Metabolism of flupyrazofos in the isolated perfused rat liver

To investigate the hepatic metabolism of the new insecticide flupyrazofos [O,O-diethyl O-(1-phenyl-3-trifluoromethylpyrazol-5-yl) phosphorothioate], isolated rat liver was perfused with flupyrazofos under single-pass conditions. In outflow perfusate and bile, 1-phenyl-3-trifluoromethyl-5-hydroxyprazole (PTMHP), PTMHP-sulfate and PTMHP-glucuronide conjugates were identified as the metabolites of flupyrazofos. However, O,O-diethyl O-(1-phenyl-3-trifluoromethylpyrazol-5-yl) phosphate (flupyrazofos oxon) was not detected. A HPLC method with UV detection was used to investigate the hepatic disposition of flupyrazofos and its metabolite PTMHP. The concentrations of flupyrazofos, PTMHP and PTMHP conjugates in outflow perfusate reached steady-state levels within 20 min after commencing perfusion of 7.3 microM flupyrazofos. At steady state, the mean extraction ratio of flupyrazofos was 0.93 (+/- 0.01) and clearance was 26.1 (+/- 0.2) ml min-1 which nearly approached perfusate flow rate (28 ml min-1). PTMHP accounted for 55.7 (+/- 5.8)% of eliminated flupyrazofos and was recovered as unchanged PTMHP, PTMHP-sulfate and PTMHP-glucuronide in the bile as well as the outflow perfusate.     

CONTRAST-ENHANCED ULTRASONOGRAPHY IN NORMAL CANINE LIVER. EVALUATION OF IMAGING AND SAFETY PARAMETERS

Contrast-enhanced ultrasonography, a new imaging modality in veterinary medicine, can provide data on tissue perfusion. The objective of this study was to use the ultrasonographic contrast agent SonoVue to evaluate various transit time indices in the normal canine liver, to examine the effect of anesthesia on these parameters, and to evaluate the safety of this agent in dogs. The liver of 11 healthy dogs was studied by ultrasound during an intravenous bolus injection of SonoVue. Each dog underwent the examination twice, first with and later without the use of anesthesia. A time-intensity curve was generated from a selected region of interest within the liver from each scanning session. Ratios derived from peak enhancement, time to peak enhancement, up-slope and full-width half-maximum (FWHM) of the curve were calculated from the time-intensity curves, and are reported. There were no statistically significant differences (P > 0.05) in peak enhancement, up-slope and FWHM between dogs that were anesthetized and dogs that were not. Time to peak enhancement, however, was significantly shorter when the dogs were anesthetized than when they were nonanesthetized (P < 0.05). There were no biologically significant changes in clinical laboratory findings. This study indicates that contrast-enhanced ultrasound using SonoVue gives reproducible liver perfusion data, and appears to be a safe and well-tolerated agent for use in dogs. When considering normal values, the use of anesthetic drugs has to be considered.     

QUANTITATIVE CONTRAST ULTRASOUND ANALYSIS OF RENAL PERFUSION IN NORMAL DOGS

Eight normal dogs with no evidence of renal disease, weighing between 8 and 25 kg were imaged using contrast harmonic ultrasound after injection of a microbubble contrast medium. All dogs received three separate bolus injections of 0.05 ml of commercial contrast medium (Definity). Time/mean pixel value (MPV) curves were generated for selected regions in the cortex and medulla of the left kidney in each dog. Upslope, downslope, baseline, peak intensity, and time to peak were calculated for each zone. For a bolus injection, within the renal cortex (averaging all subjects) the upslope was 7.4 +/- 1.5 MPV/s, downslope was -0.4 +/- .2 MPV/s, baseline was 66.8 +/- 9.3 MPV, peak was 103.6 +/- 8.2 MPV, time to peak (from injection) was 12.8 +/- 5.3 s and from time of contrast medium reaching the kidney was 5.1 +/- 2.0 s. Within the renal medulla (averaging all subjects), upslope was 2.8 +/- 1.7 MPV/s, downslope was -0.3 +/- .2 MPV/s, baseline was 39.3 +/- 6.0 MPV, peak was 65.2 +/- 14.3 MPV, time to peak from injection was 20.9 +/- 6.4 s and from time of contrast reaching the kidney was 11.6 +/- 4.1 s. These baseline data may prove useful in the evaluation of dogs with diffuse disease or vascular compromise.     

犬低温体外循环手术及其灌注管理的试验研究

试验应用现代体外循环技术，实施完全心肺转流的低温体外循环，首次在我国兽医临床建立了２８只犬低温体外循环实验模型。探索适用于小动物心脏直视手术的体外循环手术操作、心脏停搏与复苏、体外循环灌注管理的技术方法。研究表明，选择右侧第４肋间进胸，从右心房施行前后腔静脉插管及升主动脉根部置供血管是简便易行的手术通路。采用部分晶体液与全血作预冲液，体外转流维持中度血液稀释（平均２３６８±３２７％），最低温度控制２６℃左右（平均２６１４±０７７℃），血流复温至３６℃左右（平均３５９７±０６８）开放升主动脉，转流中灌注压维持５０～９０ｍｍＨｇ（平均７２±１３ｍｍＨｇ），灌注流量８０～１００ｍＬ·ｋｇ－１·ｍｉｎ范围，是低温体外循环下开展犬心内直视手术成功的基本保障。采用冷晶与冷温血停搏液不同灌注。结果显示，冷温血停搏液联合灌注组心脏自动复跳率最高，并且复跳迅速，心搏有力，正性肌力药应用剂量小，复跳后辅助循环时间明显低于冷晶停搏液灌注组（Ｐ＜００５）。     

Expression of hypoxia-inducible factor 1 and neuroglobin in piglet cortex during deep hypothermic circulatory arrest

AIM: To observe the expression of hypoxia-inducible factor 1 (HIF-1) and neuroglobin (NGB) in piglet cortex during deep hypothermic circulatory arrest. METHODS: Wuzhishan piglets were randomly assigned to cardiopulmonary bypass group (CPB group), 40 min of circulatory arrest (CA) at 18 ℃ without cerebral perfusion (DHCA group) or with selective antegrade cerebral perfusion (SACP group). After 180 min of reperfusion, cortical tissue was harvested for determining HIF-1α and NGB expression by HE staining, Western blot and real-time PCR. RESULTS: Severer cerebral injury was observed in DHCA group than that in SACP group. After 180 min of reperfusion, HIF-1α protein and mRNA levels were significantly higher in DHCA group than those in CPB group (P<0.05). Accordingly, SACP animal had higher levels of HIF-1α protein and mRNA than those in DHCA group (P<0.05). Simultaneously, higher NGB protein and mRNA levels were found in DHCA group than those in CPB group after 180 min of reperfusion (P<0.05). The SACP animal had higher levels of NGB protein and mRNA than those in DHCA group (P<0.05). CONCLUSION: Up-regulation of HIF-1 and NGB are involved in the mechanism against cerebral injury resulting from DHCA in the cortex and possibly a part of cerebral protective effect of SACP.     

INTRAOPERATIVE CONTRAST‐ENHANCED ULTRASONOGRAPHY OF NORMAL CANINE JEJUNUM

Nine normal juvenile dogs were evaluated with direct jejunal contrast‐enhanced ultrasonography via midline celiotomy. Three different doses of ultrasound contrast medium (Definity^®) were injected through a peripheral venous catheter. Time‐intensity curves were used to calculate baseline, time to initial rise, inflow slope, time‐to‐peak, peak intensity (PI), and outflow slope for each administered dose. PI was directly proportional to dose. Outflow slope was similar for all patients, independent of dose. The most favorable images were acquired with a dose of 0.030 ml/kg given as a rapid intravenous manual bolus. The technique and normal jejunal perfusion pattern described herein may provide useful data for evaluation of intestinal vascular, inflammatory, and neoplastic disease in the dog.     

Morphology of the pig cornea in normal conditions and after incubation in a perfusion apparatus

The fine structure of the pig cornea in normal conditions and after being used in a perfusion apparatus, for 4 h, is described. Earlier reports on the normal morphology of the pig cornea were partly not confirmed. Thus the number of cell layers in the epithelium was found to be 19-23 (a basal cell layer, 4–5 polyhedral cell layers and 14–17 squamous cell layers) compared to earlier reported 6–9 layers.The mean thickness of normal and perfused corneas were 722 μm and 752 μm respectively. Normal corneas had a hydration level of 77.2 % and after perfusion 78.5 %. The normal morphology and morphological changes due to exposure to perfusion were studied by light and electron microscopy. The differences observed between normal and perfused corneas have to be considered limited, and restricted mainly to the anterior squamous epithelium and the endothelium.Taken together our results indicate that the corneas used in the apparatus still had functional integrity.     

Plant Growth Regulator Effects on Protein Content and Yield of Spring Barley and Wheat

Plant growth regulators (PGR) have potential to increase grain yield and may also alter grain protein levels of cereal crops. A 3-yr field experiment with spring barley ( Hordeum vulgare L.) and wheat ( Triticum aestivum L.) cultivars was conducted to determine whether ethephon treatment increased protein concentration, protein yield, and grain yield. A greenhouse experiment was also conducted to evaluate the response of barley grain protein concentration to gradual addition of ethephon (2.2 × 10^-3 mM) or chlormequat (5.8 × 10^-3 mM) solution after an thesis. Under field conditions, ethephon treatment increased barley and wheat grain protein concentrations by as much as 16 % but decreased grain yield so that protein yield increases were small or did not occur. For Laurier barley, total gram N content was increased by up to 20 % in one year of this study. However, over the 3 years, an inverse relation existed between grain protein and yield. Greenhouse data showed that i) the gradient in grain size and protein concentration among spikelets of a spike, which is established before anthesis, was not affected by either chlormequat or ethephon; and ii) chlormequat increased grain protein by 7 to 11 % whereas ethephon increased protein concentration by up to 13 % in one of the two experiments. Our data indicate that PGR can alter protein accumulation in the grain, and thus, the quality of bread wheat and feed barley crops can be increased m regions with a short crop-growing season. However, a portion of the increase in gram protein concentration is due to decreased starch deposition, which is associated with yield reductions. The greenhouse data confirmed that a portion of the increase in grain protein concentration due to PGR application is caused by increased protein accumulation in the barley grain.