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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
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↗
PubMed1987

2'-Deoxycoformycin therapy in adult T-cell leukemia/lymphoma.

Six Caribbean patients with histologically and immunologically characterized adult T-cell leukemia/lymphoma (ATL) were treated intravenously (IV) with 2'-deoxycoformycin (DCF) at a dose of 5 mg/m2 on days 1, 2, 8, 15, and 22 with four additional weekly doses to convert any partial responses (PR) to complete responses (CR). Patients were considered eligible for this study if refractory to or relapsed from combination chemotherapy, had a life expectancy of 4 weeks or more, a performance status greater than or equal to 50%, normal renal and hepatic function, and no chemotherapy within 4 weeks. Clinical characteristics of the patients in this study included lymphadenopathy in five patients, skin involvement in four patients, bone marrow infiltration in five patients, and central nervous system involvement in two patients. Circulating ATL cells were present in four patients, and three were hypercalcemic. Of five patients evaluable for response, there was one PR of 1 month, and two minor responses lasting 2 and 3 weeks. The median duration of survival for all treated patients was 3 weeks or more. The DCF was associated with moderate side effects, including conjunctivitis in three patients, nausea and vomiting in two patients, progressive hepatic insufficiency in one patient, and moderate myelotoxicity in three patients. Infections occurred in four patients, including two cases of oral candidiasis and two cases of fatal neutropenic sepsis in patients receiving concurrent intrathecal methotrexate. As a single agent, DCF appears to have limited activity in advanced refractory/relapsed ATL. Studies in the future should explore DCF in combination with other cytotoxic agents as initial therapy in better-risk patients.

Adult↗
PubMed1987

Non-Hodgkin lymphoma in Jamaica and its relation to adult T-cell leukemia-lymphoma.

Of 95 patients consecutively diagnosed with non-Hodgkin lymphoma, 52 (55%) had antibodies to human T-cell leukemia-lymphoma virus, type I. Antibody positivity was strongly associated with skin involvement, leukemia, and hypercalcemia (p less than 0.02). Two patients had systemic opportunistic infections. Neither meningeal nor lung infiltration was detected, and lymph node infiltration was diffuse in all patients. Of 36 patients who received immunophenotypic classifications, 30 had diseases that affected the T-cell system, and the cells of all tested patients with these diseases showed the helper/inducer (T4) phenotype. Twenty-seven of these thirty-six patients were found to have adult T-cell leukemia-lymphoma, and of the 27, 24 had antibodies to HTLV-I. The median duration of survival in patients with adult T-cell leukemia-lymphoma was 17 weeks, but a subgroup of 9 patients had indolent courses and a median survival of 81 weeks, which suggests that the disease has differing expression with courses that range from smoldering and indolent to acute and rapidly fatal. Hypercalcemia was the most important prognostic determinant of adult T-cell leukemia-lymphoma.

Adolescent↗
PubMed1985

Molecular and immunologic analysis of a chronic lymphocytic leukemia case with antibodies against human T-cell leukemia virus.

The human T-cell leukemia virus type-I (HTLV-I) is a unique, exogenous, horizontally transmitted retrovirus which is T-cell tropic, and has been associated with a specific type of aggressive leukemia/lymphoma of mature T-cell origin. In a survey of lymphoid malignancies in Jamaica, antibodies to HTLV-I were also found in 6 of 17 patients with chronic lymphocytic leukemia (CLL), raising the possibility of an etiologic relationship. Further studies were undertaken on one of these patients to clarify the nature of the disease and possible virus relationship. Cell surface marker analysis of her peripheral blood cells documented that the majority of circulating lymphocytes were B-cells. DNA-cloned probe analysis with a complete HTLV-I proviral genome of these peripheral malignant B-cells, was negative for integrated virus. A T-cell line was established in culture from her peripheral blood. The presence of HTLV-I in the cultured T-cell line was established by the detection of expressed viral specific gag protein p-19 and proviral DNA. Thus, a B-cell lymphoid malignancy can occur in the presence of HTLV-I infected T-cells, suggesting the possibility of an indirect leukemogenic mechanism.

Aged↗
PubMed1985

Seroepidemiologic studies of human T-cell leukemia/lymphoma virus type I in Jamaica.

The prevalence of HTLV-I antibodies was evaluated in Jamaica among persons with various malignant, infectious, autoimmune and hematologic disorders and in clinically normal persons. Results document that: (1) the prevalence of HTLV-I antibodies in this population increases with age; (2) overall, there is no significant difference in the antibody prevalence between males and females; (3) antibody-positive individuals are born in all major regions of the island and geographical variance in antibody prevalence by place of birth was not prominent; (4) there is further confirmation of the high prevalence of HTLV-I antibody-positive lymphomas in Jamaica; and (5) the prevalence of HTLV-I antibodies in hemophiliacs, patients with chronic lymphocytic leukemia (CLL), myelogenous leukemias, and patients with breast cancer is higher than in the age-matched population without malignancies, although none of these differences were statistically significant. The increased prevalence in hemophiliacs is most likely related to their frequent transfusion with blood products, but it has not yet been determined whether the prevalence in patients with other diseases is related to their diseases or other as yet undefined factors in common.

Adolescent↗
PubMed1979

Glucose-6-phosphate dehydrogenase deficiency and neonatal jaundice in Jamaica.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency was detected in 16 (69.6%) of a group of 23 neonates who had unexplained moderate or severe jaundice. This proportion is significantly more than the 9.4% observed or the 22.2% expected in Jamaican neonates who are not moderately or severely jaundiced (P less than 0.003), and significantly more than the 12.6% observed or the 21.0% expected in older Jamaican children and adults (P less than 0.003). Phenobarbitone therapy and phototherapy reduced the need for exchange transfusion but this was necessary in eight patients. Two babies developed kernicterus and one died. On the other hand, only two of 21 neonates who were identified as G6PD deficient at birth subsequently became moderately or severely jaundiced, and this could be attributed to other causes in both cases. These findings indicate that apparently spontaneous neonatal jaundice is important in infants who have the G6PD A--enzyme. However, the jaundice is probably precipitated by unknown factors to which the G6PD deficient neonate is more susceptible than the infant who is not G6PD deficient. THere is also a slightly increased incidence of G6PD deficiency in neonates who develop jaundice because of ABO or Rh(D) iso-immune disease, infection or prematurity.

Adolescent↗