[Endoscopic approach in HIV infected-patients with upper gastrointestinal symptoms].

Unlabelled: Upper gastrointestinal symptoms such as nausea, vomiting, upper abdominal pain, heartburn, early satiety, bloating and anorexia, are frequently reported by HIV positive patients; however, their prevalence and diagnostic approach are unknown.

Aims: To evaluate the frequency of endoscopic and histologic diagnosis in HIV positive patients with upper gastrointestinal symptoms referred to upper endoscopy, and to compare them with those found in a non-HIV infected group with similar symptoms.

Patients And Methods: Out of 132 HIV positive patients referred to upper endoscopy, 102 (75%) with upper gastrointestinal symptoms, and 177 non-HIV controls were prospectively included.

Imidazole H3-antagonists: relationship between structure and ex vivo binding to rat brain H3-receptors.

H3-antagonists possess promising pharmacological effects on awakening, learning and memory, but few data on their access to the central nervous system (CNS) have been reported so far. The purpose of this work was to investigate the relationships between structure and brain penetration of a series of H3-antagonists, using ex vivo binding experiments in rats. H3-antagonists belonging to different chemical classes but all having an imidazole ring, an alkyl spacer, a polar fragment and a lipophilic ending group, were selected among the numerous H3-antagonists recently described by us.

Synthesis, biological activity, QSAR and QSPR study of 2-aminobenzimidazole derivatives as potent H3-antagonists.

We report the design, synthesis, QSPR and QSAR of a new class of H(3)-antagonists, having a 2-aminobenzimidazole moiety connected to the 4(5) position of an imidazole ring through di- or tri-methylene chains. Eleven substituents, selected by experimental design to obtain broad and non-correlated variation in their lipophilic, electronic and steric properties, were introduced at the 5(6) position of the benzimidazole nucleus. The compounds were tested for their H(3)-receptor affinity, by displacement of [(3)H]-(R)-alpha-methylhistamine ([(3)H]-RAMHA) binding to rat brain membranes (pK(i)), for intrinsic activity, evaluating their effect on [(35)S]GTPgammaS binding to rat brain membranes, and for H(3)-antagonist potency, on electrically stimulated guinea-pig ileum (pK(B)).

Synthesis and biological evaluation of GABA derivatives able to cross the blood-brain barrier in rats.

Two new GABA derivatives, 1 and 2, were synthesized and tested for their capacity to display CNS activity, which was assessed by determining the effects on the duration of pentobarbital-induced hypnosis in rats. Compound 1, peripherally injected, significantly prolonged the hypnosis time, a typical GABA-mimetic effect, while both intracerebroventricular and intravenous administration of compound 2 surprisingly shortened the hypnotic effect in an atropine-sensitive way. The study was extended also to compounds 1a, 1b and 2a, putative oxidative/hydrolytic metabolites of 1 and 2.

The role of HB-donor groups in the heterocyclic polar fragment of H3-antagonists. I. Synthesis and biological assays.

It has been recently reported that compounds composed of an imidazole connected through an alkyl spacer to a 2-aminobenzimidazole showed high affinity towards the H(3)-receptor. The guanidine fragment of the 2-aminobenzimidazole is probably involved in hydrogen bond interactions at the binding site, and is referred to as the 'polar fragment'. In the present work, starting from 2-aminobenzimidazole derivatives with a di-methylene spacer 1 (pK(i)=7.