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Biomedical subjects

S Passi

Publications and source records attributed to S Passi.

86 records · Page 5Linked to original sources
PubMed1976

Growth requirements and lipid metabolism of Pityrosporum orbiculare.

The yeast, Pityrosporum orbiculare, isolated from lesions from lesions of tinea versicolor, grows in vitro only if fatty acids from the C12 to C24 series are added to the culture medium. Except for elaidinic and nervonic acids, all saturated and unsaturated fatty acids tested support growth. P. orbiculare can synthesize various lipid fractions containing both saturated and unsaturated fatty acids from a single fatty acid. Glucose and asparagine stimulate growth but exogenous vitamins do not.

Culture Media↗
PubMedDate not supplied

Simultaneous determination of sorbic acid, benzoic acid and parabens in foods: a new gas chromatography-mass spectrometry technique adopted in a survey on Italian foods and beverages.

A gas chromatographic-mass spectrometric technique is described for the simultaneous determination of sorbates, benzoates and other lipophilic preservatives in foods and beverages. The selected ions monitoring (SIM) technique allowed unambiguous identification of the compounds under study. This methodology eliminated all kinds of interferences from the complex food matrices which affect most routinely-used techniques, HPLC included. A very simple and time-saving extraction procedure was therefore employed, since subsequent purification steps were unnecessary, even for detection of trace levels of preservatives. The detection limits fell within the range of 100-200 pg. With this analytical technique, we have conducted a survey on sorbic acid, benzoic acid, methyl, ethyl, and propyl 4-hydroxybenzoate levels in 249 samples of foods and beverages on sale in markets in the Rome area. Samples were chosen from among those currently preserved by these additives. All compounds were also determined by a routinely-used HPLC technique for method comparison.

Benzoates↗
PubMedDate not supplied

Ergosterol oxidation may be considered a signal for fungal growth and aflatoxin production in Aspergillus parasiticus.

The addition of compounds able to peroxidize cell lipids (carbon tetrachloride (CCl4), cumene hydroperoxide (CUH), or linoleic acid hydroperoxide (LAH)) to 5-day-old Czapek-Dox Medium cultures of Aspergillus parasiticus induces a significant reduction of the tri-unsaturated ergosterol (ERG) levels in fungal microsomes and mitochondria, whereas the concentrations of the di-unsaturated linoleic acid (LA; C18:2 n-6) are unaffected. Aflatoxin (AFT) output follows ERG reduction and is associated with both a renewal of fungal growth and a slow increase of ERG concentration in subcellular membranes. We suggest that, by analogy with the regulatory role played on cell proliferation and metabolism by polyunsaturated fatty acid by-products (eicosanoids) in mammalian membranes, by-products of ERG oxidation may be considered triggers sufficient to induce both further fungal growth and AFT biosynthesis.

Aflatoxins↗
PubMedDate not supplied

[Determination of the cercarial lipids and relations with superficial human cutaneous lipids (author's transl)].

The lipid class composition of cercariae of Schistosoma mansoni and skin surface has been examined by thin lager chromatography. Free sterols, sterol esters, triglycerides, phospholipids were major components of cercarial lipids, triglycerides, wax esters, free fatty acids, squalen were major components of skin surface lipids. An examination of fatty acids of total cercarial and skin surface lipids revealed that C16, C18, C18=, C16=, C18= were major components.

Chromatography, Gas↗
PubMedDate not supplied

Oxidative stress in patients with multiple sclerosis.

It is well known that brain and nervous system cells are prone to oxidative damage because of their relatively low content of antioxidants, especially enzymatic ones, and of the high levels of both membrane polyunsaturated fatty acids (PUFA) and iron easily released from injured cells. We have investigated the oxidative stress in the blood (plasma, erythrocytes and lymphocytes) of 28 patients affected with multiple sclerosis (MS) and of 30 healthy age matched controls, by performing a multiparameter analysis of non-enzymatic and enzymatic antioxidants--Vitamin E (Vit. E), ubiquinone (UBI), reduced and oxidized glutathione (GSH, GS-SG), superoxide dismutase (SOD), glutathione peroxidase (GPX), catalase (CAT) and fatty acid patterns of phospholipids (PL-FA). PL-FA and Vit. E were assayed by GC-MS; UBI and GSH/GS-SG by HPLC; SOD, GPX and CAT by spectrophotometry. In comparison to controls, patients with MS showed significantly reduced levels of plasma UBI (0.21 +/- 0.10 vs. 0.78 +/- 0.08 mg/ml, p < 0.001), plasma Vit. E (7.4 +/- 2.1 vs. 11.4 +/- 1.8 mg/ml, p < 0.01), lymphocyte UBI (8.1 +/- 4.0 vs. 30.3 +/- 7.2 ng/ml blood, p < 0.001) and erythrocyte GPX (22.6 +/- 5.7 vs. 36.3 +/- 6.4 U/g Hb, p < 0.001). This blood antioxidant deficiency was associated with plasma levels of PL-PUFA--especially C20:3 n-6 and C20:4 n-6--significantly higher than controls. In conclusion, the blood of patients with MS shows the signs of a significant oxidative stress. The possibility of counteracting it by antioxidant administration plus an appropriate diet, might represent a promising way of inhibiting the progression of the disease. Antioxidant supplements should include not only GSH repleting agents, but also Vit. E, ubiquinol, and selenium.

Adult↗
PubMedDate not supplied

[The importance of man, mouse and rat skin surface lipid fractions on the "in vitro" penetration of "Schistosoma mansoni" cercariae (author's transl)].

The AA. have studied in this research, the rôle explicated in vitro from the lipids contained in a man's skin, in a rat of the Wistar experimental group and in a mouse of the Swiss one. They have seen that some lipids fractions, as triglycerides, waxes and squalenes explicate an action that favours the penetration of the cercariae in vitro on a plate of agar and that such an action is due to the unsaturation in the above said fractions of sebaceous origin. On the contrary the lipids of skin origin as sterols and their esters inhibit the penetration.

Animals↗
PubMedDate not supplied

[Lipids in Taenia saginata].

Lipids of Taenia saginata were analyzed by means of thin layer chromatography and gas liquid chromatography. Total lipids comprised about 3.3% of the fresh weight and consisted mainly of triglycerides (65.62%), sterols (19.58%), phospholipids (10.16%). The fatty acids of the triglycerides were mainly unsaturated and differed from those of phospholipids. The parasite has practically no "de novo" fatty acid biosynthesis, although this cestode did synthetize complex lipids from single lipids provided by the diet.

Animals↗