Biomedical subjects

L Soranzo

Publications and source records attributed to L Soranzo.

14 recordsLinked to original sources

PubMed1998

Endocrine and neuroendocrine effects of Azadirachtin in adult females of the earwig Labidura riparia.

In previous studies we have shown that injection of the insect growth regulator Azadirachtin (AZA) into young vitellogenic females induces inhibition of vitellogenesis in a dose-dependent manner. Juvenile hormone treatment rescues vitellogenin synthesis and ovarian growth. The cytopathological effects on ovaries and fat body are not linked to an inhibition of feeding. In this work we investigated the effects of AZA on the endocrine and neuroendocrine system. Enzyme immunoassay reveals that ovarian ecdysteroid levels are drastically reduced, in a dose-dependent fashion, by AZA. Ultrastructural study indicates that corpus allatum cells exhibit signs of inactivity and degenerative changes after AZA exposure. Using an antibody against allastostatin-3 of Blatella germanica (BLAST-3), we show the appearance of strong immunoreactivity of numerous cells and axons in the brain of AZA-injected females. We conclude that vitellogenesis inhibition by AZA consists of a direct cytotoxic effect as well as a generalized disruption of endocrine and neuroendocrine functions.

Animals↗

PubMed1996

[Demonstration of the immunoreactivity of polynuclear eosinophils for bombesin and substance P. A new concept of the neuro-immune axis].

Immunoreactivity for B and SP was detected by means of light and electron microscopy (by preembedding immunocytochemistry), in eosiniphilic polymorphonuclear leukocytes infiltrating the connective tissue of gastrointestinal and respiratory tract in mouse, rat and human ; and in human bronchoalveolar lavages in case of hypereosinophilia. This positive reaction depends on the use of an acetic-acid-containing-fixative (minimum 48 hours), and is located in the granules of eosinophils at their membrane level, and on eosinophil plasma membranes. Eosinophil peroxidases (catalases) should not affect the immunocytochemical reaction, since heating during a paraplast embedding and sodium-azide in electron microscopy procedure destroyed these enzymes. The membrane-bound immunoreaction for B and SP, with very close structural similarity, suggested cross-reactivity between the two neuropeptides, with recognition of one or several epitopes by the polyclonal antisera. One of these epitopes is probably associated with the C-terminal sequence of B (with tachykinin-like activity) and seems to be present in other neuropeptides such as SP ; another epitope would be the N-terminal sequence of SP (with bradykinin-like activity). Hence, eosinophils could be the source of tachykinin and bradykinin. Another hypothesis about the membrane immunolocalization (as yet unproved experimentally) would be a cross-reactivity due to recognition of electron-negative charges of membrane phospholipides. Lysophosphatidic acid could play a hormone-like activity and mimic B and SP activities, such as growth factors. Finally, anti-B and anti-SP antisera could contain anti-idiotype antibodies uncovering receptors. In conclusion : eosinophils might produce neuropeptides or neuropeptide-like substances, with, for instance, bronchoconstrictive activity by paracrine control and possible complementarity with nerve endings.

Animals↗

PubMed1992

Bombesin-like immunoreactivity in eosinophils. A light and electron microscopic study: effect of fixatives and cross-reactivity with various compounds.

Eosinophils immunopositive for bombesin tetradecapeptide were detected by means of light and electron microscopy in human and rat gastrointestinal tract and pulmonary tissue. This immunoreaction was only evidenced after the use of acetic acid-containing fixative such as Bouin's fluid. The dependence of this immunostaining on fixatives and time course were extensively studied. This immunoreaction promotes mainly one epitope probably associated with the C-terminal sequence. This epitope seems also to be present in other neuropeptides such as substance P (SP) and, to a lesser extent in chemotactic factors like formyl peptide (fMLP) or eosinophil chemotactic factor of anaphylaxis (ECF-A). At the electron microscopic level, the immunopositivity was associated with eosinophil membranes.

Animals↗

PubMed1989

Application of Grimelius argyrophil staining to the study of tumour ultrastructure. III. Effects of osmium tetroxide.

The results obtained in electron microscopy for Grimelius (1968) argyrophil staining by the en bloc staining of Vassallo and the staining on section of Håkanson were compared on tumoral and non-tumoral tissue samples and were found to lead to different results. Our earlier results for the en bloc staining method indicated that the fixative used in this process was important and that embedding in resin followed by staining of section weakened silver impregnation. We examined here the effects of OsO4 post-fixation combined with such embedding and found that staining was obtained within a shorter period and was more intense. This staining on section was not specific enough, since it was observed in secretory granules of non-argyrophil cells such as those containing somatostatin. In addition, this staining was not confined to specific peripheral zone as it occurred after en bloc staining; particularly in secretory granules with double structure including a core such as those containing glucagon in the pancreas or certain granules in tumoral carcinoid tissue. Consequently silver deposits were located both in the core and peripheral zone of such granules. Moreover, after OsO4 post-fixation, embedding in resin, and staining on section, argentaffin and argyrophil properties intermingle.

Fixatives↗

PubMed1988

Application of Grimelius argyrophil staining to the study of tumour ultrastructure. II. Effects of resin embedding: Epon.

2 methods have so far been proposed for staining samples by the argyrophil technique of Grimelius for electron microscopy. Vassallo et al. (1971) used en bloc staining after fixation with a mixture of glutaraldehyde and formaldehyde, then Håkanson et al. (1971) stained sections from samples previously fixed by double formaldehyde/OsO4 treatment and embedding in resin. Another investigation that concerned glutaraldehyde fixation showed the effect of this fixative in sample staining (Soranzo and Roland 1987). The present experiments demonstrated that Epon intervenes directly in argyrophil staining of sections. With this resin, the staining process lasted longer than with paraffin embedding materials and offered no guarantee of positivity. Granules with a double structure and dense core displayed different locality of argyrophilia before and after embedding.

Carcinoid Tumor↗

PubMed1987

Application of Grimelius argyrophil staining to the study of tumour ultrastructure. I. Effects of fixatives.

Two methods have so far been proposed for staining samples by the argyrophil technique of Grimelius for electron microscopy. For Håkanson glutaraldehyde prevented argyrophilia, so the author stained sections from samples previously fixed by double formaldehyde/osmium tetroxide treatment and embedding. Vassallo used en bloc staining after fixation with glutaraldehyde-formaldehyde mixtures. We examined each factor which could directly interfere in argyrophil staining en bloc and on section. In the present experiment we compared effects of fixatives after staining en bloc. Glutaraldehyde prevented argyrophilia in 1 case out of 15, that of A-like cells in the oxyntic gland of the rat positivity was maintained in EC-like cells of this gland and adrenalin cells of the adrenal gland contrary to the previous description.

Carcinoid Tumor↗

PubMed1982

[Segmentation of the epididymal duct in mouse: an ultrastructural study].

The cytology of epithelial cells of the mouse epididymis was studied under light and electron microscopy. Four principal areas--the initial segment, the head, the body and the tail--were distinguished according to the morphological features of the main cells. Transitional areas separating these segments have been described also; one of the segments, intermediate between the head and the body, was longer. Five other cell types and their sites were noted: "apical" cells, corresponding to the "narrow" cells of Sun and Flickinger (1980), were located in the initial to the intermediate segment; clear cells were scattered in the epithelium from the intermediate segment to the tail; basal cells were sporadically distributed along the entire duct. Halo and dark cells were observed also.

Animals↗

PubMed1974