Membrane Lipid Profile Research Articles

MALDI reveals membrane lipid profile reversion in MDX mice

Duchenne muscular dystrophy (DMD), the most common and severe X-linked myopathy, is characterized by the lack of dystrophin, a sub-sarcolemmal protein necessary for normal muscle functions. In a previous study of the lipid content of skeletal muscles of dystrophic ( mdx) mice, the animal model for DMD, by in situ Matrix-Assisted Laser Desorption-Ionization Mass Spectrometry (MALDI-MS), an inversion of the phosphatidylcholine PC34:2/PC34:1 ion peaks intensity ratio was observed between destructured (abnormal fiber morphology) and structured (normal fiber morphology). A possible treatment for this dramatic disease is to introduce an exogenous nitric oxide (NO) donor into the organism, leading to an increase of utrophin and a regression of the dystrophic phenotype. In the present work, after confirmation by tandem mass spectrometry of the structure of these two phospholipids, their intensity ratio inversion was used to evidence a restoration of membrane lipid composition very similar to those of wild-type mice after the treatment of mdx mice with molsidomine, a NO donor. This was associated with the observation by immunohistology of an increase of the regeneration process in the mice.

Ximelagatran increases membrane fluidity and changes membrane lipid composition in primary human hepatocytes

Ximelagatran, the first oral agent in the new class of direct thrombin inhibitors, was withdrawn from the market due to a potential risk of severe liver injury. Increased rates of liver enzyme elevations had been observed during clinical trials of chronic use. Despite intensive preclinical investigations the cellular mechanisms behind the observed hepatic effects remain unknown. The aim of this study was to investigate whether ximelagatran has an effect on the plasma membrane fluidity and the membrane lipid composition which may be important for the cell integrity. After 1 h exposure of primary human hepatocytes with 10 or 100 μM ximelagatran, a significant elevation of membrane fluidity was observed. This elevation was maintained at 24 h, but diminished at 48 h exposure. As changed membrane lipid composition could influence membrane fluidities, changes in membrane lipid profiles were also studied. After 1 h exposure, the phosphatidylcholine/phosphatidylethanolamine molar ratio decreased, whereas the total cholesterol/phospholipid molar ratio decreased after a 48 h exposure. The change in membrane fluidity and lipid composition in human hepatocytes exposed to ximelagatran might indicate changes in plasma membrane properties that in susceptible subjects, could result in loss of membrane integrity and leakage of cellular proteins.

Effects of lithium on membrane fluidity and lipid profile in brain membranes of aluminum-treated rats

The effects of lithium (Li) supplementation on lipid profile and fluidity of cerebrum and cerebellum membranes in aluminum (Al)-treated rats were investigated. A significant decrease in the levels of total lipids and cholesterol was observed in both the regions following Al exposure, which however were significantly increased following Li supplementation. Further, glycolipids and gangliosides contents were significantly decreased in cerebrum, but increased in cerebellum following Al treatment. Interestingly, Li supplementation reversed the trends and regulated the levels of glycolipids and gangliosides. Al treatment also elevated conjugated diene formation and phospholipid levels in both cerebrum and cerebellum membranes, which however were decreased upon Li supplementation. The cholesterol/phospholipid ratio however was decreased after Al treatment and Li supplementation was able to enhance the ratio in both cerebrum and cerebellum. Further, Al treatment significantly increased the fluorescence polarization, anisotropy and order parameter, which however were normalized following Li supplementation. The levels of Al were also found to be significantly elevated in cerebrum and cerebellum after Al treatment and normalized in cerebellum following Li treatment. Therefore, the present study shows the potential of Li in regulating the changes produced by Al on membrane composition and fluidity in rat brain.

Modulation of plasma membrane lipid profile and microdomains by H 2O 2 in Saccharomyces cerevisiae

In Saccharomyces cerevisiae, the rate of hydrogen peroxide (H 2O 2) diffusion through the plasma membrane decreases during adaptation to H 2O 2 by a still unknown mechanism. Here, adaptation to H 2O 2 was observed to modulate rapidly the expression of genes coding for enzymes involved in ergosterol and lipid metabolism. Adaptation to H 2O 2 also alters plasma membrane lipid composition. The main changes were the following: (a) there was a decrease in oleic acid (30%) and in the ratio between unsaturated and saturated long-chain fatty acids; (b) the phosphatidylcholine:phosphatidylethanolamine ratio increased threefold; (c) sterol levels were unaltered but there was an increased heterogeneity of sterol-rich microdomains and increased ordered domains; (d) the levels of the sterol precursor squalene increased twofold, in agreement with ERG1 gene down-regulation; and (e) C26:0 became the major very long chain fatty acid owing to an 80% decrease in 2-hydroxy-C26:0 levels and a 50% decrease in C20:0 levels, probably related to the down-regulation of fatty acid elongation ( FAS1, FEN1, SUR4) and ceramide synthase ( LIP1, LAC1) genes. Therefore, H 2O 2 leads to a reorganization of the plasma membrane microdomains, which may explain the lower permeability to H 2O 2, and emerges as an important regulator of lipid metabolism and plasma membrane lipid composition.

Regulation of Fatty Acid Metabolism by FadR Is Essential for Vibrio vulnificus To Cause Infection of Mice

The opportunistic bacterial pathogen Vibrio vulnificus causes severe wound infection and fatal septicemia. We used alkaline phosphatase insertion mutagenesis in a clinical isolate of V. vulnificus to find genes necessary for virulence, and we identified fadR, which encodes a regulator of fatty acid metabolism. The fadR::mini-Tn5Km2phoA mutant was highly attenuated in a subcutaneously inoculated iron dextran-treated mouse model of V. vulnificus disease, was hypersensitive to the fatty acid synthase inhibitor cerulenin, showed aberrant expression of fatty acid biosynthetic (fab) genes and fatty acid oxidative (fad) genes, produced smaller colonies on agar media, and grew slower in rich broth than did the wild-type parent. Deletion of fadR essentially recapitulated the phenotypes of the insertion mutant, and the DeltafadR mutation was complemented in trans with the wild-type gene. Further characterization of the DeltafadR mutant showed that it was not generally hypersensitive to envelope stresses but had decreased motility and showed an altered membrane lipid profile compared to that of the wild type. Supplementation of broth with the unsaturated fatty acid oleate restored wild-type growth in vitro, and infection with oleate in the inoculum increased the ability of the DeltafadR mutant to infect mice. We conclude that fadR and regulation of fatty acid metabolism are essential for V. vulnificus to be able to cause disease in mammalian hosts.

Alterations in the Lipid Profile and Membrane Dynamics of Rat Intestinal Brush Border Membrane Induced by Different Classes of Nonsteroidal Anti-Inflammatory Drugs

ABSTRACTNonsteroidal anti-inflammatory drugs (NSAIDs) are known to cause gastrointestinal damage. New anti-inflammatory drugs have been developed in an attempt to improve their gastrointestinal side effect profile. Therefore, the objective of the present study was to compare the effect of three different NSAIDs, aspirin, nimesulide, and celecoxib, on the lipid profile and dynamics of rat intestinal brush border membranes (BBMs). Female Wistar rats were divided into four different groups viz: group I (control), group II (aspirin treated), group III (nimesulide treated), and group IV (celecoxib treated). Groups II, III, and IV received the corresponding drugs orally at a dose of 40 mg/kg body weight dissolved in water, while the control group received the vehicle only. After 28 days, all the treatment groups showed modification in the lipid profile of intestinal BBM as compared to control. Alterations in the intestinal membrane dynamics by fluidity studies showed a considerable increase, which correlated well with the changes in the lipid composition. It was suggested that NSAIDs such as aspirin, nimesulide, and celecoxib pose intestinal side effects due to initial changes in the composition and dynamics of the membranes. It was further concluded that newly discovered NSAIDs such as celecoxib have better safety profiles because of the less intense membrane effects, but studies are still required to comment decisively on the suitability of various NSAIDs depending upon their cyclooxygenase enzyme specificity.

Docosahexaenoic acid facilitates cell maturation and β-adrenergic transmission in astrocytes

The effects of docosahexaenoic acid (DHA; 22:6 n-3), a major omega-3 PUFA in the mammalian brain, on the structure and function of astrocytes were studied using primary cultures from rat cerebra. Gas-liquid chromatography of methyl esters of FAs isolated from cultures exposed to individual FAs, namely, stearic acid, linoleic acid, arachidonic acid, and DHA, showed alterations in the lipid profiles of the membranes, with a preferential incorporation of the FA to which the cells were exposed. Immunofluorescence studies demonstrated that unlike treatment with other FAs, after which the astrocytes remained as immature radial forms, DHA-treated astrocytes showed distinct differentiation, having morphology comparable to those grown in normal serum-containing medium. Receptor binding studies to determine the concentration of various neurotransmitter receptors showed that DHA selectively increased the number of beta-adrenergic receptors (beta-ARs) compared with FA-untreated controls, suggesting a greater role of DHA on beta-AR expression in membranes. This was also reflected by an increase in downstream events of the beta-AR pathways, such as the induction of protein kinase A and glycogen turnover by isoproterenol (ISP), a beta-AR agonist in DHA-treated cells. Moreover, ISP completely transformed DHA-treated cells into mature astrocytes bearing long processes, as in cells grown under normal conditions. Together, our observations suggest that DHA plays a unique role in facilitating some of the vital functions of astrocytes in the developing brain.

Myofibril Membranes in Relation to the Neuromuscular Weakness of Acute Monocrotophos Poisoning

Organophosphate poisoning is a common method of deliberate self-harm in countries where the pesticides are readily available. The severity of neuroparalysis and myopathy occurring in acute organophosphate poisoned patients is determined by the severity of poisoning and is associated with morbidity and mortality. Molecular mechanisms that underlie severe paralysis are not well delineated but are essential to know to improve treatment. In this study rats were subjected to increasing doses (0.25 to 0.8 LD50) of monocrotophos, and cell membrane lipid profiles, particularly those of myofibril membranes, were examined in relation to neuromuscular weakness occurring in poisoning. Increasing doses of monocrotophos inhibited brain and RBC acetylcholinesterase ≥60% early in the poisoning. RBC acetylcholinesterase levels recovered to 70% to 80% of normal while brain acetylcholinesterase remained 44% to 67% inhibited 1 week after poisoning. Increasing severity of poisoning led to significant changes in myofibril membrane lipid composition with cholesterol to phospholipid ratios increasing from 0.029 ± 0.008 in controls to 0.063 ± 0.023 in severe poisoning (p > 0.05). These changes were associated with neuromuscular weakness in the first day of poisoning. Membrane changes were reversible and rats recovered muscle strength in 1 week with no treatment. Lipid compositions of the intestine, brain, and muscle mitochondrial membranes were not affected by monocrotophos. The study indicated that neuromuscular weakness was associated with muscle membrane disorganization early in the course of acute organophosphate poisoning and that subclinical neurotoxicity of long duration may be a consequence of acute organophosphate poisoning. Controlling the severity of poisoning early in the course of acute organophosphate poisoning appears to be important for clinical recovery.

Changes in serum and red blood cell membrane lipids in patients treated with interferon ribavirin for chronic hepatitis C

One of the side effects by interferon ribavirin (I/R) treatment is haemolytic anemia, causing some patients to discontinue I/R treatment. The exact mechanism of I/R-induced anemia is unknown. The aim of this study is to evaluate the effects of I/R treatment on the serum lipid and red blood cell (RBC) membrane lipid profiles of patients with chronic hepatitis C (CHC) and the association between changes of RBC membrane lipids and haemolytic anemia by I/R treatment. Fourteen patients with CHC were treated with I/R and their serum lipid profiles were studied. In addition, in seven of the 14 patients, the RBC membrane lipid profiles were analysed. In the RBC membrane lipid composition, the total cholesterol, total phospholipids and cholesterol/phospholipids (C/PL) ratio were significantly increased. Phosphatidylcholine (PC) and the phosphatidylcholine/ sphingomyelin (PC/SM) ratio were significantly decreased and other phospholipid fractions were significantly increased. Changes in the serum lipids and RBC membrane lipid profiles of patients with CHC treated with I/R were shown. Especially, a decrease in the RBC deformability and membrane fluidity by changes in these RBC membrane lipids was supposed and it is suggested that those changes may result in haemolytic anemia by I/R treatment.

Beneficial influence of dietary curcumin, capsaicin and garlic on erythrocyte integrity in high-fat fed rats

In rats rendered hyperlipidemic by maintaining them on a high-fat diet (30%) for 8 weeks, inclusion of spice principles [curcumin (0.2%) or capsaicin (0.015%)] or garlic (2.0%) in the diet produced significant hypotriglyceridemic effect. Plasma cholesterol remained unaffected in high-fat treatment. Hepatic triglyceride content was significantly higher in high-fat fed rats, and this increase was effectively countered by inclusion of the hypolipidemic spice agents — curcumin, capsaicin or garlic in the diet. The lipid profile of erythrocyte membranes of hyperlipidemic rats was similar to basal controls. An examination of the osmotic fragility of erythrocytes in various groups indicated that the red blood cells of hyperlipidemic rats display a slight resistance to osmotic lysis. Inclusion of spice principles [curcumin (0.2%) or capsaicin (0.015%)] or garlic (2.0%) in the diet, which produced the hypotriglyceridemic effect, appeared to beneficially correct this altered osmotic fragility of erythrocytes. Activities of ouabain-sensitive Na +,K +-ATPase as well as acetylcholinesterase of erythrocyte membranes in high-fat fed rats remained unaltered. Activity of Ca 2+,Mg 2+-ATPase in erythrocyte membrane was significantly decreased in high-fat fed animals, whereas dietary spice principles and garlic countered this reduction in enzyme activity. In the absence of any change in the cholesterol/phospholipid molar ratio in the erythrocyte membrane, a decreased activity of membrane-bound Ca 2+,Mg 2+-ATPase could have probably contributed to the accumulation of intracellular calcium leading to the diminished deformability of the erythrocytes in high-fat fed rats.

307 EFFECT OF BULL EPIDIDYMIS STORAGE CONDITIONS ON SPERM RESISTANCE AGAINST LIPID PEROXIDATION AND SUBSEQUENT IN VITRO EMBRYO PRODUCTION

Sperm recovery from the cauda epididymis can be a usefull tool in case of unexpected death of genetic high-value animals or endangered species or when the collection of sperm by other means becomes impossible. Studies indicate that the lower the temperature of epididymis storage, the better the sperm quality after collection (Kaabi et al. 2003 Theriogeneology 60, 1249-1259). One of the main factors that can negatively affect sperm viability during storage is lipid peroxidation, where sperm membrane resistance against reactive oxygen species (ROS) attacks is an important factor. The objective of this experiment was to study whether the temperature of epididymis storage following slaughter would have an influence on the membrane's resistance against lipid peroxidation and on the sperm cell's fertilizing capacity. Sixteen epididymides (from eight bulls) were collected after slaughter and divided into two groups, one stored at 4�C and the other at 37�C for 2 h, after which semen was collected from the caudae epididymides. Sperm concentration was measured and an aliquot containing 108 sperm cells was submitted to induced lipid peroxidation with ferrous sulfate and ascorbate (37�C; 2 h). Subsequently, thiobarbituric acid reactive substances (TBARS), as an index of lipid peroxidation, were measured according to a method previously described (Beorlegui et al. 1997 Andrologia 29, 37-42). A second aliquot of the sample was used for fertilization in a routine IVF-IVC set up in duplicate (24-h maturation, SOF culture medium in 5% CO2, 5% O2, and 90% N2). In vitro embryo production and level of TBARS were statistically analyzed using SAS (SAS Institute, Inc., Cary, NC, USA). TBARS levels were transformed to logarithm form in order to obey the residue normality being analyzed using PROC GLM. The percentage of blastocysts was analyzed using the Wilcoxon test. When compared to the samples stored at 4�C, semen of caudae epididymides stored at 37�C showed higher levels of TBARS and lower mean blastocyst rates (324.7 � 59.6 and 36.6 � 1.6 vs. 466.9 � 67.9 ng of TBARS/108 spermatozoa and 28.8 � 2.9%, respectively; P < 0.05). A negative correlation was found between TBARS and blastocyst rates (R = -0.43). The lower quality of sperm collected from epididymides maintained at higher temperatures may be related to a decrease in sperm resistance against lipid peroxidation which would further impair sperm fertilizing capacity. However, further studies are necessary in order to study the effect of temperature on the sperm membrane lipid profile, because the content of polyunsaturated fatty acids may be affected by temperature; this is an important factor relative to sperm membrane lipid peroxidation susceptibility (Ollero et al. 2000 Mol. Reprod. Dev. 55, 326-334). Another important factor is the epididymal environment because interactions between the sperm membrane and its surroundings can play an important role on the membrane's antioxidant protection.

Alteration in the composition of cholesteryl glucosides and other lipids in Helicobacter pylori undergoing morphological change from spiral to coccoid form

In this analysis of membrane lipid compositions in Helicobacter pylori, the membrane lipid profiles drastically changed during coccoid formation: cholesteryl-6- O-tetradecanoyl-α- d-glucopyranoside levels increased, cholesteryl-α- d-glucopyranoside and phosphatidyl ethanolamine decreased, and a coordinated increase in cardiolipin and decrease in phosphatidyl glycerol were observed. Cholesteryl-6- O-phosphatidyl-α- d-glucopyranoside was hardly detected in the spiral forms in the logarithmic phase, but subsequently increased throughout the coccoid conversion. These results suggest that environmental stresses induce the expression of certain regulatory systems for lipid metabolism in H. pylori, and that the resulting alterations in lipid composition play an important role in inducing the coccoid conversion.

Membrane lipid profile of an edible basidiomycete Lentinula edodes during growth and cell differentiation.

The basidiomycetous mushroom Lentinula edodes (Shiitake) exhibits a unique process of cell differentiation termed "fruiting-body formation". To clarify the relationship between membrane lipids and fruiting-body formation in this fungus, we investigated variations in levels of phospholipids, cerebrosides, fatty acyl residues in the major phospholipids, and fatty acyl and sphingoid base residues in cerebrosides during vegetative growth and fruiting-body formation. PC, PE, and PS were the primary phospholipids in the cells of L. edodes. After a shift in growth temperature of L. edodes mycelia has been shifted from 25 to 18 degrees C, the proportion of unsaturated FA (UFA), such as linoleic acid (18:2) and oleic acid (18:1), increased. In contrast, during fruiting-body formation induced by the temperature downshift to 18 degrees C, 18:2 of PC in the primordia and fruiting bodies decreased, and the UFA of PE and 18:1 of PC increased compared with the proportions in mycelia growing at 18 degrees C. These results showed that the proportions of fatty acyl residues in PC and PE differed during fruiting-body formation in L. edodes. Moreover, the amount of cerebrosides in primordia increased compared with those in mycelia and fruiting bodies and, in these differentiating tissues, the proportion of 2-hydroxypentadecanoic acid increased whereas that of 2-hydroxyoctadecanoic acid decreased compared with that in the mycelia. However, the proportion of sphingoid base residues in cerebrosides did not change during fruiting-body formation in L. edodes.

Variations in the lipid profile of patients with chronic renal failure, treated with folic acid.

Dyslipidemia and increases in plasma homocysteine usually occur at end-stage renal disease; both are recognized as risk factors for atherosclerosis. Folate administration reduces homocysteine concentration. In this study we determined the effect of a high dose of folic acid (40 mg intravenous injection three times a week) on plasma and red blood cell lipid profiles in twelve chronic renal failure patients on regular hemodialysis. Fasting blood samples were taken at the beginning of the study (baseline) and after 21, 42, and 64 days of treatment. Folic acid supplementation decreased plasma homocysteine. Plasma triglyceride levels decreased whereas polyunsaturated fatty acid values increased after 21 days; then they returned to baseline levels at the end of treatment. Total cholesterol and low-density lipoprotein (LDL) cholesterol were higher than those of the baseline during all the study, whereas high-density lipoprotein (HDL) cholesterol was reduced. In erythrocyte membranes, folic acid therapy enhanced cholesterol/phospholipid ratios and the fluorescence anisotropy of diphenyl-hexatriene. We conclude that large doses of folic acid produce a favorable effect, reducing plasma homocysteine levels and protecting patients from atherosclerosis. However, as this therapy induces significant alterations in both plasma and erythrocyte membrane lipid profiles, plasma lipid values should be controlled throughout the treatment of patients with renal failure.

Determination of cholesterol in erythrocyte membrane

Quantification of cholesterol in biological membranes is an important step toward understanding of metabolism of intracellular cholesterol, composition of cell membrane and plasma lipid profile. The aim of our study was to optimize the method for determination of cholesterol in erythrocyte membrane and then to use this method in the determination of cholesterol concentration in erythrocyte membrane in the studied group of blood samples. Cholesterol in erythrocyte membrane was determined in dry lipid extract of erythrocyte membrane by the enzymatic manual CHOD-PAP method. Cholesterol in erythrocyte membrane and plasma lipid parameters (total cholesterol HDL-cholesterol, LDL-cholesterol and triglycerides) were determined in blood samples of 58 females, obtained by routine health control. Lipid parameters were determined by standard biochemical methods. We examined the relationship between cholesterol in erythrocyte membrane and other plasma lipid parameters as well as other atherogenic risk factors (BMI, blood pressure). Optimization of the method for determination of cholesterol in erythrocyte membrane was based on the observation that primary cholesterol standards prepared by dissolving crystal cholesterol cannot be used due to the interference of the dissolved dry extract in organic solvents with the enzymatic reagent. Commercial standard solutions of cholesterol were used for calibration because they contain detergents for solubilisation of the dry extract in enzymatic reagent. The obtained mean value for cholesterol in erythrocyte membrane, as mmol/L erythrocyte is 4.44 ? 1.019; median 4.65 5-th percentile is 2.70, and 95-th percentile is 6.26. In the examined female group we tested cholesterol concentration in erythrocyte membrane according to age. Two groups were formed (females below and above 50 years) using nonparametric t-test no statistically significant difference was found between these two age groups (p>0.05), while plasma lipid parameters of total cholesterol, triglycerides and LDL-cholesterol were different in the examined groups (p<0.05). By Spearmen nonparametric correlation method we found no statistically significant correlation between cholesterol in erythrocyte membrane and other atherogenic risk factors.

Cellular apoptosis and organ injury in sepsis: a review.

Cellular apoptosis and organ injury in sepsis: a review.

Population growth kinetics and bulk membrane lipid alterations in Tetrahymena pyriformis: exposure to pentachlorophenol.

This study describes effects of exposure of the freshwater ciliate Tetrahymena pyriformis to the "classic" weak acid respiratory uncoupler pentachlorophenol (PCP) on the population growth kinetics and membrane lipid profiles. The assessment of growth kinetics of naive populations exposed to PCP, at concentrations eliciting < 50% growth inhibition, showed generation times of exposed cultures similar to generation times of controls but preceded by a short lag phase (< 2 h). Assessment of exposed cultures exhibiting > 50% growth inhibition revealed generation times that increased with increasing concentrations of toxicant. In addition, the relative percentages of selected fatty acid methyl esters (FAMEs) in both pellicle and mitochondrial membranes were examined. Upon exposure to PCP the relative percentages of FAMEs 12:0, 14:0, 16:0, 16:1, and 18:0 did not change. However, with exposure to PCP a decrease was observed for FAMEs 15:0 and 17:0. Conversely, with PCP exposure there was an increase in FAME 18:1. A comparison of these results with those elicited upon exposure to the model narcotic 1-octanol reveals marked differences in both growth kinetics and fatty acid shifts.

Integrity of erythrocytes of hypercholesterolemic rats during spices treatment.

In rats rendered hypercholesterolemic by maintaining them on a cholesterol-enriched diet (0.5%) for 8 weeks, inclusion of spice principles--curcumin (0.2%) or capsaicin (0.015%) or the spice--garlic powder (2.0%) in the diet, produced the expected hypolipidemic effect. Plasma cholesterol which was more than 200% that of basal control in hypercholesterolemic rats, was decreased by these dietary spice principles and garlic by 25-39%. Erythrocyte membranes of hypercholesterolemic rats were relatively enriched in cholesterol, which was about 120% of basal control, while membrane phospholipid was unaffected. This resulted in a significant alteration in cholesterol to phospholipid ratio of RBC membranes. Dietary curcumin, capsaicin and garlic were observed to counter this altered lipid profile of erythrocyte membranes in hypercholesterolemic situation by producing a significant 10-14% decrease in membrane cholesterol content. As a result of alteration in membrane structural lipids, the structural integrity of RBCs was also affected. An examination of the osmotic fragility of erythrocytes in various groups, indicated that RBCs of hypercholesterolemic rats were relatively fragile compared to normal controls. Dietary curcumin, capsaicin and garlic appeared to correct this increased fragility of erythrocytes.

Effect of mulberry ( Morus indica L.) therapy on plasma and erythrocyte membrane lipids in patients with type 2 diabetes

Background: Mulberry ( Morus indica L.) is non-toxic natural therapeutic agent shown to possess hypoglycemic, hypotensive, and diuretic properties. Methods: The hypoglycemic effect of the mulberry leaves was evaluated by comparing the anti-diabetic activity of the standard drug, glibenclamide. A total of 24 type 2 diabetic patents were divided randomly into two treatment groups: the mulberry agent and glibenclamide, for 30 days. Serum and erythrocyte membrane lipid profiles of the patients were analyzed before and after the treatments. Results: Patients with mulberry therapy significantly improved their glycemic control vs. glibenclamide treatment. The results from pre- and post-treatment analysis of blood plasma and urine samples showed that the mulberry therapy significantly decreased the concentration of serum total cholesterol (12%, p<0.01), triglycerides (16%, p<0.01), plasma free fatty acids (12%, p<0.01), LDL-cholesterol (23%, p<0.01), VLDL-cholesterol (17%, p<0.01), plasma peroxides (25%, p<0.01), urinary peroxides (55%, p<0.01), while increasing HDL-cholesterol (18%, p<0.01). Although the patients with glibenclamide treatment showed marginal improvement in glycemic control, the changes in the lipid profile were not statistically significant except for triglycerides (10%, p<0.05), plasma peroxides (15%, p<0.05), and urinary peroxides (19%, p<0.05). Both treatments displayed no apparent effect on the concentrations of the glycosylated hemoglobin (Hb A 1c) in diabetic patients. However, the fasting blood glucose concentrations of diabetic patients were significantly reduced by the mulberry therapy. Conclusions: Mulberry therapy exhibits potential hypoglycemic and hypolipidemic effects in diabetic patients.

Impairment of the ryanodine-sensitive calcium release channels in the cardiac sarcoplasmic reticulum and its underlying mechanism during the hypodynamic phase of sepsis.

Changes in Ca2+-induced Ca2+ release in cardiac sarcoplasmic reticulum (SR) during different phases of sepsis were studied. Sepsis was induced by cecal ligation and puncture (CLP). The 45Ca2+ release studies show that the amount of Ca2+ released from the passively and the actively loaded SR vesicles was unaffected during the early sepsis (9 h after CLP), but it was significantly decreased during the late phase (18 h after CLP) of sepsis. The [3H]ryanodine binding assays reveal that the Bmax for ryanodine binding was unaffected during the early phase, but was decreased by 32.1% during the late phase of sepsis. The affinity of ryanodine receptor for Ca2+ remained unchanged during sepsis. ATP, AMP-PCP, and caffeine stimulated binding, while MgCl2 and ruthenium red inhibited [3H]ryanodine binding in control, early sepsis, and late sepsis groups. The EC50 and IC50 values for these regulators were unaffected during the progression of sepsis. Digestion of control SR with phospholipase A2 decreased [3H]ryanodine binding and the decrease was reversible by the addition of phosphatidylcholine (PC), phosphatidylethanolamine (PE), or phosphatidylserine (PS). Addition of PC, PE, or PS to the SR isolated from septic rats stimulated [3H]ryanodine binding. These data demonstrate that Ca2+-induced Ca2+ release from cardiac SR remained relatively unaffected during the early phase, but was significantly impaired during the late phase of sepsis. The sepsis-induced impairment in SR Ca2+ release is a result of a quantitative reduction in the number of Ca2+ release channels. Furthermore, the reduction is associated with a mechanism involving a modification of membrane lipid profile in response to certain stimuli such as activation of phospholipase A2.