Omics-Based Mathematical Modeling Unveils Pathogenesis of Periodontitis in an Experimental Murine Model.

Periodontitis is a multifactorial disease that progresses via dynamic interaction between bacterial and host-derived genetic factors. The recent trend of omics analyses has discovered many periodontitis-related risk factors. However, how much the individual factor affects the pathogenesis of periodontitis is still unknown. This article aims to identify multiple key factors related to the pathogenesis of periodontitis and quantitatively predict the influence of each factor on alveolar bone resorption by omics analysis and mathematical modeling. First, we induced periodontitis in mice (n = 3 or 4 at each time point) by tooth ligation. Next, we assessed alveolar bone resorption by micro-computed tomography, alterations in the gene expression by RNA sequencing, and the microbiome of the gingivae by 16S ribosomal RNA sequencing during disease pathogenesis. Omics data analysis identified key players (bacteria and molecules) involved in the pathogenesis of periodontitis. We then constructed a mathematical model of the pathogenesis of periodontitis by employing ordinary differential equations that described the dynamic regulatory interplay between the key players and predicted the alveolar bone integrity as output. Finally, we estimated the model parameters using our dynamic experimental data and validated the model prediction of influence on alveolar bone resorption by in vivo experiments. The model predictions and experimental results revealed that monocyte recruitment induced by bacteria-mediated Toll-like receptor activation was the principal reaction regulating alveolar bone resorption in a periodontitis condition. On the other hand, osteoblast-mediated osteoclast differentiation had less impact on bone integrity in a periodontitis condition.

Feasibility of photon-counting spectral CT in dental applications-a comparative qualitative analysis.

PURPOSE: The goal of this study was to demonstrate the feasibility of using photon-counting spectral CT for dental applications. This paper qualitatively analyzes the visibility of accessory canals (ACs) and metal artefacts from dental implants for cone-beam CT (CBCT), microtomography (microCT), and photon-counting spectral CT (PCSCT). MATERIALS AND METHODS: All of the teeth in this study were extracted, and eight teeth in total were scanned on a CBCT scanner, a microCT scanner and on a PCSCT scanner. Six of the teeth that were scanned have accessory canals, one has a titanium rod attached to it, and one has a gutta-percha point inside it. Qualitative analysis was done to compare the different imaging modalities. RESULTS: The subjective image analysis demonstrated similar performance in AC detection and visualisation for PCSCT and CBCT (p value >0.05). Both PCSCT and microCT performed similarly for metal artefact reduction, and both were superior to CBCT (p value <0.05). CONCLUSION: Although microCT provides detailed information about small anatomical structures, it is not suitable for in vivo use. However, the PCSCT scanner was able to detect small anatomical structures in teeth comparable to CBCT, as well as being superior in reducing metal artefacts from dental implants. This study showed that PCSCT is a promising modality for future dentistry applications.

Cooperation of phosphate monomer and silica modification on zirconia.

Ceramic restorations with resin-based adhesive systems have been the focus of recent attention in clinical dentistry. Yttrium-oxide-partially-stabilized zirconia (YPSZ) ceramics have optimized physical properties and exhibit favorable fracture toughness, though their bonding properties are problematic. Although functional phosphate monomers and silica-coating by tribochemical modification were expected to improve the bonding properties between YPSZ ceramics and resin-based adhesives, these two methods remain controversial. This study evaluated the efficiency of silica-coating by tribochemical modification of YPSZ ceramics. The application of phosphate monomer and a silane coupling agent on silica-coated YPSZ was also investigated. The silica-coating of YPSZ ceramics by tribochemical modification was not efficient, given the higher mechanical toughness of the densely sintered ceramics. Stable shear bond strength was achieved on silica-coated YPSZ ceramics with the cooperative interaction of phosphate monomer and silane coupling.

Tetrahymena actin: copolymerization with skeletal muscle actin and interactions with muscle actin-binding proteins.

We have previously shown that actin from Tetrahymena pyriformis has a very divergent primary structure (Hirono, M., Endoh, H., Okada, N., Numata, O., & Watanabe, Y. (1987) J. Mol. Biol. 194, 181-192) and that though it shares essential properties with skeletal muscle actin, it does not interact at all with phalloidin or DNase I (Hirono, M., Kumagai, Y., Numata, O., & Watanabe, Y. (1989) Proc. Natl. Acad. Sci. U.S. 86, 75-79). In this study, we investigated the copolymerization of this actin with skeletal muscle actin by direct observation of the heteropolymers formed from the two actins by means of electron microscopy. We also examined the binding of actin-binding proteins from skeletal muscle or smooth muscle to Tetrahymena actin by means of a cosedimentation assay. The results show that (i) Tetrahymena actin copolymerizes with skeletal muscle actin and that (ii) muscle myosin subfragment 1 binds to it in the absence of ATP, like skeletal muscle actin. However, it was also shown that (iii) muscle alpha-actinin hardly binds to Tetrahymena actin and that (iv) muscle tropomyosin does not bind to it at all. The results show that Tetrahymena actin has both properties similar and dissimilar to those of skeletal muscle actin.

Rapid and gentle extraction, reconstitution and characterization of microfilament and glia filament from rat astrocytes.

We developed gentle and rapid methods for depolymerization and extraction of both microfilament and glia filament separately from a crude cytoskeletal fraction of rat astrocytes. Electron microscopy revealed that the filament reconstituted from the microfilament extract closely resembled F-actin that was formed from G-actin of rabbit skeletal muscle. It was found by immunoblotting analysis that even the reconstituted microfilament-like filaments, which had been purified by affinity chromatography with heavy meromyosin subfragment 1 (S1)-conjugated Sepharose, contained vimentin and glia fibrillary acidic protein (GFAP) besides actin, inferring the interaction between microfilament and glia filament. The filaments (9-10 nm thick) reconstituted from the glia filament extract were composed of actin and other minor components in addition to vimentin and GFAP. Actin, GFAP, 101, 34, 32.5, 30.5, 29.5 and 28 kDa proteins found in the reconstituted glia filament-like filaments were suggested to be glia filament-associated proteins.

Suppression by gangliosides of polymerization of glial cytoskeletons prepared from rat astrocytes: a role of sialic acid moiety.

This study investigated in vitro the effects of gangliosides on polymerization of either the depolymerized microfilament preparation (MF) or depolymerized glia filament preparation (GF) extracted separately from the crude cytoskeletal fraction of rat astrocytes. Gangliosides GM1, GM2 and GM3 markedly suppressed polymerization of both MF and GF. The concentration of GM1, GM2 or GM3 required to induce 50% inhibition of the polymerization of 7.5 micrograms MF protein/200 microliters (IC50 of GM1, GM2, or GM3) was 3.2, 2.8 or 5.6 micrograms/200 microliters, respectively. The IC50 of each ganglioside for the polymerization of 7.5 micrograms/200 microliters of GF, furthermore, was 3.3, 3.5 or 7.4 micrograms/200 microliters, respectively, suggesting that the inhibitory activities of GM1 and GM2 on polymerization of both MF and GF were greater than those of GM3. GM1, GM2 and GM3 also suppressed dose-dependently the polymerization of both actin and vimentin. The inhibitory activities of GM1 and GM2 on the polymerization of actin or vimentin were greater than GM3, as in the case of polymerization of MF or GF. The IC50S of GD1a and GT1b for MF polymerization at the same concentration were 2.2 and 1.2 micrograms/200 microliters, respectively, and those for GF polymerization were 2.7 and 1.7 micrograms/200 microliters, respectively. The IC50 of GD3 for MF polymerization was 3.9 micrograms/200 microliters, and that for GF polymerization 4.0 micrograms/200 microliters, implying that the inhibitory activities of GD3 on polymerization of both MF and GF were greater than those of GM3. The findings suggested that the inhibitory activities of gangliosides on MF or GF polymerization became greater with increasing number of sialic acid residues. AsialoGM1 suppressed neither MF nor GF polymerization, and inhibited dose-dependently the ability of GM1 to suppress MF polymerization.

Postsynaptic density visualized by whole mount electron microscopy.

Detergent-unextractable structures of synaptic plasma membrane of rat cerebrum were observed by whole mount electron microscopy. The globular structures were identified as postsynaptic densities (PSDs) from several criteria and appeared to consist of folded strings, to which a number of other molecules might be attached. Some of the globular structures were attached with subsynaptic webs. The structures contained a number of finely striated small strips (10-20 nm wide, 60-100 nm long), parts of which were peeled off from PSD cytoskeletal base by N-lauroyl sarcosinate.

Mutagenic activation of biliary metabolites of benzo(a)pyrene by beta-glucuronidase-positive bacteria in human faeces.

Human faeces hydrolysed synthetic beta-D-glucuronides of both p-nitrophenol and phenolphthalein. The origin of this activity in faeces was localised in the bacterial pellet fraction after centrifugation. Ninety-seven bacterial strains with beta-glucuronidase activity isolated from fresh human faeces were identified as species of Bacteroides, Peptostreptococcus, Fusobacterium, Propionibacterium, Clostridium, Eubacterium and Bifidobacterium. They were classified into two groups according to their activity against two synthetic beta-D-glucuronides. One group hydrolysed p-nitrophenyl glucuronide and phenolphthalein glucuronide to the same extent and the other hydrolysed p-nitrophenyl glucuronide much more strongly than phenolphthalein glucuronide. The bile of rats given benzo(a)pyrene by mouth was tested for mutagenicity in the presence and absence of cell-free extracts of human faeces and bacteria. Extracts of beta-glucuronidase-positive bacteria increased the mutagenicity of metabolites of benzo(a)pyrene, as did faecal extracts, but extracts of beta-glucuronidase-negative bacteria did not. D-Saccharic acid-1,4-lactone inhibited the increase in mutagenicity produced by the faecal extracts and extracts of beta-glucuronidase-positive bacteria except for Peptostreptococcus strains 204 and 952. These results indicate that some intestinal bacteria have beta-glucuronidases heterogenous in substrate specificity and that they may be involved in mutagenicity of benzo(a)pyrene in the intestinal tract.

Embolization of cerebral arteriovenous malformations achieved with polyvinyl alcohol particles: angiographic reappearance and complications.

BACKGROUND AND PURPOSE: The appropriate choice of embolic materials with respect to the permanency of obliterated nidi after embolization and complications related to the procedure is essential for safe and effective embolization of cerebral arteriovenous malformations (AVMs). Our purpose was to ascertain the recanalization and complication rates after AVM treatment with polyvinyl alcohol (PVA) particles. METHODS: Between 1988 and 1994, 36 AVMs were embolized with PVA particles at our institution. Follow-up angiographic findings and occurrence of complications during the embolization procedures were analyzed retrospectively. RESULTS: Complete obliteration of the nidus immediately after embolization was achieved in five patients, and 80% to 99% obliteration was attained in 12 patients. Fifty-one follow-up angiographic examinations were performed 1 week to 60 months (mean, 7 months) after embolization in 31 patients. An increase in nidal size was seen on 15 follow-up angiograms (29%) and a decrease was seen in seven (14%). In 28 of the 51 angiograms obtained more than 1 month after follow up (mean, 13 months), 12 (43%) showed AVM enlargement. In four (80%) of five cases of complete obliteration, nidi reappeared on follow-up angiograms. Hemorrhagic complications occurred in three cases and ischemic ones in seven. One patient (3%) died and five (14%) suffered persistent neurologic deficits. CONCLUSION: Embolization with PVA particles can produce significant volume reduction in AVM nidal size, but recanalization is a distinct possibility.

Radiologic and histopathologic evaluation of canine artery occlusion after collagen-coated platinum microcoil delivery.

BACKGROUND AND PURPOSE: Platinum coil embolization is one of the significant advances in interventional neuroradiologic techniques that has been introduced this decade. Our purpose was to evaluate the angiographic and histologic effects of collagen-coated platinum microcoil delivery in the canine artery. METHODS: We embolized the bilateral internal maxillary arteries of 18 dogs; one uncoated and one collagen-primed coil was used in each dog. We evaluated all coils by angiography, macroscopy, and scanning electron microscopy within 30 minutes of embolization. We then studied a proportional number of coated and collagen-primed coils at either 1 or 3 days, or 1, 2, 3, 4, 8, 12, or 16 weeks postoperatively. RESULTS: Six (33%) of 18 arteries embolized with uncoated coils were occluded 30 minutes after delivery, whereas 11 (61%) of 18 arteries treated with collagen-primed coils were occluded within 30 minutes of embolization. Late occlusion (3 weeks after embolization) occurred in 2 (25%) of 8 arteries embolized with untreated coils, and 6 (75%) of 8 arteries embolized with collagen-primed coils. We calculated differences in late occlusion rates by the chi2 (chi-square) test, and found these differences were significant (P=.04). Histologic findings of arteries embolized with unprimed coils revealed endothelial cell growth was limited to the organized thrombi 4 weeks after coil delivery. In contrast, endothelial cells grew directly on the collagen-primed coils 3 days postoperatively, and coils were completely covered by endothelial cells within 2 weeks. We found an organized thrombus in the inner space of coils in angiographically occluded arteries, a finding that was not evident in angiographically patent arteries. CONCLUSION: Collagen-coated platinum coils can produce rapid and stable occlusion of embolized vessels.

Physiological concentrations of human epidermal growth factor in biological fluids: use of a sensitive enzyme immunoassay.

A sandwich enzyme immunoassay for epidermal growth factor (EGF) has been developed which measures EGF concentrations in serum, urine, saliva, gastric and pancreatic juices without pretreatment. Sensitivity for human EGF is 500 fg/tube. Serum EGF concentration in normal males and females is 780 and 604 pg/ml, respectively. Urinary human EGF is 51.3 ng/mg creatinine for males, and 68.3 ng/mg creatinine for females. The difference is not significant, and no correlation between serum and urinary concentrations exists, but serum concentration changes with age. The highest concentration is seen up to 9 years of age, suggesting that EGF promotes cell proliferation during growth.

Long term results of ruptured aneurysms treated by coating.

We report the long term results of the treatment of 23 intracranial ruptured aneurysms by coating. Twenty-three patients treated by coating were followed for a mean period of 11.2 years. The mean interval between the last hemorrhage and the operation was 22.4 days. Ten aneurysms underwent total coating, 9 with Biobond and 1 with Aron Alpha. Thirteen aneurysms underwent partial coating, 11 with Biobond and 2 with Aron Alpha. Six aneurysms were reinforced partially by other materials, but no aneurysm was wrapped totally with these materials. Rebleeding occurred in 6 patients, of whom 5 died. The mean interval between coating and rebleeding was 4 years. All patients suffering rebleeding had been treated with Biobond, and 3 patients had undergone total coating of aneurysms. The risk of recurrent hemorrhage after total coating with Biobond was 33%. One rebleeding patient underwent a second operation 10.5 years after total coating of the aneurysm. Biobond was found only at the tip of the aneurysmal sac. From these results, reinforcement of ruptured aneurysms with Biobond seems to be of little value, and a more reliable method must be developed for aneurysms that cannot be clipped.

Targeting chemotherapy for malignant brain tumor using thermosensitive liposome and localized hyperthermia.

Thermosensitive liposomes are microscopic vesicles that can contain drugs and release them effectively in response to hyperthermia. To deliver an antitumor drug specifically to brain tumor, the authors used thermosensitive liposomes containing cis-diamminedichloroplatinum (CDDP) in conjunction with localized brain heating. The authors then investigated the antitumor effect on rat malignant glioma. Rous sarcoma virus-induced malignant glioma cells were transplanted into the brains of Fisher rats. Ten days after tumor inoculation, the rats were assigned to one of six treatment groups: control, free CDDP, hyperthermia, free CDDP + hyperthermia, liposomes containing CDDP (CDDP-liposome), and CDDP-liposome + hyperthermia. Liposomes containing CDDP or free CDDP were injected via the tail vein. Brain tumor heating was administered by means of a radiofrequency antenna designed at our institute. The rats treated with CDDP-liposome + hyperthermia had the longest survival time and the tumor CDDP level of this group was the highest when compared to the other groups. Histopathological examination showed that tumor cells were necrotized but surrounding normal brain tissue remained undamaged. On the basis of these findings we suggest that the combination of thermosensitive liposome and localized hyperthermia may better focus antitumor drugs to the tumor, providing a significantly greater antitumor effect.

Inhibition of experimental bone resorption and osteoclast formation and survival by 2-aminoethanesulphonic acid.

It is known that bone resorption is mediated by osteoclasts, and lipopolysaccharide (LPS) and inflammatory mediators such as interleukin-1 (IL-1) and prostaglandin E2 (PGE2) induce osteoclast differentiation from haemopoietic cells, 2-aminoethanesulphonic acid, which is known as taurine, is an important nutrient and is added to most synthetic human infant milk formulas. In this study, it was found that 2-aminoethanesulphonic acid inhibits the stimulation of bone resorption mediated by LPS of the periodontopathic microorganism Actinobacillus actinomycetemcomitans Y4 in organ cultures of newborn mouse calvaria. The effect of 2-aminoethanesulphonic acid on the development and survival of osteoclast-like multinucleated cells produced in a mouse bone-marrow culture system was also examined. 2-aminoethanesulphonic acid (100 microg/ml) suppressed the formation of these osteoclast-like cells in the presence of LPS of A. actinomycetemcomitans Y4, IL-1alpha or PGE2 in mouse marrow cultures. On the other hand, 2-aminoethanesulphonic acid did not inhibit 1alpha, 25-dihydroxyvitamin D3-mediated osteoclast differentiation. Although IL-1alpha elongated the survival of the osteoclast-like cells, 2-aminoethanesulphonic acid blocked the supportive effect of IL-1alpha on osteoclast survival. 2-aminoethanesulphonic acid showed no effect on the growth of mouse osteoblasts. Finally, it was found that 2-aminoethanesulphonic acid inhibited alveolar bone resorption in experimental periodontitis in hamsters. These results suggest that 2-aminoethanesulphonic acid is an effective agent in preventing inflammatory bone resorption in periodontal diseases.

Disappearance of a tumor shadow fed by the tentorial artery after embolization of the external carotid artery.

The tentorial artery is a branch of the meningohypophyseal trunk originating from the internal carotid artery; this artery sometimes becomes an enlarged feeding artery in patients with tentorial lesions, especially tentorial meningiomas. We experienced a case of a cerebellopontile angle meningioma whose angiogram revealed the disappearance of a feeding artery arising from the tentorial artery after embolization of the external carotid artery. We report this case and discuss the mechanism of this phenomenon.

Experimental study of materials for patch graft on right ventricular outflow tract under extracorporeal circulation in dogs--comparison between Denacol EX-313-treated bovine jugular vein graft and expanded polytetrafluoroethylene (EPTFE) graft.

A comparison between a bovine jugular vein treated with a hydrophilic polyepoxy compound cross-linker (Denacol), and expanded polytetrafluoroethylene (EPTFE), an artificial material, as a patch graft for the reconstruction of the right ventricular outflow tract under extracorporeal circulation in dogs, as if they had pulmonic stenosis, was made. Hemodynamic and histological examinations were conducted two weeks after the transplantation. Hemodynamic problems were not observed in either the Denacol or EPTFE groups. Macroscopically, organization of new tissue on the graft surface was more marked in the EPTFE group than in the Denacol group, and newly-formed tissue was seen surrounding the border of the graft and burying it in the EPTFE group. In the Denacol group, microscopic findings revealed the presence of inflammatory cells and fibroblasts, and an invasion of the graft by collagen fibers and elastic fibers. In the EPTFE group, there was minimal cellular infiltration of the graft and a thick layer consisting of collagen fibers and fibroblasts was observed around the graft. These results indicated that two weeks after transplantation the graft was better assimilated and organized with blood vasculature in the patch graft in the Denacol group than in the EPTFE group.

Postnatal transfer of PCBs from exposed mothers to their babies: influence of breast-feeding.

Polychlorinated biphenyl (PCB) concentrations in the blood of mothers who were occupationally exposed to PCBs in a capacitor manufacturing facility, and their children, were analyzed from 1975 to 1979. The factory terminated PCB use in 1972, and environmental PCBs were eliminated artificially. Despite this, blood PCB levels of the mothers were very high, i.e., 10-100 times higher than that of non-occupationally exposed persons. In a previous report, we discussed the relationship between breast-feeding and PCB levels in the blood. This relationship is confirmed further by the present investigation which continued during a 5-yr period. The PCB levels in blood of children were influenced greatly by the duration of breast-feeding, but showed little relationship to the PCB levels in maternal blood. The PCB exposure period of the mothers, time of birth, and age of the children were less clearly related to the PCB levels in the children. The PCB concentration in the children's blood decreased at a constant rate and was independent of their blood PCB levels. A similar result was noted for their mothers' PCB levels. A slight difference, however, was found in the rate of decrease of blood PCB levels between the mothers and children. The results of questionnaire research on the health conditions and the medical examinations for the children showed that frequency of complaints, e.g., red eye, fever, itchy skin, and carious teeth, related favorably to the duration of breast-feeding. Less severe findings, i.e., decay of nails, pigmentation, mottled enamel, carious teeth, which were typical symptoms in yusho patients, were observed in some children. They were not, however, diagnosed as having PCB poisoning inasmuch as medical treatments were unnecessary.

[Levofloxacin concentrations in serum, sputum and lung tissue: evaluation of its efficacy according to breakpoint].

The levels of levofloxacin (LVFX) in the serum, sputum and lung tissue were measured by a high-performance liquid chromatography method, and the penetration ratio of LVFX into respiratory tissue was investigated. The subjects of this study were 23 patients under pulmonectomy or brochoscopy. LVFX at the dose of 200 mg was given orally and specimens were collected as follows; serum at 2, 3 and 5 hours after, sputum at 2 hours after, and lung tissue at 3 and 5 hours after the administration, respectively. The mean level of LVFX in lung tissue at 3 hours was 3.91 +/- 2.33 micrograms/g, and those in sputum and in serum at 2 hours were 0.71 +/- 0.63 and 2.08 +/- 1.01 micrograms/ml, respectively. A very strong correlation was demonstrated between the level of LVFX in lung tissue and that in serum (p < 0.0001), but correlation between those in sputum and in serum was not significant. The penetration ratio of LVFX into lung tissue was 217.2% and that into sputum was 4.05%. Based on the results of this study, the breakpoints (BPs) of LVFX for pneumonia and chronic respiratory tract infections were calculated to be 4 micrograms/ml and 1 microgram/ml, respectively. It was concluded that penetration of LVFX into lung tissue was satisfactory, and the tissue level of LVFX exceeded greatly the MIC90s against the typical pathogenic bacteria of respiratory tract infections. Taking the excellent BP for pneumonia, 4 micrograms/ml, into consideration, it was thought that LVFX is an effective antibacterial agent against pneumonia and other respiratory tract infections.

[Liquid embolization for arteriovenous malformation with temporary balloon occlusion of another feeders].

A case of frontal arteriovenous malformation, embolized using a new balloon catheter technique, was reported. During liquid embolization of the main feeder from anterior cerebral artery, middle cerebral artery was temporary occluded with another balloon catheter, to decrease blood flow from branches of middle cerebral artery. About 90% of the AVM could be obliterated by this technique.

Effects of orthognathic surgery on pharyngeal airway and respiratory function during sleep in patients with mandibular prognathism.

The aim of this study was to determine changes in overnight respiratory function and craniofacial and pharyngeal airway morphology following orthognathic surgery. The subjects were 40 patients in whom mandibular prognathism was corrected by orthognathic surgery: a one-jaw operation in 22 patients and a two-jaw operation in 18 patients. Morphological changes were studied using cone beam computed tomography immediately before surgery and at more than 6 months after surgery, and the apnoea-hypopnoea index (AHI) was measured with a portable polysomnography system. Pharyngeal airway volume was decreased significantly after surgery, especially in the one-jaw operation group. AHI was not changed significantly after surgery in either group, although AHI in one patient in the one-jaw operation group was increased to 19 events/h. There was no significant change in pharyngeal airway morphology in that patient, but he was obesity class 1 and was 54 years old. In conclusion, some patients who are obese, have a large amount of mandibular setback, and/or are of relatively advanced age may develop sleep-disordered breathing after mandibular setback; a two-jaw operation should therefore be considered in skeletal class III patients who have such risks because it decreases the amount of pharyngeal airway space reduction caused by mandibular setback surgery.