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S Akiba

Publications and source records attributed to S Akiba.

124 records · Page 7Linked to original sources
PubMed1989

Lung cancer risk comparison among male smokers between the "six-prefecture cohort" in Japan and the British physicians' cohort.

We estimated the effective duration of cigarette smoking using the data of lung cancer mortality among male smokers of a large-scale cohort study in Japan and evaluated its role in the lung cancer risk difference between male smokers of the Japanese cohort and the British physicians' cohort. By selecting male cohort members who answered that they had started smoking at ages 18-22 (average = 20.3), the subjects of our analysis, which numbered 49,013, were made relatively homogeneous in terms of age at which smoking was started. Assuming lung cancer mortality to be proportional to the 4.5th power of the effective duration of cigarette smoking, i.e., (age-theta)4.5, as was proposed on the basis of the British cohort study by Doll and Peto, the parameter theta was estimated to be 29.4 for male smokers aged 40-64 in 1966; therefore, the estimated duration of cigarette smoking was, on average, 9.1 years (95% confidence interval = 5.8-11.6) shorter than that calculated from the reported age at which smoking was started. Our findings suggested that the low lung cancer mortality relative to daily cigarette consumption in Japan resulted from the shorter duration of cigarette smoking in the Japanese cohort, possibly due to the severe shortage of cigarettes during and shortly after World War II. Once the effective duration of cigarette smoking was adjusted, lung cancer mortality in the range of 5-34 cigarettes per day was fairly comparable to that observed among the cohort of male British physicians.

Adult↗
PubMed1989

Smoking and lung cancer mortality in Japanese men: estimates for dose and duration of cigarette smoking based on the Japan vital statistics data.

For the purpose of understanding human carcinogenesis and making a quantitative prediction of lung cancer mortality in a general population of Japanese males, we evaluated a statistical model which assumes lung cancer mortality to be proportional to the 4.5th power of the effective duration of cigarette smoking among smokers and to the 4th power of age among nonsmokers, using Japan Vital Statistics data. For the male birth cohorts aged 30-69 in 1965 in the age range of 40-79, studied by quinquennial calendar time intervals from 1955 to 1985, it was found that, (i) for nonsmokers, the estimated lung cancer mortality rate was comparable to the rates reported in the US or Britain, assigning 20 to 25% proportions of nonsmokers, (ii) for smokers, the estimated duration of smoking was shorter than would be expected from the age when smoking was started according to various epidemiological surveys, and (iii) the estimated average numbers of cigarettes smoked per day by smokers were similar to those obtained by epidemiological studies, when these were estimated by incorporating a part of Doll and Peto's dose-response relationship. Also discussed is the possibility of assessing lung cancer mortality risk for Japanese male smokers by means of the statistical model, alpha x (cigarettes smoked per day + beta) x (age - (age started smoking) - gamma)4.5.

Adult↗
PubMed1989

[Inhibitory effect of various traditional Chinese medicines on rabbit platelet phospholipase A2 in vitro and suppressive effect of tôki-syakuyaku-san on increased aggregability in hypercholesterolemic rabbit ex vivo].

The inhibitory mechanism of 6 traditional Chinese medicines on rabbit platelet aggregation in vitro, and the suppressive effect of oral administration of Tôki-syakuyakusan on hyper-aggregability of the platelet from rabbit fed high cholesterol diet for 2 months, were investigated. Collagen-induced aggregation was inhibited by Keisi-bukuryôgan, Kami-syôyô-san, Dai-saiko-tô, Tôki-syakuyaku-san, Hatimi-ziô-gan and Syô-saiko-tô in their lower concentrations than those inhibiting arachidonic acid- and thrombin-induced aggregation. These traditional Chinese medicines inhibited the release of [3H]arachidonic acid from membrane phospholipids by phospholipase A2, in [3H]arachidonic acid-labelled platelets under stimulation with collagen and thrombin in the concentration ranges that inhibited each aggregation. In their higher concentrations to inhibit arachidonic acid-induced aggregation, they suppressed the conversion of arachidonic acid to thromboxane A2 by about 50%. However, they had no effect on diacylglycerol formation induced by thrombin. The oral administration of Tôki-syakuyaku-san depressed the increased aggregability of platelets from rabbit fed high cholesterol diet by 20-40% at the period of 1-2 months of feeding, without affecting plasma and platelet cholesterol level. These results indicate that the traditional Chinese medicines used here have an inhibitory effect on platelet phospholipase A2 activation, rather than on cyclooxygenase, and therefore inhibit platelet activation in vitro and ex vivo.

Animals↗
PubMed1989

Age and dose related alteration of in vitro mixed lymphocyte culture response of blood lymphocytes from A-bomb survivors.

The responsiveness of peripheral blood lymphocytes to allogenic antigens in mixed lymphocyte culture (MLC) was measured in 139 atomic-bomb survivors. The study revealed a significant decrease in MLC response with increasing dose of previous radiation exposure. This decline was marked in the survivors who were older than 15 at the time of the bomb (ATB). The results suggest a possible relationship between the recovery of T-cell-related function and the thymic function which processes mature T cells for the immune system. Thus it may be that in the advanced age ATB group, the thymus function had started to involute, allowing less recovery of T-cell function compared to young survivors who had adequate processing T-cell activity.

Aged↗
PubMed1989

[The development of health risk appraisal for Japanese as a new health educational tool].

Health risk appraisal (HRA) is a new health educational tool widely-used in the United States, which informs clients about how their health habits and lifestyles affect their probability of dying from potentially preventable causes and helps to motivate them to reduce their personal health risks. It personalizes mortality statistics and epidemiologic data by combining these data with a person's risk factors. We have got started the development of HRA for Japanese with reference to a new version of HRA named "Healthier People" revised by the Carter Center of Emory University and the Centers for Disease Control in the United States.

Health Education↗
PubMed1988

Vinblastine inhibits platelet aggregation by a microtubule-independent mechanism, probably by its perturbing action on the plasma membrane.

Inhibitory mechanism of vinblastine on platelet activation was examined with respect to its effect on disassembly of the microtubule system. Vinblastine at 10 microM concentration caused washed platelets to become sphere with disorganized microtubule system, but did not affect aggregation induced by collagen, arachidonic acid or thrombin. Collagen-induced aggregation was inhibited by 50-100 microM of vinblastine and much higher concentration was required to inhibit arachidonic acid- and thrombin-induced aggregation. When the vinblastine (100 microM)-treated platelets were washed with albumin medium, the impaired aggregability was well recovered in response to collagen. In this case, however, both the vinblastine-induced sphered shape and disappeared microtubule system were not recovered to the normal states. Within the concentration ranges that inhibited collagen-induced aggregation, vinblastine also suppressed reversibly Ca2+ influx and arachidonic acid liberation from membrane phospholipids by phospholipase A2. Conversion of added arachidonic acid to thromboxane A2 was not inhibited even by such concentration. These results suggest that vinblastine interacts non-specifically with the cell membrane to cause reversible inhibition of arachidonic acid liberation by phospholipase A2 and Ca2+ influx and thereby aggregation through physical perturbation of membrane lipid bilayer, independent of the activity to disassemble platelet microtubule system.

Adenosine Triphosphate↗
PubMed1988

Effect of phorbol 12-myristate 13-acetate on collagen-induced signal transduction in rabbit platelet.

Investigations were made on the inhibitory effect of phorbol 12-myristate 13-acetate (PMA), a powerful activator on protein kinase C, on collagen-induced signal transduction in washed rabbit platelets. Upon activation of the platelets with a low-dose of collagen (5 micrograms/ml), which was suppressed by 10 microM indomethacin, pretreatment of the platelets with 2 nM PMA caused prolongation of lag phase (2 min) before the onsets of the aggregation and ATP secretion as compared with PMA-untreated platelets (30 sec). Under this condition, appearance of the cell responses including the phosphatidic acid formation, thromboxane (Tx) generation and Ca2+-influx was similarly retarded for 2-3 min, whereas arachidonic acid liberation from the membrane phospholipids was not significantly affected by the PMA pretreatment. After such lag phase, every response appeared rapidly and reached almost the control value (without PMA). Upon activation of the same platelets with a high-dose of collagen (50 micrograms/ml), which was only half suppressible by indomethacin, PMA in the presence of indomethacin almost completely suppressed the phosphatidic acid formation as well as the aggregation and ATP secretion. Thus, our results suggest that collagen-platelet interaction may elicit direct activation of phospholipase A2 and C, and that the latter enzyme activation may be regulated by a negative effect of protein kinase C. However, the phospholipase A2 activation may be regulated by a mechanism independent of such effect. In PMA-pretreated platelets in response to a low-dose of collagen, the prolonged lag phase for aggregation appears to be due to impaired conversion of liberated arachidonic acid to TxA2.

Adenosine Triphosphate↗
PubMed1986

Passive smoking and lung cancer among Japanese women.

A case-control study conducted in Hiroshima and Nagasaki, Japan, revealed a 50% increased risk of lung cancer among nonsmoking women whose husbands smoked. The risks tended to increase with amount smoked by the husband, being highest among women who worked outside the home and whose husbands were heavy smokers, and to decrease with cessation of exposure. The findings provide incentive for further evaluation of the relationship between passive smoking and cancer among nonsmokers.

Female↗
PubMed1982

Body burdens of 137Cs in a selected group of male adult residents in Chiba, Japan from 1967 to 1976.

Body burdens of 137Cs for Japanese males have shown a decreasing tendency from about 3.6 nCi in 1967 to 1.0 nCi in 1976 with the exception of a small rise for the period from 1970 to 1971. The reduction rate of the dose differed considerably before and after 1969, with an estimated half-time of 1.5 yr for the period before 1969 and 7.1 yr after 1969. The accumulated internal radiation dose was 7.6 mrad from 1964 to 1976. About a quarter of the dose, 2.3 mrad, was estimated to result from fairly recent nuclear explosions. The dose commitment by the year 2000 is estimated to be 8.8 mrad, which is smaller than the annual dose due to 40K in an averaged Japanese male, 19.2 mrad.

Adult↗
PubMed1981

A survey of rotavirus infection in the topics.

The age distribution of rotavirus antibody in the serum of inhabitants of Laos and Indonesia was studied by the neutralization test using antigenically related calf rotavirus (NCDV) as a substitute for non-cultivable human rotavirus. The results revealed that both the rate of antibody-positives and the modal titers of antibody distribution by each age group in these countries were higher than those in respective are groups of Japanese, which suggest higher endemicity of rotavirus infection in these countries. A survey of rotavirus in diarrheic patients' stools by enzyme-linked immunosorbent assay indicated that the virus infection occurred most frequently among infants between 4 and 12 months of age.

Adolescent↗
PubMedDate not supplied

Angiogenesis in esophageal squamous cell carcinoma.

We retrospectively analyzed the prognostic significance of angiogenesis and the relationships between tumor angiogenesis and clinopathological variables in a series of 127 patients with primary esophageal squamous cell carcinoma which were curatively resected. Vessels were stained with anti-factor VIII polyclonal antibody and areas with the highest number of microvessels were counted in a x400 field. Microvessel counts were significantly correlated with pN category, pM category, venous invasion and recurrence (p=0.002, p=0.040, p=0.016 and p=0.0013, respectively). The proportion of patients with recurrence increased in proportion to the number of microvessels. multivariate analysis using Cox's proportional hazard modelling showed angiogenesis assessed by microvessel count affected the poorer prognosis of patients with esophageal squamous cell carcinoma (hazard ratio, 1.03; 95%CI, 1.00-1.07), although it was not a significant independent prognostic factor (P=0.088). This study suggest that angiogenesis assessed by microvessel count is a marker for relapse and prognosis in patients with esophageal squamous cell carcinoma.

Aged↗