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Biomedical subjects

T Sakurai

Publications and source records attributed to T Sakurai.

At least 523 records · Page 29Linked to original sources
PubMed1991

Is focal chronic autoimmune thyroiditis an age-related disease? Differences in incidence and severity between Japanese and British.

The incidence of chronic lymphocytic thyroiditis in autopsy material from Japanese and British subjects was evaluated. Lymphocytic infiltration in representative thyroid sections from 1826 Japanese cases collected from four different institutions was analysed. The overall incidence of lymphocytic infiltration was significantly higher in females (22.2 per cent) than in males (13.9 per cent). In females, the incidence reached 23.2 per cent in the fourth decade and showed no increase with age thereafter. The overall incidence of lymphocytic infiltration in thyroid sections from 810 British cases was 42.5 per cent in females and 19.4 per cent in males; an increase in the incidence of thyroiditis from the sixth decade onwards was noted in British females, the figure reaching 50.0 per cent in those aged over 70 years. These findings suggest possible racial differences in susceptibility to chronic thyroiditis. The disorder is not necessarily related to age, increasing severity of disease with age being found only in British females.

Adult↗
PubMed1991

Hemodynamic assessment of chronic venous insufficiency.

To study the pathogenesis of chronic venous insufficiency (CVI), photoplethysmography and strain-gauge plethysmography were simultaneously performed in 84 patients. Of the 128 limbs studied, 24 were normal, 64 had primary varicose veins and 40 had post-thrombotic syndrome. Venography was also performed in all patients. The results of this study indicate that reflux in the superficial veins is the main pathophysiology involved in the development of CVI, though incompetence of the perforators and deep veins plays some role. In post-thrombotic syndrome, however, CVI is mainly a sequel of deep venous incompetence, the condition being complicated by incompetent perforators and superficial venous reflux.

Chronic Disease↗
PubMed1991

Simulated weightlessness and bone metabolism: evidence for direct gravitational effect and its related insulin action.

The effect of simulated weightlessness on bone metabolism was investigated in skeletal unloading for 4 days. Skeletal unloading was designed using the model of hind-limb hang in rats. In hypokinetic state, rats were fed while the right hind limb was weighed down and the left hind limb was unloaded (a state of weightlessness). Bone metabolism in normal rats did not vary significantly in the femoral diaphysis in right and left hind limb. Alkaline phosphatase activity and DNA content in the femoral diaphysis were not significantly altered by hypokinetic state without skeletal unloading, while the unloading caused an appreciable decrease in the enzyme activity and DNA content. However, femoral-diaphyseal zinc content and glucose consumption was significantly decreased by hypokinetic state with and without skeletal unloading. When femoral-diaphyseal tissues were cultured in the presence of insulin (10 nM), the hormone produced a significant increase of alkaline phosphatase activity and decrease of glucose consumption in the femoral-diaphyseal tissues obtained from normal and hypokinetic rats. This hormonal effect was not seen in bone tissues from hypokinetic rats with skeletal unloading. These results suggest that skeletal unloading-induced disorder of bone metabolism is directly related to gravitational effect and that gravitational stimulation may be involved in insulin action.

Alkaline Phosphatase↗
PubMed1991

Determination of the native subunit pattern of gizzard tropomyosin using antibodies specific to each subunit.

The gizzard tropomyosin molecule is composed of two subunits at 1:1 molar ratio. Possible composites of the tropomyosin molecule are two kinds of homodimer (one for each subunit), a heterodimer of two subunits, or a mixture of heterodimer and homodimer(s). We tried to evaluate the native subunit composition of gizzard tropomyosin by cross-linking experiments and immunological methods using specific antibodies to each subunit. For the cross-linking experiment we used dimethyl suberimidate, an amino group-specific cross-linker, in the presence of dithiothreitol to avoid artificial oxidative intersubunit cross-linking. When gizzard tropomyosin was cross-linked, it generated several products which might correspond to dimers formed by intersubunit cross-linkage. When the reaction was carried out for a long time, non-cross-linked subunits completely disappeared and two or three major cross-linked products arose. All of these cross-linked products were recognized by both of the specific antibodies to each subunit. These results indicated that the predominant part, if not all, of gizzard tropomyosin is present as heterodimer.

Animals↗
PubMed1991

1H-NMR studies of urine in propionic acidemia and methylmalonic acidemia.

The present study deals with the usefulness of 1H-NMR spectroscopy in the chemical diagnosis of propionic acidemia and methylmalonic acidemia. A Varian VXR-500 spectrometer was used. 1H-NMR spectra of urine from a patient with propionic acidemia show peaks of 3-hydroxy-n-valerate, methylcitrate, propionyl glycine, 3-hydroxy-n-butyrate, lactate, 3-hydroxypropionate, tiglylglycine and hippurate. The assignment was made possible by the use of 2D COSY. The spectra from a patient with methylmalonic acidemia show methylmalonate and glycine. 1H-NMR spectroscopy has the advantages of requiring a short time for analysis, relatively small amounts of urine and no preliminary extraction.

Amino Acid Metabolism, Inborn Errors↗
PubMed1991

Inhibition of experimental pulmonary metastasis of Lewis lung carcinoma by orally administered beta-glucan in mice.

The inhibitory effect on experimental pulmonary metastasis of Lewis lung carcinoma (3LL) of SSG, a (1----3)-beta-D-glucan obtained from the fungus Sclerotinia sclerotiorum IFO 9395, administered orally was examined in mice. Oral administration of SSG for 10 consecutive days just after the intravenous implantation of tumor cells significantly inhibited the experimental pulmonary metastasis of 3LL at a dose of 2000 micrograms. However, SSG administered orally involving other timings was less effective. In comparison with oral administration, SSG was effective when administered intraperitoneally for 10 consecutive days at a dose of 200 micrograms. These results suggest that SSG given by both parenteral and nonparenteral routes is effective in the inhibition of experimental pulmonary metastasis of tumors.

Animals↗
PubMed1991

Effect of intraperitoneally administered beta-1,3-glucan, SSG, obtained from Sclerotinia sclerotiorum IFO 9395 on the functions of murine alveolar macrophages.

The effect of intraperitoneally (i.p.) administered SSG, a beta-1,3-glucan obtained from the culture filtrate of the fungus Sclerotinia sclerotiorum IFO 9395, on the functions of alveolar macrophages (AM) in CDF1 mice was examined. SSG administered i.p. increased the number of AM and enhanced several functions of murine AM (lysosomal enzyme activity, phagocytic activity, candidacidal activity, H2O2 production and interleukin 1 (IL-1) production) at a dose of 250 micrograms/mouse on days 1 and 8, especially on day 8. Furthermore, SSG (250 micrograms/mouse) administered i.p. for 10 consecutive days significantly inhibited the experimental pulmonary metastasis of Lewis Lung Carcinoma (3LL) on BDF1 mice.

Animals↗
PubMed1991

[An experimental study on transmission of hand-arm vibration on the body of users].

Vibration forced into the hand-arm system was observed on the body surface during work with chain saw and under loading experiments by electrodynamic shaker in the laboratory, and factors related to transmission over joints were investigated using pig elbow joints constructed with ulna, radius and humerus. Vibration was measured according to IS 5349 and JIS C1511 between 8 and 1,000 Hz in vibration frequency. Vibration on the bone of pig foreleg conducted without attenuating its amplitude from the peripheral side to the central side between 8 and 1,000 Hz. On the other hand, vibration transmitted over joints damped its amplitude in higher frequency components rather than in lower frequency between 8 and 1,000 Hz. The decreasing ratio of transmitted vibration over joint was changed by the resonance of the soft tissues between the bones constructing the joint. The attenuation changed with the elastic modulus of the soft tissues. The peak frequency was considered to be the resonance because of the physical mass and elasticity. The harder the joint was tied, the stronger became the transmission, because the resonance moved to higher frequencies with increase in elastic modulus. In the loading test from the electrodynamic shaker to the hand-arm system of man, vibration on the soft tissues was transmitted on its surface as wave motion, when the vibration was observed over the skin on the soft tissues. Vibration reduced its amplitude at every joints especially above 100 Hz. The shape of the vibration attenuation curves varied according to the frequency and components of the chain saws.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Some aspects of hearing change in Meniére's patients.

Fifteen patients with Meniére's disease (8 male and 7 female) in whom as of December 1988 a follow-up audiovestibular study could be made for 2 to 10 years, and who received conservative treatment were assessed for prognosis of the disease, particularly for hearing. Hearing, when compared with the initial level, was deteriorated in 8 ears (by 60 dB HL or more in all cases), remained unchanged in 8 ears (41-68.8 dB HL) and improved in 2 ears (by 21.3 or 35 dB HL). The vertigo period was longer and attacks tended to occur more frequently in the groups with deteriorated hearing and with unchanged hearing than in the group with improved hearing. Patients whose hearing (during remission) dropped by more than 10 dB from the initial hearing level (during remission) within 3 years of the first audiovestibular examination tended to show a further declining hearing level afterwards. This was interpreted as indicating that the outcome of hearing can be predicted on the basis of observations (audiograms) made during the initial 3 years of the disease.

Adolescent↗
PubMed1991

Absorption and metabolism of pyridoxamine in mice. I. Pyridoxal as the only form of transport in blood.

[3H]Pyridoxamine was orally administered to mice in physiological amounts, and the distribution of isotope between the six recognized forms of vitamin B6 and pyridoxic acid was determined at different times in the intestine, liver, blood, and brain. After 7 min about 50% of the radioactivity in pyridoxamine had been absorbed by the intestine and transported to the blood and other organs. Labeled pyridoxal phosphate was found in the intestine and liver. Labeled pyridoxamine could not be detected in the peripheral blood, but substantial amounts of labeled pyridoxal and pyridoxal phosphate were found in the blood. However, when a large amount (40-140 nmol) was given, a significant amount of labeled pyridoxamine was found in the blood, together with labeled pyridoxal and pyridoxal phosphate. These results suggest that the intestine and/or liver play a major role in completely converting physiological amounts of pyridoxamine to circulating pyridoxal, which is then taken up and phosphorylated by other organs.

Absorption↗
PubMed1991

[Measurement of serum eosinophil cationic protein levels in patients with bronchial asthma--analysis according to various clinical backgrounds].

To evaluate the clinical relevance of serum eosinophil cationic protein (ECP) levels, we measured serum ECP levels in 126 asthmatic children, and investigated its relationship with some of the clinical backgrounds. Serum was separated at 1 hour after blood was drawn, and ECP was measured by radioimmunoassay. Serum ECP levels were significantly higher in the patients who had asthma attack within 24 hours than those who did not, and were higher in the patients who had asthma attack almost everyday for the past two weeks than those who had not. In addition, serum ECP levels were correlated with severity of asthma in the previous year, and the patients who had longer history of asthma showed higher levels of ECP. Among the patients who had asthma attacks at the time of blood sampling, serum ECP levels were higher in the patients in whom the attack lasted less than 12 hours than those more than 12 hours. However, no significant correlations were observed between serum ECP levels and the severities of attacks, between serum ECP levels and eosinophil counts. These results suggest that serum ECP level increases during the asthma attack, especially in its chronic active status. Serum ECP may reflect eosinophil activation in vivo and may be a better parameter than eosinophil counts. It is suggested that the measurement of serum ECP level may be useful to evaluate the clinical status of bronchial asthma.

Asthma↗
PubMed1991

A preliminary study on the function tests of the vibration syndrome in tropical rain forest workers.

Working situations and health hazards directly related to the work of the tropical rain forest workers were studied in Papua New Guinea. The results of the function tests of the vibration syndrome were reported in the preliminary step of this study. Among 61 workers including 16 chain saw operators no clear evidence was found that was related to the health effects of hand-arm vibration, but a possibility existed of an occurrence of subclinical dysfunction of peripheral circulation and peripheral neuropathies. The principal component analysis suggests that the reactiveness of peripheral circulation significantly reflects the duration of the chain saw operation.

Adult↗
PubMed1991

Mechanisms of inhibitions of DNA polymerase gamma by nucleotide analogues having anti-HIV activities.

Inhibition mechanisms of 5'-triphosphates of 3'-azido-3'-deoxythymidine (AZT-TP) and 3'-deoxythymidine (ddTTP) on extensively purified DNA polymerase gamma from bovine testes were examined by analysis of the products synthesized on singly primed M13mp18 single-stranded DNA or synthetic oligonucleotide template-primer in the presence of analogues. The results indicate that AZT-TP inhibits DNA polymerase gamma in competition with dTTP but is not incorporated into DNA, whereas ddTTP is incorporated into DNA and causes chain termination.

Animals↗
PubMed1991

Effects of DM-9384, a cyclic derivative of GABA, on amnesia and decreases in GABAA and muscarinic receptors induced by cycloheximide.

The effects of N-(2,6-dimethyl-phenyl)-2-(2-oxo-1-pyrrolidinyl)-acetamide [DM-9384], a cyclic derivative of GABA, were investigated in the cycloheximide (CXM)-induced amnesia animal model using the passive avoidance task. Pre- and post-training and pre-retention test administration of DM-9384 attenuated the CXM-induced amnesia as indicated by prolongation of step-down latency. Aniracetam, another cyclic derivative of GABA, also showed antiamnesic effects. Scopolamine, a muscarinic ACh receptor antagonist, and the GABA antagonists, picrotoxin and bicuculline, all antagonized the antiamnesic effects of DM-9384. CXM decreased the number of GABAA and muscarinic ACh receptor binding sites. DM-9384 not only inhibited this effect but actually increased the latter. These results suggest that DM-9384 attenuates CXM-induced amnesia by interacting with GA-BAergic and AChergic neuronal systems and enhancing protein synthesis in the brain.

Amnesia↗