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Biomedical subjects

C Angelini

Publications and source records attributed to C Angelini.

At least 73 records · Page 4Linked to original sources
PubMed1999

Evidence for the presence of a mammalian-like cholinesterase in Paramecium primaurelia (Protista, Ciliophora) developmental cycle.

By histochemical and immunohistochemical methods, the presence of cholinergic-like molecules has previously been demonstrated in Paramecium primaurelia, and their functional role in mating-cell pairing was suggested. In this work, both true acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activities were electrophoretically investigated, and the presence of molecules immunologically related to BuChE was checked by immunoblotting. The AChE activity, shown in the membrane protein fraction of mating-competent cells and in the cytoplasmic fraction of immature cells, is due to a 260-kDa molecular form, similar to the membrane-bound tetrameric form present in human erythrocytes. This AChE activity does not appear in either the cytoplasmic fraction of mating-competent cells or in the membrane protein fraction of immature cells. No evidence was found for the presence or the activity of BuChE-like molecules. The role of AChE in P. primaurelia developmental cycle is discussed.

Acetylcholinesterase↗
PubMed1999

The clinical spectrum of sarcoglycanopathies.

A group of 204 muscular dystrophy patients were screened for immunohistochemical and biochemical alpha-sarcoglycan defect and their DNA was analyzed for pathogenetic mutation in the four sarcoglycan genes. We identified 21 patients with alpha-, beta-, or gamma-sarcoglycan gene mutations. Patients with alpha-sarcoglycan gene mutations were clinically heterogeneous and showed either a rapid progressive or a late-onset slow course. In the slowly evolving group, a residual alpha-sarcoglycan protein was present, and its level correlated with a milder disease course and significant later inability to stand up from the floor (p < 0.00005). Most patients with beta- and gamma-sarcoglycan gene mutations presented a severe clinical course. There is a considerably different pattern of muscle involvement and disease course in these disorders, compared with dystrophinopathies.

Adolescent↗
PubMed1999

Heart involvement in muscular dystrophies due to sarcoglycan gene mutations.

Mutations in the sarcoglycan genes cause autosomal-recessive muscular dystrophies. Because sarcoglycan genes and their protein products are highly expressed both in skeletal and cardiac muscle, patients with these mutations might be expected to be at risk to develop dilated cardiomyopathy. We therefore studied 13 patients with alpha-, beta-, gamma-sarcoglycan gene mutations by thorough cardiological assessment. Electrocardiographic or echocardiographic abnormalities were observed in about 30% of cases showing a severe course of muscular dystrophy. No correlation was found between the presence of cardiac abnormalities and the type of mutation or sarcoglycan gene involved. The cardiac involvement was never severe, but it may be detected in early stages of the muscle disease. The absence of overt cardiac dysfunction may be due to lower sarcoglycan protein expression in cardiac than skeletal muscle or to less sarcolemmal instability at the myocardial level, possibly related to the different distribution of forces generated by contraction of the myocardium with respect to proximal limb-girdle muscles.

Adolescent↗
PubMed1999

Could utrophin rescue the myocardium of patients with dystrophin gene mutations?

The spontaneous up-regulation of utrophin, observed in dystrophin-deficient skeletal muscle fibers, may decrease the susceptibility of such fibers to necrosis. It has been reported that the utrophin-rescued double-mutant mdx mouse always develops a lethal cardiomyopathy. We report two patients with severe dilated cardiomyopathy due to dystrophin gene mutations: the first was a manifesting Duchenne muscular dystrophy carrier and the second a patient affected with moderate Becker muscular dystrophy. We studied their explanted heart specimen and/or endoImyocardial biopsies by immunohistochemistry and Western blot for both dystrophin and utrophin. Utrophin was found to be over-expressed in these specimens. Our results suggest that in these patients the up-regulation of utrophin in dystrophin-deficient cardiomyocytes was unable to prevent the development of life-threatening myocardial dysfunction. These findings seem to dampen the enthusiasm raised by the prospect of DMD treatment by utrophin rescue in skeletal muscle fibers, as the myocardium would still remain severely affected.

Adult↗
PubMed1999

Clinical and neuroimaging study of central nervous system in congenital myotonic dystrophy.

We present the clinical and neuroimaging findings of five patients (four males, one female; mean age 12 years) affected by congenital myotonic dystrophy and the correlation with their molecular genetic analysis. At birth all five presented severe muscular weakness and hypotonia, associated with feeding difficulties and respiratory distress. In the same patients, congenital clubfoot or more generalized arthrogryposis was also evident. Lymphocyte DNA was characterized in each by a CTG repeat longer than 1300 in the region of the myotonic dystrophy gene in chromosome 19. The patients' neurological condition was evaluated by clinical examination, intelligence tests, electroencephalography, and brain magnetic resonance imaging. All five suffered from some impairment of intellectual function (IQ ranged from 52 to 79). In three a longitudinal evaluation of the cognitive deficit detected no deterioration. In all patients magnetic resonance imaging showed some degree of ventricular dilatation, loosely correlated to the cognitive impairment; in three there was hypoplasia of the corpus callosum and in two mild abnormalities of supratentorial white matter. The relationship between the size of the CTG repeat expansion found in lymphocyte DNA and the cerebral abnormalities appeared inconsistent in this unusual myoencephalopathy of the newborn.

Adolescent↗
PubMed1999

Infantile lipid storage myopathy with nocturnal hypoventilation shows abnormal low-affinity muscle carnitine uptake in vitro.

An infant with respiratory insufficiency, cardiomyopathy, lipid storage myopathy and low muscle carnitine was diagnosed as having 'Ondine's curse' because of recurrent nocturnal hypoventilation. Carnitine uptake was studied in 20-day-old cultured muscle, where two distinct saturable transport components are recognized: the high- and low-affinity-uptake. Experimental evidence suggests that low-affinity-uptake is muscle-specific, operating at physiological carnitine concentration. In the patient's cultured myotubes, the low-affinity-uptake K(m) was 260% of controls (P < 0.01), whereas kinetic parameters of high-affinity uptake were normal. The high K(m) indicates an immature or altered carnitine muscle carrier, which may decrease the physiologic carnitine uptake.

Carnitine↗
PubMed1999

Reduction of the DM-associated homeo domain protein (DMAHP) mRNA in different brain areas of myotonic dystrophy patients.

Myotonic dystrophy (DM) is a multisystemic disease caused by expansion of a CTG trinucleotide repeat in the 3' untranslated region of the DMPK protein kinase gene on chromosome 19q13.3. The mechanism by which this expansion causes disease remains unknown. It has been suggested that CTG expansion not only affects the expression of the DMPK gene, but also alters the nuclear RNA metabolism and expression of neighboring genes. DMAHP, which is expressed in various human tissues, including skeletal muscle, heart and brain, is immediately distal to the 3' end of DMPK gene, in a CpG island which contains the CTG repeat. Here we report a 4- to 5-fold reduction of the expression of the DMAHP gene in different brain areas of DM patients. Our results demonstrate that [CTG]n expansion alters the brain DMAHP mRNA expression supporting a dominant-negative effect at the cellular level of DM [CTG]n mutation. The reduced brain expression of DMAHP could explain cerebral impairment in DM patients.

Brain Chemistry↗
PubMed1999

Prenatal diagnosis in a family affected with beta-sarcoglycan muscular dystrophy.

We present here the first prenatal diagnosis in beta-sarcoglycan muscular dystrophy. The consultand was an 11-week pregnant mother of a girl diagnosed at the age of 3 years with beta-sarcoglycan muscular dystrophy based on the identification of two nonsense mutations in her beta-sarcoglycan gene and on the absence of beta-sarcoglycan in her muscle biopsy. The direct search for these mutations in the chorionic villus DNA of the fetus showed that the fetus did not inherit her sister mutations and thus, was reported as unaffected. We suggest that direct gene mutation detection is more reliable than linkage or protein study in the prenatal diagnosis of sarcoglycanopathies.

Child, Preschool↗
PubMed1999

A stop-codon mutation in the human mtDNA cytochrome c oxidase I gene disrupts the functional structure of complex IV.

We have identified a novel stop-codon mutation in the mtDNA of a young woman with a multisystem mitochondrial disorder. Histochemical analysis of a muscle-biopsy sample showed virtually absent cytochrome c oxidase (COX) stain, and biochemical studies confirmed an isolated reduction of COX activity. Sequence analysis of the mitochondrial-encoded COX-subunit genes identified a heteroplasmic G-->A transition at nucleotide position 6930 in the gene for subunit I (COX I). The mutation changes a glycine codon to a stop codon, resulting in a predicted loss of the last 170 amino acids (33%) of the polypeptide. The mutation was present in the patient's muscle, myoblasts, and blood and was not detected in normal or disease controls. It was not detected in mtDNA from leukocytes of the patient's mother, sister, and four maternal aunts. We studied the genetic, biochemical, and morphological characteristics of transmitochondrial cybrid cell lines, obtained by fusing of platelets from the patient with human cells lacking endogenous mtDNA (rho0 cells). There was a direct relationship between the proportion of mutant mtDNA and the biochemical defect. We also observed that the threshold for the phenotypic expression of this mutation was lower than that reported in mutations involving tRNA genes. We suggest that the G6930A mutation causes a disruption in the assembly of the respiratory-chain complex IV.

Adult↗
PubMed1999

Riboflavin therapy. Biochemical heterogeneity in two adult lipid storage myopathies.

Two unrelated adult males, aged 36 (patient 1) and 25 (patient 2) years, presented with subacute carnitine-deficient lipid storage myopathy that was totally and partly responsive to riboflavin supplementation in the two patients, respectively. Plasma acyl-carnitine and urinary organic acid profiles indicated multiple acyl coenzyme A dehydrogenase deficiency, which was mild in patient 1 and severe in patient 2. The activities of short-chain and medium-chain acyl coenzyme A dehydrogenases in mitochondrial fractions were decreased, especially in patient 2. This was in agreement with Western blotting results. Flavin-dependent complexes I and II were studied by immunoblotting and densitometric quantification of two-dimensional electrophoresis with comparable results. Complex I was present in normal amounts in both patients, whereas complex II was decreased only in the pretherapy muscle of patient 2. Flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN) concentrations in muscle and isolated mitochondria, and the activity of mitochondrial FAD pyrophosphatase, showed that patient 1 had low levels of FAD (46%) and FMN (49%) in mitochondria, with a significant increase (P < 0.01) in mitochondrial FAD pyrophosphatase (273%) compared with controls. Patient 2 had similar low levels of FAD and FMN in both total muscle (FAD and FMN 22% of controls) and mitochondria (FAD 26%; FMN 16%) and normal activity of mitochondrial FAD pyrophosphatase. All of these biochemical parameters were either totally or partly corrected after riboflavin therapy.

Adult↗
PubMed1999

Myotonic dystrophy: tissue-specific effect of somatic CTG expansions on allele-specific DMAHP/SIX5 expression.

Myotonic dystrophy (DM), the most common inherited muscle disorder, is caused by a CTG expansion in the 3"-untranslated region of a protein kinase gene ( DMPK ). The complex and variable phenotype is most likely caused by a complex molecular pathogenesis, including deficiency of the DMPK protein, a trans -dominant misregulation of RNA homeostasis and haploinsufficiency of a neighboring homeobox gene [DM locus-associated homeodomain protein (DMAHP )]. Here, we study the allele-specific transcriptional activity of the DMAHP/SIX5 gene in DM patient tissues. Using a quantitative fluorescent RT-PCR assay, we tested allele-specific accumulation of DMAHP/SIX5 transcripts in both total and poly(A)+pools. In muscle biopsies, we found that transcript reductions of DMAHP/SIX5 alleles in cis with CTG expansions correlated with the extent of expansion. A patient with approximately 90 CTG repeats in muscle DNA (normal n < 37) showed a 20% reduction of allele-specific transcript levels, while four other DM patients with larger expansions showed 80% reductions. The effects of the CTG expansions on DMAHP transcription were tissue specific: autopsy tissues from a patient with 1500 repeats showed 80% reductions in muscle and liver; however, RNA from other tissues (lung, aorta, heart conduction tissue, cerebellum) showed 0-20% reductions. Our results suggest that the effect of the CTG repeat on the DMAHP/SIX5 promoter is variable and tissue-specific. Our data are consistent with abnormalities of DMAHP/SIX5 probably having a more prominent role in disease pathogenesis in muscle, liver and brain, but being less important in other tissues.

Adult↗
PubMed1998

Cholinergic activation of settlement in Ciona intestinalis metamorphosing larvae.

During metamorphosis, ascidian tadpoles settle on appropriate substrates, by secreting adhesive substances from the papillae. The papillae were shown by different authors to possess neural structures, probably for substrate recognition. In free-swimming tadpoles, AChE activity was localized by histochemical methods at the cell surface of the adhesive papillae, suggesting the possible presence of a cholinergic system in these structures. In vivo experiments showed that the treatment with AChCl caused dose-dependent enhancement of metamorphosis, shortening of the exploratory period of the larvae, and secretion within a few minutes of sConA-binding glycoconjugates in the tunica, beginning from the adhesive papillae.

Acetylcholine↗
PubMed1998

Homozygous alpha-sarcoglycan mutation in two siblings: one asymptomatic and one steroid-responsive mild limb-girdle muscular dystrophy patient.

We describe a couple of siblings who have a homozygous mutation in the alpha-sarcoglycan gene and present a striking clinical difference in their phenotype; the brother is asymptomatic, and the sister is affected with mild limb-girdle muscular dystrophy. Drug therapy with a new steroid (deflazacort) was done over 6 months in the mild limb-girdle patient, and we observed objective benefit in muscle strength and in functional tests. Side effects were minimal. Immunohistochemistry for alpha-sarcoglycan showed reduced intensity of reaction in the limb-girdle dystrophy patient and was similar to normal in the asymptomatic case. A reduced amount of residual alpha-sarcoglycan protein level was found in their muscle biopsies. Unknown epigenetic or environmental factors may have an important role in determining protein and clinical phenotype expression. This is the first report of a patient with homozygous sarcoglycan gene mutation without overt muscle weakness in his adulthood. The spectrum of clinical phenotypes in sarcoglycanopathies is therefore wider than previously thought.

Adult↗
PubMed1998

Positive correlation of CTG expansion and pharyngoesophageal alterations in myotonic dystrophy patients.

Alteration of the pharyngoesophageal musculature is a common finding in patients with myotonic dystrophy (MD), regardless of the presence of dysphagia. The aim of the present study was to determine whether a specific pattern of swallowing abnormalities could be identified in MD patients, and the possible correlation with the size of CTG repeats. Fifteen MD patients, 8 of whom were asymptomatic for dysphagia, underwent a videofluoroscopic study of swallowing. Alterations of the pharyngoesophageal phase of swallowing were detected in 12 of 15 patients, 6 without clinical evidence of dysphagia. Incomplete relaxation of the upper esophageal sphincter (UES) and esophageal hypotonia were the most common alterations. We found a significant correlation between the number of radiological alterations and the size of CTG repeats. A typical radiological pattern of swallowing has also been identified. The role of videofluoroscopy in evaluation of MD patients is briefly discussed.

Adult↗
PubMed1998

Radiological evidence of subclinical dysphagia in motor neuron disease.

Dysphagia in motor neuron disease (MND) may lead to dangerous complications such as cachexia and aspiration pneumonia. Functional evaluation of the oropharyngeal tract is crucial for identifying specific swallowing dysfunctions and planning appropriate rehabilitation. As part of a multidisciplinary study on the treatment of dysphagia in patients with neuromuscular diseases, 23 MND patients with different degrees of dysphagia underwent videofluoroscopy, videopharyngolaryngoscopy and pharyngo-oesophageal manometry. The results of the three instrumental investigations were analysed in order (1) to define the pattern of swallowing in MND patients complaining of dysphagia; (2) to evaluate whether subclinical abnormalities may be detected; and (3) to assess the role of videofluoroscopy, videopharyngolaryngoscopy and manometry in the evaluation of MND patients with deglutition problems. Correlations between the instrumental findings and clinical features (age of the patients, duration and severity of the disease, presence and degree of dysphagia) were also assessed. The results of our study showed that: (1) The oral phase of deglutition was compromised most often, followed by the pharyngeal phase. (2) In all patients without clinical evidence of dysphagia, subclinical videofluoroscopic alterations were present in a pattern similar to that found in the dysphagic group. (3) Videofluoroscopy was the most sensitive technique in identifying oropharyngeal alterations of swallowing. Impairment of the oral phase, abnormal pharyngo-oesophageal motility and incomplete relaxation of the upper oesophageal sphincter were the changes most sensitive in detecting dysphagia. Videofluoroscopy was also capable of detecting preclinical abnormalities in non-dysphagic patients who later developed dysphagia. Practical guidelines for the use of instrumental investigations in the assessment and management of dysphagia in MND patients are proposed.

Adult↗
PubMed1998

Biological effects of a neurotoxic pesticide at low concentrations on sea urchin early development. A terathogenic assay.

Dose-dependent terathogenic effects of an organophosphate insecticide were found during early sea urchin development. This biological assay is low cost, easy to measure, and allows to detect the effects of the exposure of organisms to the active principle at concentrations lower than the acceptable daily intake (ADI) for man. Effects were found independently from the stage of exposure, and were major as earlier exposure occurred. The stronger effects were exerted on the elongation of the skeletal rods, that was easily measured by following the migration of primary mesenchyme cells, labelled by WGA (wheat germ agglutinin).

Animals↗