Increased red blood cell alloimmunization rates in transfused aplastic anemia and myelofibrosis patients.

BACKGROUND: Red blood cell (RBC) alloimmunization (AI) is a well-known complication of RBC transfusions, which results in the formation of alloantibodies to non-self antigens on donor RBCs, putting patients at risk of transfusion-related complications. The rate of AI with RBC transfusions in the general hospitalized population is estimated to be 2%-3%. However, some patients who are deemed "transfusion-dependent" require regular transfusions of blood products due to persistently low cell counts, putting them at even greater risk of RBC AI and increased morbidity. However, few studies currently exist investigating RBC AI in some transfusion-dependent patient populations, e.g., aplastic anemia (AA) and myelofibrosis (MF). STUDY DESIGN AND METHODS: We conducted a 5-year retrospective review to investigate the prevalence of RBC AI, alloantibody incidence, and the number of RBC transfusions in AA and MF patients, who received RBC transfusions within our hospital system. RESULTS: During the study period, 64 AA and 93 MF patients received 1301 and 2766 RBC transfusions, respectively. Compared to the RBC AI rate in the generalized hospitalized patient population (1%-2%), patients with AA and MF had an increased rate of RBC AI incidence rate at 14.1% and 12.9%, respectively. Furthermore, patients with primary MF demonstrated an isolated increased RBC AI incidence rate of 13.3%. The most common alloantibodies produced were anti-E and anti-K. DISCUSSION: Within our institution, patients with AA and MF had increased incidence rates of RBC AI compared to the general hospitalized patient population and may benefit from an antigen-matched protocol to minimize AI-related complications.

[Blood management in geriatric hospitalized population]. / Épargne transfusionnelle dans la population âgée hospitalisée.

INTRODUCTION: In France, nearly 50% of patients transfused in packed red blood cells are 75 or older. The benefit of restrictive transfusion policies is no longer to be demonstrated, but the practices are still far from it. The objective of our study was to show the impact of a decision support tool on transfusion practices, specifically in a hospitalized elderly population. METHOD: A clinical decision support, validated in the improvement of practices, was created, based on the latest transfusion recommendations of 2014. Our study was interventional, monocentric, within the departments of internal medicine and geriatrics of a university hospital from February to July 2016. The clinical decision support was available for any request of transfusion of packed red blood cells for 75 years old or older patient who was hospitalized in one of these two services. RESULTS: There were 134 transfusions out of 173 for which the prescriber used our tool. Comparing 2016 with the previous two years, our tool decreased the rate of packed red blood cells delivered by 11% compared to 2014 (P<0.005), but there was no significant difference compared to 2015. It has also reduced the transfusion rate of multi-unit transfusions by 35% compared with 2014 and by 29% compared with 2015 (P<0.005). CONCLUSION: Our tool, applied specifically to the elderly, is useful to improve transfusion practices and requires to be validated on a larger scale.

Altered desaturase activities and fatty acid composition in liver microsomes of spontaneously diabetic Wistar BB rat.

We examined the activities of delta 9, delta 6 and delta 5 desaturases and fatty acid composition of liver microsomes in the insulin-dependent spontaneously diabetic adult female Wistar Bio-Breeding (BB) rat. The diabetic BB rats were subcutaneously injected with different doses of protamine zinc insulin in order to be killed in hyper-, normo- or hypo-glycemic states. Desaturase activities, which are partially inhibited by spontaneous diabetes during the normo- and hyper-glycemic periods, were similarly affected by the various insulin treatment; delta 9 desaturase activity being more depressed than the desaturase activities of either delta 6 of delta 5. Insulin treatment with 10 I.U./kg body weight twice a day for 2 days was able to restore the delta 9, delta 6 and delta 5 desaturase activities to control levels during the hypoglycemic period. The microsomal fatty acid composition of BB rats liver was not consistent with the desaturase activities, particularly delta 9 desaturase activity, during the different states of glycemia, indicating that they are not closely linked in a direct cause-effect relationship.

Evidence for insulin dependent hepatic microsomal gamma-linolenic acid chain elongation in spontaneously diabetic Wistar BB rats.

We studied hepatic microsomal gamma-linolenoyl-CoA elongation and fatty acid composition of liver microsomes in spontaneously diabetic Wistar BB rats. The liver microsomal gamma-linolenoyl-CoA elongation was decreased in diabetic Wistar BB rats during both normo- and hyperglycemic periods and restored during the hypoglycemic period following insulin treatment. These results are in agreement with our previously reported data on linoleic acid delta 6 and delta 5 desaturations and support the non-parallel relationship between the chain elongation system and the glycemia. The fatty acid composition of BB rat liver microsomes was only partially consistent with the gamma-linolenoyl-CoA elongation activity at the different periods of glycemia, probably because factors other than elongation impairments were involved in the evolution of fatty acid composition.

Metabolism of dicarboxylic acids in rat hepatocytes.

[carboxyl-14C]Dodecanedioic acid (DC12) is metabolized in hepatocytes at a rate about two thirds that of [1-14C]palmitate. Shorter dicarboxylates (sebacic (DC10), suberic (DC8), and adipic (DC6) acid) are formed, mainly DC6, less DC8 and only a little DC10. In hepatocytes from clofibrate-treated rats, more polar products account for most of the breakdown products, presumably because the beta-oxidation proceeds all the way to succinate and acetyl-CoA. [carboxyl-14C]Suberic acid (DC8) is oxidized at a rate only one fifth that of dodecanedioic acid. (+)-Decanoylcarnitine inhibits palmitate oxidation but not the oxidation of dodecanedioic acid. At low concentrations of [carboxyl-14C]dodecanedioic acid or of [1-14C]palmitate, acetylsulfanilamide is more efficiently labeled by the former. High concentrations of dodecanedioic acid inhibit palmitate oxidation and the acetylation of sulfanilamide, presumably because their CoA-esters accumulate in the cytosol. These results indicate that medium-chain dicarboxylic acids are beta-oxidized mainly in the peroxisomes.

Incorporation of delta 6- and delta 5-desaturation fatty acids in liver microsomal lipid classes of obese Zucker rats fed n - 6 or n - 3 fatty acids.

The aim of this work was to study the effect of dietary n - 6 (as borage oil) and of n - 3 (as fish oil) fatty acids on the incorporation--in liver microsomal lipid classes--of fatty acids involved in delta 6- and delta 5-desaturations in obese Zucker rats compared with their lean littermates and with Wistar control rats. We observed that body and liver weights were decreased when obese Zucker rats were fed the fish oil diet. The major part of the radioactivity was recovered, in the obese Zucker rats, into the neutral lipids and especially into the triacylglycerols, while it was recovered into the phospholipid classes, especially into phosphatidylcholine, in the two other strains. Results show, in all phenotypes, an increased alpha-linolenic acid delta 6-desaturation in PL classes when the rats were fed the fish oil diet. However, a decreased linoleic acid delta 6- and delta 5-desaturation was observed in obese Zucker rats fed the fish oil diet. The fish oil diet favours the n - 3 fatty acid biosynthesis and incorporation into liver microsomal lipid classes to the prejudice of the n - 6 fatty acid series. The fatty acid incorporation is simultaneously regulated by the genetical phenotype and dietary fatty acids.

Incorporation into liver microsomal lipids of linoleic and stearic acids and of their respective products of delta 6 and delta 9 desaturation, gamma-linolenic and oleic acids: effect of age and of blackcurrant seed oil.

The incorporation of [1-14C]linoleic and [1-14C]stearic acid and of their delta 6 and delta 9 desaturation products (gamma-linolenic and oleic acids, respectively) into different classes of lipids was studied in liver microsomes of rats in function of the diet (blackcurrant seed oil diet, containing gamma-linolenic acid, versus control diet) and in function of age (3, 6 and 9 months). After delta 6 desaturation, total radioactivity was distributed between phospholipids, especially phosphatidylcholine, and neutral lipids. The desaturation product, gamma-linolenic acid, was totally recovered in the phospholipid fraction. Blackcurrant seed oil, which decreased the rate of delta 6 desaturation in 6- and 9-month-old rats, also decreased the incorporation of radioactivity in total phospholipids, especially in phosphatidylcholine. At 6 months of age, after delta 9 desaturation, the majority of radioactivity was recovered in neutral lipids principally as oleic acid, the desaturation product. The precursor, stearic acid, was highly incorporated into phospholipids, especially in rats on a diet of blackcurrant seed oil.

Carnitine palmitoyltransferase: activation and inactivation in liver mitochondria from fed, fasted, hypo- and hyperthyroid rats.

The sensitivity of carnitine palmitoyltransferase to malonyl-CoA is lost when liver mitochondria are preincubated in a KCl-containing medium. This loss of sensitivity is slowed down in mitochondria from hypothyroid rats and accelerated in mitochondria from fasted and hyperthyroid rats. Glucagon seems to enhance the effect of fasting. The loss of sensitivity is significantly slowed down by 50-500 nM malonyl-CoA and accelerated by small amounts of palmitoyl-CoA in the preincubation medium.

The effect of dietary alpha-bromopalmitate on blood lipids in the rat.

When alpha-bromopalmitate was fed to rats for 9-30 days, the level of serum triacylglycerol increased up to 2-fold over the concentration of controls. alpha-Bromopalmitate treatment had no effect on concentration of complex lipids in liver, while the triacylglycerol level in heart was significantly enhanced. From metabolic studies using isolated hepatocytes and liver microsomes, it is suggested that the increased serum triacylglycerol level after alpha-bromopalmitate feeding is mainly due to reduced fatty acid oxidation in both liver and peripheral tissues, and to a lesser extent, to inhibited fatty acid uptake and esterification.

Elongation and desaturation of arachidonic and eicosapentaenoic acids in rat liver. Effect of clofibrate feeding.

The fatty acid elongation-desaturation ability of 5,8,11,14-eicosatetraenoic (20:4(n-6)) and 5,8,11,14,17-eicosapentaenoic (20:5(n-3)) acids was determined in both liver microsomal and light mitochondrial (rich in peroxisomes) fractions of untreated and clofibrate treated rats. The elongation and the subsequent desaturation steps were performed in the corresponding favorable media. 20:5(n-3) elongation was about 2-times more extensive than that of 20:4(n-6). Clofibrate feeding for 10 days resulted in a marked decrease in the elongation rate with the two substrates, while the delta 4 desaturation rate was increased. There were small differences in the elongation rate between the microsomal and light mitochondrial fractions, however, the relative delta 4 desaturation rate was higher in the light mitochondrial fraction than microsomes.

Evidence that liver microsomes of human neonates desaturate essential fatty acids.

delta 6- and delta 5-Desaturation of essential fatty acids of n-6 and n-3 series are required for the biosynthesis of polyunsaturated fatty acids (PUFAs), which are precursors of eicosanoids and constituents of membrane phospholipids. This pathway could be of special importance during the perinatal period, when PUFAs accretion in the central nervous system is very active. However, experimental evidence of delta 6- and delta 5-desaturase activities in man is very scarce, and no data are available for newborns. We report the delta 6- and delta 5-desaturase activities detected in human liver microsomes from three neonates who died from associated malformations. Radiochemical assays of delta 6- and delta 5-desaturase activities performed with reverse phase HPLC analysis of the products in the n-6 series ranged from 4.8-13.6 to 3.2-16.4 pmol substrate converted.min-1.mg-1 microsomal proteins, respectively. In the n-3 series delta 6-desaturase activity ranged from 5.3 to 12.8 pmol.min-1.mg-1. The relationships between enzyme activities and substrate concentrations suggest excess substrate inhibition for n-6 and not for n-3 fatty acids. These results demonstrate significant delta 6- and delta 5-desaturase activities in human liver of neonates, but this activity was lower than previously reported in adult humans and in mammals, especially rodents.

A new hypotensive polyunsaturated fatty acid dietary combination regulates oleic acid accumulation by suppression of stearoyl CoA desaturase 1 gene expression in the SHR model of genetic hypertension.

Polyunsaturated fatty acids (PUFA) are known to repress SCD-1 gene expression, key enzyme of monounsaturated fatty acid biosynthesis. Alterations of the monounsaturated/saturated fatty acids ratio have been implicated in various diseases related to the metabolic syndrome, including hypertension. We previously evidenced that lipogenesis end-products accumulated in spontaneously hypertensive rats (SHR), and that a dietary combination of n-6/n-3 PUFA had hypotensive effects. Our present objective was to test the hypothesis that these SHR liver lipid disorders might be modulated, in response to this hypotensive combination, by changes in SCD-1 expression and activity. So we studied, in hepatocytes, SCD-1 transcription by Northern blotting, as well as plasma and liver fatty acid composition by gas-liquid chromatography. Liver SCD-1 gene expression was suppressed by 50%, and in different lipid classes, relative abundance of stearic and oleic acids decreased. Consequently, the Delta9 desaturation index, calculated from the ratio of oleic vs. stearic acids, decreased. In addition, the level of circulating saturated fatty acids decreased when one of oleic acids increased. These data provided evidence that the tested hypotensive PUFA combination reverses the high monounsaturated/saturated fatty acids ratio associated to hypertension in SHR, via a regulation monounsaturated fatty acid relative abundance by repression of SCD-1 gene.

Effects of streptozotocin and dietary fructose on delta-6 desaturation in spontaneously hypertensive rat liver.

We have investigated the effects of hypertension associated with diabetes mellitus on polyunsaturated fatty acid biosynthesis. For this purpose, two rat models for these pathologies have been established: a type 1 diabetic hypertensive model obtained by streptozotocin injection to spontaneously hypertensive rat (SHR), followed or not by insulin treatment (experiment 1); a type 2 diabetic hypertensive model by feeding SHR with a fructose enriched diet (experiment 2). Liver gene expression of delta-6 desaturase (D6D), microsomal D6D activities and fatty acid composition of total lipids were estimated. In experiment 1, an increase of linoleic acid (18:2 n-6) level was observed in the streptozotocin group. D6D gene expression appeared depressed in both experimental groups. Insulin did not reverse the streptozotocin effect in SHR, as it does in insulin-dependent diabetic rats. In experiment 2, the results showed a decrease of 18:2 n-6 and of long chain products of desaturation in rats fed on fructose diet. Delta-6 n-3 desaturase activity was significantly increased, whereas gene expression tended to decrease. Feeding fructose induced a significant increase in delta-9 desaturated products, suggesting a stimulation of stearoyl-CoA desaturase. These changes in monounsaturated fatty acids strongly differ from those observed in the streptozotocin experiment, indicating that the effects on lipogenesis of hypertension linked to diabetes differ according to the type of diabetes. Then, these results indicate that the liver steatosis observed during genetic hypertension was reinforced by fructose feeding. All together, the present results showed that hypertension associated to type 1 or type 2 diabetes exacerbated the damage caused by diabetes or hypertension alone on liver lipid metabolism. The metabolic effects induced by fructose being very similar to those found in human NIDDM, SHR fed a fructose-rich diet appears to be an appropriate model for studying the consequences of the combination of hypertension and NIDDM in the metabolic syndrome diseases.

Fatty acid metabolism, pharmacological nutrients and hypertension.

The purpose of the present study was to investigate the effect of a concentrated preparation (EPA 30) containing eicosapentaenoic acid (EPA, 20:5 n-3) and docosahexaenoic acid (DHA, 22:6 n-3) on the limiting desaturation steps of the polyunsaturated fatty acid biosynthesis in spontaneously hypertensive rats (SHR). Adult SHR were divided into two groups: one group received a standard diet, and the experimental group the standard diet including 0.8% of EPA30 for 9 weeks. Blood pressure was measured at the end of the diets. The desaturase activities and fatty acid composition were determined in isolated hepatocytes. The blood pressure did not decrease in the experimental group. The desaturated products of the n-6 family (gamma-linolenic acid, 18:3 n-6 and arachidonic acid, 20:4 n-6) were lowered in the EPA30 group, when their respective substrates (18:2 n-6 and 20:3 n-6) were increased. EPA and DHA were higher in the experimental group delta 6 n-3, delta 6 n-6 and delta 5 n-6 desaturase activities were depressed approximately 20% in the EPA30 group. EPA30 being an active nutrient on the EFAs cascade, increasing the level of PG3 precursors and decreasing the level of PG2 precursors, favourable conditions have been established to reduce hypertension. The underlying mechanism related to the regulation of desaturase activities by these fatty nutrients remains to be elucidated.

Liver microsomal membrane fluidity and microsomal desaturase activities in adult spontaneously hypertensive rats.

OBJECTIVE: The purpose of the present study was to investigate liver microsomal membrane fluidity simultaneously with membrane fatty acid composition and desaturase activities in spontaneously hypertensive rats (SHR). DESIGN AND METHODS: The membrane fluidity was determined, after electron spin resonance (ESR) measurement, in SHR compared with normotensive Wistar-Kyoto (WKY) rats, by calculating the order parameter S from ESR spectra of 5-nitroxide stearate and 10-nitroxide stearate, used as spin-labelled fatty acids. Desaturase activities were measured by incubating SHR and WKY rat liver microsomes with [14C]-radiolabeled fatty acids as substrates for desaturation reactions. The fatty acid composition of liver microsomal membranes was determined by gas-liquid chromatography. RESULTS: Whereas no significant difference between S of 5-nitroxide stearate was observed for SHR and WKY rats, S of 10-nitroxide stearate was significantly lower in SHR than it was in WKY rat microsomal membrane, indicating that the core microsomal membrane fluidity was higher in SHR. Significant differences between fatty acid compositions were observed for SHR and WKY rat microsomal membranes. Delta9 and n-6 delta6 microsomal desaturase activities were significantly lower in SHR. CONCLUSION: These results suggest that the higher liver core microsomal membrane fluidity observed in SHR might be dependent on the increased proportion of mono-unsaturated fatty acids. Such observed modifications and the alterations in delta9 and n-6 delta6 desaturase activities suggest that an impaired polyunsaturated fatty acid biosynthesis is related to changes in microsomal membrane fluidity in hypertension.

5-HT3 receptor-channels coupled with Na+ influx in human T cells: role in T cell activation.

The study was conducted on a human (Jurkat) T cell line, loaded with a Na+ fluorescent probe, SBFI/AM. Serotonin and an agonist of 5-HT3 receptor-channels, 2-methyl-5HT, evoked Na+ influx, whereas the agonists of other serotonergic receptor subtypes, i.e., 5-HT1A and 5-HT1B receptors, failed to induce Na+ influx in these cells. By using 3H-BRL43694, an agonist of 5-HT3 receptor-channels, we characterized 5-HT3 lymphocyte receptors which exhibited a density (Bmax) of 300 +/- 20 fmol/10(6) cells and a Kd of 30 nM in Jurkat T cells. The T-cell 5-HT3 receptor-channel is not regulated either by the protein kinase C or by the free intracellular calcium concentrations as the agents known to activate the PKC and to induce increases in intracellular free calcium concentrations failed to influence the free intracellular Na+ concentrations, [Na+]i, in these cells. Furthermore, an increase in [Na+]i, induced by 2-methyl-5HT, via 5-HT3 receptor-channels seems to stimulate T-cell activation by facilitating the progression of T cells from S to G2/M phase of the cell cycle.

A configurationally stable alkoxy allenyl zinc reagent, en route to anti-anti vicinal amino diols.

[see reaction]. The reaction of an alkoxyallenyl zinc reagent with benzyl imines derived from lactic and mandelic acids proceeds highly diastereoselectively and leads to 2-amino-1,3-diol derivatives with an anti-anti pattern.

Lipoprotein lipase steady-state mRNA levels are lower in human omental versus subcutaneous abdominal adipose tissue.

Adipose tissue synthesizes lipoprotein lipase (LPL), which helps in the postprandial clearance of triglyceride-rich lipoproteins. Because visceral adipose tissue is generally accepted as the most important metabolic tissue, we sought to verify whether there are regional differences in the expression of LPL. Samples of adipose tissue from subcutaneous and omental fat deposits were obtained from 20 adults undergoing surgery. Total adipose tissue LPL activity was measured using a conventional radioactive substrate assay. Steady-state levels of LPL mRNA were assessed using the very sensitive RNase protection assay technique with 18S ribosomal RNA as an internal control. A correlation was demonstrated between LPL activity levels in subcutaneous and omental tissue (r = .72; P < .01) and between mRNA levels at both sites (r = .47, P = .04). LPL mRNA levels were significantly lower in omental compared with subcutaneous depots (omental v subcutaneous, 1.7 +/- 0.7 v 2.1 +/- 0.7 arbitrary units [AU] over 18S, P < .05). In paired comparisons, LPL mRNA levels in omental adipose tissue were, on average, 20% +/- 7% (range, -57% to +9.0%) lower than the levels measured in subcutaneous adipose tissue (P < .05). In conclusion, these data suggest that subcutaneous adipose tissue is a reliable surrogate of the expression (activity and mRNA) of LPL in omental adipose tissue, even though omental depots express proportionally less LPL than subcutaneous depots.

Age-related depletion of linoleic acid desaturation in liver microsomes from young spontaneously hypertensive rats.

The present study was designed to investigate the microsomal interconversion of linoleic acid (LA) into arachidonic acid (AA) in young spontaneously hypertensive rats (SHR), in relation to the pathogenesis of hypertension. Our results show lower delta 6 and delta 5 desaturase activities (the limiting steps in the bioconversion of LA into AA) in young SHR, as compared to Wistar Kyoto normotensive rats. This impairment of desaturase activities is raised when the blood pressure increases and is related to the age of animals. The fatty acid composition of liver lipids shows a lower proportion of AA and a higher proportion of LA in SHR than in normotensive rats, confirming the depletion of the enzymatic system studied. Such a loss of desaturase activity may be under the control of hormones involved in the regulation of SHR blood pressure.

Effect of sodium loading (3% NaCl) on arachidonic acid biosynthesis in rat liver microsomes.

Sodium loading increases arachidonic acid (AA) metabolism by way of the prostaglandins(PGs) from series 2. Its effect on AA biosynthesis remains unknown. The purpose of the present study was to investigate the influence of sodium loading on the fatty acid composition of liver and liver microsomes, and the liver microsomal delta-6 and delta-5 desaturations of linoleic acid (LA) into AA. We found a decrease of LA and dihomo-gamma-linolenic acid (DGLA) levels in liver total lipids of Wistar rats receiving hypernatriuretic drinking water (NaCl 3%) for 60 days. At the same time AA increased. DGLA decreased and AA increased in liver microsomal total lipids. 1(14) C-LA delta-6 desaturase and 2(14) C-DGLA delta-5 desaturase activities increased in liver microsomes. These results show that, in addition to its influence on the regulation of glomerular filtration, sodium loading is involved in the regulation of liver AA biosynthesis.