Intracellular sodium and potassium and their relationship to blood pressure and body size

In the present study twenty-seven hypertensive patients, thirty-five normotensives without familial hypertension and twelve normotensives with familial hypertension were studied cross-sectoinally with regard to their age, sex, body mass index and - most important of all - the electrolyte (sodium and potassium) composition of their red and white blood cells. The major aim of this study was to find out if there were differences between the above mentioned subject groups regarding the electrolyte composition (sodium and potassium) of their blood cells. Another aim of this study was to characterize, through multiple regression analysis, the relationship between blood pressure, body mass index, and cell sodium and potasssium. Higher RBC-Na and WBC-Na were observed in essential hypertensives and normotensives with familial hypertension versus normotensive controls without familial hypertension. Normotensives with familial hypertension had WBC-Na and RBC-Na that were not significantly different from those in essential hypertensives. RBC-K was not significantly different between normotensives with familial hypertension, normotensives without familial hypertension and essential hypertensives. WBC-K was not significantly different between normotensives with familial hypertension and essential hypertensives. Normotensives with familial hypertension had significantly higher WBC-K than normotensives without familial hypertension and essential hypertensives. Correlations that were significant in the combined normotensive-hypertensive group include: (i) The direct relationship between blood pressure (systolic, diastolic and mean) and RBC-Na and also WBC-Na. (ii) The inverse relationship between blood pressure (diastolic and mean) and RBC-K and WBC-K. (iii) The direct relationship between body mass index and WBC-Na and WBC-K. Correlations that were significant in the essential hypertensive group include: (i) The inverse relationship between blood pressure (diastolic and mean) and RBC-K and also WBC-K. (ii) The direct relationship between body mass index and WBC-Na. Most of these results are compatible with the hypothesis that sodium is involved in the pathogenesis of essential hypertension (AU)

The measurement of red blood cell deformability in health and disease

The deformability of the red blood cell was analysed into viscous, elastic and geometrical components and shown to be unidentifiable as a single measurable physical property. The measurement of deformability was then atttempted in three ways. Capillary traversal times of red blood cells were measured as an index of deformability. Osmotic swelling was shown to decrease deformability. Suggestions were made for overcoming the technical difficulties so as to allow for routine use of the method. The method seems to have considerable potential for investigating the effects of changes in deformability on flow in the micro-circulation. The relaxation time associated with recovery of shape (and orientation) of red cells was measured as an index of deformability. The results suggest that the recovery of shape is very rapid, < 1 s, and that thereafter the relaxation is of orientation and the cell behaves as a rigid disc. The method appears not to be useful. Measurements of apparent viscosity, shear rate, and cell volume fraction were made for suspensions of red cells and elastic and viscous parameters obtained based on modelling of the red cell as a liquid drop and as a viscoelastic sphere. The viscoelastic sphere theory was found to be a better description of red blood cell rheology than the liquid drop model, which was found to be unsuitable. Values of bulk cell viscosity and cell rigidity were obtained. The optimal hematocrit method was also employed and in this last method, microviscometry was used to extend the measurements to diseased states. No significant difference between samples from normal and diseased subjects were observed. It was found that the red cell is very fluid; the theory of red cell suspension viscosity undeveloped; and the accuracy of low viscosity microviscometers insufficient to measure small changes in viscosity (AU)

Sickle-cell anaemia in adults and its differentiation from sickle-cell thalassaemia

It is relatively easy in Jamaica to separate adult cases of sickle-cell anaemia from sickle-cell thalassaemia. We present evidence to show that the great majority of our 49 adult cases of sickle-cell anaemia had the true genotype SS. We have always been able to distiguish our cases of sickle-cell thalassaemia from those with sickle-cell anaemia before family studies. The blood morphology is appreciably different in the two diseases. We were able to prove in one family that patients with sickle-cell anaemia can reach adult life and have children. Our family studies in sickle-cell anaemia have also shown the presence of an S gene in all parents and in all children of SS homozygotes. In the two years of our study we have seen only three deaths in our series of 114 cases of sickle-cell anaemia. We think that in Jamaica the true natural history of the disease presents itself, whereas in Africa it may be obscured by parasitic and other tropical diseases. This will tend to eliminate early in life those whose resistance is weakened by severe anaemia. In sickle-cell thalassaemia at least three groups of patients could be distinguished, depending on the race of the parent who had contributed the thalassaemia gene.(AU)

An unusual type of hemoglobinopathy resembling sickle cell-thalassemia disease in a Jamaican family

Three generations of a Jamaican family of African extraction are desribed, in several members of which an abnormal gene is carried. This gene produces high levels of fetal hemoglobin unassociated with the usual stigmata of thalassemia. It is found in all three generations of the family associated with hemoglobin A only and is also found in at least two members of the family interacting with hemoglobin S. In the latter combination little or no disability results. The mode of inheritance of this abnormal gene is discussed, and reasons are put forward for a possible protective effect of high fetal hemogobin levels due to inhibition of sickling. The findings in the cord blood of the youngest child, including an unusually high percentage of sickling, are discussed, together with follow-up studies to the age of 25 weeks.(AU)