The use of memantine in dementia with Lewy bodies

OBJECTIVE: To determine the effect of memantine in the treatment of Dementia with Lewy Bodies (DLB). BACKGROUND: While memantine has been used to successfully treat moderate-to-severe Alzheimer's disease (AD) and some non AD dementias, no reports are available regarding the effect of the drug on DLB. METHODS: We reviewed the charts of 11 subjects with DLB by McKeith Criteria that were prospectively evaluated and treated with memantine (with or without cholinesterase inhibitors (ChEIs)) for varying lengths of time. RESULTS: 9 of 11 DLB subjects on memantine were also on ChEIs. Seven of eleven were stable or improved with memantine while the remaining four worsened or responded adversely when exposed to the drug. No adverse effects on motor function were observed. CONCLUSIONS: Memantine can be used safely in patients with DLB, but its symptomatic effects may be variable.     

Deep Brain Stimulation of Caudal Zona Incerta for Parkinson's Disease: One-Year Follow-Up and Electric Field Simulations

ObjectiveTo evaluate the effects of bilateral caudal zona incerta (cZi) deep brain stimulation (DBS) for Parkinson's disease (PD) one year after surgery and to create anatomical improvement maps based on patient-specific simulation of the electric field.Materials and MethodsWe report the one-year results of bilateral cZi-DBS in 15 patients with PD. Patients were evaluated on/off medication and stimulation using the Unified Parkinson's Disease Rating Scale (UPDRS). Main outcomes were changes in motor symptoms (UPDRS-III) and quality of life according to Parkinson's Disease Questionnaire-39 (PDQ-39). Secondary outcomes included efficacy profile according to sub-items of UPDRS-III and simulation of the electric field distribution around the DBS lead using the finite element method. Simulations from all patients were transformed to one common magnetic resonance imaging template space for the creation of improvement maps and anatomical evaluation.ResultsMedian UPDRS-III score off medication improved from 40 at baseline to 21 on stimulation at one-year follow-up (48%, p < 0.0005). PDQ-39 summary index did not change, but the subdomain activities of daily living (ADL) and stigma improved (25%, p < 0.03 and 75%, p < 0.01), whereas communication worsened (p < 0.03). For UPDRS-III sub-items, stimulation alone reduced median tremor score by 9 points, akinesia by 3, and rigidity by 2 points at one-year follow-up in comparison to baseline (90%, 25%, and 29%, respectively, p < 0.01). Visual analysis of the anatomical improvement maps based on simulated electrical fields showed no evident relation with the degree of symptom improvement and neither did statistical analysis show any significant correlation.ConclusionsBilateral cZi-DBS alleviates motor symptoms, especially tremor, and improves ADL and stigma in PD patients one year after surgery. Improvement maps may be a useful tool for visualizing the spread of the electric field. However, there was no clear-cut relation between anatomical location of the electric field and the degree of symptom relief.     

Randomized Comparison of a 90 uF Capacitor Three-electrode Defibrillation System with a 125 uF Two-electrode Defibrillation System

Introduction: A variety of factors, including the number of defibrillation electrodes and shocking capacitance, may influence the defibrillation efficacy of an implantable defibrillator system. Therefore, the purpose of this study was to compare the defibrillation energy requirement using a 125 uF two-electrode defibrillation system and a 90 uF three-electrode defibrillation system.Methods and Results: The defibrillation energy requirements measured with both systems were compared in 26 consecutive patients. The two-electrode system used a single transvenous lead with two defibrillation coils in conjunction with a biphasic waveform from a 125 uF capacitor. The three-electrode system used the same transvenous lead, utilized a pectoral implantable defibrillator generator shell as a third electrode, and delivered the identical biphasic waveform from a 90 uF capacitor. The two-electrode system was associated with a higher defibrillation energy requirement (10.8&plusmn;5.5 J) than was the three-electrode system (8.9&plusmn;6.7 J, p &lt; 0.05), however, the leading edge voltage was not significantly different between systems (361&plusmn;103 V vs. 397&plusmn;123 V, P &equals; 0.07). The two-electrode system also had a higher shocking resistance (49.0&plusmn;9.0 ohms vs. 41.4&plusmn;7.3 ohms, p &lt; 0.001) and a lower peak current (7.7&plusmn;2.6 A vs. 10.1&plusmn;3.7 A, p &lt; 0.001) than the three-electrode system.Conclusions: A three-electrode defibrillation system that utilizes a dual coil transvenous lead and a subcutaneous pectoral electrode with lower capacitance is associated with a lower defibrillation energy requirement than is a dual coil defibrillation system with higher capacitance. This finding suggests that the utilization of a pectoral generator as a defibrillation electrode in conjunction with smaller capacitors is a more effective defibrillation system and may allow for additional miniaturization of implantable defibrillators.     

Mesenchymal Stem Cells in Combination with Scaffolds for Bone Tissue Engineering

This article reviews past and current strategies of the use of bone graft substitutes along with the future biologic alternatives that can enhance the functional capabilities of those grafts. Many of these bone graft substitute alternatives include ceramic-based, allograft-based, factor-based and polymer-based whereas others are cell-based. The ways of achieving the goal of tissue engineering using stem cells and their lineage to regenerate tissue have been detailed with regard to both the generation of sufficient vascular invasion of the tissue to improve oxygen and nutrient supply, and the development of innovative physical/chemical stimuli to induce bone formation with the proper biomaterial to carry the cells. It is imperative to integrate basic polymer science with molecular biology and stem cell biology, in the design of new materials that perform very sophisticated signaling needed for integration and function.