Muscular Stiffness Research Articles

Shear wave elastography investigation of multifidus stiffness in individuals with low back pain

The purpose of this study was to investigate differences in passive muscular stiffness between the superficial multifidus (SM) and deep multifidus (DM), and to compare their passive and active stiffness in individuals with low back pain (LBP) and asymptomatic individuals. Fifteen LBP individuals and 15 asymptomatic individuals were recruited. Passive stiffness of the SM and DM was measured bilaterally using shear wave elastography (SWE) with participants lying prone. Active stiffness was measured for the SM during trunk extension, and the contraction ratio was calculated. DM displayed higher passive muscular stiffness than SM in both the asymptomatic and LBP groups (14.41 ± 2.62 and 15.40 ± 2.77 kPa respectively; p < 0.001). Individuals with LBP exhibited higher passive muscular stiffness of SM (LBP: 10.15 ± 4.21, asymptomatic: 6.84 ± 1.69 kPa; p < 0.005) and a lower contraction ratio (LBP: 1.54 ± 0.47, asymptomatic: 2.65 ± 1.36 kPa; p < 0.003) compared to the asymptomatic group. The findings support a differentiation in passive muscular stiffness between SM and DM and provide evidence for an alteration in muscular stiffness at rest in individuals with LBP. The lower increase of muscular stiffness with contraction observed for those with LBP may reflect a deficit in activation of the multifidus.

Foam Rolling of the Calf and Anterior Thigh: Biomechanical Loads and Acute Effects on Vertical Jump Height and Muscle Stiffness.

When considering the scientific lack concerning the execution and acute effects and mechanism of foam rolling (FR), this study has evaluated the biomechanical loads by the force-time characteristics during two popular FR exercises. Additionally, the acute effects of FR on jump height and muscular stiffness were simultaneously assessed. Within a randomized cross-over design, 20 males (26.6 ± 2.7 years; 181.6 ± 6.8 cm; 80.4 ± 9.1 kg) were tested on different days pre, post, and 15 and 30 min after three interventions. The interventions consisted of a FR procedure for the calf and anterior thigh of both legs, 10 min ergometer cycling, and resting as a control. Stiffness was measured via mechanomyography at the thigh, calf, and ankle. The vertical ground reaction forces were measured under the roller device during FR as well as to estimate jump height. Within the FR exercises, the forces decreased from the proximal to distal position, and were in mean 34 and 32% of body weight for the calves and thighs, respectively. Importantly, with 51 to 55%, the maxima of the individual mean forces were considerably higher. Jump height did not change after FR, but increased after cycling. Moreover, stiffness of the thigh decreased after FR and increased after cycling.

Influence of a Modified Step Frequency on Energy Cost of Running after a Downhill Run in Non-Expert Subjects

Purpose: The purpose of this study was to examine the role of step frequency (SF) on energy cost of running (Cr) after a downhill run (DHR) of 7.5 km (-6.7% grade) run at about 80% of heart rate reserve. Method: Pre- and post-DHR, force, stiffness and Cr at 70% of velocity at 2 V O • max were measured in twelve participants unaccustomed to mountain running. Post-DHR data were recorded at a freely chosen SF and at the pre-DHR SF. Results: A DHR induced reductions in the knee extensors force (-15.7%, P<0.001) and leg stiffness (-3.2%, P<0.05), an increase in blood lactate concentration, a significant increase in creatine kinase activity and muscle soreness. The post-DHR freely chosen SF increased (p<0.001) whereas Cr remained unchanged. Running at the pre-DHR SF induced an increase in the energy cost of running (+6.4%, p<0.05). A positive correlation (r=0.62, p<0.05) was observed between SF variations (pre to post at freely chosen SF) and Cr variations between the two post conditions. Conclusion: DHR-induced fatigue resulted in the selection of a new preferred SF limiting the rise in energy cost. SF seems to be unconsciously but efficiently adapted to the altered muscular force and stiffness after DHR.

Uticaj mehaničkih karakteristika mišića na ispoljavanje sile mišića opružača i pregibača zgloba kolena

The aim of the study is to investigate the influence of the muscle mechanical characteristics measured by the method of tensiomyography on the manifestation of the muscle force measured by the isokinetic dynamometry method in the knee joint extensor and flexor muscles. The sample consisted of 32 individuals (17 men and 15 women) who were students of the Faculty of sports and physical education and the Criminalist-police academy. Measurements of maximal displacement were performed on the muscles rectus femoris, vastus lateralis, vastus medialis, biceps femoris and semitendinosus of right and left leg. Maximal peak torque was measured on the knee joint extensor and flexor muscles of the right and left leg in concentric mode at a speed of 60 ˚/s. Multiple linear regression analysis was applied to determine the influence of the system of predictor variables on muscle force. The results of the study showed that there was no significant influence of the maximal displacement parameters on the peak torque parameters (Adj. R2 = 0.103, p = 0.462, on average). It can be concluded that the muscular stiffness of the knee joint extensor and flexor muscles has no significant influence on the muscle force manifestation of the respective muscle groups and that the tensiomyography parameter maximal displacement has low predictive values, that is, it cannot be used in muscle force evaluation.

Longitudinal gait assessment in a stiff person syndrome.

Stiff person syndrome (SPS) is an autoimmune disorder with multiple clinical presentations, all characterized by generalized or focal muscular stiffness leading to abnormal postures and movements. To date, no standardized treatments are available; also, the outcome measures are mainly clinical based and unstandardized, limiting the reliability of clinical trials. In this case study, we used the eight-camera motion capture system for gait analysis (GA) to outline the gait features and track the clinical evolution of a young patient with SPS receiving a personalized multimodal therapy. GA was accurate in reflecting clinical changes over a 7-week-long period, thus representing a potential source for objective biomarkers in SPS. Therefore, future studies focusing on either the natural history or the treatment of SPS could adopt GA for reliable outocome measures, confirming this preliminary observation.

Interrater reliability of ultrasound elastography to examine the stiffness and elasticity of muscles and fascia of the lower extremity in healthy adults

Introduction: Ultrasound elastography is one of the first real-time imaging techniques to quantify mechanical tissue properties. With the help of ultrasound elastography, therapists' palpation techniques can be further developed diagnostically, and different muscular and fascial tissue stiffness can be shown objectively and visually (Brandenburg et al 2014).

Effect of Eclipta alba and Ocimum sanctum on haloperidol induced parkinsonism

The aim of the study is protective effect of compound Eclipta alba and Ocimum sanctum on Parkinsonism induced mice by haloperidol injection. Parkinsonism is neurodegenerative disease due to the deficiency of dopamine in brain. The pathological hallmark of Parkinson’s disease in the cell loss within substantia nigra pars compacta (SNpc) region and the disease is charactrised by bradykinesia, rigidity, postural instability, orofacial dyskinesia, muscular stiffness and tremor1. Mice were injected 1mg/kg haloperidol and then treated with test and standard substance for 15 days. The impairment in catatonia in mice were tested using catatonic activity. Biochemical analysis of brain homogenate was performed so ass to assess brain Thiobarbituric acid reactive substance (TBARS) level and reduced glutathione (GSH) and TNF-α level were measured to assess total oxidative stress. EA 300mg/kg and OS 400mg/kg show slightly change in catatonic activity in mice while EA 600mg/kg and 800mg/kg significantly change in catatonic activity. Furthermore, Eclipta alba and Ocimum sanctum prevent the haloperidol induced changes in the level of brain TBARS, GSH and TNF-α. From the results we conclude that Eclipta alba and Ocimum sanctum has protective action against impairment in catatonic activity and pathological damage due to oxidative stress induced by intraperitoneally injection of haloperidol in mice. &#x0D; Keywords: Eclipta alba, Ocimum Sanctum, Parkinsonism, Anti-oxidant.

Arthroscopic Repair of Acetabular Cartilage Lesions by Chitosan-Based Scaffold: Clinical Evaluation at Minimum 2 Years Follow-up

To evaluate the functional outcome of using chitosan-based material in our patients after 2years of follow-up. Nonarthritic nondysplastic femoroacetabular impingement patients with an acetabular chondral lesion, 18 to 55years of age, were included for arthroscopic repair between May 2013 and July 2015. Full-thickness chondral defects ≥2cm2 were filled with chitosan-based implant after microfractures. Follow-up consisted of alpha angle assessment and clinical outcome in the form of the Non Arthritic Hip Score (NAHS), International Hip Outcome Tool 33 (iHOT33), Hip Outcome Score of Activities of Daily Living (HOS-ADL), and Hip Outcome Score of Sports Specific Scale (HOS-SSS). Twenty-three patients were included. The mean follow-up was 38.4 ± 7.0months (range, 24-50months). The mean defect size was 3.5 ± 1.0cm2, principally involving zone 2 and to a lesser extent in zones 1 and 3. Using femoroplasty, the alpha angle was corrected from a mean 70.5 ± 6.3° to 44.3 ± 4.9° (P= .00001). Significant improvement occurred comparing the preoperative to the first-year postoperative patient-reported outcomes: P= .00001 for the NAHS, P= .00004 for the iHOT33, P= .00005 for the HOS-ADL, and P= .0002 for the HOS-SSS. No statistically significant change has been observed in the patient-reported outcomes obtained at the endpoint when compared with the first-year values (P= .13 for the NAHS, P= .21 for the HOS-ADL, and P= .29 for the HOS-SSS), except for the iHOT33, which showed further significant improvement (P= .02). Up to 91% of the patients met or exceeded the minimal clinically important difference. One patient needed total hip arthroplasty. Perineal hypoesthesia occurred in 3 patients, who recovered within 2 to 6weeks, and 1 patient needed a prolonged physiotherapy program for postoperative muscular stiffness. The arthroscopic combined treatment of microfractures and chitosan-based scaffold has maintained satisfactory clinical outcomes in 91% of the patients with s large (≥2cm2) full-thickness acetabular chondral defect associated with femoroacetabular impingement at a mean follow-up of 38.4months. The study could not definitely draw any conclusion regarding the safety of chitosan-based material for use in the hip joint. Level IV, case series.

Effect of sensory-motor latencies and active muscular stiffness on stability for an ankle-hip model of balance on a balance board

To achieve human upright posture (UP) and avoid falls, the central nervous system processes visual, vestibular, and proprioceptive information to activate the appropriate muscles to accelerate or decelerate the body’s center of mass. In this process, sensory-motor (SM) latencies and muscular deficits, even in healthy older adults, may cause falls. This condition is worse for people with chronic neuromuscular deficits (stroke survivors, patients with multiple sclerosis or Parkinson’s disease). One therapeutic approach is to recover or improve quiet UP by utilizing a balance board (BB) (a rotating surface with a tunable stiffness and time delay), where a patient attempts to maintain UP while task difficulty is manipulated. While BBs are commonly used, it is unclear how UP is maintained or how changes in system parameters such as SM latencies and BB time delay affect UP stability. To understand these questions, it is important that mathematical models be developed with enough degrees-of-freedom to capture the many responses evoked during the maintenance of UP on a BB. This paper presents an ankle-hip model of balance on a BB, which is used to study the combined effect of SM latencies and active muscular stiffness of the ankle and hip joints, and the BB stiffness and time delay on UP stability. The analysis predicts that people with proprioceptive, visual, vestibular loss, or increased SM latencies may show either leaning postures or larger body-sway. The results show that the BB time delay and the visual and vestibular feedback have the largest impact on UP stability.

Acute Effect of Basketball-Specific Exercise on Lower Limb Injury Risk Mechanisms in Male Basketball Players U16 and U18

The aim of this study was to examine and compare the acute effects of basketball-specific fatigue on muscular stiffness and reactive strength in male adolescent basketball players of two age categories. Reactive strength, expressed by means of the reactive strength index (RSI), and leg stiffness (LS) as mechanisms associated with the risk of ACL injury were measured in eleven players of the U16 category (age 16.1 ± 0.4 years; body height 185 ± 6.5 cm; body mass 74.3 ± 9.9 kg) and ten players of the U18 category (age 17.7 ± 0.4 years; body height 187 ± 5.7 cm; body mass 79.7 ± 7.4 kg) pre and post simulated basketball match play (SBFP28). RSI was determined by a drop jump test, LS by a 20 sub-maximal two-legged hopping test. No significant effects of SBFP28 on the monitored parameters were observed with the exception of RSI in U16 (p = 0.013, r = 0.53). Similarly, there were no significant differences in the fatigue-related responses to SBFP28 for RSI and LS between the age groups. These results indicated that irrespective of age, the stabilization function of the knee muscles was not impaired and consequently the risk of ACL injury was not increased.

Sex-Based Differences of Medial Collateral Ligament and Anterior Cruciate Ligament Strains With Cadaveric Impact Simulations.

Background:Female patients sustain noncontact knee ligament injuries at a greater rate compared with their male counterparts. The cause of these differences in the injury rate and the movements that load the ligaments until failure are still under dispute in the literature.Purpose/Hypotheses:This study was designed to determine differences in anterior cruciate ligament (ACL) and medial collateral ligament (MCL) strains between male and female cadaveric specimens during a simulated athletic task. The primary hypothesis tested was that female limbs would demonstrate significantly greater ACL strain compared with male limbs under similar loading conditions. A secondary hypothesis was that MCL strain would not differ between sexes.Study Design:Controlled laboratory study.Methods:Motion analysis of 67 athletes performing a drop vertical jump was conducted. Kinetic data were used to categorize injury risk according to tertiles, and these values were input into a cadaveric impact simulator to assess ligamentous strain during a simulated landing task. Uniaxial and multiaxial load cells and differential variable reluctance transducer strain sensors were utilized to collect mechanical data for analysis. Conditions of external loads applied to the cadaveric limbs (knee abduction moment, anterior tibial shear, and internal tibial rotation) were varied and randomized. Data were analyzed using 1-way analysis of variance (ANOVA), 2-way repeated-measures ANOVA, and the Fisher exact test.Results:There were no significant differences (P = .184) in maximum ACL strain between male (13.2% ± 8.1%) and female (16.7% ± 8.3%) specimens. Two-way ANOVA demonstrated that across all controlled external load conditions, female specimens consistently attained at least 3.5% increased maximum ACL strain compared with male specimens (F 1,100 = 4.188, P = .043); however, when normalized to initial contact, no significant difference was found. There were no significant differences in MCL strain between sexes for similar parameters.Conclusion:When compared with baseline, female specimens exhibited greater values of ACL strain at maximum, initial contact, and after impact (33, 66, and 100 milliseconds, respectively) than male specimens during similar loading conditions, with a maximum strain difference of at least 3.5%. During these same loading conditions, there were no differences in MCL loading between sexes, and only a minimal increase of MCL loading occurred during the impact forces. Our results indicate that female patients are at an increased risk for ACL strain across all similar conditions compared with male patients.Clinical Relevance:These data demonstrate that female specimens, when loaded similarly to male specimens, experience additional strain on the ACL. As the mechanical environment was similar for both sexes with these simulations, the greater ACL strain of female specimens must be attributed to ligament biology, anatomic differences, or muscular stiffness.

Respiratory failure in tetanic patient: maintenance of airway problem in intensive care unit setting

Tetanus is a toxin-mediated disease caused by Clostridium tetani resulting in muscular stiffness and painful spasm. The case fatality rates are high (10-80%), and the most frequent cause of mortality is airway problem that results in respiratory failure. A 52-year-old malecame to the hospital with lockjaw, rhesussardonicus, opisthotonus, and seizure for the last 12 hours, diagnosed with tetanus grade II. We placed the patient in an isolation room, gave 3000U tetanus immunoglobulin, 20mg diazepam in 500ml dextrose 5%/8 hours, and 500mg/6hrs metronidazole. On the seventh day, seizure became frequent, respiratory rate increased with crackles found on the auscultation, and the blood gas analysis showed respiratory failure type II (PCO2 53mmHg). The patientwas immediately sent to the ICU, intubated and given ventilator support. The patientwas sedated with continuous injection of midazolam 3 mg/h, morphine 10mcg/kgBW/h and also levofloxacin 750mg/24hours. Bronchoalveolar lavage culture was positive for Acinetobacter baumanii, so we changed the antibiotic to amikacin injection 500 mg/8hrs. After four days, we extubated the ventilator and transferred from HCU three days later. The patient was fully recovered and discharged after eighteen days of hospitalization.

Report Case of Van Der Knaap Syndrome in Two Ecuadorian Siblings

Van Der knaap syndrome is a very uncommon disease seen mainly in the Aggarwal community in northern India. The characteristics of this disease are early onset macrocephaly with mild motor developmental delay, progressive gait alterations, muscular stiffness (spasticity), progressive ataxia, sporadic seizures and usually mild cognitive impairment (MCI) which is of late appearance. Only a few cases of this pathology have been reported in worldwide literature. for the knowledge of all, there are no reports so far of two siblings of parents in which there is apparently no Indian descent or consanguinity. In this case the brothers started with abnormal growth of the cephalic perimeter, difficulty to start the march which progressively got worse, muscular stiffness was developed while intellectual functioning was preserved for several years after onset of the disorder. Was more notorious in one of the two brothers in terms of motor and speech deficit.

Passive stiffness in the supraspinatus muscle after double-row and knotless transossous equivalent repair: A cadaveric study

Background Although various techniques for arthroscopic rotator cuff repair have been introduced, optimal technique is still controversial. Biomechanical studies have been performed to assess tendon-bone interface properties. However, few studies have focused on the effect of the rotator cuff muscle after repair. To determine a technique with improved cuff function, in addition to repair strength, other factors such as stiffness changes in the rotator cuff muscle should also be analyzed. The purpose of this study was to investigate passive stiffness in the supraspinatus (SSP) muscle using shear wave elastography (SWE) after double-row (DR) and knotless transosseous equivalent (KL-TOE) techniques. Methods Twelve fresh-frozen cadaveric shoulders with rotator cuff tear (tear size; small [6], medium-large [6]) were used. Passive stiffness of 4 anatomical regions in the SSP muscle was measured based on an established SWE method. Each specimen underwent 2 types of footprint repair (DR and KL-TOE, in a random order) with the arm at 30° abduction. SWE values, obtained with the arm at 0°, 30°, and 90° abduction, were compared in 3 different conditions: preoperative (torn) and postoperative conditions with the 2 techniques. Results In shoulders with medium-large size tears, SSP muscles showed increased stiffness values after rotator cuff repair with both techniques, and this was significantly observed at 0° abduction. In addition, stiffness of the SSP muscle was uniform among 4 regions after KL-TOE repair, whereas, DR repair caused significantly heterogeneous stiffness distribution within the muscle (P > 0.01). SSP muscles with small size tear did not show any significant differences in stiffness values between regions and repair technique. Conclusion KL-TOE technique for the medium-large size tear provided a more uniform stiffness distribution in repaired SSP muscles compared to the DR technique. Imbalanced muscular stiffness might cause limited functional recovery after the cuff repair. In addition to established evidences of biomechanical properties, the alteration of cuff muscle stiffness should be evaluated to determine the optimal technique.

Quantitative assessment of muscular stiffness in children with cerebral palsy using acoustic radiation force impulse (ARFI) ultrasound elastography.

To evaluate the feasibility of quantitative analysis of muscle stiffness in the medial gastrocnemius muscle (GCM) by acoustic radiation force impulse (ARFI) ultrasound elastography in children with spastic cerebral palsy (CP). Seventeen children with spastic CP and 25 healthy children participated in the study between the years 2016-2017. The medial GCM in the CP group was assessed using the Modified Ashworth Scale (MAS) by a physiatrist. ARFI was used to measure the shear-wave velocities (SWVs) of the medial GCM. The mean SWV value for each MAS score was calculated and used for statistics. The mean SWV values of the medial GCM in the CP and healthy groups were 3.17±0.81m/s (mean±SD) and 1.45±0.25m/s (mean±SD), respectively. The SWV of the medial GCM significantly increased in the CP patients when compared with controls (p<0.001). In addition, the SWV values were correlated with the MAS scores (p<0.001). The interobserver agreement expressed as the interclass correlation coefficient was 0.65 (95% CI 0.33-0.84, p<0.001). ARFI imaging demonstrated a difference in muscle stiffness in the medial GCM between the CP and healthy groups. This method is a feasible imaging modality for the noninvasive assessment of contracting muscles in children with CP.

Gait variability and motor control in patients with knee osteoarthritis as measured by the uncontrolled manifold technique

Knee osteoarthritis (OA) causes pain, reduced muscular strength and stiffness of the affected joint. In response, the motor control mechanism is altered, potentially compromising stability during acts of daily living. Reduced walking stability can be quantified in terms of gait variability. This study therefore aimed to identify and quantify the effects of knee arthritis on gait variability. Fifty adults (25 males/25 females) with end-stage OA of the knee sufficiently symptomatic to require joint replacement, walked on a self-paced treadmill for 2min. A motion capture system was used to record 50 consecutive gait cycles from each patient. Kinematic variability of gait was analysed using the uncontrolled manifold technique (UCM). The position of the centre of mass (COM) was chosen as the task variable for the analysis. Results showed that our patient cohort were able to maintain a stable COM whilst walking, through adopting variable combinations of hip, knee and ankle kinematics. The greatest magnitudes of instability (based on the UCM ratios) occurred during initial contact and terminal stance. Active extension of the knee joint to approximately 5° is required during these gait cycle events, meaning that these gait events are highly quadriceps dependent. This study identified and quantified components of the gait cycle where patients with knee OA are most unstable. Employment of this technique could therefore allow specific personalised prescription for prehabilitation and rehabilitation.

The effect of topical thiocolchicoside in preventing and reducing the increase of muscle tone, stiffness, and soreness: A real-life study on top-level road cyclists during stage competition.

In professional road cyclists, the majority of overuse injuries affect the lower limbs and are mostly represented by contractures or muscle shortening, characterized by an increase of tone and stiffness and a variation of elasticity. Treatment and prevention of these specific conditions may include physical, supplementary, and pharmacologic support. The aim of this real-life study was to determine: first, the alterations of tone, stiffness, elasticity, and soreness of rectus femoris (RF) and biceps femoris (BF) in top class cyclists engaged in 3 multistage races, and second, whether any variable in the management of the athletes may affect the prevention and/or reduction of such alterations.Twenty-three professional cyclists competing in 3 international, cycling stage races were assessed. Athletes could receive, upon the approval of the medical staff, physical, dietary, and/or pharmacological management which could include treatments with topical over-the-counter myorelaxants to prevent and/or reduce muscle contractures. MyotonPro was used to daily measure tone, stiffness, and elasticity in RF and BF in relaxed and contracted state after every stage. In parallel, BF and RF soreness was also assessed with a Likert scale.All athletes received the same general massage management; none of them received dietary supplements; some of the athletes were treated with a topical myorelaxant thiocolchicoside (TCC 0.25%) foam 3 times daily. TCC was identified as the only variable able to affect these muscle parameters in the cyclists. Tone, stiffness (regardless of the state), and soreness significantly increased over time either in BF or RF in all athletes. In the group of athletes that used TCC (n = 11; TCC+) the increase in tone, stiffness, and soreness was significantly lower than in the group not receiving TCC (n = 12; No-TCC). Elasticity varied coherently with tone and stiffness.A very intense and protracted sport activity increases muscular tone, stiffness, and soreness over time. Topical TCC foam significantly attenuates these alterations and might represent an efficient strategy both to prevent and manage contractures and their consequences in professional cyclists as well in athletes from other disciplines involving similar workloads.

Mismatch between stiffness in elastic and muscular arteries as a predictor of vascular calcification in dialysis patients

Vascular calcification is one of the risk factors for arterial stiffness in patients with chronic kidney disease. We hypothesized that a mismatch between elastic and muscular arteries, represented as pulse wave velocity (PWV) ratio, could depict the extent of vascular calcification in end-stage renal disease. We also aimed to compare the predictive PWV ratio value to other factors possibly related to vascular calcification in dialysis population. In this cross-sectional study, in 60 chronic dialysis patients without previous cerebrovascular events, cardiovascular disease and events or clinically evident peripheral artery disease (ankle-brachial index >0.9), carotid-femoral and carotid-radial PWV as well as central hemodynamic parameters were measured by applanation tonometry (SphygmoCor). The PWV ratio using carotid-femoral PWV divided by carotid-radial PWV was calculated. Each patient underwent blood tests and chest X-ray for aortic arch calcification scoring. Two experienced radiologists blinded to patient's medical data evaluated chest X-rays (Cohen's kappa coefficient 0.76) and calculated how many sectors were calcified (Ogawa et al. in Hemodial Int 13:301-306, 2009). Differently scored chest X-rays were repeatedly reviewed and a consensus was reached. The study population consisted of 31 (51.7%) males and 29 (48.3%) females, mean age 52.73 ± 13.76years. Increased risk for aortic arch calcification was associated with higher PWV ratio even after adjustment for age, height, heart rate, ferritin level and C-reactive protein level (OR 2.59E+04, 95% CI 2.43E+01, 2.65E+09, p = 0.021). PWV ratio together with above-mentioned variables could predict the presence of aortic arch calcification with specificity of 93% (95% CI 78, 99%) and sensitivity of 53% (95% CI 34, 72%). The elastic and muscular arteries' stiffness mismatch was strongly associated with the extent of aortic arch calcification in this dialysis population and had better calcification predictive value compared to other demographic, hemodynamic and biochemical markers.

Abstract 13951: Circulating Inactive Matrix Gla-protein, Warfarin Use and Large Artery Stiffness in Heart Failure With Reduced Ejection Fraction

Background: large artery stiffness increases pulsatile afterload to the LV and is strongly predictive of adverse outcomes in heart failure and reduced ejection fraction (HFrEF). The identification of pathways related to arterial stiffness may provide novel therapeutic targets. Matrix Gla-protein (MGP) is a vitamin K-dependent protein that inhibits arterial calcification. Vitamin K deficiency leads to production of inactive non-phosphorylated and uncarboxylated MGP (dp-ucMGP). We hypothesized that greater levels of dp-ucMGP, indicating impaired MGP activation, are related to arterial stiffness in human HFrEF. Methods: We studied 50 subjects with HFrEF and 279 control subjects without HF. dp-ucMGP MGP was measured with ELISA (VitaK; The Netherlands). In a subgroup of subjects (34 with HFrEF and 146 with no HF), carotid-femoral PWV (a measure of large artery stiffness) was measured with arterial tonometry (Sphygmocor Device). Carotid-radial PWV, a measure of medium-sized muscular artery stiffness, was also measured. Results: Subjects with HFrEF demonstrated markedly increased levels of dp-ucMGP (654.7 vs. 426.8; P=0.004). Among subjects with HFrEF, warfarin use (standardized Beta 0.66; P&lt;0.0001) was the main predictor of dp-ucMGP. In turn, dp-ucMGP predicted carotid-femoral PWV (Beta=0.43; P=0.01) in HFrEF, even after adjustment for age, gender, mean arterial pressure and heart rate (Beta=0.43; P =0.007). In contrast, dp-ucMGP was not associated with carotid-radial PWV, a measure of muscular artery stiffness. Conclusions: HFrEF is associated with reduced levels of inactive dp-ucMGP, particularly in the setting of warfarin use. Circulating dp-ucMGP is independently associated with large artery stiffness in HFrEF, likely due to its role in vascular calcification. This suggests that deficient vitamin-K dependent activation of MGP may contribute to arterial stiffness in HFrEF and could be targeted with vitamin K supplementation and/or the use of anticoagulants other than warfarin. This hypothesis needs to be tested in future trials.

Intoxicação por sementes de pitombeira (Talisia esculenta) em um cão – relato de caso

A five-year-old mongrel bitch was admitted for acute care presenting neurological symptoms such as ataxia, muscular stiffness on forelimbs, pronounced depression, lethargy, weakness, incoordination, mydriasis and bilateral decreased pupillary reflex. Twelve hours post-admittance, the patient vomited both crushed and intact seeds of Talisia esculenta. Literature reports cases of sheep and cattle poisoning with similar symptoms by ingestion of fruits and leaves of T. esculenta. The aim of this article is to report this case, since no such records in companion animals are available.