Search

Red cell aging is the result of the accumulation of oxidative damage during cytosolic extraction of membrane lipids. It has been suggested that hemoglobin is the component responsible for extracting phospholipids from erythrocyte membranes through its oxidation products. Experiments testing this hypothesis have detected the interaction between lipid and hemoglobin oxidation products. It was shown that hemoglobin oxidation products extract phospholipid from small lamellar vesicles and adsorb fatty acids. A model describing this relationship is presented.

Removal of intracellular Ca(super 2+) cations reverses the formation of echinocytosis in human erythrocytes. A labeling technique is employed to analyze the relationship between phospholipid distribution and reversible shape transformation. Calcium(super 2+) mediates lipid randomization and different mechanisms are described to explain this process.

Hydrogen peroxide (H2O2) oxidation changes the lipid network by transferring the phospholipids from erythrocyte membranes to the cytosol. H2O2 changes the cell shape and suppresses phosphatidylserine transport during the phospholipid transfer. Lipid extraction shows the association of phosphotidylserine with the H2O2-treated cytosolic cells. The oxidative activity of H2O2 is similar to that of an aminophospholipid translocator.

The configuration and grouping of donor and recipient membranes is used to study the phospholipid transfer mechanism in membranes. Differences in the activity of movement inside the membrane, in response to experimental states, such as membrane concentration and the acceptor membrane region are predicted by a kinetic model.

Alterations in cell morphology were regulated to investigate the transbilayer diffusion of the incorporated alien lipid and sonicated vesicles, comprising diheptanoyl-, dioctanoyl-, didecanoyl- or dimyristoylphosphatidylserine, were used to incubate human erythrocytes. The sustenance of phosphatidylserine asymmetry in the bilayer of the erythrocyte membrane involves the aminophospholipid transporter to a greater extent than the cytofacial lipid attaching regions.

Students of chemistry can learn from an introductory enzyme experiment related to chemistry and flatulence. The experiment is inexpensive and uses a substrate readily available from green peas and an enzyme available in the commercial product called Beano to supply alpha-galactosidase and sucrase. The liquid form of Beano is used. Analytical equipment, glucometers, that can be bought at any local pharmacy is used. Health science majors can learn about calibration curves. and some other health concepts.

Reasons for performing study The mechanisms underlying predisposition to pasture-associated laminitis remain unclear; chronic inflammation is implicated, and this may be exacerbated by physical inactivity. Objectives To determine whether exercise affects the inflammatory profile of normal and previously laminitic ponies. Study design Prospective case-control study. Methods The short (1 day) and longer term (14 days) effects of low intensity (10 min walking and 5 min trotting) exercise on plasma inflammatory marker concentrations in normal ( NL) and previously laminitic ( PL) nonobese ponies (n = 6/group) was determined. Plasma concentrations of TNF-α, serum amyloid A ( SAA), haptoglobin, insulin, adiponectin and fibrinogen were assayed by validated/standard methods. Data were analysed using a linear mixed effects model. Results Before exercise, plasma [adiponectin] was significantly (P = 0.0001) lower in PL (mean ± s.d. 2.4 ± 0.1 ng/l) than in NL (4.03 ± 0.2 ng/l), but exercise had no effect. Previous laminitis and exercise had no effect on plasma [ TNF-α] or [fibrinogen]. Serum amyloid A concentrations in all ponies were significantly (P = 0.00001) reduced after longer term exercise compared to Day 1 values. Plasma [haptoglobin] was significantly (P = 0.00001) higher in PL compared to NL on Day 1. This difference was no longer apparent after longer term exercise, such that [haptoglobin] in PL had decreased to concentrations similar to NL. Following short-term exercise, all ponies had an initial decrease in serum [insulin] immediately after exercise, followed by an increase peaking 10 min after exercise cessation, before returning to pre-exercise values. On Day 14 these fluctuations were significantly (P = 0.001) reduced in all ponies. Conclusions Fourteen days of low intensity exercise significantly decreased [ SAA] in all ponies and plasma [haptoglobin] in PL such that it was no longer increased compared to NL. Regular low intensity exercise appears to have an anti-inflammatory effect, which is possibly greater in PL and so may be beneficial in reducing this putative risk factor in pasture-associated laminitis. [ABSTRACT FROM AUTHOR]

Reasons for performing study The mechanisms underlying individual animal predisposition to pasture-associated laminitis remain unclear; however, chronic inflammation is implicated. Objectives To identify differences in the inflammatory profile of a group of previously laminitic ponies compared with control animals at pasture in late spring and winter. Methods Previously laminitic ( PL; n = 38 and 42) and nonlaminitic control ponies ( NL; n = 41 and 39) were sampled in late spring and winter. Body condition score, height, weight and crest height and thickness were measured. Plasma concentrations of tumour necrosis factor-α, serum amyloid A, haptoglobin, insulin, adiponectin, triglyceride, fibrinogen, interleukin-17, interleukin-4 and interferon-γ were assayed by validated/standard methods. Factors independently associated with each cytokine were determined by multivariate analysis. Results Plasma [adiponectin] was significantly influenced by laminitis status, being lower in PL (median [interquartile range] 2.1[1.4-3.2] μg/l) than in NL ponies (3.4 [2.6-4.1] μg/l; P<0.0001). No other cytokines or inflammatory markers were associated with laminitis status. Plasma fibrinogen and serum amyloid A concentrations were significantly (P = 0.04 and P = 0.01) higher in geldings (3.5 [3.0-4.0] g/l; 2.2 [0.5-3.6] mg/l) than in mares (3.0 [3.0-4.0] g/l; 1.5 [0.4-2.1] mg/l) and significantly (P = 0.04 and P<0.001) higher in winter (3.5 [3.0-4.0] g/l; 2.5 [0.9-3.6] mg/l) than in late spring (3.0 [3.0-3.5] g/l; 1.1 [0.3-1.9] mg/l). Serum haptoglobin concentration showed the same significant (P<0.001) seasonal difference (winter 2.1 [1.6-2.6 g/l; late spring 1.8 1.4-2.4 g/l) and was significantly (P = 0.01) inversely associated with weight. Serum interleukin-4 concentration was significantly (P<0.0001) higher in winter (2.0 [1.2-3.0] ng/l) than in late spring (0.0 [0.0-0.0] ng/l). Serum insulin concentration was significantly (P = 0.02) influenced by season (winter 31.7 [9.6-43.5] miu/l; late spring 84.0 [7.0-131.0] miu/l). Plasma triglyceride concentration was significantly (P = 0.02) higher in PL (0.5 [0.3-0.7] mmol/l) than in NL ponies (0.4 [0.2-0.5] mmol/l). Conclusions There were significant effects of season, gender and bodyweight on a number of proinflammatory mediators or markers of inflammation. The only marker influenced by laminitis status was adiponectin, and concentrations of this anti-inflammatory marker were lower in previously laminitic animals. Potential relevance Recurrent laminitis may be associated with reduced anti-inflammatory capacity rather than a proinflammatory state. [ABSTRACT FROM AUTHOR]

Although alcohol consumption is involved in most acts of violence, most people do not become violent when they drink. Individuals also respond differently to alcohol on laboratory measures of aggression. The objective of this study was to determine whether individual differences in the effects of alcohol on a laboratory measure of aggression are related to specific personality traits and/or serotonin function, as measured by prolactin response to pharmacochallenge. Psychometric scales for impulsiveness, aggression, and anger, as well as a probe for suspiciousness, were administered to 10 healthy male social drinkers. Trait serotonin function was determined by citalopram challenge. The effect of alcohol on the Point Subtraction Aggression Paradigm was determined by comparing aggression scores with and without 1 g/kg alcohol. Impulsivity scores were significantly correlated with the change in aggressive responding after alcohol. Aggression, anger, and suspiciousness scores were not. Prolactin response did not predict the effect of alcohol on aggressive responding. The results suggest that trait impulsiveness may mediate the effects of alcohol on aggression in normal males. [ABSTRACT FROM AUTHOR]

The interaction of carbonmonoxyhemoglobin and heme with small unilamellar phospholipid vesicles was studied using dynamic light scattering. Addition of carbonmonoxyhemoglobin to dimyristoylphosphatidylcholine:dimyristoylphosphatidylserine small unilamellar vesicles resulted in an increase of average vesicle size from 17.4 to 32.0 nm. Addition of heme to vesicles produced a smaller size increase, from 17.4 to 21.0 nm. Also reported is a method for preparing small unilamellar lipid vesicles of a uniform size, suitable for use in NMR spectroscopy. [Copyright &y& Elsevier]

BSTRACT: The objectives of this paper were to test the ability of various design storm distributions to simulate the actual rainfall pattern and to compare the runoff rates used in the design of stormwater management devices in the State of Florida using continuous simulation approach. The analyses were performed for four gaged stations to evaluate the applicability of design storm distributions in different parts of the State of Florida. The approach used in this study compared the peak runoff rates from design storms based on the various distributions to those that would result from actual rainfall events. A series of continuous runoff rates were developed through the use of actual fifteen-minute recorded rainfall data, Horton type infiltration decay and recovery rate, and a continuous simulation model. The runoff rates were analyzed using frequency distributions to obtain peak runoff rates associated with different return periods based on the assumption that the continuous simulation approach closely predicts the actual runoff rates from the gaged stations. The results show that the behavior of the design storm distributions varies for different watershed characteristics in different parts of the state. The study also suggests that in general the Florida Department of Transportation and the Suwanne River Water Management (FDOT/ SRWMD) distributions appeared to agree with the continuous simulation results. [ABSTRACT FROM AUTHOR]

Studies the mechanism of phospholipid transfer between membranes as a function of the configuration and concentration of donor and recipient membranes. Effects of membrane proximity on phospholipid transfer; Factors influencing the kinetics of intermembrane transfer; Contributing factors of through-solution and collisional transfer.

The interactions of carbonmonoxyhemoglobin (HbCO), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and polyhistidine with phospholipid monolayers at the air–water interface were studied at physiological pH and ionic strength. HbCO and GAPDH both interact more strongly with monolayers containing negatively charged lipids. The interaction of HbCO and GAPDH with lipid monolayers decreases with increasing pH. Both the HbCO–monolayer and the GAPDH–monolayer interactions can be modeled as diffusion-limited processes, with kinetic data fit to a stretched exponential equation. The significance of these kinetics are discussed. Polyhistidine interacts only with monolayers containing lipids with negatively charged headgroups. In total, the results presented are consistent with an HbCO–lipid interaction with a large electrostatic component, a GAPDH–lipid interaction with comparable electrostatic and hydrophobic components, and a polyhistidine–lipid interaction that is solely electrostatic. [Copyright &y& Elsevier]

Chlorpromazine (CPZ), an antipsychotic agent shown to inhibit the action of various neurophysiological receptors, also exhibits preferential association with the plasma membrane, inducing stomatocytic morphological response in red blood cells (RBC). Given the cationic nature of CPZ, fluorimetry, pH titration, and red cell morphological studies were performed to assess the associative predilection of CPZ for anionic membrane components. CPZ fluorescence intensity increased 320–370% upon addition of phosphatidylcholine (PC) small unilamellar vesicles (SUVs) to aqueous CPZ, indicating an affinity of the drug for lipidic phases. After removal of unbound drug, CPZ fluorescence increased up to 92% with increasing phosphatidylserine (PS) in the lipid phase (up to 30 mol% of total lipid), suggesting a preferential association of the drug with anionic lipids. In studies of pH titration, the pKa of CPZ in the presence of Triton X-100 micelles or phospholipid SUVs increased with increasing anionicity of the lipidic phase [7.8 with Triton X-100, 8.0 with PC, 8.3 with phosphatidylglycerol (PG)], lending further support to preferential drug interaction with anionic lipidic components. At 0 °C, CPZ-induced red cell shape change was less extensive in cells made echinocytic by adenosine triphosphate (ATP) depletion, compared to cells made echinocytic by PS treatment following vanadate preincubation. This suggests that polyphosphoinositide lipids are CPZ membrane binding sites. Since polyphosphoinositide lipids are implicated as important intermediates in a number of receptor-mediated cell signaling pathways, evidence of association with these specific lipids provides a means by which psychoactive drugs may induce neurophysiological effects through direct interaction with general membrane components. [Copyright &y& Elsevier]