Spinal and cortical activity-dependent plasticity following learning of complex arm movements in humans

Activity-dependent plasticity is a fundamental requirement for human motor learning, which takes place at several stages of the motor system and involves various mechanisms in neuronal circuitry. Here, we investigate parameters of cortical and spinal excitability before and immediately after a single session of locomotion-like arm training (LMT) or sequential visuo-motor learning (VMT). Both training paradigms focused especially on mainly activating the flexor carpi radialis muscle (FCR). The activity-dependent change in the excitability of FCR-associated neurons was investigated using standard transcranial magnetic stimulation, including analysis of motor-evoked potentials (MEP) amplitude, short-interval intracortical inhibition and intracortical facilitation (ICF). Furthermore, spinal plasticity was also assessed by means of homosynaptic FCR H-reflex depression (HD). LMT decreased HD and ICF. In contrast, VMT had no significant effect on cortical and spinal parameters. There was a nonsignificant tendency of an increase in MEP amplitudes after both interventions. This implies that human locomotor-related learning involves spinal mechanisms. Despite the decreasing importance of quadrupedal coordination in the course of evolution, these changes in transsynaptic plasticity may reflect a persisting locomotor memory-encoding function in the spinal circuitry of the human upper extremities. Evaluating FCR HD might be helpful for the evaluation and development of locomotor rehabilitation strategies.

Protein analysis through Western blot of cells excised individually from human brain and muscle tissue

Comparing protein levels from single cells in tissue has not been achieved through Western blot. Laser capture microdissection allows for the ability to excise single cells from sectioned tissue and compile an aggregate of cells in lysis buffer. In this study we analyzed proteins from cells excised individually from brain and muscle tissue through Western blot. After we excised individual neurons from the substantia nigra of the brain, the accumulated surface area of the individual cells was 120,000, 24,000, 360,000, 480,000, 600,000 μm2. We used an optimized Western blot protocol to probe for tyrosine hydroxylase in this cell pool. We also took 360,000 μm2 of astrocytes (1700 cells) and analyzed the specificity of the method. In muscle we were able to analyze the proteins of the five complexes of the electron transport chain through Western blot from 200 human cells. With this method, we demonstrate the ability to compare cell-specific protein levels in the brain and muscle and describe for the first time how to visualize proteins through Western blot from cells captured individually.

P4-10-07: Clinico-Pathologic Features of Breast Cancer Patients with Primary Metastatic Disease Versus Localized Disease: A Multicenter Study

Objective: Approximately 6% of breast cancer patients present with primary metastatic disease (pmBC) at first diagnosis. Clinicopathological differences to non-metastatic patients are undetermined.

Methods: Exploratory analysis of patients with pmBC treated in 8 breast cancer units between 1998 and 2010. Tumor characteristics of these patients were compared with non-metastatic breast cancer patients (BC) of one breast cancer center who had neither local-recurrence nor distant metastases during 30 months of follow-up after first diagnosis. Standard staging in patients with first diagnosis of BC included chest X-ray, abdominal ultrasonography and bone scan. Molecular subtypes were analyzed and defined by immunohistochemical markers (ER, PR, Her2-receptor).

Results: 2.214 patients were included, 1.642 with BC and 572 with pmBC, respectively. Patients with pmBC were 7 years older (BC 58 years of age vs. pmBC 65 years; p=0.000) and were more likely to be postmenopausal (74% vs. 83%; p=0.000). Most common localizations of distant first metastases were bone (61,5%), liver (24%), lung (21%) and non-axillary lymph nodes (12%).

85 (15%) patients with pmBC were diagnosed in stage T1. Factors associated with pmBC in multivariate analysis for this group were positive lymph node status (OR 3.4; 95%CI 2.3−6.0; p=0.000), grading 3 (OR 2.3; 95%CI 1.3−4.0; p=0.003), lobular histology (OR 2.3; 95%CI 1.2−4.5; p=0,010) and phenotype Luminal B (OR 2.4; 95%CI 1.25−5.0; p=0.014). 197 (34%) patients with pmBC were diagnosed in stage T2; positive lymph node status (OR 4.8; 95%CI 1.1−3.0; p=0.017) and grading 3 (OR 1.6; 95% CI 1.6−2.3; p=0.019) were reported as risk factors for this group. 90 (16%) and 200 (35%) patients were diagnosed with stages T3 and T4, respectively. In T3/4 tumors a positive lymph node status (OR 5.2; 95% CI 2.9−9.3; p=0.000) and grading 3 (OR 2.2; 95%CI 1.2−3.9; p=0.009) could be defined as significant risk factors for distant metastases. Postmenopausal status was associated with primary metastases in stage T2 (OR 1.8; 95%CI 1.2−2.9; p=0.008) and T3/4 (OR 2.4; 95%CI 1.2−4.7; p=0.011) but not in T1 tumors (OR 1.3; 95%CI 0.7−2.1; p=0.420). There was no association with hormone or Her2 receptor status nor with a specific phenotype for T2-4 tumors.

Conclusion: The clinico-pathological features of breast cancer patients with or without primary metastases differ. In all stages positive lymph node status and higher grading were associated with pmBC significantly. Lobular histology was reported as a risk factor for T1-2 compared to patients without metastases. This feature was not found for T3/4 pmBC. T1 pmBC were likely to be associated with luminal B phenotype. T3-4 pmBC have not been associated with any phenotype or hormone receptor constellation as risk factor for metastases. Tumor biology seems to play a minor role for risk of metastases in T3-4 stages compared to patients with T1-tumors. Findings from this analysis should be considered in the choice of staging methods, especially in stage T1.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-10-07.

The crossed leg sign indicates a favorable outcome after severe stroke

OBJECTIVE

We investigated whether crossed legs are a prognostic marker in patients with severe stroke.

METHODS

In this controlled prospective observational study, we observed patients with severe stroke who crossed their legs during their hospital stay and matched them with randomly selected severe stroke patients who did not cross their legs. The patients were evaluated upon admission, on the day of leg crossing, upon discharge, and at 1 year after discharge. The Glasgow Coma Scale, the NIH Stroke Scale (NIHSS), the modified Rankin Scale (mRS), and the Barthel Index (BI) were obtained.

RESULTS

Patients who crossed their legs (n = 34) and matched controls (n = 34) did not differ in any scale upon admission. At the time of discharge, the GCS did not differ, but the NIHSS was better in crossed legs patients (6.5 vs 10.6; p = 0.0026), as was the mRS (3.4 vs 5.1, p < 0.001), and the BI (34.0 vs 21.1; p = 0.0073). At 1-year follow-up, mRS (2.9 vs 5.1, p < 0.001) and the BI (71.3 vs 49.2; p = 0.045) were also better in the crossed leg group. The mortality between the groups differed grossly; only 1 patient died in the crossing group compared to 18 in the noncrossing group (p < 0.001).

CONCLUSION

Leg crossing is an easily obtained clinical sign and is independent of additional technical examinations. Leg crossing within the first 15 days after severe stroke indicates a favorable outcome which includes less neurologic deficits, better independence in daily life, and lower rates of death.

Determination of typical patterns from strongly varying signals

Forces measured in human joints vary considerably when an activity such as walking is carried out by different subjects or when it is repeated. 'Typical' standardised force-time patterns are needed to test and improve joint implants. Mechanically most important for their endurance are the magnitudes and times of force maxima and minima. They should equal the arithmetic means from the single measurements. Similar problems exist when evaluating other strongly varying signals, as in gait analysis. The new method to calculate typical signals (TSs) enhances existing dynamic time warping (DTW) procedures. It allows us to combine any number of signals. The sequence of input signals--used for calculating the TS--has only a minor influence. The accuracy of the method was tested numerically on signals for which the typical patterns could be defined exactly, and also on real joint forces that varied to different extents.

The effect of nintendo wii on balance: a pilot study supporting the use of the wii in occupational therapy for the well elderly

ABSTRACT This study explored the benefits that Nintendo's Wii Fit activities may have on the balance of 22 community living older adults. Over 4 weeks, participants completed twelve 20-min sessions using various programs in the Wii Fit. Pretest and posttest measurements were obtained using the Berg Balance Scale with participants scoring an average of 9.14 points higher on the postintervention. Posttest balance scores were significantly greater [t (21) = -9.861, p < .01] than pretest scores. Reports from the participants supported the positive use and possible improvements in quality of life. The results of this study suggest the potential effectiveness of utilizing the Nintendo Wii as a therapeutic agent in occupational therapy practice.

Characterization of sepsis pathogenesis using molecular biomarkers and drug treatments in the mouse CLP model (56.6)

Sepsis is a severe systemic disease caused by an uncontrolled immune response to an inflammatory stimulus. Sepsis has a high mortality rate and few successful treatments are available. Furthermore, one of the confounding aspects of sepsis treatment is the highly variable and dynamic manifestation of the disease. Thus, there is a need not only for new sepsis treatments but also for biomarkers of sepsis that may guide physicians in patient treatment. The cecal ligation and puncture model (CLP) is a clinically relevant model that replicates the nature of human sepsis after trauma as it has a focus of infection rather than a systemic initiation. Thus, we have chosen to characterize the CLP model and use it to evaluate candidate sepsis biomarkers and therapeutics. We evaluated a variety of potential biomarkers and correlated them with body temperature to determine which ones best reflect the health of the animal. Interestingly, some cytokines and blood chemistry markers highly correlated with health and bacterial load while others did not. To gain further insight into sepsis pathogenesis we tested drugs with differing mechanisms of action. A significant observation was that an antibiotic was highly efficacious while the immunosuppressive dexamethasone was not beneficial; suggesting that bacterial elimination is crucial for survival. In summary, our results suggest potential biomarkers for guiding sepsis treatment and provide insight into sepsis pathogenesis.

Creatine in mouse models of neurodegeneration and aging

The supplementation of creatine has shown a marked neuroprotective effect in mouse models of neurodegenerative diseases (Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis). This has been assigned to the known bioenergetic, anti-apoptotic, anti-excitotoxic and anti-oxidant properties of creatine. As aging and neurodegeneration share pathophysiological pathways, we investigated the effect of oral creatine supplementation on aging in 162 aged wild-type C57Bl/6J mice. The median healthy life span of creatine-fed mice was 9% higher than in their control littermates, and they performed significantly better in neurobehavioral tests. In brains of creatine-treated mice, there was a trend toward a reduction of reactive oxygen species and significantly lower accumulation of the "aging pigment" lipofuscin. Expression profiling showed an upregulation of genes implicated in neuronal growth, neuroprotection, and learning. These data showed that creatine improves health and longevity in mice. Creatine may, therefore, be a promising food supplement to promote healthy human aging. However, the strong neuroprotective effects in animal studies of creatine have not been reproduced in human clinical trials (that have been conducted in Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis). The reasons for this translational gap are discussed. One obvious cause seems to be that all previous human studies may have been underpowered. Large phase III trials over long time periods are currently being conducted for Parkinson's disease and Huntington's disease, and will possibly solve this issue.

Loading of the knee joint during activities of daily living measured in vivo in five subjects

Detailed knowledge about loading of the knee joint is essential for preclinical testing of implants, validation of musculoskeletal models and biomechanical understanding of the knee joint. The contact forces and moments acting on the tibial component were therefore measured in 5 subjects in vivo by an instrumented knee implant during various activities of daily living. Average peak resultant forces, in percent of body weight, were highest during stair descending (346% BW), followed by stair ascending (316% BW), level walking (261% BW), one legged stance (259% BW), knee bending (253% BW), standing up (246% BW), sitting down (225% BW) and two legged stance (107% BW). Peak shear forces were about 10-20 times smaller than the axial force. Resultant forces acted almost vertically on the tibial plateau even during high flexion. Highest moments acted in the frontal plane with a typical peak to peak range -2.91% BWm (adduction moment) to 1.61% BWm (abduction moment) throughout all activities. Peak flexion/extension moments ranged between -0.44% BWm (extension moment) and 3.16% BWm (flexion moment). Peak external/internal torques lay between -1.1% BWm (internal torque) and 0.53% BWm (external torque). The knee joint is highly loaded during daily life. In general, resultant contact forces during dynamic activities were lower than the ones predicted by many mathematical models, but lay in a similar range as measured in vivo by others. Some of the observed load components were much higher than those currently applied when testing knee implants.

Proteochemometric modeling as a tool to design selective compounds and for extrapolating to novel targets

Proteochemometric modeling is founded on the principles of QSAR but is able to benefit from additional information in model training due to the inclusion of target information.

Realistic loads for testing hip implants

The aim here was to define realistic load conditions for hip implants, based on in vivo contact force measurements, and to see whether current ISO standards indeed simulate real loads. The load scenarios obtained are based on in vivo hip contact forces measured in 4 patients during different activities and on activity records from 31 patients. The load scenarios can be adapted to various test purposes by applying average or high peak loads, high-impact activities or additional low-impact activities, and by simulating normal or very active patients. The most strenuous activities are walking (average peak forces 1800 N, high peak forces 3900 N), going up stairs (average peak forces 1900 N, high peak forces 4200 N) and stumbling (high peak forces 11,000 N). Torsional moments are 50% higher for going up stairs than for walking. Ten million loading cycles simulate an implantation time of 3.9 years in active patients. The in vitro fatigue properties of cementless implant fixations are exceeded during stumbling. At least for heavyweight and very active subjects, the real load conditions are more critical than those defined by the ISO standards for fatigue tests.

A descriptive study of a specialized worker's psychological trauma program

BACKGROUND

Psychological trauma in the workplace is gaining recognition as an important cause of workplace disability but little is known about the workers who are affected. The Psychological Trauma Program (PTP) in Toronto (Canada) is a specialized provincial worker's compensation board assessment program for workers with psychological sequelae of workplace trauma.

AIMS

To characterize workers presenting to the PTP in terms of demographic, occupational, traumatic exposure and diagnostic variables.

METHODS

A retrospective secondary analysis of all workers referred to the PTP for assessment within 1 year of traumatic event between 1999 and 2006.

RESULTS

Five hundred and thiry-one referred workers were included in the study. Most workers were working-age male (76%), married (65%) and labourers (43%). Nearly half were born outside Canada. Post-traumatic stress disorder was the primary diagnosis in 44%. Fifty-eight percent had one or more secondary diagnoses. For just over half of the workers, the traumatic event resulted in a permanent physical impairment.

CONCLUSIONS

Specialist referral may be indicated for workers experiencing prolonged recovery following workplace trauma. Male workers and those with co-morbidities or permanent injuries may be more likely to require referral. Individualized treatment approaches are likely important; however, more research is needed to guide future interventions.