【特刊综述】雄激素对骨骼肌的作用：对乏力的发展和治疗的意义

雄激素对骨骼肌合成有明显影响,随着年龄增大,雄激素的下降常伴随肌量和肌力的下降。这种肌量和肌功能的下降,被称为少肌症或肌体老化,是老年人体质弱化（男性化减退）进展的关键事项。也是导致快速机能衰退及其不良后果的关键。雄激素水平下降对老年男性体质弱化（男性化减退）的潜在影响和对躯体功能的促进治疗作用无疑已经引起了相当的关注。本综述概述了近期关于肌肉老化、少肌症、老年体质弱化的概念、定义,并评估了关于雄激素和老年体质弱化的研究进展。近期源于观测性和介入性研究的证据强烈支持雄激素对老年男性肌量的作用,但雄激素对肌力和特有的躯体功能的效用并不明确。研究显示,雄激素治疗在老年男性中通常有良好的耐受性,而近期的研究则关注于雄激素的高剂量治疗和对于心血管风险较高人群的治疗。雄激素受体调节剂（SARMs）的初期试验研究显示传统雄激素治疗对于老年患者在肌量和肌功能方面有相同的效用。将来的重要研究方向包括利用这类雄激素治疗并结合适用于不同老年患者群体促进躯体功能的运动训练,同时将更多地关注近期关于激素水平、身体成分及躯体功能间关系的观测性（回顾性）研究。     

The evolution of degenerative marrow (Modic) changes in the cervical spine in neck pain patients

Purpose

To evaluate the natural course of end plate marrow (Modic) changes (MC) in the cervical spine on MRI scans of patients with neck pain. A few longitudinal studies have assessed the development of MC over time in the lumbar spine but only two recent studies evaluated MC in the cervical spine in asymptomatic volunteers and those with whiplash. Thus, this study now reports on the natural course of MC in the cervical spine in symptomatic patients.

Methods

From the cervical MRI scans of 426 neck pain patients (mean age 61.2 years), 64 patients had follow-up MRI studies. The prevalence and types of MC were retrospectively assessed on the follow-up scans and compared to the original MRI findings.

Results

With an average of 2.5 years between the two MRI scans, the prevalence of MC type 1 (MC1) noted at baseline (7.4 % or 19 motion segments) slightly increased (8.2 % or 21 segments) but the prevalence of MC2 (14.5 % or 37 segments) increased considerably (22.3 % or 57 segments). In addition, 14 new MC1 segments and 8 new MC2 segments were noted. Twelve segments with MC1 at baseline converted to MC2 at follow-up. No conversion from MC2 to MC1 or reverting to a normal image was observed.

Conclusions

MC in the cervical spine are a dynamic phenomenon similar to the lumbar spine.     

Non‐invasive assessment of kidney allograft fibrosis with shear wave elastography: A radiological‐pathological correlation analysis

Objectives

To evaluate the use of shear wave elastography in assessment of kidney allograft tubulointerstitial fibrosis.

Methods

Shear wave elastography assessment was carried out by two independent operators in kidney transplant recipients who underwent allograft biopsy for clinical indications (i.e. rising creatinine >15% or proteinuria >1 g/day). Allograft biopsies were interpreted by the same pathologist according to the 2013 Banff Classification.

Results

A total of 40 elastography scans were carried out (median creatinine 172.5 μmol/L [interquartile range 133.8–281.8 μmol/L]). Median tissue stiffness at the cortex (22.6 kPa [interquartile range 18.8–25.7 kPa] vs 22.3 kPa [interquartile range 19.0–26.5 kPa], P = 0.70) and medulla (15.0 kPa [interquartile range 13.7–18.0 kPa] vs 15.6 kPa [interquartile range 14.4–18.2 kPa]) showed no significant differences between the two observers. Interobserver agreement was satisfactory (intraclass correlation coefficient of the cortex 0.84, 95% CI 0.70–0.92 and intraclass correlation coefficient of the medulla 0.88, 95% CI 0.78–0.94). The areas under the receiver operating characteristic curves for detection of tubulointerstitial fibrosis were estimated to be 0.75 (95% CI 0.61–0.89), 0.85 (95% CI 0.75–0.95) and 0.65 (95% CI 0.53–0.78) for cortical, medullary tissue stiffness and serum creatinine, respectively.

Conclusions

Shear wave elastography can be used as a non‐invasive tool to evaluate kidney allograft fibrosis with reasonable interobserver agreement and superior test performance to serum creatinine in detecting early tubulointerstitial fibrosis.     

Metatarsophalangeal joint of the great toe: normal MR,MR arthrographic,and MR bursographic findings in cadavers

OBJECTIVE: To demonstrate the normal anatomy of the metatarsophalangeal (MTP) joint of the great toe with MR imaging, MR arthrography, and MR bursography. MATERIALS AND METHODS: MR images of 12 cadaveric MTP joints of the great toe were obtained before and after arthrography, busography, or both. The MR appearances of all articular and periarticular structures were analyzed and correlated with those seen on anatomic sections. RESULTS: The sesamoid bones and ligaments, the deep transverse metatarsal ligament, and the tendon attachments of the abductor and adductor hallucis muscles were seen best in the coronal plane. The sagittal plane was best for evaluating the plantar plate, the articular cartilage, and the tendon attachments of the flexor and extensor hallucis brevis muscles. The main collateral ligaments were evaluated best in the axial plane. MR arthrography improved the visualization of all articular and periarticular structures except the collateral ligament complexes. MR bursography did not enhance the visualization of these structures. CONCLUSIONS: MR imaging and MR arthrography allow accurate visualization of the important anatomic structures in and about the MTP joint of the great toe.     

Use of E mu-PIM-1 transgenic mice short-term in vivo carcinogenicity testing: lymphoma induction by benzo[a]pyrene, but not by TPA

E mu-pim-1 transgenic mice are predisposed to develop lymphomas. Due to their low spontaneous tumour incidence and their increased sensitivity towards the lymphomagen ethylnitrosourea these mice may present an interesting model for short-term carcinogenicity testing. Here, we report on the further exploration of this transgenic mouse model with two additional carcinogens known to have, among others, the lymphohaematopoietic system as target, i.e. benzo[a]pyrene (B[a]P) and 12-O-tetradecanoylphorbol-13-acetate (TPA). B[a]P, given three times a week (by gavage) for 13 weeks at 4.3, 13 or 39 mg/kg body weight, resulted in a dose-related increase in lymphomas up to a 90% incidence in E(mu)-pim-1 mice during the observation period of 40 weeks. B[a]P also induced tumours of the forestomach within this observation period, though at a lower incidence and apparently equally effective in wildtype and transgenic mice. TPA, on the other hand, was unable to induce lymphomas (or tumours in any other organ) in either transgenic or wildtype animals within the observation period of 44 weeks, when applied dermally at the maximum tolerated dose of 3 microg/mouse, twice a week for 35 weeks. Molecular analysis showed that B[a]P-induced lymphomas in transgenic mice were of T-cell origin, 80% of which had elevated levels of c-myc expression. None of the lymphomas had increased N-myc expression and mutation analysis of the ras-gene family revealed a K-ras mutation in only one out of eight tumours investigated. Also, none of the lymphomas showed aberrant expression of p53 as determined by immunohistochemistry. It is concluded that the E mu-pim-1 mouse model will not be very suitable for short-term carcinogenicity testing in general: only genotoxic chemicals that have the lymphohaematopoietic system as target for carcinogenesis in wild- type mice, appear to be efficiently identified.      

Asymmetric atrophy of the supraspinatus muscle following tendon tear.

Muscle atrophy is a known consequence of muscle disuse, muscle denervation and tendon tear. Whereas after nerve injury muscle atrophies in the denervated area, the distribution of muscle atrophy following tear of its tendon is not known. Standardized MRI scans of 64 consecutive, painful shoulders were evaluated for supraspinatus tendon tearing, myotendinous retraction, supraspinatus muscle atrophy, fatty infiltration, ratio of the scapular (deep) and fascial (superficial) muscle area ("symmetry") and position of the central tendon within the supraspinatus fossa. There were thirteen shoulders with no and eleven shoulders with partial thickness supraspinatus tendon tears. In the forty cases with full thickness tendon tear, there was significant muscle atrophy and fatty infiltration. Atrophy of the fascial muscle portion was 43%, on the bony side it was 9% (p<0.005). The position of the central tendon within the supraspinatus fossa, was unaltered. Muscular changes following tendon tear occur highly asymmetrically: the muscle portion originating from the fascia primarily atrophies, the portion originating from the scapula primarily undergoes fatty infiltration. Muscular changes are not simply a consequence of muscle disuse, but dependent on architectural changes in the muscle.     

Cervical nerve root blocks: indications and role of MR imaging

PURPOSE: To examine whether magnetic resonance (MR) imaging findings of the cervical spine can predict pain relief after selective computed tomography (CT)-guided nerve root block and thus assist in the appropriate selection of patients who are suitable for this procedure. MATERIALS AND METHODS: Sixty consecutive patients with cervical radicular pain were examined with MR imaging and then treated with CT-guided cervical nerve root blocks (CNRBs). Various MR imaging findings were assessed and compared in terms of associated pain relief after CNRB. Pain relief was graded (0%-100%) by using a visual analogue scale (VAS). The relationship between MR imaging findings and level of pain relief was tested by using Mann-Whitney U and Kruskal-Wallis tests. RESULTS: The mean percentage of pain reduction at VAS grading was 46%. There was a significant relationship between pain relief level and both location of disk herniation (mean pain reductions of 41% at median or mediolateral locations and 64% at foraminal locations, P =.034) and location of nerve root compromise (mean pain reductions of 19% at intraspinal, 45% at foraminal entrance, and 58% at foraminal locations; P =.019). There was an inverse relationship between pain relief level and absence or presence of spinal canal stenosis (mean pain reductions of 29% when stenosis present and 53% when stenosis absent, P =.013). Other parameters were not significantly related to pain relief. CONCLUSION: MR imaging of the cervical spine assists in the appropriate selection of patients suitable for CNRB. Patients with foraminal disk herniation, foraminal nerve root compromise, and no spinal canal stenosis appear to have the greatest pain relief after this procedure.     

MR morphology of alar ligaments and occipitoatlantoaxial joints: study in 50 asymptomatic subjects

PURPOSE: To assess the magnetic resonance (MR) imaging appearance of the alar ligaments and joints in the upper cervical spine to determine the prevalence of structural alterations in asymptomatic individuals. MATERIALS AND METHODS: Fifty healthy individuals (31 men, 19 women) with a mean age of 30 years (range, 19-47 years) underwent coronal T1- and T2-weighted and transverse T1-weighted MR imaging. MR findings were analyzed independently by two musculoskeletal radiologists, with disagreements resolved in conference. RESULTS: Alar ligaments were detected in 42 (84%) (left side) and 38 (76%) (right side) of 50 individuals. The majority of ligaments (88%) and joints (58%) of the craniocervical junction (CCJ) were asymmetric. Asymmetry of the joint between C1 and C2 was less frequent (46%). Small amounts of fluid were detected in 8% of CCJ joints and 56% of C1-C2 joints in asymptomatic individuals. CONCLUSION: Asymmetry of alar ligaments, CCJ and C1-C2 facet joints, and joint effusions are common in asymptomatic individuals. The clinical relevance of these MR findings is therefore limited in the identification of the source of neck pain in symptomatic patients.     

Classification of trochlear dysplasia as predictor of clinical outcome after trochleoplasty

Purpose  

Sulcus-deepening trochleoplasty restores the trochlear groove in patients with patellofemoral instability and underlying trochlear dysplasia. There are types of dysplasia both with (B and D) and without (A and C) a supratrochlear spur. The aim of this study was to identify influencing factors for the clinical outcome following trochleoplasty.