Exposure to cerebrospinal fluid of sporadic amyotrophic lateral sclerosis patients alters Nav1.6 and Kv1.6 channel expression in rat spinal motor neurons.

Cerebro Spinal Fluid (CSF) from patients with ALS has been documented to have a toxic effect on motor neurons both in vivo and in vitro. Here we show that the CSF from Amyotrophic Lateral Sclerosis (ALS) patients (ALS-CSF) has the potential to perturb ion channel expression, specifically the Na(v)1.6, and K(v)1.6 channels in newborn rat spinal motor neurons both in vivo and in vitro. ALS-CSF and CSF from nonALS patients (nonALS-CSF) were intrathecally injected into 3-day-old rat pups at the rate of 1 microl/2.5 min using a microinjector. In addition, embryonic rat spinal cord cultures were also exposed to 10% ALS or nonALS-CSF on the 9th day in vitro (9DIV) in serum free DMEM medium. After 48 h of CSF exposure, the cultures and the spinal cord sections were processed for immunostaining of the above mentioned ion channels. We observed a decrease in the expression of Na(v)1.6 and K(v)1.6 channels in motor neurons in ALS-CSF treated group, and the presence of trophic factors like Brain Derived Neurotrophic Factor (BDNF) and Ciliary Neurotrophic Factor CNTF partially reversed the effects produced by ALS-CSF. Altered expression of these voltage-gated channels may interfere with the electrical activity of motor neurons, and thereby lead to the degeneration of neurons.

Utility of esophageal biopsy in the diagnosis of nonerosive reflux disease.

This study evaluated the accuracy of esophageal biopsy for the diagnosis of nonerosive reflux disease (NERD) in adults. Thirty-five patients with reflux symptoms and a normal endoscopy were prospectively evaluated using esophageal biopsies, 24-h ambulatory pH monitoring and symptomatic response 4 weeks after an increase in antireflux therapy. Biopsies were scored for the total number of typical histologic reflux features seen. Patients were considered to have NERD if both pH-metry was positive and step-up therapy was successful. Biopsies were then compared to this predefined gold standard. Biopsy was most sensitive (62%) but poorly specific (27%) when one or more histologic reflux features were seen. A threshold of three or more histologic features improved the specificity (91%) but reduced sensitivity (31%). Response to step-up therapy was associated with 100% sensitivity and 100% negative predictive value when compared to biopsy and pH-metry as an alternate combined gold standard. In conclusion, biopsy is insensitive in diagnosing NERD but reasonably specific if three or more typical histologic reflux features are present.

Polymer-coated gelatin capsules as oral delivery devices and their gastrointestinal tract behaviour in humans.

In oral delivery of protein and peptide drugs there is a great need for suitable devices for delivering the therapeutic agent-incorporated microspheres selectively in the intestine. It is essential that the drug-loaded multiple unit carrier system should be protected from the harsh environment of the stomach and deliver the carrier system in the large intestine where drug action or absorption is desired. Gelatin capsules were coated with various concentrations of sodium alginate and cross-linked with appropriate concentrations of calcium chloride and tested in vitro for resistance to gastric and intestinal medium. Gelatin capsules coated with 20% w/v of the polymer which gave the most promising result in vitro were evaluated in human volunteers for their in vivo gastro intestinal tract behaviour. The radiographical studies show that while the uncoated gelatin capsules disintegrated in the stomach within 15 min of ingestion, the alginate coated gelatin capsules remained intact as long as they were retained in the stomach (up to 3 h) and then migrated to the ileocecal region of the intestine and disintegrated.

Controlled release of anticancer drug methotrexate from biodegradable gelatin microspheres.

Biodegradable hydrophilic gelatin microspheres containing the anticancer drug methotrexate (MTX) of different mean particle sizes (1-5, 5-10, and 15-20 microns) were prepared by polymer dispersion technique and crosslinked with glutaraldehyde. The microspheres were uniform, smooth, solid and in the form of free-flowing powder. About 80 per cent of MTX was incorporated in gelatin microspheres of different sizes. The in vitro release of MTX was investigated in two different media, namely simulated gastric and intestinal fluids. The release profiles indicated that gelatin microspheres released MTX in a zero-order fashion for 4-6 days in simulated gastric fluid and for 5-8 days in simulated intestinal fluid. The rate of release of MTX decreased with increase in the particle size of the microspheres. MTX release was faster in gastric fluid when compared to intestinal fluid.