Biomedical subjects

Y Satoh

Publications and source records attributed to Y Satoh.

At least 163 records · Page 9Linked to original sources

PubMed1998

Age-related changes in transiently evoked otoacoustic emissions and distortion product otoacoustic emissions in normal-hearing ears.

Age-related changes in transiently evoked otoacoustic emissions (TEOAEs) and distortion product otoacoustic emissions (DPOAEs) were evaluated in normal-hearing ears. The TEOAE was elicited by a non-linear click with a stimulus level of 82 +/- 1 dB SPL using ILO 88 in 251 normal-hearing ears. The DPOAE at the frequency of 2f1-f2 was measured with stimulus levels of 70 dB SPL (f1) and 60 dB SPL (f2) and with an f2/f1 ratio of 1.2 using ILO 92 in 64 normal-hearing ears. The results obtained showed that TEOAE and DPOAE were decreased with increasing age. Moreover, the same pattern of gradual decrease in TEOAE and in DPOAE suggests the possibility of the same generating mechanism associated with outer hair cells (OHCs).

Acoustic Stimulation↗

PubMed1998

Individual growth in Class III malocclusions and its relationship to the chin cap effects.

Individual growth characteristics of the maxilla and the mandible in Class III malocclusions were investigated in terms of growth amount, growth direction, and timing of growth; chin cap effects were considered in the context of growth characteristics of the jaws. Longitudinal cephalograms of six untreated Japanese Class III subjects were used for the analysis of jaw growth from 8 to 14 years of age. The facial patterns were classified into the five groups with different effects of therapy by discriminant functions derived from our previous chin cap study. The results obtained were as follows: (1) Among the six subjects, inhibition of maxillary forward growth was found in four subjects at ages before the maximum pubertal growth in body height occurred, resulting from occlusal interference of anterior cross bite. The growth potential of the jaws appeared genetically normal, and the facial patterns were classified into groups in which chin caps have been found to be effective to some extent. (2) A subject with growth characteristics of strong mandibular downward growth was classified in a group showing backward growth of the mandible by chin caps. (3) One of the remaining sample showing the strongest mandibular forward growth was classified in a group where chin caps are not effective. (4) It was concluded that effects of chin cap therapy are closely related to growth characteristics of the mandible in Class III treatment.

Adolescent↗

PubMed1998

Role of the carboxy-terminal region of the GluR epsilon2 subunit in synaptic localization of the NMDA receptor channel.

The synaptic localization of the N-methyl-D-aspartate (NMDA) type glutamate receptor (GluR) channel is a prerequisite for synaptic plasticity in the brain. We generated mutant mice carrying the carboxy-terminal truncated GluR epsilon2 subunit of the NMDA receptor channel. The mutant mice died neonatally and failed to form barrelette structures in the brainstem. The mutation greatly decreased the NMDA receptor-mediated component of hippocampal excitatory postsynaptic potentials and punctate immunofluorescent labelings of GluR epsilon2 protein in the neuropil regions, while GluR epsilon2 protein expression was comparable. Immunostaining of cultured cerebral neurons showed the reduced punctate staining of the truncated GluR epsilon2 protein at synapses. These results suggest that the carboxy-terminal region of the GluRepsilon2 subunit is important for efficient clustering and synaptic localization of the NMDA receptor channel.

Afferent Pathways↗

PubMed1998

Granulocyte colony-stimulating factor (G-CSF) dependent hematopoiesis with monosomy 7 in a patient with severe aplastic anemia after ATG/CsA/G-CSF combined therapy.

We report a case of secondary myelodysplastic syndrome (MDS) with monosomy 7, which evolved from severe aplastic anemia (SAA) after long-term use of granulocyte colony-stimulating factor (G-CSF). A 36 year old female was admitted for detailed examination and treatment of pancytopenia. SAA was diagnosed based on hypoplastic bone marrow and a normal chromosome study. She was treated with anti-thymocyte globulin (ATG), ciclosporin A (CsA) and G-CSF, which resulted in gradual improvement of not only the myeloid but also the erythroid-megakaryocyte series. However, bone marrow dysplasia with monosomy 7 was observed after 7 months of a combination therapy of immunosuppressant and G-CSF, which prompted the discontinuation of G-CSF administration. Thereafter, bone marrow hypoplasia gradually progressed, resulting in a second aplastic crisis. During this process, the proportion of marrow cells showing monosomy 7 decreased, and the proportion with normal karyotype increased. Re-administration of G-CSF induced a trilineage, though dysplastic, hematological response; but the monosomy 7 positive population increased again. These observations indicated the presence of G-CSF dependent hematopoiesis associated with monosomy 7 in this patient. Although many G-CSF related MDS/AML cases with this leukemia-specific abnormal karyotype have been reported with emphasis on the harmful effects of G-CSF, G-CSF was useful even after the appearance of monosomy 7 as a means of avoiding life-threatening infection in this patient.

Adult↗

PubMed1998

Beta-decay half-lives and level ordering of 102m,gRh.

Beta-decay half-lives of the ground state and an isomer of 102Rh have been determined 207.3(17) d and 3,742(10) y, respectively, by gamma-ray decay curves following each beta-decay. It has been found that a state (2-) which has a shorter half-life (207.3 d) is the ground state from the result that the half-life of the 41.9 keV isomeric gamma-transition was equal to 3.742 y. It has also been confirmed that the 41.9 keV transition is certainly an isomeric transition with X-gamma coincidence measurement.

Beta Particles↗

PubMed1998

Membrane perturbation by the neurotoxic Alzheimer amyloid fragment beta 25-35 requires aggregation and beta-sheet formation.

The beta-amyloid peptide (beta AP) is a major proteinaceous component of senile plaques and cerebrovascular amyloid deposits found in the brain of patients with Alzheimer's disease. beta AP is reported to be neurotoxic only when it forms beta-sheet structure and aggregates. In the present study, we report that the neurotoxic core of beta AP, beta AP-25-35 (beta 25-35), perturbs liposome membranes, induces membrane current, and exhibits hemolytic activity only in a buffer condition where the peptide forms beta-sheet structure and spontaneously aggregates. In contrast, beta 25-35 in its monomeric random coil structure does not perturb lipid membranes significantly, and exhibits no hemolytic activity. Also, the membrane current was inhibited by Congo Red. The ability of beta 25-35 to interact with membranes highly correlates with its neurotoxicity reported previously. These results suggest that membrane perturbation by aggregated beta 25-35 constitutes the molecular basis of the peptide's neurotoxicity.

Amyloid beta-Peptides↗

PubMed1998

Comparative toxic effects of iobitridol and iohexol on the kidney.

RATIONALE AND OBJECTIVES: The authors compare the toxic effects of iobitridol and iohexol, which are nonionic contrast media with equivalent osmolalities and viscosities on the kidney. METHODS: In a rat acute renal failure (ARF) model, iobitridol or iohexol (both at the dose of 2.87 g I/kg) were injected to rats after pretreatment with indomethacin and N omega-nitro-L-arginin methyl ester. The effects on histopathology, creatinine clearance, and urinary N-acethyl-beta-D-glucosaminidase (NAG) activity were assessed. In a rat renal slice system, the slices were exposed to iobitridol or iohexol (both at the concentration range of 17.5-70 mg iodine/mL) for 60 min. The accumulation of para-aminohippuric acid (PAH), an organic anion, and the intracellular potassium content as the indicators of renal tubular injury were measured to assess the direct effects of iobitridol and iohexol on renal tubules. RESULTS: In the ARF model, no significant difference was detected between the effects of iobitridol and those of iohexol on the creatinine clearance and urinary NAG activity 24 hours after the injection. However, iobitridol produced a lower degree and incidence of renal tubular injury of renal proximal tubules (P < 0.001) and distal tubules (P < 0.05) compared with iohexol. In the rat renal slice system, the iobitridol treatment had significantly less effect on the PAH accumulation compared with iohexol (P < 0.001). There were no changes in the intracellular potassium content. CONCLUSIONS: These findings suggest that iobitridol has significantly less toxic effects on the kidney compared with iohexol under the condition of our experiment.

Analysis of Variance↗

PubMed1998

Augmentation of the inhibitory effect of FK480, a CCK-A receptor antagonist, on pancreatic exocrine secretion by achlorhydria.

The effect of intraluminal acid and cholecystokinin (CCK) receptor blockade on the pancreatic secretory response was examined in rats. Blockade of gastric acid secretion by YM022 (CCK-B receptor antagonist) or famotidine (histamine-2 receptor antagonist) resulted in a significant suppression of casein-stimulated pancreatic exocrine secretion as determined by juice volume and amylase secretion. Ligation of the gastric pylorus, which leads to complete prevention of gastric acid from entering the duodenum, also suppressed pancreatic exocrine secretion. FK480 (CCK-A receptor antagonist) inhibited pancreatic exocrine secretion dose dependently at doses of 0.01-1.0 mg/kg. When submaximal doses of FK480 and YM022 were treated concomitantly, pancreatic exocrine secretion was inhibited more profoundly than when treated solely. Hydrochloric acid (HCl; 0.05 N), injected into the duodenum, stimulated pancreatic exocrine secretion to a level comparable to that exhibited by intraduodenal casein. This effect of HCl was inhibited by FK480 (1.0 mg/kg) but not by YM022 (1.0 mg/kg). These findings suggest that inhibition of gastric acid secretion leads to the suppression of pancreatic exocrine secretion through mechanisms mediated by CCK-A receptors.

Achlorhydria↗

PubMed1998

Effect of FK480, a CCK-A receptor antagonist, on spontaneously developed chronic pancreatitis in WBN/Kob rats.

The effect of FK480, a cholecystokinin-A (CCK-A) selective receptor antagonist, on spontaneously developed chronic pancreatitis was examined in WBN/Kob rats. Animals at age 18 weeks (18w-Control) already had the histologic appearance of chronic pancreatitis as indicated by inflammatory cell infiltration and fibrotic degeneration with interstitial edema. Rats treated with vehicle from 18 to 26 weeks of age (26w-Control) showed further development of pancreatitis as characterized by more extensive appearance of inflammatory cell infiltration and fibrotic changes, with the pancreatic weight significantly decreased. Serum amylase levels of 26w-Control animals were slightly decreased compared with those of 18w-Control animals, although the difference was not statistically significant. When rats were treated orally with 1, 10, and 100 microg/kg FK480 from 18 to 26 weeks of age, the decrease in serum amylase levels recovered dose dependently compared with 26w-Control, and the level in animals treated with 100 microg/kg FK480 was almost the same as that in 18w-Control rats. Histologic examinations revealed that the appearance of the pancreas of animals treated with FK480 was slightly improved with respect to inflammatory cell infiltration and edematous changes at the highest dose examined, although the difference was not statistically significant. Although blockade of the CCK-A receptor could be considered to exacerbate chronic pancreatitis due to possible inhibition of the trophic action of CCK, our results suggest that CCK-A receptor antagonists may not be detrimental to chronic pancreatitis.

Amylases↗

PubMed1998

Recurrent hepatosplenomegaly and peripheral blood cytopenia, persistent Epstein-Barr virus infection and central nervous system manifestation in a patient with lymphadenopathy and low serum uric acid.

We describe a 27-month-old boy who was first admitted to our hospital on 7 January 1995 with nasal bleeding. From 6 months of age he has had lymphadenopathy, low levels of serum uric acid, increased levels of serum lactate dehydrogenase and hyper gamma-globulinemia. From the age of 18 months he has had persistent Epstein-Barr virus (EBV) infection (target cells; B cells), recurrent episodes of thrombocytopenia, anemia and hepatosplenomegaly. Dysmobility of the left leg and arm from a central nervous system complication during a relapse with pancytopenia on March 1995, was also observed. Relapses of thrombocytopenia with increases of platelet-associated immunoglobulin G and hepatosplenomegaly have been observed approximately every 2 months, and two relapses of pancytopenia were accompanied with weak positivity of Coombs test and low level of haptoglobin. These recurrent episodes were improved with prednisolone. However, now in June 1997 we have not been able to diagnose what underlies the above clinical symptoms, except that the patient has a persistent EBV infection.

Central Nervous System Diseases↗

PubMed1998

Immunohistochemical evidence of the mesothelial histogenesis of a uterine adenomatoid tumor.

We present rare case of a uterine adenomatoid tumor. In order to characterize the diversity of immunoreactive antigens associated with mesothelial differentiation, we immunohistochemically examined the tumor's epithelioid and myofibromatoid components, as well as the biphasic pattern of its adenomatoid changes. Immunostaining of tumor cells was positive for high- and low-molecular-weight cytokeratins and vimentin. Specific immunoreactions with antibodies against desmin, alpha-actin, and the S-100 protein also were observed. The present adenomatoid tumor can be explained in terms of various transformations and typical alterations in mesothelioma cells: (1) the mesothelial cells had differentiated to epithelial and stromal components, concomitant with the presence of predominant reactive foci; (2) intermediate cells expressed different types of cytoskeletal intermediate filament proteins (IMPs); and (3) the patterns of fibromatoid and leiomyoid differentiation resembled those of a benign mesothelioma of the ovarian or oviductal peritoneum. Our immunohistochemical investigations indicated that the present tumor exhibited the histogenesis of a true mesothelioma, an adenomatoid mesothelioma.

Actins↗

PubMed1998

Pretreatment with restriction enzyme or bovine serum albumin for effective PCR amplification of Epstein-Barr virus DNA in DNA extracted from paraffin-embedded gastric carcinoma tissue.

An association between Epstein-Barr virus (EBV) and gastric carcinoma has been studied through the EBV genome present in the carcinoma cells. Recently, we found that EBV DNA in paraffin-embedded gastric carcinoma tissue was detected effectively by PCR after pretreatment of the extracted DNA with a restriction enzyme, BamHI or EcoRI. Here, we show that the PCR amplification was also enhanced by pretreatment of the DNA with other restriction enzymes or with bovine serum albumin and several other proteins. Treatment with these proteins may remove a PCR inhibitor(s) in the DNA samples extracted from the paraffin blocks.

Animals↗

PubMed1998

Mitochondrial deoxyribonucleic acid 3256C-T mutation in a Japanese family with noninsulin-dependent diabetes mellitus.

Accumulating reports indicate a relationship between mitochondrial DNA mutation and impaired glucose-induced insulin secretion leading to a subtype of noninsulin-dependent diabetes mellitus. DNA from a 45-yr-old Japanese woman with noninsulin-dependent diabetes mellitus and muscle atrophy was isolated and studied for mitochondrial DNA mutations. We identified a mitochondrial DNA C-T heteroplasmic mutation at nucleotide position 3256. The mutation was located in the transfer ribonucleic acidLeu in a region conserved in evolution. Eight other members of her family were examined for the mutation. Six of them had the same mutation together with noninsulin-dependent diabetes mellitus, and one teenage boy had the mutation and impaired glucose tolerance. The other family member who did not have this mutation had normal glucose tolerance. The enzyme activity of the mitochondrial oxidative phosphorylation pathway in the muscle of the proband was measured. The enzyme activity was decreased in the proband, especially in complex I. This mutation might be responsible for the abnormal glucose metabolism.

Adolescent↗

PubMed1998

Four new immunosuppressive components, kobiin and kobifuranones A, B, and C, from an ascomycete, Gelasinospora kobi.

A new sesterterpenetriol named kobiin and three new 2-furanones named kobifuranones A, B, and C were isolated from an Ascomycete, Gelasinospora kobi. Kobiin, the main immunosuppressive principle of this fungus, possesses a bicyclic skeleton of five- and fifteen-membered rings. Kobifuranones A, B, and C were supposed to be metabolites formed from a common intermediate biosynthesized through the acetate-malonate pathway. The immunosuppressive activity of kobiin and kobifuranones A, B, and C was evaluated in a system of mouse spleen lymphocytes stimulated to proliferate with concanavalin A and lipopolysaccharide.

Animals↗

PubMed1998

[Signal transduction of serotonin release from enterochromaffin cells in mouse ileal crypts].

Although serotonin (5-HT) release from enterochromaffin (EC) cells is considered to be regulated by multiple receptor-mediated mechanisms, little is known about the signal transduction in EC cells. We investigated the effects of adrenoceptor stimulation on 5-HT release from ileal tissue and intracellular calcium dynamics of epithelial cells in isolated ileal crypts in mice. Ileal tissues placed in organ bath were perfused with a buffered solution. Released 5-HT was measured using HPLC-ECD. Ileal crypts were isolated by collagenase digestion followed by moderate pipetting. Intracellular calcium dynamics were analyzed by digital video-imaging system using fura-2. NE, but not isoprenaline (Iso), induced 5-HT release from mouse ileal tissue. NE-induced 5-HT release was antagonized by yohimbine and rauwolscine, but not by prazosin and bunazosin. NE, but not Iso, also elicited a transient elevation of intracellular calcium in some EC cells. The effect of NE (1 microM) was slightly suppressed by prazosin and bunazosin, but was remarkably suppressed by yohimbine and rauwolscine. UK 14,304 and Clonidine at 10 microM significantly induced an increase in intracellular calcium concentration. NE-induced intracellular calcium dynamics was not significantly affected by timolol, Ro20-1724, rolipram and 8-bromo-cAMP. These results suggest that NE-induced 5-HT release from ileal EC cells is mediated predominantly via alpha 2-, but not beta-adrenoceptors, by a mechanism dependent on elevation of intracellular calcium concentration.

4-(3-Butoxy-4-methoxybenzyl)-2-imidazolidinone↗

PubMed1998

Bilateral coronary ostial stenosis and aortic regurgitation due to syphilitic aortitis.

Coronary ostial stenosis in otherwise normal coronary vessels, is a rare complication of syphilitic aortitis, and most of the cases are found at autopsy. We report here a case in which bilateral coronary ostial stenosis and aortic regurgitation due to syphilitic aortitis was diagnosed; coronary artery bypass graft and aortic valve replacement were then performed. The macroscopic finding and the histopathological examination of the ascending aorta revealed the presence of syphilitic aortitis. It is important to note that syphilis is one of the causes of coronary ostial stenosis in young adults associated with aortic regurgitation.

Adult↗

PubMed1998

Orthodontic treatment of an adult male after bilateral condylectomy of the mandible for injuries sustained in a traffic accident.

In recent years there have been many reports on studies related to the temporomandibular joint (TMJ) in orthodontic treatment, but an adequate system of diagnosis and treatment has yet to be established, and they often cause considerable difficulty clinically. The patient in this case report sustained generalized contusions, a cerebral concussion, a midline fracture of the mandibular corpus, and bilateral fractures of the condylar process of the mandible when he fell asleep while driving a car and collided with a truck. Because non-surgical reduction was impossible, mandibular condylectomy was performed, and when orthodontic treatment was attempted to improve the open bite that persisted as a sequela of the accident, the favorable results were obtained, as described below. 1. The open bite was corrected by the orthodontic treatment, and the impairment that remained as a sequela resolved. 2. The mandibular condyles were removed during surgical reduction, and the mouth opening disturbance, the TMJ pain, and the TMJ noise resolved. The patient was able to go about his everyday life unimpaired, with hardly any awareness of limitation of jaw movement, and this situation remained unchanged even after the orthodontic treatment was performed.

Accidents, Traffic↗

PubMed1998

Circadian blood pressure and heart rate profiles in normotensive patients with mild hyperthyroidism.

We investigated the influence of thyroid hormones on the circadian blood pressure (BP) and heart rate (HR) variations in 12 normotensive subjects and 12 normotensive patients with mild hyperthyroidism. BP and HR were monitored every 30 minutes for 48 h, and electrocardiograms (ECGs) were recorded to measure the RR interval of the ECGs. We analyzed the circadian BP and HR variations, HR variability, and the morning rise in BP and HR. There was no significant difference in the average 24 h BP between groups. HR and pulse pressure were higher in the hyperthyroid group than in the control group. Though the circadian BP pattern was similar in both groups, HR decreased at night in the control group, but not in the hyperthyroid group. Spectrum analysis of the RR interval showed no increase in the high-frequency (HF) component at night in patients with hyperthyroidism. The HR did not show a morning rise in the hyperthyroid group. These findings indicate that the circadian rhythm of HR was not preserved in patients with mild hyperthyroidism. The circadian BP rhythm was similar in normotensive subjects and normotensive patients with mild hyperthyroidism, suggesting that it resulted from factors other than thyroid hormone.

Adult↗