Rifting and subduction records of the Paleo–Tethys in North Laos: Constraints from Late Paleozoic mafic and plagiogranitic magmatism along the Song Ma tectonic zone

2020 ◽  
Vol 133 (1-2) ◽  
pp. 212-232 ◽  
Author(s):  
Yuzhi Zhang ◽  
Xue Yang ◽  
Yuejun Wang ◽  
Xin Qian ◽  
Yukun Wang ◽  
...  
Keyword(s):  
South China ◽  
Southwest China ◽  
Hainan Island ◽  
Suture Zone ◽  
Published Data ◽  
Tectonic Zone ◽  
Group 3 ◽  
Group 2 ◽  
Subduction Setting ◽  
Group 1

Abstract In Southeast Asia, the Jinshajiang–Ailaoshan suture in Southwest China and the Song Ma zone in Vietnam were generally accepted as the amalgamation boundary of the South China and Simao/Indochina blocks. However, the tectonic location of the Paleotethyan suture in North Laos and its tectonic affinity remain ambiguous. To address this issue, we present the geochemical and geochronological data of a set of mafic and plagiogranitic rocks along the Song Ma suture zone in North Laos. Three groups of rocks with distinctive petrological, geochronological, and geochemical signatures were identified. The ca. 370 Ma Group 1 plagioclase amphibolite was preserved as xenoliths in the ca. 260 Ma granitoids. It exhibits a normal mid–oceanic–ridge basalt (N–MORB)-like, multi-elemental pattern with highly positive εNd(t) (+3.3 to +10.7) and εHf(t) (+6.68 to +7.41) values and low δ18O values (5.3‰−5.5‰), that are interpreted as products of the Late Devonian − earliest Carboniferous continental rift setting. The ca. 270 Ma Group 2 gabbro/diabase–diorite exhibits arc-like geochemical affinity with the εNd(t), εHf(t), and δ18O values of –5.85 to –3.76, –3.8 to +3.2, and 6.6‰–7.6‰, respectively. It is derived from the metasomatized wedge. The ca. 260 Ma Group 3 plagiogranite shows Nb-Ta and Ti negative anomalies and positive εNd(t) (+3.21 to +4.21), εHf(t) (+8.4 to +13.6), and δ18O (5.9‰−6.8‰) values, which are indicative of its derivation from mafic oceanic crust in a subduction setting. In combination with the published data, these results support the development of the Carboniferous–Permian Paleotethyan branch in North Laos, which represents the tectonic location of the Song Ma suture zone that spatially connects the Jinshajiang–Ailaoshan suture zone in Southwest China and the Chenxing–Bangxi suture zone in Hainan Island, South China.

Permo–Triassic granitoids, Hainan Island, link to Paleotethyan not Paleopacific tectonics

2020 ◽  
Vol 132 (9-10) ◽  
pp. 2067-2083 ◽  
Author(s):  
Huiying He ◽  
Yuejun Wang ◽  
Peter A. Cawood ◽  
Xin Qian ◽  
Yuzhi Zhang ◽  
...  
Keyword(s):  
Hainan Island ◽  
Late Triassic ◽  
Geochemical Data ◽  
Calc Alkaline ◽  
Isotopic Data ◽  
Tectonic Zone ◽  
Group 3 ◽  
Group 2 ◽  
T Values ◽  
Group 1

Abstract Hainan Island may have lain at the boundary between the Tethyan and Pacific domains since the late Paleozoic. Permo–Triassic granitoids outcropped on the island provide insight into Mesozoic tectonic evolution and potential dynamics. Based on analyses of zircon U-Pb geochronological and Hf-O isotopic data, along with whole-rock elemental and Sr-Nd isotopic data, the Permo–Triassic granitoids are divided into three groups: Late Permian (256–252 Ma) gneissic granitoids (Group 1), Early–Middle Triassic (247–244 Ma) massive granitoids (Group 2), and Middle-Late Triassic (242–225 Ma) massive granitoids (Group 3). Groups 1 and 2 exhibit similar elemental and Sr-Nd isotopic compositions with εNd(t) values ranging from –6.71 to –3.25. Group 1 is characterized by gneissic foliation and calc-alkaline I-type geochemical affinities with negative Nb-Ta and Ti anomalies; it has low εHf(t) (–4.2∼+0.2) and high δ18O values (9.35–10.46‰), possibly related to derivation of a metabasite source in a continental arc setting. The Group 2 samples are peraluminous massive granitoids with slightly high A/CNK ratios of 1.00–1.31, δ18O values (8.85–11.75‰), and high Sr/Y ratios but low εHf(t) (–8.7∼+1.6) values. They may have originated from the mixed source of greywacke and metabasite, indicating a compressive tectonic setting. The Group 3 high-K calc–alkaline granitoids have high zircon temperatures (842–867 °C) and show the geochemical signatures of A-type granites. They are featured by slightly low whole-rock εNd(t) and zircon εHf(t) values, suggestive of the derivation from a metabasite–greywacke source in an extensional setting. In combination with other geochronological and geochemical data from Hainan Island, it is proposed that the Permian–Triassic igneous magmatism in Hainan Island reflects a continuous amalgamation process from back-arc consumption (272–252 Ma) to orogenic assembly (251–243 Ma) and orogenic collapse (242–225 Ma) between the South China and Indochina Blocks. Such a temporal–spatial pattern for the Hainan granitoids is consistent with that along the Truong Son, Jinshajiang–Ailaoshan–Song Ma tectonic zone, suggesting dominant control of Paleotethyan domain instead of Paleopacific tectonics.

Atomoxetine, thioridazine, pipophezine in treatment adolescents with ADHD

2015 ◽  
Vol 6 (2) ◽  
pp. 39-44
Author(s):  
Vita Valentinovna Glushchenko
Keyword(s):  
Published Data ◽  
Nucleotide Substitutions ◽  
Hyperkinetic Syndrome ◽  
Single Nucleotide ◽  
Hyperactivity Disorder ◽  
Organic Failure ◽  
Group 3 ◽  
Group 2 ◽  
Main Components ◽  
Group 1

Analysis of published data on the diagnostic criteria used in the qualification of hyperkinetic syndrome found that along with the data on residual-organic failure CNS causes the development of hyperkinetic syndrome expanded range of studies on the endogenous nature of this syndrome. Thus the international “Genomics Consortium psychiatric” (Psychiatric Genomics Consortium) identify common loci in hyperkinetic disorder and schizophrenia which are located on the short arm of the 3rd chromosome (3r21) and on the long arm of chromosome 10 (10q24) and revealed single nucleotide substitutions (SNPs) in the two genes (CACNA1C and CACNB2) which encode proteins that are part of the channels regulating calcium transport into brain cells. Hyperactivity disorder (GR) as a mental disorder (F90) is multifactorial in nature, which requires consideration of clinical symptom in different planes with the release of endogenous and exogenous forms the primary etiological factor for differentiation therapy. Were studied 231 adolescents with a diagnosis of “Attention-Deficit hyperactivity Disorder” (mean age - 17,7 years). The main components of adolescents AHHD are given by BPRS: arousal (3,63 ± 0,06); cognitive (2,94 ± 0,06) and emotional (2,64 ± 0,06) disorder. Patients were split into threatment group: group 1 (n = 23) received Atomoxetine 25mg/day; group 2 (n = 20) received thioridazine 25mg/day, group 3 (n = 22) - pipophezine 50 mg/day. The positive dynamics of disregulatory-motor typeractivity, cognitive and emotional components of ADHD was observed. The aim: to evaluate the influence of Atomoxetine, Thioridazine, Pipophezine on the main psychopatological clinical-components of adolescents AHHD.

scholarly journals Superinfection with Difficult-to-Treat Pathogens Significantly Reduces the Outcome of Periprosthetic Joint Infections

Antibiotics ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1145
Author(s):  
Ali Darwich ◽  
Franz-Joseph Dally ◽  
Khaled Abu Olba ◽  
Elisabeth Mohs ◽  
Sascha Gravius ◽  
...  
Keyword(s):  
Joint Infection ◽  
Published Data ◽  
Joint Infections ◽  
Group 4 ◽  
Single Center Study ◽  
Group 3 ◽  
Group 2 ◽  
Related Mortality ◽  
Group 1

Periprosthetic joint infection (PJI) is a serious complication after total joint arthroplasty. In the course of a PJI, superinfections with pathogens that do not match the primary infecting micro-organism may occur. To our knowledge, there are no published data on the outcome of such infections in the literature. The aim of this study was to assess the outcome of PJI with superinfections with a difficult-to-treat (DTT) pathogen. Data of 169 consecutive patients with PJI were retrospectively analyzed in this single-center study. Cases were categorized into: Group 1 including non-DTT-PJI without superinfection, Group 2 DTT-PJI without superinfection, Group 3 non-DTT-PJI with DTT superinfection, and Group 4 non-DTT-PJI with non-DTT superinfection. Group 3 comprised 24 patients and showed, after a mean follow-up of 13.5 ± 10.8 months, the worst outcome with infection resolution in 17.4% of cases (p = 0.0001), PJI-related mortality of 8.7% (p = 0.0001), mean revision rate of 6 ± 3.6 (p < 0.0001), and duration of antibiotic treatment of 71.2 ± 45.2 days (p = 0.0023). PJI caused initially by a non-DTT pathogen with a superinfection with a DTT pathogen is significantly associated with the worst outcome in comparison to non-DTT-PJI, PJI caused initially by a DTT pathogen, and to non-DTT-PJI with a non-DTT superinfection.

Early Neoproterozoic continental arc system at the central Jiangnan Orogen, South China: Geochronological and geochemical constraints on the key igneous rock-association

2019 ◽  
Vol 132 (3-4) ◽  
pp. 638-654 ◽  
Author(s):  
Yuzhi Zhang ◽  
Yuejun Wang
Keyword(s):  
South China ◽  
Basaltic Andesite ◽  
Tholeiitic Basalt ◽  
Primitive Mantle ◽  
Continental Arc ◽  
Origin Group ◽  
Group 3 ◽  
Group 2 ◽  
Early Neoproterozoic ◽  
Group 1

Abstract To better reveal the tectonic process of the Jiangnan Orogen in creating the united South China Block (SCB), a set of new geochronological, geochemical, and Sr-Nd-Hf-O isotopic data is herein presented for the coeval early Neoproterozoic mafic to acid rocks in the Lengjiaxi Group and its equivalents. Our data show that these rocks belong to subalkaline basalt, basaltic andesite, andesite, and dacite in composition, and can be geochemically classified into N-MORB- and arc-like mafic (Group 1 and Group 2, respectively), along with high-Mg andesitic-dacitic (Group 3) rocks. They yield zircon U-Pb ages of 837 ± 4 Ma, 832 ± 11 Ma, and 835 ± 7 Ma, respectively, suggesting their early Neoproterozoic (ca. 835 Ma) origin. Group 1 has SiO2 = 47.21–52.45 wt%, MgO = 7.36–10.07 wt% with Mg-number of 56–68, 87Sr/86Sr(t) = 0.7062–0.7136 and εNd(t) = +1.3–+9.4, along with N-MORB-like REE- (rare earth element) and PM (primitive mantle)-normalized patterns, suggesting its derivation from a refractory MORB-like source newly introduced by slab-derived fluid. The Group 2 samples are classified as tholeiitic basalt and basaltic andesite with SiO2 = 48.78–55.75 wt%, MgO = 7.70–12.74 wt%, Mg-number = 63–77, 87Sr/86Sr(t) = 0.7046–0.7098 and εNd(t) = –1.6 to –0.4. They exhibit similar “spiky” REE- and PM-normalized patterns to typical arc basalt, with pronounced enrichment in (large ion lithophile elements) and sharp depletion in (high field strength elements), probably inheriting from a sub-arc source modified by fluids and/or melts released from recycled sedimentary component. The Group 3 rocks show SiO2 = 57.74–66.30 wt%, FeOt = 6.22–8.59 wt%, Mg-number = 43–66, K2O+Na2O = 3.18–6.17 wt% with K2O/Na2O of 0.59–3.28, classified as high-Mg andesites and dacites. Diagnostic elemental and isotopic ratios of Group 3 include (La/Yb)cn = 7.7–11.4, (Gd/Yb)cn = 1.44–1.87, Eu/Eu* = 0.49–0.80, Nb/La = 0.27–0.42 and εNd(t) = –7.3 to –5.4, resembling to those of other early Neoproterozoic high-Mg intermediate rocks in the SCB, originating from a mantle wedge source with proportional addition of the recycled SCB sediment-derived components. In combination with the available data and geological observations, it is concluded that the N-MORB- and arc-like mafic, along with high-Mg andesitic rocks are coeval in the Lengjiaxi Group and its equivalents along the central Jiangnan Orogen and formed at ca. 847–832 Ma of the early Neoproterozoic period. The synthesis of these observations suggests the development of an early Neoproterozoic continental arc-basin setting. The arc-basin system westerly subducted and finally closed at ca. 830 Ma and the assembly of the Yangtze and Cathaysia blocks terminated at ca. 810 Ma along the central Jiangnan Orogen.

In-vivo evaluation of the effect of cyanoacrylate on prosthetic vascular graft infection – does cyanoacrylate increase the severity of infection?

VASA ◽  
2020 ◽  
Vol 49 (4) ◽  
pp. 281-284
Author(s):  
Atıf Yolgosteren ◽  
Gencehan Kumtepe ◽  
Melda Payaslioglu ◽  
Cuneyt Ozakin
Keyword(s):  
Vascular Graft ◽  
Graft Infection ◽  
Vascular Graft Infection ◽  
Group 4 ◽  
Significant Difference ◽  
Group 3 ◽  
Group 2 ◽  
Prosthetic Vascular Graft Infection ◽  
Group 1

Summary. Background: Prosthetic vascular graft infection (PVGI) is a complication with high mortality. Cyanoacrylate (CA) is an adhesive which has been used in a number of surgical procedures. In this in-vivo study, we aimed to evaluate the relationship between PVGI and CA. Materials and methods: Thirty-two rats were equally divided into four groups. Pouch was formed on back of rats until deep fascia. In group 1, vascular graft with polyethyleneterephthalate (PET) was placed into pouch. In group 2, MRSA strain with a density of 1 ml 0.5 MacFarland was injected into pouch. In group 3, 1 cm 2 vascular graft with PET piece was placed into pouch and MRSA strain with a density of 1 ml 0.5 MacFarland was injected. In group 4, 1 cm 2 vascular graft with PET piece impregnated with N-butyl cyanoacrylate-based adhesive was placed and MRSA strain with a density of 1 ml 0.5 MacFarland was injected. All rats were scarified in 96th hour, culture samples were taken where intervention was performed and were evaluated microbiologically. Bacteria reproducing in each group were numerically evaluated based on colony-forming unit (CFU/ml) and compared by taking their average. Results: MRSA reproduction of 0 CFU/ml in group 1, of 1410 CFU/ml in group 2, of 180 200 CFU/ml in group 3 and of 625 300 CFU/ml in group 4 was present. A statistically significant difference was present between group 1 and group 4 (p < 0.01), between group 2 and group 4 (p < 0.01), between group 3 and group 4 (p < 0.05). In terms of reproduction, no statistically significant difference was found in group 1, group 2, group 3 in themselves. Conclusions: We observed that the rate of infection increased in the cyanoacyrylate group where cyanoacrylate was used. We think that surgeon should be more careful in using CA in vascular surgery.

Abnormal Haemostasis and Blood Viscosity in Malignant Hypertension

1984 ◽  
Vol 52 (03) ◽  
pp. 253-255 ◽  
Author(s):  
C Isles ◽  
G D O Lowe ◽  
B M Rankin ◽  
C D Forbes ◽  
N Lucie ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Viscosity ◽  
Renal Damage ◽  
Antithrombin Iii ◽  
Plasma Viscosity ◽  
Malignant Hypertension ◽  
Fibrin Deposition ◽  
Group 3 ◽  
Group 2 ◽  
Group 1

SummaryWe have previously shown abnormalities of haemostasis suggestive of intravascular coagulation in patients with malignant hypertension, a condition associated with retinopathy and renal fibrin deposition. To determine whether such abnormalities are specific to malignant hypertension, we have measured several haemostatic and haemorheological variables in 18 patients with malignant hypertension (Group 1), 18 matched healthy controls (Group 2), and 18 patients with non-malignant hypertension (Group 3) matched for renal pathology, blood pressure and serum creatinine with Group 1. Both Groups 1 and 3 had increased mean levels of fibrinogen, factor VIIIc, beta-thrombo- globulin, plasma viscosity and blood viscosity (corrected for haematocrit); and decreased mean levels of haematocrit, antithrombin III and platelet count. Mean levels of fast antiplasmin and alpha2-macroglobulin were elevated in Group 1 but not in Group 3. We conclude that most blood abnormalities are not specific to malignant hypertension; are also present in patients with non-malignant hypertension who have similar levels of blood pressure and renal damage; and might result from renal damage as well as promoting further renal damage by enhancing fibrin deposition. However increased levels of fibrinolytic inhibitors in malignant hypertension merit further investigation in relation to removal of renal fibrin.

Features of postoperative period in patients with chronic venous insufficiency: phlebectomy versus thermal ablation

2020 ◽  
pp. 64-75
Author(s):  
E. Burleva ◽  
O. Smirnov ◽  
S. Tyurin
Keyword(s):  
Postoperative Period ◽  
Chronic Venous Insufficiency ◽  
Thermal Ablation ◽  
Venous Insufficiency ◽  
Clinical Symptoms ◽  
Varicose Veins ◽  
Statistical Processing ◽  
Group 3 ◽  
Group 2 ◽  
Group 1

The purpose of the study was to conduct a comparative assessment of the course of the postoperative period after phlebectomy and thermal ablation in patients with varicose veins of the lower extremities in the system of the great saphenous vein (GSV) with class C2 of chronic venous insufficiency (CVI) — CEAP class C2. Materials and methods: 455 patients (455 limbs) with CEAP class C2. Group 1 (n = 154) received stripping + minimally invasive phlebectomy; Group 2 — endovenous laser ablation (EVLA) of GSV trunk + sclerotherapy of varicose veins; 3 group (n = 150) — radiofrequency ablation (RFA) of the GSV + sclerotherapy. All patients were united by a single tactical solution — the elimination of pathological vertical reflux in GSV. In each group, patients were with similar hemodynamic profile were selected (Group 1 = 63; Group 2 = 61; Group 3 = 61). The course of the postoperative period (from 2 days to 2 months) was compared for pain (visual analog scale — VAS), clinical symptoms of chronic venous insufficiency, degree of satisfaction (Darvall questionnaire), and duration of disability. Statistical processing was carried out using Excel programs for Windows XP, MedCalc® (version 11.4.2.0., Mariakerke, Belgium). Results: Postoperative pain is more pronounced (during day 1 for Group 1–4.0, Group 2–3.0, Group 3–2.0) and more prolonged (up to 4 days) after open surgeries (p < 0.05). The dynamics of the clinical symptoms of CVI (including varicose syndrome and use of compression therapy) could not be fully evaluated in connection with the ongoing sclerotherapy procedures for patients of Groups 2 and 3. Satisfaction of patients with aesthetic aspects was higher than expected in all groups. Reliable statistical differences proved decrease in days of disability (Group 1–14; Group 2–4; Group 3–3) and earlier return to physical activities and work in patients after thermal ablation in comparison with phlebectomy. Conclusion: The study shows that all three methods for eliminating vertical reflux in the GSV can be proposed for a large category of patients with CEAP of class C3 and C2. Medical and social rehabilitation of patients using endovascular thermal ablation technologies proceeds faster, which is beneficial both for the patients and for society.

Analysis of the quality of early diagnostics of cardiovascular diseases in students of educational institutions of Khabarovsk (according to the data of preventive examinations)

2020 ◽  
pp. 13-16
Keyword(s):  
Blood Pressure ◽  
Cardiovascular Diseases ◽  
Sinus Tachycardia ◽  
Blood Pressure Level ◽  
Educational Institutions ◽  
Conduction Disturbances ◽  
Group 3 ◽  
Group 2 ◽  
Group 1

To identify the prevalence of early pathology of cardiovascular diseases, a survey of 400 200 girls) in the age group 15 and 17 years old was conducted as a part of routine medical of the level of blood pressure (BP) was carried out, with the calculation of the average level pressure on the basis of three separate measurements estimated by percentile tables for a registration of a standard resting ECG in 12 leads. According to the results of the survey, into 3 groups: with an increase in blood pressure above 95 ‰ (group 1 – 16 people), which recorded in males (p<0,05); Group 2 (67 people) – adolescents with a normal blood pressure level and group 3 of adolescents with a decrease in blood pressure below 5 ‰ changes in the form of rhythm and conduction disturbances were noted in almost every a predominance of sinus tachycardia in the first group. In the third group of adolescents, form of ectopic rhythm and pacemaker migration were significantly more frequently only 78 % of adolescents were referred for consultation and in-depth examination by a pediatric cardiologist.

Does Perioperative Hemoglobin A1c Level Affect the Incidence, Pattern and Mortality of Lower Extremity Amputation?

2019 ◽  
Vol 17 (4) ◽  
pp. 354-364
Author(s):  
Hassan Al-Thani ◽  
Moamena El-Matbouly ◽  
Maryam Al-Sulaiti ◽  
Noora Al-Thani ◽  
Mohammad Asim ◽  
...  
Keyword(s):  
Glycemic Control ◽  
Lower Extremity ◽  
Hazard Ratio ◽  
Lower Extremity Amputation ◽  
Group 4 ◽  
Group 3 ◽  
Group 5 ◽  
Group 2 ◽  
Extremity Amputation ◽  
Group 1

Background: We hypothesized that perioperative HbA1c influenced the pattern and outcomes of Lower Extremity Amputation (LEA). Methods: A retrospective analysis was conducted for all patients who underwent LEA between 2000 and 2013. Patients were categorized into 5 groups according to their perioperative HbA1c values [Group 1 (<6.5%), Group 2 (6.5-7.4%), Group 3 (7.5-8.4%), Group 4 (8.5-9.4%) and Group 5 (≥9.5%)]. We identified 848 patients with LEA; perioperative HbA1c levels were available in 547 cases (Group 1: 18.8%, Group 2: 17.7%, Group 3: 15.0%, Group 4: 13.5% and Group 5: 34.9%). Major amputation was performed in 35%, 32%, 22%, 10.8% and 13.6%, respectively. Results: The overall mortality was 36.5%; of that one quarter occurred during the index hospitalization. Mortality was higher in Group 1 (57.4%) compared with Groups 2-5 (46.9%, 38.3%, 36.1% and 31.2%, respectively, p=0.001). Cox regression analysis showed that poor glycemic control (Group 4 and 5) had lower risk of mortality post-LEA [hazard ratio 0.57 (95% CI 0.35-0.93) and hazard ratio 0.46 (95% CI 0.31-0.69)]; this mortality risk persisted even after adjustment for age and sex but was statistically insignificant. The rate of LEA was greater among poor glycemic control patients; however, the mortality was higher among patients with tight control. Conclusion: The effects of HbA1c on the immediate and long-term LEA outcomes and its therapeutic implications need further investigation.

Cholinesterase Activities and Oxidative Stress in Cattle Experimentally Exposed to Nitrate/Nitrite in Cultivated Pasture with Different Fertilization Schemes

2018 ◽  
Vol 46 (1) ◽  
Author(s):  
Ricardo Christ ◽  
Aleksandro Schafer Da Silva ◽  
Mateus Eloir Grabriel ◽  
Luan Cleber Henker ◽  
Renan Augusto Cechin ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Enzyme Activity ◽  
Cholinesterase Activity ◽  
Blood Samples ◽  
Group 3 ◽  
Cholinesterase Activities ◽  
Group 2 ◽  
Nitrate And Nitrite ◽  
And Oxidative Stress ◽  
Group 1

  Background: Nitrate and nitrite poisoning is associated with pasture intake that has high nitrate levels and leads to acute methemoglobinemia. Pasture may accumulate nitrate under certain conditions, such as excessively fertilized soil or en­vironmental conditions that enhance the N absorption (rain preceded by a period of drought). After ingestion of plants, this substrate reaches the rumen and, in physiological conditions, is reduced to nitrite and afterward to ammonia. The aim of this study was to evaluate changes in cholinesterase activities and oxidative stress caused by subclinical poisoning for nitrate and nitrite in cattle fed with Pennisetum glaucum in three different fertilization schemes. Materials, Methods & Results: In order to perform the experimental poisoning, the pasture was cultivated in three dif­ferent paddocks: with nitrogen topdressing (urea; group 1), organic fertilizer (group 2) or without fertilizer (group 3; control). Nitrate accumulation in forage was evaluated by the diphenylamine test. After food fasting of 12 h, nine bovine were randomly allocated to one of the experimental groups and fed with fresh forage (ad libitum) from respective pad­dock. In different time points from beginning of pasture intake (0, 2, 4, 6 and 9 h) heart rate and respiratory frequency were assessed, as well as mucous membrane color and behavioral changes. Blood samples from jugular vein into vials with and without anticoagulant were collected. From blood samples, serum nitrite levels, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzyme activity were evaluated, as well as oxidative stress through the following param­eters: levels of nitrate/nitrite (NOx), thiobarbituric acid reactive substances (TBARS) and reactive oxygen species (ROS), beyond the antioxidant system by enzyme activity measurement of catalase (CAT) and superoxide dismutase (SOD). The diphenylamine test was positive to group 1 and 2, so that the pasture presented 3.16 mg/kg, 2.98 mg/kg and 1.67 mg/kg of nitrate for group 1, 2 and 3, respectively. In addition, cows from group 1 demonstrated increased (P < 0.05) nitrite levels in serum, compared to other groups, and greater heart rate after 9 h (P < 0.05). The AChE and BChE activity in group 1 showed significant increase (P < 0.05) at 4 and 6 h (AChE), and 4 and 9 h (BChE) compared to group 3. Also, NOx levels were lower at 6 and 9 h (P < 0.05) and at 9 h (P < 0.05) for animals of group 1 and 2, respectively, when compared to group 3. Furthermore, in the group 1 levels of ROS and TBARS were significantly higher (P < 0.05) after 2 and 4 h, and 6 and 9 h compared to other groups, respectively. The CAT activity increased significantly (P < 0.05) with 2 and 4 h of the experiment, but on the other hand, decreased at 6 and 9 h in group 1. Nevertheless, the animals from group 2 presented only a significant reduction in this enzyme activity at 9 h. Furthermore, SOD activity was reduced in animals of groups 1 (P < 0.05) at 4, 6 and 9 h, compared to other groups. Discussion: It was concluded that the nitrate and nitrite poisoning by pasture intake cultivated and fertilized with urea leads to increased levels of serum nitrite, as well as the cholinesterase activity and causes oxidative stress in cattle. It is conjectured that the cholinesterase activity and oxidative stress may assist in understanding the pathophysiology of changes caused by poisoning.Keywords: plant toxicology, poisoning, methemoglobin, cholinergic system, oxidative stress.

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