Effects of Each Phase of Anterior Cruciate Ligament Reconstruction Surgery on Joint Contracture in Rats

Background Although anterior cruciate ligament reconstruction surgery is known to cause joint contracture, the mechanisms of this process are unknown. We aimed to assess the effects of transection of this ligament and each phase of reconstruction surgery on contracture formation. Materials and methods Rats were divided into groups according to treatment received: sham (arthrotomy), ligament transection, ligament transection plus bone drilling, and ligament reconstruction. Surgery was performed on the right knee. Untreated left knees in the sham group were used as controls. Results At 7 and 28 d post-surgery, range of motion before myotomy, mainly representing myogenic contracture, was restricted in the sham and ligament transection groups, and more so in the bone drilling and reconstruction groups. Restricted range of motion after myotomy, representing arthrogenic contracture, was detected at both timepoints in the bone drilling and reconstruction groups, but not in the sham or ligament transection groups. At 3 d post-surgery, although a large blood clot was observed in all three treatment groups, only the bone drilling and reconstruction groups showed significant joint swelling. At 7 d post-surgery, inflammatory-cell infiltration into the joint capsule was most apparent in the bone drilling and reconstruction groups, and joint capsule fibrosis was also most apparent in these groups at 7 and 28 d post-surgery. Conclusions Our results suggest that (1) myogenic contracture after anterior cruciate ligament reconstruction is caused by arthrotomy and aggravated by bone drilling, and (2) arthrogenic contracture is mostly due to bone drilling, which triggers an inflammation–fibrosis cascade

Synthesis of 11C-labeled acyclic retinoid,[11C]peretinoin, with high brain permeability

全-trans-レチノイン酸（ATRA）およびその人工類縁体は核内受容体の活性化を通して抗がん作用を示すが，近年，中枢神経系変性疾患に対する改善効果にも大きな注目が集まり，国内外でレチノイド類のPET脳イメージングが試みられている。本研究は，脳疾患に関係する最適治療薬の開発に直結する高い脳移行性を有するPETプローブの開発を目的とした。ATRAの化学的および代謝不安定性を鑑み，より安定な非環式レチノイド（ぺレチノイン）に着目し，パラジウム錯体を介する高速カップリング反応による高効率な11C標識化によりPETトレーサーの安定供給を可能にした。続いて，ラットおよびサルを用いた脳PET研究により11C標識ペレチノインの高い脳移行性を観測した。これらの成果は，これまでのレチノイド類のがん研究に加えて新たに脳研究分野を加え，レチノイド類の疾患診断薬や治療薬の開発を助長する重要な知見である。第61回　日本核医学会学術総

Clinical practice guidelines for high-resolution breast PET, 2019 edition

Breast positron emission tomography (PET) has had insurance coverage when performed with conventional whole-body PET in Japan since 2013. Together with whole-body PET, accurate examination of breast cancer and diagnosis of metastatic disease are possible, and are expected to contribute significantly to its treatment planning. To facilitate a safer, smoother, and more appropriate examination, the Japanese Society of Nuclear Medicine published the first edition of practice guidelines for high-resolution breast PET in 2013. Subsequently, new types of breast PET have been developed and their clinical usefulness clarified. Therefore, the guidelines for breast PET were revised in 2019. This article updates readers as to what is new in the second edition. This edition supports two different types of breast PET depending on the placement of the detector: the opposite-type (positron emission mammography; PEM) and the ring-shaped type (dedicated breast PET; dbPET), providing an overview of these scanners and appropriate imaging methods, their clinical applications, and future prospects. The name “dedicated breast PET” from the first edition is widely used to refer to ring-shaped type breast PET. In this edition, “breast PET” has been defined as a term that refers to both opposite- and ring-shaped devices. Up-to-date breast PET practice guidelines would help provide useful information for evidence-based breast imaging