Computer tomographic investigation of subcutaneous adipose tissue as an indicator of body composition

Background

Modern computer tomography (CT) equipment can be used to acquire whole-body data from large animals such as pigs in minutes or less. In some circumstances, computer assisted analysis of the resulting image data can identify and measure anatomical features. The thickness of subcutaneous adipose tissue at a specific site measured by ultrasound, is used in the pig industry to assess adiposity and inform management decisions that have an impact on reproduction, food conversion performance and sow longevity. The measurement site, called "P2", is used throughout the industry. We propose that CT can be used to measure subcutaneous adipose tissue thickness and identify novel measurement sites that can be used as predictors of general adiposity.

Methods

Growing pigs (N = 12), were each CT scanned on three occasions. From these data the total volume of adipose tissue was determined and expressed as a proportion of total volume (fat-index). A computer algorithm was used to determined 10,201 subcutaneous adipose thickness measurements in each pig for each scan. From these data, sites were selected where correlation with fat-index was optimal.

Results

Image analysis correctly identified the limits of the relevant tissues and automated measurements were successfully generated. Two sites on the animal were identified where there was optimal correlation with fat-index. The first of these was located 4 intercostal spaces cranial to the caudal extremity of the last rib, the other, a further 5 intercostal spaces cranially.

Conclusion

The approach to image analysis reported permits the creation of various maps showing adipose thickness or correlation of thickness with other variables by location on the surface of the pig. The method identified novel adipose thickness measurement positions that are superior (as predictors of adiposity) to the site which is in current use. A similar approach could be used in other situations to quantify potential links between subcutaneous adiposity and disease or production traits.     

胎儿期与成年期蒙古马骨骼肌肌纤维类型转化研究

为探索影响蒙古马胎儿期和成年期肌纤维类型差异机理.本研究选取3匹4月龄胎儿(两母一公)与3匹5岁健康成年母马身体4块分布全身、具有代表性的肌肉组织(长臂三头肌、夹肌、背最长肌、臀中肌)作为一个整体.胎儿期蒙古马肌纤维和成年期蒙古马肌纤维因存在差异各做为一组,试验进行3个生物学重复.首先对蒙古马骨骼肌肌肉样品进行免疫组化...     

实验室计量认证（复审）——规范化管理方法的探讨

以实验室规范化管理工作中积累的一些经验为基础,对实验室计量认证（复审）工作进行了认真的探讨,确定建立符合实验室资质认定评审准则的质量体系,按体系文件进行检测工作全程序质量控制,以期探索出一种操作性强并具有广泛普及意义的“实验室规范化管理方法”。     

A COMPARATIVE STUDY OF NUMERICAL CLASSIFICATION AND ORDINATION OF SOIL PROFILES IN A LOCALITY NEAR OXFORD

Data for 85 soil profiles, located at random within 17 physiographic units in a 1,000 km² area near Oxford, and each characterized by 37 properties, were analysed by two sets of multivariate techniques. Principal component analysis yielded two components accounting for 44 per cent of the total variation, and the distribution of the profiles along these components is plotted as a scatter diagram (ordination). Similarity analysis and hierarchical grouping (classification) were performed using three different similarity indices, two different standardization techniques, and three different sorting strategies. Before analysis the profiles were classified by two pedologists, independently using their judgement. For the Brown Earths there was moderately good agreement between the results of the two prior classifications and between them and those produced by the several numerical procedures. The degree of clustering was slight and much less than imagined prior to analysis. For the Gleys there was no evident clustering. Different numerical procedures gave different results, as also did the two prior classifications. Pedologists faced with difficult classificatory decisions cannot look to any hierarchical clustering strategy as arbiter, though they should get guidance from a principal component plot.     

Neoformed aragonite in clay soils on Keuper materials from east-central Spain

Fibrous radial aragonite nodules occur in a toposequence developed in the Triassic (Keuper) in a subhumid mediterranean climate (Soria, Spain). Neoformation in situ of the nodules in these soils is proposed, on micromorphological and physico-chemical grounds, such as their fragility, the inclusion of material from the groundmass, their occurrence along cracks and their high Mg: Ca ratio.     

甜菜总DNA不同提取方法的研究

采用CTAB法、SDS法、改进CTAB法和改进SDS法提取甜菜总DNA,并对提取得到的DNA进行质量鉴定和PCR扩增效果检测.结果表明：用改进的CTAB法提取的甜菜总DNA OD260/OD280在1.8左右,DNA纯度好,产率高,CTAB法和改进的SDS法产率次之,SDS法最低.同时对改进的CTAB法的提取条件进行优化,即用5.0 mL细胞提取液,0.8 mL无水乙醇, 0.6倍体积的异丙醇,可从1.0 g甜菜叶片中提取到高质量高纯度的DNA 764 μg/g.     

Long-term nutritional effects on the primary liver and kidney metabolism in rainbow trout, Oncorhynchus mykiss (Walbaum): adaptive response to a high-protein/non-carbohydrate diet and starvation of glucose 6-phosphate dehydrogenase activity

The adaptive response of the kinetics of glucose 6-phosphate dehydrogenase (G6PDH) was studied in trout liver and kidney after feeding (control or high-protein/non-carbohydrate diet) or starving for 30 days, as well as influences on growth and other nutritive parameters. Typical Michaelis-Menten kinetics were found for the hepatic catalysis of G6PDH under all conditions studied, without evidence of sigmoidicity. The administration of a high-protein/non-carbohydrate diet (61.0% protein, 7.9% lipids) produced no significant changes in specific activity or other kinetic parameters of the liver enzyme. This nutritional situation caused a significant daily increase in relative growth (20%) and feed efficiency (13.5%), as well as a 13% decrease in the protein-conversion efficiency, with respect to the control diet (46% protein, 8% lipids, 22% carbohydrates). On the other hand, long-term starvation (30 days), as a lipolytic condition, significantly decreased the activity and catalytic efficiency of hepatic G6PDH, by almost 45%, without significant changes in the K_m and activity-ratio values. These changes agree with a fall in the intracellular concentration of the enzyme as a consequence of a protein-repression process. The activity of the renal G6PDH was less than in the liver of control fish, and no variation in kinetics was found under the high-protein diet or starvation. This behaviour clearly demonstrates that the kidney pentose-phosphate pathway showed no adaptive response in relation to synthesis of fatty acids and other lipids.     

镉与微量元素在小麦吸收过程中的相互影响

为开发小麦生理阻控降Cd材料,以郑麦1354和郑麦1860为供试小麦品种,通过水培试验方法,研究了不同Zn（1~10μmol·L^-1）和Mn （1~10 μmol·L^-1）供应量对小麦生物量和Cd/Zn/Mn含量的影响,以及不同Cd （1~50 μmol·L^-1）胁迫水平对小麦生物量和Cd/Zn/Mn含量的影响。结果表明,5 μmol·L^-1 Zn和10 μmol·L^-1 Mn处理显著提高了两种小麦的生物量。Mn （1~10 μmol·L^-1）处理使郑麦1354和郑麦1860小麦地上部Cd含量分别降低了22.8%~29.4%和15.2%~17.5%,地下部Cd含量分别降低了25.7%~30.0%和28.6%~31.6%,Zn（1~10 μmol·L^-1）处理使郑麦1354和郑麦1860小麦地下部Cd含量分别降低了20.3%~34.3%和18.9%~43.0%,此外还使郑麦1354地上部的Cd含量降低了10.1%~13.1%。不同Cd胁迫（1~50 μmol·L^-1）均有提高小麦生物量的趋势。随着Cd胁迫水平的提高,两个品种地上部和地下部Cd含量均呈升高趋势,地下部Zn含量呈先增加后降低的趋势,Mn含量呈逐渐降低的趋势,表明在小麦吸收金属元素过程中,Cd与Mn存在竞争关系,而与Zn的关系则较为复杂,且其竞争程度因品种而异。研究表明,适度提高Mn和Zn供应能显著降低小麦植株Cd含量,因此Mn和Zn是实现小麦降Cd的有效生理阻控材料。