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T Kameyama

Publications and source records attributed to T Kameyama.

At least 19 recordsLinked to original sources
PubMed1995

Effects of dynorphin A-(1-13) on carbon monoxide-induced delayed amnesia in mice studied in a step-down type passive avoidance task.

The effects of dynorphin A-(1-13) on carbon monoxide (CO)-induced amnesia in mice were investigated using a step-down type passive avoidance task. Memory deficiency occurred in mice when training commenced 7 days after CO exposure although it was not produced 1 day after CO exposure. The median step-down latency in the retention test of the CO-exposed group was significantly shorter than that of the control group. Administration of dynorphin A-(1-13) (1.5 nmol/mouse i.c.v.) 15 min before the first training session prolonged the step-down latency in the CO-exposed group. Dynorphin A-(1-13) administered immediately after the first training session or administered 15 min before the retention test also prolonged the step-down latency in the CO-exposed group. To determine whether this effect of dynorphin A-(1-13) was mediated via kappa-opioid receptors, we attempted to block its action using a kappa-opioid receptor antagonist (nor-binaltorphimine). Nor-binaltorphimine (5.44 nmol/mouse i.c.v.) blocked the effect of dynorphin A-(1-13) on delayed amnesia. However, dynorphin A-(1-13) (0.5, 1.5 and 5.0 nmol/mouse) did not facilitate the acquisition of memory in normal mice. These results suggest that dynorphin A-(1-13) modulates the kappa-opioid receptor-mediated opioid neuronal system, and that it ameliorates the disruptive effect of CO on acquisition, consolidation and/or recall of memory.

Amnesia↗
PubMed1995

kappa-Opioid receptor agonists improve pirenzepine-induced disturbance of spontaneous alternation performance in the mouse.

We investigated the effects of kappa-opioid receptor agonists such as dynorphin A-(1-13) and U-50,488H on the muscarinic M1-selective receptor antagonist pirenzepine (3 micrograms, i.c.v.)-induced impairment of spontaneous alternation performance in the mouse. Although dynorphin A-(1-13)(1-5.6 micrograms, i.c.v.) or U-50,488H ((+/-)trans-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)-cyclohexyl]- benzeneacetamide, methanesulfonate hydrate) (0.1-1 mg/kg, i.p.) alone did not influence either spontaneous alternation performance or total arm entries, pirenzepine (3 micrograms, i.c.v.) impaired spontaneous alternation performance without producing any significant change in total arm entries. In contrast, dynorphin A-(1-13) (3 and 5.6 micrograms, i.c.v.) and U-50,488H (0.3 and 1 mg/kg, i.p.) ameliorated the pirenzepine (3 micrograms, i.c.v.)-induced impairment of spontaneous alternation performance. The ameliorating effects of dynorphin A-(1-13)(3 micrograms, i.c.v.) and U-50,488H (0.3 mg/kg, i.p.) were almost completely reversed by pretreatment with nor-binaltorphimine (4 micrograms, i.c.v.), a kappa-opioid receptor antagonist. These results suggest that the stimulation of kappa-opioid receptors improves memory dysfunctions resulting from the blockade of muscarinic M1 receptors.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1995

Translocation of activated Rho from the cytoplasm to membrane ruffling area, cell-cell adhesion sites and cleavage furrows.

Rho small GTP-binding protein regulates various cell functions, such as formation of stress fibers and focal adhesions, cell motility, membrane ruffling, cytokinesis and smooth muscle contraction in mammalian cells and bud formation in the yeast Saccharomyces cerevisiae. As to the functioning sites of Rho in Saccharomyces cerevisiae, we have recently shown that RHO1 protein, a homologue of mammalian RhoA, is concentrated to the growth region of the cells where cortical actin patches are clustered. However, in mammalian cells, the functioning sites of Rho have not yet been studied. In the present study, MDCK cell lines stably expressing myc-tagged RhoA (myc-RhoA) were prepared and localization of myc-RhoA was first immunohistochemically examined using an anti-myc antibody. In the resting cells, almost all of myc-RhoA was observed in the cytosol. When the cells were stimulated with phorbol ester or hepatocyte growth factor, membrane rufflings were induced and myc-RhoA was translocated to the membrane ruffling area. Moreover, myc-RhoA was translocated from the cytosol to the cell-cell adhesion sites when the cells were transferred from a low to normal Ca2+ medium. RhoA was also concentrated to the cleavage furrows during cytokinesis in Swiss 3T3 cells. Translocation of myc-RhoA to the membrane ruffling area was inhibited by prior microinjection into the cells of Rho GDI, a negative regulator of Rho which inhibits activation of Rho, or of C3, an exoenzyme of Clostridium botulinum which ADP-ribosylates Rho and inhibits its functions, indicating that both activation and functioning of Rho are essential for the translocation of Rho. The ERM (Ezrin, Radixin, Moesin) family members were colocalized with RhoA at all of these sites. However, RhoA was not apparently observed at the focal adhesion plaque where vinculin was localized. These results suggest that at least one of the functioning sites of Rho is the ERM family-controlled actin filament/plasma membrane association sites.

3T3 Cells↗
PubMed1995

Substance P markedly ameliorates scopolamine-induced impairment of spontaneous alternation performance in the mouse.

We investigated the effects of intracerebroventricular injection of substance P (SP) on the scopolamine (1 mg/kg)-induced impairment of spontaneous alternation performance in the mouse. SP (0.001-3 micrograms) alone did not influence either spontaneous alternation performance or total arm entries. Scopolamine (1 mg/kg) impaired spontaneous alternation performance accompanied by an increment in total arm entries. In contrast, SP (0.01-1 micrograms) significantly improved the scopolamine (1 mg/kg)-induced impairment of spontaneous alternation performance without influencing the scopolamine (1 mg/kg)-induced increase in total arm entries. The effects of SP (0.1 micrograms) on the scopolamine (1 mg/kg)-induced impairment of spontaneous alternation performance were almost completely reversed by pretreatment with WIN 62577 (1 mg/kg), a tachykinin NK-1 receptor antagonist. These results suggest that SP improves the scopolamine-induced impairment of spontaneous alternation performance through the mediation of tachykinin NK-1 receptors.

Androstenes↗
PubMed1995

Dynorphin A-(1-13) potently improves scopolamine-induced impairment of passive avoidance response in mice.

The effects of intracerebroventricular administration of dynorphin A-(1-13) on scopolamine-induced amnesia were investigated in mice by using a step-down type passive avoidance task. The pre- or post-training, or pre-retention administration of dynorphin A-(1-13)(0.3-10 micrograms) alone failed to affect step-down latency of the passive avoidance response, while scopolamine (1 mg/kg) significantly shortened step-down latency. Dynorphin A-(1-13)(1 microgram) given 15 min before training and retention tests but not immediately after training significantly improved the scopolamine (1 mg/kg)-induced shortening of step-down latency of the passive avoidance response, indicating antiamnesic effects of dynorphin A-(1-13) (1 microgram). A lower dose (1 mg/kg) of the kappa-opioid receptor antagonist, (-)-(1R,5R,9R)-5,9-diethyl-2-(3-furyl-methyl)- 2'-hydroxy-6,7-benzomorphan, reversed the anti-amnesic effects of dynorphin A-(1-13) (1 microgram). These results suggest that the antiamnesic effects of dynorphin A-(1-13) depend on the timing of drug treatments.

Amnesia↗
PubMed1995

Activation of both dopamine D1 and D2 receptors necessary for amelioration of conditioned fear stress.

Mice exhibited a marked suppression of motility when they were re-placed in the same environment in which they had previously received an electric footshock. This psychological stress-induced motor suppression, known as conditioned fear stress, was dose dependently attenuated by apomorphine, a non-selective dopamine receptor agonist. Combined treatment with the dopamine D1 receptor agonist, SKF 38393 (2,3,4,5-tetrahydro-7,8-dihydroxy-1-phenyl-1-H-3-benzazepine), and the dopamine D2 receptor agonist, quinpirole, also synergistically attenuated the conditioned fear stress although, alone, neither SKF 38393 nor quinpirole did so at the doses used. The effects of apomorphine and of the coadministration of SKF 38393 and quinpirole on the conditioned fear stress were completely blocked by the dopamine D1 receptor antagonist, SCH 23390 (R-(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H- 3-benzazepine), and by the dopamine D2 receptor antagonist, (-)-sulpiride. These results suggest that a dysfunction in the dopaminergic neuronal system is responsible for the conditioned fear stress, and that the activation of both dopamine D1 and D2 receptors is necessary to attenuate this stress-induced motor suppression.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1995

Effects of centrally administered neuropeptides on discriminative stimulus properties of cocaine in the rat.

The present study was designed to investigate the effects of centrally administered neuropeptides on the discriminative stimulus properties of cocaine in the rat. Rats were trained to discriminate 10.0 mg/kg of cocaine from vehicle in a shock avoidance paradigm. The mu-selective opioid agonist [D-Ala2,NMePhe4,Gly-ol]enkephalin (DAMGO) (0.03-0.3 microgram, ICV) or the kappa-selective opioid agonist dynorphin A-(1-13) (1.0-10.0 micrograms, ICV) did not generalize to cocaine cue, although the delta-selective opioid agonist [D-Pen2,L-Pen5]enkephalin (DPLPE) (10.0 micrograms, ICV) reportedly generalizes to it through the mediation of delta-opioid receptors. Thyrotropin-releasing hormone (10.0-56.0 micrograms, ICV), somatostatin (0.3-3.0 micrograms, ICV), substance P (3.0-17.5 micrograms, ICV), or neurotensin (3.0-17.5 micrograms, ICV) did not produce any stimulus effects in common with cocaine. It appears that neuropeptides other than the delta-selective opioid do not play a major role in the discriminative stimulus properties of cocaine.

Animals↗
PubMed1995

Expression of matrix metalloproteinase-3 in stage I and II squamous cell carcinoma of the oral cavity.

PURPOSE: The object of this study was to evaluate the significance of matrix metalloproteinase-3 (MMP-3) in tumor invasion and metastasis of early squamous cell carcinoma (SCC) of the oral cavity. MATERIALS AND METHODS: Surgical specimens from 65 patients with stage I and II SCC of the oral cavity were the subjects of this study. Tissue specimens were fixed in formalin and embedded in paraffin, and the sections were stained with monospecific antibodies against human MMP-3 by the avidin-biotin-peroxidase complex method. RESULTS: Of the 65 patients, 30 (46.2%) tested positive for MMP-3. Immunoreactivity revealed the expression of MMP-3 to be in the small cancer nests in the advancing front of invasion, but not in normal oral epithelium. MMP-3 expression was positively correlated with tumor size, depth of tumor invasion, diffuse invasive mode, and the high incidence of lymph node metastasis. CONCLUSION: MMP-3-containing tumors will invade adjacent normal tissues more aggressively, including lymphatic and blood vessels. Therefore, the examination of MMP-3 expression in biopsy specimens should provide information useful in predicting the malignant potential of early SCC of the oral cavity.

Adult↗
PubMed1995

Comparison of screw placement patterns on the rigidity of the sagittal split ramus osteotomy: technical note.

Various screw placement patterns have been described for fixation of the sagittal split ramus osteotomy. This study is a comparative evaluation of 3 different screw placement patterns on the rigidity of the sagittal split ramus osteotomy. Twenty cadaver mandibles were used to compare the load strength of triangular pattern, oblique linear pattern versus linear pattern. Internal fixation with screws placed in a triangular pattern were significantly more rigid than those fixed with screws placed in the other patterns. Also, internal fixation with an oblique linear pattern was more rigid than that with a linear pattern.

Bone Screws↗
PubMed1995

Tonsillar lipoma: a case report.

Benign tumours of the tonsils are rare. Only a few cases of tonsillar lipoma have been previously reported. The case of a pedunculated polypoid lipoma of the palatine tonsil in a 44-year-old Japanese woman is presented. The 'polyp' was excised and an histopathological examination was carried out. The 'polyp' contained dilated lymphatics in the dense fibrous connective tissue beneath the overlying mucosal epithelium and below the mature fat tissue with intervening strands of fibrous tissue.

Adult↗
PubMed1995

Spinal cord morphology and pathology in ossification of the posterior longitudinal ligament.

We analysed nine autopsy cases of ossification of the posterior longitudinal ligament (OPLL) to elucidate the relationship between morphology and pathology of the spinal cord. The cross-sectional shape of the spinal cord at the most severely affected segment was classified into two categories: boomerang (convex lateral surfaces and concave anterior surface) and triangular (angular lateral surfaces and flat anterior surface). In the cases with a boomerang shape, even when the compression was severe, major pathological changes were restricted to the grey matter and the white matter was relatively well preserved. No secondary descending degeneration of the lateral columns was seen, and ascending degeneration of the posterior column was restricted to the fasciculus cuneatus whose fibres were derived from the affected segments. In the cases with a triangular shape, pathological changes were more severe, both white matter and grey matter were involved, and only the anterior columns were free of pathological changes. There were severe pathological changes over more than one segment, and both descending degeneration of the lateral pyramidal tracts and ascending degeneration of the posterior column, including the fasciculus gracilis, were observed. The transverse area of the spinal cord was > 60% of normal in most of the cases with a boomerang shape, but it was reduced to < 60% of normal in more than one segment in the cases with a triangular shape. The compression ratio of the spinal cord (sagittal diameter/transverse diameter x 100%) was not related to pathological changes. In conclusion, a triangular-shaped spinal cord with transverse area of < 60% of normal in more than one segment appeared to be associated with severe and irreversible pathological changes in cases of OPLL.

Adult↗
PubMed1995

Prominent uptake of Tl-201 by duodenal leiomyosarcoma after exercise myocardial perfusion study.

Thallium-201 SPECT performed preoperatively for the evaluation of myocardial ischemia in a 72-year-old man with duodenal leiomyosarcoma demonstrated prominent focal uptake in the abdomen. Comparing a transaxial slice of SPECT through the abdominal uptake to the CT scan, the uptake was confirmed to be corresponding to the tumor. The tumor was delineated clearly, in good contrast to the surrounding normal intestine, which showed far less Tl-201 uptake than the tumor. In the delayed SPECT performed 3 hours after injection, although the intestinal activity became perceptible, the tumor still could be differentiated from the surrounding normal intestine. In this case, the exercise might be attributable to the initial low Tl-201 uptake by the normal intestine, which might otherwise have been an obstacle to Tl-201 scintigraphy for abdominal tumor detection. This case suggests the use of exercise for avoiding unfavorable intestinal activity, and the possibility of Tl-201 SPECT for abdominal tumor imaging.

Aged↗
PubMed1995

Failure of IgG production due to a defect in the opening of the chromatin structure of I gamma 1 region in a patient with IgG and IgA deficiency.

Patients with common variable immunodeficiency (CVID) display reduced levels of two or all three of the major immunoglobulin isotypes, and the deficiency is characterized by failure of B cells to differentiate into plasma cells in many cases. A patient (14 years old, female) showed normal serum IgM levels and low serum IgG and IgA levels, including low levels of all IgG subclasses. Northern blot analysis suggested that the patient's B cells may be defective at the immunoglobulin heavy chain isotype switch. The germ-line C gamma 1 transcript was amplified from cDNA of healthy controls by the addition of recombinant IL-2 (rIL-2) to pokeweed mitogen-stimulated peripheral mononuclear cells or Staphylococcus aureus Cowan I (SAC)-stimulated IgM-producing lymphoblastoid cell lines (LCL) transformed by Epstein-Barr virus, while it was not amplified from cDNA of the patient. In the I gamma 1 region of LCL cultured with SAC plus rIL-2, the inner cytosine in the 5' C-C-G-G 3' sequence nearest the 3' site of the I gamma 1 region, at least, was not completely unmethylated in the patient. Moreover, the DNase I hypersensitive site was not induced in the patient's LCL by SAC plus rIL-2. These results indicate that the defects of the immunoglobulin heavy chain isotype switch in the patient's B cells are due to failure in the synthesis of germ-line C gamma transcripts, and this may be caused by defects in opening of the chromatin structures of specific switch regions.

Adolescent↗
PubMed1995

High prevalence of hepatitis C virus antibody and RNA in patients with oral cancer.

We have investigated the correlation between the prevalence of hepatitis C virus (HCV), which is detectable in saliva, and oral cancer and other digestive tract cancers in the Northern Kyushu region of Japan. Anti-HCV antibodies were detected in sera from 24 of the 100 patients with oral cancer (24%, p < 0.05 vs the control group, p < 0.01 vs the stomach cancer group), in 11 of 104 patients with non-malignant diseases receiving dental treatment (the control group, 10.6%), and in 12 of 113 patients with stomach cancer (10.6%). HCV-RNA was detected in sera from 17 of 100 oral cancer patients (17%, p < 0.05 vs the control group) and 4 of 104 patients of the control group (3.9%). These results indicate a high prevalence of HCV infection in oral cancer patients, which warrants a systematic study of etiological associations between oral cancer and HCV.

Adolescent↗
PubMed1995

[Neuroimaging and pathology of the spinal cord in compressive cervical myelopathy].

Magnetic resonance imaging (MRI) has enabled us to see the spinal intramedullary pathology as differences in signal intensity. Intramedullary high intensity lesions were observed on T2-weighted MRI in patients with cervical spondylotic myelopathy (20.0%) and ossification of the posterior longitudinal ligament (OPLL) of the cervical spine (25.7%). The frequency of this findings was proportional to the clinical severity of myelopathy and degree of spinal cord compression. The pathophysiological basis of such signal abnormality was presumed to vary from acute edema to chronic myelomalacia. The intramedullary lesion on MRI is considered to be the main site of lesion responsible for the neurological symptom because of a good correlation between the neurological level and high intensity level. We found from nine autopsy cases of OPLL that there are distinct differences in severity and extent of pathological changes between the spinal cord with a boomerang-shaped cross-section and that with a triangular-shaped cross-section. In the boomerang-shaped cases, major pathological changes were restricted to the gray matter and the white matter was relatively well preserved. Secondary wallerian degeneration was restricted to the fasciclus cuneatus the fibers of which were derived from the affected segments. In the cases of a triangular shape, pathological changes were more severe, both white and gray matter were involved. There were severe pathological changes over more than one segment, and both descending degeneration of the lateral pyramidal tracts and ascending degeneration of the posterior column, including the fasciclus gracilis, were observed. In conclusion, it is clinically very important to understand the pathological basis of the compressed spinal cord on neuroimages.

Cervical Vertebrae↗
PubMed1995

[Mitral and aortic annular enlargement for small mitral annulus after mitral annuloplasty].

Mitral and Aortic valve rings were enlarged in a 70-year-old female with tiny mitral annulus after mitral annuloplasty before. She had undergone aortic valve replacement with No. 21 SJM valve and Kay's annuloplasty 10 years previously. The reoperation was needed because of mitral stenosis and tricuspid regurgitation. We applied the Manouguian technique for the enlargement of the mitral annulus because it was too small to implant a prosthetic valve, even though the Aortic prosthetic valve was functioning well. As too tight a mitral annuloplasty may make the possibility of mitral stenosis real, we should make the annulus remain wide enough.

Aged↗