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S Yuasa

Publications and source records attributed to S Yuasa.

At least 145 records · Page 8Linked to original sources
PubMed1990

Retrovirus-mediated gene transfer into mouse cerebellar primary culture and its application to the neural transplantation.

To develop a procedure for the transplantation of genetically modified brain primary cells, we transplanted cultured mouse cerebellar cells infected with recombinant retroviruses into the cerebella of adult mice and examined the expression of introduced gene-products in the host cerebellum after transplantation. After infection of cultured cerebellar cells with recombinant retroviruses harboring chloramphenicol acetyltransferase (CAT) gene, we selected only virus-infected cells for transplantation by culturing the cells in medium containing G418 for 3 weeks. CAT was continuously expressed in the cultured cerebellar cells during the 3-week incubation, but by immunoblotting analysis with antiglial fibrillar acidic protein (GFAP) or antineurofilament protein (NFP) antiserum the population of cultured cerebellar cells was found to change during the incubation. Immunocytochemical analyses using anti-CAT antiserum demonstrated that the transplanted cell mass containing CAT-positive cells was detectable in the cerebellum up to 3 weeks, but not 3 months after the transplantation of G418-selected cells into the cerebella of 7-week-old mice.

Animals↗
PubMed1990

Transplantation of embryonic olive in the climbing-fiber-deprived adult rat cerebellum: synaptogenesis on host Purkinje dendritic spines by donor climbing fibers.

Synaptic formation by donor climbing fibers on the host Purkinje spines was observed in our experiments. In the adult rat cerebellum where the inferior olive and climbing fibers had been destroyed by intraperitoneal injection of 3-acetylpyridine, the medullary embryonic 14-16-day (E14-E16) tissue containing the olive was grafted. After 3 weeks, climbing-fiber-type preterminals bearing closely-packed round vesicles were found that established synaptic contacts on dendritic spines of the host Purkinje cells. Quantitative analysis indicates the increment of newly-formed climbing presynaptic terminals, the number of which was statistically significant (P less than 0.01).

Afferent Pathways↗
PubMed1990

Development of the rodent cerebellum and synaptic re-formation of donor climbing terminals on spines of the host Purkinje dendrites after chemical deafferentation.

Reinnervation of host Purkinje cells by donor climbing fibers was observed in the following experiments. Medullary primordial tissue (from E14-E16) containing the inferior olive was grafted into a host rat cerebellum, in which the inferior olivary complex and climbing fibers had been destroyed by intraperitoneal injection of 3-acetylpyridine (3-AP). After 3 weeks, immature as well as mature types of climbing fiber terminals bearing packed round vesicles were found that had established synaptic contacts on dendritic spines of the host Purkinje cells. Quantitative analysis at the ultrastructural level has been carried out. The main results are as follows. (1) The number of preterminals that formed synaptic contacts with spines of the host Purkinje dendrites in the transplanted material increased by 3.4-fold compared to the control (3-AP-treated non-grafted material). (2) The number of mature climbing-type preterminals increased from 0.3-0.9% to 5% after grafting (cf. 22% in normal brain tissue), and the number of immature climbing-type preterminals also increased from 2-10% (control) to 20% after grafting. These changes were statistically significant (P less than 0.01). (3) The number of parallel-type preterminals increased from 13% (control) to 27% after grafting, which was also statistically significant (P less than 0.01). Thus, it appears that the donor climbing fibers grow and develop to find unoccupied spines on the host Purkinje dendrites and establish synaptic contacts, and also that the host parallel fibers may generate axonal sprouts to search their new targets and ultimately to form synaptic contacts with unoccupied spines. In the process of re-modeling the brain, competition for targets is likely to occur between the two kinds of axonal processes, i.e. the donor climbing fibers and the host parallel fibers.

Animals↗
PubMed1990

Formation of sulfate from L-cysteine in rat liver mitochondria.

Formation of sulfate in rat liver mitochondria was studied. About 0.1 mumol of sulfate was formed in mitochondria from 1 g of liver in 60 min when 10 mM L-cysteine was used as the substrate. Addition of either 10 mM 2-oxoglutarate or 10 mM glutathione to this system increased sulfate formation 3 to 4 times. The addition of both 2-oxoglutarate and glutathione resulted in a 20-fold increase in sulfate formation. Sulfate formation in the presence of 5 mM L-cysteine was 58% of that with 10 mM L-cysteine. L-Cysteine-glutathione mixed disulfide was not a good substrate, indicating that this mixed disulfide was not an intermediate of sulfate formation in the present system. Incubation of 3-mercaptopyruvate with rat liver mitochondria also resulted in sulfate formation, and the addition of glutathione accelerated it. Formation of sulfite and thiosulfate was also detected. These results indicate that sulfate is produced in mitochondria, at least in part, from L-cysteine through the transamination pathway (3-mercaptopyruvate pathway).

Animals↗
PubMed1990

Excretion of 3-mercaptolactate-cysteine mixed disulfide, sulfate and taurine in human urine before and after oral administration of sulfur-containing amino acids.

The excretion of 3-mercaptolactate-cysteine mixed disulfide [S-(2-hydroxy-2-carboxyethylthio)-L-cysteine, HCETC], sulfate and taurine in the urine of normal adults was investigated before and after oral administration of L-cysteine and related sulfur-containing amino acids. Before the loading of amino acids, the excretion (mean +/- SD) per kg of body weight per day of HCETC, free sulfate and taurine was 0.096 +/- 0.042, 305.7 +/- 66.1 and 31.9 +/- 8.7 mumols, respectively. After the loading of L-cysteine (800 mumols/kg of body weight), the average excretion in the 24-h urine of HCETC increased 2-fold and that of taurine increased 1.6-fold. The average excretion of free sulfate after the L-cysteine loading was 989.4 +/- 145.1 and 388.8 +/- 51.6 mumols/kg per day in the first and second 24-h urine, respectively, indicating that the sulfur corresponding to 85% of the L-cysteine loaded was excreted as free sulfate in 24 h. Administration of L-cystine (400 mumols/kg) resulted in similar results. The increase in HCETC after L-cysteine or L-cystine administration indicates that L-cysteine is metabolized in part through the transamination pathway (3-mercaptopyruvate pathway) and that an equilibrium exists between the intake and excretion of sulfur in humans.

Administration, Oral↗
PubMed1990

Determination of hypotaurine and taurine in blood plasma of rats after the administration of L-cysteine.

A method for the simultaneous determination of hypotaurine and taurine was developed. The method consisted of the elimination of urea, which interfered with the determination of hypotaurine, by immobilized urease, and determination of hypotaurine and taurine with an amino acid analyzer. The analyzer equipped with a cation-exchange column was operated at 32 degrees C with 0.2 M sodium citrate buffer, pH 2.8. Using this method, the dynamics of hypotaurine and taurine in blood plasma of rats was studied after the intraperitoneal injection of L-cysteine. The concentration of cysteine reached the maximum 1 h after L-cysteine loading. The concentration of hypotaurine and taurine increased in parallel and reached the maximum 2 h after L-cysteine loading. These changes seem to indicate the precursor-product relationship of these substances and the rapid conversion of hypotaurine to taurine in vivo.

Animals↗
PubMed1990

[Evaluation of the changes in intracranial water, sodium, phosphorus metabolites and intracellular cerebral pH in rats with acute dilutional hyponatremia].

Although most prominent among the clinical manifestations associated with hyponatremia are central nervous system (CNS) symptoms, the alterations in brain function remain poorly understood. In the present study, the alterations in intracellular cerebral pH and intracranial water, sodium and phosphorus metabolites content in rats with acute dilutional hyponatremia were examined by using an in vivo nuclear magnetic resonance (NMR) technique which noninvasively provides continuous informations on intracellular phenomena. Acute dilutional hyponatremia was induced on anesthetized male Sprague-Dawley rats by intraperitoneal injection of distilled water with an initial dose of 10 ml/100 g bw, followed by an additional dose of 5 ml/100 g bw 40 min later. Arterial blood sampling and NMR measurements were made before and every 60 min after the initial injection of distilled water. The treatment with distilled water resulted in dramatic falls in serum Na, Cl and osmolality at 60 min after water loading (Na; from 143.4 +/- 2.6 to 112.3 +/- 1.3 mmol/l, Cl; from 101.02 +/- 2.2 to 78.4 +/- 5.4 mmol/l, Osm; from 306.3 +/- 5.8 to 247.3 +/- 7.3 mOsm/kg H20). 1H-NMR imaging showed the accumulation of brain water as dilutional hyponatremia developed. Intracranial Na content measured by 23Na-NMR spectroscopy decreased significantly at 60 min after of water loading to about 70% of that observed under control condition. Since it has been demonstrated that solute extrusion from the brain with resultant reduction of brain swelling occurs within 60 min after the dilution, this result may be, at least in part, explained by this protective mechanism.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1990

[Influences of composition on brush wear of composite resins. Influences of particle size and content of filler].

The influences of the composition on abrasion resistance of composite resins were examined using various experimental composite resins which had various matrix resin, filler size and content. The abrasion test was conducted by the experimental toothbrush abrasion testing machine developed in our laboratory. Three series of heat-curing composite resins were tested. One series was made from a Bis-MPEPP or UDMA monomer, and a silica filler with an average particle size of 0.04, 1.9, 3.8, 4.3, 7.5, 13.8 and 14.1 microns. The filler content of this series was constant at 45 wt%. The second series contained a silica filler of 4.3 microns in a content ranging from 35 to 75 wt%. The third series contained a microfiller (0.04 microns) and macrofiller (4.3 microns) in total content of 45 wt%. In this series, the microfiller was gradually replaced by 5, 15, 25 and 45 wt% of the macrofiller. The results obtained for these three series indicated that the abrasion resistance of composite resins was controlled by the inorganic filler, mainly filler size and content. The abrasion loss did not vary with the difference of matrix resin. When the particle size of the filler was below about 5 microns, the abrasion resistance decreased markedly with the decrease in filler size. The composite resin which contained a 0.04 or 1.9 micron filler was less resistant to toothbrush wear than the unfilled matrix resin. However, the microfiller also contributed to abrasion resistance when used in combination with the macrofiller, although abrasion resistance decreased with the increase in the microfiller concentration. The increase of filler content clearly improved the abrasion resistance when used the macrofiller. The analysis of these results and SEM observations of the brushed surfaces of samples suggested that the toothbrush abrasion was three-body abrasion caused by the abrasive in the toothpaste, and affected by the difference in the particle size between abrasive and filler, and between the abrasive size and the interparticle distance of the filler.

Absorption↗
PubMed1990

[Hyponatremia in isolated deficiency of adrenocorticotropic hormone: role of a decrease in aldosterone secretion independent of antidiuretic hormone excess].

We report a case of 47-year-old woman with an isolated deficiency of adrenocorticotropic hormone. She was admitted complaining of fatigue and frequent loss of consciousness. The patient developed severe hyponatremia (100 mEq/l) after five days of the admission. Her plasma renin activity and plasma aldosterone concentration were low though she was dehydrated. After the treatment of dehydration, plasma osmolality was low but high plasma antidiuretic hormone (ADH) level sustained. Both high urinary sodium excretion and low urinary aldosterone excretion still remained after one month of replacement therapy with prednisolone. But, glomerular filtration rate and a response of urinary volume to acute water loading were normalized. These results suggested that severe hyponatremia of the patient was caused by an inappropriate secretion of ADH and suppression of renin-aldosterone system. We consider the suppression of renin-aldosterone system was partially independent of an inappropriate secretion of ADH.

Adrenocorticotropic Hormone↗
PubMed1990

[Angiotensin and prostaglandins in the pressure-natriuresis response in rats].

The possible roles of angiotensin and prostaglandins as humoral mediators of the pressure-natriuresis response were studied in anesthetized Sprague-Dawley rats. Neural and other hormonal influences on the kidney were held constant by denervating the kidney and by maintaining fixed high plasma levels of aldosterone, corticosterone, vasopressin and norepinephrine by continuous intravenous infusion. Acute elevation of arterial pressure by tightening the ligature placed around the abdominal aorta below the renal artery produced marked increases in urine flow and sodium excretion with no detectable changes in renal blood flow or glomerular filtration rate. In rats undergoing a saline diuresis, the pressure-natriuresis response was markedly inhibited by intravenous infusion of angiotensin II at a rate of 10 ng/kg/min. Blockade of prostaglandin synthesis with indomethacin also reduced the pressure-natriuresis response in the presence of low-dose (2 ng/kg/min) of angiotensin II, but indomethacin alone did not affect significantly. On the other hand, in rats with hydropenia indomethacin alone significantly inhibited the sodium excretory response to changes in arterial pressure. This indomethacin-induced inhibitory effect on the pressure-natriuresis response was completely attenuated in rats treated with captopril. These results indicate that angiotensin II is a powerful modulator of the pressure-natriuresis response. In addition, it has been suggested that prostaglandins are also capable of modulating the response only in the presence of the renin-angiotensin system. However, neither angiotensin nor prostaglandins appears to be essential for the basic pressure-natriuresis phenomenon since the pressure-natriuresis response can occur during blockade of both the renin-angiotensin and prostaglandin systems.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II↗
PubMed1989

Monoclonal antibody that binds to both the prenatal and postnatal astroglia in rodent cerebellum.

A monoclonal antibody (MAb), generated by immunizing mice with homogenized guinea pig cerebellum, labeled cerebellar astroglia including perikarya, radial fibers and veil-like processes in adult rats, mice and guinea pigs. Cell bodies and processes of the immature radial glia in the ventricular neuroepithelium of fetal mice cerebellum were definitely stained by the MAb on the 14th day of gestation. The astroglial components continued to show selective immunoreactivity to the MAb after the 14th day of gestation.

Animals↗
PubMed1989

Meige's syndrome during long-term neuroleptic treatment.

Two patients developed difficulties in eyelid opening following long-term neuroleptic treatment of more than 6-8 years. Tardive dyskinesia and dystonia apart from the face were not found in either case. The symptoms fluctuated in their severities on a daily basis and were easily aggravated by various stimuli, e.g., stress, walking, reading and watching television. Electromyographic studies of their faces clearly indicated that the symptoms resulted from spontaneous blepharospasm and were analogous to idiopathic Meige's syndrome. Therefore, the patients' difficulties in opening their eyes were considered to be the so-called drug-induced Meige's syndrome and/or facial tardive dystonia. It must be stressed that this syndrome is extremely distressing to patients and is a severe complication accompanying a long-term neuroleptic treatment.

Adult↗
PubMed1989

Annular lesion of the lung in sarcoidosis.

A 20 year old man presented with eight thin walled, ring shaped shadows, 1-3 cm in diameter, on a chest radiograph. Pulmonary sarcoidosis was diagnosed on the basis of histopathological examination of a cervical lymph node, transbronchial lung biopsy, and increased activity of angiotensin converting enzyme and lysozyme in serum. The lesions disappeared within six months of his starting corticosteroid treatment.

Adult↗
PubMed1989

[Etiological study of relationship between impacted permanent teeth and malocclusion].

This investigation was undertaken to determine the causes of impacted permanent teeth and whether they have any influence on dentition, occlusion and skeletal patterns. The materials used were dental X-rays, occlusal dental X-rays, panoramic radiograms and cephalograms and dental casts of 194 cases (51 males and 143 females) which revealed impacted permanent teeth among 3979 cases (1215 males and 2764 females) from 1964 to 1985 in the Department of Orthodontics, School of Dentistry, Aichi-Gakuin University. The results obtained were as follows: 1. The incidence of impacted permanent teeth in these samples was 4.9% of the entire number of orthodontic patients. There was no significant difference between sexes. 2. The incidence according to the number of impacted permanent teeth was as follows: one impacted tooth, 74.8%; two impacted teeth; 21.1%, three impacted teeth; 3.6%, four impacted teeth; 0.5%. The incidence of two symmetrically impacted teeth was 61.5%. 3. As to the type of impacted teeth, the frequency of maxillary central incisors was the largest (33.7%), followed by 3 (25.0%), 5 (22.2%), 5 (11.9%), 2 (4.4%), 3 (1.2%), 4 (0.8%), 4 (0.4%), and 7 (0.4%). But no impacted teeth were found in the regions of 1, 2, 6, 6, 7 and 7. 4. As to impacted teeth and the type of malocclusion, the spaced arch in the anterior region had impacted teeth most frequently followed by crowding, open bite and lateral cross bite. Malocclusions with the smallest incidence were cross bite and upper protrusion. The spaced arch had a higher incidence of impacted teeth than bimaxillary protrusion. In the posterior region (impacted molar teeth), the lateral cross bite, spaced arch, and upper protrusion had impacted molars most frequently, crowding was second and cross bite had the least. 5. In the direction of long axis, the impacted tooth with a horizontal direction was found most frequently (35.2%), followed in the order of frequency by inverse direction (32.7%), labial or mesial tipping (22.0%), lingual or distal tipping (5.7%), and right-angled (4.4%). Moreover, the inverse maxillary central incisor and mesially tipped maxillary canine were found most frequently. The frequency of maxillary central incisors with crooked roots was 64.7%, which was higher than that of maxillary canines (19.0%). 6. Lack of space is the most frequently found cause of impacted teeth, and in the anterior region this was the main cause of canine impacted teeth. Eruption impediment by supernumerary teeth and trauma were found to be characteristic causes of anterior impacted teeth.

Adult↗