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Biomedical subjects

N Ercoli

Publications and source records attributed to N Ercoli.

At least 19 recordsLinked to original sources

Schistosoma mansoni: neurotransmitters and the mobility of cercariae and schistosomules.

The concentration-dependent action of alkyl-isothiouroniums on Schistosoma mansoni cercariae, ranging from partial to total abolition of locomotor and flame cell movements, and/or suppression of virulence, is due to H1-histamine receptor inhibition. Correspondingly, H1-receptor inhibitors of widely different chemical structure, such as clemizol, diphenhydramine, brompheniramine, and promethazine, in 0.03-0.06 nM concentrations, induced an analogous cercarial immobilization reversed by addition of excess histamine. In contrast, the H2-receptor inhibitors cimetidine and metiamide did not immobilize cercariae. Histamine, acetylcholine, and serotonin, added to cercarial suspensions, showed no direct activity. Their participation in the mechanism of cercarial mobility was shown by the dose-dependent effects of antagonists, such as the serotonin antagonist methysergide and the acetylcholinesterase inhibitor physostigmine. These effects were not reversible by addition of serotonin and acetylcholine, respectively. A histamine-irreversible cercarial immobilization induced by the H-liberator 48/80 suggested that, besides H1-receptor inhibition, H-liberation and/or depletion also participated in mobility and survival. The detection of histamine in the cercaria corroborated the participation of histaminergic mechanisms. S. mansoni schistosomules collected from the mouse lung reacted to H1 antihistamines like cercariae, with a dose-dependent reduction of mobility and somatic deformation, such as vacuolization, granulation, and caecal enlargement.

Acetylcholine↗

Trypanostatic drug action: its relation to relapse following chemotherapy.

Analogies with dose-dependent transient prophylaxis and with delayed take of reinfection in drug-cleared Trypanosoma evansi (T. venezuelense) infected animals indicate that relapse following chemotherapy is induced by the same underlying mechanism, i.e., termination of the trypanostatic effect of residual drug concentrations. Correspondingly, both the complete ('true') prophylaxis and the radical cure without relapse require trypanocidal drug concentrations.

Animals↗

Antitrypanosomal activity of trivalent antimonials in vitro and its significance.

The SbIII preparations available for clinical use were compared in vitro for their concentration/time/effect curves on Trypanosoma venezuelense (T. evansi), measuring decrease of motility and of parasite numbers. With these two criteria leading to similar relative results, the drugs are classified into a rapidly acting group, led by sodium emetic (AST), followed by its dimethylcysteine chelate (NAP) and Anthiomaline, and a less and more slowly acting one: Triostam, Astiban and Stibophen. The relative activity of these drugs in vitro is parallel to that encountered against Schistosoma mansoni, attributed to a similar pattern of intracellular absorption. In vivo effectiveness may depend on bioavailability of Sb in the host and the direct action on the parasite, reflected by its in vitro activity. The interplay of these two factors leads to a different in vitro/in vivo activity relationship of the antimonials even in the same host (mouse) and to its variation in other host species.

Antimony↗

In vivo investigation of antibacterial ointments.

The clinically used topical antibiotic ointments, gentamicin 0.1%, oxytetracycline 3% w/polymyxin 0.1% and chloramphenicol 2% and an experimental preparation, 10-undecen-1-yl thiopseudourea iodide (AHR-1911) were studied for anti-infective action applied externally on the skin of mice inoculated subcutaneously with S. aureus and E. coli. In both infections statistically significant difference was encountered between curative and "clinical" healing rate in the case of the less effective preparations and/or dosages. The method appears suitable to establish and to compare the in vivo activity of ointments. This is not directly related to that of the aqueous drug solutions. AHR-1911, a powerful inhibitor of nucleic acid and protein synthesis, showed a bimodal action, with maximal effectiveness at 0.12-0.25% concentration, due presumably to the anti-inflammatory effect of higher concentrations. Direct evidence for the absorption of the drug from the application site was obtained using 14C labeled AHR-1911.

Abscess↗

[Clinical and experimental study on an anti-inflammatory preparation of topical use. The 10-undecentil-l-ll pseudothiourea (AHR-1911)].

Our previous studies led to the development of a drug, 10-undecen-1- pseudothiourea iodide (AHR-1911), with the characteristics of a broad spectrum of antibacterial-antimycotic action and anti-inflammatory properties in experimental lesions induced by burns, dextran, albumin, carrageenin and kaolin. Using different vehicles for topical use, these two types of therapeutic property were separated, yielding two pharmaceutical preparations with different indications. One is a 0,25% AHR-1911 preparation in a polyoxyethyleneglycol base, which in in vivo experiments has the antimicrobial efficacy of gentamycin ointment; the other, containing 10% AHR-1911 in a vanishing cream base with triethanolamine stearate, possesses the anti-inflammatory efficacy of the newer topical steroid preparations. The clinical data for this latter preparation agree with the experimental findings. Its activity in clinical conditions was found first by Di Prisco in dermatological cases and confirmed in contact dermatitis patients by Riobueno. Its usefulness in burns and contusions with excoriations, without a single instance of secondary infection was reported by Rojas Mratínez; its effectiveness in bursitis and tenosynovitis may extend its field of application beyond that of dermatology. Particularly impressive were the good results obtained in insect bites, due possibly to the antihistaminic effect of the drug acting synergistically with the anti-inflammatory one. In the experience of all the clinicians the preparation was very well tolerated.

Bacterial Infections↗