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Biomedical subjects

P Zunin

Publications and source records attributed to P Zunin.

12 recordsLinked to original sources
PubMed2002

7-ketocholesterol in human and adapted milk formulas.

In the last few years, a variety of experimental and clinical studies concerning the formation, metabolism, and cellular effects of cholesterol oxidation products (COPs) have been carried out. Nevertheless, a substantial lack of knowledge exists regarding the possible intake of these compounds by the newborn through human and/or adapted formula milk. As far as the pathological role of COPs is concerned, exhaustive studies have shown that since dietary COPs are cytotoxic and atherotoxic, they may lead to adverse effects on health. The aim of this study was to investigate the possible development of cholesterol oxidation in adapted formula and in human milk by comparing the main cholesterol oxidation biomarker (7-ketocholesterol) concentration in both. To do so, the total (bonded and free) 7-ketocholesterol content was measured in ten fresh human mature milk samples and in ten milk adapted formula samples by high performance liquid chromatography and diode array detection. The 7-ketocholesterol human milk content (0.7+/-0.3) was often below the quantifiable limit (0.5 microg/g of extracted lipids) while 7-ketocholesterol adapted milk concentrations were often above (3.6+/-4.0) this limit. The 7-ketocholesterol content of adapted formula samples was significantly higher as compared to human milk samples (P<0.05). This is the first study to provide data concerning the concentrations of cholesterol oxides in human milk and in formula milk. Our results clearly suggest that the manufacturing technologies employed and the nutrient extractive sources play a crucial role in the development of cholesterol oxides in the end product. Careful surveillance has to be paid in order to avoid alteration of bioactive properties of nutrients and/or development of potentially toxic derivative compounds.

Cholesterol↗
PubMed1999

Deterioration of protein fraction by Maillard reaction in dietetic milks.

The development of the Maillard reaction in pasteurized, UHT and in-bottle sterilized dietetic milks was studied. In these products damage caused by heat treatments could increase as a result either of the addition of various ingredients or of manufacturing processes that alter their content of reducing carbohydrates. Protein damage was evaluated by measuring furosine by reversed-phase ion-paired HPLC. The levels of furosine detected made it possible to assess the amounts of biologically unavailable lysine. In all milks analysed blocked lysine values were < 340-350 mg/g total lysine, the level at which lysine becomes the limiting amino acid in milk. Pasteurized dietetic milks had levels of blocked lysine similar to that in ordinary pasteurized cows' milk. In some UHT and in-bottle sterilized dietetic milks their different composition resulted in an increase in the blocked lysine content. In some in-bottle sterilized milks, protein damage greatly reduces the beneficial effects of milk as a dietary supplement. Lactose-free milks, which are more susceptible to protein deterioration because of their higher content of reducing carbohydrates, were also analysed after storage at 20 degrees C and at < or = 4 degrees C. At the end of their recommended storage times, they contained limited amounts of blocked lysine only if they had been stored at < or = 4 degrees C.

Animals↗
PubMed1998

Sterol oxidation in infant milk formulas and milk cereals.

7-Ketocholesterol and 7-ketositosterol were chosen as reliable markers of the oxidation of cholesterol and phytosterols in infant milk formulas and infant milk cereals. A reversed-phase HPLC method was developed to measure them simultaneously in infant formulas. This method was then tested on a wide range of infant milk formulas and milk cereals on sale in Italy whose lipid composition is representative of the most common commercial formulas. The analytical results revealed no significant differences in the extent of oxidation of cholesterol and sitosterol. As the level of 7-ketocholesterol often followed the cholesterol level, a cholesterol content similar to that of human milk produced amounts of cholesterol oxides with possible negative effects on infant health. In contrast, the low cholesterol content of milk cereals never produced amounts of cholesterol oxides high enough to cause concern. The contents of phytosterols and hence their oxides were always low.

Animals↗
PubMed1984

[Essential fatty acids in adipose tissue].

Among the numerous causes of lipomobilization of fatty acids from the adipose tissue it is also carbon tetrachloride (CCl4). The research shows that the saturated fatty acids decreased in this tissue of the rats injected with CCl4, even if the linolenic and alpha-linolenic acids are present in the diet.

Adipose Tissue↗
PubMed1984

[Correlation between medium C-chain fatty acids and polyunsaturated fatty acids].

The medium C-chain fatty acids increased in the muscle, lungs, pancreas and adipose tissue (and not in the liver) of the rats injected with CCl4 or nourished with "balanced" diet for the lipids. When CCl4 and balanced diet are furnished together, these acids decrease strongly: the discussion of the results is difficult.

Adipose Tissue↗
PubMed1984

[Alpha-linolenic acid in the trophism of striated muscle].

Erucic and alpha-linolenic acids are probably related to a damage of muscle. The research was defined to the question if CCl4 that causes lesions in the tissue of the rat) damages also the muscle and if the dietary unsaturated fatty acids are effective in the prevention. The alpha-linolenic acid causes a strong reduction of the docosaesaenoic acid in the muscle, while the reduction of arachidonic acid is quite similar in all studied organs.

Animals↗
PubMed1984

[Essential fatty acids for ectodermic organs].

Damage of exocrine pancreas liver and lungs was induced by CCl4, probably because an unbalancement of essential fatty acids (EFA). The present research is made on the rats, injected with CCl4 subcutaneously and kept with diets at variable composition in linoleic acid, proceeding to the extraction of these organs for the gaschromatografic determination of fatty acids. CCl4 reduces the arachidonic acid in liver, pancreas and lungs of the injected rats and the dietary linoleic acid does not modify this picture in the organs.

Animals↗
PubMed1984

[Alpha-linolenic acid and its metabolic derivatives in the tissues of rats treated with CCl4].

The poly-unsaturated fatty acids of w-3 series were studied in the tissues of rats injected with CCl4 and also the effect of the alpha-linolenic acid added to the diet. Gascromathographic technique of fatty acids was applied on samples of liver, muscle, lungs, pancreas and adipose tissue. CCl4 was seen to increase in the liver and in the muscle the docosahexaenoic acid; the dietetic alpha-linolenic acid inhibits, in muscle, lungs and pancreas, the conversion of linoleic in arachidonic acid.

Adipose Tissue↗