RESUMO
Infection with Streptococcus pyogenes, a Group A beta-hemolytic streptococcus (GAS), is a rare cause of hemolyticuremic syndrome (HUS). Invasive infections with Streptococcus pneumoniae that produce neuraminidase are a well-recognized cause of HUS without diarrhea. The Thomsen- Friedenreich antigen (T antigen) plays a role in the pathophysiology of pneumococcal HUS. We describe the case of a 3-year-old boy with GAS-associated HUS and show how T-antigen exposure was implicated in this case. He had no diarrhea and cultures for blood, urine, and stool were negative. The urinary pneumococcal antigen was negative; his direct Coombs test was positive. Glomerular capillary loops, tubular epithelium on his renal biopsy specimen, and red blood cells in his blood smear showed positive fluorescence with anti-T lectin. Although the pathogenesis of GAS-associated HUS is not well understood, T-antigen exposure may be implicated in some cases with GAS-associated HUS.
Assuntos
Antígenos Glicosídicos Associados a Tumores/imunologia , Síndrome Hemolítico-Urêmica/etiologia , Infecções Estreptocócicas/complicações , Streptococcus pyogenes , Pré-Escolar , Complemento C3/análise , Humanos , MasculinoRESUMO
We evaluated the pharmacokinetics of routinely administered bosentan in 46 Japanese pediatric patients with pulmonary arterial hypertension. Plasma samples were taken twice at times corresponding to the peak and trough concentrations following repetitive oral administration. The population pharmacokinetic parameters of bosentan were estimated by use of the NONMEM program, in which a one-compartment model with repetitive bolus dosing was parameterized in terms of the oral clearance (CL/F) and elimination rate constant (k). Polymorphisms of CYP3A5, SLCO1B1, SLCO1B3, and SLCO2B1 had no significant effect on the disposition of bosentan. In addition, the pharmacokinetics of bosentan was not altered by heart failure or coadministration of sildenafil. In contrast, weight (WT)-normalized values of CL/F were correlated negatively with age (AGE). The final population mean values of CL/F and k were estimated to be 0.409 · (1 - 0.0377 · (AGE - 3.81)) · WT L/h and 0.175 h(-1), respectively.