Assessment of the Effects of Endocrine Disrupting Compounds on the Development of Vertebrate Neural Network Function Using Multi-electrode Arrays.

Bis-phenols, such as bis-phenol A (BPA) and bis-phenol-S (BPS), are polymerizing agents widely used in the production of plastics and numerous everyday products. They are classified as endocrine disrupting compounds (EDC) with estradiol-like properties. Long-term exposure to EDCs, even at low doses, has been linked with various health defects including cancer, behavioral disorders, and infertility, with greater vulnerability during early developmental periods. To study the effects of BPA on the development of neuronal function, we used an in vitro neuronal network derived from the early chick embryonic brain as a model. We found that exposure to BPA affected the development of network activity, specifically spiking activity and synchronization. A change in network activity is the crucial link between the molecular target of a drug or compound and its effect on behavioral outcome. Multi-electrode arrays are increasingly becoming useful tools to study the effects of drugs on network activity in vitro. There are several systems available in the market and, although there are variations in the number of electrodes, the type and quality of the electrode array and the analysis software, the basic underlying principles, and the data obtained is the same across the different systems. Although currently limited to analysis of two-dimensional in vitro cultures, these MEA systems are being improved to enable in vivo network activity in brain slices. Here, we provide a detailed protocol for embryonic exposure and recording neuronal network activity and synchrony, along with representative results.

Technical tips: MRI compatible EEG electrodes: advantages, disadvantages, and financial feasibility in a clinical setting.

Magnetic resonance imaging (MRI) compatible EEG electrodes have been produced and available on the market for the past several years, however their feasibility from a clinical standpoint remains unknown. Two hundred plus questionnaires were sent out to practicing epilepsy and trauma centers across the United States and Canada to evaluate the advantages and disadvantages of these electrodes as well as their financial feasibility in a clinical setting. 30% of the surveys returned were from clinical sites utilizing MRI compatible EEG recording electrodes. From these results we were able to understand the advantages and disadvantages of utilizing such recording media and their financial feasibility in the workplace.

Twenty-four hour pH monitoring in the assessment of esophageal function.

Ambulatory 24-hour esophageal pH monitoring is an important test in the management of patients with gastroesophageal reflux disease. It quantifies esophageal acid exposure while patients pursue their everyday activities without restrictions. The test is performed with a compact portable data logger, miniature pH electrode, and computerized data analysis. The pH electrode should be positioned 5 cm above the manometrically defined lower esophageal sphincter. The patient is asked to press a button on the data logger indicating the onset of the symptom in question, which allows symptoms and acid reflux correlation. Twenty-four hour pH monitoring is generally performed after a therapeutic trial of antireflux medications, preferably proton pump inhibitors.

Modelo numérico para detecçäo de tumores / Numerical model to detect tumor

A intenção deste trabalho é a de sugerir um modelo numérico para a detecção de tumores em regiões do corpo humano. Assim, empregando a técnica dos dois eletrodos (TDE) na região em teste (RET), indica-se o Método dos Elementos Finitos (MEF), associado com um método probabilístico, para predizer o espalhamento dos potenciais elétrico medidos (calculados). Muitos eventos aleatórios afetam os potenciais e, devido a isto, o resultado do método numérico empregado (diagnóstico) caracteriza a probabilidade de detecção do tumor no ser humano.

Electrical methods for skin moisture assessment.

Skin sites on 8 test subjects were treated with moisturizers, and different electrical measuring methods were compared regarding their quality in the assessment of the induced changes in the stratum corneum hydration level. Low frequency susceptance measurements were found preferable to high frequency admittance measurements, and the advantages of monopolar measurements with the three-electrode system are described.

Success of re-use of cardiac electrode catheters.

The feasibility of cardiac electrode catheter re-use was prospectively evaluated over a 5-year period (1981 to 1986), during which time 178 catheters were used 1,526 times for 847 electrophysiologic procedures. Detailed records of catheter testing and use were maintained. No complications were encountered during the study period. All re-used catheters functioned for cardiac pacing and electrographic recording. Surveillance cultures and biologic indicators revealed that adequate sterilization procedures were used. Thus, electrode catheters may be safely re-used provided a thorough cleaning, testing and record-keeping system is instituted. This may result in lower patient cost (approximately $30 per re-use vs [200 per single use) for electrophysiologic catheterization.