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Biomedical subjects

G Moretto

Publications and source records attributed to G Moretto.

At least 19 recordsLinked to original sources
PubMed1992

Complement neoantigen and vitronectin are components of plaques in amyloid AL neuropathy.

We studied three patients with late onset, chronic sensorimotor and autonomic neuropathy in course of plasma cell dyscrasia with Bence Jones proteinuria. Histopathological findings of nerve biopsies consisted in diffuse loss of myelinated and unmyelinated fibers associated with perivascular deposits of amorphous material with physico-chemical and ultrastructural features of amyloid. By immunohistochemistry, light chains of the same type as Bence Jones protein, components of the classic and lytic pathways of the complement and vitronectin were detected at the level of amyloid nodules. The colocalization of complement neoantigen and vitronectin suggests that this complex derives from the circulation. The elucidation of the chemical composition of amyloid might shed some light in the pathogenesis of these disorders.

Amyloidosis↗
PubMed1991

Cytoskeletal changes induced by 2,5-hexanedione on developing human neurons in vitro.

Dissociated dorsal root ganglion cells from human fetuses were exposed to 2,5-hexanedione (2,5-HD) for 2 weeks. Morphological changes induced by 2,5-HD consisted in focal neurofilament (NF)-containing enlargements preferentially located in distal, preterminal regions of unmyelinated fibers. Tangles of NF were also observed in the perikarya of nerve cells. Morphometric analysis disclosed that the cross-sectional areas of the 2,5-HD treated axons were 30% smaller than those of control axons. This alteration was associated with reduction of number of NF per unit area. These findings demonstrate that 2,5-HD treatment induces a generalized disorganization of neuronal and axonal NF responsible for focal enlargements as well as atrophic changes of unmyelinated fibers.

Axons↗
PubMed1990

Complement-mediated demyelination in patients with IgM monoclonal gammopathy and polyneuropathy.

We investigated the role of complement in the pathogenesis of the demyelinating polyneuropathy that occurs in some patients with IgM monoclonal gammopathy. Seven patients with chronic sensorimotor polyneuropathy and IgM monoclonal gammopathy were examined. In six patients, the monoclonal protein recognized an epitope shared by myelin-associated glycoprotein and two peripheral-nerve glycolipids, whereas in one patient, IgM bound to an unidentified myelin antigen. Direct and indirect immunofluorescence and immunoperoxidase assays showed colocalization along the myelin sheaths of peripheral-nerve fibers of monoclonal protein with complement components C1q, C3d, and C5. In addition, terminal-complement complex that was not associated with S protein was detected in myelin sheaths. It appeared that alterations in myelin geometry caused by the separation of myelin lamellae corresponded to sites at which terminal-complement complex was deposited. We conclude that demyelination in polyneuropathy associated with IgM monoclonal gammopathy may be mediated by complement.

Aged↗
PubMed1990

Familial spastic paraplegia with peroneal amyotrophy. A family with hypersensitivity to pyrexia.

We describe 4 siblings with spastic paraparesis and peroneal amyotrophy who were prone to severe pain and painful dysesthesias, tetraparesis and pyramidal signs during pyrexial episodes of variable etiology. These symptoms cleared almost completely in 10-20 days. Nerve conduction velocity was reduced more markedly during the spells of fever. Muscle biopsy specimen was normal. Some transient functional disturbance of membrane equilibrium of the nervous pathways of both central and peripheral nervous systems was probably responsible for the attacks during pyrexial episodes.

Adolescent↗
PubMed1989

Recurrent familial brachial plexus palsies as the only clinical expression of 'tomaculous' neuropathy.

Two familial cases of recurrent brachial plexus are described and similar episodes were noticed in other members of the family. Electrophysiological investigations found impaired motor and sensory nerve conduction velocity in affected and nonaffected members. Tomaculous neuropathy was found at biopsy of peripheral nerve in more than 40% of dissected fibers. In addition, two affected members showed a reduced interpupillary distance, i.e. the most common dysmorphic feature found in the hereditary neuralgic amyotrophy (HNA). A literature review showed only two other instances of recurrent familial brachial plexus palsies as the only manifestation of tomaculous neuropathy (hereditary neuropathy with liability to pressure palsy, HNPP). The dysmorphic feature found in our cases in addition to the clinical, electrophysiological and anatomical data support the hypothesis that these cases of HNPP and the HNA may represent the same disease.

Adult↗
PubMed1987

Binding of monoclonal anti-myelin-associated glycoprotein antibodies to human foetal peripheral neurons in culture.

Dorsal root ganglion cells, obtained from 8-10-week human foetuses, were isolated by enzymatic procedure and grown on poly-L-lysine-coated coverslips. Most of the cultured cells showed the ultrastructural and immunological features of normal peripheral neurons. By immunocytochemistry neurons reacted with IgM antibodies with specificity for myelin-associated glycoprotein (MAG) from patients affected with IgM k gammopathy and peripheral neuropathy. The antigen was located on the plasmalemma of both perikarion and axon. We suggest that anti-MAG antibodies do not recognize neuronal MAG, but rather an epitope shared with different glycoproteins.

Antibodies, Monoclonal↗
PubMed1986

Neuroimmunology of gangliosides in human neurons and glial cells in culture.

Gangliosides (sialic-acid-bearing glycolipids) have received attention in recent years because of their role in cell recognition phenomena, synaptic transmission, memory generation, and nerve regeneration in the fields of neurosciences. It is suggested that each brain region or each neural cell type may contain a specific and characteristic set of gangliosides. We have investigated the immunocytochemical localization of several classes of gangliosides that include GM1, GM4, GD3, and GQ gangliosides on the cell surface of various cell types found in human neural cell cultures with antibodies specific for these gangliosides. Cell cultures were obtained from adult human brains and fetal human dorsal root ganglia and spinal cord and cultured in vitro for the period up to 6 months and utilized for the ganglioside immunocytochemistry. It was demonstrated that GM1 ganglioside was present in all galactocerebroside-positive oligodendrocytes and most of glial fibrillary acid protein (GFAP)-positive astrocytes (80%), most of neurofilament-positive neurons (80%), 50-70% of Schwann cells, and 5-10% of fibronectin-positive fibroblasts; GM4 ganglioside could be detected in all oligodendrocytes, 80% of astrocytes, and 50% of Schwann cells, while no staining was found in neurons or fibroblasts; GD3 ganglioside was present in all oligodendrocytes and 5-10% of astrocytes but not in neurons, Schwann cells, or fibroblasts; and all of fetal CNS neurons and approximately 80-90% of fetal dorsal root ganglia (DRG) neurons and a small percentage of astrocytes (10-20% in fetal and less than 1% in adult astrocytes) was labeled by A2B5 antibody which is specific for GQ ganglioside, while this antibody did not stain cell surface of oligodendrocytes, Schwann cells, or fibroblasts. Three classes of gangliosides, GM1, GM4, and GD3 were found to be definite components of fetal and adult human oligodendroglial plasma membrane, while GM1 and GM4 gangliosides were detected on the surface of most astrocytes. Only a minor population of astrocytes from both fetal and adult human CNS contained GD3 and GQ gangliosides. Two classes of gangliosides, GM1 and GQ, were detected on the surface of fetal human neurons. More than half of fetal Schwann cells reacted to GM1 and GM4 antibodies but did not to GD3 or GQ antibodies. We recognized the presence of a specific and characteristic set of gangliosides on the cell surface of different human neural cell types and these findings should facilitate further investigation of the precise biological activity of these gangliosides.

Aged↗
PubMed1985

Isolation, culture and cell-type identification of adult human pituitary cells.

Pituitary cells were isolated from adult human pituitary glands obtained at autopsy 4-12 h postmortem by enzyme treatment (collagenase and dispase) and by Percoll density gradients. Cells thus isolated were maintained in culture for more than 6 months. By immunoperoxidase staining methods using rabbit sera monospecific against various pituitary hormones, a large number of cultured cells reacted positively. The hormones identified in these cells were growth hormone, prolactin, adrenocorticotropin, follicle-stimulating hormone, luteinizing hormone and thyrotropin. Electron-microscopic examination of cultured cells revealed the presence of secretory granules in cytoplasm characteristic of in vivo human pituitary cells.

Adolescent↗
PubMed1985

Expression of Ia antigens on the surface of human oligodendrocytes and astrocytes in culture.

Oligodendrocytes and astrocytes were isolated from normal adult human brains 3-15 h postmortem using a Percoll density gradient centrifugation and were cultured for 10-135 days. The presence of HLA-DR(Ia) antigens on the surface of these human oligodendrocytes and astrocytes was studied using double immunofluorescence procedures. Only half of separate culture series (6/12 donors) contained HLA-DR-positive oligodendrocytes, while all of the culture series (12/12 donors) revealed HLA-DR-positive astrocytes. Among the HLA-DR-positive cultures, 4-16% of galactocerebroside-positive oligodendrocytes and 9-24% of GFAP-positive astrocytes were found to immunoreact with HLA-DR antibody. The presence of Ia antigens on the surface of certain populations of oligodendrocytes and astrocytes may be important in the induction of an immune response to these cells.

Adult↗
PubMed1985

Survival and growth of adult human oligodendrocytes in culture: scanning electron microscopy.

The oligodendrocytes in culture serve as an important model for the study of demyelination diseases. We have previously originated a method of isolating human oligodendrocytes. In order to establish their three dimensional morphology, scanning electron microscopy of the cultured oligodendrocytes was performed. The oligodendrocytes bulk isolated from adult human brain were maintained in culture for more than 2 months. At the various periods in culture, the cells were studied by scanning electron microscopy and immunofluorescence staining using marker antibodies for the identification of oligodendrocytes. The three dimensional organization and the surface morphology of the cultured oligodendrocytes were investigated. They displayed an extensive network of the cell processes and characteristic surface morphology.

Adult↗
PubMed1985

The growth of fetal human sensory ganglion neurons in culture: a scanning electron microscopic study.

Sensory neurons of 8-week human fetal dorsal root ganglia were dissociated into single cells by trypsinization and cultured on coverslips for 4 months, in either serum-containing or serum-free chemically defined media. At different times the cultures were fixed and prepared for scanning electron microscopy. Fetal sensory neurons in culture regenerated axons within 24 hours which were characterized by axonal growth cones at their tips and the neuronal perikarya assumed spherical or a bonnet-like morphology.

Axons↗
PubMed1984

Culture and cryopreservation of adult human oligodendrocytes and astrocytes.

Human adult oligodendrocytes were bulk-isolated from the brains obtained at autopsy by the Percoll density gradient method and cultured in vitro for 2-28 days. Cultured human oligodendrocytes were then scraped from the dishes or coverslips, frozen at -70 degrees C in the presence of 10% dimethyl sulfoxide as a cryoprotectorant, and then stored in liquid nitrogen tank. After the fast thawing, 55%-70% of human oligodendrocytes plus astrocytes were found to survive in the culture. Identification of cell types was established by using antibodies directed against galactocerebroside (oligodendrocyte) and glial fibrillary acidic protein (astrocyte).

Astrocytes↗
PubMed1984

Long-term cultures of human adult Schwann cells isolated from autopsy materials.

Enriched populations of adult human Schwann cells were obtained from trigeminal ganglia and roots of autopsy material. The cells, isolated by enzymatic procedure, were seeded on rat tail collagen-coated coverslips. Subcultures were established several weeks later, and secondary cells were grown on polylysine-coated coverslips and maintained in vitro for as long as 5 months. The Schwann cells in culture displayed the same light- and electron-microscopic features and arrangement as those cells observed in vivo. The addition of bovine pituitary glial growth factor in the medium induced a 3-5-fold increase in Schwann cell division.

Adult↗
PubMed1983

Histopathological and ultrastructural study of a case of infantile metachromatic leukodystrophy.

The histopathological and ultrastructural findings on a nerve biopsy specimen and on a CNS necropsy specimen in a case of IML with a typical clinicaL course are reported. Nerve biopsy once again proved to be a sure diagnostic guide even at an early stage of the disease. Some differences in the fine structure of the cytosomes between the nerve biopsy and CNS necropsy material studied four years later may be due to the different rates of catabolism of the constituent lipids as well as to post mortem artefacts.

Brain↗
PubMed1982

Chronic relapsing polyneuritis. A light- and electron-microscopic study.

The clinico-pathologic findings in two patients with chronic relapsing polyneuritis are reported. The patients had several attacks of diffuse polyneuritis followed by partial recovery. The tendency to persisting disability increased following relapses and in the late stages there was a progressive motor deterioration suggesting a continuing activity of nerve damage. The biopsies of peripheral nerves, obtained in the advanced stages of the disease, showed severe loss of myelinated fibers and aspects of repeated demyelination and remyelination, with formation of onion bulb complexes. Completely demyelinated axons together with remyelinating fibers as well as remyelinated fibers invested by macrophages were seen at the same time. The clinical and pathological evidences suggest that in chronic relapsing polyneuritis, at least in the late stages of the disease, besides clinical relapses, there is a continuing activity of nerve damage. Thus, due to this ongoing activity of demyelination and remyelination, the elimination of the supernumerary Schwann cells does not take place satisfactorily and hypertrophic changes of the nerve fascicles are produced.

Aged↗
PubMed1981

Friedreich's ataxia. A light- and electron microscopic study of peripheral nerve biopsies.

Sural or superficial peroneal nerve biopsies of patients with clinical diagnosis of Friedreich's ataxia were studied. Patients were divided in two groups, typical and abortive forms: loss of fibers accompanied by axonal atrophy and segmental demyelination are the basic changes in both groups, although the decrease in number of myelinated fibers was most severe in typical FA. In the cases with slower progression there is a tendency to form onion bulb complexes.

Atrophy↗