Root canal treatment with high-frequency waves in rats

The purpose of this study was to develop a high-frequency wave therapy model in rats and to investigate the influence of high-frequency waves on root canal treatment, which may provide a novel strategy for treating apical periodontitis. Root canal treatments with and without high-frequency wave irradiation were performed on the mandibular first molars of 10-week-old male Wistar rats. The mesial roots were evaluated radiologically, bacteriologically, and immunohistochemically. At 3 weeks after root canal treatment, lesion volume had decreased significantly more in the irradiated group than in the non-irradiated group, indicating successful development of the high-frequency therapy model. The use of high-frequency waves provided no additional bactericidal effect after root canal treatment. However, high-frequency wave irradiation was found to promote healing of periapical lesions on the host side through increased expression of fibroblast growth factor 2 and transforming growth factor-β1 and could therefore be useful as an adjuvant nonsurgical treatment for apical periodontitis

Assessment of the functional efficacy of root canal treatment with high-frequency waves in rats

The purpose of this study was to develop a high-frequency wave therapy model in rats and to investigate the influence of high-frequency waves on root canal treatment, which may provide a novel strategy for treating apical periodontitis. Root canal treatments with and without high-frequency wave irradiation were performed on the mandibular first molars of 10-week-old male Wistar rats. The mesial roots were evaluated radiologically, bacteriologically, and immunohistochemically. At 3 weeks after root canal treatment, lesion volume had decreased significantly more in the irradiated group than in the non-irradiated group, indicating successful development of the high-frequency therapy model. The use of high-frequency waves provided no additional bactericidal effect after root canal treatment. However, high-frequency wave irradiation was found to promote healing of periapical lesions on the host side through increased expression of fibroblast growth factor 2 and transforming growth factor-β1 and could therefore be useful as an adjuvant nonsurgical treatment for apical periodontitis.Assessment of the functional efficacy of root canal treatment with high-frequency waves in rats. Saori Matsui, et al. PLOS ONE. 2020.9(29) doi.org/10.1371/journal.pone.023966

リン脂質過酸化物の生物有機化学的合成

Chemoenzymatic synthesis of 1-stearoyl-2-hydropeoxyacyl-sn-glycerophospholipids including phosphatidylcholine (PC-OOH), phosphatidic acid (PA-OOH), phosphatidylethanolamine (PE-OOH), phosphatidylglycerol (PG-OOH) and phosphatidylserine (PS-OOH). The hydroperoxy acyl moieties were prepared via hydroperoxidation of linoleic, dihomo-γ-linolenic and arachidonic acids by soybean, potate lipoxygenase or autoxidation. Their hydroperoxy group was protected as a dimethylperacetal before condensation with lysophosphatidylcholine. Optically active lysophosphatidylcholine was prepared via short pathway involving lipase-catalyzed direct enantioselective stearoylation of 2-O-benzylglycerol and choline phosphate synthesis. Peroxy fatty acids and lysophosphatidylcholine thus obtained were condensed using dicyclohexylcarbodiimide in chloroform. Removing the peracetal group in the product and purification by reverse-phase chromatography afforded the desired PC-OOH’s. PA-OOH, PG-OOH, PE-OOH and PS-OOH were obtained by phospholipase-D catalyzed transphosphatidylation from PC-OOH. As a reference compound for biological studies of hydroperoxy phopholipid, PC-OH's were also prepared in which hydroxy unsaturated fatty acyl group was linked to the sn-2 position of the glycerophospholipids.健康正常人の血液などの組織中にはリン脂質過酸化物が極微量で存在し，疾病や老化によってその濃度が顕著に上昇する事が知られている．その事が明らかにされた当初は，極めて複雑な混合物をなす生体脂質中に含まれる不安定な極微量の過酸化脂質を単離・構造決定する事は殆ど不可能と考えられていた．現在もなお，そのような脂質過酸化物を生体組織から純粋に取り出し，構造決定したという報告は無い．従ってそのような分子種の化学的・生理学的性質は不明であったが，脂肪酸過酸化物が毒性を示す事から，リン脂質過酸化物もおそらく毒性を示すだろうと考えられてきた．このような漠然とした推定を科学的に明らかにするためには，化学合成によらざるを得ない．我々はこの未知の合成に取りかかった．しかし，従来の化学的手法のみでは不可能である事も明らかであった．その中で予想された困難の一つは極めて不安定なヒドロペルオキシ基を不飽和脂肪酸のある特定の位置にどのように導入するかという問題と，ヒドロペルオキシ基に影響を与える事なく合成中間体をどのように化学変換するかであった．第一の問題に対する解決策として，不飽和脂肪酸に大豆リポキシゲナーゼを作用させる事で解決する事ができた．植物に広く分布する酵素であるリポキシゲナーゼは植物中でリノール酸に作用して過酸化し，その生成物にヒドロペルオキシドリアーゼという酵素が作用して種々のアルデヒドが精製し，これは植物の青臭みを与える．第二の問題に対しては，リノール酸に導入された不安定なヒドロペルオキシ基をパーアセタールとしての保護する事により解決した．この保護基は，中間体から最終生成物に至るまでの反応条件，例えばDCCによるアシル化反応に対して安定である事が明らかとなった．この二つの問題を解決する事によって，リン脂質過酸化物の一つであるホスファチジルコリン過酸化物を世界に先駆けて成功した．さらにこのホスファチジルコリン過酸化物に微生物由来のホスフォリパーゼDを作用させる事によってホスファチジルエタノールアミン過酸化物，ホスファチジルセリン過酸化物やホスファチジルグリセロール過酸化物の合成にも成功した．また，トリグリセリド過酸化物の合成も可能になった．これらの脂質過酸化物が化学的に実態のあるものとして認識されてから，その生理作用に関する研究が広範に行われている．しかし，生体組織に存在するリン脂質過酸化物の生理学的役割は依然として明らかになっていない．ある種のリン脂質過酸化物が動物の免疫系を活性化するという報告もあり，必ずしも生体に対して悪い作用をするばかりではないようである

Temporal Variation of Radiocarbon Concentration in Airborne Particulate Matter in Tokyo

From the 18th International Radiocarbon Conference held in Wellington, New Zealand, September 1-5, 2003.The temporal radiocarbon variation (in terms of percent Modern Carbon: pMC) of size-fractionated airborne particulate matter (APM) collected in Tokyo between April 2002 and February 2003 was analyzed in order to get an insight into the sources of carbonaceous particles. Results indicated significant biogenic origins (approximately 40 pMC on average). In general, the seasonal and particle size variations in pMC were relatively small, with 2 exceptions: elevated pMC in coarse particles in April and October 2002, and relatively low pMC in the finest particle size fraction collected in August 2002. The former finding could be tentatively attributed to the abundance of coarse particles of biological origins, such as pollen; the latter might be due to an increased fraction of anthropogenic secondary particles.The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

Assessment of the functional efficacy of root canal treatment with high-frequency waves in rats.

The purpose of this study was to develop a high-frequency wave therapy model in rats and to investigate the influence of high-frequency waves on root canal treatment, which may provide a novel strategy for treating apical periodontitis. Root canal treatments with and without high-frequency wave irradiation were performed on the mandibular first molars of 10-week-old male Wistar rats. The mesial roots were evaluated radiologically, bacteriologically, and immunohistochemically. At 3 weeks after root canal treatment, lesion volume had decreased significantly more in the irradiated group than in the non-irradiated group, indicating successful development of the high-frequency therapy model. The use of high-frequency waves provided no additional bactericidal effect after root canal treatment. However, high-frequency wave irradiation was found to promote healing of periapical lesions on the host side through increased expression of fibroblast growth factor 2 and transforming growth factor-β1 and could therefore be useful as an adjuvant nonsurgical treatment for apical periodontitis