Development of Rat Caries-Induced Pulpitis Model for Vital Pulp Therapy

Rodent animal models for vital pulp therapy are commonly used in dental research because their tooth anatomy and cellular processes are similar to the anatomy and processes in humans. However, most studies have been conducted using uninfected sound teeth, which makes it difficult to adequately assess the inflammatory shift after vital pulp therapy. In the present study, we aimed to establish a caries-induced pulpitis model based on the conventional rat caries model and then evaluate inflammatory changes during the wound-healing process after pulp capping in a model of reversible pulpitis induced by carious infection. To establish the caries-induced pulpitis model, the pulpal inflammatory status was investigated at different stages of caries progression by immunostaining targeted to specific inflammatory biomarkers. Immunohistochemical staining revealed that both Toll-like receptor 2 and proliferating cell nuclear antigen were expressed in moderate and severe caries-stimulated pulp, indicating that an immune reaction occurred at both stages of caries progression. M2 macrophages were predominant in moderate caries-stimulated pulp, whereas M1 macrophages were predominant in the severe caries-stimulated pulp. Pulp capping in teeth with moderate caries (i.e., teeth with reversible pulpitis) led to complete tertiary dentin formation within 28 d after treatment. Impaired wound healing was observed in teeth with severe caries (i.e., teeth with irreversible pulpitis). During the wound-healing process in reversible pulpitis after pulp capping, M2 macrophages were predominant at all time points; their proliferative capacity was upregulated in the early stage of wound healing compared with healthy pulp. In conclusion, we successfully established a caries-induced pulpitis model for studies of vital pulp therapy. M2 macrophages have an important role in the early stages of the wound-healing process in reversible pulpitis.

Environmental impact of removal of a large-scale sluice gate on Nakaumi Lagoon and adjacent coastal waters, southwest Japan: Evidence from long-term foraminiferal monitoring

A large-scale sluice gate, which was built in southwest Japan as a national project to reclaim and desalinate lagoon water in 1974, was removed between 2005 and 2009. To examine the impact of this removal on both Nakaumi Lagoon and the nearby coastal waters, we analyzed the foraminiferal assemblages of a coastal sediment core and of samples obtained during 10 years of lagoon monitoring (2001-2010). Detailed 210Pb(ex) dating of the sediment core revealed an increased sediment accumulation rate in the coastal waters, implying that discharge of fine-grained materials, including organic matter, was facilitated by removal of the sluice gate. The observed increase in agglutinated foraminifera and decrease in calcareous species was related to the sediment accumulation rate, and these changes occurred close to 2005, when sluice-gate removal began. In Nakaumi Lagoon, the sporadic presence of the coastal species Quinqueloculina seminula within the 6-m water column and the decline in the lagoon-adapted Ammonia "beccarii" have occurred since 2005. The removal of the sluice gate, plus the sea-level rise, allowed greater seawater inflow and stabilized the monthly deep-water salinity fluctuations in Nakaumi Lagoon.

Preliminary investigation of 222Rn in the Yakumo Wind-hole, an algific talus deposits, from Izumo, southwest Honshu, Japan

The Yakumo Wind-hole in southwest Japan formed by landslip, and it is known as a cold air blowhole. This wind-hole consists of two parts, which have complementary relationships in regard to the flow of air, namely, topographically upper and lower holes that can be characterized as a warm wind-hole (WWH) and cold wind-hole (CWH), respectively. We carried out a preliminary investigation of radon behavior in the Yakumo Wind-hole. The data showed remarkable seasonal change from high ²²²Rn concentrations reaching to 7.6 ± 0.1 kBq/m³ in the warm season (mid-May to October) to low ²²²Rn concentrations in the cold season (December to early May) at the CWH. The threshold in the regional atmospheric temperature was estimated as 16.2 °C for the beginning and 17.1 °C for the ending periods of air blow with higher ²²²Rn concentrations. These seasonal changes in ²²²Rn were not only associated with the dynamic convection caused by temperature differences in and out of the talus, but were also related to the relative humidity of air that is blown out. High ²²²Rn concentrations were formed in the high humidity environment, and the humidity may possibly be associated with melting ice. According to the known information on ²²²Rn behavior in relation to humidity, a radon trap in the growing ice in spring and in the melted water in summer are suggested. This study revealed that ²²²Rn measurements are a useful tool to understand the air dynamics in the talus.

Genetic Mapping of the Absence of Third Molars in EL Mice to Chromosome 3

We noted the absence of all 4 third molars (M3) in Epilepsy-Like disorder (EL) mice, an animal model for the study of epilepsy. This study was conducted to identify the major candidate chromosome and to detect the region that included the candidate gene causing the absence of M3 in EL mice. Linkage analysis was performed on genetic crosses of EL mice and MSM ( Mus musculus molossinus) strain mice, which had a normal complement of teeth. Genome-wide screening by individual genotyping of F2intercross mice identified mouse chromosome 3 as one of the candidate chromosomes. Based on high linkage scores in detailed genotyping of F2intercross and N2backcross mice, the candidate locus for the absence of M3 in EL mice was mapped on the middle of chromosome 3.

A specific Streptococcus mutans strain aggravates non-alcoholic fatty liver disease

OBJECTIVE

Streptococcus mutans, a major dental caries pathogen, has shown to be associated with the aggravation of cerebral hemorrhage and inflammatory bowel diseases. In this study, we evaluated the effects ofS. mutans on the development of non-alcoholic steatohepatitis (NASH) in a mouse model.

MATERIALS AND METHODS

Streptococcus mutans oral strain MT8148 (serotype c) and a blood isolate TW871 (k) were used. C57BL/6J mice (6 weeks old)were fed a high-fat diet for 4 weeks; the test strains or phosphate-buffered saline was then intravenously administered. Mice were euthanized after 8 or 12 weeks. Whole body, extirpated liver, and visceral fat weights were determined, and histopathological evaluations of the liver specimens were performed.

RESULTS

Mice infected with TW871 showed significantly greater body and liver weights than those administered MT8148 or phosphate-buffered saline. Histopathological analyses revealed prominent infiltration of inflammatory cells and adipocellular deposition in livers extirpated 8 weeks after an infection with TW871; fibrosis was also observed in livers extirpated after 12 weeks.

CONCLUSION

These results suggest that a specific strain of S. mutans could induce NASH.

Control of the wetting properties of ^{4}He crystals in superfluid

To investigate whether it is possible to control the wetting of ^{4}He crystals on a wall in superfluid, the contact angles of ^{4}He crystals were measured on rough and smooth walls at very low temperatures. A rough wall was prepared in a simple manner in which a commercially available coating agent for car mirrors, which makes the glass surface superhydrophobic, was used to coat a glass plate. The contact angles of ^{4}He crystals were increased by approximately 10^{∘} on the rough wall coated with the agent. Therefore, the increase in the repellency of ^{4}He crystals in superfluid was demonstrated to be possible on a very rough surface. The enhancement of the contact angles and a scanning electron microscopy image of the coated surface both suggest that a Cassie-Baxter state of ^{4}He crystals was realized on the surface; the crystals did not have full contact with the wall, but entrapped superfluid was present beneath the crystals in the hollow parts of the rough wall.

Relationship between Cnm-positive Streptococcus mutans and cerebral microbleeds in humans

OBJECTIVE

Cerebral hemorrhage has been shown to occur in animals experimentally infected with Streptococcus mutans carrying the collagen-binding Cnm gene. However, the relationship between cerebral microbleeds and oral hygiene, with a focus on Cnm gene-positive S. mutans infection, remains unclear.

MATERIAL AND METHODS

One hundred and thirty-nine subjects participated. The presence or absence of Cnm-positive S. mutans and its collagen-binding activity were investigated using saliva samples, and relationship with cerebral microbleeds detected on MRI investigated, including clinical information and oral parameters.

RESULTS

Fifty-one subjects were identified as Cnm-positive S. mutans carriers (36.7%), with cerebral microbleeds being detected in 43 (30.9%). A significantly larger number of subjects carried Cnm-positive S. mutans in the cerebral microbleeds (+) group. S. mutans with Cnm collagen-binding ability was detected in 39 (28.1%) of all subjects, and the adjusted odds ratio for cerebral microbleeds in the Cnm-positive group was 14.4. Regarding the presence of cerebral microbleeds, no significant differences were noted in the number of remaining teeth, dental caries, or in classic arteriosclerosis risk factors.

CONCLUSIONS

The occurrence of cerebral microbleeds was higher in subjects carrying Cnm-positive S. mutans, indicating that the presence of Cnm-positive S. mutans increases cerebral microbleeds, and is an independent risk for the development of cerebrovascular disorders.

Spin-dependent acoustic response in the nonunitary A1 and A2 phases of superfluid 3He under high magnetic fields

The transverse acoustic impedance of superfluid ^{3}He was measured in the A1 and A2 phases up to 13 T to investigate the surface states in nonunitary superfluids. The temperature dependence of the impedance was much larger in the A1 phase than in the A2 phase. This nonsymmetric behavior indicates that momentum exchange with walls for spin-down surface states is quite different from that for spin-up surface states. The spin-dependent response might be a reflection of an essential feature of the nonunitary states where gap amplitudes depend on spin states. Weak-coupling theories ignore any spin-dependent processes and do not account for the nonsymmetric behavior.

A new late Eocene Bicornucythere species (Ostracoda, Crustacea) from Myanmar, and its significance for the evolutionary history of the genus

The ostracode genus Bicornucythere (Ostracoda, Crustacea) is abundant in modern-day eutrophic marine bays, and is widely distributed in estuaries and inner bays throughout East Asia, including in China, Korea, Japan, and the Russian Far East. The evolutionary history of Bicornucythere is poorly understood. Here, we report on a new species of Bicornucythere (Bicornucythere concentrica sp. nov.) from the upper Eocene Yaw Formation in the Central Myanmar Basin. The oldest previously known Bicornucythere taxon, Bicornucythere secedens, was reported from lower Miocene strata in India, although a molecular phylogeny suggests that the genus first appeared in the Late Cretaceous. Bicornucythere concentrica sp. nov. is at least 10.9 million years older than the earliest known B. secedens. The new species occurs with Ammonia subgranulosa, a benthic foraminifer, an association that is representative of brackish water conditions in modern Asian bays. Our findings indicate that extant genera have inhabited Asian bays since the late Eocene. The paleobiogeography of Bicornucythere indicates that the taxon was dispersed onto Indian coasts during the collision between the Indian and Eurasian plates.

Anthropogenic impacts on meiobenthic Ostracoda (Crustacea) in the moderately polluted Kasado Bay, Seto Inland Sea, Japan, over the past 70 years

Two sediment cores were obtained from Kasado Bay, a moderate-polluted enclosed bay in Japan, to examine anthropogenic impacts on Ostracoda over the past ca. 70 years. We analyzed ostracode abundance and diversity, grain size, and CHN, and used (210)Pb and (137)Cs as the dating method. The present study showed that cross-plot comparisons of ostracode abundance and each environmental factor, based on sediment core data, could be used to identify ostracode species as indicators for anthropogenic influences. Ostracode abundance reflected mainly the changes that had occurred in total organic carbon content in sediments related to eutrophication, but heavy metal concentration did not directly influence several ostracode abundance in the bay. Environmental deterioration because of eutrophication started in the 1960s. The regulations regarding the chemical oxygen demand in waters introduced in the 1980s probably influence ostracode abundance for certain species in this period. Currently, Kasado Bay is not experiencing severe degradation.

Aggravation of inflammatory bowel diseases by oral streptococci

OBJECTIVES

Streptococcus mutans can aggravate colitis in mice. We evaluated the virulence of colitis using type strains as well as blood isolates of several oral streptococcal species.

MATERIALS AND METHODS

We investigated the susceptibility of blood isolates of several oral streptococci to phagocytosis, adhesion to and invasion of hepatic cells and interferon-γ secretion. A mouse model of dextran sodium sulphate-induced colitis was used to evaluate bacterial aggravation of colitis. In addition, interferon-γ antibody was administered to mice with prominent aggravation of colitis.

RESULTS

In vitro analyses showed that Streptococcus sanguinis ATCC 10556 was a possible virulent strain among type strains of several oral streptococci, and that analysis of blood isolates of S. sanguinis TW289 revealed a potential virulent strain. Intravenous administration of ATCC 10556 and TW289 caused prominent aggravation of dextran sodium sulphate-induced colitis, and histopathological examinations showed that interferon-γ secretion due to infection of hepatic cells caused colitis aggravation. Administration of interferon-γ antibody suppressed TW289-induced colitis.

CONCLUSION

These results suggest that some virulent oral streptococcal strains are associated with the aggravation of colitis induced by enhanced secretion of interferon-γ when they invade the bloodstream.

Opening of the closed water area and consequent changes of ²²⁸Ra/²²⁶Ra activity ratios in coastal lagoon Nakaumi, southwest Japan

In Lake Nakaumi, the second largest coastal lagoon in Japan, artificially closed (Honjyo) area, which was left untouched for 28 years, was partly opened in May, 2009. (228)Ra/(226)Ra ratio of waters in Honjyo area and Lake Nakaumi showed a well-tuned seasonal variation exhibiting high value in summer. After the opening event, however, the (228)Ra/(226)Ra ratios in the Honjyo water showed an unclear seasonal variation in both surface and deep water. This opening event caused the change of active movement of lake and marine water.

The effect on the bones of condensed phosphate when used as food additives: Its Importance in Relation to Preventive Medicine

Based on the fact that chemical products such as binding agents are produced by mixing three kinds of phosphates with different ratios, we mixed metaphosphate, polyphosphate and pyrophosphate. Each was made to Na-phosphate, K-phosphate, and Ca-phosphate and each was mixed with commercial feeds so that the content of P would be approximately 0.1, 0.15, 0.3, 0.4, 0.6 and 1.0%. The prepared pellets were given to ICR, CF # 1 and AKR strains of mice at 29 days of age for 680 days and observations were made through this experimental period at different stages. The observations were also carried out on the mice administered with the experimental feeds for 1.5 months from 9 to 10.5 months of age. The observations were compared with those of the control group at all times. As a result, plasma 1 α, 25 (OH)(2) D(3) and P levels were always significantly higher in the phosphate administered groups relative to the control. Urine P and Fe increased while urine Ca decreased in the phosphate-treated groups.The effect of phosphates on the bones was studied taking soft X-ray pictures of hind legs and applying microdensitometry to them. Through these observations we recognized thinning of the cortex of bones, reduction of marrow trabecules and development of osteophyte. Histological observations disclosed that changes in knee joint tissues were apparent; that is, a decrease in or an irregular loss of the number of cells in superficial, intermediate, and radial strata of the joint cartilage, proliferation of subchondral bone, and the development of osteophytes were noted. As for muscles, diameters of musclar fibers became smaller; in particular, type II fibers showed greater shrinkage. Regarding kidneys, swelling and atrophy of glomerular capillaries, proliferation of mesangial cells, nephroselerosis, swelling, thinning, and loss of tubular epithelium, interstitial tissue inflammation, development of cylindruria, and deposition of calcium were observed. All these changes seem to be a particularly advanced aspect of the changes which are more pronounced with increasing dose and age.These changes were found even in the group administered with the feed containing 0.1% phosphorus, and, these changes were dependent on the concentration level of P. It was observed that administration to older subjects for a short term (1.5 months) produced effects stronger than those to younger subjects administered for a long term (10.5 months).The effects of condensed Ca-phosphate on bones were similar to those of condensed Na- and K-phosphates, and, hence, it was supposed that these effects were caused by phosphate radicals.

Potential involvement of collagen-binding proteins of Streptococcus mutans in infective endocarditis

OBJECTIVE

Streptococcus mutans, a major pathogen of dental caries, is considered to be one of the causative agents of infective endocarditis (IE). Two types of cell surface collagen-binding proteins, Cnm and Cbm, have been identified in the organism. The aim of the present study was to analyze these proteins as possible etiologic factors for IE.

MATERIALS AND METHODS

The binding activities of S. mutans strains to collagen types I, III, and IV were analyzed relative to the presence of Cnm and Cbm, as were their adhesion and invasion properties with human umbilical vein endothelial cells (HUVEC). In addition, distributions of the genes encoding Cnm and Cbm in S. mutans-positive heart valve specimens extirpated from IE and non-IE patients were analyzed by PCR.

RESULTS

Most of the Cbm-positive strains showed higher levels of binding to type I collagen as well as higher rates of adhesion and invasion with HUVEC as compared to the Cnm-positive strains. Furthermore, the gene encoding Cbm was detected significantly more frequently in heart valve specimens from IE patients than from non-IE patients.

CONCLUSIONS

These results suggest that the collagen-binding protein Cbm of S. mutans may be one of the potential important factor associated with the pathogenesis of IE.

Surface Andreev bound states of superfluid 3He and Majorana fermions

Superfluid (3)He is an intensively investigated and well characterized p-wave superfluid. In the bulk Balian-Werthamer state, which is commonly called the (3)He B phase, the superfluid gap is opened isotropically but near a flat boundary such as a wall of a container it can harbor interesting quasi-particle states inside the gap. These states are called surface Andreev bound states, and have not been experimentally explored in detail. Transverse acoustic impedance measurement has revealed their existence and provided spectroscopic details of the dispersion of the bound states. Recent theoretical arguments claim that the surface Andreev bound states of the superfluid (3)He B phase can be recognized as the edge states of the topological superfluid and be regarded as a Majorana fermion, a fancy particle which has not been confirmed in elementary particle physics. In this review, we present up-to-date knowledge on the surface Andreev bound states of the (3)He B phase revealed by acoustic spectroscopy and the possible realization of a Majorana fermion, along with related studies on this topic.

Distribution of periodontopathic bacterial species in dogs and their owners

OBJECTIVE

Presently, a large number of individuals consider their companion animals as family members and have close contact with them in daily life. The purpose of the present study was to analyze the distribution of periodontopathic bacterial species in oral specimens taken from dogs and their owners.

DESIGN

Dental plaque specimens were collected from 66 dogs and 81 members of 64 families who came to an animal clinic or dog training school in Okayama, Japan, in 2011. Bacterial DNA was extracted from each specimen and PCR analyses using primers specific for 11 periodontopathic species, Porphyromonas gingivalis, Porphyromonas gulae, Treponema denticola, Tannerella forsythia, Capnocytophaga ochracea, Capnocytophaga sputigena, Prevotella intermedia, Prevotella nigrescens, Aggregatibacter actinomycetemcomitans, Campylobacter rectus, and Eikenella corrodens were performed.

RESULTS

P. gulae (71.2%), T. forsythia (77.3%), and C. rectus (66.7%) were frequently found in the dogs, whereas the detection rates of those species in humans were less frequent at 16.0%, 30.9%, and 21.0%, respectively. P. gulae was identified in 13 human subjects and each of their dogs was also positive for the species. Furthermore, E. corrodens and T. denticola in specimens obtained from dogs were correlated with their presence in specimens from owners who had close contact with them.

CONCLUSIONS

These results suggest that several periodontopathic species could be transmitted between humans and their companion dogs, though the distribution of periodontopathic species in both is generally different.

Strong suppression of the Kosterlitz-Thouless transition in a 4He film under high pressure

We have found that the surface specularity for 3He quasiparticle scattering is closely related to the superfluidity and the Kosterlitz-Thouless (KT) transition of 4He film adsorbed on the surface. The specularity is determined by measurements of the transverse acoustic impedance of bulk liquid 3He. The unique point of our system is that we can control the correlation among 4He atoms in the film by changing the pressure of the bulk 3He. The observed KT transition temperature is significantly suppressed by increasing the pressure, which suggests a strong correlation effect on KT transition.

The influences of various anthropogenic sources of deterioration on meiobenthos (Ostracoda) over the last 100 years in Suo-Nada in the Seto Inland Sea, southwest Japan

This study focuses on the relationships of water and sediment quality with meiobenthos (Ostracoda) over the past 100 years, using a sediment core obtained from Suo-Nada in the Seto Inland Sea, Japan. We compared high-resolution ostracode results with geochemical and sedimentological data obtained from the study core as well as with rich environmental monitoring data that are available. R-mode cluster analysis revealed two bioassociations (BC, KA). Until the 1960 s, assemblages continued to show high diversity. They changed in approximately 1970, when excessive nutrients and organic matter began to be supplied, and most species decreased in number. All species of bioassociation BC were dominant again by the mid-1990 s; however, those of bioassociation KA containing infaunal species did not increase and have been absent or rare since the 1970s because organic pollution of sediments has continued to date. This study provided robust baseline for ostracode-based long-term environmental monitoring in East Asia.

Characterization of aortic aneurysms in cardiovascular disease patients harboring Porphyromonas gingivalis

OBJECTIVE

Porphyromonas gingivalis was recently shown to cause intimal hyperplasia in a mouse model by a novel cholesterol-independent mechanism, suggesting to be a pathogen-specific feature of cardiovascular diseases. The aim of this study was to characterize the clinical and histopathological features of aortic aneurysms in cardiovascular disease patients harboring oral P. gingivalis.

SUBJECT AND METHODS

Aortic aneurysm specimens were collected from 76 Japanese patients who underwent surgery, of whom dental plaque specimens were also collected from 31 patients. Bacterial DNA was extracted from each specimen to detect P. gingivalis by polymerase chain reaction. Histopathological analyses of the aortic aneurysm specimens, including immunohistochemical staining for embryonic myosin heavy chain isoform (SMemb) and S100 calcium-binding protein A9 (S100A9), were also performed.

RESULTS

The number of aneurysms occurring in the distal aorta was significantly higher in subjects positive for P. gingivalis in dental plaque compared with those who were negative. The expressions of S100A9 and SMemb were also significantly greater in the subjects positive for P. gingivalis in dental plaque. On the other hand, there were no significant differences in adipocellular accumulation between the groups.

CONCLUSIONS

These results suggest that aortic aneurysms in patients harboring oral P. gingivalis have greater expression of S100A9 and proliferative smooth muscle cells, which was different from the present patients without oral P. gingivalis.

Molecular characterization of Streptococcus mutans strains containing the cnm gene encoding a collagen-binding adhesin

OBJECTIVE

Streptococcus mutans, known to be a major pathogen of dental caries, is also considered to cause infective endocarditis. Its 120-kDa Cnm protein binds to type I collagen, which may be a potential virulence factor. In this study, we characterized S. mutans clinical strains focusing on the cnm gene encoding Cnm.

DESIGN

A total of 528 S. mutans strains isolated from Japanese, Finnish, and Thai subjects were investigated. Using molecular techniques, the distribution frequency of cnm-positive strains and location of the inserted cnm were analyzed. Furthermore, isogenic mutant strains were constructed by inactivation of the cnm gene, then their biological properties of collagen-binding and glucan-binding were evaluated. Southern hybridization of the genes encoding glucan-binding proteins was also performed.

RESULTS

The distribution frequency of cnm-positive strains from Thai subjects was 12%, similar to that previously reported for Japanese and Finnish subjects. Furthermore, the location of insertion of cnm was the same in all cnm-positive clinical isolates. As for the cnm-inactivated mutant strains constructed from 28 clinical isolates, their collagen-binding activity was negligible. In addition, glucan-binding activity in the cnm-positive clinical isolates was significantly reduced and corresponded to a lack of gbpA encoding glucan-binding protein A.

CONCLUSIONS

Our results indicate that strains with cnm genes, the most crucial factor for the collagen-binding property of S. mutans, are detectable at similar frequencies over several different geographic locations. In addition, the common properties of these strains are a high level of collagen-binding activity and tendency for a low level of glucan-binding activity.

Contribution of cell surface protein antigen c of Streptococcus mutans to platelet aggregation

INTRODUCTION

Streptococcus mutans is considered to be one of the pathogens that cause infective endocarditis. The purpose of the present study was to examine the properties of S. mutans with regard to platelet aggregation by focusing on its high molecular protein antigen c (PAc).

METHODS

The platelet aggregation properties of six clinical strains and one isogenic mutant strain of S. mutans were analysed using an aggregometer and confocal microscopy, as well as with an inhibition assay of platelet aggregation using anti-PAc serum.

RESULTS

S. mutans strains with PAc expression induced platelet aggregation, while a PAc-deficient mutant and two clinical isolates with no PAc expression did not. When platelets were pretreated with higher amounts of anti-PAc serum, the platelet aggregation rate was reduced in a dose-dependent manner, indicating that PAc binds directly to platelets.

CONCLUSION

S. mutans PAc is involved in human platelet aggregation and may be one of the virulence factors in the pathogenesis of infective endocarditis.

Molecular analysis of aortic intimal hyperplasia caused by Porphyromonas gingivalis infection in mice with endothelial damage

BACKGROUND AND OBJECTIVE

Porphyromonas gingivalis infection is thought to be a significant etiological factor in the development of cardiovascular diseases. However, scant definitive evidence has been presented concerning the pathological molecular mechanisms of these disorders. In the present study, we performed a molecular analysis of the developmental mechanisms of aortic intimal hyperplasia induced by P. gingivalis.

MATERIAL AND METHODS

The effects of P. gingivalis-induced bacteremia on intimal hyperplasia were evaluated using a mouse model of aortic hyperplasia created by photochemical-induced endothelial cell injury. Alterations of gene expression profiles in injured blood vessels of the mice were extensively analyzed using DNA microarray assays to identify the key molecules involved in P. gingivalis-induced hyperplasia. In addition, human aneurismal specimens from patients with or without P. gingivalis infection were analyzed histochemically.

RESULTS

Intravenous administration of P. gingivalis dramatically induced intimal hyperplasia in the mouse model. Concomitantly, S100 calcium-binding protein A9 (S100A9) and embryonic isoform of myosin heavy chain (SMemb), a proliferative phenotypic marker of smooth muscle cells, were significantly overexpressed on the surfaces of smooth muscle cells present in the injured blood vessels. Similarly, increased expressions of S100A9 and SMemb proteins were observed in aneurismal specimens obtained from P. gingivalis-infected patients.

CONCLUSION

We found that bacteremia induced by P. gingivalis leads to intimal hyperplasia associated with overexpressions of S100A9 and SMemb. Our results strongly suggest that oral-hematogenous spreading of P. gingivalis is a causative event in the development of aortic hyperplasia in periodontitis patients.

New anomaly in the transverse acoustic impedance of superfluid 3He-B with a wall coated by several layers of 4He

We measured the transverse acoustic impedance of superfluid 3He-B with a wall coated by several layers of 4He. The coating is known to enhance the specularity in quasiparticle scattering by the wall. We found a new anomaly, a bump and a peak, in the temperature dependence of the transverse acoustic impedance. This agrees with a theoretical calculation using a partially specular wall boundary condition. The new anomaly is shown to arise from a change in the surface density of states by coating and the scattering of thermally occupied surface bound states to other states. The change is towards the density of states of Majorana cone in the specular limit.

Signalling pathway mediated by CXCR7, an alternative chemokine receptor for stromal-cell derived factor-1α, in AtT20 mouse adrenocorticotrophic hormone-secreting pituitary adenoma cells

Stromal cell-derived factor (SDF)-1 and its receptor, CXCR4, have been identified in both neurones and glia of many brain areas. Previous studies have mainly focused on the role of SDF-1 and CXCR4 in modulating the hypothalamic-pituitary axis and their possible involvement in the development of pituitary adenomas. An alternative SDF-1 receptor, CXCR7, has recently been identified, but it has not been studied in the context of pituitary adenomas. The present study aimed to investigate the distribution and function of CXCR7 in pituitary adenomas. The expression of CXCR7, normalised to β-actin, was assessed by tissue microarray analysis of 62 adenomas, including 23 growth hormone (GH)-producing adenomas, 22 nonfunctioning adenomas, seven prolactin (PRL)-producing adenomas, six adrenocorticotrophic hormone-producing adenomas and four thyroid-stimulating hormone-producing adenomas. In vitro functional studies used RNA interference (RNAi) and cDNA microarray analysis to evaluate the CXCR7 signalling pathway in AtT-20 mouse pituitary adenoma cells treated with recombinant mouse SDF-1α and transfected with RNAi against Cxcr7 or control RNAi. In tissue microarray analysis, prominent expression of CXCR7 was observed in GH-producing adenomas and PRL-producing adenomas, and in macroadenomas (P < 0.05). Intracellular signalling via CXCR7 up-regulated Bub1, Cdc29 and Ccnb1, and down-regulated Asns, Gpt, Pycr1, Cars and Dars. The present study demonstrates that the SDF-1α ⁄ CXCR7 signalling pathway regulates genes involved in cell cycle control, amino acid metabolism and ligase activity, which comprise targets that are distinct from those of CXCR4.

Molecular analyses of bacterial DNA in extirpated heart valves from patients with infective endocarditis

BACKGROUND/AIMS

Infective endocarditis (IE) is caused by a microbial infection of the endothelial surface of the heart. Although blood culture examinations are commonly used to determine the associated bacterial species, molecular techniques, which enable rapid identification of targeted bacterial species, have recently been applied in clinical cases.

METHODS

Nine heart valve specimens from IE patients (six subacute cases and three acute cases) were extirpated and collected, then bacterial DNA was extracted. Bacterial species in the specimens were determined by two different molecular methods and the results were compared with those from a conventional blood culture technique. In addition, a comparison between the two molecular methods was carried out using known numbers of six streptococcal species.

RESULTS

The conventional blood culture method revealed the bacterial species in eight cases, while one was found to be negative. Multiple species were identified in most of the cases by both molecular methods; however, those specified by one method were not always consistent with those specified by the other. Furthermore, the species determined by the blood culture technique were not always identified by the molecular methods. We also found that the two molecular methods used in the present study were extremely sensitive to detect from 1 to 100 cells of individual oral streptococcal species.

CONCLUSION

Our results suggest that species specified by molecular methods may have disseminated incidentally into the bloodstream, so interpretation of such results should be carefully undertaken in clinical situations.

Detection of oral bacteria in cardiovascular specimens

BACKGROUND/AIMS

Oral bacteria, including cariogenic and periodontal pathogens, are thought to be etiological factors in the development of cardiovascular diseases. To define this relationship, we analyzed the distribution of oral bacterial species in cardiovascular specimens.

METHOD

Following acceptance into the study, 203 consecutive patients were analyzed, from whom 82 aortic valve specimens, 35 mitral valve specimens, and 86 aortic aneurysmal wall specimens, of which 16 contained aneurysmal thrombus tissues, were obtained. In addition, a total of 58 dental plaque specimens were collected from the same group of patients who underwent heart valve replacement or removal of aortic aneurysms. Bacterial DNA was extracted from both cardiovascular tissues and dental plaque in those cases and then species-specific polymerase chain reaction assays were used to analyze the occurrences of six oral streptococcal and six periodontal bacterial species.

RESULTS

Streptococcus mutans was the most frequently detected species in the cardiovascular specimens, followed by Aggregatibacter actinomycetemcomitans. As for dental plaque specimens from patients who underwent cardiovascular operations, most of the tested periodontitis-related species as well as oral streptococci were detected at high frequencies. Furthermore, the positive rate of S. mutans in cardiovascular specimens from patients whose dental plaque specimens were also positive for S. mutans was 78%, which was significantly higher than any other tested species when the same analysis was performed.

CONCLUSION

Our results suggest that specific oral bacterial species, such as S. mutans and A. actinomycetemcomitans, are related to bacteremia and may be etiologic factors for the development of cardiovascular diseases.

Protein antigen in serotype k Streptococcus mutans clinical isolates

Streptococcus mutans, a major pathogen of dental caries and infective endocarditis, is classified into serotypes c, e, f, and k, with serotype k strains recently reported to be frequently detected in persons with infective endocarditis. Thus, we hypothesized that common properties associated with infective endocarditis are present in those strains. Fifty-six oral S. mutans strains, including 11 serotype k strains, were analyzed. Western blotting analysis revealed expression of the 3 types of glucosyltransferases in all strains, while expression of the approximately 190-kDa cell-surface protein (PA) was absent in 12 strains, among which the prevalence of serotype k (7/12) was significantly high. Furthermore, cellular hydrophobicity and phagocytosis susceptibility were lower in the group of serotype k strains. These results indicate that the absence of PA expression, low cellular hydrophobicity, and phagocytosis susceptibility are common bacterial properties associated with serotype k strains, which may be associated with virulence for infective endocarditis.

Two-year longitudinal changes in forearm cortical bone geometry in postmenopausal women with mild primary hyperparathyroidism without parathyroidectomy

Several studies suggest that mild PTH excess does not have any deteriorative effects on bone mineral density (BMD) in several-year-longitudinal studies of patients with mild primary hyperparathyroidism (pHPT) without parathyroidectomy (PTX). However, it remains unknown about the change in bone geometry in pHPT patients without PTX. We examined the longitudinal effects of mild PTH excess on cortical bone geometry in postmenopausal patients with mild pHPT without PTX by using peripheral quantitative computed tomography (pQCT), and we compared them with normal and hypoparathyroidism women. Nine postmenopausal female patients who were diagnosed as pHPT, six postmenopausal female patients with hypoparathyroidism (3 idiopathic and 3 postoperative), and thirty postmenopausal control subjects participated in this study. Radial volumetric (v) BMD and several bone geometry parameters were measured by pQCT at basal line and after 2 years. Cortical vBMD was significantly lower in pHPT group. Moreover, total area and periosteal circumferences were significantly higher in pHPT group. Total and cortical vBMD were significantly decreased after 2 years in control group. However, they were stable in pHPT group after 2-year follow-up. As for bone geometry, cortical thickness and area were also stable in pHPT group during 2-year follow-up, although they were significantly reduced in control group and hypoparathyroidism group. In conclusion, the present longitudinal study revealed that there were no significant changes in radial vBMD and cortical bone geometry in postmenopausal women with mild pHPT, whereas age-related thinning of cortical bone as well as decrease of vBMD were observed in the control and patients with hypoparathyroidism.

Demonstration of mother-to-child transmission of Streptococcus mutans using multilocus sequence typing

A new reliable genotyping method, multilocus sequence typing (MLST), was used to evaluate vertical transmission of the cariogenic pathogen Streptococcus mutans. A total of 136 S. mutans strains were isolated from saliva samples of 20 Japanese mother-child pairs, including 5 girls and 5 boys with primary dentition, and 5 girls and 5 boys with mixed dentition. The nucleotide sequences of 8 partial housekeeping genes, aroE, murI, gltA, glnA, glk, tkt, lepC, and gyrA, were analyzed and a similarity for all of those sequences between strains from a mother-child pair was regarded as indicating transmission, which was shown in 70% of the pairs. Interestingly, the rate of transmitted strains from mothers was significantly higher in the girls (90%) than in the boys (p = 0.001). Furthermore, the S. mutans sequence type (ST) with the highest distribution percentage in each maternal saliva sample was found to be transferred to their children. In addition, variations in two large conjugative-transfer associated regions, TnSmu1 and TnSmu2, were determined and compared with the STs defined by MLST. No variations in those two regions shown by PCR patterns were present in any of the strains isolated from the same families with the same STs, though isolates of some STs from different families showed distinct patterns for TnSmu2. Our results indicate that mothers are the main source for transmission of S. mutans to their children, while the present MLST method was also shown to be useful for investigating bacterial transmission.

Distribution of Porphyromonas gingivalis fimA genotypes in cardiovascular specimens from Japanese patients

INTRODUCTION

Porphyromonas gingivalis, a major periodontal pathogen, is gaining increasing attention for its possible association with cardiovascular diseases. Its fimbriae are classified into six genotypes (types I-V and Ib) based on the diversity of the fimA genes encoding the fimbrial subunits. In this study, fimA genotypic distribution was analyzed in P. gingivalis-infected cardiovascular specimens.

METHODS

A total of 112 heart valves and 80 atheromatous plaque specimens were collected from patients undergoing cardiovascular surgery, as well as 56 dental plaque specimens. Bacterial DNA was extracted from each, and polymerase chain reaction analysis was carried out with a P. gingivalis-specific set of primers. P. gingivalis-positive specimens were further analyzed to discriminate the fimA genotype using polymerase chain reaction with fimA type-specific primer sets.

RESULTS

P. gingivalis was detected in 10.4% of the cardiovascular specimens and 50.0% of the dental plaque samples. In the latter, type II was most frequently detected (35.7%), followed by types I (28.6%) and IV (21.4%), while types IV and II were detected with considerable frequencies of 45.0% and 30.0%, respectively, in the cardiovascular specimens. In contrast, the occurrence of type I was limited (5.0%) in the cardiovascular specimens.

CONCLUSION

These results suggest that specific fimA genotypic clones, which are reportedly associated with periodontitis, are also frequently harbored in cardiovascular specimens, indicating the possible involvement of type II and IV clones in the initiation and progression of cardiovascular diseases.

Heterogenic virulence and related factors among clinical isolates of Porphyromonas gingivalis with type II fimbriae

BACKGROUND/AIMS

Porphyromonas gingivalis is a periodontal pathogen whose fimbriae are classified into six genotypes (types I-V and Ib) based on the diversity of the fimA genes encoding the fimbrial subunits. Accumulated evidence suggests that P. gingivalis strains with type II fimbriae are more virulent as compared to those with other types. However, it is unknown if strong virulence is uniformly conserved among clones with type II fimbriae. In the present study, we compared infectious inflammatory changes in clinical isolates of P. gingivalis with type II fimbriae using a mouse abscess model to examine their pathogenic heterogeneity and heterogeneity-related factors.

METHODS

Suspensions of nine different clinical isolates with type II fimbriae were subcutaneously injected into female BALB/c mice and inflammatory parameters, such as serum sialic acid concentration, were compared.

RESULTS

Many of the type II fimbrial isolates caused severe inflammation in the mice, though some were less causative, as was the control strain ATCC 33277 (type I fimbria strain). These results showed that pathogenic heterogeneity exists among P. gingivalis clones with type II fimbriae. Further, the heterogeneity-related factors of P. gingivalis strains were analyzed and the pathogenic potentials showed positive relationships to gingipain activities and invasive efficiency but not to hydrophobicity or autoaggregation. In addition, invasive efficiency was related to the activities of gingipains that were extracellularly secreted.

CONCLUSION

These results suggest that pathogenic heterogeneity has relationships with the invasive and proteolytic activities of P. gingivalis clones with type II fimbriae.

Detection and serotype distribution of Actinobacillus actinomycetemcomitans in cardiovascular specimens from Japanese patients

Actinobacillus actinomycetemcomitans, an important pathogen in periodontitis, has also been detected in cardiovascular tissues. Sixty heart valves were collected during valve replacement surgery from 60 patients (one from each), 10 were from patients with infective endocarditis (IE group) and 50 were from patients with other valvular diseases (non-IE group). In addition, 46 samples of aneurysmal tissue were taken from 46 patients with a thoracic or abdominal aneurysm (Aneurysm group, one from each). Dental plaque samples were taken from 54 of the patients, 31 in the IE and non-IE groups and 23 in the aneurysm group. First, the distribution of A. actinomycetemcomitans in all specimens was analysed using a polymerase chain reaction method, which resulted in a positive reaction in 33 (31.1%) of the cardiovascular specimens and 25 (46.3%) of the dental plaque samples. Next, using serotype-specific sets of primers, the serotype distribution of A. actinomycetemcomitans in the cardiovascular specimens and dental plaque samples was found to be significantly different compared to dental plaque samples from Japanese subjects reported previously.