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Biomedical subjects

L Medolago-Albani

Publications and source records attributed to L Medolago-Albani.

At least 19 recordsLinked to original sources
PubMed1992

Morphometric analysis of Mauthner axon cytoskeletal components in adult and subadult fish.

A previous cytoskeletal analysis on trout MA during developmental stages demonstrated, during the subadult stages, neurofilaments (NF) as main components as expressed by the high values of neurofilament to microtubules (MT) ratio which was found to be of the order of 300:1. Since the MA cytoskeletal composition is not known in the adult fish, the MA cytoskeletal composition has been compared to other axons of much smaller diameter of the fasciculus longitudinalis medialis (flm) among which the MA run in the ventral spinal cord. The following parameters were measured on conventional electron microscopy in MA and flm axons cross sections micrographs by means of a computer linked graphic tablet (Apple II): axonal caliber, number of microtubules (MT), microtubular (MT/microns2) and neurofilament (NF/microns2) densities. The analysis of these parameters demonstrated that neurofilaments are the main architectural components in the adult and subadult fish MA and flm axons. However, MA cytoskeletal composition differs from the other flm axons because of its particular very high ratio of neurofilaments to microtubules. The inverse relationship of axonal caliber to microtubular density, previously found in the trout during developmental stages and suggested also for many other vertebrate species, was further confirmed for flm axons which, with calibers 10 times smaller than MA, exhibit a microtubular density 10 times larger.

Animals↗
PubMed1986

The response of ventral horn neurons to ricin. An experimental abiotrophy model.

The morphological alterations of anterior horn neurons of the spinal cord of rabbits produced by the administration of ricin conveyed via retrograde axonal flow are described. The differences with the primary response after axonal transection and the similarity with degenerative abiotrophic systemic lesions are discussed.

Animals↗
PubMed1986

Preliminary histochemical and electron microscopic observations on the nervous system of hydra.

The nervous system of a primitive Coelenterate (Chlorohydra viridissima) has been studied using ultrastructural and histochemical techniques. The authors confirm the ultrastructural pattern of nerve cells described by Lentz and coworkers. Reserpine treatment fails to induce any reduction of catechol- and indoleamine content visible to histochemical observation. In vivo treatment with tetanus toxin does not induce behavioural changes and no specific binding of toxin is revealed by immunocytological analysis. This suggests that neuron tetanus toxin receptor sites are absent in hydra. Hydra nerve cells must therefore be considered as extremely primitive elements, which the Authors consider to support the hypothesis of neurons having originated as a gradual differentiation of myoepithelial cells, as proposed by Pantin (1956) and by Passano (1963).

Animals↗
PubMed1983

Electron-microscopic visualization of binding of antibodies from sera of glioma patients on cultured glioma cells.

Several human cell lines (normal and neoplastic glia, cerebral metastases from adenocarcinoma, fibroblasts) were incubated with sera from patients with well and poorly differentiated glioma and with sera from healthy donors and then stained with PAP complex to define and localize the antibody reaction with cell surface antigens by means of electron microscopy. The sera of glioma patients proved to contain antibodies which bound the tumor-associated antigenic determinants on the cell membranes of gliomas and of cerebral metastases from adenocarcinoma in tissue cultures. Further, absorption testing of the reactive sera on normal brain, well-differentiated astrocytoma and cultured glioblastoma cells, together with cross-reactivity experiments suggests that at least two antigens or groups of antigens are expressed on the glioma cell surface: one shared by well and poorly differentiated glioma cells and the other by poorly differentiated glioma cells and the cells of cerebral metastases from adenocarcinoma.

Antibodies↗
PubMed1983

The cerebrum of Dugesia gonocephala s.1. Platyhelminthes, Turbellaria, Tricladida. Morphological and functional observations.

Investigation of the cerebrum of Dugesia gonocephala s.1. using modern techniques has shown that the neurons of these animals situated at the bottom of the phylogenetic scale are basically the same as those of Vertebrates from the ultrastructural and molecular standpoints (tetanus toxin binding). There is no evidence of any biochemical glio-neuronal relationship, nor do the so-called supporting cells appear similar to the glial cells of the higher Vertebrates from this point of view.

Animals↗
PubMed1981

Photosensitization and the nervous system in the planarian Dugesia gonocephala. A histochemical, ultrastructural and behavioral investigation.

Photosensitization phenomena may be induced in planarias by eosin and hematoporphyrin, and as a result, dopamine agonistic behavior ("screw-like hyperkinesia") is set up in the animal. Histochemical, ultrastructural and pharmacological investigations have shown that this hyperkinesia is of post-synaptic origin in eosin photosensitization, and of pre-synaptic origin in hematoporphyrin photosensitization. The authors suggest an hypothesis to explain the different activity of the two photosensitizers, and discuss the validity of the experiment with regard to human porphyria.

Animals↗
PubMed1979

The pigmentary system of planaria. I. Morphology.

The pigmentary system of the planaria, Dugesia gonocephala s.l. (Platyhelminthes, Turbellaria, Tricladida), has been studied by light and electron microscopy. The system consists of granules contained in chromatophore-like cells embedded in the parenchyma. The cell processes penetrate between the muscle layers and extend to the sub-epidermal basal lamina. The nature of the pigment and the comparative anatomical significance of the chromatophore structure is discussed.

Animals↗
PubMed1979

The pigmentary system of planaria. II. Physiology and functional morphology.

The pigmentary system of the planaria, Dugesia gonocephala s.l. (Platyhelminthes, Turbellaria, Tricladida), consists of granules contained in chromatophore cells distributed in the parenchyma tissue. The administration of MSH release-inhibiting Factor (M.I.F.) leads to an easily observable general decolouration of the animal due to the migration of the pigment granules towards the deeper-lying cell nucleus. In planarians bisected transversely through the pharyngeal region, the decolouration occurs only in the cephalic segment, and the caudal segment remains dark. When, however, the decapitated caudal segment regenerates a head region, a decolouration response occurs when exposed to M.I.F. The significance of these results is discussed, and an hypothesis on the hormonal regulation of the pigmentary system is proposed.

Animals↗
PubMed1977

[Copper and nervous system. An experimental study (author's transl)].

Sodium azide is known to produce alterations in mammalian copper proteins, thus rendering them unable to bind exogenous metal, which remains in the "labile pool" condition. Continuous administration of sodium azide at LD50 for 30 days causes copper accumulation in several tissues and even in the nervous system, with characteristic changes in neurones and glial cells, very much resembling the alterations observed in Wilson's disease. Dietary copper administration, on the contrary, though raising the level of tissue-bound metal, does not produce cellular damage. These findings allow us to suppose that sodium azide may alterate the coppper chelating proteins in the tissues, especially in the nervous system, thus causing the storage of cell-toxic "labile pool" metal. The pathogenesis of Wilson's disease and the problem of "pathoclisis" in the nervous system are debated.

Animals↗
PubMed1976

Ultrastructural changes in human leukemic cell nuclei.

The ultrastructural changes of human leukemic cell nuclei have been investigated. Particular attention is paid to the alteration of the nuclear envelope and its constituents, i.e., the pores and the Zonula Nucleum Limitans which appear constantly involved in these pathologic processes. An alteration of the relationship between the components of the nuclear envelope and the chromatin itself may be responsible for the appearance of the most nuclear changes.

Cell Nucleus↗
PubMed1976

Ultrastructural hypoxic changes in Ammon's horn and Purkinje cells.

Guinea pigs were exposed for varying periods to different degrees of hypoxia by respiration of controlled mixtures of O2-N2 and the CNS subjected to both light and electron microscopic examination after aldehyde fixation by perfusion. The subacute anoxia experiments revealed an alteration in the rough endoplasmic reticulum of the Purkinje cells consisting of the formation of 'paired cisternae'. In the chronic anoxia experiments, small ultrastructural alterations of the same cells were found in association with the appearance of monoparticulate glycogen. The authors debate the significance of these ultrastructural alterations in relation to the damage found in other organs.

Animals↗