An appraisal of the in vivo role of phosphate as a modulator of urinary ammonium and titratable acid excretion in the acidotic rabbit

Previous studies have shown that the intravenous infusion of inorganic phosphate increased urinary ammonium excretion 8‐ to 10‐fold in the acidotic rabbit. This was considered to be a very important observation at the time and to be unique to the rabbit. While investigating this finding, we discovered that the formol titration procedure, used to measure urinary ammonium by this research group, is subject to interference by phosphate, casting doubt on the validity of the urinary ammonium excretion data reported by them in the literature. In order to re‐assess the importance of phosphate as a potential modulator of urinary ammonium excretion in the acidotic rabbit, renal net acid excretion studies were carried out in phosphate‐loaded acidotic animals. We observed that while urinary ammonium excretion increased significantly (p < 0.05) after 50 min of phosphate infusion, the maximum concentrations excreted were substantially less than previously reported in the literature. However, through its urinary buffering capacity, we observed that inorganic phosphate, via an experimentally induced phosphaturia, could substantially enhance titratable acid excretion. Contrary to earlier reports, we demonstrated that phosphate plays a relatively minor in vivo modulator role in enhancing renal net acid excretion through the vehicle of ammonium during acute metabolic acidosis in the hyperphosphataemic rabbit. The findings reported in this study constitute an important update on ammonia metabolism in the acidotic rabbit.     

Effect of increasing taurine and methionine supplementation on urinary taurine excretion in a model insectivore,the giant anteater (Myrmecophaga tridactyla)

The giant anteater (Mymercophaga tridactyla) is a highly specialized insectivore for which nutrient requirements are not clearly established, making diet formulation challenging for this species. Multiple clinical reports suggest anteaters have an obligate dietary taurine (TAU) requirement. Sulphur amino acid (SAA) metabolism in adult anteaters was evaluated using noninvasive methods to measure TAU synthesis potential from dietary methionine (MET) and a basal diet containing on a dry matter (DM) basis 1.7 mg TAU/kg DM and 6.9 g MET/kg DM. Urinary equilibrium times for TAU excretion were determined by feeding the basal diet with or without 1.5 g/kg DM supplemental TAU (crossover design; n = 4). Effects of supplemental dietary TAU (1.7, 2.0, 2.4, 2.7, 3.0, 3.3 g/kg DM) or MET (6.9, 9.0, 11.2 g/kg DM) on urinary TAU were evaluated (randomized block trials; n = 5 or 4 respectively). All urinary values (TAU, MET, unbound inorganic sulphate) were normalized to creatinine (CRT). Results indicate urinary TAU equilibrium in anteaters requires at least 2 weeks of feeding. Urinary ratio of TAU to CRT (TAU:CRT) increased as dietary TAU content increased from 1.7 to 3.0 g/kg DM, consistent with renal homoeostatic modulation of TAU excretion. Our data indicate that TAU needs were met by TAU in the basal diet or by de novo synthesis. Supplemental MET resulted in ~five‐ to eightfold increases in urinary TAU:CRT excretion, further supporting existence of mechanisms for TAU synthesis from dietary SAA in anteaters. Adult anteaters appear able to synthesize TAU when diets contain adequate SAA, but dietary TAU may be critical if protein intakes are low or of poor quality. This study may provide guidance on choice of domestic canids vs. felids as suitable physiologic models for improved nutrition in giant anteaters, and also outlines a noninvasive method for assessing TAU status/metabolism that may be useful across species.     

Measurement of urinary concentrations of the mycotoxins zearalenone and sterigmatocystin as biomarkers of exposure in mares

Mycotoxins may affect animal health, including reproduction. Little is known about the clinical relevance of exposure of horses to contaminated feed. This study aimed at (i) monitoring the levels of the mycotoxins zearalenone (ZEN), with its metabolites α‐ and β‐zearalenol (α‐ and β‐ZOL), and sterigmatocystin (STC) in urine samples from thoroughbred mares in Japan and (ii) relating these findings to the potential effects on reproductive efficacy of breeding mares. Sixty‐three urine samples of breeding mares from 59 breeding farms were used. Urine samples and reproductive records were collected from each mare when it was presented to the stallion station. Urinary concentrations of ZEN, α‐ and β‐ZOL, and STC were measured using liquid chromatography‐tandem mass spectrometry (LC‐MS/MS). ZEN, α‐ and β‐ZOL were measurable in the urine of all examined mares, indicating the prevalence of ZEN in equine feeds. In seven of the 63 samples, STC was also detected at levels ranging from 1.3 to 18.0 pg/mg creatinine. No significant correlation between the concentrations of mycotoxins and pregnancy status was observed. In conclusion, measurement of mycotoxins in urine samples is a useful non‐invasive method for monitoring the systemic exposure of mares to multiple mycotoxins.     

骆驼尿液对预防CCl_4诱导小鼠肝损伤的保护作用

试验旨在研究骆驼尿液对预防四氯化碳(CCl_4)诱导小鼠肝损伤的保护作用。将40只C57BL/6小鼠随机分为正常组,模型组,骆驼尿液低剂量组(170 mg/kg)、中剂量组(340 mg/kg)和高剂量组(500 mg/kg),3组骆驼尿液组灌胃相应剂量的骆驼尿液,正常组和模型组灌胃等量的生理盐水,每日灌胃1次,连续14 d;试验末期,除正常组外(橄榄油),各组小鼠腹腔注射20%CCl_4橄榄油混合溶液,建立小鼠急性肝损伤模型;12 h后摘眼球取血和采集肝脏样本,并记录肝脏重量,计算肝脏指数;测定小鼠血清相关指标,并进行肝脏组织病理切片检查。结果显示,与模型组比较,低、中、高剂量骆驼尿液组小鼠血清中谷丙转氨酶(ALT)、谷草转氨酶(AST)活性及总胆红素(TBIL)、碱性磷酸酶(ALP)、葡萄糖(GLU)含量较模型组均明显降低,白蛋白(ALB)、总蛋白(TP)含量升高,且高剂量组效果较好;而小鼠肝脏病理学切片观察显示,骆驼尿液组均有不同程度的改善,其中高剂量骆驼尿液组小鼠肝脏组织病理学损伤明显减轻,与正常组的肝脏组织形态接近。比较低、中、高3种浓度骆驼尿液处理发现,浓度越高治疗效果越好,说明骆驼尿液治疗效果具有剂量依赖性。综上所述,骆驼尿液对CCl_4诱导小鼠肝损伤具有一定的预防保护作用,且高剂量骆驼尿液组的效果较好。     

Histopathological nerve and skeletal muscle changes in rats subjected to persistent insulin-induced hypoglycemia

New insulin analogues with a longer duration of action and a flatter pharmacodynamic profile are developed to improve convenience and safety for diabetic patients. During the nonclinical development of such analogues, safety studies must be conducted in nondiabetic rats, which consequently are rendered chronically hypoglycemic. A rat comparator model using human insulin would be valuable, as it would enable differentiation between effects related to either persistent insulin-induced hypoglycemia (IIH) or a new analogue per se. Such a model could alleviate the need for an in-study-comparator and thereby reduce the number of animals used during development. Thus, the aims of the present study were i) to develop a preclinical animal model of persistent hypoglycemia in rats using human insulin infusion for four weeks and ii) to investigate histopathological changes in sciatic nerves and quadriceps femoris muscle tissue, as little is known about the response to persistent hypoglycemia in these tissues. Histopathologic changes in insulin-infused animals included axonal degeneration and myofibre degeneration. To our knowledge, this is the first study to show that persistent IIH provokes peripheral nerve and skeletal myofiber degeneration within the same animals. This suggests that the model can serve as a nonclinical comparator model during development of long-acting insulin analogues.     

饲料企业人力资源管理中的误区及对策

对饲料企业而言，人才逐渐成为企业发展的核心竞争力，但很多中小型饲料企业往往忽略了人力资源管理的重要性，所以本文从饲料企业人力资源管理的误区及对策入手，对饲料企业人力资源管理方面的现状及问题进行了分析，得出几条能提升饲料企业人力资源管理能力的对策建议。这些对策建议主要包括要加强企业管理层对人力资源管理的重视程度，建立专门的饲料企业人才库，提高专业技术人才在企业中的地位及建立完善的人力资源管理评价体系。这些举措对饲料企业人力资源管理有所助益，也是实现饲料企业长足发展的重要抓手。希望通过本文的研究，为饲料企业的人力资源管理提供一些思路和建议，使其能得到更加长远的进步和发展。 [关键词]饲料企业|人力资源管理|专业人才|管理误区     

人力资本对高校毕业生就业的影响——基于问卷数据的实证分析

基于上海、江苏高校毕业生的调研数据,采用Logistic回归,分析了人力资本各要素对高校毕业生就业实现和起薪的影响.结果发现对就业实现有影响的人力资本要素,并不一定能影响起薪,只有政治面貌、学习成绩和实习经历这三个人力资本要素同时对就业实现和起薪有积极影响.     

人力资本对新疆经济增长的影响分析及对策

运用柯布-道格拉斯生产函数和岭回归，定量分析了物质资本、人力资本、劳动力等要素对新疆经济增长的影响，并提出从提高人力资本存量，改善人力资本结构入手促进经济增长的对策建议.     

室内与家具设计中人体尺寸的选择和应用

在简要介绍人体尺寸的分类、百分位及人体尺寸数据表示的基础上,详细分析了人体尺寸在室内与家具设计中的选择与应用,以期对室内与家具设计人员在具体设计时有所帮助.