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Biomedical subjects

F Marangoni

Publications and source records attributed to F Marangoni.

48 records · Page 3Linked to original sources
PubMed1992

Increments of dietary linoleate raise liver arachidonate, but markedly reduce heart n-6 and n-3 fatty acids in the rat.

Four diets containing 20% of energy (en%) as fat and with linoleic acid contents of 1.9, 3.1, 7.7 and 10.1 en%, respectively, were fed to one-month-old male rats for three months. The fatty acid profiles and the levels of the major n-6 and n-3 fatty acids in the lipids of plasma, liver, heart and kidney were measured. We found that with increasing concentrations of 18:2n-6 in the diet, linoleic acid rose in plasma and in all organs, but long-chain n-6 and n-3 fatty acids responded differently. In liver, arachidonic acid increased and n-3 fatty acids were not significantly affected; in heart, both arachidonic and docosahexaenoic acids were progressively reduced; and in kidney, there was no change of n-6 and n-3. The results indicate that incremental changes in dietary linoleate affect the levels of polyunsaturated fatty acids in liver and extrahepatic organs differently.

Animals↗
PubMed1992

Olive oil, corn oil, and n-3 fatty acids differently affect lipids, lipoproteins, platelets, and superoxide formation in type II hypercholesterolemia.

To evaluate which dietary fat may provide the best response in terms of plasma lipids and lipoproteins and also of platelet aggregability and superoxide formation by white blood cells, 12 type II patients were randomly allocated to three different diets, which provided polyunsaturated fatty acids (corn oil), monounsaturated fatty acids (olive oil), and a supplementation of ethyl esters of n-3 fatty acids to a prudent diet. Olive oil and, more significantly, n-3 ethyl esters lowered total cholesterol best (-2.2% and -5.8%, respectively); the latter diet, as expected, also significantly lowered triglyceridemia (-21.4%). The corn-oil diet exerted a small, statistically significant reduction of high-density-lipoprotein cholesterol (HDL) (-4.3%), and it also lowered plasma total apo B concentrations (-3.8%). n-3 ethyl esters significantly raised both total (+3.1%) and particularly HDL2 cholesterol (+24%). Platelet reactivity was insignificantly reduced by the three regimens, but all three significantly reduced thrombin-stimulated formation of thromboxane B2. Finally, only the n-3 fatty acid supplementation significantly reduced O2- generation by adherent monocytes. Dietary unsaturated fatty acids are generally effective on the plasma lipid and lipoproteins in type II patients, but significant differences may be found between the three tested regimens.

Apolipoproteins↗
PubMed1992

Immunoglobulin classes and subclasses of platelet antibodies in a case of post-transfusion purpura.

A multiparous white woman developed severe thrombocytopenia following transfusion of red blood cells. Six ineffective platelet transfusions (a total of 42 random donor concentrates) were given from day 0 to day +6, high-dose steroids from day +1, progressively tapered until day +30, and a total of 150 g of intravenous immunoglobulins from day +2 to day +6. As platelet count had not increased significantly by day +8, four plasma exchange procedures, each consisting of 2,000 ml of plasma exchanged with 5% albumin solution, were performed on days +8, +10, +14 and +18. Platelet count was 5, 50, 100 and 234 x 10(9)/l on days +8, +14, +26 and +32 (discharge), respectively. The patient's acute phase serum contained increased levels of platelet alloantibodies with anti-HPA-1a (PlA1, Zwa) specificity and a titer of 3,200. IgG1, IgG2 and IgG3 subclasses of platelet-reactive antibodies in the patient's serum were elevated, whereas IgG4, IgM and IgA were within the reference values. Levels of IgG1, IgG2 and IgG3 of antiplatelet antibodies showed a marked and parallel reduction during treatment, but were still above the reference values at the end of treatment and 1 year later, when the patient platelet count was normal. Although a failure of intravenous immunoglobulins cannot be proven in this case, plasma exchange seems to have contributed more than intravenous immunoglobulins to clinical remission.

Aged↗
PubMed1992

Plasma lipids and fatty acid levels in chronically uremic patients undergoing blood purification with different methods.

Levels of plasma lipids and the fatty acid composition of major plasma lipid classes have been determined in chronically uremic patients before and after treatments with hemofiltration, high efficiency paired filtration dialysis, or acetate-free biofiltration. The major findings are a decrease of triglycerides and an increase of total free fatty acids (FFAs) at the end of the dialytic session--already reported in the literature--that do not appear to be strictly dependent on heparin administration. The changes in the plasma concentrations of selected saturated and polyunsaturated fatty acids, which may contribute to alteration of functional parameters in the cardiovascular system in dialyzed patients, are different in the various types of techniques.

Adult↗
PubMed1992

Platelet concentrates stored in synthetic medium after filtration.

Platelet concentrates prepared from pooled buffy coats (BCPC) were stored in Plasma-Lyte A, a glucose-free synthetic medium, after leukocyte depletion by filtration through Pall PL 50, and compared to paired unfiltered BCPC stored in the same medium. Each pair of BCPC units was prepared from a pool of 10 buffy coats split into two identical units. Platelet and leukocyte counts per unit of BCPC were 2.70 +/- 0.19 x 10(11) and 3.8 +/- 2.8 x 10(6) (filtered BCPC), 2.59 +/- 0.27 x 10(11) and 79 +/- 56 x 10(6) (control BCPC), respectively. Filtration procedures did not affect in vitro parameters of platelet quality and function such as osmotic reversal, ATP release and aggregation in response to collagen and ADP during 15-day storage. A similar decrease of platelet membrane glycoprotein Ib and a similar rise of activation markers GMP-140, gp 53 and platelet-bound fibrinogen were observed during storage of filtered and control BCPC. Our study indicates that storage of BCPC after filtration is feasible and that a reduction in leukocyte content by filtration to mean cell counts of less than five millions per unit has probably no effect on platelet storage lesion.

Adenosine Diphosphate↗
PubMed1991

Vascular eicosanoids and platelet-aortic wall interactions in spontaneously hypertensive rats.

We studied the aggregation of collagen and ADP-stimulated platelet-rich plasma (PRP) and the formation of thromboxane B2 (TxB2) by collagen-stimulated PRP in spontaneously hypertensive rats (SHR) and in Wistar-Kyoto control rats (WKY). In addition, we evaluated the inhibition of the aggregation of PRP following homologous or heterologous perfusions through isolated aortas, the release of 6-keto-prostaglandin (PG)F1 alpha from these arteries perfused with PRP, and the sensitivity of PRP to the antiaggregatory activity of the stable PGI2 analogue, iloprost, in both SHR and WKY. The lower activities (aggregation induced by ADP and collagen, collagen-stimulated TxB2 production) of SHR platelets, were not accompanied by morphological differences from WKY platelets. These changes were associated with a greater release of arterial 6-keto-PGF1 alpha, with greater platelet antiaggregatory activity of the arterial wall and with higher sensitivity of platelets to iloprost. The lower reactivity of platelets to aggregating agents, and the greater sensitivity to prostacyclin, associated with a greater production of arterial prostacyclin were the major changes observed in SHR animals. These alterations in the SHR vs. normotensive WKY may lead to an enhanced risk of hemorrhage in the hypertensive state.

6-Ketoprostaglandin F1 alpha↗
PubMed1985

Determination of cefatrizine levels in blood, tonsils, paranasal sinuses and middle ear.

Levels of cefatrizine, a new oral cephalosporin, were determined in blood and in tonsils, paranasal sinus secretions and middle ear exudates from 18 patients with acute infections at these sites. Three and six hours after administration of 500 mg cefatrizine satisfactory levels of the antibiotic were found at all the sites examined. Levels in the tonsils and middle ear were higher than those in blood, while lower levels were recorded in nasal secretions.

Bacterial Infections↗
PubMedDate not supplied

Recent advances in the biology of n-6 fatty acids.

The intensive research carried out in the last 10 years on the unique biological functions of n-3 fatty acids (FA), has promoted comparative investigations on various aspects (metabolic, functional) of the biology of n-6 FA. The involvement of peroxisomes in fatty acid metabolism, initially described for the n-3 acids, has now been shown also for the n-6 FA (formation of 22 carbon delta 4 unsaturated FA, formation of newly identified products of beta-oxidation of arachidonic acid, AA). Additional pathways of AA conversion, beyond the classical eicosanoids, give rise to a series of biologically active products, such as the epoxides, involved in the modulation of vascular functions, through the cytochrome p450 system, and to the AA-ethanolamide, anandamide, an endogenous ligand of the cannabinoid receptors, through a phospholipase-mediated process. Finally, nonenzymatic oxidation products of AA, the isoprostanes, isomers of prostaglandins, also endowed of potent biological activities, are generated both in in vitro-induced lipid oxidation and in vivo, being considered as reliable markers of in vivo oxidative stress. As to the nutritional aspects of the n-6 FA, attention is now paid to the intake of preformed long-chain polyunsaturated FA (PUFA) in the n-6 series, mainly AA, through the diet, in analogy with the intake of the long-chain n-3 FA, in fish-eating populations. The importance of the dietary intake of preformed AA is now recognized in newborns, through maternal milk. The ranges of the intakes of AA in population groups, not currently adequately estimated, appear to be wider than generally assumed, and the elevated intakes in some population groups, in the order of several hundred milligrams per day, may be partly responsible of yet unexplored population-based differences in physiologic variables. Recent research on the functional effects of n-6 FA has confirmed their lipid-lowering effects, which can be observed also in neonates, and has shown that, in cooperation with the n-3, they directly and indirectly contribute to modulate functional parameters at the cellular level, such as receptor function, ion channels, and gene expression. From a nutritional point of view, it is clear that PUFA represent the biologically most active component of dietary fat, and the n-6 are quantitatively the most relevant fraction in our diet. In the light of the diversified activities of n-6 and n-3 PUFA, a correct balance between the various fatty acids is recommended.

Adult↗
PubMedDate not supplied

Polyunsaturated fatty acids in maternal plasma and in breast milk.

In order to explain processes underlying the transfer of fatty acids from the maternal compartment into human milk, the lipid content and the fatty acid composition of maternal plasma and milk have been analyzed in breastfeeding mothers at 1 day and 3 months of lactation. The rise in milk lipids occurring during the study period was concomitant with a fall in plasma total fat content, mainly due to the decrease of triglycerides. Significant correlations between plasma and milk fatty acids at the two time points were observed only for linoleic (LA, 18:2 n-6) and (alpha;-linolenic acid (alpha LNA, 18:3 n-3), while for arachidonic (AA, 20:4 n-6) and docosahexaenoic acid (DHA, 22:6 n-3) correlations were found only at one day and 3 months, respectively. These data suggest that levels of the n-6 and n-3 18C polyunsaturated fatty acids in milk are closely dependent on their concentrations in maternal plasma, in turn related with the dietary intake, while the accumulation of AA and DHA in milk is the result of a sequence of transfer and metabolic processes.

Adult↗
PubMedDate not supplied

Regulation of PUFA metabolism: pharmacological and toxicological aspects.

Levels of the long-chain polyunsaturated fatty acids (LCP) of the n-6 and n-3 series in animal plasma and cells are directly or indirectly dependent upon the intakes of either their precursors, the short-chain polyunsaturated fatty acids (SCP), linoleic (LA, 18:2 n-6) and alpha linolenic acid (ALA, 18:3 n-3), respectively, and/or of the preformed products (arachidonic, 20:4 n-6) and eicosapentaenoic acid (EPA, 20:5 n-3) and docosahexaenoic acid (DHA, 22:6 n-3). We report here that pharmacological agents and cytotoxic compounds significantly affect the production of LCP from SCP in cultured cells. Using labelled substrates and radio HPLC separations, we observed that the potent hypocholesterolemic agent, simvastatin, activates the formation of AA from LA, mainly acting at the delta5 desaturation step, and increases also the mRNA levels, in cultured monocytic cells (THP-1). Elevation of AA occurs also in plasma lipids of hyperlipemic patients treated with statins (but not with fibrates). Conversely, oxysterols (mainly 7-beta-oxysterol), which are detected in circulating lipoproteins of rabbits on a hypercholesterolemic diet, potently inhibit the synthesis of AA from LA in hepatocytic cell lines (Hep-G2). At the same time plasma levels o AA are reduced vs controls, in spite of an identical intake of LA. Finally, on the basis of previous work showing reduced levels of LCP, mainly DHA, in the milk of cigarette-smoking mothers, we have observed that the incubation of human mammary gland cells with sera exposed to cigarette smoke results in marked inhibition of the production of DHA from ALA. The products in smoke responsible for this effect, are being identified through mass spectrometric techniques. In conclusion, pharmacological agents and toxic compounds, such as oxysterols and smoke products affect key steps in the synthesis of the LCP, major bioregulators in mammalian cells.

Animals↗