Quantitative ultrasound of the tongue and submental muscles in children and young adults

Introduction: The purpose of this study was to assess the feasibility of quantitative muscle ultrasound (QMUS) to visualize oral muscles and to establish normative data for muscle thickness and echo intensity of submental and tongue muscles in healthy children and young adults. The data were compared with those of 5 patients with Duchenne muscular dystrophy (DMD). Methods: Ultrasound images from the suprahyoid region and from the surface of the tongue were made in 53 healthy subjects aged 5 to 30 years. Results: All measurements were feasible in all subjects and patients with good reproducibility except for the mylohyoid muscle. Muscle thickness depended on height, and echo intensity depended on weight. Our findings suggest gradual involvement of oral muscles in DMD. Conclusions: QMUS in oral muscles is feasible in healthy children, adults and patients with DMD. These data show that it is possible to differentiate between healthy persons and patients with DMD. Muscle Nerve 46:31–37, 2012     

Quantitative muscle ultrasonography in the follow‐up of juvenile dermatomyositis

Introduction: We explored the use of quantitative muscle ultrasonography (QMUS) for follow‐up of juvenile dermatomyositis (JDM). Methods: Seven JDM patients were evaluated at diagnosis and 1, 3, 6, 12, and 24 months using the Childhood Myositis Assessment Scale (CMAS) and QMUS. Muscle thickness (MT) and quantitative muscle echo intensity (EI) were assessed with QMUS in 4 muscles. Results: Six patients experienced a monocyclic course. At diagnosis EI was slightly increased, and MT was relatively normal. After start of treatment MT first decreased and EI increased, with normalization of EI within 6–12 months (n = 4). One patient had higher EIs at diagnosis and slower normalization, indicating fibrosis, despite early normalization of CMAS. One patient experienced a chronic course, with high EIs and atrophy during follow‐up. Conclusions: QMUS can provide additional information for follow‐up of JDM regarding disease severity and residual muscle damage, particularly after normalization of CMAS. Muscle Nerve 52: 540–546, 2015     

Quantitative muscle ultrasound versus quantitative magnetic resonance imaging in facioscapulohumeral dystrophy

Introduction: Ultrasound and magnetic resonance imaging (MRI) are non‐invasive methods that can be performed repeatedly and without discomfort. In the assessment of neuromuscular disorders it is unknown if they provide complementary information. In this study we tested this for patients with facioscapulohumeral muscular dystrophy (FSHD). Methods: We performed quantitative muscle ultrasound (QMUS) and quantitative MRI (QMRI) of the legs in 5 men with FSHD. Results: The correlation between QMUS‐determined z‐scores and QMRI‐determined muscle fraction and T1 signal intensity (SI) was very high. QMUS had a wider dynamic range than QMRI, whereas QMRI could detect inhomogeneous distribution of pathology over the length of the muscles. Conclusions: Both QMUS and QMRI are well suited for imaging muscular dystrophy. The wider dynamic range of QMUS can be advantageous in the follow‐up of advanced disease stages, whereas QMRI seems preferable in pathologies such as FSHD that affect deep muscle layers and show inhomogeneous abnormality distributions. Muscle Nerve 50: 968–975, 2014     

Ultrasound imaging of muscles in Duchenne muscular dystrophy

The ultrasound imaging of quadriceps, gastrocnemius and soleus muscles was performed in 30 patients with Duchenne muscular dystrophy (DMD) and 16 control subjects. In controls, the skeletal muscle itself was scarcely echogenic. However, bone surface and fascia were clearly echogenic. The transverse scan of muscle in all DMD patients showed an increased echogenicity, which made the echo from bone or fascia less intense. The abnormal muscle echo was graded according to Heckmatt et al. From the quantitative aspect, there was a significant correlation between disability scale of DMD patients and abnormal echogenicity of the quadriceps muscle. A similar correlation was also observed between results of manual muscle testing the ultrasound imaging. The soleus muscle was usually less abnormal than the gastrocnemius in the ultrasound imaging. Thus, the ultrasound imaging seemed to provide an important information for the clinical assessment of DMD patients.     

Muscle ultrasound in neuromuscular disorders

Muscle ultrasound is a useful tool in the diagnosis of neuromuscular disorders, as these disorders result in muscle atrophy and intramuscular fibrosis and fatty infiltration, which can be visualized with ultrasound. Several prospective studies have reported high sensitivities and specificities in the detection of neuromuscular disorders. Although not investigated in large series of patients, different neuromuscular disorders tend to show specific changes on muscle ultrasound, which can be helpful in differential diagnosis. For example, Duchenne muscular dystrophy results in a severe, homogeneous increase of muscle echo intensity with normal muscle thickness, whereas spinal muscular atrophy shows an inhomogeneous increase of echo intensity with severe atrophy. A major advantage of muscle ultrasound, compared to other imaging techniques, is its ability to visualize muscle movements, such as muscle contractions and fasciculations. This study reviews the possibilities and limitations of ultrasound in muscle imaging and its value as a diagnostic tool in neuromuscular disorders.     

Malignant hyperthermia susceptibility in X-linked muscle dystrophies

To evaluate malignant hyperthermia (MH) susceptibility in X-linked muscular dystrophies, halothane and caffeine contracture tests were performed on muscle fiber bundles from five patients with Duchenne muscular dystrophy (DMD) and two patients with Becker muscular dystrophy (BMD). Two DMD patients and one BMD patient had positive contracture tests. Since a positive contracture test is currently the best indicator of anesthetic susceptibility in the MH population, and episodes of MH in dystrophic patients have been reported, patients with DMD and BMD may be at risk for developing similar anesthetic complications. Awareness of this potential anesthetic risk is of importance because orthopedic interventions are increasingly more common in these patients.     

Quantitative muscle ultrasound and quadriceps strength in patients with post‐polio syndrome

Introduction: We investigated whether muscle ultrasound can distinguish muscles affected by post‐polio syndrome (PPS) from healthy muscles and whether severity of ultrasound abnormalities is associated with muscle strength. Methods: Echo intensity, muscle thickness, and isometric strength of the quadriceps muscles were measured in 48 patients with PPS and 12 healthy controls. Results: Patients with PPS had significantly higher echo intensity and lower muscle thickness than healthy controls. In patients, both echo intensity and muscle thickness were associated independently with muscle strength. A combined measure of echo intensity and muscle thickness was more strongly related to muscle strength than either parameter alone. Conclusions: Quantitative ultrasound distinguishes healthy muscles from those affected by PPS, and measures of muscle quality and quantity are associated with muscle strength. Hence, ultrasound could be a useful tool for assessing disease severity and monitoring changes resulting from disease progression or clinical intervention in patients with PPS. Muscle Nerve 51 : 24–29, 2015     

Quantitative ultrasonography of facial muscles in patients with chronic facial palsy

Introduction: In this study we introduce quantitative facial muscle ultrasound as a diagnostic tool for patients with chronic unilateral facial palsy. Methods: Muscle area, thickness, and echo intensity of 6 facial muscles (frontalis, orbicularis oculi, orbicularis oris, depressor anguli oris, depressor labii inferioris, and mentalis) and of 2 chewing muscles (temporalis and masseter, as controls) were measured in 20 patients with chronic facial palsy. Results: Aside from 1, all facial muscles were significantly smaller on the paralyzed side. With exception of frontalis and orbicularis oculi muscles, all other facial muscles showed significantly higher echo intensity on the affected side. Muscle size and echo intensity of the chewing muscles showed no side‐to‐side asymmetry. Conclusions: Quantitative ultrasound of facial muscles helps to better characterize their status in patients with chronic facial palsy in the phase of denervation and during regeneration. Muscle Nerve 50 : 358–365, 2014     

Concanavalin a binding of the cell surface of Duchenne muscle in vitro

Ultrastructural examination of concanavalin A (Con A) binding sites in cultured skeletal muscle from six patients with Duchenne muscular dystrophy (DMD) revealed no abnormalities at the cell surface when compared to normal cultured skeletal muscle. Reaction product at the cell surface appeared regular and continuous in both normal and dystrophic cultured muscle cells. These findings indicate that the abnormalities of Con A surface binding found in biopsied muscle of DMD are not present in aneurally cultured dystrophic muscle cells.     

Expression and localization of protein inhibitor of neuronal nitric oxide synthase in Duchenne muscular dystrophy.

In skeletal muscle fibers, nitric oxide is synthesized by neuronal nitric oxide synthase (nNOS), which normally associates with the dystrophin complex in close proximity to the sarcolemma. Many reports have documented that very low levels of nNOS protein exist in muscle fibers of Duchenne muscular dystrophy (DMD) patients. In this study we investigated the functional significance of PIN (protein inhibitor of nNOS) in targeting of nNOS to the sarcolemma and the association between nNOS and the dystrophin complex in normal and dystrophic muscle fibers. Northern blotting for PIN mRNA in normal mouse muscles and muscles of mdx mice (an animal model of DMD) revealed a significant rise in PIN mRNA in dystrophic muscles compared with normal muscles. Immunohistochemical analysis showed that, in normal mouse muscle fibers, PIN expression was localized at the sarcolemma, peripheral nuclei, and the sarcoplasm. By comparison, PIN protein in muscles from mdx mice was more concentrated around the sarcolemma and central nuclei. The presence of PIN protein expression in muscles from mdx mice was evident despite the significant reduction in nNOS and dystrophin protein expressions in these fibers. In muscle sections of DMD patients, the absence of nNOS protein expression was accompanied by maintained PIN expression. Prominent PIN expression was also detectable in macrophages infiltrating dystrophic muscle fibers both in mdx mice and DMD patients. These results suggest that PIN expression in muscles from mdx mice and DMD patients is controlled by factors different from those involved in the regulation of nNOS and dystrophin. Moreover, our results indicate that PIN is not an integral component of the dystrophin complex inside skeletal muscle fibers.     

Quantitative gray‐scale analysis in skeletal muscle ultrasound: A comparison study of two ultrasound devices

Muscle ultrasound is a useful technique to detect neuromuscular disorders. Quantification of muscle echo intensity (EI) using gray‐scale analysis is more reliable and more sensitive compared with visual evaluation of the images. We devised a method to reliably use EI normal values established with one ultrasound device for use with another device. Based on measurements in a dedicated phantom and in 7 healthy subjects, a conversion equation was calculated to convert the mean EI. The reliability of this equation was next evaluated in a follow‐up study of 22 healthy children. Mean muscle EI could be reliably converted from one ultrasound device to another. This allows for normal values obtained with one device to be used with other devices, which is an important step forward toward the use of quantitative muscle ultrasound in daily clinical care. Muscle Nerve, 2009     

Muscle ultrasonography: a diagnostic tool for amyotrophic lateral sclerosis

ObjectiveIn a prospective study we tested whether muscle ultrasonography can differentiate between amyotrophic lateral sclerosis (ALS) and mimics. Furthermore, we assessed the ability of ultrasonography to identify subclinical lower motor neuron involvement.MethodsIn 59 patients, suspected for adult onset motor neuron disease, ultrasound scans were made of 12 different muscle groups. Echo intensity was determined and each muscle was screened for fasciculations. Ultrasonography was considered diagnostic for ALS when echo intensity was 1.5 SD above normal in at least two muscles and fasciculations were present in at least four muscles.ResultsUltrasonography differentiated between ALS and mimics with 96% sensitivity and 84% specificity. In the 27 ALS patients, ultrasonography detected 15 regions with lower motor neuron involvement that were negative using either clinical examination or needle EMG.ConclusionsMuscle ultrasound can differentiate between amyotrophic lateral sclerosis and mimics with high sensitivity and specificity, and is a sensitive tool to screen for regional lower motor neuron involvement.SignificanceMuscle ultrasonography is a promising tool in the diagnostic work up of ALS.     

Proteasome expression in the skeletal muscles of patients with muscular dystrophy

Previous investigators have suggested that proteolysis by calpain, a Ca²⁺-dependent protease, causes muscle fiber degradation in Duchenne and Becker muscular dystrophies (DMD/BMD). Recent evidence indicates that the nonlysosomal ATP-ubiquitin-dependent proteolytic complex (proteasomes) participates in muscle wasting during various catabolic states and in muscle fiber degradation in physiological or pathological conditions. To elucidate the possible role of proteasomes in dystrophic muscles, routine histochemistry and immunohistochemistry of 26S proteasomes were performed on muscle biopsy specimens obtained from patients with various neuromuscular disorders including DMD/BMD, polymyositis (PM), amyotrophic lateral sclerosis, and peripheral neuropathies, and on normal human muscle specimens. Immunohistochemically, proteasomes were located in the cytoplasm in normal human muscle, but their staining intensity was faint. Compared to control muscles, abnormal increases in both proteasomes and ubiquitin were demonstrated mainly in the cytoplasm of necrotic fibers and to a lesser extent in regenerative fibers in DMD/BMD and PM. Non-necrotic, atrophic fibers in all diseased muscles showed moderate or weak immunoreactions for the proteins; their staining intensities were stronger than those of control muscle fibers. Both proteins often colocalized well. Not all dystrophin-deficient muscle fibers showed a strong reaction for proteasomes. Our results showed increased proteasomes in necrotic and regenerative muscle fibers in DMD/ PMD, although this may not be disease-specific up-regulation. We suggest that the ATP-ubiquitin-dependent proteolytic pathway as well as the nonlysosomal calpain pathway may participate in muscle fiber degradation in muscular dystrophy. Received: 9 July 1999 / Revised: 28 December 1999, 21 February 2000 / Accepted: 21 February 2000     

Adenine metabolism in erythrocytes of patients with Duchenne muscular dystrophy

The primarily metabolic defect in Duchenne muscular dystrophy (DMD) is still unknown. In addition to the disturbance of muscle cell and erythrocyte membranes of patients with DMD an impairment of purine metabolism has been suggested on the basis of the decreased ATP content of the muscle fibers. To avoid the leakage of adenine nucleotides from cells, allopurinol has been administered to DMD patients to increase the formation of adenine nucleotides via the salvage pathway. The purpose of this study was to investigate this hypothesis of an effect of allopurinol on the formation of adenine nucleotides. Furthermore, the clinical status of allopurinol-treated DMD patients was examined. Biochemical studies were performed on erythrocytes of 19 patients with DMD, and adenine nucleotide concentrations and the incorporation of 14C-adenine into purine nucleotides were assessed before and after 6 months of allopurinol therapy. No improvement of the clinical status could be observed, although a slight increase in ATP formation was seen.     

Plasma phosphoglycerate mutase as a marker of muscular dystrophy

An elevation of phosphoglycerate mutase (PMG) has been detected in the blood plasma of the genetically dystrophic chicken and in Duchenne muscular dystrophy (DMD) patients. In the dystrophic chicken, plasma PGM in the pectoral muscle was simultaneously depressed to less than one-half that of the normal chicken. In a group of 9 DMD patients, plasma PGM activity was found to be significantly raised above the normal range. A survey of a small group of plasma specimens from human fetuses at risk for muscular dystrophy also suggested that PGM merits investigation as a potential adjunct to other diagnostic indices.     

Bilateral changes in muscle architecture of physically active people with chronic stroke: A quantitative muscle ultrasound study

Objective

Changes in muscle architecture after stroke are usually assessed by investigating inter-limb differences. As a result bilateral changes of muscle architecture might be missed. Our aim was to investigate whether bilateral architectural changes in skeletal muscle can be detected in chronic, physically active stroke patients using quantitative muscle ultrasound (QMUS).

Longitudinal Relationship Between Intramuscular Fat in the Quadriceps and Gait Independence in Convalescent Stroke Patients

Background and AimIn a cross-sectional study, intramuscular fat in the quadriceps of stroke patients has been associated with gait independence. However, the longitudinal relationship between intramuscular fat and gait independence remain unclear. If these relationships are clarified, it can be demonstrated that improvement in gait independence eventually contributes to improved intramuscular fat in the quadriceps of stroke patients. The aim of this study was to investigate the longitudinal relationship between intramuscular fat in the quadriceps and gait independence in convalescent stroke patients.MethodsEleven stroke patients participated in this study. Gait independence was assessed using the Functional Independence Measure (FIM) gait score. The intramuscular fat in the quadriceps was assessed using ultrasound echo intensity, whereas higher echo intensity indicated greater intramuscular fat. The baseline and discharge assessment values for the echo intensity of the quadriceps were compared using a paired t-test. Correlation analysis of the FIM gait score gain and echo intensity changes in the quadriceps on the paretic and non-paretic sides was performed using Kendall's rank correlation coefficient.ResultsFor quadriceps on the paretic side, echo intensity values at discharge were significantly lower than those at admission. However there was no significant difference for quadriceps on the non-paretic side (paretic side: 19.9% decrease; non-paretic side: 8.0% decrease). We observed that the change in the echo intensity of quadriceps on the non-paretic side was negatively corelated with FIM gait score gain.ConclusionsOur results revealed a strong correlation between longitudinal change in intramuscular fat in the quadriceps and gait independence, implying that improved gait independence in convalescent stroke patients might have a positive effect on improvements in intramuscular fat.     

Expression of tissue inhibitor of metalloproteinase-1 in progression muscular dystrophy

Objective Tissue inhibitor of metalloproteinase-1(TIMP-1) is a multifunctional protein that has the capacity to modify cellular activities and to modulate matrix turnover. This paper revealed the contributive role of TIMP-1 in progressive muscular dystrophy (PMD). Methods We examined the expression and cellular localization of TIMP-1 protein using biopsied frozen muscle from patients with Duchenne muscular dystrophy ( DMD) , Becker muscular dystrophy (BMD) , congenital muscular dystrophy (CMD) by immunohistochemistry, double immunofluorescence and Western blot analysis. Results The results of immunohistochemistry and double immunofluorescence showed that TIMP-1 was positive only in vascular endothelial cells of normal muscles. Immunohistochemistry and Western blot analysis showed that the staining intensity was distinctly increased in some dystrophic muscles of PMD for TIMP-1. Double immunofluorescence revealed that TIMP-1 strongly expressed in the regenerating muscle fibers, macrophages and macrophage infiltrating necrotic fibers. Some activated fibroblasts in endomysium and perimysium of DMD and CMD muscles were also positive for TIMP-1. Conclusion The functional consequence of overexpression of TIMP-1 in the dystrophic muscles is unknown, but the elevated local expression of TIMP-1 in diseased muscles of PMD and their distinct distribution pattern provide evidence that TIMP-1 may participate in the pathogenesis of PMD.     

Hematopoietic prostaglandin D synthase inhibitors for the treatment of duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is a severe X-linked muscle disease, characterized by progressive skeletal muscle atrophy and weakness. DMD is caused by mutations in the dystrophin gene, which encodes for the cytoskeletal protein dystrophin. DMD is one of the most common types of muscular dystrophies, affecting approximately 1 in 3,500 boys. There is no complete cure for this disease. Clinical trials for gene transfer therapy as a treatment for DMD have been performed but mainly in animal models. Hematopoietic prostaglandin (PG) D synthase (H-PGDS) was found to be induced in grouped necrotic muscle fibers of DMD patients and animal models, mdx mice, and DMD dogs. We found an orally active H-PGDS inhibitor (HQL-79) and determined the 3D structure of the inhibitor-human H-PGDS complex by X-ray crystallography. Oral administration of HQL-79 markedly suppressed prostaglandin D₂ (PGD₂) production, reduced necrotic muscle volume, and improved muscle strength in mdx dystrophic mice. Based on the high-resolution 3D structures of the inhibitor-H-PGDS complex, we designed alternative H-PGDS inhibitors, which were 100- to 3000-times more potent than HQL-79, as assessed by in vitro and in vivo analyses. We used these novel inhibitors for the treatment of DMD dogs and confirmed that oral administration of these inhibitors prevented skeletal muscle atrophy and weakness by decreasing PGD₂ production. These results indicate that PGD₂, synthesized by H-PGDS, is involved in the expansion of muscle necrosis in DMD. Thus, inhibition of H-PGDS by using inhibitors is a novel therapy for DMD.