Inhibition of mucosal glycylsarcosine uptake by acetate in rat distal small intestine.

Acetate deriving from microbial fermentation may occur at considerable concentrations in the distal small intestine, where it appears to be absorbed by two different mechanisms: acetate-HCO3- exchange and non-ionic diffusion. Whether acetate affects absorption of other nutrients at this intestinal site is not known. Therefore the influence of acetate (30 mmol l-1) on oligopeptide absorption was studied using an in vitro mucosal uptake technique allowing measurement of substrate uptake across the brush border membrane (BBM). Acetate significantly inhibited mucosal uptake of 14C-labelled glycylsarcosine (Gly-Sar) at pH 6 and pH 7 in the presence of sodium. No inhibition occurred in the absence of sodium. Both acetate and the absence of sodium decreased Vmax of mucosal Gly-Sar uptake without substantially affecting the apparent Km value. Since it is well established that Vmax of peptide transport across the intestinal BBM depends on the size of the transmembrane H+ gradient as a driving force the present findings are in accordance with the assumption that acetate inhibits peptide absorption by attenuating the H+ gradient across the BBM, which depends on the presence of sodium.

Inhibition of antigen-induced muscle contractions by inhibitors of thromboxane pathway in rat small intestine.

Rats were sensitized against egg albumin and the response of the longitudinal muscle from the proximal small intestine to the antigen was tested. Egg albumin (1-100 micrograms/ml) concentration-dependently induced a contraction of the longitudinal muscle in tissues from sensitized animals but not from nonsensitized animals. The response to the antigen was resistant to neuronal blockers like tetrodotoxin, atropine and hexamethonium. Inhibitors of thromboxane synthesis such as the cyclooxygenase inhibitor, indomethacin, the thromboxane synthase blocker, 1-benzylimidazole, or the combined cyclooxygenase/lipoxygenase/thromboxane synthase inhibitor, sulfasalazine, inhibited the contraction evoked by egg albumin. A similar concentration-dependent inhibition of the antigen response was observed with two thromboxane A2 receptor blockers, SK&F 88046 and KW-3635. None of these blockers affected the response to the muscarinic agonist, carbachol, excluding unspecific effects of the drugs on smooth muscle contractility. The effect of antigen was reduced by the mast cell stabilizing agent, quercetin, and by the histamine H1 receptor blocker, mepyramin. These drugs, however, also inhibited the response to carbachol. When contractions were stimulated directly by the stable thromboxane derivative, carbocyclic thromboxane A2, the smooth muscle proved to be more than three orders of magnitude more sensitive to this agonist of the thromboxane pathway compared to histamine. Consequently, thromboxane A2 seems to be one of the main mediators of anaphylactically induced longitudinal muscle contractions in the rat small intestine.

[Total unilateral deafness in children. Etiologies and long-term consequences]. / Surdité unilatérale totale chez l'enfant. Etiologies et conséquences à long-terme.

A retrospective study of 72 children with a profound (average hearing loss > 90 dB) unilateral sensorineural hearing loss (PUSNHL) was carried out in the ENT department at the Rouen hospital in 1988 and 1994. This study intended to investigate the etiologies, how it was recognized, the age of the onset and the results of the medical evaluation of these PUSNHL. We found, in 2 cases, that vestibular lesions of the healthy ear were present before the onset of a hearing loss on this side, turning the PUSNHL into a bilateral deafness. We tried to correlate the etiologies, age of onset of the PUSNHL, status of the opposite ear and possible scholar problems in the group of the 42 children followed-up for more than 2 years (mean follow-up time = 7 years). Among children suffering from PUSNHL, we specified a group with higher risk of school failures, allowing ENT physicians to propose more accurate management to these children.

[Recurrent laterocervical suppurations. Role of fistulae and cysts of the 4th branchial pouch]. / Suppurations latéro-cervicales récidivantes. Rôle des fistules et kystes de la 4e poche branchiale.

Four cases of fistula of fourth branchial pouch are used as a basis for a description of the two possible clinical pictures: left cervical suppuration in a neonate with respiratory distress or recurrent cervical cellulitis in an older child or young adult usually diagnosed as a suppurative thyroiditis. Diagnostic features are outlined and emphasis placed on the need for an adapted surgical excision originating at the pharyngeal orifice of the fistula. In two of the four cases reported its trajectory was between muscle and mucosa planes and then in contact with the cricothyroid joint as a small cord, otherwise unidentifiable.