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D Liguoro

Publications and source records attributed to D Liguoro.

26 records · Page 2Linked to original sources
PubMed1993

Purinergic (P2) receptor-operated calcium entry into rat thyroid cells.

In the epithelial cell line FRT, derived from rat thyroid, extracellular ATP, at a concentration as low as 1 x 10(-7) M, specifically increases cytosolic Ca++ two fold over the basal level of 255 +/- 45 nM. A maximum increase of 5 fold over basal is seen at 1 x 10(-5) M ATP. The effect occurs in the absence of any measurable phosphatidyl inositol metabolism and requires the presence of extracellular Ca++, but is independent of extracellular Na+; it is duplicated by ATP gamma S but not by adenosine, AMP, ADP, AMP-PNP, AMP-CPP, or AMP-PCP. In the presence of the P2-receptor antagonist suramin, the ATP induced Ca++ influx is completely inhibited, whereas Mg++, La , and verapamil are ineffective. It appears that the most likely (and unique) mechanism of ATP induced increase of cytosolic Ca++ in FRT cells in an increased influx through the activation of a P2 receptor operated Ca++ channel.

Adenine Nucleotides↗
PubMed1993

P2 purinergic agonists and 12-O-tetradecanoylphorbol-13-acetate, as well as protein kinase A activators, stimulate thyroglobulin secretion in FRTL-5 cells.

We studied the role of various intracellular pathways in thyroglobulin secretion. The P2 agonists (ATP, ADP, GTP), 12-O-tetradecanoylphorbol-13-acetate (TPA), and protein kinase A activators stimulate thyroglobulin secretion in cells grown without TSH. The effects of these agents are additive. Pertussis toxin partially inhibits the effect of ATP but has no effect on the action of GTP. ATP and GTP increase cytosolic calcium (279 +/- 16% and 302 +/- 22%, respectively) while TPA and TSH (1 mU/ml) do not. Thus, both the protein kinase A and kinase C pathways regulate thyroglobulin secretion in FRTL-5 cells.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1993

[Transfrontonasal approach: development of a mixed approach to ethmoid tumors. Experience of 12 cases].

Our experience in approaching ethmoid tumors through a combined pathway is currently based on 81 patients. 69 of them were malignant tumors treated by the neurosurgical subfrontal and paralateronasal transfacial rhinological approach. For the past two years, we have adopted the technical modification described in Bordeaux by Pinsolle and San-Galli enabling the approach of the ethmoid bone by means of a unique (Unterberger's scalp) incision and a unical frontonasal flap. 12 patients benefitted from this transfrontofacial access. The advantages and disadvantages of the technique are discussed.

Ethmoid Bone↗
PubMed1992

Modulation of the carbohydrate moiety of thyroglobulin by thyrotropin and calcium in Fisher rat thyroid line-5 cells.

Thyroglobulin secreted in the medium by Fisher rat thyroid line-5 (FRTL-5) cells cultured in the presence of thyroid stimulating hormone (TSH) shows a slower electrophoretic mobility in sodium dodecyl sulfate-polyacrylamide gel electrophoresis and a higher density position in a CsCl gradient than thyroglobulin secreted by FRTL-5 cells cultured in the absence of TSH for 5-7 days. Such a TSH effect is much less or not evident when secreted thyroglobulin is digested with peptide N-glycohydrolase F or when intracellular thyroglobulin is compared. Intracellular thyroglobulin migrates faster than thyroglobulin secreted either in the presence or in the absence of TSH. Evaluation of the mannose and galactose content of thyroglobulin demonstrates that intracellular thyroglobulin has more mannose and less galactose than extracellular thyroglobulin; it also shows that TSH decreases the mannose content of thyroglobulin while increasing its galactose content. Bio-Gel P6 chromatography shows that TSH increases the complex type carbohydrate chains while decreasing the high mannose chains in the secreted thyroglobulin. High mannose type oligosaccharides were characterized by fast atom bombardment-mass spectrometry analysis. Treatment with the calcium ionophore A23187 (5 microM) of FRTL-5 cells cultured with or without TSH causes the appearance of a "fast" migrating form of thyroglobulinin in the culture medium. Bio-Gel P6 chromatography shows that A23187 causes a dramatic decrease of the complex carbohydrate chains of the secreted thyroglobulin.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1992

Anatomical basis of the anterior cervical spine approach: topographic study of the nerve structure.

The results of the surgical anterior approach to the cervical spine are marked in a number of cases by dysphagia and dysphonia, especially when the approach is extensive or performed at the upper cervical spine. 35 cadaver dissections were performed to define the topography of the nerve structures during operative exposure at various vertebral levels: superior and recurrent laryngeal nerves, hypoglossal nerve and its superior root of the ansa cervicalis. The authors suggest some technical improvements, for each stage of surgical dissection.

Aged↗
PubMed1987

Characterization of phosphate residues on thyroglobulin.

Follicular 19 S thyroglobulin (molecular weight 660,000) from rat, human, and bovine thyroid tissues contains approximately 10-12 mol of phosphate/mol of protein. These phosphate residues can be radiolabeled when rat thyroid hemilobes, FRTL-5 rat thyroid cells, or bovine thyroid slices are incubated in vitro with [32P]phosphate. Thus labeled, the [32P]phosphate residues comigrate with unlabeled 19 S follicular thyroglobulin on sucrose gradients and gel filtration columns; are specifically immunoprecipitated by an antibody preparation to rat or bovine thyroglobulin as appropriate; and co-migrate with authentic 19 S thyroglobulin when subjected to analytic or preparative gel electrophoresis. Tunicamycin prevents approximately 50% of the phosphate from being incorporated into FRTL-5 cell thyroglobulin. Approximately one-half of the phosphate in FRTL-5 cell or bovine thyroglobulin can also be released by enzymatic deglycosylation and can be located in Pronase-digested peptides which contain mannose, are endo-beta-N-acetylglucosaminidase H but not neuraminidase-sensitive, and release a dually labeled oligosaccharide containing mannose and phosphate after endo-beta-N-acetylglucosaminidase H digestion. The remainder of the phosphate is in alkali-sensitive phosphoserine residues (3-4/mol of protein) and phosphotyrosine residues (approximately 2/mol of protein). This is evidenced by electrophoresis of acid hydrolysates of 32P-labeled thyroglobulin and by reactivity with antibodies directed against phosphotyrosine residues. The phosphoserine and phosphotyrosine residues do not appear to be randomly located through the thyroglobulin molecule since approximately 75-85% of the phosphotyrosine and phosphoserine residues were recovered in a approximately 15-kDa tryptic peptide or a approximately 24-kDa cyanogen bromide peptide, each almost devoid of carbohydrate. 31P nuclear magnetic resonance studies of bovine thyroglobulin confirm the presence and heterogeneity of the phosphate residues on thyroglobulin preparations.

Animals↗