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Biomedical subjects

T Hirohata

Publications and source records attributed to T Hirohata.

At least 109 records · Page 6Linked to original sources
PubMed1989

Identification of mutagens in Japanese pickles.

A total of 108 samples of pickles, which were produced in districts with high and low incidences of stomach cancer in Japan, were extracted with methanol-chloroform. The extracts were bioassayed with Salmonella tester strains. The pickles produced in the high-cancer-incidence district were more mutagenic than those produced in the low-incidence district. The most mutagenic sample among 24 pickle specimens collected in the high-incidence district induced 130 revertants/mg of the crude extract for strain TA98. The mutagenic compounds were purified, and 2 flavonols, quercetin and rhamnetin, were identified as the major mutagens in the pickles by gas chromatography-mass spectrometry. The quantities of the 2 compounds were determined as 6.60 mg for quercetin, and 1.96 mg for rhamnetin per gram of the crude extract. The mutagenic activities of the pickles produced in the 2 districts were closely related to the amounts of quercetin in them.

Biotransformation↗
PubMed1989

[Basilar bifurcation aneurysm associated with internal carotid artery occlusion. Report of two cases].

Two cases of subarachnoid hemorrhage caused by rupture of a basilar bifurcation aneurysm associated with occlusion of the internal carotid artery (ICA) at the neck are presented. Case 1, a 71-year-old female, was hospitalized in a coma. Angiography demonstrated occlusion of the bilateral ICA, collateral blood supply through the branches of the foramen rotundum or vidian artery from the maxillary arteries and right posterior communicating artery, and a saccular aneurysm at the basilar bifurcation. The patient died 1 month later following rerupture of the aneurysm. Case 2, a 64-year-old male, was hospitalized for drowsiness. Angiography showed occlusion of the right ICA, collateral blood supply through a tortuous artery (a vidian artery), and a large aneurysm at the basilar bifurcation. Posterior circulation supplied anteriorly through the right posterior communicating artery. The patient died 1 month later because of rerupture of the aneurysm. Laminar thrombosis of the right ICA and an anastomotic vessel, seemingly a branch of the foramen rotundum or a vidian artery, were demonstrated by autopsy. The combination of cerebral aneurysm and collateral circulation is extremely rare in cases of occlusion of the ICA. The two cases described here suggest that hemodynamic stress is an important factor in the formation of cerebral aneurysms.

Aged↗
PubMed1989

[Effects of 3-methylsulphonyl-4,5,3',4-tetrachlorobiphenyl and 7,8-benzoflavone on aryl hydrocarbon hydroxylase activity].

First, we examined the effects of 3-methylsulphonyl-4,5,3',4',-tetrachlorobiphenyl (3-MSF-TCB, 1.5 ppm) and 7,8-benzoflavone (ANF, 1.4 ppm) on aryl hydrocarbon hydroxylase (AHH) activity in cultured human lymphoblastoid cells and we have obtained the following results: (1) 3-MSF-TCB preferentially inhibited the enzyme activity induced by 2,3,4,7,8-pentachlorodibenzofuran (PenCDF) or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and slightly stimulated the enzyme activity induced by 3-methylcholanthrene (MC). (2) ANF reduced well the AHH activities induced by all the three enzyme inducers and more strongly inhibited the PenCDF- or TCDD-induced enzyme activity (about 89%). (3) About 64 and 76% of basal (uninduced) AHH activity was lowered by 3-MSF-TCB and ANF, respectively. Second, we investigated the effect of 3-MSF-TCB (1.5-45 ppm) and ANF (1.4-42 ppm) on AHH activity of hepatic microsomes from the Ah nonresponsive (DDD) and responsive (C3H) strains of mice and we have got the following results: (1) 3-MSF-TCB and ANF enhanced or reduced the enzyme activity depending on both their concentrations and kinds of microsomes, namely, those prepared from untreated mice (control-microsomes) and mice treated with MC (MC-microsomes) or TCDD (TCDD-microsomes). (2) ANF showed higher potency for both the enhancement and the inhibition of the enzyme activity than 3-MSF-TCB. (3) The AHH activity of TCDD-microsomes seemed to be more greatly reduced with either 3-MSF-TCB or ANF than that of MC-microsomes. (4) The effects of 3-MSF-TCB and ANF on the enzyme activity of MC-microsomes of DDD mice and of control-microsomes of C3H mice.

Animals↗
PubMed1989

[Introduction of the information processing system of medical examinations of yusho patients and some results obtained by the 1986 survey].

Information processing system for newly established, unified medical examinations of yusho patients which started in September 1985 was presented. Some comparative analysis was also shown on the "important findings" in yusho patients residing in Fukuoka or Nagasaki prefecture. In the 1986 survey, Fukuoka male patients showed higher percentages of pigmentation in toe nail, gingiva and palpebral conjunctiva than Nagasaki (p less than 0.01), whereas Nagasaki male patients showed higher percentages of pigmentation in buccal and lip mucosa. Average concentration of PCB in blood was higher in Nagasaki male patients (6.79 ppb) than in Fukuoka patients (4.39 ppb), the difference being significant at 1% level.

Adolescent↗
PubMed1989

[Effects of dioxin congeners on aryl hydrocarbon hydroxylase activity].

In this study, we examined the effect of 1,3,6,8-tetrachlorodibenzo-p-dioxin (1,3,6,8-TCDD), octachlorodibenzo-p-dioxin (OCDD) and 2,4,6,8-tetrachlorodibenzofuran (2,4,6,8-TCDF) on aryl hydrocarbon hydroxylase (AHH) activity in cultured human lymphoblastoid cells. These compounds are considered to be no or less toxic isomers of polychlorinated dibenzo-p-dioxins (Dioxins) and polychlorinated dibenzofurans (Dibenzofurans). At a concentration of 90 ppb, 1,3,6,8-TCDD induced the enzyme activity about 2 times over the basal (untreated) AHH activity and 2,4,6,8-TCDF reduced the basal enzyme activity by about 40%. At a concentration of 5 ppb, OCDD enhanced the basal AHH activity by about 30%. In case of simultaneous treatment of 1,3,6,8-TCDD, OCDD or 2,4,6,8-TCDF with highly toxic 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD), at a concentration of 7.5 ppb of each compound, the AHH activities induced by 1,3,6,8-TCDD plus 2,3,7,8-TCDD and OCDD plus 2,3,7,8-TCDD were about 25% and 43%, respectively, higher than that induced by 2,3,7,8-TCDD alone. On the contrary, at the same concentration, the enzyme activity treated with 2,4,6,8-TCDF plus 2,3,7,8-TCDD were about 30% less than that treated with 2,3,7,8-TCDD alone. It has been reported that the AHH inducibility of Dioxins and Dibenzofurans correlates well with their toxic potency. Hence, taking the results of this study into account, we should clarify the biological and/or health consequences of the mixed contamination of no or less toxic and highly toxic congeners of Dioxins and Dibenzofurans by animal experiments and epidemiological studies.

Aryl Hydrocarbon Hydroxylases↗
PubMed1988

Blood transfusion, alcohol consumption, and cigarette smoking in causation of hepatocellular carcinoma: a case-control study in Fukuoka, Japan.

In the present study, we investigated the association between hepatocellular carcinoma (HCC) and hepatitis B virus infection (HBV), blood transfusion and drinking and smoking habits by comparing 124 HCC cases and 250 controls. We confirmed a very high relative risk (RR), i.e. 31.0 (P less than 0.001), among persons who were positive for serum hepatitis B surface antigen (HBsAg). However, the prevalence of serum HBsAg positives among our cases was only 21%, about half of those reported earlier, indicating a role of other etiological factors. Those who have a history of blood transfusion showed a significantly elevated RR of 3.0 (P less than 0.001) or 4.9 (P less than 0.001), and most of them (85%) were non-carriers of HBV. Thus, the past history of blood transfusion is an important risk factor among the Japanese. Unidentified non-A, non-B hepatitis viruses in transfused blood probably play a significant role in causing HCC. We estimated that 15% of male HCCs were attributable to blood transfusion. A positive relationship between alcohol consumption and HCC was detected, particularly among HBsAg-negative subjects with no history of blood transfusion who had drunk heavily in their younger years. RR estimates were not great (e.g., heavy drinkers: 2.5), but a substantial proportion of HCC may be attributed to drinking because of common drinking habits among Japanese males. Smoking was also found to have a positive association, but the relationship at a young age was less clear, and further investigation is needed to clarify the etiological role of smoking.

Adult↗
PubMed1988

Influence of alcohol intake, cigarette smoking, and occupational status on idiopathic osteonecrosis of the femoral head.

An epidemiologic study compared 112 patients with idiopathic osteonecrosis (ON) of the femoral head having no history of systemic corticosteroid use and 168 hospital controls. Patients and controls were matched for gender, age, ethnicity, hospital, and time of initial diagnosis. The role of alcohol intake, cigarette smoking, and occupational status was assessed in relation to the development of ON. The relative risk (RR), the measure of association between ON and the risk factors, was statistically adjusted for the potential confounding effects of other factors by the conditional logistic regression model. An elevated risk for regular drinkers (RR = 7.8, p less than 0.001) and a clear dose-response relationship was noted (test for trend; p less than 0.001): the RRs were 3.3, 9.8, and 17.9 for current consumers of less than 400, 400-1000, and greater than or equal to 1000 ml/week of alcohol, respectively. A significantly increased risk was found for current smokers (RR = 3.9; p less than 0.05). However, the cumulative effect of smoking was not evident. No increased risk was found for obesity or for heavy physical work. Regarding causation of ON, this study confirmed the consistent association with excessive alcohol intake and suggested the immediate untoward effects of smoking. The role of heavy physical work as a form of mechanical stress was not correlated with ON.

Adult↗
PubMed1987

Basilar bifurcation aneurysm associated with bilateral internal carotid occlusion.

A case of subarachnoid hemorrhage from ruptured aneurysm of the basilar bifurcation associated with occlusions of both internal carotid arteries at the neck is presented. Each internal carotid artery mainly received collateral flow at the cavernous portion from the internal maxillary artery through anastomotic artery of the foramen rotundum. Posterior circulation also supplied collateral blood flow via the right posterior communicating artery. This case report suggests that hemodynamic stress may be regarded as an important factor in the formation or development of cerebral aneurysm.

Aged↗
PubMed1987

An epidemiologic study on the association between diet and breast cancer.

A case-control study of breast cancer was conducted in Hawaii with Japanese and Caucasian women between ages 45 and 74. Each case was matched to one hospital and one neighborhood control. In all, 183 sets of Japanese and 161 sets of Caucasian subjects were interviewed. No statistically significant differences were found between cases and controls in their mean intake of total fat, saturated fat, oleic acid, linoleic acid, animal protein, and cholesterol. Although there was a suggestion that cases consumed more saturated fat and oleic acid than neighborhood controls, the differences were not impressive. Consistent with other case-control studies, the present investigation did not provide strong support for the hypothesis that a high-fat diet is a risk factor for breast cancer. Further work is suggested to clarify the role of diet in determining breast cancer risk.

Aged↗
PubMed1987

Low-dose irradiation to head, neck, or chest during infancy as a possible cause of thyroid carcinoma in teen-agers: a matched case-control study.

A matched case-control study was performed to identify the etiologic factors for thyroid carcinoma in teen-agers. Twenty-seven cases and 69 controls were investigated to assess the significance of various maternal and subject factors. Irradiation during infancy was the only factor which showed a statistically significant association with the incidence of thyroid cancer in teen-agers (summary X2 = 8.040; d.f. = 1; P less than 0.005). The estimated dose ranged from 0.2 to 40 rads on the head, neck, or chest during infancy.

Female↗
PubMed1987

Risks for malignancies in patients with chronic thyroiditis: a long-term follow-up study.

As a typical autoimmune disease, chronic thyroiditis may impose unusual risks for malignancies. A long-term follow-up study of a large number of patients (4,531) with chronic thyroiditis at the Noguchi Hospital in Ooita Prefecture was conducted for 0-24 years, the objective being to assess risks for various sites of neoplasms by comparing the observed numbers of deaths with the expected numbers computed from the mortality rates in Japan. There was no increase in risk for overall malignancies (90 observed vs. 104.1 expected) or breast cancer (4 observed vs. 5.7 expected). The patients had an increased risk for myelo- and lympho-proliferative neoplasms (13 observed vs. 4.9 expected, P less than 0.01), as found in a few previous follow-up studies. A new and unexpected finding was that the patients showed decreased risk for cancers of digestive tract (24 observed vs. 44.3 expected, P less than 0.01). The reason for this decline could not be elucidated in this study, so that further epidemiological studies and animal experiments in this respect are needed.

Adolescent↗
PubMed1987

A cohort study on mortality of "yusho" patients: a preliminary report.

In 1968, a mass food poisoning (yusho) occurred in western Japan involving more than 1,850 people, the majority of whom were residents of Fukuoka and Nagasaki prefectures. The poisoning is now understood to have been caused by ingestion of a commercial brand of rice oil contaminated with polychlorinated derivatives of biphenyls, dibenzofurans, quaterphenyls, and some other related compounds. The number of deaths seen among 1,761 victims (887 males and 874 females) from the date of official registration as yusho up to the end of 1983 was compared with the expected number of deaths which was calculated on the basis of the national age, sex, and cause-specific death rates. Neither significantly increased nor significantly decreased mortality was seen among overall causes of death in males and females. A significant excess mortality was seen for malignant neoplasms at all sites in males but not in females. Neither significantly increased nor decreased mortality was seen for cancer of the esophagus, stomach, rectum and colon, pancreas, breast, and uterus. For cancer of the liver, however, a considerably increased mortality was seen in both males and females but the excess was statistically significant only in males. It was also notable that such increased mortality due to liver cancer was seen mainly among the patients living in Fukuoka prefecture but not at all among those in Nagasaki prefecture which approximate the yusho patients in Fukuoka prefecture in number. Deaths from chronic liver diseases and liver cirrhosis were also found to be increased in both sexes but the increase was not statistically significant.

Cohort Studies↗
PubMed1987

Augmentation of tumor immunity against syngeneic tumors in mice by beta-carotene.

The effect of beta-carotene on tumor immunity was examined with the use of a syngeneic murine tumor system. Oral administration of beta-carotene (120 micrograms/mouse/day) for 9 days from day 1 to the BALB/c mice inoculated sc with 10(7) syngeneic BALB/c Meth A fibrosarcoma cells (Meth A) led to a remarkable rejection against rechallenged Meth A implanted sc on day 10. The growth of Meth 1 fibrosarcoma (Meth 1), another syngeneic tumor of BALB/c origin, as a rechallenge tumor was unaffected by treatment with beta-carotene, thereby suggesting that beta-carotene may augment tumor rejection specific to tumor-specific antigens. Winn assay revealed that the suppressive effect on tumor growth of immune lymph node cells obtained from Meth A-inoculated beta-carotene-treated mice on day 12 was enhanced dose dependently. Primary effector cells responsible for the augmented rejection are Thy-1-positive, Lyt-1-negative, and Lyt-2-positive lymphocytes, presumably cytotoxic T-lymphocytes.

Animals↗
PubMed1987

[Growing aneurysm presenting with Weber's syndrome and obstructive hydrocephalus--a case report].

A case with two cerebral aneurysms, in which one at the origin of the left superior cerebellar artery (SCA) grew and presented with Weber's syndrome and obstructive hydrocephalus, is reported. The patient was a 69-year-old female, who had severe headache and vomited. On admission, neck stiffness was recognized. CT scan showed findings of subarachnoid hemorrhage. Angiograms demonstrated two saccular aneurysms at the right middle cerebral artery (MCA) bifurcation and at the origin of the left SCA. Craniotomy and neck clipping of the aneurysm at the right MCA was performed. After discharge, left oculomotor palsy appeared and gradually progressed. Severe headache and right hemiparesis suddenly occurred two years after the first attack. On the second admission, CT scan revealed high density on the brain surface and a well enhanced round lesion at the left ambient cistern. Left vertebral angiogram demonstrated increase in size of the aneurysm at the left SCA. The patient was discharged after conservative therapy. Drowsiness and urinary incontinence appeared, and she was admitted for the third time three years after the first admission. CT scan showed an enhancing mass lesion sized 25 X 30 mm beside the left midbrain and obstructive hydrocephalus. The aneurysm at the SCA no longer seen on the left vertebral angiogram. V-P shunt was performed. Both Weber's syndrome and obstructive hydrocephalus in this case indicate an aneurysmal natural history, in which aneurysm becomes gigantic and thrombosed spontaneously.

Aged↗
PubMed1986

The association of replacement estrogens with breast cancer.

This epidemiologic case-control study examined the relationship between replacement estrogen use and breast cancer risk in 2 population groups in Hawaii. No significant associations were observed when 161 Caucasian cases were compared with either their neighborhood controls (RR = 0.9; 95% Cl = 0.5-1.3) or their hospital controls (RR = 0.7; 95% Cl = 0.4 to 1.1) and when 183 Japanese cases were compared with either their neighborhood controls (RR = 1.1; 95% Cl = 0.7-1.6) or their hospital controls (RR = 1.0; 95% Cl = 0.6-1.4). The results indicate that the use of replacement estrogens cannot account for the large difference in breast cancer incidence between the 2 Hawaiian ethnic groups. However, further data analysis involving neighborhood controls was suggestive of a possible increase in breast cancer risk with estrogen use for certain sub-groups of women who are at high risk for the disease. These included estrogen users with a family history of breast cancer or a history of benign breast disease. These findings are in agreement with other studies which have used non-hospitalized controls. Because the numbers of cases in this study are not substantial, it is recommended that a large population-based case-control study be undertaken to clarify the relationship between breast cancer risk and replacement estrogen use, especially in sub-groups of women at high risk for the disease.

Aged↗