Expression of Neurotrophins and Their Receptors Tropomyosin-related kinases (Trk) under Tension-stress during Distraction Osteogenesis

The localization and expression of neurotrophins and their receptors during distraction osteogenesis was investigated in 72 male rat femurs (11 weeks old) to further clarify the concurrence of cellular and molecular events of new bone formation. After osteotomy, a 7-day lag phase was followed by distraction at the rate of 0.25 mm/12 h for 21 days (distraction phase), and a 7-day consolidation phase. The localization of neurotrophins (NGF, BDNF and NT-3) and their receptors tropomyosinrelated kinases (TRKA, TRKB and TRKC) by immunostaining showed positive staining in bone forming cells in each stage, although the presence and staining intensity varied by cell type and phase. The expressions of NGF, BDNF and NT-3 by real-time polymerase chain reaction (real-time PCR) showed that the peak of the mRNA expression of NGF occurred 10 days after distraction. NT-3 increased during bone extension, but decreased when distraction stopped. In contrast, BDNF continued to increase gradually throughout the distraction and consolidation phases. These findings suggest that neurotrophins and their receptors may play different roles in endochondral and intramembranous ossification in distraction osteogenesis. The tension stress caused by distraction may stimulate the expression of neurotrophins and their receptors, and promote osteogenesis

Palatal bone defect mimicking a chronic periapical lesion: a case report emphasizing the importance of the use of a three-dimensional radiographic examination

Lesão periapical crônica é uma das patologias ósseas mais comuns em dentes humanos, e é detectada primariamente por radiografia simples, como a panorâmica ou periapical. Radiografias simples são amplamente utilizadas em odontologia; no entanto, elas são limitadas por questões inerentes à técnica em si, tais como a sobreposição de estruturas anatômicas e a falta de informação sobre a extensão da lesão. Portanto, métodos radiográficos tridimensionais, como a tomografia computadorizada de feixe cônico, são valiosos para avaliar com precisão as lesões periapicais. Dessa forma, este relato clínico descreve um caso em que as características radiográficas de osso levaram a um diagnóstico primário de lesão periapical crônica nos incisivos superiores, no entanto, era um defeito palatino. A radiolucência resultante foi causada pelo defeito palatino sobreposto ao osso maxilar, imitando, assim, uma lesão periapical. Além disso, no mesmo caso, demonstramos uma lesão periapical crônica verdadeira em outra área. Essa lesão apareceu como uma radiolucência sutil na radiografia periapical, mas foi maior que o esperado quando avaliada por tomografia computadorizada de feixe cônico.Chronic periapical lesion is among the most usual bone pathology observed in human teeth, and it is often first detected by plain radiographs, such as panoramic or periapical radiography. Plain radiographs are widely used in dentistry; however, they have limitations inherent to the technique itself, such as anatomic structures overlapping and lack of information on the extension of the lesion. Therefore, three-dimensional radiographic methods, such as cone beam computed tomography are valuable to accurately assess periapical lesions. Thus, this clinical report describes a case in which the bone radiographic features led to a primary diagnosis of chronic periapical lesion in superior incisors, however, it was a defect in the palatal bone. The resulting radiolucency created by the palatal bone defect overlapped the maxillary bone, mimicking a periapical lesion. Additionally, in the same case, we demonstrate a true chronic periapical lesion in another area that presented as a subtle radiolucency in periapical radiography, however, it was larger than expected when evaluated in Cone Beam Computed Tomography

加温後のtsAF8細胞の細胞周期

Thermotolerance in tsAF8 cells develops during incubation at 34℃ after heating at 45℃, while it is suppressed by the following incubation at a non-permissive temperature of 39.7℃ after the same heating. The incubation temperature after heating may affect the cell cycle and consequently thermotolerance. In the present study, a relationship between the thermotolerance and the cell cycle of tsAF8 was investigated. The cell cycle fractions and DNA synthesis were measured by flow cytometry using double staining with propidium iodide and bromodeoxyuridine. When the tsAF8 cells were heated at 45℃ for 20 min, and thereafter incubated at 34℃, bromodeoxyuridine uptake in the S phase cells (DNA synthesis) was recovered to 65.1% 6 h after the heating, and the cells showed gradual accumulation in the G(2)/M phase. When the cells were incubated at 39.7℃ after heating at 45℃ for 20 min, then showed inhibition of thermotolerance development, the DNA synthesis was recovered to 15.1% temporarily 6 h after the heating, but it became 0% after 12 h, and the cells did not remarkably accumulate in any phases of the cell cycle. This inhibition of DNA synthesis at 39.7℃ was considered to be the result of cell survival decreasing by a step-down heating. However, the relationship between the thermotolerance and the cell cycle was not found out in tsAF8 cells, because the cells did not accumulate in any phases of the cell cycle under the inhibitory condition of thermotolerance.tsAF8細胞は45℃の加温後34℃で培養すると温熱耐性が速やかに発現するが,加温後,制限温度である39.7℃で培養すると温熱耐性の発現が抑制される｡加温後の培養温度が細胞周期に影響し,その結果として温熱耐性発現に影響を与えている可能性があることから,今回,Propidium Iodide(PI)とbromodeoxyuridine(BrdU)でtsAF8細胞を二重染色し,フローサイトメトリーによって温熱耐性と細胞周期の関係の有無について調べた｡tsAF8細胞を45℃20分の加温後34℃で培養すると,6時間後にはG(1)期の細胞が減少し,12時間後にはG(2)/M期への蓄積が見られた｡しかし,加温後39.7℃で培養した場合には細胞周期の進行がほとんど見られなかった｡BrdU の取込みは,加温せずに39.7℃で培養した場合には活発に行われ,また,45℃20分加温後34℃で培養した場合には,6時間後にはBrdUの取り込みは65.1%まで回復した｡しかし,温熱耐性発現の抑制が観察される45℃20分加温後39.7℃で培養した場合には,BrdUの取込み量は6時間後に一時的に15.1%に回復するが,12時間後には取込み量はゼロとなった｡BrdUの取り込みが阻害されたのはstep-down heatingの現象による細胞生存率の減少が原因だと考えられたが,温熱耐性発現の抑制が観察される条件下では細胞周期の特定の時期への集積がなかったことから,温熱耐性と細胞周期との関係はtsAF8細胞においては見い出されなかった

Phase I Trial of Escalating-dose Cisplatin with 5-fluorouracil and Concurrent Radiotherapy in Chinese Patients with Esophageal Cancer

We defined the maximum-tolerated dose (MTD) of chemoradiotherapy (cisplatin (CDDP) with 5-fluorouracil (5-FU) and concurrent chemoradiotherapy) for Chinese patients with esophageal cancer. Twenty-one previously untreated patients with primary esophageal cancer were entered into this study. Escalating doses of CDDP with 5-FU were administered in a modified Fibonacci sequence, with concurrent conventional fractionation radiotherapy (CFR) of 60 Gy or 50 Gy. The starting doses were CDDP 37.5 mg/m2 on day 1, and 5-FU 500 mg/m2 on days 1-5, respectively. The regimen was repeated 4 times every 28 days. If no dose-limiting toxicity (DLT) was observed, the next dose level was applied. The procedures were repeated until DLT appeared. The MTD was declared to be 1 dose level below the level at which DLT appeared. DLT was grade 3 radiation-induced esophagitis at a dose level of CDDP 60 mg/m2 with 5-FU 700 mg/m2 and concurrent 60 Gy CFR. MTD was defined as CDDP 52.5 mg/m2 with 5-FU 700 mg/m2 and concurrent 50 Gy CFR. The MTD of CDDP with 5-FU and in concurrent chemoradiotherapy for Chinese patients with esophageal cancer is CDDP 52.5 mg/m2 on day 1 and 5FU 700 mg/m2 on days 1-5, repeated 4 times every 28 days, and concurrent 50 Gy CFR. Further evaluation of this regimen in a prospective phase II trial is ongoing.</p