Dissociation of visual, motor and predictive signals in parietal cortex during visual guidance

The role of the posterior parietal cortex (PPC) in the visual guidance of movements was studied in monkeys trained to use a joystick to guide a spot to a target. Visual and motor influences were dissociated by transiently occluding the spot and by varying the relationship between the direction of joystick and spot movements. We found a strong segregation of function in PPC during visual guidance. Neurons in area MST were selectively modulated by the direction of visible moving stimuli, whereas neurons in area MIP were selectively modulated by the direction of hand movement. In contrast, the selectivity of cells in the lateral intraparietal area (LIP) did not directly depend on either visual input or motor output, but rather seemed to encode a predictive representation of stimulus movement. These predictive signals may be an important link in visuomotor transformations.     

Factors affecting aerosol performance during nebulization with jet and ultrasonic nebulizers

Nebulization of aqueous solutions is a convenient delivery system to deliver drugs to the lungs because it can produce droplets small enough to reach the alveolar region. However, the droplet size might be affected by the changes in the temperature and the concentration of the nebulizing solution in the reservoir during nebulization. In this study, the changes in the droplet size over the nebulization time using a PariBoy air-jet and a Multisonic ultrasonic nebulizer have been studied. The findings were related to changes in the temperature, concentration, surface tension, viscosity and saturated vapour pressure of the nebulizing solution. By using the jet nebulizer, an increase in the droplet size followed by a decrease has been observed. This observation could be attributed to the approx. 7 degrees C reduction of the temperature during the first 2 min in the jet nebulizer reservoir which increased the viscosity of the nebulizing solution. After this initial period of time, the increasing drug concentration induced a reduction of the surface tension and, consequently, a decrease in the droplet size. However, with the ultrasonic nebulizer a temperature increase of approx. 20 degrees C during the first 6 min in the nebulizing solution was observed leading to a decrease in droplet size, viscosity and surface tension and an increasing saturated vapour pressure. This again led to smaller average droplet sizes.     

Stereotactic pallidotomy performed without using microelectrode guidance in patients with Parkinson's disease: surgical technique and 2-year results

OBJECT: Pallidotomy for the treatment of medically refractory Parkinson's disease (PD) has enjoyed renewed popularity. However, the optimal surgical technique, lesion location, and long-term effectiveness of pallidotomy remain subjects of debate. In this article the authors describe their surgical technique for performing pallidotomy without using microelectrode guidance, and the clinical and radiological results of this procedure. METHODS: Patients were evaluated preoperatively by using a battery of validated clinical rating scales and magnetic resonance (MR) imaging of the brain. Individuals with severe treatment-refractory idiopathic PD who were believed to be good candidates for surgery underwent computerized tomography scanning- and MR imaging-guided stereotactic pallidotomy. Intraoperative macrostimulation was used to optimize lesion placement and to avoid injury to nearby structures. Lesion location and size were calculated from MR imaging sequences of the brain obtained within the first 24 hours after surgery and again 3 months later. Clinical examinations were conducted at 1.5, 3, 6, 12, and 24 months after surgery. Seventy-five patients (mean age 61 years, range 38-79 years) underwent unilateral pallidotomy. Significant improvements were observed in the "off' period scores for the activities of daily living portion of the Unified Parkinson's Disease Rating Scale (UPDRS), the UPDRS motor scores, total "on" time, levodopa-induced dyskinesias, and contralateral tremor. These improvements were maintained 24 months postoperatively. The mean lesion volume measured on the immediate postoperative MR image was 73 +/- 5.4 mm3. Radiological analysis suggests that initial lesion volume does not predict outcome. The only permanent major complication was a single visual field defect. CONCLUSIONS: Pallidotomy performed without using microelectrode guidance is a safe and effective treatment for selected patients with medically refractory PD.     

Assessment of the efficacy of group counselling using cognitive approach on knowledge,attitude, and decision making of pregnant women about modes of delivery

The choice of casarean deliveries by mothers is highly influenced by inadequate knowldge and negative attitudes towards vaginal birth. In this semi-experimental study, we compared knowledge, attitude, and decision making about modes of delivery between nulliparous pregnant women who received eight sessions of group consultation and those who took routine prenatal education. Contrary to the control group, the improvement of knowledge and attitudes were significant in the consultation group (p < 0.001), as well as mothers' decisions for vaginal birth (p = 0.03). Group consultation is an appropriate approach to improving knowledge, attitudes, and tendencies of mothers toward natural birth.     

Non-invasive endotracheal delivery of paclitaxel-loaded alginate microparticles

Aerosolized chemotherapeutics leads to higher, localized and continuous concentrations of active agents in lung tissue with lower side effects for other organs. The present study was performed on jugular vein cannulated rats which endothracheally received 4 mg/kg of free paclitaxel powder (Free-PTX), paclitaxel-loaded alginate microparticles (PTX-ALG-MPs) and i.v. paclitaxel (Anzatax^®). Pharmacokinetic parameters for Free-PTX and PTX-ALG-MPs contain higher AUC, mean residence time (MRT),half-life and bioavailability, with lower elimination constant (k_e). Statistical analysis showed that the amount of paclitaxel per gram of lung tissue after 0.5, 6 and 24 h after administration of Free-PTX was lower than PTX-ALG-MPs. Lung tissue AUC for Free-PTX was lower than PTX-ALG-MPs. According to the obvious advantages obtained, such as dose lowering and increasing paclitaxel residence time and half-life. It should be noted that cell cytotoxicity test on normal airway cell lines was not examined in this study but due to previous reports on safety of inhaled paclitaxel, it can be suggested that pulmonary delivery of paclitaxel can be a useful non-invasive route of administration compared with i.v administration.     

Cost-Effectiveness of Endovascular Versus Open Repair of Abdominal Aortic Aneurysm: A Systematic Review

Cardiovascular Drugs and Therapy - Abdominal aortic aneurysm (AAA) is a life-threatening condition which, in the absence of increasing diameter or rupture, often remains asymptomatic, and a...