RESUMO
Improved and reliable methods for assessing glomerular filtration rate (GFR) in intensive care patients are needed in light of known deficiencies using creatinine clearance. We compared simultaneous two-hour clearances of inulin (CIn), creatinine (CCr), and 99mTc-diethylenetriaminepentaacetic acid (CDTPA) in 18 medical or surgical intensive care patients (range, 49 to 92 years old) with blood urea nitrogen (BUN) levels greater than 17.9 mmol/liter (0.5 mg/ml), serum creatinine levels greater than 150 mumol/liter (0.02 mg/ml), or estimated Cockcroft clearance less than 60 ml/min. Patients had severe renal dysfunction with average GFR of 35 ml/min (range, 2 to 69 ml/min). CDTPA and CCr correlated significantly with CIn, although CDTPA tended to provide a closer approximation. Cockcroft clearance (32 +/- 4 ml/min) was grossly similar to CDTPA and CIn and correlated significantly, especially when weight was calculated using actual as opposed to ideal body weight. In a subset of 13 patients with CIn less than 30 ml/min, only CDTPA was significantly correlated with CIn. In patients in the intensive care unit, CDTPA provides a rapid, accurate, and inexpensive clinical assessment of GFR, even at very low GFRs.
Assuntos
Taxa de Filtração Glomerular , Inulina , Pentetato de Tecnécio Tc 99m , Idoso , Idoso de 80 Anos ou mais , Creatinina/metabolismo , Feminino , Humanos , Unidades de Terapia Intensiva , Inulina/farmacocinética , Testes de Função Renal/métodos , Masculino , Taxa de Depuração Metabólica , Pessoa de Meia-Idade , Pentetato de Tecnécio Tc 99m/farmacocinéticaRESUMO
The efficiency of an electropositive filter for membrane chromatography of viruses was examined using coliform phages T1, T4, lambda and Salmonella phage P22. Phages diluted in dechlorinated tap water were adsorbed to filters at neutral pH and eluted by 3% beef extract in 0.05 M glycine buffer at selected alkaline pH values. With exception of lambda phage, which displayed erratic adsorption behavior at any pH, all bacteriophages studied, adsorbed to filters with an efficiency of 97-100% at pH values ranging between 6.0 and 8.0. Each phage was readily eluted at alkaline pH levels. Maximal elution (86.2%) of T1 phage and lambda phage (79%) occurred at pH 10, while T4 and Salmonella phages were eluted most efficiently at pH 11 at values of 91.7 and 81.9%, respectively. The resolving power of the filter was such that individual phages within the same virus group (T1 and T4 phage) could be eluted at pHs differing by only one unit.
