Biomedical subjects

T Iizuka

Publications and source records attributed to T Iizuka.

At least 37 records · Page 2Linked to original sources

PubMed2002

The expression of cyclooxygenase-2 in human temporomandibular joint samples: an immunohistochemical study.

The aim of this investigation was to evaluate the immunohistochemical expression of cyclooxygenase-2 (COX-2) in the temporomandibular joint (TMJ) and to compare it with that control specimens. Expression of COX-2 in the TMJ disc and the synovial membrane in 26 human TMJ samples (internal derangement of TMJ; n=16, and control; n=10) was measured by an immunohistological technique using paraffin-embedded tissue and specific antihuman COX-2 polyclonal antibody. There were obvious distinction of COX-2 immunoreactivity between the control specimens and internal derangement cases, in the region of posterior and/or anterior loose connective tissues. In particular, intensive COX-2 expression was detected in the synovial membrane of internal derangement cases. The findings of the present study suggest that COX-2 might be an important mechanism regulating inflammation in the synovial membrane with internal derangement of TMJ.

Adult↗

PubMed2002

Regeneration of defects in the articular cartilage in rabbit temporomandibular joints by bone morphogenetic protein-2.

The purpose of this study was to investigate the therapeutic use of recombinant human bone morphogenetic protein-2 (rhBMP-2) in internally deranged temporomandibular joints (TMJ). Defects (2 mm in diameter) were created in the surface of the condylar head. Lyophilized rhBMP-2 with collagen as the carrier was implanted in the defects in different doses: rhBMP-2 15 microg (n = 5); rhBMP-2 3 microg (n = 5); rhBMP-2 0.6 microg (n = 5). In the two control groups, the defects were either filled with collagen alone (n = 5) or left untreated (n = 5). Three weeks postoperatively the sites of defects were examined under light microscopy. In the 15 micromg and the 3 microg groups, new cartilage had filled the defects; endochondral ossification was also found deep within the defect. In the 0.6 microg group, fibrous tissue was proliferating in most areas of the defect, although cartilage was also found in some parts. In the two control groups, there was either soft tissue repair only or no evidence of tissue repair. These findings suggest that BMP-2 could stimulate the repair of defects in the articular cartilage of the mandibular condyle head during the 3 weeks postoperatively. To observe the progress of endochondral ossification in more detail, it may be necessary to extend the experiment for a longer period of time. However, this study supports the contention that BMP-2 may be useful in the regeneration of cartilage in TMJ disease.

Animals↗

PubMed2002

Evaluation of the pathophysiology of odontogenic maxillary sinusitis using bone scintigraphy.

The inflammatory changes in the maxillary sinus mucosa and wall (mucosal and bony lesions) were evaluated to identify the pathophysiology of odontogenic maxillary sinusitis. Out of 80 patients who underwent CT, 32 patients were examined using single photon emission computerized tomography (SPECT) bone scintigraphy (bone SPECT) with 99mTc-hydroxymethylene-diphosphonate. Mucosal and bony lesions were evaluated morphologically on both images. SPECT data were used to assess the bone activity by calculating the count ratios of the causative alveolar process over the cervical vertebrae. The relationships with clinical symptoms, mucosal changes around the maxillary ostium (ostial lesions), and radiolucencies around the causal teeth (periapical lesions) were assessed. Bone SPECT showing the causal site was valuable for aiding a definitive diagnosis. Mucosal lesions tended to exceed bony lesions horizontally and vertically. Bony lesions tended to extend posteriorly and then anteriorly. The vertical extent of mucosal lesions and the horizontal and vertical extent of bony lesions were correlated with the presence of facial symptoms, ostial lesions, and periapical lesions. Bone activity was significantly correlated with the horizontal and vertical extent of mucosal lesions, horizontal extent of bony lesions, and presence of infraorbital symptoms, ostial lesions, and periapical lesions. Bone activity caused by alveolitis affects the pathophysiology of this disease.

Alveolar Process↗

PubMed2002

A recurrent case of odontogenic ghost cell tumour of the mandible.

Odontogenic ghost cell tumour (OGCT), also referred to as dentinogenic ghost cell tumour, is an extremely rare tumour classified as a neoplastic variant of calcifying ondontogenic cyst (COC). To date, only 13 cases of OGCT arising in the maxilla or mandible have been reported. We describe an OGCT that recurred after segmental resection of the mandible in a 59-year-old man. Histopathological examination revealed tumour invasion of the surrounding cortical bone, areas containing numerous calcifying flaky cell nests, and dentinoid matrix near epithelial cell nests. No atypical mitosis was found. There has been no evidence of recurrence or metastasis in the 4 years after operation.

Dentin↗

PubMed2002

Factors influencing the therapeutic effect of muscle afferent block for oromandibular dystonia and dyskinesia: implications for their distinct pathophysiology.

Oromandibular dystonia (OMD) is a focal dystonia manifested by involuntary masticatory and/or lingual muscle contractions. Muscle afferent block (MAB) by injecting anaesthetic and alcohol intramuscularly is recently used for the treatment of OMD. To study the factors affecting the efficacy of MAB, 44 patients with OMD were treated by local injection of lidocaine and ethanol. They were divided into four groups (spastic, rhythmic, dyskinetic, and task-specific) according to the pattern of incisal movement and involuntary contraction. We used a clinical scaling protocol in terms of four parameters (mastication, speech, pain, and discomfort) to evaluate the change of symptoms objectively. The relationship of improvement in clinical scores with various parameters was assessed statistically. The overall objective improvement was 60.2 +/- 29.5%. The scores decreased significantly (P<0.0001, paired t-test) after MAB. The maximal incisal velocity significantly correlated inversely with the clinical improvement, and MAB was particularly effective for spastic contraction. Dyskinetic and rhythmic groups showed variable and significantly less improvements than the spastic group. MAB is highly effective for OMD, but not for the patients with dyskinetic symptoms. The jaw movement pattern is an important factor for predicting the outcome. The difference in the response to MAB in OMD and oral and/or orofacial dyskinesia suggests the distinct pathophysiology between the two.

Adolescent↗

PubMed2002

Maxillofacial injuries related to work accidents: a new concept of a hospital-based full electronic occupational trauma surveillance system.

The objective of this study was to investigate the occurrence of occupational maxillofacial injuries using a newly installed relational database. Twenty-six injuries were identified out of 28,624 patients admitted to the emergency unit during a 12 month period. Falls from height or being struck by moving objects were common causes of these injuries. Two-thirds of those identified were construction workers. This paper demonstrates the power of modern databases to identify specific occurrences that may provide the basis for prevention in the future.

Accidents, Occupational↗

PubMed2001

The time course study of osteoinduction by bone morphogenetic protein-2 via adenoviral vector.

We evaluated the time course of osteoinduction by an adenoviral vector, AxCAOBMP-2, in normal rats (Group I) and 2 immunosuppressed groups (Groups II and III). Immunosuppression was induced by 125 mg/kg of cyclophosphamide injected intraperitoneally the day before vector injection. Groups I and III received a high dose of AxCAOBMP-2 (25 microl; 8.75 x 10(8) pfu) and Group II a low dose (5 microl; 1.75 x 10(8) pfu). Each dose of AxCAOBMP-2 was injected into the right calf muscle of rats. On days 7, 14 and 21 postinjection, the osteoinducive activity in each group was investigated radiologically, histologically, immunohistochemically and biochemically. Osteoinduction was observed only in Groups II and III on days 14 and 21. The activity of osteoinduction in Group III was higher than that in Group II. There was little difference in the expression of LacZ between Groups I and III on day 3. However, there was a marked difference in BMP-2 protein expression between Groups I and III on day 7 postinjection. We speculated that the reason for this was that most of the infected cells were eliminated by the immune system of the host from days 3 to 7. These results suggest that gene therapy with AxCAOBMP-2 under transient immunosuppression may be useful for bone reconstruction.

Adenoviridae↗

PubMed2001

Right hepatic duct emptying into the cystic duct: report of a case.

BACKGROUND: Anomalous insertion of the right hepatic duct into the cystic duct is a rare anatomic variation. At this writing, only nine cases have been reported in the literature. In the patients presenting with this anomaly, the surgeon may accidentally transect the right hepatic duct during cholecystectomy. METHODS: We encountered a case of anomalous insertion of the right hepatic duct into the cystic duct, which was clearly demonstrated in the intraoperative cholangiography during laparoscopic cholecystectomy. RESULTS: As the half-cut point of the cystic duct happened to be on the gallbladder side of the cystic duct, cholecystectomy was accomplished laparoscopically. CONCLUSIONS: In anomalous insertion of the right hepatic duct into the cystic duct, hepatic duct transection could happen. Preoperative precise evaluation of the biliary duct, awareness of potential biliary variations, and identification of all anatomic structures before ligation and division were essential to prevent bile duct injury.

Aged↗

PubMed2001

CD98 induces LFA-1-mediated cell adhesion in lymphoid cells via activation of Rap1.

CD98 is a multifunctional heterodimeric membrane protein involved in the regulation of cell adhesion as well as amino acid transport. We show that CD98 cross-linking persistently activates Rap1 GTPase in a LFA-1-dependent manner and induces LFA-1/ICAM-1-mediated cell adhesion in lymphocytes. Specific phosphatidylinositol-3-kinase (PI3K) inhibitors suppressed both LFA-1 activation and Rap1GTP generation, and abrogation of Rap1GTP by retroviral over-expression of a specific Rap1 GTPase activating protein, SPA-1, totally inhibited the LFA-1/ICAM-1-mediated cell adhesion. These results suggest that CD98 cross-linking activates LFA-1 via the PI3K signaling pathway and induces accumulation of Rap1GTP in a LFA-1-dependent manner, which in turn mediates the cytoskeleton-dependent cell adhesion process.

Androstadienes↗

PubMed2001

Quantitative evaluation of the enhanced green fluorescent protein displayed on the cell surface of Saccharomyces cerevisiae by fluorometric and confocal laser scanning microscopic analyses.

The number of foreign protein molecules expressed on the cell surface of the budding yeast Saccharomyces cerevisiae by cell surface engineering was quantitatively evaluated using enhanced green fluorescent protein (EGFP). The emission from EGFP on the cell surface was affected by changes in pH. The amount of EGFP on the cell surface, displayed as alpha-agglutinin-fusion protein under control of the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) promoter, was determined at the optimum pH of 7.0. The fluorometric analysis and the image analysis by confocal laser scanning microscopy (CLSM) showed a similar number of molecules displayed on the cell surface, demonstrating that 10(4)-10(5) molecules of alpha-agglutinin-fused molecules per cell were expressed. Furthermore, the amount of fluorescent protein expressed on cells harboring a multicopy plasmid was three to four times higher than that on cells harboring the gene integrated into the genome.

Arabidopsis↗

PubMed2001

Effect of coffee consumption on bone metabolism.

The effects of coffee on bone metabolism are still controversial, although several studies have suggested that caffeine and/or heavy coffee consumption is associated with a significant increase in risk of fracture, osteoporosis, and periodontal disease. Therefore, we sought to clarify the relationship between coffee consumption and bone metabolism using male Wistar rats. Forty-eight male Wistar rats were assigned to three treatment groups including a control-diet group (control, n = 16, coffee-free diet), a 0.62% coffee-diet group (low caffeine, n = 16, diet supplemented with 6.2 g/kg of the control diet), and a 1.36% coffee-diet group (high caffeine, n = 16, diet supplemented with 13.6 g/kg of the control diet), and animals were maintained on an experimental diet for 140 days. Although caffeine in serum was not detected in rats fed the control diet, low-intake coffee for 140 days led to an increase in caffeine concentration to 0.53 +/- 0.11 microg/mL and high-intake coffee led to an increase of 1.77 +/- 0.22 microg/mL. No significant differences in body weight change, serum and urinary biochemical markers of bone metabolism, and bone histomorphometry were found between the coffee-diet groups and the control-diet group, except that urinary phosphorus excretion after 140 days of both coffee diets was significantly increased compared with controls (p < 0.05). In addition, the coffee diets were not associated with differences in tumor necrosis factor-alpha and interleukin-6, which have been implicated in the pathogenesis of bone loss together with interleukin-1beta. In conclusion, the present study strongly indicates that coffee does not stimulate bone loss in rats.

Amino Acids↗

PubMed2001

The GOR gene product cannot cross-react with hepatitis C virus in humans.

GOR (GOR47--1) is an epitope thought to be a host-derived antigen cross-reactive with hepatitis C virus (HCV) since it was isolated from a cDNA library of host animals reactive with sera of HCV-positive patients. An enzyme immunosorbent assay (ELISA) using this epitope as antigen is of sufficient sensitivity and specificity for screening patients with HCV. However, the relationship between GOR47--1 epitope and autoimmune phenomena associated with HCV infection or autoimmune hepatitis is controversial. Here we isolated the human GOR gene and found that the GOR47--1 epitope was not translated in humans due to a single base replacement from chimpanzee. Furthermore, we found some patients who had antibodies against another epitope, which is translated (GOR1--125) in humans, although there was no correlation between the existence of anti-GOR47--1 or anti-GOR1--125 Ab and autoimmune phenomena. Serum IgG levels did not influence the titres of these antibodies. Taken together with the results of several other studies, our finding that the GOR47--1 epitope cannot be translated into a protein suggests that there is little relationship between autoimmunity and the GOR gene product in human beings. We also discuss here the possible mechanism of cross-reactivity between HCV and the GOR gene product.

Amino Acid Sequence↗

PubMed2001

Involvement of mucosal addressin cell adhesion molecule-1 (MAdCAM-1) in the pathogenesis of granulomatous colitis in rats.

Although increased expression of mucosal addressin cell adhesion molecule-1 (MAdCAM-1) has been demonstrated in inflammatory sites of various diseases, its role in colitis remains unknown. In this study, we examined whether MAdCAM-1 is involved in the pathogenesis of granulomatous colitis induced by peptidoglycan-polysaccharide (PG-PS). Experimental colitis was induced by intramural injection of PG-PS to rat colon. After 3 weeks the colon was removed and the mucosal inflammation was assessed. The area of MAdCAM-1-positive venules and the subsets of infiltrating cells were determined in colonic mucosa by immunohistochemistry. In another experiment, monoclonal antibody against MAdCAM-1 was administered intraperitoneally to examine its attenuating effect on colitis. The intramural injection of PG-PS induced significant colonic inflammation with granuloma formation. The submucosa was drastically thickened with the infiltration of CD4 positive lymphocytes and ED-1 positive macrophages. Intense MAdCAM-1 expression was observed on endothelium of the submucosal venules in inflamed mucosa. Administration of anti-MAdCAM-1 antibody significantly attenuated the PG-PS-induced colonic damage and cell infiltration. Enhanced expression of MAdCAM-1 was demonstrated in venular endothelium of the inflamed colon in PG-PS-induced colitis. The attenuating effect of anti-MAdCAM-1 suggests the importance of the MAdCAM-1-dependent process in the formation of chronic granulomatous colitis.

Animals↗

PubMed2001

Variation of heads of lateral pterygoid muscle and morphology of articular disc of human temporomandibular joint--anatomical and histological analysis.

To grasp the documented evidences available regarding the cause of the anteriorly displaced human temporomandibular joint (TMJ) disc. With 20 specimens of human TMJ from cadavers, at first the number of heads of lateral pterygoid muscle (LPM) bundles were analysed with macroanatomical method. Secondary histological procedure with haematoxyline and eosine staining and orceine staining were carried out for the same specimens. Macroscopically, in 13 specimens an upper and a lower head of the LPM were present. In the other seven specimens, not only an upper and a lower head, but also a third inner head of the LPM covered with a separate fascia was observed. Histochemically, the specific localization of certain bundles of thick elastic fibres in the antero-medial parts of the anteriorly displaced deformed TMJ disc were observed.

Adipose Tissue↗

PubMed2001

The distribution of cyclooxygenase-1 in human temporomandibular joint samples: an immunohistochemical study.

Cyclooxygenase-1,2 (COX-1,2) or prostaglandin (PG) H synthase, is the first enzyme of the pathway in which arachidonic acid is oxidized to PGs. Thus, we examined the expression of COX-1 in 16 human temporomandibular joint (TMJ) samples with internal derangement and in 10 control specimens by an immunohistological technique using paraffin-embedded tissue and specific antihuman COX-1 polyclonal antibody. There was obvious distinction of COX-1 immunoreactivity between the control specimens and internal derangement cases, at the endothelial cells and fibroblasts, in the region of posterior and/or anterior loose connective tissues and synovial membrane. The findings of the present study suggest that COX-1 might be an important mechanism for maintaining normal homeostasis at the endothelial cells and fibroblasts with internal derangement of TMJ.

Adult↗

PubMed2001

Localization of keratan sulphate and chondroitin-6-sulphate on the anteriorly displaced human temporomandibular joint disc--histological and immunohistochemical analysis.

The aetiology of temporomandibular joint (TMJ) disc displacement has been investigated using human post-mortem material. Twenty TMJ specimens were used for a histological procedure with haematoxylin and eosin staining and orcein staining. Immunohistological analysis with chondroitin-6-sulphate and keratan sulphate was also carried out on the same specimens. Immunohistochemically, the specific localization of chondroitin-6-sulphate and keratan sulphate in the antero-medial parts of the anteriorly displaced deformed TMJ disc, which may be load-bearing areas, was observed. Orcein staining revealed that specific elastic fibres pulling the anterior band and stretching the disc continuously, may be an important factor in disc displacement. On the basis of these results, we were able to propose a significant new hypothesis for the aetiology of disc displacement.

Adult↗

PubMed2001

Condylar process fractures in children: a follow-up study of fractures with total dislocation of the condyle from the glenoid fossa.

PURPOSE: The purpose of this study was to investigate the long-term clinical and radiologic outcome of nonsurgically treated, dislocated condylar fractures sustained during childhood. PATIENTS AND METHODS: Dislocated condylar process fractures were diagnosed in 34 children aged 15 years or younger from 1980 to 1991. Of these, 26 had been treated nonsurgically and were asked to participate in a follow-up examination. Eighteen patients, representing 69% of the total sample, took part in the study. All patients underwent a clinical investigation with special emphasis on temporomandibular joint (TMJ) function. The patients also underwent a radiologic investigation, focusing on fracture remodeling and symmetry of the mandible. RESULTS: After a follow-up period ranging from 4.8 to 16.4 years (mean, 8.6 years), 56% had some subjective symptoms, and 72% had some objective signs of TMJ dysfunction. In general, however, the symptoms and signs of dysfunction were very slight. No correlation was observed between the method of nonsurgical treatment and the clinical results. Radiologic investigation showed incomplete remodeling (76.5%) and asymmetry of the mandible (64.7%) in most patients. The asymmetry was slight, however, and could not be observed clinically. CONCLUSIONS: Conservative treatment of dislocated condylar process fractures in children results in satisfactory long-term outcome of jaw function despite a high frequency of radiologically noted aberrations. Soft diet with immediate mobilization seems to be the treatment of choice.

Adolescent↗

PubMed2001

Effect of hyperbaric oxygenation on bone induced by recombinant human bone morphogenetic protein-2.

We examined the effect of hyperbaric oxygen (HBO) therapy on the osteoinductive activity of recombinant human bone morphogenetic protein-2 (rhBMP-2), 5mg of which was implanted into the calf muscle of rats using atelopeptide type I collagen as a carrier. Thirty Wistar rats were divided equally to be given HBO or act as controls. New bone formation was measured radiographically, biochemically, and histol ogically 3, 7, and 21 days after implantation. In both groups, new bone formation was found on day 21. However, there was significantly more new bone in the HBO group. In the HBO group, cartilage was present at the outer edge of the implanted material on day 7. On days 7 and 21, the local tissue alkaline phosphatase activity and calcium content in the HBO group were significantly greater than in the control group. These results suggest that HBO accelerated the activity and rate of osteoinduction by rhBM P-2.

Alkaline Phosphatase↗