Ultrasonography of the accessory nerve: normal and pathologic findings in cadavers and patients with iatrogenic accessory nerve palsy.
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OBJECTIVE: To determine feasibility of ultrasonography in detecting the normal accessory nerve as well as pathologic changes in cases of accessory nerve palsy. METHODS: Four patients with accessory nerve palsy were investigated by ultrasonography. Three cases of accessory nerve palsy after lymph node biopsy and neck dissection were primarily diagnosed on the basis of ultrasonography using a 5- to 12-MHz linear transducer. In addition, we performed ultrasonography in 3 cadaveric specimens to show the feasibility of detecting the accessory nerve. RESULT: Nerve transection (n = 2), scar tissue (n = 1), and atrophy of the trapezius muscle (n = 4) were confirmed by electroneurographic testing and surgical nerve inspection. In 1 case in which a patient had a whiplash injury with accessory nerve palsy, ultrasonography showed atrophy of the trapezius muscle with a normal nerve appearance. CONCLUSIONS: Ultrasonography allows visualization of the normal accessory nerve as well as changes after accessory nerve palsy. (+info)
Altered expression of skeletal muscle myosin isoforms in cancer cachexia.
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Cachexia is commonly seen in cancer and is characterized by severe muscle wasting, but little is known about the effect of cancer cachexia on expression of contractile protein isoforms such as myosin. Other causes of muscle atrophy shift expression of myosin isoforms toward increased fast (type II) isoform expression. We injected mice with murine C-26 adenocarcinoma cells, a tumor cell line that has been shown to cause muscle wasting. Mice were killed 21 days after tumor injection, and hindlimb muscles were removed. Myosin heavy chain (MHC) and myosin light chain (MLC) content was determined in muscle homogenates by SDS-PAGE. Body weight was significantly lower in tumor-bearing (T) mice. There was a significant decrease in muscle mass in all three muscles tested compared with control, with the largest decrease occurring in the soleus. Although no type IIb MHC was detected in the soleus samples from control mice, type IIb comprised 19% of the total MHC in T soleus. Type I MHC was significantly decreased in T vs. control soleus muscle. MHC isoform content was not significantly different from control in plantaris and gastrocnemius muscles. These data are the first to show a change in myosin isoform expression accompanying muscle atrophy during cancer cachexia. (+info)
Increased antioxidant capacity does not attenuate muscle atrophy caused by unweighting.
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Previous studies have increased antioxidant capacity in skeletal muscle to attenuate oxidative stress and muscle atrophy during limb immobilization (Appell HJ, Duarte JAR, and Soares JMC. Int J Sports Med 18: 157-160, 1997; Kondo H, Miura M, Nakagaki I, Sasaki S, and Itokawa Y. Am J Physiol Endocrinol Metab 262: E583-E590, 1992). The purpose of this study was to determine the level of oxidative stress in muscle during hindlimb unweighting (HLU) and whether antioxidant supplementation can attenuate the atrophy and changes in contractile properties resulting from 14 days of unweighting. Muscle unweighting caused a 44% decrease in soleus (Sol) and a 30% decrease in gastrocnemius (GS) mass, a 7% decrease in body weight, and 28% decrease in tetanic force in the GS. Protein carbonyls increased by 44% in the Sol with HLU. Antioxidant supplementation did not attenuate the GS or Sol atrophy or the decrease in GS force generation during HLU. Sol and GS protein concentration was not different between groups. The GS was also subjected to three different oxidative challenges to determine whether the supplement increased the antioxidant capacity of the muscle. In all cases, muscles exhibited an increased antioxidant capacity. These data indicate that antioxidant supplementation was not an effective countermeasure to the atrophy associated with HLU. (+info)
Skeletal muscle IGF-binding protein-3 and -5 expressions are age, muscle, and load dependent.
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The purpose of the current study was to examine IGFBP-3, -4, and -5 mRNA and protein expression levels as a function of muscle type, age, and regrowth from an immobilization-induced atrophy in Fischer 344 x Brown Norway rats. IGFBP-3 mRNA expression in the 4-mo-old animals was significantly higher in the red and white portions of the gastrocnemius muscle compared with the soleus muscle. However, there were no significant differences in IGFBP-3 mRNA expression among any of the muscle groups in the 30-mo-old animals. There were no significant differences in IGFBP-5 mRNA expression in any of the muscle groups, whereas in the 30-mo-old animals there was significantly less IGFBP-5 mRNA expression in the white gastrocnemius compared with the red gastrocnemius muscles. Although IGFBP-3 and -5 proteins were detected in the type I soleus muscle with Western blot analyses, no detection was observed in the type II red and white portions of the gastrocnemius muscle. Aging from adult (18 mo) to old animals (30 mo) was associated with decreases in IGFBP-3 mRNA and protein and IGFBP-5 protein only in the soleus muscle. After 10 days of recovery from 10 days of hindlimb immobilization, IGFBP-3 mRNA and protein increased in soleus muscles from young (4-mo) rats; however, only IGFBP-3 protein increased in the old (30-mo) rats. Whereas there were no changes in IGFBP-5 mRNA expression during recovery, IGFBP-5 protein in the 10-day-recovery soleus muscle did increase in the young, but not in the old, rats. Because one of the functions of IGFBPs is to modulate IGF-I action on muscle size and phenotype, it is hypothesized that IGFBP-3 and -5 proteins may have potential modulatory roles in type I fiber-dominated muscles, aging, and regrowth from atrophy. (+info)
Chronic obstructive pulmonary disease. 5: systemic effects of COPD.
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The role of body cell mass wasting, muscle wasting, and changes in muscle metabolism in the pathogenesis of chronic obstructive pulmonary disease is reviewed. (+info)
Suprascapular nerve entrapment. A meta-analysis.
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We performed a review of the literature between 1959 and 2001. We found 88 cases of suprascapular nerve entrapment, which fulfilled our inclusion criteria. Suprascapular nerve entrapment is rare and mainly occurs in patients under 40 years of age. Males are more likely to suffer from a ganglion compressing the nerve than females. If the patient's history reveals a trauma, it is more likely that the ligament is compromising the nerve. Ganglions usually cause isolated infraspinatus atrophy, whereas a combined atrophy of the supra- and infraspinatus muscles is more common in cases in which the nerve is compressed by the ligament. (+info)
Gyrate atrophy of the choroid and retina: clinical, ophthalmologic, and biochemical considerations.
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A case of gyrate atrophy of the choroid and retina associated with hyperornithinemia has been subjected to extensive clinical and biochemical investigation. The familial occurrence of the ocular disease and of abnormality of amino acid was unique to this 28-year-old male, being absent in parents and siblings. He presented with progressive visual loss, and was found to have cataracts and large areas of peripheral lacunar atrophy. Clinically there was no other abnormality. However, he was hyperuricemic and has an abnormal EEG. Despite otherwise normal biochemical indices of hepatic, renal, and muscle function; selective catheterization of an artery, the hepatic vein, the renal vein, and a deep forearm vein showed all of these circulatory beds to be producing ornithine according to arteriovenous difference measurements. Cerebrospinal fluid and urine contained increased amounts of ornithine. Though electromyography was normal, the muscle biopsy was abnormal. Clinical tests including arginine loading, glucose tolerance testing, and other measurements of blood variables provided inferences as to the metabolic locus of the abnormality. The syndrome is a systemic multiorgan disorder in which the choroid and retina would appear to be target organs and the hyperornithinemia to be of, as yet, undetermined cause and pathogenic significance. (+info)
Expression of a calpastatin transgene slows muscle wasting and obviates changes in myosin isoform expression during murine muscle disuse.
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Muscle wasting is a prominent feature of several systemic diseases, neurological damage and muscle disuse. The contribution of calpain proteases to muscle wasting in any instance of muscle injury or disease has remained unknown because of the inability to specifically perturb calpain activity in vivo. We have generated a transgenic mouse with muscle-specific overexpression of calpastatin, which is the endogenous inhibitor of calpains, and induced muscle atrophy by unloading hindlimb musculature for 10 days. Expression of the transgene resulted in increases in calpastatin concentration in muscle by 30- to 50-fold, and eliminated all calpain activity that was detectable on zymograms. Muscle fibres in ambulatory, transgenic mice were smaller in diameter, but more numerous, so that muscle mass did not differ between transgenic and non-transgenic mice. This is consistent with the role of the calpain-calpastatin system in muscle cell fusion that has been observed in vitro. Overexpression of calpastatin reduced muscle atrophy by 30 % during the 10 day unloading period. In addition, calpastatin overexpression completely prevented the shift in myofibrillar myosin content from slow to fast isoforms, which normally occurs in muscle unloading. These findings indicate that therapeutics directed toward regulating the calpain-calpastatin system may be beneficial in preventing muscle mass loss in muscle injury and disease. (+info)