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Biomedical subjects

K Kurita

Publications and source records attributed to K Kurita.

At least 19 recordsLinked to original sources
PubMed2006

The role of muscle grafts in temporomandibular joint ankylosis: short-term experimental study in sheep.

The temporalis muscle flap can be used as an inter-positional graft placed into a gap arthroplasty site in temporomandibular joint (TMJ) ankylosis. The purpose of this study was to investigate the role of the muscle graft in sheep. Five pure-bred adult Merino sheep were used and ankylosis was induced in all right TMJs. At 3 months, the ankylosis was released by gap arthroplasty and reconstructed with a masseter muscle graft, because the temporalis muscle is short and poorly vasculized in sheep. The sheep were killed at 3 months after muscle grafting. The maximal mouth opening was recorded before and after operation and at death. The joints were examined radiologically and histologically. In 4 sheep mouth opening remained at the pre-operative level. A clear radiolucent space remained between the smooth temporal and ramus stumps. Histologically, the muscle graft remained vital but with some fibrous tissue formation between the bone ends. One sheep developed an infection at the operative site following the muscle graft; this partly resolved with antibiotics, but the TMJ developed a fibrous reankylosis that was demonstrated clinically, radiologically and histologically. These results indicate that an uncomplicated temporalis muscle graft reconstruction with gap arthroplasty is a successful and stable procedure in human TMJ ankylosis.

Animals↗
PubMed2006

Vanishing N = 20 shell gap: study of excited states in (27,28)Ne.

This Letter reports on the (1)H((28)Ne, (28)Ne) and (1)H((28)Ne, (27)Ne) reactions studied at intermediate energy using a liquid hydrogen target. From the cross section populating the first 2(+) excited state of (28)Ne, and using the previously determined BE(2) value, the neutron quadrupole transition matrix element has been calculated to be M(n)=13.8 +/- 3.7 fm(2). In the neutron knockout reaction, two low-lying excited states were populated in (27)Ne. Only one of them can be interpreted by the sd shell model while the additional state may intrude from the fp shell. These experimental observations are consistent with the presence of fp shell configurations at low excitation energy in (27,28)Ne nuclei caused by a vanishing N=20 shell gap at Z=10.

Journal Article↗
PubMed2006

Increase in RANKL: OPG ratio in synovia of patients with temporomandibular joint disorder.

Although a recent study suggested the involvement of RANKL and osteoprotegerin (OPG) in the pathogenesis of bone-destructive disease, no study has focused on the RANKL:OPG ratio in the synovial fluid of patients with temporomandibular joint (TMJ) disorder. This communication reports on the concentrations of RANKL and OPG in synovial fluid from TMJ patients and healthy control individuals. In contrast to an unchanged concentration of RANKL, a strong decrease in the concentration of OPG was detected in the synovial fluid from patients with TMJ internal derangement. Treatment with the synovial fluid of osteoarthritis (OA) patients resulted in the high production of osteoclast-like cells from blood mononuclear cells in vitro, as well as in pit formation in dentin slices. The addition of anti-RANKL IgG or OPG attenuated OA-synovial fluid-induced osteoclast formation, suggesting that the increase in the RANKL:OPG ratio in the microenvironment of the joint has the potential to induce osteoclastogenesis in TMJ osteoarthritis.

Adult↗
PubMed2005

A downward spread in acute parotitis.

Acute parotitis occasionally spreads rapidly down the neck with severe symptoms of swelling and pain. However, the inflammatory course of parotitis with extraglandular spread has seldom been described. On CT images, we have noticed a unique area just below the parotid gland that is surrounded by the platysma muscle and the superficial layer of the deep cervical fascia (DCF). In this case report, we describe the CT imaging features of acute parotitis, focusing on this area.

Adult↗
PubMed2004

Anomalously hindered E2 strength B(E2;2+(1)-->0+) in 16C.

The electric quadrupole transition from the first 2(+) state to the ground 0(+) state in 16C is studied through measurement of the lifetime by a recoil shadow method applied to inelastically scattered radioactive 16C nuclei. The measured mean lifetime is 77+/-14(stat)+/-19(syst) ps. The central value of mean lifetime corresponds to a B(E2;2+(1)-->0(+)) value of 0.63e(2) fm(4), or 0.26 Weisskopf units. The transition strength is found to be anomalously small compared to the empirically predicted value.

Journal Article↗
PubMed2004

Lateral and medial medullary infarction: a comparative analysis of 214 patients.

BACKGROUND AND PURPOSE: No large-scale study has ever compared the clinical and radiological features of lateral medullary infarction (LMI) and medial medullary infarction (MMI). The aim of this study was to investigate them through the use of cooperatively collected cases. METHODS: Medical information on all patients from 1996 to 2000 with medullary infarction (MI) proven by brain MR images at 35 stroke centers in the Tohoku district, Japan, was collected, and their clinical and radiological features were analyzed. RESULTS: A total of 214 cases of MI were registered. They included 167 cases (78%) of LMI, 41 (19%) of MMI, and 6 (3%) of LMI plus MMI. The mean age of onset and the male-to-female ratio were 60.7 years and 2.7:1 in LMI and 65.0 years and 3.6:1 in MMI, respectively. The middle medulla was most frequently affected in LMI, and the upper medulla was most frequently affected in MMI. Dissection of the vertebral artery was observed in 29% of LMI and 21% of MMI. Prognosis, assessed by the Barthel Index, was favorable in both LMI and MMI. Diabetes mellitus was more frequently associated with MMI than with LMI. CONCLUSIONS: The present study surveyed a large number of MI cases and revealed that (1) the mean age of onset of MMI is higher than that of LMI, (2) the dissection of the vertebral artery is an important cause not only of LMI but also of MMI, and (3) diabetes mellitus is frequently associated with MMI.

Age Factors↗
PubMed2003

External validity of a randomised clinical trial of temporomandibular disorders: analysis of the patients who refused to participate in research.

PURPOSE: To assess the external validity of a randomised clinical trial (RCT) of a painful condition. METHOD: Consecutive patients with painful temporomandibular disorders (TMDs) were invited to participate in a clinical trial. Patients who refused to participate were compared to those who agreed to participate in this study with respect to degree of symptoms at time of presentation. RESULTS: The patients who refused to participate had more pain, and their condition interfered more with their daily life than those who accepted the invitation to participate. CONCLUSION: Selection bias in RCTs of painful conditions can skew the results, and external validity should be analysed before the results are generalised.

Activities of Daily Living↗
PubMed2003

Effects of a single arthrocentesis and a COX-2 inhibitor on disorders of temporomandibular joints. A preliminary clinical study.

Our aim was to examine the short-term effect of combined treatment with single arthrocentesis and a COX-2 inhibitor on 26 patients with severe symptoms of temporomandibular joint (TMJ) disorders. The severity of the disorders was graded according to the degree of restriction of mouth opening and pain score on a visual analogue scale. Synovial fluid was collected from the superior joint space of the affected TMJ, and arthrocentesis was done with isotonic saline, 200ml. Subsequently, etodolac, 400mg/day, was given for 2 weeks. At 14 days, patients were re-examined and further specimens of synovial fluid were collected. Patients generally lost their symptoms and the severity of the disorders improved significantly (P<0.01). The concentrations of total protein and albumin in synovial fluid decreased with no statistical significance. However, the concentration of matrix metalloproteinase-3 and its ratios to total protein and albumin did decrease significantly (P<0.05). Our results suggest that a larger controlled study is necessary to clarify the contributory effect of arthrocentesis and etodolac for patients with severe symptoms of TMJ disorders.

Adolescent↗
PubMed2003

A case of inflammatory demyelinating polyradiculoneuropathy associated with T-cell lymphoma.

Malignant lymphoma may present prominent peripheral nervous system disorders with variable etiologies. We describe a patient who presented with chronic relapsing polyradiculoneuropathy accompanied by right facial nerve palsy. Gadolinium enhancement of the right facial nerve and cervical spinal roots was noted on magnetic resonance imaging (MRI). Sural nerve biopsy specimens showed mononuclear cell infiltration around the vessels in the epineurium. Histopathological and immunohistochemical investigations of sural nerve specimens revealed perivascular infiltration of lymphocytes with T-cell dominancy. No apparent direct invasion of lymphoma cells was seen. The results of nerve conduction studies, sural nerve biopsy and cerebrospinal fluid examination were suggestive of immune-mediated inflammatory demyelinating neuropathy. The chronic and relapsing fashion and unique radiological findings in our patient expand on the previously reported features of peripheral neuropathy associated with peripheral T-cell lymphoma.

Biopsy↗
PubMed2003

Inhibitory effect of titanium particles on osteoclast formation generated by treatment of mouse bone marrow cells with PGE2.

OBJECTIVE: The present study was designed to evaluate the effect of titanium (Ti) particles with no endotoxin on osteoclast differentiation and osteoclast activity in in vitro experiments. METHODS: Osteoclast formation as well as osteoclastic bone resorbing activity were examined using the mouse bone marrow culture system and purified rabbit osteoclasts treated with Ti particles (2.5-20 microgram cm-2). RESULTS: Ti particles, with no adherent endotoxin, inhibited osteoclastogenesis and receptor activator of NF-kappaB ligand (RANKL) expression in bone marrow cells treated with prostaglandin E2 (PGE2) (100 nM). The inhibitory effect of Ti particles was concentration-dependent (5-20 microgram cm-2), and was observed only on the generation of osteoclasts by PGE2, but not by 1,25-dihydroxyvitamin D3 or soluble RANKL. This suggests that Ti particles did not act uniformly on a common process in the generation of osteoclasts, but specifically on signal transduction for PGE2 in generating osteoclasts. In highly purified osteoclasts, Ti particles showed no effect on survival and bone resorbing activity. CONCLUSION: Ti particles inhibited osteoclast differentiation and RANKL expression in mouse bone marrow cells treated with PGE2, without affecting mature osteoclast survival or activity. Thus, Ti particles may alter the osteoclastogenetic action of PGE2, which is one of the regulatory factors of bone remodeling.

Animals↗
PubMed2003

Ankylosis of the temporomandibular joint developing shortly after multiple facial fractures.

A 41-year-old male patient was referred for treatment of extensive facial fractures and lateral condylar dislocations. The patient underwent open reduction and fixation under general anaesthesia. Intermaxillary fixation was released in 2 weeks and mouth opening was 21 mm. Despite postoperative physical exercises, the range of motion decreased to 10 mm at 5 weeks after the surgery. MR arthrography revealed a fibrous ankylosis in the bilateral TMJs. Coronal CT scans depicted a bony outgrowth of the left TMJ tuber. The patient underwent surgery for the ankylosis including discectomy and coronoidectomy, and removal of the bony outgrowth. An interincisal distance of 30 mm on maximal mouth opening has been maintained for 14 postoperative months. The importance of imaging assessment was emphasized for diagnosing the precise pathologic state of the ankylosis and selecting an appropriate surgical treatment of choice.

Adult↗
PubMed2002

Measurement of analyzing power for proton-carbon elastic scattering in the coulomb-nuclear interference region with a 22-GeV/c polarized proton beam.

The analyzing power for proton-carbon elastic scattering in the Coulomb-nuclear interference region of momentum transfer, 9.0x10(-3)<-t<4.1x10(-2) (GeV/c)(2), was measured with a 21.7 GeV/c polarized proton beam at the Alternating Gradient Synchrotron of Brookhaven National Laboratory. The ratio of hadronic spin-flip to nonflip amplitude, r(5), was obtained from the analyzing power to be Rer(5)=0.088+/-0.058 and Imr(5)=-0.161+/-0.226.

Journal Article↗
PubMed2002

Rayleigh-Bénard convection with an inclined upper boundary.

We report experiments on thermally driven convection of a high-Prandtl-number fluid with an inclined upper boundary. For an inclined angle greater than the critical value, we observed a few new convection patterns, in which laterally migrating convection cells and plumes appear simultaneously and a large-scale flow is induced from the inclined upper boundary. The plumes induced from the inclined upper boundary activate the temperature fluctuations, resulting in the formation of a large-scale horizontal heat transfer with a lateral scale larger than that of each convection cell. The critical angle for the onset of the lateral migration of the cells is determined by comparing the two length scales: the height difference in one convection cell imposed by the inclined upper boundary and the thickness of the viscous boundary layer.

Journal Article↗
PubMed2002

Odontogenic infection pathway to the submandibular space: imaging assessment.

The aims of this study were to determine the pathways of odontogenic infection spread into the submandibular space and their relationship to the clinical symptoms. Computerized tomography (CT) and magnetic resonance (MR) images of 33 patients with submandibular involvement were analyzed. The spread of infection was evaluated by lateral asymmetry of the shape and density of the fascial spaces and tissues, and by obliteration of the interfascial fat spaces. Imaging findings were classified into three types: in 19 patients (57.6%), infection spread through the mylohyoid muscle or sublingual space (type I). In five patients (15.2%), infection spread through the bony structures of the mandible with periosteal reaction or perforation of the cortical plate (type II) and was associated with relatively mild symptoms. In four patients (12.1%), infection spread from the masticatory space (type III). Seven of 11 patients with dysphagia or fever showed submandibular involvement spreading into the parapharyngeal space. CT and MR imaging clearly demonstrated different pathways of the spread of odontogenic infection into the submandibular space, which influenced the manifestation of clinical symptoms.

Adipose Tissue↗
PubMed2001

Galectin-1 is a component of neurofilamentous lesions in sporadic and familial amyotrophic lateral sclerosis.

In amyotrophic lateral sclerosis (ALS), abnormal accumulation of neurofilaments induces pathological changes such as axonal spheroids, cord-like neurite swellings, and perikaryal conglomerate inclusions in degenerating motor neurons of the spinal cord, and the accumulation seems to cause motor neuron degeneration in this disease. Such ALS lesions were intensely labeled with HepSS-1, a monoclonal antibody to heparan sulfate. Since the identification of HepSS-1-immunoreactive substance seems to be an important step for understanding the molecular pathology of ALS, we purified the substance from human spinal cord tissue to homogeneity. Amino acid sequence of the protein was consistent with that of galectin-1. Immunohistochemistry using antibodies against recombinant human galectin-1 showed that galectin-1 was accumulated in these lesions in ALS. Although HepSS-1 was believed to be specific for heparan sulfate, it reacted with recombinant human galectin-1 which has no heparan sulfate moiety. The results show that galectin-1 is a component of the neurofilamentous lesions in ALS. Since galectin-1 has axonal regeneration-enhancing activity, the abnormal accumulation of galectin-1 to the lesions seems to be related to the pathological process of ALS.

Aged↗
PubMed2001

Colour Doppler sonographic analysis of blood-flow velocity in the human facial artery and changes in masseter muscle thickness during low-level static contraction.

Muscle oedema, which can be seen as a thickness increment by ultrasonography, is important in provoking pain and fatigue during low-level contraction. Although oedema is related to the balance of inflow and outflow of blood, there are no data on the correlation between muscle thickness change and blood-flow. Blood-flow velocities in the facial artery and the muscle thickness changes were measured by colour Doppler ultrasonography in 30 healthy volunteers during 20 min contraction with 10% of maximum force. Thickness and velocity changes both reached a peak in the initial phase of contraction. The initial change of thickness did not correlate with the velocity in the facial artery, while those immediately after exercise showed a high correlation. The velocity changes in the facial artery might depend on both the general response to contraction and local metabolic or mechanical factors in the contracted masseters.

Adolescent↗
PubMed2001

Preparation of nanoparticles composed with bioinspired 2-methacryloyloxyethyl phosphorylcholine polymer.

The poly(L-lactic acid) nanoparticles immobilized with 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer, which has excellent blood compatibility, were prepared by a solvent evaporation technique using the water-soluble amphiphilic MPC polymer as an emulsifier and a surface modifier. The diameter and zeta-potential of the obtained nanoparticles strongly depended on the concentration of the MPC polymer. When the nanoparticles were prepared in 1.0 mg/ml of an MPC polymer aqueous solution, the diameter was 221 nm which was determined by atomic force microscopy and dynamic light scattering measurements. The X-ray photoelectron spectroscopic analysis indicated that the phosphorylcholine groups of the MPC unit were located at the surface of the nanoparticles, that is, the MPC polymer was immobilized on the PLA particles and the surface zeta-potential was -2.5 mV. Various hydrophobic fluorescence probes could permeate through the MPC polymer layer and adsorb on the PLA surface. The amount of bovine serum albumin adsorbed on the nanoparticles was significantly smaller compared with that on the conventional polystyrene nanoparticles. It is suggested that the nanoparticles immobilized with the MPC polymer have the potential for use as both a novel drug carrier and diagnostic reagent which can come in contact with blood components.

Adsorption↗