Lack of dystrophin influences muscle inflammation but not myogenic regulatory factors after eccentric exercise in mdx mice

Abstract Aim: To investigate the consequences of chronic eccentric exercise in histopathology, inflammatory, and myogenic regulatory factors response in gastrocnemius muscle of X-chromosome-linked muscular dystrophy (mdx) mice. Method: Male mdx and control mice (C57BL/10 lineage) were distributed in the following groups: Sedentary Control (SC), Trained Control (TC), Sedentary Mdx (S-Mdx), and Trained Mdx (T-Mdx). Trained animals were subjected to downhill running for 7 weeks. Gastrocnemius was submitted to histopathological analysis and immunoexpression of Cyclooxygenase-2 (COX-2) and myogenic regulatory factors (myoD and myogenin). Results: The exercise influenced inflammation response as demonstrated by the increased COX-2 immunoexpression in T-Mdx. Interestingly, Myogenic regulatory factors revealed that the lack of dystrophin has not been influenced myoD and the increase of myogenin occurred due to exercise and was not aggravated by the absence of dystrophin. Conclusion: In conclusion, an eccentric exercise in gastrocnemius of mdx mice was characterized by an intense inflammatory process without myogenic response. These findings suggest that special attention should be given to inflammatory aspects related to COX-2 associated with a decrease of myoD expression, as biomarkers in motor rehabilitation programs.

Primary Rhabdomyosarcoma of the Breast: Study of Three Cases at One Institution with a Review of Primary Breast Sarcomas

BACKGROUND: Primary breast sarcoma (PBS) is rare, comprising approximately 1% of breast malignancies. Rhabdomyosarcoma (RMS) accounts for an extremely small proportion of PBSs, often leading to delayed histologic confirmation. METHODS: Upon reviewing Asan Medical Center’s pathology database between 2000 and 2018, 41 PBS cases were retrieved, including three cases of primary RMS of the breast. Their clinicopathological features were analyzed, and the literature related to PBS and primary RMS of the breast was reviewed. RESULTS: We identified three primary breast RMS cases from our institution database, comprising 7.3% of PBS: one case each of spindle cell/sclerosing RMS (ssRMS), alveolar RMS (aRMS), and embryonal RMS (eRMS). All cases involved adolescents or young adults (14, 16, and 25 years, respectively) who underwent mastectomy or radiotherapy and were confirmed using immunohistochemical testing for myogenin, desmin, and myogenic differentiation. The ssRMS patient experienced recurrence at the operation site 4 months post-surgery despite undergoing concurrent chemoradiotherapy. The aRMS patient had multiple metastases at diagnosis and showed FAX3-FOXO1 fusion transcripts; she died 22 months after the diagnosis. The eRMS patient had enlarged axillary lymph nodes; post-radiotherapy, the lesion recurred as multiple metastases to the bone and lung. She died 18 months post-diagnosis. CONCLUSIONS: Our experience on RMS cases suggests that spindle cell or small round cell malignancy in breasts of young female should raise suspicion for the possibility of primary or secondary RMS. To our knowledge, this is the second report of primary breast ssRMS and it may help clinicians who encounter this rare disease in the future.

Uterine Malignant Mixed Müllerian Tumors Following Treatment with Selective Estrogen Receptor Modulators in Patients with Breast Cancer: A Report of 13 Cases and Their Clinicopathologic Characteristics

BACKGROUND: Breast cancer treatment with selective estrogen receptor modulators (SERMs) increases the incidence of uterine malignant mixed Müllerian tumors (uMMMTs). We examine clinicopathologic characteristics and prognosis of SERM-associated uMMMTs (S-uMMMTs) and discuss possible pathogenetic mechanisms. METHODS: Among 28,104 patients with breast cancer, clinicopathologic features and incidence of uMMMT were compared between patients who underwent SERM treatment and those who did not. Of 92 uMMMT cases that occurred during the same period, incidence, dose, and duration of SERM treatment, as well as overall survival rate, were compared for patients with breast cancer who underwent SERM treatment and those who did not (S-uMMMT vs NS-uMMMT) and for patients without breast cancer (de novo-uMMMT). Histopathological findings and immunophenotypes for myogenin, desmin, p53, WT-1, estrogen receptor (ER) α, ERβ, progesterone receptor, and GATA-3 were compared between S-uMMMT and de novo-uMMMT. RESULTS: The incidence of S-uMMMT was significantly higher than that of NS-uMMMT (6.35-fold). All patients with SERM were postmenopausal and received daily 20–40 mg SERM. Cumulative SERM dose ranged from 21.9 to 73.0 g (mean, 46.0) over 39–192 months (mean, 107). Clinicopathologic features, such as International Federation of Gynecology and Obstetrics stage and overall survival, were not significantly different between patients with S-uMMMT and NS-uMMMT or between patients with S-uMMMT and de novo-uMMMT. All 11 S-uMMMT cases available for immunostaining exhibited strong overexpression/null expression of p53 protein and significantly increased ERβ expression in carcinomatous and sarcomatous components. CONCLUSIONS: SERM therapy seemingly increases risk of S-uMMMT development; however, clinicopathologic features were similar in all uMMMTs from different backgrounds. p53 mutation and increased ERβ expression might be involved in the etiology of S-uMMMT.

Intraspinal metastasis of alveolar rhabdomyosarcoma: A case report / 北京大学学报(医学版)

This paper reported a case of cervical intraspinal metastasis of alveolar rhabdomyosarcoma (ARMS). The clinicopathological features, surgical treatment, chemotherapy and prognosis were introduced and the current literature was reviewed. The diagnosis, differential diagnosis, treatment, molecular features and prognosis of the disease were comprehensively analyzed to improve clinicians' knowledge of this rare disease. The primary lesion appeared about 1 year ago which was painless mass of left hand whose size was about 2 cm×2 cm. After conservative treatment, the mass gradually enlarged and the mass was resected. Postoperative pathology revealed embryonic rhabdomyosarcoma. Postoperative chemotherapy with recombinant human endostatin, liposomal doxorubicin and ifosfamide was performed. The left neck mass was found about 3 months ago, and then the left neck mass was resected under general anesthesia. Postoperative pathological examination showed small round cell malignant tumors. Severe left upper extremity pain began about 2 weeks ago with nocturnal pain and supine pain. Non-steroidal anti-inflammatory drugs were needed to relieve pain which was accompanied by numbness and weakness of the left upper extremity. MRI showed a intraspinal tumor at C5. The left thumb and index finger were absent. Hypoesthesia, muscle atrophy and hypotonia of the left upper limb were confirmed. The muscle strength of biceps brachii and deltoid muscle of the left upper limb was grade 0, the muscle strength of extensor carpus and interphalangeal muscle was grade II, the muscle strength of intrinsic muscles of hands was grade I. The tendon reflex of the left upper limb disappeared. Intraspinal mass was removed and the pain was relieved. But there was no significant change in the muscle strength of the left upper limb. Pathological examination revealed small cell malignancies which were poorly differentiated with diffuse patchy distribution and disordered arrangement. The tumor cells had round, oval or irregular nuclei, and few cytoplasms were positive for Myogenin and MyoD1. FISH test of FOXO1 gene was positive. More than 50% of nuclei showed redgreen signal separation, and the distance between redgreen signals was larger than double diameter of the signal points, which supported ARMS. Total resection of intraspinal tumors was achieved and postoperative chemotherapy was admitted. But intraspinal disseminated metastasis occurred rapidly. ARMS was rare, aggressive tumor with poor prognosis. Subdural metastasis was rare. Correct diagnosis and classification can be made only with help of modern molecular diagnostic methods, which is effective to guide the treatment.

Rheumatoid arthritis-increased gene expressions in muscle atrophy are restored back to control as a response to acute resistance exercise / Estímulo agudo de musculação promove regulação de genes alterados pela atrofi a muscular

This study had as objective to analyze the acute eff ects of resistance exercise (RE) on the mRNA levels of the following genes (MyoD, myogenin, IGF-1, atrogin-1, MuRF-1, and myostatin) in rheumatoid arthritis (experimental arthritis). Therefore, 26 females rats were randomly allocated into four groups, control (CT, n=7), exercise (Ex, n=6), rheumatoid arthritis (RA, n=6) and RA with exercise (RAEx, n=7). Met-BSA was injected into the tibiotarsal joint in the RA and RAEx groups. After 15 days from injection, the animals were submitted to an acute bout of RE and six hours post protocol the animals were euthanized. We evaluated the joint thickness, infl ammation score, cross-sectional area (CSA) of gastrocnemius muscle fi bers and mRNA expression of the IGF-1, MyoD, myogenin, myostatin, MuRF-1, atrogin-1 and GAPDH. It was observed that the joint thickness and score strongly increased in arthritic rats (p <0.001) while the CSA decreased (p ≤ 0.05). Increased mRNA levels of IGF-1 (2.0 fold), myostatin (4.5 fold), atrogin-1 (2.5 fold), MyoD (3.7-fold) and myogenin (5 fold) were observed in muscle of arthritic rats. The mRNA expression of myostatin, atrogin-1, MyoD and myogenin decreased in the RAEx group. In this way, we can conclude that experimental arthritis-increased gene expressions in muscle atrophy myostatin, atrogin-1, MyoD and myogenin) are restored back to control as a response to acute RE....(AU)

O presente estudo teve como objetivo analisar o efeito agudo do Exercício com pesos sobre os níves de mRNA de genes envolvidos no anabolismo ou catabolismo muscular em um modelo experimental de Artrite Reumatóide. Para tanto, 26 ratas fêmeas foram randomicamente alocadas em quatro grupos, controle (CT, n=7), Exercício (Ex, n=6), Artrite Reumatóide (AR, n=6) e Artrite Reumatóide com exercício (AREx, n=7). Uma substância contendo Albumina bovina metilada foi injetada na articulação tíbio-tarsal nos grupos AR e AREx para indução da Artrite Reumatóide. Após 15 dias da injeção, os animais foram submetidos a um estímulo agudo de treinamento com pesos e 6 horas após o exercício os animais foram eutanasiados. Nós avaliamos a espessura da articulação, escore de infl amação, a área de secção transversa (AST) das fi bras do músculo Gastrocnêmio e a mRNA de IGF-1, MyoD, Myogenina (genes envolvidos no anabolismo muscular), e MuRF-1, atrogina-1 (genes envolvidos no catabolismo muscular), além do gene controle , GAPDH. Foi observado que a espessura articular e o escore de infl amação aumentaram fortemente nas ratas induzidas a Artrite Reumatóide (p <0,001), enquanto a AST reduziu (p ≤ 0,05). Um aumento nos níveis de mRNA de IGF-1 (2,0 vezes), miostatina (4,5 vezes), atrogina-1 (2,5 vezes), MyoD (3,7 vezes) e miogenina (5 vezes) foi observado no músculo das ratas induzidas a Artrite Reumatóide. mRNA de miostatina, atrogina-1, MyoD e miogenina reduziu no grupo RAEx. Desta forma, podemos concluir, que o modelo experimental de Artrite Reumatóide induziu um aumento da expressão de genes durante a atrofi a muscular (myostatin, atrogin-1, MyoD and myogenin) e que estas alterações foram reguladas pelo Exercício com peso....(AU)

Effects of eldecalcitol and ibandronate on secondary osteoporosis and muscle wasting in rats with adjuvant-induced arthritis

OBJECTIVES: Rheumatoid arthritis (RA) is characterized by chronic inflammation of the synovium, progressive erosion of the articular cartilage, and joint destruction. RA also causes secondary osteoporosis and muscle wasting. We investigated the effects of ibandronate (IBN), a bisphosphonate; eldecalcitol (ELD), an active vitamin D3 derivative; and combination treatment with both agents on secondary osteoporosis and muscle wasting using adjuvant-induced arthritis rats. METHODS: Arthritis was induced in 8-week-old male Lewis rats. Rats were randomized into 4 treatment groups and an untreated normal control group: IBN (subcutaneously, once every 2 weeks, 10 µg/kg), ELD (orally, once daily, 30 ng/kg/day), IBN + ELD, vehicle, and control. Paw thickness measurements were performed for evaluation of arthritis. The femur was scanned using dual-energy X-ray absorptiometry. Cross-sectional areas of left tibialis and anterior muscle fibers and the expression of MuRF1, atrogin-1, MyoD, and myogenin in the gastrocnemius muscle were measured to evaluate muscle wasting. RESULTS: IBN and/or ELD increased bone mineral density (BMD) in the femur. In addition, there was an additive effect of combination treatment compared with single treatments for BMD. However, IBN and/or ELD did not inhibit muscle wasting in adjuvant-induced arthritis rats. CONCLUSIONS: Combination treatment with IBN and ELD may be effective for secondary osteoporosis associated with RA. Other treatments are necessary for muscle wasting associated with RA. Studies in humans are needed to confirm these findings.

Evaluation of skeletal muscle regeneration in experimental model after malnutrition / Avaliação da regeneração do músculo esquelético em modelo experimental após desnutrição

Abstract The aim of this study was to analyze muscle regeneration after cryoinjury in the tibialis anterior muscle of young rats that were malnourished and then recovered. Forty Wistar rats were divided into a nourished group that received a normal protein diet (14% casein) for 90 days and a malnourished and recovered rats group (MR) that was submitted to 45 days of malnutrition with a hypoproteic diet (6% casein) followed by 45 days of a normal protein diet (14% casein). After the recovery period, all of the animals underwent cryoinjury in the right tibialis anterior muscle and euthanasia after 7, 14 and 21 days. The amount of connective tissue and the inflammation area was higher in the malnutrition recovered injury MR group (MRI) at 14 days post-injury (p < 0.05). Additionally, the cross-sectional area (CSA) of the regenerated fibers was decreased in the MRI (p < 0.05). The MyoD and myogenin protein levels were higher in the nourished injury group. Similar levels of TGF-β1 were found between groups. The proposed malnutrition protocol was effective in showing delayed changes in the regeneration process of the tibialis anterior muscle of young rats. Furthermore, we observed a delay in muscle repair even after nutritional recovery.

Resumo O objetivo do presente estudo foi analisar a regeneração muscular após criolesão no músculo tibial anterior de ratos jovens desnutridos e recuperados. Foram utilizados 40 ratos da linhagem Wistar, divididos em 2 grupos: ratos nutridos receberam dieta normoproteica (14% de caseína) por 90 dias; e ratos desnutridos e recuperado submetidos a duas fases nutricionais pós-desmame, correspondendo a 45 dias de desnutrição com dieta hipoproteica (6% caseína), seguida por 45 dias de dieta normoproteica (14% caseína). Ao completar a fase de recuperação, todos os animais foram submetidos à criolesão no músculo tibial anterior direito e a eutanasia ocorreu 7, 14 e 21 dias após a lesão. A quantidade de tecido conjuntivo e a área de inflamação 14 dias pós-lesão foi maior no grupo desnutrido, recuperado e lesado (MRI – malnourished, recovered and injured group) (p < 0,05). A área de secção transversa (AST) das fibras regeneradas do grupo MRI foi menor (p < 0,05). O conteúdo das proteínas MyoD e Miogenina foi maior no grupo nutridos e lesados. A citocina TGF-β1 não apresentou diferença entre os grupos. O protocolo proposto foi eficaz para demonstrar alterações no processo de regeneração do músculo tibial anterior de ratos jovens, atrasando o reparo muscular mesmo após a recuperação nutricional.

Implantation of muscle satellite cells overexpressing myogenin improves denervated muscle atrophy in rats

This study evaluated the effect of muscle satellite cells (MSCs) overexpressing myogenin (MyoG) on denervated muscle atrophy. Rat MSCs were isolated and transfected with the MyoG-EGFP plasmid vector GV143. MyoG-transfected MSCs (MTMs) were transplanted into rat gastrocnemius muscles at 1 week after surgical denervation. Controls included injections of untransfected MSCs or the vehicle only. Muscles were harvested and analyzed at 2, 4, and 24 weeks post-transplantation. Immunofluorescence confirmed MyoG overexpression in MTMs. The muscle wet weight ratio was significantly reduced at 2 weeks after MTM injection (67.17±6.79) compared with muscles injected with MSCs (58.83±5.31) or the vehicle (53.00±7.67; t=2.37, P=0.04 and t=3.39, P=0.007, respectively). The muscle fiber cross-sectional area was also larger at 2 weeks after MTM injection (2.63×103±0.39×103) compared with MSC injection (1.99×103±0.58×103) or the vehicle only (1.57×103±0.47×103; t=2.24, P=0.049 and t=4.22, P=0.002, respectively). At 4 and 24 weeks post-injection, the muscle mass and fiber cross-sectional area were similar across all three experimental groups. Immunohistochemistry showed that the MTM group had larger MyoG-positive fibers. The MTM group (3.18±1.13) also had higher expression of MyoG mRNA than other groups (1.41±0.65 and 1.03±0.19) at 2 weeks after injection (t=2.72, P=0.04). Transplanted MTMs delayed short-term atrophy of denervated muscles. This approach can be optimized as a novel stand-alone therapy or as a bridge to surgical re-innervation of damaged muscles.

Effects of exogenous recombinant human basic fibroblast growth factor on the healing of muscles in rats after deep tissue injury of pressure ulcers / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the effect of exogenous recombinant human basic fibroblast growth factor (rhbFGF) on the healing of muscles in rats after deep tissue injury of pressure ulcers.</p><p><b>METHODS</b>Forty-eight SD rats were randomly divided into normal control group, injury control group, post injury day (PID) 4 group, PID 7 group, PID 14 group, PID 21 group according to the random number table, with 8 rats in each group. The rats in normal control group did not receive any treatment, whereas the rats in the latter 5 groups were established the deep tissue injury of pressure ulcer model on both sides of the gracilis muscle on the hind limb. The rats in injury control group did not receive any treatment after injury, while the rats in the latter 4 groups were given subcutaneous injection of 0.1 mL rhbFGF to the left gracilis in a dosage of 100 µg/mL immediately after injury, and an equal volume of normal saline (NS) was injected to right gracilis, once every other day. The rats in injury control group were sacrificed immediately after injury, and the rats in normal control group were sacrificed at the same time point. The rats in the other 4 groups were sacrificed on PID 4, 7, 14, 21, and the gracilis muscles on both sides were harvested respectively. The morphology of the gracilis muscle was examined after HE staining. The expression of myogenin in the tissues was detected by immunofluorescence method. The levels of muscle structural proteins myosin heavy chain (MyHC), phosphorylated protein kinase B (Akt), and phosphorylated mammalian target of rapamycin (mTOR) were determined by Western blotting. Data were processed with one-way analysis of variance and LSD test.</p><p><b>RESULTS</b>(1) In normal control group, the nuclei of graciles cells were in uniform size, and they were closely arranged with clear structure, and there were no significant infiltration of inflammatory cells. In injury control group, the nuclei of graciles cells showed signs of pyknosis, dissolution, fracture and structural disorder. Swelling of muscle cells, inflammation infiltration, structural disorder and other pathological signs of injury phenomena in graciles of PID 4 group, PID 7 group, PID 14 group, PID 21 group after rhbFGF treatment were milder compared with those after NS treatment. In addition, the numbers of regenerated myocytes in graciles of PID 4 group, PID 7 group, PID 14 group, PID 21 group after rhbFGF treatment were higher than those after NS treatment. (2) The numbers of graciles myogenin positive cells in normal control group and injury control group were respectively 28 ± 17 and 42 ± 28. The numbers of graciles myogenin positive cells in PID 4 group, PID 7 group, PID 14 group after NS treatment were 100 ± 50, 196 ± 87, 460 ± 110 respectively, while the numbers of graciles myogenin positive cells in PID 4 group, PID 7 group, PID 14 group after rhbFGF treatment were 174 ± 34, 717 ± 182, 613 ± 122 respectively, and the numbers of graciles myogenin positive cells after rhbFGF treatment were significantly higher than those after NS treatment in each group(P < 0.05 or P < 0.01). The number of graciles myogenin positive cells in PID 21 group after rhbFGF treatment was 109 ± 34, which was significantly lower than that after NS treatment (218 ± 71, P < 0.05). (3) The expression of MyHC in graciles in normal control group was high, which was decreased in injury control group. Both the expressions of MyHC in graciles in PID 4 group, PID 7 group, PID 14 group, PID 21 group after treatment of NS and rhbFGF showed a trend of gradual elevation, while the expressions of MyHC in graciles after rhbFGF treatment were significantly higher than those after NS treatment (P < 0.05 or P < 0.01). The expression of MyHC in graciles in PID 21 group showed a high level, and it was similar to that of the normal control group (P > 0.05). The expressions of phosphorylated Akt and phosphorylated mTOR in graciles of normal control group were low, and the expression of phosphorylated Akt in graciles increased in injury control group, while the expression of phosphorylated mTOR in graciles decreased in injury control group. The expressions of phosphorylated Akt and phosphorylated mTOR in graciles of PID 4 group, PID 7 group, PID 14 group, PID 21 group after treatment with rhbFGF showed a trend of elevation in the beginning but declined afterwards. The expressions of phosphorylated Akt and phosphorylated mTOR in graciles of PID 4 group after rhbFGF treatment were significantly lower than those after NS treatment (P <0 .05 or P < 0.01). The expressions of phosphorylated Akt and phosphorylated mTOR in graciles of PID 7 group, PID 14 group, PID 21 group after rhbFGF treatment were significantly higher than those after NS treatment (P < 0.05 or P < 0.01).</p><p><b>CONCLUSIONS</b>Exogenous rhbFGF may effectively facilitate the healing of muscle structure and accelerate the regeneration of muscles in rats after deep tissue injury of pressure ulcers, and its mechanism may be related to the improvement of the expression of myogenin and enhancement of the expression of protein of muscle growth-related signaling pathways.</p>

Childhood pleuropulmonary blastoma: a clinicopathologic study of 16 cases / 中华病理学杂志

<p><b>OBJECTIVE</b>To study the clinicopathological and immunohistochemical features, histogenesis and prognosis of pleuropulmonary blastoma (PPB) in children.</p><p><b>METHODS</b>PPB specimens from 16 pediatric cases with an age ranging from 1 year and 7 months to 5 years and 3 months (mean age of 3 years) were retrieved and analyzed by routine histological, immunohistochemical and electron methods.</p><p><b>RESULTS</b>Among 16 patients, there were 2 type I, 7 type II and 7 type III PPB cases. Type I PPB as multilocular cystic structure, consisted of thin fibrous wall lining the respiratory epithelium, subepithelial primitive blastema or immature mesenchymal cells, with or without rhabdomyoblastic differentiation or cartilage; Type II PPB as cystic-solid tumor, comparing with type I, consisted of intracystic components with appearance of anaplastic tumor cells. Type III PPB consisted of completely solid mass, the same as the solid region of type II, had mixed pattern including blastema, undifferentiated spindle-cell proliferations and sarcomas. In addition, anaplastic tumor cells and intra-and extra- cytoplasmic eosinophilic globules were also commonly present. Epithelial components in PPB were benign. Immunohistochemical study showed primitive mesenchymal differentiation of tumors. All cases were positive for vimentin, desmin, myogenin and SMA in tumors with skeletal muscle differentiation, S-100 was positive in tumors with cartilage differentiation. All tumors were negative for synaptophysin, CD99, and CD117. Benign epithelial components were positive for AE1/AE3 and EMA. In 12 cases, electron microscopy revealed few organelles in the primitive mesenchymal cells and rich heterochromatin in mesenchymal cells, the latter also demonstrating cytoplasmic myofilament dysplasia. Nine cases had clinical follow-up ranging from 5 to 48 months, of which 4 patients died.</p><p><b>CONCLUSIONS</b>PPB is a rare lung neoplasm of children under the age of 6 years, with distinct pathological morphology. PPB may arise from lung or pleura mesenchymal cells and has a poor clinical outcome.</p>

Extracardial rhabdomyoma: a clinicopathologic analysis of 9 cases / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate the clinicopathologic characteristics, differential diagnosis and biological behavior of extracardiac rhabdomyoma.</p><p><b>METHODS</b>Nine cases of extracardiac rhabdomyoma diagnosed between January of 1997 and July of 2014 were reviewed. The clinical, pathologic and immunohistochemical profiles were evaluated.</p><p><b>RESULTS</b>There were 5 males and 4 females at diagnosis with age ranging from 2 years and three months to 59 years (mean, 37.6 years). Sites included the head and neck region (7 cases), chest (1 case ) and vagina wall (1 case). Clinically, most cases manifested as a subcutaneous nodule or as a submucosal polypoid lesion with a mean diameter of 3.2 cm. Histologically, 4 were adult-type rhabdomyoma characterized by tightly packed large round or polygonal rhabdomyoblasts with abundant eosinophilic to clear cytoplasm; 3 were myxoid variant of fetal rhabdomyoma composed of immature myofibrils, spindled and primitive mesenchymal cells embedded in a myxoid background, 1 was an intermediate form of fetal rhabdomyoma consisting of densely arranged differentiated myoblasts with little myxoid stroma; 1 was a genital rhabdomyoma composed of elongated or strap-like myoblasts scattered in loose fibrous connective tissue. By immunohistochemistry, they showed diffuse and strong positivity for desmin, MSA and myoglobin with variable expression of myogenin. A case of intermediate type also stained for α-smooth muscle actin. Follow up data (2 months ~ 17 years) showed local recurrence in one patient 6 months after surgery.</p><p><b>CONCLUSIONS</b>Rhabdomyoma is a distinctively rare benign mesenchymal tumor showing skeletal muscle differentiation, which may occassionally recur if incompletely excised. Familiarity with its clinical and morphological variants is essential to avoid misdiagnosing this benign lesion as embryonal rhabdomyosarcoma.</p>

Effect of over-expressed miR-155 on inhibiting C2C12 myogenic differentiation / 生物工程学报

To clarify the function and molecular mechanism of miR-155 in myogenic differentiation of C2C12, we constructed adenovirus over-expression vector of miR-155, then C2C12 cells were infected by adenovirus and induced myogenic differentiation. First, we observed the morphology of C2C12 after differentiation. Then the mRNA and protein expressions of myogenic markers (MyoD, MyoG and MyHC) were detected by qPCR and western blotting. Subsequently, the dual luciferase reporter gene assay was carried out to validate putative target gene (TCF4) of miR-155. Meanwhile, mRNA level of TCF4 was analyzed after over-expressing miR-155. The results show that over-expressed miR-155 reduced myotubes formation. Moreover, the mRNA and protein expression of MyoG and MyHC decreased significantly (P < 0.01). Further research demonstrated miR-155 bound the one (4532-4538) of three putative sites (1487-1493,1516-1522, 4532-4583) of TCF4 by luciferase reporter gene assay and the mRNA level of TCF4 decreased notably (P < 0.05). The data suggest that miR-155 inhibited myogenic differentiation of C2C12 through targeted TCF4.

Os efeitos do laser de baixa potência no processo de reparo muscular após criolesão em ratos / The effects of low-level laser therapy on muscle healing process after cryolesion

O objetivo deste estudo foi verificar os efeitos da laserterapia de baixa potência no comprimento de onda ?=780nm entre diferentes períodos de tratamento 7, 14 e 21 dias e verificar a dose (10J/cm2 ou 50J/cm2) que promove melhor reparo muscular através das análises histopatológicas e imunohistoquímicas. Foram utilizados 54 ratos machos divididos em 3 grupos: GC: grupo controle (criolesão, sem tratamento); G10: criolesão do músculo tibial anterior (TA) e tratados com laser dose 10J/cm² e G50: criolesão do músculo TA e tratados com laser dose 50J/cm² que foram subdivididos em 3 subgrupos (n=6): 7, 14 e 21 dias de tratamento. Os achados histopatológicos revelaram maior organização das fibras musculares dos grupos tratados com laser 10J/cm² e 50J/cm² durante os períodos 7 e 14 dias em relação ao grupo controle; no período 21 dias os grupos apresentaram semelhanças na reparação tecidual. Em relação à área da lesão os grupos tratados com laser 10J/cm² e 50J/cm² durante 7 dias obtiveram diminuição significativa (p ? 0.05) da área da lesão em relação ao grupo controle, sendo que os grupos 14 e 21 dias não apresentaram diferenças significativas entre eles. Na contagem dos vasos o grupo tratado com laser 10J/cm² no 14° dia apresentou aumento dos vasos em relação ao grupo tratado com dose 50J/cm², mas não em relação ao grupo controle. Nos tempos de 7 e 21 dias os grupos não apresentaram diferença significativa entre si. Com relação às análises imunohistoquímicas da myoD no período de 7 dias os grupos tratados com laser 10J/cm² e 50J/cm² apresentaram maior imunomarcação comparada com o grupo controle, no período 14 e 21 dias a imunomarcação estava ausente.

The objective of this study was to assess the effects of 780nm low-level laser therapy at different periods of 7, 14 and 21 days after cryolesion, including the dose (10 or 50J/cm2) to promote a better muscle repair evidenced by histopathological and immumohistochemical analyses. Fifty-four male rats were divided into three groups: injured control group (CG) - injured animals without any treatment; injured 780nm laser treated group, at 10 J/cm² (G10) and injured 780nm laser treated group, at 50 J/cm² (G50). Each group was divided into 3 subgroups (n=6): 7, 14 and 21 days post-injury. Histopathological findings revealed better-organized muscle fibers in the G10 and G50 during the periods of 7 and 14 days compared to CG. The G10 and G50 during 7 days showed a significant reduction (p? 0.05) of lesion area compared to CG, without differences between groups treated for 14 and 21 days. The G10 showed an increase of the amount of vessels after 14 days compared to the G50, but not in relation to controls. With regard to the immumohistochemical analyses of the MyoD factor, The G10 and G50 during 7 days showed higher concentrations of immunomarkers than controls.

Clinicopathologic features of pleomorphic rhabdomyosarcoma / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate the clinicopathologic characteristics, differential diagnosis and biologic behaviors of pleomorphic rhabdomyosarcoma (PRMS).</p><p><b>METHODS</b>The clinical findings, pathological features and immunophenotypes were reviewed in 44 cases of PRMS (encountered during the period from 2005 to 2012). The clinical outcome was analyzed.</p><p><b>RESULTS</b>There were 33 males and 11 females with age ranging from 2 to 85 years (mean, 51 years; median, 55 years). Of 44 tumors, 22 occurred in the extremities (50.0%), 16 in the trunk (36.4%), 5 in the internal organs (11.4%), and 1 in the head and neck (2.2%). Histologically, 40 tumors showed features of pleomorphic sarcoma with striking resemblance to undifferentiated pleomorphic sarcoma (UPS)/malignant fibrous histiocytoma(MFH). However, variable amount of pleomorphic rhabdomyoblasts (PRMB) were identified in most cases. The remaining 4 tumors were composed predominantly of fascicles of spindle cells with interspersed PRMBs. Immunohistiochemically, tumor cells showed diffuse staining of desmin (41/41,100%), with variable expression of myogenin (18/32, 56.3%), MyoD1 (10/21, 47.6%) and MSA (21/29, 72.4%), whereas α-SMA was negative in most cases. Follow-up data (range, 2 to 51 months) available in 29 cases showed 12 patients were alive with unresectable or recurrent disease and 17 patients were alive with no evidence of disease. The median disease-free and overall survivals was 6.0 months (mean, 9.1 months) and 8.0 months (mean, 11.2 months) respectively. Thirteen patients (44.8%) exhibited progression of disease with recurrence in 4 cases and metastasis in 9 cases. The median interval to progression was 6.0 months (mean, 5.9 months).</p><p><b>CONCLUSIONS</b>The presence of pleomorphic cells with strong eosinphilic cytoplasm in a pleomorphic sarcoma is suggestive of a PRMS. Diffuse, strong expression of desmin and negative staining for α-SMA further facilitate the diagnosis of PRMS and its differential diagnosis from pleomorphic leiomyosarcoma. Although PRMS may affect children or adolescents, it should be cautious not to misdiagnose anaplastic rhabdomyosarcoma as PRMS. PRMS is a high-grade sarcoma with a poor prognosis.</p>

Expression of Thyroid Stimulating Hormone Receptor mRNA in Mouse C2C12 Skeletal Muscle Cells

BACKGROUND: We analyzed whether thyroid stimulating hormone receptor (TSH-R) is expressed in a skeletal muscle cell line and if TSH has influence on the differentiation of muscle cells or on the determination of muscle fiber types. METHODS: TSH-R gene expression was detected with nested real-time polymerase chain reaction (RT-PCR) in C2C12, a mouse skeletal muscle cell line. The effect of TSH on myotube differentiation was assessed by microscopic examination of myotube formation and through the measurement of expression of muscle differentiation markers, i.e., myogenin and myoD, and muscle type-specific genes, i.e., MyHC1, MyHC2a, and MyHC2b, with quantitative RT-PCR before and after incubation of C2C12 myotube with TSH. RESULTS: TSH-R was expressed in the mouse skeletal muscle cell line. However, treatment with TSH had little effect on the differentiation of muscle cells, although the expression of the muscle differention marker myogenin was significantly increased after TSH treatment. Treatment of TSH did not affect the expression of muscle type-specific genes. CONCLUSION: TSH-R is expressed in a mouse skeletal muscle cell line, but the role of TSH receptor signaling in skeletal muscle needs further investigation.

Establishment and pathologic analysis of imatinib-resistant gastrointestinal stromal tumor xenografts / 中华病理学杂志

<p><b>OBJECTIVE</b>To establish and characterize imatinib-resistant gastrointestinal stromal tumor (GIST) xenografts. Further provided an ideal experimental platform through the imatinib-resistant GIST xenografts to investigate the mechanism of resistance to imatinib.</p><p><b>METHODS</b>Imatinib-resistant GIST cells were injected under the skin of athymic nude mice to establish animal models of human imatinib-resistant GIST. The molecular and histopathologic features of GIST xenografts were also analysed and compared with their counterpart of cell lines.</p><p><b>RESULTS</b>The xenograft tumor models had been established by subcutaneously injection of GIST cells into nude mice. Immunohistochemistry results showed CD117 expression was positive in GIST-PR2 xenograft tumor, but negative in GIST-R. In GIST-PR1, tumor areas showing rhabdomyoblastic differentiation were presented next to areas with classic GIST morphology. The rhabdomyoblastic component demonstrated consistently positivity for desmin and myogenin, whereas CD117 was completely negative. The mutation profiles of these xenograft tumors were the same as their counterpart of cell lines.</p><p><b>CONCLUSIONS</b>Human GIST xenografts with mutation in c-kit have been established from imatinib-resistant GIST lines. Those models will enable further studies on mechanisms of resistance, combination therapies and allow testing of novel targeted therapies.</p>

Rhabdomyosarcoma in middle to old-aged patients: analysis of clinicopathological features and prognosis in 76 cases / 中华肿瘤杂志

<p><b>OBJECTIVE</b>Albeit rare, rhabdomyosarcoma (RMS) may occur in middle to old-aged adults. The purpose of this study was to investigate the clinicopathological characteristics and prognosis of RMS in patients ≥ 40 years of age.</p><p><b>METHODS</b>The clinical, pathological and immunohistochemical profiles of the 76 cases were reviewed, and the outcomes were analyzed.</p><p><b>RESULTS</b>There were 46 males and 30 females with a median age of 55 years. Sixty cases occurred in somatic soft tissues, including extremities (n = 25), head and neck (n = 19) and trunk (n = 16). Sixteen developed in the internal organs with predilection for the urogenital tract. Histologically, 38 cases (50.0%) were of embryonal RMS (ERMS) subtype, 29 cases (38.2%) of pleomorphic RMS (PRMS), 7 cases (9.2%) of poorly-differentiated RMS (PdRMS), and 2 cases (2.6%) of alveolar RMS (ARMS). Immunohistiochemically, the tumor cells showed diffuse staining of desmin (68/68, 100%), with a variable expression of myogenin (30/43, 69.8%), MyoD1 (33/51, 64.7%) and MSA (29/40, 72.5%). The therapy data available in 54 cases showed that three inoperable cases were treated with chemotherapy and radiotherapy, 51 cases underwent local excision, including 10 cases with chemotherapy, 9 cases with radiotherapy, 8 cases with chemotherapy and radiotherapy after surgery, and the remaining 24 cases were not administrered with postoperative adjuvant therapy. The follow-up data available in 54 cases showed that 22 patients were alive with unresectable or recurrent/disease and 32 patients were alive with no evidence of disease. The median disease-free and overall survivals were 6.0 months and 7.0 months, respectively. Twenty-seven patients exhibited progression of disease with recurrence in 8 cases and metastasis in 19 cases. The median interval to progression was 6.0 months.</p><p><b>CONCLUSIONS</b>The most common subtypes of RMS in middle to old aged patients are ERMS and PRMS. In general, Rhabdomyosarcomas of middle to old aged patients shows a highly aggressive behavior. Patients may benefit from multi-disciplinary therapy.</p>

Embryonal rhabdomyosarcoma of the adult soft palate.

Embryonal rhabdomyosarcoma is the most common soft tissue sarcoma in children. We report a rare case of embryonal rhabdomyosarcoma of the soft palate in a 32-year-old Caucasian female. Detailed histology of the tumor is described. Positive staining with desmin, myogenin and myoD1 confirmed the tumor to be embryonal rhabdomyosarcoma. A genetic association between rhabdomyosarcoma, polycystic ovary syndrome and the FEM1A gene on the human chromosome is speculated upon.

A comparison of the myogenic characteristics between stem cell antigen-(1+) and stem cell antigen-(1-) cells derived from skeletal muscle / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To probe into the function of stem cell antigen-1 (Sca-1) in cell proliferation and differentiation.</p><p><b>METHODS</b>Sca-(1+) and Sca-(1-) muscle derived cells were separated from C57BU6 mice by fluorescence-activated cell sorting and then cultured in vitro. After 5 days cells proliferative curve were drawn according CCK-8 experimental results. Western blot also were done to detect Sca(-1), MyoD and Myogenin expression in cultured Sca(-1+) and Sca-(1-) muscle derived cells.</p><p><b>RESULTS</b>The difference of the proliferative curve of Sca-(1+) and Sca-(1-) muscle derived cells cultured 3 days in vitro was not apparent, but Sca-(1-) muscle derived cells had a accelerated division rate in the follow days compared to the Sca-(1+) muscle derived cells. Sca-1 expression in both cells was not obvious. MyoD and Myogenin expression were stronger in Sca-(1+) than Sca-(1-) muscle derived cells.</p><p><b>CONCLUSION</b>Sca-1 expression in muscle derived cells takes a period of time that related to the beginning and ending of the cell cycle.</p>

Adult prostate sarcoma: a clinicopathologic study of 15 cases / 中华病理学杂志

<p><b>OBJECTIVE</b>To clarify the clinical and morphological features of adult prostate sarcoma (APS) and to further improve the knowledge and diagnostic accuracy for APS.</p><p><b>METHODS</b>Fifteen cases of APS were observed and analyzed on the clinical symptom, pathological features, treatment and prognosis.</p><p><b>RESULTS</b>Age of onset ranged from 22 to 77 years (mean 46.3 years). The majority of cases were presented with dysuresia. By digital rectal examination and imaging of the prostate, APS was often identified as a large tumor mass. There were 6 cases of leiomyosarcomas, 6 embryonal rhabdomyosarcomas, and 3 fibrosarcomas in this series. Follow-up data were available for 12 cases: 7 cases died of the disease between 9 days and 360 days after surgery. Among 5 survived patients, 3 cases had recurrence after 2 to 24 months follow-up.</p><p><b>CONCLUSIONS</b>APS is a rare tumor that typically has clinical features: earlier age of onset, fast-appeared urinary tract symptoms, significant mass effects, and poor outcome. Level of prostate specific antigen (PSA) is usually normal or lower. Final diagnosis relies on the features of histology and immunohistochemistry expression profile.</p>