Biomedical subjects
Publications and source records attributed to E Scarpini.
The uncommon case is described of a girl severely affected with Duchenne muscular dystrophy. Cytogenetic analysis revealed no numerical or structural abnormalities of the X-chromosome in any of the cells examined (leucocytes and myoblasts). No abnormality in morphology, growth pattern or differentiation was observed in the dystrophic muscle cultures as compared with control cultures.
Human fetal and adult Schwann cells, which had been maintained in culture for 5 weeks according to an explant-reexplantation technique, were labeled by immunoperoxidase using antibodies directed against S-100 protein and laminin in order to find specific antigenic markers. Immunocytochemical analysis of the distribution of both proteins showed that they were expressed in long-term cultures. The localization of S-100 protein and laminin in long-term cultures indicated that the expression of these proteins by human Schwann cells was not axon-dependent and also occurred in absence of myelin synthesis.
The cell surface antigen distribution on traumatic neuroma Schwann cells and neurofibroma Schwann-like cells was characterized using monoclonal antibodies that define melanoma-associated antigens. Immunofluorescence staining of cultured cells, immunoprecipitation of radioiodinated antigens from cells placed in short-term cultures, and immunoperoxidase staining of frozen tissue sections revealed most of the melanoma-associated antigens tested on traumatic neuroma and neurofibroma Schwann cells and on fetal and adult femoral nerve. The cross-reactivity of the antibodies with neural cells may reflect the common neural crest embryological origin of Schwann cells and melanocytes. Cell sorter analysis of neurofibroma cells using a monoclonal antibody directed against the melanoma nerve growth factor receptor resulted in cell cultures highly enriched for Schwann-like cells which may bear the genetic defect responsible for neurofibromatosis. The antigen detected by this monoclonal antibody is the neurofibroma nerve growth factor receptor and the antibody was a potent inhibitor of nerve growth factor binding to neurofibroma cells.
Fibronectin expression during human muscle differentiation was investigated by determining its distribution in foetal, normal adult and dystrophic muscle and in foetal, normal adult and dystrophic muscle cultures during myogenesis. Muscle sections and muscle cultures were studied by indirect immunofluorescence staining using polyclonal and monoclonal anti-human antibodies. Mass and clonal muscle cultures were prepared from foetal, adult and dystrophic muscle tissue. Immunofluorescence staining detected fibronectin on the epimysium, perimysium and endomysium of transverse sections of normal adult muscle, while sarcoplasm was devoid of this glycoprotein. In foetal muscle, some fibers showed a prominent ring of fibronectin. In mass and clonal cultures, myoblasts were found to synthesize and accumulate fibronectin while myotubes did not. No difference in fibronectin distribution was observed between Duchenne Muscular Dystrophy (DMD) and control myotubes. An enzyme-linked immunoassay (ELISA), performed on homogenated muscle, sonicated fibroblasts and muscle cells, showed a high fibronectin level in fibroblasts when compared with the other samples tested.
Muscle biopsies from two sporadic cases of congenital nemaline myopathy were examined for myosin heavy chain composition. Electrophoresis of congenital nemaline myopathy (CNM) muscle myosin in SDS-5% polyacrylamide gels gave rise to a single heavy chain band, with a migration rate and antigenic properties identical to that of the adult slow form, as demonstrated by Western blot techniques and by using specific antibody. Immunofluorescent studies indicate that CNM muscle fibers, including the most severely atrophic fibers, are homogeneous with respect to myosin heavy chain composition.
Previous pyrophosphate-gel studies have reported the existence of embryonic neonatal myosin isoenzymes in human developing muscle. The present investigation was undertaken to characterize their subunit composition more precisely. Two immature muscle myosins are contrasted with adult myosin: neonatal myosin and foetal myosin. The neonatal form of myosin is weakly cross-reactive with rabbit slow myosin and contains only fast-type light chains (LC), LC1F and LC2F. The associated heavy chains consist of a single electrophoretic component that reacts exclusively with antibodies against human foetal myosin and has a mobility and peptide pattern distinct from that of adult fast and slow heavy chains. Foetal myosin is distinguished by the presence of low amounts of a heavy chain immunologically cross-reactive with the adult slow form and of two additional light-chain components: a LC2S light chain and a foetal-specific light chain (LCemb.). The foetal-specific light chain, as shown by one-dimensional-peptide-map analysis, is structurally unrelated to both LC1S and LC1F light chains of human adult myosin. We conclude from these results that the ontogenesis of human muscle myosin shares certain common features with that observed in other species, except for the persistence until birth of a foetal form of heavy chain (HCemb.).
Explore the source record for details and available documents.
Muscle was cultured from a 7-month-old boy affected by generalized weakness, macroglossia, cardiomegaly, hepatomegaly and increasing dyspnea. Muscle biopsy showed a vacuolar myopathy with glycogen accumulation (Pompe's disease). The muscle was cultured to verify whether the abnormality could be expressed in culture during myogenesis. In the living muscle cultures, phase-contrast microscopy revealed that myotubes as young as two weeks were vacuolated and that the vacuolization was higher in the older cultures compared to parallel control cultures. Fluorescent microscopy by acridine orange staining of the cultures showed a marked increase in acridine orange positive material (presumptive lysosomes) throughout the sarcoplasm. Electron microscopic data revealed myofibrillar destruction in the muscle biopsy and vacuolized cytoplasm in the Schwann cells. Cytochemically, the patient's myotubes stained very intensely for acid phosphatases. The increased acid phosphatase activity was quantitatively confirmed by cytophotometric evaluation performed on patient and control parallel myotubes. This is the first evidence that an increase in acid phosphatases has been quantitatively demonstrated in cultured muscle from a patient with acute infantile onset acid maltase deficiency (Pompe's disease) although the enzymatic activity was assayed at only one time of incubation.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
A critical review of the published cases reports suggests that the muscle changes could be induced by Pentazocine by mechanisms other than local myotoxicity. The mechanism of myotoxicity in Pentazocine-myopathy remains uncertain and for this reason a tissue culture study was performed in order to investigate the close relationship between myopathy and Pentazocine. The effects of Pentazocine on the extent of myogenesis in human foetal muscle cultures were investigated. The phase contrast study, the light microscopy the quantitative assessment of myogenesis (the number of nuclei incorporated into myotubes were counted and expressed as a percentage of the total number of nuclei) showed a complete block of myogenesis in Pentazocine treated culture and a delayed fusion process was present in D-arabinofuranosylcytosine (Ara-C)-Pentazocine-treated cultures. The present preliminary data, however, suggest that muscle stem cells could participate in the replacement of skeletal muscle by fibrous tissue in neuromuscular syndrome induced by Pentazocine.
The authors have investigated the uncommon occurrence of a boy affected with Duchenne muscular dystrophy (DMD) whose mother showed myopathic features in the clinical history, EMG, biochemical tests and muscle biopsy. This study suggests that the patient's mother is a manifesting carrier of X-linked DMD with clinical, neurophysiological, biochemical and histological findings of X-linked DMD with an almost complete inactivation of the paternal X-chromosome (lyonization).
Two cases of pentazocine-induced neuromuscular syndrome in addicted patients are reported. Histochemical and histographic analysis of muscle biopsies performed in areas distant from the site of injection, disclosed type II muscle fibre atrophy. In order to clarify the pentazocine myotoxic mechanism, a tissue culture study was performed and the effects of the drug on the extent of myogenesis in human foetal muscle cultures were assayed. The tissue culture studies showed: 1 a complete block of myogenesis in pentazocine-treated human foetal muscle cultures and 2. a delayed fusion process when the pentazocine-treated cultures were pretreated with 10(-5) M D-arabinofuranosylcytosine (ara-C). In conclusion it is suggested that the overgrowth of fibroblasts, supported by tissue culture study, in tissues other than muscle (i.e. nerve) could explain the neurogenic aspects found in these patients.
The carnitine content of the culture media for normal and pathological human muscles, including a case of systemic carnitine deficiency (SCD) was measured and the carnitine concentration was the same in all normal and pathological muscle culture media. Carnitine was never detected in growth medium. Some fibroblasts and myoblasts were filled with neutral lipids in SCD. 14C-palmitate added to the medium was incorporated by SCD fibroblasts or myoblasts to the same concentration as in normal or pathological cells. Factors other than carnitine seem to account for the lipid accumulation of SCD in cell culture.
Explore the source record for details and available documents.
Explore the source record for details and available documents.