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F Rosati

Publications and source records attributed to F Rosati.

13 recordsLinked to original sources
PubMed1992

Gas chromatography/mass spectrometry of catechol estrogens.

Catecholestrogens (CCEs), namely 2- or 4-hydroxyestradiol and hydroxyestrone, are highly polar, reactive, and extremely labile estrogen metabolites in many experimental conditions. For these reasons, indirect assay methods mainly have been used. Some experimental evidence suggests that CCEs are synthesized and biologically active mostly in target cells. At this level, unfortunately, the indirect assays cannot be used. We present a method of gas chromatographic/mass spectral (GC/MS) analysis for the identification of individual CCEs; the major fragmentation ions of authentic estrogen standards as trimethylsilylether derivatives, and the MS patterns of the major CCEs, namely, 2-hydroxyestradiol and hydroxyestrone, are included. Few examples of CCEs detected in human breast cancer tissues and in breast cyst fluids are reported. Sample extracts were submitted to reversed-phase, high-performance liquid chromatography (RP-HPLC) and were quantified by "on line" electrochemical (EC) detection; thereafter, either crude extracts or single eluted peaks were submitted to GC/MS, by which detection limits of less than 5 pmol were attained. As expected, the molecular ion was the most relevant molecule in all but one case. On the contrary, the other relative intensities of major fragmentation ions M -15, M -30, M -90, and M -15 + (-90) were unevenly distributed, although represented in the majority of cases. In all cases, the GC/MS of peak fractions, purified by RP-HPLC and UV detection, confirmed the results of liquid chromatographic analysis combined with EC detection. In contrast, GC/MS of crude extracts was not equally satisfactory. Comparison of a liquid chromatography system with EC detection and the GC/MS approach revealed some inconsistency in quantitation of individual CCEs.(ABSTRACT TRUNCATED AT 250 WORDS)

Breast Neoplasms↗
PubMed1991

The vitelline coat spikes: a new peculiar structure of Mytilus galloprovincialis eggs with a role in sperm-egg interaction.

In the course of this study we found that in Mytilus galloprovincialis eggs long filamentous protrusions never described before, which we have termed "vitelline coat spikes," could be clearly detected using the lectin from Dolichos biflorus, which recognizes the GalNAc residues. The spikes could be also observed by transmission electron microscope but only in some fortuitous sections could their origin in the vitelline coat be clearly observed. The spikes were also clearly visible using the scanning electron microscope. Observations of the sperm-egg interaction very few seconds after insemination or using fixed eggs suggested that the spikes could play a role in a primary binding to the unreacted sperm. Experiments have been done to test the effect of GalNAc on the sperm-egg binding and on the fertilization process which seem to confirm this hypothesis.

Acetylglucosamine↗
PubMed1990

Differentiation of the vitelline coat and the polarized site of sperm entrance in the egg of Unio elongatulus (Mollusca, Bivalvia).

We studied the differentiation of the polarized site of sperm entrance in the egg of a freshwater bivalve, Unio elongatulus. As previously shown, in this egg model the property of sperm recognition and binding is restricted to a region characterized by a wrinkled surface which surrounds a truncated cone or crater region, at the vegetal pole of the egg. The crater is formed during oogenesis at a site opposite the oocyte attachment to the ovarian wall. It first appears as a small bleb, and later detaches, leaving in the oocyte an open narrow process filled with an orderly array of microtubules. Here the vitelline coat differentiates from the rest of the oocyte. The role of the microtubules in the formation of the region and the differential distribution of the vitelline coat components is discussed. The synthesis during development of fucosyl containing glycoproteins and their presence in an electrophoretic pattern of isolated vitelline coats were also studied using Lotus tetragonolobus (LTA) conjugated with fluorescein and peroxidase.

Animals↗
PubMed1977

Protein of insect sperm mitochondrial crystals. Crystallomitin.

Mitochondrial derivatives of insect sperm usually contain a crystalline protein that shows a 45-nm main period, made up of 20-nm subperiods, determined by the coiling of filament bundles. Filaments are 2 nm thick and have a globular appearance. The crystals contain two main polypeptides, 52,000 and 55,000 daltons. These polypeptides are closely related, contain a high percentage of proline, and are insoluble in sodium dodecyl sulfate due to disulfide cross links. We suggest for this class of protein the name crystallomitin.

Amino Acids↗
PubMedDate not supplied

Further observations on the morphogenesis of the round headed human spermatozoa.

Sperm and testicular biopsies of an infertile human patient have been investigated using histochemical and electron microscopical technique. Spermiogram revealed a head defect, characterized with lacking acrosome and round and immature nucleoplasm, occuring in practically all cells and coiled tails in about a half of spermatozoa. EM study of spermatids has shown an abortive development of acrosome, whose primordium failed to attach the nucleus and expand, instead regressed. The nucleus failed in shaping and retarded in maturing, a disturbance apparently associated with the aplasia of hypoplasia of caudal manchette. The role of zinc in nuclear differentiation and the shape of head in the movement pattern are discussed.

Acrosome↗
PubMedDate not supplied

Sialyglycoconjugates release during in vitro capacitation of human spermatozoa.

Modifications of the human sperm surface during incubation in capacitating conditions were studied by radiolabeling terminal sialic acid residues of cell surface glycoconjugates using the sodium metaperiodate/sodium tritiated borohydride method. During in vitro capacitation, sialyglycoconjugates were released from the human sperm surface according to well reproducible kinetics. This release could be inhibited by the presence of seminal plasma in the capacitation buffer. Two principal size classes of sialyglycoconjugates were detected in the capacitation medium and analyzed by gel filtration chromatography and SDS-PAGE. The smaller class was characterized by glycopeptides less than 5,000 Da, whereas the larger class was characterized by two sialyglycoproteins of approximately 15,000-16,000 and 22,000-23,000 Mr. The role of human albumin, a key component of the capacitation buffer, in the removal of these molecules from the sperm surface was studied in light of its constant association with large amounts of released material.

Adult↗