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Biomedical subjects

R B Hayes

Publications and source records attributed to R B Hayes.

139 records · Page 8Linked to original sources
PubMed1986

Cancer of the nasal cavity and paranasal sinuses, and formaldehyde exposure.

This case-control study of nasal and paranasal sinus tumors, in males diagnosed between 1978 and 1981 in the Netherlands, was designed to identify environmental risk factors. Special attention was given to assessing any association between nasal cancer and an occupational history of possible formaldehyde exposure while taking into account histologic type of tumor, history of tobacco use, and occupational exposure to wood dust. Of the 116 cases and 259 controls identified, interviews were completed for 91 (78%) of the cases and 195 (75%) of the controls. Adenocarcinoma was strongly associated with a history of high wood dust exposure (RR = 27.0). Two independent assessments of the association between possible formaldehyde exposure and the risk for nasal cancer were carried out (Assessments A and B). By Assessment A the relative risk for nasal cancer associated with possible formaldehyde exposure was 2.5 and by Assessment B it was 1.9. The risk appeared to be most strongly associated with squamous-cell carcinoma and could not be attributed to differences between cases and controls in age, smoking habits, or wood dust exposure. By its retrospective nature, the classification of formaldehyde exposure in this study is not based on known exposures to formaldehyde but on assessment of employment in jobs where formaldehyde exposure is thought possible. Given the limitations of the study, the authors do not consider that it provides conclusive evidence of a carcinogenic effect for formaldehyde, but that it indicates a need for further research--particularly into formaldehyde and squamous carcinoma of the nose.

Adenocarcinoma↗
PubMed1986

Comparison of contemporaneous and retrospective estimates of food consumption made by a dietary history method.

In 1983 the relative validity of a retrospective dietary history method was assessed against a current dietary history taken seven years previously in 1976 and a second current dietary history taken in 1983. In total, 44 men and 58 women, aged 38 to 62 years, participated in the study. For energy intake and for most nutrients, the relative difference between the results obtained with the retrospective dietary history and the current dietary history in 1976 was below 15% and for six of the 11 nutrients below 10%. When the three macronutrients (protein, fat, and carbohydrate) were expressed as a proportion of energy intake, the relative difference was also below 10%. Similar results were found for food groups. The data obtained retrospectively correlate rather well with the results of the current dietary history taken in 1983, suggesting an effect of contemporaneous food habits on retrospective reporting.

Adult↗
PubMed1986

Wood-related occupations, wood dust exposure, and sinonasal cancer.

A case-control study was conducted to examine the relations between type of woodworking and the extent of wood dust exposure to the risks for specific histologic types of sinonasal cancer. In cooperation with the major treatment centers in the Netherlands, 116 male patients newly diagnosed between 1978 and 1981 with primary malignancies of epithelial origin of this site were identified for study. Living controls were selected from the municipal registries, and deceased controls were selected from the national death registry. Interviews were completed for 91 (78%) cases and 195 (75%) controls. Job histories were coded by industry and occupation. An index of exposure was developed to classify the extent of occupational exposure to wood dust. When necessary, adjustment was made for age and usual cigarette use. The risk for nasal adenocarcinoma was elevated by industry for the wood and paper industry (odds ratio (OR) = 11.9) and by occupation for those employed in furniture and cabinet making (OR = 139.8), in factory joinery and carpentry work (OR = 16.3), and in association with high-level wood dust exposure (OR = 26.3). Other types of nasal cancer were not found to be associated with wood-related industries or occupations. A moderate excess in risk for squamous cell cancer (OR = 2.5) was associated with low-level wood dust exposure; however, no dose-response relation was evident. The association between wood dust and adenocarcinoma was strongest for those employed in wood dust-related occupations between 1930 and 1941. The risk of adenocarcinoma did not appear to decrease for at least 15 years after termination of exposure to wood dust. No cases of nasal adenocarcinoma were observed in men whose first exposure to wood dust occurred after 1941.

Adenocarcinoma↗
PubMed1984

Aflatoxin exposures in the industrial setting: an epidemiological study of mortality.

Mortality occurring between 1963 and 1980 in a small cohort (N = 71) of Dutch oil-press workers exposed between 1961 and 1969 to aflatoxins primarily via the respiratory route, was assessed and compared to that of a similar group of unexposed workers (N = 67). For the entire period of study, the observed mortalities for total-cancer and respiratory cancer were higher than expected in the aflatoxin-exposed group. Mortality observed in the comparison group was within the expected range. While two deaths in the exposed group were attributed to non-malignant liver disease, no primary liver tumours were observed. The greatest difference between observed and expected mortality was in the period between 1963 and 1968.

Adult↗
PubMed1983

An assessment of the relative validity of retrospective interviewing for measuring dietary intake.

The relative validity of a method for determining dietary intake four years previously was assessed. In May 1981, 79 people (46 women and 33 men, aged 29-69 years) were interviewed by use of the dietary history method concerning dietary intake in 1977. These results were compared with those obtained in this same group by means of a seven-day record in February 1977. For daily intake of energy and selected nutrients, the differences in mean intake were generally below 10%, while for six examined food groups, larger differences in the median estimates were noted. The results provide evidence that retrospectively collected dietary data have some meaningfulness, although questions remain concerning whether the retrospective dietary history method is sufficiently valid for use in a particular epidemiologic study.

Adult↗
PubMed1979

Mortality in chromium chemical production workers: a prospective study.

Mortality among male employees was studied in a chromium chemical production plant, part of which was rebuilt in 1950-51 and the remainder in 1960, to reduce exposure to chromium bearing dusts. Of 2 101 employees initially employed between 1945 and 1974 and having worked at least 90 days, the vital status of 88% was ascertained, as of mid-1977. Lung cancer mortality for hourly workers initially employed between 1945 and 1959 was significantly higher than in the comparison Baltimore City population (SMR = 2.0), yet it was lower than that reported in previous studies of this industry. A dose response effect was evident from the relationship between duration of employment and mortality. The lung cancer mortality among those employed for three or more years exclusively in the new facility was similar to that observed for such long-term workers in other parts of the plant. Specific job positions were examined. A history of employment in the Bichromate and Special Products Department (production of chromic acid and other products), known as the 'wet end', was associated with the increased lung cancer mortality in contrast to the Mill and Roast Department, known as the 'dry end'. Because of the long latency period associated with chromium exposure and cancer, it was not possible to adequately assess the risk of cancer for workers initially employed after 1960. Methodological issues related to these findings are discussed.

Chemical Industry↗
PubMedDate not supplied

Preparation-induced errors in EPR dosimetry of enamel: pre- and post-crushing sensitivity.

Polyakov et al. (1995) showed errors in dose estimation as a function of grain size for enamel grains given beta irradiation after crushing. We tested the effect of gamma irradiation applied to the specimens before and after crushing. We confirmed Polyakov's observations and found that post-crushing irradiation altered the slope of the dose-response curve of the hydroxyapatite signal and produced a grain-size-dependent offset. No changes in the slope of the dose-response curve were seen in enamel caps irradiated whole before crushing.

Dental Enamel↗
PubMedDate not supplied

Genetic susceptibility and occupational cancer.

This review describes statistical models for the biological interaction of susceptibility genes and environmental exposures, as observed in epidemiologic studies. The importance of metabolic transformation of industrial carcinogens and the potential role of genetic polymorphisms in metabolic enzyme activity are outlined. Several genetic polymorphisms have been associated with cancer risk, but the link with the relevant exposures has only infrequently been specified. For example, studies show that slow N-acetylation increased bladder cancer risk among workers exposed to some arylamines, as found among dye workers in England, but that this effect does not hold for benzidine exposure. This link of a genetic susceptibility factor with cancer risk due to some aromatic amines, but not to others, illustrated the specific nature of metabolic environment/gene interactions. Epidemiologic studies to investigate the role of genetic susceptibility in cancer development promise to further the identification of human carcinogens by focusing on susceptible individuals and, in turn, to enhance understanding of human cancer by relating cancer risk in populations to underlying biologic processes. Occupational studies are key to this effort.

Carcinogens↗
PubMedDate not supplied

No point mutation but a codon 31ser-->arg polymorphism of the WAF-1/CIP-1/p21 tumor suppressor gene in nasopharyngeal carcinoma (NPC): the polymorphism distinguishes Caucasians from Chinese.

Mutational inactivation of the p53 tumor suppressor gene is an infrequent event in human nasopharyngeal carcinoma (NPC), a malignancy showing a high incidence in southern China and southeast Asia. To examine the possible involvement of an activated p53 pathway in nasopharynx carcinogenesis, we have screened primary NPC biopsies for possible point mutations in WAF-1/CIP-1/p21, an effector gene transcriptionally regulated by and functioning as a mediator of the p53 tumor suppressor gene. Mutations in WAF-1/CIP-1/p21 might mimic p53 mutations in tumors having wild-type p53 such as most NPCs. The mutational analysis of WAF/CIP/p21 by PCR-single strand conformational polymorphism-direct sequencing revealed no point mutation in 41 primary NPC biopsies. A codon 31ser-->arg polymorphism was, however, detected. A striking difference in the distribution of the serine (WAF-ser) and arginine (WAF-arg) forms of WAF-1/CIP-1/p21 was observed when normal healthy Caucasians and Chinese were compared (P < 0.0001). The majority of Caucasians examined were found to be homozygous for WAF-ser (89%, n = 65), while Chinese living in areas of high NPC incidence show a greater than 86% homozygous or heterozygous WAF-arg (Taiwan, n = 66; Hunan, n = 32). The two forms of WAF-1/CIP-1/p21 were examined for potential functional differences in their ability to inhibit cyclin-dependent kinases and tumor cell growth. No significant differences were detected. Furthermore, no association between WAF-1/CIP-1/p21 genotype and NPC risk was observed in a case-control study of 76 NPC cases and 66 normal controls conducted in Taiwan.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Cytogenetic effects of formaldehyde exposure in students of mortuary science.

The effect of low-level exposure to formaldehyde on oral, nasal, and lymphoycte biological markers was studied prospectively in a group of 29 mortician students who were about to take a course in embalming. During the 85-day study period, the subjects performed an average of 6.9 embalmings and had average cumulative formaldehyde exposures of 14.8 ppm-h, with an average air concentration of 1.4 ppm during embalming. Since the average time spent embalming was 125 min, formaldehyde exposures calculated as an 8-h time-weighted average were 0.33 ppm on days when embalmings were done, which was less than the Occupational Safety and Health Administration permissible exposure limit of 0.75 ppm. Epithelial cells from the buccal area of the mouth showed a 12-fold increase in micronucleus frequency during the study period, from 0.046 +/- 0.17/1000 cells preexposure to 0.60 +/- 1.27/1000 cells at the end of the course (P < 0.05). Nasal epithelial micronuclei increased 22%, from 0.41 +/- 0.52/1000 cells to 0.50 +/- 0.67/1000 cells (P = 0.26). In blood cells, the frequency of micronucleated lymphocytes increased 28%, from 4.95 +/- 1.72/1000 cells to 6.36 +/- 2.03/1000 cells (P < 0.05), while sister chromatid exchanges decreased 7.5% (P < 0.05). A dose-response relationship was observed between cumulative exposure to formaldehyde and increases in buccal micronuclei in the 22 male subjects but not in the 7 female subjects. We conclude that low-level exposure to formaldehyde is associated with cytogenetic changes in epithelial cells of the mouth and in blood lymphocytes. These cytogenetic effects may be useful as markers of biologically effective dose.

Adult↗
PubMedDate not supplied

Misclassification of genetic susceptibility biomarkers: implications for case-control studies and cross-population comparisons.

Phenotype and genotype markers of genetic susceptibility are of increasing interest in case-control studies of cancer. It is well established that bias to the odds ratio is caused by less-than-perfect assay sensitivity and specificity and varies with risk factor prevalence. As such, the observed variation in odds ratio between studies of genetic markers and cancer risk may be real, or may be attributed, in part, to variation in assay accuracy or in risk factor prevalence (e.g., prevalence differences between racial groups). The latter can be a particular concern when the prevalence of the "at risk" polymorphism in one or more populations is either very high (e.g., > 85%) or very low (e.g., < 15%). For example, even very high sensitivity (e.g., 98%) can produce substantial bias to the odds ratio when the risk factor prevalence is high. Under some prevalence conditions, however, assays with only moderate accuracy are sufficient and result in minimal bias to the odds ratio. Understanding misclassification in the context of marker prevalence may help to explain disparate findings in the literature and should assist investigators in selecting markers that are appropriate for future studies.

Bias↗
PubMedDate not supplied

Occupational epidemiologic study design and application.

Occupational epidemiologic investigations have provided, and will continue to provide, important information to understand environmental causes of disease. High-quality investigations designed to test hypotheses have several requirements. They must include valid quantitative assessments of exposure, some information on lifestyle risk factors, and include biologic monitoring and marker components whenever possible. Availability of these data allows a clear evaluation of potential confounders and biases, assessment of interaction among risk factors, and provides the opportunity to identify susceptible subgroups.

Bias↗