We present an endomicroscope apparatus that exhibits out-of-focus background rejection based on wide-field illumination through a flexible imaging fiber bundle. Our technique, called HiLo microscopy, involves acquiring two images, one with grid-pattern illumination and another with standard uniform illumination. An evaluation of the image contrast with grid-pattern illumination provides an optically sectioned image with low resolution. This is complemented with high-resolution information from the uniform illumination image, leading to a full-resolution image that is optically sectioned. HiLo endomicroscope movies are presented of fluorescently labeled rat colonic mucosa.

Objective: Food

The expression and distribution of TTX-sensitive voltage-gated sodium channel (VGSC) alpha subunits in the enteric nervous system (ENS) has not been described. Using RT-PCR, expression of Na(v)1.2, Na(v)1.3, Na(v)1.6, and Na(v)1.7 mRNA was detected in small and large intestinal preparations from guinea pigs. Expression of Na(v)1.1 mRNA as well as Na(v)1.1-like immunoreactivity (-li) were not observed in any intestinal region investigated. Na(v)1.2-li was primarily observed within the soma of the majority of myenteric and submucosal neurons, although faint immunoreactivity was occasionally observed in ganglionic and internodal fibers. Na(v)1.3-li was observed in dendrites, soma, and axons in a small group of myenteric neurons, as well as in numerous myenteric internodal fibers; immunoreactivity was rarely observed in the submucosal plexus. Na(v)1.6-li was primarily observed in the initial axonal segment of colonic myenteric neurons. Na(v)1.7-li was observed in dorsal root ganglia neurons but not in the myenteric plexus of the small and large intestine. In the ileum, 37% of Na(v)1.2-li cell bodies colocalized with calbindin-li while colocalization with calretinin-li was rare. In contrast, 22% of Na(v)1.3-li cell bodies colocalized with calretinin-li but colocalization with calbindin-li was not observed. In the colon, both Na(v)1.2-li and Na(v)1.3-li cell bodies frequently colocalized with either calretinin-li or calbindin-li. Na(v)1.2-li cell bodies also colocalized with the majority of NeuN-li cells in the small and large intestine. These data suggest that Na(v)1.1 may not be highly expressed in the ENS, but that Na(v)1.2, Na(v)1.3, and Na(v)1.6, and possibly Na(v)1.7, have broadly important and distinct functions in the ENS.

Background Decreased gallbladder smooth muscle (GBSM) contractility is a hallmark of cholesterol gallstone disease, but the interrelationship between lithogenicity, biliary stasis and inflammation are poorly understood. We studied a mouse model of gallstone disease to evaluate the development of GBSM dysfunction relative to changes in bile composition and the onset of sterile cholecystitis. Methods BALB/cJ mice were fed a lithogenic diet for up to 8 weeks, and tension generated by gallbladder muscle strips was measured. Smooth muscle Ca2+ transients were imaged in intact gallbladder. Key Results Lipid composition of bile was altered lithogenically as early as one week, with increased hydrophobicity and cholesterol saturation indexes; however, inflammation was not detectable until the fourth week. Agonist-induced contractility was reduced from weeks 2 through 8. GBSM normally exhibits rhythmic synchronized Ca2+ flashes, and their frequency is increased by carbachol (3μM). After one week, lithogenic diet-fed mice exhibited disrupted Ca2+ flash activity, manifesting as clustered flashes, asynchronous flashes or prolonged quiescent periods. These changes could lead to a depletion of intracellular Ca2+ stores, which are required for agonist-induced contraction, and diminished basal tone of the organ. Responsiveness of Ca2+ transients to carbachol was reduced in mice on the lithogenic diet, particularly after 4-8 weeks, concomitant with appearance of mucosal inflammatory changes. Conclusions & Inferences These observations demonstrate that GBSM dysfunction is an early event in the progression of cholesterol gallstone disease and that it precedes mucosal inflammation.

Balemba OB, Bartoo AC, Nelson MT, Mawe GM. Role of mitochondria in spontaneous rhythmic activity and intracellular calcium waves in the guinea pig gallbladder smooth muscle.

The purpose of this study was to characterize the effects of glucose-dependent insulinotropic peptide (GIP) on small intestinal glucose transport in vitro. Stripped proximal jejunum from fasted mice was mounted in Ussing chambers. The serosal side was bathed in Regular Ringer solution containing 5 mmol/l glucose, and the mucosal side, with solution containing 10 mmol/l 3-O-methyl glucose (3OMG). Intercellular cyclic adenosine monophosphate (cAMP), mucosa-to-serosa fluxes of 3OMG (J ms 3OMG ), and short-circuit current (I SC ) were measured in the presence and absence of GIP. GIP increased cAMP by 2.5-fold in isolated enterocytes, consistent with a direct effect of GIP on these epithelial cells. GIP also increased I SC and J ms 3OMG by 68 and 53%, respectively, indicating that the increase in J ms 3OMG was primarily electrogenic, with a small electroneutral component. The stimulatory effect of GIP on J ms 3OMG was concentration dependent. In addition, 1,000 nmol/l and 10 nmol/l GIP increased J ms 3OMG by 70 and 30% over control, respectively, consistent with receptor activation. Phlorizin (20 μmol/l), an inhibitor of Na + -glucose cotransporter (SGLT-1), abolished the increase in I SC and decreased J ms 3OMG by ~65%. These results indicate that stimulation of SGLT-1 activity by GIP partially accounts for the increase in J ms 30MG. These studies are the first to demonstrate direct stimulation of intestinal glucose transport by GIP independent of its insulinotropic properties. GIP stimulates cellular accumulation of cAMP and thereby upregulates glucose transport. The GIP-induced increase in glucose transport appears to be mediated, at least in part, by SGLT-1.

We investigated the 5.3 percentage point increase in the prevalence of food insecurity in Canada between the National Population Health Survey of 1998–99 and the Canadian Community Health Survey of 2000–01. We found that the increase in food insecurity occurred disproportionately in households in the western provinces, particularly Alberta, and among homeowners rather than renters. Inter-provincial variation in heating cost inflation explained as much as 61 percent of the inter-provincial variation in food insecurity increases between 1998 and 2001.

In this paper, we describe the design of a microfluidic sample preparation chip for human stool samples infected with Clostridium difficile. We established a polymerase chain reaction able to distinguish C. difficile in the presence of several other organisms found in the normal intestinal flora. A protocol for on-chip extraction of nucleic acids from clinical samples is described that can detect target DNA down to 5.0×10−3 ng of template. The assay and sample preparation chip were then validated using known positive and known negative clinical samples. The work presented has potential applications in both the developed and developing world.