Biomedical subjects

H Murata

Publications and source records attributed to H Murata.

At least 37 records · Page 2Linked to original sources

PubMed2002

Dynamic properties of bovine temporomandibular joint disks change with age.

The temporomandibular joint disk exhibits morphological and biochemical age-related changes. However, the possible age-related changes of the dynamic viscoelasticity in the disk are unclear. We tested the hypothesis that the dynamic viscoelastic properties of the disk change with age. Thirty-six disks from young-adult, adult, and mature-adult cattle were used for dynamic tensile tests. In all disks, the magnitudes of the complex modulus, the storage modulus, and the loss modulus increased as the frequency increased. The mature-adult disks had higher values of these moduli than did the younger disks. The loss tangent ranged from 0.1 to 0.3, which means that the disk has relatively large elasticity and relatively small viscosity. It was concluded that both the elasticity and viscosity of the disk increase with age. This may reflect age-related changes in biochemical composition.

Aging↗

PubMed2002

Investigating the cellular targets of HIV protease inhibitors: implications for metabolic disorders and improvements in drug therapy.

The use of HIV protease inhibitors (PIs) may be associated with serious adverse side effects that include fat tissue redistribution, hyperlipidemia, and insulin resistance. The etiology of this toxic metabolic syndrome (commonly referred to as 'HIV lipodystrophy syndrome') remains to be elucidated. The interpretation of available clinical data on this subject is complicated in part by the pervasiveness of potential confounding factors that cannot be easily eliminated or adequately controlled. Numerous investigators have examined the effects of PIs on cellular processes in model systems amenable to extensive experimental manipulations; the present review primarily focuses on these efforts. The ultimate goal is the unambiguous identification of discrete cellular targets being surreptitiously impacted by PIs. SREBP and Glut4 are discussed as candidate target molecules in this context. The identification of cellular factors interacting with PIs represents a necessary first step in devising rational strategies for improvement in drug therapy.

Adipocytes↗

PubMed2002

Dynamic viscoelasticity of soft liners and masticatory function.

Soft denture liners are used for edentulous patients to cushion functional forces. We hypothesized that the application of soft liners having viscoelastic properties would lead to the most marked improvement in masticatory function. The shear storage modulus (G'), shear loss modulus (G''), and loss tangent (tan delta) were determined for 6 materials by means of a dynamic viscoelastometer. Masticatory function of ten subjects was evaluated by measurements of maximum bite forces and chewing times and frequencies for 2 food samples, and by the use of visual analogue scales. The acrylic materials exhibited viscoelastic behavior, while the silicones exhibited elastic behavior. The improvement in masticatory function compared with hard resin was found to be in the order: acrylic permanent materials > silicone > acrylic temporary materials. The results suggest that the use of materials with higher tan delta and G' provides the most optimum masticatory function for patients requiring the provision of soft liners on their dentures.

Acrylic Resins↗

PubMed2002

Suppressive effect of zearalenone, an estrogenic mycotoxin, on bovine neutrophil chemiluminescence.

The effects of zearalenone (ZEA), an estrogenic mycotoxin produced by Fusarium fungi, on bovine neutrophils were investigated in vitro using chemiluninescence, a bactericidal parameter. ZEA suppressed luminol-dependent, phorbol 12-myristate 13-acetate (PMA)-elicited chemiluminescence in a dose-dependent manner at concentrations of 10(-4) M and 10(-5) M. No significant suppression was observed at concentrations lower than 10(-6) M. The possible mode ofaction of 10(-4) M ZEA on the cell activity was investigated with special reference to intracellular Ca2+ ([Ca2+]i) release and estrogen receptors. The 10(-4) M ZEA treatment significantly impaired [Ca2+]i release. When pretreated with a low dose (10(-6) M) of PMA, the cells resisted the ZEA-induced chemiluminescence suppression. However, pretreatment of the cells with the estrogen receptor blockers Tamoxifen and ICl 182,780 (both at 10(-6) M) did not annul the suppressive ZEA action. Considering that PMA is an activator of protein kinase C (PKC), a signal transducing enzyme, and in association with a rise in [Ca2+]i causes cytosolic PKC to shift to the plasma membrane where the activated PKC triggers a varied array of cellular responses, the pharmacological dose of ZEA might have suppressed chemiluminescence by hindering the release of [Ca2+]i and the PKC shift. The results of pretreatment with estrogen receptor blockers, however, did not support the suggestion that the ZEA treatment affected the cells via estrogen receptor pathways.

Animals↗

PubMed2001

Validation of an analytical method for a potent antitumor agent, TZT-1027, in plasma using liquid chromatography-mass spectrometry.

A sensitive and specific analytical method for a potent antitumor agent, TZT-1027, in plasma has been developed using liquid chromatography-mass spectrometry (LC-MS) with [2H4]TZT-1027 as an internal standard (I.S.). A plasma sample was purified by solid-phase extraction on a C18 cartridge, followed by solvent extraction with diethyl ether. The extract was then injected into the LC-MS system. Chromatography was carried out on a C18 reversed-phase column using acetonitrile-0.05% trifluoroacetic acid (TFA) (55:45) as a mobile phase. Mass spectrometric analysis was performed in atmospheric pressure chemical ionization (APCI) mode with positive ion detection, and the protonated molecular ions ([M+H]+) of TZT-1027 and I.S. were monitored to allow quantitation. The method was applied to the determination of TZT-1027 in human, monkey, dog, rat and mouse plasma. As far as the sample preparation was concerned, good recoveries (73.5-99.1%) were obtained. The calibration curves were linear over the range of 0.25-100 ng per 1 ml of human, dog and rat plasma, per 0.5 ml of monkey plasma, and per 0.1 ml of mouse plasma. From the intra- and inter-day accuracy and precision, the present method satisfies the accepted criteria for bioanalytical method validation. TZT-1027 was stable when stored below -15 degrees C for 6 months in human plasma and for 3 weeks in plasma from other species. TZT-1027 was also stable in plasma through at least three freeze-thaw cycles.

Animals↗

PubMed2001

IL-6 up-regulates CNTF mRNA expression and enhances neurite regeneration.

Interleukin-6 (IL-6) is a neurotrophic cytokine, however, its direct effect on nerve regeneration has not been well characterized. We therefore examined the effect of IL-6 on neurite regeneration using the rat dorsal root ganglion. IL-6 significantly enhanced neurite regeneration from transected nerve terminals. We also examined the mRNA expression of IL-6 family cytokines and their receptors during the regeneration. The mRNA expressions of IL-6, IL-6 receptor, leukemia inhibitory factor (LIF), ciliary neurotrophic factor (CNTF) receptor alpha, and LIF receptor beta showed no significant differences by the addition of IL-6. In contrast, IL-6 enhanced the mRNA expression of gp130 and CNTF. In addition, CNTF significantly increased neurite regeneration when added exogenously. Our data suggest that IL-6 enhanced regeneration via up-regulating CNTF expression.

Animals↗

PubMed2001

Experimental transmission of sheep-associated malignant catarrhal fever from sheep to Japanese deer (Cervus nippon) and cattle.

The assumption that sheep carry ovine herpesvirus-2 (OvHV-2), the causative agent of sheep-associated malignant catarrhal fever (SA-MCF), is widely accepted, albeit OvHV-2 has not been isolated. We attempted experimental contact transmission of MCF from Japanese sheep persistently infected with OvHV-2 to Japanese deer (Cervus nippon) and cattle. In Experiment 1, a deer was kept in close quarters with an infected ewe. In Experiment 2, a second deer was kept with the same ewe. In Experiment 3, two cows were each kept with two infected wethers. In Experiment 1, the deer developed clinical signs at 138 days after first contact and then died. OvHV-2 genes by polymerase chain reaction (PCR) and fluorescent antibodies to Alcelaphine herpesvirus-1 were detected in the affected deer. Moreover, sequences of PCR products (423bp), obtained by amplification of materials from the sheep and from the affected deer, coincided. These results clearly confirmed that the sheep was a carrier of OvHV-2, and that this virus had induced SA-MCF in a deer. In other experiments, no OvHV-2 infection occurred in deer and cattle during the 6-18 months periods of contact, though viral genes were detected in the nasal swabs and white blood cells of the sheep. To our knowledge, this is the first report on successful experimental transmission of MCF from OvHV-2-infected sheep to deer.

Animals↗

PubMed2001

Extraskeletal osteosarcoma arising in myositis ossificans.

A 53-year-old woman had extraskeletal osteosarcoma that developed from a soft tissue bony mass present on the volar aspect of the left wrist for 4 years. Initially, the bony mass was soft and movable, but during the first year it became hard and fixed. The patient had no history of trauma. Because the lesion did not grow or cause any symptoms, the patient did not come to the hospital until 4 years after she first noticed the lesion. Radiologically, the bony mass had features characteristic of mature myositis ossificans, showing "eggshell" ossification. A nonmineralized soft tissue mass occurred between the surface of the radius and the bony shell. Histologically, a high-grade osteosarcoma was present between the surface of the radius and the well-differentiated bone tissue, which included fatty and hematopoietic marrow. All the findings indicated that our patient had an extremely rare case of malignant transformation of myositis ossificans.

Female↗

PubMed2001

Ceramic endoprosthesis for aggressive giant cell tumors near the knee: eight cases followed for more than 10 years.

Eight patients with locally aggressive giant cell tumor were treated with marginal resection and implantation of a ceramic endoprosthesis with a non-hinged knee joint. The patients have been followed-up for between 10 to 16 years. Newly formed bone appeared at the junction between implant and cortex and in 2 cases subsidence of the implant was seen. All the patients had good function of the knee and no revision was needed.

Adult↗

PubMed2001

Analysis of T cell receptor V(beta) gene expression and clonality in bronchoalveolar fluid lymphocytes from a patient with chronic eosinophilic pneumonitis.

Chronic eosinophilic pneumonitis (CEP) is characterized by longstanding respiratory symptoms accompanied by a massive pulmonary eosinophil infiltration. T lymphocytes in bronchoalveolar lavage (BAL) from patients with chronic eosinophilic pneumonitis are considered to recognize unknown antigens. To analyze the pathogenesis of CEP, we examined the T cell receptor (TCR) repertoire and T cell clonotype of BAL lymphocytes and peripheral blood lymphocytes (PBLs) in a 66-year-old woman patient with CEP. The expression of TCR BV gene was analyzed by the family PCR method using specific primers for 20 TCR BV genes and BC gene. The clonotype of BAL and peripheral T cells was examined by the PCR-single-strand conformation polymorphism (SSCP) method. Functional sequences of some T cell clones were also carried out. A TCR repertoire of BAL T cells was heterogeneous as well as PBLs. However, SSCP analysis showed that distinct T cell clonotypes were detected in BAL T cells, TCR BV3, BV4, BV6, BV8, BV9, BV14, and BV18-positive T cell clones especially, expanded clonally in BAL from the patient. Sequencing analysis showed that GVD, LGG, RDXS, and SSG amino acid sequence motif were found in the CDR3 in lung-specific T cells. BAL-specific T cell clones accumulated in the patient with CEP. Thus, we can conclude that BAL T cells are induced by the antigen-driven stimulation and these cells might play a crucial role in the generation of CEP.

Aged↗

PubMed2001

Possible involvement of vitamin D receptor gene polymorphism in male patients with ossification of spinal ligaments.

Ossification of spinal ligaments (OSL) is a common form of myelopathy characterized by heterotopic bone formation in the spinal ligaments, predominantly in men. Although the etiology of OSL is not fully understood, previous studies have strongly suggested the involvement of genetic factors in this disease. To investigate the possible involvement of vitamin D receptor (VDR) gene polymorphism in Japanese male patients with OSL, we analyzed: (a) the VDR genotype defined by BsmI polymorphism in patients with obvious OSL and controls; and (b) the effect of 1,25-dihydroxyvitamin D3 on alkaline phosphatase (ALP) activity of spinal ligament cells derived from patients without OSL. With regard to the VDR genotype, of the patients with OSL (n = 27), none had the BB genotype (0%), one had the Bb genotype (4%), and 26 had the bb genotype (96%). In the control group (n = 97) three had the BB genotype (3%), 18 had the Bb genotype (19%), and 76 had the bb genotype (78%). As a result, the B allele frequency in patients with OSL (2%) was significantly lower than in controls (12%). 1,25-Dihydroxyvitamin D3, at concentrations of 10-9 and 10-8 M, significantly increased ALP activity of the ligament cells (n = 8), suggesting that 1,25-dihydroxyvitamin D3 is able to promote osteogenic differentiation of normal ligament cells. Among the Japanese, sensitivity to vitamin D has been reported to vary between the alleles of the VDR; i.e., bone mineral density (BMD) in patients without the B allele is increased by vitamin D treatment, whereas patients with the B allele do not show such an increase in BMD. The present investigation is a small preliminary study, but the findings suggest, for the first time, that the B allele of the VDR acts as an inhibitor in the pathogenesis of human male OSL.

24,25-Dihydroxyvitamin D 3↗

PubMed2001

Gastric signet ring cell adenocarcinoma metastatic to the iris.

PURPOSE: To report a case of gastric signet ring cell adenocarcinoma metastatic to the iris. METHODS: Case report. A 38-year-old man with a history of gastric signet ring cell adenocarcinoma presented with a white lacework-like mass on the iris of the left eye. RESULTS: Systemic medical evaluation demonstrated no other metastasis. Because of increased intraocular pressure, trabeculectomy and peripheral iridectomy were performed. Histology of the iris specimen demonstrated metastasis of gastric signet ring cell adenocarcinoma to the iris. CONCLUSION: Gastric signet ring cell carcinoma can metastasize to the iris. Ophthalmologists should include this possibility in the differential diagnosis when encountering a patient with a history of gastric adenocarcinoma and an iris mass.

Adult↗

PubMed2001

A congenital dermal sinus presenting the muscle fasciculation and hypertrophy.

OBJECTIVE: To report unique and unknown clinical features of muscle fasciculation and muscle hypertrophy in a case of congenital dermal sinus. PATIENTS: A 16-year-old girl presented with continuous fasciculation, often cramp, and hypertrophy of the left calf muscle. The radiography showed spina bifida of L4, L5 and S1. MRI revealed dermal sinus tract from the skin dimple of the back to the dura mater, and connected to the intradural inclusion tumor. At surgery the inclusion tumor contained many short hairs, and the cauda equina were severely adherent. Microdissection of the tumor and the adhesion was performed. At 2 years after surgery fasciculation decreased but continued; however, painful cramps of the calf muscle do not occur. CONCLUSIONS: Short hairs of dermoid and the adherence might be irritative to the cauda equina. The hyperactivity of the stimulated motor neuron may cause the muscle fasciculation leading to hypertrophy of the calf muscle.

Adolescent↗

PubMed2001

Effect of addition of ethyl alcohol on gelation and viscoelasticity of tissue conditioners.

The clinical effectiveness of tissue conditioners is influenced by their gelation characteristics and viscoelastic properties after gelation. The purpose of this study was to evaluate the effect of addition of ethyl alcohol (EtOH) on these properties, and to compare the effect of EtOH with that of the powder/liquid (P/L) ratio. Three tissue conditioners were used in this study. The gelation times were obtained with an oscillating rheometer. The viscoelastic properties after gelation were also evaluated by stress relaxation tests. Addition of greater amounts of EtOH produced the shorter gelation time and the larger flow after gelation. Conversely, although the use of a higher P/L ratio produced a shorter gelation time, this procedure leads to a smaller flow after gelation. The results suggested that the addition of EtOH to the liquids of tissue conditioners is an effective method for controlling gelation times and viscoelastic properties after gelation.

Algorithms↗

PubMed2001

Dimensional stability and weight changes of tissue conditioners.

The dimensional stability of tissue conditioners characterizes the ability of the materials to yield accurate functional impressions of oral mucosa. This study evaluated the linear dimensional changes with time of six tissue conditioners (COE Comfort, FITT, GC Soft-Liner, Hydro-Cast, SR-Ivoseal and Visco-Gel) using a travelling microscope, and relationship between these changes and weight changes. The absorption and solubility of these materials were also determined. The percentage changes in dimension and weight in water storage were measured at 2 (baseline), 8 and 24 h, and 2, 4, 7, 14 and 21 days after specimen preparation. All materials except SR-Ivoseal exhibited shrinkage and weight loss during water storage, whilst SR-Ivoseal exhibited expansion and an increase in weight. The percentage solubility for all materials except SR-Ivoseal was higher than the percentage absorption. A positive linear relationship was found between the percentage changes in linear dimension and those in weight (r=0.797 - 0.986, P < 0.05). Water absorption and solubility of the materials were found to be associated with dimensional changes. The results suggest that the period recommended for forming functional impressions would be 24 h after insertion in the mouth. In addition, it is important to select tissue conditioners suitable for functional impressions because of the wide ranges of dimensional stability among the materials.

Absorption↗

PubMed2001

Effect of viscoelastic properties of resilient denture liners on pressures under dentures.

In order to evaluate the influence of viscoelastic properties of resilient denture liners on the pressures under dentures, a series of creep and stress relaxation tests were carried out using a simplified mandibular edentulous model and denture model. Two diaphragm pressure sensors were attached to the edentulous model so that they contacted the residual ridge and the buccal slope. The results may be summarized as follows: (i) The use of resilient denture liners is effective for stress relief under dentures. (ii) The thickness increase of each denture liners causes the effect of stress relaxation. (iii) The material exhibited viscoelastic behaviour after applying the stress and has the ability to distribute stress or stress relaxation. It is important to understand the viscoelastic behaviours of each resilient denture liner and choose the material according to the clinical situation. The information obtained should be useful to clinicians when they select materials for their patients.

Acrylic Resins↗

PubMed2001

CC-chemokine receptor 6 and its ligand macrophage inflammatory protein 3alpha might be involved in the amplification of local necroinflammatory response in the liver.

It is not fully understood how antigen-specific or-nonspecific T cells migrate into the liver in various liver diseases. Macrophage inflammatory protein (MIP)-3alpha is a chemokine that is expressed mostly in the liver, and the receptor CCR6 is reported to be expressed on memory T cells. In the present study, we focused on the expression of CCR6 on T cells from peripheral blood (PB) and inflamed liver, and analyzed the involvement of MIP-3alpha and CCR6 in the immunopathogenesis of liver diseases. Intrahepatic T cells showed significantly (P <.0001) higher percentages of CCR6(+)CD4(+) T cells compared with PB, which is significantly (P =.037) correlated with the necroinflammatory response in the liver. Most of intrahepatic CCR6(+)CD4(+) cells were also positive for CCR5, which is known to express on T-helper 1 cells. MIP-3alpha was stained in the cells located near piecemeal necrosis, where dendritic cells (DCs) are often observed, and coculture of activated DCs with apoptotic cells induced MIP-3alpha production from the DCs. These data suggest that MIP-3alpha is produced by periportal DCs and/or macrophages after necroinflammatory response, leading to the recruitment of activated T cells into the liver. This process could be important to augment the local immune response in the livers of various liver diseases. The finding might be important not only for the understanding of immunopathogenesis of liver diseases but also for the therapeutic strategy to control the local immune response in the liver.

Antigens, CD↗

PubMed2001

Simultaneous anterior and posterior interosseous nerve paralysis with several hourglass-like fascicular constrictions in both nerves.

A patient with simultaneous anterior and posterior interosseous nerve paralysis was treated surgically with interfascicular neurolysis and found to have several hourglass-like fascicular constrictions in both nerves. Anterior and posterior interosseous nerve paralyses with hourglass-like fascicular constrictions have been described previously, but not the combination of the two.

Adult↗