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M Tonini

Publications and source records attributed to M Tonini.

At least 127 records · Page 7Linked to original sources
PubMedDate not supplied

Recent advances in the pharmacology of gastrointestinal prokinetics.

Gastrointestinal prokinetics promote or increase the coordination of the gut wall contractions leading to enhancement of propulsive motility and, consequently, caudal displacement of luminal contents. Currently, they are considered drugs of choice for the treatment of upper gastrointestinal tract functional motor disorders such as those associated with gastrooesophageal reflux disease, chronic dyspepsia, gastroparesis (idiopathic or secondary to other diseases) and acute or chronic idiopathic intestinal pseudo-obstruction. The aim of the present review is to give an outline of the pharmacology of currently available prokinetics and of novel drugs endowed with gastrointestinal prokinetic action that require further pharmacological and/or clinical testing. The novel drugs include recent generations of benzamide and non-benzamide 5-HT4 receptor agonists, motilin receptor agonists, and inhibitors of nitric oxide synthase. Furthermore, based on our improved knowledge of the role of 5-HT in emesis and gastrointestinal motility, the therapeutic potential of potent mixed 5-HT4 agonists--5-HT3 antagonists in the control of cytotoxic-drug-induced emesis and associated gut motor disturbances will be discussed. Lastly, a section of this review deals with the colon as a possible target for the action of prokinetics.

Animals↗
PubMedDate not supplied

Low-amplitude propagated contractile waves: a relevant propulsive mechanism of human colon.

BACKGROUND: Human colonic motility is still poorly understood, especially as far as concerns its propulsive function. Available data refer almost exclusively to the forceful propulsive activity, which is recognized as high-amplitude propagated contractions, the manometric equivalent of mass movements. By contrast, information on less vigorous propulsive contractions is still lacking. AIMS: To investigate the presence and behaviour of low-amplitude propagated contractile waves (less than 50 mmHg in amplitude) in the colon of healthy humans during a 24-hour study period. SUBJECTS AND METHODS: A series of 16 healthy volunteers of both sexes entered the study, and were investigated by a standard technique involving a colonoscopically-positioned manometric catheter. During the study, two standard 1,000 kcal mixed meal and a 450 kcal breakfast were served. The recordings were, therefore, scanned for the presence of low-amplitude propagated contractile waves (waves of less than 50 mmHg in amplitude, propagated over at least three consecutive recording ports), their daily distribution, and their relationship with physiological events. RESULTS: Low-amplitude propagated contractile waves were constantly present in all the tracings, with an average of about 61 events/subject/day and a mean amplitude of about 20 mmHg. More than 80% of these events appeared during the day, with a significant (p<0.05) increase after meals and after morning awakening. In 25% of subjects, these waves were accompanied by emission of flatus. CONCLUSIONS: In the human colon, low-amplitude propagated contractile waves are a constant physiological propulsive pattern, which is generally related to sleep-wake cycles and meal ingestion.

Adult↗
PubMedDate not supplied

Cholinergic contractions induced by GABA-A receptor activation in the guinea-pig ileum are inhibited by alpha-chymotrypsin and potentiated by diazepam.

The influence of alpha-chymotrypsin and diazepam on the phasic (mainly direct) and tonic (indirect, probably substance P-mediated) components of intestinal cholinergic contractions, induced by the GABA-A receptor agonist 3-aminopropane sulphonic acid (3-APS), was investigated in the guinea-pig ileum. alpha-Chymotrypsin, at a concentration (20 U/ml) not affecting submaximal Ach (0.1 microM) contractions, preferentially depressed the tonic component of the 3-APS (30 microM)-induced response. A brief exposure (10 or 60 sec) to diazepam (0.1 microM) potentiated both the phasic and the tonic contractions evoked by low (10, 30 microM) 3-APS concentrations. This potentiation was prevented by bicuculline (30 microM), hyoscine (1 microM) and flumazenil (1, 3 microM). These results provide further support for an involvement of a peptide neurotransmitter on GABA-A receptor-mediated cholinergic response in the ileum. The modulation of this response by diazepam is probably exerted through recognition sites resembling the "central type" benzodiazepine receptors.

Acetylcholine↗
PubMedDate not supplied

Toxicology and health impact of environmental exposure to boron. A review.

The presence of high concentrations of boron in community water supplies has been reported as a localized problem in certain areas of United States, USSR and Italy. In this paper, current information on sources, occurrence, pollution potential and toxicity of environmental boron is reviewed. In animals, chronic low-level boron exposure has been shown to cause reduced growth, cutaneous disorders and suppression of male reproductive system function. The mechanisms underlying these effects and available data on dose-response relationships are discussed in connection with human health hazards possibly associated with continuous low-level absorption of boron compounds.

Adult↗
PubMedDate not supplied

Human toxicology of boron with special reference to boric acid poisoning.

The improper use of boric acid containing antiseptics is still one of the most common causes of toxic accidents in newborns and infants. Health hazards may also arise from inadvertent absorption of insecticides and household products containing borates as well as from occupational accidents related to production and use of boranes. A variety of boronated agents with hypolipidemic, antiinflammatory or anticancer properties have been developed in recent years. Unfortunately, most of these compounds were found to be highly toxic when tested at the required therapeutic dosages in animals. In this paper, recent information on human toxicology of boron is reviewed, with special emphasis on epidemiological and clinical aspects of boric acid poisoning.

Adult↗