Aging enhances serum cytokine response but not task-induced grip strength declines in a rat model of work-related musculoskeletal disorders

<p>Abstract</p> <p>Background</p> <p>We previously reported early tissue injury, increased serum and tissue inflammatory cytokines and decreased grip in young rats performing a moderate demand repetitive task. The tissue cytokine response was transient, the serum response and decreased grip were still evident by 8 weeks. Thus, here, we examined their levels at 12 weeks in young rats. Since aging is known to enhance serum cytokine levels, we also examined aged rats.</p> <p>Methods</p> <p>Aged and young rats, 14 mo and 2.5 mo of age at onset, respectfully, were trained 15 min/day for 4 weeks, and then performed a high repetition, low force (HRLF) reaching and grasping task for 2 hours/day, for 12 weeks. Serum was assayed for 6 cytokines: IL-1alpha, IL-6, IFN-gamma, TNF-alpha, MIP2, IL-10. Grip strength was assayed, since we have previously shown an inverse correlation between grip strength and serum inflammatory cytokines. Results were compared to naïve (grip), and normal, food-restricted and trained-only controls.</p> <p>Results</p> <p>Serum cytokines were higher overall in aged than young rats, with increases in IL-1alpha, IFN-gamma and IL-6 in aged Trained and 12-week HRLF rats, compared to young Trained and HRLF rats (p < 0.05 and p < 0.001, respectively, each). IL-6 was also increased in aged 12-week HRLF versus aged normal controls (p < 0.05). Serum IFN-gamma and MIP2 levels were also increased in young 6-week HRLF rats, but no cytokines were above baseline levels in young 12-week HRLF rats. Grip strength declined in both young and aged 12-week HRLF rats, compared to naïve and normal controls (p < 0.05 each), but these declines correlated only with IL-6 levels in aged rats (r = -0.39).</p> <p>Conclusion</p> <p>Aging enhanced a serum cytokine response in general, a response that was even greater with repetitive task performance. Grip strength was adversely affected by task performance in both age groups, but was apparently influenced by factors other than serum cytokine levels in young rats.</p

The usefulness of electrodiagnostic consultation in an outpatient clinic

The aim of this study was to record all patients referred to a private outpatient clinic for electrodiagnostic consultation during one calendar year. The demographic data of the patients, the specialty of the referring physicians, the referral diagnosis, the electromyographic (EMG) diagnosis and the concordance of referral and EMG diagnosis among all the referring physician&apos;s specialties were recorded. There were one thousand patients (385 men and 615 women). 65.7% of the patients were referred from orthopedists and 22.4% from neurologists. EMG was normal in 498 patients (49.8%). Abnormal in 47.3% of the patients referred by orthopedists and 58.9% of those referred by neurologists. Carpal tunnel syndrome (CTS) was the most frequent electrophysiological diagnosis (26.8%), followed by polyneuropathy (8.9%), radiculopathy (7.1%) and mononeuropathy (4.6%). In this study electrodiagnostic consultation was abnormal in only half of the referred patients. The high proportion of normal EDX tests in this study denotes the need for more accurate clinical diagnosis in order to reduce the time spent and resources. The orthopedist is the initial physician to whom patients with neuromuscular symptoms are seen in the majority of cases. Neurologists seem to be more familiar with neuromuscular symptoms and diseases. © 2019 Elsevier Lt

Fibrillation potentials in paraspinal muscles in chronic lumbosacral radiculopathy

To assess the rate of fibrillation and/or positive sharp waves (FPSW) in the paraspinal muscles (PM) of patients with chronic lumbosacral radiculopathy, PM and leg muscles of 179 patients, 1 1 1 men and 68 women, aged 24-68 years (mean 49.0 ± 9.3), were tested. Illness duration ranged from 8 months to 40 years (9.4 ± 7.5 years). FPSW were detected in 38 patients (21.2%). In 28 of them (15.6%), FPSW were present in the limb muscles only, in eight (4.5%) in both PM and limb muscles, and in two (1.1%) solely in the PM. FPSW were accompanied in all the above patients by chronic neurogenic changes of motor unit potentials. Logistic regression analysis did not show any significant difference between: (i) the patients with and without fibrillations in leg and/or PM muscles, and (ii) between those with FPSW in both the PM and leg muscles and those with FPSW in the leg muscles only, when the effect of age and duration of illness were considered. These suggest that the paucity of FPSW in the PM is rather genuine and does not depend on the timing of the examination, in consequence, PM electromyography seems to be not as valuable in chronic radiculopathy as it is in the acute stage

Repetitive nerve stimulation of facial and hypothenar muscles: Relative sensitivity in different Myasthenia Gravis subgroups

Aim: To assess the utility of repetitive nerve stimulation (RNS) in facial and hypothenar muscles in the clinical groups of myasthenia gravis (MG). Patients and Methods: We performed RNS study in the orbicularis oculi (O.O.), nasalis and abductor digiti quinti (ADQ) in 115 consecutive myasthenic patients and classified them according to the classifications of the Myasthenia Gravis Foundation of America. Patients were classified into three groups: group 1, group 2 (IIa, IIIa and IVa) and group 3 (IIb, IIIb and IVb). Results: RNS was abnormal in 95 patients (82.6%): 78.3% in the O.O., 66.1% in the nasalis and 19.1% in the ADQ. Both facial muscles were statistically more sensitive than the ADQ in all groups of patients. RNS in the O.O. was more frequently abnormal than in the nasalis only in group 1. Sensitivity to acetylcholine antibodies in myasthenic patients was 84%. Acetylcholine receptor (AChR) and muscle-specific tyrosine kinase antibodies were present in 96.7% of the patients with abnormal RNS in both facial muscles. Single-fiber electromyogram (SFEMG) was abnormal in 91.3% of the tested patients. One of the three tests used for the diagnosis of MG (AChR antibodies, SFEMG, RNS) was abnormal in 99.1% of the patients. Discussion: O.O. is the most sensitive muscle in all groups of MG followed by nasalis, while the ADQ is the muscle with the lowest sensitivity. Facial muscles, especially the O.O., should be the first to be tested in MG. The negativity of all tests (RNS, AChR antibodies, SFEMG) should question the diagnosis of MG, even in the presence of symptoms consistent with MG. Copyright © 2011 S. Karger AG, Basel

Inappropriate surgeries in amyotrophic lateral sclerosis: A still considerable issue

Owing to the variety of its clinical presentations, amyotrophic lateral sclerosis (ALS) may mimic several neurological syndromes and even lead to inappropriate surgical procedures. We wished to assess the impact of unnecessary surgical treatments among ALS patients, and therefore we retrospectively reviewed medical records of 164 consecutive ALS patients. We collected data on the clinical presentation of ALS at onset, the initial symptom that led the patients to seek medical care, the timing of diagnosis and surgical procedures attributed to the onset of symptoms. Results showed that among 164 consecutive patients with ALS, 13 (7.9%) were surgically treated as a consequence of false diagnosis. Despite this, these patients showed no statistically significant difference in time of diagnosis compared to non-operated patients. In conclusion, a small but not negligible number of ALS patients are misdiagnosed. The diagnostic pathway of these patients includes often specialists other than neurologists who should be more aware of this disease in order to avoid inappropriate surgical treatments and provide the patients the appropriate diagnostic and therapeutic procedure by referring them promptly to a neurologist. © 2014 Informa Healthcare

Vibratory testing with the 64 Hz Rydel-Seiffer tuning fork and its relation to the sural nerve action potential

Despite its widespread use, little is known regarding the ability of the semi-quantitative Rydel-Seiffer tuning fork to designate peripheral nerve function. We sought to determine in a large sample of normal and abnormal nerves the relationship between vibration sense and compound sensory nerve action potential (SNAP) parameters recorded in a corresponding innervation area. Vibratory thresholds were determined on a scale of 0 to 8 with a 64 Hz Rydel-Seiffer tuning fork placed on the lateral malleolus of 303 subjects. Sural nerve sensory neurography was employed to derive SNAP parameters, which were related to vibration sense by means of multiple linear regression. ROC curve analysis was performed to determine the classification efficacy of the tuning fork in distinguishing normal from abnormal sural nerve responses. SNAP amplitude was the most significant predictor in the whole subjects group and in the subgroup of subjects with normal SNAPs, whereas conduction velocity played a major role in subjects with abnormal SNAPs. Age was significantly associated with vibration perception, particularly in subjects with normal SNAPs. With an area under the curve of 0.730, vibration sense was a fair classifier for decreased SNAP amplitudes. The optimal vibratory cutoff was 4.2. Age is a major determinant of vibratory test results, highlighting the importance of aging of central and peripheral pathways in mediating vibration sense. Hence, neurophysiological testing cannot be omitted in the context of polyneuropathy work-up, since even at the optimal cutoff threshold, vibratory examination still displays 40% false negative test results. © 2020 Peripheral Nerve Society