Left ventricular performance during and after sickle cell crisis

Although microvascular occlusion has been considered a basis for pathophysiology of the myocardium during the crisis of sickle cell anemia, the status of the left ventricle in uncertain. To determine if left ventricular performance is affected by crisis, 11 patients were evaluated noninvasively by the systolic time interval method on the first day of crisis and serially until recovery. There were no significant differences in the time intervals over this period. In addition, since the serum CPK-MB isoenzyme was not elevated during crisis and evidence of acute injury was not present on ECG, myocardial necrosis appeared unlikely. Four patients on subsequent admission exhibited systolic time interval values similar to the earlier crisis. To determine if there were chronic changes in cardiac function, subjects with sickle cell hemoglobin were studied between crises. Those under 23 years of age were not dissimilar from a group of normals and a group of patients with chronic blood loss anemia A significant abnormality of the PEP/LVET ratio was observed in subjects over 23 years of age. Similar observations were made on echocardiography, with subjects over the age of 23 demonstrating an abnormal ejection fraction compared to the younger group, despite enhanced end-diastolic diameter. Thus, it is suggested that the chronic hemolytic process in subjects with sickle cell anemia may effect cumulative myocardial alterations, resulting in chronic cardiac malfunction in the apparent absence of acute ischemia during crises.

Properties of a membrane-bound phosphatase activity in normal and abnormal red blood cells

A neutral, membrane-bound, phosphatase activity was characterized in normal red blood cells, using p-nitrophenylphosphate as substrate. Its specific activity was 1.59 nmol mg-1 min-1. The kinetics were of the Michaelis type: KM,app = 2.5 X 10(-3) M. It was stimulated by K+ and inhibited by ouabain, a behaviour reminiscent of (Na+ + K+)-ATPase. In 10 patients with homozygous sickle cell disease and in 11 patients with unidentified congenital hemolytic anemias, the specific activity was significantly increased. In general, the phosphatase retained Michaelis-Menten kinetics. However, in four patients from the same family with an unidentified hemolytic anemia, the kinetics yielded a biphasic curve instead of a rectangular hyperbola, a change consistent with the existence of an inhibition by substrate excess. From detailed analysis of the curve, the apparent inhibitor constant for pNPP was determined: Ki,app approx. 2.5 X 10(-2) M. This novel abnormality of the red cell membrane might be the distinctive feature of a given type of congenital hemolytic anemia.

Human red blood cell membrane adenylate cyclase in sickle-cell disease

The basal and the NaF-stimulated activities of human red blood cell membrane adenylate cyclase were found to be 5.3 +/- 0.8 (SE) and 219 +/- 76 (SE) pmol . mg-1 . min-1, respectively. Both activities were increased in nine patients with homozygous sickle-cell disease. There was no apparent correlation between this increase and the increase in the reticulocyte count.

Serum-alpha-hydroxybutyrate dehydrogenase levels in sickle-cell disease and sickle-cell crisis

In patients with sickle-cell disease (Hb S/S disease) who are not in crisis, the serum-level of alpha-hydroxybutyrate dehydrogenase (alpha-H.B.D.) is significantly above normal. The degree of elevation correlates with the severity of the disease. During infarctive crises the level increases still further by a factor of 2 to 3, and it returns to the patient's normal level on recovery. The level of alpha-H.B.D. thus provides an index of the severity of the disease. Also, it allows distinction between true infarctive crisis, infection, and fake symptoms. In 5 patients a rise in the level of alpha-H.B.D. above the patient's normal level was detected several days before the onset of symptoms, which suggests that there may be a "prodromal" phase.

Hepatic bilirubin UDP-glucuronyltransferase in patients with sickle cell anemia

In sickle cell anemia the shortened survival of red blood cells presents the liver with an augmented load of bilirubin for hepatic clearance. To determine the effects of this excessive bilirubin load on the microsomal conjugating enzyme, hepatic bilirubin UDP-glucuronyltransferase, levels of this enzyme were measured in liver biopsies from patients with sickle cell anemia and several comparison groups. UDP-glucuronyltransferase activity in 14 patients with sickle cell anemia was 2-fold greater (P less than 0.005) than in 14 nonjaundiced comparison patients without liver disease. The elevated UDP-glucuronyltransferase activity in sickle cell anemia was similar to that found in 10 patients who chronically ingested drugs (barbiturates or estrogens) known to increase UDP-glucuronyltransferase activity. These observations suggest enhanced conjugation of bilirubin in patients with sickle cell anemia may result from substrate (bilirubin) induction of UDP-glycuronyltransferase.

Heme synthesis in hereditary hemolytic anemias: decreased delta-aminolevulinic acid synthetase in hemoglobin Köln disease

The activities of delta-aminolevulinic acid (ALA) synthetase and ALA dehydratase in cord blood erythrocytes of newborn infants and peripheral blood red cells of patients with beta-thalassemia major, beta-thalassemia intermedia, hemoglobin Köln (Hb Köln) disease, sickle cell anemia, and pyruvate kinase deficiency were studied. The activity of ALA dehydratase did not vary appreciably with the number of immature RBC (reticulocytes and nucleated red blood cells) or the severity of the hemolytic anemia except in pyruvate kinase deficiency. The activity of ALA synthetase was linearly correlated with the number of immature RBC (r=0.974, p is less than 0.001). The ALA synthetase activity was significantly decreased in the RBC of Hb Köln (p is less than 0.01) when compared with the activity in immature RBC of newborns and of patients with pyruvate kinase deficiency, sickle cell anemia, and thalassemia intermedia.

Serum alkaline phosphatase isoenzymes in sickle cell anemia

Alkaline phosphatase isoenzymes in sera from patients with sickle cell anemia were separated by electrophoresis on starch gel. Physical and biochemical criteria identified bone alkaline phosphatase as the principal, although not necessarily the sole, enzyme fraction that increases during symptomatic sickle cell crises. Moreover, there appeared to be concordance between crisis severity, serum levels of alkaline phosphatase, and isoenzyme patterns; electrophoretic and biochemical abnormalities could be detected even when the patients were asymptomatic. The present data suggest that the serum alkaline phosphatase level may be an additional indicator of the degree, frequency, and persistence of tissue injuries that occur in sickle cell anemia.