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Biomedical subjects

E B Schoomaker

Publications and source records attributed to E B Schoomaker.

28 records · Page 2Linked to original sources
PubMed1976

Trace elements in sickle cell disease.

Trace elements in 84 adult patients (38 men and 46 women) with sickle cell disease (SCD) were reflected in clinical and biochemical data. Height was retarded in six men and five women. Eighty percent of the SCD patients in this sample were below the 50th percentile from the normal mean for weight. Twenty-eight men showed a lack of facial and body hair, and five additional subjects showed only scanty facial hair. Whereas zinc in plasma, red blood cells, and hair was decreased, the excretion of zinc in urine was increased in SCD patients as compared to the controls. We believe that one of the mechanisms accounting for zinc deficiency in SCD may be hyperzincuria and that growth retardation and hypogonadism in men so commonly seen in SCD may be related to zinc deficiency.

Adolescent↗
PubMed1976

Zinc in the treatment of homozygous sickle cell anemia: studies in an animal model.

We have studied the effects of zinc on the 51Cr survival of red blood cells (RBC) from patients with homozygous sickle cell anemia (SCA) using an animal model in which the RBC were transfused into specially prepared rats. The slope (lambdas) of a standard 51Cr RBC survival curve was used as a measure of the rate of RBC sequestration. The effects of intravenous zinc were of considerable therapeutic interest from the standpoint of setting guidelines for effective blood levels of zinc in patients. SCA RBC were transfused into rats whose plasma zinc levels had been raised 3-6 times above normal (300-600 mug/100 ml) by prior iv injection of zinc acetate; in three experiments the mean lambdas in zinc-treated animals breathing 15-16% oxygen was significantly lower (meaning lessened sequestration and greater survival) than saline-treated controls. A possible explanation for the requirement to lower ambient oxygen tension in order to see this zinc effect is discussed. We have further observed an increased mean lambdas for RBC from 10 SCA patients compared to 4 normal controls (0.134 vs 0.030; t = 2.8, p less than 0.01). The lambdas values are quite patient specific (4 patients studied; F = 18.2, P = 0.002). In vitro pretransfusion treatment of SCA RBC with 1.5 mM zinc resulted in a significant increase in hemoglobin oxygen affinity and a marked reduction in lambdas (0.073 vs 0.120; t = 4.5, p less than 0.01). The mean lambdas was not affected by in vitro 0.3 mM zinc treatment; this level did not change hemoglobin oxygen affinity. We conclude that systemic zinc therapy in the animal model described, at plasma levels only slightly higher than those presently obtained in patients, prolongs SCA RBC survival. This animal model is a sensitive measure of the sicklability of SCA RBC and is useful in the testing of in vitro and in vivo antisickling agents.

Anemia, Sickle Cell↗
PubMed1975

Zinc deficiency in sickle cell disease.

Clinical similarities between patients with sickle cell anemia and zinc-deficient subjects suggested a secondary zinc deficiency in sickle cell anemia. Zinc was assayed in various biological fluids and tissues by atomic absorption spectrophotometry. Zinc in the plasma, erythrocytes, and hair was decreased and urinary zinc excretion was increased in anemia patients as compared to controls. Erythrocyte zinc and daily urinary zinc excretion were inversely correlated in the anemia patients (r equal to minus .63, P smaller than 0.05), suggesting that hyperzincuria may have caused zinc deficiency in these patients. Carbonic anhydrase, a zinc metalloenzyme, correlated significantly with erythrocyte zinc (r equal to plus 0.94, P smaller than 0.001). Plasma RNase activity was significantly greater in anemia subjects than in controls. We administered zinc sulfate, 660 mg per day, orally, to seven men and two women with sickle cell anemia. Two 17-year-old males gained 5 cm and 7 cm in height during 49 and 42 weeks of zinc therapy, respectively. All but one patient gained weight (0.5 kg to 4.1 kg). Five of the males showed increased growth of pubic, axillary, facial, and body hair, and in one a leg ulcer healed in six weeks on zinc and in two others some benefit of zinc therapy on healing of ulcers was noted.

Adolescent↗