Nitric oxide (NO), a cellular signaling molecule, is produced in the brain by both neurons and astrocytes. While neurons are capable of rapid release of small amounts of NO serving as neurotransmitter, astrocytic NO production has been demonstrated mainly as a slow reaction to various stress stimuli. Little is known about the role of astrocyte-produced NO. Using the NO indicator 4,5-diaminofluorescein-2 diacetate (DAF-2DA) and acute slices from mouse brain, we distinguished neurons from astrocytes based on their different fluorescence kinetics and pattern, cellular morphology, electrophysiology, and responses to selective nitric oxide synthase (NOS) inhibitors. Typically, astrocytic fluorescence followed neuronal fluorescence with a delay of 1-2 min and was dependent on the inducible NOS isoform (iNOS) activity. Western blot analysis established the presence of functional iNOS in the neocortex. An assay for cell death revealed that most DAF-2DA-positive neurons, but not astrocytes, were damaged. Whole cell recordings from astrocytes confirmed that these cells maintained their membrane potential and passive properties during illumination and afterward. Induction of excitotoxicity by brief application of glutamate triggered an immediate and intense astrocytic response, while high-frequency electrical stimulation failed to do so. The present study demonstrates, for the first time, rapid and massive iNOS-dependent NO production by astrocytes in situ, which appears to be triggered by acute neuronal death. These data may bear important implications for our theoretical understanding and practical management of acute brain insults.

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Introduction: The ideal way of preparing patients for small-bowel capsule endoscopy has been controversial. Previous studies have shown that ingestion of 2 l of polyethylenglycol (PEG) 12 hours prior to capsule ingestion leads to improved visibility in comparison to no preparation at all. We speculated that using a post-ingestion (PI), booster-based cleansing protocol might provide an alternative to the PEG cleansing protocol. Methods: This randomized, blinded, prospective study enrolled 45 individuals. Patients were allocated to either of two groups. The PEG group ingested 2 l PEG 12 hours prior to the exam (n ¼ 22) and the PI group ingested one sachet of Picolax Õ dissolved in 250 ml of water one hour after swallowing the capsule with 500 ml of water (n ¼ 18). Primary endpoints were overall small bowel and distal third of small bowel cleansing levels. Secondary endpoints were average gastric and small-bowel transit time. Results: Forty-five patients participated in this study. Five individuals were excluded because of incomplete study. Percentage of patients with adequate visibility in the distal third of the small bowel in the PEG group was 9% vs 72% in the PI group (p < 0.0001). Average gastric time and total transit time were shorter in the PI group vs the PEG group (p ¼ 0.0065). Conclusion: Timing of ingestion of the PicolaxÕ purgative 60 minutes after swallowing the capsule endoscopy delivers better visibility in the distal third of the small bowel than the accepted cleansing protocol of ingesting 2 l PEG 12 hours prior to the capsule endoscopy procedure.

Context.— Medical education in pathology relies on the accumulation of experience gained through inspection of numerous samples from each entity. Acquiring sufficient teaching material for rare diseases, such as Hirschsprung disease (HSCR), may be difficult, especially in smaller institutes. The current study makes use of a previously developed decision support system using a decision support algorithm meant to aid pathologists in the diagnosis of HSCR. Objective.— To assess the effect of a short training session on algorithm-assisted HSCR diagnosis. Design.— Five pathologists reviewed a data set of 568 image sets (1704 images in total) selected from 50 cases by the decision support algorithm and were tasked with scoring the images for the presence or absence of ganglion cells. The task was repeated a total of 3 times. Each pathologist had to complete a short educational presentation between the second and third iterations. Results.— The training resulted in a significantly increased rate of correct diagnoses (true positive/negative) and a decreased need for referrals for expert consultation. No statistically significant changes in the rate of false positives/negatives were detected. Conclusions.— A very short (&lt;10 minutes) training session can greatly improve the pathologist's performance in the algorithm-assisted diagnosis of HSCR. The same approach may be feasible in training for the diagnosis of other rare diseases.