Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0240066 (iron deficiency)
 7,156 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Packed red cell volume (VPRC) and total blood volume chiefly affect oxygen transport to tissues and produce the syndrome of polycythemic hyperviscosity. Several studies have demonstrated that a raised VPRC increases the blood viscosity and, under a measured pressure, decreases the flow rate in a capillary tube. Reduced flow results in a less effective tissue perfusion. The oxygen transport at different values of VPRC is shown by an inverted arc-like curve: at normal VPRC levels the oxygen transport is optimal. Hypervolemia affects oxygen transport to tissues: at the same VPRC values, hypervolemic patients have a better oxygen transport. In polycythemia vera (PV), hypervolemia may partially reduce the damage due to the increased blood viscosity. However, in some local areas where fixed vessel diameter (from arteriosclerosis) limits the increased blood flow, hyperviscosity may result in a local tissue ischemia. A relative iron deficiency with associated microcytosis due to venesection frequently occurs in PV. It is also associated with a delayed red blood cell filtration which may contribute to hyperviscosity. When thrombocytosis is present, the risk of thrombotic complications is furthermore increased. We report symptoms and signs at the onset in a series of 80 patients affected by PV. All patients have a minimum follow-up of 4 years. We also report the course of the illness, the treatment effectiveness (venesection, dibromomannitol) on clinical symptoms, the survival curve with analysis of prognostic factors at the onset and the causes of death.
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PMID:[Polycythemic hyperviscosity syndromes]. 667 89

This article reviews selected nutrition research pertinent to adolescent health care. Protein--calorie malnutrition affects 25% of hospitalized adolescents studied, which correlates, as in adults, with increased morbidity and mortality. Some subgroups of adolescents, notably Asian immigrants, have been shown to be at high risk for developing vitamin D deficient rickets. On the other hand, excessive vitamin D intake has been linked to arteriosclerosis in animal models. Calcium supplementation is not likely to be indicated in U.S. adolescents. Iron deficiency prevalence in adolescence is not well documented, owing to the confusion between anemia and iron deficiency. Serum ferritin and free erythrocyte protoporphyrin measures should help to clarify this issue. Zinc nutrition must be assessed in high-risk groups such as those with short stature or Crohn's disease. Oral contraception effects on vitamin B6 and on serum lipids need to be considered in the risk-benefit equation when prescribing this method of birth control for adolescents.
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PMID:Nutrition and the adolescent: an update. 702 6