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Biomedical subjects

P L Biagi

Publications and source records attributed to P L Biagi.

At least 55 records · Page 3Linked to original sources
PubMed1991

Fatty acid pattern of the different phosphoinositide fractions in human meningiomas.

Previous studies showed no differences in the phospholipid content of human meningiomas compared to normal leptomeninges, but only a higher unsaturation degree in the individual phospholipid fractions of tumors. Inasmuch as phosphoinositides play a role in the membrane responsiveness to numerous effectors, we studied the fatty acid pattern of the different phosphoinositide fractions of 14 human meningiomas of different histological origin. The fatty acid analysis revealed remarkable differences among the histological types, and, above all, among the different phosphoinositide fractions of a single tumor class. The phosphoinositides derived from transitional meningiomas appeared to be the most saturated ones, because of their low arachidonic acid content. Furthermore, in all the meningiomas, long chain polyunsaturated fatty acids were present only in the phosphatidylinositol fractions and the polyphosphorylated compounds appeared to be significantly different from the corresponding monophosphorylated ones. The possible significance of the different fatty acid distribution in the three phosphoinositide classes is discussed.

Adult↗
PubMed1991

Kinetic analysis of delta-6-desaturation in liver microsomes: influence of gamma-linoleic acid dietary supplementation to young and old rats.

Previous experiments demonstrated the ability-of a gamma-linoleic acid (GLA) dietary supplementation (as evening primrose oil--EPO) to counteract the fall off in delta-6-desaturase (D6D) activity of linoleic acid and alpha-linoleic acid in aged rats. Kinetic parameters of the D6D were determined in order to test the possibility that there may be a significant influence of GLA administration to young and aged rats on the Vm and Km values for 6-desaturation of both the substrates. In young rats GLA supplementation did not affect the kinetic parameters, while in old rats it produced an increase of Vm values of 6-desaturation for both the substrates. Thus the administration of small doses of GLA to old rats might offer substantial protection against the loss of D6D affinity observed in aging, enhancing the capacity of the enzyme itself.

Aging↗
PubMed1990

Delta-6-desaturase activity of human liver microsomes from patients with different types of liver injury.

The delta-6-desaturase (D6D) activity was evaluated in microsomes from liver fragments of cholecystectomized subjects without any liver pathology and from explanted liver of patients affected by cirrhosis of different etiologies. We observed a significant decrease in D6D activity, evaluated by a radiochemical technique using 1-[14C]-linoleic acid as substrate, in cirrhotic patients with no correlation with the etiology of the cirrhosis. The D6D activity within the pathological group was quite similar. No alteration in the 20:4/18:2 ratio obtained by gas chromatographic analysis of fatty acid methyl esters of microsomal membranes was found. Liver disease seems to be the main cause of the decreased enzyme activity independent of its etiology.

Adult↗
PubMed1990

Delta-6-desaturation of linoleic and alpha-linolenic acids in aged rats: a kinetic analysis.

Kinetic parameters of the delta-6-desaturation reaction were determined using both cis-linoleic and alpha-linolenic acid as substrates in liver microsomes of rats of different ages. The Km value for delta-6-desaturation of linoleic acid increased proportionally to the animal age, while the Vm did not change until 25 months of age. The Km values for alpha-linolenic acid were similar in young and senescent rats; on the contrary there was a significant aging influence on the Vm values. The affinity of the enzyme for the (n-3) series substrate was not so influenced by aging as the affinity for the (n-6) series substrate. This loss of affinity may be a key factor in aging through altering the polyunsaturated fatty acid content and distribution into cellular phospholipids.

Aging↗
PubMed1989

Age-related changes in linoleate and alpha-linolenate desaturation by rat liver microsomes.

The first and rate limiting step in the conversion of linoleic and alpha-linolenic acid is catalyzed by the delta - 6 - desaturase (D6D) enzyme. Rat liver microsomal D6D activity decreases on linolenic acid at a rate proportional to the animal age; on alpha-linolenic acid the decrease in D6D activity begins only later than on linoleic acid. The fatty acid composition of liver microsomes determined by gas chromatographic analysis confirms the impairment of the enzymatic activity directly measured. Our data indicate a correlation between aging and D6D activity impairment. The loss of D6D activity may be a key factor in aging through altering the eicosanoid balance.

Aging↗
PubMed1989

Effect of a hyperlipidic diet on lipid composition, fluidity, and (Na+-K+)ATPase activity of rat erythrocyte membranes.

Feeding rats a hyperlipidic diet in which animals were offered daily a variety of high-energy food resulted in a significant increase of serum free fatty acids and a decrease of phospholipids with respect to controls. On the contrary, there were no significant differences in erythrocyte membrane total lipid composition between the two groups. Erythrocyte membranes showed a significant decrease in saturated fatty acid content and a significant increase in (n-6) polyunsaturated fatty acid content; (n-3) polyunsaturated fatty acids significantly decreased. Membrane fluidity, investigated by fluorescence polarization of diphenylhexatriene, significantly increased in the erythrocyte membranes of the experimental group. These results seem compatible with the decreased saturated/unsaturated fatty acid ratio. A significant decrease of (Na+-K+)ATPase activity occurred in erythrocyte membranes of the experimental group rats with respect to the controls.

Animals↗
PubMed1989

Lipid composition, fluidity and enzymatic activities of rat liver plasma and mitochondrial membranes in dietary obese rats.

Total lipids and fatty acid composition were determined in liver plasma and mitochondrial membranes from control and dietary obese rats after 4 weeks of the experimental period. The lipid composition of liver plasma and mitochondrial membranes showed an increase of triacylglycerols in obese rats. The liver plasma membranes showed a decrease of saturated/unsaturated fatty acid ratio and an increase of (n-6) polyunsaturated fatty acids, whereas the (n-3) polyunsaturated acids were decreased. Contrary to what occurs with plasma membranes, few modifications were observed in mitochondrial membranes. Changes of the fatty acid composition of the phospholipid bilayer are of potentially great importance in structural and functional parameters of membrane. Fluidity of liver plasma membranes of dietary obese rats was highly increased, while the mitochondrial ones remained unchanged. These results can be well explained by the decreased saturated/unsaturated fatty acid ratio. A significant decrease of (Na+-K+) ATPase activity (a membrane bound enzyme) was found in plasma membranes of dietary obese rats. Mitochondrial enzymatic activities and oxidative phosphorylation showed few changes except a small, but significant decrease of state 3 respiratory rate. In this study we also determined the fatty acid composition of all the foods offered to animals and their daily intakes in order to discuss their possible influence on changes in structural and functional membrane parameters.

Animals↗
PubMed1988

A long-term study on the use of evening primrose oil (Efamol) in atopic children.

The effect of essential fatty acids on atopic eczema is controversial. Some workers have reported that patients with atopic eczema improved following oral treatment with evening primrose oil (an oil with a high concentration of gamma-linolenic acid), but others have disputed this. This study was designed to look at the effect of evening primrose oil as a long-term oral supplementation for children with atopic eczema. Treated children dramatically improved their clinical condition after 4 weeks of therapy, and this improvement was maintained during the whole period of treatment (20 weeks). At the same time, modifications in plasma, neutrophil and lymphocyte fatty acid composition were detected.

Child, Preschool↗
PubMed1988

Evening primrose oil (Efamol) in the treatment of children with atopic eczema.

It has been reported that essential fatty acid levels may be low and that there may be reduced levels of delta-6-desaturase metabolites of linoleic acid in patients with atopic eczema. Good therapeutic results have been reported on the use of evening primrose oil (Efamol) in adults but not in children. Efamol contains gamma-linolenic acid, the delta-6-desaturase metabolite of linoleic acid. The authors have studied 24 children with atopic eczema: 12 of them were treated with a higher dose of evening primrose oil than in previous studies and 12 with placebo olive oil. The clinical status and plasma, neutrophil and lymphocyte fatty acid composition in these children have been evaluated. After 4 weeks the eczema of essential fatty acid-treated children significantly improved in comparison with that of placebo-treated children (p less than 0.01). There were significant changes in plasma fatty acid composition between the basal values and the end of active treatment, and between the placebo and actively treated children. Neutrophil and lymphocyte fatty acid composition did not seem to be related to disease activity.

Child, Preschool↗
PubMed1988

Aging influence on delta-6-desaturase activity and fatty acid composition of rat liver microsomes.

The activity of delta-6-desaturase (D6D) in liver microsomes and fatty acid composition of microsomal lipids of rats of different ages were studied. The D6D activity was similar in suckling rats and in weaning rats. However, the enzyme showed a significantly decreased activity in oldest animals, and a linear correlation was found between the D6D activity and the animal age. The fatty acid composition data on total lipids of liver microsomes were consistent with the age-dependent changes in fatty acid desaturase activity. The major changes occurred in the linoleate and arachidonate fractions; the 20:4/18:2 ratio in liver microsomes decreased together with D6D activity during aging. The loss of D6D activity may be a key factor in aging through altering lipid membrane composition.

Aging↗
PubMed1986

Effect of ethanol intake on human erythrocyte membrane fluidity and lipid composition.

Erythrocyte membrane fluidity was evaluated in chronic alcoholic patients without any liver alteration, assuming different daily ethanol amounts, and in normal subjects and related to ghost fatty acid and total lipid composition obtained by high resolution gas chromatography. Erythrocyte membrane fluidity was significantly increased in a dose dependent manner in chronic alcoholic patients respect to normal subjects. This real fluidizing effect of ethanol "in vivo" was attributed mainly to a significant increase in the polyunsaturated fatty acids amount in patient ghosts in comparison with control subjects. On the other hand the cholesterol/phospholipid ratio was not significantly affected by chronic ethanol assumption.

Adult↗
PubMed1984

Normo and iperlipidic diet influence on fatty acid composition and mitochondrial functionality in rat heart.

This work reports the effect of normo and iperlipidic diets with different fatty acid content on some rat heart mitochondria functionality parameters. Normolipidic assumption according to their fatty acid pattern, affect the mitochondrial structure qualitative aspect but not significantly functionality. An oxidative phosphorylation slowing down is observed on group fed with iperlipidic diets, but not on groups fed with soja phospholipids, where this phenomenon seems to be mitigated.

Animals↗
PubMed1984

Dietary trans-fatty acid effects on mitochondrial functionality and phospholipid composition in rat perfused hearts in oxygenation and anoxia.

Dietary fatty acid fraction influence on heart composition is known and we have previously demonstrated a trans-fatty acid accumulation in heart. In this work we will verify trans-fatty acid effect on heart phospholipid fatty acid composition and miocardic mitochondrial respiratory activity under the influence of perfusion techniques in oxygenation and anoxic conditions. Results have pointed out, in group fed with 28% trans-fatty acid hydrogenated fat, a decreased mitochondrial functionality during perfusion in different oxygenation condition, probably correlated to different fatty acid composition of heart phospholipids.

Animals↗
PubMed1984

Fatty acid composition of single brain structures following different alpha linolenate dietary supplementations.

Weanling female rats randomly divided into three groups were fed a basal alipidic diet added with 10% (w/w) corn oil, soybean oil or linseed oil. After thirty and ninety days of dietary treatment the rats were killed and the fatty acid composition of brain, optic nerve and visual cortex was determined. The results demonstrate a different sensitivity to the diet of the different structures examined and, for the linseed oil treated rats, a strong decrease in the proportions of the total (n-6 + n-3) polyunsaturated fatty acids in all the structures examined.

Animals↗
PubMed1984

Nutritional studies on anti-alpha-amylase: II) Lipid metabolism investigation: fatty acid composition of organs and tissues.

The effect of dietary anti-alpha-amylase on some aspects of lipid metabolism has been studied after having shown that rats fed proteins from legumes containing anti-alpha-amylase (to cover one-third of the protein quota in the diet) failed to absorb carbohydrates contained in starch to the point that the total caloric intake was sharply reduced and their growth stunted. Upon feeding rats anti-alpha-amylase, destruction of fatty deposits was observed. The animals, on the other hand, did not show evidence of important structural pathology.

Animals↗