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排序方式: 共有459条查询结果,搜索用时 500 毫秒
21.
Rickets caused by excessive renal phosphate loss and apparent abnormal vitamin D metabolism in a cat
Henik RA Forrest LJ Friedman AL 《Journal of the American Veterinary Medical Association》1999,215(11):1644-9, 1620-1
Rickets was diagnosed in a 1-year-old cat with a history of weakness, osteopenia, and recurrent fractures. Processes causing rickets include vitamin D deficiency caused by inadequate, nutrition, lack of exposure to sunlight, defective metabolism of parent vitamin D to active metabolites, inherited vitamin D receptor defects, hypoparathyroidism, chronic renal failure, renal loss of phosphate, or malabsorptive states resulting from gastrointestinal or hepatic diseases. On the basis of analysis of serum 25-hydroxyvitamin D3 and 1,25-dihydroxyvitamin D2 and D3 concentrations, serum biochemical analysis, and urinary fractional clearance of electrolytes, the causes of rickets in our cat, were most compatible with a combination of excessive loss of phosphorus via the kidneys and deficient or abnormal hepatic 25-hydroxylation of vitamin D. Calcifediol treatment and twice daily administration of phosphate salts resulted in clinical improvement and increases in mineralization of the skeleton, as evidenced on radiographic evaluation. 相似文献
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Sprott LR Harris MD Forrest DW Young J Zhang HM Oyarzo JN Bellin ME Ax RL 《Journal of animal science》2000,78(4):795-798
In this study, semen samples from 25 bulls that had passed a breeding soundness evaluation were analyzed for the presence or absence of a 31-kDa protein, known as fertility-associated antigen (FAA), on spermatozoal membranes. Eighteen bulls had FAA on sperm (FAA-positive) and seven were devoid of FAA on sperm (FAA-negative). A single ejaculate from each bull was extended and frozen with 25 to 30 x 10(6) sperm in .5-mL straws. Crossbred replacement heifers (n = 865) were estrus-synchronized and artificially inseminated either at timed AI or 12 h after they were detected in estrus. Mature cows (n = 285) were inseminated 12 h after they were detected in estrus during a 45-d AI period. Pregnancy rates (pooled) to first AI service for females (n = 764) inseminated with FAA-positive sperm were 65.6% and were 49.7% for females (n = 386) inseminated with FAA-negative sperm (P < .005). Among the estrus-synchronized replacement heifers, pregnancy rates to synchronized AI service for heifers (n = 550) inseminated with FAA-positive sperm were 62% and were 45.7% for heifers (n = 315) inseminated with FAA-negative sperm (P < .005). These data indicate that pregnancy rates to first AI service at spontaneous and synchronized estrus are higher when using semen from bulls with detectable FAA on spermatozoal membranes compared to semen from bulls devoid of FAA on membranes. Fertility-associated antigen is an important determinant for fertility potential of sperm from bulls to be used in AI breeding programs. 相似文献
24.
采用免疫组织化学方法对不同日龄的长爪沙鼠颌下腺IgA的定位分布进行了研究。结果表明,长爪沙鼠的颌下腺由导管部和分泌部构成,分泌部主要由浆液腺构成,导管部包括闰管、纹管、颗粒曲管和小叶间导管等。DAB显色结果表明,IgA阳性细胞主要分布于浆液性腺泡、闰管、纹管、颗粒曲管和小叶间导管,并可分布于腺泡和腺管间结缔组织,IgA阳性产物的分布具有不均一性,无明显随年龄变化的规律性。阳性产物分布于胞质中,胞核呈阴性,对照组阴性。提示从浆细胞产生或循环而来的IgA先经结缔组织进入颌下腺组织,进而定位分布于浆液腺泡和各级导管,导管部有较多的IgA分布。 相似文献
25.
Forrest W. Nutter Jr Paul D. Esker Rosalee A. Coelho Netto 《European journal of plant pathology / European Foundation for Plant Pathology》2006,115(1):95-103
New concepts in phytopathometry continue to emerge, such as the evolution of the concept of pathogen intensity versus the
well-established concept of disease intensity. The concept of pathogen severity, defined as the quantitative measurement of
the amount of pathogen per sampling unit has also emerged in response to the now commonplace development of quantitative molecular
detection tools. Although the concept of disease severity, i.e., the amount of disease per sampling unit, is a well-established
concept, the accuracy and precision of visual estimates of disease severity is often questioned. This article will review
disease assessment concepts, as well as the methods and assessment aides currently available to improve the accuracy and precision
of visually-based disease severity data. The accuracy and precision of visual disease severity assessments can be improved
by quantitatively measuring and comparing the accuracy and precision of rates and/or assessment methods using linear regression,
by using computer-based disease assessment training programmes, and by developing and using diagrammatic keys (standard area
diagrams). 相似文献
26.
27.
土壤活性有机碳能够准确反映土壤有效性,表征土壤质量变化,是探索可持续草地管理措施的关键指标之一。以内蒙古贝加尔针茅草原为研究对象,采用围封、放牧和刈割野外控制试验,探讨不同利用方式对土壤有机碳(SOC)和活性有机碳的影响,发现不同利用方式下土壤SOC含量表现为围封>刈割>放牧,其中围封区和刈割区土壤SOC含量显著大于放牧区,围封区与刈割区土壤SOC含量差异不显著,在土壤活性有机碳中土壤可溶性有机碳(DOC)含量表现为放牧>围封>刈割。土壤微生物量碳(MBC)和土壤易氧化有机碳(ROC)含量均表现为围封>刈割>放牧,围封区与刈割区土壤MBC和土壤ROC平均含量差异不显著,且均显著大于放牧区。土壤MBC、ROC和SOC之间呈极显著相关性(P<0.01)。土壤ROC和土壤MBC与土壤全氮和土壤全磷呈极显著相关性(P<0.01)。围封与刈割有利于土壤SOC、MBC、ROC的提升,放牧对土壤DOC有一定累积作用。围封和刈割增强了土壤SOC的稳定性,活性有机碳与土壤有机碳和土壤理化性质密切相关,能够敏感地反映土壤有机碳的变化。 相似文献
28.
基于EDA技术的自动立木整枝机无线遥控发射系统 总被引:4,自引:0,他引:4
立木整枝是优质工业用材林定向抚育的重要环节,采用自动立木整枝机是实现高效、高质量和安全可靠整枝的有效途径。本文综合运用电子电路设计及优化技术、无线遥控及通信编解码技术,创造性地研制了基于CPLD的无线数字编码抗干扰自动立木整枝机无线遥控发射系统,通过优化CPLD内部逻辑电路有效消除了逻辑竞争冒险、降低了噪声干扰,确保了系统逻辑设计的正确性。该系统具有可靠、节能、抗干扰、工作效率高等优点。本研究成果及方法为推进其他林业机械的自动化与智能化进程提供了一种有效的新思路。 相似文献
29.
GM Alvarez SA Morado MP Soto GC Dalvit PD Cetica 《Reproduction in domestic animals》2015,50(2):200-205
The aim of this study was to examine the effect of varying intracellular reactive oxygen species (ROS) levels during oocyte in vitro maturation with enzymatic ROS production systems (xanthine + xanthine oxidase or xanthine + xanthine oxidase + catalase), scavenger systems (catalase or superoxide dismutase + catalase) or cysteine on porcine oocyte maturation. Oocyte ROS levels showed an increase when H2O2 or O2?‐ production systems were added to the culture medium (p < 0.05). On the other hand, the presence of ROS scavengers in the maturation medium did not modify oocyte ROS levels compared with the control after 48 h of maturation, but the addition of cysteine induced a decrease in oocyte ROS levels (p < 0.05). The ROS production systems used in this work did not modified the percentage of oocyte nuclear maturation, but increased the decondensation of sperm head (p < 0.05) and decreased the pronuclear formation (p < 0.05). In turn, the addition of O2?‐ and H2O2 scavenging systems during in vitro maturation did not modify the percentage of oocytes reaching metaphase II nor the oocytes with decondensed sperm head or pronuclei after fertilization. However, both parameters increased in the presence of cysteine (p < 0.05). The exogenous generation of O2?‐ and H2O2 during oocyte in vitro maturation would not affect nuclear maturation or later sperm penetration, but most of the spermatozoa cannot progress to form the pronuclei after fusion with the oocyte. The decrease in endogenous ROS levels by the addition of cysteine would improve pronuclear formation after sperm penetration. 相似文献
30.
Da Chuan Piao Tao Wang Jae Sung Lee Renato SA Vega Sang Ki Kang Yun Jaie Choi Hong Gu Lee 《畜牧与生物技术杂志(英文版)》2015,6(1)