Hypoxia-inducible factor-1α inhibits interleukin-6 and -8 production in gingival epithelial cells during hypoxia.

BACKGROUND AND OBJECTIVE: Hypoxia has been widely studied in inflammatory diseases as it can modulate the inflammatory response, mainly via the hypoxia-inducible factor (HIF). However, little is known about the effects of hypoxia and the role of HIF in the inflammatory responses to periodontitis. In this study, we focused on the gingival epithelium that is exposed to relatively low levels of oxygen. We investigated whether hypoxic conditions have an impact on inflammatory responses in human gingival epithelial cells (HGECs). MATERIAL AND METHODS: Pimonidazole HCl, which accumulates in hypoxic cells, was administered intraperitoneally to C57BL/6 mice with or without Porphyromonas gingivalis infection. Immunohistochemistry was then performed to detect the hypoxic cells in periodontal tissue. Immortalized HGECs were cultured under hypoxic conditions with or without interleukin (IL)-1ß, and the expression levels of IL-6 and IL-8 were measured by real-time reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay. HIF-1α expression was detected by western blotting. The DNA-binding activity of HIF-1α was determined by a DNA-binding enzyme-linked immunosorbent assay. The involvement of HIF-1α in the hypoxic response was examined by transfection with HIF-1α siRNA. RESULTS: Immunohistochemistry revealed pimonidazole HCl accumulation in the gingival epithelium of both normal and P. gingivalis-infected mice, with a slightly stronger signal in the P. gingivalis-infected mice than in the normal mice. The IL-1ß-induced IL-6 and IL-8 production by HGECs was suppressed under hypoxic conditions. HIF-1α accumulated during hypoxia, and this accumulation was further enhanced by IL-1ß treatment. The hypoxia-dependent suppression of IL-6 and IL-8 expression was reversed by treating the cells with HIF-1α siRNA. CONCLUSION: Our results suggest that the gingival epithelium is exposed to low oxygen tension in periodontal tissue and that this hypoxic condition modulates the local inflammatory response of gingival epithelial cells in an HIF-1α-dependent manner.

Evaluation of the Ca ion release, pH and surface apatite formation of a prototype tricalcium silicate cement.

AIM: To evaluate the Ca2+ -releasing, alkalizing and apatite-like surface precipitate-forming abilities of a prototype tricalcium silicate cement, which was mainly composed of synthetically prepared tricalcium silicate and zirconium oxide radiopacifier. METHODOLOGY: The prototype tricalcium silicate cement, white ProRoot MTA (WMTA) and TheraCal LC (a light-cured resin-modified calcium silicate-filled material) were examined. The chemical compositions were analysed with a wavelength-dispersive X-ray spectroscopy electron probe microanalyser with an image observation function (SEM-EPMA). The pH and Ca2+ concentrations of water in which the set materials had been immersed were measured, and the latter was assessed with the EDTA titration method. The surface precipitates formed on the materials immersed in phosphate-buffered saline (PBS) were analysed with SEM-EPMA and X-ray diffraction (XRD). Kruskal-Wallis tests followed by Mann-Whitney U-test with Bonferroni correction were used for statistical analysis (α = 0.05). RESULTS: The prototype cement contained Ca, Si and Zr as major elemental constituents, whereas it did not contain some metal elements that were detected in the other materials. The Ca2+ concentrations and pH of the immersion water samples exhibited the following order: WMTA = prototype cement > TheraCal LC (P < 0.05). All three materials produced Ca- and P-containing surface precipitates after PBS immersion, and the precipitates produced by TheraCal LC displayed lower Ca/P ratios than those formed by the other materials. XRD peaks corresponding to hydroxyapatite were detected in the precipitates produced by the prototype cement and WMTA. CONCLUSION: The prototype tricalcium silicate cement exhibited similar Ca2+ -releasing, alkalizing and apatite-like precipitate-forming abilities to WMTA. The Ca2+ -releasing, alkalizing and apatite-like precipitate-forming abilities of TheraCal LC were lower than those of the other materials.

Postoperative maxillary stability after Le Fort I osteotomy using a u-HA/PLLA system: three-dimensional analysis by surface superimposition based on virtual Le Fort I osteotomy.

The postoperative stability achieved with Le Fort I osteotomy (LFI) using bioabsorbable systems remains controversial. A new method - multipoint measurement method - was devised for detailed three-dimensional examination of postoperative stability following LFI, and the stability after LFI when using SuperFIXSORB-MX made of u-HA/PLLA was investigated. Thirty-one patients who underwent LFI using SuperFIXSORB-MX were evaluated retrospectively. The patients were divided into four malocclusion types: open bite, mandibular retrognathia, mandibular protrusion, and facial asymmetry. Seven maxillary reference points were measured three-dimensionally using computed tomography scans obtained preoperatively (T0), 4 days post-surgery (T1), and 1 year post-surgery (T2). Surgical changes (T1-T0) and the postoperative discrepancy (T2-T1) of the maxilla were analysed to evaluate postoperative stability by surface superimposition of the virtual LFI segments. Postoperative discrepancy was the largest for the facial asymmetry type, ranging from 0.75 ± 0.45 mm to 0.98 ± 0.52 mm in three-dimensional distance (minimum to maximum mean ± standard deviation values for the individual reference points). The relapse at U1 was 16% in the transverse axis, and the anterior nasal spine moved further upward by 17% of the amount of movement of the maxilla. Fixation with SuperFIXSORB-MX was considered to be within clinically acceptable limits.

Impact of the lateral skeletal stability following bilateral sagittal split ramus osteotomy for mandibular asymmetry.

This study evaluated the stability of bilateral sagittal split ramus osteotomy (BSSRO) associated with positional plagiocephaly and temporal and masseter muscles using posteroanterior cephalogram analysis and three-dimensional computed tomography (3D-CT). This retrospective cohort study included 31 patients who underwent BSSRO for mandibular asymmetry. The cranial vault asymmetry index (CVAI) and the cephalic index were used as indicators of positional plagiocephaly. The distance from the vertical reference line to the menton (Me) was measured on posteroanterior cephalograms immediately and 1 year after surgery, and postoperative stability was assessed. Temporal and masseter muscles were constructed from 3D-CT data and their volumes were measured. Simple regression analysis showed a significant correlation between postoperative changes in the vertical reference line to the Me and the CVAI (R = 0.56, p = 0.001), the amount of surgical movement in the vertical reference line to the Me (R = 0.41, p = 0.023), and the variable temporal muscle volume (R = 0.27, p = 0.028). There was no significant correlation between postoperative changes in the vertical reference line to the Me and the cephalic index (R = 0.093, p = 0.62) and variable masseter muscle volume (R = 0.16, p = 0.38). According to multivariate analysis, CVAI (p = 0.003) and amount of surgical movement in the vertical reference line to the Me (p = 0.014) were significant predictors of postoperative change in the vertical reference line to the Me. Positional plagiocephaly and amount of surgical movement influence lateral skeletal stability following BSSRO for mandibular asymmetry.

Randomized controlled trial to investigate how acrylic-based resilient liner affects on masticatory ability of complete denture wearers.

The aim of this study was to determine the effects of an acrylic-based resilient liner (ARL) on masticatory ability by verifying the null hypothesis that masticatory performance and mandibular movements do not differ between people who wear mandibular complete dentures with ARL and those who wear complete dentures with conventional acrylic resin (CAR). From April 2004 to July 2006, we conducted a randomized controlled trial study at two centres. After written informed consent was obtained from 74 edentulous patients, they were randomly allocated to either the ARL group or CAR group. Masticatory performance and mandibular movement at the lower incisal point during chewing were measured as the outcomes. We did not observe significant differences in both outcomes between the groups. The chewing cycles were significantly different during the initial, middle, and final phases of mastication. Within the limitations of the current study, the results indicate that the acrylic-based resilient denture liners used have no clinical impact on the masticatory ability of complete denture wearers.

Application of an open position splint integrated with a reference frame and registration markers for mandibular navigation surgery.

Navigation surgery plays an important role in modern craniomaxillofacial surgery, but it is difficult to apply navigation surgery to the mandible, due to its mobility. At present, headbands or headpins are widely used for fixation of the reference frame, and three strategies are generally used for the application of navigation surgery to the mandible. This article reports the application of a novel open position splint integrated with a reference frame and registration markers for mandibular navigation surgery as a fourth strategy. Using this custom-made integrated splint, a marker-based pair-point registration procedure was completed easily and non-invasively. Furthermore, the neurovascular canal tract could be easily identified, and the cyst, as well as the surrounding daughter cysts, could be removed with high accuracy. This strategy has potential for widespread clinical application in mandibular navigation surgery.

SHAPE ESTIMATION OF BOWTIE FILTERS BASED ON THE LUMINESCENCE FROM POLYETHYLENE TEREPHTHALATE RESIN BY X-RAY IRRADIATION.

In this study, we devised a novel method estimating the bowtie filter shapes by imaging luminescence from a polyethylene terephthalate (PET) resin with X-ray irradiation in a computed tomography (CT) scanner. The luminescence distribution of the PET resin corresponding to the thickness of bowtie filter was imaged using a charge-coupled device camera. On the assumption that the material of bowtie filter is aluminium (Al), the shape of bowtie filters was estimated from the correlation between Al attenuation curves and the angular-dependent luminance attenuation profiles according to the thickness of bowtie filters. Dose simulations based on the estimated bowtie filter shapes were performed using head and body PMMA phantoms with 16 and 32 cm in diameter. The simulated values of head and body weighted CT dose index (CTDIw) based on bowtie filter shape by the luminescence imaging method agreed within ~9% with the measured values by a dosemeter.

MEASUREMENT OF INTERNAL RADIATION DOSE DISTRIBUTION IN CT EXAMINATIONS USING POLYETHYLENE TEREPHTHALATE RESIN.

This study proposes a new dosimetry method for the estimation of the internal radiation dose distribution of a subject undergoing computed tomography (CT) examinations. In this novel method, dose distribution of a subject by CT scans was estimated based on radiophotoluminance distribution with polyethylene terephthalate (PET) resin which was cut to the average head size of a Japanese 1-year-old child. The difference in dose distribution depending on the type of bowtie filter was visualized by imaging luminance distribution with the PET phantom using a charge-coupled device camera. Dose distribution images simulated from a water phantom of the same size as the PET phantom were compared with the luminance distribution images. The linear correlation was demonstrated between luminance of the PET phantom and the simulated water dose. In comparison with the simulated water doses and the converted water doses from luminance of the PET phantom, the relative differences were within 20%.

[Successful treatment for descending necrotizing mediastinitis; report of a case].

A case of a 55-year-old man with descending necrotizing mediastinitis (DNM) after a tooth removal was reported. Chest computed tomography (CT) showed a fluid collection in the right thorax, in the cervical region and in the mediastinum. The patient underwent cervical drainage and thoracoscopic pleural dissective drainage. The cervical and right anterior thoracic drain was removed on the 6th day and posterior drain was removed on the 8th day after the operation. The patient was discharged on the postoperative day 13, and showed no recurrence.

Three-dimensional finite element model to predict patterns of pterygomaxillary dysjunction during Le Fort I osteotomy.

The aim of this study was to determine whether non-linear three-dimensional finite element analysis (3D-FEA) can be applied to simulate pterygomaxillary dysjunction during Le Fort I osteotomy (LFI) not involving a curved osteotome (LFI-non-COSep), and to predict potential changes in the fracture pattern associated with extending the cutting line. Computed tomography (CT) image data (100 snapshots) after LFI were converted to 3D-CT images. 3D-FEA models were built using preoperative CT matrix data and used to simulate pterygomaxillary dysjunction. The pterygomaxillary dysjunction patterns predicted by the 3D-FEA models of pterygomaxillary dysjunction were classified into three categories and compared to the pterygomaxillary dysjunction patterns observed in the postoperative 3D-CT images. Extension of the cutting line was also simulated using the 3D-FEA models to predict the risk and position of pterygoid process fracture. The rate of agreement between the predicted pterygomaxillary dysjunction patterns and those observed in the postoperative 3D-CT images was 87.0% (κ coefficient 0.79). The predicted incidence of pterygoid process fracture was higher for cutting lines that extended to the pterygomaxillary junction than for conventional cutting lines (odds ratio 4.75; P<0.0001). 3D-FEA can be used to predict pterygomaxillary dysjunction patterns during LFI-non-COSep and provides useful information for selecting safer procedures during LFI-non-COSep.

Prevalence of dental caries and sugar consumption among 6-12-y-old schoolchildren in La Trinidad, Benguet, Philippines.

OBJECTIVE: To determine the prevalence of dental caries and the level of sugar consumption among 6-12-y-old schoolchildren in La Trinidad, Benguet, Philippines. DESIGN: A Cross-sectional study as a baseline survey for a later intervention program. A questionnaire was distributed to obtain information on dental history and total consumption of food with sugar. Caries were diagnosed based on the WHO recommendation. RESULTS: A total of 1200 schoolchildren, aged 6-12 y were included. The prevalence of dental caries in primary dentition was 71.7% and in the permanent dentition, 68.2%. The mean total decayed, extracted due to caries and filled primary teeth (DMFT) and decayed, missing and filled permanent teeth (DMFT) were 4.12 (s.d. 4.03) and 2.40 (s.d. 2.57), respectively. As age increased the mean DMFT increased. Majority (70%) had tooth brushing practices, and less than half (42.5%) had a dental visit only when necessary. Their sugar intake was twice more than the WHO recommendation with a mean daily total intake of 59 g per person. Most common sources of dietary sugar were hard candies (89%), banana cue (84.9%), camote cue (84.9%) and soft drinks (84.4%). No significant correlation was found between sugar intake and dental caries. CONCLUSION: The results indicate that dental caries is highly prevalent and increase with augmented sugar consumption. This maybe due to a widespread neglect of oral health and an increased availability of refined sugary products. Caries rates mirrored those of the developing countries with untreated lesions dominating all ages. The high level of untreated caries in all age groups is a cause for concern.

Hexamer palindromic oligonucleotides with 5'-CG-3' motif(s) induce production of interferon.

We have shown previously that 30-mer oligonucleotides containing hexamer palindromic sequences with 5'-CG-3' motif(s) induce interferon (IFN), activate natural killer (NK) cells, and thus exhibit tumor-regressing activity. The present study showed that a hexamer palindromic oligonucleotide (5'-AACGTT-3') alone induced IFN from mouse spleen cells when added with cationic liposomes. Accordingly, 32 kinds of hexamer palindromic oligonucleotides were tested for their ability to induce IFN in the presence of cationic liposomes. The results show that oligonucleotides with NACGTN and NTCGAN sequences exhibited the strongest activity. ACGCGT and TCGCGA also possessed moderate but significant activity. In contrast, palindromes without CG motif(s) were devoid of the activity. No hexamer oligonucleotides showed the activity when liposomes were absent. A complete palindromic sequence was essential as any single base substitution resulted in diminished activity. Among variety of palindromic oligonucleotides of different sizes with an ACGT sequence at the center, the tetramer oligonucleotide was without activity, whereas the activity of hexamer and longer oligonucleotides was almost equally high. These results strongly suggest that the minimal essential structure required for IFN induction is the hexamer palindromic sequence with CG motif(s).

Novel immunotherapy for peritoneal dissemination of murine colon cancer with macrophage inflammatory protein-1beta mediated by a tumor-specific vector, HVJ cationic liposomes.

A critical issue for cancer treatment is control of metastatic or disseminated tumors. Although immune gene therapy has been considered as a possible strategy for treatment of such tumors, successful results have not yet been obtained. To evoke antitumor immunity more efficiently, macrophage inflammatory protein-1beta (MIP-1beta) was used for gene therapy of colon cancer in mice. Injection of hemagglutinating virus of Japan (HVJ) cationic liposomes-MIP-1beta into subcutaneous tumor masses resulted in local expression of MIP-1beta and local accumulation of CD4(+) T lymphocytes. Few studies of cancer gene therapies have targeted peritoneal dissemination. In a mouse model of peritoneal dissemination of colon tumor, we used a luciferase-based assay to demonstrate that HVJ cationic liposomes had high tumor specificity and were effective vectors for transfer of genes in peritoneal dissemination. When mice were treated by intraperitoneal injection of HVJ cationic liposomes containing the MIP-1beta gene, the survival periods of the MIP-1beta-treated mice were significantly longer than those of control mice. Therefore, this HVJ cationic liposome strategy may serve as a powerful tool against peritoneal disseminated cancer.

Osteocompatibility of platinum-plated titanium assessed in vitro.

Suppression of dissolution is important to increase the biocompatibility of titanium implants. Therefore, the possibility of application of platinum-coated titanium as a biomaterial was explored in in vitro experiments using the MC3T3-E1 osteogenic cell line. The data obtained from long-term cultures indicated that pure platinum or titanium thickly coated with platinum inhibited calcification significantly, suggesting that the platinum ion fails to improve the osteocompatibility of titanium implants.

Inhibitory effect of liposomes containing sulfatide or cholesterol sulfate on syncytium formation induced by bovine immunodeficiency virus-infected cells.

The effect of galactocerebroside 3'-sulfate (sulfatide) or cholesterol sulfate on syncytium formation induced by bovine immunodeficiency virus (BIV)-infected cells was investigated in vitro. Sulfatide was purified from bovine brain and incorporated in liposomes which were composed of egg phosphatidylcholine (PC), cholesterol (Chol), and dipalmitoylphosphatidic acid (DPPA). Either sulfatide- or cholesterol sulfate-containing liposomes effectively prevented syncytium formation induced by BIV-infected cells, but the inhibitory effect of sulfatide alone on syncytium formation was low. On the other hand, neither liposomes containing galactocerebroside nor liposomes composed of egg PC, Chol, and DPPA had any effect on syncytium formation induced by BIV-infected cells. These results suggest that liposomes containing sulfatide or cholesterol sulfate are an efficient agent to inhibit syncytium formation induced by BIV-infected cells, and that sulfate residue might play an important role in the inhibition of syncytium formation.

GM1 gangliosidosis type 3 with severe jaw-closing impairment.

The patient had adult GM1 gangliosidosis (type 3) with severe impairment of mastication caused by dystonia of anterior digastric muscles (jaw-opener) on clenching. This is the first report on jaw dystonia severe enough to cause the masticatory impairment in adult GM1 gangliosidosis. The discordance of closing and opening muscles during mastication might be caused by a basal ganglia lesion in this disease.

Hemifacial spasm caused by vascular compression of the distal portion of the facial nerve. Report of seven cases.

It is generally accepted that hemifacial spasm (HFS) and trigeminal neuralgia are caused by compression of the facial nerve (seventh cranial nerve) or the trigeminal nerve (fifth cranial nerve) at the nerve's root exit (or entry) zone (REZ); thus, neurosurgeons generally perform neurovascular decompression at the REZ. Neurosurgeons tend to ignore vascular compression at distal portions of the seventh cranial nerve, even when found incidentally while performing neurovascular decompression at the REZ of that nerve, because compression of distal portions of the seventh cranial nerve has not been regarded as a cause of HFS. Recently the authors treated seven cases of HFS in which compression of the distal portion of the seventh cranial nerve produced symptoms. The anterior inferior cerebellar artery (AICA) was the offending vessel in five of these cases. Great care must be taken not to stretch the internal auditory arteries during manipulation of the AICA because these small arteries are quite vulnerable to surgical manipulation and the patient may experience hearing loss postoperatively. It must be kept in mind that compression of distal portions of the seventh cranial nerve may be responsible for HFS in cases in which neurovascular compression at the REZ is not confirmed intraoperatively and in cases in which neurovascular decompression at the nerve's REZ does not cure HFS. Surgical procedures for decompression of the distal portion of the seventh cranial nerve as well as decompression at the REZ should be performed when a deep vascular groove is noticed at the distal site of compression of the nerve.

Avidity of antibody and agglutinability of antibody-sensitized latex in latex agglutination test.

This paper describes the avidity of IgG antibody used for preparation of latex sensitized with IgG antibody (IgG-sensitized latex) and the agglutinability of IgG-sensitized latex in slide reversed passive latex agglutination (RPLA). Using immunodiffusion techniques, it was found that anti-canine C-reactive protein (CRP) sera from four rabbits immunized with canine CRP had the same antibody titers. However, the antibodies had different levels of avidity. When lattices were sensitized under the same condition with the IgG antibodies of different avidity levels separated from the above-mentioned antisera using Protein A and canine CRP-Sepharose 4B immunosorbent, these demonstrated different patterns of agglutinability in slide RPLA. The latex sensitized with IgG antibody of higher avidity demonstrated a stronger agglutinability.

Racemization of aspartic acid in human cementum with age.

This study explored the application of the racemization reaction to forensic dental medicine in relation to estimation of age from tooth cementum. Cementum from the cervical two-thirds and the apical one-third of 16 upper incisor teeth gave ratios of D-/L-aspartic acid that correlated highly with actual age, the correlation coefficients being r = 0.993-0.996. For whole cementum from lower central and lateral incisors, first and second premolars (n = 8) the correlation coefficients were r = 0.984-0.997. Incisors gave more reliable results than premolars. The study was extended to compare cementum, enamel and dentine from first premolar teeth of the same individuals. The correlation of the ratio of D-/L-aspartic acids with actual age was highest for dentine (r = 0.992), followed by cementum (r = 0.988) and enamel (r = 0.961). These results indicate that the racemization reaction in cementum proceeds in a constant manner, and confirm that cementum remains stable throughout the individual's life. Accurate estimation of age is thus possible when cementum is subjected to the amino-acid racemization method.

Health effects of fluoride pollution caused by coal burning.

Recently a huge amount of fluoride in coal has been released into indoor environments by the combustion of coal and fluoride pollution seems to be increasing in some rural areas in China. Combustion of coal and coal bricks is the primary source of gaseous and aerosol fluoride and these forms of fluoride can easily enter exposed food products and the human respiratory tract. Major human fluoride exposure was caused by consumption of fluoride contaminated food, such as corn, chilies and potatoes. For each diagnostic syndrome of dental fluorosis, a log-normal distribution was observed on the logarithm of urinary fluoride concentration in students in China. Urinary fluoride content was found to be a primary health indicator of the prevalence of dental fluorosis in the community. In the fluorosis areas, osteosclerosis in skeletal fluorosis patients was observed with a high prevalence. A biochemical marker of bone resorption, urinary deoxypyridinoline content was much higher in residents in China than in residents in Japan. It was suggested that bone resorption was stimulated to a greater extent in residents in China and fluoride may stimulate both bone resorption and bone formation. Renal function especially glomerular filtration rate was very sensitive to fluoride exposure. Inorganic phosphate concentrations in urine were significantly lower in the residents in fluorosis areas in China than in non-fluorosis area in China and Japan. Since airborne fluoride from the combustion of coal pollutes extensively both the living environment and food, it is necessary to reduce fluoride pollution caused by coal burning.