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PubMed2000

Fractional quantum mechanics

A path integral approach to quantum physics has been developed. Fractional path integrals over the paths of the Levy flights are defined. It is shown that if the fractality of the Brownian trajectories leads to standard quantum and statistical mechanics, then the fractality of the Levy paths leads to fractional quantum mechanics and fractional statistical mechanics. The fractional quantum and statistical mechanics have been developed via our fractional path integral approach. A fractional generalization of the Schrodinger equation has been found. A relationship between the energy and the momentum of the nonrelativistic quantum-mechanical particle has been established. The equation for the fractional plane wave function has been obtained. We have derived a free particle quantum-mechanical kernel using Fox's H function. A fractional generalization of the Heisenberg uncertainty relation has been established. Fractional statistical mechanics has been developed via the path integral approach. A fractional generalization of the motion equation for the density matrix has been found. The density matrix of a free particle has been expressed in terms of the Fox's H function. We also discuss the relationships between fractional and the well-known Feynman path integral approaches to quantum and statistical mechanics.

Journal Article↗
PubMed1982

Bone marrow reconstitution of lethally irradiated canines using autologous bone marrow fractions obtained by counterflow centrifugation-elutriation.

Canine bone marrow fractionated by counterflow centrifugation-elutriation results in three areas of nucleated cell recovery. Fraction 1 accounts for 50% of the total nucleated cells and 25-40% of the total recovered CFU-GM activity. Fraction 2 contains less than 2% of the total nucleated cells and less than 0.2% of the CFU-GM activity. Fraction 3 accounts for approximately 50% of the total nucleated cell recovery and 60-75% of the total recovered CFU-GM activity. Animal survival was not directly correlated with the levels of CFU-GM activity in the transfused fractions. Autologous infusion of these fractions into irradiated canines (9 Gy, 0.1 Gy/min) resulted in distinct survival profiles. Canines receiving autologous fraction-2 cells showed no haematological reconstitution, with death occurring on days 10-11 post-irradiation. Canines receiving autologous fraction-3 cells showed limited myeloid repopulation of both the bone marrow and peripheral blood with a mean survival time for 24 d. Canines receiving autologous fraction-1 cells showed complete haematological reconstitution after 48 d and long-term survival. The data may indicate a separation or enrichment of pluripotential stem cells (fraction 1) from committed myeloid progenitor cells (fraction 3).

Animals↗
PubMed1967

Substructure of the cytoplasmic membrane of Bacillus megaterium. I. Method for the fractionation of "Ghosts".

A method of fractionation of "ghosts" was devised to identify the chemical components of the cytoplasmic membrane. The method consists of dialyzing the "ghosts" against distilled water, and then dissolving the ghosts in dilute alkali. The ghosts were fractionated into four fractions by use of differential centrifugation. The components of each fraction were analyzed in detail. The ratio of lipid to protein and content of carbohydrate were found to be different for the four fractions. The main two fractions (fractions 2 and 3) contained several types of materials. Fraction 2, which is soluble in alkali and sedimentable at 105,000 x g, contained protein and lipid in the ratio of 2:1; ribonucleic acid was not detectable. Under the electron microscope, the ghosts appeared to have released the cell's cytoplasmic contents, but many small dense particles (about 100 A in diameter) remained adherent to the membrane surface. On the other hand, fraction 2 appeared to be made up only of a membrane structure. No 100 A particles were visible in this fraction. From these results, fraction 2 seemed to be pure membrane material.

Bacillus megaterium↗
PubMed1981

Effect of oral propranolol on rest and exercise left ventricular ejection fraction, volumes, and segmental wall motion in patients with angina pectoris. Assessment with equilibrium gated blood pool imaging.

The effect of oral propranolol on left ventricular ejection fraction, left ventricular volumes, cardiac output, and segmental wall motion was assessed with multigated blood pool imaging both at rest and during supine exercise in 15 patients with angina pectoris. Propranolol had no effect on resting left ventricular ejection fractions. Before propranolol, they did not change during exercise, whereas after propranolol the ejection fractions increased slightly. Exercise left ventricular ejection fractions increased with propranolol in three patients with resting left ventricular ejection fractions of less than 40 per cent. More specifically, left ventricular end-diastolic volume index, end-systolic volume index, stroke volume index, and cardiac index were not altered significantly at rest or during exercise by propranolol. Exercise left ventricular ejection fractions were increased in five and unchanged in eight patients by propranolol. Those patients with increases in left ventricular ejection fractions had a greater change in left ventricular end-diastolic volume indices and a greater change in left ventricular end-systolic volume indices during exercise while on propranolol. Left ventricular segmental wall motion was not altered significantly during exercise by propranolol. We conclude that: (1) Left ventricular functional responses to propranolol during exercise are heterogeneous and not easily predicted; (2) propranolol causes no consistent deterioration in exercise left ventricular ejection fraction even in patients with resting ventricular ejection fractions less than 40 per cent; (3) increased exercise left ventricular ejection fraction with propranolol is contributed to by significant increases in end-diastolic volume during exercise; and (4) gated blood pool imaging is a useful method for characterising rest and exercise left ventricular ejection fractions and left ventricular volumes during propranolol therapy.

Adult↗
PubMed2004

Fractionated stereotactic radiotherapy for the treatment of large arteriovenous malformations with or without previous partial embolization.

OBJECTIVE: Despite the success of stereotactic radiosurgery, large inoperable arteriovenous malformations (AVMs) of 14 cm(3) or more have remained largely refractory to stereotactic radiosurgery, with much lower obliteration rates. We review treatment of large AVMs either previously untreated or partially obliterated by embolization with fractionated stereotactic radiotherapy (FSR) regimens using a dedicated linear accelerator (LINAC). METHODS: Before treatment, all patients were discussed at a multidisciplinary radiosurgery board and found to be suitable for FSR. All patients were evaluated for pre-embolization. Those who had feeding pedicles amenable to glue embolization were treated. LINAC technique involved acquisition of a stereotactic angiogram in a relocatable frame that was also used for head localization during treatment. The FSR technique involved the use of six 7-Gy fractions delivered on alternate days over a 2-week period, and this was subsequently dropped to 5-Gy fractions after late complications in one of seven patients treated with 7-Gy fractions. Treatments were based exclusively on digitized biplanar stereotactic angiographic data. We used a Varian 600SR LINAC (Varian Medical Systems, Inc., Palo Alto, CA) and XKnife treatment planning software (Radionics, Inc., Burlington, MA). In most cases, one isocenter was used, and conformality was established by non-coplanar arc beam shaping and differential beam weighting. RESULTS: Thirty patients with large AVMs were treated between January 1995 and August 1998. Seven patients were treated with 42-Gy/7-Gy fractions, with one patient lost to follow-up and the remaining six with previous partial embolization. Twenty-three patients were treated with 30-Gy/5-Gy fractions, with two patients lost to follow-up and three who died as a result of unrelated causes. Of 18 evaluable patients, 8 had previous partial embolization. Mean AVM volumes at FSR treatment were 23.8 and 14.5 cm(3), respectively, for the 42-Gy/7-Gy fraction and 30-Gy/5-Gy fraction groups. After embolization, 18 patients still had AVM niduses of 14 cm(3) or more: 6 in the 7-Gy cohort and 12 in the 5-Gy cohort. For patients with at least 5-year follow-up, angiographically documented AVM obliteration rates were 83% for the 42-Gy/7-Gy fraction group, with a mean latency of 108 weeks (5 of 6 evaluable patients), and 22% for the 30-Gy/5-Gy fraction group, with an average latency of 191 weeks (4 of 18 evaluable patients) (P = 0.018). For AVMs that remained at 14 cm(3) or more after embolization (5 of 6 patients), the obliteration rate remained 80% (4 of 5 patients) for the 7-Gy cohort and dropped to 9% for the 5-Gy cohort. A cumulative hazard plot revealed a 7.2-fold greater likelihood of obliteration with the 42-Gy/7-Gy fraction protocol (P = 0.0001), which increased to a 17-fold greater likelihood for postembolization AVMs of 14 cm(3) or more (P = 0.003). CONCLUSION: FSR achieves obliteration for AVMs at a threshold dose, including large residual niduses after embolization. With significant treatment-related morbidities, further investigation warrants a need for better three-dimensional target definition with higher dose conformality.

Adult↗
PubMed1984

The chemical form of cadmium in subcellular fractions following cadmium exposure.

Wistar rats were given drinking water containing 250 ppm Cd for 12 months. After excision of the kidney and liver, the organs were subfractionated into nuclear, mitochondrial, microsomal and cytosol fractions, and the chemical forms of Cd in the subcellular fractions were examined. Although approximately 90% of the total Cd was present in the cytosol, in the form of metallothionein, 3-5% was also present in the mitochondrial fraction and 5-7% in the microsomal fraction from both organs. By Sephadex G-75 gel filtration, after solubilizing the particulate fractions with sodium deoxycholate, approximately 89% of Cd in the microsomal fraction and 94% in the mitochondrial fraction eluted with the same retention time as that of metallothionein in both liver and kidney, while the remainder was found in a high molecular weight protein fraction. The Cd that eluted with the high molecular protein fraction may be involved in dysfunction in subcellular organelles. For estimating the toxicity of Cd associated with the high molecular weight fraction, rat liver microsomes and CdCl2 were mixed with 1% of sodium deoxycholate and the protein-Cd complex produced was isolated by eluting with Sephadex G-75. This complex had a strong toxicity toward the alcohol dehydrogenase activity (SH-enzyme), and the Ki values of the Cd-protein complexes decreased with increased amount of Cd bound to the microsomal protein fraction. The above results suggest that loosely bound Cd increased in the case of higher Cd/protein and plays a toxic role in the living cells.

Alcohol Oxidoreductases↗
PubMed1999

Detection of haptoglobin in the high-density lipoprotein and the very high-density lipoprotein fractions from sera of calves with experimental pneumonia and cows with naturally occurring fatty liver.

In addition to the lipoprotein-deficient d > 1.25 fraction, haptoglobin was detected in the high-density lipoprotein (HDL) and the very high-density lipoprotein (VHDL) fractions from sera of calves with experimental pneumonia and cows with naturally occurring fatty liver. It was not found in the chylomicrons, very low-density lipoprotein and low-density lipoprotein fractions. Washing of the HDL fraction did not decrease the haptoglobin concentration. Transferrin and immunoglobulin G were immunoblotted to examine the possibility of contamination of the lipoprotein fractions by the d > 1.25 fraction. The two serum proteins were detected only in the d > 1.25 fraction, not in any lipoprotein fractions. The distribution pattern of haptoglobin in the lipoprotein fractions was distinct from that of serum albumin. Concentrations of haptoglobin in the HDL fractions from pneumonic sera were largely proportional to those in whole sera. Cholesteryl ester concentrations were decreased in sera from calves with pneumonia, as in cows with fatty liver. A protein immunologically related to hemoglobin was also detected in particular in the VHDL fractions from sera of both groups. These results suggest that haptoglobin or a complex with the hemoglobin-like protein may have a role or roles related to the lipid metabolism.

Animals↗
PubMed2001

Analysis by enzyme-linked immunosorbent assay and 2-dimensional electrophoresis of haptoglobin in the high-density lipoprotein fraction in cows.

Haptoglobin (Hp) is a hemoglobin (Hb)-binding acute-phase protein. Besides its relevance in inflammation, Hp is involved in the regulation of lipid metabolism. In cattle, in addition to the lipoprotein-deficient fraction, Hp is distributed in high-density lipoprotein (HDL) and very high-density lipoprotein (VHDL) fractions. The purpose of this study was to determine Hp concentrations in the lipoprotein fractions using an enzyme-linked immunosorbent assay (ELISA) based on the affinity with Hb, and also to detect structural differences of HDL Hp from that in the lipoprotein-deficient fraction using 2-dimensional electrophoresis. When purified Hp was used as the antigen for the ELISA, the detection limit was 7.4 ng/ml and linearity was obtained from 14.8 to 475 ng/ml. The correlation coefficient between the ELISA and single radial immunodiffusion was 0.884. The ELISA was shown to be applicable to evaluate Hp concentrations in the lipoprotein fractions. Hp concentrations in the lipoprotein fractions were in the range of 0.94 to 8.77 microg of Hp/ml (n = 4), and concentration ratios were 0.2 to 0.3% of whole serum Hp. Of the lipoprotein fractions, Hp was most abundant in HDL, moderate in VHDL and faint in chylomicrons, the very low-density lipoprotein fraction and low-density lipoprotein fraction. By 2-dimensional electrophoresis, alpha- and beta-chains of serum Hp were each separated into 5 spots, and their isoelectric point (pI) values were from 5.05 to 6.28 in the alpha-chain and from 5.92 to 6.95 in the beta-chain. The pI values of HDL Hp were indistinguishable from those of serum Hp. These results indicate that the ELISA based on the affinity with Hb is useful for evaluating Hp concentrations in lipoprotein fractions, and also suggest that HDL Hp is structurally similar to that in the lipoprotein-deficient fraction.

Animals↗
PubMed1990

Thermodilution right ventricular ejection fraction. Catheter positioning effects.

Right ventricular (RV) ejection fractions have been difficult to estimate clinically. It has been demonstrated recently that RV ejection fractions can be calculated by thermodilution techniques using a rapid response thermistor and computer. This method critically depends on adequate mixing of the thermal bolus and sensing of the rapid response thermistor. This study examined the effects of the thermistor position within the pulmonary artery and injectate site within the right atrium on RV thermodilution ejection fraction measurements. Ten pigs were instrumented with a RV thermodilution catheter in the pulmonary artery, an injectate catheter in the right atrium, an atrial-pacing electrode, and a systemic arterial catheter. The RV ejection fractions were determined using thermodilution in two ways: (1) with incremental increases in pulmonic valve to thermistor distance, and (2) with incremental increases in injectate port to tricuspid valve. These measurements were obtained at a paced rate of 107 +/- 1 beats per minute (bpm) and then repeated with pacing-induced tachycardia (140 bpm). The highest RV ejection fraction with the lowest coefficient of variation was with the thermistor 2 cm from the pulmonic valve (50 +/- 2 percent), with a significant decline from this value at 10 cm (42 +/- 4 percent, p less than 0.05). This reduction in RV ejection fraction values with increased pulmonic valve to thermistor distance became more pronounced with tachycardia where a significant decline in RV ejection fraction occurred at 4 cm from the valve when compared with 0 cm (38 +/- 6 percent vs 47 +/- 3 percent, respectively, p less than 0.05). There was no significant change in RV ejection fraction at any injectate port to tricuspid valve distance at the lower heart rate. With tachycardia, however, a significant decline in RV ejection fraction occurred with the injectate port located 7 cm from the tricuspid valve (p less than 0.05). These results demonstrate that RV ejection fractions can be reliably obtained using thermodilution. Positioning of the thermodilution catheter is an important consideration for obtaining optimal RV ejection fraction measurements. Care should be taken to position the catheter with the thermistor a minimal distance from the pulmonic valve and the injectate port within the central body of the right atrium.

Animals↗
PubMed2004

Fractional calculus in bioengineering, part 2.

Fractional calculus (integral and differential operations of noninteger order) is not often used to model biological systems. Although the basic mathematical ideas were developed long ago by the mathematicians Leibniz (1695), Liouville (1834), Riemann (1892), and others and brought to the attention of the engineering world by Oliver Heaviside in the 1890s, it was not until 1974 that the first book on the topic was published by Oldham and Spanier. Recent monographs and symposia proceedings have highlighted the application of fractional calculus in physics, continuum mechanics, signal processing, and electromagnetics, but with few examples of applications in bioengineering. This is surprising because the methods of fractional calculus, when defined as a Laplace or Fourier convolution product, are suitable for solving many problems in biomedical research. For example, early studies by Cole (1933) and Hodgkin (1946) of the electrical properties of nerve cell membranes and the propagation of electrical signals are well characterized by differential equations of fractional order. The solution involves a generalization of the exponential function to the Mittag-Leffler function, which provides a better fit to the observed cell membrane data. A parallel application of fractional derivatives to viscoelastic materials establishes, in a natural way, hereditary integrals and the power law (Nutting/Scott Blair) stress-strain relationship for modeling biomaterials. In this review, I will introduce the idea of fractional operations by following the original approach of Heaviside, demonstrate the basic operations of fractional calculus on well-behaved functions (step, ramp, pulse, sinusoid) of engineering interest, and give specific examples from electrochemistry, physics, bioengineering, and biophysics. The fractional derivative accurately describes natural phenomena that occur in such common engineering problems as heat transfer, electrode/electrolyte behavior, and sub-threshold nerve propagation. By expanding the range of mathematical operations to include fractional calculus, we can develop new and potentially useful functional relationships for modeling complex biological systems in a direct and rigorous manner. In Part 1 of this review (Crit Rev Biomed Eng 2004; 32(1):1-104), the fundamental properties of fractional calculus were introduced. The reader should refer to that material, particularly the sections on special functions and fractional order differential equations, for background.

Action Potentials↗
PubMedDate not supplied

Regurgitant fraction measured by using the proximal isovelocity surface area method in dogs with chronic myxomatous mitral valve disease.

Previous studies have demonstrated that regurgitant fraction can be measured by using the proximal isovelocity surface area (PISA) method. For this study, we utilized this Doppler echocardiographic method to estimate the magnitude of mitral regurgitation in dogs with myxomatous mitral valve disease. Seventeen older, small dogs with chronic mitral regurgitation and no to mild myocardial failure were studied. A blinded observer judged the clinical severity of mitral regurgitation to be mild, moderate, or severe by using echocardiographic assessment of left heart size. The regurgitant fraction was calculated by using the PISA method and spectral Doppler echocardiography. The regurgitant fraction was compared to the clinical assessment of severity for each dog and to calculations of left atrial size. Five dogs had clinically mild mitral regurgitation. Four of these dogs had a regurgitant fraction between 22 and 41%, whereas 1 had a regurgitant fraction of 73%. The 3 dogs with clinical evidence of moderate mitral regurgitation had a regurgitant fraction of 46-65%. All 9 dogs with clinically severe mitral regurgitation had a regurgitant fraction greater than 75% (78-88%). The regurgitant fraction was statistically different between each group (P < .001). A good but curvilinear relationship was found between left atrial size and regurgitant fraction (r2 = 0.72). In this study, dogs with clinically severe mitral regurgitation consistently had hemodynamically severe regurgitation (regurgitant fraction > 75%), whereas dogs with clinically mild to moderate disease had lesser degrees of regurgitation. Good correlation was found between regurgitant fraction and left atrial size. We conclude that the major determinant of left atrial size and disease severity in dogs with mitrial regurgitation is the degree of mitral regurgitation.

Animals↗
PubMed1997

Estimation of the left ventricular ejection fraction using a novel multiphase, dark-blood, breath-hold MR imaging technique.

OBJECTIVE: In this paper, we evaluate a recently proposed dual-phase dark-blood MR sequence for estimating the left ventricular ejection fraction, compare Simpson's method of estimation of ejection fraction with a model based on the biplane method, assess the reproducibility of both methods, and finally, test a semiautomated method for contouring the endocardial border. SUBJECTS AND METHODS: An MR pulse sequence was implemented to acquire cardiac images in both diastolic and systolic phases within a single breath-hold. A special magnetization preparation scheme rendered blood dark while a segmented acquisition allowed breath-hold scan times. Five healthy volunteers and five patients with cardiac disease were imaged. Ejection fractions were estimated using (1) long-axis and four-chamber biplane views with an ellipsoid model and (2) a series of short-axis views in combination with Simpson's model. These values of ejection fractions were then compared with values obtained from echocardiography. RESULTS: Estimates of ejection fractions obtained using biplane ellipsoid volume and Simpson's rule methods varied by 14% in healthy volunteers. However, for patients with severe cardiomyopathy, differences between the values of ejection fraction obtained with the two methods varied by as much as 150%. Ejection fraction estimates obtained from MR images with the biplane ellipsoid method and from echocardiography varied by approximately 14% for all subjects. Ejection fraction estimates obtained with the semiautomated algorithm agreed well with estimates obtained with manual contours made by experienced radiologists. Intraobserver variability was low for both the short-axis (3%) and biplane (4%) methods. However, interobserver variability of the biplane method (12%) exceeded that of the short-axis method (4%). Interexamination variability (9%) was the largest factor in determining the reproducibility of the ejection fraction estimates. CONCLUSION: Breath-hold dark-blood MR imaging technique with simultaneous acquisition of a series of short-axis views during systolic and diastolic phases permits rapid and accurate estimates of ejection fractions in healthy subjects and in patients. Model based biplane MR imaging methods are less reliable in patients with global cardiomyopathy. The estimation of ejection fractions can be automated using the proposed contouring algorithm and the dark-blood short-axis views.

Adult↗
PubMed2002

Immunomodulating effects of peptidic fractions issued from milk fermented with Lactobacillus helveticus.

The effect of peptides released during the fermentation of milk on the humoral immune system and on fibrosarcoma growth was studied. Lactobacillus helveticus was able to release peptidic compounds during milk fermentation due to its high proteolytic activity, as was shown by the degree of proteolysis and size-exclusion HPLC elution profiles. Three fractions of these compounds were separated and fed to mice during different periods (2, 5, and 7 d). The humoral immune response was assessed by following the number of IgA-secreting cells, and the antitumor activity was monitored by studying the regression of subcutaneously implanted fibrosarcomas. Feeding during 2 and 7 d with the medium-sized fraction (Fraction II) significantly increased the IgA-producing cells in the intestines, whereas feeding with the large compound fraction (Fraction I) during 5 d and the small compound fraction (Fraction III) during all three feeding periods provided similar increases. A double dose of Fraction II showed the highest IgA-producing cell count. The increase by Fraction III was shown to be caused by the presence of L-Tryptophan. Fraction II significantly decreased the size of fibrosarcoma when previously fed during 7 d, and feeding with Fraction I during 5 d decreased significantly its size after 35 d of growth. Although the mechanisms by which lactic acid bacteria enhance the immune system are not clear, this study clearly shows that bioactive compounds released in fermented milks contribute to the immunoenhancing and antitumor properties of these products. The release of bioactive peptides by lactic acid bacteria can have important implications on the modulation of the cellular immune response.

Adjuvants, Immunologic↗
PubMed1992

Performance of selected milk fat fractions in cold-spreadable butter.

Based on solid fat content profiles, milk fat fractions produced by fractional crystallization procedures employing melted milk fat and milk fat dissolved in acetone were selected for incorporation into soft butter samples. Butter samples made from low melting liquid fractions or a combination of primarily low melting liquid fractions and a small amount of high melting solid fractions exhibited good spreadability at refrigerator temperature (4 degrees C) but were almost melted at room temperature (21 degrees C). Butters made with a high proportion of low melting liquid fraction, a small proportion of high melting solid, and a small proportion of very high melting solid fractions were still spreadable at refrigerator temperature and maintained their physical form at room temperature. Very high melting fractions, which provided key structural functionality in spreadable butter, were obtained from acetone fractionation. Because the use of acetone in processing may hinder or prevent commercialization of these fractions, other means to obtain very high melting fractions from milk fat should be pursued.

Animals↗
PubMed1977

[Study of 67Ga distribution in neoplasms and in liver by a cell fractionation method].

Subcellular distribution of 67Ga was quantitatively determined to evaluate the role of lysosome in accumulation of 67Ga in malignant tumor tissue and liver. The following animals and transplanted tumors were used: rats implanted with Yoshida sarcoma and hepatoma AH109A; mice implanted with Ehrlich tumor. 67Ga-citrate were injected to the rats intravenously and to the mice intraperitoneally. Ten minutes to 48 hours after the administration of 67Ga-citrate, the animal were sacrificed, and the tumor tissues and liver were excised. Subcellular fractionation of tumor tissues and livers were carried out according to the method of Hogeboom and Schneider. Radioactivity of each fraction was counted by a well type scintillation counter, and protein of each fraction was measured according to Lowry's method. In Yoshida sarcoma and Ehrlich tumor, most of the radioactivity was localized in the supernatant fraction, and small amount of radioactivity was localized in the mitochodrial fraction (lysosome contains in this fraction). But in the liver, most of the radioactivity was concentrated in the mitochondrial fraction and the radioactivity of this fraction was increased with the passage of time after administration. Twenty-four hours later, about 50% of total radioactivity was accumulated in this fraction. In the case of hepatoma AH109A, radioactivity of mitochondrial fraction was increased with the passage of time after administration, and about 30% of total activity was concentrated in this fraction at 24 hours after administration. From these results it is concluded that lysosome doses not play an important role in the tumor concentration of 67Ga and lysosome plays an important role in the liver concentration of 67Ga. In the case of hepatoma AH109A it is presumed that lysosome plays considerably important role in the tumor concentration of 67Ga, hepatoma AH109A having some nature of liver.

Animals↗
PubMed2001

Effects of de-alcoholated red wine and its phenolic fractions on platelet aggregation.

BACKGROUND AND AIM: Platelet aggregation is involved in atherosclerosis and pharmacological inhibition of platelet activity may reduce the risk of coronary thrombosis and myocardial infarction. Red wine polyphenols may reduce platelet aggregability. This study evaluates the effect of de-alcoholated red wine (DRW) and its phenolic fractions on rat platelet aggregation and cyclic AMP (c-AMP) content. METHODS AND RESULTS: DRW was fractionated into four classes of phenolic compounds: phenolic acids (fraction 1), procyanidins, catechins and monomeric anthocyanidins (fraction 2), flavonols and resveratrol (fraction 3) and polymeric anthocyanidins (fraction 4). The effect of each fraction on ADP-induced rat platelet aggregation and c-AMP content was compared with that of DRW and pure phenolic compounds (quercetin, catechin, resveratrol, caffeic acid). DRW completely inhibited ADP-induced platelet aggregation. Fraction 2 also showed a significant anti-aggregating activity, whereas the effects of fractions 3 and 4 and the pure phenolics were not significant. A significant increase in platelet c-AMP content was observed after the addition of DRW and fraction 2. CONCLUSIONS: Our data indicate that DRW and its catechin-anthocyanidin fraction exert a significant effect on platelet aggregation in vitro, perhaps by enhancing platelet c-AMP levels.

Animals↗
PubMed2002

[Prediction of in-stent restenosis by measurement of fractional flow reserve and the influence of diabetes mellitus].

OBJECTIVES: This study tried to predict in-stent restenosis by the measurement of fractional flow reserve and to evaluate the effect of diabetes mellitus control on the relationship between in-stent restenosis and fractional flow reserve. METHODS: Fractional flow reserve was measured in 62 patients (mean age 61 +/- 9 years, 32 with angina pectoris and 30 with myocardial infarction) after stent implantation. The patients were divided into three groups according to the value of HbA1c and fasting blood sugar (FBS): Group P (HbA1c > or = 6.5% or FBS > or = 126 mg/dl, n = 15), Group G (6.5% > HbA1c > or = 5.8% or 126 > FBS > or = 100 mg/dl, n = 12), and Group N (HbA1c < 5.8% and FBS < 100 mg/dl, n = 35). The relationship between fractional flow reserve at the end point of stent implantation and target lesion revascularization (TLR) was evaluated. RESULTS: In all patients, fractional flow reserve was 0.89 +/- 0.17 and percentage diameter stenosis was 17.6 +/- 11.6% after stent implantation. The TLR rate was 21%. Fractional flow reserve was significantly lower in patients with TLR (0.85 +/- 0.08 vs 0.91 +/- 0.06, p < 0.01). Fractional flow reserve was significantly lower in patients with TLR in Groups N and G (Group N: 0.85 +/- 0.04 vs 0.91 +/- 0.06, p < 0.05, Group G: 0.77 +/- 0.06 vs 0.91 +/- 0.05, p < 0.01). Fractional flow reserve showed no significant difference between patients with TLR and without TLR in Group P (0.85 +/- 0.10 vs 0.87 +/- 0.08, p = NS). In patients with optimal results (fractional flow reserve > or = 0.90), TLR rate was 60% in Group P, 0% in Group G and 0% in Group N. CONCLUSIONS: Fractional flow reserve after stent implantation is useful for the prediction of TLR in patients without diabetes mellitus. However, diabetic control in patients with diabetes mellitus might be attributable to TLR rather than fractional flow reserve.

Aged↗
PubMed1992

[Effect of growth rate of monolayer cells on survival after fractionated irradiation].

This study was performed to determine the effect of the growth rate of monolayer cells on survival following fractionated irradiation. HeLa and RMUG cells that had different radiosensitivities and growth rates (Do value: 2.3 vs 1.5 Gy, doubling time: 17 vs 46 hours) were irradiated with 2 Gy every day. The fractions surviving after fractionated irradiation were compared with those given single doses. The dose modifying factor for fractionated irradiation was larger in RMUG than HeLa: 1.7 and 1.2, respectively. Two clones from ADGU cells that had the same radiosensitivity but different growth rates were also given fractionated irradiation, but there was no difference in surviving fractions. When recovery following two split doses was determined in each type of cell, the results of the fractions surviving after fractionated irradiation were correlated only with recovery between split doses. These suggest that the growth rates of monolayer cells may not modify the fractions surviving after fractionated irradiation, and the monolayer cell system is not suitable for determining the effect of growth rates on survival following fractionated irradiation.

Cell Division↗