Biomedical subjects

V Pope

Publications and source records attributed to V Pope.

At least 19 recordsLinked to original sources

PubMed2006

Excellence in sexually transmitted infection (STI) diagnostics: recognition of past successes and strategies for the future.

Diagnostic advances do not generally receive the recognition given to prevention and treatment contributions, for the control and management of infectious diseases including sexually transmitted infections (STIs). In order to identify seminal diagnostic contributions over a half century (1950-2000), the Editorial Board of the WHO Sexually Transmitted Diseases Diagnostics Initiative (SDI) Publication Review or "electronic journal club" were asked to nominate their choices of peer-reviewed publications for special recognition. From 43 nominations, 13 were voted by a panel of 25 "experts" as having made the most significant contributions. The 1964 article by Thayer and Martin, which identified a selective media for gonococcal culture, was chosen unanimously by all panel members and is identified as the classic STI diagnostic article for this era.

Forecasting↗

PubMed2006

A multi-centre evaluation of nine rapid, point-of-care syphilis tests using archived sera.

OBJECTIVES: To evaluate nine rapid syphilis tests at eight geographically diverse laboratory sites for their performance and operational characteristics. METHODS: Tests were compared "head to head" using locally assembled panels of 100 archived (50 positive and 50 negative) sera at each site using as reference standards the Treponema pallidum haemagglutination or the T pallidum particle agglutination test. In addition inter-site variation, result stability, test reproducibility and test operational characteristics were assessed. RESULTS: All nine tests gave good performance relative to the reference standard with sensitivities ranging from 84.5-97.7% and specificities from 84.5-98%. Result stability was variable if result reading was delayed past the recommended period. All the tests were found to be easy to use, especially the lateral flow tests. CONCLUSIONS: All the tests evaluated have acceptable performance characteristics and could make an impact on the control of syphilis. Tests that can use whole blood and do not require refrigeration were selected for further evaluation in field settings.

Humans↗

PubMed2003

Maternal and congenital syphilis in Bolivia, 1996: prevalence and risk factors.

OBJECTIVES: The present study was carried out in seven maternity hospitals to determine the prevalence of maternal syphilis at the time of delivery and the associated risk factors, to conduct a pilot project of rapid syphilis testing in hospital laboratories, to assure the quality of syphilis testing, and to determine the rate of congenital syphilis in infants born to women with syphilis at the time of delivery--all of which would provide baseline data for a national prevention programme in Bolivia. METHODS: All women delivering either live-born or stillborn infants in the seven participating hospitals in and around La Paz, El Alto, and Cochabamba between June and November 1996 were eligible for enrolment in the study. FINDINGS: A total of 61 out of 1428 mothers (4.3%) of live-born infants and 11 out of 43 mothers (26%) of stillborn infants were found to have syphilis at delivery. Multivariate analysis showed that women with live-born infants who had less than secondary-level education, who did not watch television during the week before delivery (this was used as an indicator of socioeconomic status), who had a previous history of syphilis, or who had more than one partner during the pregnancy were at increased risk of syphilis. While 76% of the study population had received prenatal care, only 17% had syphilis testing carried out during the pregnancy; 91% of serum samples that were reactive to rapid plasma reagin (RPR) tests were also reactive to fluorescent treponemal antibody-absorption (FTA-ABS) testing. There was 96% agreement between the results from local hospital laboratories and national reference laboratories in their testing of RPR reactivity of serum samples. Congenital syphilis infection was confirmed by laboratory tests in 15% of 66 infants born to women with positive RPR and FTA-ABS testing. CONCLUSION: These results indicate that a congenital syphilis prevention programme in Bolivia could substantially reduce adverse infant outcomes due to this disease.

Analysis of Variance↗

PubMed2002

Objective comparison of stapled anopexy and open hemorrhoidectomy: a randomized, controlled trial.

PURPOSE: This trial compares stapled anopexy with open hemorrhoidectomy in patients with prolapsing (Grade 3) hemorrhoids. Particular attention was paid to changes in anorectal physiology, nature of tissue resected, quality-of-life assessments, and cost implications of the treatments studied. METHODS: An initial pilot study was followed by a randomized, controlled trial in a District General Hospital in the United Kingdom. All patients had Grade 3 hemorrhoids. Nineteen patients were studied in the pilot study, with 99 patients in the randomized, controlled trial. All patients in the pilot study and 59 in the randomized, controlled trial underwent stapled anopexy. Thirty patients in the randomized, controlled trial underwent open hemorrhoidectomy. Of the 59 patients in the stapled group, 32 were treated with the Ethicon PPH stapling device, and 27 received stapling with a reusable Autosuture stapling device. The following variables were measured: demographic details, quality of life (Medical Outcomes Study Short Form 36 and directed questions), anorectal manometry, and histology. RESULTS: There was no difference in the case mix within or between the groups. The stapled anopexy groups showed a significant reduction in operative time (P < 0.001) and blood loss (P < 0.001) compared with open hemorrhoidectomy. Open hemorrhoidectomy resulted in significantly greater usage of protective pads postoperatively (P < 0.001) and longer rehabilitation (P < 0.006). CONCLUSIONS: Stapled anopexy is an effective alternative treatment for prolapsing hemorrhoids that allows reduced operative time and shorter rehabilitation. It does not appear to affect continence or overall quality of life.

Adult↗

PubMed2001

Syphilis fast latex agglutination test, a rapid confirmatory test.

Using 255 serum samples with various reactivities, we evaluated the Syphilis Fast latex agglutination test (Syphilis Fast) against the Treponema pallidum particle agglutination test (TP-PA) for confirming a diagnosis of syphilis. We found 98.8% agreement between the Syphilis Fast and the TP-PA. The Syphilis Fast, however, had a couple of advantages over the TP-PA: the test takes only 8 min to perform and produces results that are easy to read. It appears to be a good confirmatory test for syphilis, especially for point-of-care clinics such as prenatal or sexually transmitted disease clinics.

Agglutination Tests↗

PubMed2000

Sexual behaviour, STDs and risks for prostate cancer.

A population-based case-control study was carried out among 981 men (479 black, 502 white) with pathologically confirmed prostate cancer and 1315 controls (594 black, 721 white). In-person interviews elicited information on sexual behaviour and other potential risk factors for prostate cancer. Blood was drawn for serologic studies in a subset of the cases (n = 276) and controls (n = 295). Prostate cancer risk was increased among men who reported a history of gonorrhoea or syphilis (odds ratio (OR) = 1.6; 95% confidence internal (CI) 1.2-2.1) or showed serological evidence of syphilis (MHA-TP) (OR = 1.8; 95% CI 1.0-3.5). Patterns of risk for gonorrhoea and syphilis were similar for blacks (OR = 1.7; 95% CI 1.2-2.2) and whites (OR = 1.6; 95% CI 0.8-3.2). Risks increased with increasing occurrences of gonorrhoea, rising to OR = 3.3 (95% CI 1.4-7.8) among subjects with three or more events (Ptrend = 0.0005). Frequent sexual encounters with prostitutes and failure to use condoms were also associated with increased risk. Syphilis, gonorrhoea, sex with prostitutes and unprotected sexual intercourse may be indicators of contact with a sexually transmissible factor that increases the risk of prostate cancer.

Adult↗

PubMed2000

Lipid removal from human serum samples.

The efficacy of lipid removal from human serum samples obtained by using Cleanascite HC, a commercially available product, was compared to that obtained by the standard chloroform method. Separate samples of 21 frozen, banked human serum samples used in the preparation of samples for proficiency testing were treated with either Cleanascite HC or chloroform. The lipid content was measured before and after treatment. The total percentages of lipid removed ranged from 61 to 70% with Cleanascite HC and from 60 to 62% with chloroform. The advantage of Cleanascite HC over chloroform is based on the simplicity of the procedure with Cleanascite HC without the environmental concerns inherent in the use of chloroform. In 15 serum samples known to contain antibodies to treponemal and nontreponemal syphilis antigens, Cleanascite HC bound some immunoglobulin, but with only minimal loss of reactivity in the serologic tests for syphilis. Cleanascite HC is therefore an acceptable alternative to chloroform for lipid reduction in human serum samples.

Chloroform↗

PubMed2000

Use of synthetic cardiolipin and lecithin in the antigen used by the venereal disease research laboratory test for serodiagnosis of syphilis.

The Venereal Disease Research Laboratory (VDRL) test is a microflocculation test for syphilis that uses an antigen containing cardiolipin, lecithin, and cholesterol. For more than 50 years, the preparation of natural cardiolipin and lecithin for this test has been based on the Pangborn method which involves isolating and purifying these components from beef hearts. This process is tedious and time-consuming and results in a variable purity range. In our studies, we found that a VDRL antigen using synthetic tetramyristoyl cardiolipin and synthetic 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (lecithin) was as specific in detecting syphilis as a VDRL antigen made with natural components. In 85% of the cases, we obtained an endpoint titer of 1/2 or 1 dilution more than a titer obtained with a VDRL antigen made with natural components. The use of these pure synthetic compounds, with a purity of 99%, would offer advantages in the standardization and stability of the VDRL antigen. Because this antigen is the basic ingredient in the preparation of nontreponemal reagents such as the rapid plasma reagin, toluidine red unheated serum test, and the unheated serum reagin, the use of this synthetic VDRL antigen should also increase the reactivity of these reagents.

Cardiolipins↗

PubMed2000

Comparison of the Serodia Treponema pallidum particle agglutination, Captia Syphilis-G, and SpiroTek Reagin II tests with standard test techniques for diagnosis of syphilis.

We compared the microhemagglutination assay for Treponema pallidum (MHA-TP), a treponemal test, with two other treponemal tests, the Serodia Treponema pallidum particle agglutination (TP-PA) assay and the Captia Syphilis-G enzyme immunoassay, using 390 clinical serum samples. We also compared two nontreponemal tests, the rapid plasma Reagin (RPR) card test and the SpiroTek Reagin II test. Agreements of the MHA-TP with the TP-PA test and the Syphilis-G test were 97.4 and 97.7%, respectively. There was 89.2% agreement between the RPR and Reagin II tests. The Reagin II test was more apt to be reactive if the treponemal test was also reactive. We conclude that either the Serodia TP-PA test or the Captia Syphilis-G test is an appropriate substitute for the MHA-TP and that the Spirotek Reagin II test could substitute for the RPR test as a screening test.

Antibodies, Bacterial↗

PubMed1999

Replacement for 30-milliliter flat-bottomed, glass-stoppered, round bottles used in VDRL antigen preparation.

When the flat-bottomed, glass-stoppered, round bottle traditionally used to make VDRL antigen was discontinued, an appropriate substitute was needed. Although many laboratories have switched to one of the other nontreponemal tests for syphilis serology screening, the VDRL test remains the only approved procedure for testing spinal fluids of patients with possible neurosyphilis. We tested 25-ml glass-stoppered, convex-bottomed Erlenmeyer flasks to determine if these could be used as appropriate substitutes. We tested 52 reactive sera and 54 nonreactive sera by using one reference antigen prepared in the traditional flat-bottomed bottles and five antigens prepared in the Erlenmeyer flasks. Results with all serum samples were comparable. We also tested two lots of a commercial antigen plus an additional lot of reference antigen. Again there was no difference in the reactivity of the antigens. Therefore, we conclude that 25-ml glass-stoppered Erlenmeyer flasks can be used as an appropriate substitute for glass-stoppered, flat-bottomed, round glass bottles in the making of VDRL antigen.

Cardiolipins↗

PubMed1999

The use of Western blotting as the confirmatory test for syphilis in patients with rheumatic disease.

OBJECTIVE: As a direct or indirect result of antiphospholipid antibody production, subjective laboratory interpretation, and false positive results, the common serologic tests for syphilis have been inherently inaccurate diagnostic tests in patients with systemic lupus erythematosus (SLE) and other autoimmune diseases. We assessed the diagnostic accuracy of syphilis testing in patients with SLE and other autoimmune diseases using the treponemal Western blot (TWB) as the gold standard. METHODS: A prospective cohort study carried out at a tertiary care medical center. We studied 107 patients with autoimmune disease, 50 with at least one positive serologic test for syphilis and 57 disease matched controls. Prior to enrollment all eligible patients underwent a clinical assessment performed by at least 2 rheumatologists to confirm a diagnosis of rheumatic disease. All subjects underwent serologic testing, in blinded fashion, for syphilis using the rapid plasma reagin test (RPR), Venereal Disease Research Laboratory test (VDRL), fluorescent treponemal antibody absorption test (FTA-ABS), and the TWB. RESULTS: Eighty-seven percent of the patients studied were female, the mean age was 46.5 years, and the most common diagnosis at the time of enrollment was SLE. Using the TWB as the gold standard diagnostic test for syphilis, the sensitivity, specificity, and positive predictive values for each syphilis test were calculated. The sensitivity and specificity for the RPR in patients with rheumatic disease was 62.5% (95% confidence interval 24.5 to 91.5%) and 91.9% (95% CI 84.2 to 96.2%), respectively. The sensitivity and specificity for the VDRL were 37.5% (95% CI 8.5 to 75.5%) and 89.9% (95% CI 81.8 to 94.8%), respectively. Confirmatory syphilis testing using the FTA-ABS showed a sensitivity of 100% (95% CI 68.6 to 100%) and a specificity of 67.7% (95% CI 57.4 to 76.5%). Eight patients tested positive for syphilis by Western blotting. For the FTA-ABS test, there was a significantly higher number of false positive results (n = 32) compared to false negative results (n = 0), p < 0.0005. CONCLUSION: The FTA-ABS is not an accurate confirmatory test for syphilis in patients with SLE and other autoimmune diseases. While a negative FTA-ABS may exclude syphilis infection in the majority of cases, a positive FTA-ABS test result cannot assuredly confirm syphilis infection in this population. Western blotting is an accurate confirmatory test for syphilis and may be necessary to unequivocally discern the immunological response of syphilis from that of an underlying autoimmune disease.

Blotting, Western↗

PubMed1999

Congenital syphilis in a newborn: an immunopathologic study.

A 3-week-old girl presented to the emergency room with respiratory distress and generalized maculopapular rash. The newborn was hospitalized with a presumptive diagnosis of congenital syphilis, but she died after 2 days of therapy. Tissue from the gastrointestinal tract, brain, liver, spleen, and lung was studied by using direct fluorescent antibody and immunohistochemical analysis (IHC) for Treponema pallidum. The inflammatory infiltrate was characterized by using IHC against CD3, CD20, CD68, and smooth muscle actin. The diagnosis of congenital syphilis was confirmed by demonstrating spirochetes in tissues with IHC and direct fluorescent antibody examination. IHC showed abundant treponemes in the small intestine and liver and occasional spirochetes in the meninges. Bacteria were seen as intact spirochetes, granular staining, or large extracellular collections of antigen. A constant pathologic feature throughout the tissues was concentric macrophage (CD68-positive) infiltrate around vessels, giving an onion-skin appearance. IHC identified the macrophages as the prime immune response in congenital syphilis.

Antigens, CD↗

PubMed1998

Increase in endocervical CD4 lymphocytes among women with nonulcerative sexually transmitted diseases.

To assess associations of nonulcerative sexually transmitted diseases (STDs) with human immunodeficiency virus (HIV)-susceptible leukocytes on female genital mucosa, cervicovaginal specimens from 32 HIV-negative STD clinic patients with gonorrhea, chlamydial infection, or trichomoniasis were compared with specimens from 32 clinic patients without these infections. Twenty-eight patients had single infections (15 gonorrhea, 10 chlamydial infection, 3 trichomoniasis), and 4 had dual infections. A saline vaginal wash and saline suspensions of vaginal wall scrapings, ectocervical scrapings, and endocervical brushings were analyzed by flow cytometry. Specimens from the endocervix had the highest proportions of lymphocytes, monocytes, and Langerhans' cells. The median number of endocervical CD4 lymphocytes/10,000 cells was greater among patients with STDs than among those without (476 vs. 245; P < .001). These data suggest that the endocervix may have a particularly important role in heterosexual HIV transmission and that nonulcerative STDs may facilitate HIV transmission by increasing the presence of CD4 lymphocytes at this site.

Adolescent↗

PubMed1998

Treponemal specific tests for the serodiagnosis of syphilis. Syphilis and HIV Study Group.

OBJECTIVES: To determine the rate of concordance of the Microhemagglutination Assay for Antibodies to T. pallidum (MHA-TP) and the Fluorescent Treponemal Antibody-Absorption test (FTA-ABS) prior to therapy in patients with early stage syphilis and to assess the incidence of and associated risk factors for seroreversion of these treponemal specific tests during the first year after therapy for early syphilis. DESIGN: Multicenter, prospective, cohort treatment study of patients with early syphilis. METHODS: Five hundred twenty-five patients were enrolled in a study to evaluate the response of early syphilis to either benzathine penicillin 2.4 million units intramuscularly once or this therapy plus amoxicillin 2 g and probenecid 500 mg orally both three times daily for 10 days. Serologic and clinical follow-up was conducted at intervals over 1 year. MHA-TP and FTA-ABS tests were performed on serologic specimens from each patient visit. RESULTS: Enrollment specimens showed 5% discordant MHA-TP and FTA-ABS results with 85% of these demonstrating a nonreactive MHA-TP. This occurred most commonly in primary syphilis. In patients who had a 1-year serologic follow-up with FTA-ABS or MHA-TP, seroreversion occurred in 9% and 5% of cases, respectively. No association between HIV-seropositivity and TST seroreversion was demonstrated. CONCLUSION: The MHA-TP may be less sensitive than the FTA-ABS for identifying patients with primary syphilis. Treponemal specific tests may become nonreactive during the first year after therapy for early syphilis.

Amoxicillin↗

PubMed1998

An analysis of the value of some antigen-antibody interactions used as diagnostic indicators in a treponemal Western blot (TWB) test for syphilis.

Densiometric quantitation and spreadsheet normalization were used to refine the parameters defining a treponemal Western blot (TWB) test for syphilis. Initially using 84 defined reactive and 105 defined non-reactive sera, we determined that the immune response to the 17 kDa antigen was the most critical of the following three candidate test determinants: the 47 kDa, 17 kDa and 15.5 kDa bands. In a second study using 124 cases of clinically diagnosed syphilis and 354 "normal" donors, a diluted serum sample was included as a minimal reactive control for the 17-kDa immune response. Reactivity to all three test determinants was obligatory for a test result to be interpreted as positive. Of the 124 cases of syphilis, 7 were nonreactive by TWB (sensitivity = 94%); of the 354 normal donors, 7 tested reactive (specificity = 98%). Forty (11%) normal serum samples had detectable but less than minimal reactivity to the 17 kDa band. Frequencies of immune response to a larger group of 12 antigens were tallied for the 124 clinically diagnosed cases of syphilis and an equal subset (124) of the normal group. In the normal subset, 72% and 52% of the samples had detectable reactivity to the 47 and 15.5 kDa antigens, respectively, while 10%, 5% and 3% reacted with the 17, 24 and 44.5 kDa antigens, respectively. Follow-up TWB testing of the clinically diagnosed cases revealed that previously untreated patients with primary or secondary syphilis were more likely to a show decrease in TWB reactivity than patients with latent symptoms who had been treated previously. As a diagnostic indicator of syphilis, the 17-kDa antigen was found to have the best combined attributes of sensitivity and specificity. Although, the highly specific 44.5 kDal and 24 kDal bands were often redundant as diagnostic indicators they are useful for the interpretation of borderline results. In addition, absence of the highly sensitive 47 and 15.5 kDa indicators should be useful in resolving some problem diagnoses.

Antibodies, Bacterial↗

PubMed1995

Instrument-dependent fluorochrome sensitivity in flow cytometric analyses.

Flow cytometry has become the preferred technique by which critical clinical evaluations are made such as CD4 counts and aneuploid analyses. Mounting concern has arisen over the numerous techniques, reagents, and different flow cytometric employed to determine these data. Several studies have documented significant differences in results when different flow cytometers are utilized to analyze the same sample. Fluorochrome-dependent instrument sensitivity also has been reported by numerous investigators. As more and more procedures are performed by cytometric analysis, light scatter and fluorescence limitations, which appear to be instrument dependent, demonstrate that not all flow cytometers have the same capabilities. Attempts were made to calculate molecules of equivalent soluble fluorochrome (MESF) values on nine different flow cytometers using fluorescein isothiocyanate (FITC) and R-phycoerythrin (R-PE) labeled microsphere reference standards produced by Flow Cytometry Standards Corporation (FCSC). Dramatic differences were observed in the ability of some cytometers to resolve these microspheres. The diminished resolution appeared to be instrument model and fluorochrome dependent. We propose that diminished fluorescence resolution in certain flow cytometers could be responsible for significant variability in clinical values reported from laboratories utilizing different flow cytometers.

Flow Cytometry↗

PubMed1994

Flow cytometric analysis of peripheral blood lymphocyte immunophenotypes in persons infected with Treponema pallidum.

To characterize the human immune response to syphilis, we determined the effect of infection with Treponema pallidum on the percentage of the various lymphocyte subpopulations in the peripheral blood of infected and uninfected persons. Monoclonal antibodies labeled with either fluorescein isothiocyanate or phycoerythrin were used to perform dual color analysis on a FACScan with the following markers: CD3 for total T cells, CD4 for T helper cells, CD8 for T suppressor cells, CD19 for B cells, and CD16 plus CD56 for natural killer cells. Lymphocyte immunophenotype results were analyzed by the stage of untreated syphilis and by gender. Although they were within the ranges of the normal distribution of immunophenotypes, the percentages of CD4+ cells were significantly lower (P < 0.001) and those of CD8+ cells were higher (P = 0.03) in patients with syphilis than in the uninfected population. For infected versus uninfected subjects, both women and men, the differences in the mean percentages of CD3+ and CD4+ cells were significant (P < or = 0.05). Significant differences were noted between the sexes in secondary syphilis only in the mean percentages of cells positive for CD3, CD4, CD8, and CD16 plus CD56. Gender had no effect on lymphocyte subpopulations in subjects with primary or latent syphilis. In the control population, significant differences due to gender were observed in the percentages of cells positive for CD3, CD4, and CD16 plus CD56.

B-Lymphocytes↗

PubMed1992

Specific immunofluorescent staining of pathogenic treponemes with a monoclonal antibody.

Two hybrid cell lines which produced mouse monoclonal antibody to the DAL-1 street strain of Treponema pallidum subsp. pallidum were established. These monoclonal antibodies strongly reacted with T. pallidum subsp. pallidum (Nichols strain, DAL-1, and two other street strains, strains MN-1 and MN-3) and T. pallidum subsp. pertenue by indirect microimmunofluorescent antibody and enzyme-linked immunosorbent assay techniques, but they did not react with normal rabbit testicular tissue. These monoclonal antibodies did not react with nonpathogenic treponemes, such as T. phagedenis Reiter, T. denticola MRB, T. refringens Noguchi, or other spirochetes, such as Borrelia burgdorferi and Leptospira interrogans serovar pomona in microimmunofluorescent antibody smear slides or in Western blots (immunoblots). While unlabeled antibodies are useful for investigating the antigenic structures of T. pallidum, we labeled these monoclonal antibodies with fluorescein isothiocyanate and used them for diagnosing syphilis by direct staining of lesion exudate or T. pallidum subsp. pallidum in formalin-fixed tissues from patients suspected of having syphilis. Both monoclonal antibodies were directed against antigens of T. pallidum subsp. pallidum with a molecular weight of 37,000 as determined by the Western blotting technique.

Animals↗