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G Tomassi

Publications and source records attributed to G Tomassi.

At least 19 recordsLinked to original sources
PubMed2003

Induction of apoptosis in human pancreatic cancer cells by docosahexaenoic acid.

Polyunsaturated fatty acids have been indicated to induce anti-proliferative and/or apoptotic effects in various tumor cells. We showed that, at a 200- micro M concentration, both alpha-linoleic (18:2 n-6; LA) or docosahexaenoic (22:6 n-3; DHA) acid inhibited cell growth, while only DHA induced apoptosis in the human Paca-44 pancreatic cancer cell line. Investigating the mechanism underlying DHA-induced apoptosis, we showed that DHA induced a rapid and dramatic (>60%) intracellular depletion of reduced glutathione (GSH), without affecting oxidized glutathione (GSSG). Moreover, using two specific inhibitors of carrier-mediated GSH extrusion, cystathionine or methionine, we observed that GSH depletion occurred via an active GSH extrusion, and that inhibition of GSH efflux completely reversed apoptosis. These results provide the first evidence for a possible causative role of GSH depletion in DHA-induced apoptosis.

Apoptosis↗
PubMed1996

Aluminium levels in Italian diets and in selected foods from aluminium utensils.

In Italy, data on aluminium concentration in food items are scarce although aluminium containers are widely used to cook, to freeze or to wrap foods (foil) and it is known that aluminium can migrate from containers to foods. Therefore, an experimental study was carried out to quantify aluminium exposure from ingestion of actual total diets and from migration from containers to foods in conditions representative of the actual use. Samples of 24 h diets were collected, homogenized, lyophilized and the amount of aluminium was determined by atomic absorption spectrometry. The aluminium concentrations ranged from 1.0 to 2.1 mg/kg of food; the intake of aluminium ranged from 2.5 to 6.3 mg/day. The amount of aluminium migrating from aluminium cookware was determined by cooking various representative foods in aluminium and in glass or stainless steel containers. From comparison of the results, the increase in aluminium because of migration from cookware was relatively low, with the highest release into acidic and salty foods. The daily intake of aluminium even if all the foods were prepared and stored in aluminium containers would be approximately 6 mg/day, a very low value compared with the Provisional Tolerable Weekly Intake of 7 mg/kg body weight (equivalent to 60 mg/day for an adult man) established by the Joint FAO/WHO Expert Committee on Food Additives.

Aluminum↗
PubMed1996

Italian style brewed coffee: effect on serum cholesterol in young men.

BACKGROUND: Increases in blood lipids have been observed in humans when coffee is brewed by the boiling method. The purpose of this study was to evaluate if giving up Italian coffee might reduce blood cholesterol levels. METHODS: Eighty-four normolipidaemic young adult males, after a 3-week baseline (BL), were randomly assigned to three different regimens of coffee consumption: espresso (E), mocha (M), and no coffee, but tea (T). The average coffee consumption during intervention (I) was 3.1 +/- 1.2 and 2.8 +/- 1.1 cups per day for espresso and mocha group respectively (espresso: 25-35 ml/cup; mocha: 40-50 ml/cup). Total cholesterol, HDL-cholesterol, LDL-cholesterol and triglycerides were measured eight times during the study. Dietary pattern, alcohol consumption, smoking habits, drug use, and anthropometric data were also recorded. RESULTS: The changes observed in serum cholesterol concentration between baseline and intervention were not statistically different in all groups. The changes were 0.0 mmol/l (T), +0.01 mmol/l (E) and +0.05 mmol/l (M) for total serum cholesterol; 0 mmol/l (T), -0.02 mmol/l (E) and -0. 03 mmol/l (M) for HDL-C; -0.13 mmol/l (T), +0.02 mmol/l (E) and -0. 05 mmol/l (M) for LDL-C. Serum triglycerides showed a significant increase during intervention (P < 0.01 by ANOVA) in all groups with a change of 0.18 mmol/l, 0.18 mmol/l and 0.22 mmol/l, for tea, espresso and mocha group respectively. CONCLUSIONS: The results indicate that coffee brewed in the Italian way does not alter blood levels of total cholesterol, HDL-cholesterol and LDL-cholesterol, since no significant differences were observed in these blood parameters after a 6-week break from coffee consumption.

Adult↗
PubMed1995

Inhibition of human low-density lipoprotein oxidation by caffeic acid and other hydroxycinnamic acid derivatives.

The antioxidant activity of the major phenols derived from hydroxycinnamic acid (caffeic, ferulic, and p-coumaric acids) on in vitro LDL oxidation was screened, using Cu2+ as catalyst. The presence of the second phenolic hydroxy group enhanced the inhibitory effect of these compounds. In fact, at 5 microM concentration, only caffeic acid completely protected LDL from modification as measured as conjugated dienes formation and apo B-100 fragmentation, also preserving alpha-tocopherol. The effect of caffeic acid in inhibiting LDL oxidative modification induced by three different oxidant systems was tested. Using both Cu2+ and 2,2'-azobis (2-amidinopropane)-hydrochloride (AAPH), the inhibitory effect of caffeic acid was dose-dependent. Yet, the better protection was achieved in the metal-ion dependent system. Also the murine macrophages-mediated LDL oxidation was efficiently inhibited by 5 microM caffeic acid. UV-VIS spectra of caffeic acid incubated with cupric ions show the formation of a caffeic acid:copper complex, responsible for a transient chelating activity. This mechanism, coupled with its free radical scavenging property, accounts for the higher inhibitory activity exhibited by caffeic in Cu(2+)-catalyzed reaction.

Analysis of Variance↗
PubMed1995

[Trace elements: biological role and nutritional aspects for humans].

The methodological approaches generally adopted to ascertain the essentiality of trace elements present in human beings at levels of the order of magnitude of 1 micrograms g-1 or less are illustrated. An element is recognized as essential when it has a well defined function (as stabilizer, structural, hormonal or as enzymatic cofactor) and when it is always present in tissues and organs in well defined concentration ranges, when it induces reproducible physiological effects, when it is possible to prevent and treat consequences due to its deficiency by its supplementation. For the trace elements Co, Cr, Cu, Fe, I, Mn, Se and Zn a short summary of their biological functions in humans is presented. In particular, for each element an account is given of the mean total quantity accumulated by the human body, the distribution in the main organs, the most important pathways for their uptake and the recommended daily intake. These last values obviously do not take into consideration the synergic or antagonist action due to the intake of other substances that very often can modify the absorption and the metabolism of the element considered.

Diet↗
PubMed1992

Effect of dietary oils on lipid peroxidation and on antioxidant parameters of rat plasma and lipoprotein fractions.

In order to investigate the influence of fatty acid pattern and antioxidants other than vitamin E on lipid peroxidation and antioxidant levels of plasma very low density and low density lipoproteins (VLDL + LDL), the effects of three diets (equalized for vitamin E) containing soybean oil, olive oil, or an oleate-rich mixture of triglycerides (triolein) were studied in rats. A significantly lower concentration of thiobarbituric acid-reactive substances (TBA-RS) in plasma and lipoproteins was found after the olive oil diet (soybean oil, 3.7 +/- 0.4 nmol/ml; triolein, 2.1 +/- 0.5 nmol/ml; olive oil, 1.5 +/- 0.3 nmol/ml, in plasma) (soybean oil, 0.99 +/- 0.16 nmol/ml; triolein, 0.96 +/- 0.13 nmol/ml; olive oil, 0.38 +/- 0.12 nmol/ml, in the VLDL + LDL fraction). Furthermore, the results from in vitro copper-induced lipid peroxidation, expressed in terms of conjugated dienes, lipid hydroperoxides, and TBA-RS content, showed that VLDL + LDL particles from olive olive oil-fed rats were remarkably resistant to oxidative modification. The results suggest that the fatty acid unsaturation of dietary oils is not the only determining factor of the antioxidant capacity of lipoproteins in this animal model. The maximal protection observed after the olive oil diet may be explained by the presence of other unidentified antioxidants in addition to vitamin E, derived from oil intake. Therefore, the optimal balance between the content of unsaturated fatty acids and natural antioxidants in dietary oils appears to be of major importance.

Animals↗
PubMed1991

Effect of fish oil and coconut oil on antioxidant defence system and lipid peroxidation in rat liver.

Diets high in fish oil containing polyunsaturated fatty acids of the n-3 family, have been suggested to decrease the risk of cardiovascular disease. However these lipids are highly susceptible to oxidative deterioration. In order to investigate the influence of n-3 fatty acids on oxidative status, the effect of feeding rats with fish oil or coconut oil diets was studied by measuring different parameters related to an oxidative free radical challenge. Synthetic diets containing 15% (w/v) fish oil or coconut oil were used to feed growing rats for 4 weeks. As compared to control diet, the fish oil containing diet produced a significant decrease of cholesterol and triglyceride concentration in serum, however there was a significant increase in lipid peroxidation products. In addition, in fish oil fed animals, there was also a decrease in vitamin E and A concentration. Furthermore, the rate of lipid peroxidation in isolated microsomes was three fold higher in rats fed fish oil as compared to rats with coconut oil diet. No significant differences between the two experimental groups were observed in superoxide dismutase (SOD) and phospholipid hydroperoxide glutathione peroxidase (PHGPX) activities. However, there was a decrease in glutathione peroxidase (GPX) activity. These results suggest that fish oil feeding at an amount compatible with human diet, although decreasing plasma lipids, actually challenge the antioxidant defence system, thus increasing the susceptibility of tissues to free radical oxidative damage.

Animals↗
PubMed1990

Influence of dietary thermally oxidized soybean oil on the oxidative status of rats of different ages.

Young and aging rats were fed for different periods (10, 90, 180 and 365 days) diets containing 15% of fresh or heated soybean oil. Thiobarbituric reactive substances (TBA-RS), lipofuscin, superoxide dismutase (SOD), vitamin A, vitamin E and microsomal and mitochondrial fatty acids in liver, brain and serum were measured. Heated oil diets induced significant increase of TBA-RS levels in liver, with earlier effects in aging rats and affected SOD activity in aging rats only after a long period of feeding. Circulating and stored vitamin A were reduced in both young and aging rats, with earlier effects in young animals. Serum and liver vitamin E was significantly reduced in all test groups. The results indicate that heated unsaturated oil produces reduction in the antioxidative defense system and that vitamin E status is the earliest indicator of the oxidative effect regardless of age.

Aging↗
PubMed1987

Effect of dietary fats on hydroperoxide-induced chemiluminescence emission and eicosanoid release in the rat heart.

The effect of diets supplemented with three different fats (olive oil, sunflower oil, pork fat) on the susceptibility of the rat heart to oxidative stress and on the rate of eicosanoid release were studied. Our results show that when fatty-acid unsaturation of heart lipids is increased or vitamin E is decreased, even to a low degree, a marked enhancement of the susceptibility to hydroperoxide-induced oxidative stress (measured by chemiluminescence emission) occurs, which is associated with an increase of eicosanoid release from the heart.

Animals↗
PubMed1984

Morphological and biochemical changes in myelin subfractions of developing rats fed microbial lipids.

Morphological, biochemical, and physicochemical studies of myelin subfractions were undertaken on the progeny of Sprague-Dawley rats fed diets containing lipids either extracted from yeasts grown on n-alkanes or from margarine. Myelin subfractions obtained from pooled brain homogenates of littermates by sucrose density gradient centrifugation at 7, 14, and 21 days postnatally were subjected to electron microscopy, sodium dodecylsulfate polyacrylamide gel electrophoresis and assayed for 2', 3' cyclic nucleotide 3'-phosphohydrolase activity (CNPase; EC 3.1.4.37). Additionally, surface pressure measurements were made of lipid monolayers derived from myelin subfractions, which were subsequently injected with myelin basic proteins. The myelin subfractions of test animals, when compared with those of controls, show an earlier increase in the specific activity of CNPase, the earlier appearance of low-molecular-weight proteins, and an increase in the affinity of basic proteins for lipids derived from the myelin light fraction. This biochemistry suggests the presence of a more mature myelin between 7 and 14 days in the experimental group. The morphological studies, however, do not seem to concur with the biochemical data. The observed changes are discussed in relation to the influence of dietary lipids on myelinogenesis.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1983

Effect of dietary essential fatty acids on vitamin A utilization in the rat.

After their liver reserves of vitamin A were enhanced to ca. 300 micrograms retinol/g by 5 large daily oral doses of retinyl palmitate, groups of rats (n = 6) were fed a vitamin A-free diet containing 10% corn oil, coconut oil or linseed oil, with or without vitamin E, for a 10-day period. The composition of polyunsaturated fatty acids (PUFA) in liver lipids reflected the dietary composition, with linoleate and linolenate being markedly increased in the livers of rats fed the corn and linseed oil diets, respectively, relative to those fed the coconut oil diet. In contrast, the predominant retinyl ester in the livers of rats on all three diets was retinyl palmitate (greater than 80%), with no diet-related change noted in the relatively small amounts of retinyl linoleate (1-4%) or of retinyl stearate and linolenate (6-11%) present. The depletion of vitamin A from the liver during the 10-day period was slight (less than or equal to 10%) and similar on all three diets. Thus, the ingestion of polyunsaturated fatty acids, with or without vitamin E, did not significantly influence either the mobilization rate or the ester composition of liver vitamin A reserves of rats in good vitamin A status. The relationship of these studies to previous investigations in which PUFA was shown to reduce liver and plasma concentrations of vitamin A is discussed.

Administration, Oral↗
PubMed1982

Effects of dietary phospholipids and odd-chain fatty acids on the behavioural maturation of mice.

Five groups of female mice were fed from day 14 of pregnancy and throughout lactation on synthetic diets differing only in the lipid component, which constituted 10% of the diet and was derived from (a) the lipid fraction extracted from yeast grown on n-alkanes, (b) commercial soya lecithin, (c) fatty acids isolated from yeast lipids (off-chain fatty acids), (d) lipids extracted from yeast grown on glucose or (e) margarine (8%), corn oil (1%) and the unsaponifiable fraction (1%) from yeast grown on n-alkanes. A control diet (9% margarine and 1% corn oil) was fed to a sixth group of pregnant mice and to the offspring of all the groups from weaning to 60 days after birth. A battery of behavioural tests was performed on the offspring of the six groups between days 1 and 16 after birth (reflex activities), between days 2 and 21 (locomotor activity) and at 60 days of age (avoidance learning). An acceleration of postnatal behavioural maturation was evident in the pups of animals fed lipids from yeast grown on n-alkanes and of those fed soya lecithin, indicating the involvement of phospholipids and odd-chain fatty acids in the aspects of development studied.

Animals↗