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Biomedical subjects

Jinichi Fukuda

Publications and source records attributed to Jinichi Fukuda.

12 recordsLinked to original sources
PubMed2006

Biomechanical evaluation of different types of rigid internal fixation techniques for subcondylar fractures.

PURPOSE: The aim of this study was to evaluate the biomechanical stability of various internal fixation systems for subcondylar fractures. MATERIALS AND METHODS: Eighteen identical synthetic mandibles were used. Left condylar processes were cut to mimic perpendicular subcondylar fracture and right sides were mimicked oblique subcondylar fracture. The fixation systems used included single 4-hole mini adaptation plate, double fixation with the same plates, single 4-hole mini dynamic compression plate (DCP), Eckelt lag screw system, Wurzburg lag screw plate system and double 4-hole biodegradable miniplates made of poly L-lactide (PLLA). In oblique fractures, one of the screws fixing plates was used bicortically through bone fragments. The loading vector simulated physiologic forces to the condyle on biting with servohydraulic testing machine until failure was reached. Load-displacement curve, maximum load for failure, and stiffness were measured. RESULTS: In perpendicular fracture, double adaptation plate showed the highest level of tolerance load followed by Eckelt lag and double PLLA plate. In stiffness, double adaptation plate and Eckelt lag screw showed higher level of stiffness, whereas double PLLA was almost at the same level of single DCP. In oblique fracture, double adaptation plate showed the highest strength. CONCLUSIONS: In this laboratory setting, double adaptation plates fixation proved to have superior biomechanical stability in both fracture conditions. Eckelt lag screw showed good stability in the perpendicular fracture, however, it was weak in the oblique fracture.

Biomechanical Phenomena↗
PubMed2006

Relationship between TNF-alpha and TUNEL-positive chondrocytes in antigen-induced arthritis of the rabbit temporomandibular joint.

BACKGROUND: Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate biotin nick end-labeling (TUNEL) staining is a widely accepted method for the detection of DNA fragmentation in nuclei of apoptotic cells. Tumor necrosis factor (TNF)-alpha is closely associated with changes in condylar cartilage and modulates apoptosis in various tissues including cartilage. The aim of this study was to investigate the relationship between apoptotic chondrocytes and TNF-alpha in a rabbit model of arthritis. METHOD: Unilateral temporomandibular joint (TMJ) arthritis was induced in 20 adult New Zealand White rabbits. From 1 day to 6 weeks after the induction of arthritis, immunohistochemical analysis for TNF-alpha and TUNEL was performed. RESULTS: In condylar cartilage, TNF-alpha-positive cells and TUNEL-positive cells were localized together. TNF-alpha-positive chondrocytes seemed to precede TUNEL-positive cells. CONCLUSIONS: The results of the present study suggest that TNF-alpha may be involved in apoptosis and/or apoptotic necrosis of chondrocytes as TMJ arthritis progresses from the acute to chronic stage.

Animals↗
PubMed2004

IL-1 beta, IL-1 receptor antagonist and soluble type II IL-1 receptor in synovial fluid of patients with temporomandibular disorders.

Among the members of the interleukin-1 (IL-1) family, IL-1 beta, which is a major agonist, has been detected in synovial fluid (SF) of the temporomandibular joint (TMJ) of patients with temporomandibular joint disorders (TMD). However, there is little knowledge regarding suppressive molecules, such as IL-1 receptor antagonist (IL-1ra) and the soluble form of type II IL-1 receptor (sIL-1RII), in TMD patients. The aim of this study was to investigate the levels of IL-1 beta, IL-1ra and sIL-1RII in the TMJ SF of patients with TMD and their relationship. Fifty-two SF samples from TMD patients and nine samples from asymptomatic volunteers were examined. Detected levels of IL-1 beta and sIL-1RII were significantly higher in the TMD group compared with the volunteer group. There was no significant difference in IL-1ra levels between the TMD and volunteer groups. The IL-1 beta/IL-1ra ratio in the TMD group, however, was higher than that in the volunteer group. In the TMD group, positive correlations were found between IL-1 beta and IL-1ra, IL-1ra and sIL-1RII, and IL-1 beta and sIL-1RII. In addition to increased IL-1 beta, development of TMD may also lead to decreased IL-1ra and increased sIL-1RII in response to increasing IL-1.

Adolescent↗
PubMed2004

A decrease in the molecular weight of hyaluronic acid in synovial fluid from patients with temporomandibular disorders.

BACKGROUND: The molecular weight (MW) of hyaluronic acid (HA) in joints generally declines in inflammatory arthritis. As inflammation exists in certain temporomandibular disorders (TMD), we measured the MW of HA in synovial fluid (SF) recovered from patients with TMD and compared it with that from normal controls. METHODS: Synovial fluid was obtained from patients with TMD (21 TMJs) and normal controls (5 TMJs). The MW of HA was measured using high-performance liquid chromatography (HPLC). RESULTS: In the controls, the MW of HA in SF exceeded the detection limit, 3000 kDa. In contrast, 19 (90.5%) of 21 SF samples from patients showed a decreased MW of HA. The median MW of HA (1570 kDa) in TMD was significantly lower than that in the controls (P < 0.01). CONCLUSION: The MW of HA in SF from patients with TMD is decreased.

Adolescent↗
PubMed2004

Involvement of tumor necrosis factor-alpha and interleukin-8 in antigen-induced arthritis of the rabbit temporomandibular joint.

BACKGROUND: In temporomandibular joint (TMJ) arthritis, knowledge is limited about the source of the inflammatory mediators. The aim of this study was to investigate the immunohistochemical role of tumor necrosis factor-alpha (TNF-alpha) and interleukin-8 (IL-8) in the development of the antigen-induced arthritis of the rabbit TMJ. METHODS: Unilateral TMJ arthritis was induced in 28 adult rabbits. From 6 h to 6 weeks after induction of arthritis, the topology of TNF-alpha and IL-8 was observed. RESULTS: Positive reaction for TNF-alpha of synovial cells was observed within 3 days after induction and at 3 weeks after induction. TNF-alpha positive vascular endothelial cells and chondrocytes were identified throughout the observation period. IL-8 was detected only during the acute stage. CONCLUSIONS: The cytokines TNF-alpha and IL-8 were observed in specific cells depending on the stage. TNF-alpha was particularly related with angiogenesis and cartilage destruction and IL-8 was involved in the acute stage of inflammation.

Animals↗
PubMed2004

Morphological evaluation of changes in velopharyngeal function following maxillary distraction in patients with repaired cleft palate during mixed dentition.

OBJECTIVE: To describe the morphological changes of nasopharyngeal components after maxillary distraction and clarify whether the morphological characteristics are related to velopharyngeal function (VPF). DESIGN: Perceptual judgments of hypernasality and nasendoscopy were performed before and after treatment. Lateral cephalograms were obtained to describe the morphological changes. SETTING: Department of Oral and Maxillofacial Surgery, Miyazaki Medical College, Miyazaki, Japan. PARTICIPANTS: Nine patients with repaired cleft palate in the mixed dentition stage underwent maxillary distraction using a face mask and an intraoral fixed appliance system. OUTCOME MEASURES: The severity of hypernasality, velopharyngeal insufficiency, and measurements such as pharyngeal depth, velar length, and the rotation of the palatal plane were evaluated. RESULTS: Increase in pharyngeal depth was not always proportional to the amount of advancement. It depended on the posture of the posterior pharyngeal wall and the rotation of palatal plane. CONCLUSION: Cephalometric measurements of the nasopharynx before and after surgery confirmed subsequent changes in VPF. These were suggested to be useful in predicting future VPF. When performing maxillary distraction in patients with cleft palate in the mixed dentition stage, and when velopharyngeal closure is found to occur by velar contact against the hypertrophied adenoid, patients should be counseled about risks of subsequent deterioration in their speech before surgery.

Adenoids↗
PubMed2003

Growth/differentiation factor-5 induces growth arrest and apoptosis in mouse B lineage cells with modulation by Smad.

Bone morphogenetic proteins, including growth/differentiation factor-5 (GDF-5), are multifunctional cytokines. Recent studies of intracellular signal transduction mechanisms for the transforming growth factor-beta superfamily have focused on Smad proteins. However, scant attention has been given to the mechanism by which GDF-5 exerts its negative growth effect on immunological competent cells. In the present study, we demonstrated that GDF-5 induced cell cycle arrest in the G1 phase before the appearance of apoptosis in mouse B cell hybridoma HS-72 cells, while the ectopic expression of Smad6 and Smad7 in HS-72 cells suppressed the GDF-5-induced G1 cell cycle arrest by abolishing the expression of p21(CIP-1/WAF-1) and hypophosphorylation of retinoblastoma protein. Moreover, we found that Smad6 and Smad7 suppressed GDF-5-induced apoptosis in HS-72 cells. These findings indicated that Smad6 and Smad7 exhibit inhibitory effects toward GDF-5-mediated signaling in B lineage cells.

Animals↗
PubMed2003

Prevalence of hepatitis viral infection in dental patients with impacted teeth or jaw deformities.

OBJECTIVE: The prevalence of infection with hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis G virus (HGV), and transfusion-transmitted viruses (TTV) was evaluated in patients with impacted teeth or jaw deformities. STUDY DESIGN: Of 486 patients, 268 had serum samples available for retrospective TTV DNA and HGV RNA assays. In addition, the sera of 404 patients were assayed for HB surface antigen and the sera of 340 were assayed for HCV antibody. RESULTS: HGV RNA was detected in 3 of 268 patients (1.1%), and TTV DNA was detected in 60 of 268 (22.4%). Of 404 patients, 3 had HB surface antigens (0.7%). Furthermore, 13 of 340 were HCV-seropositive (3.8%). The rate of infection was similar between patients with impacted teeth and those with jaw deformities, respectively, as follows: 1.1% versus 0%, respectively, for HBV prevalence; 4.1% versus 3.2% for HCV prevalence; 1.8% versus 0% for HGV prevalence; and 22.9% versus 21.4% for TTV prevalence. CONCLUSIONS: Universal precautions to prevent hepatitis and TTV infection during oral surgical procedures are important.

Adult↗
PubMed2002

Hypercalcemia associated with parathyroid hormone-related protein at the terminal stage of uncomplicated squamous cell carcinoma in the head and neck region.

BACKGROUND: Parathyroid hormone-related protein (PTHrP) is mainly responsible for hypercalcemia in squamous cell carcinomas (SCCs). METHODS: We retrospectively checked the appearance of hypercalcemia among 33 patients who died with head and neck SCC. Serum concentrations of C-terminal region of PTHrP (C-PTHrP) were measured in 15 of them. The intracellular PTHrP expression was immunohistochemically stained in 42 SCC sections obtained from the 33 before the appearance of hypercalcemia. RESULTS: Hypercalcemia appeared in 24 of the 33, and increased serum C-PTHrP levels were confirmed in 11 of 12 hypercalcemic patients. PTHrP was identified in all SCC sections, and a stronger intensity than in normal squamous epithelia was observed in 50% of those obtained within 1 year before the onset of hypercalcemia. CONCLUSION: A high incidence of PTHrP-induced hypercalcemia was shown among patients dying with head and neck SCCs. The intracellular increase in PTHrP might be observed preceding hypercalcemia.

Adult↗
PubMed2002

Prevalence of hepatitis virus infection in association with oral diseases requiring surgery.

OBJECTIVE: We evaluated the prevalence of hepatitis virus infection in a large population of patients in terms of diseases requiring oral surgery. DESIGN: Retrospective case survey. SUBJECTS AND METHODS: Prevalence of hepatitis B and C virus (HBV, HCV) infection were compared between oral diseases such as inflammation, cysts, cancer, trauma, benign tumors, impacted teeth, or jaw deformity in dental inpatients (n = 5830) with adjustment for age, gender, and history of surgery. RESULTS: Of 4402 inpatients, 94 had HB surface(s) antigen (2.1%), while 151 of 2613 were seropositive for HCV (5.8%). Prevalences of HBs antigen and HCV antibody exceeded those in the general population. HBs antigen was more prevalent in patients with benign oral tumors than in patients with impacted teeth, whether or not adjustment was made for age (odds ratios, 4.246 and 5.055 with and without age adjustment, respectively; P < 0.05). On the other hand, HCV antibody was more prevalent in patients with oral cancer than in those with impacted teeth before adjustment for age (odds ratios, 2.433; P < 0.05), but this difference was reversed with age adjustment (odds ratios, 0.443; P < 0.05). CONCLUSION: HBs antigen was more prevalent in patients with benign oral tumors, while HCV antibody was higher in patients with oral cancer. However, this increased incidence of HCV antibody apparently was a reflection of age. HCV infection may not have an etiologically important association with oral cancer.

Adult↗
PubMed2002

Immunohistochemical study of interleukin-1beta and interleukin-1 receptor antagonist in an antigen-induced arthritis of the rabbit temporomandibular joint.

BACKGROUND: In temporomandibular joint (TMJ) arthritis, there is limited knowledge of the relationship between interleukin-1beta (IL-1beta) and interleukin-1 receptor antagonist (IL-1ra), as well as the source of these cytokines. We investigated the development of an antigen-induced arthritis in the rabbit TMJ immunohistochemically. METHODS: Unilateral TMJ arthritis was induced in 32 adult New Zealand White rabbits. From 6 h to 12 weeks after induction of arthritis, topology of IL-1beta and IL-1ra were observed. RESULT: The acute stage of induced arthritis lasted for one week after induction, thereafter it became chronic. In the early phase of the acute stage, infiltrating inflammatory cells, as well as synovial cells, produced IL-1beta and IL-1ra. In the late phase of the acute stage, the main source of these cytokines was subsynovial fibroblasts. In this phase of arthritis, IL-1beta and IL-1ra did not appear to be produced by synovial cells. From the early to intermediate phase of the chronic stage, proliferating synovial cells produced IL-1beta and IL-1ra. In this phase of the arthritis, these cytokines were also observed in a cluster formation in chondrocytes. CONCLUSION: This arthritis model shows a staging of the joint inflammation process with time. IL-1beta and IL-1ra are produced by a certain kind of cells depending on the stage of inflammation.

Acute Disease↗