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Biomedical subjects

D Taylor-Robinson

Publications and source records attributed to D Taylor-Robinson.

At least 163 records · Page 9Linked to original sources
PubMed1991

Development and evaluation of the polymerase chain reaction to detect Mycoplasma genitalium.

The polymerase chain reaction (PCR) was developed to detect Mycoplasma genitalium. Oligonucleotide primers were used to amplify a 374 bp region of the attachment protein of the mycoplasma. DNA from three strains of M. genitalium tested gave a characteristic PCR product which was not seen with DNA from any other source. As little as 10(-15) g of M. genitalium DNA could be detected and it was found in the vagina of progesterone-treated BALB/c mice inoculated with M. genitalium organisms later than they could be cultured from this site, but not in mice that never became colonised vaginally.

Animals↗
PubMed1991

Detection of Chlamydia trachomatis by direct immunofluorescence improved by centrifugation of specimens.

During a study of women with laparoscopically investigated pelvic pain, genital tract specimens were examined for Chlamydia trachomatis using a direct fluorescent antibody (DFA) technique (MicroTrak, Syva) and culture. Some smears, particularly those from the upper genital tract, contained an inadequate number of cells when examined by the DFA technique and many cell monolayers were destroyed by the specimens. To obtain results for such samples, or to confirm the original DFA result, additional specimens which had been frozen at -70 degrees C or in liquid nitrogen were centrifuged at high speed and the resulting deposit examined by the DFA technique. By this means, 32 negative results were confirmed for specimens from 10 chlamydia-negative patients with pelvic inflammatory disease or with high chlamydial antibody titres, and 26 negative results were confirmed for 19 patients who were positive at other sites. In addition, three chlamydia-positive and six chlamydia-negative results were obtained for sites where the original smear for DFA testing had been inadequate (few epithelial cells) and six specimens that were negative originally were found to be positive. Thus, of 73 specimens that were either inadequate or negative by DFA testing originally, 9 (12%) were positive by DFA testing after centrifugation.

Centrifugation↗
PubMed1991

Prostatodynia and herpes simplex virus infection.

The etiology of chronic abacterial prostatitis remains obscure, although viral agents have been postulated. Herpes simplex virus was isolated from the prostatic fluid of a patient with symptoms of prostatitis and the implications are reviewed.

Adult↗
PubMed1991

The effect of a single oral dose of azithromycin on chlamydial salpingitis in mice.

Progesterone-treated C3H mice were inoculated under the ovarian bursa with a human Chlamydia trachomatis strain, serovar E, and treated variously from one week before inoculation to two weeks afterwards with a single oral dose of azithromycin. At autopsy, all 27 control mice, not given azithromycin, had histological evidence of salpingitis. Any tubal inflammation in the 139 mice which had received greater than or equal to 60 mg azithromycin/kg was always less severe than that in control mice killed on the same day. This was true also for three of the six mice given azithromycin 25 mg/kg. Salpingitis was prevented in all 38 mice given greater than or equal to 60 mg of azithromycin on the day chlamydiae were inoculated. Inflammation was found in only 35% of mice given 60-80 mg/kg of drug from two to ten days after inoculation and was less severe than in untreated control mice. This dose given later was not as effective in preventing disease. Doses of 200-240 and 100-180 mg/kg given up to a week before inoculation reduced the proportion of mice with salpingitis to 33% and 77%, respectively, while no reduction occurred with 60-80 mg/kg, although lesions were less severe than in control mice. Chlamydiae were not detected in any part of the genital tract when greater than or equal to 60 mg/kg of azithromycin were given on the day of inoculation and were rarely detected when the drug was given a week before or up to 12 days after inoculation. Re-isolation of organisms was not always associated with histological evidence of disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Detection of Chlamydia trachomatis by the polymerase chain reaction in swabs and urine from men with non-gonococcal urethritis.

A polymerase chain reaction (PCR) was developed for Chlamydia trachomatis in which a 380 base pair DNA fragment was amplified. Amplification occurred with the DNA from the 15 serovars but not with that from other Chlamydia spp or with DNA from a variety of other organisms. Chlamydial DNA (10(-16) g) could be detected and the PCR seemed to be able to detect single organisms. Urethral swabs were obtained from 37 men with acute non-gonococcal urethritis (NGU), 18 (49%) of whom were positive for C trachomatis by MicroTrak. As a result of clinical re-examinations 65 urethral swabs were available for analysis by the PCR. In comparison with MicroTrak, PCR had a sensitivity of 95%, a specificity of 94%, a positive predictive value of 86% and a negative predictive value of 98%. The PCR was apparently less sensitive (82%) in tests on urine samples. Overall, however, values of sensitivity and specificity of the PCR compared favourably with those of MicroTrak. The PCR for C trachomatis is likely to be a valuable technique for research, but problems of DNA contamination suggest that it should not be recommended for routine diagnosis.

Base Sequence↗
PubMed1991

Simplification of procedures used to test urine samples for Chlamydia trachomatis.

Two methods of simplifying the procedure for examining urine samples for Chlamydia trachomatis were investigated. When 73 urine samples from 56 men with acute non-gonococcal urethritis were examined by direct immunofluorescence (MicroTrak), centrifuging 1 ml volumes of urine at 13,000 rpm for five minutes was at least as efficient for detecting C trachomatis as centrifuging larger volumes at 3000 rpm for 30 minutes. Furthermore, examination of urine produced during a visit to a sexually transmitted disease clinic was at least as efficient as examination of early morning urine for detecting C trachomatis by MicroTrak, or by an enzyme immunoassay (IDEIA). Both modifications have practical advantages and should encourage the use of urine samples for diagnosing chlamydial infections in men.

Bacteriological Techniques↗
PubMed1991

Screening for sexually transmitted disease in London-based male prostitutes.

OBJECTIVE: To provide a screening service for sexually transmissible infections to male prostitutes working in the London area. DESIGN: An open access service recruiting by a diverse range of methods to avoid over-representation of the more visible elements of this group. SETTING: Department of genitourinary medicine in a London teaching hospital and a community-based clinic at a safe address. RESULTS: During the 10 months following the establishment of the service in June 1990, 57 male prostitutes (38 street based and 19 "escorts") were seen. Of these, 27 men (47%) were found to have evidence of such an infection. Twenty five per cent of the street-based men had serological evidence of previous infection with hepatitis B virus (HBV), 6% had positive syphilis serology, 9% had non-gonococcal urethritis (NGU), 18% had urethral and 13% rectal gonorrhoea. None had gonorrhoea at more than one site. Twenty-seven per cent of these men were HIV 1-antibody positive. Thirty-seven per cent of the escorts had serological evidence of previous infection with HBV, none had positive syphilis serology, 11% had NGU, 5% had urethral and 8% rectal gonorrhoea. None had gonorrhoea at more than one site. Twenty-five per cent of these men were HIV 1-antibody positive. CONCLUSION: Specific targeting of resources at this group of individuals is necessary to promote better health education and use of health care provisions.

Adolescent↗
PubMed1991

The value of urine samples from men with non-gonococcal urethritis for the detection of Chlamydia trachomatis.

Chlamydia trachomatis was sought at first and subsequent clinic visits in urethral swabs and urines from 112 heterosexual men with acute non-gonococcal urethritis (NGU). In comparison with a urethral swab tested by Micro Trak (MT), a urine deposit tested in the same way was 90% as sensitive. Examining a urine deposit by the enzyme immunoassay IDEIA was a little less sensitive (89%) than examining a similar deposit by MT, and was less sensitive (82%) than examining a urethral swab by MT. The results of testing urines were little influenced by collecting them either before or after swabbing the urethra, and there was evidence that examining all of a urine sample by IDEIA would have increased sensitivity. Overall, 55 (49%) of the men were diagnosed as C trachomatis-positive based on the results of testing both a urethral swab and a urine sample. Furthermore, a small numbers of chlamydiae were detected by examining urine by MT and, to a lesser extent, by IDEIA, so that there is no reason why this non-invasive approach should not be successful in men other than those with acute NGU.

Chlamydia Infections↗
PubMed1991

Laboratory techniques for the diagnosis of chlamydial infections.

Yolk-sac inoculation of embryonated eggs was superseded 25 years ago by the use of cell cultures (often McCoy) for the isolation of Chlamydia trachomatis. Centrifugation of specimens onto the cell monolayers was shown to increase sensitivity, but little of late has further improved sensitivity which is at least ten-fold greater than that of eggs. However, culture is slow and labour intensive so that non-cultural techniques without these drawbacks have come to dominate. Direct fluorescent antibody (DFA) tests are rapid and have sensitivities that range from 70% to 100% for men and 68% to 100% for women, and specificities that range from 87% to 99% for men and 82% to 100% for women; if the tests are read by competent observers the values are at the top end of the ranges. The detection rate may be enhanced even further by relatively low-speed centrifugation of specimens before staining. Skilled reading is not a feature of enzyme immunoassays (EIAs) which according to the literature have sensitivities that range from 62% to 97% for men and 64% to 100% for women, and specificities that range from 92% to 100% for men and 89% to 100% for women. However, comparison against poor reference tests is responsible for most of the higher values and the clinician should not be misled into believing that EIAs have excellent sensitivity; the lower values in the ranges are closer to reality. Furthermore, EIAs that are being designed for use by general practitioners should be regarded with the greatest caution since lack of sensitivity means that chlamydia-positive patients will go undetected. The polymerase chain reaction (PCR) is not bedevilled by insensitivity but it is no more sensitive than the most sensitive cell culture or DFA tests. PCR is unsuitable for routine diagnosis but has a place as a research tool. For men, examination of "first-catch" urine samples by the best of the non-cultural procedures provides an acceptable non-invasive approach to diagnosis; for women, the value of examining urine may be less, but needs to be thoroughly tested. However, there is little doubt that a Cytobrush used to obtain cervical specimens holds no practical advantage over a swab. Serological tests are reliant on the provision of paired sera for making a diagnosis; high antibody titres in single sera may be suggestive of an aetiological association in deep-seated chlamydial infections (epididymitis, arthritis, salpingitis, etc), but unequivocal interpretation is unusual, particularly in an individual case, since the distinction between a current and past infection is problematical.

Bacteriological Techniques↗
PubMed1991

Intracellular location of mycoplasmas in cultured cells demonstrated by immunocytochemistry and electron microscopy.

Mycoplasma fermentans (strain 'incognitus') was incubated with HeLa cells for up to 96 h. After 24 h, mycoplasma organisms were demonstrated intracellularly by immunocytochemistry using mule anti-M. fermentans antiserum and gold labelling on ultrathin sections of both Lowicryl K4M and Araldite-embedded HeLa cells, the latter being treated with hydrogen peroxide. The Araldite-embedded cells were fixed with glutaraldehyde and osmium tetroxide in the presence of ruthenium red to stain the mucopolysaccharide surface components of both the procaryotic and eucaryotic cells. Intracellular localization of some M. fermentans organisms was confirmed by exclusion of ruthenium red from their membranes. Various numbers of mycoplasma organisms were seen per cell and occasionally some were within vacuoles, the membranes of which were also unstained by ruthenium red. The PG18 strain of M. fermentans and a strain of M. hominis were also detected intracellularly using similar methodology and homologous mule or rabbit antisera. The occasional presence of both apparently normal and some denser degenerate mycoplasmas in the same cell may indicate gradual degradation by phagolysosomal digestion.

HeLa Cells↗
PubMed1990

Chlamydia trachomatis in the fallopian tubes of women without laparoscopic evidence of salpingitis.

23 women with lower abdominal pain and Chlamydia trachomatis in the cervix, urethra, or both sites were studied. Laparoscopy was done with sampling of the endometrium and fallopian tubes for detection of C trachomatis. 11 women had laparoscopic evidence of pelvic inflammatory disease (PID); C trachomatis was detected in the upper genital tract of 8, but not in the upper tract of 5 who had laparoscopy again after treatment. The organism was also found in the upper genital tract of 9 of the 12 women without laparoscopic evidence of PID. Most of the women with abdominal pain or tenderness had tubal or endometrial C trachomatis infection, although only half had laparoscopic evidence of salpingitis. This finding suggests that antibiotic treatment should be given as soon as chlamydial infection is detected in the cervix and that pain does not necessarily point to C trachomatis in the upper genital tract. Laparoscopy may miss important pathogens in the upper genital tract, unless the procedure is complemented with detailed microbiological investigation.

Anti-Bacterial Agents↗
PubMed1990

Use of the polymerase chain reaction to detect DNA sequences specific to pathogenic treponemes in cerebrospinal fluid.

The polymerase chain reaction was used to detect Treponema pallidum in specimens of cerebrospinal fluid (CSF), as a means of diagnosing syphilis. Segments of the TmpA and 4D genes were amplified to provide an estimated threshold sensitivity of approximately 65 organisms in 0.5 ml. A spectrum of pathogens known to cause meningitis, and several non-pathogenic treponemes were unreactive. Treponema pertenue, and only one of 30 control specimens of CSF were positive. In contrast, 10 of 19 CSFs from patients being evaluated for latent or tertiary syphilis were positive, as were 7 of 28 specimens from HIV-positive patients.

Animals↗
PubMed1990

Production of prostaglandin E2 by human amnion in vitro in response to addition of media conditioned by microorganisms associated with chorioamnionitis and preterm labor.

To examine the potential role of bacterial infection in the cause of spontaneous preterm labor, human amnion cells in tissue culture were exposed to medium conditioned by culturing each of 21 microorganisms previously found in association with chorioamnionitis and preterm labor. At a final concentration of 0.1% bacterial conditioned medium, a significant stimulation of prostaglandin E2 production from amnion cells was observed for this range of microorganisms. Conditioned medium obtained from culturing Bacteroides fragilis caused a dose-related increase in prostaglandin production, final concentrations of 0.02% to 0.1% being stimulatory but greater concentrations (0.1% to 10%) causing a progressive inhibition of prostaglandin synthesis. A similar concentration-related response in which stimulation was followed by inhibition occurred on addition of increasing concentrations of phospholipase A2 to amnion cells. These data suggest that bacterial phospholipase may release arachidonic acid from amnion leading to prostaglandin E2 synthesis, but excessive addition of phospholipase and consequent increased arachidonic acid availability may give rise to substrate inhibition of cyclooxygenase enzyme and inhibit prostaglandin E2 synthesis. Overall it appears that a wide variety of microorganisms associated with preterm labor may secrete phospholipase, which liberates amnion arachidonic acid for conversion to the oxytocic agent prostaglandin E2.

Amnion↗