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Biomedical subjects

R Gilson

Publications and source records attributed to R Gilson.

10 recordsLinked to original sources

Polymorph count for predicting non-gonococcal urethral infection: a model using Chlamydia trachomatis diagnosed by ligase chain reaction.

BACKGROUND/OBJECTIVES: The criteria for the diagnosis of non-gonococcal urethritis (NGU) on a Gram stained urethral smear are derived from previous studies which used culture as a diagnostic test for Chlamydia trachomatis. Our objectives were (1). to re-assess the relation between urethral polymorph count and C trachomatis infection, using ligase chain reaction (LCR) as the diagnostic test; and (2). to assess other possible predictors of C trachomatis infection such as symptoms, signs, demographic and behavioural variables. METHODS: We collected data from 363 men consecutively attending a genitourinary medicine clinic (excluding those with gonorrhoea and follow up visits) who had a urethral smear and a urethral LCR test for C trachomatis. The sensitivity and specificity of a discrete cut off in urethral polymorphonuclear leucocyte (PMNL) count as a diagnostic test for chlamydia urethritis were calculated. The associations between other variables, such as age and symptoms, and this infection were also estimated. RESULTS: 8% of men had C trachomatis infection and 26% of men had a PMNL count of 5 or more. Of those men with chlamydia 37% did not have NGU; 20% of men with NGU had chlamydia. Adjusted odds ratios for risk of chlamydial infection were significant for age less than 30 relative to 40 years and over (adj OR 13.6; 95% confidence interval 1.69 to 110), a PMNL count of 20 or more (6.56; 2.15 to 20.0), a PMNL count of 5-19 (3.59; 1.41 to 9.15), and the symptom of dysuria (3.27; 1.32 to 8.08). However a PMNL count of 5 or more was only 63% sensitive and 77% specific for C trachomatis infection. No association between sexual behaviour and chlamydial infection was found in this setting. CONCLUSIONS: The PMNL count is associated with presence of chlamydial infection but a large proportion of men with chlamydia have PMNL counts below the recommended cut off for a diagnosis of NSU. Lower age and the presence of symptoms may be as predictive as the urethral polymorph count for chlamydial urethritis and possibly for other urethral infections.

Adolescent↗

An outbreak of hepatitis A among young men associated with having sex in public venues.

An increase in hepatitis A virus (HAV) infection was noted among young men in the former Thames regions during 1997. A retrospective case-control study, using a standardised questionnaire at interview, was conducted in the area most affected (London and East Sussex) to investigate the hypothesis that this increase was mainly among homosexual men and to establish the risk factors associated with transmission. Forty-eight cases and 161 controls completed questionnaires. Forty-one cases (85%) described their sexuality as homosexual (p < 0.0001). Cases were more likely than controls to have eaten shellfish (Odds Ratio (OR) 2.4; 95% Confidence Interval (CI) 1.16, 5.04) during the two months before onset of illness. Cases had more sexual partners (p = 0.015), and more casual sexual partners (p = 0.007) than controls. Cases were more likely to have had sex in a gay sauna (OR 3.5; 95% CI 1.53, 8.30), or in a gay club, pub or disco (OR 2.9; 95 CI 1.29, 6.63) than controls. After adjusting for confounding factors, cases were more likely to have eaten shellfish (adjusted [adj] OR 3.0; 95% CI 1.33, 6.59) and to have had sex in a gay sauna (adj OR 3.9; 95% CI 1.42, 10.59). Public health messages need to inform homosexual men about recognised risk factors such as eating shellfish and travel abroad to endemic areas, as well as sexual risks. Homosexual men can benefit from hepatitis A vaccine. We would suggest that in an outbreak situation men who have multiple anonymous partners and have sex in public venues should be targeted as a priority for health education and immunisation.

Adolescent↗

The role of virus-specific CD8(+) cells in liver damage and viral control during persistent hepatitis B virus infection.

Hepatitis B virus (HBV) is a noncytopathic virus, and the recognition of infected hepatocytes by HBV-specific CD8 cells has been assumed to be the central mechanism causing both liver damage and virus control. To understand the role of cytotoxic T cells in the pathogenesis of HBV infection, we used functional assays that require T cell expansion in vitro and human histocompatibility leukocyte antigen (HLA)-peptide tetramers that allow direct ex vivo quantification of circulating and liver-infiltrating HBV-specific CD8 cells. Two groups of patients with persistent HBV infection were studied: one without liver inflammation and HBV replication, the other with liver inflammation and a high level of HBV replication. Contrary to expectation, a high frequency of intrahepatic HBV-specific CD8 cells was found in the absence of hepatic immunopathology. In contrast, virus-specific T cells were more diluted among liver infiltrates in viremic patients, but their absolute number was similar because of the massive cellular infiltration. Furthermore, inhibition of HBV replication was associated with the presence of a circulating reservoir of CD8(+) cells able to expand after specific virus recognition that was not detectable in highly viremic patients with liver inflammation. These results show that in the presence of an effective HBV-specific CD8 response, inhibition of virus replication can be independent of liver damage. When the HBV-specific CD8 response is unable to control virus replication, it may contribute to liver pathology not only directly but by causing the recruitment of nonvirus-specific T cells.

CD8-Positive T-Lymphocytes↗

Nevoid basal cell carcinoma syndrome and non-Hodgkin's lymphoma.

Nevoid basal cell carcinoma syndrome (NBCCS) is a hereditary disorder with a predilection for numerous basal cell carcinomas in addition to odontogenic keratocysts, palmoplantar pitting, and skeletal malformations. NBCCS has been associated with a number of benign and malignant neoplasms. We report the first case of NBCCS in association with non-Hodgkin's lymphoma.

Basal Cell Nevus Syndrome↗

Candidate gene markers associated with somatotropic axis and milk selection.

One of the obstacles to progress in dairy cattle selection is that milk production traits are only expressed after the first calving. However, the use of the quantitative trait loci (QTL) technology will improve the efficiency of dairy industry with a positive image for the consumers. QTL are part of the genome showing a preponderant action and explaining the major part of variation of the trait production. At the present time, the two major strategies developed to detect such QTL are the candidate gene approach and the positional genetics approach. The somatotropic axis contains the most promising candidates in this respect, as it strongly regulates milk production. Then, the identification of favorable QTL associated with the somatotropic axis that are significantly correlated with genetic merits for milk production could lead to more effective selection programs.

Animals↗