Intracellular free magnesium of red blood cells in patients with renal disease.

While serum magnesium (Mg) level is increased in patients with end-stage renal disease (ESRD), it is decreased in renal transplant recipients (TR) receiving ciclosporin. This study was performed to examine the cation metabolism of red blood cells (RBC) in these patients. Intracellular free Mg was measured with 31P-nuclear magnetic resonance spectrometry, and ouabain-sensitive sodium (Na) efflux rate (Eos) was measured from the increase in RBC-Na concentration when RBC were incubated in the presence of ouabain. The ouabain-sensitive Na efflux rate constant (ERCos) was obtained by dividing Eos by RBC-Na concentration. RBC free Mg and ERCos were significantly higher in the TR group than in the ESRD group. There was a significant correlation between RBC free Mg and ERCos (r = 0.474, p less than 0.01). These results support the views that the regulation mechanism for intracellular free Mg is different from that for extracellular Mg in patients with renal disease, and intracellular free Mg modulates Na pump activity of RBC.     

Alcohol drinking and high blood pressure: data from a 1980 national cardiovascular survey of Japan.

Many epidemiological cross-sectional studies have confirmed that alcohol drinking is related to high blood pressure. However, the impact of alcohol drinking on high blood pressure in the general population including older people has only been reported on in a few studies. The association between alcohol drinking and blood pressure or the prevalence of hypertension was examined using cross-sectional data of 4795 men and 6102 women aged 30-94, randomly selected from the Japanese population in 1980. The response rates were 74 and 84% for men and women, respectively. The prevalence of hypertension adjusted for body mass index (BMI, kg/m2) was significantly higher in everyday male drinkers than in male non-drinkers from the youngest age group (30-39 years) to oldest age group (70 years and over). A relationship between alcohol and blood pressure was found only in the youngest age group (30-39 years) of female drinkers. In each 10-year age-group of men, the BMI-adjusted systolic and diastolic blood pressures in everyday drinkers were 7-10 and 4-6 mmHg higher than those in non-drinkers. The relationship between alcohol and blood pressure in men was confirmed by multiple regression analysis adjusting for age and BMI in both younger (30-59 years) and older (60-94 years) people. The impact of alcohol drinking on blood pressure in men should be taken into account in the primary prevention of blood pressure related diseases and in the treatment of hypertension in both younger and older people.     

Gorog Thrombosis Test: analysis of factors influencing occlusive thrombus formation.

We used the Gorog Thrombosis Test to analyze the factors influencing the occlusion time, which represents platelet activation and subsequent occlusive thrombus formation, in 132 healthy Japanese volunteers (116 men, 16 women; mean age, 45.0 +/- 12.0 years). The Gorog Thrombosis Test was designed to evaluate platelet aggregation and thrombolytic activity under a high shear stress condition (175 dynes/cm) in a native blood sample in vitro. The mean +/- SD occlusion time was 154.8 +/- 64.7 s (men, 153.4 +/- 64.2 s and women, 165.4 +/- 56.5 s). The occlusion time was inversely correlated with von Willebrand factor ristocetin cofactor activity (VWF:Rco) (r = -0.242, P = 0.0055) and von Willebrand factor antigen (r = -0.230, P = 0.0080). The mean occlusion time in the group with VWF:Rco of at least 170% (137 s) was significantly shorter than that in the group with VWF:Rco less than 170% (156 s, P < 0.05). Platelet counts, other coagulation markers and smoking showed no significant correlations with occlusion time. Red blood cells (r = -0.177, P = 0.0365), hemoglobin (r = -0.191, P = 0.0245) and hematocrit (r = -0.182, P = 0.0329) also showed inverse correlations with the occlusion time. This report is the first to clearly demonstrate the role of von Willebrand factor in the formation of occlusive thrombi in the Gorog Thrombosis Test.     

Antihypertensive effect of E-643, a new alpha-adrenergic blocking agent

Summary To determine whether E-643, a new -blocking agent, would reduce the blood pressure, regardless of the posture, a 1 mg dose was given 3 times daily for 7 consecutive days, to 8 male and 7 female inpatients, aged 37–73 years, with essential hypertension. Blood pressure and pulse rate were measured daily in the supine, sitting and standing positions. Before and after the treatment with E-643, plasma levels of noradrenaline, adrenaline, dopamine--hydroxylase, renin and aldosterone were determined, samples being obtained with the subjects recumbent and after standing upright for 60 min. A significant reduction in the systolic and diastolic blood pressures was evident in the supine (172±31/100±12 151±28/89±14 mmHg), sitting (158±22/101±11 138±28/89±15 mmHg) and standing (153±32/103±21 129±31/89±20 mmHg) positions. The reduction in blood pressure remained unchanged throughout the period of administration of E-643. Pulse rate was not affected when the subjects were supine (67±10 69±10 beats/min), but was increased in the sitting (68±10 73±9 beats/min) and standing (73±10 81±11 beats/min) positions. The increased pulse rate tended to decline during continued administration of E-643. Treatment with E-643 produced no significant change in plasma levels of adrenaline, noradrenaline, dopamine--hydroxylase, renin and aldosterone. The antihypertensive effect of treatment was more prominent in the patients with higher levels of plasma catecholamines and dopamine--hydroxylase, and was less prominent in those with higher plasma renin and aldosterone. Two patients had temporary bouts of dizziness and visual disturbances, but there were no subjective complaints during treatment.     

Factors influencing arterial oxygenation early after bidirectional cavopulmonary shunt without additional sources of pulmonary blood flow

OBJECTIVES: Although the arterial oxygen saturation after bidirectional cavopulmonary shunting should theoretically be homogeneous if additional pulmonary flow is obliterated, the arterial oxygen saturation has been found to vary in clinical practice. Knowledge of the preoperative and operative determinants of arterial oxygen saturation early after bidirectional cavopulmonary shunting may lead to a better understanding of this unique physiology. METHODS: Thirty-five patients who underwent bidirectional cavopulmonary shunting with obliteration of additional pulmonary flow were included in this study. The arterial oxygen saturation was determined at the 5 time points over a 48-hour period. Multivariable regression analysis was used to identify the independent predictors of the arterial oxygen saturation. RESULTS: No significant interval changes occurred in the arterial oxygen saturation during the 48 hours after bidirectional cavopulmonary shunting, which ranged from 61.6% to 95.6%. There was a significant inverse correlation between the postoperative superior vena cava pressure and the arterial oxygen saturation (P =.003). A low arterial oxygen saturation early after bidirectional cavopulmonary shunting was a predictor of mortality or exclusion from univentricular repair within 24 months (P =.012, odds ratio = 1.14). Of 11 factors identified by univariable analysis, multiple regression analysis indicated that age less than 8 months at the time of shunting (P <.0001) and ventricular volume overload (P =. 002) predicted a lower arterial oxygen saturation after bidirectional cavopulmonary shunting. CONCLUSIONS: Even without additional sources of pulmonary blood flow, several preoperative factors, including younger age and severe ventricular volume overload, predicted a decrease in the arterial oxygen saturation early after bidirectional cavopulmonary shunting. This, in turn, predicted poor outcome during 2 years of follow-up.     

Acute depressor effect of alcohol in patients with essential hypertension.

To investigate the time course of the effects of alcohol on blood pressure, we studied the response of ambulatory blood pressure, neurohumoral variables, and hemodynamics to a single moderate dose of alcohol in hypertensive patients. Sixteen Japanese men (22-70 years old) with essential hypertension who were habitual drinkers were examined under standardized conditions. On the alcohol intake day, they ingested 1 ml/kg ethanol (vodka) at dinner, and on the control day they consumed a nonalcoholic beverage. The order of the two periods was randomized. Mean ambulatory blood pressure was lower in the alcohol intake period than in the control period (125 +/- 3/74 +/- 2 versus 132 +/- 4/78 +/- 2 mm Hg, p less than 0.05), and the significant depressor effect of alcohol lasted for up to 8 hours after drinking. Blood pressure on the next day did not differ with or without alcohol intake. The acute hypotensive effect of alcohol was associated with an increase in heart rate and cardiac output and with a decrease in systemic vascular resistance as determined by echocardiography. Plasma catecholamine levels and renin activity rose significantly at 2 hours after dinner, whereas vasopressin and potassium levels fell on the alcohol day. Blood glucose and serum insulin levels were comparable between the two periods. Three patients with marked alcohol-induced flush had greater hypotensive and tachycardiac responses than those who did not show an alcohol-induced flush. The change in mean blood pressure induced by alcohol was negatively correlated with age, the baseline blood pressure, and the change in plasma norepinephrine. These results indicate that the major effect of acute alcohol intake is to lower blood pressure through systemic vasodilatation in hypertensive subjects. Ambulatory blood pressure monitoring may be useful for assessing blood pressure in habitual drinkers.     

Effect of ramipril, a new angiotensin converting enzyme inhibitor, on diurnal variations of blood pressure in essential hypertension

The effect of ramipril on diurnal variations of blood pressure was studied in patients with mild to moderate essential hypertension in groups given once- (n = 18) and twice-daily (n = 21) administration with daily dosages ranging from 2.5 to 10 mg. After ramipril treatment, the blood pressure of patients in both groups was significantly reduced, and no significant differences in diurnal variation of blood pressure were observed between the 2 groups. The pulse rate did not change after administration of ramipril and no serious side effects were observed. In consideration of patient compliance, once-daily administration of ramipril seems to be optimal for the treatment of essential hypertension.