Search PubMed⌕ Search

Biomedical subjects

C Minetti

Publications and source records attributed to C Minetti.

At least 37 records · Page 2Linked to original sources
PubMed1998

Very-long-chain acyl-coenzyme A dehydrogenase deficiency in a child with recurrent myoglobinuria.

A 9-year-old boy had recurrent episodes of myoglobinuria and normal urinary organic acid profile. Very-long-chain acyl-coenzyme A dehydrogenase (VLCAD) deficiency was detected biochemically in cultured skin fibroblasts and confirmed by Western blot analysis. The patient had a distinctive plasma fatty-acid profile, which was present even between attacks. Early diagnosis of this disorder is important because of the apparently protective effect of an appropriate dietary regimen.

Acyl-CoA Dehydrogenase, Long-Chain↗
PubMed1998

Primary adrenal insufficiency in a child with a mitochondrial DNA deletion.

Mitochondrial disorders can affect any organ system, but certain tissues, such as skeletal muscle, heart, and brain are more susceptible to oxidative phosphorylation defects because of their high energy requirements. Endocrinological manifestations, especially diabetes mellitus, are common but they rarely dominate the clinical picture. We describe a 5-year-old girl who died of primary adrenal insufficiency with a mitochondrial disease. Biochemical studies in muscle showed decreased respiratory chain enzyme activities. We detected a novel 7.0 kb mtDNA deletion in muscle form the proband, but not in her mother's white blood cells. Our findings further enlarge the spectrum of clinical presentation associated with mitochondrial DNA deletions.

Adrenal Insufficiency↗
PubMed1998

Mutations in the caveolin-3 gene cause autosomal dominant limb-girdle muscular dystrophy.

Limb-girdle muscular dystrophy (LGMD) is a clinically and genetically heterogeneous group of myopathies, including autosomal dominant and recessive forms. To date, two autosomal dominant forms have been recognized: LGMD1A, linked to chromosome 5q, and LGMD1B, associated with cardiac defects and linked to chromosome 1q11-21. Here we describe eight patients from two different families with a new form of autosomal dominant LGMD, which we propose to call LGMD1C, associated with a severe deficiency of caveolin-3 in muscle fibres. Caveolin-3 (or M-caveolin) is the muscle-specific form of the caveolin protein family, which also includes caveolin-1 and -2. Caveolins are the principal protein components of caveolae (50-100 nm invaginations found in most cell types) which represent appendages or sub-compartments of plasma membranes. We localized the human caveolin-3 gene (CAV3) to chromosome 3p25 and identified two mutations in the gene: a missense mutation in the membrane-spanning region and a micro-deletion in the scaffolding domain. These mutations may interfere with caveolin-3 oligomerization and disrupt caveolae formation at the muscle cell plasma membrane.

Adolescent↗
PubMed1998

Combined defects of muscle phosphofructokinase and AMP deaminase in a child with myoglobinuria.

A 14-year-old boy with exercise-related myalgia and cramps had several episodes of myoglobinuria since early childhood. An episode at 2 years of age caused acute renal failure. Histochemical and biochemical analysis of muscle showed a combined defect of phosphofructokinase (PFK) and adenosine monophosphate (AMP) deaminase. DNA analysis showed that the patient was homozygous for a G-to-C substitution at codon 39 of the PFK gene (previously described in an Italian patient) and for the common mutation found in AMP deaminase deficiency.

AMP Deaminase↗
PubMed1998

Apoptotic myonuclei in human Duchenne muscular dystrophy.

The current view that apoptosis precedes necrosis in death of dystrophin-deficient muscle fibers of the mdx mouse has been well substantiated. Moreover, apoptotic myonuclei have been reported to increase in dystrophin-deficient mice 2 days after spontaneous exercise. To investigate the role of apoptosis in human muscular dystrophy, muscles from 11 patients of different ages with Duchenne muscular dystrophy were analyzed for apoptosis. The amount of apoptosis was assessed by terminal deoxynucleotidyl transferase assay, and the expression of bcl-2 and bax was examined by immunohistochemistry. Although very rare in normal muscles (less than 0.1%), apoptotic nuclei were detected in dystrophic muscles, particularly at the interstitial level. Nevertheless, few dystrophin-deficient myofibers with centrally located nuclei showed a positive reaction for DNA fragmentation. A mosaic pattern of bcl-2/bax-positive myofibers characterized dystrophic muscles, thus the relative proportion of pro- and antiapoptotic proteins differs among muscle fibers in correlation with the presence of apoptotic myonuclei. In the interstitium, apoptotic cells were identified as macrophages and activated satellite cells. This is the first study to show an apoptotic process in adult muscle fibers of patients with Duchenne muscular dystrophy, thereby shedding new light on muscle damage and its progression in dystrophinopathies.

Apoptosis↗
PubMed1997

[Acute iatrogenic myopathy during treatment of status asthmaticus. Our experience and review of the literature].

CASE REPORT: A young man was admitted to the ICU for acute asthmatic respiratory failure. He was sedated with propofol, curarized with pancuronium and put on mechanical ventilation for 15 day because of the persistent asthmatics crisis. Drug therapy for asthma included high-dose corticosteroids. When sedation and paralysis were stopped, the patient, that was fully conscious, showed flaccid quadriplegia. A muscular biopsy showed elective loss of the myosin thick filaments. Electrophysiologic evaluation was compatible with both neurologic or muscular pathology. The evolution of the disease was good; a drop-out performed 5 months later showed a complete motor recovery. DISCUSSION: This case report confirms that in some patients, intensive treatment of status asthmaticus may cause myopathy. Only recently this myopathy has been correlated to an interaction between steroids and neuromuscular blockers. Many experimental and clinical observations suggest a negative interaction between steroids and non-depolarizing curare derivatives. In the case reported here, diagnosis was based on electrophysiologic examination and above all on muscular biopsy. CONCLUSION: The occurrence of an acute toxic myopathy should always be taken into account, considering the high number of patients admitted with respiratory failure requiring steroid treatment and curare administrative for mechanical ventilation. It therefore seems reasonable to reduce steroid therapy as soon as possible with a periodic suspension of curare administration. Curare usage should be critically evaluated. Some basic examination such as serum CPK monitoring should allow early detection of muscular damage.

Adult↗
PubMed1996

Severe dystrophinopathy in a patient with congenital hypotonia.

We studied a 2-year-old child with congenital hypotonia and proximal muscle weakness. There was no family history of neuromuscular disease. The child also had hypospadia. The central nervous system was apparently not involved. Muscle biopsy showed a dystrophic pattern and dystrophin was absent as shown by immunofluorescence and by Western blot. Vinculin and spectrin were also reduced, while merosin was normal in muscle fibers. This observation suggests that congenital hypotonia may be associated with a severe form of dystrophinopathy.

Abnormalities, Multiple↗
PubMed1996

Disruption of muscle basal lamina in congenital muscular dystrophy with merosin deficiency.

We studied three new cases of congenital muscular dystrophy (CMD) with homogeneous clinical and laboratory features, represented by congenital muscle hypotonia and weakness, early contractures, elevated serum CK, and dystrophic pattern at muscle biopsy, without clinical impairment of CNS. Merosin, the laminin isoform that contains the alpha 2 heavy chain, was absent in muscle fibers of all the patients by immunohistochemistry and by immunoblot. By electron microscopy, we found a severe disruption of muscle fiber basal lamina, but not of blood vessel basal lamina, which contains the laminin alpha 1 heavy chain isoform. This disruption may play a key role in the degeneration of muscle fibers and in the abnormal proliferation of connective tissue seen in CMD.

Basement Membrane↗
PubMed1995

[Early myoclonic encephalopathy and spinal muscular atrophy type I].

The authors describe the case of a floppy baby with the typical features of early myoclonic encephalopathy, represented by erratic and partial myoclonus of early onset and electroencephalographical suppression-burst pattern. Muscle biopsy made it possible to recognize an important neurogenic pattern, suggesting a severe form of spinal muscular atrophy. The association of these two disorders has never been reported.

Brain↗
PubMed1994

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE): clinical, biochemical, and genetic features of an autosomal recessive mitochondrial disorder.

We studied the clinical, biochemical, and genetic features of eight patients with the autosomal recessive mitochondrial syndrome mitochondrial neurogastrointestinal encephalomyopathy (MNGIE). MNGIE is clinically characterized by ophthalmoparesis, peripheral neuropathy, leukoencephalopathy, gastrointestinal symptoms (recurrent nausea, vomiting, or diarrhea) with intestinal dysmotility, and histologically abnormal mitochondria in muscle. Brain MRI scans were consistent with leukodystrophy in seven patients examined. Nerve conduction and EMG studies were compatible with a sensorimotor neuropathy; quantitative EMG of two patients suggested a myogenic process. Muscle mitochondrial enzyme analysis revealed a partial defect of cytochrome c oxidase activity in five patients; three had additional respiratory chain enzyme defects. Two patients had isolated complex I defects, and one had normal respiratory chain function. Southern blot analysis revealed multiple deletions of mitochondrial DNA in four of eight patients.

Adolescent↗
PubMed1994

Abnormalities in the expression of beta-spectrin in Duchenne muscular dystrophy.

We studied beta-spectrin using an immunologic probe in muscle samples from patients with Duchenne muscular dystrophy (DMD), Becker muscular dystrophy (BMD), other disease controls, and normal controls. By immunohistochemistry in DMD samples, beta-spectrin showed reduced or interrupted staining of the entire cell surface or only patches of bright staining at the cell periphery. There were also alterations of beta-spectrin immunostain in fibers that were not degenerating or regenerating. By immunoblotting, the amount of beta-spectrin in muscle was reduced and varied from 52% to 78% of the normal controls. We found normal values of beta-spectrin in BMD and disease controls. These observations indicate that the expression of beta-spectrin in DMD is abnormal and that beta-spectrin immunolabeling is not a good marker for monitoring membrane integrity in DMD muscle.

Adolescent↗
PubMed1994

[Muscle phosphorylase deficiency in childhood. A case report].

Myophosphorylase deficiency or McArdle's disease is rarely recognized in childhood. The onset is generally in adolescence or in adult age with exercise intolerance, muscle cramps and myoglobinuria. Two siblings of 6 and 2 years of age are described. The first patient showed early fatigue and both had elevated CK levels. Morphological and biochemical studies of muscle biopsies revealed a defect of myophosphorylase.

Child↗
PubMed1993

Dystrophinopathy in two young boys with exercise-induced cramps and myoglobinuria.

Two young boys were referred for evaluation of metabolic myopathy because of elevated serum levels of creatine kinase, cramps and pigmenturia. Immunohistochemical studies of dystrophin in muscle biopsies showed reduced intensity of the stain with a patchy and discontinuous pattern in most fibers. In both patients dystrophin was undetectable by immunoblotting. DNA analysis of the dystrophin gene was not informative in one patient; in the other it revealed an in-frame deletion comprising exons 3-6. These observations suggest that the two patients are affected with an unusual phenotype of Becker muscular dystrophy. Dystrophin analysis should be included in the evaluation of patients with childhood-onset of recurrent myoglobinuria.

Child↗
PubMed1992

Dystrophin at the plasma membrane of human muscle fibers shows a costameric localization.

We studied the distribution of dystrophin at the sarcolemma of normal human muscle fibers using high resolution immunofluorescence and confocal laser scanning optical microscopy (CLSOM). We found that the dystrophin lattice is organized at the muscle plasma membrane in an array of thick bands interconnected by a finer network. The bands encircle the muscle fiber perpendicular to the long axis of the fiber and they matched the sites of attachment of the sarcomeres to the plasma membrane. Dystrophin co-localized with vinculin, and dystrophin and vinculin co-localized with alpha-actinin at the region of the I-band. Dystrophin may be one of the proteins involved in the linkage of the sarcomeres to the extracellular matrix.

Actinin↗