Influence of dopaminergic treatment on resting elbow joint angle control mechanisms in patients with Parkinson's disease - a preliminary report.

PURPOSE: Heightened tonic stretch reflex contributes to increased muscle tone and a more-flexed resting elbow joint angle (EJA) in patients with Parkinson's disease (PD). Dopaminergic medication restores central nervous system (CNS) functioning and decreases resting muscle electrical and mechanical activities. This study aimed to evaluate the effects of dopaminergic medication on parkinsonian rigidity, resting EJA, resting electrical activity (electromyography, EMG) and mechanical properties (myotonometry, MYO) of elbow flexor muscles and the associations of EJA with these muscles resting electrical activity and mechanical properties in PD patients. We also evaluated a relationship between dopaminergic treatment dose and these outcome measures values. METHODS: Ten PD patients (age 68 ± 10.1 years; body mass 70 ± 16.8 kg; height 162 ± 6.6 cm; illness duration 9 ± 4.5 years) were tested during medication on- and off-phases. Resting EJA, myotonometric muscle stiffness (S-MYO) and root mean square electromyogram amplitude (RMS-EMG) were recorded from relaxed biceps brachii and brachioradialis muscles. Based on the above parameters, we also calculated the EJA/S-MYO ratio and EJA/RMS-EMG ratio. Parkinsonian rigidity was assessed using the motor section of the Unified Parkinson's Disease Rating Scale. RESULTS: EJA, EJA/S-MYO ratio, and EJA/RMS-EMG ratio were increased and S-MYO, RMS-EMG, and parkinsonian rigidity were decreased during the medication on-phase compared with the off-phase. In addition, the dopaminergic treatment dose was negatively correlated with S-MYO and RMS-EMG, and positively correlated with EJA/SMYO and EJA/RMS-EMG ratios. CONCLUSIONS: We conclude that dopaminergic medication- induced improvements in resting elbow joint angle in tested patients with PD are related to changes in their muscle electrical and mechanical properties.

Spike shape analysis of electromyography for parkinsonian tremor evaluation.

INTRODUCTION: Standard electromyography (EMG) parameters have limited utility for evaluation of Parkinson disease (PD) tremor. Spike shape analysis (SSA) EMG parameters are more sensitive than standard EMG parameters for studying motor control mechanisms in healthy subjects. SSA of EMG has not been used to assess parkinsonian tremor. This study assessed the utility of SSA and standard time and frequency analysis for electromyographic evaluation of PD-related resting tremor. METHODS: We analyzed 1-s periods of EMG recordings to detect nontremor and tremor signals in relaxed biceps brachii muscle of seven mild to moderate PD patients. RESULTS: SSA revealed higher mean spike amplitude, duration, and slope and lower mean spike frequency in tremor signals than in nontremor signals. Standard EMG parameters (root mean square, median, and mean frequency) did not show differences between the tremor and nontremor signals. CONCLUSIONS: SSA of EMG data is a sensitive method for parkinsonian tremor evaluation.

Baseline platelet indices and bleeding after transcatheter aortic valve implantation.

Bleeding complications are frequent and independently predict mortality after transcatheter aortic valve implantation (TAVI). It has been demonstrated that certain platelet parameters are indicative of platelet reactivity. We sought to determine the possible correlation between simple platelet indices and bleeding complications in patients undergoing TAVI. Platelet indices--platelet count, mean platelet volume (MPV), platelet distribution width and plateletcrit--were measured in 110 consecutive patients on the day preceding TAVI. In-hospital bleeding events after TAVI were assessed according to the Valve Academic Research Consortium-2 classification as any bleeding, major and life-threatening bleeding (MLTB) and need for transfusion. By receiver-operating characteristic analysis, only MPV was able to distinguish between patients with and without any bleeding [area under the curve (AUC) 0.629, 95% confidence interval (CI) 0.531-0.719, P = 0.0342], MLTB (AUC 0.730, 95% CI 0.637-0.811, P = 0.0004) and need for transfusion (AUC 0.660, 95% CI 0.563-0.747, P = 0.0045). By multivariate logistic regression, high MPV (>10.6) and low platelet distribution width (<14.8) were associated with increased risk of any bleeding [odds ratio (OR) 4.08, 95% CI 1.66-10.07, P = 0.0022; and OR 3.82, 95% CI 1.41-10.36, P = 0.0084, respectively] and MLTB (OR 10.76, 95% CI 3.05-38, P = 0.0002; and OR 8.46, 95% CI 1.69-42.17, P = 0.0092, respectively). Additionally, high MPV independently correlated with the need for transfusion (OR 4.11, 95% CI 1.71-9.86, P = 0.0016). Larger and less heterogenic platelets may be associated with increased risk of short-term bleeding complications after TAVI.

Electromyogram features during linear torque decrement and their changes with fatigue.

PURPOSE: Surface electromyogram (EMG) spike shape analysis (SSA) has recently been proposed as an adjunct tool to EMG time and frequency domain analysis to increase our knowledge of motor unit (MU) control strategies. The study was aimed to understand more in MU deactivation strategy during torque decrement, and its possible changes in fatigued muscle, using a combination of traditional time and frequency domain analysis and SSA techniques. METHODS: EMG was detected from the biceps brachii of 11 untrained male subjects during static down-going ramp contractions (90-0% of the maximal voluntary contraction, MVC) under non-fatigued (DGR) and fatigued (FDGR) conditions. The root mean square (RMS) and mean frequency (MF), as well as SSA parameters, were calculated on 1-s EMG windows centred on each 10 % MVC step for both conditions. RESULTS: In both the DGR and FDGR EMG-RMS, mean spike amplitude and mean spike slope decreased by 50 % in the 90-60 % MVC. The mean spike frequency also decreased by 50 % in the 30-10 % MVC. Except the "mean number of spikes per second" all the other estimated EMG parameters were significantly different during FDGR compared to DGR. CONCLUSION: The dynamics of EMG parameters during torque decrement would support a MU deactivation strategy which relies more on MU de-recruitment in the high % MVC range and more on firing rate reduction in the low % MVC range. The adopted integrated approach to EMG signal processing could indicate that SSA is an important tool to disclose alterations in motor control due to fatigue.

Effects of submaximal eccentric exercise on muscle activity at different elbow joint angles.

Our study aimed to determine whether electrical and mechanical factors contributing to acute or long-term maximal torque reduction and muscle soreness due to submaximal eccentric exercise (ECC) are elbow-joint-angle specific and to what extent the joint angle affects the contribution of antagonist coactivation to this torque reduction. Maximal isometric torque (MIT), muscle soreness assessment, agonist electromechanical activities, and antagonist coactivation during the maximal voluntary contraction (MVC) were measured at elbow joint angles of 60°, 90°, and 150° before ECC, immediately after exercise, and 24, 48, 72, and 120 hr after exercise. ECC causes an immediate decrease in MIT as well as increased antagonist coactivation at three angles. Antagonist coactivation returned to its baseline level at 24 hr regardless of joint angle. The most rapid torque recovery and the highest force level at which pain occurred were found after ECC at a joint angle of 60°. During the recovery period, no mechanomyographical changes were observed when measuring surface mechanomyography changes at three angles, while the electrical activity differed between angles.

Twitch mechanical properties after repeated eccentric exercise of the elbow flexors.

The purpose of this study was to assess if the protective adaptation after eccentric exercise affects changes of twitch contractile properties of the biceps brachii muscle. Maximal isometric torque (MVC), twitch contractile properties, muscle soreness, and relaxed elbow angle (RANG) assessments were measured in 12 untrained, right-handed male volunteers (age, 23 ± 2 years; height, 182 ± 5 cm; mass, 75 ± 7 kg) before, immediately after, 48 h, and 120 h following each bout of eccentric exercise that consisted of 30 repetitions of lowering a dumbbell adjusted to 75% of each individual's maximal isometric torque of the right elbow flexors. MVC, peak twitch torque, maximal rate of twitch torque development, maximal rate of relaxation, muscle soreness, and RANG changes were significantly attenuated after the second bout of eccentric exercise when compared with the first bout. In contrast, time to twitch peak torque and half relaxation time did not change significantly after both the first and the second bout. The findings indicate that the mechanisms responsible for rapid adaptation affect some twitch mechanical properties such as peak torque, maximal rate of torque development, and maximal rate of relaxation but not time to peak torque and half relaxation time.

Results of liver transplantation in the Department of General, Transplant and Liver Surgery at the Medical University of Warsaw in patients with chronic hepatitis B and C viruses infection.

INTRODUCTION: Cirrhosis related to hepatitis C virus (HCV) and hepatitis B virus (HBV) infection is the most frequent indication for liver transplantation worldwide. Progress in prophylaxis of posttransplant HBV recurrence has led to major improvements in long-term outcomes of patients after liver transplantation. Conversely, impaired posttransplant survival of patients with HCV infection was reported in several studies, mainly due to recurrence of viral infection. The purpose of this study was to compare long-term results of liver transplantation between patients with HBV monoinfection, HCV monoinfection and HBV/HCV coinfection. MATERIAL AND METHODS: A total of 1090 liver transplantations were performed in the Department of General, Transplant and Liver Surgery in cooperation with the Department of Immunology, Internal Medicine, and Transplantology at the Transplantation Institute Medical University of Warsaw between December 1994 and May 2012. After exclusion of patients with cirrhosis of non-viral etiology, patients with malignant tumors, and patients with acute liver failure, the final study cohort comprised 209 patients with HBV (HBV+/HCV- subgroup; n = 56) or HCV (HBV-/HCV+ subgroup; n = 119) monoinfection or HBV/HCV coinfection (HBV+/HCV+; n = 34). These subgroups of patients were compared in terms of long-term results of transplantations, defined by 5-year patient and 5-year graft survival estimates. RESULTS: Overall and graft survival rates after 5-years for the whole study cohort were 74.5% and 72.6%, respectively. Five-year overall survival was 70.4% for patients within the HBV+/HCV- subgroup, 77.8% for patients within the HBV-/HCV+ subgroup, and 68.5% for patients within the HBV+/HCV+ subgroup. The corresponding rates of graft survival were 67.0%, 76.3%, and 68.5% for patients within the HBV+/HCV-, HBV-/ HCV+, and HBV+/HCV+ subgroups, respectively. Observed differences were non-significant, both in terms of overall (p = 0.472) and graft (p = 0.461) survival rates. CONCLUSIONS: Both overall and graft survival rates after liver transplantations performed in the Department of General, Transplant and Liver Surgery in cooperation with the Department of Immunology, Internal Medicine, and Transplantology at the Transplantation Institute Medical University of Warsaw in patients with HBV and HCV infection are comparable to those reported by other European and American centers. In contrast to other studies, obtained results do not confirm the negative impact of HCV infection on long-term outcomes of patients.

1000 liver transplantations at the Department of General, Transplant and Liver Surgery, Medical University of Warsaw--analysis of indications and results.

THE AIM OF THE STUDY: was to analyze indications and results of the first one thousand liver transplantations at Chair and Clinic of General, Transplantation and Liver Surgery, Medical University of Warsaw. MATERIAL AND METHODS: Data from 1000 transplantations (944 patients) performed at Chair and Clinic of General, Transplantation and Liver Surgery between 1994 and 2011 were analyzed retrospectively. These included 943 first transplantations and 55 retransplantations and 2 re-retransplantations. Frequency of particular indications for first transplantation and retransplantations was established. Perioperative mortality was defined as death within 30 days after the transplantation. Kaplan-Meier survival analysis was used to estimate 5-year patient and graft survival. RESULTS: The most common indications for first transplantation included: liver failure caused by hepatitis C infection (27.8%) and hepatitis B infection (18%) and alcoholic liver disease (17.7%). Early (< 6 months) and late (> 6 months) retransplantations were dominated by hepatic artery thrombosis (54.3%) and recurrence of the underlying disease (45%). Perioperative mortality rate was 8.9% for first transplantations and 34.5% for retransplantations. Five-year patient and graft survival rate was 74.3% and 71%, respectively, after first transplantations and 54.7% and 52.9%, respectively, after retransplantations. CONCLUSIONS: Development of liver transplantation program provided more than 1000 transplantations and excellent long-term results. Liver failure caused by hepatitis C and B infections remains the most common cause of liver transplantation and structure of other indications is consistent with European data.

Similar response of agonist and antagonist muscles after eccentric exercise revealed by electromyography and mechanomyography.

The purpose of this study was to investigate the influence of eccentric contractions (ECC) on the biceps (BB) and triceps brachii (TB) muscles during maximal voluntary contraction (MVC) of elbow flexors using electrical (EMG) and mechanomyographical activities (MMG). Each of 18 male students performed 25 submaximal contractions (50% MVC) of the elbow flexors. Root mean square amplitude (RMS) and median frequency (MDF) were calculated for the EMG and MMG signals recorded during MVC. All measurements were taken before, immediately after, 24, 48, 72, and 120 h post-ECC from the BB and TB muscles. MVC was reduced by 34% immediately after exercise and did not return to the resting value within 120 h (P0.05). The EMG MDF decreased significantly (P< or =0.05) in both muscles after ECC. The MMG RMS at 24h, 48, 72 and 120 h post-ECC was significantly lower compared to that recorded immediately after ECC in both muscles (P< or =0.05). The present research showed that (i) there were similar changes in electrical and mechanical activities during MVC after submaximal ECC in agonist and antagonist muscles suggesting a common drive controlling the agonist and antagonist motoneuron pool, (ii) the ECC induced different changes in EMG than in MMG immediately after ECC and during 120 h of recovery that suggested an increased tremor and contractile impairments, i.e., reduced rate of calcium release from the sarcoplasmic reticulum (acute effect), and changes in motor control mechanisms of agonist and antagonist muscles, and increased muscle stiffness (chronic effect).