Evaluation of Syva's enzyme immunoassay for the detection of Chlamydia trachomatis in urogenital specimens.

A newly developed microwell enzyme immunosorbent assay (EIA) system by Syva Company (Palo Alto, CA) can detect Chlamydia trachomatis in < 3 hr. It uses a polyclonal antibody to chlamydial lipopolysaccharide and end points are determined with a spectrophotometer. Three clinical trial sites (University of California Medical Center, San Francisco, CA; University of Washington, Seattle, WA; and Louisiana State University Medical Center, New Orleans, LA), compared this EIA with tissue culture (TC) for identifying Chlamydia in urogenital specimens. Overall prevalence by TC was 10.4% (136 of 1306). When tests were compared with TC (using vials or microtiter plates and a fluorescent antibody stain), we found an EIA sensitivity of 93.4% (127 of 136) and a specificity of 98.1% (1148 of 1170). This EIA has a performance profile that is, at the very least, comparable with other nonculture methods for diagnosing genital tract infections with C. trachomatis.     

Impact of patient characteristics on performance of nucleic acid amplification tests and DNA probe for detection of Chlamydia trachomatis in women with genital infections

The performance of nucleic acid amplified tests (NAAT) for Chlamydia trachomatis at the cervix and in urine was examined in 3,551 women, and the impacts of clinical findings (age, endocervical and urethral inflammation, menses, and gonococcal coinfection) were assessed. Ligase chain reaction (LCR) and first-generation uniplex PCR were studied relative to an unamplified DNA probe (PACE2) and to an expanded, independent diagnostic reference standard. Relative to the expanded standard, cervical or urine LCR was generally the most sensitive test in most subgroups. Increased detection by NAAT of cervical C. trachomatis over PACE2 was highest among women without mucopurulent endocervical discharge versus those with (relative increase in positivity with cervical LCR, 46%) and among women > or =20 years old versus younger women (relative increase in positivity with cervical LCR, 45%). The sensitivity of cervical PCR was highest when mucopurulent endocervical discharge was present (84%) and highest for cervical LCR when cervical gonococcal coinfection was detected (91%). Urethral inflammation was associated with higher sensitivities of urine LCR (86 compared to 70% when inflammation was absent) and PCR (82 compared to 62% when inflammation was absent). Menses had no effect on test performance. The effects of patient characteristics on test specificities were less pronounced and were closely related to observed sensitivities. These findings support expanded use of NAAT for screening and diagnosis of C. trachomatis in diverse clinical populations of women.     

Is urine leukocyte esterase test a useful screening method to predict Chlamydia trachomatis infection in women?

We evaluated the use of the leukocyte esterase test (LET) on first-catch urine specimens from women as a screening test to predict infection with Chlamydia trachomatis. For diagnosis, we used Abbott's ligase chain reaction (LCR) on urine specimens and isolation by tissue culture (TC) on cervical brushes. Of 4,053 women attending sexually transmitted disease and family planning clinics, 4.3% (n = 174) were positive by TC and 5.9% (n = 239) were positive by LCR. When LET was compared to TC, the sensitivity, specificity, positive predictive value, and negative predictive value were 54.0, 67.0, 6.8, and 97.0%, respectively. The corresponding performance of LET versus LCR was 53.1, 67.3, 10.1, and 95.8%. Almost half of the laboratory-confirmed chlamydial infections were negative by LET. The low specificity probably reflects multiple causes of pyuria in women and results in a low positive predictive value. LET is neither sensitive nor specific as a predictor of chlamydial infection and cannot be recommended for use as a screening test for C. trachomatis with first-catch urine samples from females from low- or moderate-prevalence populations.     

Linking Clients from HIV Antibody Counseling and Testing to Prevention Services

The effectiveness of HIV antibody counseling and testing as a prevention intervention is limited: persons testing seronegative do not usually change their risk behaviors, some actually increase their risk behaviors, and decreases in risk behaviors are usually short-lived. Referrals to additional prevention and other needed services are therefore recommended, although the extent and determinants of referral provision for persons testing seronegative are unknown. We assessed the prevalence of referrals and the association between risk behaviors and prevention referrals among seronegatives. We reviewed HIV testing and referral data on all persons receiving confidential seronegative test results in San Francisco (SF) in the first 10 months of 1995 (n = 5,595), and gathered more detailed referral information at the municipal STD clinic from November 1995 through May 1996 (n = 747). The overall prevalence of referrals was low: a referral was given to 19.1% of the SF sample and 10.6% of the STD clinic sample; 15.4% of the SF sample and 5.9% of the STD clinic sample received a prevention referral. Injection drug users (IDUs) were the most likely to receive a prevention referral (48.5% of SF IDUs, 36.4% of STD clinic IDUs); men having sex with men and women with high-risk partners were also more likely to get a prevention referral than others. For SF IDUs, unsafe sex and needle sharing were not associated with an increased likelihood of receiving a prevention referral. Opportunities to link high-risk clients from counseling and testing to HIV prevention services are being missed. The referral component of HIV counseling and testing should be improved.     

The Effect of Thigh Muscle Reconditioning by Electrical Stimulation on Urodynamic Activity in SCI Patients

ABSTRACT

Various forms of electrical stimulation are being used more frequently for bladder and muscle rehabilitation following spinal injury. Fifteen patients with spinal cord injury underwent a four to eight week period of thigh muscle reconditioning by surface electrical stimulation. The accumulated effects of this program on bladder function were assessed by urodynamic evaluation before and after the test period. Seven patients had beneficial changes of either an increase in bladder capacity and/or a decrease in bladder pressure. Six patients had a decrease in bladder capacity and/or an increase in bladder pressure, although two of these six patients had resolution of spinal shock. Two patients with detrusor areflexia had no changes in pressure or capacity. There was no change in the basic urodynamic patterns, only the parameters of bladder capacity and pressure. Increasing the use of electrical stimulation for rehabilitation of the spinal cord population might alter bladder function, although not consistently. One should, therefore, be aware of these changes when setting up such rehabilitation programs.     

Role of plasminogen activator inhibitor-1 in promoting fibrin deposition in rabbits infused with ancrod or thrombin

The role of defective fibrinolysis caused by elevated activity of plasminogen activator inhibitor-1 (PAI-1) in promoting fibrin deposition in vivo has not been well established. The present study compared the efficacy of thrombin or ancrod, a venom-derived enzyme that clots fibrinogen, to induce fibrin formation in rabbits with elevated PAI-1 levels. One set of male New Zealand rabbits received intravenous endotoxin to increase endogenous PAI-1 activity followed by a 1-hour infusion of ancrod or thrombin; another set of normal rabbits received intravenous human recombinant PAI-1 (rPAI-1) during an infusion of ancrod or thrombin. Thirty minutes after the end of the infusion, renal fibrin deposition was assessed by histopathology. Animals receiving endotoxin, rPAI-1, ancrod, or thrombin alone did not develop renal thrombi. All endotoxin-treated rabbits developed fibrin deposition when infused with ancrod (n = 4) or thrombin (n = 6). Fibrin deposition occurred in 7 of 7 rabbits receiving both rPAI-1 and ancrod and in only 1 of 6 receiving rPAI-1 and thrombin (P < .01). In vitro, thrombin but not ancrod was inactivated by normal rabbit plasma and by purified antithrombin III or thrombomodulin. The data indicate that elevated levels of PAI-1 promote fibrin deposition in rabbits infused with ancrod but not with thrombin. In endotoxin-treated rabbits, fibrin deposition that occurs with thrombin infusion may be caused by decreased inhibition of procoagulant activity and not increased PAI-1 activity.     

Cost-effectiveness of Chlamydia Vaccination Programs for Young Women

We explored potential cost-effectiveness of a chlamydia vaccine for young women in the United States by using a compartmental heterosexual transmission model. We tracked health outcomes (acute infections and sequelae measured in quality-adjusted life-years [QALYs]) and determined incremental cost-effectiveness ratios (ICERs) over a 50-year analytic horizon. We assessed vaccination of 14-year-old girls and catch-up vaccination for 15–24-year-old women in the context of an existing chlamydia screening program and assumed 2 prevaccination prevalences of 3.2% by main analysis and 3.7% by additional analysis. Estimated ICERs of vaccinating 14-year-old girls were $35,300/QALY by main analysis and $16,200/QALY by additional analysis compared with only screening. Catch-up vaccination for 15–24-year-old women resulted in estimated ICERs of $53,200/QALY by main analysis and $26,300/QALY by additional analysis. The ICER was most sensitive to prevaccination prevalence for women, followed by cost of vaccination, duration of vaccine-conferred immunity, and vaccine efficacy. Our results suggest that a successful chlamydia vaccine could be cost-effective.     

Hormone responsive human breast cancer in long-term tissue culture: effect of insulin.

The mechanisms of steroid and peptide hormone action in human breast cancer are poorly understood. We have previously characterized a cell line of human breast cancer in long-term tissue culture that possesses various steroid hormone receptors and responses, providing a model for the study of steroid hormone action. The present studies describe a human breast cancer in vitro that responds to physiologie concentrations of insulin with an increased rate of macromolecular synthesis and growth. Thymidine and uridine incorporation in cells in serum-free medium are stimulated by 10(-11) M insulin and are maximal with 10(-8) M. Leucine incorporation is stimulated by 5 X 10(-11) M insulin and is maximal with 10(-9) M. Significant stimulation of uridine and leucine incorporation is evident by 3 hr and maximal by 10 hr. A 10-hr lag period exists for insulin stimulation of thymidine incorporation, which is maximal form 14 to 24 hr. The effect of 10(-8) M insulin on macromolecular synthesis is accompanied by a 69% increase above controls in the number of cells after 24 hr. The effect on macromolecular synthesis is observed in glucose-free medium. Insulin's effect on protein synthesis is not blocked by inhibition of RNA synthesis with actinomycin D. Glucocorticoids partially inhibit the action of insulin in these cells. This system provides a model for studying insulin action, and suggests that some human breast cancer may show growth regulation by insulin.