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Biomedical subjects

S Banfi

Publications and source records attributed to S Banfi.

At least 19 recordsLinked to original sources
PubMed1995

Pharmacologic evaluation of the calcitonin analogue SB 205614 in models of osteoclastic bone resorption in vitro and in vivo: comparison with salmon calcitonin and elcatonin.

The activity of a novel calcitonin SB 205614 was compared with salmon calcitonin (sCT) and (Asu1,7)-eel calcitonin (ELC) in six different models of osteoclastic bone resorption in vitro and in vivo. SB 205614 is an ELC analogue that has an acetylenic bridge instead of the natural disulphide bridge, rendering the molecule more stable biologically than sCT and equally stable to ELC. Our aim was to determine whether this structural change compromised biologic activity, and if not, whether the increased stability could be used to exploit novel modes of administration. In the in vitro assays of pit formation by disaggregated rat osteoclasts on cortical bone slices (DROcA) and PTH stimulation of 45Ca-release from prelabeled fetal rat bone, no significant differences in activity were observed between the three calcitonins. In the DROcA, IC50s of 0.003, 0.015 and 0.064 pg/ml for sCT, ELC, and SB 205614, respectively, were determined, with total or near complete inhibition observed at 1 pg/ml (0.3 pM). In the assay of PTH-stimulation of 45Ca release, IC50s were measured of 5.5, 4.8, and 12.9 pM for sCT, ELC, and SB 205614, respectively; in every case maximal inhibition (ca. 80%) was observed at 30 and 100 pM. The internationally approved U.S. Pharmacopoeia bioassay of hypocalcemia in the rat following intravenous (IV) administration indicated that SB 205614 had a greater potency than ELC or sCT. More important, a full dose-hypocalcemic response curve demonstrated significantly increased potency compared to sCT or ELC, as the doses causing 15% lowering of serum calcium (approximately 50% of the maximum effect) were 33.9, 25.2, and 12.9 mg/kg for sCT, ELC, and SB 205614, respectively. As a preliminary means of investigating alternative delivery forms of calcitonin, the time course of the hypocalcemic effect was investigated in the rat and rabbit following IV administration, and was compared with that following intranasal (IN) administration (rat and rabbit), and following intracolonic administration (rat only). Maximal effects were similar, whereas in general the hypocalcemic effect of SB 205614 was of a longer duration than the other two calcitonins; this was reflected in a larger area over the curve (AOC). However, following IN administration in the rabbit, where an aerosol delivery device similar to that used in the clinic was used to administer the calcitonins, SB 205614 (100 IU/kg) induced a highly significant two-fold increase in the AOC compared to ELC or sCT. The calcitonins were also compared in assays designed to measure therapeutic efficacy in the rat.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed1995

Has spinocerebellar ataxia type 2 a distinct phenotype? Genetic and clinical study of an Italian family.

The gene for spinocerebellar ataxia type 2 (SCA2) is mapped to chromosome 12q23-24.1. Using D12S79 and D12S105, we performed linkage analysis in nine individuals including six affected members of a four-generation family in which we excluded SCA1 by direct mutation analysis. We obtained a lod score = 2.37 at theta = 0.00 for the compound haplotype. The clinical picture appeared homogeneous, showing the absence of corticospinal signs and the presence of peripheral neuropathy. The present study suggests that this SCA2 family is clinically different from most SCA1 families.

Adult↗
PubMed1992

Oxiracetam antagonizes the disruptive effects of scopolamine on memory in the radial maze.

The effects exerted by oxiracetam on the disruption of performance induced by scopolamine in the radial arm maze were investigated in overtrained rats. Scopolamine induced a dose-related decrease in the efficiency of responding and an increase of running time. The effect of the SC injection of 0.2 mg/kg scopolamine on the efficiency of responding was antagonized by the IP administration of 30 mg/kg oxiracetam, while the effect on running time induced by the same dose of scopolamine was not. Physostigmine (0.3 mg/kg SC) antagonized both effects of 0.2 mg/kg scopolamine. Methylscopolamine, at the dose of 0.2 mg/kg SC, was devoid of any effect on both parameters. Increasing the dose of methylscopolamine to 0.63 mg/kg did cause serious peripheral effects which eventually prevented some animals from completing the task. Similar peripheral effects were observed after administration of 0.63 mg/kg scopolamine. The effects of this dose of scopolamine on efficiency and running time were not antagonized by pretreatment with 100 mg/kg oxiracetam. Oxiracetam alone (30 or 100 mg/kg IP) did not modify the performance of previously trained rats. The present results suggest that oxiracetam selectively restores cholinergic mechanisms which are involved in learning and memory.

Animals↗
PubMed1989

Brain entry and direct central pharmacological effects of the nootropic drug oxiracetam. Oxiracetam: brain entry and pharmacological effects.

Oxiracetam administered systemically to rats as a 14C radiolabelled drug (200 mg/kg p.o. or 100 mg/kg intra-artery) enters the brain and is found unmetabolized above all in some of the brain areas functionally involved in the modulation of cognitive processes. Among the brain areas examined, the largest amount of compound was recovered in septum, followed by hippocampus; a smaller amount was found in cerebral cortex and striatum. 14C oxiracetam administered directly into the lateral ventricles of the brain presented a similar pattern of distribution, indicating that the tropism of the drug for the above brain areas does not depend on its route of administration. The amounts of oxiracetam that could reach the brain after systemically administered pharmacologically active doses were also estimated. These amounts (1.9 to 19 nmols/rat) were delivered through a permanently implanted cannula, into the lateral ventricles of the brains of conscious, freely moving rats. In this experimental condition oxiracetam dose-dependently antagonized the amnesia induced by scopolamine (0.66 mg/kg s.c.). The above findings clearly indicate that oxiracetam enters the brain and directly exerts its pharmacological activity there.

Administration, Oral↗
PubMed1987

Determination of vinyl chloride monomer residue in poly(vinyl chloride) at the parts-per-billion level with an automatic purge-and-trap technique.

A method for the determination of vinyl chloride residue in poly(vinyl chloride) using a commercial purge-and-trap ancillary unit has been developed. Concentrations lower than 10 ppb (10(9] with relative standard deviations in the region of 10% in up to 24 samples are detectable with fully automatic operation without operator attendance. With multiple extraction of the same sample an external standard is used; the matrix does not have any influence on the recovery of vinyl chloride.

Chromatography, Gas↗
PubMed1986

Experimental behavioral studies with oxiracetam on different types of chronic cerebral impairment.

Oxiracetam (4-hydroxy-2-oxo-1-pyrrolidine acetamide) is a novel compound effective in improving learning and memory in normal animals as well as in animals with acute cerebral impairment induced by a variety of noxious stimuli (i.e., electroshock, neurodepressants, metabolic inhibitors, hypoxia). In accordance with a stepwise approach to the pharmacological studies, the compound was also tested in rats with chronic cerebral impairment due to aging, cerebrovascular lesions, and congenital microencephaly. To evaluate the brain telencephalic functions, the learning rate of two conditioned avoidance responses using the pole climbing test and the performance in a multiple-choice water maze were considered. Oxiracetam at doses ranging from 10 to 60 mg/kg i.p. improved the learning rate of these animals with impaired cognitive functions. The compound was active also by oral administration.

Aging↗
PubMed1986

Effect of oxiracetam and piracetam on central cholinergic mechanisms and active-avoidance acquisition.

Oxiracetam at 100 and 300 mg/kg i.p. dose levels increased acetylcholine (ACh) utilization in the rat cerebral cortex and hippocampus. ACh utilization was assessed by measuring, with a gas chromatographic method, the decrease in ACh level after inhibiting its synthesis by 15 micrograms intracerebroventricularly (i.c.v.) injection of hemicholinium (HC-3). ACh steady state levels were not affected. Piracetam (300 mg/kg i.p.) also increased ACh utilization in the hippocampus. Repeated daily administration of oxiracetam 100 mg/kg i.p. caused a 31% increase in high-affinity choline uptake (HACU) in the hippocampus. A single administration of 300 mg/kg i.p. of oxiracetam and piracetam also increased HACU rate in the hippocampus. However, the effect of piracetam was over within 3 h, while 3 h after its administration oxiracetam still caused a 40% increase in HACU rate. Oxiracetam (100 mg/kg i.p.) significantly antagonized the impairment in the acquisition of an active-avoidance conditioned response (pole climbing) associated with the inhibition of ACh synthesis by HC-3. These results indicate that oxiracetam enhances the activity of the septohippocampal cholinergic pathways, and to a lesser extent, of the cortical cholinergic network.

Acetylcholine↗
PubMed1984

Cyclic GABA-GABOB analogues. IV. Activity on learning and memory.

A number of N-substituted 4-hydroxy-, 4-acyloxy- and 4-alkoxy-2-pyrrolidinones were examined by a screening method predictive of their activity on cognitive processes. The 1-aminocarbonylmethyl-substituted compounds showed a favorable effect on learning and memory, and among them the most active was the 4-hydroxy derivative, oxiracetam, which had a potency considerably higher than piracetam, used for comparison purposes.

Amnesia↗
PubMed1984

Methylazoxymethanol microencephaly in rats: neurochemical characterization and behavioral studies with the nootropic oxiracetam.

The administration of methylazoxymethanol (MAM) to pregnant rats induced a marked reduction in the weight of the offspring's brain. This reduction was due to aplasia of the cortex and hippocampus, whose thicknesses were 50% of those of control animals. A significant reduction was also observed in the striatum. This aplasia could be ascribed to the antimitotic effect of MAM, which, when given at gestational day 15, prevented the development of neurons in the three brain areas mentioned. Indeed, we infer here that the total number of GABA-receptor complexes, as measured by [3H]muscimol and [3H]flunitrazepam binding, was reduced to the same degree as was the weight of the cortex. Similarly, total [3H]haloperidol binding sites were reduced in the striatum. From the behavioral point of view, offspring of MAM-treated rats (MAM rats) showed impaired acquisition in the water-maze and pole-climbing tests, indicating that this brain aplasia had disrupted cognitive processes. In contrast, these animals showed normal growth, and grossly their behavior appeared normal. Oxiracetam, a new compound that belongs to the recently described class of nootropic drugs, was able to restore acquisition processes in MAM rats. We propose therefore that MAM rats might become an interesting and quite simple animal model for evaluation of new acquisition-enhancing drugs. Moreover, this model could also be useful to study the neurochemical correlates of cognitive processes.

Abnormalities, Drug-Induced↗
PubMed1983

Experimental chronic epilepsy in rats: a screening method for antiepileptic drugs.

Rats were rendered epileptic by subpial injection of an FeCl3 solution. Epileptiform discharges, recorded by chronically implanted extradural electrodes, were evident within 48 h of surgery and persisted for more than 6 months. It is demonstrated that this model is useful for studying new antiepileptic agents since a series of clinically effective drugs (diazepam, clonazepam, Na phenobarbital, primidone, carbamezepine, ethosuximide, diphenylhydantoin, Na valproate, GABOB) show an activity which is does-dependent and within a range satisfactorily related to human dosages.

Animals↗
PubMed1982

A screening method for substances potentially active on learning and memory.

A series of substances from different pharmacological classes was examined by two different tests for their activity on learning and memory. A concomitant evaluation was performed by use of a one-trial passive avoidance immediately followed by electroshock in mice and the pole-climbing test in rats. Only doses not producing changes in gross behavior (Irwin's test) were used. A facilitating action on all the considered parameters was observed for d-amphetamine, caffeine, L-glutamine, Mg pemoline, phosphorylserine, piracetam, strychnine, and tricyanoaminopropene. A worsening action was found for atropine, cycloheximide, diazepam, and morphine. Chlorpheniramine, diphenylhydantoin, GABA, imipramine, meclizine, mescaline, metrazol, and testosterone showed no or doubtful activity. Our results suggest that the parallel use of these relatively simple tests supplies information that is satisfactory for screening purposes and that has a high degree of predictability as substantiated by literature data.

Animals↗
PubMed1977

Synthesis and antiinflammatory activity of 3-chloro-4-cyclopropylmethoxyphenylacetic acid and its alpha-methyl homologue.

The synthesis of 3-chloro-4-cyclopropylmethoxyphenylacetic acid (I) from 3-chloro-4-hydroxyacetophenone (III) by the etherification with cyclopropylmethyl bromide and by the Willgerodt reaction is described. The alpha-methyl homologue (II) was also prepared from 4-benzyloxy-3-chlorophenylacetate (VIII). The antiinflammatory, analgesic and antipyretic activities of the lysine salts of (I) (ISF 2508) and (II) (ISF 2606) were tested in comparison with alclofenac and phenylbutazone. The new ocmpounds compare favourably with the standards; in particular ISF 2508 was selected for further pharmacological studies.

Analgesics↗