Most residues on the floor of the antigen binding site of the class I MHC molecule H-2Kd influence peptide presentation.

A panel of 15 single alanine substitutions on the floor of the peptide binding groove of the murine class I histocompatibility molecule H-2Kd has been analyzed. All but two mutant molecules were expressed on the cell surface, and were tested for peptide binding and presentation to specific cytotoxic T lymphocytes. Eleven out of 13 mutant molecules appeared to be functionally altered. Five of the substituted residues were involved in the presentation of all peptides tested. Three participated in the presentation of certain peptides but not others. Three other residues participated in epitope formation through indirect interactions. Only two mutations had no detectable effect.

Myostatin augments muscle-specific ring finger protein-1 expression through an NF-kB independent mechanism in SMAD3 null muscle.

Smad (Sma and Mad-related protein) 2/3 are downstream signaling molecules for TGF-β and myostatin (Mstn). Recently, Mstn was shown to induce reactive oxygen species (ROS) in skeletal muscle via canonical Smad3, nuclear factor-κB, and TNF-α pathway. However, mice lacking Smad3 display skeletal muscle atrophy due to increased Mstn levels. Hence, our aims were first to investigate whether Mstn induced muscle atrophy in Smad3(-/-) mice by increasing ROS and second to delineate Smad3-independent signaling mechanism for Mstn-induced ROS. Herein we show that Smad3(-/-) mice have increased ROS levels in skeletal muscle, and inactivation of Mstn in these mice partially ablates the oxidative stress. Furthermore, ROS induction by Mstn in Smad3(-/-) muscle was not via nuclear factor-κB (p65) signaling but due to activated p38, ERK MAPK signaling and enhanced IL-6 levels. Consequently, TNF-α, nicotinamide adenine dinucleotide phosphate oxidase, and xanthine oxidase levels were up-regulated, which led to an increase in ROS production in Smad3(-/-) skeletal muscle. The exaggerated ROS in the Smad3(-/-) muscle potentiated binding of C/EBP homology protein transcription factor to MuRF1 promoter, resulting in enhanced MuRF1 levels leading to muscle atrophy.

Latissimus dorsi muscle-flap over Gore-Tex patch for coverage of large thoracic defects in paediatric Ewing sarcoma.

Primary rib involvement accounts for 16% of paediatric Ewing sarcoma (ES). Neo-adjuvant chemotherapy and surgical tumor resection may leave large thoracic wall defects requiring complex reconstruction in a growing individual. We report our experience in three children aged 3, 10, and 12 years, in whom single-stage resection and reconstruction were performed using a Gore-Tex Dualmesh patch, covered by a latissimus dorsi rotation flap harvested in continuity with the thoracolumbar fascia. The youngest patient also had a vertical expandable prosthetic titanium rib (VEPTR) anchored to help prevent subsequent scoliosis throughout growth.

Wide-pulse-high-frequency neuromuscular stimulation of triceps surae induces greater muscle fatigue compared with conventional stimulation.

We compared the extent and origin of muscle fatigue induced by short-pulse-low-frequency [conventional (CONV)] and wide-pulse-high-frequency (WPHF) neuromuscular electrical stimulation. We expected CONV contractions to mainly originate from depolarization of axonal terminal branches (spatially determined muscle fiber recruitment) and WPHF contractions to be partly produced via a central pathway (motor unit recruitment according to size principle). Greater neuromuscular fatigue was, therefore, expected following CONV compared with WPHF. Fourteen healthy subjects underwent 20 WPHF (1 ms-100 Hz) and CONV (50 μs-25 Hz) evoked isometric triceps surae contractions (work/rest periods 20:40 s) at an initial target of 10% of maximal voluntary contraction (MVC) force. Force-time integral of the 20 evoked contractions (FTI) was used as main index of muscle fatigue; MVC force loss was also quantified. Central and peripheral fatigue were assessed by voluntary activation level and paired stimulation amplitudes, respectively. FTI in WPHF was significantly lower than in CONV (21,717 ± 11,541 vs. 37,958 ± 9,898 N·s P<0,001). The reductions in MVC force (WPHF: -7.0 ± 2.7%; CONV: -6.2 ± 2.5%; P < 0.01) and paired stimulation amplitude (WPHF: -8.0 ± 4.0%; CONV: -7.4 ± 6.1%; P < 0.001) were similar between conditions, whereas no change was observed for voluntary activation level (P > 0.05). Overall, our results showed a different motor unit recruitment pattern between the two neuromuscular electrical stimulation modalities with a lower FTI indicating greater muscle fatigue for WPHF, possibly limiting the presumed benefits for rehabilitation programs.

Actions of β2-adrenoceptor agonist drug on human soleus muscle contraction.

PURPOSE: The effects of β(2)-agonists on human skeletal muscle contractile properties, particularly on slow fibers, are unclear. Moreover, it remains to be ascertained whether central motor drive (CMD) during voluntary contractions could counter for eventual contractile alterations induced by β(2)-agonists. This study investigated central and peripheral neuromuscular adjustments induced by β(2)-agonist terbutaline on a predominantly slow human muscle, the soleus. METHODS: Ten recreationally active men ingested either a single dose of 8 mg of terbutaline or placebo in a randomized double-blind order (two experimental sessions). Isometric plantarflexion torque was measured during single and tetanic (10 and 100 Hz) stimulations as well as during submaximal and maximal voluntary contractions (MVC). Twitch peak torque and half-relaxation time were calculated. CMD was estimated via soleus electromyographic recordings obtained during voluntary contractions performed at approximately 50% MVC. RESULTS: MVC and twitch peak torque were not modified by terbutaline. Twitch half-relaxation time was 28% shorter after terbutaline administration compared with placebo (P < 0.001). Tetanic torques at 10 and 100 Hz were significantly lower after terbutaline intake compared with placebo (-40% and -24% respectively, P < 0.001). Despite comparable torque of submaximal voluntary contractions in the two conditions, CMD was 7% higher after terbutaline ingestion compared with placebo (P < 0.01). CONCLUSION: These results provide evidence that terbutaline modulates the contractility of the slow soleus muscle and suggest that the increased CMD during submaximal contractions may be viewed as a compensatory adjustment of the central nervous system to counter the weakening action induced by terbutaline on the contractile function of slow muscle fibers.

Lack of Smad3 signaling leads to impaired skeletal muscle regeneration.

Smad3 is a key intracellular signaling mediator for both transforming growth factor-β and myostatin, two major regulators of skeletal muscle growth. Previous published work has revealed pronounced muscle atrophy together with impaired satellite cell functionality in Smad3-null muscles. In the present study, we have further validated a role for Smad3 signaling in skeletal muscle regeneration. Here, we show that Smad3-null mice had incomplete recovery of muscle weight and myofiber size after muscle injury. Histological/immunohistochemical analysis suggested impaired inflammatory response and reduced number of activated myoblasts during the early stages of muscle regeneration in the tibialis anterior muscle of Smad3-null mice. Nascent myofibers formed after muscle injury were also reduced in number. Moreover, Smad3-null regenerated muscle had decreased oxidative enzyme activity and impaired mitochondrial biogenesis, evident by the downregulation of the gene encoding mitochondrial transcription factor A, a master regulator of mitochondrial biogenesis. Consistent with known Smad3 function, reduced fibrotic tissue formation was also seen in regenerated Smad3-null muscle. In conclusion, Smad3 deficiency leads to impaired muscle regeneration, which underscores an essential role of Smad3 in postnatal myogenesis. Given the negative role of myostatin during muscle regeneration, the increased expression of myostatin observed in Smad3-null muscle may contribute to the regeneration defects.

Avaliacao dos resultados cirurgicos com a tecnica da resseccao do musculo de Muller-conjuntiva no tratamento da blefaroptose. [Evaluation of the surgery results of Muller's muscle-conjunctival resection in the treatment of blepharoptosis]

OBJECTIVE: To evaluate the results of Muller's muscle-conjunctival resection for correction of blepharoptosis and to discuss the advantages of this procedure. METHODS: 38 patients (39 eyelids) were submitted to Muller's muscle-conjunctival resection. Blepharoptosis varied from 1.0 mm to 3.0 mm (mean: 2.0 mm). The amount of eyelid elevation produced by phenylephrine guided the amount of tissue to be resected. RESULT: 33 eyelids (85%) treated with this procedure were cosmetically acceptable. CONCLUSIONS: Muller's muscle-conjunctival resection procedure is a relatively simple technique for blepharoptosis, with good levator function and positive 10% phenylephrine test. The advantages are: preservation of tarsus and predictable results.

Thyroid hormone enhances transected axonal regeneration and muscle reinnervation following rat sciatic nerve injury.

Improvement of nerve regeneration and functional recovery following nerve injury is a challenging problem in clinical research. We have already shown that following rat sciatic nerve transection, the local administration of triiodothyronine (T3) significantly increased the number and the myelination of regenerated axons. Functional recovery is a sum of the number of regenerated axons and reinnervation of denervated peripheral targets. In the present study, we investigated whether the increased number of regenerated axons by T3-treatment is linked to improved reinnervation of hind limb muscles. After transection of rat sciatic nerves, silicone or biodegradable nerve guides were implanted and filled with either T3 or phosphate buffer solution (PBS). Neuromuscular junctions (NMJs) were analyzed on gastrocnemius and plantar muscle sections stained with rhodamine alpha-bungarotoxin and neurofilament antibody. Four weeks after surgery, most end-plates (EPs) of operated limbs were still denervated and no effect of T3 on muscle reinnervation was detected at this stage of nerve repair. In contrast, after 14 weeks of nerve regeneration, T3 clearly enhanced the reinnervation of gastrocnemius and plantar EPs, demonstrated by significantly higher recovery of size and shape complexity of reinnervated EPs and also by increased acetylcholine receptor (AChRs) density on post synaptic membranes compared to PBS-treated EPs. The stimulating effect of T3 on EP reinnervation is confirmed by a higher index of compound muscle action potentials recorded in gastrocnemius muscles. In conclusion, our results provide for the first time strong evidence that T3 enhances the restoration of NMJ structure and improves synaptic transmission.

Fluoreszenzdiagnostik bei Patienten mit nicht muskelinvasivem Harnblasenkarzinom: Ergebnisse einer Metaanalyse [Fluorescence diagnosis in patients with non-muscle invasive bladder cancer: results of a metaanalysis]

Purpose: Heterogeneous results of single studies with photodynamic diagnosis (PDD) in bladder cancer have been reported. A metaanalysis of prospective studies has now been performed. Material and Methods: The effect of PDD in addition to WLC on a) the diagnosis and b) the therapeutic outcome of primary or recurrent non-muscle invasive bladder cancer (NMIBC) investigated by cystoscopy or transurethral resection was analysed. An electronic database search was performed. Trials were included if they prospectively compared WLC with PDD in bladder cancer. Primary endpoints were additional detection rate, residual tumour at second resection and recurrence-free survival. Results: Significantly more tumour-positive patients were detected with PDD in all patients with non-muscle invasive tumours (= 20%) [95% confidence interval (CI): 8 to 35%] and in CIS patients (= 39%) (CI: 23 to 57%). Residual tumour was significantly less often found after PDD (odds ratio 0.28, CI: 0.15 to 0.52, p<0.0001). Recurrence-free survival was significantly higher at 12 and 24months in the PDD groups than in WLC only groups. Conclusions: More bladder tumour-positive patients are detected by PDD. Best results were found in CIS patients. Diagnosis with PDD results in a more complete resection and a longer recurrence-free survival.

Hexyl Aminolevulinate-Guided Fluorescence Cystoscopy in the Diagnosis and Follow-up of Patients with Non-Muscle-invasive Bladder Cancer: A Critical Review of the Current Literature.

CONTEXT: Controversy exists regarding the therapeutic benefit and cost effectiveness of photodynamic diagnosis (PDD) with 5-aminolevulinic acid (5-ALA) or hexyl aminolevulinate (HAL) in addition to white-light cystoscopy (WLC) in the management of non-muscle-invasive bladder cancer (NMIBC). OBJECTIVE: To systematically evaluate evidence regarding the therapeutic benefits and economic considerations of PDD in NMIBC detection and treatment. EVIDENCE ACQUISITION: We performed a critical review of PubMed/Medline, Embase, and the Cochrane Library in October 2012 according to the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) statement. Identified reports were reviewed according to the Consolidated Standards of Reporting Trials (CONSORT) and Standards for the Reporting of Diagnostic Accuracy Studies (STARD) criteria. Forty-four publications were selected for inclusion in this analysis. EVIDENCE SYNTHESIS: Included reports used 5-ALA (in 26 studies), HAL (15 studies), or both (three studies) as photosensitising agents. PDD increased the detection of both papillary tumours (by 7-29%) and flat carcinoma in situ (CIS; by 25-30%) and reduced the rate of residual tumours after transurethral resection of bladder tumour (TURBT; by an average of 20%) compared to WLC alone. Superior recurrence-free survival (RFS) rates and prolonged RFS intervals were reported for PDD, compared to WLC in most studies. PDD did not appear to reduce disease progression. Our findings are limited by tumour heterogeneity and a lack of NMIBC risk stratification in many reports or adjustment for intravesical therapy use in most studies. Although cost effectiveness has been demonstrated for 5-ALA, it has not been studied for HAL. CONCLUSIONS: Moderately strong evidence exists that PDD improves tumour detection and reduces residual disease after TURBT compared with WLC. This has been shown to improve RFS but not progression to more advanced disease. Further work to evaluate cost effectiveness of PDD is required.

Isolated cerebral metastasis of a triceps muscle leiomyosarcoma: A case report.

Abstract Leiomyosarcomas are rare malignant neoplasms. Intracranial metastases of this tumour are even less frequently observed and have mostly been described from uterine leiomyosarcomas. In this article, we describe the case of a single right frontal subcortical cerebral metastasis in a patient with a right triceps muscle leiomyosarcoma. A right-sided frontal craniotomy with macroscopically complete tumour removal was performed, followed by combined radio-chemotherapy. The patient died 10 months after the initial diagnosis of the intracranial metastasis due to systemic tumour progression, without any evidence of intracranial recurrence.

Transcript profiling suggests that differential metabolic adaptation of mice to a high fat diet is associated with changes in liver to muscle lipid fluxes.

Genetically homogenous C57Bl/6 mice display differential metabolic adaptation when fed a high fat diet for 9 months. Most become obese and diabetic, but a significant fraction remains lean and diabetic or lean and non-diabetic. Here, we performed microarray analysis of "metabolic" transcripts expressed in liver and hindlimb muscles to evaluate: (i) whether expressed transcript patterns could indicate changes in metabolic pathways associated with the different phenotypes, (ii) how these changes differed from the early metabolic adaptation to short term high fat feeding, and (iii) whether gene classifiers could be established that were characteristic of each metabolic phenotype. Our data indicate that obesity/diabetes was associated with preserved hepatic lipogenic gene expression and increased plasma levels of very low density lipoprotein and, in muscle, with an increase in lipoprotein lipase gene expression. This suggests increased muscle fatty acid uptake, which may favor insulin resistance. In contrast, the lean mice showed a strong reduction in the expression of hepatic lipogenic genes, in particular of Scd-1, a gene linked to sensitivity to diet-induced obesity; the lean and non-diabetic mice presented an additional increased expression of eNos in liver. After 1 week of high fat feeding the liver gene expression pattern was distinct from that seen at 9 months in any of the three mouse groups, thus indicating progressive establishment of the different phenotypes. Strikingly, development of the obese phenotype involved re-expression of Scd-1 and other lipogenic genes. Finally, gene classifiers could be established that were characteristic of each metabolic phenotype. Together, these data suggest that epigenetic mechanisms influence gene expression patterns and metabolic fates.

Regenerative cell injection in denervated muscle reduces atrophy and enhances recovery following nerve repair.

INTRODUCTION: Functional muscle recovery after peripheral nerve injury is far from optimal, partly due to atrophy of the muscle arising from prolonged denervation. We hypothesized that injecting regenerative cells into denervated muscle would reduce this atrophy. METHODS: A rat sciatic nerve lesion was performed, and Schwann cells or adipose-derived stem cells, untreated or induced to a "Schwann-cell-like" phenotype (dASC), were injected into the gastrocnemius muscle. Nerves were either repaired immediately or capped to prevent muscle reinnervation. One month later, functionality was measured using a walking track test, and muscle atrophy was assessed by examining muscle weight and histology. RESULTS: Schwann cells and dASC groups showed significantly better scores on functional tests when compared with injections of growth medium alone. Muscle weight and histology were also significantly improved in these groups. CONCLUSION: Cell injections may reduce muscle atrophy and could benefit nerve injury patients.