sepharose and Central-Nervous-System-Diseases

The goal of this study was to validate a simple, inexpensive, and robust model system to be used as an in vitro surrogate for in vivo brain tissues in preclinical and exploratory studies of infusion-based intraparenchymal drug and cell delivery.. Agarose gels of varying concentrations and porcine brain were tested to determine the infusion characteristics of several different catheters at flow rates of 0.5 and 1 microl per minute by using bromophenol blue (BPB) dye (molecular weight [MW] approximately 690) and gadodiamide (MW approximately 573). Magnetic resonance (MR) imaging and videomicroscopy were used to measure the distribution of these infusates, with a simultaneous measurement of infusion pressures. In addition, the forces of catheter penetration and movement through gel and brain were measured. Agarose gel at a 0.6% concentration closely resembles in vivo brain with respect to several critical physical characteristics. The ratio of distribution volume to infusion volume of agarose was 10 compared with 7.1 for brain. The infusion pressure of the gel demonstrated profiles similar in configuration and magnitude to those of the brain (plateau pressures 10-20 mm Hg). Gadodiamide infusion in agarose closely resembled that in the brain, as documented using T1-weighted MR imaging. Gadodiamide distribution in agarose gel was virtually identical to that of BPB dye, as documented by MR imaging and videomicroscopy. The force profile for insertion of a silastic catheter into agarose gel was similar in magnitude and configuration to the force profile for insertion into the brain. Careful insertion of the cannula using a stereotactic guide is critical to minimize irregularity and backflow of infusate distribution.. Agarose gel (0.6%) is a useful surrogate for in vivo brain in exploratory studies of convection-enhanced delivery.

Topics: Animals; Bromphenol Blue; Central Nervous System Diseases; Cerebral Cortex; Coloring Agents; Drug Administration Routes; Drug Delivery Systems; Gels; Infusions, Intralesional; Magnetic Resonance Imaging; Phantoms, Imaging; Pressure; Sepharose; Swine

To demonstrate oligoclonal IgG bands (I) in unconcentrated cerebrospinal fluid, we used isoelectric focusing in agarose followed by protein transfer to cellulose nitrate membrane, double-antibody peroxidase labeling, and avidin-biotin amplification. I can be reliably seen after isoelectric focusing of 5-microL specimens containing 125 ng of IgG (25 mg/L). Thus the technique is more sensitive than others (e.g., silver staining) and more reliable than radioimmunofixation. When we used this technique with fluids from 62 patients with multiple sclerosis and infectious disease of the central nervous system, 84% displayed I, a percentage not increased when the same specimens were concentrated to 3.5 g of IgG per liter, examined by agarose isoelectric focusing, and stained with Coomassie Blue. Results for 53 patients with tension headache and psychoneurosis were all negative. By obviating the need to concentrate samples of cerebrospinal fluid the present method is a useful, sensitive alternative for demonstrating I.

Topics: Avidin; Biotin; Central Nervous System Diseases; Collodion; Fluorescent Antibody Technique; Humans; Immunoenzyme Techniques; Immunoglobulin G; Indicators and Reagents; Infections; Isoelectric Focusing; Multiple Sclerosis; Rosaniline Dyes; Sepharose