Biomedical subjects

M Foti

Publications and source records attributed to M Foti.

41 records · Page 3Linked to original sources

PubMed1993

Ca2+ and Mg2+ regulation of inositol 1,4,5-triphosphate binding in myeloid cells.

Inhibition of inositol 1,4,5-triphosphate (Ins(1,4,5)P3) binding by Ca2+ and Mg2+ remains a controversial issue: the Ca2+ effect may also be explained by Ins(1,4,5)P3 generation due to a Ca(2+)-sensitive phospholipase C, and the Mg2+ effect by Ins(1,4,5)P3 degradation. In this study, we have, therefore, investigated the effects of Ca2+ and Mg2+ on Ins(1,4,5)P3 binding to membranes of the myeloid cell line HL-60 and assayed in parallel phospholipase C activity and Ins(1,4,5)P3 degradation. The assays for Ins(1,4,5)P3 binding, Ins(1,4,5)P3 generation, and Ins(1,4,5)P3 degradation were performed under identical experimental conditions. Ca2+ significantly and reversibly decreased Ins(1,4,5)P3 binding at submicromolar concentrations. Ca2+ stimulated Ins(1,4,5)P3 generation only at concentrations above 1 microM. At 1 microM [Ca2+], Ins(1,4,5)P3 binding was inhibited by 46 +/- 6%, but no Ins(1,4,5)P3 generation was observed. [Mg2+] between 0 and 1 mM slightly stimulated, while higher concentrations inhibited, Ins(1,4,5)P3 binding. Mg2+ did not activate phospholipase C. Neither Ca2+ nor Mg2+ induced relevant Ins(1,4,5)P3 degradation under the conditions of the binding assay. The effects of Ca2+ and Mg2+ on Ins(1,4,5)P3 binding were conserved after solubilization of HL-60 membranes. However, only Mg2+, but not Ca2+, inhibited Ins(1,4,5)P3 binding to the receptor that had been partially purified by heparin affinity chromatography. The Ca2+ sensitivity of Ins(1,4,5)P3 binding to the partially purified receptor could be reconstituted by addition of the flow-through of the heparin column. No Ca(2+)-dependent Ins(1,4,5)P3 generation was observed in the reconstituted system. Thus, we conclude that both Ca2+ and Mg2+ can inhibit Ins(1,4,5)P3 binding independently of phospholipase C activation and Ins(1,4,5)P3 breakdown. The Ca2+ effect depends upon factors that can be separated biochemically from the Ins(1,4,5)P3 receptor. Mg2+ acts either directly on the Ins(1,4,5)P3 receptor or on a closely associated target.

Calcium↗

PubMed1981

In vivo and in vitro interference of phosphatidylserine liposomes on prolactin secretion in the rat.

The effect of sonicated suspensions of phosphatidylserine (PS), an acidic phospholipid, was investigated on prolactin secretion utilizing in vivo and in vitro approaches. Acute and chronic administration of PS reduced plasma prolactin levels during different phases of circadian rhythms. The phospholipid was able to inhibit the plasma prolactin surge, which occurs in cycling female rats on the afternoon of proestrus. The time course of PS on prolactin secretion was characterized by a short latency (15 min) and a long duration of action (6 h). In rats with hypothalamic deafferentation PS partially reduced the increase of circulating prolactin induced by pretreatment with alpha-methyltyrosine. An inhibition of prolactin release was observed if anterior pituitary glands were incubated in presence of PS. This effect was prevented by the addition of the dopamine antagonist sulpiride to the medium. In conclusion, PS decreases prolactin secretion both in vivo and in vitro. The inhibition of the hormone secretion appears to be due to the action of PS at the level of the pituitary; however, a concomitant stimulatory action on the turnover of the tuberoinfundibular neurons cannot be ruled out.

Animals↗

PubMedDate not supplied

[Isolation of S. mbdakada from a child seen at the University of Messina pediatric clinic].

The authors made some diagnostic investigation into a serious case of diarrhoea observed in an infant in the pediatric ward of the University hospital of Messina (Sicily). They brought into evidence some of the causes of the world wide spread of salmonella infection, in particular the spread of new serum-types, such as S. mbandaka, which was involved in this case.

Child, Preschool↗

PubMedDate not supplied

[A new serovar of Salmonella: S. IIIb 35: 1, z13: e, n, x, z15].

The authors describe briefly the protocol for isolating a new serovar of Salmonella from the stools and the sand of a cage-shield of a python (Python regius (Shaw, 1802), kept as pet animal by a family in Messina. Such a finding is considered within the complex and wide investigation programme which we have been carrying out for years in our Institute of Veterinary Infectious Diseases, and within the problems rising from the Health and Hygiene field for the ever increasing diffusion of Enterobacteriaceae, by now limited to the ones collected and belonging to the Genus Salmonella.

Animals↗

PubMedDate not supplied

[Environmental pollution and infectious diseases. I. Isolation of a new serovar of the Salmonella genus, S.V 13.22:r: from a Periplaneta americana cockroach].

The AA have isolated a new serovar of Genus Salmonella S.V 13.22:r:-, from a cockroach Periplaneta Americana, captured near the municipal slaughterhouse of Messina and near the Faculty of Veterinary Science. This fifth original report fift in the vast subject of the environmental pollution, where the cockroaches, as widely documented, unwind a primary importance part as spreader of Salmonella, too.

Animals↗