Surface electromyographic analysis of exercises for the trapezius and serratus anterior muscles

STUDY DESIGN: This study used a prospective, single-group repeated-measures design to analyze differences between the electromyographic (EMG) amplitudes produced by exercises for the trapezius and serratus anterior muscles. OBJECTIVE: To identify high-intensity exercises that elicit the greatest level of EMG activity in the trapezius and serratus anterior muscles. BACKGROUND: The trapezius and serratus anterior muscles are considered to be the only upward rotators of the scapula and are important for normal shoulder function. Electromyographic studies have been performed for these muscles during active and low-intensity exercises, but they have not been analyzed during high intensity exercises. METHODS AND MEASURES: Surface electrodes recorded EMG activity of the upper, middle, and lower trapezius and serratus anterior muscles during 10 exercises in 30 healthy subjects. RESULTS: The unilateral shoulder shrug exercise was found to produce the greatest EMG activity in the upper trapezius. For the middle trapezius, the greatest EMG amplitudes were generated with 2 exercises: shoulder horizontal extension with external rotation and the overhead arm raise in line with the lower trapezius muscle in the prone position. The arm raise overhead exercise in the prone position produced the maximum EMG activity in the lower trapezius. The serratus anterior was activated maximally with exercises requiring a great amount of upward rotation of the scapula. The exercises were shoulder abduction in the plane of the scapula above 120 degrees and a diagonal exercise with a combination of shoulder flexion, horizontal flexion, and external rotation. CONCLUSION: This study identified exercises that maximally activate the trapezius and serratus anterior muscles. This information may be helpful for clinicians in developing exercise programs for these muscles.     

Time-dependent improvement in functional outcome following Oxford medial unicompartmental knee arthroplasty. A prospective longitudinal multicenter study involving 96 patients

Background and purpose

10-year survival rates after unicompartmental knee replacement (UKR) have been up to 97% in single-center studies, but they have been as low as 80% in studies from arthroplasty registers. Few studies have evaluated short-term functional outcome and its improvement with time. We determined the time course of functional outcome as evaluated by the knee injury and osteoarthritis outcome score (KOOS) over the first 2 years after Oxford medial UKR.

Patients and methods

In a prospective multicenter study, we included 99 unselected knees (96 patients, mean age 65 (51–80) years, 57 women) operated with Oxford medial UKR at 3 hospitals in the southeast of Norway between November 2003 and October 2006. Data were collected by independent investigators preoperatively and at 6 weeks, 3 months, 6 months, 1 year, and 2 years postoperatively. KOOS and range of motion (ROM) were determined at all follow-ups.

Results

Mean KOOS values for pain and activities of daily living were improved already after 6 weeks, and increased between each time point up to 2 years postoperatively. However, no statistically significant improvements were seen after 6 months. Mean active and passive ROM gradually improved up to 2 years after UKR, and were then better than before surgery.

Interpretation

Most of the expected improvements in pain and function after UKR are achieved within 6 months of surgery. Only minimal improvement can be expected beyond this time.Unicompartmental knee replacement (UKR) has regained popularity in recent years. Studies comparing UKR to total knee replacement (TKR) have shown faster recovery, shorter hospital stay, more normal kinematics, better range of motion, less blood loss, fewer thromboembolic incidents, and fewer surgical site infections (Li et al. 2006, Walton et al. 2006, Furnes et al. 2007, Lombardi et al. 2009, Newman et al. 2009). Survival rates as high as 96–98% at 10 years have been reported in single-center studies (Murray et al. 1998, Pandit et al. 2011), whereas in studies from national arthroplasty registers 10-year survival rates have been reported to be as low as 80% (Furnes et al. 2007, Koskinen et al. 2008).With a possible higher revision risk for UKR than for TKR (Furnes et al. 2007), more information on pain and function following knee arthroplasty is needed. During the last decade, several authors have emphasized the importance of measuring the patient''s own experience of disability using self-reported questionnaires (Garratt et al. 2004, Tanner et al. 2007) such as the Oxford knee score, the knee injury and osteoarthritis outcome score (KOOS), and the International Knee Documentation Committee (IKDC) standard evaluation form.We determined (1) the time course of patient-relevant functional outcome evaluated by the KOOS, and (2) the time course of range of motion (ROM) during the first 2 years following UKR using the Oxford medial unicompartmental knee prosthesis. Improvements in patients'' self-reported pain and daily function during the study period were of particular interest.     

Increased thrombin generation in splanchnic vein thrombosis is related to the presence of liver cirrhosis and not to the thrombotic event

Introduction

In recent years there have been increasing evidence associating liver disease with hypercoagulability, rather than bleeding. The aim of the study was to evaluate the haemostatic potential in patients with liver disease.

Patients and methods

We measured thrombin generation in the presence and absence of thrombomodulin in patients with portal vein thrombosis (PVT, n = 47), Budd-Chiari syndrome (BCS, n = 15) and cirrhosis (n = 24) and compared the results to those obtained from healthy controls (n = 21). Fifteen patients with PVT and 10 patients with BCS were treated with warfarin and were compared to an equal number of patients with atrial fibrillation matched for prothrombin time-international normalized ratio. We assessed resistance to thrombomodulin by using ratios [marker measured in the presence/absence of thrombomodulin].

Results

There were no differences in thrombin generation between patients on warfarin treatment and their controls. Cirrhotic patients generated more thrombin in the presence of thrombomodulin and exhibited thrombomodulin resistance compared to controls [p = 0.006 for endogenous thrombin potential (ETP) and p < 0.001 for peak thrombin and both ratios ETP and peak] and patients with non-cirrhotic PVT (p = 0.001, p = 0.006, p < 0.001, p < 0.001 for ETP, peak, ratio ETP, ratio peak, respectively). The patients with cirrhotic PVT exhibited higher ETP (p = 0.044) and peak (p = 0.02) in the presence of thrombomodulin than controls, as well as thrombomodulin resistance (ETP and peak ratios: p = 0.001).

Conclusions

Hypercoagulability and thrombomodulin resistance in patients with cirrhosis were independent of the presence of splanchnic vein thrombosis. The hypercoagulability in patients with cirrhotic PVT could have implications for considering longer or more intensive treatment with anticoagulants in this group.     

Late occurring clinical deep vein thrombosis in joint-operated patients

In a prospective study of 4,840 patients, we determined the annual incidence of clinical deep vein thrombosis (DVT) in mobilized, discharged orthopedic-operated "high-risk" patients (hip replacement surgery, knee replacement surgery, nailed hip fracture) and assumed "low-risk" patients (diagnostic knee arthroscopy). In addition, the time from the operation to the time when the patients were readmitted with clinically suspected DVT and the distribution of radiologically-confirmed DVT were recorded. Thromboprophylaxis was routinely given for about 10 days to the high-risk groups during the hospital stay but not to patients undergoing knee arthroscopy. During 9 years, the annual incidence of DVT following major procedures was 2.1% (95% CI 1.6-2.6) vs. 0.6% (95% CI 0.2-1.1) after diagnostic knee arthroscopy. Symptoms appeared, on average, 27 (3-150) days after total hip replacement surgery, 36 (3-150) days after nailed hip fracture, 17 (6-30) days after total knee replacement and 1 (1-6) day after knee arthroscopy. In hip-operated patients, 50% of the DVT's were found in the proximal veins vs. 40% following knee arthroplasty.     

Distinct Subsets of Noncoding RNAs Are Strongly Associated With BMD and Fracture,Studied in Weight-Bearing and Non–Weight-Bearing Human Bone

We investigated mechanisms resulting in low bone mineral density (BMD) and susceptibility to fracture by comparing noncoding RNAs (ncRNAs) in biopsies of non–weight-bearing (NWB) iliac (n = 84) and weight bearing (WB) femoral (n = 18) postmenopausal bone across BMDs varying from normal (T-score > −1.0) to osteoporotic (T-score ≤ −2.5). Global bone ncRNA concentrations were determined by PCR and microchip analyses. Association with BMD or fracture, adjusted by age and body mass index, were calculated using linear and logistic regression and least absolute shrinkage and selection operator (Lasso) analysis. At 10% false discovery rate (FDR), 75 iliac bone ncRNAs and 94 femoral bone ncRNAs were associated with total hip BMD. Eight of the ncRNAs were common for the two sites, but five of them (miR-484, miR-328-3p, miR-27a-5p, miR-28-3p, and miR-409-3p) correlated positively to BMD in femoral bone, but negatively in iliac bone. Of predicted pathways recognized in bone metabolism, ECM-receptor interaction and proteoglycans in cancer emerged at both sites, whereas fatty acid metabolism and focal adhesion were only identified in iliac bone. Lasso analysis and cross-validations identified sets of nine bone ncRNAs correlating strongly with adjusted total hip BMD in both femoral and iliac bone. Twenty-eight iliac ncRNAs were associated with risk of fracture (FDR < 0.1). The small nucleolar RNAs, RNU44 and RNU48, have a function in stabilization of ribosomal RNAs (rRNAs), and their association with fracture and BMD suggest that aberrant processing of rRNAs may be involved in development of osteoporosis. Cis-eQTL (expressed quantitative trait loci) analysis of the iliac bone biopsies identified two loci associated with microRNAs (miRNAs), one previously identified in a heel-BMD genomewide association study (GWAS). In this comprehensive investigation of the skeletal genetic background in postmenopausal women, we identified functional bone ncRNAs associated to fracture and BMD, representing distinct subsets in WB and NWB skeletal sites. © 2020 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research.     

Network-based brain stimulation selectively impairs spatial retrieval

Background

Direct brain stimulation via electrodes implanted for intracranial electroencephalography (iEEG) permits the modulation of endogenous electrical signals with significantly greater spatial and temporal specificity than non-invasive approaches. It also allows for the stimulation of deep brain structures important to memory, such as the hippocampus, that are difficult, if not impossible, to target non-invasively. Direct stimulation studies of these deep memory structures, though, have produced mixed results, with some reporting improvement, some impairment, and others, no consistent changes.

Two closely located areas in the suboesophageal ganglion and the tritocerebrum receive projections of gustatory receptor neurons located on the antennae and the proboscis in the moth Heliothis virescens

Sucrose stimulation of gustatory receptor neurons on the antennae, the tarsi, and the mouthparts elicits the proboscis extension reflex in many insect species, including lepidopterans. The sensory pathways involved in this reflex have only partly been investigated, and in hymenopterans only. The present paper concerns the pathways of the gustatory receptor neurons on the antennae and on the proboscis involved in the proboscis extension reflex in the moth Heliothis virescens (Lepidoptera; Noctuidae). Fluorescent dyes were applied to the contact chemosensilla, sensilla chaetica on the antennae, and sensilla styloconica on the proboscis, permitting tracing of the axons of the gustatory receptor neurons in the central nervous system. The stained axons showed projections from the two appendages in two closely located but distinct areas in the suboesophageal ganglion (SOG)/tritocerebrum. The projections of the antennal gustatory receptor neurons were located posterior-laterally to those from the proboscis. Electrophysiological recordings from the receptor neurons in s. chaetica during mechanical and chemical stimulation were performed, showing responses of one mechanosensory and of several gustatory receptor neurons. Separate neurons showed excitatory responses to sucrose and sinigrin. The effect of these two tastants on the proboscis extension reflex was tested by repeated stimulations with solutions of the two compounds. Whereas sucrose elicited extension in 100% of the individuals in all repetitions, sinigrin elicited extension in fewer individuals, a number that decreased with repeated stimulation.     

Medial septal stimulation increases seizure threshold and improves cognition in epileptic rats

Background

Temporal lobe epilepsy is most prevalent among focal epilepsies, and nearly one-third of patients are refractory to pharmacological intervention. Persistent cognitive and neurobehavioral comorbidities also occur due to the recurrent nature of seizures and medication-related side effects.