Search PubMed⌕ Search

Biomedical subjects

A Matsui

Publications and source records attributed to A Matsui.

At least 163 records · Page 9Linked to original sources
PubMed1990

Effects of the diamond grit sizes of the commercial dental diamond points on the weight-load cutting of bovine enamel and glass-ceramic Typodont teeth.

To evaluate the effect of the diamond grit size of commercial dental diamond points on the dental cutting, we conducted weight-load cutting tests on bovine enamel and glass-ceramic typodont teeth using 3 different diamond grit sizes and air-bearing and ball-bearing air-turbine driven handpieces. With the transverse load applied on the diamond point varied between 20 and 80 g, we measured rotational cutting speed and cutting volume. Generally, increases in applied load caused decreases in rotational cutting speed and increases in cutting volume. The intensity of this trend, however, differed between grit sizes. Regular grit diamond points most strongly showed this tendency, while super-fine grit diamond points were least affected. Fine grit diamond points behaved in a manner similar to regular grit points.

Animals↗
PubMed1990

[Assessment and treatment of respiratory dysfunction in severely handicapped children: respiratory disorders during sleep].

In severely handicapped patients, chronic respiratory insufficiencies and recurrent hypoxemia especially during sleep are one of the major problems to take care of them. To clarify the pathophysiology of respiratory disorders during sleep, we examined 5 severely handicapped patients with no respiratory distress during wakefulness, but with signs of latent respiratory insufficiency by means of polygraphical all-night study including the arterial oxygen saturation (SaO2) monitoring. In the severely handicapped patients, sleep hypoxemia occurred frequently. The value of SaO2 decreased in proportion to the intensity of apnea determined by polygraph. The relationship between the value of SaO2 and sleep stage was variable in each patient. Four patients had mainly obstructive respiratory disorders and one had a central type respiratory disorder. The density of REM stage decreased in the obstructive type. In the central type, the repeat of REM stage with normal REM density was not observed. In one patient with obstructive type and one with central type, hypoxemia was improved with an increased number of REM stage by O2 inhalation.

Adult↗
PubMed1990

[Studies on the roentgenological differentiation between complex and simple bowel obstruction].

We studied 81 cases of organic bowel obstruction. In complex obstruction 7 cases out of 25 (28%) were diagnosed on the plain film before operation, although in simple obstruction 54 cases out of 56 (96%). But in retrospective evaluation of the plain films, we noticed that in some cases of complex obstruction, marked small bowel obstruction and ascites were seen from the onset, which were never seen in simple obstruction. We considered this finding as the key point for the roentgenological differentiation between complex and simple obstruction.

Diagnosis, Differential↗
PubMed1989

Primary role of calcium ions in arachidonic acid release from rat platelet membranes. Comparison with human platelet membranes.

The liberation of arachidonic acid (AA) was investigated in platelet membranes prelabelled with [3H]AA. In rat platelet membranes, Ca2+ at concentrations over several hundred nanomolar induced [3H]AA release, with a concurrent decrease in 3H radioactivity of phosphatidylethanolamine and phosphatidylcholine. Some 4-6% of total radioactivity incorporated into platelet membrane lipids was released at 1-10 microM-Ca2+, which is nearly equivalent to that attained in agonist-stimulated platelets. Formation of lysophospholipids in [3H]glycerol-labelled membranes and decrease in [3H]AA liberated by the phospholipase A2 inhibitors mepacrine and ONO-RS-082 suggest that [3H]AA release is mainly catalysed by phospholipase A2. In intact platelets agonist-stimulated [3H]AA release was markedly decreased in the absence of extracellular Ca2+ or in the presence of the intracellular Ca2+ chelator quin 2. These results indicate that in rat platelets the rise of intracellular Ca2+ plays a primary role in the activation of phospholipase A2. In contrast, Ca2+ even at high millimolar concentrations did not effectively stimulate [3H]AA release in human platelet membranes. Thus factor(s) additional to or independent of Ca2+ is required for the liberation of AA in human platelets.

Animals↗
PubMed1989

Lower leg reconstruction using a sural fasciocutaneous flap.

The fasciocutaneous flap in the lower leg has been widely used since Pontén's 1981 report. The cutaneous artery running along the sural nerve--known as the superficial sural artery--has an important role in the blood supply of the fasciocutaneous flap in the lower leg as stated by Haertsch. The superficial sural artery has great variation with regard to its location and the origin of the vessel. The cutaneous artery is intimately connected to the sural nerve or the lateral sural nerve. It may run along the sural nerve or along the lateral sural nerve. We examined this vessel in 10 cadaver dissections and applied it in 17 clinical cases of pedicled, island, and free flaps. The island sural fasciocutaneous flap is particularly versatile for the reconstruction of the soft tissue defect around the knee joint. The operative procedure involving the island fasciocutaneous flap and the characteristics of this sural fasciocutaneous flap are described.

Adolescent↗
PubMed1989

Comparison of rotational speeds and torque properties between air-bearing and ball-bearing air-turbine handpieces.

We examined the effects of air pressure on the free-running speed of air-bearing and torque-type ball-bearing air-turbine handpieces. The air pressure for the former should be kept at a certain high level to maintain the stable super-thin air-bearing film and to provide the quasi-constant speed of around 420,000 to 480,000 rpm. On the other hand, the air pressure for the latter could be adjusted to provide some varieties of speeds, ranging from about 150,000 to 320,000 rpm. Subsequently, to compare torque properties and cutting effectiveness between these two handpieces, weight-load cutting tests were conducted, using a glass-ceramic workpiece and a commercial diamond point. It was confirmed that the air-bearing handpiece had the lower torque power but exhibited better cutting effectiveness, compared with its counterpart.

Air Pressure↗
PubMed1988

Complete cDNA encoding a putative phospholipase C from transformed human lymphocytes.

Phosphoinositide-specific phospholipase C (PLC) is a crucial enzyme in transmembrane signaling. A cDNA encoding the putative phospholipase C was cloned from human lymphocytes that were transformed by infection with Epstein-Barr virus. The deduced amino acid sequence of the cDNA accounted for 146.1 kDa of the molecular mass of the complete enzyme and showed 50.2% sequence similarity to bovine brain PLC. This cDNA contained regions, the sequences of which were similar to those of some tyrosine kinase-related oncogene products. Northern blotting demonstrated that the mRNA for this PLC is expressed in human promyelocytic leukemia cells (HL-60). Since the other cloned cDNAs for PLCs could not hybridize with the RNA from this cell, it is strongly suggested that the gene obtained here encodes an additional isozyme of PLC in blood cells.

Amino Acid Sequence↗
PubMed1988

Quantitative relationship between the stimulus intensity and the response magnitude in the tail flick reflex.

The purpose of the present study was to investigate the quantitative relation between the stimulus intensity and the response magnitude of the tail flick reflex. The EMG of a tail muscle was recorded from the extensor caudae medialis (ECM) muscle in the side contralateral to heat stimulation, and the area of integrated EMG for 1 sec was measured as the magnitude of EMG activity. The minimum temperature to the onset of the EMG was 42.3 +/- 0.4 degrees C. The relation between the stimulus intensity and the magnitude of an integrated EMG followed a power function with an exponent of about 8.5. The magnitude of an integrated EMG was decreased by about 50% of the control by an intraperitoneal administration of morphine (0.5 mg/kg). These results suggest that tail flick reflex is closely related to painful sensation, and that EMG activity of the ECM muscle is applicable as an electrophysiological indicator to noxious stimulation of the tail and an expressible indicator of the magnitude of pain.

Animals↗
PubMed1988

Enhanced glucose metabolism and impaired placental function in hypoxic pregnant rats.

Glucose metabolism using 2-deoxy-2-[18F]fluoro-D-glucose [( 18F]FDG) was studied in experimental hypoxia (10% oxygen concentration) of pregnant rats with special attention given to the placental function. After an i.v. injection of [18F]FDG, the uptake of 18F increased with time in the maternal brain, placenta and fetus of control rats. In the hypoxic condition, the uptake in these tissues was enhanced significantly, especially in the maternal brain and fetal heart, brain and lungs. A double-label autoradiography with [18]FDG and [14C]iodoantipyrine [( 14C]IAP) was performed to elucidate changes of the placental function in the hypoxic condition. The [18F]FDG image revealed a higher accumulation in the maternal side of the placenta of a control pregnant rat than in its fetal side. [18F]FDG uptake increased in the fetal brain and heart of hypoxic rats. The [14C]IAP image demonstrated that in the control rat there was a clear border zone on the maternal side of the placenta with very low permeability into the fetus. On the other hand, a high and heterogenous accumulation in both placenta and fetal organs was shown in hypoxic rats. We interpret this data to suggest that in a hypoxic condition the function of the placenta as a barrier system is impaired.

Animals↗
PubMed1988

Zellweger-like syndrome with detectable hepatic peroxisomes: a variant form of peroxisomal disorder.

A male infant with typical clinical and biochemical findings of Zellweger syndrome, but in whom hepatic peroxisomes were detected by electron microscopy, had profound hypotonia, hepatomegaly, typical facial appearance including large fontanelle and frontal bossing, convulsions, panaminoaciduria, and hyperammonemia. He died of liver failure at age 5 months. There were increased levels of very long chain fatty acids and trihydroxycoprostanic acid in serum, and increased excretion of dicarboxylic acids and tyrosine metabolites in the urine. Levels of peroxisomal enzymes, acyl coenzyme A oxidase, bifunctional protein, 3-ketoacyl coenzyme A thiolase, and dihydroxyacetone phosphate acyltransferase in the liver tissue from the patient were all deficient, findings consistent with Zellweger syndrome. However, immunocytochemical study and electron microscopic examination of the liver at autopsy revealed that hepatic peroxisomes were present at a level similar to that in a control subject. These observations suggest further heterogeneity in Zellweger syndrome and a different pathogenesis in this variant case.

Bile Acids and Salts↗