Diagnosis and monitoring of acute cytomegalovirus infection in peripheral blood of transplant recipients by nested reverse transcriptase polymerase chain reaction (RT-PCR).

The aim of this novel diagnostic approach is to monitor cytomegalovirus (CMV) infection in immunocompromised transplant recipients using early, sensitive, and specific predictors before and during antiviral therapy. The peripheral blood cells of 20 patients after transplantation (9 liver, 7 kidney, 4 simultaneous kidney-pancreas) were studied for an early diagnosis of acute infection. The mRNA and DNA of human CMV immediate-early antigen (IEA) were detected by nested-polymerase chain reaction (PCR) assay. Results of nested PCR were compared with the immunological detection of antigen pp65 and serological diagnosis of CMV infection. All data were correlated with clinical symptoms like leukopenia, thrombopenia, pneumonia, and allograft-rejection reaction. Of 20 transplant recipients, 12 were infected by CMV, and 9 suffered from a CMV-related disease. CMV mRNA were detected simultaneously with antigen pp65 and CMV DNA in all patients with symptomatic infection. Additionally, CMV mRNA was found over a longer period after ganciclovir treatment of infected recipients. Nested reverse transcriptase (RT)-PCR for CMV-IEA mRNA allows a sensitive and specific diagnosis of an acute CMV infection. CMV mRNA was found to be a good marker of acute viremia and could be a useful tool for CMV monitoring over the whole period of disease management, even during antiviral therapy.

Clinical enflurane metabolism by cytochrome P450 2E1.

BACKGROUND: Fluorinated ether anesthetic hepatotoxicity and nephrotoxicity are mediated by cytochrome P450-catalyzed oxidative metabolism. Metabolism of the volatile anesthetic enflurane to inorganic fluoride ion by human liver microsomes in vitro is catalyzed predominantly by the cytochrome P450 isoform CYP2E1. This investigation tested the hypothesis that P450 2E1 is also the isoform responsible for human enflurane metabolism in vivo. Disulfiram, which is converted in vivo to a selective inhibitor of P450 2E1, was used as a metabolic probe for P450 2E1. METHODS: Twenty patients undergoing elective surgery were randomized to receive disulfiram (500 mg orally; n = 10) or nothing (control subjects; n = 10) the evening before surgery. All patients received a standard anesthetic of enflurane (2.2% end-tidal) in oxygen for 3 hours. Blood enflurane concentrations were measured by gas chromatography. Plasma and urine fluoride concentrations were quantitated by ion-selective electrode. RESULTS: Patient groups were similar with respect to age, weight, gender, duration of surgery, and blood loss. Total enflurane dose, measured by cumulative end-tidal enflurane concentrations (3.9 to 4.1 MAC-hr) and by blood enflurane concentrations, was similar in both groups. Plasma fluoride concentrations increased from 3.6 +/- 1.5 mumol/L (baseline) to 24.3 +/- 3.8 mumol/L (peak) in untreated patients (mean +/- SE). Disulfiram treatment completely abolished the rise in plasma fluoride concentration. Urine fluoride excretion was similarly significantly diminished in disulfiram-treated patients. Fluoride excretion in disulfiram-treated patients was 62 +/- 10 and 61 +/- 12 mumol on days 1 and 2, respectively, compared with 1090 +/- 180 and 1200 +/- 220 mumol in control subjects (p < 0.05 on each day). CONCLUSIONS: Disulfiram prevented fluoride ion production after enflurane anesthesia. These results suggest that P450 2E1 is the predominant P450 isoform responsible for human clinical enflurane metabolism in vivo.

A prospective study of intraoperative pulse oximetry failure.

Since pulse oximetry is now an ASA standard for intraoperative monitoring, we sought to determine the intraoperative failure rate for this device. We prospectively evaluated the intraoperative failure rate of our pulse oximeters at the four University of Washington Hospitals (University of Washington Medical Center, Veterans Affairs Medical Center [VAMC], Children's Hospital and Medical Center, and Harborview Medical Center [HMC]) recorded from April 1989 to August 1989. We defined failure as the inability to obtain any oximetry reading for a cumulative period of more than 30 minutes during any anesthetic procedure after all equipment malfunctions had been eliminated. Our puse oximeters failed in 124 of 11,046 cases studied; this is a failure rate of 1.12%, which ranged from 0.56% at HMC to 4.24% at VAMC. The failure rate at VAMC (4.24%) was significantly higher than the other hospitals (p less than 0.001). Those cases associated with the pulse oximeter failure had the following characteristics: (1) an ASA status of 3 or higher, (2) lengthy operations, and (3) elderly patients. When the device did fail in a patient, it did not function for 32% of the mean anesthesia time. We conclude that the intraoperative use of the pulse oximetry can provide information about blood oxygen saturation in most patients. However, in approximately 1% of the patients we studied in the operating room, mechanically functioning pulse oximeters failed to provide readings of blood oxygen saturations during routine operative use.