Evaluation of the antithrombotic activity of Zhi-Xiong Capsules, a Traditional Chinese Medicinal formula, via the pathway of anti-coagulation, anti-platelet activation and anti-fibrinolysis.

Zhi-Xiong Capsules (ZXC) involving Hirudo, Ligusticum chuanxiong, Salvia miltiorrhiza, Leonurus artemisia, and Pueraria lobata, is an empirical prescription used in Chinese clinics applied for treating cerebral arteriosclerosis and blood-stasis in clinic. However, the mechanism of its antithrombotic activity has not been investigated until now. The present study was designed to investigate its antithrombotic effects, the mechanism of ZXC on anti-thrombus action and to identify the main chemical composition of ZXC using HPLC-DAD-ESI-IT-TOF-MS. Two animal models were used to evaluate the antithrombotic effect of ZXC, the arterial thrombosis model and a venous thrombosis model. ZXC prolonged the plasma recalcification time (PRT), the activated partial thromboplastin time (APTT), the thrombin time (TT) and the prothrombin time (PT) and clearly reduced the content of fibrinogen (FIB) obviously in the arterial thrombosis model. Furthermore, it markedly suppressed the level of TXB2 and up-regulated the level of 6-keto-PGF1a. In addition, it significantly up-regulated the level of t-PA and down-regulated the level of PAI-1 (p < 0.05). These results revealed that ZXC played a vital role in the prevention of thrombosis through interacting with multiple targets, including inhibition of coagulation and platelet aggregation and increasing thrombolysis. A total of 23 compounds were identified as the main components of ZXC by HPLC-DAD-ESI-IT TOF-MS.

Endothelial dysfunction correlates with decompression bubbles in rats.

Previous studies have documented that decompression led to endothelial dysfunction with controversial results. This study aimed to clarify the relationship between endothelial dysfunction, bubble formation and decompression rate. Rats were subjected to simulated air dives with one of four decompression rates: one slow and three rapid. Bubble formation was detected ultrasonically following decompression for two hours, before measurement of endothelial related indices. Bubbles were found in only rapid-decompressed rats and the amount correlated with decompression rate with significant variability. Serum levels of ET-1, 6-keto-PGF1α, ICAM-1, VCAM-1 and MDA, lung Wet/Dry weight ratio and histological score increased, serum NO decreased following rapid decompression. Endothelial-dependent vasodilatation to Ach was reduced in pulmonary artery rings among rapid-decompressed rats. Near all the above changes correlated significantly with bubble amounts. The results suggest that bubbles may be the causative agent of decompression-induced endothelial damage and bubble amount is of clinical significance in assessing decompression stress. Furthermore, serum levels of ET-1 and MDA may serve as sensitive biomarkers with the capacity to indicate endothelial dysfunction and decompression stress following dives.

Pharmacokinetics, Efficacy, and Safety of the Preservative-free Fixed Combination of Tafluprost 0.0015% and Timolol 0.5% in Healthy Volunteers: A Phase I Comparison vs. the Corresponding Preservative-free Monotherapies.

PURPOSE: Plasma concentrations of tafluprost acid and timolol were compared after single (Day 1) and repeated (Day 8) instillations of once-daily tafluprost 0.0015%-timolol 0.5% preservative-free (PF) fixed-dose combination (FDC), once-daily PF tafluprost 0.0015%, and twice-daily PF timolol 0.5%. PATIENTS AND METHODS: Fifteen healthy volunteers were randomized to this double-masked, single-center, three-period cross-over study. A wash-out interval of at least 4 weeks separated each three 8-day dosing period. Blood samples were drawn on the first and last day of each dosing period, prior to the morning dose, as well as 5, 10, 15, 30, and 45 min, and 1, 1.5, 2, 4, 8, and 12 h post-dosing. Sample plasma concentrations of tafluprost acid and/or timolol were determined and maximum concentration (C max), area under the concentration-over-time curve from time zero to the last time point with a quantifiable measurement (AUC0-last), and time to maximum concentration were calculated. Intraocular pressure (IOP), adverse events, and ocular/systemic safety variables were also evaluated. RESULTS: Plasma concentrations of tafluprost acid were low, with similar levels measured subsequent to either single or repeated dosing of PF FDC and PF tafluprost. On both sampling days, concentrations peaked at 10 min after the dose, and were cleared from the blood circulation by 30 min; average C max ranged from 17 to 24 pg/mL, and AUC0-last from 3 to 5 pg*h/mL. Plasma concentrations of timolol were comparable after the first dose of PF FDC or PF timolol. Concentrations peaked at 15 min post-dose and diminished in a similar manner after 2 h; average C max was 800 pg/mL and AUC0-last 3900 pg*h/mL. As expected, PF timolol produced a higher Day 8 pre-dose timolol concentration than PF FDC (235 vs. 37 pg/mL; p < 0.001, respectively). The Day 8 post-dose changes in timolol concentrations were relative to this pre-dose difference. All study treatments were well tolerated and safe. PF FDC seemed to provide the best IOP reduction. CONCLUSIONS: PF FDC demonstrated good IOP-lowering efficacy and displayed similar pharmacokinetic characteristics to the monotherapy agents. Exposure to timolol was reduced via the halved dosing.

Effect of volume replacement during combined experimental hemorrhagic shock and traumatic brain injury in prostanoids, brain pathology and pupil status.

Traumatic brain injury (TBI) is the main cause of trauma-related deaths. Systemic hypotension and intracranial hypertension causes cerebral ischemia by altering metabolism of prostanoids. We describe prostanoid, pupilar and pathological response during resuscitation with hypertonic saline solution (HSS) in TBI. Method Fifteen dogs were randomized in three groups according to resuscitation after TBI (control group; lactated Ringer's (LR) group and HSS group), with measurement of thromboxane, prostaglandin, macroscopic and microscopic pathological evaluation and pupil evaluation.Result Concentration of prostaglandin is greater in the cerebral venous blood than in plasma and the opposite happens with concentration of thromboxane. Pathology revealed edema in groups with the exception of group treated with HSS.Discussion and conclusion There is a balance between the concentrations of prostaglandin and thromboxane. HSS prevented the formation of cerebral edema macroscopically detectable. Pupillary reversal occurred earlier in HSS group than in LR group.

Effect of volume replacement during combined experimental hemorrhagic shock and traumatic brain injury in prostanoids, brain pathology and pupil status / Efeito da reposição volêmica durante o choque hemorrágico combinado com traumatismo craniencefálico sobre prostanóides, patologia cerebral e status pupilar

Traumatic brain injury (TBI) is the main cause of trauma-related deaths. Systemic hypotension and intracranial hypertension causes cerebral ischemia by altering metabolism of prostanoids. We describe prostanoid, pupilar and pathological response during resuscitation with hypertonic saline solution (HSS) in TBI. Method Fifteen dogs were randomized in three groups according to resuscitation after TBI (control group; lactated Ringer’s (LR) group and HSS group), with measurement of thromboxane, prostaglandin, macroscopic and microscopic pathological evaluation and pupil evaluation.Result Concentration of prostaglandin is greater in the cerebral venous blood than in plasma and the opposite happens with concentration of thromboxane. Pathology revealed edema in groups with the exception of group treated with HSS.Discussion and conclusion There is a balance between the concentrations of prostaglandin and thromboxane. HSS prevented the formation of cerebral edema macroscopically detectable. Pupillary reversal occurred earlier in HSS group than in LR group.

O traumatismo cranioencefálico (TCE) é a principal causa de morte relacionada ao trauma. O choque hemorrágico e hipertensão intracraniana causam isquemia cerebral alterando o metabolismo de prostanóides. Neste estudo, relatamos o comportamento dos prostanóides, resposta pupilar e patologia durante a reposição volêmica com solução salina hipertônica (SSH) no TCE. Método Quinze cachorros foram randomizados em três grupos (controle, grupo de Ringer lactato e grupo de SSH) e foram avaliados tromboxane, prostaglandina, avaliação patológica macroscópica e microscópica e status pupilar.Resultado A concentração de prostaglandina é maior no sangue cerebral em comparação ao plasma, e o inverso ocorre com o tromboxane. A patologia revelou edema em todos os grupos, com exceção do grupo tratado com SSH.Discussão e conclusão Existe um equilíbrio entre concentrações cerebrais e plasmáticas de prostaglandina e tromboxane. A SSH protegeu o cérebro da formação de edema pós traumático.

Virgin olive oil, palm olein and coconut oil diets do not raise cell adhesion molecules and thrombogenicity indices in healthy Malaysian adults.

BACKGROUND/OBJECTIVES: Effects of high-protein diets that are rich in saturated fats on cell adhesion molecules, thrombogenicity and other nonlipid markers of atherosclerosis in humans have not been firmly established. We aim to investigate the effects of high-protein Malaysian diets prepared separately with virgin olive oil (OO), palm olein (PO) and coconut oil (CO) on cell adhesion molecules, lipid inflammatory mediators and thromobogenicity indices in healthy adults. METHODS: A randomized cross-over intervention with three dietary sequences, using virgin OO, PO and CO as test fats, was carried out for 5 weeks on each group consisting of 45 men and women. These test fats were incorporated separately at two-thirds of 30% fat calories into high-protein Malaysian diets. RESULTS: For fasting and nonfasting blood samples, no significant differences were observed on the effects of the three test-fat diets on thrombaxane B2 (TXB2), TXB2/PGF1α ratios and soluble intracellular and vascular cell adhesion molecules. The OO diet induced significantly lower (P<0.05) plasma leukotriene B4 (LTB4) compared with the other two test diets, whereas PGF1α concentrations were significantly higher (P<0.05) at the end of the PO diet compared with the OO diet. CONCLUSION: Diets rich in saturated fatty acids from either PO or CO and high in monounsaturated oleic acid from virgin OO do not alter the thrombogenicity indices-cellular adhesion molecules, thromboxane B2 (TXB2) and TXB2/prostacyclin (PGF1α) ratios. However, the OO diet lowered plasma proinflammatory LTB4, whereas the PO diet raised the antiaggregatory plasma PGF1α in healthy Malaysian adults. This trial was registered at clinicaltrials.gov as NCT 00941837.

The effect of parenteral lipid emulsions on pulmonary hemodynamics and eicosanoid metabolites in preterm infants: a pilot study.

BACKGROUND: Soy-based intravenous fat emulsion (IVFE) is known to cause a rise in pulmonary artery pressure in the preterm infant, thought to be mediated through eicosanoid metabolites of linoleic acid. We compared the effect of soy-based IVFE and an olive-oil-based IVFE containing less than half the content of linoleic acid on pulmonary artery pressure and eicosanoid metabolites in preterm infants receiving parenteral nutrition. METHODS: In this pilot study at a regional neonatal intensive care unit (ICU), infants received either a soy-based or olive-oil-based IVFE as part of an otherwise identical feeding protocol. Pulmonary artery pressure and urinary thromboxane B2 and prostaglandin F1 alpha were measured at baseline and maximum lipid infusion. RESULTS: There was a greater fall in pulmonary artery pressure in the olive-oil-based IVFE group compared with the soy-based IVFE group. A decrease in urine thromboxane/prostaglandin F1 alpha ratio was seen only in the olive-oil-based IVFE group. CONCLUSIONS: In the parenterally fed preterm infant, an olive-oil-based IVFE may have a beneficial effect on pulmonary artery pressure when compared with soy-based IVFE. Effects on pulmonary vascular tone are likely to be mediated through alterations in eicosanoid metabolism. A randomized trial is warranted to compare the effects of different lipid emulsions.

Influence of ShuJinHuoXue tablets on ischemia reperfusion injury of animals' skeletal muscle.

Ischemia-reperfusion (IR) can lead to serious tissue oxidative injury in animals. ShuJinHuoXue tablet (SJHXT) is a Chinese Traditional Medicine which can relax the muscles and stimulate the blood circulation and has been used as a clinical medicine. In the present study, we investigated the effects of SJHXT pretreatment on oxidative injury using an animal model of acute limb IR. Results showed that SJHXT pre-treatment (200, 300 and 400 mg/kg/day) markedly reduced serum endothelin-1 (ET-1), thromboxane B2 (TXB2) levels and thromboxane B2/6-keto- prostaglandin F1α (TXB2/6-Keto-PGF(1α)), wet weight/dried weight (W/D) ratio, myeloperoxidase (MPO), creatine kinase (CK), lactate dehydrogenase (LDH) activities, and increased serum nitric oxide (NO), 6-Keto-PGF(1α) levels and NO/ET-1 ratio in the IR+SJHXT groups. In addition, the SJHXT pre-treatment (200, 300 and 400 mg/kg/day) markedly reduced skeletal muscle Ca²âº, malondialdehyde (MDA) levels, increased Na⁺-K⁺-ATPase, Ca²âº-Mg²âº-ATPase, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities. Our results suggest that SJHXT pre-treatment may improve skeletal muscle blood vessel microcirculation, decrease skeletal muscle oxidative injury and enhance antioxidant enzymes activities in IR animals.

Effect of nisoldipine and olmesartan on endothelium-dependent vasodilation in essential hypertensive patients.

AIMS: To investigate whether nisoldipine and olmesartan improve endothelial function, decrease asymmetric dimethylarginine (ADMA) and alleviate the inflammatory and oxidative process. METHODS: Fifty-five essential hypertensive patients were randomized to receive nisoldipine or olmesartan for 8 weeks according to a parallel-group, active-controlled, single blind study, and 28 matched normotensive subjects served as healthy controls. Flow-mediated dilation (FMD), and plasma levels of nitric oxide (NO), endothelin-1 (ET-1), high-sensitive C-reactive protein (hs-CRP), 8-isoprostane (also named 8-isoPGF2α), and ADMA were determined. RESULTS: At baseline, the plasma levels of ADMA, ET-1, hs-CRP, and 8-isoPGF2α were markedly higher in patients with essential hypertension than in normotensive subjects (P < 0.05). A significant positive correlation was observed between plasma levels of ET-1 and ADMA in patients with essential hypertension, but not in normotensive subjects. The NO plasma concentrations were significantly lower in patients with essential hypertension than in normotensive subjects. Furthermore, hypertensive subjects demonstrated significantly lower FMD than healthy control (P < 0.05). Nisoldipine and olmesartan significantly and similarly reduced blood pressure in patients with essential hypertension (P < 0.001). At the end of the 8-week treatment, plasma ADMA and ET-1 levels were decreased significantly (P < 0.01). FMD increased significantly in nisoldipine or olmesartan-treated patients (P < 0.05). A significant decrease in plasma hs-CRP contents was observed in patients receiving nisoldipine (P < 0.05). CONCLUSION: The findings demonstrate that nisoldipine and olmesartan both improve FMD in patients with essential hypertension. This may be associated with decreased circulating levels of CRP, ET-1, and ADMA.

The role of inflammation and COX-derived prostanoids in the effects of bradykinin on isolated rat aorta and urinary bladder.

Bradykinin, a vasoactive peptide, increases during inflammation and induces the formation of prostaglandins through specific receptor activation. Two types of receptors mediate the biological effects of bradykinin, B(1) and B(2) receptors. Although B(2) receptors are present in most tissues, B(1) receptors are expressed after inflammatory stimuli or tissue injury. Bradykinin has a high affinity for B(2) and a low affinity for B(1) receptors, whereas the opposite occurs for des-Arg(9)-bradykinin. Recently, it has been reported that nonsteroidal anti-inflammatory drugs have different inhibitory activities on cyclooxygenase isozymes, COX-1, COX-2, and COX-3. In the present study, we have investigated the contributions of different COX isozyme inhibitions and inflammation on bradykinin-induced effects of isolated rat aorta and urinary bladder smooth muscle contractions. Male Sprague-Dawley rats weighing 200-250 g were used in the study. The vasodilatory responses to bradykinin (1 nM-1 µM) were studied on isolated rat aorta rings contracted with norepinephrine (0.1 µM) following incubation with dipyrone (100, 700, and 2,000 µM). The relaxant responses of dipyrone (100, 700, and 2,000 µM) were also compared on the isolated rat urinary bladder contracted with bradykinin (n = 8). A bacterial lipopolysaccharide was used for the induction of inflammation (n = 8). The levels of PGE(2), PGF(1α), TXB(2), nitric oxide synthase (NOS), IL-10, and TNF-α were all determined in both the plasma and the perfusate of the aorta preparations (n = 5). The vasodilatory activities of bradykinin and des-Arg9-bradykinin were significantly increased upon the inhibition of COX-3 (dipyrone at 100 µM). These effects disappeared in the inflamed group. PGE(2), PGF1α, and TXB(2) were significantly high, but NOS activity was low in the aorta perfusate after the inhibition of COX-3. Dipyrone showed the relaxant activity of the urinary bladder contracted with bradykinin. The vasodilatory activity of des-Arg(9)-bradykinin was in the inflamed group but not in the non-inflamed group. Bradykinin did not contract urinary bladder in inflamed group. The results suggest that COX-induced products may play an important role in the bradykinin-induced rat aortic smooth muscle relaxations.

Selective cyclooxygenase inhibition improves hepatic encephalopathy in fulminant hepatic failure of rat.

Prostaglandin plays an important role in the pathogenesis of hepatic encephalopathy. This study investigated the therapeutic effects of selective cyclooxygenase (COX) inhibitor on hepatic encephalopathy in thioacetamide-induced fulminant hepatic failure (FHF) rats. The selective COX-1 inhibitor (SC-560), COX-2 inhibitor (NS-398) or distilled water (control) was administered in the normal and FHF rats. The mortality rates were calculated and severity of hepatic encephalopathy was evaluated using Opto-Varimex activity sensors. Besides, the levels of blood ammonia, 6-keto-prostaglandin-F(1α) (PGF(1α), active metabolite of prostacyclin), tumor necrosis factor α (TNF-α) and liver biochemistry tests were measured. The hepatic mRNA expressions of nitric oxide synthase and COX were determined, and the liver histopathological changes were examined. The liver biochemistries and motor activities were similar among COX-1, COX-2 treated and control groups. SC-560 treatment improved the survival of FHF rats (mortality rates: SC-560 group 0%, control 33%; P=0.037). Besides, SC-560 treatment improved hepatic encephalopathy and decrease plasma levels of PGF(1α), but did not change TNF-α levels. There were no significant differences in liver biochemistry and ammonia levels except that the aspartate aminotransferase levels were lower in the NS-398 treated group. Both hepatic COX-1 and COX-2 mRNA expressions were attenuated after SC-560 treatment. The decreased COX-2 and increased constitutive nitric oxide synthase mRNA expressions were found after NS-398 treatment. Besides, the histopathology of liver got improved after selective COX inhibition. In conclusion, COX-1 inhibition by SC-560 decreases the mortalities and improves motor activities, suggesting COX-1, rather than COX-2, plays a major role in hepatic encephalopathy of FHF rats.

Metabolism and ocular tissue distribution of an antiglaucoma prostanoid, tafluprost, after ocular instillation to monkeys.

PURPOSE: To investigate the metabolism of a new antiglaucoma difluoroprostaglandin, tafluprost, in ocular tissues and evaluate the distribution of the parent drug and its metabolites in ocular and systemic tissues after a single ocular administration to cynomolgus monkeys (Macaca fascicularis). METHODS: A single dose of an ophthalmic solution containing 0.0005%, 0.005%, or 0.05% [(3)H]tafluprost was topically instilled (20 µL/eye) to male and/or female cynomolgus monkeys to study tissue distribution and metabolism. Blood, ocular/systemic tissues, or excreta were collected until 24 h after dosing. The radioactivity of each sample was measured by liquid scintillation counting, and metabolites were characterized by liquid chromatography-mass spectrometry. The major metabolites found in ocular tissues were intracameraly administered to monkeys to confirm their effect on intraocular pressure (IOP). RESULTS: Soon after dosing, high concentrations of drug-related radioactivity were observed in the cornea and bulbar/palpebral conjunctiva, followed by the iris, sclera, choroid with retinal pigmented epithelium, and aqueous humor. The highest concentration of radioactivity concentrations occurred in the anterior and posterior ocular tissues within 2 h after dosing. The radioactivity measured in the plasma and ocular tissues was proportional to the dose administered. The major metabolites of tafluprost identified in the ocular tissues were tafluprost acid and 1,2-dinor- and 1,2,3,4-tetaranor-tafluprost acid. The estimated concentration of tafluprost acid in the aqueous humor and ciliary body was enough to stimulate prostanoid FP-receptors. After hydrolysis to the acid form, the primary metabolic pathway of tafluprost was via ß-oxidation and, subsequently, oxidation. No metabolic reactions to the 15-carbon position were observed. Tafluprost acid was shown to significantly lower the IOP, whereas 1,2-dinor- and 1,2,3,4-tetaranor-tafluprost acid did not. CONCLUSIONS: Topically administered [(3)H]tafluprost was well absorbed into the ocular and systemic tissues of the primary nonclinical species, monkey. The amount of the pharmacologically active form, that is, tafluprost acid, was high enough to occupy the target FP receptors at the site of action. The pharmacokinetic and metabolic properties of this difluorinated prostaglandin in primates are believed to result in clinical benefits of a long-term IOP-lowering effect.

Aspirin inhibits fractalkine expression in atherosclerotic plaques and reduces atherosclerosis in ApoE gene knockout mice.

OBJECTIVE: To determine the fractalkine expression in the aorta of ApoE (-/-) mice and the effect of high-dose aspirin intervention on fractalkine expression and atherosclerotic lesion formation. METHODS: Twenty-one male ApoE gene knockout mice were randomized into three groups to receive either placebo in addition to normal mice chow (n = 7), placebo in addition to a high-fat diet (n = 7), or aspirin (58 mg/kg/d) in addition to a high-fat diet (n = 7). After 12 weeks of study, the mice were euthanized and serum cholesterol, thromboxane B(2), and 6-keto-PGF(1alpha) were examined. Fractalkine and cyclooxygenase expression in aorta were measured and the atherosclerotic lesion analyzed. RESULTS: Pathology image analysis showed that the atherosclerotic plaque was the most extensive in the high-fat diet group while the addition of aspirin greatly reduced the severity of the plaque. Both RT-PCR analysis and immunohistochemical analysis showed that fractalkine expression was the strongest in the high-fat diet group and was significantly decreased by aspirin treatment. Serum thromboxane B(2) was lowered by aspirin while 6-keto-PGF(1alpha) and cholesterol remained unchanged. CONCLUSIONS: The results of our study indicate that high dose aspirin can improve the atherosclerotic lesion and suppress the fractalkine expression in murine aorta.

Disposition and metabolism of a novel prostanoid antiglaucoma medication, tafluprost, following ocular administration to rats.

The disposition and metabolism of tafluprost, an ester prodrug of the 15,15-difluoro-prostaglandin F(2alpha) antiglaucoma agent, have been studied in rats after ocular administration. Radioactivity was absorbed very rapidly into the eye and systemic circulation after a single ocular dose of 0.005% [(3)H]tafluprost ophthalmic solution, with maximum levels in plasma and most eye tissues occurring within 15 min. The absorption ratio of radioactivity was approximately 75%, suggesting the high availability of ocular administration of tafluprost. Approximately 10% of the dose was present in cornea at this time, and radioactivity concentrations in this tissue exceeded those in aqueous humor and iris/ciliary body throughout the 24-h study period. After repeated daily ocular doses, radioactivity levels remained greatest in cornea, followed by iris/ciliary body that replaced aqueous humor as the eye tissue containing the second highest radioactivity concentration. In female rats, radioactivity was excreted equally between urine and feces after a single ocular dose, whereas in male rats more was excreted in feces, reflecting the greater biliary excretion in males rats (50% dose) compared with females rats (33% dose). Tafluprost was extensively metabolized in the rat, such that intact prodrug was not detected in plasma, tissues, or excreta by radio-high-performance liquid chromatography. On the other hand, the active moiety, tafluprost acid, was the only noteworthy radioactive component in cornea, aqueous humor, and iris/ciliary body for at least 8 h after the ocular dose, and it was also a major plasma metabolite in early time points. The gender differences in conjugation reactions resulted in the differences in the excretion.

Lipoproteins inhibit platelet aggregation and arachidonic acid metabolism in experimental hypercholesterolaemia.

1. Human plasma contains unidentified components that inhibit arachidonic acid (AA) metabolism. In the present study, we investigated whether plasma from rabbits fed a normal or high-cholesterol diet for 16 weeks also inhibits AA metabolism. Specifically, we studied the effects of plasma on platelet aggregation and on the production of AA metabolites, tri-hydroxyeicosatrienoic acid, 12-hydroxyeicosatetraenoic acid and thromboxane B(2). 2. Haematological and lipid profiles were altered by a high-cholesterol diet. Platelets from hypercholesterolaemic rabbits showed enhanced aggregatory sensitivity to AA and platelet-activating factor. However, plasma from hypercholesterolaemic and control rabbits, when added to the incubation mixture, significantly inhibited platelet aggregation and eicosanoid production. 3. High- and low-density lipoprotein (HDL and LDL, respectively) concentrations increased several-fold in plasma with cholesterol feeding. When added directly to the incubation mixture, both HDL and LDL inhibited platelet aggregation, as well as AA metabolism. 4. Haptoglobin, albumin and Cohn's fraction IV, but not globulins, exhibited antiplatelet and anti-AA metabolism activities. Their concentrations in plasma were not affected by cholesterol feeding. 5. We conclude that LDL and HDL account for at least some of the inhibition of AA metabolism produced by plasma.

Time course and attenuation of ischaemia-reperfusion induced oxidative injury by propofol in human renal transplantation.

Ischaemia-reperfusion injury resulting from interruption and restoration of blood flow might be related to free radical mediated oxidative stress and inflammation, and subsequently to post-surgery related complications. We studied the impact of renal transplantation on oxidative stress and inflammation by measuring F(2)-isoprostanes and prostaglandin F(2alpha), respectively, during transplantation and post-surgery. Additionally, due to earlier observations, two dissimilar anaesthetic agents (thiopentone and propofol) were compared to determine their antioxidative capacity rather than their anaesthetic properties. Blood samples were collected before, post-intubation, immediately, 30, 60,120, 240 min, and 12 and 24 h after reperfusion. Oxidative stress and inflammatory response were detected by measuring 8-iso-PGF(2alpha) (a major F(2)-isoprostane and a biomarker of oxidative stress) and 15-keto-dihydro-PGF(2alpha) (a major metabolite of PGF(2alpha) and a biomarker of COX-mediated inflammatory response), respectively. Reperfusion of the transplanted graft significantly increased plasma levels of 8-iso-PGF(2alpha). PGF(2alpha) metabolite levels, although elevated, did not reach statistical significance. In addition, significantly lower levels of 8-iso-PGF(2a) were observed in the propofol group compared to the thiopentone group. Together, these findings underline an augmented oxidative stress activity following an inflammatory response after human renal transplantation. Furthermore, propofol a well-known anaesthetic, counteracted oxidative stress by lowering the formation of a major F(2)-isoprostane.

Plasma levels of nitrites, PGF1alpha, and nitrotyrosine in LPS-treated rats: functional and histochemical implications in aorta.

We investigated the effects of lipopolysaccharide (LPS) administration on plasma nitrite, nitrotyrosine and 6-keto prostaglandin F1alpha, (PGF1alpha) levels and the related resultant changes in function and histochemistry of aorta in rats. Plasma nitrite and PGF1alpha nitrotyrosine levels were analysed after 5 mg/kg intravenous LPS was administered to rats compared with those in non-treated rats. The distribution of nitrotyrosine in the aorta was studied immunohistochemically. The contractile responses of aortic rings to phenylephrine (PE) from both the LPS-treated and control rats were studied in the organ baths. There were increases in plasma nitrite, PGF1alpha, and nitrotyrosine concentrations of LPS-treated rats compared to non-treated rats. Immunoreactivity of nitrotyrosine residues were detected in the endothelial and smooth muscle cells in LPS-treated but not in control rat aorta. The contractile responses to PE of the LPS-treated rat aortic rings were significantly reduced as compared with those of control rat's. Incubation of the aortic rings from LPS-treated rats with cyclooxygenase inhibitor indomethacine or with a combination of indomethacine and nitric oxide synthase inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME) increased the contractile responses to the levels observed in control rats suggesting that both prostanoids and particularly nitric oxide (NO) are involved in the reduced contractile responses in LPS-treated rats. These results supported the view that LPS might cause an increment in both NO and PGI2 levels. This increase in the NO and PGI2 levels may be responsible from the reduction in responses of aorta to contractile agents in LPS-treated rats. Increased peroxynitrite formation in LPS-treated rats may lead to nitration of the tyrosil residues of the proteins in the aorta.

Conception rate and reproductive function of dairy cows fed different fat sources.

The objective of the experiment was to determine the effects of fat supplementation on cyclicity, progesterone concentration, follicular development, conception rate, embryo mortality, and plasma concentrations of prostalglandin F metabolite (PGFM) in cattle. The hypothesis of this experiment was that feeding flaxseed, which is a source rich in C18:3, would increase conception rate of dairy cows due to decreased plasma PGFM concentrations. A total of 138 lactating Holstein cows were allotted at calving to three groups of 46 cows, blocked for similar calving dates. Cows within each block were assigned to one of three isonitrogenous, isoenergetic, and isolipidic supplements based on either whole flaxseed (FLA), Megalac (MEG) or micronized soybeans (SOY). The diets were fed from calving to Day 50 of pregnancy for pregnant cows, or 120 day postpartum for those not diagnosed pregnant after AI. Detailed measurements of PGFM and follicle dynamics were only made on four cows for FLA and five cows for both MEG and SOY. The response in PGFM concentration following the oxytocin challenge administered around Week 11 of lactation was similar over time among treatments. Plasma progesterone concentrations from Days 17 to 21 of the estrous cycle starting around Week 9 of lactation and determined on a subsample of cows (n=for FLA and n=5 for both MEG and SOY) were higher for cows fed FLA than for those fed SOY (P=0.04) or MEG (P=0.06). Conception rates were similar among treatments. Total embryo mortality was lower (P=0.07) for cows fed FLA (0%) compared to those fed either MEG (15.4%) or SOY (8.0%). The mean size of the CL measured during a complete estrous cycle from Week 9 of lactation was smaller for cows fed SOY (16.3 mm) compared to those fed either FLA (19.1 mm) or MEG (18.3 mm). We inferred that pregnancy losses could be reduced by feeding whole flaxseed as a result of its effects on different factors such as modulation in concentration of progesterone and size of the CL.

Relation of C-reactive protein to oxidative stress and to endothelial activation in essential hypertension.

BACKGROUND: C-reactive protein (CRP) predicts cardiovascular outcome. Oxidative stress is considered to be involved in endothelial alteration. We hypothesized that in essential hypertension (EH), oxidative stress, as measured by 8-iso-prostaglandin-F(2alpha) (8-iso-PGF(2alpha)), should be associated with increased CRP and endothelial activation, as evaluated by soluble intercellular adhesion molecule-1 (ICAM-1) and vascular adhesion molecule-1 (VCAM-1) plasma levels. METHODS: In 83 subjects with mild EH and in 50 healthy control subjects we measured, in basal conditions, plasma levels of hs-CRP, 8-iso-PGF(2alpha), ICAM-1 and VCAM-1, and tumor necrosis factor-alpha (TNF-alpha). RESULTS: Subjects with EH had higher levels of 8-iso-PGF(2alpha) (P < .0001), CRP (P < .001), ICAM-1 and VCAM-1 (P < .001), and TNF-alpha (P < .001) than did control subjects. We divided successively EH according to CRP values (<1, 1-3, >3 mg/L), and we observed increasing and significantly different levels of the endothelial parameters and of TNF-alpha along with increasing CRP. Linear analysis of correlation pointed out significant correlation of CRP with 8-iso-PGF(2alpha) (r = 0.730, P < .001), ICAM-1 and VCAM-1 (r = 0.642 and 0.468, P < .001 respectively), and TNF-alpha (r = 0.609, P < .001). Multiple regression analysis using CRP as a dependent variable confirmed the relationship of CRP with systolic blood pressure (beta 0.216, P = 0.039) and with 8-iso-PGF(2alpha) (beta 0.602, P = .0001). CONCLUSIONS: Our data demonstrate that in EH, inflammatory molecules such as CRP and TNF-alpha are increased and related to both oxidative stress and endothelial activation.

Effects of nitric oxide and prostacyclin on hemodynamic response by big endothelin-1 in near term fetal sheep.

AIMS: To measure plasma concentrations of endothelin (ET)-1, NO metabolites (nitrate/nitrite; NOx) and 6-keto PGF1 alpha (PGF1 alpha) in maternal and fetal sheep blood, and to evaluate the effects of big ET-1 on hemodynamic response, blood gases and NO and 6-keto PGF1 alpha production in near term fetal sheep. METHODS: Hemodynamic parameters were measured during infusion of big ET-1 into the carotid vein in chronically catheterized fetal sheep on day 125 of gestation. Fetal arterial blood samples were obtained for ET-1, PGF1 alpha) and nitrate/nitrite (NOx) measurements. RESULTS: ET-1, NOx and PGF1 alpha plasma concentrations were all significantly higher in fetal compared with the maternal plasma. Big ET-1 significantly decreased fetal systolic and diastolic blood pressure and significantly increased fetal heart rate. Big ET-1 stimulated plasma PGF1 alpha), but not NOx , concentration. CONCLUSIONS: Circulatory regulating factors in the fetus were up-regulated. The effects of ET-1 on fetal hemodynamic response may be mediated via prostacyclin, but not via the NO pathway.