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Biomedical subjects

T Matsui

Publications and source records attributed to T Matsui.

At least 595 records · Page 33Linked to original sources
PubMed1993

The effects of low-frequency ultrasound on the inner ear: an electrophysiological study using the guinea pig cochlea.

By examining 218 albino guinea pigs, electrophysiological methods were used to investigate the effects of low frequency ultrasound at moderate sound pressure levels after long-term exposure to the inner ear. From 10 kHz to 28 kHz, low frequency ultrasound below 100 dB SPL induced significant changes in cochlear microphonics, elevated thresholds and decreased maximum output voltage of action potentials and decreased absolute values of negative potentials of the endocochlear potentials.

Acoustic Stimulation↗
PubMed1993

Infectivity and sporogony of Caryospora-type oocysts of Isospora rivolta obtained by heating.

The infectivity and sporogony of Caryospora-type oocysts of Isospora rivolta obtained by heat treatment were examined. Fresh unsporulated oocysts of I. rivolta were heated at 50 degrees C for 5 min, then poured into a cold 2% potassium dichromate solution and incubated at 25 degrees C. To observe the stage of sporulation, 100 oocysts were examined at 2-h intervals after incubation. The earliest sporulated oocysts were observed at 14 h and the sporulation time was 22 h, similar to that of nontreated oocysts. To determine the infectivity, only Caryospora-type oocysts were collected after sporulation and inoculated orally into cats and mice. The mice were killed at 7 days after inoculation, and their mesenteric lymph nodes and spleens were fed to other cats. All of these cats shed oocysts. The newly discharged oocysts developed into the Isospora type after sporulation. These results suggest that the Caryospora-type oocysts transformed only morphologically after heat treatment and were as infective as the nontreated oocysts to host animals.

Animals↗
PubMed1993

Scheduled feeding caused activation of dopamine metabolism in the striatum of rats.

The effects of a time-restricted feeding schedule on dopamine (DA) release and its metabolites output in the striatum of freely moving rats were studied. Rats had access to food for only 2 h daily for 7 successive days. On the 1st or 7th day, the extracellular concentrations of DA, 3,4-dihydroxyphenylacetic acid (DOPAC), and homovanillic acid (HVA) in the ventrolateral striatum were measured by in vivo brain microdialysis during 2 h of exposure to food-related stimuli followed by 2 h of access to food. Extracellular concentrations of DA and its metabolites did not change during the period of exposure to food-related stimuli or during feeding on the 1st day. On the 7th day, extracellular DOPAC and HVA concentrations increased significantly during 2 h of feeding, but not during exposure to food-related stimuli, compared with basal levels. Extracellular DA concentration did not change significantly. These results indicate that scheduled feeding caused activation of DA metabolism in the ventrolateral striatum and facilitate feeding-related motor activity in feeding behavior.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1993

Affinity chromatographic purification of tetrodotoxin by use of tetrodotoxin-binding high molecular weight substances in the body fluid of shore crab (Hemigrapsus sanguineus) as ligands.

A purification method for tetrodotoxin (TTX), based on affinity chromatography using the TTX-binding high mol. wt substances in the body fluid of shore crab (Hemigrapsus sanguineus) as ligands, was developed. This method was particularly useful for analysis of TTX in biological samples with low concentrations of TTX. The affinity gel prepared was highly specific for TTX, having no ability to bind 4-epi-TTX and anhydro-TTX as well as saxitoxin.

Ammonium Sulfate↗
PubMed1993

Vesicoureteral reflux in infants under one year old. Follow-up study and consideration on development of renal scarring.

In an attempt to clarify reflux nephropathy (RN), 67 infants aged under one year with vesicoureteral reflux (VUR) were retrospectively classified into two groups, non-surgical and surgical. They were evaluated on VUR grading, VUR spontaneous cessation rate, and incidence of scarring. As a whole, spontaneous cessation rate was 61 percent. The cessation rate was higher for infants with lower VUR grading. The average age at cessation was 2.5 years. Some patients showed no scarring at presentation despite severe VUR. However, most cases of renal scarrings at the time of presentation belonged to grade IV or V. Scarring advanced in 3 kidneys of the non-surgical group and in 13 kidneys of the surgical group. Of these 16 kidneys, 7 were rated as grade IV and 9 as grade V. An association between development of scarring and recurrent urinary tract infections was suggested.

Cicatrix↗
PubMed1993

Comparative studies of asparagine-linked sugar chains of immunoglobulin G from eleven mammalian species.

1. Asparagine-linked sugar chains released by hydrazinolysis from IgGs of porcine, equine, bovine, goat, ovine, canine, rabbit, guinea-pig and rat were comparatively analyzed by microsequencing and lectin affinity chromatography. 2. Sugar chains of all IgGs basically consisted of biantennary complex-type oligosaccharides containing 0-2 sialic acid residue(s). More than 70% of the oligosaccharides were neutral, except for guinea-pig IgG, and fucosylated trimannosyl core structures were dominant except for rabbit IgG. Bisecting N-acetylglucosamine residue was absent in porcine and equine IgGs. 3. A large quantity of galactose-less oligosaccharides were present in IgGs of porcine, equine, canine and rat.

Animals↗
PubMed1993

Alterations in protein kinase C activity and membrane lipid metabolism in cerebral vasospasm after subarachnoid hemorrhage.

Changes in protein kinase C (PKC) activity, membrane lipid metabolism, and the extent of 20-kDa myosin light chain (MLC) phosphorylation in spastic cerebral basilar arteries were examined by using the beagle "two-hemorrhage" model of subarachnoid hemorrhage. In spastic arteries at days 4 and 7, cytosolic PKC activity showed a decrease of 40-45% with no significant changes in membrane PKC activity as compared with nonspastic control arteries. Cytosolic PKC activity of the day 14 arteries returned toward the normal control level with the remission of vasospasm. Western blot analysis of the PKC isoforms revealed that the amounts of PKC alpha and PKC epsilon but not PKC zeta were decreased in spastic arteries. As compared with nonspastic arteries, spastic arteries showed higher rates of incorporation of [3H]choline into phosphatidylcholine (PC) and [14C]ethanolamine into phosphatidylethanolamine (PE), but not of [3H]myoinositol into phosphoinositides, suggesting the stimulated turn-over of PC and PE. The extent of 20-kDa MLC phosphorylation was not increased in the spastic arteries at days 4 or 7 as compared with that in the nonspastic control arteries. These results demonstrate that PKC activity and related membrane lipid metabolism are altered in spastic basilar arteries after subarachnoid hemorrhage.

Animals↗
PubMed1993

Effects of alanine and glutamine administration on the inhibition of liver regeneration by acute ethanol treatment.

We studied the effects of alanine and glutamine administration on the inhibition of liver regeneration by acute ethanol treatment after partial hepatectomy (PH) in rats. When rats were dosed i.p. with ethanol at 2 g/kg at the time of PH, DNA synthesis 48 hr after PH was significantly inhibited, but it was completely reversed by the combined use of alanine and glutamine. Although hepatic ornithine decarboxylase (ODC) activity in the alcohol-treated group 4 hr after PH was significantly inhibited, there was a tendency towards recovery of the ODC inhibition in the alanine and glutamine-treated group. The putrescine (PUT) level in liver which was decreased by ethanol was also increased by the administration of alanine and glutamine. However, the levels of spermidine (SPD) and spermine (SPM) in liver were unaffected either by ethanol or by alanine and glutamine. These results suggest that alanine and glutamine show a protective effect on the inhibition of liver regeneration caused by acute ethanol treatment by improving polyamine metabolism, particularly by increasing hepatic PUT levels.

Alanine↗
PubMed1993

Assessment of the chemical form of gaseous 35S species produced during the production of H3(32)PO4.

The chemical form of gaseous 35S species produced during the production of H3(32)PO4 was characterized in order to reduce 35S discharge by understanding its production mechanism and chemical reactivity. An air sample was evacuated from the cell in which the H3(32)PO4 production was being carried out and collected in a sample gas reservoir. Gaseous sulfur species contained in the sample were condensed in a cold trap maintained at -180 degrees C and analyzed by means of gas chromatography using a flame photometric detector. Sulfur dioxide (SO2) was the only sulfur species detected. Equilibrium constant calculations showed that SO2 would be expected to be the predominant species produced by reactions of sulfur molecules (Sn:n = 2-8) with oxygen in air and that the quantity of SO2 produced would be reduced by heating the irradiated sulfur target under vacuum or in atmospheres of inert gases.

Chromatography, Gas↗
PubMed1993

Human neuroblastoma cells express alpha and beta platelet-derived growth factor receptors coupling with neurotrophic and chemotactic signaling.

Both platelet-derived growth factor (PDGF) A- and B-chains are expressed in mammalian neurons, but their precise roles still remain to be clarified. In the present studies, we examined the expression of two PDGF receptor genes in human tumor cell lines derived from neural crest. The expression of alpha and/or beta PDGF receptors was detected in a wide variety of neural crest-derived human tumor cell lines such as neuroblastoma, primitive neuroectodermal tumor, and Ewing's sarcoma by RNA blot analysis, and confirmed by immunoblot analysis. We have also demonstrated that PDGF receptors on the human neuroblastoma cell lines were biologically functional. Accordingly, chemotactic and mitogenic activities were induced by either PDGF-AA or PDGF-BB in serum-free medium. PDGF isoforms as well as nerve growth factor induced morphological changes showing neuronal cell maturation. Moreover, PDGF coordinately increased the levels of the transcript of the midsize neurofilament gene. The neuroblastoma cell lines also expressed the transcripts of PDGF A- and B-chains. These findings suggest that PDGF isoforms are involved not only in the promotion of the neuroblastoma cell growth, but also in neuronal cell migration, growth, and differentiation in human brain development.

Amino Acid Sequence↗
PubMed1993

The hemodynamic effects of prolonged albumin administration in beagle dogs exposed to experimental subarachnoid hemorrhage.

The hemodynamic effects of hyperdynamic hemodilution induced by prolonged (for 1 week) intravenous albumin or low-molecular-weight dextran administration were studied in the beagle two-hemorrhage model. Drug infusion was started immediately after the induction of a subarachnoid hemorrhage and continued for 7 days thereafter, according to the following treatment schedule: Group 1 (physiological saline); Group 2 (10% low-molecular-weight dextran, 0.8 g/kg per day); Groups 3, 4, and 5 (25% albumin, 1, 2, and 3 g/kg per day, respectively). On Day 0 (before subarachnoid hemorrhage) and Day 7, the cardiopulmonary parameters and the blood flow of the vertebral artery (VAF) were measured by the use of the Swan-Ganz catheter and an electromagnetic flowmeter, respectively. Cerebral angiography was carried out on Days 0 and 7. Only the albumin-treated groups showed a significant increase in plasma osmotic pressure, cardiac output, and VAF, as well as a decrease in the hematocrit on Day 7. The increase in cardiac output and VAF was maximal in Group 4. In Group 5, signs of pulmonary edema in the chest roentgenogram were noted in two of the four animals. The angiographic spasm of the basilar artery on Day 7 was not significantly ameliorated by either albumin or dextran. In the albumin-treated groups, the VAF was shown to increase in parallel with the increase of the cardiac output, within the range between 50 and 150%. Thus, this study indicates that the hemodynamic changes induced by prolonged albumin administration improve the cerebral circulation hindered by chronic vasospasm, whereas the increase in cardiac output is considered to be the most reliable indicator regarding the determination of the optimal dosage of albumin.

Animals↗
PubMed1993

Beneficial effect of prolonged administration of albumin on ischemic cerebral edema and infarction after occlusion of middle cerebral artery in rats.

This study compared the therapeutical effect of the prolonged administration of albumin, 2 g/kg body weight per day, with that of saline or dextran, 0.8 g/kg body weight per day, on cerebral ischemia, using an occlusion of the middle cerebral artery in the rat. Brain water, sodium, and potassium contents were measured 72 hours after middle cerebral artery occlusion. The volume of infarction was represented as volume index, which is a total of the infarction area measured in the five brain slices at 168 hours after middle cerebral artery occlusion. The postischemic administration of albumin at the dose tested elucidated an antiedema effect and reduced the infarction size after regional ischemia in rats. These results strongly support the idea that hemodilution therapy with colloids such as albumin has wide usage as a treatment of patients with ischemic cerebral stroke.

Albumins↗
PubMed1993

Inhibition of angiotensin I-converting enzyme by Bacillus licheniformis alkaline protease hydrolyzates derived from sardine muscle.

Hydrolyzates which inhibit the angiotensin I-converting enzyme (ACE) were prepared from sardine muscle by Bacillus licheniformis alkaline protease. Considering the practical application of preparations as a functional food material, the best proteolytic conditions with respect to taste, solubility and ACE inhibitory activity were a 0.3 wt% addition of the enzyme and 17-h proteolysis at 50 degrees C and pH 9.0. The preparations under these conditions had potent activity (IC50 = 0.26 mg protein/ml). Fractionation of the preparations on an ODS column with ethanol resulted in the production of more potent inhibitors. The most potent activity was obtained when eluting with 10% ethanol (IC50 = 0.015 mg protein/ml). This fraction was apparently rich in acidic amino acids, poor in hydrophobic ones, and effective for use as a physiologically functional food material by virtue of little bitterness, a fish odor and powerful ACE inhibitory activity.

Amino Acid Sequence↗
PubMed1993

Familial scrapie cases with shortened incubation periods.

Two familial scrapie cases successively occurred in 29-month-old and 30-month-old Corriedale dams and in three of their offspring as early as 10-19 months of age in a small flock. They showed ataxy but no pruritus. Histopathological and immunochemical examinations of those sheep revealed vacuolation of nerve cells in brain tissue and presence of PrPsc, a component of scrapie-associated fibrils, in brain, spleen and lymph node tissues. We discuss about shortened incubation periods and lacking pruritus in the present scrapie cases.

Animals↗
PubMed1993

[Studies on interdigestive intestinal motility of the orthotopic allotransplanted canine small bowel].

We evaluated interdigestive motor patterns in the allotransplanted small bowel, in comparison with orthotropic allotransplanted canine jejunoileum and orthotropicaly autotransplanted canine jejunoileum or intact ones by using strain gage force transducers which were sewn to the serosal surfaces of the duodenum, jejunum and ileum. Interdigestive intestinal motility of each conscious dogs was recorded at 2 weeks, 4 weeks and 8 weeks after each operation. 1. No significant differences were recognized on the mean durations of Interdigestive migrating contractions (IMC) of the duodenum among three groups. 2. Interdigestive migrating contractions (IMC) appeared at the autotransplanted jejunoileum with shorter duration than duodenum, and lacked of coordination between the intact duodenum and the transplanted jejunoileum for at least 8 weeks after the operation. 3. IMC also appeared at the allotransplanted jejunoileum with shorter duration than duodenum and lacked of coordination between the intact duodenum and the transplanted jejunoileum for at least 8 weeks after the operation. These characteristic motor patterns were similar to those of autotransplanted dogs. These observations suggest that intrinsic nervous system, believed to be important for initiation of the IMC of small bowel, were preserved even in the allotransplanted small bowel. Thereafter, effective immunosuppression must allow small bowel allotransplantation to become clinical reality.

Animals↗
PubMed1993

Successful treatment of refractory polymyositis with pulse intravenous cyclophosphamide and low-dose weekly oral methotrexate therapy.

A 36-year-old woman gradually developed dysphagia and muscle weakness of the lower extremities. Diagnosis of polymyositis was given from elevation of serum creatine kinase and pathological findings of a muscle biopsy. Despite oral prednisolone and intravenous pulse methylprednisolone therapy, her muscle weakness persisted, and then pulse intravenous cyclophosphamide (IVCY) therapy was initiated and repeated five times in total, which resulted in significant improvement in muscle strength. Thereafter, weekly administration of methotrexate at low dosage further normalized the serum creatine kinase level. We may conclude that IVCY and low-dose weekly methotrexate together could be an alternative in refractory polymyositis.

Administration, Oral↗
PubMed1993

New mutation of the myelin P0 gene in a pedigree of Charcot-Marie-Tooth neuropathy 1.

P0, the major structural protein of peripheral myelin, is a homophilic adhesion molecule with a single immunoglobulin (Ig) domain, which contains a single N-linked glycosylation site and two cysteines. We have previously reported four different mutations of the myelin P0 gene in four families of Charcot-Marie-Tooth neuropathy type 1 (CMT1). In this study we found a new mutation of the myelin P0 gene in a small family of CMT1. The affected persons had an A - to - G substitution of nucleotide 245 of the myelin P0 gene in one allele, leading to a cysteine substitution for tyrosine82 in the extracellular Ig-domain. An additional cysteine in the extracellular domain may form a disulfide bond and cause an inappropriate change in the tertiary structure of the functional Ig-domain of P0.

Adolescent↗