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Biomedical subjects

R J Wilks

Publications and source records attributed to R J Wilks.

14 recordsLinked to original sources
PubMed1994

Viral-specific humoral immune responses following transfusion-related transmission of human T cell lymphotropic virus type-I infection.

The immunoglobulin (Ig) isotypes of antibodies to specific proteins of the human T cell lymphotropic virus type I (HTLV-I) were determined by Western blot analysis of serial specimens from six individuals who experienced HTLV-I seroconversion following blood transfusion; five remained asymptomatic carriers, while one developed HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) 32 weeks posttransfusion. Analysis of Ig isotypes demonstrated that while IgM was the most frequent early response to gag (p19, p24) and env (r21e) proteins within the first 3 months following transfusion, IgG and IgA responses could also be detected within this period. HTLV-I-specific antibody responses plateaued in all Ig isotypes, including IgM, within the next 4- to 6-month period following transfusion and persisted through the entire study period (> 4 years). Comparison of antibody profiles in Ig isotypes and IgG1 and IgG3 subclass among asymptomatic carriers and one individual who developed HAM/TSP demonstrated no evidence of isotypic prominence or IgG subclass restriction in either group. These results indicate the appearance of HTLV-I-specific IgM that persists even after the primary infection and suggest that such response does not appear to provide an early marker of seroconversion. Further, we found no evidence of isotypic prominence or restriction of the antibody response in recipients who remained asymptomatic compared to one who developed HAM/TSP.

Blotting, Western↗
PubMed1993

Sibling adult T-cell leukemia/lymphoma and clustering of human T-cell lymphotropic virus type I infection in a Jamaican family.

BACKGROUND: Human T-cell lymphotropic virus type I (HTLV-I) infection is endemic in Jamaica, with an estimated crude seroprevalence of 5%. Adult T-cell lymphoma/leukemia (ATL), a disease caused by HTLV-I, has an incidence of 1-2/100,000 in the Jamaican population. Familial ATL has not previously been reported from Jamaica. METHODS: Hospital records and histologic specimens of the two cases were reviewed. HTLV-I infection was confirmed by antibody testing and by polymerase chain reaction on paraffin-embedded tissue, where serum was unavailable. Family members were identified by the patients' parents. After giving informed consent, family members were asked to complete an interviewer-administered questionnaire and to agree to phlebotomy. RESULTS: ATL developed 10 years apart in two siblings from a Jamaican family at age 16 and 24 years. A study of 19 members of their extended family, including both parents, 2 grandparents, and 3 siblings, revealed an overall HTLV-I seroprevalence of 17%. This compared with 75% among parents and siblings living in the same household as the patients. HTLV-I antibody-positive (HTLV-I-positive) and negative family members had similar mean age. Three of 3 HTLV-I-positive subjects were breast-fed, compared with 10 of 15 HTLV-I-negative subjects. Intravenous drug abuse, sex with prostitutes, homosexuality, and blood transfusion were not reported. The mean number of sexual partners were similar. Both parents, who were antibody-positive, had polylobated atypical lymphocytes in their peripheral blood. CONCLUSION: The HTLV-I antibody seroprevalence is greater in the family than in the general population, consistent with the modes of transmission. The antibody seronegativity of both grandmothers suggests sexual transmission between parents. The development of ATL at age 16 and 24 years is consistent with maternal-infant transmission and a long latent period, as reported by other authors.

Adolescent↗
PubMed1992

A prospective study of transmission by transfusion of HTLV-I and risk factors associated with seroconversion.

To evaluate the risk of transfusion-related transmission of HTLV-I in Jamaica, a prospective study was initiated, prior to availability of a licensed HTLV-I serological screening assay. This information would prove useful in formulating strategies for blood-donor screening. We followed 118 pre-transfusion HTLV-I-negative transfusion recipients at monthly intervals post-transfusion for 1 year. Laboratory and questionnaire data were obtained at each visit to evaluate the clinical and immunological status of recipients. Cumulative incidence of HTLV-I seroconversion was estimated and risk-factor data associated with seroconversion among 66 HTLV-I-exposed transfusion recipients were analyzed. Seroconversion occurred in 24/54 (44%) of recipients of HTLV-I-positive cellular blood components, 0/12 recipients of positive non-cellular donor units and 0/52 recipients of HTLV-I-negative donor units. Significant risk factors associated with recipient seroconversion were receipt of a seropositive cellular blood component stored for less than one week [odds ratio (OR) = 6.34, 95% confidence interval (CI) = 1.83 to 21.92], male sex (OR = 4.79, 95% CI = 1.15 to 20.0) or use of immuno-suppressive therapy at time of transfusion (OR = 12.20, 95% CI = 0.95 to 156). Risk of blood-borne infection per person per year in Jamaica was estimated to be 0.009%. Our results confirm that blood transfusion carries a significant risk of HTLV-I transmission and that screening of donor blood effectively prevents HTLV-I seroconversion. Recipients at greatest risk for seroconversion were those who required multiple transfusions or who were receiving immunosuppressive therapy at the time of transfusion. These patients should be given priority in receiving selectively screened blood components, if universal blood-donor screening for HTLV-I is not possible.

Blood Donors↗
PubMed1991

Gastrointestinal parasitic infection in healthy Jamaican carriers of HTLV-I.

A subsample (1.6%; n = 13,260) of a healthy Jamaican population of food-handlers, studied by Murphy et al. (1991), who were serologically positive (n = 99) or negative (n = 113) for HTLV-I was investigated for intestinal parasitic infection using coprological methods. Helminth infection included Ascaris lumbricoides (2.8%), Trichuris trichiura (7.1%) and hookworms (6.1%). Entamoeba coli was found in 21.8% of samples, while E. hartmanni, Giardia lamblia, Endolimax nana, Iodamoeba bütschlii and Chilomastix mesnili each occurred in less than 10% of responders. T. trichiura displayed a higher prevalence (10.6 vs 3%) (chi 2 = 4.623; P = 0.03) in the HTLV-I negative group. G. lamblia was detected more frequently among HTLV-I carriers compared to controls (9.1 and 3.5%, respectively), but the association was not statistically significant (chi 2 = 2.825; P = 0.09). Infection with intestinal parasites is likely to occur independent of HTLV-I status: however, possible HTLV-I-induced immunosuppression may lead to higher intensity infections of certain organisms thus facilitating easier detection using parasitological methods. The immunomodulatory potential of HTLV-I infection in the aetiology of non-malignant diseases requires further investigation.

Analysis of Variance↗
PubMed1977

A simple model of 60Co beams for computerized radiotherapy planning.

A mathematical model of the dose in tissue from a beam of 60Co gamma rays is presented which is based on a novel fitting formula for the lateral profiles, and the properties of decrement lines. Four parameters completely specify an open field, and six parameters a wedged field to a good precision, as measured by the isodose RMS error of fit. A consequence of the method is that only one lateral profile at a depth of 10 cm needs to be measured, for open and wedged fields, in order to describe the whole field. The model is suitable either for computers or programmable calculators.

Cobalt Radioisotopes↗