-1) within the first week. The value then gradually rose to a maximum of 3.94 x 10(-6) g 1(-1) within the monitoring period. The results obtained from this study demonstrate that MW exposures cause significant increase in the LPS and there are protective effects of the anti-oxidants ascorbic acid and alpha-tocopherol.

The effect of vitamin C and/or warmth on forearm blood flow and vascular resistance in sickle cell anaemia subjects.

This study seeks to examine the effects of vitamin C supplementation or/and warmth on forearm blood flow (FBF) and forearm vascular resistance (FVR) in sickle cell anaemia (SCA) subjects in the steady state. Sixteen (16) SCA subjects of both sexes (mean age, 23.4+/-1.5 yrs.) were studied. Blood pressure (BP, mm Hg) and FBF (ml/min) measurements were made at rest, with warmth stimulation, after vitamin C supplementation for 6 weeks at 300 mg per day and with warmth stimulation after vitamin C supplementation. Warmth stimulation was induced by immersing the left foot in a bowl of water at a temperature of 40 degrees C for 2 minutes. Forearm blood flow (FBF) [corrected] was measured by means of a forearm plethysmograph. Forearm vascular resistance (FVR, arbitrary units) was calculated by dividing mean arterial pressure (MAP) with FBF. Warmth stimulation at 40 C significantly decreased systolic blood pressure (SBP) (p<0.05), diastolic blood pressure (DBP) (p<0.01), MAP (p<0.01) and FVR (p<0.01) but significantly increased FBF (p<0.01). Vitamin C supplementation also significantly reduced SBP (p<0.001), DBP (p<0.01), MAP (p<0.01) and FVR (p<0.05) but significantly increased FBF (p<0.01). After vitamin C supplementation, warmth stimulation potentiated the reduction in SBP (p<0.001), DBP (p<0.01), FVR (p <0.01) and increase in FBF (p<0.01). In conclusion, warmth stimulation at 40 [corrected] degrees C or vitamin C supplementation caused a decrease in arterial blood pressure, forearm vascular resistance and increase in forearm blood flow in sickle cell anaemia subjects. Pretreatment with vitamin C enhanced the vasodilator effect of warmth.

Blood pressure, hematologic and erythrocyte fragility changes in children suffering from sickle cell anemia following ascorbic acid supplementation.

The effect of ascorbic acid supplementation (100 mg/day for 6 weeks) on blood pressure, packed cell volume, irreversibly sickled cells, per cent fetal hemoglobin, hemoglobin concentration, and erythrocyte osmotic fragility was assessed in children suffering from sickle cell anemia. Fifteen children whose ages ranged from 4 to 11 years (7.5 +/- 0.75 years) were studied. Ascorbic acid supplementation reduced systolic blood pressure by 10.9 +/- 3.4 mmHg (p < 0.01), diastolic blood pressure by 7.3 +/- 2.0 mmHg (p < 0.01) and mean arterial pressure by 9.4 +/- 2.6 mmHg (p < 0.01). It significantly increased packed cell volume (p < 0.001), hemoglobin concentration (p < 0.001) and per cent fetal hemoglobin (p < 0.001), but reduced per cent irreversibly sickled cells (p < 0.001). Ascorbic acid supplementation also abolished the long tail of the erythrocyte osmotic fragiligram and increased the resistance of the cells to lysis.