Factors affecting the efficiency of aerosolized salbutamol delivery via a metered dose inhaler and equine spacer device

Despite frequent use of metered dose inhalers (MDIs) and spacers in equine practice, limited information exists on the efficiency of aerosol delivery using such devices. We determined the particle size distribution within an MDI‐generated salbutamol aerosol delivered via an equine spacer using ‘best practice’ delivery technique and assessed the effect of variations in MDI use technique (shaking prior to each actuation, rapid repetitive actuations, and MDI angulation) on aerosol delivery efficiency. Under optimal conditions, only 53(±18) μg salbutamol per 100 μg actuation was delivered beyond the spacer. Although this aerosol had a high [89.6% (±2.4)] fine particle (<5 μm) fraction, and a low mass median aerodynamic diameter [2.52 (±0.29) μm], and particle size variability [geometric SD – 1.66 (±0.16) μm], within all particle size fractions, there was a high coefficient of variance (31–79%) of the percentage salbutamol delivered between experimental runs, thus impeding any effort to predict drug delivery to the patient during equine inhalation therapy. Despite observable trends and with the exception of minor statistically significant changes in the least abundant particle sizes, none of the deviations from a ‘best practice’ delivery technique significantly altered the relative salbutamol delivery beyond the spacer, a finding which has potential relevance with regard to maintaining user compliance.     

蒙古羊羊水源干细胞分离培养及其成骨分化研究

试验旨在建立羊水源干细胞系并对其诱导形成成骨细胞的潜能进行研究。在胎牛血清浓度为15%的条件下对羊水源干细胞进行建系,并检测其类胚体形成能力;检测不同代数细胞的干细胞标志基因Oct-4、SH2、SSEA-1、Nanog、HLA-ABC、CD117的表达情况;利用地塞米松、β-甘油磷酸钠、抗坏血酸等因子进行诱导。结果表明,羊水源干细胞在体外可以持续增殖,悬浮培养形成的类胚体表达三胚层相关标记基因,经诱导可形成成骨细胞。试验成功分离了蒙古羊的羊水源干细胞并建系,且其具有向成骨细胞分化的潜能。     

Chronic mesenteric volvulus in a dog

A chronic, partial mesenteric volvulus was found on laparotomy of an adult Bernese mountain dog with a 4-month history of intermittent vomiting, diarrhea, and weight loss. The dog had elevated cholestatic and hepatocellular leakage enzymes, increased bile acids, azotemia, isosthenuria, and a hypokalemic, hypochloremic, metabolic alkalosis. The dog recovered fully following reduction of the volvulus.     

猪繁殖与呼吸综合征病毒细胞受体研究进展

猪繁殖与呼吸综合征病毒(PRRSV)是引起猪繁殖与呼吸综合征(PRRS)的病原,对PRRSV细胞受体的研究将有助于揭示PRRSV的感染途径、复制过程、致病机理和疫病预防及控制等一系列问题,细胞受体的研究已经成为目前PRRSV研究中的重要领域。论文从硫酸乙酰肝素受体、唾液酸黏附素受体、CD163分子、波形蛋白等方面综述了PRRSV细胞受体研究进展。     

响应面法对金银花中绿原酸提取工艺的优化

为优化金银花中绿原酸提取率的最佳工艺条件,在单因素试验的基础上,应用Box-Behnken中心组合设计研究了乙醇质量分数、水浴时间、微波温度3个独立因子对金银花中绿原酸提取率的影响,再利用响应面分析法优化提取工艺条件。结果表明:绿原酸微波辅助提取最佳工艺条件为微波功率400W,微波温度58℃处理70 s,料液比1∶25,乙醇质量分数72%,60℃水浴加热51 min。经实际提取验证,绿原酸提取率为4.643 mg/g。     

20世纪60年代以来黄土高原小流域泥沙来源的方法与历史侵蚀过程研究进展

小流域作为黄土高原水土流失综合治理的基本单元,赋存了大量的泥沙侵蚀特征和侵蚀环境变化信息。它在减少黄土高原土壤侵蚀方面发挥着十分重要作用。概述了20世纪60年代以来黄土高原小流域泥沙来源和历史侵蚀过程方面的研究进展,小流域泥沙来源主要从传统方法、元素示踪法及REE稀土元素示踪法方面进行了分析,展望了未来小流域泥沙来源及泥沙侵蚀研究的发展,为小流域开展水土保持工作、对水土资源进行科学的评价和开展更深入的研究提供了重要参考。     

Analysis of veterinary drug residues in frog legs and other aquacultured species using liquid chromatography quadrupole time-of-flight mass spectrometry

A liquid chromatography quadrupole time-of-flight (Q-TOF) mass spectrometry method was developed to analyze veterinary drug residues in frog legs and other aquacultured species. Samples were extracted using a procedure based on a method developed for the analysis of fluoroquinolones (FQs) in fish. Briefly, the tissue was extracted with dilute acetic acid and acetonitrile with added sodium chloride. After centrifugation, the extracts were evaporated and reconstituted in mobile phase. A molecular weight cutoff filter was used to clean up the final extract. A set of target compounds, including trimethoprim, sulfamethoxazole, chloramphenicol, quinolones, and FQs, was used to validate the method. Screening of residues was accomplished by collecting TOF (MS1) data and comparing the accurate mass and retention times of compounds to a database containing information for veterinary drugs. An evaluation of the MS data in fortified frog legs indicated that the target compounds could be consistently detected at the level of concern. The linearity and recoveries from matrix were evaluated for these analytes to estimate the amount of residue present. MS/MS data were also generated from precursor ions, and the mass accuracy of the product ions for each compound was compared to theoretical values. When the method was used to analyze imported frog legs, many of these residues were found in the samples, often in combination and at relatively high concentrations (>10 ng/g). The data from these samples were also evaluated for nontarget analytes such as residue metabolites and other chemotherapeutics.     

浙江天童冬青属植物的种群结构及更新类型

为加强冬青属Ilex植物资源的保护和利用,采用标准样方法调查分析了浙江宁波天童4种冬青种群结构及更新类型。结果表明:1所调查群落共出现木本植物61种,除草本层外,林木层由下至上可分为灌木层和乔木层,其中在乔木层之上存在分别由小果冬青Ilex micrococca,马尾松Pinus massoniana,天童锐角槭Acer acutum构成的不连续的超高层。2所调查冬青属植物的年龄结构可分为4种类型:增长型(皱柄冬青Ilex kengii),稳定型(铁冬青Ilex rotunda),成熟型(冬青Ilex chinensis)和衰退型(小果冬青Ilex micrococca)。3冬青属植物总体生长良好,但有些种如小果冬青属于衰退型,无幼苗,无萌枝,种子更新困难,冬青幼苗难以通过环境筛导致幼树严重匮乏,需要采取适当人工育种以及栽培技术来加以繁殖保护,并对优良种质加以选育和利用。     

Comparison of varying doses and durations of ractopamine hydrochloride on late-finishing pig carcass characteristics and meat quality

The objective was to investigate the effect of various doses and durations of ractopamine hydrochloride (RAC) on pig HCW, cutting yields, and meat quality. Late-finishing pigs (approximately 93 kg) were allotted to 12 treatments 35 d before slaughter. Treatments consisted of negative control (NEG; 13.1% CP, 0.64 TID Lys), positive control (POS; 17.8% CP, 0.94 TID Lys), and 2 RAC doses (5 and 7.4 mg/kg) with 5 different feeding durations for each dose (7, 14, 21, 28, or 35 d). Pigs on ractopamine-duration diets were fed NEG until incorporation of RAC, and then the diet was switched to POS to comply with label requirements. A subset of 240 pigs was utilized to determine the effects of RAC on carcass cutting yields. This subset was selected by taking the 5 pigs closest to the average pen weight from 4 complete replicates. Differences in response to RAC between 5 and 7.4 mg/kg were not significant. Therefore, RAC dosages were pooled, resulting in an average dose of 6.2 mg/kg, which was then compared with NEG and POS diets. Ractopamine increased (P < 0.05) HCW by 2.5 and 2.3 kg compared with the NEG and POS diets, respectively. Hot carcass weight also increased linearly (P=0.003) as RAC duration increased. Indicators of carcass leanness increased with RAC compared with NEG. Estimated carcass lean percentage increased (P=0.010) 1 percentage unit from 54.79 to 55.79%, carcass cut yield increased (P<0.001) 1.23 percentage units from 50.61 to 51.84%, and (P=0.006) boneless lean cut yield increased 1.27 percentage units from 36.71 to 37.98%. Ractopamine decreased (P=0.002) subjective marbling scores 0.49 units from the NEG value of 3.0, but RAC did not differ (P=0.203) from POS. Subjective color values and shear force aging curves for RAC were not significantly different from NEG or POS. Overall, RAC had greater responses in carcass weight and cut yield than NEG, and had minimal effects on meat quality.     

Soil erosion modelling of burned and mulched soils following a Mediterranean forest wildfire

Soil erosion modelling applied to burned forests in different global regions can be unreliable because of a lack of verification data. Here, we evaluated the following three erosion models: (1) Water Erosion Prediction Project (WEPP), (2) Morgan-Morgan-Finney (MMF) and (3) Universal Soil Loss Equation-Modified (USLE-M). Using field plots that were either untreated or mulched with straw, this study involved observations of soil loss at the event scale at a burned pine forest in Central Eastern Spain. The erosion predictions of the three models were analysed for goodness-of-fit. Optimization of the MMF model with a new procedure to estimate the C-factor resulted in a satisfactory erosion prediction capacity in burned plots with or without the mulching treatment. The WEPP model underestimated erosion in the unburned areas and largely overestimated the soil loss in burned areas. The accuracy of soil loss estimation by the USLE-M model was also poor. Calibration of the curve numbers and C-factors did not improve the USLE-M model estimation. Therefore, we conclude that an optimized MMF model was the most accurate way to estimate soil loss and recommend this approach for in Mediterranean burned forests with or without postfire mulching. This study gives land managers insight about the choice of the most suitable model for erosion predictions in burned forests.