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Biomedical subjects

K Honda

Publications and source records attributed to K Honda.

At least 19 recordsLinked to original sources
PubMed2006

Expression of superficial zone protein in mandibular condyle cartilage.

OBJECTIVE: Superficial zone protein (SZP) has been shown to function in the boundary lubrication of articular cartilages of the extremities. However, the expression of SZP has not been clarified in mandibular cartilage which is a tissue that includes a thick fibrous layer on the surface. This study was conducted to clarify the distribution of SZP on the mandibular condyle and the regulatory effects of humoral factors on the expression in both explants and fibroblasts derived from mandibular condyle. METHODS: The distribution of SZP was determined in bovine mandibular condyle cartilage, and the effects of interleukin-1beta (IL-1beta) and transforming growth factor-beta (TGF-beta) on SZP expression were examined in condyle explants and fibroblasts derived from the fibrous zone of condyle cartilage. RESULTS: SZP was highly distributed in the superficial zone of intact condyle cartilage. The SZP expression was up-regulated by TGF-beta in both explants and cultured fibroblasts, whereas the expression was slightly down-regulated by IL-1beta. A significant increase in accumulation of SZP protein was also observed in the culture medium of the fibroblasts treated with TGF-beta. CONCLUSIONS: These results suggest that SZP plays an important role in boundary lubrication of mandible condylar cartilage, is synthesized locally within the condyle itself, and exhibits differential regulation by cell mediators relevant to mandibular condyle repairing and pathologies.

Animals↗
PubMed2006

Brain and brawn: parallels in oxidative strength.

Neuronal oxidative stress occurs early in the progression of Alzheimer disease (AD), significantly before the development of the pathologic hallmarks, neurofibrillary tangles, and senile plaques. Study of Down syndrome, cases with autosomal dominant mutation, and sporadic AD all suggest amyloid-beta deposition and hyperphosphorylated tau function as compensatory responses and downstream adaptations to ensure that neuronal cells do not succumb to oxidative damage. Amyloid-beta and tau hyperphosphorylation also define vulnerable muscle cells in sporadic inclusion-body myositis (s-IBM). The role of the structural changes of s-IBM, as in AD, remains to be determined but may mark a critical response yielding a novel balance in oxidant homeostasis.

Adaptation, Physiological↗
PubMed2006

An increase in the serum amylase level in patients after peroral double-balloon enteroscopy: an association with the development of pancreatitis.

BACKGROUND AND STUDY AIMS: Double-balloon enteroscopy (DBE) is a novel technique that allows the enteroscope to be inserted deep into the small intestine. The procedure has been thought to be safe, but cases of acute pancreatitis after peroral DBE have recently been observed. The aim of this study was to confirm the occurrence of hyperamylasemia after peroral DBE. PATIENTS AND METHODS: Peroral DBE was carried out in 13 patients from July 2005 to February 2006. Blood samples were taken before and 3 h after the procedure, and serum pancreatic amylase levels were measured. The patients were also evaluated for pancreatic-type abdominal pain after the procedure. Hyperamylasemia after peroral DBE was defined as an elevation of the serum pancreatic amylase level to more than the upper normal limit and twice the level before the procedure. Pancreatitis was diagnosed on the basis of both pancreatic-type abdominal pain and hyperamylasemia. RESULTS: Hyperamylasemia after peroral DBE occurred in six patients (46.2 %). One of the six patients with hyperamylasemia had pancreatic-type abdominal pain after the procedure and developed acute pancreatitis. The average procedure time was 105 min (range 65 - 155 min) in the patients with hyperamylasemia, and did not significantly differ from that in the group without hyperamylasemia (99 min). CONCLUSIONS: Hyperamylasemia after peroral DBE occurs frequently and may be associated with development of pancreatitis.

Adolescent↗
PubMed2006

Osseous abnormalities of the mandibular condyle: diagnostic reliability of cone beam computed tomography compared with helical computed tomography based on an autopsy material.

OBJECTIVES: We compared the diagnostic reliability of cone beam computed tomography (3DX) and helical computed tomography (helical CT) for the detection of osseous abnormalities of the mandibular condyle, using macroscopic observations as the gold standard. METHODS: Twenty-one temporomandibular joint autopsy specimens underwent imaging with 3DX and helical CT. The specimens were macroscopically evaluated for cortical erosion or osteophytosis and sclerosis. The images were independently assessed for the same osseous abnormalities. Observations with the two imaging modalities were compared with the macroscopic observations using the McNemar test. RESULTS: According to the macroscopic observations, 10 of the 21 mandibular condyles and one fossa showed osseous abnormalities. 3DX detected abnormalities in eight of these condyles and helical CT identified abnormalities in seven, giving a sensitivity of 0.80 for 3DX and 0.70 for helical CT. The specificity of the condyle assessment was 1.0 for both 3DX and helical CT and hence, the accuracy was 0.90 and 0.86, respectively. No significant differences were detected between the 3DX and helical CT for assessment of osseous abnormalities of the mandibular condyle (P=0.286). CONCLUSIONS: The cone beam CT equipment 3DX is a dose-effective and a cost-effective alternative to helical CT for the diagnostic evaluation of osseous abnormalities of the mandibular condyle.

Adult↗
PubMed2006

The thickness of the roof of the glenoid fossa in the temporomandibular joint: relationship to the MRI findings.

OBJECTIVES: The purpose of this study was to clarify the relationship between the thickness of the roof of the glenoid fossa (RGF) and magnetic resonance imaging (MRI) findings of temporomandibular joint (TMJ) disorders (TMDs). METHODS: Eighty-seven patients with symptoms and indications of TMD in one or both TMJs were referred for MRI. Cone-beam CT (3DX) was used to measure the thickness of the RGF at its thinnest point. Linear measurements were made three times on the monitor by three separate investigators and the mean values obtained were used for the statistical analyses. RESULTS: The joints were categorised as normal (70 joints), anterior disc displacement with reduction (ADWR; 53 joints) or anterior disc displacement without reduction (ADWOR; 51 joints). The joint disorders were also categorised into the following subgroups: with osteoarthritis (OA) (21 joints), without OA (153 joints), with disc deformation (33 joints), without disc deformation (141 joints), with joint effusion (JE) (61 joints) and without JE (113 joints). The average minimum thickness of the RGF was 0.85 mm for normal joints, 0.90 mm with ADWR, 0.93 mm with ADWOR, 0.99 mm with OA, 0.87 mm without OA, 0.87 mm with disc deformation and 0.89 mm without disc deformation. There was no significant difference between these figures. There was a significant difference in the thickness of the RGF with (0.97 mm) and without (0.84 mm) JE. CONCLUSIONS: These results suggest that RGF thickness is influenced by JE, but is unaffected by disc position and configuration.

Adolescent↗
PubMed2006

Cytokine profile in synovial fluid from patients with internal derangement of the temporomandibular joint: a preliminary study.

OBJECTIVES: Temporomandibular joint disorders (TMD) comprise a group of chronic painful conditions of mastication in the temporomandibular joint (TMJ). Although the association between TMD and internal derangement of the TMJ is well documented, the functional relevance is still unclear. Increased concentrations of inflammatory mediators have been identified in the synovial fluid of affected patients with TMD, suggesting an underlying degenerative or inflammatory process. The aim of this study was to generate a comprehensive cytokine expression profile in TMD. METHODS: 15 samples from patients with internal derangement of TMJ were analysed using a novel cytokine array that enables the analysis of 79 different cytokines simultaneously. RESULTS: Cytokine levels were correlated with the presence of joint effusion (JE) determined by MRI. In the majority of synovial fluid samples, angiogenin (Ang), fibroblast growth factor (FGF)-9, insulin-like growth factor-binding protein (IGFBP)-3, interleukin (IL)-1alpha, IL-1beta, IL-8, inducible protein (IP)-10, macrophage inflammatory protein (MIP)-1beta, osteoprotegerin (OPG), transforming growth factor (TGF)-beta2, tissue inhibitor of metalloproteinase (TIMP)-1, TIMP-2, tumour necrosis factor (TNF)-beta and vascular endothelial growth factor (VEGF) were detectable. Furthermore, the expression levels of Ang, brain-derived neurotrophic factor (BDNF), FGF-4, FGF-9, IGFBP-2, IL-8, MIP-1beta, OPG, pulmonary and activation-regulated protein (PARC), TGF-beta2, TIMP-2 and VEGF were significantly associated with the presence of JE; among these, nine cytokines (Ang, BDNF, FGF-4, FGF-9, IGFBP-2, MIP-1beta, PARC, TGF-beta2 and TIMP-2) were hitherto not described in TMD. CONCLUSIONS: This study confirmed previous reports of elevated cytokine levels in TMD. Additionally, we identified previously undescribed cytokines that were upregulated and correlated significantly with the presence of JE. We were able to identify novel cytokines that have hitherto not been described in TMD. Strategies targeting the identified cytokines may represent a novel therapy option in TMD.

Adult↗
PubMed2005

The metabolism of hyaluronan in cultured rabbit growth plate chondrocytes during differentiation.

Hyaluronan (HA) is one of the major extracellular matrix components in cartilage. In addition to the biomechanical functions, HA has various important roles in the differentiation of chondrocytes. The purpose of this study was to clarify the nature of HA synthesis during chondrocyte differentiation. Growth plate chondrocytes were isolated from rabbit ribs and cultured in chondrocyte differentiation medium. The amount of HA and HA synthase (HAS) mRNA levels were analyzed for each stage of chondrocyte differentiation by means of high-performance liquid chromatography (HPLC) and real-time PCR, respectively. The distribution of HA in cultured chondrocytes was observed by histochemical staining. The amount of HA, ranging widely in size, was increased substantially during the hypertrophic stage. The expression levels of HAS2 and HAS3 mRNAs were low during the matrix-forming stage. HAS2 mRNA level was substantially enhanced at the pre-hypertrophic stage, whereas HAS3 mRNA level exhibited a slight increase. HAS1 mRNA was not detected. The intensity of HA staining was high around the hypertrophic chondrocytes. These results suggest that HA metabolism in chondrocyte differentiation is regulated by the selective expression of HASs, and HAS2 and the related large size-HA may have a certain association with the hypertrophic changes of chondrocytes.

Animals↗
PubMed2005

Brain oxidation is an initial process in sleep induction.

CNS activity is generally coupled to the vigilance state, being primarily active during wakefulness and primarily inactive during deep sleep. During periods of high neuronal activity, a significant volume of oxygen is used to maintain neuronal membrane potentials, which subsequently produces cytotoxic reactive oxygen species (ROS). Glutathione, a major endogenous antioxidant, is an important factor protecting against ROS-mediated neuronal degeneration. Glutathione has also been proposed to be a sleep-promoting substance, yet the relationship between sleep and cerebral oxidation remains unclear. Here we report that i.c.v. infusion of the organic peroxide t-butyl-hydroperoxide at a concentration below that triggering neurodegeneration (0.1 micromol/100 microl/10 h) promotes sleep in rats. Also, microinjection (2 nmol, 2 microl) or microdialysis (100 microM, 20 min) of t-butyl-hydroperoxide into the preoptic/anterior hypothalamus (POAH) induces the release of the sleep-inducing neuromodulators, nitric oxide and adenosine, without causing neurodegeneration. Nitric oxide and adenosine release was inhibited by co-dialysis of the N-methyl-D-aspartate receptor antagonist, d(-)-2-amino-5-phosphonopentanoic acid (D-AP5; 1 mM), suggesting that glutamate-induced neuronal excitation mediates the peroxide-induced release of nitric oxide and adenosine. Indeed, Ca2+ release from mitochondria and delayed-onset Ca2+ influx via N-methyl-D-aspartate receptors was visualized during peroxide exposure using Ca2+ indicator proteins (YC-2.1 and mitochondrial-targeted Pericam) expressed in organotypic cultures of the POAH. In the in vitro models, t-butyl-hydroperoxide (50 microM) causes dendritic swelling followed by the intracellular Ca2+ mobilization, and D-AP5 (100 microM) or glutathione (500 microM) inhibited t-butyl-hydroperoxide-induced intracellular Ca2+ mobilization and protected POAH neurons from oxidative stress. These data suggest that low-level subcortical oxidation under the control of an antioxidant system may trigger sleep via the Ca(2+)-dependent release of sleep-inducing neuromodulators in the POAH, and thus we propose that a moderate increase of ROS during wakefulness in the neuronal circuits regulating sleep may be an initial trigger in sleep induction.

Adenosine↗
PubMed2005

A study of the in vitro interaction between lidocaine and premedications using human liver microsomes.

OBJECTIVE: To investigate potential interactions between lidocaine (lignocaine) metabolism and premedication drugs, i.e. psychotropic and antianxiety agents (diazepam, midazolam), hypnotics (pentobarbital, thiamylal), depolarizing neuromuscular blocking agents (vecuronium, pancuronium and suxamethonium), an antihypertensive agent (clonidine) and an H2-receptor blocking agent (cimetidine) using human liver microsomes in vitro. METHODS: The interaction effects between lidocaine and premedication were examined using human liver microsomal preparations and monitored for enzyme activity. The lidocaine and its main metabolite (monoethylglycinexylide) were measured by HPLC/UV. RESULTS: Lidocaine metabolism was non-competitively inhibited by midazolam (Ki = 77.6 microM). Thiamylal was a competitive inhibitor of lidocaine metabolism (Ki = 885 microM). Cimethidine, pancuronium and vecuronium weakly inhibited lidocaine metabolism in a concentration-depend manner over the therapeutic range in human liver microsomes. On the contrary, suxamethonium, pentobarbital and clonidine did not inhibit lidocaine metabolism over the therapeutic range in human liver microsomes. CONCLUSION: These results show that the interactions between lidocaine and midazolam and thiamylal are of potential toxicological and clinical significance.

Animals↗
PubMed2005

Cyclic mechanical strain regulates the PTHrP expression in cultured chondrocytes via activation of the Ca2+ channel.

The association between mechanical stimulation and chondrocyte homeostasis has been reported. However, the participation of PTHrP (parathyroid-hormone-related protein) in the mechano-regulation of chondrocyte metabolism remains unclear. We determined whether mechanical stimulation of chondrocytes induces the expression of PTHrP and, further, whether the mechano-modulation of PTHrP is dependent on the maturational status of chondrocytes. Cyclic mechanical strain was applied to rat growth plate chondrocytes at the proliferating, matrix-forming, and hypertrophic stages at 30 cycles/min. Cyclic mechanical strain significantly increased PTHrP mRNA levels in chondrocytes at the proliferating and matrix-forming stages only. The induction of PTHrP was dependent on loading magnitude at the proliferating stage. Using specific ion channel blockers, we determined that mechano-induction of PTHrP was inhibited by nifedipine, a Ca2+ channel blocker. These results suggest that mechanical induction of PTHrP possibly provides the environment for greater chondrocyte replication and matrix formation that would subsequently affect cartilage formation.

Animals↗
PubMed2004

Photoassociation spectroscopy of laser-cooled ytterbium atoms.

We report the photoassociation spectroscopy of laser-cooled ytterbium atoms in an optical trap. We observed more than 90 photoassociation resonances of vibrational levels in the (1)Sigma(+)(u) state, including 80 consecutive series, up to 490 GHz detuning with respect to the atomic resonance. From the resonance frequencies we derived the atomic radiative lifetime of the (6s6p) 1P1 state to be 5.464+/-0.005 ns, which is about 2 orders of magnitude improvement over previous results. We also observed line broadening of resonances, which is ascribed to the predissociation to the triplet states, and estimated the transition probability to be 0.2. Furthermore, we observed the decrease of the photoassociation signal intensity, from which the scattering length is estimated to be equal to or less than 3 nm.

Journal Article↗
PubMed2004

Functional and anatomical effects of hormonally induced experimental prostate growth: a urodynamic model of benign prostatic hyperplasia (BPH) in the beagle.

BACKGROUND: Benign prostatic hypertrophy (BPH) produces a variety of changes in the urodynamic pattern of micturition and is usually associated with high detrusor voiding pressure and poor urine flow-rate. In most previous experimental models, designed to simulate this condition, some degree of obstruction is immediately imposed by the technique employed to produce urethral occlusion. Consequently these models cannot reproduce the gradual onset of obstruction. In the present study a canine prostatic enlargement model, using 5alpha-dihydrotestosterone (DHT) + 17beta-estradiol (E) was adapted in order to produce a more gradual onset of partial obstruction and impaired voiding. MATERIALS AND METHODS: Hormonally induced prostatic enlargement was produced using seven beagles, given DHT 75 mg/day together with E 0.75 mg/day for 28 days via an implantable pump. The functional effects of DHT + E treatment on micturition pressure/flow were measured in the conscious animal. Identical measurements were also made using a separate older group of five beagles with symptoms of BPH. In addition seven beagles similarly instrumented were used as controls. RESULTS: Pressure/flow studies show that DHT + E produced obstructive micturition, characterized by a significantly increased micturition detrusor pressure, from 33.3 +/- 10.5 to 50.8 +/- 10.7 cmH(2)O and significantly decreased low urine flow-rate from 8.6 +/- 2.1 to 6.9 +/- 0.9 ml/sec. Associated with the obstructive micturition, this treatment increased wet prostate weight from 11.9 +/- 2.5 to 31.6 +/- 10.0 g. Prostate volume of the BPH beagles was 29.3 +/- 8.9 g. Morphologic studies show that DHT + E produced epithelial hyperplasia extending focally into the lumen. CONCLUSIONS: Hormonally induced prostate growth produced bladder obstruction, in terms of pressure/flow characteristics, that are analogous to BPH. It is suggested that this type of hormonal treatment can be used to create a model for the study of the effects of controlled increased in prostate growth and the development of BPH on micturition.

Age Factors↗
PubMed2004

Neurofilament proteins in neurodegenerative diseases.

The function of neurofilaments, the major component in large myelinated neurons, is not well understood even though they were discovered as structures over 100 years ago. Recent studies have suggested that neuro-filaments are closely related to many neurodegenerative diseases, such as amyotrophic lateral sclerosis, Parkinson disease Alzheimer disease, and diabetes. Using in vitro assays, cultures and transgenic mice, these studies provided new insights into neurofilament function. The function of each subunit, the relationship of neurofilaments with other cytoskeletal elements and their clinical significance are topics of increasing attention.

Animals↗
PubMed2004

Utility of urinary pyridinoline and deoxypyridinoline ratio for diagnosis of osteoarthritis at temporomandibular joint.

BACKGROUND: Pyridinoline (Pyr) and deoxypyridinoline (Dpyr) collagen cross-links are known markers of bone and cartilage turnover that are found in urine in various diseases. The present study was designed to quantify Pyr and Dpyr levels in urine of patients with osteoarthritis (OA) of the temporomandibular joint (TMJ), and to evaluate whether their concentrations are related to specific pathologic findings in the TMJ. METHODS: Urine samples were obtained from 12 patients with OA of the TMJ and 16 asymptomatic controls, and following appropriate preparation, analyzed by high-performance liquid chromatography (HPLC) and fluorescence spectroscopy for Pyr and Dpyr. RESULTS: The urinary concentration of Pyr and the Pyr to Dpyr (Pyr/Dpyr) ratio were significantly higher (P < 0.05) in OA patients than in the controls (182.2 +/- 86.5 pmol/ml vs. 115.6 +/- 27.9 pmol/ml and 4.00 +/- 1.53 pmol/ml vs. 2.86 +/- 0.97 pmol/ml, respectively). However, the Pyr/Dpyr ratio was not associated with any specific clinical or radiographic findings. CONCLUSION: These findings suggest that the level of Pyr and the Pyr/Dpyr ratio in urine may be a useful diagnostic indicator for intra-articular pathologic changes during TMJ OA.

Adult↗
PubMed2004

Central and peripheral immunoreactivity of melanin-concentrating hormone in hypothalamic obese and lactating rats.

Melanin-concentrating hormone (MCH) is believed to be an important orexigenic peptide mainly localized in the lateral hypothalamic area. Its involvement in the hyperphagia induced by hypothalamic lesions and lactation remains unclear. In this study, we investigated MCH immunoreactivity in the hypothalamus using immunohistochemistry and MCH concentration in the peripheral circulation using an enzyme immunoassay in rats with a lesion in the ventromedial hypothalamus or the paraventricular nucleus, and in lactating rats. Bilateral lesions of the ventromedial or paraventricular nuclei were performed using an electrolytic method. Quantification of immunoreactivity by image analysis revealed that the number and mean staining intensity of MCH-immunoreactive neurones in the lateral hypothalamic area and the zona incerta were significantly decreased by both types of lesions compared to sham controls, whereas circulating MCH concentration was not significantly different on day 7 postlesion. By contrast, in lactating rats on days 11-12 postpartum, the expression of MCH in the lateral hypothalamic area and the zona incerta was significantly increased compared to nonlactating controls. Circulating MCH concentration was not changed in lactating rats. These results suggest that hyperphagia induced by lactation, but not hypothalamic lesion, might be induced by excessive expression of MCH in the lateral hypothalamic area and the zona incerta.

Animals↗
PubMed2004

Effects of TGF-beta on hyaluronan anabolism in fibroblasts derived from the synovial membrane of the rabbit temporomandibular joint.

Hyaluronan (HA) synthesis in the synovial membrane is affected by various chemical mediators. It is hypothesized that transforming growth factor-beta 1 (TGF-beta 1) would be a mediator to modulate HA synthesis in cultured synovial membrane fibroblasts of the temporomandibular joint (TMJ). Fibroblasts were extracted from the TMJ synovial membrane of four-week-old Japanese white rabbits. The amount of HA and expression levels of HA synthase (HAS) mRNAs induced by TGF-beta 1 treatment were analyzed by means of high-performance liquid chromatography and real-time polymerase chain-reaction, respectively. Both medium and large amounts of HA were enhanced by the stimulation of TGF-beta 1. HAS2 mRNA expression was enhanced 13-fold after six-hour stimulation with TGF-beta 1 (10 ng/mL), whereas HAS3 mRNA expression was not changed significantly. These results suggest that TGF-beta 1 enhances the expression of HAS2 mRNA in the TMJ synovial membrane fibroblasts and may contribute to the production of high-molecular-weight HA in the joint fluid.

Animals↗
PubMed2004

Single air contrast arthrography for temporomandibular joint disorder using limited cone beam computed tomography for dental use.

MRI has the problem of artefacts caused by metal or body motion and is also incompatible for patients with claustrophobia. Arthrography is invasive and involves the risk of perforation or allergy to a contrast medium. This report discusses a patient with temporomandibular joint (TMJ) disorder who required soft tissue imaging of the TMJ. As she had claustrophobia and a reaction to iodine, air contrast arthrography and pumping manipulation therapy using limited cone beam computed tomography for dental use (3DX) was performed. We conclude that the 3DX examination method used in the study is practical as a diagnostic procedure and thus recommend this method to be used for patients with TMJ disorder in the presence of iodine contraindication.

Air↗