dinoprost and Hemolysis

This study aimed to determine the effect of haemolysis on plasma oxidation and nitration in sickle cell disease (SCD) patients. Blood was collected from haemoglobin (Hb)A volunteers and homozygous HbSS patients who had not received blood transfusions in the last 3 months. Haemolysis was characterised by low levels of haemoglobin and haptoglobin and high levels of reticulocyte, mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), plasma cell-free haemoglobin, bilirubin, total lactate dehydrogenase (LDH) and dominance of LDH-1 isoenzyme. Plasma 8-isoprostane, protein carbonyl and nitrotyrosine levels were measured to evaluate oxidised lipids, oxidised and nitrated proteins, respectively. Plasma nitrite-nitrate levels were also determined to assess nitric oxide (NO) production in both SCD patients and controls. Markers of haemolysis were significantly evident in SCD patients compared to controls. Plasma 8-isoprostane, protein carbonyl and nitrotyrosine levels were markedly elevated in SCD patients compared to controls. Linear regression analysis revealed a significant inverse correlation between haemoglobin and reticulocyte counts and a significant positive correlation of plasma cell-free haemoglobin with protein carbonyl and nitrotyrosine levels. The obtained data shows that increased haemolysis in SCD increases plasma protein oxidation and nitration.

Topics: Adolescent; Adult; Anemia, Sickle Cell; Bilirubin; Biomarkers; Child; Child, Preschool; Dinoprost; Erythrocyte Indices; Female; Haptoglobins; Hemoglobin A; Hemoglobin, Sickle; Hemolysis; Humans; Isoenzymes; L-Lactate Dehydrogenase; Male; Nitric Oxide; Oxidation-Reduction; Reticulocyte Count; Reticulocytes; Tyrosine

Malondialdehyde (MDA) and the F(2)-isoprostane 15(S)-8-iso-prostaglandin F(2alpha) (15(S)-8-iso-PGF(2alpha)) belong to the most frequently analyzed biomarkers of oxidative stress in basic and clinical research. The objective of the present study was to examine the effect of hemolysis on free MDA and total (free+esterified) 15(S)-8-iso-PGF(2alpha) concentrations in human plasma.. MDA and 15(S)-8-iso-PGF(2alpha) were determined by GC-MS/MS in plasma samples from venous heparinized blood drawn under resting conditions (n=22) as well as under physical exercise (n=158) in 22 healthy young subjects. In vitro, we prepared plasma samples with hemolysis degrees up to 0.8% using artificially hemolyzed, freshly obtained heparinized blood.. In some plasma samples of the exercise study both under resting and exercise conditions, clinically significant hemolysis was macroscopically visible. Both in vivo (r=0.74) and in vitro (r=0.87), we found a significant positive correlation between hemolysis degree (0-0.2%) and MDA plasma concentrations (50-250 nmol/L). Unlike in vitro (r=0.84), in vivo, 15(S)-8-iso-PGF(2alpha) and MDA plasma concentrations correlated weakly (r=0.50).. We hypothesize that free hemoglobin catalyzes the formation of MDA and 15(S)-8-iso-PGF(2alpha) from free and esterified arachidonic acid. Plasma concentrations of MDA and total 15(S)-8-iso-PGF(2alpha) may be markedly compromised by hemolysis. Measurements of MDA and 15(S)-8-iso-PGF(2alpha) should be treated with caution regarding involvement of oxidative stress in disease as well as in health both under resting conditions and under exercise.

Topics: Adult; Arachidonic Acid; Biomarkers; Dinoprost; F2-Isoprostanes; Gas Chromatography-Mass Spectrometry; Hemolysis; Humans; Male; Malondialdehyde; Molecular Structure; Oxidative Stress; Vasoconstrictor Agents

Pulsatile release of uterine prostaglandin F2alpha (PGF2alpha) induces luteolysis in ruminants. However, the mechanism(s) that initiates and maintains luteolysis has not been defined. The present study tested the hypothesis that the endogenous PGF2alpha pulse generator is uterine-derived platelet-activating factor (PAF). Ovariectomized ewes were given exogenous progesterone (P), estradiol (E), or both (P+E, mimicking the normal luteal phase). Only ewes treated with steroids released PAF into the uterine lumen and had increased PAF:acetylhydrolase activity in the uterine lumen. Steroid treatment also influenced the capacity of the uterus to release PGF2alpha in response to exogenous PAF. PAF infusion did not affect plasma PGF2alpha metabolite (PGFM) levels in control (no steroid treatment) ewes but increased plasma PGFM levels in P+E ewes (P < 0.001) and ewes treated with P or E alone (P < 0.05). Infusion of PAF followed by or coincident with oxytocin (OT) acted in a synergistic manner to increase plasma PGFM levels. Repeated infusion of PAF into the uterus at 1-h intervals induced tachyphylaxis of the PGFM response to PAF; however, sensitivity of the uterus to PAF returned spontaneously by the 6th h. Interferon-tau (IFN-tau) inhibits pulsatile release of PGF2alpha during pregnancy to prevent luteolysis. Exogenous recombinant ovine IFN-tau (50 microgram) inhibited the uterine response to PAF alone or the combined effects of PAF and OT. These results indicate that uterine PAF fulfills many of the criteria for an endogenous PGF2alpha pulse-generator: steroid induction of PAF production and uterine responsiveness to PAF-induced release of PGF; synergistic stimulation of PAF-induced PGF release by OT; inhibition of PAF effects by IFN-tau; and PAF's ability to induce pulses of PGF with a periodicity during a period of chronic exposure of the uterus to PAF.

Topics: 1-Alkyl-2-acetylglycerophosphocholine Esterase; Animals; Dinoprost; Endometrium; Estradiol; Estrus; Female; Hemolysis; Interferon-gamma; Organ Culture Techniques; Ovariectomy; Phospholipases A; Platelet Activating Factor; Pregnancy; Progesterone; Recombinant Proteins; Sheep; Uterus

Oxidative stress is currently suggested as a mechanism underlying diabetes. The present study was designed to evaluate the oxidative stress related parameters in streptozotocin-induced diabetes in rats using different complementary approaches: susceptibility to in vitro oxidation (lipid peroxidation induction in liver homogenate, red blood cells hemolysis), blood antioxidant status (total antioxidant capacity by two approaches), and plasma isoprostane measurement, a new marker of lipid peroxidation in vivo. We have shown that induced liver thiobarbituric acid reactive substances increased after 4 weeks of diabetes, in spite of increased liver vitamin E content. Red blood cells hemolysis was significantly delayed after 4 weeks of diabetes. Plasma antioxidant capacity (AOC) tended to increase after 4 weeks of diabetes and was correlated with plasma vitamin E levels. Total antioxidant activity (TAA) significantly decreased after 1 week and a significant correlation was observed with plasma albumin levels. Plasma isoprostane (8-epiprostaglandinF2alpha) concentrations were not modified significantly 1 week or 4 weeks after the induction of diabetes. Levels of vitamin E in the diet and changes in its distribution among the body seems to play an important role in the development of oxidative stress during diabetes and its consequences.

Topics: Animals; Antioxidants; Arachidonic Acid; Diabetes Mellitus, Experimental; Dinoprost; Hemolysis; Lipid Peroxidation; Liver; Male; Oxidative Stress; Rats; Rats, Wistar; Streptozocin; Triglycerides

The hypoosmotic lysis curve of freshly collected human erythrocytes is consistent with a single Gaussian error function with a mean of 46.5 +/- 0.25 mM NaCl and a standard deviation of 5.0 +/- 0.4 mM NaCl. After extended storage of RBCs under standard blood bank conditions the lysis curve conforms to the sum of two error functions instead of a possible shift in the mean and a broadening of a single error function. Thus, two distinct sub-populations with different fragilities are present instead of a single, broadly distributed population. One population is identical to the freshly collected erythrocytes, whereas the other population consists of osmotically fragile cells. The rate of generation of the new, osmotically fragile, population of cells was used to probe the hypothesis that lipid peroxidation is responsible for the induction of membrane fragility. If it is so, then the antioxidant, tirilazad mesylate (U-74,006f), should protect against this degradation of stored erythrocytes. We found that tirilazad mesylate, at 17 microM (1.5 mol% with respect to membrane lecithin), retards significantly the formation of the osmotically fragile RBCs. Concomitantly, the concentration of free hemoglobin which accumulates during storage is markedly reduced by the drug. Since the presence of the drug also decreases the amount of F2-isoprostanes formed during the storage period, an antioxidant mechanism must be operative. These results demonstrate that tirilazad mesylate significantly decreases the number of fragile erythrocytes formed during storage in the blood bank.

Topics: Antioxidants; Blood Preservation; Dinoprost; Erythrocyte Membrane; Hemolysis; Humans; In Vitro Techniques; Osmotic Fragility; Pregnatrienes; Time Factors; Vitamin E