PubMed Health⌕ Search

Biomedical subjects

O Takeichi

Publications and source records attributed to O Takeichi.

17 recordsLinked to original sources
PubMed2006

Co-production of vascular endothelial cadherin and inducible nitric oxide synthase by endothelial cells in periapical granuloma.

AIM: To clarify the mechanisms of inflammatory cell migration in human periapical granulomas by examining vascular endothelial (VE) cadherin and inducible nitric oxide synthase (iNOS)-producing cells. METHODOLOGY: Periapical tissues were obtained from patients during endodontic surgery and were divided into two portions. After fixing the tissues with acetone or 4% paraformaldehyde in phosphate-buffered saline, 5-microm-thick paraffin or cryostat sections were prepared, respectively. The paraffin sections of the inflamed tissues were evaluated histologically with haematoxylin-eosin stains. Cryostat sections of the tissue, diagnosed as periapical granulomas, were then examined by either immunohistochemistry using anti-human VE-cadherin or iNOS antibodies (Abs) for the characterization of infiltrating cells. In addition, co-localization of VE-cadherin and iNOS production was also analysed by two-colour immunofluorescence image analysis. RESULTS: Endothelial cells were strongly stained with iNOS Abs. Macrophages, lymphocytes, polymorphonuclear leucocytes and fibroblasts also exhibited iNOS production. These iNOS-positive cells accumulated around the blood vessels. On the other hand, VE-cadherin production was exhibited in only endothelial cells. Two-colour immunofluorescence image analysis using VE-cadherin and iNOS Abs demonstrated that iNOS-producing endothelial cells also showed VE-cadherin production. CONCLUSIONS: Vascular endothelial-cadherin produced by endothelial cells could be regulated by iNOS-producing cells in periapical granulomas and might play a pivotal role in vascular permeability.

Adult↗
PubMed2006

Mitogen-activated protein kinase/extracellular signal-regulated protein kinase activation of cultured human dental pulp cells by low-power gallium-aluminium-arsenic laser irradiation.

AIM: To examine whether low-power laser irradiation (LPLI) promotes cellular proliferation of human dental pulp-derived fibroblast-like cells (dental pulp cells). METHODOLOGY: Dental pulp cells were obtained by primary culture of human dental pulp tissues from extracted third molar teeth. The phosphorylation of the mitogen-activated protein kinase (MAPK) family after LPLI of these cells was investigated by Western blotting. By using a specific MAPK/ERK kinase (MEK) inhibitor (PD098059), the specific effect of LPLI on the MAPK pathway was also investigated by Western blotting as described above. The incorporation of [3H]thymidine into the cells after LPLI was determined, and statistical analysis was performed by Wilcoxon signed-ranks test. RESULTS: Extracellular signal-regulated protein kinase (ERK) 1/2 was phosphorylated between 5 and 30 min after LPLI. Moreover, PD098059 inhibited LPLI-mediated ERK1/2 activation. LPLI did not affect p38 MAPK or c-Jun N-terminal kinase (JNK) phosphorylation. But LPLI did not stimulate [3H]thymidine incorporation into these cells. CONCLUSIONS: These results indicated that LPLI activated MAPK/ERK, a signal for proliferation, differentiation and survival, but did not activate the stress signals p38 MAPK and JNK in human dental pulp cells.

Dental Pulp↗
PubMed2006

Effect of mineral trioxide aggregate on proliferation of cultured human dental pulp cells.

AIM: To investigate the effect of mineral trioxide aggregate (MTA) on the proliferation of human dental pulp (HDP) cells ex-vivo. METHODOLOGY: Human dental pulp cells were cultured with MTA or calcium hydroxide-containing cement (Dycal) using culture plate inserts. Control cells were cultured with culture plate inserts only. Cell proliferation was measured for up to 14 days using a Cell Counting kit, and the concentration of calcium ions released from the tested materials was assessed using a Calcium E-test kit. To confirm that the effect of MTA was attributable to released calcium ions, cell proliferation was measured in the presence of exogenous calcium chloride as a source of calcium ions while in the absence of MTA. RESULTS: Mineral trioxide aggregate significantly stimulated cell proliferation after 12 days, whereas Dycal had no such effect. The number of calcium ions released from MTA was significantly higher than that released from Dycal. Following the addition of calcium chloride, cell proliferation increased in a dose-dependent manner after 12 days. Moreover, cell proliferation showed a similar pattern whether a given concentration of calcium ions was produced by calcium chloride or by release from MTA. CONCLUSIONS: In this ex-vivo study, the elution components such as calcium ions from MTA had higher proliferation ability of HDP cells than control and Dycal.

Adult↗
PubMed2005

Behaviour of bone marrow osteoblast-like cells on mineral trioxide aggregate: morphology and expression of type I collagen and bone-related protein mRNAs.

AIM: To investigate the in vitro behaviour of rat bone marrow cells (RBM) on mineral trioxide aggregate (MTA) (ProRoot, MTA Root Canal Repair Material; Dentsply Tulsa, Tulsa, OK, USA) compared with intermediate restorative materials (IRM) (Dentsply Caulk, Milford, DE, USA). METHODOLOGY: RBM were obtained from rat femur and were primary cultured and then subcultured. Cells were then seeded on three dishes of each material, and cultured for 3 days, after which they were evaluated morphologically using scanning (SEM) and transmission (TEM) electron microscopy. Furthermore, the calcium released from hydrated material, the cell proliferation ratio and alkaline phosphatase (ALP) activity were analysed, and the expression of type I collagen and bone-related protein mRNAs were evaluated. The data were averaged and analysed via one-way analysis of variance (anova) and were then compared by the Scheffe's test. RESULTS: SEM showed that RBM attached to MTA and had a flattened appearance without nuclear protrusions and microspikes. TEM showed that the cells attached in the same manner as the control group, but gaps larger than 2 microm were frequently seen. The calcium released from hydrated MTA was about 130 ppm after 3 days of immersion in saline. The ALP activity was similar to the control group. Cell proliferation and expression of type I collagen mRNA was significantly lower, while the expression of osteopontin mRNA was significantly higher than the control group at the third day of culture. In IRM groups, a few rounded cells were observed on the material but no living cells were seen. CONCLUSIONS: MTA is a material of low toxicity which does not inhibit cell growth, but does suppress the differentiation of osteoblast-like cells.

Alkaline Phosphatase↗
PubMed2002

Non-surgical root canal treatment of dens invaginatus type 2 in a maxillary lateral incisor.

AIM: To describe the clinical management of an unusual dens invaginatus type 2. SUMMARY: A case of dens invaginatus in a maxillary lateral incisor with a periapical lesion is reported. The patient presented with pain and localized swelling. Despite the complex anatomy and diagnosis of dens invaginatus, non-surgical root canal treatment was performed successfully. Key learning points Dens invaginatus may be presented in many forms, and the aetiology of this phenomenon is not fully understood. Due to abnormal anatomical configuration, dens invaginatus presents technical difficulties in its clinical management. Non-surgical root canal treatment can be performed successfully.

Calcium Hydroxide↗
PubMed2002

Non-surgical root canal treatment of dens invaginatus type 2 in a maxillary lateral incisor.

AIM: To describe the clinical management of an unusual dens invaginatus type 2. SUMMARY: A case of dens invaginatus in a maxillary lateral incisor with a periapical lesion is reported. The patient presented with pain and localized swelling. Despite the complex anatomy and diagnosis of dens invaginatus, non-surgical root canal treatment was performed successfully. KEY LEARNING POINTS: * Dens invaginatus may be presented in many forms, and the aetiology of this phenomenon is not fully understood. * Due to abnormal anatomical configuration, dens invaginatus presents technical difficulties in its clinical management. * Non-surgical root canal treatment can be performed successfully.

Calcium Hydroxide↗
PubMed2000

Cytokine profiles of T-lymphocytes from gingival tissues with pathological pocketing.

Periodontal disease is an infection in which destruction occurs at sites remote from the infection, resulting in pathological pocketing. Intervening between the infection and the destruction is a dense mononuclear inflammatory infiltrate. It has been suggested that this infiltrate might have characteristics and the destructive potential of Th1-type T lymphocytes. To ascertain the nature of the infiltrates we investigated the expression of mRNA for IL-2, IL-5, and IFN-gamma by gingival mononuclear cells (GMC) from healthy (n = 8) or adult periodontitis (AP) patients (n = 25) by using cytokine-specific reverse-transcription/polymerase-chain-reaction (RT-PCR). GMC, as obtained from patients' tissues, expressed IL-2, IFN-gamma, or IL-5 mRNA. Significantly higher proportions of GMC from AP patients expressed IL-2 and IFN-gamma mRNA than did those from healthy subjects. IFN-gamma was the most consistent cytokine message detected. In other experiments, gingival T-lymphocytes (n = 12) and CD4+ and CD8+ gingival T-lymphocytes (n = 16) were isolated from gingival tissues removed surgically from AP patients. AP gingival T-lymphocytes expressed mRNA for IL-2, IFN-gamma, or IL-6 prior to stimulation. After stimulation with Con A, the cells significantly up-regulated IL-5 and IL-6 message expression. Both CD4+ and CD8+ gingival T-lymphocytes expressed IFN-gamma, IL-5, and some IL-2. This cumulative cytokine profile observed in these experiments is consistent with the predominance of Th1-type cells in pathological tissues and with Th2-type cells, which can also be present, being up-regulated under appropriate stimulation. Importantly, CD4+ and CD8+ lymphocytes were shown to express T1- and T2-type cytokine message, emphasizing the potential for CD8+ T-lymphocytes to participate in periodontal disease pathology.

Adolescent↗
PubMed1999

Inducible nitric oxide synthase activity by interferon-gamma-producing cells in human radicular cysts.

AIM: In this study, the interaction of interferon-gamma-(IFN-gamma) and inducible nitric oxide synthase (iNOS)-producing cells in human radicular cysts were investigated. METHODOLOGY: Inflamed periapical tissues were obtained from patients at the time of endodontic surgical treatments and were cut into two pieces. After fixing with acetone or 4% paraformaldehyde in phosphate-buffered saline, 5-m-thick paraffin and cryostat sections were prepared. The paraffin sections of the inflamed tissues were evaluated histologically with haematoxylineosin stains. The specimens diagnosed as radicular cysts were then examined by immunostaining. Immunohistochemistry for iNOS and fluoresence microscopy for IFN-gamma using the cryostat sections were performed with a mixture of affinity purified human iNOS antiserum and human IFN-gamma monoclonal antibodies. RESULTS: The results revealed that iNOS-gamma producing cells localized adjacent to IFN-gamma-producing cells. In addition, some of iNOS-producing cells exhibited immunoreactive IFN-gamma. On the other hand, epithelial cells showed significant levels of iNOS production, but not IFN-gamma. CONCLUSIONS: The data would suggest the possibility that iNOS production could be precisely controlled by autocrine or paracrine effects of IFN-gamma producing cells in radicular cysts and might play a pivotal role in periapical lesions. These findings are consistent with a hypothesis suggesting that NO inhibitors could be used through the root canals as a pharmacological treatment for periapical lesions.

Adult↗
PubMed1998

Production of human-inducible nitric oxide synthase in radicular cysts.

To examine if nitric oxide (NO) is produced in radicular cysts, NO synthase (NOS) production was analyzed. Periapical tissues were removed from patients at the time of endodontic surgery. Frozen tissue sections were histologically evaluated with hematoxylin-eosin staining. Production of human-inducible NOS (iNOS) in apical cysts was then immunohistochemically examined. Immunoreactive human iNOS was widely distributed in epithelial cells, endothelial cells, fibroblasts, macrophages, or polymorphonuclear leukocytes. Remarkably, iNOS-positive cells were significantly present around blood vessels, and cells residing apart from the blood vessels showed weak or no iNOS production, suggesting that only cells around blood vessels could be stimulated for iNOS synthesis. These data demonstrated the possibility that several, but not all, cells could be stimulated to synthesize iNOS in inflamed tissues. In the presence of iNOS, NO can be produced spontaneously in periapical lesions and may play a crucial role in the regulation of chronic infection.

Enzyme Induction↗
PubMed1998

Cytokine regulation on the synthesis of nitric oxide in vivo by chronically infected human polymorphonuclear leucocytes.

To determine if nitric oxide (NO) is produced by chronically infected human polymorphonuclear leucocytes (PMNs) in vivo, inflamed exudates (periapical exudates: PE) collected from periapical periodontitis patients were examined. Cell-free supernatants and cells were separated by centrifugation. Significant levels of nitrite concentrations were observed in the supernatants. The production of inducible NO synthase (iNOS) in highly purified PMNs derived from PEs was then immunocytochemically determined using rabbit anti-human iNOS antiserum. In vitro, human peripheral blood PMNs (PB-PMNs) isolated from patients were cultured with a combination of Esherichia coli-lipopolysaccharide (LPS), recombinant human interferon-gamma (rhIFN-gamma) and/or interleukin-1 beta (rhIL-1 beta). The stimulated PB-PMNs showed steady-state levels of nitrite. The stimulation of LPS, rhIFN-gamma and rhIL-1 beta showed more NO induction than that of LPS with either IFN-gamma or IL-1 beta, suggesting the synergistic effects of cytokines. Cryostat sections of surgically removed periapical tissues were also immunohistochemically examined for iNOS, IFN-gamma and IL-1 beta. Two-colour immunohistochemistry revealed the interaction of iNOS-producing PMNs and IFN-gamma- or IL-1 beta-producing mononuclear cells. On the basis of these data, we concluded that with the stimulation of inflammatory cytokines derived from mononuclear cells, PMNs can spontaneously produce NO at the site of chronic infection. The present studies are consistent with a hypothesis suggesting that PMNs could be regulated and delicately balanced to produce NO by mononuclear cell-derived cytokines in vivo. NO-producing cells may play a pivotal role in chronic inflammation.

Adult↗
PubMed1996

Expression of inflammatory cytokine genes in vivo by human alveolar bone-derived polymorphonuclear leukocytes isolated from chronically inflamed sites of bone resorption.

Alveolar bone-derived polymorphonuclear leukocytes (PMNs) were characterized for their ability to produce inflammatory cytokines such as interleukin-1 alpha (IL-1 alpha), IL-1 beta, tumor necrosis factor alpha (TNF alpha), and IL-6 in vivo. Periapical exudates (PE) were collected from periapical lesions with chronic periapical periodontitis through root canals. Cells and noncellular supernatants were then isolated by centrifugation. The concentration of cytokines present in the noncellular supernatants were determined by ELISA. High concentrations of IL-1 alpha, IL-1 beta, and IL-6 were detected in PE, however, TNF alpha was not. PE contains predominantly PMNs ( > 95% of residing cells) with a few percent of lymphocytes and/or macrophages. These alveolar bone-derived PMNs were purified by the Ficoll-Hypaque gradient method and were analyzed for cytokine mRNA expression using the cytokine-specific reverse-transcription polymerase chain reaction. Highly purified PMNs ( > 99.5%) isolated from PE expressed significant levels of mRNA for IL-alpha, IL-1 beta, and TNF alpha. IL-6 mRNA was not detected, although a high concentration of IL-6 was detected in supernatants of PE by ELISA. The IL-6 secretion in PE could be derived from macrophages, T lymphocytes, osteoblasts, or fibroblasts around periapical lesions. These data strongly suggest that human PMNs derived from alveolar bone can spontaneously produce IL-1 alpha, IL-1 beta, and TNF alpha at sites of inflammation, and probably initiate inflammation and regulate augmentation of bone resorption in vivo.

Adolescent↗
PubMed1994

Human polymorphonuclear leukocytes derived from chronically inflamed tissue express inflammatory cytokines in vivo.

In this study, we sought to determine if human polymorphonuclear leukocytes (PMNs) derived from chronically inflamed tissues can produce inflammatory cytokines in vivo. Human gingival crevicular fluid (GCF) with adult periodontitis was collected, and PMNs in GCF were examined after purified by Ficoll-Hypaque gradient method. Cytokines from peripheral blood (PB) cells stimulated with concanavalin A, LPS, or zymosan were also characterized, since GCF contains predominantly PMNs (> 95%) with a small number of lymphocytes or macrophages. Production of interleukin-1 alpha (IL-1 alpha), IL-1 beta, tumor necrosis factor-alpha (TNF alpha), and IL-6 in GCF or culture supernatants of peripheral blood cells was determined by ELISA. Significant levels of IL-1 alpha and IL-1 beta secretion were found in GCF. PB cells in culture showed prominent cytokine production from monocytes/macrophages, followed by lymphocytes. Human peripheral blood PMNs (PB-PMNs) also produced low levels of IL-1 alpha and IL-1 beta, but not TNF alpha and IL-6. These cells were also examined for cytokine mRNA expression using the reverse transcription-polymerase chain reaction analysis. Highly purified PMNs (> 99.5%) from GCF expressed mRNA for IL-1 alpha, IL-1 beta and TNF alpha, but not for IL-6. PB-PMNs in culture also showed mRNA expression for IL-1 alpha, IL-1 beta, and TNF alpha in a time- and dose-dependent manner, especially after stimulation with zymosan. Therefore, we concluded that human PMNs from inflamed tissues can produce IL-1 alpha, IL-1 beta, and TNF alpha in vivo, but not IL-6.

Adult↗
PubMed1976

Histochemical studies of monoamine oxidase in experimental myocardial infarctions.

Sequential histochemical studies were conducted to determine the level of monoamine oxidase (MAO) activity in the infarcted tissue of the experimental myocardial infarction in dog. MAO activity was not found in the normal heart muscle, but the activities were present in the wall of the coronary artery histochemically. Fibroblasts and collagen fibers began to take the place of the destroyed heart muscles in the infarcted area from 10 days after the coronary occlusion in dogs, and MAO activities were noted sporadically in the fibroblasts and the interstices of the collagen fibers in the infarcted area. MAO activities increased histochemically in the fibroblasts and the fiber interstices in the infarcted area 10 days or more after the coronary occlusion. These findings suggested the presence of the active collagen metabolism outside the myocardial cells in the infarcted area in the recovery stage of the experimental myocardial infarction. It was also suggested that the interstices of the collagen fibers in the myocardial wall constituted the lymphatic ducts outside the blood vessels and that the MAO activity in serum determined by the method in which tryptamine hydrochloride was used as substrate might indicate the grade of fibrosis of the myocardial tissue in the infarcted areas.

Animals↗