Influence of exogenous phytase supplementation on phytate degradation, plasma inositol, alkaline phosphatase, and glucose concentrations of broilers at 28 days of age.

Inositol is the final product of phytate degradation, which has the potential to serve as an indicator of phytase efficacy. An experiment was conducted to evaluate effects of supplementing broiler diets with phytase on phytate degradation and plasma inositol concentrations at 28 d of age. Twenty-four Ross × Ross 708 male chicks were placed in battery cages (4 birds per cage) from 1 to 21 d of age and individually from 22 to 28 d of age. At 27 d of age, a catheter was placed in the brachial vein of broilers to avoid repeated puncture of the vein during blood collection. At 28 d of age, broilers received 1 of 3 experimental diets formulated to contain 0, 400, or 1,200 phytase units (FTU)/kg, respectively, in diet 1, 2, and 3. Blood was collected 1 h before feeding experimental diets and from 20 to 240 min after feeding experimental diets at 20-min intervals with a final blood collection at 480 min to determine plasma inositol concentrations. Inositol phosphate (IP) ester degradation was determined in gizzard contents and ileal digesta. Broilers provided the 1,200 FTU/kg phytase diet had 60% less (P < 0.01) IP6 concentration in gizzard content (1,264 vs. 4,176 nmol/g) and ileal digesta (13,472 vs. 33,244 nmol/g) than birds fed the 400 FTU/kg diet. Adding phytase at 1,200 FTU/kg increased (P < 0.01) inositol concentrations in gizzard content and ileal digesta of broilers by 2.5 (2,703 vs. 1,071 nmol/g) and 3.5 (16,485 vs. 4,667 nmol/g) fold, respectively, compared with adding 400 FTU/kg. Plasma inositol concentration of broilers was not different (P = 0.94) among the dietary treatments at each collection time. Inositol liberation in the digesta of broilers fed diets with 1,200 FTU/kg phytase did not translate to increased plasma inositol concentrations, which warrants further investigation.

Effects of supplementation of DL-methionine on tissue and plasma antioxidant status during heat-induced oxidative stress in broilers.

Exposure to high ambient temperature has been shown to impair growth performance and to cause oxidative stress in broilers. This study investigated the hypothesis that supplementation with methionine (Met) as DL-Met (DLM) more than the National Research Council recommendations improves growth performance and alleviates oxidative stress in broilers exposed to high ambient temperature. One-day-old male Cobb-500 broilers (n = 68) were allotted to 4 groups and phase-fed 3 basal diets during days 1 to 10, 11 to 21, and 22 to 35. One group was kept under thermoneutral temperature conditions and received the basal diets with Met + cysteine (Cys) concentrations according to recommendations of NRC. The other 3 groups were kept in a room with an increased ambient temperature from week 3 to 5 and were fed either the basal diet or the basal diets supplemented with 2 levels of DLM in which Met + Cys concentrations exceeded NRC recommendations by around 20% (group DLM1) and 40% (group DLM2), respectively. As expected, the broilers exposed to high ambient temperature showed a lower feed intake, lower body weight gains, a higher feed:gain ratio, and biochemical indications of oxidative stress in comparison to broilers kept under thermoneutral temperature conditions. Supplementation of DLM did not improve the growth performance in broilers exposed to high ambient temperature. However, the broilers supplemented with DLM had increased concentrations of glutathione in liver and breast muscle (groups DLM1 and DLM2), increased concentrations of tocopherols in the liver (group DLM2), and reduced concentrations of 7α-hydroxycholesterol and 7-ketocholesterol in heat-processed thigh muscle (groups DLM1 and DLM2) in comparison to the control group exposed to high ambient temperature. Concentrations of thiobarbituric acid-reactive substances and vitamin C in plasma, liver, and muscle were not different between the 3 groups exposed to heat stress. Nevertheless, the study shows that supplementation of DLM in slight excess of the Met concentration required for maximum growth performance improved the antioxidant status in tissues and reduced the susceptibility of muscle toward oxidation in heat-stressed broilers.

N-Acetylcysteine supplementation alleviates intestinal injury in piglets infected by porcine epidemic diarrhea virus.

Porcine epidemic diarrhea virus (PEDV) infects the intestine of young pigs, but effective measures for prevention and treatment are lacking. N-Acetylcysteine (NAC) has been shown to reduce endotoxin-induced intestinal dysfunction. This study was conducted with the PEDV-infected neonatal piglet model to determine the effect of NAC supplementation on intestinal function. Thirty-two 7-day-old piglets were randomly allocated to one of four treatments in a 2 × 2 factorial design consisting of two liquid diets (0 or 50 mg/kg BW NAC supplementation) and oral administration of 0 or 104.5 TCID50 (50% tissue culture infectious dose) PEDV. On day 7 of the trial, half of the pigs (n = 8) in each dietary treatment received either sterile saline or PEDV (Yunnan province strain) solution at 104.5 TCID50 per pig. On day 10 of the trial, D-xylose (0.1 g/kg BW) was orally administrated to all pigs. One hour later, jugular vein blood samples were collected, and then all pigs were killed to obtain the small intestine. PEDV infection increased diarrhea incidence, while reducing ADG. PEDV infection also decreased plasma D-xylose concentration, small intestinal villus height, mucosal I-FABP and villin mRNA levels but increased mucosal MX1 and GCNT3 mRNA levels (P < 0.05). Dietary NAC supplementation ameliorated the PEDV-induced abnormal changes in all the measured variables. Moreover, NAC reduced oxidative stress, as indicated by decreases in plasma and mucosal H2O2 levels. Collectively, these novel results indicate that dietary supplementation with NAC alleviates intestinal mucosal damage and improves the absorptive function of the small intestine in PEDV-infected piglets.

Pronounced between-subject and circadian variability in thymidylate synthase and dihydropyrimidine dehydrogenase enzyme activity in human volunteers.

AIMS: The enzymatic activity of dihydropyrimidine dehydrogenase (DPD) and thymidylate synthase (TS) are important for the tolerability and efficacy of the fluoropyrimidine drugs. In the present study, we explored between-subject variability (BSV) and circadian rhythmicity in DPD and TS activity in human volunteers. METHODS: The BSVs in DPD activity (n = 20) in peripheral blood mononuclear cells (PBMCs) and in plasma, measured by means of the dihydrouracil (DHU) and uracil (U) plasma levels and DHU : U ratio (n = 40), and TS activity in PBMCs (n = 19), were examined. Samples were collected every 4 h throughout 1 day for assessment of circadian rhythmicity in DPD and TS activity in PBMCs (n = 12) and DHU : U plasma ratios (n = 23). In addition, the effects of genetic polymorphisms and gene expression on DPD and TS activity were explored. RESULTS: Population mean (± standard deviation) DPD activity in PBMCs and DHU : U plasma ratio were 9.2 (±2.1) nmol mg(-1) h(-1) and 10.6 (±2.4), respectively. Individual TS activity in PBMCs ranged from 0.024 nmol mg(-1) h(-1) to 0.596 nmol mg(-1) h(-1) . Circadian rhythmicity was demonstrated for all phenotype markers. Between 00:30 h and 02:00 h, DPD activity in PBMCs peaked, while the DHU : U plasma ratio and TS activity in PBMCs showed trough activity. Peak-to-trough ratios for DPD and TS activity in PBMCs were 1.69 and 1.62, respectively. For the DHU : U plasma ratio, the peak-to-trough ratio was 1.43. CONCLUSIONS: BSV and circadian variability in DPD and TS activity were demonstrated. Circadian rhythmicity in DPD might be tissue dependent. The results suggested an influence of circadian rhythms on phenotype-guided fluoropyrimidine dosing and supported implications for chronotherapy with high-dose fluoropyrimidine administration during the night.

Dietary arginine and N-carbamylglutamate supplementation enhances the antioxidant statuses of the liver and plasma against oxidative stress in rats.

N-Carbamylglutamate (NCG), an effective precursor of arginine (ARG), can enhance ARG synthesis, increase intestinal growth, and improve reproductive performance. However, the antioxidant effect of NCG remains largely unknown. This study aims to survey the effects of ARG and NCG supplementation on the antioxidant statuses of the liver and plasma in rats under oxidative stress. Rats were fed for 30 days with one of the three iso-nitrogenous diets: basal diet (BD), BD plus 1% ARG, and BD plus 0.1% NCG. On day 28, half of the rats fed with BD were intraperitoneally injected with 12 mg per kg body weight of diquat (diquat group) and the other half was injected intraperitoneally with sterile 0.9% NaCl solution (control group). The other diet groups also received an intraperitoneal injection of 12 mg per kg body weight of diquat, as follows: diquat + 1% ARG (DT + ARG), and diquat + 0.1% NCG (DT + NCG). Rat liver and plasma samples obtained 48 h after diquat injection were analyzed. Results indicated that diquat significantly affected the plasma conventional biochemical components (relative to the controls), which were partially alleviated in both the DT + ARG and DT + NCG groups (P < 0.05). Diquat also significantly decreased the glutathione (GSH) content (by 30.0%), and decreased anti-superoxide anion (ASA; by 13.8%) and anti-hydroxyl radical (AHR; by 38.9%) abilities in the plasma, and also decreased catalase (CAT) activity both in the liver (by 17.5%) and plasma (by 33.4%) compared with the control group. By contrast, diquat increased the malondialdehyde (MDA) content (by 23.0%) in the plasma (P < 0.05) compared with the control group. Relative to those of the diquat group, higher CAT activity and GSH content were noted in the plasma of the DT + ARG group and in the liver of both DT + ARG and DT + NCG groups (P < 0.05). Furthermore, the DT + ARG group exhibited significantly enhanced plasma ASA activity (P < 0.05). The DT + NCG group showed significantly improved total antioxidant capacity (T-AOC) in the liver and plasma (P < 0.05). Increased GSH content and elevated ASA and AHR activities were also found, but the MDA content in the plasma was depleted (P < 0.05). Compared with the DT + ARG group, the DT + NCG group showed increased liver and plasma T-AOC, enhanced plasma AHR activity, increased liver ASA activity, and decreased plasma MDA content (P < 0.05). Overall, supplementation of 1% ARG and 0.1% NCG can partially protect the liver and plasma from oxidative stress. Furthermore, compared with 1% ARG, 0.1% NCG more effectively alleviated oxidative stress.

A deficiency or an excess of dietary threonine level affects weight gain, enzyme activity, immune response and immune-related gene expression in juvenile blunt snout bream (Megalobrama amblycephala).

A feeding trial was conducted to investigate the impacts of deficient and excess dietary threonine levels on weight gain, plasma enzymes activities, immune responses and expressions of immune-related genes in the intestine of juvenile blunt snout bream. Triplicate groups of fish (initial weight 3.01 ± 0.01 g, 30 fish per tank) were fed with deficient (0.58%), optimum (1.58%) and excess (2.58%) threonine level diets to near satiation four times a day for 9 weeks. A mixture of l-amino acids was supplemented to simulate the whole body amino acid pattern of blunt snout bream, except for threonine. The results showed that both deficiency and excess threonine level diets significantly (P < 0.05) reduced the weight gain of blunt snout bream. Excess dietary threonine level triggered plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities (P < 0.05); whereas superoxide dismutase (SOD) activity was not significantly influenced by imbalanced-dietary threonine level (P > 0.05). Plasma complement component 3 (C3) and component 4 (C4) concentrations were significantly depressed by the deficiency of dietary threonine (P < 0.05). Dietary threonine regulated the target of rapamycin (TOR), eukaryotic translation initiation factor 4E-binding protein 2 (4E-BP2), tumour necrosis factor alpha (TNF-α) and copper-zinc superoxide dismutase (Cu/Zn-SOD) gene expressions in the intestine of blunt snout bream, which may go further to explain the adverse effects of a deficient and/or an excess dietary threonine level on growth, immunity and health of fish. Furthermore, the present study also suggests that an optimum dietary threonine could play an important role in improving growth, enhancing immune function and maintaining health of fish.

Plasma and erythrocyte glutathione peroxidase activity, serum selenium concentration, and plasma total antioxidant capacity in cats with IRIS stages I-IV chronic kidney disease.

BACKGROUND: Serum selenium concentrations and the activity of plasma glutathione peroxidase (GPx) decrease with the progression of chronic kidney disease (CKD) in human patients. Selenium is considered a limiting factor for plasma GPx synthesis. Plasma total antioxidant capacity (TAC) is decreased in CKD cats in comparison to healthy cats. HYPOTHESIS: Serum selenium concentrations and plasma and erythrocyte GPx activity in cats with CKD are lower than in healthy cats. Serum selenium concentrations, the activity of enzymes, and plasma TAC progressively decrease with the progression of kidney disease according to IRIS (International Renal Interest Society) classification. ANIMALS: Twenty-six client-owned cats in IRIS stages I-IV of CKD were compared with 19 client-owned healthy cats. METHODS: A CBC, serum biochemical profile, urinalysis, plasma and erythrocyte GPx activity, serum selenium concentration, and plasma TAC were measured in each cat. RESULTS: Cats in IRIS stage IV CKD had a significantly higher (P = .025) activity of plasma GPx (23.44 ± 6.28 U/mL) than cats in the control group (17.51 ± 3.75 U/mL). There were no significant differences in erythrocyte GPx, serum selenium concentration, and plasma TAC, either among IRIS stages I-IV CKD cats or between CKD cats and healthy cats. CONCLUSIONS AND CLINICAL IMPORTANCE: Erythrocyte GPx activity, serum selenium concentration, and plasma TAC do not change in CKD cats compared with healthy cats. Selenium is not a limiting factor in feline CKD. Increased plasma GPx activity in cats with stage IV CKD suggests induction of antioxidant defense mechanisms. Antioxidant defense systems might not be exhausted in CKD in cats.

[Effects of cornel iridoid glycoside on activity of cholinesterases in vitro].

The purpose of the present study was to investigate the effects of cornel iridoid glycoside (CIG) on the activity of cholinesterases in vitro, and to investigate the mechanism of CIG's treating Alzheimer's disease (AD). The sources of cholinesterases were prepared from human blood cells, rat brain homogenate and human blood plasma, respectively. The biochemical methods were used to detect the activity of acetylcholine esterase (AChE) and butyryl cholinesterase (BuChE) to investigate the influence of CIG on cholinesterases. The results showed that CIG inhibited the activity of AChE of human blood cells and rat brain homogenate, with the 50% inhibition rate (IC50) of 1.6 g . L-1 and 3.3 g . L-1, respectively; and the inhibition of AChE of CIG is reversible. CIG also inhibited the activity of BuChE of human blood plasma, with the IC50 of 2.9 g . L-1. In conclusion, CIG can inhibit the activity of AChE and BuChE in vitro, which may be one of the mechanisms of CIG to treat AD.

Evaluation of antihepatotoxic potential of Solanum xanthocarpum fruit extract against antitubercular drugs induced hepatopathy in experimental rodents.

OBJECTIVE: To assess the hepatoprotective effect of Solanum xanthocarpum (S. xanthocarpum) fruit extract against antitubercular drug-induced liver toxicity in experimental animals. METHODS: Ethanolic (50%) fruit extract of S. xanthocarpum (100, 200 and 400 mg/kg bw) was administered daily for 35 days in experimental animals. Liver toxicity was induced by combination of three antitubercular drugs [isoniazid (I) 7.5 mg/kg, rifampicin (R) 10 mg/kg and pyrazinamide (P) 35 mg/kg] given orally as suspension for 35 days in rats. The hepatoprotective activity was assessed using various biochemical parameters like aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatise (ALP), total bilirubin (TBL), albumin (ALB), total protein (TP), lactate dehydroginase (LDH), and serum cholesterol (CHL). Meanwhile, in vivo antioxidant activities as lipid peroxidation (LPO), reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) were measured in rat liver homogenate. The biochemical observations were supplemented by histopathological examination. RESULTS: The results demonstrated that treatment with S. xanthocarpum significantly (P<0.05-P<0.001) and dose-dependently prevented drug induced increase in serum levels of hepatic enzymes. Furthermore, S. xanthocarpum significantly (up to P<0.001) reduced the LPO in the liver tissue and restored activities of defence antioxidant enzymes GSH, SOD and CAT towards normal levels. Histopathology of the liver tissue showed that S. xanthocarpum attenuated the hepatocellular necrosis and led to reduction in inflammatory cells infiltration. CONCLUSIONS: The results of this study strongly indicate the protective effect of S. xanthocarpum against liver injury which may be attributed to its hepatoprotective activity, and thereby scientifically support its traditional use.

Correlation between antibutyrylcholinesterasic and antioxidant activities of three aqueous extracts from Tunisian Rhus pentaphyllum.

For centuries, plants have been used in traditional medicines and there has been recent interest in the chemopreventive properties of compounds derived from plants. In the present study, we investigated the antibutyrylcholinestrasic (anti-BuChE) and antioxidant (against some free radicals) activities of extracts from Rhus pentaphyllum. Aqueous extracts were prepared from powdered R. pentaphyllum roots, leaves and seeds and characterized for the presence of tannins, flavonoids and coumarins. Seeds aqueous extract contained the highest quantities of both flavonoids and tannins (21.12% and 17.45% respectively). In the same way, seeds extracts displayed remarkable inhibition against BuChE over 95%, at 100 µg/ml and with IC50 0.74 µg/ml. In addition, compared to leaves and roots extracts, seeds aqueous extract revealed relatively strong antiradical activity towards the ABTS.+ (IC50 = 0.25 µg/ml) and DPPH (IC50 = 2.71 µg/ml) free radicals and decreased significantly the reactive oxygen species such O2.- (IC50 = 2.9 µg/ml) formation evaluated by the non-enzymatic generating O2.- system (Nitroblue tetrazolium/riboflavine). These data suggest that the anti-BuChE activities mechanism of these extracts occurs through a free radical scavenging capacities.The present study indicates that extracts of Rhus pentaphyllum leaves, seeds and roots are a significant source of compounds, such as tannins, flavonoids and coumarins, with anti-BuChE and antioxidant activities, and thus may be useful for chemoprevention.

Effect of dietary organic microminerals on starter pig performance, tissue mineral concentrations, and liver and plasma enzyme activities.

Weanling pigs (n = 160) were used to evaluate dietary essential microminerals (Cu, Fe, Mn, Se, and Zn) on performance, tissue minerals, and liver and plasma enzymatic activities during a 35-d postweaning period. A randomized complete block design with 5 treatments and 8 replicates was used in this study. Organic microminerals were added to complex nursery diets at 0 (basal), 50, 100, or 150% of the requirements of microminerals listed by the 1998 NRC. A fifth treatment contained inorganic microminerals at 100% NRC and served as the positive control. Pigs were bled at intervals with hemoglobin (Hb), hematocrit (Hct), glutathione peroxidase, and ceruloplasmin activities determined. Six pigs at weaning and 1 pig per pen at d 35 were killed, and the liver, heart, loin, kidney, pancreas, and the frontal lobe of the brain were collected for micromineral analysis. The liver was frozen in liquid N for determination of enzymatic activities. The analyzed innate microminerals in the basal diet met the NRC requirement for Cu and Mn but not Fe, Se, and Zn. Performance was not affected from 0 to 10 d postweaning, but when microminerals were added to diets, ADG, ADFI, and G:F improved (P < 0.01) from 10 to 35 d and for the overall 35-d period. Pigs fed the basal diet exhibited parakeratosis-like skin lesions, whereas those fed the supplemental microminerals did not. This skin condition was corrected after a diet with the added microminerals was fed. When the basal diet was fed, Hb and Hct declined, but supplemental microminerals increased Hb and Hct values. Liver catalase activity increased (P < 0.01) when microminerals were fed. The Mn superoxide dismutase activity tended to decline quadratically (P = 0.06) when supplemental microminerals were fed above that of the basal diet. Liver plasma glutathione peroxidase activities were greater (P < 0.01) when dietary organic and inorganic micromineral were fed. Liver concentrations of microminerals increased linearly (P < 0.01) as dietary microminerals increased, indicating that the liver was the primary storage organ. Micromineral tissue concentrations were least in pigs fed the basal diet and increased (quadratic, P < 0.01) to the 50% level of organic microminerals in the various tissues collected. The results indicated that innate microminerals, Cu and Mn, from a complex nursery diet may meet the micromineral needs of the weaned pig, but the need for Fe, Se, or Zn was not met by the basal diet.

Increased H2O2 level in exhaled breath condensate in primary breast cancer patients.

PURPOSE: This study was designed to assess exhaled hydrogen peroxide (H(2)O(2)), blood serum antioxidant capacity, and tumor necrosis factor-alpha (TNFalpha) in primary breast cancer (PBC). METHODS: The study included 34 consecutive, non-smoking PBC patients (aged 62.5 +/- 13.5 at surgery) prior to the treatments, qualified for modified radical mastectomy and not undergoing any adjuvant systemic therapy, and 33 healthy controls. The post surgery pathological assessment included tissue expression of estrogen (ER) and progesterone (PR) receptors, and epidermal growth factor receptor type 2 (HER-2/neu). Exhaled H(2)O(2) was determined fluorometrically in the exhaled breath condensate (EBC). Blood serum antioxidant capacity and TNFalpha levels were assessed with ferric reducing ability of plasma (FRAP) and ELISA immunoassay, respectively. RESULTS: In PBC patients, 10 ER, 11 PR, and 9 HER-2/neu positive tumors were identified and HER-2/neu score was 2+ in 20% of all tumors. Median (Me) H(2)O(2) was increased up to 0.44 microM (interquartile range IR: 0.20-1.25 microM) compared with healthy control of 0.36 microM (IR: 0.12-0.48 microM; p < 0.05). The H(2)O(2) concentration in EBC was significantly correlated (tau = 0.27; p = 0.03) and increased in cases with nodal metastases (n = 12; p = 0.04). Serum TNFalpha was increased up to 51.7 +/- 21.0 pg/ml compared with controls 17.2 +/- 3.65 pg/ml (p < 0.05). FRAP was increased to 1.41 +/- 0.37 mM Fe(2+) compared with control 1.19 +/- 0.17 mM Fe(2+); (p = 0.006). CONCLUSIONS: This is the first study to demonstrate increased H(2)O(2) in exhaled breath condensate in patients with localized breast malignancy and its relation with clinical severity.

Effects of dietary phospholipid level in cobia (Rachycentron canadum) larvae: growth, survival, plasma lipids and enzymes of lipid metabolism.

A study was conducted to determine the effects of dietary phospholipid (PL) levels in cobia (Rachycentron canadum) larvae with regard to growth, survival, plasma lipids and enzymes of lipid metabolism. Fish with an average weight of 0.4 g were fed diets containing four levels of PL (0, 20, 40 and 80 g kg(-1)dry matter: purity 97%) for 42 days. Final body weight (FBW), weight gain (WG) and survival ratio were highest in the 8% PL diet group and mortality was highest in PL-free diet group. We examined the activities of lipoprotein lipase (LPL) and hepatic lipase (HL) in liver, lecithin-cholesterolacyltransferase (LCAT) in plasma as well as plasma lipids and lipoprotein. LCAT activity showed a decrease of more than two-fold in PL-supplemented diet groups compared with the PL-free diet group. HL activity was highest in the 8% PL diet group and the other three groups showed no difference. LPL activity was significantly higher in the PL-supplemented diet groups than in the PL-free diet group. The dietary intervention significantly increased plasma phospholipids and total cholesterol (TC) levels, and the higher free cholesterol (FC) level contributed to the TC level. However, the fish fed PL exhibited a significantly decreased plasma triglyceride (TG) level. The lipoprotein fractions were also affected significantly by the PL. The PL-supplemented diet groups had significantly higher high-density lipoprotein (HDL) compared with the PL-free diet group, but showed a marked decrease in very low-density lipoprotein (VLDL). The results suggested that PL could modify plasma lipoprotein metabolism and lipid profile, and that the optimal dietary PL level may well exceed 80 g kg(-1) for cobia larvae according to growth and survival.

Inhibition of thrombin generation in recalcified plasma.

Eight inhibitors of thrombin generation were compared in recalcified unfrozen plasma. Individual or pooled normal citrated plasma was supplemented on polystyrol flat-bottom wells (23 degrees C) with increasing concentrations of low-molecular-weight heparin, heparin, danaparoid, fondaparinux, hirudin, argatroban, corn trypsin inhibitor, or aprotinin. Thrombin was generated by addition of 5 microl fresh 250 mmol/l CaCl2 to 50 microl plasma in polystyrol flat-bottom wells and incubation for 20 min at 37 degrees C (recalcified coagulation activity assay). Arginine stopped hemostasis activation and then the generated thrombin activity was specifically quantified. The approximate 50% inhibitory concentrations of plasmatic anticoagulants for individual or pooled normal plasma are, respectively, 0.6 or 3.7 mIU/ml low-molecular-weight heparin, 0.3 or 1.6 mIU/ml heparin, 0.7 or 6.1 mU/ml danaparoid, 0.023 or 0.18 microg/ml fondaparinux, 75 or 230 pg/ml hirudin, 0.026 or 0.24 microg/ml argatroban, 1 or 2 U/ml corn trypsin inhibitor, and 2 or 4 KIU/ml aprotinin. The 50% inhibitory concentration values for corn trypsin inhibitor or aprotinin at plasmatic concentrations above 4-100 U/ml might increase pathologically the thrombin generation. The recalcified coagulation activity assay is a sensitive method to measure prothrombotic tendencies of blood or subtle concentrations of any plasmatic anticoagulant. It is suggested to analyze the individual patient's sensibility to certain plasmatic anticoagulants.

Differential effects of acetaminophen on enzymatic and non-enzymatic antioxidant factors and plasma total antioxidant capacity in developing and adult rats.

Recently we reported that ferric reducing ability of plasma (FRAP) assay, as an index of total antioxidant activity, increases in growing rats in response to high dose of vitamin K. In this study, it was found that acetaminophen (APAP) can cause elevation in FRAP in suckling and adult rats. This study was initiated to assess the contribution of individual antioxidant factors on elevation in FRAP. A surge in FRAP, 1 h after high dose APAP (250 or 450 mg/kg BW) administration was recorded in both young as well as adults. Whereas, low dose drug (25 mg/kg) failed to alter FRAP in both the age groups. Time-course studies show that drug-dependent elevation in FRAP begin rapidly, reaching a maximum at 1 h (> 500%). Increased FRAP was associated with a marked increase (approximately 14-fold) in plasma bilirubin, 6 h after drug administration at 450 mg/kg only in suckling rats. Similarly, APAP-related increase in superoxide dismutase activity in erythrocytes was limited to young rats of both the age groups. Other factors measured during this period viz., plasma uric acid, bilirubin and total protein together with catalase activity of erythrocytes remained unchanged in treated rats. Under these circumstances, APAP-related depletion in liver glutathione was almost similar in both the age groups. During a 12 h study, the concentration of lipid peroxidation products, in liver of treated groups remained within the levels of respective controls. The endpoint hepatotoxic effects of APAP was almost similar in both the age groups, suggesting that like adults, immature rats can cope with toxic effects of APAP owing to their drug-dependent induction in certain antioxidant factors.

Coffee consumption induces GSTP in plasma and protects lymphocytes against (+/-)-anti-benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide induced DNA-damage: results of controlled human intervention trials.

A number of animal studies indicate that coffee protects against chemical induction of cancer; also human studies suggest that coffee consumption is inversely related with the incidence of different forms of cancer. The protective effects were attributed to induction of glutathione-S-transferases (GSTs) and aim of the present human study was to find out if coffee causes induction of GSTs and protects against DNA-damage caused by (+/-)-anti-B[a]P-7,8-dihydrodiol-9,10-epoxide (BPDE), the DNA-reactive metabolite of benzo(a)pyrene. Ten participants consumed 1L unfiltered coffee/d over 5 days. Before and after the intervention, saliva and blood were collected and the overall GST activity was measured with 1-chloro-2,4-dinitrobenzene (CDNB). Additionally, GSTP and GSTA were determined in plasma with immunoassays. In blood, only weak (p=0.042) induction of GST (CDNB) was found. Furthermore, pronounced (three-fold) induction of GSTP was observed in blood, whereas GSTA was not altered. No correlations were seen between induction of GST (CDNB) and GSTP activities and the GSTP1 genotypes of the participants. Also clinical parameters (creatinine, alanine, aminotransferase, aspartate aminotransferase, alkaline phosphatase), which are markers for organ damage, were monitored. None of them was altered by coffee, but serum cholesterol levels were slightly (not significantly) enhanced. In a second trial (n=7), GSTP induction by unfiltered and paper filtered coffees, differing in cafestol and kahweol contents, were compared. The participants consumed 1L coffee/d over 3 days. Again significant (three-fold) induction of GSTP was observed. The effects seen with the two coffees were identical, indicating that the diterpenoid concentrations are not responsible for the effects. In a further trial (n=7), the effect of coffee (unfiltered, 1L/d, 5 days) on BPDE induced DNA-migration was studied in comet assays. A 45% reduction effect was observed. Our findings show that coffee induces GSTP in humans and indicate that consumption may lead to protection towards polycyclic aromatic hydrocarbons.

Plasma and erythrocyte selenium and glutathione peroxidase activity in preterm infants at risk for bronchopulmonary dysplasia.

The purpose of this study was to examine the relationships between selenium status, as measured by plasma and erythrocyte selenium and glutathione peroxidase (GPx) activity, and other postnatal factors, including selenium intake, gestational age, and oxygen dependence in preterm infants at risk for bronchopulmonary dysplasia. Eighteen preterm infants of 30 wk gestational age or less were included. At postnatal wk 1 and 4, selenium concentrations and GPx activity were measured and oxygen dependence and daily selenium intakes were determined from the medical chart. Plasma and erythrocyte selenium concentrations decreased from wk 1 to wk 4, whereas erythrocyte GPx activity increased. Increased selenium intakes during wk 1 were associated with increased erythrocyte GPx activity at both time-points, as well as a decreased need for supplemental oxygen on d 28. Preterm infants display increasing erythrocyte GPx activity despite declines in plasma and erythrocyte selenium. GPx activity might be enhanced by very early selenium supplementation.

Platelet inhibitory effect of nitroglycerin in platelet-rich plasma: relevance of glutathione-s-transferases in plasma.

BACKGROUND: Nitroglycerin (NTG) is believed to exert its platelet inhibitory effect via its biotransformation to nitric oxide (NO). We examined the relevance of glutathione-s-transferases (GST) in plasma in the conversion of NTG to NO and the platelet inhibitory effect of NTG. METHODS AND RESULTS: Nitroglycerin (1-100 micrograms/mL) was incubated with human platelet-rich plasma (PRP) for 10-60 minutes. Nitroglycerin caused a concentration-dependent inhibition of platelet aggregation in PRP with IC50 approximately 50 micrograms/mL. NTG also enhanced nitrite levels in PRP and stimulated cyclic GMP accumulation in platelets. In contrast, when NTG was incubated with washed platelets (WP) in concentrations as high as 100 micrograms/mL, there was no inhibition of platelet aggregation, formation of nitrite, or accumulation of cGMP. However, treatment of WP suspension with authentic NO exhibited diminished platelet aggregation, suggesting that NTG delivers NO in plasma that subsequently inhibits platelet aggregation. In keeping with this concept, the aggregation inhibitory effect of NTG in PRP was blocked by oxyhemoglobin. The platelet aggregation inhibition by NTG was potentiated by propylthiouracil (600 micrograms/mL), a GST inducer, and antagonized by ketoprofen (100 micrograms/mL), a GST inhibitor. Direct measurement indeed showed significant GST activity in plasma (24 +/- 3 mU/mL). CONCLUSIONS: We suggest that NTG inhibits platelet aggregation in PRP by its biotransformation to NO in plasma. The presence of GST, and perhaps other cofactors, in plasma is relevant in the platelet inhibitory effects of NTG in PRP.

Potent activation of nitric oxide synthase by garlic: a basis for its therapeutic applications.

Garlic (Allium sativum L.) is thought to have a variety of therapeutic applications including inhibition of platelet aggregation. Many of the therapeutic actions of garlic parallel the physiological effects of nitric oxide and may be explained by its ability to increase nitric oxide synthase activity intracellularly. Our studies showed that both water and alcoholic extracts of garlic are very potent inhibitors of platelet aggregation induced by epinephrine and ADP. Similar dilutions of garlic extract also activated nitric oxide synthase activity in isolated platelets in vitro. The same extract was also very effective in activating nitric oxide synthase activity in placental villous tissue. The addition of garlic extracts increased nitric oxide synthase activity in a dose-dependent manner. Nitrite levels in the supernatants of incubated placental villous tissue were similarly increased. Activation of calcium-dependent nitric oxide synthase and the subsequent production of nitric oxide is probably the most novel mechanism yet claimed by which garlic can exert its therapeutic properties.

Long-term supplementation with selenate and selenomethionine: selenium and glutathione peroxidase (EC 1.11.1.9) in blood components of New Zealand women.

Thirty-three New Zealand women aged 18-23 years received daily for 32 weeks, 200 micrograms Se as Se-enriched yeast (selenomethionine), or brewer's yeast mixed with selenate, or no added Se (placebo) in a double-blind trial. Se supplementation raised (P = 0.001) platelet glutathione peroxidase (EC 1.11.1.9; GSHPx) activity, and also Se and GSHPx in whole blood, erythrocytes and plasma. Selenomethionine was more effective in raising blood Se concentrations than selenate, but both were equally effective in raising GSHPx activities in whole blood, erythrocytes and plasma, indicating a similar bioavailability for the two forms. These observations and those of gel filtration studies of erythrocytes and plasma proteins reported elsewhere (Butler et al. 1991) are consistent with the incorporation of Se from selenomethionine into a general tissue protein pool while selenate is directly available for GSHPx synthesis, and explain the poorer correlation between Se and GSHPx in individuals with higher Se status. However, selenate raised platelet GSHPx activities to a greater extent than did selenomethionine suggesting some other effect of selenate on platelets which needs further investigation. A response of GSHPx activity in these New Zealand subjects indicates that their dietary Se intake is insufficient to meet recommended intakes based on the criterion of saturation of GSHPx activity, and could reflect a marginal Se status. The level of blood Se necessary for saturation of GSHPx of about 100 ng Se/ml whole blood confirms observations in earlier studies.