Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019045 (hemoglobinopathies)
 2,704 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Regional cerebral blood flow (rCBF) was measured in 16 cranial regions in 23 children and adolescents with frequent headaches using the non-invasive Xenon-133 inhalation technique. Blood flow response to 5% carbon dioxide (CO2) was also determined in 21 patients, while response to 50% oxygen was measured in the two patients with hemoglobinopathy. Included were 10 patients with a clinical diagnosis of migraine, 4 with musculoskeletal headaches, and 3 with features of both types. Also studied were 2 patients with primary thrombocythemia, 2 patients with hemoglobinopathy and headaches, 1 patient with polycythemia, and 1 with headaches following trauma. With two exceptions, rCBF determinations were done during an asymptomatic period. Baseline rCBF values tended to be higher in these young patients than in young adults done in our laboratory. Localized reduction in the expected blood flow surge after CO2 inhalation, most often noted posteriorly, was seen in 8 of the 13 vascular headaches, but in none of the musculoskeletal headache group. Both patients with primary thrombocythemia had normal baseline flow values and altered responsiveness to CO2 similar to that seen in migraineurs; thus, the frequently reported headache and transient neurologic signs with primary thrombocythemia are probably not due to microvascular obstruction as previously suggested. These data support the concept of pediatric migraine as a disorder of vasomotor function and also add to our knowledge of normal rCBF values in younger patients. Demonstration of altered vasomotor reactivity to CO2 could prove helpful in children whose headache is atypical.
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PMID:Regional cerebral blood flow in childhood headache. 250 64

Hydroxyurea (HU) has been used in patients with essential thrombocythemia (ET) to reduce the frequency and severity of thrombotic complications of the disease. It acts by causing bone marrow depression, resulting in a decrease in platelet and leukocyte counts and in anemia with megaloblastosis. Herein we report a case of an 80-year-old man with ET who developed severe hemolytic anemia requiring multiple packed RBC transfusions while being treated with HU. The hemolysis persisted until discontinuation of the drug. This case suggests hemolysis as a potential side effect of HU and raises the clinical concern that not all HU-induced anemia is secondary to erythropoiesis depression. With the increasing use of HU in the management of ET, hemoglobinopathy, and other diseases, the importance of monitoring for hemolysis must be further emphasized in these patients.
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PMID:Hydroxyurea-induced hemolytic anemia in a patient with essential thrombocythemia. 1555 7

PATHOPHYSIOLOGY OF PULMONARY ARTERIAL HYPERTENSION IS BASED ON THREE BASIC MECHANISMS: thrombotic pulmonary vascular lesions, vasoconstriction and vascular remodeling. Platelets are related to all of these mechanisms by their aggregation, production, storage and release of several mediators. The role of platelets is more prominent in some types of pulmonary arterial hypertension, including those which are secondary to inflammatory and infectious diseases, hemoglobinopathies, essential thrombocythemia, drugs, thromboembolism, and cardiac surgery. Most pulmonary antihypertensive drugs have a negative effect on platelets. In this review, the mechanisms of platelets association with pulmonary arterial hypertension, those types of pulmonary arterial hypertension with greatest platelet contribution to their pathophysiology, and the effects of pulmonary antihypertensive drugs on platelets are summarized.
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PMID:Platelets in pulmonary hypertension: a causative role or a simple association? 2305 79