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Biomedical subjects

F Ciani

Publications and source records attributed to F Ciani.

At least 73 records · Page 4Linked to original sources
PubMed1983

Impermeability of newt cerebral and pial capillaries to exogenous peroxidase. A light and electron microscope study.

The permeability of cerebral vessels to exogenous peroxidase was studied in the newt. The reaction product was found only inside the cerebral or pial blood vessels. Electron microscope investigations revealed the presence of reaction product along the luminal area of vessels and in some parts of the intercellular spaces at the level of tight junctions joining endothelial cells. On the basis of the ultrastructural peroxidase localization, the presence of a brain-blood barrier in Triturus is discussed.

Animals↗
PubMed1982

Acetylcholinesterase activity of the mesencephalic trigeminal nucleus of Triturus cristatus carnifex.

This study deals with acetylcholinesterase activity in mesencephalic trigeminal nucleus neurons of the newt. These cells appear clearly positive to histochemical reaction. Electron microscope investigations revealed the fine localization of the enzyme in cell bodies. On the basis of the ultrastructural pattern of AChE distribution some considerations on the possible sites of utilization are discussed.

Acetylcholinesterase↗
PubMed1982

Acetylcholinesterase reappearance in the early reparative process in the optic tectum of newt. An electron microscopic study.

AChE distribution during the early phases of the repairing process following the removal of a plug from the optic tectum of newt has been investigated. The first AChE-positive neurons appear in the regenerating area on the 60th day after the operation. At this stage acetylcholinesterase activity is clearly seen also between the nervous fibers and in some large dendrites, present in the superficial fibrous area. The enzyme distribution and the submicroscopic organization show that in this area cholinergic connections between regenerated axons and newly-formed nervous elements are being established.

Acetylcholinesterase↗
PubMed1982

The pattern of acetylcholinesterase distribution in the normal and retino-deprived optic tectum of newt.

A light and electron microscopic histochemical study has been carried out on the localization of acetylcholinesterase in the optic tectum of newt. The ultrastructural analysis reveals that the pyriform neurons in the periventricular area are provided with the metabolic pathways for AChE synthesis. The enzyme, synthetized in the rough reticulum and conveyed in dendritic branches is prevailingly released in two reaction bands in the neuropil of the superficial fibrous zone. The ablation of one eye gives rise to both the degeneration of retinal tracts and terminals and to the disappearance of the most external reaction band. Some modifications in AChE distribution are also evident in the only reaction band therein. The results obtained are interpreted on the basis of some hypotheses about possible cholinergic mechanisms being active in the optic tectum of Urodela.

Acetylcholinesterase↗
PubMed1981

Biogenic amine terminals in the goldfish cerebellum and optic tectum: a fluorescence and autoradiographic study.

The intraventricular administration of 3H-noradrenaline was used to demonstrate the presence and the distribution of the monoaminergic terminals in the goldfish cerebellum and optic tectum. Monoaminergic terminal can be selectively labelled by tritiated neurotransmitter and are visualized by light and electron microscopic autoradiography. Further evidence of the presence of catecholamines in these encephalic areas was furnished by the induced-fluorescence technique.

Animals↗
PubMed1979

Ultrastructural localization of acetylcholinesterase in retino-deprived optic tectum of the goldfish.

The ultrastructural localization of AChE has been studied in the optic tectum of the goldfish after unilateral eye ablation. 1 or 4 months after the operation the patterns of enzyme localization were essentially the same in the normal and affected optic tectum, despite structural modifications caused by the degeneration of retinal terminals and dendritic atrophy of some tectal neurons. The results are discussed in relation to the different hypotheses put forward concerning possible cholinergic mechanisms in the optic tectum of teleosts.

Acetylcholinesterase↗
PubMed1979

Electron microscope histochemistry of acetylcholinesterase distribution in the optic tectum of teleosts.

An ultrastructural analysis was made on acetylcholinesterase (AChE) localization in the optic tectum of two teleosts, the goldfish and the catfish. Electron microscope histochemistry reveals several details on synthesis, distribution and possible sites of utilization of the enzyme in the different tectal layers. The results show that AChE is synthesized by all the neuronal types present in the optic tectum. The final localization of the enzyme is the result of its synthesis in cell bodies, its storage and transport along dendrites and its release in extracellular spaces. The differences in AChE localization between the two teleosts examined mainly derive from differential enzyme release in the corresponding layers of the optic tectum. Cholinergic synapses cannot be precisely identified by means of AChE histochemistry, but the layers in which maximum release of enzyme in the extracellular spaces occurs most likely correspond to areas where cholinergic mechanisms are operating. In this connection some interesting differences of AChE localization in the superficial tectal layers (stratum marginale, stratum opticum and stratum fibrosum et griseum superficiale) are discussed. Electron microscopic histochemistry of AChE confirms its usefulness in better understanding some links between the anatomical and functional organization of complex neural structures.

Acetylcholinesterase↗
PubMed1978

Acetylcholinesterase activity in the normal and retino-deprived optic tectum of the quail. Light and electron microscopic histochemistry and biochemical determination.

Acetylcholinesterase localization has been studied by electron microscopic histochemistry in the quail optic tectum. Ultrastructural analysis reveals that the different neuronal types in the tectum possess the metabolic pathways for AChE synthesis to different degrees. From the site of synthesis in cell bodies the enzyme spreads towards areas of neuropil. In the neuropil of AChE-rich areas a balance seems to exist between enzyme stored in dendrites (and sometimes axon terminals) and enzyme released into the extracellular spaces. Precise identification of cholinergic synapses by means of AChE localization is in most cases impossible, due to extensive spread of the enzyme through the extracellular compartments of the neuropil. Unilateral ocular ablation causes disappearance of the stratum opticum and decrease in thickness of the superficial tectal layers in the contralateral optic tectum, but only minor modifications in AChE localization. This finding is in agreement with biochemical results which show equivalence of the relative concentration of AChE in the right and left optic tectum 1 or 2 months after ablation of the right eye. The experimental evidence suggests that cholinergic mechanisms are not related to the discharge of retinal afferents on receptive tectal neurons, but more likely to intrinsic neural circuits which might be involved in the modulation of tectal activity.

Acetylcholinesterase↗
PubMed1977

Ultastructural analysis on acetylcholinesterase localization in the cerebellar cortex of teleosts.

The histochemical localization of acetylcholinesterase (AChE) was studied by electron microscopy in the cerebellar cortex of the goldfish and the catfish. The patterns of enzyme distribution show noticeable differences in the two teleost species at the level of the corresponding cerebellar structures. Among the most distinctive features is the prevailing intracellular localization of enzyme activity in the goldfish and the prevailing extracellular localization in the catfish in the molecular layer and, to a lesser extent, the granular layer. Only quantitative differences in the ability to synthesize AChE can be recorded among the different cerebellar neurons in the two species, since all these neurons exhibit different amounts of enzyme activity linked to their cytoplasmic structures. Comparing the results obtained with those of previous histochemical, experimental and developmental researches, the hypothesis seems well founded that the embryonic pool of cerebellar neurons is made up of AChE-synthesizing nruroblasts which, during development, loss or maintain to a different the mechanisms for AChE synthesis. In addition the light and electron microscope histochemistry reveals at different levels of resolution that the final pattern of AChE distribution in the cerebellar cortex is the sum of different degress of AChE synthesis by cerebellar neurons and different degrees of enzyme release in extracellular spaces.

Acetylcholinesterase↗
PubMed1977

Ultrastructural pattern of acetylcholinesterase distribution in the cerebellar cortex of the quail.

The ultrastructural localization of acetylcholinesterase (AChE) was studied in the cerebellar cortex of the quail by means of histochemical method. The greater amount of AChE was detected at leve of the molecular layer in the intracellular spaces between parallel fibers and between parallel fibers and dendritic terminals. Many neurons showed intracellular localization of enzyme activity: the AChE positive neurons were all Golgi cells, most stellate the basket cells and different aliquots of Purkinje and granule cells. The enzymatic activity was usually localized in the cisternae of endoplasmic reticulum, in the nuclear envelope (but this last localization was not present in Purkinje cells- and sometimes in the Golgi apparatus; reaction granules were usually scarce in the different dendritic branches ramifying in the molecular layer. On the basis of the ultrastructural pattern of AChE distribution, some considerations are developed on the methodological aspects concerning the reliability of histochemical methods, the differences recorded at light and electron microscope level, the problems related to extracellular localization of enzyme, the difficulty of establishing a precise correlation between AChE localization in a cerebellar neuron and its possible cholinergic and/or cholinoceptive nature.

Acetylcholinesterase↗
PubMed1976

The fine localization of ATPases in cultures in vitro of chick embryo spinal cord.

A histochemical study of the ultrastructural localization of ATPases in cultures of chick embryo spinal cord has been carried out. The localization of Ca2+ and Mg2+ activated membrane ATPases appears similar: both enzyme activities are localized on the outer surfaces of plasma membranes of all kinds of cell present in the cultures, with the exception of the membranes in direct contact with the culture medium. The results are discussed in relation to data concerning the localization and function of ATPases in vivo and in relation to the possible establishment of mechanisms of nutrient uptake and transfer in cultures of nervous tissue.

Adenosine Triphosphatases↗
PubMed1976

Immunochemical studies on carcinoembryonic antigen-reactive glycoproteins from carcinomas of the colon and breast separated by concanavalin A affinity chromatography.

Analysis of carcinoembryonic antigen (CE)-reactive glycoproteins from liver metastasis of primary colon and breast tumors and from primary breast tumors has been carried out by affinity chromatography on concanavalin A (Con A)-Sepharose. Three CEA-reactive glycoproteins from colon tumors (liver metastasis) with different binding capacity to Con A have been separated and further purified by gel filtration. Of the 3 CEA-reactive glycoproteins, 1 of them did not bind to Con A. Both Con A-binding and nonbinding CEA-reactive glycoproteins were immunologically indistinguishable when tested with a reference goat anti-CEA (ACE, 67-70; Dr. C.W. Todd and Dr. M.L. Egan), as well as with a variety of rabbit anti-CEA and anti-CEA (nonbinding) prepared in this laboratory. Carbohydrate analysis showed that mannose content of different purified CEA preparations or nonbinding CEA did not differ appreciably. N-Acetylglucosamine content of purified CEA preparations, however, varied considerably, suggesting that this sugar may impart the specificity of binding of CEA to Con A. The purified CEA preparations differed in their ability to inhibit the binding of 125l-labeled CEA to goat anti-CEA. One of the purified CEA preparations had 3- to 8-fold greater inhibitory capacity when compared to other preparations and shared a partial identity with a glycoprotein present in the extracts of fetal colon. The glycoprotein extracts of primary breast tumors did not contain a CEA that was immunologically identical to CEA present in colon tumors, whereas the liver metastasis of primary breast tumors showed several CEA-reactive glycoproteins as judged by radioimmunoassay. However, these CEA-reactive glycoproteins did not have any antigenic relationship with CEA from colon tumors when tested by double diffusion and immunoelectrophoresis. In conclusion, when Con A affinity chromatography of tumor glycoproteins is carried out under defined conditions and with the use of appropriate antisera, it is possible to delineate the presence or absence of CEA in tumors of nonentodermal origin.

Carcinoembryonic Antigen↗