E. Agradi

SOYBEAN-PROTEIN DIET IN THE TREATMENT OF TYPE-II HYPERLIPOPROTEINÆMIA

A soybean textured protein induced a 14% decrease of plasma-cholesterol levels after two weeks and 21% after three when substituted for animal proteins in a group of 20 patients with type-II hyperlipoproteinaemia. Comparison of soybean diet with a standard low-lipid diet in the same patients, according to a cross-over protocol, indicated that this hypocholesterolaemic effect was not due to differences in the lipid composition of the two diets. The hypothesis that a soy protein has a hypocholesterolaemic action per se is supported by the results of a subsequent experiment in 8 type-II patients in whom the addition of cholesterol (500 mg/day) to soy protein did not modify the hypocholesterolaemic response.

Differential effects of dietary fatty acids on the accumulation of arachidonic acid and its metabolic conversion through the cyclooxygenase and lipoxygenase in platelets and vascular tissue.

Semisynthetic diets containing either corn oil (CO) or butter (B) (11 and 2.2 en % as linoleic acid, respectively) were fed to male rabbits for periods of 3 weeks and 3 months. The CO diet, in respect to the B diet, induced higher levels of linoleic acid (LA) and lower levels of arachidonic acid (AA) in platelet phospholipids, lower levels of AA in aortic phosphatidylinositol (PI) and accumulation of both LA and AA in liver lipids. The thresholds for aggregation with AA, but not with collagen, were higher in the CO group and the formation of thromboxane B2 (TXB2) from [14C] AA, but not from endogenous substrate after collagen stimulation, was lower in the same group. Formation of PGE2-like material by incubated aortas was higher in the B group. In the CO group, platelet cyclooxygenase appeared to be selectively depressed. The correlations among diet-induced fatty acid changes in platelet and aortic lipids, platelet aggregation and thromboxane and prostacyclin formation are discussed.

AFLP analysis as biomarker of exposure to organic and inorganic genotoxic substances in plants

In recent years several plant species have been in use as bioindicators and several tests have been developed to evaluate the toxicity of environmental pollutants in vegetal organisms. In the present paper Arabidopsis thaliana (L.) Heynh. (ecotype Wassilewskija) was used as bioindicators of two genotoxic substances: potassium dichromate and dihydrophenanthrene. Inhibition of seed germination was observed with both pollutants. AFLP analysis (i) indicated that both substances are genotoxic, (ii) showed that dihydrophenanthrene induces DNA changes in different target sequences than potassium dichromate, (iii) quantified the genotoxic effect using cluster analysis by comparing DNA from treated plants with that of control plants. On the basis of these considerations we suggest that AFLP method is a powerful tool for measuring qualitative and quantitative genotoxic activity due to environmental pollutants. AFLP method can be applied to a wide range of bioindicator organisms and may become a universal methodology to identify target genes for specific genotoxic agents. This could open up possibilities for designing specifically targeted assays and new approaches to risk assessment.

Hyperlipoproteinemia in alcoholic subjects

Summary Plasma lipid levels were tested in a group of a alcoholic patients admitted to an alcoholic ward. Triglycerides were significantly increased in comparison with a control population, most markedly in chronic alcoholics. Typing of hyperlipoproteinemia showed a high incidence of type IV disease. There appeared to be no correlation between triglyceride and free fatty acid elevation.

Diet, lipids and lipoproteins in patients with peripheral vascular disease.

Diet and some metabolic parameters of patients with peripheral vascular disease (PVD) were examined in order to investigate possible pathogenetic factors. Two hundred and eight of these patients (age range: 26-69) had an angiographic diagnosis of atherosclerotic disease (AD); they were age- and sex-matched with a control inpatient population. Evaluation of living and dietary habits, with the aid of appropriate computerized clinical charts, showed that AD patients had a significantly higher consumption of cigarettes, carbohydrates and alcohol than controls. In particular, 45.5 per cent of the patients vs 12.5 per cent of controls smoked more than 20 cigarettes daily; 28 per cent vs 16 per cent consumed more than 40 grams of sugar per day; and 54.5 per cent vs 21.5 per cent drank more than 500 ml of wine daily; these and other differences were statistically significant. Type IV hyperlipoproteinemia was almost three times as frequent among patients than among controls (46 per cent vs 18 per cent). Triglyceride levels were significantly more elevated in all age groups considered, while cholesterol levels were significantly higher only among patients of the 50-59 age group. Thirteen per cent of patients vs 5 per cent of controls had hyperuricemia. The findings of an increased carbohydrate and alcohol consumption, together with hypertriglyceridemia, may explain the higher incidence of PVD in Italy compared to the United States.

Effects of 8-monochloro-3-beta-diethylaminoethyl-4-methyl-7-ethoxy carboxyl methoxy coumarin (AD6) on aggregation, arachidonic acid metabolism and thromboxane B2 formation in human platelets

Summary Preincubation of human platelet rich plasma (PRP) with AD6 (8-monochloro-3-beta-diethylaminoethyl-4-methyl-7-ethoxy carboxyl methoxy coumarin), inhibits the aggregations induced by threshold concentrations of arachidonic acid sodium salt, collagen and ADP at concentrations of 25,50 and 100 γ/ml respectively. When preincubated at the concentrations of 100γ/ml, AD6 decreases the conversion of exogenous labelled arachidonic acid to thromboxane B2 by washed platelets. At the same concentration, AD6 decreases of more than 70% the production of TXB2 from endogenous substrate, following the stimulation of PRP with collagen. The compound appears to act more on the utilization of arachidonic acid for thromboxane production than on the arachidonic acid cyclooxygenase.

RAPD analysis and flavonoid composition of Aconitum as an aid for taxonomic discrimination

Abstract The RAPD technique and phytochemical analysis, based on the investigation of flavonoid composition, were used to study Aconitum vulparia , A. paniculatum , A. napellus subsp. tauricum (from two different localities), and A. napellus subsp. neomontanum . Twenty primers were screened for the genetic analysis and 14 were selected providing 51 polymorphic bands. The phenogram based on UPGMA clustering of Jaccard coefficient revealed a clear division between yellowish and blue Aconitum plants and inside this second group A. paniculatum is clearly separated from all populations belonging to A. napellus group. Also the flavonoid profile well characterise all species and subspecies under study.

Decrease of polyunsaturated fatty acids and elevation of the oleic/stearic acid ratio in plasma and red blood cell lipids of malnourished cancer patients

The fatty acids profiles of plasma and red blood cell lipids have been evaluated in 12 malnourished cancer patients in comparison with samples from eight healthy controls. In such patients, significantly lower levels of linoleic acid (LA) as percentage of total fatty acids were observed in plasma phospholipids (PL) and cholesterol esters (CE), and in red blood cells PL. The levels of arachidonic acid (AA) and the unsaturation index of the two lipid classes were also reduced in plasma CE but not in PL. In spite of the marked reduction of LA and, more generally, of total polyunsaturated fatty acids (PUFA), no elevation of eicosatrienoic acid (20:3 n-9) was observed, such acid being considered a typical index of essential fatty deficiency. Moreover, no modification of the parameters indicating impairment of the fatty acid desaturation activity was shown. In addition, the levels of palmitic and oleic acids were significantly higher in both plasma PL and CE and in red blood cells PL. The reported elevation of the oleic to stearic acid ratio in lipids of red blood cells from malnourished cancer patients, already observed by other authors, was confirmed in our study. This ratio was even more markedly elevated in plasma lipids of the patients. A very good correlation was found between the reduction of linoleic acid levels, especially in plasma CE, and weight loss, suggesting enhanced utilization of this fatty acid in association with extensive depletion of lipid stores, in this pathological state.

Influence of short term dietary supplementation of different lipids on aggregation and arachidonic acid metabolism in rabbit platelets

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 14C arachidonic acid to thromboxane B2 and hydroxy fatty acids (HETE and HHT) at 10, 20 and 40 microM 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 B2 but not to hydroxy fatty acids were greater in the butter fed rabbits at 10 and 20 microM substrate. The observed changes were accompanied by only slight modifications of plasma cholesterol levels.

Platelet-vessel wall interactions: Effects of platelets and plasma on the antiaggregatory activity and 6 keto-PGF1α production in isolated perfused aortas

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.