PubMed Health⌕ Search

Biomedical subjects

Takashi Inoue

Publications and source records attributed to Takashi Inoue.

105 records · Page 6Linked to original sources
PubMed2002

Behavior of epithelial root sheath during tooth root formation in porcine molars: TUNEL, TEM, and immunohistochemical studies.

The behavior of epithelial cells during tooth root formation in porcine molars was investigated using TUNEL, immunohistochemical and transmission electron microscopic methods. Cells of Hertwig's epithelial root sheath (HERS) expressed bcl-2, but were TUNEL-negative. Epithelial cells of HERS were tightly connected and surrounded by a continuous basement membrane. When dental papilla cells were attached to the inner HERS, they became positive for osteopontin (OPN). The inner basement membrane was intermittent immediately after those cells started to synthesize dentin matrix, and the intercellular spaces of the HERS became wider. Dental sac cells then migrated between the fragmented HERS and were directly connected to epithelial cells by desmosome-like structures. After the cementum was synthesized by these mesenchymal cells, epithelial cells aggregated to form cell clusters, which were again surrounded by a continuous basement membrane. These results suggest that fragmentation of the HERS is due to the invasion of dental sac cells, but is not related to cell death. Furthermore, the differentiation of dental papilla cells into odontoblasts occurred following their connection to the HERS through the basement membrane. Moreover, it is suggested that the differentiation of dental sac cells into cementoblasts occurred upon their direct connection to epithelial cells of the HERS.

Animals↗
PubMed2002

Selective reduction of diffusion anisotropy in white matter of Alzheimer disease brains measured by 3.0 Tesla magnetic resonance imaging.

Alzheimer disease (AD) is pathologically characterized by cortical atrophy. Changes in the white matter and their relation to the pathogenesis of AD remain to be studied. To quantitatively investigate the integrity and organization of white matter fiber tracts in patients with AD, we used diffusion tensor (DT) imaging to study the diffusion anisotropy of white matter regions. DT imaging was performed using a 3.0 Tesla magnetic resonance scanner in ten probable AD patients with no or only mild changes in the white matter in T2 weighted magnetic resonance imagings and ten group-matched controls. The values of fractional anisotropy were significantly lower in the temporal subcortical white matter, posterior part of the corpus callosum, and anterior and posterior cingulate bundles in patients with AD compared with controls. Possible relationships of these selective impairments in the white matter with pathological changes in the posterior cerebral cortices and hippocampus were discussed.

Aged↗
PubMed2002

Improvement of high fat-diet-induced insulin resistance in dipeptidyl peptidase IV-deficient Fischer rats.

F344/DuCrj rats are genetically deficient in dipeptidyl peptidase IV (DPPIV). This enzyme degrades glucagon-like peptide-1 (GLP-1), which induces glucose-dependent insulin secretion. Glucose tolerance of F344/DuCrj rats is improved as a result of enhanced insulin release induced by high levels of plasma GLP-1. In this study, we fed F344/DuCrj rats and DPPIV-positive F344/Jcl rats, aged five weeks, on a high-fat (HF) diet to examine the effect of DPPIV deficiency on food intake and insulin resistance. F344/Jcl rats gained significantly more body weight and consumed significantly more food than F344/DuCrj rats from Week 4 on either control or HF diet. Glucose excursion in the oral glucose tolerance test (OGTT) was improved in F344/DuCrj rats fed on the control or HF diet at all times examined, compared with F344/Jcl rats. Homeostasis model assessment (HOMA) insulin resistance values of F344/DuCrj and F344/Jcl rats fed on HF diet were higher than those of animals fed on control diet up to Week 6. However, HOMA insulin resistance values of F344/DuCrj rats fed on HF diet became significantly lower than those of F344/Jcl rats on HF diet during Weeks 8-10. The area under the insulin curve in the OGTT at Week 10 showed that the insulin resistance of HF-diet-fed F344/DuCrj rats was greatly ameliorated. Plasma active GLP-1 concentrations of F344/DuCrj rats in the fed state were significantly higher than those of F344/Jcl rats. These observations suggest that DPPIV deficiency results in improved glucose tolerance and ameliorated insulin resistance owing to enhanced insulin release and inhibition of food intake as a result of high active GLP-1 levels.

Animals↗
PubMed2002

Zic2 controls cerebellar development in cooperation with Zic1.

Mouse Zic genes encode zinc finger proteins and are expressed in the developing and mature CNS. Reduced expression of Zic2 in mice results in spina bifida and holoprosencephaly. However, the disruption of Zic1, a strong homolog of Zic2 that has an overlapping expression pattern, results in cerebellar malformation with no apparent abnormalities in the forebrain or in posterior neuropore closure. Here we revealed that Zic2 and Zic1 cooperatively control cerebellar development by regulating neuronal differentiation. Both Zic1 and Zic2 are expressed in the precursor cells of the granule neuron and the neurons in cerebellar nuclei. Mice carrying one mutated Zic1 allele together with one mutated Zic2 allele (Zic1(+/-)Zic2(+/kd)) showed a marked cerebellar folial abnormality similar to, but distinct from that found in mice homozygous for the Zic1 mutation (Zic1(-/-)). The Zic1(+/-)Zic2(+/kd) cerebellum is missing a lobule in the anterior vermis and has a truncation of the most posterior lobule. Expression of transverse zonal markers is shifted anteriorly in the developing cerebellum, indicating that the anterior part of the cerebellum is poorly developed. Abnormalities in the developing Zic1(+/-)Zic2(+/kd) cerebellum share the following features with those of the Zic1(-/-) cerebellum: a preceding reduction of cell proliferation in the anterior external germinal layer, a reduction in cyclin D1 expression, and enhanced expression of the mitosis inhibitors p27 and p16, and enhancement of Wnt7a expression. These results indicate that Zic1 and Zic2 may have very similar functions in the regulation of cerebellar development.

Animals↗
PubMed2002

Difference in penetration of horseradish peroxidase tracer as a foreign substance into the peri-implant or junctional epithelium of rat gingivae.

Horseradish peroxidase (HRP) tracer was applied to the gingival sulcus of implants or natural teeth at 5, 25, or 50 mg/ml to investigate the sealing capacities of the peri-implant epithelium (PIE) and junctional epithelium (JE); the extent of HRP penetration was observed under electron microscopy. A Ti-6Al-4V implant was inserted either immediately (immediate implantation) or 2 weeks (delayed implantation) after extraction of the maxillary left first molar of rats. The JE of the right molar was used as a control. Although the whole PIE of undecalcified sections appeared to be attached to the implant surface, electron microscopically, the internal basement lamina (IBL) and hemidesmosomes were deficient in the coronal-middle region of the PIE. There were extensive extracellular deposits of HRP in the intercellular spaces between PIE cells, and HRP was blocked to some extent by the lamina lucida and lamina densa of the external basal lamina and basal cell junction. HRP was detected in the connective tissue under the PIE, but was not found in the connective tissue under the JE. Intracellularly, HRP was found in the vesicles and granules of PIE cells and JE cells. These were fewer in number in PIE cells than in JE cells. There were no differences between the findings for immediate and delayed implantation. The results indicate that a deficiency in the IBL permitted penetration of HRP from the gingival sulcus into the connective tissue under the PIE, and suggest that the endocytotic capacity of PIE cells is inferior to that of JE cells.

Alloys↗
PubMed2002

Effect of Helicobacter pylori-induced cyclooxygenase-2 on gastric epithelial cell kinetics: implication for gastric carcinogenesis.

BACKGROUND: Cyclooxygenase (COX)-2 induced by Helicobacter pylori is thought to enhance gastric carcinogenesis by affecting the maintenance of epithelial homeostasis. MATERIALS AND METHODS: Gastric biopsies from 160 subjects, 97 with nonulcer dyspepsia (47 H. pylori negative, 50 H. pylori positive) and 63 with gastric cancer were examined immunohistochemically for COX-2 expression, cell proliferation and apoptotic indices. RESULTS: COX-2 expression in corpus was significantly higher in H. pylori positive than in negative non-ulcer dyspepsia (NUD) (p <.05). Regardless of site, gastric cancer subjects had higher COX-2 expression in both antrum and corpus compared with H. pylori negative and positive NUD (p <.005). Proliferation was higher in cancer and H. pylori positive than in negative NUD (p <.0001). Moreover, cancer had enhanced proliferation than H. pylori positive NUD in corpus greater (p =.0454) and antrum lesser (p =.0215) curvatures. Apoptosis was higher in H. pylori positive than in negative NUD (p <.05). However, both had a higher index than the cancer subjects (p <.0001). Apoptosis : proliferation ratio was higher in corpus of H. pylori negative than in positive NUD in greater (p =.0122) and lesser (p =.0009) curvatures. However, both had a higher A:P ratio than cancer cases (p =.0001). A negative correlation between COX-2 expression and A:P ratio was found in corpus greater (r = -.176, p =.0437) and lesser (r = -.188, p =.0312) curvatures. CONCLUSION: The expression of COX-2 is associated with disruption in gastric epithelial kinetics and hence may play a role in gastric carcinogenesis.

Adolescent↗
PubMed2002

Follicular/desmoplastic hybrid ameloblastoma with radiographic features of concomitant fibro-osseous and solitary cystic lesions.

We report a case of ameloblastoma radiographically suggestive of a complication of fibro-osseous and solitary cystic lesions. A 35-year-old woman was referred to our hospital for treatment, complaining of swelling in the left premolar region of the mandible. Radiological findings indicated a mixed radiopaque and radiolucent lesion in the region of the left mandibular canine and first premolar as well as a solitary cystic lesion in the mandibular second premolar region. Following biopsy, resection of mandible was performed under general anesthesia. Histopathologic examination identified follicular-type ameloblastoma with partial desmoplastic findings. Conventional radiography and computed tomography were not useful in indicating the relationship between the mixed and solitary cystic lesions. However, magnetic resonance imaging was instrumental in elucidating this relationship.

Adult↗
PubMed2002

Plasma nitrotyrosine concentration relates to prognosis in human septic shock.

Interrelation of plasma nitrotyrosine (NT) concentrations in patients of septic shock and their prognosis was examined. Blood samples were obtained from 12 patients during the first episode of septic shock at hospitalization, and their plasma NT concentrations were measured. Five patients died within five days after hospitalization, but seven patients recovered. Plasma NT concentrations (means +/- SE) of the non-survivors and survivors were 0.68 +/- 0.13 nmol/mL (n = 7), and 0.21 +/- 0.05 nmol/mL (n = 5), respectively, the former being significantly higher than the latter. The present results suggest that plasma concentration of NT relates to prognosis in human septic shock, although further studies with a larger patient population are necessary for confirmation of the suggestion.

Adult↗
PubMed2002

Cytokeratins expression of constituting cells in ameloblastoma.

The purposes of this study were to investigate the distribution of cytokeratins in the different tissue types of ameloblastoma and to discuss the histogenesis of this tumor. CK19 and CK8, which are markers for odontogenic epithelium, reacted positively to the constituting cells in all types of ameloblastoma. This suggests that all types of ameloblastoma derive from odontogenic epithelium. However, the desmoplastic type diminished the odontogenic characteristics because the basal cells are negative to CK19. Immunoreactions of five kinds of cytokeratin revealed similar results in plexiform, follicular, acanthomatous, and granular cell types. The plexiform type is probably the original type of ameloblastoma; the other types have the characteristics of squamous epithelium, and the follicular, acanthomatous, and granular cell types can develop due to the differentiation of cells of the plexiform type into squamous epithelium.

Ameloblastoma↗
PubMed2002

Lesions related to the formation of bone, cartilage or cementum arising in the oral area: a statistical study and review of the literature.

This report contains a statistical review of 559 cases of lesions forming hard tissues that were diagnosed by the departments of Clinical Pathophysiology and of Pathology at Tokyo Dental College from 1966 to 2001. Sixteen kinds of lesions which were related to the formation of bone, cartilage or cementum were analysed: osteoma, osteo-chondroma, chondroma, osteoid osteoma, osteoblastoma, ossifying fibroma, cemento-ossifying fibroma, cementifying fibroma, so-called cementoma, cementoblastoma, gigantiform cementoma, periapical cemental dysplasia, osteosarcoma, chondrosarcoma, fibro-osseous lesion, and fibrous dysplasia of bone. The most common lesion was osteoma (203 cases). There is a marked tendency for this condition to occur in females (201 males cases and 358 female cases). The patients' ages ranged from 3 to 84 years, and the mean was 40.1 years old. Lesions with hard tissue formation were observed most frequently in the third decade and in the mandibular molar region.

Adolescent↗
PubMed2002

Cell proliferation and expression of Cbfa-1 in a peripheral osteo-chondroma arising from the mandibular oral mucosa of an edentulous alveolar ridge.

This report describes the proliferation and the expression of Cbfa-1 in a rare case of peripheral osteo-chondroma arising from the mandibular oral mucosa of an edentulous alveolar ridge. Histologically, the lesion consisted of mesenchymal cells with either bone or cartilage tissue in the center. Almost all the tumor cells were reactive for PCNA, however, only the cells around the bone and cartilage tissues were reactive for Cbfa-1. These results suggest that both the bone and the cartilage tissues in this case were produced by mesenchymal cells that originated from the peripheral periosteum of the alveolar ridge. Furthermore, we have shown that immunohistochemical staining for PCNA and Cbfa-1 can be used to investigate lesions with bone or cartilage formation and to distinguish between those produced by osteogenic cells from those that are just reactive and produced by dystrophic calcification.

Aged↗
PubMed2002

Quantification of susceptibility artifacts produced on high-field magnetic resonance images by various biomaterials used for neurosurgical implants. Technical note.

Although various biomaterials such as ceramics or titanium alloy are widely used in neurosurgery, the susceptibility artifacts that appear around these materials cause problems when a magnetic resonance (MR) imager is used to assess lesions after surgery. The purpose of the present study was to quantify the susceptibility artifacts produced by various biomaterials used for neurosurgical implants. Using a 3-tesla MR imaging unit, we obtained MR images of various biomaterials, including six types of ceramics, a cobalt-based alloy (Elgiloy), pure titanium, a titanium alloy, and stainless steel. All implants shared a uniform size and shape. In each image, a linear region of interest was defined across the center of the biomaterial in the transverse direction, and the diameter of the susceptibility artifact was calculated. The ceramics produced a considerably smaller artifact diameter than those produced by other biomaterials. Among the types of ceramics, zirconia was found to produce the smallest artifact diameter. Among the remaining biomaterials, the diameters of the artifacts decreased in order from that associated with stainless steel to those associated with cobalt-based alloys, pure titanium, and titanium alloy. Little difference was observed between the artifact diameters associated with pure titanium and titanium alloy. Ceramics are the most suitable biomaterials for minimizing artifacts in high-field MR imaging.

Artifacts↗
PubMedDate not supplied

Response of Merkel cells in the palatal rugae to the continuous mechanical stimulation by palatal plate.

The aim of the present study was to investigate the responses of Merkel cells that are numerous in the palatine rugae, due to the continuous mechanical stimulation exerted by the palatal plate. Forty golden hamsters were used in this experiment. The palatal plate was made of adhesive resin and it was set on the palate of the animal. To exert a continuous pressure, a 0.8 mm elevation on the internal surface of the palatal plate was created at the middle portion of the fourth palatine ruga. Thereafter, the number of Merkel cells in the mucosa was calculated by immunohistochemical observation. Morphological changes of Merkel cells were examined by electron microscopy. There was significant difference among the control and any of the treated groups on the number of CK20 positive Merkel cells (p < 0.05) and that numbers were decreased at the sites where continuous mechanical stimulation was exerted. Degeneration of the cytoplasm mitochondria and nerve endings, and a decrease in both the number of neurosecretory granules and cytoplasmic processes were observed. Furthermore, the presence of nuclear chromatin aggregation and fragmentation was recognized. The continuous mechanical stimulation by the palatal plate affected the responses of Merkel cells and nerve endings, thus inducing a decrease in the number of Merkel cells. A portion of these changes was also associated with the expression of apoptosis.

Animals↗
PubMedDate not supplied

Qualitative versus quantitative assessment of cerebrovascular reactivity to acetazolamide using iodine-123-N-isopropyl-p-iodoamphetamine SPECT in patients with unilateral major cerebral artery occlusive disease.

BACKGROUND AND PURPOSE: Qualitative measurement of regional cerebrovascular reactivity (rCVR) to acetazolamide with single-photon emission CT (SPECT) has been widely used to determine the severity of hemodynamic impairment. We attempted to validate the accuracy of qualitative assessment by using SPECT to detect reduced rCVR compared with rCVR determined quantitatively in patients with unilateral major cerebral artery occlusion. METHODS: Regional cerebral blood flow was assessed with iodine-123-N-isopropyl-p-iodoamphetamine ((123)I-IMP) at rest and after acetazolamide activation in 133 patients with previously symptomatic, unilateral internal carotid or middle cerebral artery occlusion. Quantitative values were calculated by using the (123)I-IMP autoradiographic method and analyzed for each cerebral hemisphere as the percentage change in rCBF between resting and activation studies (%(Hem)). Qualitative rCVR was determined for the target hemisphere distal to the occlusion as the cerebral-interhemispheric asymmetry index (AI(Hem)) and as an index of flow difference between the target cerebral and ipsilateral cerebellar hemispheres (FI(Hem-Cbl)). Values 2 SDs below the mean in healthy volunteers were defined as decreased. RESULTS: Fair agreement was observed between %(Hem) and both AI(Hem) change (resting vs activation, kappa = 0.409) and FI(Hem-Cbl) change (resting vs activation, kappa = 0.440). When %(Hem) was assumed to represent the true determinant of assessing rCVR, AI(Hem) change and FI(Hem-Cbl) change demonstrated sensitivities of 68% and 78%; specificities, 72% and 76%; positive predictive values, 48% and 56%; false-positive incidences, 28% and 24%; and false-negative incidences, 32% and 22% for detecting patients with reduced rCVR, respectively. CONCLUSION: Subgroups of patients with hemodynamic impairment cannot be accurately defined by using rCVR qualitatively measured with SPECT.

Acetazolamide↗