Upper limb muscle imbalance in tennis elbow: A functional and electromyographic assessment

The purpose of this study was to investigate strength, fatigability, and activity of upper limb musculature to elucidate the role of muscular imbalance in the pathophysiology of tennis elbow. Sixteen patients clinically diagnosed with tennis elbow, recruited from a university hospital upper limb orthopedic clinic, were compared with 16 control subjects with no history of upper limb musculoskeletal problem, recruited from university students and staff. Muscle strength was measured for grip, metacarpophalangeal, wrist, and shoulder on both sides. Electromyographic activity (RMS amplitude) and fatigue characteristics (median frequency slope) of five forearm and two shoulder muscles were measured during isometric contraction at 50% maximum voluntary contraction. All strength measurements showed dominance difference in C, but none in TE. In tennis elbow compared to controls, hand/wrist and shoulder strength and extensor carpi radialis (ECR) activity were reduced (p < 0.05), while fatigue was normal. A global upper limb weakness exists in tennis elbow. This may be due to disuse and deconditioning syndrome caused by fear avoidance, and needs to be addressed in prevention and treatment. Activation imbalance among forearm muscles (reduced extensor carpi radialis activity) in tennis elbow, probably due to protective pain‐related inhibition, could lead to a widespread upper limb muscle imbalance. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:1651–1657, 2007     

The association of low back pain, neuromuscular imbalance, and trunk extension strength in athletes

BACKGROUND CONTEXT: Imbalanced patterns of erector spinae activity and reduced trunk extension strength have been observed among patients with low back pain (LBP). The association between LBP and neuromuscular imbalance still remains unclear. PURPOSE: To examine the relationship between LBP, neuromuscular imbalance, clinical symptoms, and trunk extension strength on two independent occasions, after dynamic neuromuscular changes through a back exercise program. STUDY DESIGN/SETTING: Experimental longitudinal study of the lower back in a clinical setting. PATIENT SAMPLE: Eighty-two elite amateur tennis players with and without LBP. OUTCOME MEASURES: Clinical testing of spinal mobility and muscular flexibility of the lower back. Isometric voluntary maximum trunk extension strength. Surface electromyography (EMG) of lumbar erector spinae. METHODS: Athletes underwent a standardized clinical examination with common tests for spinal mobility and muscular flexibility, followed by an isometric trunk extension tests in a specially built apparatus with simultaneous surface EMG recording from right and left lumbar erector spinae. Imbalance quotients were calculated using integrated EMG (IEMG) measures. The relationships between LBP, neuromuscular imbalance, trunk extension strength, and clinical findings were investigated before and after a back exercise program using univariate and multivariate logistic regression models. RESULTS: A significant association between neuromuscular imbalance of erector spinae and the occurrence of LBP was observed, whereas no significant imbalances were found in subjects without LBP. The number of subjects with LBP decreased proportionally with the occurrence of neuromuscular imbalance in the lumbar region after the completion of a back exercise program. However, neuromuscular imbalances were still present during retesting among subjects whose LBP did not resolve; the relationship between neuromuscular imbalance of lumbar erector spinae and LBP was significant again. On the contrary, no significant association between LBP and maximum isometric trunk extension strength or neuromuscular imbalance and maximum isometric trunk extension strength was found before or after the exercise program. No clear relationship between LBP and clinical testing of the lumbar spine or neuromuscular imbalance and clinical testing was found on the two independent testing occasions. CONCLUSION: A direct relationship between LBP and neuromuscular imbalance was documented in athletes with LBP. Maximum isometric trunk extension strength had no relationship to the presence of LBP or the occurrence of neuromuscular imbalance of erector spinae. Common clinical testing of spinal mobility and muscular flexibility had only limited correlation to LBP and neuromuscular imbalance.     

Oxidative imbalance in idiopathic renal hypouricemia

An important complication of idiopathic renal hypouricemia is exercise-induced acute renal failure (ARF). The most plausible explanation for this complication is that decreased antioxidant potential leads to kidney injury by reactive oxygen species (ROS). We demonstrated this oxidative imbalance by a concomitant assessment of ROS production and antioxidant system capability in a 15- year-old girl with idiopathic renal hypouricemia caused by a mutation in the urate transporter (URAT1) gene. Her serum level of ROS increased with decreasing antioxidant potential capacity soon after the initiation of anaerobic stress due to treadmill exercise. Thereafter, serum levels of ROS and antioxidant potential showed a parallel course, returning to the baseline values at 240 min after exercise. Some patients with idiopathic renal hypouricemia demonstrate oxidative imbalance soon after exercise with a predisposition to exercise-induced acute renal failure. Antioxidant properties may alter this imbalance by augmenting the antioxidant activity.     

Y-27632 improves the erectile dysfunction with ageing in SD rats through adjusting the imbalance between nNo and the Rho-kinase pathways

We investigated whether the effect of Y-27632 to improve the erectile function in SD rats was associated with the degree of the imbalance between nNOS and the Rho-kinase pathways. Western blot analysis was used to evaluate nNOS and Rho-kinase protein expression in 10 young and 10 old SD rats. Imbalance value between nNOS and Rho-kinase protein levels was obtained by subtracting nNOS from Rho-kinase. A 5-V stimulus was given in SD rats before and after the administration of 200 nmol kg(-1) of Y-27632 intracavernosally and ICP/MAP was recorded. The improvement of erectile function induced by Y-27632 was expressed as the margin of ICP/MAP after and before the administration of Y-27632. In young rat group, the contents of nNOS and Rho-kinase protein were 1.7 +/- 0.15 and 1.8 +/- 0.14 respectively. In old rat group, the nNOS protein decreased to 1 +/- 0.15, and in contrast, the Rho-kinase protein increased to 2.6 +/- 0.2. The imbalance value between nNOS and Rho-kinase was 0.2986 +/- 0.1109 and 1.5961 +/- 0.1206 in young and old rat groups. The improvement of erectile function induced by Y-27632 was 0.0500 +/- 0.0294 and 0.3420 +/- 0.660 in young and old rat groups. In all rats, the correlation coefficient between the imbalance value of nNOS and Rho-kinase and the improvement of erectile function was 0.649, P < 0.01. In conclusion, this study suggested that impaired erectile function with ageing in SD rats be associated with the imbalance between nNO and Rho-kinase activity and Y-27632 could improve the erectile function in old SD rats through adjusting this imbalance.     

Imbalance between levels of nitrogen oxides and peroxynitrite inhibitory activity in chronic obstructive pulmonary disease

BACKGROUND: The prevalent theory concerning the pathogenesis of chronic obstructive pulmonary disease (COPD) is of an imbalance between oxidants and antioxidants in the lung. It has recently been reported that the production of peroxynitrite, an extremely potent oxidant, is increased in the airways of patients with COPD. A study was undertaken of the imbalance between the levels of nitrogen oxides and antioxidant activity against peroxynitrite in the airways of patients with COPD. METHODS: Sputum induction was performed in 30 patients with COPD and 15 normal control subjects. Levels of nitrogen oxides, percentage of neutrophils, and interleukin 8 (IL-8) levels were measured in sputum samples, and peroxynitrite inhibitory activity was assayed by monitoring rhodamine formation. RESULTS: Nitrite and nitrate levels in induced sputum were significantly higher in patients with COPD than in normal controls (949 (133) microM v 621 (89) microM, p<0.001). In contrast, peroxynitrite inhibitory activity in induced sputum was significantly lower in patients with COPD than in normal controls (47.4 (12.7)% v 92.9 (3.9)%, p<0.001). There was a negative correlation between nitrite and nitrate levels and peroxynitrite inhibitory activity in induced sputum (r=-0.775, p<0.001). Peroxynitrite inhibitory activity was also significantly correlated with forced expiratory volume in 1 second (FEV(1)) % predicted (r=0.539, p=0.004), FEV(1)/FVC (r=0.512, p=0.006), and carbon monoxide transfer factor (TLCO) (r=0.486, p=0.009). Moreover, there was a significant negative correlation between peroxynitrite inhibitory activity and the degree of neutrophilic inflammation (percentage of neutrophils: r=-0.754, p<0.001; IL-8 levels: r=-0.497, p=0.007). CONCLUSIONS: Reduced peroxynitrite inhibitory activity and increased levels of nitrogen oxides are found in induced sputum from patients with COPD. An imbalance in nitrogen oxides and antioxidant defence may contribute to the pathogenesis of COPD.     

Localization of matrix metalloproteinases and their inhibitors in experimental progressive kidney scarring

The extracellular matrix (ECM) is in a continual state of turnover with homeostasis maintained by balancing synthesis and degradation rates. During progressive kidney scarring an imbalance occurs leading to ECM accumulation. Reduced matrix metalloproteinase (MMP) activity is believed to central to this imbalance. However, most of the data relating to MMPs and their natural inhibitors (tissue inhibitors of matrix metalloproteinase (TIMP)) is based on homogenate studies where in situ compartmentalization is lost and thus changes in MMP activity may be artificial. To address this we have developed a sensitive, high-resolution in situ zymography technique and applied it, along with immunohistochemistry, to the 5/6th subtotal nephrectomy model of kidney scarring. ECM proteolytic activity in kidney homogenates progressively declined post-SNx against both gelatin (-82%) and collagen I (-78%) substrates. In situ zymography revealed higher activity with both substrates within the cytoplasm of normal tubular cells compared to the SNx. In contrast, there was 96% greater activity in the SNx glomeruli than normal. Immunohistochemistry confirmed a predominantly intracellular tubular location of all MMPs and TIMPs. Tubules showed reduced MMP-3 and elevated TIMP-2, whereas MMP-1 increased significantly in the glomeruli, especially in the mesangial matrix. TIMP-1 showed a fourfold increase in the remnant kidney by Western blot analysis, but could not be localized. Lowered MMP activity in homogenates results from reduced intracellular activity in the tubules, indicating that reduced MMP activity may not play a direct role in the expansion of the tubular ECM in scarring. However, elevated MMP-1 activity in the glomeruli may play a significant role in initiating glomerular remodelling.     

Imbalance of osteoclastogenesis-regulating factors in patients with celiac disease.

Celiac disease is an autoimmune disorder characterized by atrophy of the intestine villi triggered by ingestion of gluten in genetically susceptible individuals. The association between celiac disease and low BMD has been recognized, but the mechanisms of disturbance are poorly understood. We show imbalance of cytokines relevant to bone metabolism in celiac patients' sera and the direct effect of these sera on in vitro bone cell activity. INTRODUCTION: Celiac disease is associated with mineral metabolism derangement and low BMD. We investigated whether imbalance of serum factors in celiac patients could affect human bone cell activity in vitro. MATERIALS AND METHODS: We studied two groups of celiac patients--one on a gluten-free diet and another before the diet--both with decreased bone mass. Patients were investigated for bone turnover markers, and their sera were used for culturing bone cells from healthy donors and evaluate changes in cell activity. RESULTS: The N-terminal telopeptide of procollagen type I and interleukin (IL)-6 were higher than normal in patients not on the gluten-free diet. IL-1beta and TNF-alpha/beta were normal in all patients. IL-12 was reduced in all patients, whereas IL-18 was reduced only in patients on the diet. The RANKL/osteoprotegerin (OPG) ratio was increased in patients not on the gluten-free diet. Persistently increased osteoclast numbers were obtained from peripheral blood mononuclear cells of healthy donors on incubation with sera of patients not on the gluten-free diet versus control sera and sera from patients on the diet. In human osteoblasts from healthy individuals, IL-18 was reduced on incubation with sera from all patients, whereas OPG expression was lower when sera from patients not on the diet were used. Proliferation, alkaline phosphatase, and nodule mineralization were increased in osteoblast cultures containing sera from all celiac patients, either on or not on the gluten-free diet.Conclusions: We conclude that bone loss in celiac disease might also be caused by a cytokine imbalance directly affecting osteoclastogenesis and osteoblast activity.     

Alteration in plasma antioxidant capacity in various degrees of chronic renal failure

AIM, PATIENTS AND METHODS: To obtain a more comprehensive profile of extracellular antioxidant capacity in chronic renal failure (CRF), markers of oxidative stress (malondialdehyde, MDA and hydrogen peroxide), protein SH groups (as an important chain-breaking antioxidant) and activity of antioxidant enzymes (glutathione peroxidase, [GPX], catalase and superoxide dismutase, [SOD]) were studied in plasma of 36 non-dialyzed patients with various degrees of CRF and 10 hemodialyzed (HD) patients. RESULTS: The results show that plasma MDA concentrations significantly increase with the severity of kidney dysfunction (r = -0.543, p < 0.01). A marked and profound fall in plasma thiol group levels was observed in all groups tested, independent of the degree of renal failure (r = 0.082, p > 0.05). Plasma SOD activity increased in CRF patients with the progression of renal insufficiency (r = -0.370, p < 0.05). On the other hand, plasma GPX activity decreased progressively in strong correlation with endogenous CCr (r = 0.712, p < 0.001). However, despite this imbalance between extracellular SOD and GPX activities, plasma concentration of hydrogen peroxide remained unchanged in non-dialyzed CRF patients. Catalase activity in non-dialyzed CRF patients was increased, suggesting the significant involvement of catalase in the regulation of plasma hydrogen peroxide level. CONCLUSION: In hemodialyzed patients significantly lower plasma catalase activity, associated with higher hydrogen peroxide levels, was found. It seems reasonable to assume that the imbalance in the activity of extracellular antioxidant enzymes in chronic renal failure may result in accumulation of free radical species, and in unscheduled oxidation of susceptible molecules.     

Adaptation of muscles of the lumbar spine to sudden imbalance in patients with lower back pain caused by military training

Abstract

Objective

This study aims to investigate the effects of sudden load changes (expected and unexpected imbalance) on the activity of muscles of the lumbar spine and their central motor control strategy in military personnel with or without chronic low back pain (LBP).

Design

Bilateral sudden imbalance was examined (2 × 2 factorial design).

Setting

The 117th PLA Hospital, Hangzhou, China

Participants

Twenty-one male subjects with lower back pain and 21 male healthy control subjects were active members of the Nanjing Military Region land forces.

Outcome measures

Independent variables: LBP vs. healthy controls and imbalance anticipation (expected and unexpected imbalance). Dependent variables: rapid reaction time (RRT) and intensity of rapid reaction (IRR) of bilateral lumbar (L3–L4) erector spinae (ES), lumbar (L5–S1) multifidus (MF), and abdominal external oblique muscles.

Results

Under expected or unexpected sudden imbalance conditions, subjects with LBP demonstrated significantly greater IRR than healthy controls in ipsilateral and contralateral ES and MF, respectively (P < 0.05 for all). IRR of contralateral ES was significantly larger than that of the ipsilateral ES. A significant group effect of RRT of both ipsilateral and contralateral ES muscles and a significant time expectation effect on RRT of contralateral MF muscles were also observed. RRT of the contralateral ES muscles was significantly lower than that of the ipsilateral ES muscles (P < 0.001).

Conclusions

Sudden imbalance prolonged RRT of selected trunk muscles in patients with chronic LBP. The activation amplitude increased. The results may provide a theoretical basis for a study on the pathogenesis of chronic LBP.     

Physiological responses to low-force work and psychosocial stress in women with chronic trapezius myalgia

Background  

Repetitive and stressful work tasks have been linked to the development of pain in the trapezius muscle, although the underlying mechanisms still remain unclear. In earlier studies, it has been hypothesized that chronic muscle pain conditions are associated with imbalance in the autonomic nervous system, predominantly expressed as an increased sympathetic activity. This study investigates whether women with chronic trapezius myalgia show higher muscle activity and increased sympathetic tone at baseline and during repetitive low-force work and psychosocial stress, compared with pain-free controls.     

Isometric contractions in the patellofemoral pain syndrome. An electromyographic study

The role played by the vastus lateralis and vastus medialis obliquus in their alignment of the patella during maximal isometric quadriceps contractions was studied by electromyography in 28 patients with unilateral symptoms of the patellofemoral pain syndrome. Eleven knees were classified as subluxation of the patella and 17 as idiopathic chondromalacia patellae. The muscular activity pattern was the same in the two groups but decreased as compared with the contralateral nonsymptomatic knees. However, none of the groups revealed differences in the activity of vastus lateralis and vastus medialis obliquus suggesting muscular imbalance.     

Isometric contractions in the patellofemoral pain syndrome

Summary The role played by the vastus lateralis and vastus medialis obliquus in their alignment of the patella during maximal isometric quadriceps contractions was studied by electromyography in 28 patients with unilateral symptoms of the patellofemoral pain syndrome. Eleven knees were classified as subluxation of the patella and 17 as idiopathic chondromalacia patellae. The muscular activity pattern was the same in the two groups but decreased as compared with the contralateral nonsymptomatic knees. However, none of the groups revealed differences in the activity of vastus lateralis and vastus medialis obliquus suggesting muscular imbalance.     

Effect of Lactobacillus casei DN-114001 application on the activity of fecal enzymes in children after liver transplantation

Immunosuppressive and antibacterial regimens in children after liver transplantation create a gut microflora imbalance that can be indirectly measured by the activity of fecal enzymes. The aim of this study was to specify the influence of diet supplementation with probiotic Lactobacillus casei DN on the activity of beta-glucuronidase, beta-glucosidase, and urease. Twenty-five children after liver transplantation (13 girls, 12 boys) ages 3 to 17 years were enrolled in the study. Two months after bacteria application the levels of all 3 enzymes decreased, reaching statistical significance for beta-glucuronidase and beta-glucosidase. Complete rebound in enzyme activity was observed months after the end of probiotic supplementation. We concluded that Lactobacillus casei DN-114001 consumption decreased fecal enzyme activity, a beneficial effect limited to the period of bacteria intake.     

Role of MMP-9 and its tissue inhibitor TIMP-1 in human osteosarcoma: findings in 42 patients followed for 1-16 years

BACKGROUND: The activity of matrix metalloproteinases (MMPs) in degrading extracellular matrix is controlled by activation of proenzymes and inhibition of MMP tissue inhibitors (TIMPs). PATIENTS AND METHODS: To assess the proteolytic cascade imbalance in malignancy progression, tissue expression and serum levels of MMP-2, MMP-9 and of their inhibitors TIMP-2 and TIMP-1 respectively were evaluated in 42 selected patients with high-grade osteosarcoma (OS). MMP-2, MMP-9, TIMP-2 and TIMP-1 were studied in biopsies by immunohistochemistry and in serum by ELISA test. Patients were subdivided into 3 groups according to their follow up: continuously disease-free, diagnosis of metastasis during follow-up, and metastasis at diagnosis. RESULTS: Immunohistochemistry demonstrated an imbalance between MMPs and TIMPs, with a more evident role for MMP-9 than for MMP-2 in tumor progression. TIMP-1 inhibitor in plasma was higher in patients with osteosarcoma than in a control group. This high value of TIMP-1 was particularly evident in the group of patients who later developed metastases and/or local recurrences, and in those with metastases at diagnosis. INTERPRETATION: Our findings confirm the protective action of TIMP-1, as MMP inhibitor, but also show its activity as a growth factor underlining its multifunctional role in OS.     

Role of MMP-9 and its tissue inhibitor TIMP-1 in human osteosarcomaFindings in 42 patients followed for 1–16 years

Background?The activity of matrix metalloproteinases (MMPs) in degrading extracellular matrix is controlled by activation of proenzymes and inhibition of MMP tissue inhibitors (TIMPs). Patients and methods?To assess the proteolytic cascade imbalance in malignancy progression, tissue expression and serum levels of MMP-2, MMP-9 and of their inhibitors TIMP-2 and TIMP-1 respectively were evaluated in 42 selected patients with high-grade osteosarcoma (OS). MMP-2, MMP-9, TIMP-2 and TIMP-1 were studied in biopsies by immunohistochemistry and in serum by ELISA test. Patients were subdivided into 3 groups according to their follow up: continuously disease-free, diagnosis of metastasis during follow-up, and metastasis at diagnosis. Results?Immunohistochemistry demonstrated an imbalance between MMPs and TIMPs, with a more evident role for MMP-9 than for MMP-2 in tumor progression. TIMP-1 inhibitor in plasma was higher in patients with osteosarcoma than in a control group. This high value of TIMP-1 was particularly evident in the group of patients who later developed metastases and/or local recurrences, and in those with metastases at diagnosis. Interpretation?Our findings confirm the protective action of TIMP-1, as MMP inhibitor, but also show its activity as a growth factor underlining its multifunctional role in OS.     

Serum proteolytic and antiproteolytic activity in acute pancreatitis

This study has demonstrated an imbalance between the blood proteolytic and antiproteolytic system in acute pancreatitis. Serum elastase activity is markedly increased and elastase inhibitory capacity is decreased in this disease as compared with those in chronic pancreatitis and the control values. We have found that a return to normal values represents better evidence of resolution than amylase determinations. These results offer the clinician a biochemical guideline for the medical management of acute pancreatitis.     

特发性脊柱侧凸患者肩部失平衡的临床分析及其意义

目的：对不同类型特发性脊柱侧凸（idiopathic scoliosis,IS）患者肩部失平衡情况进行观察,探讨避免肩部失平衡的融合节段选择方案.方法：对137例随访2年以上资料完整的IS患者进行回顾性分析.对术前及术后的肩部平衡进行影像学评价.根据可能影响肩部平衡的因素（上胸椎侧凸情况、各个侧凸间相互平衡情况及主侧凸角度大小）将患者的Lenke分型进一步分为不同类型.分析各因素及手术融合方式对肩部平衡产生的影响.结果：术前肩部失平衡的病例71例;其中显著肩部失平衡22例;重度肩部失平衡10例,均为Lenke 1型及Lenke 2型.这些患者均存在较大角度的上胸椎侧凸（非结构性或结构性）.术后6例显著肩部失平衡.其中Lenke 1型第一类型1例,Lenke 2型第一类型1例,Lenke 2型第三类型4例,手术方式均为选择性融合.对Lenke 2型第二类型进行双侧凸融合,术后肩部失平衡改善.结论：术前肩部不平衡主要为Lenke 1型及Lenke 2型患者.上胸椎侧凸畸形对肩部平衡产生关键性影响.对Lenke 2型第二及第三类型不建议行选择性融合,对Lenke 2型第一类型进行选择性融合时应避免过度矫正.     

Phenotypic and functional characterization of T cell clones following allogeneic bone marrow transplantation

T cell clones (n = 456) were derived from 9 patients following allogeneic bone marrow transplantation (BMT) with or without acute graft versus host disease (aGVHD) and from 4 healthy donors. The cloning efficiency was 63.2% in controls, 13.2% and 12.1% in patients with or without aGVHD. Once established, T cell clones were typed for surface markers (CD3, CD4, CD8) and tested for production of IL-2 and expression of cytolytic activities in a lectin-dependent cellular cytotoxicity assay (LDCC) and against the K562 target cell line to detect natural killer activity. We found the expected imbalance of CD4/CD8 clones in BMT patients, as compared to controls. A higher proportion of IL-2-producing clones was observed in patients with aGVHD (83.5%; P less than 0.02) as compared to patients without aGVHD (64.8%) and controls (68.5%). No major differences were found in terms of LDCC, whereas an increased percentage of clones with NK-like activity was found in patients with aGVHD (34.7%, P less than 0.05) as compared to patients without aGVHD (29.5%) and controls (21.3%). The clones were also tested for inhibition of IL-2 production mediated by cyclosporine. Such inhibition could be obtained in virtually all clones both in patients with or without aGVHD, suggesting that the latter is probably not due to the emergence of CsA-resistant clones. In conclusion, this study demonstrates a low cloning efficiency in BMT patients associated with the well-known CD4/CD8 imbalance. A higher production of IL-2, an increased NK activity, but not the presence of CsA-resistant clones appear to differentiate patients with from patients without aGVHD.     

Abnormalities in fracture healing induced by vitamin B6-deficiency in rats

Vitamin K₁ is the intermediate carrier of reducing equivalents in mineralization. In fracture-healing in the rat metatarsal the primary source of these reducing equivalents appears to be NADPH, generated from glucose 6-phosphate dehydrogenase (G6PD) activity. Because recent evidence indicated that stimulation of G6PD activity can be induced by putrescine, derived from pyridoxal phosphate-dependent ornithine decarboxylase activity, the effect of pyridoxine (vitamin B₆) deficiency has been studied in this system. Vitamin B₆-deficiency caused marked diminution in the G6PD activity in the periosteal region of bone-formation and in the developing callus, with significant delay in the maturation of the callus and union. It also caused changes in the bone suggestive of imbalance in the coupling between osteoblasts and osteoclasts. These results suggest that the vitamin B₆-status may be important in fracture-healing.