Search PubMed⌕ Search

Biomedical subjects

Y Kataoka

Publications and source records attributed to Y Kataoka.

At least 145 records · Page 8Linked to original sources
PubMed1994

Two distinct pathways are involved in the endothelin-3-evoked dopamine release from rat striatal slices.

We investigated mechanisms mediating endothelin-3-evoked dopamine release from rat striatal slices. Endothelin-3 stimulated dopamine release from the slices in a concentration-dependent manner over a range from 1 to 10 microM. Tetrodotoxin suppressed dopamine release, but left 40% of the release unaffected. Nifedipine, a voltage-gated Ca2+ channel (VGCC) antagonist, significantly inhibited dopamine release in the presence and absence of tetrodotoxin. Endothelin-3-evoked dopamine release was attenuated by D-2-amino-5-phosphnovaleric acid or Mg2+, N-methyl-D-aspartate receptor inhibitors, and this attenuation was not observed in the presence of tetrodotoxin, thereby indicating that the tetrodotoxin-sensitive component of dopamine release was partially mediated by glutamatergic pathways. This view was also supported by findings that endothelin-3 evoked glutamate release and the exogenously applied glutamate stimulated dopamine release. Based on these results, we hypothesize that endothelin-3 produces dopamine release through two distinct mechanisms; one is a direct stimulation of dopaminergic nerve terminals and the other was activation of interneurons which promoted the release of glutamate, resulting in dopamine release.

2-Amino-5-phosphonovalerate↗
PubMed1994

Activation of glutamate receptors in response to membrane depolarization of hair cells isolated from chick cochlea.

1. Experiments were performed to identify the neurotransmitter released from hair cells of chick cochlea. An isolated hair cell was closely apposed to a cultured granule cell of the rat cerebellum, and both cells were whole-cell voltage clamped by utilizing a nystatin perforated patch technique. 2. Depolarization of hair cells to potentials more positive than -20 mV induced currents in the granule cell in a 10 mM Ca2+ extracellular medium. Amplitudes of induced currents were dependent on the membrane potential of granule cells and showed an outward-going rectification. The induced current in granule cells was reversibly suppressed by a local application of 2-amino-5-phosphonovalerate (APV), which indicates that the current was generated through the activation of an NMDA subtype of the glutamate receptor expressed on the granule cell. 3. The current amplitude of the granule cell was dependent on the size of hair cell depolarization. The size of current induced in a granule cell held at +55 mV was progressively increased with hair cell depolarization from -20 to +10 mV. At more positive potentials, the current amplitude was decreased. This voltage dependence was similar to but did not exactly match that of Ca2+ currents in the hair cell. The granule cell current appeared at more positive membrane potentials than the Ca2+ current in hair cells. 4. When intracellular Ca2+ concentration was increased by UV irradiation of the hair cell loaded with a caged Ca2+ compound, nitr-5, the closely apposed granule cell generated an outward current when voltage clamped at +55 mV. 5. These observations (paragraphs 2-4) imply that the most likely neurotransmitter released from the hair cell at its synapse with the afferent nerve terminal is glutamate.

2-Amino-5-phosphonovalerate↗
PubMed1994

Endothelin increased [Ca2+]i in cultured neurones and slices of rat hippocampus.

We reported here the first evidence that endothelin (ET)-1 and ET-3 produced an increase in intracellular Ca2+ concentrations ([Ca2+]1), consisting of a transient and a sustained component, in cultured neurones and in slices of the rat hippocampus. In the neurones, the removal of Ca2+ or the addition of Cd2+ remarkably inhibited the ET-3-evoked sustained but not the transient response. The [Ca2+]i increased by ETs was observed in the dentate gyrus and in the vicinity of CA1 and CA3 pyramidal cell layer in the hippocampus, findings in good accord with regions where the glutamate receptor agonists have an elevated [Ca2+]i. The possible causal link between ETs and the increased [Ca2+]i in the development of hippocampal neuronal death is discussed.

Animals↗
PubMed1994

Endothelin-3 activates a voltage-gated Ca channel via a pertussis toxin sensitive mechanism leading to dopamine release from PC12 cells.

We have investigated the role of endothelin-3 (ET-3) in the stimulus-secretion coupling mechanism in rat pheochromocytoma PC12 cells. ET-3 (10-100 nM) evoked both dopamine (DA) release and an increase in intracellular Ca2+ concentration ([Ca]i). The ET-3-evoked DA release was partially inhibited by pretreatment with pertussis toxin (PTX; 2 ng/ml, 20 h). The release was also attenuated by the voltage-gated Ca channel (VGC) blockers Cd2+ (300 microM) or nicardipine (30 microM) and was completely abolished when external Ca2+ was removed. ET-3-evoked [Ca]i increase was attenuated by the application of these VGC blockers and by pretreatment with PTX, and was abolished by removal of extracellular Ca2+. Removal of external Na+ had no effect on either response. In light of these findings, we conclude that ET-3 evokes both DA release and an increase in [Ca]i by a mechanism which involves the activation of PTX-sensitive VGCs and the resultant influx of Ca2+.

Animals↗
PubMed1994

Case report 858: Postradiation osteosarcoma of the patella.

A case of postradiation osteosarcoma of the patella in a 54-year-old man was presented. The lesion in the patella was diffuse and highly sclerotic, and was partially radiolucent in radiographs. The whole patella was removed by Miyakawa's method. Diagnostic criteria, clinical features, and radiographic findings of postradiation sarcoma were described. The rarity of osteosarcoma of the patella was emphasized.

Bone Neoplasms↗
PubMed1994

Endothelin-3 stimulates inositol 1,4,5-trisphosphate production and Ca2+ influx to produce biphasic dopamine release from rat striatal slices.

1. Real-time monitoring of dopamine (DA) release from rat striatal slices demonstrated that endothelin (ET)-3 (0.1-10 microM) produced a biphasic DA release consisting of transient and sustained components. When extracellular Ca2+ was removed, the sustained but not transient response remarkably decreased. 2. ET-3 (1-10 microM) stimulated an increase in the intracellular Ca2+ concentration ([Ca(2+)]i), which also consisted of two components. The external Ca2+ depletion inhibited primarily the sustained component of the Ca2+ response to ET-3. 3. ET-3 increased inositol 1,4,5-trisphosphate (IP3) concentrations in striatal slices. This response peaked at 10 to 20 sec and returned to the basal level 2 min after stimulation, an event which was in good accord with a prompt and transient phase of both cytosolic Ca2+ activity and DA release evoked by ET-3. 4. Thus, ET-3 produces a transient and a sustained release of DA from striatal slices by stimulating intracellular Ca2+ mobilization via IP3 formation and extracellular Ca2+ influx, respectively.

Animals↗
PubMed1994

Two genomic variations in the E1 region of canine adenovirus type 2 strains.

We amplified the E1 region of canine adenovirus type 2 genomes by the polymerase chain reaction (PCR) and analyzed the PCR products by using eight restriction endonucleases. Restriction patterns of the E1 region cleaved with HaeIII and RsaI revealed two genomic variations among the canine adenovirus type 2 strains. Although the clinical significance of two distinct genotypes among the canine adenovirus type 2 strains is currently unknown, these genomic variations are well conserved among different strains in each genotype and suggest that the Japanese field strains, with reference to the E1 region, are different from the non-Japanese strains examined.

Adenoviruses, Canine↗
PubMed1994

Microglia with an endothelin ETB receptor aggregate in rat hippocampus CA1 subfields following transient forebrain ischemia.

We examined endothelin (ET) receptors in the hippocampus CA1 subfields of stroke-prone spontaneously hypertensive rats subjected to a 10-min bilateral carotid occlusion and reperfusion. When delayed neuronal death had occurred in the pyramidal cell layer at 7 days after transient forebrain ischemia, the quantitative receptor autoradiographic method we used revealed a dramatic increase in number of 125I-ET-1 binding sites in the hippocampus CA1 subfields. The highest number of de novo binding sites appeared in the area corresponding anatomically to the pyramidal cell layer with neuronal death. These binding sites were characteristically the ETB receptor. The de novo 125I-ET-1 binding was mainly present on microglia aggregating with a high density in the damaged pyramidal cell layer. As ET-1- and ET-3-like immunoreactivities were highly expressed within astrocytes in damaged neural tissue, the possibility that microglia with the ETB receptor are activated to participate in the pathophysiology of ischemia-related neural tissue damage by astrocytic ET-1 and ET-3 produced in response to transient forebrain ischemia would have to be considered.

Amino Acid Sequence↗
PubMed1994

GABA receptor function in the parasympathetic ganglia.

The criteria required to establish gamma-aminobutyric acid (GABA) as a neurotransmitter have been fulfilled in the enteric nervous system of the mammalian intestine. In the intestine, GABA-A receptors are located on somato-dendritic regions of the postganglionic cholinergic neurons and mediate the release of acetylcholine (ACh). GABA-B receptors are located on nerve terminals of the cholinergic neurons and mediate inhibition of nerve-stimulated release of ACh. In the urinary bladder, GABA is possibly a noncholinergic, nonadrenergic inhibitory neurotransmitter. Both GABA-A and GABA-B receptors seem to be present in the parasympathetic ganglia and mediate inhibition of ACh release from the cholinergic neurons. Thus, the functional property of GABA-A receptor is different between the intestine and urinary bladder. GABA-A receptors are also located on the GABAergic nerve terminals as an autoreceptor, and mediate inhibition of GABA release both in the intestine and urinary bladder.

Animals↗
PubMed1994

[Unreduced congenital hip dislocation in adults].

Thirty-four cases of unreduced congenital dislocation of the hip were reviewed. The hips were completely dislocated and rode high with the femoral head supported by gluteal muscles, but not by a false acetabulum. The mean Harris hip score was 64 points. Twenty-four patients (80%) had mild or severe low backache, and this was associated with increased lumbar lordosis or functional scoliosis. Seven patients (20%) had valgus malalignment and dysfunction of the knee joint. In older patients over 50 years old, there were many significant problems in the hip, lumbar spine and knee.

Adult↗
PubMed1994

[Pathogenesis of thoracic outlet syndrome: diagnosis with neurography of the brachial plexus].

From 1985 to 1992, the brachial plexus in 130 cases with thoracic outlet syndrome (TOS) was examined by neurography. We found evidence of stretching in patients with severe symptoms who were examined with their arm at their side. We studied the relationship between the evidence we found and the clinical symptoms and signs, to investigate the pathogenesis of TOS. The compression and stretching of the brachial plexus were evaluated visually. The TOS cases were classified into four types: (I) Compression only, (II) Compression > Stretching, (III) Compression < Stretching, and (IV) Stretching only. We confirmed that there were characteristic clinical features for each type of TOS. From these results, both compression and stretching of the brachial plexus were suggested pathogenetic factors of TOS. Conservative treatment using a scapular band was effective for the stretching types III and IV, while surgical treatment was indicated for the compression types I and II.

Adolescent↗
PubMed1993

Distinct cytotoxicity against neuroblastoma cells of peripheral blood and tumor-infiltrating lymphocytes from patients with neuroblastoma.

The cytotoxicity against neuroblastoma cells of IL-2-activated peripheral blood (PBL) and tumor-infiltrating lymphocytes (TIL) was evaluated in seventeen patients with neuroblastoma. Regional lymph node lymphocytes (LNL) were similarly studied in some patients. Three allogeneic neuroblastoma cell lines, LA2D2, LA2B4 and SIFA, established from the different metastases of the same patient were used as targets. Of the three neuroblastoma lines, LA2D2, with low CD56 expression, was the most susceptible to IL-2-activated lymphocytes, while SIFA, with high CD56 expression, was resistant in the greatest degree. LA2B4 showed moderate susceptibility. Although TIL (73.9 +/- 2.1%), LNL (81.0%) and PBL (76.2 +/- 3.1%) revealed similar cytotoxic activity to K562, they demonstrated distinct cytotoxic activities to each neuroblastoma cell line, as follows: against LA2D2: TIL 56.3 +/- 4.2%, LNL 52.1%, PBL 33.6 +/- 4.9% (P < 0.01); against LA2B4: TIL 47.3 +/- 3.3%, LNL 37.8%, PBL 33.7 +/- 4.8% (P < 0.05); against SIFA: TIL 27.0 +/- 6.2%, LNL 20.7%, PBL 13.9 +/- 2.4% (P = 0.056). TIL always showed higher cytotoxic activity against neuroblastoma cells than those of LNL and PBL, whereas LNL were more cytotoxic than PBL. This data showed that TIL from neuroblastoma patients preferentially killed neuroblastoma cells. It was suggested that lymphocytes in the tumor site and regional lymph node could have been sensitized with neuroblastoma-related antigens and exert preferential killing activity against neuroblastoma cells. Phenotypical analysis revealed that TIL had a larger population of CD56+ cells than PBL. Conversely, PBL had a higher population of CD16+ cells than TIL. The cytotoxic activity of TIL significantly decreased by the depletion of CD56+ cells (10.9 +/- 6.2 from 49.9 +/- 5.9% against LA2D2, P < 0.001). These results indicated that CD56+ cells were most responsible for the killing of neuroblastoma cells, and that TIL, with a high proportion of CD56+ cells with strong activity, would be the best source for the immunotherapy of neuroblastoma. Additionally, since neuroblastoma cell lines used in the present study were derived from the different metastases of the same patient, heterogeneity in the susceptibility to lymphocytes might result from the differential expression of tumor-related antigens on these cell lines.

Antigens, Neoplasm↗
PubMed1993

Increased production of endothelins in the hippocampus of stroke-prone spontaneously hypertensive rats following transient forebrain ischemia: histochemical evidence.

1. The effect of transient forebrain ischemia on endothelin-1 (ET-1) and endothelin-3 (ET-3) production in the hippocampus of stroke-prone spontaneously hypertensive rats (SHRSPs) was investigated using immunohistochemical techniques. 2. In SHRSPs subjected to 10-min bilateral carotid occlusion, neuronal degeneration in the CA1 pyramidal cell layer of the hippocampus was detectable at 4 days and remarkable at 7 days after reperfusion. 3. Coinciding with neuronal degeneration, ET-1- and ET-3-like immunoreactivities were intense in the CA1 pyramidal-cell layer, the stratum lacunosum moleculare, and the CA4 subfield of the hippocampus. Almost all of the immunostained cells had morphological characteristics of astrocytes. 4. The possibility that ET has a role in the development of neuronal cell death following transient forebrain ischemia warrants further attention.

Animals↗
PubMed1993

Congenital sarcoma in the terminal ileum histologically resembling clear cell sarcoma of the kidney: a case report with an immunohistochemical study.

We report a case of a newborn female with a rare tumor, a congenital sarcoma, presenting as an abdominal mass. Laparotomy demonstrated the tumor arising from the wall of the terminal ileum. Histologically, the tumor tissue was indistinguishable from clear cell sarcoma of the kidney and was composed of proliferating cells with poorly stained cytoplasm divided into nests or cords by arborizing vasculature. Immunohistochemical staining revealed that the neoplastic cells had a phenotype similar to metanephric blastemal cells of fetal kidney, ie, positive for vimentin and CD24 but negative for cytokeratin and CD9. The results suggest that this congenital tumor may originate from primitive mesenchymal cells phenotypically related to cells present in the fetal kidney.

Diagnosis, Differential↗
PubMed1993

Effects of ketamine on cardiovascular responses mediated by N-methyl-D-aspartate receptor in the rat nucleus tractus solitarius.

BACKGROUND: Ketamine is often administered to patients in whom hemodynamic instability is suspected. This study was designed to investigate the effect and possible site of action of ketamine on baroreflex response in rats. The site focused upon was the N-methyl-D-aspartate (NMDA) receptor of the nucleus tractus solitarius (NTS). METHODS: The effect of ketamine upon the baroreflex response was examined in urethan-anesthetized rats. The baroreflex was elicited by traction of the left carotid artery. Additional studies tested the acute hypotension and effect of ketamine on the hemodynamic response elicited by microinjection of NMDA into the NTS. RESULTS: Upon traction, the mean arterial pressure (MAP) decreased by 28.0 +/- 1.0 (mean +/- SE) mmHg and the heart rate (HR) decreased by 7.5 +/- 0.8 beats/min. Ketamine (9 mg/kg i.v.) attenuated these responses with a resultant decrease in MAP and HR of 3.6 +/- 1.3 mmHg and 1.6 +/- 0.2 beats/min, respectively (P < .01). It also suppressed the NMDA-induced decrease in MAP from 47 +/- 5 to 6 +/- 0.7 mmHg and delayed the decrease in HR. D-2-amino-5-phosphonovalerate, a competitive NMDA antagonist, blocked the NMDA-induced decrease in MAP from 47 +/- 5 to 18 +/- 6 mmHg and delayed the decrease in HR. CONCLUSIONS: These findings support the view that ketamine might attenuate cardiovascular responses such as baroreflex by interacting, at least in part, with the NMDA receptor in the NTS.

Animals↗
PubMed1993

Increase in T cells bearing the gamma/delta receptor associated with lymphoproliferative disease of granular lymphocytes in an infant with intractable diarrhea.

A two-year-old infant with intractable diarrhea and lymphoproliferative disease of granular lymphocytes attributed to a persistent cytomegalovirus infection showed an increase in cells bearing the gamma/delta T-cell receptor (TCR), which accounted for approximately 20% of total peripheral blood lymphocytes and 40% of CD3+ T cells. Of the gamma/delta TCR+ cells, two-thirds were double negative (CD4-/CD8-) and the other one-third CD8 positive. The majority of gamma/delta+ cells were delta TCS 1 positive. The predominance of delta TCS 1 positive cells was also confirmed on biopsy of lymphoid tissues from the colon. After improvement of watery diarrhea and malnutrition following three-month hyperalimentation, the number of gamma/delta TCR+ cells decreased. The patient subsequently died of pneumonia at the age of 2 years and 11 months. A possible site-specific role for the gamma/delta TCR+ cells, particularly delta TCS 1+ cells, in the human intestine is discussed.

Child, Preschool↗