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The administration to male rats of 5 en % fish oil (FO) as supplement to a diet containing 5 en % corn oil (CO), selectively and markedly decreased arterial parameters (6-keto-PGF1 alpha formation and platelet antiaggregatory activity) assessed in isolated aortic segments perfused with autologous platelet rich plasma (PRP). Platelet parameters (ADP-induced aggregation, TxB2 formation in thrombin-stimulated PRP and sensitivity to exogenous PGI2) were instead minimally affected. Eicosapentaenoic acid (EPA, 20:5 n-3) did not accumulate in plasma, platelet and aorta lipids and arachidonic acid (AA, 20:4 n-6) levels declined markedly only in the plasma compartment. When FO was given alone at the same 5 en % level, both arterial and platelet parameters were similarly affected. EPA accumulated in plasma cholesterol esters and was present in appreciable concentrations also in platelets and aortic walls. AA levels declined markedly in plasma lipids and appreciably also in platelet and aorta lipids. It is concluded that a) arterial and platelet parameters are differentially affected by FO administration depending upon the presence of n-6 polyunsaturated fatty acids in the diet, b) 6-keto-PGF1 alpha production by arterial tissue does not seem to be related to changes of PG precursor fatty acid levels in the phospholipid fraction.

Summary The coumarin derivative AD6 was administered i.v. at the dose of 3 mg/kg/day to hypercholesterolaemic rabbits for a period of three weeks, while continuing the hypercholesterolaemic treatment (HC + AD6). A second group of hypercholesterolaemic (HC) rabbits was injected with saline and a third group of animals was composed of normal rabbits (N). Platelet aggregatory responses to arachidonic acid (AA) and collagen, thromboxane B2 (TxB2) formation after stimulation with collagen, 6 keto PGF1α formation following perfusion of isolated aortas with platelet-rich plasmas (PRP) and sensitivity of PRP to the inhibitory activity of exogenous prostacyclin (PGI2) were studied. Platelets of the HC rabbits were hyperactive to AA, were less sensitive to PGI2, produced less TxB2 after collagen stimulation, and perfused aortas of the same HC group produced more 6 keto PGF1α in respect to the N animals. Administration of AD6 to the HC animals normalized TxB2 production in stimulated PRP, platelet sensitivity to PGI2 and 6 keto PGF1α production in perfused aortas.

Objectives To assess fatty acid (FA) profiles in whole blood of 90 cystic fibrosis patients (CF) and 30 control subjects (C) and to correlate FA changes to the severity of respiratory disease. Methods Whole blood FA were assessed by GC with a micromethod-based analysis. Results Saturated and monounsaturated FA are higher, whereas polyunsaturated FA are lower in CF versus C with reduction of total n-6 FA, 22:5n-3 and 22:6n-3 (DHA). The product of linoleic acid (LA) × DHA, proposed as a marker for the disease, is 30% lower in CF than in C. Correlations with the severity of the respiratory disease are present for different FA and for the LA × DHA product. There is a reduction of Δ5 desaturase activity in CF, greater in severe disease, suggesting a basic metabolic alteration. Conclusions The micromethod-based analysis of blood FA facilitates the assessment of the FA status while confirming alterations of FA profiles already reported in specific blood compartments of CF.

Semisynthetic diets containing 8% by weight of either corn oil or butter were fed to male New Zealand rabbits for three weeks. The plasma cholesterol values were determined, the threshold concentrations for aggregation of platelet rich plasmas were measured for collagen and Na arachidonate, and the conversion of 14 C arachidonic acid to thromboxane B 2 and hydroxy fatty acids (HETE and HHT) at 10, 20 and 40 μM substrate concentrations were studied. The thresholds for arachidonate induced aggregation were lower and the amplitudes of collagen induced aggregations were greater in the butter fed than in the corn oil fed rabbits. Conversions of arachidonic acid to thromboxane B 2 but not to hydroxy fatty acids were greater in the butter fed rabbits at 10 and 20 μM substrate. The observed changes were accompanied by only slight modifications of plasma cholesterol levels.

Sex differences in eicosanoid production in platelets and vessel walls have been studied in control and n-6 fatty acid supplemented rats. In platelet rich plasma (PRP) of control female rats, arachidonic acid (AA) levels in phospholipids (PL), thromboxane B2 (TxB2) formation following collagen stimulation and aggregatory responses to collagen were higher than in PRP of male rats. 6 keto PGF1 alpha release from PRP-perfused isolated aortas were the same for both sexes, but the antiaggregatory activity of the wall was higher in males than in females, in association with a greater sensitivity of male platelets to prostacyclin. The administration of n-6 fatty acid supplements increased AA level in PL, TxB2 production and aggregation only in male platelets. Production of 6 keto PGF1 alpha and the antiaggregatory activity of aortic walls were reduced after dietary treatment in males, but biochemical and functional parameters were not correlated in females. The results indicate complex sex-related differences in fatty acid metabolism and eicosanoid production, and in responses to n-6 dietary fatty acids in platelets and the vascular system in the rat.

An experimental model for the study of platelet-vessel wall interactions has been developed, based on perfusion of rat platelet rich plasma (PRP) through isolated rat aortas. In the perfused PRP, platelet aggregation was inhibited and levels of 6 Keto PGF1 alpha and cAMP were elevated over the values found in non perfused PRP. When PPP or buffer were perfused through the isolated artery, elevations of 6 Keto PGF1 alpha levels in the perfusate were smaller (in perfused PPP) or of shorter duration (in both perfused PPP and buffer). The presence of platelets in the perfusion fluid thus enhanced the formation of Prostacyclin by the arterial wall. Levels of 6 Keto PGF1 alpha in PRP obtained from aspirin-treated animals and in PRP from normal animals, both perfused through normal aortas, were the same, and also levels of the above metabolite in normal PRP perfused through aortas of aspirin-treated animals did not differ from those found in non perfused PRP. It is concluded, from these data, that PRP does not stimulate PGI2 formation in perfused aortas by providing cyclic endoperoxides. The experimental model developed allows the study of interactions between normal platelets and aortas from experimentally treated animals or viceversa.

Pretreatments of rats with the Carbochromene derivative AD 6 (4 mg/kg i.p., 2 h before sacrifice) resulted in elevation of brain levels of 6-keto-PGF 1α in cerebral cortex under physiological conditions, had no effect on levels of TxB 2 and 6-Keto-PGF 1α at 30 min of hypoxia (respiration of 5% O 2 in N 2 ) and prevented the accumulation of TxB 2 occurring in brain at 5 min of recovery after hypoxia. In addition, the accumulation of LTC 4 and B 4 in brain sices incubated in the presence of the Ca ++ ionophore A23187 and arachidonic acid, was reduced in samples obtained from pretreated rats. The drug, thus, had favourable effects on the 6-keto-PGF 1α /TxB 2 ratio in normal conditions, as well as in conditions of altered oxygen supply. In addition it reduced the formation of compounds, the leukotrienes, which may exert pro-inflammatory activities on the cerebral microcirculation.

The nature and mineralogy of mixed Al and Fe(III) gels (initial Fe/Al molar ratios (Ri) of 1.0 and 2.5) formed at pH values ranging from 4.0 to 10.0, both in the presence and absence of citric acid (citrate/Fe + AI molar ratio (Rcit) of 0.01 and 0.1) and aged for a long period at room temperature and at 50°C have been studied. The complexes showed considerable differences in the mineralogy of the precipitation products. The samples formed at Ri = 1.0 contained ferrihydrite at pH 4.0, ferrihydrite + gibbsite at pH 5.0-7.0, and hematite + Al(OH)3polymorphs + ferrihydrite at pH 9.0-10.0. The samples formed at Ri = 2.5 had greater quantities of poorly crystallized ferrihydrite. Large amounts of Fe+Al (25-82%) were solubilized from the samples aged for 60 days at 50°C by ammonium oxalate. The addition of increasing concentrations of citrate to the gel suspensions containing equimolar amounts of Fe and AI strongly inhibited the formation of Al(OH)3polymorphs both at pH 5.0 or 8.5 by promoting the formation of short-range ordered materials. Citrate added initially to Fe-Al solutions (R*cit = 0.1) completely inhibited formation of crystals even after 135 days at 50°C.

Persons with CF can acquire Burkholderia cepacia complex (Bcc) infection through patient-to-patient contacts or from the environment. The former way of acquisition was well documented in the Prague CF centre where infection rate with a single B. cenocepacia strain ST32 reached over 30% in 1997–2003. The aim of this study was to compare epidemiological situation in the Centre in 2003 vs. 2010, and to evaluate efficacy of infection control in tackling the spread of ST32. System of surveillance exploiting typing techniques (RAPD and MLST) was set up in 2008. A total of 76 out of 211 patients examined by the end of 2003 (36.0%) were infected with Bcc; majority of them (78.9%) harboured epidemic strain ST32. Seven years later, Bcc positivity was detected in 72 out of 374 patients who attended the Prague CF clinic (19.3%). While 39 patients still suffered from infection with ST32 (54.2% of infected), a substantial portion of patients carried strains other than ST32 (see Table; note that ST number is specified only if more than two patients harboured the strain). Notably, only 2 patients within the ST32 group became positive after 2003, with the last case dated in May 2007. Epidemiological situation characterized by increasing heterogeneity of the Bcc population and no occurrence of new ST32 cases is a likely consequence of both healthcare workers’ and patients’ good compliance with strict infection control rules. Supported by NS10543−3, MSM0021620812 and MZ0FNM2005.

Il capitolo 10 descrive la metodologia di estrazione, frazionamento e di determinazione del carbonio organico del suolo.

La reazione è il singolo parametro capace di fornire il maggior numero di informazioni relative alle proprietà del suolo. In questo capitolo si esaminano i principali fattori capaci di determinarla, le sue relazioni con la fertilità del suolo ed i metodi analitici che ne permettono la determinazione.