Mitochondrial Complex Abundance, Mitophagy Proteins, and Physical Performance in People With and Without Peripheral Artery Disease.

Background Mitochondrial abnormalities exist in gastrocnemius muscle of people with peripheral artery disease (PAD). Whether abnormalities in mitochondrial biogenesis and autophagy are associated with greater ischemia or walking impairment in PAD is unknown. Methods and Results Protein markers of mitochondrial biogenesis and autophagy and the abundance of mitochondrial electron transport chain complexes were quantified in gastrocnemius muscle biopsies from people with and without PAD. Their 6-minute walk distance and 4-m gait speed were measured. Sixty-seven participants (mean age 65.0 years [±6.8], 16 [23.9%] women, 48 [71.6%] Black) were enrolled, including 15 with moderate to severe PAD (ankle brachial index [ABI] <0.60), 29 with mild PAD (ABI 0.60-0.90), and 23 without PAD (ABI 1.00-1.40). Abundance of all electron transport chain complexes was significantly higher in participants with lower ABI (eg, complex I: 0.66, 0.45, 0.48 arbitrary units [AU], respectively, P trend=0.043). Lower ABI values were associated with a higher LC3A/B II-to-LC3A/B I (microtubule-associated protein 1A/1B-light chain 3) ratio (2.54, 2.31, 2.15 AU, respectively, P trend=0.017) and reduced abundance of the autophagy receptor p62 (0.71, 0.69, 0.80 AU, respectively, P trend=0.033). The abundance of each electron transport chain complex was positively and significantly associated with 6-minute walk distance and 4-m gait speed at usual and fast pace only among participants without PAD (eg, complex I: r=0.541, P=0.008; r=0.477, P=0.021; r=0.628, P=0.001, respectively). Conclusions These results suggest that accumulation of electron transport chain complexes in gastrocnemius muscle of people with PAD may be because of impaired mitophagy in the setting of ischemia. Findings are descriptive, and further study in larger sample sizes is needed.

Unusually severe muscular dystrophy upon in-frame deletion of the dystrophin rod domain and lack of compensation by membrane-localized utrophin.

BACKGROUND: Utrophin, a dystrophin homolog, is consistently upregulated in muscles of patients with Duchenne muscular dystrophy (DMD) and is believed to partially compensate for the lack of dystrophin in dystrophic muscle. Even though several animal studies support the idea that utrophin can modulate DMD disease severity, human clinical data are scarce. METHODS: We describe a patient with the largest reported in-frame deletion in the DMD gene, including exons 10-60 and thus encompassing the entire rod domain. FINDINGS: The patient presented with an unusually early and severe progressive weakness, initially suggesting congenital muscular dystrophy. Immunostaining of his muscle biopsy showed that the mutant protein was able to localize at the sarcolemma and stabilize the dystrophin-associated complex. Strikingly, utrophin protein was absent from the sarcolemmal membrane despite the upregulation of utrophin mRNA. CONCLUSIONS: Our results suggest that the internally deleted and dysfunctional dystrophin lacking the entire rod domain may exert a dominant-negative effect by preventing upregulated utrophin protein from reaching the sarcolemmal membrane and thus blocking its partial rescue of muscle function. This unique case may set a lower size limit for similar constructs in potential gene therapy approaches. FUNDING: This work was supported by a grant from MDA USA (MDA3896) and by grant number R01AR051999 from NIAMS/NIH to C.G.B.

Dysregulated Genes, MicroRNAs, Biological Pathways, and Gastrocnemius Muscle Fiber Types Associated With Progression of Peripheral Artery Disease: A Preliminary Analysis.

Background Peripheral artery disease (PAD) is associated with gastrocnemius muscle abnormalities. However, the biological pathways associated with gastrocnemius muscle dysfunction and their associations with progression of PAD are largely unknown. This study characterized differential gene and microRNA (miRNA) expression in gastrocnemius biopsies from people without PAD compared with those with PAD. Participants with PAD included those with and without PAD progression. Methods and Results mRNA and miRNA sequencing were performed to identify differentially expressed genes, differentially expressed miRNAs, mRNA-miRNA interactions, and associated biological pathways for 3 sets of comparisons: (1) PAD progression (n=7) versus non-PAD (n=7); (2) PAD no progression (n=6) versus non-PAD; and (3) PAD progression versus PAD no progression. Immunohistochemistry was performed to determine gastrocnemius muscle fiber types and muscle fiber size. Differentially expressed genes and differentially expressed miRNAs were more abundant in the comparison of PAD progression versus non-PAD compared with PAD with versus without progression. Among the top significant cellular pathways in subjects with PAD progression were muscle contraction or development, transforming growth factor-beta, growth/differentiation factor, and activin signaling, inflammation, cellular senescence, and notch signaling. Subjects with PAD progression had increased frequency of smaller Type 2a gastrocnemius muscle fibers in exploratory analyses. Conclusions Humans with PAD progression exhibited greater differences in the number of gene and miRNA expression, biological pathways, and Type 2a muscle fiber size compared with those without PAD. Fewer differences were observed between people with PAD without progression and control patients without PAD. Further study is needed to confirm whether the identified transcripts may serve as potential biomarkers for diagnosis and progression of PAD.

Mitochondrial DNA damage in calf skeletal muscle and walking performance in people with peripheral artery disease.

BACKGROUND: Peripheral artery disease (PAD) is associated with mitochondrial dysfunction in calf skeletal muscle and a greater abundance of mitochondrial DNA (mtDNA) heteroplasmy. However, it is unknown whether calf skeletal muscle mtDNA of PAD participants harbors a greater abundance of mitochondrial DNA 4977-bp common deletion (mtDNA4977), strand breaks and oxidative damage (i.e., oxidized purines) compared to non-PAD participants and whether these mtDNA abnormalities are associated with poor walking performance in participants with PAD. METHODS: Calf muscle biopsies were obtained from 50 PAD participants (ankle-brachial index (ABI) < 0.95) and 25 non-PAD participants (ABI = 0.99-1.40) matched by age, sex, and race. The abundance of mtDNA copy number, mtDNA4977 deletion, strand breaks, and oxidized purines in selected mtDNA regions coding for electron transport chain (ETC) constituents and the non-coding D-Loop region was determined in calf muscle. All participants completed measurement of 6-min walk and usual and fast-paced 4-m walking velocity test. RESULTS: Participants with PAD (mean age = 65.4 years, SD = 6.9; 14 (28%) women, 38 (76%) black) and without PAD (mean age = 65.2 years, SD = 6.7; 7 (28%) women, 16 (64%) black) did not differ in the abundance of calf muscle mtDNA4977 deletion, mtDNA strand breaks, and oxidized purines. Though, a greater abundance of mtDNA strand breaks within ND4/5 genes was significantly associated with poorer 6-min walk distance, lower usual-paced 4-m walking velocity, and lower fast-paced 4-m walking velocity in non-PAD participants. Significant associations were also found in the density of strand break damage (i.e., damage per mtDNA copy) within ND1/2, ND4/5 and COII/ATPase 6/8 region with 6-min walk distance, usual-paced 4-m walking velocity and fast-paced 4-m walking velocity in non-PAD participants. Significant interactions were found between PAD presence vs. absence and density of strand break damage within ND1/2, ND4/5, COII/ATPase 6/8 regions for the associations with 6-min walk distance, usual-paced 4-m walking velocity, fast-paced 4-m walking velocity. Conversely, of the three walking performance measures only the usual-paced 4-m walking velocity showed a significant, although modest, negative association with the abundance of oxidized purines in the D-Loop (P = 0.031) and ND4/5 (P = 0.033) regions in the calf skeletal muscle of people with PAD. CONCLUSION: Overall, these data suggest that the abundance of calf muscle mtDNA strand breaks and mtDNA4977 common deletion are not associated with walking performance in people with PAD and may not be directly involved in the pathophysiology of PAD. Conversely, strand breaks in specific mtDNA regions may contribute to poor walking performance in people without PAD. Further study is needed to confirm whether usual-paced 4-m walking velocity is associated significantly with a greater abundance of oxidized purines in the D-loop, a "mutational hotspot" for oxidative damage, and why this association may differ from the association with 6-min walk distance and fast-paced 4-m walking velocity.

Associations of Poly (ADP-Ribose) Polymerase1 abundance in calf skeletal muscle with walking performance in peripheral artery disease.

OBJECTIVE: This study investigated associations of markers of oxidative stress and mitochondrial function in calf muscle biopsies with walking performance in people with and without lower extremity peripheral artery disease (PAD). METHODS: Participants with PAD (ankle-brachial index (ABI) <0.90) and without PAD (ABI: 0.90-1.50) underwent calf muscle biopsy and measurement of 6-min walk and four-meter walking velocity. PARP1 (Poly (ADP-Ribose) Polymerase 1), peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), silent information regulator 1 (SIRT1) and 4-hydroxynonenal (4HNE) expression were measured in calf muscle using western blot. RESULTS: Among 15 participants with PAD mean age: 66.8 years (standard deviation (SD): 6.4) and six without PAD (age: 64.4 years, SD: 5.9), mean PARP1-abundance in calf muscle was 1.16 ± 0.92 AU and 0.96 ± 0.38 AU, respectively (P = 0.61). Among participants with PAD after adjustment with ABI, a greater abundance of PARP1 was associated with poorer 6-min walking distance (r = -0.65, P = 0.01), usual-paced 4-m walking velocity (r = -0.73, P = 0.003) and slower fast-paced four-meter walking velocity (r = -0.51, P = 0.07). Among participants with PAD, ABI was not associated with PARP1 abundance in calf muscle (r = 0.02, P = 0.93). Among participants without PAD, skeletal muscle PARP1 abundance was not significantly associated with 6-min walk distance (r = -0.58; P = 0.22), usual-paced walking velocity (r = -0.26; P = 0.62), or fast-paced walking velocity (r = -0.21; P = 0.69), perhaps due to lack of statistical power. There were no associations of remaining calf muscle measures with walking performance. CONCLUSIONS: These findings are consistent with the hypothesis that calf skeletal muscle characteristics are related to walking performance, independently of severity of lower extremity arterial obstruction in people with PAD.

Correlations of Calf Muscle Macrophage Content With Muscle Properties and Walking Performance in Peripheral Artery Disease.

Background Peripheral artery disease (PAD) is a manifestation of atherosclerosis characterized by reduced blood flow to the lower extremities and mobility loss. Preliminary evidence suggests PAD damages skeletal muscle, resulting in muscle impairments that contribute to functional decline. We sought to determine whether PAD is associated with an altered macrophage profile in gastrocnemius muscles and whether muscle macrophage populations are associated with impaired muscle phenotype and walking performance in patients with PAD. Methods and Results Macrophages, satellite cells, and extracellular matrix in gastrocnemius muscles from 25 patients with PAD and 7 patients without PAD were quantified using immunohistochemistry. Among patients with PAD, both the absolute number and percentage of cluster of differentiation (CD) 11b+CD206+ M2-like macrophages positively correlated to satellite cell number (r=0.461 [P=0.023] and r=0.416 [P=0.042], respectively) but not capillary density or extracellular matrix. The number of CD11b+CD206- macrophages negatively correlated to 4-meter walk tests at normal (r=-0.447, P=0.036) and fast pace (r=-0.510, P=0.014). Extracellular matrix occupied more muscle area in PAD compared with non-PAD (8.72±2.19% versus 5.30±1.03%, P<0.001) and positively correlated with capillary density (r=0.656, P<0.001). Conclusions Among people with PAD, higher CD206+ M2-like macrophage abundance was associated with greater satellite cell numbers and muscle fiber size. Lower CD206- macrophage abundance was associated with better walking performance. Further study is needed to determine whether CD206+ macrophages are associated with ongoing reparative processes enabling skeletal muscle adaptation to damage with PAD. Registration URL: https://www.clini​caltr​ials.gov; Unique identifiers: NCT00693940, NCT01408901, NCT0224660.

Associations of Peripheral Artery Disease With Calf Skeletal Muscle Mitochondrial DNA Heteroplasmy.

Background Patients with peripheral artery disease (PAD) undergo frequent episodes of ischemia-reperfusion in lower extremity muscles that may negatively affect mitochondrial health and are associated with impaired mobility. We hypothesized that skeletal muscle from PAD patients will show high mitochondrial DNA heteroplasmy, especially in regions more susceptible to oxidative damage, such as the displacement loop, and that the degree of heteroplasmy will be correlated with the severity of ischemia and mobility impairment. Methods and Results Mitochondrial mutations and deletions and their relative abundance were identified by targeted mitochondrial DNA sequencing in biopsy specimens of gastrocnemius muscle from 33 PAD (ankle brachial index <0.9) and 9 non-PAD (ankle brachial index >0.9) subjects aged ≥60 years. The probability of heteroplasmy per DNA base was significantly higher for PAD subjects than non-PAD within each region. In adjusted models, PAD was associated with higher heteroplasmy than non-PAD (P=0.003), but the association was limited to microheteroplasmy, that is heteroplasmy found in 1% to 5% of all mitochondrial genomes (P=0.004). Heteroplasmy in the displacement loop and coding regions were significantly higher for PAD than non-PAD subjects after adjustment for age, sex, race, and diabetes mellitus (P=0.037 and 0.004, respectively). Low mitochondrial damage, defined by both low mitochondrial DNA copy number and low microheteroplasmy, was associated with better walking performance. Conclusions People with PAD have higher "low frequency" heteroplasmy in gastrocnemius muscle compared with people without PAD. Among people with PAD, those who had evidence of least mitochondrial damage, had better walking performance than those with more mitochondrial damage. Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT02246660.

Associations of Weight Change With Changes in Calf Muscle Characteristics and Functional Decline in Peripheral Artery Disease.

Background Among people with lower extremity peripheral artery disease, obesity is associated with faster functional decline than normal weight. The association of weight loss with functional decline in peripheral artery disease is unknown. Methods and Results Adults with an ankle-brachial index <0.90 were identified from Chicago-area hospitals in 2002-2004. Weight and 6-minute walk distance were measured annually. Weight change categories were weight loss or gain (≥5 pounds/year at ≥1 visit) or stable (weight change <5 pounds at each visit). Participants reported whether weight loss was "intentional" or "unintentional." Calf muscle area was measured with computed tomography every 2 years. Associations of weight change with changes in calf muscle area and 6-minute walk distance were analyzed using mixed-effects models and adjusted for age, body mass index, ankle-brachial index, physical activity, and other confounders. Among 389 participants, mean ankle-brachial index was 0.63±0.16, mean age was 74.5±7.8, and mean body mass index was 28.1±5.1 kg/m2. Over 3.23±1.37 years, muscle area declined more in adults with intentional weight loss versus stable or gain (pair-wise comparisons, P<0.001). Intentional weight loss was associated with less annual decline in 6-minute walk distance than weight gain (intentional loss, 3.7 m; stable, -14.0 m; gain, -28.5 m; unintentional loss, -20.8 m; pair-wise comparison intentional loss versus gain, P=0.003). Conclusions Despite a greater loss of calf muscle area, adults with peripheral artery disease who intentionally lost ≥5 pounds experienced less functional decline than those who gained weight. A randomized trial is needed to establish whether benefits of weight loss in peripheral artery disease outweigh potential adverse effects.

Open label study to assess the safety of VM202 in subjects with amyotrophic lateral sclerosis.

OBJECTIVE: To assess safety and define efficacy measures of hepatocyte growth factor (HGF) DNA plasmid, VM202, administered by intramuscular injections in patients with amyotrophic lateral sclerosis (ALS). METHODS: Eighteen participants were treated with VM202 administered in divided doses by injections alternating between the upper and lower limbs on d 0, 7, 14, and 21. Subjects were followed for nine months to evaluate possible adverse events. Functional outcome was assessed using the ALS Functional Rating Scale-Revised (ALSFRS-R) as well as by serially measuring muscle strength, muscle circumference, and forced vital capacity. RESULTS: Seventeen of 18 participants completed the study. All participants tolerated 64 mg of VM202 well with no serious adverse events (SAE) related to the drug. Twelve participants reported 26 mild or moderate injection site reactions. Three participants experienced five SAEs unrelated to VM202. One subject died from respiratory insufficiency secondary to ALS progression. CONCLUSIONS: Multiple intramuscular injection of VM202 into the limbs appears safe in ALS subjects. Future trials with retreatment after three months will determine whether VM202 treatment alters the long-term course of ALS.

Walking performance is positively correlated to calf muscle fiber size in peripheral artery disease subjects, but fibers show aberrant mitophagy: an observational study.

BACKGROUND: Patients with lower extremity peripheral artery disease (PAD) have decreased mobility, which is not fully explained by impaired blood supply to the lower limb. Additionally, reports are conflicted regarding fiber type distribution patterns in PAD, but agree that skeletal muscle mitochondrial respiration is impaired. METHODS: To test the hypothesis that reduced muscle fiber oxidative activity and type I distribution are negatively associated with walking performance in PAD, calf muscle biopsies from non-PAD (n = 7) and PAD participants (n = 26) were analyzed immunohistochemically for fiber type and size, oxidative activity, markers of autophagy, and capillary density. Data were analyzed using analysis of covariance. RESULTS: There was a wide range in fiber type distribution among subjects with PAD (9-81 % type I fibers) that did not correlate with walking performance. However, mean type I fiber size correlated with 4-min normal- and fastest-paced walk velocity (r = 0.4940, P = 0.010 and r = 0.4944, P = 0.010, respectively). Although intensity of succinate dehydrogenase activity staining was consistent with fiber type, up to 17 % of oxidative fibers were devoid of mitochondria in their cores, and the core showed accumulation of the autophagic marker, LC3, which did not completely co-localize with LAMP2, a lysosome marker. CONCLUSIONS: Calf muscle type I fiber size positively correlates with walking performance in PAD. Accumulation of LC3 and a lack of co-localization of LC3 with LAMP2 in the area depleted of mitochondria in PAD fibers suggests impaired clearance of damaged mitochondria, which may contribute to reduced muscle oxidative capacity. Further study is needed to determine whether defective mitophagy is associated with decline in function over time, and whether interventions aimed at preserving mitochondrial function and improving autophagy can improve walking performance in PAD.

Distal acquired demyelinating symmetric neuropathy after vaccination.

Neuropathy after vaccination is a rare event. Chronic immune-mediated polyneuropathy developing in the postvaccination period is distinctly unusual and not well described. Almost all such patients have been reported as having typical chronic inflammatory demyelinating polyneuropathy. Distal acquired demyelinating symmetric neuropathy, unlike classic chronic inflammatory demyelinating polyneuropathy, is characterized by distally predominant sensory symptoms with no or mild distal weakness. We describe the clinical, laboratory, and neurophysiological findings of 2 patients who developed distal acquired demyelinating symmetric neuropathy after vaccination. Immunomodulatory therapy led to clinical improvement in both cases. The literature is reviewed with attention to the clinical features of chronic immune-mediated neuropathies that follow vaccination.

Gastrostomy tube placement by endoscopy versus radiologic methods in patients with ALS: a retrospective study of complications and outcome.

Gastrostomy tube placement for malnutrition and weight loss stabilization occurs in many patients with ALS. We sought to compare the outcome and complications of gastrostomy tube placement by endoscopic (PEG) and multiple radiologic (RIG) methods in ALS patients. A retrospective analysis was conducted on all ALS patients evaluated at Northwestern University who received gastrostomy tubes between January 2009 and March 2012. One hundred and eight gastrostomy tube attempts were made on a total of 100 different patients. Failed gastrostomy tube placement occurred in 15.7% of PEGs and 1.9% of RIGs. Post-procedure aspiration was recognized after 10.5% PEG and 0 RIG attempts. Multivariate analysis revealed a linear increase in risk of post-procedure aspiration for every increase in ALSFRS swallow score. No statistically significant differences in failure or complications were observed when comparing two different methods of RIG (push-type vs. pull-type). Our findings support gastrostomy tube placement by radiographic methods in ALS patients. Gastrostomy tube placement by RIG was more often successful and less often associated with aspiration. Our findings add to the growing body of literature that argues for early gastrostomy tube placement in young patients with prominent bulbar involvement.

SQSTM1 mutations in familial and sporadic amyotrophic lateral sclerosis.

BACKGROUND: The SQSTM1 gene encodes p62, a major pathologic protein involved in neurodegeneration. OBJECTIVE: To examine whether SQSTM1 mutations contribute to familial and sporadic amyotrophic lateral sclerosis (ALS). DESIGN: Case-control study. SETTING: Academic research. Patients  A cohort of 546 patients with familial (n = 340) or sporadic (n = 206) ALS seen at a major academic referral center were screened for SQSTM1 mutations. MAIN OUTCOME MEASURES: We evaluated the distribution of missense, deletion, silent, and intronic variants in SQSTM1 among our cohort of patients with ALS. In silico analysis of variants was performed to predict alterations in p62 structure and function. RESULTS: We identified 10 novel SQSTM1 mutations (9 heterozygous missense and 1 deletion) in 15 patients (6 with familial ALS and 9 with sporadic ALS). Predictive in silico analysis classified 8 of 9 missense variants as pathogenic. CONCLUSIONS: Using candidate gene identification based on prior biological knowledge and the functional prediction of rare variants, we identified several novel SQSTM1 mutations in patients with ALS. Our findings provide evidence of a direct genetic role for p62 in ALS pathogenesis and suggest that regulation of protein degradation pathways may represent an important therapeutic target in motor neuron degeneration.

Mutations in UBQLN2 cause dominant X-linked juvenile and adult-onset ALS and ALS/dementia.

Amyotrophic lateral sclerosis (ALS) is a paralytic and usually fatal disorder caused by motor-neuron degeneration in the brain and spinal cord. Most cases of ALS are sporadic but about 5-10% are familial. Mutations in superoxide dismutase 1 (SOD1), TAR DNA-binding protein (TARDBP, also known as TDP43) and fused in sarcoma (FUS, also known as translocated in liposarcoma (TLS)) account for approximately 30% of classic familial ALS. Mutations in several other genes have also been reported as rare causes of ALS or ALS-like syndromes. The causes of the remaining cases of familial ALS and of the vast majority of sporadic ALS are unknown. Despite extensive studies of previously identified ALS-causing genes, the pathogenic mechanism underlying motor-neuron degeneration in ALS remains largely obscure. Dementia, usually of the frontotemporal lobar type, may occur in some ALS cases. It is unclear whether ALS and dementia share common aetiology and pathogenesis in ALS/dementia. Here we show that mutations in UBQLN2, which encodes the ubiquitin-like protein ubiquilin 2, cause dominantly inherited, chromosome-X-linked ALS and ALS/dementia. We describe novel ubiquilin 2 pathology in the spinal cords of ALS cases and in the brains of ALS/dementia cases with or without UBQLN2 mutations. Ubiquilin 2 is a member of the ubiquilin family, which regulates the degradation of ubiquitinated proteins. Functional analysis showed that mutations in UBQLN2 lead to an impairment of protein degradation. Therefore, our findings link abnormalities in ubiquilin 2 to defects in the protein degradation pathway, abnormal protein aggregation and neurodegeneration, indicating a common pathogenic mechanism that can be exploited for therapeutic intervention.

Reversible demyelinating neuropathy associated with renal cell carcinoma.

Paraneoplastic neuropathy is a potential complication of renal cell carcinoma. The clinical and electrophysiologic features of such patients have not been well characterized. We describe a patient with a demyelinating neuropathy associated with papillary renal cell carcinoma that resolved following nephrectomy. The literature is reviewed with particular attention to the clinical, electrophysiologic, and kidney histopathologic characteristics of similar patients. Features arguing against other acquired demyelinating neuropathies are highlighted, and we conclude that abdominal imaging may provide important diagnostic data in some patients with evolving demyelinating neuropathies. The significance of papillary renal cell carcinoma (as opposed to clear renal cell carcinoma) is unknown, but may have important pathophysiologic implications.

Promoting excellence in end-of-life care in ALS.

The type and quality of end-of-life care varies greatly in ALS; the time to initiate end-of-life care is not defined, and decision making is hampered by logistical and financial barriers. There has been no systematic review of these issues in ALS. The goals of this initiative are to: 1) improve end-of-life care for patients with ALS and families based on what limited evidence is available; 2) increase awareness, interest, and debate on the end-of-life care in ALS; and 3) identify areas needed for new prospective clinical research. The ALS Peer Workgroup reviewed the literature and 1) identified the current state of knowledge, 2) analysed the gaps in care, and 3) provided recommendations for standard of care and future research. It was shown that areas of investigation are needed on the incorporation of an interdisciplinary approach to care in ALS that includes: psychosocial evaluation and spiritual care; the use of validated instruments to assess patient and caregiver quality of life; and the establishment of proactive caregiver programs. Several public policy changes that will improve coverage for medical care, hospice, and caregiver costs are also reviewed. More clinical evidence is needed on how to provide optimal end-of-life care specifically in ALS.

Compression of the brachial plexus during right lobe liver donation as a cause of brachial plexus injury: a case report.

We present a case of brachial plexus injury in a living-related liver donor, most likely caused by compression of the plexus between the 1st rib and clavicle, the result of rib retraction for surgical exposure.

Prolonged compound muscle action potential duration in critical illness myopathy: report of nine cases.

The objective of this study was to determine the diagnostic use of compound muscle action potential duration in patients with critical illness myopathy. Accurate diagnosis is important because the muscles recover once the offending agents are withdrawn. We retrospectively reviewed 9 cases seen at our institution between 1999 and 2003 in which critical illness myopathy was diagnosed on the basis of clinical and electrophysiological evaluations. All the patients had weakness, difficulty weaning from mechanical ventilation, sepsis, and exposure to intravenous corticosteroids in the intensive-care unit. Seventy-five percent of tested motor nerves had responses. Amplitude was decreased in 100% of ulnar and peroneal nerves, and 71% of median and tibial nerves. Duration was prolonged in 100% of responsive motor nerves. Prolonged compound muscle action potential duration was the most characteristic electrophysiological finding of critical illness myopathy. Its recognition as part of a quick and simple bedside diagnostic test makes it preferable to other tests.