BACKGROUND Hepatitis C virus (HCV) cross-contamination from inanimate surfaces or objects has been implicated in transmission of HCV in health-care settings and among injection drug users. We established HCV-based carrier and drug transmission assays that simulate practical conditions to study inactivation and survival of HCV on inanimate surfaces. METHODS Studies were performed with authenti...

Figure 1. Process chart of feedback-driven hit generation. A random selection of molecules from the database initiates a cycle containing an assay, a learning and prediction step, and a selection of a new subset from the database. In case of an experimental in vitro assay, the selected compounds have to be synthesised. An in silico screening process avoids the rate-limiting step of chemical syn...

The "common" 4977 bp deletion in mitochondrial DNA (Delta4977) is commonly used as an indicator of tissue deterioration in ageing and bioenergetic diseases. Deletion levels are normally measured by a serial dilution polymerase chain reaction (PCR) approach, where test reactions are compared with dilutions of control amplifications of DNA from a similar sized stable region of the mitochondrial g...

The present work describes an accurate assay of the rate-limiting enzyme in bile acid synthesis, the cholesterol 7ahydroxylase, in human liver. The assay is based on isotope dilution-mass spectrometry, and endogenous microsomal cholesterol is used as the only substrate for the enzyme. Operative liver biopsies were obtained from patients undergoing elective cholecystectomy under highly standardi...

Butyrylcholinesterase (BChE) activity assay and inhibitor phenotyping can help to identify patients at risk of prolonged paralysis following the administration of neuromuscular blocking agents. The assay plays an important role in clinical chemistry as a good diagnostic marker for intoxication with pesticides and nerve agents. Furthermore, the assay is also commonly used for in vitro characteri...

Recently developed PCR-based reverse transcriptase (RT) assays are useful in the detection of retroviruses since they are approximately a millionfold more sensitive than conventional RT assays. However, these assays are both labor- and time-intensive. The previously described product-enhanced reverse transcriptase (PERT) assay involves a two-step RT-PCR followed by detection and quantitation of...

The serial-dilution assay is a standard microbiological method for estimating the density of organisms in a solution. The commonly used interval-estimation procedures of Woodward and deMan are described and compared. A new method for the calculation of two-sided confidence intervals, which is superior to the standard procedures, is presented. The computations are illustrated for a decimal dilut...

A single dilution enzyme-linked immunosorbent assay (ELISA), utilizing a reference serum with a known, predetermined end-titre was used to compute antibody titres of serum samples against African horsesickness virus. Compared to the complement fixation test it was found to be highly reproducible and sensitive. The assay also reduced the effect of between-test variations on test results and prov...

Using multiplex bead assays to measure urine proteins has a great potential for biomarker discovery, but substances in urine (the matrix) can interfere with assay measurements. By comparing the recovery of urine spiked with known quantities of several common analytes, this study demonstrated that the urine matrix variably interfered with the accurate measurement of low abundance proteins. Dilut...

We described an assay for theophylline in serum in which the reagents for the substrate-labeled fluorescent immunoassay procedure are dry reagents in a paper matrix. This assay format is both rapid and convenient. In one such paper strip assay, the competing drug conjugate is present in the diluting buffer (dilution-into-conjugate strip assay); in another, all necessary assay reagents are conta...