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Biomedical subjects

H Sakurai

Publications and source records attributed to H Sakurai.

At least 433 records · Page 24Linked to original sources
PubMed1992

The development of a self-efficacy scale for exercise behavior.

The purpose of the study was to develop a self-efficacy scale for exercise behavior. The draft items of self-efficacy scale were chosen from the previous studies, and were modified to reflect the socioeconomic differences in the target population. Ratings were made on a 3-point Likert-type scale. The self-efficacy scale was administered to 647 employees in a Japanese manufacturing company in 1990. They were also asked to identify their exercise behavior as one of exercising more than once a week, or not exercising. Two factors were extracted by principal component factor analysis with varimax rotation, and those two factors had eigenvalue of greater than 1.0. They were named "high priority" and "independent factor". Cronbach's alpha coefficients were 0.90 and 0.84 for high priority and independent factor, respectively. The test-retest correlations for the high priority and the independent factor were 0.83 and 0.74, respectively. Both factor scores and scale scores were significantly higher in employees who habitually exercised compared with those who did not exercise. A significantly higher percentage of employees with high self-efficacy scores exercised regularly than those with lower self-efficacy scores. This study provided evidence of reliability and validity of the newly developed self-efficacy scale for exercise behavior in Japan.

Adult↗
PubMed1992

Relationship between autoepitope and DNA-binding site on a histone H1 molecule.

Autoepitope and DNA-binding domain on a histone H1 molecule were compared using truncated histone H1 peptides as antigens. At least two epitopes (epitope A, N-terminal side; epitope B, C-terminal side) were found both of which were composed of approximately 20 amino acids. IgM from all 17 anti-histone H1-positive SLE sera reacted with epitope A. IgG from 12 sera reacted with epitope A and IgG from 4 sera reacted with epitope B. In one case, no IgG anti-histone H1 reactivities were found while IgM from the same patient reacted with epitope A. Epitope A had the ability to bind DNA. The reactivities against histone H1 of affinity-purified antiepitope A autoantibodies were inhibited by DNA. These data suggest that some anti-histone H1 antibodies are directed against a histone H1 DNA-binding site, raising the possibility that an idiotype/anti-idiotype network, at least in part, is involved in the generation of anti-histone H1 autoantibodies.

Autoimmunity↗
PubMed1992

Generation of active oxygen species in blood platelets--spin trapping analysis.

Generation of active oxygen species by bovine blood platelets was examined by the electron spin resonance (ESR) spin trapping technique with 5,5-dimethyl-1-pyroline-1-oxide (DMPO). The hydroxyl spin-trapped adduct 5,5-dimethyl-2-hydroxyl-1-pyrolidinyloxy (DMPO-OH) was formed in the presence of platelets, indicating the generation of hydroxyl radicals (.OH) by the platelets. Generation of .OH was observed even with platelets in the resting state, but was markedly enhanced when the platelets were activated with stimulants. Stronger stimulants such as the calcium ionophore ionomycin, induced greater radical generation than the weaker stimulant ADP. When the platelets were stimulated by thrombin, generation of .OH was greatest after 1.5 min, and depended on the dose of the stimulant. It was inhibited by inhibitors of platelet activation such as forskolin and phenolic antioxidants.

Adenosine Diphosphate↗
PubMed1992

Symptomatic rib lesions as the primary presentation of sarcoidosis. Report of two cases and review of literature.

Skeletal involvement in sarcoidosis is considered a manifestation of chronic disease. Rib lesions, while rarely reported, have been usually asymptomatic and often associated with vertebral sarcoidosis. Here, we report two patients with symptomatic rib lesions in sarcoidosis. Both patients were black males. In both cases, chest X-rays lacked characteristics of pulmonary sarcoidosis. A definite diagnosis was made on rib biopsies and confirmed by the positive Kveim test. One case was particularly interesting in that low back pain preceded the right hilar adenopathy for many years. This suggests that sarcoidosis involving the bone may occur at early stage of disease, and that low back pain in young male may be the first presentation of sarcoidosis. A literature review of osseous involvement in sarcoidosis reveals that skeletal lesions in sarcoidosis may preferentially manifest in the axial skeleton in some individuals.

Adult↗
PubMed1992

[Determination of nicarbazin in imported chicken].

The confirmation and quantitative analysis of nicarbazin (NCZ) in imported chickens were made by high performance liquid chromatography equipped with a photodiode array detector. The results showed that 1 out of 7 chicken samples contained over 30 ng/g of NCZ. The concentrations of NCZ varied from 10 to 120 ng/g according to the parts of the NCZ positive chicken samples.

Animals↗
PubMed1992

[Migration test of lead and cadmium from plastic wares in contact with food].

Release of lead and cadmium from plastic tableware was examined. Samples were treated with 2 ml of 4% acetic acid or 0.1N HCl per cm2 of the surface area at 60 degrees C or 95 degrees C for 30 min. No migration of lead and cadmium from samples containing up to 391 ppm lead or 6863 ppm cadmium was observed.

Cadmium↗
PubMed1992

[Determination of volatile substances and leachable components in polystyrene food contact wares].

Material and migration tests of food-contact plastic wares made of polystyrene were carried out. The average concentration of volatile substances (sum of toluene, ethylbenzene, isopropylbenzene, n -propylbenzene, and styrene) in materials was 861 +/- 692 ppm. Styrene was observed in 95% of 19 samples. alpha-Methylstyrene, which is one of the material compounds of polystyrene, was detected in one sample. Release of volatile substances into n-heptane was not observed at the detection limits of 0.1 ppm.

Cooking and Eating Utensils↗
PubMed1992

A binding profile of manganese to the nucleus of rat liver cells, and manganese-induced aberrations in thyroid hormone content and RNA synthesis in the nucleus.

Manganese (Mn) is accumulated in the nuclear and mitochondrial fractions when excess Mn is administered. However, little is known with respect to the behaviors of Mn in nuclei. In the present study, rats were given excess Mn and the nuclei were purified from liver cells by differential and sucrose gradient centrifugations. Being subjected to equilibrium dialysis with a radioactive 54Mn, the binding capacity of Mn in nuclei from the control rat was five-fold higher than BSA, which was used as a reference protein; and the capacity of 54Mn-binding rose in the nuclei from the Mn-treated animals in comparison with those from the control. On the analyses of nuclear materials with partial solubilization, sepharose column chromatography and HPLC, there were two major fractions which associated with a lot of Mn; one fraction was of large molecules of DNA, and the other fraction seemed to be peptides with small molecular weights. Therefore, Mn may open up a superhelical structure of DNA to provide more negatively charged phosphate moiety as a binding-site for a positively charged Mn. The results also disclosed a possible aberration in biological functions due to excess Mn in nuclei; the apparent association constant of triiodothyronine, a physiologically active thyroid hormone, to the nucleus was reduced by 75% and the uptake of 14C-labelled orotic acid to a newly synthesized RNA in the liver was severely inhibited.

Animals↗
PubMed1992

[Studies on a serum factor inhibiting lactate dehydrogenase (LDH) activity in a patient's serum].

We found extremely low activity of serum lactate dehydrogenase (LDH, EC. 1.1.1.27) in a 70-year-old female patient. The decrease of LDH activity was observed when the normal serum was incubated with the patient's serum. Inhibition rate of LDH activity by the patient's serum was higher at 4 degrees C than at 37 degrees C. The patient's serum inhibited both subunits of LDH, and inhibited more strongly the M-subunit than the H-subunit LDH isoenzymes. IgG (lambda type) in the patient's serum was found to be responsible for the inhibition of LDH activity. The mechanism why IgG inhibiting LDH activity developed in the patient's serum remain undetermined.

Aged↗
PubMed1992

[Relationship of smoking to absenteeism due to illness and injury in male workers].

The relationship between smoking and absenteeism due to illness and injury was studied in 21,924 male workers employed in the chemical fiber industry in Japan. Smokers had a significantly higher incidence of absence than non-smokers. The proportion of cases of absence in smokers was 30% higher and the number of days of absence was 28% greater than in non-smokers. Ex-smokers also had a significantly higher incidence of absence than non-smokers. In ex-smokers the proportion of cases of absence was 22% higher and the number of days of absence was 68% greater than in non-smokers. Although there was no significant difference between smokers and non-smokers in the number of days of absence attributed to cardiovascular or respiratory diseases, smokers were absent for about twice as many days as non-smokers for diseases of the digestive system. For ex-smokers the number of days of absence was 4.3 times higher for cardiovascular diseases, 1.5 times higher for respiratory diseases, and 2.9 times higher for digestive system diseases than in non-smokers. After correction for age, type of work, Body Mass Index, exercise, and drinking by multiple logistic analysis significantly elevated relative risks for absence persisted both in smokers and ex-smokers vs. non-smokers at 1.4 and 1.3, respectively. Significant dose-response relationships between incidence of absence and the number of cigarettes smoked per day were observed in respiratory disease, diseases of the digestive system and all disease causes. A significant dose-response relationship between incidence of absence and smoking index was also observed for diseases of the digestive system. These findings clearly indicate that smoking by workers was associated with absence due to illness and injury, and suggest that smoking was a factor contributing to an increase in absenteeism due to illness and injury in workers.

Absenteeism↗
PubMed1992

Acute renal injury by tetraethyl orthosilicate in mice: ultrastructure, histochemistry and X-ray microanalysis.

Tetraethyl orthosilicate (Si(OC2H5)4, or TEOS) is a silicon-containing compound which has widespread industrial applications and which has been documented as biohazardous. The histopathological features and mechanism of TEOS toxicity in the kidney of ICR mice were investigated in a light and electron microscopy study, which included energy dispersive X-ray microanalysis. TEOS was given to mice as intraperitoneal injection of approximately 1,670 mg/kg body weight in experiments based on a 24 h time-scale. Tissues were examined after sampling either immediately on death if this occurred within 24 h or, in the case of surviving animals, after sacrifice at 24 h. Renal injury was considered to be the most probable cause of death, on the basis of the following main findings: 1) acute tubular necrosis (glomerular lesions were absent); 2) a dense deposit of silicon over the microvilli of dead tubular epithelial cells; 3) an abundant aggregation of hydroxyapatite crystals containing calcium in the cytoplasm and mitochondria of the dead tubular epithelial cells; and 4) abundant myelinosomes and some hydroxyapatite crystals in the cytoplasm of viable proximal convoluted tubule epithelial cells. It was speculated that silicon compounds may bind to the plasma membranes of the proximal convoluted tubule epithelial cell microvilli and damage or interfere with membrane calcium channels. The resulting calcium ion imbalance may play a role in the subsequent progression of acute tubular necrosis by TEOS.

Animals↗
PubMed1991

Developmentally and regionally regulated alterations of octamer- and GC-box-binding activities during the postnatal development of mouse cerebellum.

Gel-mobility analyses using a DNA probe containing the SV40 enhancer-promoter revealed that the DNA-binding activities of cerebellar extracts changed drastically during the postnatal development of mouse brain. Three major DNA-protein complexes formed on the 72-bp enhancer (complexes E-I, E-II and E-III) were detected in the extracts prepared from the 2- and 10-day-old mouse cerebellum, but two of them (complexes E-II and E-III) were not detected in 3- and 7-week-old mice. In contrast, the formation of the complexes E-II and E-III, but not E-I, was observed in the cerebral cortex extracts throughout postnatal development until at least 7 weeks after birth. The addition of the octamer motif as a competitor abolished the formation of these three complexes. On the other hand, the formation of DNA-protein complexes on the 21-bp promoter by the cerebellar extracts increased after birth, while this increase in the formation of the complexes was not detected in the cerebral cortex extracts. This complex formation was found to be dependent upon the GC-box and to be stimulated by the addition of Zn2+, indicating that the protein binding to the 21-bp promoter may contain intramolecular zinc fingers. Thus, the expression of the octamer- and the GC-box-binding proteins are developmentally and regionally controlled in the cerebellum during the postnatal development of the mouse brain.

Animals↗
PubMed1991

Coordination structure and chemical reactivity of hemoprotein-butyl peroxide complex.

ESR and optical spectra ascribed to be the hemoprotein-butylperoxide complex were detected for the frozen aqueous solution containing whale met-Mb and t- or n-butylhydroperoxide at pH 10. The observed ESR and optical parameters of the complex were characteristic to those of six coordinate ferric low-spin complexes, having the butylperoxide anion at the axial position of heme. pH dependent ESR measurements demonstrated the formation of the complex in the biological pH regions (7.0). Time dependent ESR and optical measurements indicated that the complex may be one of the intermediate species in the processes of heme degradation reaction induced by butylperoxide.

Animals↗
PubMed1991

Effect of lead on cardiac parasympathetic function.

A cross-sectional survey was performed on 172 male, lead exposed workers to clarify the effects of lead on the cardiac autonomic nervous system expressed as the decrease of R-R interval variation on an electrocardiogram and to obviate the dose-effect relationship between blood-lead level (Pb-B) and the degree of the decrease. For 132 workers who were exposed to lead for more than one year and whose Pb-B levels were relatively stable (Pb-B variation less than 20 micrograms/dl during recent one year), a significant dose-related decrease of R-R interval variation during deep breathing was observed. Age-adjusted R-R interval variation during deep breathing in those whose Pb-B were 30 micrograms/dl or above was significantly decreased compared with those whose Pb-B levels were 20 micrograms/dl or below. This decrease was observed more clearly in younger workers. These results suggest that an effect on autonomic nervous system expressed as decrease of R-R interval variation during deep breathing might be one of the earliest effects of lead exposure.

Adolescent↗
PubMed1991

Gonadotrope responsiveness in orchidectomized sheep: I. Effect of continuous infusion of estradiol.

Gonadotrope function during continuous infusion of estradiol (E2) was evaluated in orchidectomized sheep (wethers). Serum concentrations of LH were reduced (p less than 0.05) within 3 h of introduction of E2 and remained depressed for the period of E2 delivery (48 h). Gonadotrope responsiveness (change in LH secretion induced by a 500-ng GnRH challenge, i.v.) was assessed 0, 3, 6, 12, 24, or 48 h after initiation of E2 infusion. Gonadotrope responsiveness was augmented (p less than 0.05) 12, 24, and 48 h after first introduction of E2. In a companion study, anterior pituitary tissue was collected 0, 3, 6, 12, 24, or 48 h after the beginning of E2 infusion. Tissue concentration of GnRH receptor was increased 3-fold within 12 h of first introduction of E2. Tissue stores of LH were also increased (p less than 0.05) during E2 infusion. Passive immunization against GnRH increased (p less than 0.05) tissue stores of LH, but had no effect on GnRH receptor concentration. Passive immunization against GnRH and concurrent infusion of E2 increased (p less than 0.05) both tissue stores of LH and tissue concentrations of GnRH receptor. The acute suppression of LH secretion induced by infusion of E2 was not affected by concurrent episodic administration of GnRH (200 ng/hourly pulse). However, serum concentrations of LH were restored to pretreatment levels within 12 h of initiation of E2 infusion and episodic delivery of GnRH. These data indicate that E2 acts in wethers to suppress gonadotropin secretion while simultaneously increasing GnRH receptor concentration, tissue stores of LH, and gonadotrope responsiveness.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

[Effects of ascorbic acid on the free radical formations of isoniazid and its metabolites].

By the use of electron spin resonance (ESR) spectroscopy and of spin-trapping technique, the effects of ascorbic acid on the formation of the free radical intermediates due to isoniazid (INAH) and its metabolites were investigated with a microsomal system. When alpha-(4-pyridyl 1-oxide)-N-tert butylnitrone (4-POBN) was used as a spin trapping agent, the ESR signal due to hydrazine (Hy) was formed to be most intensive among others. Therefore, it was presumed that Hy is a potent intermediate to cause an INAH-induced hepatic injury. In the presence of ascorbic acid (AA), the free radical formation of Hy, INAH and acetyl hydrazine was significantly inhibited, suggesting that AA may affect the INAH-hepatitis. By the addition of inhibitors of cytochrome P-450 like metyrapone and CO, the generation of the radical from Hy decreased, confirming that the radical is formed by the cytochrome P-450 dependent microsome systems. The 4-POBN-trapped radical species generated from Hy was presumed to be the hydrazyl radical by the results of mass spectrometry.

Animals↗