Therapeutic drug monitoring of the HIV/AIDS drugs abacavir, zidovudine, efavirenz, nevirapine, indinavir, lopinavir, and nelfinavir.

Combination therapy with antiretroviral drugs is used for the treatment of patients infected with the human immunodeficiency virus. To achieve optimal drug concentrations for viral suppression and avoidance of drug toxicity, monitoring of drug levels has been considered essential. We set up an analytical procedure for monitoring the plasma concentrations of a total of seven drugs: abacavir, zidovudine, efavirenz, nevirapine, indinavir, lopinavir, and nelfinavir. The plasma samples were liquid/liquid extracted and subjected to high-performance liquid chromatography (HPLC) analysis. The compounds were monitored by ultraviolet detection: indinavir, lopinavir, and nelfinavir at 215 nm; efavirenz at 254 nm, and abacavir, zidovudine, and nevirapine at 266 nm. Two different extraction procedures and two different HPLC eluents on a C(8) reversed-phase HPLC column were used to monitor all seven compounds. Under steady state conditions, the plasma concentrations of antiviral drugs in 175 patients were correlated with the time after the last dosing to define the peak or trough levels. Due to the short plasma elimination half-life of abacavir and zidovudine, only peak levels could be determined for these compounds, whereas both peak and trough levels could be assessed for the other compounds because of a longer plasma elimination half-life. The mean peak concentrations (microg/ml) were 0.69 for abacavir and 0.57 for zidovudine; the mean peak/trough concentrations (microg/ml) were 2.07/1.32 for efavirenz, 2.43/2.23 for nevirapine, 5.48/1.08 for indinavir, 4.69/3.51 for lopinavir, and 3.54/1.45 for nelfinavir. The described analytical method offers a broad-spectrum monitoring of plasma levels of antiretroviral drugs.

Quantitation and genotyping of hepatitis C virus RNA in sera of hemodialysis and AIDS patients.

BACKGROUND: Hepatitis C virus (HCV) infection is highly prevalent in hemodialysis and AIDS patients. Little information exists about the viral load in those patients. OBJECTIVE: To characterize HCV infection in hemodialysis and AIDS patients, the viral load in the sera was measured. Results were compared with genotypes, gender of the patients, and biochemical markers of active hepatitis. STUDY DESIGN: Sera from a total of 442 patients were screened with a third-generation EIA, and anti-HCV immunoreactivity was confirmed with the Wellcozyme HCV Western Blot. After qualitative PCR with the Amplicor PCR Test, positives were genotyped using a reverse hybridization test. Determination of HCV levels was done with the Amplicor HCV Monitor assay. RESULTS: HCV RNA was detected in the sera of 95 (74.8%) EIA-positive patients. HCV RNA levels ranged from 1 x 10(4) to 1.4 x 10(6) molecules of HCV RNA/ml. Median HCV RNA levels of AIDS patients were slightly higher than those of hemodialysis patients. Male patients had higher median HCV RNA levels compared with female patients. No association between HCV RNA levels and both alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels was found. The most common genotypes were type 1b and type 1a, followed by type 3, type 4, and type 2a. There were no significant differences in HCV RNA levels among patients with genotypes 1a, 1b, and 2a. Patients infected with types 3 and 4, respectively, had significantly lower HCV RNA levels compared with other genotypes. CONCLUSION: Because the Amplicor HCV Monitor assay allows quantitation of low-titer viremic patients, HCV RNA levels were distinctly lower compared with previous reports. HCV RNA levels of males did not differ significantly from those of females. ALT and AST are very poor indicators of ongoing HCV infection. Patients with chronic type 3 or type 4 HCV infection tended to have lower HCV RNA levels.

Detection of hepatitis C viral sequences in serum by 'nested' polymerase chain reaction (PCR) and a commercial single-round PCR assay.

BACKGROUND: Demonstration of the hepatitis C virus (HCV) genome is usually done with combined reverse transcription and polymerase chain reaction (RT-PCR) employing nested primer sets. Recently, a commercial PCR assay (Amplicor PCR assay), based on a simplified sample preparation procedure, a single, combined reverse transcription and polymerase chain reaction (RT-PCR), and a microwell plate capture and detection, has been developed. OBJECTIVE: The aim of the present study was to compare the new Amplicor assay with an 'in-house' PCR. Additional testing included a third-generation enzyme immunoassay for anti-HCV antibodies, the Wellcozyme HCV Western Blot, which is equivalent to a third-generation recombinant immunoblot assay. Furthermore, HCV genotypes were classified. STUDY DESIGN: Sera from a total of 127 patients were studied. After screening with a third-generation enzyme immunoassay (EIA), the Wellcozyme HCV Western Blot, was performed as well as the conventional RT-PCR and the Amplicor PCR. Specimens, which were found positive by testing with the Amplicor kit, were subjected to storage at room temperature for 96 h. RESULTS: A total of 52 patients were found to be positive for anti-HCV by the third-generation EIA. With the Amplicor assay, the HCV genome was detected in 38 patients. In comparison with the 'in-house' assay, two discrepant results were found. Resolution of discrepant samples increased the total number of true positives to 39. A good correlation was found between a positive anti-HCV test result and the presence of HCV-RNA by RT-PCR. No significant reduction in the amount of amplification product was observed by retesting of suboptimally stored samples with the Amplicor assay. CONCLUSION: Because of the rapidity and the improved ease of handling, the Amplicor assay was found to be a good contribution for detection of HCV in serum.

[Extracorporeal shockwave therapy in giant stones in the common bile duct--a case report]. / Extrakorporale Stosswellentherapie bei Riesenkonkrement im Ductus choledochus--Ein Fallbericht.

A huge common bile duct stone of 6 to 3 cm in diameter in a 64 year old lady was approached by ESWL, after endoscopic therapy such as mechanical lithotripsy and removal with the Dormia basket had failed because of the extraordinary size of this stone. A surgical therapy was not possible because of pronounced vascular and cardiopulmonary risk, so ESWL was applied to this patient. The stone was fragmented in two sessions of ESWL under sonographic targeting and the fragments were removed endoscopically. After one month one fragment still remained in the common bile duct, which then was removed also endoscopically. Two months later the ERC showed a stone-free common bile duct. This case demonstrates, that even common bile duct stones of extraordinary size can be removed by combining ESWL with endoscopic techniques. Following the trend to minimally invasive therapy, sonography should be preferred over XRay in diagnosis before ESWL as well as during ESWL.