Biomedical subjects

Y Abiko

Publications and source records attributed to Y Abiko.

At least 37 records · Page 2Linked to original sources

PubMed2001

Activities of plasminogen activator, plasmin and kallikrein in synovial fluid from patients with temporomandibular joint disorders.

To measure the activities of plasminogen activator (PA), plasmin and kallikrein, multiple synovial fluid samples were taken from 32 patients with internal derangement (ID) and osteoarthrosis (OA), and nine asymptomatic volunteers. The enzyme activity in synovial fluid from the temporomandibular joint (TMJ) was quantitated by a fluorogenic substrate assay using an enzyme substrate. In fluid samples from the patient group, PA was detected in 24 (31.5%), plasmin in 20 (26.3%) and kallikrein in 53 (96.4%), while none of these enzymes were found in the synovial fluid samples from the control group. There were positive correlations found among PA, plasmin and kallikrein. These results clearly demonstrated increased levels of PA, plasmin and kallikrein activities in the synovial fluid of patients with ID and OA, and suggest that these enzymes may be involved in the pathogenesis of synovitis, as well as the resorption of cartilage and bone in TMJ.

Adolescent↗

PubMed2001

Immunohistochemical localization of large chondroitin sulphate proteoglycan in porcine gingival epithelia.

In this study, we report the immunohistochemical localization of versican in healthy porcine gingival epithelia. The monoclonal antibody (mAb), 5D5, specifically recognizes core proteins of large chondroitin sulphate proteoglycans such as versican, neurocan and brevican, but not the core protein of aggrecan. Because neurocan and brevican appear to be specific to nervous tissue, the large chondroitin sulphate proteoglycans examined in this study is most likely versican. In the keratinized layer of the attached gingival epithelium, the basal and spinous cell surfaces showed intense staining for mAb 5D5. In the parakeratinized layer of the sulcus epithelium, the localization was restricted to the basal and lower spinous layers. In the junctional epithelium, intense staining was observed in one or two cell layers near the enamel surface. Immunoelectron microscopy revealed high-density depositions of 5D5 immunoreactivity on epithelial cell surfaces. At the enamel surface, 5D5 immunoreactivity was localized to the dental cuticle of the junctional epithelium but was not present in the internal basal lamina. These results suggest that versican, a large chondroitin sulphate proteoglycan, is involved in epithelial differentiation and downgrowth.

Animals↗

PubMed2001

IL-1beta increases uPA and uPA receptor expression in human gingival fibroblasts.

The binding of urokinase-type plasminogen activator (uPA) to its receptor (uPAR) in various cell types has been proposed as an important feature of many cellular processes requiring extracellular proteolysis, cell adhesion, motility, and invasion. uPAR attaches to the cell surface with a glycosylphophatidylinositol (GPI) anchor, and serves to localize and accelerate the proteolysis cascade. In this study, we examined both uPA and uPAR levels in human gingival fibroblasts treated with an inflammatory cytokine, interleukin-1beta (IL-1beta). PA activity in the cell lysate was increased by treatment with IL-1beta. Further, PA activity released by phosphatidylinositol-specific phospholipase C, which detaches the GPI anchor, was also increased by IL-1beta. The activity was inhibited by amiloride, a specific inhibitor of uPA. In addition, IL-1beta increased the protein and mRNA levels of both uPA and uPAR in gingival fibroblasts. These findings suggest that the enhancement of uPA and uPAR levels by IL-1beta may play an important role in the progression of periodontal diseases through pericellular proteolysis, and subsequent cellular behavior.

Cells, Cultured↗

PubMed2001

Purification and characterization of an oligo-isomaltosaccharide synthase from a Streptococcus sobrinus glucosyltransferase-I deficient mutant.

One glucosyltransferase (GTF) -I deficient mutant of Streptococcus sobrinus strain B13N was isolated through chemical mutagenesis with ethyl methanesulfonate, and characterized. This mutant, designated as B13N-Id, readily allowed us to purify a homogeneous oligo-isomaltosaccharide synthase (GTF-S) from its culture fluid. The purified GTF-S was only recognized with rabbit polyclonal antibody against recombinant GTF-S from an Ecsherichia coli MD124 clone expressing the B13N gtfS gene, and showed the almost same enzymatic properties as the recombinant enzyme. A double reciprocal plot of the B13N GTF-S for sucrose was biphasic, and the affinity for this substrate was high compared to that of GTF-S enzymes from other strains.

Chromatography, High Pressure Liquid↗

PubMed2001

Construction of a chimeric shuttle plasmid via a heterodimer system: secretion of an scFv protein from Bacillus brevis cells capable of inhibiting hemagglutination.

Passive immunization is an attractive therapy for preventing oral diseases including dental caries and periodontal disease. For this purpose, we attempted to produce a single chain variable fragment, scFv, which inhibited hemagglutination using the Bacillus brevis protein-producing system. To accomplish this, a novel strategy, a heterodimer system, was used for the construction of a chimeric shuttle plasmid. Initially, a set of new plasmids, kanamycin-resistant donor and erythromycin-resistant general cloning plasmids, were constructed. p15A ori was a common replication origin in these plasmids, while the pUB110 rep and minus origin (MO) were cloned into the donor plasmid. Next, the secretion domain of the B. subtilis alpha-amylase gene and the G2-4 gene, coding for the scFv protein, were cloned into the general cloning plasmid and fused by PCR. Both the donor plasmid and the general cloning plasmid containing the fused gene were digested with NotI and them ligated, a dimeric plasmid being constructed. The key restriction sites, AscI, are arranged such that the pUB110 rep-MO moiety was switched from the donor to the general cloning plasmid following AscI digestion. The chimeric shuttle plasmid was readily constructed by simple re-circularization and a B. brevis transformant producing the scFv protein in the culture fluid was isolated.

Amino Acid Sequence↗

PubMed2001

A sensitive method for detecting Porphyromonas gingivalis by polymerase chain reaction and its possible clinical application.

BACKGROUND: It is useful for the clinical diagnosis of periodontitis to monitor the colonization of periodontopathic bacteria in periodontal pockets. In this study, we attempted to establish and possibly identify the clinical application of a sensitive method to detect Porphyromonas gingivalis (P.g.), one of the putative periodontopathic bacteria related to chronic periodontitis. METHODS: Genomic DNA extracted from cultured P.g. 381 and clinically isolated subgingival plaque samples were used as a template of polymerase chain reaction (PCR). We designed primers to amplify the genomic DNA coding 40 kDa outer membrane protein (OMP), one of the unique proteins to all strains of P.g. The efficiency and specificity of amplification were evaluated by agarose gel electrophoresis and subsequent Southern hybridization with a digoxygenin-labeled oligonucleotide probe. RESULTS: Fewer than 100 P.g. bacterial cells in the specimen were reproducibly detected by PCR-hybridization assay. This PCR-hybridization assay was at least 100 times more sensitive than the conventional indirect immunofluorescence assay (IIF). Furthermore, the imaging analysis showed that there is a linear correlation between the strength of the signal and the cell number of P.g. from which the template DNA was extracted semiquantitatively. It is noteworthy that the PCR assay could also be applied to detect P.g. from clinical plaque samples and that it was approximately 100 times more sensitive than a conventional IIF assay. CONCLUSION: The PCR assay established in this study can be a powerful tool to detect P.g. in periodontal pockets and monitor the colonization and/or recolonization of P.g. at the very early phase.

Bacterial Outer Membrane Proteins↗

PubMed2001

Inhibition of hemolysis by antibody against the Porphyromonas gingivalis 130-kDa hemagglutinin domain.

Porphyromonas gingivalis is a gram-negative anaerobic bacterial species implicated as an important pathogen in the development of adult periodontitis. Hemagglutinin may mediate the adsorption and invasion of bacteria into host cells. Furthermore, the hemagglutinin plays a role in the agglutinate and lyse erythrocytes intake of heme which is an absolute requirement for this bacterial growth. We previously cloned the gene encoding the 130-kDa hemagglutinin protein domain (130-kDa HMGD) and identified the functional motifs of agglutination of erythrocytes. Bacterial cell attachment to erythrocytes is an important initial step in the expression of hemolytic activity. In this study, we highly purified recombinant r130-kDa HMGD and prepared the specific antiserum. Further, the effect of the antibody on the hemolytic activity of P. gingivalis cells was examined. The polyclonal antibody recognized 43,49-kDa major bands in P. gingivalis cells and r130-kDa HMGD, and significantly inhibited the hemagglutinating and hemolytic activities of P. gingivalis cells. The findings suggest that the antibody may be useful in the development of the passive immunization against periodontal diseases caused by P. gingivalis infection.

Animals↗

PubMed2001

Enhancement of plasminogen activator activity stimulated by LPS in gingival fibroblasts of individuals with Down syndrome.

Individuals with Down syndrome (DS) have a high prevalence of periodontal disease, which develops early and progressed rapidly and extensively, in comparison with healthy controls. The severe periodontal disease in individuals with DS has been considered to result from abnormal factors in their host responses. The mechanisms involved in the periodontal inflammatory processes in individuals with DS are not fully understood. Plasminogen activators (PA) are serine proteases that are well known for their part in the initiation of the fibrinolytic cascade leading to the generation of plasmin in periodontal homeostasis, including fibrinolysis and connective tissue remodeling. The PA-plasmin system affects the progression of periodontal disease. In the present study, we examined the effects of the levels of PA activity stimulated with lipopolysaccharide (LPS) in the gingival fibroblasts from donors with DS (DGF). The levels of PA activity without LPS were low in the DGFs, the same as that in the gingival fibroblasts from donors of healthy controls (NDGF). In contrast, the levels of PA activity with LPS in DGFs were significantly higher than that in the NDGFs. These results suggested that PA plays an important role in inducing extensive and rapid inflammation in the periodontal disease in individuals with DS.

Adolescent↗

PubMed2001

[Secretion and dynamics of herpes simplex virus in tear and saliva of patients with Bell's palsy].

Herpes simplex virus (HSV) involvement has been clarified as the cause of Bell's palsy by molecular biological techniques. To clarify the direct relationship between virus reactivation and paralysis development, both detection of the virus genome by DNA-diagnostic and quantitative analysis of its time-course change are needed. Using polimerase chain reaction (PCR) method and microplate-hybridization combined, we detected the virus genome in small amount of specimens from patients with Bell's palsy, quantified its number of copies, and examined time-course changes. We attempted to type of HSV in positive specimens. Subjects were 16 patients with Bell's palsy positive for serum anti-HSV IgG antibody (enzyme immunoassay) who visited the outpatient clinic of Department of Otorhinolaryngology, Itabashi Hospital, Nihon University School of Medicine, within 14 days after onset without having any treatment. Tears and saliva from the parotid gland and the submaxillary gland were separately collected from the affected side and healthy side twice or more. A total of 244 specimens was subjected to DNA extraction, PCR, and microplate-hybridization, and HSV DNA was detected in 38 specimens (11.8%) from 5 patients (31%). From sampling time, the highest detection (28.5%) was obtained within 2 weeks after onset. Detection at 3 weeks and later (2.8%) was significantly lower (p < 0.05). DNA was also found on the healthy side, but in comparison between sides, detection on the healthy side (18.9%) was significantly lower than that on the affected side (83.8%) (p < 0.01). In quantitative determination of the virus genome, the amount (number of copies) was large on the affected side and largest early after onset regardless of the clinical course. Positive specimens underwent HSV-typing, and HSV-1 was found in all of them, suggesting that HSV-1 reactivation is a cause of Bell's palsy.

Adolescent↗

PubMed2001

[Facial paralysis evaluations using the Yanagihara method, the House-Brackmann method, and self-evaluation by patients].

The Yanagihara method and the House-Brackmann (H-B) method are widely used in Japan to evaluate facial paralysis. The present study focuses on the relationship between the evaluation of facial paralysis using these methods and self-evaluation by patients. One-hundred and thirty-one patients with facial paralysis were included in the study, consisting of 68 males and 63 females between the ages of 17 and 84 years (mean age: 41 +/- 18 years). In addition to the Yanagihara and H-B methods, two methods of self-evaluation were used by the patients. In the first self-evaluation method, the patient was asked to rate the degree of paralysis as a grade of one to six. In the second method, the patient was asked to rate the severity of the paralysis on a scale of 0-100. The paralysis scores and grades determined using the Yanagihara and H-B methods were correlated with the self-evaluations. However, the strength of the correlation varied among the patients, indicating that the evaluation of subjective symptoms differed among individuals. Even patients who were evaluated as either "completely paralyzed" or "cured" according to the Yanagihara and H-B methods did not always rate their subjective symptoms as being consistent with these scores. In particular, 20 to 30% of patients who were evaluated as "cured" complained of minor dyskinesia.

Adolescent↗

PubMed2000

Mechanical stress enhances expression and production of plasminogen activator in aging human periodontal ligament cells.

Plasminogen activator (PA) converts plasminogen to plasmin, and plasmin activates the kinin cascade and latent extracellular matrix metalloproteases. The periodontal ligament serves to anchor the tooth to the alveolus and functions as a cushion between these hard tissues to migrate occlusal force during mastication. We reported previously that repeated mechanical tension force (MTF) as an experimental model of a traumatic occlusion, increased PA activity in human periodontal ligament derived fibroblast (hPLF) cells. In this study, the influence of in vitro cellular aging on MTF-stimulated PA activity in hPLF cells was studied. Aged hPLF cells produced a significantly higher PA activity when compared with those of young hPLF cells in response to MTF in a time- and magnitude-dependent manner. tPA mRNA levels in aged cells were higher than those in young cells, whereas PAI-1 mRNA remained unchanged and uPA mRNA was not detected. Because MTF-stimulated PA activity from hPLF cells was increased by in vitro cellular aging, aging of the periodontal ligament may affect the severity of the inflammation and the degradation of the extracellular matrix of periodontal ligament tissue by producing a large amount of PA in response to excessive force such as a traumatic occlusion.

Bite Force↗

PubMed2000

Pulsed electromagnetic fields promote bone formation around dental implants inserted into the femur of rabbits.

The present study examined the effect of applying a pulsed electromagnetic field (PEMF) on bone formation around a rough-surfaced dental implant. A dental implant was inserted into the femur of Japanese white rabbits bilaterally. A PEMF with a pulse width of 25 microseconds and a pulse frequency of 100 Hz was applied. PEMF stimulation was applied for 4 h or 8 h per day, at a magnetic intensity of 0.2 mT, 0.3 mT or 0.8 mT. The animals were sacrificed 1, 2 or 4 weeks after implantation. After staining the resin sections with 2% basic fuchsin and 0.1% methylene blue, newly formed bone around the implant on tissue sections was evaluated by computer image analysis. The bone contact ratios of the PEMF-treated femurs were significantly larger than those of the control groups. Both the bone contact ratio and bone area ratio of the 0.2 mT- and 0.3 mT-treated femurs were significantly larger than the respective value of the 0.8 mT-treated femurs (P < 0.001). No significant difference in bone contact ratio or bone area ratio was observed whether PEMF was applied for 4 h/day or 8 h/day. Although a significantly greater amount of bone had formed around the implant of the 2-week treated femurs than the 1-week treated femurs, no significant difference was observed between the 2-week and 4-week treated femurs. These results suggest that PEMF stimulation may be useful for promoting bone formation around rough-surfaced dental implants. It is important to select the proper magnetic intensity, duration per day, and length of treatment.

Alloys↗

PubMed2000

Inhibitory effect of low-level laser irradiation on LPS-stimulated prostaglandin E2 production and cyclooxygenase-2 in human gingival fibroblasts.

It has been reported that lipopolysaccharide (LPS) from periodontal pathogens can penetrate gingival tissues and stimulate the production of prostaglandin E2 (PGE2), which is known as a potent stimulator of inflammation and bone resorption. Although biostimulatory effects of low-level laser irradiation such as anti-inflammatory results have been reported, the physiological mechanism is not yet clarified. The purpose of the present study was to determine the effect of laser irradiation on PGE2 production and cyclooxygenase (COX)-1 and COX-2 gene expression in LPS-challenged human gingival fibroblast (hGF) cells in vitro. hGF cells were prepared from healthy gingival tissues and challenged with LPS, and Ga-Al-As diode laser was irradiated to the hGF cells. The amount of PGE2 released in the culture medium was measured by radioimmunoassay, and mRNA levels were analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR). Irradiation with Ga-Al-As diode low-level laser significantly inhibited PGE2 production in a dose-dependent manner, which led to a reduction of COX-2 mRNA levels. In conclusion, low-level laser irradiation inhibited PGE2 by LPS in hGF cells through a reduction of COX-2 mRNA level. The findings suggest that low-level laser irradiation may be of therapeutic benefit against the aggravation of gingivitis and periodontitis by bacterial infection.

Analysis of Variance↗

PubMed2000

Stimulation of prostaglandin E2 and interleukin-1beta production from old rat periodontal ligament cells subjected to mechanical stress.

Although the severity of periodontal disease is known to be affected by the age of the host, the pathological role of aging in periodontal disease, especially that attributable to trauma from occlusion, has not been well characterized. Prostaglandin (PG)E2 and interleukin (IL)-1beta are key mediators involved in periodontal diseases, potent stimulators of bone resorption, and are produced by human periodontal ligament (PDL) cells in response to mechanical stress. To investigate age-related changes in the biosynthetic capacity of PGE2 and IL-1beta in PDL cells, we examined the effects of in vivo aging with mechanical tension on PGE2 and IL-1beta expression by rat PDL cells. PDL cells obtained from the incisors of 6-week (young) and 60-week (old) rats were cultured on flexible-bottomed culture plates. The cells were deformed by causing a 9% or 18% increase in surface area at 6 cycles per minute for 1 to 5 days. We found an approximately twofold increase in PGE2 and IL-1beta production by old PDL cells subjected to mechanical tension compared with that by young cells, although the constitutive levels were similar in both. The expression of cyclooxygenase (COX)-2 and IL-1beta mRNA (messenger ribonucleic acid) was enhanced by mechanical tension as determined by use of reverse transcription-polymerase chain reaction (RT-PCR), whereas COX-1 and IL-1beta-converting enzyme mRNA remained unchanged. It is possible that the large amount of PGE2 and IL-1beta produced by PDL cells from an aged host in response to mechanical force may be positively related to the acceleration of alveolar bone resorption.

Aging↗

PubMed2000

Production, characterization, and application of monoclonal antibodies which distinguish four glucosyltransferases from Streptococcus sobrinus.

A 1,3-alpha-glucan synthase (GTF-I), a highly branched 1, 6-alpha-glucan synthase (GTF-U) and a 1,6-alpha-glucan synthase (GTF-T) were purified to near homogeneity from the culture fluid of Streptococcus sobrinus strain B13N (serotype d) and characterized. In addition, a crude preparation of a recombinant oligo-isomaltosaccharide synthase (rGTF-S) was prepared from a cell-free extract of Escherichia coli MD124 transformant. Using four homogeneous GTF preparations including previously purified rGTF-S as antigens for immunization, 11 murine hybridomas producing a monoclonal antibody (MAb) were established through the fusion of myeloma cells (P3X63-Ag8-U1) and spleen cells of immunized BALB/c mice. When the immunoreactivities of the resultant MAbs were tested, all five MAbs raised against GTF-I, all three MAbs raised against GTF-T, and two of three MAbs raised against GTF-U reacted specifically with the homologous enzyme alone, while one MAb (B86) raised against GTF-U cross-reacted strongly with all GTFs. Although no MAb monospecific for rGTF-S was obtained, precise recognition of GTF-S was possible using the nonspecific B86 antibody together with the MAbs monospecific for the three glucan synthases. Thus, a set of four typical MAbs (B17, B76, B19 and B86) were successfully used for the identification of gene products expressed in 24 previously constructed E. coli phage clones, and the findings suggested that six phage clones might express a gtfU gene encoding GTF-U which has not been hitherto isolated.

Animals↗

PubMed2000

Passive immunization against dental caries and periodontal disease: development of recombinant and human monoclonal antibodies.

Indigenous micro-organisms in the oral cavity can cause two major diseases, dental caries and periodontal diseases. There is neither agreement nor consensus as to the actual mechanisms of pathogenesis of the specific virulence factors of these micro-organisms. The complexity of the bacterial community in dental plaque has made it difficult for the single bacterial agent of dental caries to be determined. However, there is considerable evidence that Streptococcus mutans is implicated as the primary causative organism of dental caries, and the cell-surface protein antigen (SA I/II) as well as glucosyltransferases (GTFs) produced by S. mutans appear to be major colonization factors. Various forms of periodontal diseases are closely associated with specific subgingival bacteria. Porphyromonas gingivalis has been implicated as an important etiological agent of adult periodontitis. Adherence of bacteria to host tissues is a prerequisite for colonization and one of the important steps in the disease process. Bacterial coaggregation factors and hemagglutinins likely play major roles in colonization in the subgingival area. Emerging evidence suggests that inhibition of these virulence factors may protect the host against caries and periodontal disease. Active and passive immunization approaches have been developed for immunotherapy of these diseases. Recent advances in mucosal immunology and the introduction of novel strategies for inducing mucosal immune responses now raise the possibility that effective and safe vaccines can be constructed. In this regard, some successful results have been reported in animal experimental models. Nevertheless, since the public at large might be skeptical about the seriousness of oral diseases, immunotherapy must be carried out with absolute safety. For this goal to be achieved, the development of safe antibodies for passive immunization is significant and important. In this review, salient advances in passive immunization against caries and periodontal diseases are summarized, and the biotechnological approaches for developing recombinant and human-type antibodies are introduced. Furthermore, our own attempts to construct single-chain variable fragments (ScFv) and human-type antibodies capable of neutralizing virulence factors are discussed.

Adhesins, Bacterial↗

PubMed2000

Ranolazine attenuates palmitoyl-L-carnitine-induced mechanical and metabolic derangement in the isolated, perfused rat heart.

The effect of ranolazine, a novel anti-ischaemic drug that stimulates the activity of pyruvate dehydrogenase, on palmitoyl-L-carnitine-induced mechanical dysfunction and metabolic derangement in isolated perfused rat hearts has been studied and compared with the effect of dichloroacetate, an activator of pyruvate dehydrogenase. Rat hearts paced electrically were perfused aerobically at constant flow by the Langendorff technique. Palmitoyl-L-carnitine (4 microM) increased left ventricular end-diastolic pressure and reduced left ventricular developed pressure (i.e. induced mechanical dysfunction); it also reduced tissue levels of adenosine triphosphate and increased tissue levels of adenosine monophosphate (i.e. induced metabolic derangement). These functional and metabolic alterations induced by palmitoyl-L-carnitine were attenuated by ranolazine (5, 10, and 20 microM) in a concentration-dependent manner. In contrast, dichloroacetate (1 and 10 mM) did not attenuate palmitoyl-L-carnitine-induced mechanical and metabolic derangement. In the normal (palmitoyl-L-carnitine-untreated) heart, however, ranolazine did not modify mechanical function and energy metabolism. These results suggest that ranolazine attenuates palmitoyl-L-carnitine-induced mechanical and metabolic derangement in the rat heart, and that the beneficial action of ranolazine is not because of the energy-sparing effect or activation of pyruvate dehydrogenase.

Acetanilides↗

PubMed2000

In vitro apatite induction by phosphophoryn immobilized on modified collagen fibrils.

Noncollagenous phosphoproteins that interact with type I collagen are thought to nucleate the mineral phase to collagen network of mineralized tissues. Previously, we found that phosphophoryn cross-linked to type I collagen was an effective nucleator of apatite. Here, we investigated the potential role of collagen telopeptide structure on this nucleation. We used pepsin and sodium borohydride (NaBH4) to modify the telopeptide region and reducible cross-links in the collagen fibrils and determined the effect on mineral induction by phosphophoryn cross-linked to it. The amount of phosphophoryn cross-linked to NaBH4-reduced collagen fibrils was higher than that to intact (unmodified) collagen fibrils. However, the amount of phosphophoryn cross-linked to collagen that lacked the telopeptides (atelocollagen) was 25% of that cross-linked to intact collagen fibrils. Each preparation was incubated at 37 degrees C in metastable calcium phosphate solutions that did not spontaneously precipitate. Apatite was induced by phosphophoryn cross-linked to intact collagen fibrils at 15.0 h whereas phosphophoryn cross-linked to reduced collagen fibrils induced apatite formation after 10.9 h. Enough phosphophoryn was cross-linked to atelocollagen to induce mineral formation, but it did not. The failure of the phosphophoryn-atelocollagen complex to nucleate mineral might have been caused by a cross-linking pattern in the helical portion of the collagen molecule that did not promote the growth of the calcium-phosphate clusters into nuclei. The present study indicates that the telopeptide domains of type I collagen play a role in the interaction with phosphophoryn, which is critical for the nucleation process.

Animals↗