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Biomedical subjects

G Meola

Publications and source records attributed to G Meola.

At least 19 recordsLinked to original sources
PubMed1991

Increased acetylcholine sensitivity in Duchenne muscular dystrophy myotubes.

Monolayer cultures were established from explants of muscle obtained from 6 patients with Duchenne muscular dystrophy (DMD) and 9 controls. Electrophysiological studies were made after 3-4 weeks in vitro, when many myotubes had formed. An intracellular electrode was used to record cell membrane potential, and acetylcholine was applied by ionophoresis. The myotubes grown from Duchenne muscle showed greater acetylcholine sensitivity than controls.

Acetylcholine↗
PubMed1991

Hereditary human myopathies in muscle culture.

In this article I illustrated the use of regenerating human muscle cultures for studying the hereditary human myopathies. Although some of the data are still controversial, they do point up the great potential of this "in vitro system". For hereditary myopathies due to developmentally regulated proteins that are expressed only at a more advanced stage of muscle differentiation, the use of highly differentiated nerve-muscle cocultures might contribute significantly to a better understanding of their developmental pathogenesis. More advanced techniques (permanent human muscle cell lines, heterokaryons, myoblast transfer, gene transfer, myogenic conversion of human non-muscle cells, cybrid clones) may provide a great deal of information at molecular level and may also have practical applications in the diagnosis or even in the treatment of hereditary human myopathies.

Cells, Cultured↗
PubMed1991

In vitro genetic transfer of protein synthesis and respiration defects to mitochondrial DNA-less cells with myopathy-patient mitochondria.

A severe mitochondrial protein synthesis defect in myoblasts from a patient with mitochondrial myopathy was transferred with myoblast mitochondria into two genetically unrelated mitochondrial DNA (mtDNA)-less human cell lines, pointing to an mtDNA alteration as being responsible and sufficient for causing the disease. The transfer of the defect correlated with marked deficiencies in respiration and cytochrome c oxidase activity of the transformants and the presence in their mitochondria of mtDNA carrying a tRNA(Lys) mutation. Furthermore, apparently complete segregation of the defective genotype and phenotype was observed in the transformants derived from the heterogeneous proband myoblast population, suggesting that the mtDNA heteroplasmy in this population was to a large extent intercellular. The present work thus establishes a direct link between mtDNA alteration and a biochemical defect.

Cell Line↗
PubMed1991

Lysosomotropic agents induce morphological and functional changes in human muscle cells in vitro.

We studied the distribution of lysosomes in differentiating human muscle cells in culture treated with propranolol, leupeptin and chloroquine. Chloroquine treated cells showed a significant vacuolization and an increase of the lysosomal apparatus as assessed by cytochemical analysis of the lysosomal enzyme acid phosphatase and by acridine orange staining. At electron microscopic level, an increase of lysosome-like bodies and disorganization of the contractile apparatus were demonstrated in multinucleated myotubes. These alterations observed in cultured muscle cells suggest that lysosomotropic agents may be harmful.

Cells, Cultured↗
PubMed1991

Growth and differentiation of myogenic clones from adult human muscle cell cultures.

Clonal cultures only recently have been applied to normal and pathological human muscle, but detailed clonal analysis and differentiative properties of individual long term muscle subclones derived from adult normal human muscle cell (HMC) cultures have not been reported. In this study we compared the growth potential by plating efficiency (PE), muscle colony differentiation (MC) and growth cuvers and the differentiative properties by fusion index, dystrophin localization, creatine kinase (CK) total activity and isozyme electrophoresis in HMC cultures derived myogenic subclones. These properties were tested in two experimental culture systems (200 cells/dish versus single cell/well) and with two tissue culture media (standard medium--MM--versus conditioned medium--CM). We found a significant high PE and MC in clonal cells established with single cell/well and grown in conditioned medium. In derived subclones we observed two classes of myogenic cells: one characterized by exponential growth kinetic, branched myotubes with high fusion index and predominantly sarcolemmal distribution of dystrophin and MM band at CK electrophoresis; the other with flat growth curve, low fusion index and low CK total activity. These findings demonstrate the variability of the expression of myogenic potentials in cells cloned from adult normal HMC cultures and represent an important tool for comparing the various cell types present in normal and diseased human muscle and for transplantation of normal myoblasts in Duchenne Muscular Dystrophy.

Adult↗
PubMed1990

A case of mitochondrial myopathy, lactic acidosis and complex I deficiency.

A 34-year-old man affected by exercise intolerance, mild proximal weakness and severe lactic acidosis is described. Muscle biopsy revealed mitochondrial abnormalities and an increase of cytochrome c oxidase histochemical reaction. Biochemical investigations on isolated muscle mitochondria as well as polarographic studies revealed a mitochondrial NADH-CoQ reductase (complex I) deficiency. Mitochondrial dysfunction was confirmed by 31P nuclear magnetic resonance spectroscopy. Immunological investigation showed a generalized reduction of all complex I polypeptides. Genetic analysis did not reveal mitochondrial DNA deletions. The biochemical defect was not present in the patient's muscle tissue culture. Metabolic measurements and functional evaluation showed a reduced mechanical efficiency during exercise.

Acidosis, Lactic↗
PubMed1990

Kearns-Sayre syndrome: different amounts of deleted mitochondrial DNA are present in several autoptic tissues.

A population of deleted mitochondrial DNA (mtDNA) was found in different amounts in autoptic muscle, heart, cortex, cerebellum, liver and kidney of a patient who died of Kearn-Sayre Syndrome (KSS). The widespread occurrence of the deletion correlates with the multisystem nature of KSS and supports the hypothesis that this is a genetic disease due to an alteration of mtDNA presumably arising in the oocyte or early embryo.

Brain↗
PubMed1989

Properties of acetylcholine-receptor activation in human Duchenne muscular dystrophy myotubes.

In human myotubes cultured from biopsies of normal subjects and dystrophic patients we investigated, with the patch-clamp technique, the activation properties of the nicotinic acetylcholine receptor (AChoR) in the presence of acetylcholine and suberyldicholine. The single-channel conductance and the lifetime of the openings were not found to differ. In contrast, the average frequency of openings was about four times higher in Duchenne muscular dystrophy (DMD) myotubes in the presence of equal amounts of acetylcholine, but not of suberyldicholine. The most reasonable conclusion from this observation is that the behaviour of the AChoR is not altered in DMD cells but that there is a greater average concentration of ACho molecules present around AChoRs. This leads to the tentative conclusion that the activity of the enzyme acetylcholinesterase (AChoE) is impaired by some unknown mechanism in the dystrophic myotube.

Acetylcholine↗
PubMed1989

Muscle glucose-6-phosphate dehydrogenase deficiency.

Muscle glucose-6-phosphate dehydrogenase (G6PD) deficiency is described in four clinically heterogeneous patients: an athlete who developed myoglobinuria after physical exercise; a 7-year-old, mildly mentally retarded boy, who had episodes of dark urine and high creatine kinase; and two brothers of Sardinian origin, the elder showing moderate exercise intolerance. Histochemical and biochemical studies showed a lack of G6PD activity in muscle biopsy specimens as well as in erythrocytes. G6PD characterization in erythrocytes classified these mutant enzymes as Mediterranean variant in all the patients. The deficiency was confirmed in the patients' myotubes and skin fibroblasts, where residual activity was present. Electrophoretic studies in tissue culture extracts showed that the residual muscle enzyme migrated as a single electrophoretic band like normal human muscle G6PD.

Adolescent↗
PubMed1989

Danazol and internal carotid artery thrombosis.

The case of a 47-year-old woman suffering from a CT-assessed ischemic right hemisphere stroke, which occurred after a 2-month treatment with danazol (a synthetic androgen), is reported. The patient's thrombocytosis in association with danazol treatment and its possible correlations with the thrombotic event are discussed.

Carotid Artery Thrombosis↗
PubMed1989

[Mitochondrial encephalomyopathy].

Modern concepts regarding mitochondrial encephalomyopathies (ME) are summarized. Utilizing recent techniques of molecular biology we studied some cases of ME referred to the Institute of Clinical Neurology of Milan University. With these techniques we demonstrated different mitochondrial DNA deletions either in patients' muscle or in culture.

Adolescent↗
PubMed1989

Mitochondrial myopathies: morphological and biochemical studies in human muscle cultures.

The mitochondrial myopathies are a heterogeneous group of disorders presumed to be caused by primary mitochondrial dysfunction with impairment of energy provision from oxidative metabolism. An increasing number of specific functional mitochondrial deficiencies have been documented and recently new strategies are beginning to analyze molecular and genetic mechanisms. Nevertheless these specific disorders have not been studied extensively in human muscle cultures. The objectives of our study were to reproduce morphological and biochemical changes in cultured myotubes of three Kearns-Sayre syndrome (KSS) patients to evidentiate a different mitochondrial susceptibility to 2-4 dinitrophenol (DNP) into normal and KSS muscle cultures, and to investigate the protective effect of ubidecarenone (Q10) on KSS myotubes exposed to DNP. In KSS cultures as compared to normal ones no abnormalities in growth pattern and differentiation were observed. KSS myotubes DNP exposed showed some abnormally large mitochondria with parallel-packed cristae and decrement in all mitochondrial enzymes activity ranging from 20 to 40%. In normal myotubes DNP exposed and in patient cultures DNP-Q10 treated a normal mitochondrial morphology and a recovery of enzymatic activity was found. In Complex I deficiency patient cultured myotubes cytochemical, immunocytochemical, ultrastructural and biochemical studies were performed and no abnormalities were found. Negative tissue culture findings could be explained by the fact that the defect cannot be reproduced in aneural cultures, and that there could be a gradual selection of cells containing a preponderance of wild type mitochondria over those that contain mutant mitochondria.

Cells, Cultured↗
PubMed1989

Nile red simultaneous staining of intracellular lipids and membrane network in human muscle cultures.

We have applied a new fluorescent probe, Nile red, on normal and pathological human muscle derived cultures and compared the results with corresponding human muscle sections. In normal human muscle cultures, Nile red strain has proved useful for visualization of both intracellular lipids and membrane network. Similar patterns have been observed in muscle cultures derived from lipid storage and mitochondrial myopathies. Moreover, abnormalities in pathological muscle cultures could be revealed by establishing more advanced culture systems.

Cells, Cultured↗
PubMed1988

Cultures of human Schwann cells isolated from fetal nerves.

We describe a technique for the preparation of highly purified populations of Schwann cells (SC) from human fetal nerves. Cultures were prepared by chemical and mechanical dissociation of human fetal sciatic nerves by modification of the method of Kreider et al. developed for newborn rat nerve. A time course analysis of some SC-associated markers at different times in vitro was performed employing immunofluorescence (IF) and immunoperoxidase (IP) to determine the percentage of SC in culture and to evaluate the maintenance of specific SC characteristics. We compared this method with that of Askanas et al. which produces enriched SC cultures by utilizing successive re-explantation of the original nerve explant. After 48 h, approximately 90% of the cells were bipolar and S-100+ and over the next two weeks about 70-80% of cells were SC by cytologic and immunocytologic criteria. At 35 days, 35% were SC, whereas less than or equal to 2.5% of 35-day-old multi-explant cultures were SC. The SC obtained by this method displayed the typical morphological and immunological characteristics: they expressed surface laminin and nerve growth factor receptors, whereas fibronectin, which is localized on fibroblast surface, was absent.

Cell Separation↗
PubMed1988

Low doses of ketazolam in anxiety: a double-blind, placebo-controlled study.

A multicenter, double-blind, between-patient trial comparing two doses of ketazolam (15 and 30 mg) with placebo, each given once daily, in the evening, to 92 outpatients affected by generalized anxiety disorders for at least 1 month, was carried out. After 1-week washout period 47 patients were randomized to ketazolam 15 mg, and 45 to placebo for 15 days (first period). At the end of this period, if the patient experienced a decrease on the total Hamilton Anxiety Rating Scale (HAM-A) of at least 25% of basal value, the treatment was kept unchanged for a further 15 days, otherwise 15 mg of ketazolam were added to the previous treatment (second period). Anxiety was rated after 2 and 4 weeks with the Italian HAM-A scale and with a 4-point scale (patient's assessment). Seventy-eight patients completed the first period and 75 the whole study. During the first period the percentage of responders was almost identical in both treatment groups, but during the second period a further slight improvement was observed in the early placebo responders, while the HAM-A score of patients on ketazolam continued to improve significantly (p less than 0.01) throughout the study. Likewise a significant (p less than 0.001) difference between treatments was observed, on the 4-point scale, in the population as a whole (end of first period) as well as in responder patients (end second period). Tolerability was good, except in 1 patient on placebo, who was withdrawn from the study because of severe headache.

Adolescent↗
PubMed1987

Recessive carnitine palmityl transferase deficiency: biochemical studies in tissue cultures and platelets.

In a new case of carnitine palmityl transferase (CPT) deficiency the defect was documented in muscle and muscle cultures with an isotope exchange reaction, using different concentrations of palmityl-DL-carnitine and a forward reaction with and without albumin. The defect was expressed in cultured skin fibroblasts only by the "reverse" and "hydroxamate" reactions. The parents and the patient's daughter had intermediate levels of the enzyme in platelets and fibroblasts, supporting the concept that CPT deficiency has an autosomal recessive pattern of inheritance. The growth pattern and development of muscle cultures in this CPT-deficient patient indicate that CPT activity may be sufficient to allow normal muscle differentiation in culture without lipid storage.

Acyltransferases↗