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Biomedical subjects

A Bertolotto

Publications and source records attributed to A Bertolotto.

At least 55 records · Page 3Linked to original sources
PubMed1987

The proteoglycan chondroitin sulfate is present in a subpopulation of cultured astrocytes and in their precursors.

We have used an antibody raised against the bovine nasal cartilage proteoglycan chondroitin sulfate (CS) digested with chondroitinase ABC (anti-CS serum) to stain cerebellar glial cells maintained in culture. In cultures grown in the presence of serum, the antibody stained a subclass of GFAP+ astrocytes which we have previously shown to selectively bind the monoclonal antibodies A2B5 and LB1. Also the direct bipotential precursors of these cells, capable of differentiating into GFAP+ astrocytes or into Gal-C+, O1+ oligodendrocytes depending on the culture conditions, were stained, but stopped to produce CS when they differentiated into oligodendrocytes.

Animals↗
PubMed1987

Chondroitin, chondroitin 6-sulphate, chondroitin 4-sulphate and dermatan sulphate proteoglycans in normal and pathological human muscle.

Chondroitin, chondroitin 6-sulphate, chondroitin 4-sulphate and dermatan sulphate proteoglycans were immunolocalized by monoclonal antibodies applied to human muscle sections digested with chondroitinase. In normal muscle the 4 proteoglycans presented a different extracellular localization: unsulphated chondroitin sulphate (chondroitin) was present in the endomysium and around capillaries, chondroitin 6-sulphate in the basal membrane zone, chondroitin 4-sulphate in the vessel adventitia, in the endomysium around capillaries and, to a lesser degree, in the perimysium, dermatan sulphate in the perimysium and, to a lesser extent, in the vessel adventitia and in the endomysium around capillaries. The enlarged endomysium of pathological muscle contained chondroitin and chondroitin 4-sulphate. Chondroitin 6-sulphate and dermatan sulphate did not seem present in the increased connective tissue. No peculiar pattern was observed in the various neuromuscular diseases studied. The specific extracellular distribution, the different biochemical composition and the different ability to bind to other extracellular components suggest a different biological role of these compounds. Chondroitin 6-sulphate is a component of a highly specialized extracellular structure, namely basal membrane. Chondroitin and chondroitin 4-sulphate participate in the composition of actively changing extracellular matrix such as the endomysium in pathological muscle. On the other hand, dermatan sulphate is a constituent of the perimysium that is a more static extracellular structure.

Antibodies, Monoclonal↗
PubMed1986

Immunohistochemical study of chondroitin sulfate in human gliomas.

A polyclonal rabbit antiserum was utilized to localize chondroitin sulfate in human gliomas. Tissue sections were digested with chondroitinase ABC to create the antigenic determinant on the chondroitin sulfate proteoglycan molecule. Normal CNS tissue showed a positive immunohistochemical staining both in white and gray matter, sparing the cytoplasm of glial and neuronal cells. Differentiated astrocytomas presented the same pattern as the normal CNS. Anaplastic astrocytomas and glioblastomas showed progressive reduction of parenchymal positivity as anaplasia increased. These data suggest that chondroitin sulfate is a character expressed by differentiated CNS cells and that it is lost with dedifferentiation. Vascular structures presented positive material in the adventitia in all the oncotypes. A discontinuous positivity was observed in the basal membrane zone of the vessels.

Astrocytoma↗
PubMed1986

Glycosaminoglycan changes in human gliomas. A biochemical study.

Glycosaminoglycans (GAGs) were isolated, separated by electrophoresis and quantified in 36 neurosurgical specimens of human gliomas and in 8 samples of normal white and gray matter. Gliomas of various degrees of malignancy exhibited different GAG patterns. Total GAG concentration was three times higher in low grade gliomas than in normal white matter. The mean percentage of single GAG classes was usually similar in both tissues, although in certain tumor samples a higher percentage of hyaluronate was found. GAG patterns in anaplastic astrocytomas, however, more closely resembled normal white and gray matter, both quantitatively and qualitatively. Glioblastomas, on the other hand, showed high GAG concentrations, in particular of heparan sulfate and dermatan sulfate. This finding could be secondary to the abundant vessels and mesodermal material associated with this oncotype. The hyaluronate/sulfated GAGs ratio was lower in oligodendrogliomas than in low grade astrocytomas. This biochemical feature may be correlated with the alcianophilia found in the honey-comb degeneration of oligodendrogliomas. The significance of these findings as they relate to tumor histology and biology have been discussed.

Brain Neoplasms↗
PubMed1986

Immunohistochemical localization of chondroitin sulfate in normal and pathological human muscle.

The immunohistological localization of chondroitin sulfate (CS) has been studied in normal and pathological human muscle. The bovine nasal cartilage proteoglycan digested with chondroitinase ABC (BNC-PG-Ch ABC) has been utilized for the production of a rabbit polyclonal antiserum. In vitro studies showed that the antiserum binds to the unsaturated disaccharide that remains attached to the core protein after digestion of the CS chains with chondroitinase ABC (Ch ABC). As the disaccharide is created specifically by Ch ABC digestion of the CS chains, the antiserum allows the immunolocalization of CS on tissue sections digested with Ch ABC. The immunohistochemical study on normal and pathological muscle demonstrated a localization of CS in all the extracellular structures: endomysium, perimysium, muscle spindle capsule and intrafusal space. In pathological conditions, the CS was raised in all the cases with increased connective tissue, showing a pattern comparable to that obtained with fibronectin and collagen III. None of the pathological conditions displayed any peculiar character of CS distribution. This finding does not support a primary role for CS in the pathogenesis of muscular dystrophy.

Antibody Specificity↗
PubMed1984

Collagenase in the immunohistochemical demonstration of laminin, fibronectin and factor VIII/RAg in nervous tissue after fixation.

The effects of collagenase on the immunohistochemical demonstrability of laminin, fibronectin and Factor VIII/RAg in human nervous tissue have been studied. The influence of this, and other proteolytic enzymes such as pepsin and trypsin, has been investigated in relation to different fixatives. Collagenase gave better results with Carnoy fixed material than after formalin fixation; unlike trypsin and pepsin, it did not produce tissue digestion.

Antigens↗
PubMed1983

Biochemical and histochemical evaluation of glycosaminoglycans in brain tumors induced in rats by nitrosourea derivatives.

The occurrence, distribution and concentration of GAGs in ENU and MNU experimental brain tumors induced in the rat are reported. GAGs have been histochemically studied by Alcian Blue methods; they have been quantified and qualitatively evaluated by electrophoresis of brain extracts. The pattern of GAGs in normal rats is consistent with the data of the literature. No GAG accumulation precedes the tumor development. Early neoplastic proliferations, oligodendroglial and mixed glial microtumors are strongly alcian-positive; the alcianophilia spares clusters of cells developing a cytoplasm. In large tumors, GAGs are histochemically demonstrable in the honey-comb areas of oligodendrogliomas and in peripheral infiltration areas of polymorphic gliomas. The role of the normal nervous tissue and oligodendroglial cells in the accumulation of the GAGs is discussed. The accumulated GAGs seem to rise from the nervous tissue included in the tumors, rather than from the metabolism of tumor cells.

Age Factors↗
PubMed1982

Glycosaminoglycans in human cerebral tumors. Part II. Histochemical findings and correlations.

The occurrence and the distribution of GAGs have been studied histochemically in 224 human cerebral tumors by means of Alcian blue techniques. In the normal peritumoral gray matter the alcianophilia is stronger than in the white matter and demonstrated the presence of HA and CS. In the glioma group the alcianophilia, due to HA and CS, is mainly related to the presence of infiltrated cortex. In the other tumors, GAGs are histochemically disclosed in relation to collagen, reticulin, mesodermic areas, etc. The vessels of every tumor show a positive staining for HA, CS and HS. The histochemical findings are consistent with the biochemical ones as reported in Part I, even though the significance of GAGs in cerebral tumors remains unknown.

Astrocytoma↗
PubMed1981

The significance of minimal alterations in muscle biopsy of Duchenne carriers.

In order to define the significance of minimal histological and ultrastructural abnormalities in Duchenne carriers, 18 normal healthy volunteers were examined by muscle biopsy. Light microscopy evidenced occasional internal nuclei and less frequent small round and angular fibres. Variability of fibre size, increase in connective tissue, necroses and basophilia found in carriers were not present in controls. Histograms constructed on ATPase stain sections demonstrated variability in distribution of fibre types both in normals and in carriers. Fibre size was more variable in carriers, where a significant decrease of the size of type II B fibres was observed. Electron microscopy evidenced knots in overcontraction, myofibrillary widening, subsarcolemmal accumulation of mitochondria and Z band streaming, which have been reported also in carriers. The results are discussed and compared with the data of the literature.

Adult↗
PubMed1981

Myoglobinuria: presentation of personal cases and review of the literature.

The presence of myoglobin in the urine is a symptom of rhabdomyolysis occurring in many muscular affections. Muscle tissue from seven patients who had presented one of more episodes of myoglobinuria has been studied by histological, histochemical, and biochemical methods. Three cases belonging to the same family and an additional one revealed a muscular CPT deficiency. Two of those cases were females. In two other cases a toxic etiology was suggested, one due to heroin and the other to associated fenfluramine and phenformin. In the last case the origin of rhabdomyolysis was not clearly defined and viral infection, drug intolerance or electrolytic imbalance were proposed. The cases are discussed in the light of the literature and the possible etiopathogenetic mechanisms are reviewed.

Adolescent↗
PubMed1981

Epidemiology of Duchenne muscular dystrophy in the province of Turin.

An epidemiological investigation on Duchenne muscular dystrophy in Turin and its province has been carried out for the period 1955-974. The incidence of the disease proved to be 24 X 10(-5), and the prevalence 2.15 X 10(-5). The mutation rate was 80 X 10(-6). The data are compared with the literature. Segregation analysis on many families was performed in order to find the theoretical number of carrier among Duchenne mothers. The importance of epidemiology for genetic counselling is stressed.

Child↗
PubMed1980

Motor neuron disease following poliomyelitis. Bioptic study of five cases.

5 cases of late motor neuron degeneration following poliomyelitis are presented. CPK, CSF, EMG and spine radiology were studied. In all cases, muscle biopsy evidenced neurogenic alterations both in previously affected limbs and in newly affected ones. Mitochondrial abnormalities were found in 1 case. The findings are discussed in the light of the literature with particular regard to the pathogenesis of the disease. The case with abnormal mitochondria is stressed for the possible relationship of this pathology with systemic degenerative diseases.

Adult↗
PubMed1979

Mitochondrial abnormalities of late motor neuron degeneration following poliomyelitis and other neurogenic muscular atrophies.

A case of late motor neuron degeneration following poliomyelitis with abnormal mitochondria in muscle fibers is presented with two additional cases of systemic neurogenic muscular atrophy (Charcot-Marie-Tooth disease). Muscle biopsy revealed a neurogenic pattern of variable severity in all cases. Subsarcolemmal zones of hyperactivity and hyperpositive intermyofibrillar collections of granular material present in a variable proportion of type I fibers were demonstrated by oxidative enzymes. Ultrastructurally they corresponded to abnormal mitochondria, with paracrystalline inclusions in one case. The finding is discussed in the light of the previous literature on mitochondrial myopathies. Mitochondrial alterations are not specific and their significance in neurogenic conditions is debated.

Adolescent↗
PubMed1978

Two-dimensional immunoelectrophoresis of unconcentrated cerebrospinal fluid.

The two-dimensional immunoelectrophoresis on cellulose acetate, already utilized for serum proteins, has been applied to CSF proteins. The technical modifications which allow the use of unconcentrated CSF are described. By utilizing a particularly suitable supporting medium, a good separation of proteins is achieved; consequently narrow-based peaks are obtained and the isoantigens can be displayed as distinct components in spite of closely similar migration velocities. The preliminary results of this method are given. Particulary interesting appears a beta-migrating protein and the gamma-migrating oligoclonal bands. The first may present an anodic cleavage suggesting that it may be the beta1C/beta1A-globulin. If this hypothesis is confirmed, the relative concentrations of the two components can be investigated. No clear-cut peaks corresponding to the gamma-migrating oligoclonal bands have been observed, their place being taken by a low precipitation line continuous with the IgG peak. The reasons for this phenomenon may be tentatively ascribed to a local specificity of these IgG.

Beta-Globulins↗
PubMed1978

Histochemical and ultrastructural findings in a case of centronuclear myopathy.

A case of centronuclear myopathy is presented. The presence of central nuclei in almost all fibres, the existence of type I fibres only, the histochemical pattern of a negative central zone with a perinuclear halo and a hyperactive rim with oxidative enzymes and the ultrastructural data are discussed in the light of the previous literature. The possible relationships with other myopathies are taken into consideration as well as the fact that central nuclei may be a non-specific change in several conditions. Consequently centronuclear myopathy could turn out to be a syndrome from which different entities can be isolated.

Adenosine Triphosphatases↗