軟骨下ドリリングを施行したラット膝関節軟骨欠損をアテロコラーゲン膜にて被覆すると、欠損部に骨新生が誘導される

内容の要旨 , 審査の要旨広島大学(Hiroshima University)博士(医学)Philosophy in Medical Sciencedoctora

Acceleration of healing of the medial collateral ligament of the knee by local administration of synthetic microRNA-210 in a rat model

AbstractBackgroundInjury to the medial collateral ligament (MCL) of the knee joint is the most common ligament injury of the knee. Ligament healing generally takes a long time. Micro-ribonucleic acid (miRNA) is one of the noncoding RNAs and plays a crucial role in physiological function; miRNA (miR)-210 is known as a potent factor of angiogenesis, which is an important initiator of ligament healing. The purpose of this study is to examine the effect of local injection of double-stranded (ds) miR-210 on the healing of the MCL of rat knee joint.MethodsMCLs of Sprague-Dawley rats were cut transversely. After the fascia and skin were sutured, dsmiR-210 or control dsRNA was injected into the injured site of MCL. At 2 weeks and 4 weeks, histological analysis and immunofluorescence staining of vascular endothelial growth factor, isolectin B4, collagen type 1, and Ki67 as well as a mechanical test were performed. Analysis of complementary deoxyribonucleic acid (cDNA) microarray data was performed at 1 week.ResultsHistological analysis showed that parallel fibres in the injured site were organised at 2 weeks and became thicker at 4 weeks in the miR-210-treated group, whereas the injured site in controls was filled with loose fibrous tissues and was thinner than that in the miR-210-treated group. The number of blood vessels in the miR-210-treated group was significantly higher than that in controls (p < 0.05), and vascular endothelial growth factor, Ki67, and collagen type 1 in the miR-210-treated group were intensely expressed in the repaired site as compared to the control group. The mechanical test indicated that the ultimate failure load in the miR-210-treated group was significantly higher than that in the control group at 2 weeks. The cDNA microarray analysis showed significant upregulation of genes related to cell proliferation and cell differentiation, and genes involved in negative regulation of apoptosis.ConclusionThis study showed that local injection of dsmiR-210 could accelerate MCL healing in rat, which is likely due to stimulation of angiogenesis at the healing site

Longitudinal changes in dynamic characteristics of neonatal external and middle ears

金沢大学理工研究域フロンティア工学系ObjectivesNeonates have smaller and less mature ears than adults. Developmental changes in structure and function continually occur after birth and may affect the diagnostic results obtained by audiometric assessment instrumentation, such as tympanometry and otoacoustic emission. In the present study, we investigated longitudinal changes in external and middle ear dynamic characteristics by performing sweep frequency impedance (SFI) tests.MethodsSFI tests were longitudinally performed on healthy Japanese neonates (1 female and 1 male) from birth to 3 and 5 months, respectively. A sound of sweeping sinusoidal frequency, ranging from 0.1 kHz to 2 kHz, was presented to the ear canal at 50-daPa intervals of static pressure from +200 to −200 daPa. Test results were expressed a curve showing the sound pressure level (SPL) relative to probe tone frequency, called SPL curve.ResultsThe first fluctuation in resonance frequency (RF1) and SPL (ΔSPL1), related to the external ear, showed significant developmental changes as chronological age increased; that is, RF1 and ΔSPL1 were respectively increased and decreased and thereafter became unmeasurable by 5 months of age. In contrast, the second fluctuation in resonance frequency (RF2) and SPL (ΔSPL2), related to the middle ear, did not show significant changes over the measurement period.ConclusionsThe present results suggest that the dynamic characteristics of the external ear canal wall changed with increases in chronological age; the resonance of the wall at about 0.3 kHz at birth tended to increase to about 0.7 kHz and to be unmeasurable by 5 months of age, while those of the middle ear did not significantly changed. These results showing how neonatal-ear dynamics changes with chronological age may be an important key in further hearing research and the development of hearing devices and diagnostic tools suitable for neonates.Embargo Period 12 month

Analysis by Sweep Frequency Impedance (SFI) meter of 226-Hz and 1,000-Hz tympanometries in neonates

Conventional 226-Hz tympanometry has been acknowledged as a reliable method for detecting middle ear dysfunction in adults and children. However, its application has proved to be inaccurate in neonates younger than 7 months of age. In the present study, therefore, tympanograms of neonates were derived based on sweep frequency impedance (SFI) data and an attempt was made to investigate the reason why conventional tympanometry is inadequate for neonates. Analysis of neonatal tympanograms revealed that the application of a conventional 226-Hz probe tone leads to either a type A or a type M tympanogram. This is possibly due to the intrinsic oscillatory behavior of the external ear canal wall caused by its resonance at around 226 Hz. (c) 2017 Published by Elsevier B.V