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K Mabuchi

Publications and source records attributed to K Mabuchi.

At least 55 records · Page 3Linked to original sources
PubMed1995

Incidence of benign gastrointestinal tumors among atomic bomb survivors.

Using the Hiroshima and Nagasaki tumor and tissue registries, benign tumors of the stomach, colon, and rectum were identified among members of the Life Span Study cohort of atomic bomb survivors. During the period 1958-1989, a total of 470 cases with histologically confirmed benign gastrointestinal tumors (163 stomach, 215 colon, and 92 rectum) were identified among approximately 80,000 Life Span Study members with known radiation doses, who were alive in 1958. Restricting the analysis to adenomatous tumors not detected at autopsy, a dose-response relation was observed for stomach tumors (excess relative risk at 1 sievert (ERR1Sv) = 0.53; 95% confidence interval (CI) -0.01 to 1.43). However, there was little evidence of a dose response for colon tumors (ERR1Sv = 0.14; 95% CI -0.20 to 0.76), and no evidence was present for rectal tumors (ERR1Sv = -0.25; 95% CI undetermined to 0.80). The excess relative risk (ERR) for benign tumors of the stomach is consistent with the excess found for stomach cancer. For cancer of the rectum, the dose response was not significant, but the point estimate of the excess relative risk was positive. The excess relative risk for benign colon tumors is less than that reported for colon cancer (ERR1Sv = 0.72). The authors observed a dramatic increase in colon tumors detected after 1985, suggesting that the relatively recent introduction of colonoscopy may be influencing these results.

Cohort Studies↗
PubMed1995

Physical characterization of calponin. A circular dichroism, analytical ultracentrifuge, and electron microscopy study.

Calponin is a thin filament-associated smooth muscle protein that has been suggested to play a role in the regulation of smooth muscle contraction. We have used circular dichroism spectroscopy, electron microscopy, and analytical ultracentrifugation to study the physical properties of recombinant chicken gizzard alpha-calponin. The alpha-helix content of alpha-calponin was estimated from its circular dichroism spectrum to be approximately 13%, alpha-Calponin melts with a single sharp transition at approximately 57 degrees C. Rotary shadowing electron micrographs of alpha-calponin reveal diverse shapes ranging from elongated rods to collapsed coils. The lengths of the rod-shaped structures are approximately 18 nm. Analytical ultracentrifugation studies found alpha-calponin to be homogeneous with a monomer molecular mass of 31.4 kDa, and a s20,w value of 2.34 S. These data could be used to model alpha-calponin as a prolate ellipsoid of revolution with an axial ratio of 6.16, a length of 16.2 nm, and a diameter of 2.6 nm. Taken together, our results indicate that calponin is a flexible, elongated molecule whose contour length is sufficient to span three actin subunits along the long pitch helix of an F-actin filament.

Animals↗
PubMed1995

Radiation studies.

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Government Agencies↗
PubMed1995

Prospective cohort study of risk factors for primary liver cancer in Hiroshima and Nagasaki, Japan.

We investigated risk factors for primary liver cancer among a cohort of 36,133 residents in Hiroshima and Nagasaki, Japan, originally established to examine the association between exposure to atomic bomb radiation and disease. A mail survey to study the late effects of atomic bomb radiation was conducted among the cohort between 1978 and 1981. During the subsequent follow-up period (average 8.61 years), 242 cases of primary liver cancer were identified through population-based tumor registries in the two cities. The relative risk (RR) of liver cancer was 2.23 [95% confidence interval (CI) = 1.53-3.23] for tobacco smokers compared with those who had never smoked. Alcohol use was slightly positively associated with the risk of liver cancer, and men who had quit drinking had an RR of 2.33 (95% CI = 1.34-4.07) compared with those who never drank. Among alcohol drinkers, an inverse relation between years of abstinence and the rate of liver cancer was found, possibly attributable to a confounding effect of preclinical disease. The use of female hormone preparations was modestly associated with the risk of liver cancer (RR = 1.29; 95% CI = 0.59-2.84). Other risk factors included a self-reported history of radiation therapy (RR = 1.79; 95% CI = 1.31-2.43).

Adult↗
PubMed1995

Basic study to develop the undulation pump for practical use: antithrombogenicity, hemolysis, and flow patterns inside the pump.

The undulation pump (formerly called the precessional displacement pump) is a continuous flow displacement-type blood pump that is being developed as an implantable total artificial heart. A new undulation pump was developed for chronic use and was examined with animal experiment and flow visualization studies. In the animal experiment using a left ventricular bypass in goats, severe hemolysis occurred. After driving for 12 h, thrombus formation inside the pump was found. In the flow visualization studies, the flow pattern showed that the flow inside the pump was a very complicated turbulent flow. Improvement of hemolysis and thrombus formation is important to realize implantable total artificial hearts using undulation pumps.

Animals↗
PubMed1995

New version of flow-transformed pulsatile total artificial heart with no electrical switching valve.

The flow-transformed pulsatile total artificial heart (FTPTAH) is a new pulsatile total artificial heart that consists of a single continuous flow rotary blood pump and blood flow switching valves. It can perfuse the pulmonary and the systemic circulation alternately with pulsatile flow. A new version of the FTPTAH, which consists of one undulation pump (UP), 4 jellyfish valves, and a compensatory chamber, has been proposed. The UP is a reversible continuous flow blood pump, and flow transformation is caused by switching the direction of the motor rotation so that no electrical flow switching valve is needed. A prototype model could perfuse alternately pulmonary and systemic circulation with 3.0 L/min in a mock circulation. Unoxygenated blood in the UP at the end of pulmonary circulation will be stored in the compensatory chamber by shifting a flexible membrane to the direction of the left atrium (LA); therefore, the blood is not sent to the systemic circulation.

Atrial Function↗
PubMed1995

Development of a new apparatus to observe microcirculation chronically in continuous flow blood pump research.

To observe microcirculation chronically is an important key to the successful evaluation of the continuous flow blood pump. In this study, we succeeded in developing a new apparatus by which microcirculation could be observed chronically without a microscope in a conscious animal. The apparatus utilizes a charge coupled device (CCD). A thin living tissue, such as mesentery, is put directly on a highly integrated CCD and is lit up through the tissue with a light-emitting diode (LED). The vascular nets in the tissue are projected onto the CCD like a contact photograph, which is then sent to a television screen and which can be used to analyze their motion and function. A 0.5-inch CCD having 250,000 pixels was used in this study. The cover glass of the CCD was removed, and a fiber optic plate was fixed onto the surface of the CCD for the tissue to be able to contact with the apparatus surface without clearance. The CCD as well as the LED were molded with epoxy resin for electrical insulation. The apparatus was 35 mm wide and 12 mm high with a micro stand for an LED, which can be easily implanted into an animal. The apparatus was implanted into a rabbit for 12 h. The configuration of arterioles and venules, tens of micrometers in diameter, and their motions in subcutaneous tissue could be observed.

Animals↗
PubMed1995

Anti-Human T-lymphotropic virus type-I antibodies in atomic-bomb survivors.

Adult T-cell leukemia (ATL), induced by human T- lymphotropic virus type-I (HTLV-I), is endemic in Nagasaki, Japan. To investigate the effects of atomic-bomb radiation on development of this specific type of leukemia, 6182 individuals in the Radiation Effects Research Foundation (RERF) Adult Health Study sample in Hiroshima and Nagasaki were examined for positive rate of HTLV-I antibody. Several lymphocyte parameters were also studied for 70 antibody- positive subjects in Nagasaki. The HTLV-I antibody-positive rate was higher in Nagasaki (6.36%) than in Hiroshima (0.79%) and significantly increased with increasing age, but no association was observed with radiation dose. Whether relationship existed between antibody titer levels and radiation dose among antibody-positive subjects was not The frequency of abnormal lymphocytes tended to be higher in antibody-positive subjects than in antibody-negative subjects, and higher in females than in males regardless of radiation dose. The lymphocyte count was lower in antibody-positive subjects than in antibody-negative subjects and lower in female than in male subjects. No evidence was found to suggest that atomic-bomb radiation plays an important role in HTLV-I infection.

Adult↗
PubMed1995

[Auditory disturbance induced by carbamazepine administration in a patient with secondary generalized seizure].

We report on an 18-year-old woman with secondary generalized seizure, who developed an auditory disturbance (flat a tone) after carbamazepine (CBZ) administration. She used to have brief episodes of conjugate deviation of the eyes to the right, head heaviness, teleopsia, and visual hallucination since 16 years of age. At the age of 18 years, she developed a tonic-clonic seizures during sleep, and was placed on CBZ 400 mg/day. Immediately after taking the medication, she developed auditory disturbance while she played the musical instruments: she felt as if she played the musical note almost a half tone lower. On admission, neurological examinations and magnetic resonance images of the brain were normal. Electroencephalogram at rest was normal. However, intravenous diphenhydramine injection induced spikes in the left temporo-occipital region, followed by diffuse spike and wave complex. Although the serum CBZ level was reduced to the therapeutic level by lowering CBZ administration from 200 to 150 mg/day, she continued to have the same auditory disturbance. When CBZ administration was discontinued, the symptoms also disappeared. It remains unknown whether such a subtle side effect of CBZ is a common thing, or it can be recognized only by persons who are well trained in music.

Adolescent↗
PubMed1995

Thyroid cancer after exposure to external radiation: a pooled analysis of seven studies.

The thyroid gland of children is especially vulnerable to the carcinogenic action of ionizing radiation. To provide insights into various modifying influences on risk, seven major studies with organ doses to individual subjects were evaluated. Five cohort studies (atomic bomb survivors, children treated for tinea capitis, two studies of children irradiated for enlarged tonsils, and infants irradiated for an enlarged thymus gland) and two case-control studies (patients with cervical cancer and childhood cancer) were studied. The combined studies include almost 120,000 people (approximately 58,000 exposed to a wide range of doses and 61,000 nonexposed subjects), nearly 700 thyroid cancers and 3,000,000 person years of follow-up. For persons exposed to radiation before age 15 years, linearity best described the dose response, even down to 0.10 Gy. At the highest doses (> 10 Gy), associated with cancer therapy, there appeared to be a decrease or leveling of risk. For childhood exposures, the pooled excess relative risk per Gy (ERR/Gy) was 7.7 (95% CI = 2.1, 28.7) and the excess absolute risk per 10(4) PY Gy (EAR/10(4) PY Gy) was 4.4 (95% CI = 1.9, 10.1). The attributable risk percent (AR%) at 1 Gy was 88%. However, these summary estimates were affected strongly by age at exposure even within this limited age range. The ERR was greater (P = 0.07) for females than males, but the findings from the individual studies were not consistent. The EAR was higher among women, reflecting their higher rate of naturally occurring thyroid cancer. The distribution of ERR over time followed neither a simple multiplicative nor an additive pattern in relation to background occurrence. Only two cases were seen within 5 years of exposure. The ERR began to decline about 30 years after exposure but was still elevated at 40 years. Risk also decreased significantly with increasing age at exposure, with little risk apparent after age 20 years. Based on limited data, there was a suggestion that spreading dose over time (from a few days to > 1 year) may lower risk, possibly due to the opportunity for cellular repair mechanisms to operate. The thyroid gland in children has one of the highest risk coefficients of any organ and is the only tissue with convincing evidence for risk about 1.10 Gy.

Adolescent↗
PubMed1994

The effect of additive hyaluronic acid on animal joints with experimentally reduced lubricating ability.

A series of in vitro experiments demonstrated a clear effect of additive hyaluronic acid (HA) on animal joints with experimentally reduced lubricating ability. Eleven canine hip joints were utilized and the experimental conditions tested were: i) intact joints, ii) after washing the joint surfaces, and iii) after adding 1% HA to them. The frictional coefficient of every joint increased after washing and subsequently decreased after adding HA. The mean values were 0.007 (SD 0.004) on the intact joints, 0.020 (SD 0.009) after washing, and 0.013 (SD 0.005) after the addition of HA. The differences between the three values of frictional coefficients were shown to be statistically significant (p < 0.01).

Animals↗
PubMed1994

Cancer incidence in Hiroshima and Nagasaki, Japan, 1958-1987.

The Hiroshima and Nagasaki tumour registries, which have been in operation since 1958, are among the few population-based cancer registries in Japan. This analysis evaluated cancer incidence in Hiroshima and Nagasaki between 1958 and 1987. The overall age-adjusted (World Population Standard) cancer incidence has increased from 217 to 301 per 100,000 among males, and from 176 to 197 per 100,000 among females during the first 30 years of cancer registration. The most recent rates are intermediate to rates in other countries. Despite a gradual decrease, gastric cancer remained the most common malignancy among males and females throughout the surveillance period, accounting for 24% of all cancers by the late 1980s. The rate of liver cancer has increased dramatically among males during the past 20 years, with a 2-fold increase in incidence in the past 10 years alone. The populations of Hiroshima and Nagasaki now have among the highest rates of liver cancer in the world. Breast cancer incidence in Hiroshima and Nagasaki, in contrast, is among the lowest in the world, although incidence rates have doubled since the 1960s. Other common malignancies include cancers of the lung, colon and rectum among males and cancers of the colon, cervix and lung among females.

Adolescent↗
PubMed1994

Agreement between death certificate and autopsy diagnoses among atomic bomb survivors.

Based on the Atomic Bomb Casualty Commission/Radiation Effects Research Foundation series of over 5,000 autopsies, we examined death certificate accuracy for 12 disease categories and assessed the effect of potential modifying factors on agreement and accuracy. The overall percentage agreement between death certificate and autopsy diagnoses was only 52.5%. Although neoplasms had the highest detection rate, almost 25% of cancers diagnosed at autopsy were nevertheless missed on death certificates. Confirmation and detection rates were above 70% for neoplasms and external causes of death only. Confirmation rates were between 50 and 70% for infectious diseases and heart and other vascular diseases. Detection rates reached a similar level for infectious, cerebrovascular, and digestive diseases. Specificity rates were above 90% for all except the cerebrovascular disease category. Overall agreement decreased with increasing age at death and was worse for deaths occurring outside of hospital. There was some suggestion that agreement improved over time, but no indication that radiation dose, sex, city of residence, or inclusion in a biennial clinical examination program influenced agreement. Since the inaccuracy of death certificate diagnoses can have major implications for health research and planning, it is important to be aware that their accuracy is low and that it can vary widely depending on cause, age and place of death.

Aged↗