大学サッカー選手における第5中足骨疲労骨折の発生因子

BACKGROUND: The pathogenesis of fifth metatarsal stress fractures remains uncertain. HYPOTHESIS: Physical characteristics and environmental factors, which have received limited attention in the literature thus far, might be involved in the development of fifth metatarsal stress fractures. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: To test the study hypothesis, a medical examination and survey of the living environment of collegiate soccer players was conducted and correlated with the existence of fifth metatarsal stress fractures. The survey and measurements were conducted in 273 male athletes from the same college soccer team between 2005 and 2013. A medical examination comprising assessment of stature, body weight, body mass index, foot-arch height ratio, toe-grip strength, quadriceps angle, leg-heel angle, functional reach test, single-leg standing time with eyes closed, straight-leg raise angle, finger-floor distance, heel-buttock distance, ankle joint range of motion, and a general joint laxity test were performed once a year, along with a questionnaire survey. The survey was also repeated when a fifth metatarsal stress fracture was diagnosed. The study participants were separated into a fifth metatarsal stress fracture injury group and a noninjury group. The measurement items and survey items were compared, and the association between the factors and the presence or absence of injuries was analyzed. RESULTS: Toe-grip strength was significantly weaker in the injury group compared with the noninjury group, suggesting that weak toe-grip is associated with fifth metatarsal stress fracture (P < .05). In addition, fifth metatarsal stress fractures were more common in the nondominant leg (P < .05). Between-group comparisons of the other items showed no statistically significant differences. CONCLUSION: The association between weak toe-grip strength and fifth metatarsal fracture suggests that weak toe-grip may lead to an increase in the load applied onto the lateral side of the foot, resulting in stress fracture. The finding of stress fracture being more common in the nondominant leg needs further study.博士（医学）・甲第660号・平成28年11月24日© The Author(s) 2015 : This open-access article is published and distributed under the Creative Commons Attribution - NonCommercial - No Derivatives License (http://creativecommons.org/ licenses/by-nc-nd/3.0/), which permits the noncommercial use, distribution, and reproduction of the article in any medium, provided the original author and source are credited. You may not alter, transform, or build upon this article without the permission of the Author(s). For reprints and permission queries, please visit SAGE’s Web site at http://www.sagepub.com/journalsPermissions.nav

Study on the Principle of Photosynthetic Light Energy Conversion Based on Divergence of Chlorophyll Molecules

The composition of photosystem II (PSII) in the chlorophyll (Chl) d-dominatedcyanobacterium Acaryochloris marina MBIC 11017 was investigated to enhance the generalunderstanding of the energetics of the PSII reaction center. We first purifiedphotochemically active complexes consisting of a 47 kDa chlorophyll protein (CP47), CP43’(PcbC), D1, D2, cytochrome b559, PsbI, and an unknown small polypeptide. The pigmentcomposition per two pheophytin (Phe) a molecules was 55 ± 7 Chl d, 3.0 ± 0.4 Chl a, 17 ± 3α-carotene, and 1.4 ± 0.2 plastoquinone-9. A special pair was detected by a reversibleabsorption change at 713 nm (P713) together with a cation radical band at 842 nm. FTIRdifference spectra of the specific bands of a 3-formyl group allowed assignment of the specialpair. The combined results indicate that the special pair includes a Chl d homodimer.The primary electron acceptor was shown by photoaccumulation to be Phe a, and itspotential was shifted to a higher value than that in the Chl a/Phe a system. The overallenergetics of PSII in the Chl d system adapt to changes in the redox potentials, with P713as the special pair utilizing lower light energy at 713 nm. Our findings support the ideathat changes in photosynthetic pigments combine with modification of the redox potentialsof electron transfer components to give rise to energy changes in the total reaction system.■原 著■ 2007 年度神奈川大学総合理学研究所共同研究助成論

Closed reduction of a posterior sternoclavicular joint dislocation: A case report

Sternoclavicular joint dislocation (SCJD) is a rare injury; there are only two reported cases of SCJD that have occurred during judo practice. We present a case of an 18-year-old male athlete who fell while practicing judo and experienced upper left chest pain. He was diagnosed with posterior SCJD at another institute before being transferred to our hospital. Closed reduction was initially not possible using traditional methods. Reduction was eventually accomplished by clamping the proximal end of the clavicle using bone forceps and rotating it while pulling it upward. Many authors have reported that closed reduction is difficult if not performed within 48 h after SCJD injury. However, we were able to achieve closed reduction approximately 72 h after injury. We found that reduction might be easily accomplished by pulling the proximal end of the clavicle up and rotating it when other closed reduction methods are unsuccessful. Keywords: Posterior sternoclavicular joint dislocation, Judo, Closed reductio