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Biomedical subjects

A S Evans

Publications and source records attributed to A S Evans.

At least 19 recordsLinked to original sources
PubMed1992

The past is prologue: use of serum banks in cancer research.

In this paper, we emphasize the uses of serum banks in cancer research. These include not only case/control studies but also prospective seroepidemiological studies in which the development of a serological marker, such as a viral antibody or viral antigen, can be correlated with the subsequent development of cancer in either an active surveillance program or the use of cancer registries or hospital records. Several different methods of application of the cohort technique are illustrated by studies of hepatitis B antigen and hepatocellular carcinoma and of Epstein-Barr virus in relation to African Burkitt's lymphoma, Hodgkin's lymphoma, and non-Hodgkin's lymphoma. Collections of sera done for one purpose can often be utilized for another purpose, if properly stored and documented. Two examples are tests for human T-cell leukemia virus, type 1, antibody from sera done for a health survey in Barbados approximately 8 years earlier and the use of data determined for a prospective study of the incidence of Epstein-Barr virus infection and infectious mononucleosis in West Point Cadets for psychological factors affecting the development of clinical illness among those infected. Archival materials, such as frozen tissues and paraffin sections, may also now be utilized for identifying genomes of potential oncogenic viruses by the polymerase chain reaction.

Blood Banks↗
PubMed1990

Viruses and cancer. Causal associations.

This review first considered some general problems in establishing causal links between a virus and a human cancer and offered some guidelines in the pursuit of this objective. Second, it reviewed the current causal associations for several candidate oncogenic viruses in relation to the tumors with which they are associated. These include Epstein-Barr virus in relation to Burkitt's lymphoma, nasopharyngeal carcinoma, Hodgkin's disease, and non-Hodgkin's lymphoma; hepatitis B and C viruses in relation to hepatocellular carcinoma; human T-cell leukemia/lymphoma virus type 1 and atypical leukemia/lymphoma; and human papilloma viruses in relation to cervical carcinoma. For some, the causal relationship is strong: hepatitis B virus with hepatocellular carcinoma, and human T-cell leukemia/lymphoma virus with adult T-cell leukemia/lymphoma. For one, the causal relationship is moderate: Epstein-Barr virus with African Burkitt's lymphoma. For others it is incomplete or inconclusive: Epstein-Barr virus with Hodgkin's disease and non-Hodgkin's lymphoma, and hepatitis C virus with hepatocellular carcinoma. Current techniques do not permit an answer for some: human papilloma virus with cervical carcinoma.

Animals↗
PubMed1989

A historical study of human T lymphotropic virus type I transmission in Barbados.

A 1972 historic sera collection from two health districts in Barbados, British West Indies, was evaluated for risk factors and epidemiologic patterns of HTLV-I (human T cell leukemia virus type I) during a time prior to the first report of its discovery in 1980. HTLV-I seroprevalence is 4.2% (43 of 1,012) and is consistent with current estimates in endemic areas in the Caribbean. Age-dependent rise (P less than .01) and higher seroprevalence rates for females (P less than .01) are indistinguishable from the pattern in contemporary Caribbean and Japanese populations. HTLV-I seropositivity was 4 times higher in women (P less than .003) and 2.6 times higher in men (P = .32) with treponemal antibodies, supporting a role for sexual transmission. Children who were positive in a household were more likely to have a seropositive mother than a seropositive father. This pattern is consistent with transmission of the virus from mother to child. Our results document that rates of infection and modes of transmission of HTLV-I are persistent.

Adolescent↗
PubMed1987

A nuclear deoxyribonucleic acid analysis of normal and abnormal vulvar epithelium.

Vulvar and groin skin from 21 women with clinical squamous cell carcinoma of the vulva was compared with that from nine patients with vulvar intraepithelial neoplasia. Feulgen-stained nuclear densitometry showed a constancy of Feulgen-deoxyribonucleic acid (DNA) density in normal epithelium and all subepithelial connective tissue nuclei. At three sites--tumor edge, opposite labia, and perineum--there were significant differences in nuclear chromatin content between the two groups and also as compared with normal epithelium.

Biopsy↗
PubMed1987

The nuclear DNA content of vulvar skin using Feulgen microspectrophotometry and "four-quarter" analysis.

The nuclear DNA contents in subbasal (nonreplicating) cells of 161 vulvar biopsies from 31 patients were studied by Feulgen staining, integrated scanning microspectrophotometry (densitometry) and subsequent "four-quarter" analysis of the measurements. The results showed a constancy of the nuclear DNA content in the nonreplicating cells, regardless of the patient or the biopsy site.

Biopsy↗
PubMed1986

Results of CO2 laser cylinder vaporization of cervical intraepithelial disease in 1234 patients. An analysis of failures.

This report analyses 1234 patients with CIN and non-condylomatous wart virus infection (NCWVI) managed by CO2 laser ablation in the Regional Department of Gynaecological Oncology, Queen Elizabeth Hospital, Gateshead from 1979 to 1983. Thirty-five patients (3%) were lost to follow-up. Of the 1157 patients currently under review and with at least 1 year of follow-up, 44 (3.8%) were laser treatment failures. This group is analysed and the results compared with other series.

Adolescent↗
PubMed1985

Spontaneous resolution of cervical warty atypia: the relevance of clinical and nuclear DNA features: a prospective study.

A selected group of 51 patients with histological features of cervical warty atypia was observed for 1 year. Initial features were compared with a cohort of 50 patients with CIN. Twenty-four patients showed resolution of the warty atypia, in 19 it remained unchanged, and in eight patients CIN or microinvasive disease was present on repeat biopsy. The DNA patterns obtained by tissue imprint of the initial biopsies and subsequent integrated densitometry, using a Vickers M85 scanning densitometer, showed that warty atypias could be objectively distinguished from CIN, but that the method could not predict the group of warty atypias that would resolve. There was no clinical feature or group of features which allowed a means of predicting the outcome of such lesions.

Adult↗
PubMed1985

Epidemiology of Burkitt's lymphoma: other risk factors.

Events surrounding infection and disease in infectious mononucleosis are a model for epidemiological factors that may affect the phase of initiation, the phase of promotion and the phase of tumour development in African Burkitt's lymphoma (BL). Consideration of the circumstances of early Epstein-Barr virus (EBV) infection as the initiator, and of malaria as the promoter, of African BL reveal some shortcomings in the evidence incriminating malaria. Possible factors leading to the emergence of the clinical tumour suggest that other factors may be involved. The absence of EBV and malarial infection in some cases of American BL indicate that they are neither necessary nor sufficient causes of the tumour in all settings.

Africa↗