Biomedical subjects

L Cabrini

Publications and source records attributed to L Cabrini.

At least 19 recordsLinked to original sources

PubMed2005

Correlation between dietary polyunsaturated fatty acids and plasma homocysteine concentration in vitamin B6-deficient rats.

BACKGROUND AND AIM: Vitamin B6 as cofactor of Delta6 desaturase is involved in polyunsaturated fatty acid metabolism; moreover, it is a cofactor of the trans-sulfuration pathway of homocysteine. Some studies report that low concentrations of pyridoxine, by increasing homocysteine levels, are associated with coronary artery disease, and carotid and arterial lesions. The aim of this study was to verify whether different dietary amounts of polyunsaturated fatty acids associated with low content of vitamin B6 could modulate homocysteinemia. METHODS AND RESULTS: Thirty-two rats were divided into two groups, one fed a diet with adequate vitamin B6 content the other a diet containing low amount of the same vitamin. Within each group, rats were divided into two subgroups differing in the polyunsaturated fatty acid content of the diet (63 and 33%, respectively). The vitamin B6-deficient diet induced an increase in homocysteine concentration compared to the vitamin B6-normal diet. This increase was tenfold in the subgroup fed high polyunsaturated fatty acid levels and twofold in the other subgroup. The fatty acid composition of liver phospholipids showed a lower arachidonic acid relative molar content and a lower 20:4/18:2 ratio in vitamin B6-deficient groups compared with B6-normal groups. CONCLUSIONS: On the basis of the different biological functions of pyridoxine and considering that some factors closely related to atherosclerosis are vitamin B(6) dependent, adequate pyridoxine availability could be necessary to assure a normal long chain fatty acid metabolism and to reduce the risk linked to hyperhomocysteinemia.

Animals↗

PubMed2002

Primary pancreatic lymphoma.

Primary pancreatic lymphoma (PPL) is a rare form of extranodal lymphoma (less than 0.5% of pancreatic tumors) originating from the pancreatic parenchyma. Histopathological examination is usually mandatory to obtain a definitive diagnosis since symptoms and radiological features are quite similar to those of other pancreatic masses. Percutaneous fine-needle aspiration (FNA) of the pancreas requires experienced cytopathologists as well as advanced immunohistochemical assays to obtain a final diagnosis on a small amount of tissue. A 46-year-old man complaining of watery diarrhea and severe weight loss (more than 20 kg) for more than 1 year was admitted to our hospital due to severe diabetic crisis. Enlarged lymph nodes (2.5 x 1 cm) were found at the right axillary stations. Abdominal ultrasound revealed the presence of a large hyperechogenic mass, mainly located at the pancreatic head. Abdominal computed tomography scan confirmed a diffuse enlargement of the head and body of the pancreas associated with lymphadenopathy along the lesser gastric curvature. Percutaneous ultrasound-guided FNA of the pancreas as well as gross biopsy of the axillary lymph nodes were unable to identify the nature of the mass. Diagnostic laparoscopy was performed: several enlarged lymph nodes along the lesser gastric curvature were revealed. Multiple biopsies of the pancreatic head were taken and lymphadenectomy along the lesser curvature and the hepatic hilus was also performed. The definitive histopathological examination of the pancreatic specimen revealed a primary low-grade non-Hodgkin B cell pancreatic lymphoma. The postoperative course was unremarkable; the patient underwent systemic chemotherapy regime for low-grade B cell Hodgkin lymphoma and he was symptom free at 9-month follow-up.

Diabetes Mellitus, Type 1↗

PubMed2001

Antioxidants and total peroxyl radical-trapping ability of olive and seed oils.

The presence of the oxidized and reduced forms of ubiquinones Q(9) and Q(10) was determined in commercial extra virgin olive and seed oils, where the amounts of alpha- and gamma-tocopherols and beta-carotene were also quantitated. Very high concentrations of ubiquinones were found in soybean and corn oils. Furthermore, the total antioxidant capability of each oil was evaluated by measuring total radical-trapping antioxidant parameters (TRAP) in tert-butyl alcohol and using egg lecithin as the oxidizable substrate. These values decreased in the order sunflower > corn > peanut > olive; the highest TRAP, which was found in sunflower oil, was related to the very high amount of alpha-tocopherol. Olive oil, because of the low content of alpha-tocopherol, exhibited a TRAP value approximately one-third that of sunflower oil. TRAP values of corn and soybean oils, in which low amounts of alpha-tocopherol but very high contents of gamma-tocopherol and reduced ubiquinones were present, were intermediate. gamma-Tocopherol exhibited a poor ability of trapping peroxyl radicals in tert-butyl alcohol. This behavior was probably due to the effects of the solvent on the rate of hydrogen abstraction from this phenol.

Antioxidants↗

PubMed2000

Resveratrol inhibition of lipid peroxidation.

To define the molecular mechanism(s) of resveratrol inhibition of lipid peroxidation we have utilized model systems that allow us to study the different reactions involved in this complex process. Resveratrol proved (a) to inhibit more efficiently than either Trolox or ascorbate the Fe2+ catalyzed lipid hydroperoxide-dependent peroxidation of sonicated phosphatidylcholine liposomes; (b) to be less effective than Trolox in inhibiting lipid peroxidation initiated by the water soluble AAPH peroxyl radicals; (c) when exogenously added to liposomes, to be more potent than alpha-tocopherol and Trolox, in the inhibition of peroxidation initiated by the lipid soluble AMVN peroxyl radicals; (d) when incorporated within liposomes, to be a less potent chain-breaking antioxidant than alpha-tocopherol; (e) to be a weaker antiradical than alpha-tocopherol in the reduction of the stable radical DPPH*. Resveratrol reduced Fe3+ but its reduction rate was much slower than that observed in the presence of either ascorbate or Trolox. However, at the concentration inhibiting iron catalyzed lipid peroxidation, resveratrol did not significantly reduce Fe3+, contrary to ascorbate. In their complex, our data indicate that resveratrol inhibits lipid peroxidation mainly by scavenging lipid peroxyl radicals within the membrane, like alpha-tocopherol. Although it is less effective, its capacity of spontaneously entering the lipid environment confers on it great antioxidant potential.

Antioxidants↗

PubMed1998

Dual influence of aging and vitamin B6 deficiency on delta-6-desaturation of essential fatty acids in rat liver microsomes.

Delta-6-desaturase (D6D) activity is influenced by many nutritional and non-nutritional factors, among which one of the most important is aging. D6D activity could be susceptible to the dual influence of aging itself and of nutritional deficiencies, due to the reduced intake and/or absorption of essential nutrients. Particularly, vitamin B6 deficiency might be a crucial factor for D6D activity in aged people. Using 20 month old Sprague-Dawley rats fed a diet with a subnormal level of vitamin B6, we evaluated D6D activity for linoleic acid (LA) and alpha-linolenic acid (ALA) in liver microsomes, and the fatty acid composition of microsomal total lipids. We observed a diminished D6D activity for LA and also for ALA in vitamin B6-deficient animals, being approximately 63% and 81% respectively of the corresponding activity in control rats. As a consequence, significant modifications in the relative molar content of microsomal fatty acids were observed. The content of arachidonic and docosahexaenoic acid, the main products of the conversion of LA and ALA respectively, decreased, LA content increased and a decrease in the unsaturation index was observed in liver microsomes of B6-deficient rats. The foregoing results suggest that the impairment of D6D activity by vitamin B6 deficiency might be an important factor in decreasing the synthesis of n-6 and n-3 PUFAs. This may be particularly important in aging, where D6D activity is already impaired.

Aging↗

PubMed1998

HPLC and light scattering detection allow the determination of phospholipids in biological samples and the assay of phospholipase A2.

Some applications to biological samples of a method for the separation and the quantitative analysis of phospholipids by high performance liquid chromatography (HPLC) and light scattering mass detection are described. Results obtained in the determination of phospholipid classes from rat tissues such as liver, heart and kidney have been compared with data from the literature. The method has been applied to the evaluation of phospholipids in human low-density lipoproteins (LDL), about which little is known. The procedure is also suitable for a rapid and reliable assay of the water-soluble phospholipase A2 activity; the relationship between the aggregation state of substrate phospholipids (mixed micelles, multilamellar and unilamellar vesicles) and the enzyme activity has been studied.

Animals↗

PubMed1998

Vitamin B6 deficiency affects antioxidant defences in rat liver and heart.

We have evaluated the effects of a diet containing normal amounts of lipids and a marginal content of vitamin B6 on lipid peroxidation. Pyridoxal phosphate concentrations of plasma and liver indicated that an initial deficiency state was reached. Vitamin B6 deficiency led to peroxidative stress: TBARS production was higher in the liver (+18.6%) and even more in the heart (+61%) of deficient rats as compared with controls. Furthermore, significant stimulation of glutathione-dependent enzymes occurred in both heart and liver of deficient rats: glutathione peroxidase activity increased in heart (+144%) and liver (+505%); glutathione reductase increased in heart (+54.9%) and liver (+15.5%). No difference in the total glutathione content of the organs of the two groups was observed. The reduced glutathione/oxidized glutathione ratio was significantly lower in deficient rats. Although the activity of glutathione-dependent enzymes was significantly greater in deficient rats than in controls, this stimulation was only partially able to counteract the peroxidative damage due to vitamin B6 deficiency.

Animals↗

PubMed1998

[Interposed abdominal compression in mechanical cardiopulmonary resuscitation. Description of a clinical case].

Among the different techniques proposed to integrate the standard cardiopulmonary resuscitation (sCPR) protocol, mechanical CPR (mCPR) and interposed abdominal compression (IAC) were found to be particularly effective for the simplicity of the procedure and the significant results obtained. A case of a 54-year old male with cardiogenic shock following viral infection, in which prolonged mechanical cardiopulmonary resuscitation with interposed abdominal compression was performed, is presented. Five hours after admission in the ICU, the patient's condition worsened with subsequent cardiac arrest with pulseless electrical activity (PEA). Mechanical CPR was promptly started, subsequently associated with IAC and prolonged for 1 hour and 20 minutes. Although the patient survived for only eight hours following cardiac arrest, prolonged IAC-mCPR allowed to start extra corporeal circulation (CPP). The patient was then transferred to the cardiosurgical operating theatre for ventricular assistance by centrifugal pump (VAP). Cardiovascular data obtained from patients monitoring did not shown any cardiac lesions or adverse effects as observed by autoptic examination and suggest the reliability of this mechanical method, which allows a better performance when compared to standard CPR. In prolonged resuscitations a few contraindications to both mCPR and IAC suggest the application of the associated techniques at all times in cardiac arrest, combining the benefits of both procedures.

Abdomen↗

PubMed1997

Iron (III) stimulation of lipid hydroperoxide-dependent lipid peroxidation.

In an experimental system where both Fe2+ autoxidation and generation of reactive oxygen species is negligible, the effect of FeCl2 and FeCl3 on the peroxidation of phosphatidylcholine (PC) liposomes containing different amounts of lipid hydroperoxides (LOOH) was studied; Fe2+ oxidation, oxygen consumption and oxidation index of the liposomes were measured. No peroxidation was observed at variable FeCl2/FeCl3 ratio when PC liposomes deprived of LOOH by triphenylphosphine treatment were utilized. By contrast, LOOH containing liposomes were peroxidized by FeCl2. The FeCl2 concentration at which Fe2+ oxidation was maximal, defined as critical Fe2+ concentration [Fe2+]*, depended on the LOOH concentration and not on the amount of PC liposomes in the assay. The LOOH-dependent lipid peroxidation was stimulated by FeCl3 addition; the oxidized form of the metal increased the average length of radical chains, shifted to higher values the [Fe2+]* and shortened the latent period. The iron chelator KSCN exerted effects opposite to those exerted by FeCl3 addition. The experimental data obtained indicate the kinetics of LOOH-dependent lipid peroxidation depends on the Fe2+/Fe3+ ratio at each moment during the time course of lipid peroxidation. The results confirm that exogenously added FeCl3 does not affect the LOOH-independent but the LOOH-dependent lipid peroxidation; and suggest that the Fe3+ endogenously generated exerts a major role in the control of the LOOH-dependent lipid peroxidation.

Catalysis↗

PubMed1995

Injury of rat thymocytes caused by exogenous peroxyl radicals in vitro.

The aim of this study was to investigate oxidative cell injury in rat thymocytes under conditions of radical generation exterior to the cell utilizing the thermolabile azocompound 2,2'-azobis(2-amidinopropane) dihydrochloride to generate peroxyl radicals at a constant and reproducible rate. This initiator, being water-soluble and endowed with a positive charge, is suitable for studies on oxidative damage of biomembranes induced in the external water environment. The relationship between cell viability, lipid and thiol oxidation and chain-breaking antioxidant depletion was studied. During the first hour of treatment cell viability decreased slightly, protein sulfhydryl groups were consumed slowly and no significant production of conjugated dienes occurred. After 90 min of incubation, when thymocyte permeability started to increase, the concentration of alpha-tocopherol decreased gradually, significant changes of polyunsaturated fatty acids occurred and a rapid phase of thio oxidation commenced. It can be concluded that, under conditions of an exogenous oxidant challenge, initially the cell membrane provides a physical barrier to the entrance of radicals to the thymocyte. When peroxyl radicals gain access to the membrane and the molecular barrier begins to disorganize, the oxidizable cellular components become susceptible to massive attack.

Amidines↗

PubMed1994

Peroxidation potential of rat thymus during development and involution.

The thymus of rats of ages between 1 and 7 months was homogenised and subjected to oxidative stress induced by iron salts. Lipid peroxidation, protein thiols and glutathione status were evaluated. The thymus of rats of 1 month of age exhibited lower susceptibility to the radical attack with respect to the thymus of rats between 3 and 7 months of age. This susceptibility was correlated with the content of polyunsaturated fatty acids and of lipophylic chain-breaking antioxidants.

Aging↗

PubMed1993

Ubiquinol-3 and ubiquinol-7 exhibit similar antioxidant activity in model membranes.

This study was undertaken to compare, on a kinetic basis, the antioxidant efficiency of an ubiquinol homologue having a short isoprenoid side-chain length, such as ubiquinol-3, with that of the long chain ubiquinol-7, by determining their rate constants of inhibition with respect to alpha-tocopherol. To this purpose we incorporated ubiquinol-3, or ubiquinol-7, or alpha-tocopherol into liposomes of egg yolk lecithin, and triggered lipid peroxidation with the thermal decomposition of a lipophilic azocompound. The results show that: i) the rate constants of inhibition for the two quinols are similar and slightly lower than that of alpha-tocopherol; ii) the length of the radical chain obtained in the presence of the two quinols is almost the same. From these data we concluded that the two homologues tested behave as chain-breaking antioxidants with quite similar effectiveness.

Antioxidants↗

PubMed1993

[Conventional radiology and computerized axial tomography in the diagnosis of pneumothorax in intensive therapy. Retrospective study of 2 years of activity].

The role played by chest radiograph and CT scan in diagnosis of pneumothorax is analyzed in a retrospective study based on two years of activity in Intensive Care Unit. The sensibility of traditional chest radiography was 75% while the sensibility of CT scan resulted higher (87.5%). In the authors opinion, when pneumothorax is suspected, particularly in patients with polytrauma, CT scan of the chest is mandatory unless patient's conditions or logistic difficulties related with transport of the patient contraindicate it.

Adult↗

PubMed1993

Relative susceptibility of the thymus and thymocytes to lipid peroxidation.

Thymus and thymocytes peroxidizability was studied in well defined conditions where lipid hydroperoxide dependent peroxidation occurs. The results show that: (i) lipid peroxidation is very low in thymocytes notwithstanding the higher content of arachidonic acid; (ii) the amounts of lipophilic chain-breaking antioxidants is higher in thymocytes; (iii) the thymus contains more total lipids and phospholipids. Thus the higher sensitivity to peroxidation of the thymus can be due to the replacement of thymus parenchyma by fatty tissue not correlated to an increase of lipophilic antioxidants.

Animals↗

PubMed1992

The antioxidant activity of ubiquinol-3 in homogeneous solution and in liposomes.

With a view to determining the antioxidant effectiveness of ubiquinol, the autoxidation of egg phosphatidylcholine initiated by an azocompound was studied both in homogeneous solution and in liposomes, either in the presence or in the absence of ubiquinol-3. The results show that ubiquinol behaves as a chain-breaking antioxidant by trapping lipid peroxyl radicals, its inhibition rate constant being about one half of that of alpha-tocopherol in both systems under investigation. In organic solvents the stoichiometric factor was found approx. 2 and in liposomes approx. 0.5, i.e. one fourth of that of alpha-tocopherol. We suggest that the lower value found in model membranes is due to autoxidation of the quinol itself by a radical chain reaction taking place at the polar interface. Ubiquinol-3 exhibits a sparing effect toward alpha-tocopherol, both in liposomes and in tert-butanol. It is suggested, on a thermodynamic basis, that the regeneration of vitamin E from the corresponding radical is more likely to occur by reaction with the ubisemiquinone rather than with the ubiquinol. Although these results, obtained in in vitro systems, can not be directly extrapolated to an in vivo system, they may be useful to clarify the antioxidant role of ubiquinol in biomembranes.

Antioxidants↗

PubMed1992

Extraction of lipids and lipophilic antioxidants from fish tissues: a comparison among different methods.

1. Lipids, phospholipids and lipid soluble antioxidants were extracted from Sparus auratus liver and white muscle by three different methods and the yields obtained were compared. 2. None of the three procedures can recover the above components with the same efficiency. 3. For comparison the methods were also applied to rat liver homogenates. 4. The choice of the extraction procedures depends on the tissue investigated and on specific research requirements.

Animals↗

PubMed1992

The influence of phospholipid polar head on the lipid hydroperoxide dependent initiation of lipid peroxidation.

In a buffer (Mes) and at a pH (6.5) where Fe2+ is very stable, we have studied the peroxidation of liposomes catalyzed by FeCl2. The liposomes studied, prepared by sonolysis, contained either phosphatidylcholine or 1:1 molar ratio of phosphatidylcholine and phosphatidic acid. The presence of the negatively charged phospholipid causes: 1) rapid Fe2+ oxidation and oxygen consumption; 2) increased generation of lipid hydroperoxides; 3) decreased generation of thiobarbituric acid-reactive materials; 4) very low inhibition of Fe2+ oxidation and lipid hydroperoxide generation by BHT; 5) inhibition of the termination phase of lipid peroxidation at high FeCl2 concentrations. A hypothesis is proposed to explain the results obtained.

Ferrous Compounds↗

PubMed1991

The role of the side chain in the antioxidant activity of ubiquinones.

The question has been addressed whether the side chain contributes to the antioxidant activity of Ubiquinones. The length, the chemical composition and structure of the chain have been considered. The effect of the actual concentration of the quinone in egg lecithin vesicles has been investigated by means of both UV spectroscopy and time resolved fluorescence quenching experiments of 12-AS. The results indicate that the antioxidant properties of the quinone do not seem to depend on the side chain.

Antioxidants↗