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Biomedical subjects

T Hirohata

Publications and source records attributed to T Hirohata.

At least 145 records · Page 8Linked to original sources
PubMed1981

Mutagenicity of smoke condensates induced by CO2-laser irradiation and electrocauterization.

Smoke condensates generated from mucous membrane of the canine tongue irradiated with a CO2 laser showed mutagenicity on Salmonella typhimurium TA98 under metabolic activation with S9 mix. Strain TA100 was not so sensitive to the condensates with or without S9 mix. Smoke condensates from electrocauterization on the mucosa of the canine tongue also showed mutagenic activity on TA98 and TA100 with S9 mix. The revertant number per mg of the smoke condensates from laser irradiation was one-half that of the smoke condensates from electrocauterization (1623 and 3371) in TA98. The mutagenic potency observed was comparable to that of cigarette smoke. The amount of these smoke condensates from 1 g of tissue was equivalent to those from 3--6 cigarettes as to total mutagenicity.

Animals↗
PubMed1980

Associations between cancer incidence and alcohol/cigarette consumption among five ethnic groups in Hawaii.

The average annual age-adjusted incidence rates of cancer for 15 sites were determined for 10 ethnic-sex groups in Hawaii. Consumption rates for cigarettes, beer, wine and hard liquor were also determined for the same 10 groups based on personal interview of a sample of 9920 individuals. Covariance analysis was used to adjust each exposure variable for the other three, and the cancer incidence rates were then linearly regressed on these covariance-adjusted consumption rates. Statistically significant regression coefficients were found for cancer of the tongue/mouth, pharynx, larynx, pancreas, lung, kidney and bladder regressed on cigarette consumption. Eight cancer sites, including tongue/mouth, pharynx, larynx, oesophagus, stomach, pancreas, lung and kidney, had significant positive regression coefficients for beer consumption which could not be explained by outlying values on the scattergram. Significant associations were also suggested between wine consumption and pharyngeal cancer and between hard-liquor consumption and pharyngeal, laryngeal and possibly brain cancer. No association was found between beer consumption and colorectal cancer. Multiple regression analysis with sex, cigarettes and alcoholic beverage as independent variables consistently found sex to be least important in determining cancer risk. This study supports the hypothesis that beer consumption may play a role in cancer risk for several sites. It is suggested that future studies of alcoholic beverages and cancer should examine not only types of alcoholic beverages, but individual brands of each type in an attempt to identify cancer risk due to carcinogens in only certain brands.

Alcohol Drinking↗
PubMed1980

Cancer mortality in a cohort of naval shipyard workers in Hawaii: early findings.

A retrospective cohort study was performed in Hawaii among 4,779 male shipyard workers exposed to asbestos and 2,757 similar male workers without known asbestos exposure. Observed deaths from cancer and other causes in the 2 groups were compared with expected deaths on the basis of the general population of Hawaii by the use of a modified life-table method of analysis. A risk ratio for lung cancer of 1.7 was found for the exposed group after 20 or more years of follow-up. No increased risk for lung cancer was seen in the nonexposed group. These findings could not be attributed to differences in smoking habits in the 2 shipyard groups or between the shipyard groups and the general population. Because the maximum duration of follow-up for this analysis was 24 years, greater risks for lung cancer may be seen in the exposed group when the follow-up period is extended.

Asbestos↗
PubMed1979

Population registries and other record resources for epidemiologic cancer research in the United States and Japan.

On the basis of the author's experience in epidemiologic studies on cancer in both the United States and Japan for the last 15 years, advantages and disadvantages of various record systems that can be utilized for epidemiologic cancer studies in these two countries are compared. Both countries are equally well provided with vital statistics and census records. Descriptive studies can be conducted without difficulties in both countries. For analytic studies, the Koseki record or family registration system in Japan provides an excellent tool in tracing subjects. However, Japanese record systems have problems as to management of hospital records, preservation of death certificates, etc. On the whole, restrospective cohort studies, particularly studies on patients, are more difficult in Japan than in the United States. There appear to be no material differences between these two countires as to case-control studies.

Epidemiologic Methods↗
PubMed1979

Incidence and etiology of lung cancer in the Pacific Basin.

Incidence of lung cancer in the Pacific Basin was either compiled from published reports or computed by the authors. The results showed a great variation in age-standardized annual incidence rates of lung cancer among 10 countries and 17 areas in the Pacific Basin where tumor registry statistics are available. For males the incidence rates ranged from 10 to over 70 and for females from less than 5 to over 30/100,000 population. The reason(s) for the great variation is unclear. Ionizing radiation, carcinogenic chemical substances (e.g., chromium, arsenic compounds, asbestos, etc.), or air pollution are unlikely to be responsible. Because cigarette smoking is known to be a major cause of lung cancer, the authors have suggested that surveys on cigarette smoking be conducted among various populations in the Pacific Basin so that etiologic significance of cigarette smoking for the noted variation can be assessed. In Hawaii such a survey is underway, and a preliminary analysis was made to examine the association between lung cancer and cigarette smoking among five races.

Australia↗
PubMed1978

Survivorship from large bowel cancer among Caucasians and Japanese in Hawaii.

From 1960 through 1973, the Hawaii Tumor Registry identified 781 Caucasian and 1073 Japanese cases of large bowel cancer. Survivorship analysis revealed that Japanese patients had a 32% higher 5-year relative survival rate than Caucasians. Further analyses showed that colon cancer cases did better than rectal cases, and patients diagnosed before 65 years of age fared better than cases diagnosed at an older age. As expected, patients with localized disease lived much longer than those who had more advanced disease. Men and women were similar in their survival from large bowel cancer. Histologic grade of the lesion, socioeconomic variables, behavioral practices and other factors which may affect survivorship by race could not be included in this study. Until such factors are also incoporated in the analyses, the observed results are only suggestive of a racial difference in survivorship.

Age Factors↗
PubMed1977

Leprosy and cancer: a retrospective cohort study in Hawaii.

We used data collected on a retrospective cohort of 1,123 leprosy patients living in Hawaii between 1940 and 1970, to test the hypotheses that patients with lepromatous leprosy, who have an impairment in their cellular immune response, would have an increased risk for cancer and that patients with tuberculoid leprosy, who are immunologically competent, would have a normal or even a reduced cancer risk from beneficial stimulation of their cellular immune system by exposure to the Mycobacterium leprae organisms. Based on the survival analysis method, the results of the study supported the predicted increase in cancer cases among the lepromatous leprosy patients (19 observed, 12.7 expected; risk ratio = 1.5) and the predicted decrease among the tuberculoid leprosy patients (14 observed, 17.8 expected; risk ratio = 0.8); in both groups, the findings were consistent across the five racial categories of the study. However, none of these differences between observed and expected cases was statistically significant at the 5% level. The study provided no support for the alternate hypothesis that chronic antigenic stimulation by the M. leprae organisms might lead to an increase in tumors of the lymphoreticular system.

Adolescent↗
PubMed1977

Adequacy of survey data collected from substitute respondents.

This study examined interview data on personal habits (smoking, drinking and dietary histories) when collected from two sources. A sample of 300 pairs of subjects (mostly husbands and wives) was obtained from an ongoing health survey in Hawaii, and both members of each pair were interviewed separately about the habits of the husband. Care was taken that the members of each pair had no opportunity to communicate with each other between the start and completion of both interviews. The results showed remarkably good agreement in overall mean values between the two groups of respondents. In general, approximately 75% of the pairs agreed within acceptable limits on most items. There was no clear association of the degree of agreement within pairs with a variety of characteristics of the surrogate group, including age, race, level of education, family income, and duration of residence of proportion of meals eaten together with the subject. These findings are encouraging for the use of surrogate respondents in studies of personal habits where direct interviews are not always feasible, or where the use of such substitutes can improve the reppresentativeness and size of the sample.

Adolescent↗
PubMed1977

Diet and exogenous estrogens in three populations at different levels of risk for breast cancer.

A case-control study is being conducted in which a questionnaire is used to collect information on past history of drug usage (including menopausal estrogens) and the normal weekly dietary intake. Breast cancer cases from 3 selected populations (ages 45--74) are identified: 1) the Caucasians in Hawaii, at high risk for breast cancer; 2) the Japanese in Hawaii, at intermediate risk; and 3) the Japanese in Fukuoka, Japan, representing a low-risk population. For each case, a neighborhood and hospital control matched by race and age is interviewed. Attempts are made to verify the drug history with the subject's personal physician, and a subsample of the study population received a repeated dietary interview to assess its reliability. Pathologic slides of the breast cancer cases are reviewed by three consulting pathologists to confirm cancer diagnosis and to identify possible histologic differences in the 3 populations. In all, 200 cases and 400 controls will be interviewed from each study population.

Aged↗
PubMed1977

Epidemiologic cancer research programs of the Cancer Center of Hawaii.

Ongoing epidemiologic cancer research programs are described. These programs were developed by the Epidemiology and Demography Unit, Cancer Center of Hawaii, established in July 1974. During the 15-month period prior to the Pacific Basin Conference, many epidemiologic projects were initiated. Major descriptive, epidemiologic studies were undertaken: a) cancer mortality among the Japanese in Hawaii, adjusted by prefecture-of-origin; b) time trend of mortality rates for 80 causes between 1910--70; c) evaluation of race classification in Hawaii; d) survival analysis; and e) increased lung cancer rates among Japanese migrants in relation to smoking. Major analytic, epidemiologic studies were as follows: a) an international case-control study on breast cancer in relation to diet and exogenous estrogens; b) association between height and weight and various types of cancer; c) a follow-up study of about 9,000 shipyard workers exposed to asbestos; d) an epidemiologic survey on a 2- to 3-% sample population of Hawaii; and e) a follow-up study on leprosy patients in relation to their risks for cancer.

Alcohol Drinking↗