Analyses of human colonic mucus obtained by an in vivo sampling technique.

BACKGROUND: The mucus layer is an important dynamic component of the epithelial barrier. It contains mucin glycoproteins and other compounds secreted by the intestinal epithelium, such as secretory IgA. However, a standardized in vivo sampling technique of mucus in humans is not yet available. AIM: To assess the validity and feasibility of mucin and protein determinations in human colonic mucus collected under physiological conditions. SUBJECTS AND METHODS: Triplicate colonic mucus samples were collected in 11 healthy volunteers using cytology brushes during sigmoidoscopy. As an indication of the quantity of collected mucus, total protein and mucin concentrations were determined by measuring oligosaccharide equivalents and monosaccharides. Also secretory IgA and sialic acid concentrations were determined and proteomic analysis was performed using surface enhanced laser desorption/ionization-time of flight-mass spectrometry. RESULTS: Mean values of secretory IgA and sialic acid corrected for the amount of mucus ranged from 0.16 to 1.81 g secretory IgA/mmol oligosaccharide equivalents and from 12.6 to 48.6g sialic acid/mmol oligosaccharide equivalents. Proteomic analysis of mucus is feasible and cluster analysis showed subject specific profiles. CONCLUSION: Using cytology brushes, human colonic mucus can be sampled and under physiological conditions. These samples could give information on the composition and quality of the mucus layer.

Activation of an adrenergic and vagally-mediated NANC pathway in surgery-induced fundic relaxation in the rat.

The aim of this study was to pharmacologically characterize and investigate the possible contribution of adrenergic and nonadrenergic noncholinergic (NANC) pathways involved in the relaxation of the rat gastric fundus following abdominal surgery. Using an intragastric balloon, the effect of skin incision (SI), laparotomy (LT) and manipulation of the small intestine followed by caecal resection (M + R) on fundic pressure was evaluated. SI resulted in a brief relaxation of the gastric fundus abolished by guanethidine and blocked by hexamethonium and the combination of phentolamine, propranolol and atropine (PPA). LT induced a longer lasting relaxation which was abolished by guanethidine and hexamethonium. It was blocked by PPA and the combination of ganglionectomy and vagotomy, but unaffected by atropine, vagotomy or ganglionectomy. M + R induced a long-lasting relaxation which was only partly blocked by guanethidine or PPA, illustrating an inhibitory NANC component. Vagotomy combined with guanethidine completely abolished the relaxation following M + R, whereas it was significantly blocked by hexamethonium and the combination of ganglionectomy with vagotomy. These results indicate that SI, LT and M + R induce inhibition of fundic motility via an adrenergic mechanism. During M + R, an additional vagally mediated inhibitory NANC pathway is activated. Finally, we suggest that LT and M + R inhibit the gastric fundus via both a splanchnic and a vagal reflex pathway.

Nicotinic acetylcholine receptor blocking effect of guanethidine in the rat gastric fundus.

1 Guanethidine is commonly used as a drug to investigate adrenergic neurotransmission and, in combination with atropine, to realize non-adrenergic non-cholinergic (NANC) conditions. Previous studies suggested a nicotinic acetylcholine receptor blocking effect of guanethidine. Therefore, we investigated the effect of increasing concentrations of guanethidine (0.1-100 microM) on nicotine-induced relaxations of longitudinal muscle strips of rat gastric fundus. 2 In the presence of 1 microM atropine and 3 microM guanethidine, nicotine (30 microM) induces a fast and sustained relaxation which is partly inhibited by the nitric oxide synthase inhibitors Nomega-nitro-L-arginine (L-NOARG) and Nomega-nitro-L-arginine methyl ester (L-NAME) (both 30 and 100 microM). One microM tetrodotoxin (TTX) completely blocks this nicotine-induced relaxation. 3 High concentrations of guanethidine (> or =10 microM), but not adrenoceptor blockade by the alpha-adrenoceptor antagonist phentolamine in combination with the beta-adrenoceptor antagonist nadolol (both 3 microM), inhibit the nicotine-induced relaxation. 4 Guanethidine (0.1-100 microM) has no effect on relaxations induced by electrical field stimulation (EFS; 1-8 Hz), nitric oxide (NO; 0.01-1 microM), vasoactive intestinal polypeptide (VIP; 0.1-10 nM) or isoprenaline (1-10 nM). 5 We conclude that high concentrations of guanethidine (> or =10 microM) block nicotine-induced NANC relaxations of longitudinal muscle strips of the rat gastric fundus most likely at the level of the nicotinic acetylcholine receptor.

Mild closed head injury in children compared to traumatic fractured bone; neurobehavioural sequelae in daily life 2 years after the accident.

UNLABELLED: Two years after an accident resulting in either a mild head injury or a fractured bone, two groups of 22 children each, aged 4-14 years, were examined for the existence of any neurobehavioural symptoms by means of a standardized questionnaire filled out by their caretakers. Selection of the children was based on reports of the Accident and Emergency Department in 1 year. Significantly more symptoms were reported after mild head injury. The main symptoms reported were headache, dizziness, fatigue and memory problems. The total number of symptoms in the children with mild head injury exceeded four times this in the group of children with a fractured bone. CONCLUSION: Even 2 years after a mild head injury there are still residual symptoms in daily life.

Correlates of anesthetic properties in isolated spinal cord: cyclobutanes.

Two halogenated cyclobutanes, one anesthetic and one not, were compared on receptor-specific pathways in isolated neonatal rat spinal cord. The anesthetic 1-chloro-1,2,2-trifluorocyclobutane depressed the monosynaptic reflex (glutamate non-NMDA receptors) and abolished a slow ventral root potential (glutamate NMDA, non-NMDA and tachykinin receptors). This compound slightly enhanced the muscimol-evoked dorsal root potential (GABAA) but reversibly depressed the dorsal root potential elicited by dorsal root stimulation. The non-anesthetic 1,2-dichlorohexafluorocyclobutane increased monosynaptic reflex, depressed slow ventral root potential approximately 50%, had little effect on muscimol-evoked dorsal root potential, and irreversibly depressed dorsal root-evoked dorsal root potential. Hypoxia accounts for slow ventral root potential depression, but not monosynaptic reflex enhancement. In this preparation and for this pair of compounds, anesthetic properties are related to blockade of transmission at glutamate synapses, with a small component of GABAA enhancement. Monosynaptic reflex increase may be related to the non-anesthetic cyclobutane's convulsant and anti-anesthetic properties.

Spermatogenesis and the role of Sertoli cells in the freshwater snail Biomphalaria glabrata.

The various stages of spermatogenesis and the Sertoli cells of Biomphalaria glabrata were studied with histochemical and electron microscope techniques. During spermatogenesis a manchette of microtubules is formed around the nucleus and the mid-piece of the spermatids. This manchette becomes helically coiled and probably plays an important role in the spiralisation of the nucleus and of the mitochondrial sheath. During spermatogenesis so-called chromatoid bodies (CB) occur, which consist of arginine-rich proteins. These CB disintegrate during the early spermatid stage. The results suggest that the CB are either involved in histone transition or in the formation of microtubules. The remaining cytoplasm of the spermatids is phagocytised by the Sertoli cells. Apparently this process of phagocytosis is an important part of the mechanism of spermiation. Morphological measurements of the Sertoli cells showed that the relative volume of most organelles decrease during spermatogenesis, indicating a general decrease in cell activity. Possible functions of the Sertoli cells, such as transportation and nutrition of spermatogenic cells and hormone production, are discussed. It is concluded on the basis of the histochemical and ultrastructural observations that the Sertoli cells are involved in the nutrition of spermatogenic cells. It seems unlikely that they are hormone producing cells.