OBJECTIVE-To assess the concordance of self-obtained vaginal swabs (SVS), first void urine samples (FVU) and provider-collected endocervical swabs (PES) for the detection of chlamydia trachomatis (CT) and neisseria gonorrrhoeae (NG) in adolescents.METHODS-A total of 342 adolescent women and 1,080 baseline and semi-annual visits were analyzed. FVU, SVS and PES were collected at each biannual visit. All specimens were tested by BDProbeTec ET ™ Amplified DNA Assay. Sensitivity, specificity, positive predictive value (PPV) negative predictive value (NPV) and Kappa Coefficient were calculated to evaluate the ability to identify possible infected cases using samples from three anatomic sites and the test agreement between any two of these three specimen types. Positive result from at least two of the three specimens collected from same subject at the same study visit was considered true positive.
RESULTS-The positivity rates for CT and NG were 26.6 and 11.7 per 100 women respectively. The sensitivities of SVS, FVU and PES for detecting CT were 97.3%, 89.2% and 90.1% respectively. For the detection of NG, the sensitivities of the three sampling methods were 100%, 88.6% and 95.5% respectively. The specificities were between 94.7% and 99.7% for both CT and NG. Kappa coefficients of CT test results were 0.89, 0.88 and 0.83 for specimen pairs SVS*PES, SVS*FVU and PES*FVU respectively. For the detection of NG, kappa coefficients were 0.91, 0.87 and 0.91 for those three pairs (all P<0.0001). Kappa > 0.75 is considered excellent agreement between specimens.CONCLUSION-There were strong agreements among SVS, PES and FVU specimens on the detection of CT and NG infections in adolescent females using nucleic acid amplification test. SVS represented as high as or more sensitive an approach for detecting both CT and NG compared to PES. Although FVU was the least sensitive sampling method, it is also the least invasive method. Thus SVS and FVU may provide a reliable alternative to endocervical specimens for CT and NG screening.
Calcium has been suggested as the second messenger link between skeletal muscle activity and AChR gene expression and synthesis. We have compared the concentrations of the Ca2+ channel antagonists D600 and nisoldipine needed both to block Ca2+ uptake into cultured myotubes and to increase AChR expression. The good correspondence between these two measurements and the use of the highly specific Ca2+ channel antagonist nisoldipine strengthens the hypothesis that AChR expression is regulated by levels of intracellular Ca2+.
Muscle fatigue may be due to a failure in excitation‐contraction coupling or an increase of ATP by products and NO. E‐c coupling alterations occur earlier and metabolic alterations take place later. We investigated these possibilities in frog skeletal muscle by continuous high frequency stimulation and different periods of repetitively stimulations. We judged the extent of e‐c or metabolic possibilities by releasing Ca2+ with 5 mM caffeine prior and immediately after fatigue.Continuously 60 Hz electric stimulations produced a force dropped to 0.33 ± 0.05 SD the control tetanus force, within a few seconds. The ratio of caffeine force development after and before fatigue was 1.02 ± 0.24 SD. This indicated that the interaction of myosin with actin was not impaired. After repetitive stimulation, the force dropped to 0.85 ± 0.04 SD (6 tetani) and 0.65± 0.11 SD (24 tetani) the control tetanus. Here, the ratio of caffeine force after and before fatigue development was 0.75 ± 0.3 SD. The concentration of caffeine used was the same as before therefore the acto‐myosin interaction was impaired during prolonged repetitive stimulations. The two types of fatigue take place.
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