BackgroundIn March 2004, the OraQuick® rapid HIV antibody test became the first rapid HIV test approved by the US Food and Drug Administration for use on oral fluid specimens. Test results are available in 20 minutes, and the oral fluid test is non-invasive. From August 2004–June 2005, we investigated a sudden increase in false-positive results occurring in a performance study of OraQuick® oral-fluid rapid HIV tests in Minnesota.Methodology/Principal FindingsIn a field investigation, we reviewed performance study data on oral-fluid and whole-blood OraQuick® rapid HIV test device lots and expiration dates and assessed test performance and interpretation with oral-fluid and whole-blood specimens by operators who reported false-positive results. We used multivariate logistic regression to evaluate client demographic and risk characteristics associated with false-positive results. Next, we conducted an incidence study of false-positive OraQuick rapid HIV tests in nine US cities and tested both oral-fluid and finger-stick whole-blood specimens from clients; reactive tests were confirmed with Western blot. Sixteen (4.1%) false-positive oral-fluid results occurred in the performance study from April 15, 2004 through August 31, 2004 with unexpired devices from six test lots among 388 HIV-uninfected clients (specificity, 95.9%; 95% CI: 93.4–97.6). Three test operators who had reported false-positive results performed and interpreted the test according to package-insert instructions. In multivariate analysis, only older age was significantly associated with false-positive results (adjusted odds ratio = 4.5, 95% CI: 1.2–25.7). In the incidence study, all valid oral-fluid and whole-blood results from 2,268 clients were concordant and no false-positive results occurred (100% specificity).Conclusions/SignificanceThe field investigation did not identify a cause for the increase in false-positive oral-fluid results, and the incidence study detected no false-positive results. The findings suggest this was an isolated cluster; the test's overall performance was as specified by the manufacturer.
Prostacyclin ( PG12), the recently discovered naturally occurring product of arachidonic acid (AA) metabolism when injected into the dog causes a reduction in both heart rate and blood pressure (1). Since other prostaglandins (PG) have been shown to stimulate cardiovascular afferent neurons in the lung and heart (2) and since reflex reductions in heart rate occur following the injection of veratrum alkaloids (3), bradykinin (4), and episodes of myocardial ischemia (5), we speculated that the bradycardia induced by PGI2 might also be reflex in origin. The current study describes the cardiovascular effects of PG12 and provides evidence that the PGI2induced bradycardia is a reflex that originates with the stimulation of cardiopulmonary receptors and is mediated by vagal nerve fibers.Methods. Preparation of animals. Thirtythree male mongrel dogs (17-35 kg) were anesthetized with a mixture of equal amounts of Dial-urethane (Ciba-Geigy) and Nembutal (Abbott). Either the thorax was opened in the fourth left intercostal space for the placement of electromagnetic flow probes (Carolina Medical) and pressure cannulas in openchest dogs as previously reported (6) or catheters and a catheter-tippped flow probe were advanced into the left ventricle and aorta for the measurement of left ventricular pressure and cardiac output, and into the pulmonary artery for pressure recording and the injection of drugs in closed-chest animals. Systemic blood pressure was measured from a cannula in the brachial artery, and heart rate was calculated from the pressure pulse interval electronically (Narco). Maximum dP/dt was derived from the ventricular pressure recording and used as an indication of cardiac contractility. All data were recorded on a direct-writing oscillograph (Physiograph 6B, Narco). The animals were intubated and artificially respirated (Harvard Instruments Co.), warmed with a water-circulating heat-96 0037-9727/79/090096-05$0 I .OO/O
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.