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Biomedical subjects

T Ohmori

Publications and source records attributed to T Ohmori.

At least 55 records · Page 3Linked to original sources
PubMed2000

Effect of eccentric clenching on mandibular deviation in the vicinity of mandibular rest position.

Although the mechanical compression of the temporomandibular joint (TMJ), which could be caused by bruxism, would probably result in a slight change of the occlusal relationship, the effect of clenching in the eccentric mandibular position on the occlusal contact has not yet been clarified. This study aimed to investigate the effect of eccentric clenching on bilateral condylar position and thus to estimate any change of occlusal contact. Before and after voluntary clenching, with one third of the maximal voluntary clenching force, for 3 min at the canine edge-to-edge position, vertical deviation of the bilateral condyles was measured at the 1 mm open mandibular position. This was regulated by the three-dimensional position of the anterior reference point which stands for the incisor point. The mean vertical displacement of the highly deviated side of the condyle was 141+/-55 microm, and the calculated mean displacement of the mandibular first molar region of the highly deviated side was 65+/-27 microm. From the results of this study, it was revealed that the eccentric clenching gave rise to three-dimensional deviation of the mandible even when the mandible was in the vicinity of the rest position.

Adult↗
PubMed2000

Sclerosing encapsulating peritonitis and non-occlusive mesenteric infarction found at autopsy in a man who had undergone continuous ambulatory peritoneal dialysis: a histochemical and immunohistochemical study.

This is a report of a post-mortem histological, histochemical, and immunohistochemical examination of a rare case of sclerosing encapsulating peritonitis (SEP) and non-occlusive mesenteric infarction (NOMI), two serious complications of continuous ambulatory peritoneal dialysis (CAPD), with which a man suffering hepatitis C virus (HCV)-induced liver cirrhosis for 7 years and trauma-induced paraplegia for 50 years had been treated for 1 year. The direct cause of death was encephalopathy caused by extreme hyperammonemia (11 250 microg/dL in serum). The autopsy revealed that the SEP had drastically reduced the length of the small intestine to 210 cm, 180 cm of which presented acute ischemic enteritis with Gram-negative bacterial infection. Histological examination of the SEP revealed that the exterior was composed of normal serosal elastic lamina, but with a cocoon-like appearance remarkably thickened by fibrosis to 3-8 times that of the normal subserosal layer and consisting of spindle cells and blood vessels, with some infiltration of mast cells and lymphocytes. The immunohistochemical examination of the spindle cells revealed few AE1/AE3(+) cells, HHF35(+) cells, and CD34(+) cells, many CD117(+) cells with slight proliferative activity based on MIB-1 positivity (proliferation index <1%), but no CD44(+) cells. It was concluded that either the few CD34(+) and/or the many CD117(+) cells were mesenteric stem cells that had originated from the serosa, proliferated, then differentiated into myofibroblasts or fibroblasts, producing collagen and hyaluronic acid in the matrix, leading to the gradual formation of the SEP, which was induced by the continual irritation of CAPD.

Aged↗
PubMed2000

Rho-mediated phosphorylation of focal adhesion kinase and myosin light chain in human endothelial cells stimulated with sphingosine 1-phosphate, a bioactive lysophospholipid released from activated platelets.

Since sphingosine 1-phosphate (Sph-1-P) is stored in abundant amounts in blood platelets and released extracellularly upon stimulation, it is important to clarify the effects of this bioactive lysophospholipid on vascular endothelial cells from the viewpoint of platelet-endothelial cell interactions. In this study, we investigated the effects of Sph-1-P on the cytoskeletal remodeling of human umbilical vein endothelial cells (HUVECs). Of a focal adhesion kinase (FAK) family of non-receptor protein-tyrosine kinases, HUVECs were found to express FAK, but scarcely proline-rich tyrosine kinase 2. Sph-1-P induced FAK tyrosine phosphorylation, myosin light chain phosphorylation, and the formation of stress fibers in HUVECs. The specific Rho inactivator C3 transferase from Clostridium botulinum abolished all of these cytoskeletal responses induced by Sph-1-P, while pertussis toxin only partly inhibited FAK tyrosine phosphorylation, and hardly affected myosin light chain phosphorylation and stress fiber formation. In contrast, Sph-1-P-induced intracellular Ca(2)(+) mobilization was suppressed by pertussis toxin, but not at all by C3 exoenzyme. Our results suggest that Sph-1-P, a bioactive lipid released from activated platelets, induces endothelial cell cytoskeletal reorganization, mainly through Rho-mediated signaling pathways.

Cytoskeleton↗
PubMed2000

Context determines the type of sensitized behaviour: a brief review and a hypothesis on the role of environment in behavioural sensitization.

Behavioural sensitization to psychostimulants may develop context-dependency in certain circumstances. Animals given a stimulant repeatedly in a test cage but not in other environments may show enhanced drug-induced behaviour in the test cage. Conditioning mechanisms have been claimed to be responsible for these phenomena. However, several recent findings are not properly accounted for by conditioning. In addition, growing evidence supports the hypothesis that behavioural sensitization reflects neural changes induced by repeated exposure to psychostimulants (the pharmacological hypothesis). However, the pharmacological hypothesis itself fails to account for environmental influences. In this paper, we propose a hypothesis on the role of environment that is complementary to the pharmacological hypothesis. According to our hypothesis, environment does not have a causal role in the development of sensitization, but it modifies the mode of expression of the sensitized behaviour. Sensitization primarily reflects a neuroadaptive change induced by repeated exposure of the neural system to psychostimulants. However, psychostimulants are known to induce different behaviours in different environments. Therefore, repeated administration of a psychostimulant in different environments would result in augmentation of different behaviours. Our hypothesis potentially accommodates various previous observations. We briefly review the literature and present our hypothesis.

Adaptation, Physiological↗
PubMed2000

[The Japanese version of the Calgary Depression Scale for Schizophrenics (JCDSS)].

Depressive features are clearly recognized within the context of schizophrenia, and clarification of the comorbidity has important clinical implications particularly when choosing the best neuroleptics for treatment. However, in some cases, it is difficult to clearly distinguish between depressive symptoms, negative symptoms and extrapyramidal side-effects. Conventionally, the Zung's Self-Rating Depression Scale or Hamilton's Depression Rating Scale has been used as an evaluation scale of depressive symptoms. However, as these scales are designed for assessment of depression in non-psychotic populations, they do not necessarily distinguish depressed from non-depressed psychotic subjects. Recently, Addington et al. developed a new depression scale, the Calgary Depression Scale for Schizophrenics(CDSS), which was designed for the assessment of depression in schizophrenia. CDSS is a nine item structured interview scale, in which each item has a four point measure, each point anchored by descriptors. It has been tested, and it has been shown that there is no overlap with negative or extrapyramidal symptoms. Therefore, for its clinical application, we prepared the Japanese-language version(JCDSS).

Depression↗
PubMed2000

[Surgery using master-slave manipulators and telementoring].

Master-slave manipulators enhance surgeons' dexterity and improve the precision of surgical techniques by filtering out surgeons' tremors and scaling the movements of surgical instruments. Among clinically available master-slave manipulators, the epoch-making system called "da Vinci" developed by Intuitive Surgical Inc. (Mountain View, CA, USA), equipped with 2 articulated joints at the tip of the surgical instruments allowing 7 degrees of freedom, mimics the movements of surgeons' wrists and fingers in the abdominal or thoracic cavity. Today advanced telecommunications technology provides us excellent motion images using only 3-ISDN telephone lines. Experienced surgeons at primary surgical sites have been able to perform complex procedures successfully by consulting specialists at remote sites. Because telecommunications costs have become lower each year, telementoring will be come a routine surgical practice in the near future. The usefulness of surgical telementoring has been greatly enhanced by the development of a technique to illustrate on video images from two directions. Moreover, remote advisory surgeons will be able to provide the optimal operative field to operating surgeons using robotic camera holders with voice-recognition systems. In the near future, when master-slave manipulators will also be coupled with telementoring systems, remote experts could actually perform complex surgical procedures.

Humans↗
PubMed2000

Scarless endoscopic thyroidectomy: breast approach for better cosmesis.

An original technique for performing endoscopic thyroidectomy using a breast approach to avoid an operative scar in the neck was developed. The subcutaneous space in the breast area and the subplatysmal space in the neck were bluntly dissected through a 15-mm incision between the nipples, and CO2 was insufflated at 6 mm Hg to create the operative space. Three trocars were inserted at the breast, and dissection of the thyroid and division of the thyroid vessels and parenchyma were performed endoscopically using an ultrasonically activated scalpel. Four hemithyroidectomies and one partial resection of the thyroid for five female patients with thyroid adenomas 5 to 7 cm in diameter were successfully performed using this procedure. There were no conversions to open surgery or complications. No scars were apparent in the neck, and all patients were fully satisfied with the cosmetic results. Endoscopic thyroidectomy using a breast approach and low-pressure subcutaneous CO2 insufflation is a feasible and safe procedure, which results in satisfactory cosmetic results.

Adenoma↗
PubMed2000

[The Japanese version of the serotonin syndrome scale (JSSS)].

The serotonin(5-HT) syndrome(SS) is a condition of both the central and peripheral 5-HTergic hyperstimulation, characterized by a constellation of 5-HT-related side effects(confusion, agitation, restlessness, myoclonus, hyperreflexia, diaphoresis, shivering or tremor in the setting of the recent addition of 5-HTergic agents. The SS is produced most often by the concurrent use of monoamine oxidase inhibitors and other 5-HTergic agents. However, more recent reports suggest that the tricyclic antidepressant or selective serotonin reuptake inhibitor(SSRI) monotherapy induces the SS. Recently, for the operationalized assessment of both the presence and the severity of the core symptoms of the SS, Hegerl et al. developed the Serotonin Syndrome Scale(SSS) as a modification of the diagnostic criteria of the SS proposed by Sternbach. Since, in Japan, some novel 5-HTergic agents have been, and will be in use, recognition of the SS is quite important. Therefore, for clinical application of SSS, we prepared the Japanese-language version (JSSS).

Diagnostic Techniques, Neurological↗
PubMed2000

[The countermeasure to pollinosis by a web site of Internet].

For the countermeasure to pollinosis, we opened "the web site of pollinosis by allergic group of otorhinolaryngology, Jikei Medical School" and provided the information of pollinosis for patients in the web site of internet from the spring of 1997. In the web site we kept to be informed of the pollen forecast, daily dispersed pollens, and medical information being renewed frequently of prevention and therapy for pollinosis. For the principle of therapy, we adopted the guideline for allergic rhinitis which was produced by Japan Allergic Societies and recommended visitors to get standard therapy for pollinosis. Consequently, the web site was accessed up to 160,000 times by the summer of 1999 and we received 204 medical questions by e-mail and answered to these all mails. We then made a questionnaire study after 3 each pollen seasons and received over 200 answers which showed that our fresh information was useful to decrease symptoms of pollinosis. These results show that information by web site seems to be useful for the countermeasure to pollinosis and will be more important to support medical treatment in hospitals in future.

Adolescent↗
PubMed1999

Mutational analysis of the anion exchanger 3 gene in familial paroxysmal dystonic choreoathetosis linked to chromosome 2q.

Familial paroxysmal dystonic choreoathetosis (PDC) is an autosomal dominant neurological disorder characterized by episodes of involuntary movement precipitated by caffeine, alcohol, or emotional stress. The locus for PDC has recently been mapped to chromosome 2q32-36, but its causative gene has not yet been identified. PDC is most likely a kind of channelopathy, as suggested by the fact that other paroxysmal neurological disorders are caused by various ion channel mutations. Although no ion channel is located in this candidate region, anion exchanger 3 (AE3) has been mapped to 2q36 and has also been reported to be the most promising candidate gene of PDC. In this study we performed sequencing of the coding region of the AE3 gene in patients with familial PDC linked to chromosome 2q and excluded the AE3 gene as the causative gene for PDC. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 88:733-737, 1999.

Amino Acid Sequence↗
PubMed1999

Effect of subchronic lithium carbonate treatment on anxiolytic-like effect of citalopram and MKC-242 in conditioned fear stress in the rat.

We investigated the effect of citalopram [selective serotonin (5-HT) reuptake inhibitor] and MKC-242 (5-[3-¿(2S)-(1, 4-Benzodioxan-2-ylmethyl) amino¿propoxy]-1, 3-benzo-dioxol hydrochloride; a selective 5-HT(1A) receptor agonist) on the expression of conditioned freezing, an index of anxiety, following treatment with subchronic lithium carbonate (LiCO(3)). Male Sprague-Dawley rats were used in these experiments. Acute administration of citalopram (subcutaneously, s.c.) reduced freezing significantly at a high dose (30 mg/kg), while showing no effect at lower doses (3 and 10 mg/kg). Acute administration of MKC-242 (s.c.; 0.1-10 mg/kg) dose dependently reduced freezing. Subchronic LiCO(3) treatment (1 week; 0.05% or 0.2% LiCO(3) in diet; p.o.) showed no effect on freezing behavior. Acute treatment with both citalopram (3 and 30 mg/kg) and MKC-242 (1 mg/kg) after subchronic treatment with the higher, but not the lower concentration of LiCO(3) (1 week), reduced freezing markedly and significantly, as compared with either drug alone. These results suggest that subchronic LiCO(3) treatment enhanced the anxiolytic-like effects of these serotonergic drugs by facilitating central 5-HT neurotransmission at clinically therapeutic plasma lithium levels.

Animals↗
PubMed1999

Suppression of protein kinase C is associated with inhibition of PYK2 tyrosine phosphorylation and enhancement of PYK2 interaction with Src in thrombin-activated platelets.

Blood platelets have recently been shown to express PYK2, a nonreceptor tyrosine kinase belonging to the FAK gene family. In this study, we examined the involvement of protein kinase C (PKC) in PYK2-related responses in human platelets. While PYK2 tyrosine phosphorylation induced by thrombin was inhibited by preincubation of platelets with PKC inhibitors, staurosporine and Ro31-8220, PYK2 association with Src was markedly enhanced under the same conditions. Platelet intracellular Ca2+ mobilization induced by thrombin was hardly inhibited by these PKC inhibitors. p130Cas is a docking protein that associates with FAK or PYK2 through the SH3 domain. Although we identified p130Cas in platelets for the first time, this docking protein failed to interact with PYK2. These results suggest that PKC activation (but not Ca2+ mobilization) is involved in PYK2 tyrosine phosphorylation and that PYK2 associates with Src without PYK2 tyrosine phosphorylation or p130Cas involvement in platelets.

Enzyme Activation↗
PubMed1999

Low susceptibility of specific inbred colonies of rats to nickel tumorigenesis in soft tissue.

Nickel sarcomatogenesis induced by a single intramuscular injection of 10 mg of nickel subsulfide (NiSS) into the soft tissue of two different colonies of Wistar rats was studied. In spontaneously hypertensive rats (SHR), a specific inbred colony of rats derived from a certain Wistar strain, the sarcoma induction rate was lower than that in common closed colony rats of the same strain (CWR). Sarcomas were induced in only 7 of the 30 rats (23.3%) in the SHR group (15 female and 15 male) but in 21 of the 31 rats (67.7%) in the CWR group (15 female and 16 male) (P < 0.005). The incidence of sarcoma induction was lower in female rats than in male rats in both the SHR (female 13.3% < male 33.3%) and CWR (female 53.3% < male 81.4%) groups. Primary tumors in the SHR group exhibited a lower grade of metastasis to lymph nodes (P < 0.001) and lungs (P < 0.05) than in the CWR group. Our study demonstrated that rats in a certain specific inbred colony are less susceptible to nickel tumorigenesis in soft tissue than rats in a common closed colony.

Animals↗
PubMed1999

Psychotic relapse and maintenance therapy in paranoid schizophrenia: a 15 year follow up.

In spite of numerous reports on a 1 to 2 year maintenance neuroleptic treatment of schizophrenia, there is little systematic information on decade-long maintenance therapy. We conducted a retrospective study in fifty outpatients with paranoid schizophrenia who have been seen at our clinic for a duration of 15 years or more since their first psychotic episodes. Relapse rate within 2, 5, 10, and 15 years from remission of the first psychotic episode were 52, 60, 86, and 90%, respectively. However, the incidence of relapse decreased with time. This decrease was accounted for by the decrease of relapse observed when off drug. Conversely, the incidence of relapse occurred on drug remained unchanged. The average maintenance dose 15 years after remission of the first psychotic episode was 5.41 +/- 7.28 mg/d (haloperidol equivalents: mean +/- SD). The maintenance dose correlated significantly with the number of relapses and total duration of psychotic episodes. These results suggest that maintenance treatment remained effective for decades, although it did not ameliorate the liability to relapse itself. Repeated relapse may be associated with requirement for a higher neuroleptic dose for relapse prevention.

Antipsychotic Agents↗
PubMed1999

Effects of the benzodiazepine antagonist flumazenil on conditioned fear stress in rats.

1. The authors investigated the effect of the benzodiazepine receptor antagonist flumazenil on freezing behavior induced by conditioned fear stress and used a time-sampling procedure. 2. Rats were individually subjected to 5 min of inescapable electric footshock in a shock chamber. Twenty-four hours after the footshock, the rats were again placed in the shock chamber and observed for 5 min without shocks: this procedure is termed conditioned fear stress. 3. Subcutaneous administration of flumazenil (10 mg/kg) 30 min before conditioned fear stress reduced conditioned freezing, while flumazenil (1-10 mg/kg) 30 min before footshock did not. This indicates that flumazenil reduced the expression of conditioned fear, suggesting an anxiolytic effect of flumazenil. 4. This effect may be attributable to antagonism by flumazenil to endogenous inverse agonist-like ligands for benzodiazepine receptors. It is suggested that endogenous inverse agonist-like ligands for benzodiazepine receptors are involved in the expression of conditioned fear stress.

Animals↗
PubMed1999

Spontaneous spiral formation in two-dimensional oscillatory media.

Computational studies of pattern formation in a modified Oregonator model of the Belousov-Zhabotinsky reaction is described. Initially inactive two-dimensional reaction media with an immobilized catalyst is connected to a reservoir of fresh reactants through a set of discrete points distributed randomly over the interphase surface. It is shown that the diffusion of reactants combined with oscillatory reaction kinetics can give rise to spontaneous spiral formation and phase waves.

Journal Article↗
PubMed1999

Bcl-2 protein expression and gut neurohormonal polypeptide/amine production in colorectal carcinomas and tumor-neighboring mucosa, which closely correlate to the occurrence of tumor.

To clarify whether advanced colorectal carcinomas and tumor-neighboring mucosa simultaneously produce both Bcl-2 protein and gut neurohormonal polypeptides and/or amines, and the interrelationship of these phenomenon, we studied retrospective analysis of Bcl-2 protein production and neuroendocrine characteristics in 52 cases of advanced colorectal carcinoma and surrounding mucosa. All of the tumor-neighboring mucosa presented hyperplasia. The rates of enhanced immunoreactivity of the tumor-neighboring mucosa and of positive immunoreactivity of the carcinomas against human Bcl-2 protein and against human vasoactive intestinal polypeptide, pancreatic polypeptide and somatostatin were 78.8% and 94.2%, 82.7% and 59.6%, 78.8% and 67.3%, and 88.5% and 84.6% respectively. Double immunostaining for Bcl-2 protein and each peptide hormone revealed simultaneous expression. In contrast, that of tumor-neighboring mucosa and carcinomas to serotonin and chromogranin-A and to argyrophilia were 11.5% and 1.9%, 32.7% and 17.3%, and 26.9% and 21.2%, respectively. We concluded that tumor-neighboring crypt cells displayed not only hyperplasia but also neuroendocrine characteristics and that enhanced Bcl-2 protein immunoreactivity correlated with tumor occurrence in the wall of the colorectum. The production of Bcl-2 protein by tumor cells and tumor-neighboring crypt cells indicates that the bcl-2 protooncogene may act not only as an inhibitor of apoptosis but also as an inducer of neuroendocrine differentiation from the latent characteristics of the endodermal stem cell.

Adult↗