RESUMO
Twenty-three unselected hemodialysis patients with functioning access arteriovenous fistulae were studied prospectively to determine the best technique for detecting stenoses within the fistulae. Combined clinical assessment and fistula assessment monitoring were compared with transbrachial angiography. Fistula assessment monitoring was more accurate (96%) than combined clinical assessment (accuracy, 52%) in stenosis detection. Complications of angiography occurred in 17% of patients; there were no complications of fistula assessment monitoring. Fistula assessment monitoring was better than combined clinical assessment in predicting clinical outcome for arteriovenous fistulae over 6 months and was as good as angiography. Routine fistula assessment monitoring could reduce inappropriate angiography and detect clinically significant silent stenoses. It is an ideal method for monitoring arteriovenous access fistulae.
Assuntos
Angiografia/métodos , Derivação Arteriovenosa Cirúrgica , Monitorização Fisiológica/métodos , Trombose/diagnóstico , Angiografia/efeitos adversos , Pressão Sanguínea , Estudos de Coortes , Humanos , Estudos Prospectivos , Fluxo Sanguíneo Regional , Diálise Renal , Grau de Desobstrução VascularRESUMO
Changes in the metabolism of zinc were investigated in mature nonlactating Holstein cows and 4-mo old calves fed high but nontoxic amounts of dietary zinc. Increasing dietary zinc of calves from 42 to 642 ppm elevated the zinc content of liver and pancreas 600% and 1400%, respectively. The elevated zinc in liver and pancreas involved a substantial increase in all intracellular fractions, with by far the largest amount associated with a 10,000 molecular-weight protein in the soluble cell fraction. This zinc-binding protein may protect the cell against damage from increased zinc. A comparable increase in dietary zinc of mature cows did not affect zinc content of liver or kidney nor alter the intracellular distribution of zinc in the liver. In mature cows, homeostatic control mechanisms which regulate the zinc content of tissue are much more effective than in calves. Accordingly, mature cows probably are able to tolerate higher concentrations of dietary zinc.