Study on the mechanistic classes of fluorescence quenching of tryptanthrin-malononitrile adduct by aniline

Mechanistic studies of the fluorescence quenching of 2-(2-chloro-12-oxoindolo[2,1-b]quinazolin-6(12H)-ylidene)malononitrile (2CTMA) with aniline, using solvent mixtures of acetonitrile and 1,4-dioxane at room temperature, by steady-state and time-resolved methods is reported here. It was confirmed that, with the use of the sphere of action static quenching model and finite sink approximation model, that the bimolecular quenching reactions are due to the presence of both dynamic and static quenching processes.

Human Head and Helmet Interface Friction Coefficients with Biological Sex and Hair Property Comparisons

Dummy headforms used for impact testing have changed little over the years, and frictional characteristics are thought not to represent the human head accurately. The frictional interface between the helmet and head is an essential factor affecting impact response. However, few studies have evaluated the coefficient of friction (COF) between the human head and helmet surface. This study's objectives were to quantify the human head's static and dynamic COF and evaluate the effect of biological sex and hair properties. Seventy-four participants slid their heads along a piece of helmet foam backed by a fixed load cell at varying normal force levels. As normal force increased, static and dynamic human head COF decreased following power-law curves. At 80 N, the static COF is 0.32 (95% CI 0.30-0.34), and the dynamic friction coefficient is 0.27 (95% CI 0.26-0.28). Biological sex and hair properties were determined not to affect human head COF. The COFs between the head and helmet surface should be used to develop more biofidelic head impact testing methods, define boundary conditions for computer simulations, and aid decision-making for helmet designs.

Tryptanthrin-malononitrile adduct for highly efficient turn-off fluorescent sensing of aniline

The fluorescence quenching of 2-(8-chloro-12-oxo-12H-indolo[2,1-b]quinazolin-6-ylidene)-malononitrile (5a) by aniline was studied in detail. Time correlated single photon counting measurements (TCSPC) indicated that the quenching involved both static and dynamic mechanisms without ground state complex formation. The selectivity towards aniline sensing in presence of other amines/aromatics and the anti-interference studies together with the low LOD value indicates the potential of 5a as a molecular probe for aniline sensing which is unaffected by pH alteration as well.

Blocking toll-like receptor 4 mitigates static loading induced pro-inflammatory expression in intervertebral disc motion segments

While the anabolic effects of mechanical loading on the intervertebral disc (IVD) have been extensively studied, inflammatory responses to loading have not been as well characterized. Recent studies have highlighted a significant role of innate immune activation, particularly that of toll-like receptors (TLRs), in IVD degeneration. Biological responses of intervertebral disc cells to loading depend on many factors that include magnitude and frequency. The goals of this study were to characterize the inflammatory signaling changes in response to static and dynamic loading of IVD and investigate the contributions of TLR4 signaling in response to mechanical loading. Rat bone-disc-bone motion segments were loaded for 3 hr under a static load (20 % strain, 0 Hz) with or without an additional low-dynamic (4 % dynamic strain, 0.5 Hz) or high-dynamic (8 % dynamic strain, 3 Hz) strain, and results were compared to unloaded controls. Some samples were also loaded with or without TAK-242, an inhibitor of TLR4 signaling. The magnitude of NO release into the loading media (LM) was correlated with the applied frequency and strain magnitudes across different loading groups. Injurious loading profiles, such as static and high-dynamic, significantly increased Tlr4 and Hmgb1 expression while this result was not observed in the more physiologically relevant low-dynamic loading group. TAK-242 co-treatment decreased pro-inflammatory expression in static but not dynamic loaded groups, suggesting that TLR4 plays a direct role in mediating inflammatory responses of IVD to static compression. Overall, the microenvironment induced by dynamic loading diminished the protective effects of the TAK-242, suggesting that TLR4 plays a direct role in mediating inflammatory responses of IVD to static loading injury.

Evaluation of financing efficiency of strategic emerging industries in the context of green development: evidence from China

Strategic emerging industries are key areas to transform the traditional industrial model of high pollution, high energy consumption, and high emissions. This paper focuses on the measurement of financing efficiency of strategic emerging industries. On the one hand, in order to overcome the interference of external environment and statistical error existing in the traditional single data envelope model, the SSBM-BOOT five-stage model is proposed. On the other hand, Malmquist index method and Luenberger productivity method are combined to evaluate dynamic efficiency, which select Beijing-Tianjin-Hebei listed companies' data. The results show that (1) external environmental factors play a significant role in financing efficiency. The empirical results of the SSBM-BOOT five-stage model show that environmental factors "raise" the efficiency value of the whole Beijing-Tianjin-Hebei region. (2) Based on the revised data and the overall and decomposition results of SBM-ML index, it can be seen that the regional industry is still in the stage of scale expansion, and the financing efficiency depends on technological innovation that needs to be improved. Finally, the paper puts forward the concrete strategies of creating industrial development environment, promoting technological innovation, and establishing green investment and financing mechanism.

Digital Cytology in Exotic Practice: Tips to Optimize Diagnosis

Digitization has enhanced the utility of cytology in private practice by allowing for rapid sample receipt and analysis, leading to better informed real-time patient care. Despite many advantages of digital cytology, understanding its limitations is required to avoid common pitfalls. A strong foundation in sample preparation and imaging techniques is also required to obtain high-quality diagnostic samples. By optimizing these factors, the benefits of digital cytology are maximized, allowing for the practice of high-quality point-of-care medicine that best addresses the needs of the patient and pet owner in a rapid time frame.

Static and temporal dynamic changes of intrinsic brain activity in pediatric and adults OCD

Epidemiological and clinical age differences in obsessive-compulsive disorder (OCD) have been reported in clinical symptoms and morphometry changes; however, age differences in amplitude of low-frequency fluctuation and the relationship between ALFF imaging and clinical symptoms has not been thoroughly studied in OCD. Age may be an important feature associated with distinct subtypes of OCD. To examine the effect of age on OCD, the current study enrolled 92 OCD patients (32 pediatrics and 60 adults) and matched HCs (33 pediatrics and 84 adults), undergoing resting-state functional magnetic resonance imaging. The spontaneous brain activity was measured by static and dynamic amplitude of low-frequency fluctuation (ALFF) followed by two-way ANOVA. In pediatric OCD patients versus adult patients, we observed a significantly higher ALFF in the default mode network (DMN), including posterior cingulate, precuneus and superior frontal gyrus, and extending to cuneus, lingual gyrus. Additionally, the increased ALFF and dynamic ALFF in the precentral gyrus were found in pediatric patients. In OCD patients compared with controls, we found a significantly increased ALFF in hippocampal gyrus, cerebellum network (CN), and the dALFF in middle and inferior occipital gyrus, bilateral paracentral lobule and sensorimotor network. The findings emphasized the different patterns of static and dynamic intrinsic brain activity alterations associated with pediatric and adult OCD patients. These results provide unique insights into constructing evidenced-based distinct OCD subtypes based on brain activity and point the need of specified management for pediatric and adult OCD patients in clinical setting.

Naltrexone promotes mechanical allodynia in humans and rats

Mechanical allodynia has been studied in chronic naltrexone-treated people (N.T.P.) and rats (N.T.R.). After persistent naltrexone administration, patients acquired static and dynamic mechanical allodynia, as measured by von Frey filament (vFf) and brush stimulations. Pregabalin and levodopa administrations in N.T.P. significantly reduced allodynic behaviour, albeit these molecules did not completely stop it. As evidenced by the deployment of the vFf, subchronic treatment with Naltrexone delivered peripherally or intrathecally induced allodynic behaviour in rats. Increased expressions of two pain markers, pERK1/2 and PKCγ, in the spinal dorsal horn laminae were associated with naltrexone-induced allodynic behaviour. After vFf stimulation, pERK1/2 expression was substantially higher (p < 0.001) in superficial spinal dorsal horn laminae than in non-stimulated or naive non-stimulated rats. In addition, when compared to control rats, N.T.R. showed a substantial (p < 0.001) increase in PKCγ expression. PKCγ expression was found to be strong in lamina IIi and laminae III-IV. A cellular mechanism is proposed for the naltrexone effect. In both people and rats, Naltrexone induces static mechanical allodynia, according to this study.

A Simple 96-Well Plate-Based Method for Development of Candida Biofilms Under Static Conditions

We describe a rapid and simple in vitro method for development of Candida biofilms under static growth conditions. This 96-well microtiter-based method measures metabolic activity of sessile cells and can also be easily adapted for antifungal susceptibility testing. The entire procedure takes 2-3 days to complete, reliably quantifies biofilms, and provides reproducible results that are imperative toward the standardization of antifungal susceptibility testing of biofilms.

A Dynamic Approach to Cycling Biomechanics

Cycling biomechanics is a complex analysis of the cyclist and the bicycle. It is important to assess the cyclist dynamically because kinematics and muscle patterns are influenced by their type of riding and fatigue and intensity. Intrinsic factors such as anthropometrics and flexibility should guide the initial bicycle configuration. Static kinematics are a valid and reliable tool in the process of bike fitting, providing an initial fast and cost-effective method of assessing the cyclist. Dynamic assessment methods should then be used to fine tune the bicycle configuration according to the specific needs and workloads of the cyclist.

Cardiovascular responses to dynamic and static upper-body exercise in a cold environment in coronary artery disease patients

Purpose

Upper-body exercise performed in a cold environment may increase cardiovascular strain, which could be detrimental to patients with coronary artery disease (CAD). This study compared cardiovascular responses of CAD patients during graded upper-body dynamic and static exercise in cold and neutral environments.

Methods

20 patients with stable CAD performed 30 min of progressive dynamic (light, moderate, and heavy rating of perceived exertion) and static (10, 15, 20, 25 and 30% of maximal voluntary contraction) upper body exercise in cold (− 15 °C) and neutral (+ 22 °C) environments. Heart rate (HR), blood pressure (BP) and electrocardiographic (ECG) responses were recorded and rate pressure product (RPP) calculated.

Results

Dynamic-graded upper-body exercise in the cold increased HR by 2.3–4.8% (p = 0.002–0.040), MAP by 3.9–5.9% (p = 0.038–0.454) and RPP by 18.1–24.4% (p = 0.002–0.020) when compared to the neutral environment. Static graded upper-body exercise in the cold resulted in higher MAP (6.3–9.1%; p = 0.000–0.014), lower HR (4.1–7.2%; p = 0.009–0.033), but unaltered RPP compared to a neutral environment. Heavy dynamic exercise resulted in ST depression that was not related to temperature. Otherwise, ECG was largely unaltered during exercise in either thermal condition.

Conclusions

Dynamic- and static-graded upper-body exercise in the cold involves higher cardiovascular strain compared with a neutral environment among patients with stable CAD. However, no marked changes in electric cardiac function were observed. The results support the use of upper-body exercise in the cold in patients with stable CAD.

Trial registration

Clinical trial registration NCT02855905 August 2016.

Real-time versus static scoring in musculoskeletal ultrasonography in patients with inflammatory hand osteoarthritis

Objectives

Agreement between real-time and static ultrasonography has not been studied in musculoskeletal diseases. We studied this agreement in inflammatory hand OA.

Methods

Ultrasonography was performed blinded to clinical information of 30 joints of 75 patients with hand OA, treated with prednisolone in a randomized placebo-controlled double-blind trial. Images were scored real-time at acquisition and stored images were scored static (paired in known chronological order) for inflammatory features and osteophytes (score 0–3). Agreement between methods was studied at joint level with quadratic weighted kappa. At patient level intra-class correlations (ICC) of sum scores and change in sum-scores (delta baseline—week 6) were calculated. Responsiveness of scoring methods was analysed with generalized estimating equations (GEE) with treatment as independent and ultrasonography findings as dependent variable.

Results

Agreement at baseline was good to excellent at joint level (kappa 0.72–0.88) and moderate to excellent at patient level (ICC 0.58–0.91). Agreement for change in sum scores was poor to fair for synovial thickening and effusion (ICC 0.18 and 0.34, respectively), while excellent for Doppler signal (ICC 0.80). Real-time ultrasonography discriminated between prednisolone and placebo with a mean between-group difference of synovial thickening of −2.5 (95% CI: −4.7, −0.3). Static ultrasonography did not show a decrease in synovial thickening.

Conclusion

While cross-sectional agreement between real-time and static ultrasonography is good, static ultrasonography measurement of synovial thickening did not show responsiveness to prednisone therapy while real-time ultrasonography did. Therefore, when ultrasonography is used in clinical trials, real-time dynamic scoring should remain the standard for now.

No pressure, no diamonds? - Static vs. dynamic compressive in-situ loading to evaluate human articular cartilage functionality by functional MRI

Biomechanical Magnetic Resonance Imaging (MRI) of articular cartilage, i.e. its imaging under loading, is a promising diagnostic tool to assess the tissue's functionality in health and disease. This study aimed to assess the response to static and dynamic loading of histologically intact cartilage samples by functional MRI and pressure-controlled in-situ loading. To this end, 47 cartilage samples were obtained from the medial femoral condyles of total knee arthroplasties (from 24 patients), prepared to standard thickness, and placed in a standard knee joint in a pressure-controlled whole knee-joint compressive loading device. Cartilage samples' responses to static (i.e. constant), dynamic (i.e. alternating), and no loading, i.e. free-swelling conditions, were assessed before (δ₀), and after 30 min (δ₁) and 60 min (δ₂) of loading using serial T1ρ maps acquired on a 3.0T clinical MRI scanner (Achieva, Philips). Alongside texture features, relative changes in T1ρ (Δ₁, Δ₂) were determined for the upper and lower sample halves and the entire sample, analyzed using appropriate statistical tests, and referenced to histological (Mankin scoring) and biomechanical reference measures (tangent stiffness). Histological, biomechanical, and T1ρ sample characteristics at δ₀ were relatively homogenous in all samples. In response to loading, relative increases in T1ρ were strong and significant after dynamic loading (Δ₁ = 10.3 ± 17.0%, Δ₂ = 21.6 ± 21.8%, p = 0.002), while relative increases in T1ρ after static loading and in controls were moderate and not significant. Generally, texture features did not demonstrate clear loading-related associations underlying the spatial relationships of T1ρ. When realizing the clinical translation, this in-situ study suggests that serial T1ρ mapping is best combined with dynamic loading to assess cartilage functionality in humans based on advanced MRI techniques.

Long-term follow-up of the three-ligament tenodesis for scapholunate ligament lesions: 9-year results

We report on a retrospective cohort of 50 cases of three-ligament tenodesis for scapholunate instability. Fifteen cases (30% of our cohort) needed salvage surgery (11 proximal row carpectomies, 2 partial and 2 total wrist fusions) at an average of 33 months and are considered "failures". Of the 35 remaining cases ("success"), 16 (32% of our cohort) were reviewed at average 111 months and had good functional outcomes (QuickDASH 18/100, PRWE 11/100, pain 1/10, satisfaction 9/10). Return to work was 81% and grip strength was 80% of the opposite side. Radiological review found no significant correction in the short-term: scapholunate angle (SLA) from 72° to 69° (p = 0.544), scapholunate distance (SLD) from 3.4 mm to 3.4 mm (p = 0.833) and radiolunate angle (RLA) from 17° to 13° (p = 0.253). A significant deterioration in SLA from 72° to 80° (p = 0.014), not correlated to function, was seen at final follow-up. Radiographic progression to wrist degeneration was seen in 63% of successful cases. In failed cases, we noticed inferior radiographic parameters in the short-term: SLD of 4.6 mm in failed versus 3.4 mm in successful cases (p = 0.038) and RLA of 22° in failed versus 13° in successful cases (p = 0.046). Complication rate was 10% (2 scaphoid necroses, 1 septic arthritis and 2 complex regional pain syndromes). Despite radiological deterioration of SLA and development of degeneration in most cases, three-ligament tenodesis can give satisfactory wrist function in some patients, but we observed a significant number of failures and a high complication rate. LEVEL OF EVIDENCE: IV.

Connective profiles and antagonism between dynamic and static connectivity underlying generalized epilepsy

This study aims to characterize the connective profiles and the coupling relationship between dynamic and static functional connectivity (dFC and sFC) in large-scale brain networks in patients with generalized epilepsy (GE). Functional, structural and diffuse MRI data were collected from 83 patients with GE and 106 matched healthy controls (HC). Resting-state BOLD time course was deconvolved to neural time course using a blind hemodynamic deconvolution method. Then, five connective profiles, including the structural connectivity (SC) and BOLD/neural time course-derived sFC/dFC networks, were constructed based on the proposed whole brain atlas. Network-level weighted correlation probability (NWCP) were proposed to evaluate the association between dFC and sFC. Both the BOLD signal and neural time course showed highly concordant findings and the present study emphasized the consistent findings between two functional approaches. The patients with GE showed hypervariability and enhancement of FC, and notably decreased SC in the subcortical network. Besides, increased dFC, weaker anatomic links, and complex alterations of sFC were observed in the default mode network of GE. Moreover, significantly increased SC and predominantly increased sFC were found in the frontoparietal network. Remarkably, antagonism between dFC and sFC was observed in large-scale networks in HC, while patients with GE showed significantly decreased antagonism in core epileptic networks. In sum, our study revealed distinct connective profiles in different epileptic networks and provided new clues to the brain network mechanism of epilepsy from the perspective of antagonism between dynamic and static functional connectivity.

Customized intraoperatively molded articulating cement spacers for two-stage revisions TKA with major bone defects

BACKGROUND

The use of articulating spacers, molded or prefabricated, becomes difficult in case of severe bone losses. Our idea was to customize the Molded Articulating Cement Spacers with cement stem extensions and if necessary metaphyseal cement augmentations in order to use them also in case of major bone defects.

METHODS

Fifty-four knees in fifty-three patients undergoing 2-stage exchange arthroplasty were divided in 4 groups, treated with 4 different types of spacers (Static, articulating molded, customized molded and metal on Poly) and evaluated in terms of Range of Motion (ROM), Knee Society Score (KSS), patients' related outcome measures (PROMs), rate of complication and ease of the surgical exposure at the time of reimplantation.

RESULTS

At final follow-up, no statistical differences in terms of ROM and KSS were found between the articulating groups. Static Spacers showed statistically significant lower results both in terms of ROM and KSS comparing to the other 3 groups (P < 0.05). Considering PROMs, statistically better outcomes for all articulating spacers were found both when spacer was in place and at final follow-up comparing to the static spacers group (P < 0.05). No statistically significant difference was found between the 3 articulating spacers groups. Radiographic analysis did not show signs of loosening, migration or major bone loss.

CONCLUSIONS

Customized Intraoperatively Molded Articulating Cement Spacers are a safe solution for two-stage revisions TKA with major bone defects and may provide a better quality of life for patients when in place comparing to static ones.

Static and dynamic alterations in the amplitude of low-frequency fluctuation in patients with amyotrophic lateral sclerosis

Background

Static changes in local brain activity in patients suffering from amyotrophic lateral sclerosis (ALS) have been studied. However, the dynamic characteristics of local brain activity are poorly understood. Whether dynamic alterations could differentiate patients with ALS from healthy controls (HCs) remains unclear.

Methods

A total of 54 patients with ALS (mean age = 48.71 years, male/female = 36/18) and 54 (mean age = 48.30 years, male/female = 36/18) HCs underwent magnetic resonance imaging scans. To depict static alterations in cortical activity, amplitude of low-frequency fluctuations (ALFF) which measures the total power of regional activity was computed. Dynamic ALFF (d-ALFF) from all subjects was calculated using a sliding-window approach. Statistical differences in ALFF and d-ALFF between both groups were used as features to explore whether they could differentiate ALS from HC through support vector machine method.

Results

In contrast with HCs, patients with ALS displayed increased ALFF in the right inferior temporal gyrus and bilateral frontal gyrus and decreased ALFF in the left middle occipital gyrus and left precentral gyrus. Furthermore, patients with ALS demonstrated lower d-ALFF in widespread regions, including the right lingual gyrus, left superior temporal gyrus, bilateral precentral gyrus, and left paracentral lobule by comparison with HCs. In addition, the ALFF in the left superior orbitofrontal gyrus had a tendency of correlation with ALSFRS-R score and disease progression rate. The classification performance in distinguishing ALS was higher with both features of ALFF and d-ALFF than that with a single approach.

Conclusions

Decreased dynamic brain activity in the precentral gyrus, paracentral gyrus, lingual gyrus, and temporal regions was found in the ALS group. The combined ALFF and d-ALFF could distinguish ALS from HCs with a higher accuracy than ALFF and d-ALFF alone. These findings may provide important evidence for understanding the neuropathology underlying ALS.

Does static trunk motion analysis reflect its true position during daily activities in adolescent with idiopathic scoliosis?

INTRODUCTION

Adolescent idiopathic scoliosis is common condition in pediatric orthopedics that is generally analyzed with standard radiographs. However, the conditions under which the radiographs are made are completely different than the position that patients use during day-to-day activities. We hypothesized that the trunk's static position differs from its dynamic one. The aim of this study was to determine differences between the trunk's static and dynamic positions using motion analysis in adolescents with idiopathic scoliosis.

PATIENTS AND METHODS

This prospective, single-center study enrolled adolescents with idiopathic scoliosis who were scheduled to undergo surgical correction. The day before the surgery, radiographs were made and motion analysis was performed (static and dynamic acquisitions). Various parameters were measured on the radiographs and motion analysis, including the coronal vertical axis (CVA), sagittal vertical axis (SVA) and coronal shoulder tilt.

RESULTS

The study enrolled 62 patients with a mean age of 15.5 years. There was a significant correlation between the radiographic measurements and the static motion analysis results for most parameters. Conversely, dynamic measurements of CVA, SVA and coronal shoulder tilt were not correlated to their static measurements (R=0.229; 0.198 and -0.109 respectively, all p>0.05). The static coronal shoulder tilt was opposite to the one found during walking (-0.9° vs. 0.5°, p=0.031).

DISCUSSION

Our study is the first to compare the trunk's static position with its dynamic position during walking in a cohort of adolescents with idiopathic scoliosis. Motion analysis provides new information about the trunk's dynamic positions. Based on our findings, radiographic analysis only partially captures the spinal alignment and cannot be used to draw reliable conclusions about the trunk's dynamic balance.

A comparison of the length and width of static inked two-dimensional bare footprints found on a hard compared to a soft surface

In forensic intelligence-gathering it would be useful to evaluate if there are differences between static inked bare footprints captured on hard surfaces compared to soft surfaces. This was undertaken using samples from 30 undergraduate students. Initially a static footprint was taken for each participant on a hard surface and this was followed by a static footprint on a soft surface. On both occasions, the participants stood on an inkless mat and then on reactive paper, creating a two-dimensional print. The Reel method was used to analyse each footprint and the print was measured to see whether a difference existed between length and width (forefoot and rearfoot width) on a hard surface compared to a soft surface. The conclusion from this study was there is a statistically significant increase in length and width of a static bare footprint on a soft surface as opposed to a hard surface. If a forensic footprint examiner compares static bare footprints found on a soft surface and compares them to a static bare footprint of the same foot taken later, then the increase in both length and width of the footprints on a soft surface should be considered in the evaluation.

Static pressures, intra-access blood flow and dynamic Kt/V profiles in the prediction of dialysis access function

BACKGROUND

Hemodialysis machine-generated circuit pressures and clearance profiles are potential predictors of quality assurances. In our practice, we previously we observed that elevated static access pressures were associated with abnormal Kt/V values, high access recirculation and deviation of the Kt/V profile (Abnormal Kt/V profile) from normally expected values (Normal Kt/V profile).

AIM

To hypothesize that static or derived access pressures would correlate with direct intra-access blood flow rates and that clearance (Kt/V) profiles would correlate with measured Kt/V values.

METHODS

Static access pressures, real-time adequacy of dialysis and intra-access blood flow were investigated in end stage renal disease patients undergoing hemodialysis. Wilcoxon-Mann-Whitney test, chi-square test or Fisher’s exact test was used to investigate differences between the groups; Spearman’s rank correlation test to investigate relationships between static pressures, direct intra-access pressures and Kt/V profiles; and multinomial logistic regression models to identify the independent effect of selected variables on Kt/V profiles. Odds ratio were calculated to measure the association between the variables and Kt/V profiles.

RESULTS

One hundred and seven patients were included for analysis. There were no significant differences between genders, and types of vascular access between the normal vs. abnormal clearance (Kt/V) profile groups. No significant correlation could be demonstrated between static access pressures and Kt/V profiles, static access pressures and intra-access blood flow, intra-access blood flow and Kt/V profiles, measured Kt/V and Kt/V profiles or recirculation and Kt/V profiles.

CONCLUSION

In this study utilizing measured versus estimated data, we could not validate that dialysis machine generated elevated static pressures predict intra-access blood flow disturbances or that abnormal Kt/V profiles predict access recirculation or inadequate dialysis. These parameters, though useful estimates, cannot be accepted as quality assurance for dialysis adequacy or access function without further evidences.

Burden of Treatment Compliance as an Impairment Rating Metric

All editions of the American Medical Association (AMA) guides rate impairment based on static deviations from population or personal norms in addition to rating based on interferences in activities of daily living (ADLs). The burden of treatment compliance (BOTC) method of impairment rating was developed as a stand-alone model to help overcome difficulties when rating internal medicine conditions, when normative metrics may be lacking and impacts on ADLs are not readily determined. With the sixth edition of the AMA guides, the BOTC model has been adapted to provide alternative operational metrics for functional losses associated with these conditions.

Estimating actual foot size from a static bare foot print in a White British Population

In forensic intelligence-gathering it would be useful to be able to estimate the size of a perpetrator's foot from a standing bare footprint found at the scene of crime. Currently, the advice is to add a fixed amount to the length of the footprint (typically 1.5 or 2.0 cm), but there is little evidence for this approach. This study used measured footprint and actual foot lengths from 146 participants from the white British student population of a University in the UK. Data were analysed using multiple regression with foot length as the dependent (outcome) variable and footprint length and sex as the independent variable/factor respectively. Sex was not a significant predictor. The regression equation for the best estimate of the foot length is 19.89 + 0.95 × print length ± 8 mm.

Dynamic evaluation of simulated leg length inequalities and their effects on the musculoskeletal apparatus

BACKGROUND

Leg length inequalities (LLI) are a common problem in medicine. So far, the diagnosis and treatment are performed under static conditions. Surface Topography (ST) is an optical, non-invasive technique that uses the principle of triangulation to measure spinal posture and pelvic position. This technique offers the opportunity to detect and treat LLIs and their effects under dynamic conditions.

RESEARCH

question The aim of the study is to show that ST can detect simulated LLIs under dynamic conditions and to prove if there are differences between the effects on the human body under static and dynamic conditions.

METHODS

In the clinical study a total of 30 test subjects were examined with a ST measuring device. LLIs (1 to 4 cm) were simulated using a custom- built sandal and insoles of various thickness. The pelvic obliquity, the surface rotation and lateral deviation of the spine were detected on a treadmill under static and dynamic conditions (3 km/h).

RESULTS

Under static and dynamic conditions LLIs lead to a significant increase of all measured parameters. The pelvic obliquity reaches a significant level of p < 0.0001 under static and p = 0.0001-0.0421 under dynamic conditions. However, for all examined parameters the magnitudes of the parameters under dynamic conditions were smaller than under static conditions.

SIGNIFICANCE

The study showed that simulated LLIs also have a significant effect on the human pelvis and spine under dynamic conditions, but with a smaller magnitude than under static conditions. The human individuum is a dynamic one. Because of that, for the future it should be of great interest to use dynamic measurements to detect and treat LLIs to provide an over correction of LLIs.

A comparative study of standing fleshed foot and walking and jumping bare footprint measurements

Approximating true fleshed foot length and forefoot width from crime scene footprints is primarily based on anecdotal observations and fails to consider effects of different dynamic activities on footprint morphology. A literature search revealed numerous variables influencing footprint formation including whether the print was formed statically or dynamically. The aim of this study was to investigate if length and width measurements of the fleshed foot differ to the same measurements collected from walking and jumping footprints. Measurements of standing right foot length and forefoot width were collected from thirteen participants. Walking and jumping right footprints were then obtained using an Inkless Shoeprint Kit and digitally measured with GNU Image Manipulation Programme. Descriptive analysis compared standing fleshed foot length and forefoot width against the same measurements taken from walking and jumping footprints with and without ghosting. Results suggested walking footprint length with ghosting (x¯ = 268.61 mm) was greater than standing fleshed foot length (x¯ = 264.3 mm) and jumping footprint length with ghosting (x¯ = 261.57 mm). However, standing fleshed foot length was found to be greater than walking (x¯ = 254.85 mm) or jumping (x¯ = 255.63 mm) footprint lengths without ghosting. Forefoot widths showed standing fleshed foot width (x¯ = 105.66 mm) was greater than walking (x¯ = 95.63 mm) or jumping (x¯ = 98.03 mm) footprint widths. This study identifies variation in measurements of the standing fleshed foot and those of walking and jumping footprints, including variability between different dynamic states.

Assessing bone quality through mechanical properties in postmenopausal trabecular bone

BACKGROUND

The inner structure of trabecular bone is a result of structural optimization provided by remodeling processes. Changes in hormonal status related to menopause cause bone tissue loss and micro-architectural deterioration with a consequent susceptibility to fracture. Accumulation of micro-damage in bone, as a function of the rate of production and rate of repair, underlies the development of stress fractures, increasing fragility associated to age and osteoporosis, especially in transmenopausal women.

PATIENTS AND METHODS

Quasi-static and nano-dynamic mechanical characterization were undertaken in trabecular bone from femoral neck biopsies of postmenopausal women. AFM (Atomic Force Microscopy) complementary studies were performed to determine nano-roughness (SRa) and the fibrils width of collagen. Nanoindentations were used to quantify transmenopausal changes in intrinsic mechanical properties of trabecular bone: hardness (Hi), modulus of Young (Ei), complex modulus (E*), tan delta (δ), storage modulus (E') and loss modulus (E").

RESULTS

As result of the quasi-static measurements, 0.149 (0.036) GPa and 2.95 (0.73) GPa of Hi and Ei were obtained, respectively. As result of the nano-dynamic measurements, 17.94 (3.15), 0.62 (0.10), 13.79 (3.21 and 6.39 (1.28) GPa of E*, tan (δ), E' and E" were achieved, respectively. 101.07 SRa and 831.28 nm of fibrils width were additionally obtained.

CONCLUSIONS

This study poses a first approach to the measurement of bone quality in postmenopausal trabecular bone by combining quasi-static, nano-DMA analysis and tribology of dentin surface through AFM characterization.

Gender differences in postural control in people with nonspecific chronic low back pain

BACKGROUND

Many studies have reported that there are several differences between genders which may result in altered neuromuscular control. Although the existing evidence suggests that low back pain (LBP) affects the ability to control posture, there is little evidence the gender differences in postural control in people with nonspecific chronic LBP.

RESEARCH QUESTION

Are there any gender differences in postural control and correlations between postural control, pain, disability, and fear of movement in people with nonspecific chronic LBP?

METHODS

Static and dynamic postural control were evaluated using a computerized postural control assessment tool including assessments for limits of stability (LOS), unilateral stance, and modified clinical test of sensory interaction on balance. Pain intensity and fear of movement were assessed using a visual analogue scale and the Tampa Scale of Kinesiophobia, respectively.

RESULTS

This cross-sectional study included 51 people (25 females and 26 males) with nonspecific chronic LBP. Mean reaction time in the LOS test was significantly less in male participants compared with females when adjusted for pain intensity and disability level, F(1,45) = 4.596, p = .037, ηp² = 0.093. There was no significant difference in the remaining LOS variables as well as unilateral stance, and modified clinical test of sensory interaction on balance variables between the genders (p > .05). Many correlations were observed between the LOS variables, pain intensity, and Tampa Scale of Kinesiophobia score in female participants (p < .05). The Tampa Scale of Kinesiophobia score was also correlated with the movement velocity and endpoint excursion in the LOS test in the male participants (p < .05).

SIGNIFICANCE

This study suggests that there is no difference in most of the static and dynamic postural control variables between females and males; however, higher fear of movement, and pain intensity during activity are more associated with impaired dynamic balance in females with nonspecific chronic LBP.

The effect of a maternity support belt on static stability and posture in pregnant and non-pregnant women

PURPOSE

Physical and hormonal changes during pregnancy are thought to affect balance and injury risk, with increased numbers of falls being reported. A maternity support belt (MSB) has been suggested to stabilize the pelvis and to enhance balance. The purpose of this study was therefore to investigate the effect of an MSB on postural stability in different trimesters of pregnancy.

METHODS

Postural stability was assessed in the first (T1, n = 30), second (T2, n = 30) and third trimester (T3, n = 30) of pregnancy and compared to non-pregnant controls (n = 30), using a portable force plate. Postural sway during quiescent standing with and without applying an MSB was characterized by analyzing path length, velocity, amplitudes and area. Subsequently, anterior and posterior limits of stability (LoS) were determined.

RESULTS

Postural sway during quiescent standing did not change with pregnancy. However, LoS performance was reduced already in T1, before body mass significantly increased. The MSB led to a small improvement in the LoS while slightly increasing postural sway in anterior-posterior direction and shifting the center of pressure posteriorly during quiescent standing.

CONCLUSION

While impairments in balance already occurred early in pregnancy before body mass significantly increased, they were subtle and only measurable in exacerbated conditions. This challenges the assumed necessity of balance enhancing interventions in pregnant women. Although the MSB significantly affected body posture, the magnitude of the LoS improvement using the MSB was very small. Thus, it remains debatable if the MSB is a meaningful tool to increase balance during pregnancy.

Dynamic Compression Promotes the Matrix Synthesis of Nucleus Pulposus Cells Through Up-Regulating N-CDH Expression in a Perfusion Bioreactor Culture

BACKGROUND/AIMS

An adequate matrix production of nucleus pulposus (NP) cells is an important tissue engineering-based strategy to regenerate degenerative discs. Here, we mainly aimed to investigate the effects and mechanism of mechanical compression (i.e., static compression vs. dynamic compression) on the matrix synthesis of three-dimensional (3D) cultured NP cells in vitro.

METHODS

Rat NP cells seeded on small intestinal submucosa (SIS) cryogel scaffolds were cultured in the chambers of a self-developed, mechanically active bioreactor for 10 days. Meanwhile, the NP cells were subjected to compression (static compression or dynamic compression at a 10% scaffold deformation) for 6 hours once per day. Unloaded NP cells were used as controls. The cellular phenotype and matrix biosynthesis of NP cells were investigated by real-time PCR and Western blotting assays. Lentivirus-mediated N-cadherin (N-CDH) knockdown and an inhibitor, LY294002, were used to further investigate the role of N-CDH and the PI3K/Akt pathway in this process.

RESULTS

Dynamic compression better maintained the expression of cell-specific markers (keratin-19, FOXF1 and PAX1) and matrix macromolecules (aggrecan and collagen II), as well as N-CDH expression and the activity of the PI3K/Akt pathway, in the 3D-cultured NP cells compared with those expression levels and activity in the cells grown under static compression. Further analysis showed that the N-CDH knockdown significantly down-regulated the expression of NP cell-specific markers and matrix macromolecules and inhibited the activation of the PI3K/Akt pathway under dynamic compression. However, inhibition of the PI3K/Akt pathway had no effects on N-CDH expression but down-regulated the expression of NP cell-specific markers and matrix macromolecules under dynamic compression.

CONCLUSION

Dynamic compression increases the matrix synthesis of 3D-cultured NP cells compared with that of the cells under static compression, and the N-CDH-PI3K/Akt pathway is involved in this regulatory process. This study provides a promising strategy to promote the matrix deposition of tissue-engineered NP tissue in vitro prior to clinical transplantation.

A first step towards a consensus static in vitro model for simulating full-term infant digestion

In vitro alternatives to clinical trials are used for studying human food digestion. For simulating infant digestion, only a few models, lacking physiological relevance, are available. Thanks to an extensive literature review of the in vivo infant digestive conditions, a gastrointestinal static in vitro model was developed for infants born at term and aged 28days. The model was applied to the digestion of a commercial infant formula. Kinetics of digestion, as well as the structural evolution, were compared with those obtained while submitting the same formula to the adult international consensus protocol of in vitro static digestion. The kinetics of proteolysis and lipolysis differed according to the physiological stage resulting mainly from the reduced level of enzymes and bile salts, as well as the higher gastric pH in the infant model. This in vitro static model of infant digestion is of interest for scientists, food or pharmaceutical manufacturers.

Challenging the foundations of the clinical model of foot function: further evidence that the root model assessments fail to appropriately classify foot function

BACKGROUND

The Root model of normal and abnormal foot function remains the basis for clinical foot orthotic practice globally. Our aim was to investigate the relationship between foot deformities and kinematic compensations that are the foundations of the model.

METHODS

A convenience sample of 140 were screened and 100 symptom free participants aged 18-45 years were invited to participate. The static biomechanical assessment described by the Root model was used to identify five foot deformities. A 6 segment foot model was used to measure foot kinematics during gait. Statistical tests compared foot kinematics between feet with and without foot deformities and correlated the degree of deformity with any compensatory motions.

RESULTS

None of the deformities proposed by the Root model were associated with distinct differences in foot kinematics during gait when compared to those without deformities or each other. Static and dynamic parameters were not correlated.

CONCLUSIONS

Taken as part of a wider body of evidence, the results of this study have profound implications for clinical foot health practice. We believe that the assessment protocol advocated by the Root model is no longer a suitable basis for professional practice. We recommend that clinicians stop using sub-talar neutral position during clinical assessments and stop assessing the non-weight bearing range of ankle dorsiflexion, first ray position and forefoot alignments and movement as a means of defining the associated foot deformities. The results question the relevance of the Root assessments in the prescription of foot orthoses.

Intra and intersession repeatability and reliability of the S-Plate® pressure platform

AIM

The aim of this study was to assess the repeatability and reliability of the S-Plate® pressure platform in a group of healthy subjects.

MATERIAL AND METHODS

Forty subjects, free from physical conditions that would affect normal gait, walked along a five-meter corridor while data were recorded from the pressure platform. A total of 10 steps (five each side) were obtained as well as five static trials; the same measurements were repeated one week later. Peak and mean plantar pressures and contact area were recorded for both dynamic and static trials. Additionally, weight supported on each limb was documented during static trials. To assess intrasession and intersession repeatability and reliability, the intraclass correlation coefficients (ICCs) and coefficient of variation (CoV) were calculated.

RESULTS

Taking the ICC values into account, every static and dynamic variable analysed showed moderate to excellent reliability and the CoV values were all below 12%.

CONCLUSION

Measurements of either static or dynamic plantar pressure variables with the S-Plate® pressure platform show good repeatability and reliability, and so it is useful for comparing steps within and between sessions.

Matching novel face and voice identity using static and dynamic facial images

Research investigating whether faces and voices share common source identity information has offered contradictory results. Accurate face-voice matching is consistently above chance when the facial stimuli are dynamic, but not when the facial stimuli are static. We tested whether procedural differences might help to account for the previous inconsistencies. In Experiment 1, participants completed a sequential two-alternative forced choice matching task. They either heard a voice and then saw two faces or saw a face and then heard two voices. Face-voice matching was above chance when the facial stimuli were dynamic and articulating, but not when they were static. In Experiment 2, we tested whether matching was more accurate when faces and voices were presented simultaneously. The participants saw two face-voice combinations, presented one after the other. They had to decide which combination was the same identity. As in Experiment 1, only dynamic face-voice matching was above chance. In Experiment 3, participants heard a voice and then saw two static faces presented simultaneously. With this procedure, static face-voice matching was above chance. The overall results, analyzed using multilevel modeling, showed that voices and dynamic articulating faces, as well as voices and static faces, share concordant source identity information. It seems, therefore, that above-chance static face-voice matching is sensitive to the experimental procedure employed. In addition, the inconsistencies in previous research might depend on the specific stimulus sets used; our multilevel modeling analyses show that some people look and sound more similar than others.

3D strength surfaces for ankle plantar- and dorsi-flexion in healthy adults: an isometric and isokinetic dynamometry study

BACKGROUND

The ankle is an important component of the human kinetic chain, and deficits in ankle strength can negatively impact functional tasks such as balance and gait. While peak torque is influenced by joint angle and movement velocity, ankle strength is typically reported for a single angle or movement speed. To better identify deficits and track recovery of ankle strength after injury or surgical intervention, ankle strength across a range of movement velocities and joint angles in healthy adults is needed. Thus, the primary goals of this study were to generate a database of strength values and 3-dimensional strength surface models for plantarflexion (PF) and dorsiflexion (DF) ankle strength in healthy men and women. Secondary goals were to develop a means to estimate ankle strength percentiles as well as examine predictors of maximal ankle strength in healthy adults.

METHODS

Using an isokinetic dynamometer, we tested PF and DF peak torques at five joint angles (-10° [DF], 0° [neutral], 10° [PF], 20° [PF] and 30° [PF]) and six velocities (0°/s, 30°/s, 60°/s, 90°/s, 120°/s and 180°/s) in 53 healthy adults. These data were used to generate 3D plots, or "strength surfaces", for males and females for each direction; surfaces were fit using a logistic equation. We also tested predictors of ankle strength, including height, weight, sex, and self-reported physical activity levels.

RESULTS

Torque-velocity and torque-angle relationships at the ankle interact, indicating that these relationships are interdependent and best modeled using 3D surfaces. Sex was the strongest predictor of ankle strength over height, weight, and self-reported physical activity levels. 79 to 97 % of the variance in mean peak torque was explained by joint angle and movement velocity using logistic equations, for men and women and PF and DF directions separately.

CONCLUSIONS

The 3D strength data and surface models provide a more comprehensive dataset of ankle strength in healthy adults than previously reported. These models may allow researchers and clinicians to quantify ankle strength deficits and track recovery in patient populations, using angle- and velocity-specific ankle strength values and/or strength percentiles from healthy adults.

Standing on a declining surface reduces transient prolonged standing induced low back pain development

While alternating standing position on a sloped surface has proven successful at reducing low back pain during standing, the purpose of this study was to evaluate standing solely on a declining surface to isolate the influence of the postural change. Seventeen participants performed two 75-min prolonged standing occupational simulations- level ground and declining surface. Fifty-three percent of participants (9/17) were categorized as pain developers during the level ground standing condition. For these same pain developers, their average maximum pain scores were 58% lower during sloped standing. All participants showed greater hip flexion, trunk-to-thigh angle flexion, and posterior translation of the trunk center of gravity when standing on the sloped surface. These postural changes could cause the muscles crossing the hip posteriorly to increase passive stiffness and assist with stabilizing the pelvis. This study stresses the importance of hip kinematics, not just lumbar spine posture, in reducing prolonged standing induced low back pain.

Effect of Cardiac-Cycle-Synchronized Selective Vagal Stimulation on Heart Rate and Blood Pressure in Rats

INTRODUCTION

Activation of the baroreflex system through the selective vagal nerve stimulation (sVNS) may become a treatment option for therapy-resistant hypertension, which is a frequently observed problem in the antihypertensive therapy. In previous studies, we used continuous sVNS to lower blood pressure (BP) without major side effects in a rat model. As continuous stimulation is energy consuming and sVNS could be implemented in an antihypertensive stimulator, it was the aim of this study to investigate the efficacy of pulsatile, cardiac-cycle-synchronized sVNS (cssVNS) on the reduction of BP.

METHODS

A multichannel cuff electrode was wrapped around the left vagal nerve in six male Wistar rats under Isoflurane anesthesia. BP was recorded in the left carotid artery. An electrocardiogram (ECG) was obtained via subcutaneous needle electrodes. The aortic depressor nerve fibers in the vagal nerve bundle were selectively stimulated with 18 parameter settings within a window of 15-30 ms after the R-peak in the ECG. The stimulation paradigm included every heartbeat, every second heart beat, and every third heart beat. BP and heart rate were initially recorded over 10 min.

RESULTS

Using cssVNS, BP could be significantly reduced over 30 min and maintained at this level. While the highest BP reduction was seen during cssVNS at every heartbeat with minimal bradycardia, less-yet significant-BP reduction was seen during cssVNS at every second or third heartbeat without causing detectable bradycardia.

CONCLUSION

cssVNS can chronically reduce BP in rats avoiding measurable bradycardic side effects. This energy-efficient technique might allow the implementation of sVNS using an implantable device to permanently lower BP in patients.

FUNDING

The study was funded by Bundesministerium fur Bildung und Forschung/German Federal Ministry of Education and Research among the call "Individualisierte Medizintechnik" under the grant number FKZ 13GW0120B.

Fatigue behavior of zirconia under different loading conditions

PURPOSE

To investigate the influence of surface damage on the fatigue behavior of zirconia under two different loading conditions.

MATERIALS AND METHODS

One hundred twenty zirconia bar-shaped received either airborne particle abrasion using 50μm or 120μm alumina particles while polished specimens served as control. The specimens were subjected to two fatigue regimes: dynamic fatigue (1,000,000 cycles, 1hz and 0.5s contact time) or static fatigue (a constant load applied for 5000s) under water using the staircase application of the load. The flexure strength after fatigue (dynamic fatigue strength) was compared to the initial flexure strength of the tested specimens (α=0.05). The critical crack shape and size of fractured specimens was examined using scanning electron microscopy.

RESULTS

Compared to the initial flexure strength of the tested specimens, dynamic fatigue strength was 86.3% for the polished specimens, 73.4% for 50μm particle abrasion, and 42.3% for 120μm particle abrasion while the static fatigue strength was 85.9%, 78.5%, and 51.5% respectively. Significant statistical differences (F=223.679, P<0.001) were found between different surface treatments but not between dynamic and static fatigue strengths for the same type of surface treatment.

CONCLUSIONS

The dynamic and static fatigue strengths of zirconia are significantly influenced by type of surface damage.

CLINICAL IMPLICATIONS

Within the limitations of this study, surface damage have great influence on fatigue behavior of zirconia.

Bumped kinase inhibitor prohibits egression in Babesia bovis

Babesiosis is a global zoonotic disease acquired by the bite of a Babesia-infected Ixodes tick or through blood transfusion with clinical relevance affecting humans and animals. In this study, we evaluated a series of small molecule compounds that have previously been shown to target specific apicomplexan enzymes in Plasmodium, Toxoplasma and Cryptosporidium. The compounds, bumped kinase inhibitors (BKIs), have strong therapeutic potential targeting apicomplexa-specific calcium dependent protein kinases (CDPKs). We investigated if BKIs also show inhibitory activities against piroplasms such as Babesia. Using a subset of BKIs that have promising inhibitory activities to Plasmodium and Toxoplasma, we determined that their actions ranged from 100% and no inhibition against Babesia bovis blood stages. One specific BKI, RM-1-152, showed complete inhibition against B. bovis within 48h and was the only BKI that showed noticeable phenotypic changes to the parasites. Focusing our study on this BKI, we further demonstrated that RM-1-152 has Babesia-static activity and involves the prohibition of merozoite egress while replication and re-invasion of host cells are unaffected. The distinct, abnormal phenotype induced by RM-1-152 suggests that this BKI can be used to investigate less studied cellular processes such as egression in piroplasm.

3D shoulder kinematics for static vs dynamic and passive vs active testing conditions

Shoulder motion analysis provides clinicians with references of normal joint rotations. Shoulder joints orientations assessment is often based on series of static positions, while clinicians perform either passive or active tests and exercises mostly in dynamic. These conditions of motion could modify joint coordination and lead to discrepancies with the established references. Hence, the objective was to evaluate the influence of static vs dynamic and passive vs active testing conditions on shoulder joints orientations. Twenty asymptomatic subjects setup with 45 markers on the upper limb and trunk were tracked by an optoelectronic system. Static positions (30°, 60°, 90° and 120° of thoracohumeral elevation) and dynamic motion both in active condition and passively mobilised by an examiner were executed. Three-dimensional sternoclavicular, acromioclavicular, scapulothoracic and glenohumeral joint angles (12 in total) representing the distal segment orientation relative to the proximal segment orientation were estimated using a shoulder kinematical chain model. Separate four-way repeated measures ANOVA were applied on the 12 joint angles with factors of static vs dynamic, passive vs active, thoracohumeral elevation angle (30°, 60°, 90° and 120°) and plane of elevation (frontal and sagittal). Scapulothoracic lateral rotation progressed more during arm elevation in static than in dynamic gaining 4.2° more, and also in passive than in active by 6.6°. Glenohumeral elevation increased more during arm elevation in active than in passive by 4.4°. Shoulder joints orientations are affected by the testing conditions, which should be taken into consideration for data acquisition, inter-study comparison or clinical applications.

Overview of Telepathology

Telepathology is the practice of remote pathology using telecommunication links to enable the electronic transmission of digital pathology images. Telepathology can be used for remotely rendering primary diagnoses, second opinion consultations, quality assurance, education, and research purposes. The use of telepathology for clinical patient care has been limited mostly to large academic institutions. Barriers that have limited its widespread use include prohibitive costs, legal and regulatory issues, technologic drawbacks, resistance from pathologists, and above all a lack of universal standards. This article provides an overview of telepathology technology and applications.

Imaging characteristics of "dynamic" versus "static" spondylolisthesis: analysis using magnetic resonance imaging and flexion/extension films

BACKGROUND CONTEXT

Traditionally, the "dynamic" and "static" types of spondylolisthesis have been lumped into a single group in the literature. The goal of this study was to define the radiographic characteristics of "dynamic" and "static" spondylolisthesis with the use of magnetic resonance imaging (MRI) and flexion/extension radiographs.

PURPOSE

Describe the characteristic findings present on MRI and flexion/extension radiographs that are associated with dynamic versus static spondylolisthesis.

STUDY DESIGN

Retrospective radiographic/imaging study.

METHODS

From 2009 to 2011, patients who underwent elective primary posterior spinal fusion for the diagnosis of spondylolisthesis had their plain films assessed for the degree of spondylolisthesis and were designated "dynamic" or "static," as defined by historical measures. Axial and sagittal T2 MRIs were evaluated for associated facet fluid (FF), facet cysts, interspinous fluid (ISF), and facet hypertrophy. These finding were then statistically evaluated for associations between dynamic and static spondylolisthesis on flexion/extension radiographs and characteristic MRI findings.

RESULTS

Ninety patients were included in the study with 114 levels examined for spondylolisthesis. Patients with greater than 3 mm of instability on flexion/extension films were more likely to have FF (p=.018) and ISF (p<.001). Of the patients who had a greater than 3 mm of instability, 39.5% did not demonstrate spondylolisthesis on the sagittal MRI reconstruction. If ISF was present on MRI, there was a positive predictive value of 69.0% that there would be greater than 3 mm instability on flexion/extension films. Absence of FF on MRI had a positive predictive value of 75.6% for instability less than 3 mm on flexion/extension films. In the presence of ISF on MRI, the likelihood ratio of finding more than 3 mm of instability on flexion/extension films was 3.68. The presence of FF on MRI had a likelihood ratio of 1.43 for instability. A total of 36.8% of all spondylolisthesis reduced when supine on MRI.

CONCLUSIONS

The presence of FF and/or ISF is associated with instability greater than 3 mm in flexion/extension radiographs.

The effect of leg length discrepancy upon load distribution in the static phase (standing)

Leg length discrepancy (LLD) is commonly recognised as a complication of total hip arthroplasty. Some patients with only minor LLD complain of major difficulties. The effect of LLD has been described in the dynamic phase, but not static phase. The aim of this project was to investigate the effect of leg length discrepancy on static limb loading (i.e. Standing). A pedobarograph was used to measure the limb loading of 20 normal volunteers whilst changing the height of the other foot thus simulating a LLD. With both feet at the same level, the left limb took 54% of the load. When the right foot was lower, (simulating a long left leg), the left leg took 39% of the load. When the right foot was higher, (simulating a long right leg), the left leg took 65% of the load. A paired t-test comparison of the simulation with the level load showed a significant difference with P=0.002. Our results show that weight distribution increased in the shorter limb when LLD was simulated. This uneven distribution is likely to lead to premature fatigue when standing and may explain why some patients with LLD post hip arthroplasty have poorer outcomes.

Increased range of motion after static stretching is not due to changes in muscle and tendon structures

BACKGROUND

It is known that static stretching is an appropriate means of increasing the range of motion, but information in the literature about the mechanical adaptation of the muscle-tendon unit is scarce. Therefore, the purpose of this study was to investigate the influence of a six-week static stretching training program on the structural and functional parameters of the human gastrocnemius medialis muscle and the Achilles tendon.

METHODS

A total of 49 volunteers were randomly assigned into static stretching and control groups. Before and following the stretching intervention, we determined the maximum dorsiflexion range of motion with the corresponding fascicle length and pennation angle. Passive resistive torque and maximum voluntary contraction were measured with a dynamometer. Muscle-tendon junction displacement allowed us to determine the length changes in tendon and muscle, and hence to calculate stiffness. Fascicle length, pennation angle, and muscle tendon junction displacement were measured with ultrasound.

FINDINGS

Mean range of motion increased significantly from 30.9 (5.3) to 36.3 (6.1) in the intervention group, but other functional (passive resistive torque, maximum voluntary contraction) and structural (fascicle length, pennation angle, muscle stiffness, tendon stiffness) parameters were unaltered.

INTERPRETATION

The increased range of motion could not be explained by the structural changes in the muscle-tendon unit, and was likely due to increased stretch tolerance possibly due to adaptations of nociceptive nerve endings.

Biomechanical analysis of different types of pedicle screw augmentation: a cadaveric and synthetic bone sample study of instrumented vertebral specimens

This study aims to determine the pull-out strength, stiffness and failure pull-out energy of cement-augmented, cannulated-fenestrated pedicle screws in an osteoporotic cadaveric thoracolumbar model, and to determine, using synthetic bone samples, the extraction torques of screws pre-filled with cement and those with cement injected through perforations. Radiographs and bone mineral density measurements from 32 fresh thoracolumbar vertebrae were used to define specimen quality. Axial pull-out strength of screws was determined through mechanical testing. Mechanical pull-out strength, stiffness and energy-to-failure ratio were recorded for cement-augmented and non-cement-augmented screws. Synthetic bone simulating a human spinal bone with severe osteoporosis was used to measure the maximum extraction torque. The pull-out strength and stiffness-to-failure ratio of cement pre-filled and cement-injected screws were significantly higher than the non-cement-augmented control group. However, the cement pre-filled and cement-injected groups did not differ significantly across these values (p=0.07). The cement pre-filled group had the highest failure pull-out energy, approximately 2.8 times greater than that of the cement-injected (p<0.001), and approximately 11.5 times greater than that of the control groups (p<0.001). In the axial pull-out test, the cement-injected group had a greater maximum extraction torque than the cement pre-filled group, but was statistically insignificant (p=0.17). The initial fixation strength of cannulated screws pre-filled with cement is similar to that of cannulated screws injected with cement through perforations. This comparable strength, along with the heightened pull-out energy and reduced extraction torque, indicates that pedicle screws pre-filled with cement are superior for bone fixation over pedicle screws injected with cement.

Static cardiomyoplasty with synthetic elastic net suppresses ventricular dilatation and dysfunction after myocardial infarction in the rat: a chronic study

Although static cardiomyoplasty prevents the left ventricle (LV) from dilatation, it may interfere with diastolic relaxation, or cause restriction. We developed a synthetic net with dual elasticity and tested its effect late after myocardial infarction in the rat. LV pressure-volume relationships (PVR) were successively analyzed before, after intravenous volume load, and 10 minutes after occlusion of the left anterior descending artery. Rats were then randomized into groups receiving synthetic net wrapping around the heart (NET+, n = 8) and only partially behind LV (NET-, n = 9), and they underwent the same PVR studies 6 weeks later. End-diastolic and end-systolic PVR were defined, and LV size and function were compared under standardized loading conditions. Although there was no difference in Day 0, increase in LV end-diastolic and end-systolic volumes were significantly attenuated in NET+ rats 6 weeks later when there was a significant correlation between LV volumes by PVR estimation and actual measurements, with significant differences in both measures between the groups: NET+ < NET-. The presence or absence of net did not show restrictive hemodynamics under acute volume load. Static cardiomyoplasty using a synthetic elastic net significantly attenuated LV dilatation and dysfunction without restriction late after myocardial infarction in the rat.

The relationship between parameters of static and dynamic stability tests

BACKGROUND

Stability is often described to be static (quiet standing) and dynamic (maintaining a stable position while undertake a prescribed movement). Many researchers have used only static tests to evaluate the stability of normal and handicapped subjects. However, it is important to evaluate the stability of subjects while undertaking various tasks (dynamic stability). It is not currently clear whether static balance can predict dynamic balance or not. Therefore, the aim of this research was to investigate the relationship between parameters of static and dynamic stability tests.

METHODS

The current clinical trial study was carried out in the Bioengineering Unit of Strathclyde University during 2008 and 2009. The normal subjects with no history of musculoskeletal disorders from staff and students of the Unit were selected in this study. Twenty-five normal subjects were recruited to participate in this research project. They were asked to stand on a force plate in quiet standing and while undertaking various hand tasks. The functional stability of the subjects was measured while transverse and vertical reaching tasks were undertaken. The correlation between various parameters of stability in quiet standing and functional hand tasks was evaluated using Pearson correlation.

RESULTS

There was no significant correlation between static and dynamic stability parameters. The Pearson correlation coefficients for all parameters regarding the static and dynamic tests were less than 0.46.

CONCLUSIONS

As there was no correlation between stability parameters in quiet standing and while performing various hand tasks, it is not practical to discuss ability of the subjects to control their balance while undertaking various hand tasks based on static balance ability.