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Biomedical subjects

F Micheli

Publications and source records attributed to F Micheli.

At least 37 records · Page 2Linked to original sources
PubMed1999

Cycloalkyl indole-2-carboxylates as useful tools for mapping the "north-eastern" region of the glycine binding site associated with the NMDA receptor.

A novel series of indole-2-carboxylate analogues of GV 150526 (1) in which the terminal phenyl ring belonging to the side chain present in the position C-3 has been replaced with a bridged cycloalkyl group was synthesized and evaluated for its pharmacological profile. Modelling studies on this class of novel glycine antagonist allowed us to identify an asymmetric lipophilic pocket present in the "North-Eastern" region of the pharmacophoric model of the glycine binding site associated to the NMDA receptor. Among the derivatives prepared, 3-[2-(1-adamantylaminocarbonyl)ethenyl]-4,6-dichloroindole-2 -carboxylic acid 6b and 3-[2-(norbornylaminocarbonyl)ethenyl]-4,6-dichloroindole-2-c arboxylic acid 6l were found to be antagonists acting at the strychnine-insensitive glycine binding site, showing nanomolar affinity for the glycine binding site (Ki = 63 and 19 nM, respectively), coupled with high glutamate receptor selectivity (IC50 > 10(-5) M at the NMDA, AMPA, KA binding sites) and high in vivo potency after systemic administration by inhibition of convulsion induced by NMDA in mice.

Amantadine↗
PubMed1999

Substituted indole-2-carboxylates as potent antagonists of the glycine binding site associated with the NMDA receptor.

A novel series of indole-2-carboxylate analogues of GV150526 (1) in which the propenoic double bond was substituted with different "probes" or replaced by a isosteric cyclopropyl moiety were synthesized and evaluated for their affinity profile in order to obtain further information on the pharmacophoric model of the glycine binding site associated to the NMDA receptor.

Animals↗
PubMed1999

Beneficial effects of diphenhydramine in dystonia.

The objective of this paper was to evaluate the efficacy of diphenhydramine hydrochloride (DPH) in dystonic patients. In 1995, Truong et al reported encouraging results in five patients with idiopathic torsion dystonia (ITD) treated with DPH, an H1 antagonist with sedative and anticholinergic properties. Five patients with generalized ITD, one with secondary generalized dystonia and one with idiopathic segmental dystonia were included in the prospective study. Initially the response to intravenous administration of DPH versus placebo in two sessions a week apart was evaluated. Two weeks later all patients started oral DPH in increasing doses (range 100-300 mg, mean 164 mg). The degree of dystonia was determined by a modified University of Columbia Scale evaluating the baseline score, after placebo and DPH I.V. administration then at one and six months after starting oral treatment. The results were analyzed by Friedman's test for repeated measurements. On comparing scores for baseline severity, I.V. placebo and I.V. DPH presented a highly significant correlation (12.09; p = 0.00) as well as comparing baseline score with oral DPH at one and 6 months, treatment (12.78; p = 0.00). Functional score results were 9.5 p = 0.01 and 8.4 p = 0.02 at one and 6 months respectively. The most common side effects were somnolence and dizziness. It can be concluded that DPH proved effective in our patients with mild to moderate adverse effects not requiring drug withdrawal in any case. However, I.V. challenge was unable to predict the long-term response to oral medication perhaps due to the limited number of cases.

Adolescent↗
PubMed1998

Characterization of the pectin methylesterase-like gene AtPME3: a new member of a gene family comprising at least 12 genes in Arabidopsis thaliana.

Pectin demethylesterification appears to be catalysed by a number of pectin methylesterase (PME) isoenzymes in higher plant species. In order to better define the biological role of these isoenzymes in plant cell growth and differentiation, we undertook molecular studies on the PME-encoding genes in Arabidopsis thaliana. In this paper, we report the characterization of AtPME3, a new PME-related gene of 4kb in length that we have mapped on Chromosome III. AtPME3 encodes a putative mature PME-related isoenzyme of 34kDa with a basic isoelectric point. Since the extent of the gene family encoding PME in higher plant species is still unknown, we resorted to the use of degenerate primers designed from several well-known consensus regions to identify new PME-related genes in the genome of Arabidopsis. Our results, in combination with several known expressed sequences tags (ESTs), indicate that the Arabidopsis genome contains at least 12 PME-related genes. Consequently, a method of systematic gene expression analysis has been applied in order to discern the expression pattern of these 12 genes throughout the plant at the floral stage. Whereas most of these genes appeared to be more or less ubiquitously expressed throughout the plant, several genes are distinguishable by their strikingly specific expression in certain organs. The present data bring a new insight into the role of specific PME-related genes in flower and root development.

Amino Acid Sequence↗
PubMed1997

Substituted indole-2-carboxylates as in vivo potent antagonists acting as the strychnine-insensitive glycine binding site.

A series of indole-2-carboxylates bearing suitable chains at the C-3 position of the indole nucleus was synthesized and evaluated in terms of in vitro affinity using [3H]glycine binding assay and in vivo potency by inhibition of convulsions induced by N-methyl-D-aspartate (NMDA) in mice. 3-[2-[(Phenylamino)carbonyl]ethenyl]-4,6-dichloroindole-2-carboxyl ic acid (8) was an antagonist at the strychnine-insensitive glycine binding site (noncompetitive inhibition of the binding of [3H]TCP, pA2 = 8.1) displaying nanomolar affinity for the glycine binding site (pKi = 8.5), coupled with high glutamate receptor selectivity (> 1000-fold relative to the affinity at the NMDA, AMPA, and kainate binding sites). This indole derivative inhibited convulsions induced by NMDA in mice, when administered by both iv and po routes (ED50 = 0.06 and 6 mg/kg, respectively). The effect of the substituents on the terminal phenyl ring of the C-3 side chain was investigated. QSAR analysis suggested that the pKi value decreases with lipophilicity and steric bulk of substituents and increases with the electron donor resonance effect of the groups present in the para position of the terminal phenyl ring. According to these results the terminal phenyl ring of the C-3 side chain should lie in a nonhydrophobic pocket of limited size, refining the proposed pharmacophore model of the glycine binding site associated with the NMDA receptor.

Animals↗
PubMed1997

Effects of experience on crab foraging in a mobile and a sedentary species

The effects of experience on prey and prey-patch choice were compared between two species of marine predatory crabs. The blue crab, Callinectes sapidus Rathbun, is highly mobile and forages in a variety of estuarine and lagoonal habitats. The Atlantic mud crab, Panopeus herbstii H. Milne-Edwards, is smaller and less mobile and is found mostly in oyster reefs and on shelly bottoms. In the laboratory, crabs were offered a choice between two prey types (juvenile hard clams, Mercenaria mercenaria Linne, and juvenile oysters, Crassostrea virginica Gmelin) following a preliminary phase in which crabs were trained to feed on clams only, oysters only or a mixture of the two prey types. In field enclosures, crabs were offered a choice between patches of juvenile hard clams located in an inter-tidal salt marsh and in an adjacent unvegetated inter-tidal flat after they were trained to feed in either one of the two habitat types. Both in the laboratory prey-choice and the field prey-patch choice experiments, blue crabs modified their foraging behaviour depending on previous experience. The effect of experience on their foraging behaviour did not diminish after 24 hours. Experience had no significant effects on the foraging behaviour of mud crabs. Differences in the ecological contexts (e.g. in the variability of prey quality and availability) in which the two species forage may explain the greater effect of experience on the blue crab foraging behaviour, although alternative explanations cannot be ruled out.

Journal Article↗
PubMed1996

Familial bulbospinal neuronopathy with optic atrophy: a distinct entity.

A 61 year old woman and her 58 year old brother presented with the clinical picture of late onset progressive bulbar and spinal muscular atrophy with family history of involvement in successive generations. The sister also had optic neuropathy and the brother developed diabetes mellitus and sex hormone abnormalities. Neurophysiological and histopathological studies showed a pattern of motor and sensory neuronopathy. There was no abnormal expansion of CAG repeats in the androgen receptor gene. This family seems to have a previously unrecognised entity with the bulbospinal neuronopathy phenotype.

Electromyography↗
PubMed1994

Familial hemifacial spasm.

Two brothers developed hemifacial spasm at 63 and 70 years of age. Spasms occurred on the left and right sides of the face, respectively. Computed tomography scan and magnetic resonance imaging failed to show any abnormality. In addition, a third sibling reported a history of a peripheral facial palsy, which remitted spontaneously without sequelae. This is the fourth description of familial hemifacial spasms. This family is unique in that hemifacial spasm presented on different sides in the two brothers, and involvement was limited to one generation. Age at onset was later than for other familial cases and similar to sporadic cases.

Aged↗
PubMed1994

[Neurologic complications by cocaine abuse].

Argentina is facing an increase in cocaine use by adolescents and young adults from every socioeconomic background. It is calculated that up to 10% of all cocaine passing through this country is locally sold and consumed. Nevertheless, local information describing common cocaine-related neurological events is scarce. From August 1988 to March 1993, 13 patients were evaluated with neurological disease associated with cocaine abuse. Among these 13 patients (Table 1), the mean age was 29; 70% were men. Patients most commonly used the nasal route (snorting). Concomitant abuse of other intoxicants, especially alcohol, was frequent (85%). The major neurological complications included one or more seizures (n = 7), ischemic stroke (n = 2) (Fig. 1-2), hemorrhagic stroke (n = 2) associated with arteriovenous malformation (Fig. 3a-b), memory disturbances (n = 1) and paroxysmal dystonia (n = 1). Psychiatric complaints were present in all patients. Mortality was not observed. There was no correlation between the appearance of complications and the amount of cocaine used, or prior experience with this drug. Only one of the 7 patients with seizures had a previous history of seizures. All had generalized tonic-clonic seizures, and one had concomitant absence episodes. Cocaine modulates central neurotransmitters and has direct cerebrovascular effects. The neurological complications appear to be related to cocaine hyperadrenergic effects, striatal dopaminergic receptor hypersensitivity and perhaps vasculitis. Structural changes in the brain of long-term cocaine abusers could explain the persistence of neurologic symptoms after drug withdrawl.

Adolescent↗
PubMed1994

L-dopa malabsorption in a parkinsonian patient with Strongyloides stercoralis duodenitis.

We report a parkinsonian patient initially responding to L-dopa who developed a severe loss of drug efficacy due to Strongyloides stercoralis duodenitis. The patient was put on mebendazole and metronidazole, and the parasitosis abated, allowing L-dopa reduction by 33%. Our patient illustrates the advisability of searching for Strongyloides stercoralis when L-dopa malabsorption is suspected in Parkinson's disease.

Aged↗