Amelogenin enhances the osteogenic differentiation of mesenchymal stem cells derived from bone marrow

Amelogenins are the major constituent of developing extracellular enamel matrix proteins and are understood to have an exclusively epithelial origin. Recent studies have demonstrated that amelogenins can be detected in other tissues, including bone marrow mesenchymal stem cells (MSCs), but the role of amelogenins in MSCs remains unclear. The purpose of this study was to examine the effect of recombinant human full-length amelogenin (rh174) on the osteogenic differentiation of cultured human MSCs. MSCs isolated from human bone marrow were cultured in osteoblastic differentiation medium with 0, 10 or 100 ng/ml rh174. The mRNA levels of bone markers were examined by real-time PCR analysis. Alkaline phosphatase (ALP) activity and calcium concentration were determined. Mineralization was evaluated by alizarin red staining. The mRNA levels of ALP, type I collagen, osteopontin and bone sialoprotein in the MSCs treated with rh174 became significantly higher than those in non-treated controls. Treatment of MSCs with rh174 also enhanced ALP activity and calcium concentration, resulting in enhanced mineralization, as denoted by high intensity of alizarin red staining. In conclusion, the present study showed that rh174 enhances the mineralization accompanied by the upregulation of bone markers in human bone marrow MSCs during osteogenic differentiation, suggesting a certain role of amelogenin in the modulation of osteogenic differentiation of MSCs.

Correlation between genotype and supernumerary tooth formation in cleidocranial dysplasia

INTRODUCTION

Cleidocranial dysplasia (CCD, MIM#119600), for which the responsible gene is RUNX2, is a genetic disorder characterized by hypoplasia or aplasia of the clavicles, patent fontanelles, and a short stature. Supernumerary teeth and delayed eruption and impaction of permanent teeth are frequently associated with CCD. Our previous study reported wide intrafamilial variation in supernumerary tooth formation associated with a mutation in the RUNT-domain of RUNX2, suggesting a low correlation between the genotype and supernumerary tooth formation. To further clarify this point, a more precise evaluation was performed.

DESIGN

Gene mutational analysis of nine Japanese individuals with CCD was performed. Dental and skeletal characteristics were examined based on patient examinations and radiographs.

RESULTS

Four different gene mutations, including one novel mutation in RUNX2 gene (NM_001024630), were identified. Among them, four individuals had the R225Q mutation, three siblings had the P224S mutation, and the other two individuals had different frame-shift mutations. Wide variations in supernumerary tooth formation were observed in individuals with identical gene mutations, and discordance was seen between monozygotic twins. Asymmetric supernumerary tooth formation was noted in five out of the nine individuals.

CONCLUSION

Individuals with identical gene mutations showed a wide variation in the supernumerary tooth formation. Not only the genotype but also environmental factors and a complex system including epigenetics and copy number variation might regulate supernumerary tooth formation in CCD.

Radiographic findings and prognosis of simple bone cysts of the jaws

OBJECTIVE

The aim was to evaluate the possibility of radiographic prediction of the prognosis of simple bone cysts (SBCs) of the jaws.

METHODS

The relationship between the radiographic findings and treatment outcome (healing or recurrence) was investigated in 31 cases treated in the authors' hospital and 108 published cases.

RESULTS

In 17 of our 31 cases, the lesions had radiographic findings of a preserved lamina dura adjacent to the lesion, with a smooth margin, and no or smooth bone expansion, and all of them healed after surgery. In the other 14 cases, there was resorption of the lamina dura, a scalloped margin, nodular bone expansion, root resorption, a sclerotic mass or multiple cavities, and nine cases of recurrence. Although there was incomplete information in the published case studies, similar results were noted.

CONCLUSIONS

It was concluded that there was a relationship between the radiographic features of the lesions and prognosis. Radiographic examination should be used not only for discovering and diagnosing the lesions, but also for predicting possible prognosis.

Effects of mechanical stimuli on the synthesis of superficial zone protein in chondrocytes

Superficial zone protein (SZP) has been demonstrated to contribute to the boundary lubrication in synovial joints. This study was designed to clarify the modulation of SZP expression by mechanical stress in articular chondrocytes. Cyclic tensile strains of 7 and 21% cell elongation were applied to cultured chondrocytes obtained from porcine mandibular condylar cartilage. The mRNA levels of SZP, IL-1 beta, and TGF-beta1 were examined by a quantitative real-time PCR analysis. Protein level of SZP was examined by Western blotting. The SZP mRNA level was significantly upregulated after 12, 24, and 48 h by 7% elongation. Although SZP mRNA level was upregulated by 21% elongation after 12 h, it decreased to a lower level than the control after 48 h. The TGF-beta1 mRNA level exhibited an almost similar change to SZP. The IL-1 beta mRNA level was not changed markedly by 7% elongation. However, the IL-1 beta mRNA level was significantly increased by a 12-h application of 21% elongation. Western blot analysis revealed that the SZP expression was increased by 7% elongation, but decreased remarkably by 21% elongation. It is suggested from these findings that the SZP expression level in the chondrocytes is enhanced by optimal mechanical stimuli, but inhibited by excessive loading partly affected by TGF-beta1 and IL-1 beta, leading to the deterioration of joint lubrication.

Stress analysis in the mandibular condyle during prolonged clenching: a theoretical approach with the finite element method

Parafunctional habits, such as bruxism and prolonged clenching, have been associated with functional overloading in the temporomandibular joint (TMJ), which may result in internal derangement and osteoarthrosis of the TMJ. In this study, the distributions of stress on the mandibular condylar surface during prolonged clenching were examined with TMJ mathematical models. Finite element models were developed on the basis of magnetic resonance images from two subjects with or without anterior disc displacement of the TMJ. Masticatory muscle forces were used as a loading condition for stress analysis during a 10 min clenching. In the asymptomatic model, the stress values in the anterior area (0.100 MPa) and lateral area (0.074 MPa) were relatively high among the five areas at 10 min. In the middle and posterior areas, stress relaxation occurred during the first 2 min. In contrast, the stress value in the lateral area was markedly lower (0.020 MPa) than in other areas in the symptomatic model at 10 min. The largest stress (0.050 MPa) was located in the posterior area. All except the anterior area revealed an increase in stress during the first 2 min. The present result indicates that the displacement of the disc could affect the stress distribution on the condylar articular surface during prolonged clenching, especially in the posterior area, probably leading to the cartilage breakdown on the condylar articular surface.

Optimal patient selection for CPT-11 chemotherapy in colorectal cancer: Quantitative prediction of tumor response and overall survival using expression data of novel marker genes

e14529

Background: Unlike the toxicity, none of the critical prediction markers of CPT-11 efficacy has been validated to date. With a hypothesis that expression analysis of a set of the key drug sensitivity genes could allow us to predict the therapeutic response, we identified potent marker genes for CPT-11 in in vitro, conducted this prospective study attempting to develop a prediction formula of efficacy using the expression data (2006 ASCO, 2006 ESMO), and demonstrated the latest prediction formula of the best tumor response (BTR), time to treatment failure (TTP), and the overall survival after CPT-11 chemotherapy (OS). Methods: Seven genes identified as possible marker genes for CPT-11 (SN-38)- AMD1, CTSC, EIF1AX, FLJ13089 , DDX54, PTPN2, and TBX3-, and 5 other possible marker genes (ABCG2, CYP3A4, MGMT, POR, and TOP2A) that had already been known as drug sensitivity determinants and selected by our in vitro screening process, were studied. CPT-11 was intravenously administered on Days 1, 8, and 15, every 4 weeks in chemo-naive patients with stage IV colorectal cancer after palliative operation. Tumor samples were collected at surgery and tumor response was evaluated by RECIST. Results: All of the 44 enrolled patients were assessable for BTR (% of initial tumor size), TTP (day), and OS (day) in the clinical study, and we successfully developed the best linear model for each, which converted the quantified expression data of the 7 selected genes into objective BTR, TTP, and OS. We used 20, 16, and 15 tumor specimens and constructed potent prediction formulae for BTR (r=0.9420), TTP (r=0.7103), and OS (r=0.8406), respectively. Utility-confirmation analyses using another 16, 10, 13 clinical samples appeared to show that the formulae could predict BTR (r=0.6491, p=0.007) and OS (r=0.7947, p=0.011). We also fixed the best linear models using 5 other known marker genes, but they had less advantage in prediction. Conclusions: Despite limited data, our developed formulae using the 7 novel genes would provide advantages in prediction of individual response to CPT-11. Based on the positive results of this study, we have initiated a large scale validation study of the formula.

[Table: see text]

Randomized phase II/III study of docetaxel/S-1 (DS-1) versus CDDP/5FU (FUP) in advanced or recurrent gastric cancer: Updated phase II results

4595

Background: Our previous single arm phase II trial demonstrated that the combination of DS-1 was one of the most powerful candidates to become a standard regimen for metastatic gastric cancer (K. Yoshida, et al: Clin Cancer Res 2006). This trial evaluated DS-1 and FUP in advanced or recurrent gastric cancer, and the primary objective of the phase II part was to evaluate activity and safety of the 2 regimens. Methods: Patients with advanced or recurrent gastric cancer, who had not received any chemotherapy except one regimen (not including taxanes), were eligible for this trial. Patients were randomized to either: DS-1, intravenous administration of 40 mg/m2 docetaxel on Day1 and oral administration of 80–120 mg/m2/day S-1 on Days 1 to 14 every 3 weeks, or FUP, intravenous continuous administration of 800 mg/m2/day 5-FU on Day 1 to 5 and intravenous administration of 80 mg/m2/day CDDP on Day 2 every 4 weeks. Results: Between June 2005 and August 2008, forty-nine of 54 patients (ECOG PS 0–2) were randomized to DS-1 (n=24) or FUP (n=25). Response rates (CR+PR) assessed by RECIST were 88.3% (CI;62.6–95.3) vs 52.0% (CI; 31.3–72.2, P=0.032), median times to treatment failure (TTF) were 122 days (CI; 75.2–168.8) vs 85 days (CI;67.9–102.1, P=0.003), median progression free survivals (PFS) were 198 days (CI;117.8–278.4) vs 105 days (CI;90.3–119.7, P=0.066). Median overall survival times (MSTs) were 369 days (CI; 359.6–378.4) vs 371 days (CI; 297.2- 444.8, P=0.281), but as of today, 14 pts (8 in DS-1 and 6 in FUP) are still alive. Grade 3/4 adverse events assessed by CTCAE v3.0 occurring in ≥20% patients, were neutropenia (58.3% vs 28.0%), nausea (4.2% vs 20.0%), leucopenia (33.0% vs 4.0%), fatigue (0% vs 20.0%) and anorexia (8.3% vs 32.0%). All treatment-related adverse events were resolved and no toxic death was reported. Conclusions: DS-1 significantly improved the RR and TTF in advanced or recurrent gastric cancer patients. To clarify the survival benefit, a phase III continuation of the study is in preparation.

No significant financial relationships to disclose.

The reliability of computed tomography (CT) values and dimensional measurements of the oropharyngeal region using cone beam CT: comparison with multidetector CT

OBJECTIVES

To evaluate the reliability of cone beam CT (CBCT) values and dimensional measurements of oropharyngeal air spaces as compared with those of multidetector row CT (MDCT).

METHODS

A soft tissue equivalent phantom with different sized holes was used. The phantom was scanned using CBCT and MDCT. In addition, a volunteer was examined using both methods for clinical comparison. The CT data were retrieved to a personal computer and treated using image processing software for three-dimensional rendering and dimensional measurements. The CT values of air, water and soft tissues were measured experimentally and the CT values of air, fat and muscle were measured in a clinical case. The diameter of each hole drilled in the phantom was measured on CBCT and MDCT images using the software tool and digimatic callipers.

RESULTS

The CBCT values were quite different from the Hounsfield units obtained with a typical MDCT system. The standard deviations were almost ten times larger with CBCT. In vivo assessment showed that the CBCT values for fat had a wide range that partially overlapped the values for muscle. The measurement of distances greater than 4 mm was consistent for all methods. The difference for holes was less than 0.2 mm.

CONCLUSIONS

The phantom study showed that CBCT provides limited quantitative CT values for each pixel on sliced images for differentiating air, water and soft tissues. However, the measurement of air spaces with CBCT was quite accurate.

Observer performance in diagnosing osteoporosis by dental panoramic radiographs: results from the osteoporosis screening project in dentistry (OSPD)

Mandibular cortical erosion detected on dental panoramic radiographs (DPRs) may be useful for identifying women with osteoporosis, but little is known about the variation in diagnostic efficacy of observers worldwide. The purpose of this study was to measure the accuracy in identifying women at risk for osteoporosis in a worldwide group of observers using DPRs. We constructed a website that included background information about osteoporosis screening and instructions regarding the interpretation of mandibular cortical erosion. DPRs of 100 Japanese postmenopausal women aged 50 years or older who had completed skeletal bone mineral measurements by dual energy X-ray absorptiometry were digitized at 300 dpi. These were displayed on the website and used for the evaluation of diagnostic efficacy. Sixty observers aged 25 to 66 years recruited from 16 countries participated in this study. These observers classified cortical erosion into one of three groups (none, mild to moderate, and severe) on the website via the Internet, twice with an approximately 2-week interval. The diagnostic efficacy of the Osteoporosis Self-Assessment Tool (OST), a simple clinical decision rule based on age and weight, was also calculated and compared with that of cortical erosion. The overall mean sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the 60 observers in identifying women with osteoporosis by cortical erosion on DPRs were 82.5, 46.2, 46.7, and 84.0%, respectively. Those same values by the OST index were 82.9, 43.1, 43.9, and 82.4%, respectively. The intra-observer agreement in classifying cortical erosion on DPRs was sufficient (weighted kappa values>0.6) in 36 (60%) observers. This was significantly increased in observers who specialized in oral radiology (P<0.05). In the 36 observers with sufficient intra-observer agreement, the overall mean sensitivity, specificity, PPV, and NPV in identifying women with osteoporosis by any cortical erosion were 83.5, 48.7, 48.3, and 85.7%, respectively. The mean PPV and NPV were significantly higher in the 36 observers with sufficient intra-observer agreement than in the 24 observers with insufficient intra-observer agreement. Our results reconfirm the efficacy of cortical erosion findings in identifying postmenopausal women at risk for osteoporosis, among observers with sufficient intra-observer agreement. Information gathered from radiographic examination is at least as useful as that gathered from the OST index.

Positional changes of oropharyngeal structures due to gravity in the upright and supine positions

OBJECTIVES

To compare the responses of oropharyngeal structures to gravity while sitting upright or lying down in a supine position.

METHODS

Seven subjects were evaluated by cone beam CT (CBCT) while in the upright position and by a four-row multidetector helical CT (MDCT) while in the supine position. All of the voxel sizes were adjusted to be 0.3x0.3x0.3 mm3 in the x-y-z axis. The posterior nasal spine, basion and fourth cervical bone were used as references to measure positional changes in the oropharyngeal structures between the upright and supine positions. The smallest areas in the oropharynx were also evaluated.

RESULTS

The soft palate, epiglottis and entrance of the oesophagus moved caudally with the positional change from supine to sitting upright, and moved posteriorly when the position changed from an upright to a supine position. The hyoid bone moved caudally but not posteriorly in response to the same positional changes. The width and length of the smallest area present in the oropharynx was larger in the upright position than in the supine position.

CONCLUSIONS

Gravity can produce movements in oropharyngeal structures in response to postural changes between sitting upright and lying in the supine position.

Reduced amelogenin-MMP20 interactions in amelogenesis imperfecta

Amelogenin with a proline 41 to threonine mutation (P41T) is hydrolyzed at a lower rate by matrix metalloproteinase 20 (MMP20), resulting in an inherited tooth enamel defect, amelogenesis imperfecta (AI). The aim of this study was to elucidate the effect of P41T on the interactions between amelogenin and MMP20, which may contribute to the formation of this type of AI. The interactions of a recombinant wild-type human amelogenin and its P41T mutant with recombinant human MMP20 were compared by substrate competition assay, pull-down assay, and surface plasmon resonance (SPR). The results showed that the binding of the P41T mutant amelogenin for MMP20 was significantly lower than that of wild-type amelogenin. Our study supports a model in which the P41T mutation reduces the interactions between amelogenin and MMP20, leading to decreased degradation of amelogenin by MMP20, and resulting in AI.

Human mismatch repair gene, MLH1, is transcriptionally repressed by the hypoxia-inducible transcription factors, DEC1 and DEC2

Tumor hypoxia has been reported to cause a functional loss in DNA mismatch repair (MMR) system as a result of downregulation of MMR genes, although the precise molecular mechanisms remain unclear. In this study, we focused on the downregulation of a key MMR gene, MLH1, and demonstrated that hypoxia-inducible transcription repressors, differentiated embryo chondrocytes (DEC1 and 2), participated in its transcriptional regulation via their bindings to E-box-like motif(s) in MLH1 promoter region. In all cancer cell lines examined, hypoxia increased expression of DEC1 and 2, known as hypoxia-inducible genes, but decreased MLH1 expression in an exposure time-dependent manner at both the mRNA and protein levels. Co-transfection reporter assay revealed that DEC1 and, to greater extent, DEC2 as well as hypoxia-repressed MLH1 promoter activity. We further found that the action was remarkably inhibited by trichostatin A, and identified a possible DEC-response element in the MLH1 promoter. In vitro electrophoretic gel mobility shift and chromatin immunoprecipitation assays demonstrated that DEC1 or 2 directly bounds to the suggested element, and transient transfection assay revealed that overexpression of DEC2 repressed endogenous MLH1 expression in the cells. Hypoxia-induced DEC may impair MMR function through repression of MLH1 expression, possibly via the histone deacethylase-mediated mechanism in cancer cells.

Effects of fluoride on the interactions between amelogenin and apatite crystals

Fluorosed enamel is more porous and less mineralized, possibly related to altered amelogenin-modulated crystal growth. The purpose of this study was to examine the role of fluoride in interactions between amelogenin and apatite crystals. Recombinant human amelogenin (rh174) was bound to carbonated hydroxyapatite containing various amounts of fluoride, and analyzed by protein assay, SDS PAGE, and AFM. Interactions between rh174 and fluoride were assayed by isothermal titration calorimetry (ITC). The initial binding rate of rh174, as well as total amount of rh174 bound to fluoride-containing carbonated hydroxyapatite, was greater than that in the control carbonated hydroxyapatite. Fluoride in solution at physiologic (5.3 micromolar, or 0.1 ppm) concentrations showed no significant effect on binding, but higher fluoride levels significantly decreased protein binding. ITC showed no interactions between fluoride and rh174. These results suggest that fluoride incorporation into the crystal lattice alters the crystal surface to enhance amelogenin binding, with no direct interactions between fluoride and amelogenin.

The effects of the sympathetic nerves on lumbar radicular pain

A rat model of lumbar root constriction with an additional sympathectomy in some animals was used to assess whether the sympathetic nerves influenced radicular pain. Behavioural tests were undertaken before and after the operation.

On the 28th post-operative day, both dorsal root ganglia and the spinal roots of L4 and L5 were removed, frozen and sectioned on a cryostat (8 μm to 10 μm). Immunostaining was then performed with antibodies to tyrosine hydroxylase (TH) according to the Avidin Biotin Complex method. In order to quantify the presence of sympathetic nerve fibres, we counted TH-immunoreactive fibres in the dorsal root ganglia using a light microscope equipped with a micrometer graticule (10 x 10 squares, 500 mm x 500 mm). We counted the squares of the graticule which contained TH-immunoreactive fibres for each of five randomly-selected sections of the dorsal root ganglia.

The root constriction group showed mechanical allodynia and thermal hyperalgesia. In this group, TH-immunoreactive fibres were abundant in the ipsilateral dorsal root ganglia at L5 and L4 compared with the opposite side. In the sympathectomy group, mechanical hypersensitivity was attenuated significantly.

We consider that the sympathetic nervous system plays an important role in the generation of radicular pain.

Risk of vertebral osteoporosis in post-menopausal women with alterations of the mandible

BACKGROUND

Previous studies have suggested that a thin or eroded cortex of the mandible detected on dental panoramic radiographs is associated with low vertebral bone mineral density (BMD) or osteoporosis. However, those studies did not estimate the multivariate-adjusted risk for low vertebral BMD or osteoporosis associated with alterations of the mandible.

METHODS

BMD of the lumbar vertebrae (L2-L4) was compared among quartiles of cortical width and among three cortical shape categories in 450 post-menopausal women (mean age, 57.2 years), adjusted for potential confounders. The odds ratios for low BMD or osteoporosis according to cortical width and shape were also calculated.

RESULTS

Significant associations were found between cortical width and shape, and vertebral BMD. The odds ratios for low vertebral BMD associated with the second, third and lowermost quartiles of cortical width were 1.71 (95% confidence interval (CI), 0.96-3.05), 2.30 (95% CI, 1.29-4.11) and 5.43 (95% CI, 2.16-10.71), respectively, compared with the uppermost quartile. The odds ratios for osteoporosis according to cortical width category were similar to those for low BMD. The odds ratios for low BMD associated with mildly to moderately and severely eroded cortices were 3.85 (95% CI, 2.37-6.25) and 7.84 (95% CI, 2.57-23.90), respectively, compared with normal cortex. The odds ratios for osteoporosis associated with mildly to moderately and severely eroded cortices were 4.73 (95% CI, 2.54-8.80) and 14.73 (95% CI, 6.14-35.47), respectively.

CONCLUSIONS

Post-menopausal women with alterations of the mandible may have an increased risk for low vertebral BMD or osteoporosis.

Identification of post-menopausal women at risk of osteoporosis by trained general dental practitioners using panoramic radiographs

BACKGROUND

An eroded inferior cortex of the mandible on panoramic radiographs may be useful for identifying post-menopausal women with low bone mineral density (BMD), or osteoporosis. The purpose of this study was to assess whether trained general dental practitioners (GDPs) can identify post-menopausal women with undetected low skeletal BMD as well as spinal fractures by panoramic radiographs in their clinics.

METHODS

Out of 455 women aged 50 years and older who visited the dental clinics of 22 trained GDPs and had panoramic radiographic assessment for the examination of dental diseases between June and December 2004, 168 post-menopausal women were diagnosed as having low skeletal BMD based on cortical erosion findings. Of these women, 39 women aged 50-84 years (mean age (SD, standard deviation), 64.8 (7.4) years) with no previous diagnosis of osteoporosis participated in this study. BMD at the lumbar spine and femoral neck was measured using dual energy X-ray absorptiometry (DXA). Spine fractures were assessed on lateral radiographs obtained at the time of the DXA assessment.

RESULTS

Two women (5.1%) had normal BMD (BMD T-score>-1.0), 21 women (53.9%) had osteopenia (BMD T-score of -2.5 to -1.0) and 16 women (41.0%) had osteoporosis (BMD T-score<-2.5). Eight women (20.5%) had fractures at the thoracic spine, lumbar spine, or both.

CONCLUSIONS

Our results suggest that a high percentage of post-menopausal women with undetected low skeletal BMD as well as spinal fractures may be identified based on trained GDPs' analyses of their panoramic radiographs.

Absence of chlamydial infection in Japanese patients with orbital adnexal MALT lymphoma

18523

Background: The extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is a distinct B-cell lymphoma that develops in extranodal sites and usually has an indolent clinical course as a localized disease. Recent clinicopathological studies suggest a strong relation between MALT lymphoma and inflammatory diseases of the epithelium such as autoimmune diseases and infections (Sjogren’s syndrome, Hashimoto’s thyroiditis, Helicobacter pylori infection, and etc.), because chronic antigen stimulation has been causally linked to the development of B-cells lymphoproliferative diseases. MALT lymphoma grows in extranodal lymphoid tissue and exists in epithelium tissues, and it is often difficult to distinguish malignant lymphoid tissue from benign inflammation. This is one cause since recent positive or negative correlations between ocular adnexal MALT lymphomas and chlamydial infections have been reported from different researchers, indicate several possible explanations. Methods: Twenty-three cases of ocular adnexal MALT lymphoma in southern regions of Japan, whose monoclonality was confirmed by immunoglobulin heavy chain gene rearrangement and/or cell surface antigens, were analyzed for evidence of several causative factors using ELISA analysis to detect antibodies and Southern blot analysis followed by specific PCR gene amplification. Results: Our series of patients did not show any serological relations to Epstein-Barr virus, Hepatitis C virus, and Chlamydophila psittaci. Two cases had positive serum antibodies for autoimmunity, and another two cases had positive antibodies against Chlamydia trachomatis. None of our cases showed the presence of chlamydial 16S rRNA and 16S-23S spacer rRNA genes (C. psittac, C trachomatis, C. pneumoniae, and C. felis) after Southern blot analysis followed by PCR amplification. Conclusions: Inflammatory agents are still unknown in our series of orbital adnexal MALT lymphomas, and some types of chlamydial infections are not associated with orbital adnexal MALT lymphoma in southern regions of Japan.

No significant financial relationships to disclose.

Pharmacogenomic (PG) analysis for prediction of individual response to paclitaxel in 5-FU-refractory metastatic gastric cancer: Prediction formula of tumor response using novel marker genes and genotypes associated with the toxicity

2538

Background: Taxanes offer hope for improving outcomes of metastatic gastric cancer patients including 5-FU failure cases, but the response remarkably varies among patients. We conducted this prospective PG study for paclitaxel monotherapy to develop a prediction formula of efficacy and to identify potent genetic markers of toxicity. Methods: Paclitaxel was intravenously given on Days 1, 8, and 15, every 4 weeks in 5-FU failure metastatic gastric cancer patients with typical eligibility criteria. Tumor and blood samples were collected before the initial paclitaxel administration for PG. PK analysis was done on day 1 of cycle 1. Tumor response and toxicity were evaluated by RECIST and CTCAE, respectively. Results: Forty-nine pts were enrolled, and up to date, 48 and 44 pts have been determined for worst toxicity and best tumor response, respectively. Observed response rate was 27.3% (12/44), and common grade 3/4 toxicities were neutropenia (31.3%) and leucopenia (20.8%). PG analysis demonstrated that CYP2C8*1C (w/v=27, v/v=5) and CYP2C8 -411T>C (w/v=24, v/v=10) were weakly associated with grade 3/4 leucopenia (p=0.087 and 0.092), and CYP2C8 IVS7+49T> A (w/v=9, v/v=6) might correlate with grade 3/4 anemia (p=0.039), although none of them correlated with any PK parameter. We identified 4 novel potent marker genes (SEPT5, MARN2, PER3, and PISA3) for paclitaxel efficacy in vitro through microarray expression analysis, and then successfully developed the best linear models, which converted the quantified expression data into objective clinical response, in terms of best tumor response (r=0.985, AICS=-5.269) and overall survival (r=0.980, AICS=6.953), using 15 and 13 data sets of gene expression and clinical response, respectively. At present, utility-confirmation analyses using other clinical samples appeared to show that the formulae could accurately predict tumor response. Conclusions: Polygenetic strategies using several known polymorphisms for toxicity and a prediction formula using 4 novel genes for efficacy would be of predictive value for individual response to paclitaxel.

No significant financial relationships to disclose.

Expression of MMP-13 in osteoblast cells and rat tibia after exposure to gamma rays or accelerated carbon ions

In past research, we found that carbon ion irradiation increased bone volume in rats, and a significant amount of cartilage remained inside the carbon ion-irradiated trabeculae. The amounts of matrix metalloproteinase 13 (MMP-13) mRNA in osteoblast-like MC3T3-E1 cells tended to decrease after carbon ion irradiation. The level of MMP-13 mRNA in non-irradiated cells was stable during the experimental period, but in gamma ray-irradiated cells it tended to increase. When localization of MMP-13 in locally irradiated experimental rats was investigated, it was found in the marginal trabeculae in both non-irradiated and gamma ray-irradiated animals. MMP-13 was detected in osteoid and neogenetic bone in the trabeculae surface. The trabeculae in carbon ion-irradiated bone remained cartilaginous. Carbon ion-irradiated rats exhibited weak expression of MMP-13 around the cartilage inside the trabeculae. We conclude that carbon ion irradiation reduced expression of MMP-13, thus suppressing both chondrocyte maturation and cartilage resorption. Increases in hyperplasia of the bone trabeculae and of bone volume were caused by ongoing bone addition and calcification in the absence of sufficient cartilage resorption.

A comparative study of simple bone cysts of the jaw and extracranial bones

OBJECTIVES

To improve the interpretation of simple bone cyst (SBC) lesions of the jaw.

METHODS

A comparative study of SBC lesions of the jaw and extracranial bones was performed through a literature survey.

RESULTS

In extracranial SBC, the cavities were always filled with fluid, and a high recurrence rate was shown through extensive research. Aneurysmal bone cyst (ABC) was included in the differential diagnosis owing to some clinicopathologic similarities. Fluid, gas and blood were found in the cavity in jawbone SBC, and recurrence was believed to be rare. Differential diagnosis was rarely discussed in the literature.

CONCLUSIONS

Based on reports, the cavity did not normally contain gas because no air-fluid level was observed on panoramic radiographs and no density/intensity area indicating gas was seen on CT or MRI. A blood-filled cavity should be examined carefully, and the possibility of an ABC should be considered. The recurrence rate needs to be re-estimated because an extensive survey has not been performed to clarify the treatment outcomes of jawbone SBC.

Diagnostic efficacy of alveolar bone loss of the mandible for identifying postmenopausal women with femoral osteoporosis

OBJECTIVES

Mandibular cortical width (MCW) detected on panoramic radiographs may be useful for identifying postmenopausal women with osteoporosis. There is little known regarding whether alveolar bone loss (ABL) of the mandible detected on panoramic radiographs is a potentially accurate screening tool for osteoporosis in comparison with MCW. The purpose of this study was to evaluate whether ABL of the mandible on panoramic radiographs is useful for identifying femoral osteoporosis in postmenopausal women in comparison with MCW.

METHODS

Three hundred and fifty-four Japanese postmenopausal women (mean age+/-SD, 56.8+/-7.7 years) were recruited for this study. Femoral BMD was measured by dual energy X-ray absorptiometry. Panoramic radiographs were obtained to estimate ABL of the mandible and MCW.

RESULTS

A multiple regression analysis revealed that femoral BMD was significantly associated with MCW (P<0.001), weight (P<0.001), age (P<0.001) and ABL of the mandible (P=0.029; adjusted r(2)=0.380). The area under the ROC curve (AUC) for identifying femoral osteoporosis was 0.609 [95% confidence interval (CI), 0.523-0.696] for ABL of the mandible and 0.779 (95% CI, 0.713-0.844) for MCW, respectively. AUC for ABL of the mandible indicated less accuracy.

CONCLUSIONS

Our results suggest that ABL of the mandible on panoramic radiographs may not be useful for identifying postmenopausal women with femoral osteoporosis in comparison with MCW.

Diagnostic performance of general dental practitioners after lecture in identifying post-menopausal women with low bone mineral density by panoramic radiographs

OBJECTIVES

Mandibular cortical erosion detected on panoramic radiographs may be useful for identifying post-menopausal women with low skeletal bone mineral density (BMD). The purposes of this study were to calculate the diagnostic performance of general dental practitioners (GDPs) who attended a lecture on identifying post-menopausal women with low BMD from findings on panoramic radiographs and to evaluate the influence of GDPs' age on diagnostic performance.

METHODS

After a 1 h lecture, 111 GDPs were asked to classify the mandibular cortex (normal or eroded) on panoramic radiographs obtained from 100 post-menopausal women who have had skeletal BMD assessment. Low BMD was defined as a BMD T score of -1.0 or less. Diagnostic performance was analysed by comparing two groups classified by mandibular cortex (women with normal cortex and women with any eroded cortex) with those classified by BMD (women with normal BMD and women with low BMD).

RESULTS

The mean sensitivity, specificity, positive predictive value, negative predictive value, accuracy and likelihood ratio for a positive risk result were 73.0% (95% confidence interval [CI]; 71.3 to 74.7%), 49.0% (95% CI; 46.4 to 51.5%), 66.9% (95% CI; 66.0 to 67.8%), 57.0% (95% CI; 55.8 to 58.2%), 62.9% (95% CI; 62.1 to 63.7%) and 1.51 (95% CI; 1.44 to 1.58), respectively. GDPs' age did not influence diagnostic performance.

CONCLUSIONS

Our results suggest that 73.0% of women who had low skeletal BMD can be identified by GDPs after a lecture on the use of panoramic radiographs as an aid in diagnosing low BMD; however, the diagnostic performance may not be influenced by GDPs' age.