RESUMO
Although there are many reports providing evidence for platelet hyperactivity during acute infarctive crisis in sickle cell disease, little attention has been paid to the study of platelet release reaction in steady state. Plasma levels of the alpha-granule constituents beta-thromboglobulin and platelet factor 4 were measured in patients with sickle cell anemia during steady state and vaso-occlusive crisis in order to determine in vivo platelet activity. Significantly higher plasma levels of both proteins were found in steady state and in crisis when compared with those of normal controls. Platelet hyperactivity was also found to be more vigorous in painful crisis, suggesting a possible therapeutic role for drugs that inhibit platelet function.
Assuntos
Anemia Falciforme/sangue , Plaquetas/fisiologia , Doenças Vasculares/etiologia , Adulto , Anemia Falciforme/complicações , Humanos , Contagem de Plaquetas , Fator Plaquetário 4/metabolismo , Valores de Referência , beta-Tromboglobulina/metabolismoRESUMO
The effect of hydrocortisone on plasma theophylline concentrations was evaluated in 20 patients suffering from chronic bronchitis or stable bronchial asthma. Choline theophyllinate (400 mg) was orally administered every 12 h for 8 days and blood samples were taken every 2 h during the day for the measurement of theophylline concentrations. Intravenous bolus injections of 500 or 1000 mg hydrocortisone on day 5 or day 7, respectively, did not significantly alter plasma theophylline concentrations.
Assuntos
Hidrocortisona/farmacologia , Teofilina/farmacocinética , Adulto , Idoso , Asma/tratamento farmacológico , Preparações de Ação Retardada , Feminino , Humanos , Pneumopatias Obstrutivas/tratamento farmacológico , Masculino , Pessoa de Meia-Idade , Teofilina/sangue , Teofilina/uso terapêuticoRESUMO
To evaluate the platelet function in sickle cell syndromes we measured the beta-thromboglobulin (beta-TG) and platelet factor 4 (PF-4) plasma values of 45 patients suffering from homozygous sickle cell anaemia (10) and sickle cell beta-thalassaemia (35) in steady state. The results were compared to those of 32 normal controls. Both the beta-TG and PF-4 levels were found to be significantly higher in patients than in controls but the beta-TG:PF-4 ratio was significantly lower in the patients group. This finding and the absence of any statistical correlation between platelet number and beta-TG or PF-4 indicate that platelets seem to be somehow activated in sickle cell syndromes, both in homozygotes and sickle cell/beta-thalassaemia heterozygotes. This platelet activation seems to exist even in steady state sickle cell disease patients, regardless of the functional status of the spleen.
Assuntos
Anemia Falciforme/metabolismo , Fator Plaquetário 4/análise , beta-Tromboglobulina/análise , Adolescente , Adulto , Idoso , Anemia Falciforme/genética , Feminino , Heterozigoto , Homozigoto , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
Using a simplified competitive protein-binding assay, we measured serum 25-hydroxycholecalciferol (25-OH-D3) in 52 patients with chronic renal failure and in 21 normal subjects. Of the patients with chronic renal failure, 21 were undergoing hemodialysis. Low serum levels of 25-OH-D3 were found in nondialysis patients and normal levels in the dialysis group. A positive relationship between the levels of 25-OH-D3 and serum calcium and a negative relationship between the levels of 25-OH-D3 and serum creatinine were found in the nondialysis group. We postulate that the decreased 25-OH-D3 levels in chronic uremics is the result of the low level of vitamin D in their protein-restricted diets.