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Biomedical subjects

W N Gibbs

Publications and source records attributed to W N Gibbs.

At least 19 recordsLinked to original sources
PubMed2006

Pituicytoma: diagnostic features on selective carotid angiography and MR imaging.

We report a case of pituicytoma, a rare primary tumor of the neurohypophysis. A 64-year-old man presented with progressive visual complaints, bitemporal hemianopsia, and headache. Imaging studies revealed distinctive features of a mass lesion that thickened the pituitary stalk with a bilobed protrusion extending into the hypothalamus. Angiography demonstrated tumor vascular supply from the superior hypophyseal arteries representing the diencephalic branches of the internal carotid arteries. We discuss the imaging and pathology of this unusual tumor.

Astrocytoma↗
PubMed1998

Health status in the Caribbean. Has the faculty of medical sciences made a difference?

The Faculty of Medical Sciences has contributed to improvements in health status in the Caribbean through its research, training, and service and outreach programmes. Basic and applied research has yielded important scientific data and information that has guided health care, resulting in decreases in morbidity and mortality. Physicians graduating from its undergraduate programme and successfully completing its graduate programmes, and nurses and other professionals trained in the Faculty, are widely dispersed throughout the Caribbean and, together with Faculty staff members, have collaborated with others to formulate and implement health policies, and to provide the facilities for health education and promotion, and for the care of ill patients. Outreach programmes include organising and/or participating in projects, conferences, workshops or consultations for or with countries or organisations. Collaboration and partnership for all of these activities have been important. The problems and challenges are discussed, with an outline of some of the plans being employed to resolve them.

Community-Institutional Relations↗
PubMed1996

A case-control study of risk factors for seropositivity to human T-lymphotropic virus type I (HTLV-I) in Jamaica.

BACKGROUND: We investigated behavioural and environmental risk factors for seropositivity to human T-lymphotropic virus type I (HTLV-I). METHODS: A nested case-control study of 201 HTLV-I seropositive subjects and 225 age- and sex-matched seronegative controls was performed using questionnaire data from the enrollment visit of a cohort study in 1987-1988. HTLV-I serostatus was confirmed using enzyme-linked immunosorbent assay (ELISA) and Western blot. RESULTS: Among women, the number of lifetime sexual partners (P < 0.05, chi 2 trend) and the number of different men fathering a child by the woman (P < 0.06, chi 2 trend) were associated with HTLV-I seropositivity. Use by the female subject of an intrauterine device (IUD) was associated with an increased risk of seropositivity (odds ratio (OR) = 2.67, 95% confidence interval (CI): 1.13-6.23); condom use was rare in this population. Among male subjects, a larger number of lifetime sexual partners was also associated with HTLV-I seropositivity (P < 0.05, chi 2 trend). No association was found between HTLV-I seropositivity and educational attainment, income, or occupation. Having been breastfed as a child or receipt of a blood transfusion had elevated but imprecise OR due to very high and low prevalence of the risk factors, respectively. Several variables relating to insect or animal exposure showed no association with HTLV-I seropositivity. CONCLUSIONS: These data confirm that heterosexual intercourse is a major route of HTLV-I transmission, but do not support suggestions of insect or environmental vectors.

Adult↗
PubMed1996

Health effects of human T-lymphotropic virus type I (HTLV-I) in a Jamaican cohort.

BACKGROUND: Other than adult T-cell leukaemia (ATL) and HTLV-I associated myelopathy (HAM), the health effects of infection with human T-lymphotropic virus type I (HTLV-I) are not well defined. METHOD: A cohort of 201 confirmed HTLV-I seropositive Jamaican food service workers and 225 seronegative controls of similar age and sex from the same population was examined. A health questionnaire, physical examination, and laboratory tests were performed at enrollment into the cohort in 1987-1988. RESULTS: One of 201 HTLV-I seropositives, but no controls were diagnosed with HAM, for a prevalence of 0.5% (95% confidence interval) (CI) 0.01-2.7%); no cases of ATL were diagnosed. While there was no difference in current symptoms, the HTLV-I seropositive group was more likely to report a past medical history of hepatitis or jaundice (OR = 3.49, 95% CI: 0.93-13.08), malaria (OR = 2.13, 95% CI: 0.96-4.73), and dengue fever (OR = 1.37, 95% CI: 0.82-2.29); however, these differences were of borderline statistical significance. Low income HTLV-I seropositive women had lower body weight (P < 0.01) and body mass index (P < 0.009) than their seronegative counterparts; similar differences were seen in the smaller male group. A trend toward higher prevalence of severe anaemia (haemoglobin < 10 g/dl) (12.6% versus 7.7%, P < 0.105) and a significantly lower prevalence of eosinophilia (1.0% versus 6.3%, P < 0.004) was seen among HTLV-I seropositives compared to controls. CONCLUSIONS: Although most HTLV-I seropositives are asymptomatic, HAM may be diagnosed in approximately 0.5% of carriers. Chronic HTLV-I infection may also exert subtle effects on body mass and haematological parameters.

Adult↗
PubMed1994

Blood safety in developing countries.

This study, based on responses to a questionnaire, was undertaken to define problems in and formulate solutions for improving blood safety in developing countries as part of an effort to monitor the status of blood transfusion services globally. Despite improvements between 1988 and 1992, only 66% of developing countries (DGCs) and 46% of least developed countries (LDCs) screen all blood donations for antibodies to human immunodeficiency viruses; 72% DGCs and 35% LDCs test all donations for hepatitis B surface antigen and 71 and 48%, respectively, for syphilis. The antihuman globulin test is performed routinely in 62% DGCs and 23% LDCs, and inadequate quality assurance in all aspects of preparatory testing is a major weakness in many countries. The blood supply is usually insufficient: none of the LDCs and 9% of the DGCs collect 30 units or more per 1,000 of the population annually. Blood donor systems are totally voluntary and non-remunerated in 15% DGCs and 7% LDCs; 80% DGCs and 93% LDCs rely totally or partially on replacement donors and 25% of both groups on paid donations. The proportion of repeat donors is low (medians: 47% in DGCs, 20% in LDCs), and discard rates for collected blood are often high (up to 33%). Most of the blood collected is transfused as whole blood, and most DGCs and LDCs have inadequate supplies of plasma substitutes for management of acute haemorrhage. The reasons for these problems and suggested solutions are discussed.

AIDS Serodiagnosis↗
PubMed1991

Human T-lymphotropic virus type I (HTLV-I) seroprevalence in Jamaica. I. Demographic determinants.

During 1985 and 1986, the authors measured antibodies to human T-lymphotropic virus type I (HTLV-I) in a cohort of 13,260 Jamaicans from all parts of the island who applied for food-handling licenses. HTLV-I seroprevalence was strongly age and sex dependent, rising from 1.7% (10-19 years) to 9.1% (greater than or equal to 70 years) in men and from 1.9% (10-19 years) to 17.4% (greater than or equal to 70 years) in women. In a logistic regression analysis, women were more likely to be seropositive than were men, and farmers, laborers, and the unemployed were more likely to be HTLV-I seropositive than were those reporting student or professional occupations. In men, African ethnicity was associated with HTLV-I seropositivity in the univariate analysis but was not a risk factor after adjustment for age and sex. There was a trend toward higher age-stratified HTLV-I seroprevalence among younger women who reported more pregnancies, but older multigravidas had lower rates of HTLV-I seropositivity. Persons born outside Jamaica had significantly lower seroprevalence than did those born in Jamaica, but they were of slightly different ethnic and occupational compositions than those born in Jamaica.

Adolescent↗
PubMed1991

Human T-lymphotropic virus type I (HTLV-I) seroprevalence in Jamaica. II. Geographic and ecologic determinants.

An island-wide cohort of 13,260 Jamaicans who applied for food-handling licenses during 1985 and 1986 were tested for antibodies to human T-cell lymphotropic virus type I (HTLV-I). Demographic and residence history data were linked to geographic and ecologic measures of elevation, rainfall, crop-growing areas, population density, and additional measures of urbanization and correlated with HTLV-I antibody status. By logistic regression analysis (performed separately for men and women), men and women who currently resided at low elevation (less than or equal to 1,000 ft (305 m)) were more likely to be HTLV-I infected than were those residing at high elevation. Men, but not women, who were born in citrus-growing areas were more likely to be HTLV-I infected than were men who were born in other areas. By univariate analysis, there was a significant positive trend of increasing HTLV-I seroprevalence with increasing amount of annual rainfall associated with birthplace and primary residence areas. However, these associations did not remain significant after adjusting for age and sex. These environmental associations raise the possibility of new modes of viral transmission or host response to infection, although they may simply be surrogates for socioeconomic status, breastfeeding habits, or sexual behavior, which are known determinants of HTLV-I zero prevalence.

Adolescent↗
PubMed1989

Sexual transmission of human T-lymphotropic virus type I (HTLV-I).

STUDY OBJECTIVE: To study the seroprevalence of human T-lymphotropic virus type I (HTLV-I) in a sexually active population and to determine sexual behavior risk factors for infection. DESIGN: Cross-sectional seroprevalence study using enzyme-linked immunosorbent assay (ELISA) and Western blot. Risk-factor data were gathered by administered questionnaire and chart review. SETTING: Two urban, primary care clinics for persons with sexually transmitted diseases run by the Jamaican Ministry of Health. PATIENTS: Of the 2050 consecutive patients presenting with new episodes of sexually transmitted disease, 1977 patients were eligible for analysis. MEASUREMENTS AND RESULTS: Overall HTLV-I seroprevalence was 5.7%; prevalence increased with age from 1.6% (age, 14 to 19 years) to 5.1% (age, 30 years and older) in men and from 5.3% (age, 14 to 19 years) to 14.1% (age, 30 years and older) in women. Compared with a reference cohort of food service employees, age-adjusted HTLV-I seroprevalence was increased in female patients with sexually transmitted disease (odds ratio = 1.83; CI, 1.41 to 2.83) but not in male patients with sexually transmitted disease. Independent risk factors for HTLV-I infection in women included having had more than ten lifetime sexual partners (odds ratio = 3.52, CI, 1.28 to 9.69) and a current diagnosis of syphilis (odds ratio = 2.12; CI, 1.12 to 3.99). In men, a history of penile sores or ulcers (odds ratio = 2.13; CI, 1.05 to 4.33) and a current diagnosis of syphilis (odds ratio = 3.56; CI, 1.24 to 10.22) were independent risk factors for HTLV-I infection. Of 1977 patients, 5 (0.3%) had antibodies to human immunodeficiency virus type 1 (HIV-1), including 2 with HTLV-I and HIV-1 coinfection. CONCLUSIONS: We conclude that HTLV-I is transmitted from infected men to women during sexual intercourse. Our data are consistent with the lower efficiency of female-to-male sexual transmission of HTLV-I, but penile ulcers or concurrent syphilis may increase a man's risk of infection.

Adolescent↗
PubMed1989

Modelling the risk of adult T-cell leukemia/lymphoma in persons infected with human T-lymphotropic virus type I.

Adult T-cell leukemia/lymphoma (ATL), a malignancy of mature CD4-positive lymphocytes, has been etiologically linked to the human retrovirus HTLV-I. Although a long latent period is suggested from migrant studies, little prospective information on the risk of developing ATL among persons with HTLV-I infection is available. We present here a model for ATL risk based upon age- and sex-specific HTLV-I seroprevalence data from a cross-sectional survey of 13,000 Jamaicans and ATL incidence data from a 2 1/2-year case-control study. By examining the age-specific incidence of ATL relative to both adult and childhood-acquired seropositivity versus childhood-acquired seropositivity alone, we provide evidence in support of the hypothesis that childhood infection with HTLV-I is important to the development of ATL. Using this model, the cumulative lifetime risk of ATL for those infected before age 20 is estimated to be 4.0% for males and 4.2% for females. Under this hypothesis, HTLV-I-associated diseases with shorter latent periods, such as tropical spastic paraparesis, should have a higher incidence in adult females than in adult males.

Adolescent↗
PubMed1989

Comparison of a human T-cell lymphotropic virus type I strain from cerebrospinal fluid of a Jamaican patient with tropical spastic paraparesis with a prototype human T-cell lymphotropic virus type I.

The isolation and characterization of a human T-cell lymphotropic retrovirus related to human T-cell lymphotropic virus type I (HTLV-I) from cerebrospinal fluid of a Jamaican patient with tropical spastic paraparesis is described. The virus isolate is a typical type C retrovirus as seen by electron microscopy and is related to prototype HTLV-I isolated from patients with adult T-cell leukemia but is not identical to this prototype HTLV-I as seen by restriction enzyme mapping.

Aged↗
PubMed1988

Molecular epidemiology of HTLV-I-associated non-Hodgkin's lymphomas in Jamaica.

As part of epidemiologic studies of human T-lymphotropic virus (HTLV)-I-associated malignancies in Jamaica, the authors evaluated 26 patients with non-Hodgkin's lymphoma for the presence of integrated HTLV-I provirus in their malignant cells. Fifteen of 26 patients had integrated provirus. All 15 also were HTLV-I antibody positive. Eleven patients did not have integrated provirus, and all 11 were antibody negative. All of the antibody-positive cases had onset of their disease in adulthood (age range, 21-57 years) as opposed to the broad age range of negative cases (4-66 years). Clinical features which were more common in provirus positive than negative patients included leukemic phase, skin involvement, and hypercalcemia, which are all features frequently seen in HTLV-I-associated adult T-cell leukemia/lymphoma (ATLL). The presence of skin involvement, circulating malignant cells, abnormal liver function tests, or the presence of two or more of these four features were statistically significantly different between virus-positive and virus-negative cases. Although the survival of positive cases (6 months) was shorter than that of negative cases (9 months), this was not statistically significant. The only significant determinant of survival was hypercalcemia, with those who developed hypercalcemia at some point in their disease course, independent of their HTLV-I status, surviving a mean of 5 months as compared to a mean of 17.5 months in those who never became hypercalcemic. The six HTLV-I-positive lymphomas that underwent cell typing were all primarily OKT4 positive, whereas two HTLV-I antibody-negative cases that were typed were B-cell lymphomas.

Antibodies, Viral↗
PubMed1988

Lack of relation between human T-lymphotropic virus type I infection and systemic lupus erythematosus in Jamaica, West Indies.

To determine whether systemic lupus erythematosus (SLE) is associated with human T-lymphotropic virus, type I (HTLV-I) infection in Jamaica, an endemic area for the virus, we studied 63 patients with SLE at the University Hospital of the West Indies in Kingston. Antibodies to HTLV-I were measured by an enzyme-linked immunosorbent assay (ELISA) technique using purified disrupted whole virus as antigen, with confirmation by p24 protein RIA or competitive binding. Four of 63 SLE patients were HTLV-I seropositive (6.3%). There was no evidence for excess HTLV-I infection in SLE patients when their age- and sex-standardized HTLV-I seroprevalence rate was compared to that of a large group of healthy food service employees. None of 13 patients with rheumatoid arthritis were seropositive for HTLV-I. We conclude that HTLV-I infection does not appear to be linked with SLE in Jamaica.

Adolescent↗
PubMed1988

Human immunodeficiency virus and human T-lymphotropic virus type I infection among homosexual men in Kingston, Jamaica.

From August 1985 through January 1986, 125 homosexual or bisexual men from the Kingston area were enrolled in a study to evaluate risk factors for infection with human immunodeficiency virus (HIV) and human T-lymphotropic virus type I (HTLV-I). Twelve men (10%) were seropositive for HIV and 6 (5%) for HTLV-I; 1 man had possible coinfection with HIV and HTLV-I. One third of the men reported having had homosexual encounters with foreign visitors or while travelling outside Jamaica, and sexual contact with men in the U.S. was weakly associated with HIV infection (p = 0.11). The median number of partners was 12 per year (range 0-135) and a greater number of homosexual partners per year was associated with HIV seropositivity (p = 0.01). HIV seropositives also were more likely to have a history of lymphadenopathy (p = 0.07). For HTLV-I, there were no obvious risk factors identified, and age-adjusted seroprevalence was not significantly higher than that of heterosexual men. Compared to studies of homosexual men in the U.S. prior to the advent of extensive AIDS education, the Jamaican homosexual population was more sexually conservative. Despite this circumstance, HIV appears to have entered this population via sexual contact with foreign men and spread efficiently among men with a greater number of sexual partners. The frequency of bisexuality (65/125 men) and the 11% HIV prevalence in bisexual men suggest that secondary infection of female sexual partners may occur.

Acquired Immunodeficiency Syndrome↗