Increased systemic levels of inflammatory mediators following one-stage full-mouth scaling and root planing.

BACKGROUND AND OBJECTIVE: Full-mouth scaling and root planing (FM-SRP) acts as a potent inflammatory stimulus immediately after treatment; however, systemic inflammation typically improves in the long term. The contribution of FM-SRP to systemic biological and acute-phase responses is largely unknown. The purpose of this prospective intervention study was to assess the systemic and local biological responses after FM-SRP. MATERIAL AND METHODS: Thirty-one patients with generalized moderate-to-severe chronic periodontitis received 1-stage FM-SRP. Measurement of clinical parameters and body temperature as well as collection of subgingival plaque, peripheral blood and gingival crevicular fluid was performed before and after treatment 2 or 3 times. Quantification of periodontopathic bacteria in the sulcus and measurement of corresponding serum IgG titers were performed. Systemic and local inflammatory markers such as endotoxin, high-sensitive C-reactive protein (hs-CRP) and 6 inflammatory cytokines were assessed using high-sensitivity assays. RESULTS: Compared to baseline values, FM-SRP resulted in a substantial improvement in clinical parameters (P < .05), lower bacterial counts (P < .01) and a significant decrease of IgG titers against Porphyromonas gingivalis (P < .001) 6 weeks after treatment. Comparing baseline parameters to those at 1 day post-treatment, there was a statistically significant elevation in body temperature (P = .007). In addition, a 5-fold increase in hs-CRP (P < .001), a remarkable increase in interferon-γ (P < .001) and a slight increase in interleukin (IL)-12p70 (P = .001) were detected in serum samples. In the gingival crevicular fluid, marked increases in hs-CRP (P < .001), IL-5 (P = .001), IL-6, IL-12p70 and tumor necrosis factor-α (P < .001 for the latter 3 markers) were noted 1 day after treatment. Endotoxin levels were below measurable limits for most time points. CONCLUSION: FM-SRP resulted in clinical and microbiological improvement 6 weeks post-treatment, but produced a moderate systemic acute-phase response including elevated inflammatory mediators 1 day post-treatment.

Full-mouth scaling and root planing combined with azithromycin to treat peri-implantitis.

BACKGROUND: Full-mouth scaling and root planing combined with azithromycin is clinically and bacteriologically effective for the treatment of chronic periodontitis. This study aimed to investigate the clinical and bacteriological effects of this combination treatment in patients with peri-implantitis. METHODS: Twenty adult patients with both chronic periodontitis and peri-implantitis were randomly divided into two groups (10: test, 10: control). All patients underwent full-mouth scaling and root planing but the test group received azithromycin for 3 days before the procedure. The probing depth, bleeding on probing, and the gingival index were assessed clinically. Bacterial samples were obtained before treatment at 1 week and 1, 3, 6, 9 and 12 months after treatment. Quantitative and qualitative analyses were performed using the polymerase chain reaction Invader method. RESULTS: All clinical parameters showed better improvement in both periodontitis and peri-implantitis in the test group. Periodontal bacteria were more effectively reduced in the test group, but gradually increased around implants 6 months after treatment and natural teeth 9 months after treatment. CONCLUSIONS: Full-mouth scaling and root planing combined with azithromycin was temporarily useful for the treatment of peri-implantitis. Clinical improvements were maintained for about 9 months but periodontal bacteria increased again 6 months after treatment.

Regular conductance fluctuations indicative of quasi-ballistic transport in bilayer graphene.

Quasi-periodic conductance fluctuations are observed in the low-temperature magneto-conductance of a bilayer graphene sample. The quasi-periodic nature of the fluctuations is confirmed by their Fourier power spectrum, which consists of just a small number of dominant frequency components. From an experimental study of these features, which are highly reminiscent of those reported previously for ballistic semiconductor quantum dots, we suggest that they are associated with the formation of an open quantum dot in the submicron graphene sample.

Degradation of noncollagenous components by neutrophil elastase reduces the mechanical strength of rat periodontal ligament.

BACKGROUND AND OBJECTIVE: We have previously shown that increases in neutrophil elastase in periodontal ligament with chronic periodontitis results in degradation of the noncollagenous components. The purpose of this study was to investigate whether the destruction of noncollagenous components by treatment with elastase in vitro causes changes in the mechanical properties of the periodontal ligament. MATERIAL AND METHODS: The transverse sections of mandibular first molars, prepared from male Wistar rats at 6 wk of age, were digested with 0-50 microg/mL of neutrophil elastase at 37 degrees C for 4 h. Then, their mechanical properties and morphological features were examined. RESULTS: Digestion with elastase dose-dependently decreased the maximum shear stress and failure strain energy density of the periodontal ligament (p < 0.05-0.01). The histological observations after digestion revealed marked degradation of oxytalan fibers, but no marked changes of the collagen fibers, which was confirmed by the detection of very low quantities of hydroxyproline in the digest. The light and scanning electron micrographs showed that the elastase degraded the interfibrillar substances in the periodontal ligament and exposed individual collagen fibrils. CONCLUSION: These results suggest that the increased neutrophil elastase observed in periodontal disease degrades the oxytalan fibers and interfibrillar substances in the periodontal ligament to decrease its mechanical strength.

Neutrophil elastase is involved in the initial destruction of human periodontal ligament.

BACKGROUND AND OBJECTIVE: It has been reported that noncollagenous proteins may provide mechanical strength to the periodontal ligament. Several proteolytic activities, including that of neutrophil elastase, are reported to increase significantly in periodontal disease. The aim of this study was to investigate the function of neutrophil elastase in the initial destruction of periodontal ligament at early stages of periodontal disease. MATERIAL AND METHODS: The detection and identification of proteinases in chronic periodontitis and healthy periodontal ligament were examined by zymographic and zymo-Western analysis. The morphological changes of periodontal ligament, digested with or without authentic proteinases, were observed using scanning electron microscopy. RESULTS: Increases in neutrophil elastase, plasminogen, and matrix metalloproteinase-9 were detected in periodontal ligament from chronic periodontitis, compared with healthy periodontal ligament. Among these proteinases, only neutrophil elastase digested the intact noncollagenous proteins of periodontium. When human healthy periodontal ligament was directly digested by neutrophil elastase in an in vitro system, the morphological features were quite similar to that of the periodontal ligament in chronic periodontitis . In healthy periodontal ligament, the collagen fibrils are covered with noncollagenous proteins containing 110 kDa acidic glycoprotein, which was degraded initially by the neutrophil elastase. CONCLUSION: It was concluded that neutrophil elastase is involved in the degradation of noncollagenous protein-covered collagen fibrils in the early destructive stages of periodontal disease.

Immunoblot detection and expression of enamel proteins at the apical portion of the forming root in porcine permanent incisor tooth germs.

There have been many immunohistochemical studies of enamel proteins during root formation. In the present article, the detection and expression of enamel proteins in tissue samples prepared from the apical portion of the forming root (APFR) in porcine permanent incisor tooth germs were studied. Amelogenin, enamelin, and sheathlin were detected by immunoblot analysis, but only in small amounts. The detection of their derivatives indicated their degradation. It is, at present, unclear as to which proteinases are involved in these degradations, because activity of enamel matrix serine proteinase 1 and enamelysin was not detected on gelatin and casein zymograms. The expression of enamel proteins was also proved in the APFR sample by the detection of polymerase chain reaction products of their cDNAs, and this may be related to cells of fragmentized Hertwig's epithelial root sheath. Amelogenin expression was not greater than that of enamelin and sheathlin. It was different from the expression pattern of secretory ameloblasts involved in enamel matrix formation. These results suggest that the amelogenins found in the APFR do not form a three-dimensional structure of amelogenin micelles, which has been proposed for the secretory enamel matrix structure. In this case, the enamel proteins could spread out easily following degradation into the matrix of future cementum. Some of their derivatives may play a role in the formation of the cementum.

Proteome analysis of Oncorhynchus species during embryogenesis.

To understand the molecular mechanisms underlying normal and abnormal development of two salmonids, masu salmon (Oncorhynchus masou) and rainbow trout (O. mykiss), we used two-dimensional (2-D) electrophoresis to construct a series of 2-D maps during the embryonic period. We identified all visible protein spots on the 2-D map by assigning numbers for masu salmon and rainbow trout, and we determined N-terminal sequences of proteins for one hundred of the spots, that appear at very high concentrations in the whole embryos of masu salmon and rainbow trout. We also characterized embryonic stages according to the periods of appearance of spots. Most of the N-terminal sequences were identical or at least highly similar to partial sequences reported for vitellogenin (Vtg) of O. mykiss. A potential proteolytic processing of Vtg for rainbow trout is discussed in relation to the time of appearance and relative position of Vtg fragments within the complete protein sequence.

Evidence for substance P as an endogenous substance causing cough in guinea pigs.

We examined an endogenous substance causing cough in awake guinea pigs. An intraperitoneal injection of phosphoramidon, a selective inhibitor of neutral endopeptidase (E.C. 3.4.24.11), caused cough in a dose-dependent fashion for approximately 40 min. At a dose of 3 x 10(-3) mol/kg, phosphoramidon caused a total of 11.6 +/- 1.4 coughs in 40 min. Phosphoramidon (3 x 10(-3) mol/kg)-induced cough was significantly inhibited by systemic pretreatment with capsaicin (p < 0.01). Aerosols of FK 888 (1 min), a specific inhibitor of substance P (NK1) receptor, inhibited phosphoramidon (3 x 10(-3) mol/kg)-induced cough in a dose-dependent fashion with complete inhibition at a dose of 10(-5) M. Likewise, aerosols of FK 224 (10(-5) M; 1 min), another inhibitor of NK1 and NK2 receptors, or lidocaine (4%, 1 min) significantly inhibited phosphoramidon (3 x 10(-3) mol/kg)-induced cough (p < 0.01). Furthermore, aerosols of FK 888 (10(-5) M; 1 min) significantly inhibited cough induced by cigarette smoke in awake guinea pigs (p < 0.01). These results suggest that substance P released from sensory nerves in the airway may be an endogenous substance causing cough and the substance P antagonist may be the drug for treatment of cough in respiratory disease.

Bradykinin-induced cough reflex markedly increases in patients with cough associated with captopril and enalapril.

We studied the effects of angiotensin converting enzyme (ACE) inhibitors on cough responses to bradykinin (BK), substance P (SP) and citric acid in a double blind, random study on 10 hypertensive patients receiving ACE inhibitors. Of these patients, five had reported cough with ACE inhibitors. Cough responses to citric acid were similar between patients with and without cough, and SP up to 10(-5) M did not cause cough in any of the subjects. BK caused cough at 13.4 +/- 1.2 (-log M) in 5 patients with cough associated with ACE inhibitors, but it did not cause cough at concentrations up to 10(-5) M in other 5 patients. One month after the withdrawal of ACE inhibitors, 5 patients were free from cough symptoms, and BK did not cause cough up to 10(-5) M in these patients, except for one who coughed at 10(-9) M, without changes in responses to citric acid. BK caused cough at 14.3 +/- 0.7 (-log M) although BK1-7, a major metabolite of BK by ACE, caused cough at 5.7 +/- 0.7 (-log M) in another 3 patients with cough associated with ACE inhibitor. These results suggest that impaired metabolism of BK induced by ACE inhibitors may relate to the manifestation of cough in hypertensive patients receiving ACE inhibitors.

Studies on the castability of Co-Cr alloy for cast plates. Part 2: Effect of form of sprue attachment to the wax pattern.

Co-Cr alloy is used more frequently than Ni-Cr alloy as a non-precious alloy for cast plates in Japan. However, since the melting point of Co-Cr alloy is very high, about 1300 degrees C, and since it oxidizes easily, a vacuum-pressure casting machine capable of melting this alloy in a reducing atmosphere has recently been developed. Using this vacuum-pressure casting machine, the authors studied the effects on the castability of Co-Cr alloy due to the form of sprue attachment to the wax pattern. The results clarified that in the vacuum-pressure casting method, the form of sprue attachment to the wax pattern has a significant effect (p less than 0.01) on the castability of Co-Cr alloy.