RESUMEN

The present report describes application of advanced analytical methods to establish correlation between changes in human serum proteins of patients with coronary atherosclerosis (protein metabolism) before and after moderate beer consumption. Intrinsic fluorescence, circular dichroism (CD), differential scanning calorimetry and hydrophobicity (So) were used to study human serum proteins. Globulin and albumin from human serum (HSG and HSA, respectively) were denatured with 8 m urea as the maximal concentration. The results obtained provided evidence of differences in their secondary and tertiary structures. The thermal denaturation of HSA and HSG expressed in temperature of denaturation (Td, degrees C), enthalpy (DeltaH, kcal/mol) and entropy (DeltaS kcal/mol K) showed qualitative changes in these protein fractions, which were characterized and compared with fluorescence and CD. Number of hydrogen bonds (n) ruptured during this process was calculated from these thermodynamic parameters and then used for determination of the degree of denaturation (%D). Unfolding of HSA and HSG fractions is a result of promoted interactions between exposed functional groups, which involve conformational changes of alpha-helix, beta-sheet and aperiodic structure. Here evidence is provided that the loosening of the human serum protein structure takes place primarily in various concentrations of urea before and after beer consumption (BC). Differences in the fluorescence behavior of the proteins are attributed to disruption of the structure of proteins by denaturants as well as by the change in their compactability as a result of ethanol consumption. In summary, thermal denaturation parameters, fluorescence, So and the content of secondary structure have shown that HSG is more stable fraction than HSA.

Asunto(s)

RESUMEN

The aim of this study was to evaluate the influence of beer consumption (BC) on the functional and structural properties of human serum proteins (HSP). Thirty-eight volunteers (after coronary bypass) were divided into two groups: experimental (EG) and control (CG). Nineteen volunteers of the EG consumed 330 mL per day of beer (about 20 g of alcohol) for 30 consecutive days. The CG volunteers consumed mineral water instead of beer. Blood samples were collected from EG and CG patients before and after the experiment. Albumin (Alb), globulin (Glo), and methanol-precipitable proteins (MPP) from human serum were denatured with 8 M urea. Fluorescence and electrophoresis were employed in order to elucidate urea-induced conformational changes and structural behavior of proteins. The measured fluorescence emission spectra were used to estimate the stability of native and denatured protein fractions before and after BC. It was found that before BC the fractions most stable to urea denaturation were Glo, Alb, and MPP fractions. After BC in most of the beer-consuming patients (EG) some changes in native and denatured protein fractions were detected: a tendency to lower stability and minor structural deviations. These qualitative changes were more profound in MPP than in Alb and Glo. Thus, Glo is more resistible to alcohol influence than Alb, which in turn is more resistible than MPP. No serum protein changes were detected in patients of CG.

Asunto(s)

RESUMEN

Dietary fibers, major phenolics, main minerals, and trace elements in persimmons and apples were analyzed and compared in order to choose a preferable fruit for an antiatherosclerotic diet. Fluorometry and atomic absorption spectrometry following microwave digestion were optimized for the determination of major phenolics and minerals. Total, soluble, and insoluble dietary fibers, total phenols, epicatechin, gallic and p-coumaric acids, and concentrations of Na, K, Mg, Ca, Fe, and Mn in whole persimmons, their pulps, and peels were significantly higher than in whole apples, pulps, and peels (P < 0.01-0.0025). Conversely, the contents of Cu and Zn were higher in apples than in persimmons. In persimmons and apples all of the above components were higher in their peels than in whole fruits and pulps. The relatively high contents of dietary fibers, total and major phenolics, main minerals, and trace elements make persimmon preferable for an antiatherosclerotic diet.

Asunto(s)

RESUMEN

The unfolding of human serum proteins (HSP) was studied by measuring the intrinsic fluorescence intensity at a wavelength of excitation corresponding to tryptophan's or typosine's fluorescence and surface hydrophobicity. The maxima emission wavelengths (lambdamax) of human serum albumin (HSA) and human serum globulin (HSG) before beer consumption (BC) were 336.0 and 337.0 nm and after BC shifted to 335.0 and 334.0 nm, respectively. The surface hydrophobicity slightly increased after BC. In a solution of 8 M urea the lambdamax of BSA shifted to 346.4 and that of BSG to 342.5 nm. In contrast, in the same solution but after BC the lambdamax positions of HSA and HSG shifted to 355.9 and 357.7 nm, respectively. A decrease in fluorescence intensity, a shift in the maximum of emission, and an increase in surface hydrophobicity which reflected unfolding of proteins were observed. Here we provide evidence that the loosening of the HSP structure takes place primarily in various concentrations of urea before and after beer consumption. Differences in the fluorescence behavior of the proteins are attributed to disruption of the structure of proteins by denaturants as well as by the change in their compactability as a result of ethanol consumption.

Asunto(s)

RESUMEN

Characterization of three cactus proteins (native and denatured) from Machaerocereus gummosus (Pitahaya agria), Lophocereu schottii (Garambullo), and Cholla opuntia (Cholla), was based on electrophoretic, fluorescence, CD (circular dichroism), DSC (differential scanning calorimetry), and FT-IR (Fourier transform infrared) measurements. The obtained results of intrinsic fluorescence, DSC, and CD were dissimilar for the three species of cactus, providing evidence of differences in secondary and tertiary structures. Cactus proteins may be situated in the following order corresponding to their relative stability: Machaerocereus gummosus (Pitahaya agria) > Cholla opuntia (Cholla) > Lophocereu schottii (Garambullo). Thermodynamic properties of proteins and their changes upon denaturation (temperature of denaturation, enthalphy, and the number of ruptured hydrogen bonds) were correlated with the secondary structure of proteins and disappearance of alpha-helix.

Asunto(s)

RESUMEN

Recent studies have shown that dietary fiber and polyphenols of vegetables and fruits improve lipid metabolism and prevent the oxidation of low density lipoprotein cholesterol (LDL-C), which hinder the development of atherosclerosis. The goal of this study was to measure the total polyphenol and dietary fiber contents of some tropical fruits (i.e., pineapple, wax apple, rambutan, lichi, guava, and mango) and compare the results to the content of these substances in the better characterized persimmon. It was found that lichi, guava, and ripe mango (cv. Keaw) have 3.35, 4.95, and 6.25 mg of total polyphenols in 100 g fresh fruit, respectively. This is significantly higher than in persimmon, pineapple, wax apple, mature green mango, and rambutan [P < 0.0005 for pineapple (Smooth Cayene variant), wax apple, persimmon, rambutan, mature green mango (cv. Keaw); the value of P < 0.001 is found only for pineapple (Phuket, Queen variant)]. The same relationship was observed for the contents of gallic acid and of dietary fiber. It can be supposed that among the studied fruit, lichi, guava, and ripe mango may be preferable for dietary prevention of atherosclerosis.

RESUMEN

Amaranth belongs to a nutritious class of pseudocereals. The well balanced amino acid composition of amaranth compared with those of major cereals would indicate that it deserves a quantitative study of its chemical properties. This work was undertaken to compare Amaranthus (A.) caudatus with a number of other plants on the basis of the sequences of various proteins and the composition of their alcohol-soluble protein mixture and glutelins. Alcohol-soluble proteins were extracted with 55% isopropanol (2-ProOH) + 5% 2-mercaptoethanol (2-ME) and glutelin fractions were obtained with borate buffer + 3% 2-ME + 0.5% sodium dodecyl sulfate (SDS), pH 10. Protein fractions were then electrophoreded on sodium dodecyl sulfate polyacrylamide gels (SDS-PAGE). FASTA and TFASTA programmes were used for comparison of amino acid sequences. Dot matrix analysis and secondary structure predictions which were drawn by Plot-structure, were taken from the GCG package. Electrophoretic tests failed to indicate significant correlation between prolamins from cereals and other plants with the alcohol-soluble fractions from amaranth, proving that these proteins cannot represent the main fraction in amaranth. On the other hand, glutelins shared some common electrophoretic bands with other cereals and showed some identity by SDS-PAGE. Amino acid sequences of A. caudatus (100% identity) had degrees of similarity in the range of 71.4 to 52.2% with rice, garden pea, jobs' tears, maize, and yam. Rice glutelin had similarity in the range of 93.3% to 44.8% with oats, soybean, and pea. Secondary structures of A. caudatus (using conservative amino acid replacement), jobs' tears and rice glutelins, oat globulin, and pea legumin sequences were predicted. Some relationship was shown among electrophoretic patterns of alcohol-soluble proteins and glutelins of A. caudatus.

Asunto(s)

RESUMEN

The effect of dietary persimmon (Pers, 7.0%) on lipid metabolism and antioxidant activity was investigated in 40 male Wistar rats adapted to cholesterol-free or 1% cholesterol diets. The rats were divided in four groups of 10. The basal diet contained wheat starch, casein, soybean oil, and mineral and vitamin mixtures. The control group (C) consumed the basal diet. To the basal diet were added 7 g/100 g dry persimmon (Pers), 1 g/100 g cholesterol (Chol), or both (Chol/Pers). The experiment lasted 4 wk. Plasma total cholesterol (TC), LDL cholesterol (LDL-C), HDL cholesterol (HDL-C), triglycerides (TG), total phospholipids (TPH), HDL phospholipids (HDL-PH), lipid peroxides (LP) and liver TC concentrations were measured. Groups did not differ before the experiment. In the Chol/Pers vs. Chol group, the persimmon-supplemented diet significantly (P < 0.05) lessened the rise in plasma lipids due to dietary cholesterol: TC (3.88 vs. 4. 88 mmol/L; -20%), LDL-C (2.24 vs. 3.27 mmol/L; -31%), TG (0.72 vs. 0. 89 mmol/L; -19%), LP (2.20 vs. 3.25 mmol/L; -32%) and TC in liver (32.8 vs. 49.9 micromol/g; -34%), (P < 0.001). The Chol/Pers diet significantly reduced the decrease in HDL-PH due to dietary cholesterol (0.73 vs. 0.58 mmol/L; -25.8%, P < 0.001) and decreased the level of TPH (1.32 vs. 1.73 mmol/L; -23%, P < 0.001). Persimmon in rats fed the basal diet without cholesterol did not significantly affect the variables measured. These results demonstrate that persimmon possesses hypolipidemic and antioxidant properties that are evident when persimmon is added to the diet of rats fed cholesterol. These properties are attributed to its water-soluble dietary fiber, carotenoids and polyphenols.

Asunto(s)

Asunto(s)

Asunto(s)

RESUMEN

Moderate consumption of ethanol lowers mortality from coronary artery disease, and one of the possible mechanisms is an antiarrhythmic action. We therefore investigated the effect of a small daily dose of beer on plasma electrolytes. 52 men who seldom drank alcohol, clinically stable more than one year after coronary bypass surgery, were randomized to drink either 330 mL beer (containing about 20 g ethanol) or mineral water with similar potassium, magnesium, calcium and sodium content daily for 30 days. Plasma electrolytes and liver function indices, and also heart rate, blood pressure and weight, were measured before and after the trial period. The only significant before-and-after difference was in the group consuming beer, whose plasma magnesium rose from 0.89 (SD 0.01) to 0.98 (SD 0.02) mmol/L (P < 0.0025). This level of beer consumption did no obvious harm to liver function and its possibly beneficial effect on plasma magnesium deserves further investigation.

Asunto(s)

RESUMEN

OBJECTIVES: The aim of this study was to evaluate the influence of moderate beer consumption on lipid metabolism and antioxidant activity in patients (pts) with coronary artery disease (CAD). SUBJECTS: Forty-eight male pts with CAD not alcohol beverages consumers were randomly divided into experimental (EG) and control (CG) groups, 24 pts each. SETTING: Rehovot University Hospital, Israel. INTERVENTION: Every patient of the EG during a period of 30 consecutive days consumed 330 ml of Maccabee beer (> 20 g of alcohol). The pts of the CG did not consume alcohol during the trial period. METHODS: A wide range of tests including total cholesterol, LDL-C, HDL-C, total tocopherol and alpha-tocopherol. RESULTS: Only in the pts of the EG were found a tendency to an increase of the level of HDL-C and a statistically significant rise in the level of total tocopherol (P < 0.025) and alpha-tocopherol (P < 0.025). CONCLUSIONS: Even a short period of moderate beer consumption leads to some favourable biochemical changes in blood of pts with CAD which are widely regarded as indicators of CAD prevention.

Asunto(s)

RESUMEN

OBJECTIVES: To evaluate the influence of a short period of moderate beer consumption on the status of the thrombolitic activity in patients with coronary artery disease (CAD). SUBJECTS AND DESIGN: From 28 patients with two- or three-vessel CAD 22 were randomly assigned to an experimental group (EG) and six to control group (CG). Before and after completion of the study every one of the 28 patients was examined and a wide range of laboratory tests was performed. SETTING: A University Hospital in Israel. INTERVENTION: Of the EG, 22 patients consumed 330 mL of beer day-1 (20 g of alcohol) for the 30-day period in addition to the usual antiatherosclerotic diet. Patients of the CG did not consume alcohol beverages. MAIN OUTCOME MEASURES: Fibrinogen, prothrombin time (PT), coagulant activity of Factor VII (F VIIc) and Factor VII antigen (F VIIag), and plasminogen activator inhibitor (PAI) levels were studied. RESULTS: After the investigation a statistically significant decrease was found in F VIIc (P < 0.01) and F VIIag (P < 0.001) and to a lesser extent a decrease in the value of PAI. Fibrinogen and PT remained unchanged in the EG also. CONCLUSIONS: Even a short period of moderate beer consumption results in a decrease in thrombogenic activity. The only sensitive tests were F VIIc and F VIIag. The decrease in thrombogenic activity may be the main cause of decreased mortality in patients with CAD who consume moderate quantities of alcoholic beverages.

Asunto(s)

RESUMEN

The new application of differential scanning calorimetry (DSC) and the susceptibility of ovalbumin to alpha-chymotrypsin gave a quantitative estimation of protein denaturation in solid ovalbumin. Solid ovalbumin in granules with 11% of water was heated at 100 degrees C in closed and nonclosed ampules. In order to compare effects of size and crystal structure, two proteins (bovine albumin and gamma-globulin) were examined at similar conditions for the extent of denaturation. Ovalbumin and bovine albumin showed similar extents of denaturation, but gamma-globulin, with a very different molecular mass, showed the maximal conformational changes. The enthalpy of denaturation was measured to elucidate the conformational changes in solid proteins. Its value was used for calculation of the degree of denaturation. The thermodynamic data associated with transition were calculated and the number of bonds broken during denaturation was determined. Intrinsic fluorescence was utilized in order to compare these two methods. Moreover, X-ray diffraction and FTIR spectrometry were applied to native and denatured proteins.

Asunto(s)

RESUMEN

The effects of ovalbumin (OVA) denaturation using urea, guanidinium chloride (GdnHCl), sodium dodecyl sulphate (SDS), cetylpyridinium chloride (CPC), 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS), and 5 different cationic detergents with various side chains, HCl, and CH3COOH were observed. Progressive unfolding in ovalbumin was measured as a function of fluorescent light intensity, peak response and shift in the maximum of emission. Kinetic measurements demonstrated that the rate of denaturation usually followed a double exponential decay pattern, but at small concentrations of urea and acids first-order reaction was indicated. The reversibility of the unfolding-folding transitions was confirmed from tryptophan fluorescence and circular dichroism (CD) measurements. Differences in secondary structure were observed and changes of alpha-helical content were calculated. Polyacrylamide gel electrophoresis (PAGE) with and without sodium dodecyl sulphate (SDS-PAGE) showed differences in the structure of native and denatured ovalbumin. Native protein samples in PAGE demonstrated smaller number and larger mobilities of subunits than denatured ones with different reductants, such as SDS and 2-mercaptoethanol (2 ME). Scanning of SDS protein patterns showed the appearance of aggregated forms in region of 45 kD.

Asunto(s)