Evaluation of a rapid, point-of-care test device for the diagnosis of hepatitis C infection.

BACKGROUND: Despite considerable evolution in the quality of laboratory-based testing for detection of HCV, the availability of rapid, point-of-care tests may increase diagnoses by increasing opportunities for testing outside of traditional laboratory settings. OBJECTIVES: We evaluated the performance of a new, rapid HCV test that can be used with venous blood, finger stick blood, serum, plasma, or oral fluid and compared it to FDA-approved laboratory methods. STUDY DESIGN: HCV positive subjects as well as subjects at low risk for HCV were tested with the rapid test using all 5 specimen types and results compared to FDA-approved laboratory methods. In addition, performance was assessed in commercially available seroconversion panels. RESULTS: Sensitivity and specificity of the rapid test was equivalent to laboratory EIA and performance was comparable across all 5 specimen types. CONCLUSIONS: The OraQuick HCV Rapid Antibody Test appears suitable as an aid in the diagnosis of HCV infection.

Fibronectin enhances Campylobacter fetus interaction with extracellular matrix components and INT 407 cells.

Campylobacter fetus is a recognized pathogen of cattle and sheep that can also infect humans. No adhesins specific for C. fetus have to date been identified; however, bacterial attachment is essential to establish an infecting population. Scanning electron microscopy revealed C. fetus attachment to the serosal surface of human colonic biopsy explants, a location consistent with the presence of the extracellular matrix (ECM). To determine whether the ECM mediated C. fetus adherence, 7 C. fetus strains were assessed in a solid-phase binding assay for their ability to bind to immobilized ECM components. Of the ECM components assayed, adherence to fibronectin was noted for all strains. Attachment to ECM components was neither correlated with S-layer expression nor with cell-surface hydrophobicity. Ligand immunoblots, however, identified the S-layer protein as a major site of fibronectin binding, and modified ECM binding assays revealed that soluble fibronectin significantly enhanced the attachment of S-layer-expressing C. fetus strains to other ECM components. Soluble fibronectin also increased C. fetus adherence to INT 407 cells. This adherence was inhibited when INT 407 cells were incubated with synthetic peptides containing an RGD sequence, indicating that integrin receptors were involved in fibronectin-mediated attachment. Together, this data suggests that C. fetus can bind to immobilized fibronectin and use soluble fibronectin to enhance attachment to other ECM components and intestinal epithelial cells. In vivo, fibronectin would promote bacterial adherence, thereby, contributing to the initial interaction of C. fetus with mucosal and submucosal surfaces.

Nitration and inactivation of tyrosine hydroxylase by peroxynitrite.

Tyrosine hydroxylase (TH) is modified by nitration after exposure of mice to 1-methyl-4-phenyl-1,2,3,6-tetrahydrophenylpyridine. The temporal association of tyrosine nitration with inactivation of TH activity in vitro suggests that this covalent post-translational modification is responsible for the in vivo loss of TH function (Ara, J., Przedborski, S., Naini, A. B., Jackson-Lewis, V., Trifiletti, R. R., Horwitz, J., and Ischiropoulos, H. (1998) Proc. Natl. Acad. Sci. U. S. A. 95, 7659-7663). Recent data showed that cysteine oxidation rather than tyrosine nitration is responsible for TH inactivation after peroxynitrite exposure in vitro (Kuhn, D. M., Aretha, C. W., and Geddes, T. J. (1999) J. Neurosci. 19, 10289-10294). However, re-examination of the reaction of peroxynitrite with purified TH failed to produce cysteine oxidation but resulted in a concentration-dependent increase in tyrosine nitration and inactivation. Cysteine oxidation is only observed after partial unfolding of the protein. Tyrosine residue 423 and to lesser extent tyrosine residues 428 and 432 are modified by nitration. Mutation of Tyr(423) to Phe resulted in decreased nitration as compared with wild type protein without loss of activity. Stopped-flow experiments reveal a second order rate constant of (3.8 +/- 0.9) x 10(3) m(-1) s(-1) at pH 7.4 and 25 degrees C for the reaction of peroxynitrite with TH. Collectively, the data indicate that peroxynitrite reacts with the metal center of the protein and results primarily in the nitration of tyrosine residue 423, which is responsible for the inactivation of TH.

Teaching interpersonal skills in physician assistant programmes.

Increasing awareness that the technical competence of health professionals must be complemented by a well developed set of interpersonal skills (IPS) has resulted in the rapid growth of the formal teaching of IPS in training programmes for an important group of new health professionals in the United States-physician assistants (PAs). This is a report of a national survey which was part of a study designed to determine the extent and characteristics of IPS teaching. Most PA programmes have a specific course or a section of a large course for the teaching of IPS. Psychologists, physician assistants, and psychiatrists serve as teachers for most of these programmes. The majority of programmes teach process skills (for example, listening, responding), information-gathering skills, and psychological intervention skills (for example, demonstrating empathy). Less than half the programmes report the provision of instruction in one-to-one patient education, team membership skills, sexual and family counselling and self-care for health professionals. Most of the programmes which responded to the survey use videotechnology in teaching or assessing IPS.