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Biomedical subjects

M Mazzuca

Publications and source records attributed to M Mazzuca.

At least 73 records · Page 4Linked to original sources
PubMed1977

Limulus polyphemus lectin sites in human bronchial mucosa.

The lectin from Limulus polyphemus (limulin) has an affinity for glycoproteins containing N-glycolyl or N-acetylneuraminic residues. By using a peroxidase labeled limulin on human bronchial mucosa sections, it has been possible to demonstrate selectively a diffuse staining within the apical part of the epithelial goblet cells. Whereas, in the submucosal glands serous cells, the labeling appears as small granules localized either at the apical pole or in the whole cytoplasm. In our experimental conditions the labeled limulin has no affinity for mucous cells that are known to contain sialic acid residues.

Arthropods↗
PubMed1976

The thyrotropic cells of the guinea pig pituitary. Electron microscopic study after characterization by immunocytochemical means.

Three different immunocytoenzymatic techniques were used to identify and characterize the thyrotropic cells in the pituitary of normal guinea pigs at the ultrastructural level (superimposition technique, immunocytochemical technique using P.A.P. and indirect immunohistoenzymatic method before embedding). These cells are characterized by a dark cytoplasm with granules ranging from 1500 to 2000 A in diameter. The appearance of these granules is very variable: some display a marked electron density and are homogeneous but some have a less marked electron density with a more electron dense peripherally situated region. The TSH molecules are essentially confined to the granules but when the immunocytochemical reactions are carried out before embedding, positive staining is also seen in the cytoplasm and the outer surface of most of the rough endoplasmic reticulum membranes. These results are discussed.

Animals↗
PubMedDate not supplied

[Dissociation of results obtained with an immunofluorescence technique by using anti-ACTH antibodies in three cases of pituitary "chromophobe" adenoma without hypercorticism; ultrastructural study (author's transl)].

Morphological studies of 3 pituitary "chromophobe" adenoma in patients without hypercorticism show positive immunofluorescenct cells with anti alpha, 17-39 ACTH antibody which are not revealed with anti beta, 1-24 ACTH antibody. These cells observed at the ultrastructural level contain secretory granules of 1,000 to 1,500 A in diameter. The existence in these cells of a substance having an immunological relationship with ACTH without biological activity is discussed.

Adenoma, Chromophobe↗
PubMedDate not supplied

Dystrophic neuropeptidergic neurites in senile plaques of Alzheimer's disease precede formation of paired helical filaments.

The relationship between peptidergic neurites and paired helical filaments (PHF)-positive neurites in Alzheimer's disease (AD) senile plaques (SP) was studied using combined fluorescence and bright field optics. Cryostat sections of AD hippocampi were first stained by thioflavine-S and immunolabeled with antisera raised against different neuropeptides: somatostatin 28(1-12) (som 28(1-12)), somatostatin 14 (som 14), neuropeptide Y (NPY), cholecystokinin (CCK) and substance P (sP). Secondly, using the elution-restaining procedure, sections were immunolabeled with anti-tau/PHF. In immature SP, clusters of abnormal, swollen neurites were found. The dystrophic, strongly peptidic-positive neurites contained less PHF than the poorly positive ones. Cell bodies, exhibiting a peptidic content, could be found within SP without any alteration. These results suggest the following sequence of events: an extracellular poisoning mechanism, perhaps the amyloid substance, first changes the structure of presynaptic endings and causes the formation of ballooning dystrophic neurites filled with their normal peptidic content. Subsequently, intracellular degradation occurs with formation of the PHF. Then the other structures such as dendrites and perikarya are damaged by the same mechanism. Therefore this phenomenon seems to precede any formation of PHF in SP.

Alzheimer Disease↗
PubMedDate not supplied

[Study of mucins of two sinus mucoceles (author's transl)].

Glycoproteins were isolated in the contents of two sinus mucoceles by ionic exchange and gel filtration chromatography. These glycoproteins are of the mucin-type and characterized by their richness in carbohydrate, a low amino acid content with a strong proportion of hydroxy amino acids. However, they differ largely by their peptide axis, the length of the carbohydrate chain and their acidity, which is in relation with the presence of sialic acid residue and of sulfate groups. The least acidic mucins are the richest in sialic acid residue and in threonine but have the shortest carbohydrate chains while the most acidic are rich in sulfate, richer in serine and have longer carbohydrate chains. The wall of these two mucoceles has only one type of cell capable of synthetizing the glycoproteins: the epithelium goblet cells revealed by the PAS and the alcian blue at different pH. Glandular formations have never been found in the chorion.

Amino Acids↗