副甲状腺ホルモンの間歇投与がステロイド性骨粗鬆症モデルにおけるオッセオインテグレーションの獲得に及ぼす影響

広島大学(Hiroshima University)博士(歯学)Doctor of Philosophy in Dental Sciencedoctora

Effects of continual intermittent administration of parathyroid hormone on implant stability in the presence of osteoporosis: an in vivo study using resonance frequency analysis in a rabbit model

Objective: This study aimed to evaluate the effects of continual intermittent administration of parathyroid hormone (PTH) on implant stability in the presence of osteoporosis, using rabbit models. Material and Methods: Fifteen female New Zealand white rabbits underwent ovariectomy and were administered glucocorticoids to induce osteoporosis, following which they were divided into three groups. The first group received intermittent subcutaneous PTH for 4 weeks until implant placement (PTH1), while the second and third groups received PTH (PTH2) and saline (control), respectively, for 4 weeks before and after implant placement. After intermittent administration of PTH or saline, titanium implants were inserted into the left femoral epiphyses of all animals, and the implant stability quotient (ISQ) was measured immediately after placement to assess the primary stability and at 2 and 4 weeks after implant placement to assess osseointegration. At 4 weeks after implant placement, histological and histomorphometric evaluations were conducted and the bone area around the implant socket was measured as a ratio of the total bone area to the total tissue area. Results: Regarding primary stability, the ISQ values for the PTH1 and PTH2 groups were significantly higher than those for the control group (

Aortic stiffness is strikingly increased with age ≥50 years in clinically normal individuals and preclinical patients with cardiovascular risk factors: Assessment by the new technique of 2D strain echocardiography

SummaryBackgroundVarious measures of aortic stiffness have been proposed as cardiovascular risk markers, but interest has now shifted to more direct and easier evaluation of aortic function. The present study was conducted to determine the feasibility of measuring aortic stiffness (β) with two-dimensional (2D) strain echocardiography and the impact of age and gender on preclinical atherosclerosis.Methods and resultsThe peak circumferential strain of the abdominal aorta was measured using 2D strain echocardiography, and β was determined in 54 clinically normal individuals and 104 patients with cardiovascular risk factors and no evidence of cardiovascular disease. The β correlated significantly with age in all 158 patients. However, the relationship was nonlinear, and β was markedly greater in patients ≥50 years. In 54 clinically normal individuals, the relationship was comparatively linear. The systolic blood pressure and pulse pressure were significantly greater in patients ≥50 years. There were no significant differences in β and blood pressure parameters between genders.ConclusionsThe β increased dramatically with advanced age (≥50 years), regardless of gender, in clinically healthy and community-based patients with cardiovascular risk factors. The aortic circumferential strain was measured with 2D strain echocardiography which is a new tool that can be used to directly and easily evaluate aortic stiffness

Investigation of Effective Modification Treatments for Titanium Membranes

Titanium membranes are used for guided bone regeneration in implant therapy. However, as a bioinert material, titanium does not have the ability to accelerate bone formation. Various titanium surface treatments to confer bioactivity have been demonstrated; however, there are concerns about the influence of chemical treatments for thin titanium membranes. This study investigated the influence of surface modifications on the structure of titanium membranes. Titanium membranes of 20 μm thickness were treated with acid or alkali solutions, and we evaluated their surface structure, wettability, thickness, and mechanical strength compared to non-treated membranes. Alkali-treated titanium membranes displayed the formation of nanoscale pore structures on their surfaces, enhanced hydrophilicity, and almost same thickness compared with acid-treated membranes. Furthermore, the tensile strength of alkali-treated membranes was comparable to non-treated membranes. These results suggest that alkali treatment is an appropriate surface modification method for titanium membranes

Osseointegration aspects of placed implant in bone reconstruction with newly developed block-type interconnected porous calcium hydroxyapatite

Artificial bone has been employed to reconstruct bone defects. However, only few reports on implant placement after block bone grafting exist. Objectives The purpose of this study was to evaluate the osseointegration of dental implant in bone reconstructions with interconnected porous calcium hydroxyapatite (IP-CHA). Material and Methods The IP-CHA cylinders (D; 4.3 mm, H; 10.0 mm) were placed into bone sockets in each side of the femurs of four male dogs. The IP-CHA on the right side was a 24-week sample. Twelve weeks after placement, a titanium implant was placed into a socket that was prepared in half of the placed IP-CHA cylinder on the right side. On the left side, another IP-CHA cylinder was placed as a 12-week sample. After another 12 weeks, the samples were harvested, and the bone regeneration and bone-implant contact (BIC) ratios were measured. Results New bone formation area was superior in the 24-week IP-CHA compared with the 12-week IP-CHA. BIC was not significantly different between IP-CHA and the parent sites. Osseointegration was detected around the implant in IP-CHA-reconstructed bone. Conclusion Our preliminary results suggest that IP-CHA may be a suitable bone graft material for reconstructing bones that require implant placement

Changes in expression levels of ERCC1, DPYD, and VEGFA mRNA after first-line chemotherapy of metastatic colorectal cancer: results of a multicenter study

Our previous study showed that administering oxaliplatin as first-line chemotherapy increased ERCC1 and DPD levels in liver colorectal cancers (CRCs) metastases. Second, whether the anti-VEGF monoclonal antibody bevacizumab alters tumoral VEGFA levels is unknown. We conducted this multicenter observational study to validate our previous findings on ERCC1 and DPD, and clarify the response of VEGFA expression to bavacizumab administration. 346 CRC patients with liver metastases were enrolled at 22 Japanese institutes. Resected liver metastases were available for 175 patients previously treated with oxaliplatin-based chemotherapy (chemotherapy group) and 171 receiving no previous chemotherapy (non-chemotherapy group). ERCC1, DPYD, and VEGFA mRNA levels were measured by real-time RT-PCR. ERCC1 mRNA expression was significantly higher in the chemotherapy group than in the non-chemotherapy group (P = 0.033), and were significantly correlated (Spearman\u27s correlation coefficient = 0.42; P < 0.0001). VEGFA expression level was higher in patients receiving bevacizumab (n = 51) than in those who did not (n = 251) (P = 0.007). This study confirmed that first-line oxaliplatin-based chemotherapy increases ERCC1 and DPYD expression levels, potentially enhancing chemosensitivity to subsequent therapy. We also found that bevacizumab induces VEGFA expression in tumor cells, suggesting a biologic rationale for extending bevacizumab treatment beyond first progression

Estimation of Obstacle Avoidance in Children with Developmental Disorders and Normal Children

[目的]本研究の目的は,発達障害児の障害物回避の見積もり能力を明らかにすることであった。[方法]対象は5～6歳の発達障害児と健常児,各9名とした。視覚弁別課題として,7.0m離れた位置から異なる高さの2本のバーの高低を比較させた。また,接触回避を見積もる課題として,異なる高さのバーを1本ずつ呈示し,かがみ込むことなしに,身体を接触させずに通り抜けることができるかどうかを回答させた。[結果]視覚弁別課題では発達障害児の正答数は9.22±.63回,健常児は9.78±.42回であり,有意な差は見られなかった。見積もり課題では,発達障害児の正答数は7.78±.67回,健常児は8.56±.73回であり,発達障害児の正答数が有意に少なかった。[結語]発達障害児は身長とバーとの相互関係からバーへの接触回避を見積もる能力が劣っていたために,障害物に接触する頻度が高いのではないかと考えられた。[Purpose] The purpose of this study was to investigate the ability of children with developmental disorders (CDD) to make estimations related to the avoidance of obstacles. [Method] Participants were 9 CDD and 9 healthy children (HC) who had been diagnosed as having attention deficit-hyperactivity disorder or Asperger's syndrome, aged 5-6. As a visual discrimination task, participants compared 2 bars at different heights from a distance of 7.0m. Furthermore, in order to test their estimation of obstacle avoidance, bars of different heights were displayed one by one, and participants were asked to judge whether it would be possible to pass without crouching or bumping into the bars. [Results] CDD and HC performed similarly in the visual discrimination tests. However, CDD fell behind HC in their ability to use body images to estimate the possibility of pass-under movements. [Conclusion] These results suggest that the reason that CDD bump into obstacles lies in the inaccuracy of their own body images. The above results indicate that it is difficult for CDD, in comparison to HC, to make estimations of the possibility of avoiding physical contact with obstacles based on body image

A Study of Physical Contact in Passing-Under Movements : Children with Developmental Disorder Have More Collisions

[目的]本研究の目的は,くぐり動作を用いて,発達障害児と健常児の障害物への身体接触を比較検証することであった。[対象]5～6歳の健常児と発達障害児,各9名を対象とした。[方法]課題は7種類の遊具と高さの異なる6つのバーを交互に設置したコースを通り抜けることであった。障害物との接触回避に関する注意喚起を与えない条件,接触回避を与える条件,そして接触回避および早く移動することを促す条件の3条件を設け,それぞれ1試行ずつ行わせた。[結果]発達障害児は健常児に比べて,条件に関わらず接触頻度が高かった。また,発達障害児は腰部の接触頻度が高かった。[結語]発達障害児の接触の多さは,注意の欠陥が原因ではないと考えられる。また,視覚フィードバックを随時利用して,接触しないようにくぐり動作を行うことが困難な状況において身体接触が多いことから,身体特性情報に基づく行為の見積もりの不正確さが,発達障害児の身体接触の多さの原因であることを示唆した。[Purpose] In this study, we examined physical contact with obstacles by children with and without developmental disorders (DD). [Subjests] Participants were nine children with DD and nine normal children. [Methods] All participants went through a course with seven pieces of playground equipment and six bars at different heights under three conditions: the first trial was with no instruction, the second trial was with an instruction to avoid collision, and the third trial was with an instruction to avoid collision and go through as fast as possible. [Results] The children with DD had more physical contact with the bars than normal children, indicating that attention deficit was not the cause of the increased contact in the children with DD. They also showed a significantly higher number of waist-contacts when compared to the normal children. This suggests that the children with DD had more contact when concurrent visual-feedback could not be used during avoidance movements. [Conclusion] It is possible that incorrect estimation based on body-characteristic information is the cause of the increased contact in the children with DD