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Biomedical subjects

C Scoppetta

Publications and source records attributed to C Scoppetta.

At least 19 recordsLinked to original sources

Anomalous levels of Cl- transporters in the hippocampal subiculum from temporal lobe epilepsy patients make GABA excitatory.

The mRNA levels of NKCC1, an inwardly directed Na(+), K(+)-2Cl(-) cotransporter that facilitates the accumulation of intracellular Cl(-), and of KCC2, an outwardly directed K(+)-Cl(-) cotransporter that extrudes Cl(-), were studied in surgically resected brain specimens from drug-resistant temporal lobe (TL) epilepsy (TLE) patients. Quantitative RT-PCR analyses of the mRNAs extracted from the human TLE-associated brain regions revealed an up-regulation of NKCC1 mRNA and a down-regulation of KCC2 mRNA in the hippocampal subiculum, compared with the hippocampus proper or the TL neocortex, suggesting an abnormal transcription of Cl(-) transporters in the TLE subiculum. In parallel experiments, cell membranes isolated from the same TLE-associated brain regions were injected into Xenopus oocytes that rapidly incorporated human GABA(A) receptors into their surface membrane. The GABA currents elicited in oocytes injected with membranes from the subiculum had a more depolarized reversal potential (E(GABA)) compared with the hippocampus proper or the neocortex. The NKCC1 blocker bumetanide or a temperature decrease of 10 degrees C shifted the GABA-current E(GABA) more negative in oocytes injected with membranes from TLE hippocampal subiculum, matching the E(GABA) of TL neocortex-injected oocytes. We conclude that the anomalous expression of both Cl(-) transporters, NKCC1 and KCC2 [corrected] in TLE hippocampal subiculum probably causes altered Cl(-) transport in the "epileptic" neurons, as revealed in the microtransplanted Xenopus oocytes, and renders GABA aberrantly "exciting," a feature that may contribute to the precipitation of epileptic seizures.

Animals↗

Erythropoietin: a new tool for muscle disorders?

The main action of erythropoietin (EPO) is to regulate the production of red cells. However both experimental evidence and clinical experience suggest that erythropoietin has a positive effect on skeletal and cardiac muscle. Mice lacking EPO or its receptors suffer from hearth hypoplasia and have a reduced number of proliferating cardiac myocytes. EPO receptors are expressed on mouse primary satellite cells and in cultured myoblasts, and their stimulation appears to enhance proliferation and reduce the differentiation of both cell types. Moreover EPO is capable of promoting angiogenesis in muscle cells, which provides an additional route to increase oxygen supply to active muscles. In men, the effects of EPO on muscle cells are suggested by the illegal use of EPO by agonistic and amateur athletes to enhance their performances. In some athletes EPO improved their long-duration muscular performances much more than expected on the basis of the increment of the blood hemoglobin alone. Our proposal is to investigate the effect of EPO treatment in various animal models of muscular dystrophies (MD), which are common hereditary primary muscle disorders characterized by muscle damage and wasting, to date without any effective treatment. The ability of EPO to induce the proliferation of satellite cells in the presence of differentiating conditions, typical of the damaged muscle, may represent a tool to expand the cellular population competent for muscle repair. This would lengthen the period when muscles can be efficiently repaired. In the presence of positive results, the possibility could be considered of selecting some of the human forms of MD and treating the patients with EPO.

Animals↗

Facioscapulohumeral muscular dystrophy presenting isolated monomelic lower limb atrophy. Report of two patients with and without 4q35 rearrangement.

Facioscapulohumeral muscular dystrophy has a distinctive regional distribution but variable clinical expression and may be markedly asymmetrical. We report two patients presenting weakness and wasting confined to a single lower limb. Creatine kinase was slightly increased, electromyogram and muscle biopsy were myopathic. Muscle computed tomography showed normal shoulder, mid-arm, pelvic and mid-thigh scans but involvement of calf muscles. In both cases, weakness of facial and periscapular muscles was found in other family members unaware of the disease. Molecular analysis showed 4q35 deletion in one family. These cases broaden the presentation of facioscapulohumeral muscular dystrophy to include isolated monomelic atrophy of lower limb with calf muscle involvement.

Adult↗

Autosomal dominant distal myopathy: further evidence of a chromosome 14 locus.

In 1995 Laing et al. (Am J Hum Genet 56(1995)422) described a single family with nine members affected by an autosomal dominant infantile onset distal myopathy. This family generated a LOD score of 2.6 for a locus on chromosome 14. We describe two families with an infantile onset distal myopathy: a new family with four affected members and the family previously described by Scoppetta et al. (Acta Neurol Scand 92(1955)122) in both of which haplotype segregation was compatible with linkage to the same chromosome 14 locus, generating LOD scores of 0.9 at a penetrance of 100% for the markers D14S283 and D14S64 (theta=0) in both families. The loci for autosomal recessive hereditary inclusion body myopathy and Nonaka myopathy on chromosome 9 and for autosomal dominant distal myopathy of Markesberry-Griggs and Udd on chromosome 2q31-33 were excluded by linkage analysis. The disease followed a uniform course with selective wasting of the anterior tibial muscles, starting in infancy and recognizable by a characteristic clinical sign of the 'hanging big toe'. This was followed by slow progression, with involvement of the finger and wrist extensor muscles in the third decade and proximal limb muscles in the fourth decade. Interestingly, we also found evidence of an accompanying mild peripheral neuropathy in the oldest individual with hypomyelination of numerous large myelinated fibres. In addition, this patient's muscle biopsy also showed autophagic vacuoles and numerous intranuclear tubulo-filamentous inclusions of 15-20 nm diameter. Given that all three families with infantile onset distal myopathy are compatible with linkage to the same locus on chromosome 14, this study supports evidence for, and enlarges the clinical and neuropathological spectrum of the distal myopathy on chromosome 14.

Adolescent↗

Low dosage clozapine effects on L-dopa induced dyskinesias in parkinsonian patients.

OBJECTIVES: The aim of this study was to investigate the clinical efficacy of clozapine, an atypical neuroleptic, on L-dopa induced dyskinesias of Parkinson's disease. MATERIAL AND METHODS: In an open study, a group of 10 PD patients was treated with low dosage clozapine (mean 30 mg/day) for a 4-month period and L-dopa dyskinesias were evaluated in basal conditions and during clozapine treatment after the usual morning dose of clozapine. We utilized the AIMS for evaluation of dyskinesias and UPDRS for the assessment of motor performances. RESULTS: Clozapine produced a significant (P<0.05) reduction of dyskinesias 1 week after the therapy onset. This effect was more pronounced at the end of the 2nd week and remained stable through the following months. We did not observe significant variations of motor performances. CONCLUSION: A low dose of clozapine appears to be beneficial for patients with L-dopa induced dyskinesias that do not respond to other drugs and therapeutic measures.

Aged↗

Autosomal recessive distal muscular dystrophy.

The "distal myopathies" include autosomal dominant, autosomal recessive, and sporadic disorders. Two of the recessive disorders are considered to be definitive entities: Miyoshi's myopathy, which has an early adult onset and first involves the calf muscles, and distal myopathy with rimmed vacuoles. We here describe the cases of two sisters and compare them with previously reported cases. The disorder in our patients is characterised by: a) autosomal recessive inheritance; b) onset in early adult life; c) initial involvement of the tibialis anterior and peroneal muscles; d) subsequent involvement of the calf muscles spreading to the proximal muscles of the legs and, later, the arms; e) a moderately disabling evolution over a period of 10-12 years; f) marked and stably high serum levels of CK and other enzymes; g) EMG evidence of myopathic damage, with fibrillation at rest; and h) a histological picture of dystrophic myopathy, with atrophy of mainly type 2 fibres. We think that this syndrome is different from the two forms of autosomal recessive distal myopathy mentioned above.

Adolescent↗

Infantile autosomal dominant distal myopathy.

INTRODUCTION: Distal myopathies are currently regarded as a non-homogeneous group of disorders including different autosomal dominant, recessive and sporadic forms. MATERIAL AND METHODS: The cases of a mother and her son and daughter are described and compared to previously reported cases from 4 families. Despite minor differences, the clinical picture is remarkably homogeneous, both within the same family and among different families. CONCLUSION: A distinct clinical form can be identified including: a) autosomal dominant inheritance; b) onset in infancy or childhood with peroneal muscles weakness; c) not disabling evolution in spite of possible late involvement of muscles others than tibio-peroneal; d) usually normal serum CK and other muscle enzymes; e) EMG evidence of primary myogenic damage; f) morphological findings of non-specific myopathy. Because of the benign evolution and the absence of true dystrophic changes in most biopsies we suggest the term infantile autosomal dominant distal myopathy should be preferred to infantile autosomal dominant distal muscular dystrophy.

Adolescent↗

The treatment of patients with myasthenia gravis.

Although there is general agreement among experienced physicians on the usefulness of different treatments for myasthenia gravis (MG), so many variations are possible that in practice, similar patients treated by different physicians rarely are treated the same. Because of these divergent opinions one may read papers in reputable journals that present and propose extremely variable programs for treating MG. Scientific controversies, although stimulating, often result in confusion, especially for less experienced physicians seeking treatment guidelines for their patients. This article offers the authors' opinions on the benefits and limitations of the therapeutic modalities used in MG and their proposals of therapeutic plans for specific situations.

Adrenal Cortex Hormones↗

Repetitive stimulation in myasthenia gravis: decrementing response revealed by anticholinesterase drugs.

In myasthenia gravis (MG) a typical decrementing response is frequently revealed with repetitive stimulation (RS) in clinically unaffected muscles. However, RS is unlikely to give normal results in weak muscles. In two of our patients we found a normal response in clinically affected muscles. However, a decrementing response surprisingly appeared after the administration of anticholinesterase drugs. A possible explanation for this apparently paradoxical effect is as follows: some junctions are already blocked at rest, whereas others function normally both at rest and during RS. As a consequence, the initial compound muscle action potential (CMAP) is reduced in amplitude and shows no further decrement on RS. Anticholinesterase drugs reverse some blocks, therefore causing the CMAP increase in amplitude. However, these labile junctions are more prone than normal to synaptic fatigue, so a decrementing response is produced on RS. This behavior, though not frequently encountered, can account for some negative results of RS in MG.

Action Potentials↗

[Surgical treatment of blepharoptosis in patients with mitochondrial myopathies. Apropos of 4 cases].

The authors briefly describe the commonest forms of mitochondrial myopathies particularly those associated with disorders of ocular motility. They report their series of four patients suffering from ptosis of the eyelid caused by mitochondrial myopathies. The ptosis was corrected surgically in all cases by means of Müller's muscle adaptation technique. The authors discuss their results and the indication for this technique.

Adult↗

Specificity of calcium channel autoantibodies in Lambert-Eaton myasthenic syndrome.

Autoantibodies that interfere with neurotransmitter release by affecting the function of voltage-operated calcium channels (VOCCs) have been found in patients with Lambert-Eaton myasthenic syndrome (LES). To find out the nature of the antigen to which these autoantibodies bind, tests were done with omega-conotoxin, which blocks some types of VOCCs. LES antibodies were able to immunoprecipitate VOCCs prepared from the human neuronal cell line IMR32 which were pre-labelled with the specific VOCC ligand omega-conotoxin. LES autoantibodies are also able to specifically down-regulate the expression of VOCCs in IMR32 cells. A new radioimmunoassay for the quantitative detection of LES antibodies was developed and found to be of value in distinguishing LES patients from patients with myasthenia gravis and some other neurological disorders.

Autoantibodies↗

Neonatal myasthenia gravis: clinical and immunological study of seven mothers and their newborn infants.

We studied 7 mothers with myasthenia gravis (MG) and their infants. We confirmed that the development of neonatal MG was not related to the serum titer of maternal anti-acetylcholine receptor antibody (anti-AChR ab). To investigate the possibility that specific immunization of the newborn infant had occurred, serial serum determinations of total and 'specific' anti-AChR IgG and IgM were performed. We found that: the decay in total IgG was within the normal range in all the babies; there was a shorter half-life of 'specific' IgG, compared to total IgG, in 3 of the cases, 2 of which did have neonatal MG; no difference was found between the decay of anti-AChR ab in the babies who had neonatal MG and those who did not; there was no anti-AChR IgM-associated activity. Our data suggest that neonatal MG is due to maternal anti-AChR abs and that affected infants do not produce specific antibodies.

Autoantibodies↗

Estrogen binding sites in peripheral blood mononuclear cells and thymocytes from 2 myasthenia gravis patients.

In the present investigation the estrogen binding capacity of peripheral blood mononuclear cells (PBMC) and thymocytes from 2 young female Myasthenia Gravis (MG) patients has been studied. We found high levels of estrogen binding sites in both pre-thymectomy PBMC and lymphoid cells from the hyperplastic thymuses of the MG patients. A sucrose density gradient analysis revealed that the estrogen was binding to macromolecular species similar to those characterized in cytosols from classical estrogen target organs. A post-thymectomy time-dependent decrease of the estrogen binding capacity was also observed in PBMC, reaching levels similar to that of sex- and age-matched controls.

Adolescent↗