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Biomedical subjects

D B Thomas

Publications and source records attributed to D B Thomas.

At least 217 records · Page 12Linked to original sources
PubMed1979

Asbestos, dental X-rays, tobacco, and alcohol in the epidemiology of laryngeal cancer.

A case-control study of 47 laryngeal cancers in males of three counties of Washington State was conducted. Personal interview was used to obtain information on smoking, alcohol use, exposure to asbestos, and other substances, and x-rays of the head and neck area. Smoking and alcohol consumption were found to increase risk of laryngeal cancer independently, with a clear dose-response relationship. Neither asbestos exposure nor exposure to other substances was found to significantly increase the risk of laryngeal cancer, although the relative risk with asbestos exposure was 1.75. Lifetime history of exposure to dental x-rays on five or more occasions was associated with significantly increased risk of laryngeal cancer among heavy smokers but not among light smokers. The importance of tobacco and alcohol in the epidemiology of laryngeal cancer was re-affirmed, the importance of asbestos exposure was brought into question, and a possible relationship of laryngeal cancer with exposure to dental x-rays among heavy smokers was demonstrated.

Aged↗
PubMed1979

The phase III clinical evaluation of LAAM: I. Comparative epidemiology of mortality in LAAM and methadone.

Two essential points can be made: 1. Mortality experience in the LAAM Phase II trial follows closely the experience of methadone maintenance though these data should be considered preliminary. 2. Generally, the influence of time in treatment on the probability of mortality is strong enough to warrant avoiding comparisons between mortality rates where this parameter is not controlled.

Clinical Trials as Topic↗
PubMed1979

Epidemiologic studies of cancer in minority groups in the western United States.

Of 13 cancers that tend to occur at lower rates in aboriginal Americans or in the native lands of Japanese, Chinese, and Spanish-speaking persons than in United States whites, rates for all but one (laryngeal) have increased in migrants to the United States. In addition to leukemia, these 13 cancers include neoplasms that have been related, at least in part, to a diet high in animal fats or proteins (colon and rectum cancer); reproductive and endocrinologic factors and a diet high in animal fats or protein (prostate, ovary, corpus uteri, breast, and testis cancer); chemical carcinogens (lung, larynx, bladder, and pancreas cancer); and a common infectious agent that, like polio viruses, causes clinically overt disease with a frequency directly related to age of patient at initial infection (Hodgkin's disease). Of 9 cancers that occur at higher rates in aboriginal Americans or in one or more of the native lands of migrants than in United States whites, the rates of 5 tend to decrease in migrants. These include cancers that may be related to food preservation (stomach cancer); products of microorganisms that may contaminate foods (esophagus and liver cancer); and infectious agents (nasopharynx, cervix uteri, and liver cancer). In addition, rates of cancer of the thyroid are high in aboriginal Americans; those of the gallbladder are high in individuals of native American ancestry and in Japanese; incidence of salivary gland tumors is high in Alaskan natives and Colombians; and rates of kidney cancer are high in Alaskan natives. Five types of epidemiologic studies are described that should be conducted in the migrants and in their countries of origin and adoption to elucidate further the etiology of various neoplasms.

Adult↗
PubMed1978

Relationship of herpes simplex virus type-2 antibodies and squamous dysplasia to cervical carcinoma in situ.

Serum specimens from 75 women with cervical carcinoma in situ, 84 with squamous dysplasia, and 132 controls, who had previously been interviewed and tested for complement fixing antibodies against a number of organisms, were analyzed for HSV-2 antibodies. Carcinoma in situ and severe dysplasia were associated with HSV-2 antibodies. Mild dysplasia was related to evidence of prior infection by Trichomonas vaginalis, adenoviruses, and Mycoplasma pneumoniae, plus a history of vaginal discharge. Severe dysplasia was less strongly related to these variables. The relative risk of dysplasia increased with the number of different pathogens by which a woman had been infected. It is concluded that HSV-2 may be a cause of carcinoma in situ; that much dysplasia is a nonspecific reaction of the cervical epithelium to chronic inflammation; and that dysplastic lesions that are caused by HSV-2, and hence may be a precursor to carcinoma in situ, tend to be distinguished by their severity.

Adolescent↗
PubMed1978

Role of exogenous female hormones in altering the risk of benign and malignant neoplasms in humans.

The epidemiological and clinical evidence for various forms of exogenous estrogens altering the risk of neoplasms of the female genital system, breast, and liver are reviewed and evaluated. It is virtually certain that in utero exposure to diethylstilbestrol can cause clear cell adenocarcinomas of the vagina and cervix. There is strong evidence that various estrogens given for treatment of menopausal symptoms can cause endometrial carcinoma and that sequential oral contraceptives probably also do so. Oral contraceptives very probably reduce the risk of both cystic disease and fibroadenoma of the breast and increase the risk of liver cell adenomas. Studies to date do not provide consistent and convincing evidence that any form of exogenous estrogen alters the risk of cancers of the breast or ovary or that oral contraceptives alter the risk of cervical neoplasia or focal nodular hyperplasia of the liver, although recent reports suggest that continued vigilance is warranted. Specific topics requiring further epidemiological investigation are suggested.

Adenocarcinoma↗
PubMed1977

A study of five year old children born after elective induction of labour.

A controlled retrospective study of some short-term and long-term effects of elective induction of labour was conducted. There did not appear to be any increase in the incidence of maternal complications during labour, or of neonatal problems in the induced-labour group compared with the remainder of the mothers in the hospital. In the follow-up phase of the study, two treatment groups of children who were delivered after amniotomy and amniotomy plus the administration of oxytocin were compared with each other, and with a control group of children born after spontaneous labour. The children were assessed at the age of five years on verbal and non-verbal subtests of a standardized intelligence scale, tests of gross motor and fine motor coordination, and auditory and visual tests. A full physical examination was also performed. No statistically significant differences nor trends of clinical interest were found between the groups on any measure.

Birth Weight↗
PubMed1977

History and status of the Cancer Surveillance System of Western Washington.

A cancer registry for a population of over 2 million people was established in 1973. Although the population is predominantly white, the presence of people of Oriental stock provides a potential for migrant studies and international comparisons. Over 7,900 resident cancer cases are detected annually, and a good system for evaluating completeness of reporting and quality of collected data has been devised. To utilize the resources that the registry represents, we have a competent staff of epidemiologists and biostatisticians with academic appointments at the University of Washington and interests in cancer etiology, evaluation of care, and teaching.

Adolescent↗
PubMed1976

Interactions of murine leukemia virus (MuLV) with isolated lymphocytes. III. Alterations of splenic B and T cells in Friend virus-infected mice.

Lymphoid tissues of mice infected with murine leukemia virus (Friend) (MuLV-F) were examined for the presence of cellular markers of MuLV-F infection. The Friend virus-associated cell membrane antigen (FVMA) and the virus group-specific antigen (GSA) were detectable on cells from the spleen and, to a lesser degree, on cells from the bone-marrow. In contrast, neither FVMA nor GSA was found in cells from the thymus. Alterations in the B-cell and T-cell spleen populations of MuLV-F-infected mice were then studied. The proportion of Ig-positive cells declined from the initial 45% (in non-infected controls) to about 10% after 2 weeks of infection. A similar decline of theta-positive cells was noted. However, complement-bearing cells (EAC rosettes) declined even more rapidly and became undetectable in the second week after infection. The treatment of spleen cells from MuLV-F-infected mice with anti-FVMA serum plus complement in vitro reduced the number of detectable Ig-positive cells, specifically, whereas the number of theta-positive cells remained unchanged. Furthermore, B and T cells from spleens of infected mice were separated on an affinity column with anti-Ig antibody-coated beads. The initial cell suspension contained about 45% FVMA-positive cells, about 40% Ig-positive cells and about 40% theta-positive cells. Ig+ cells were retained on the column. The theta-positive cell fraction was collected in the eluate and contained very few FVMA-positive cells with some "null" cells. Most of the FVMA-positive cells were retained on the column, which strongly suggested that they were B cells. These results confirm the previous experiments which showed the selective infections of purified splenic B cells by MuLV-F in cultures.

Animals↗
PubMed1976

Cell-cycle, cell-shape mutant with features of the Go state.

A cold-sensitive mutant of CHO cells has features of "reverse transformation" at the non-premissive temperature of 33 degrees C. Cells accumulate at G1 with altered morphology and remain viable and quiescent for more than 40 d. Such cultures are synchronised by a temperature shift back to the permissive 39 degrees C.

Bucladesine↗