Comparison of research cost: man--primate animal--other animal models

The costs of research in human subjects are compared to those in primate animals and in other animal models on the basis of data available from a U.S. institution. The cost of experimentation in a chimpanzee is 3.59% of the per diem cost of clinical research in man. The cost for the dog is 37.1% of that of the chimpanzee, and the mouse costs 2.02% of the cost of the dog.     

The standardization–generalization dilemma: a way out

Recently, a debate has emerged on the use and necessity of standardization in experimental testing using animal subjects. The difficulties encountered when trying to reconcile standardization and generalization largely underlie this debate. The more specific the testing procedures are, the less one can generalize to more naturalistic situations, including to human clinical populations. If the goal of a study is to generalize to a larger population, there may be a higher risk attached to false‐positive than false‐negative results; thus the balance sways toward generalization. Heterogenization of housing conditions and of genetic makeup of experimental animals has been suggested as a possible method to increase the generalizability of results. It is important to remain cognizant, however, of situations in which false negatives can be counterproductive or even dangerous, such as when the goal is to elucidate a physiological mechanism, when expected effect sizes are small, in toxicological studies and in drug safety testing. In such cases, experiments based on standardization may provide more useful information. We pose that it is essential that the goal of the specific experiment conducted is clearly defined and that the decision to balance between standardization and generalization must be made based on the specific needs to meet the intended goal. In this light, we discuss a multi‐tiered approach to animal experimentation, in which standardization and generalizability are each given precedence during different phases of a project, depending upon the goal of the experiment.     

Living krill,zooplankton and experimental investigations: a discourse on the role of krill and their experimental study in marine ecology

Krill occupy critical positions in a many marine ecosystems and have been the subject of a number of concerted studies yet there are large areas of their biology that still remain a mystery. Most species of krill are open ocean animals, which makes direct observation and sampling difficult. Krill also exhibit a number of physiological and behavioural attributes which frustrate attempts to understand their life history. Krill are conceptually difficult to come to terms with; they are obviously different from larger marine organisms such as squid, fish, whales and fish yet they are also quite distinct from those animals classed as zooplankton such as copepods. Despite these differences they have most often been grouped with zooplankton and have been studied using techniques developed for animals which are orders of magnitude smaller than they. This mismatch has affected our view of their interactions with the physical world and also affects their perceived trophic interactions. Their size and mobility also interferes with our ability to sample them effectively and thus to develop our appreciation of their true role in the marine ecosystem. Understanding how intermediate-sized animals, such as krill, function in aquatic ecosystem is critical to better management of the marine environment.     

Alternatives to animal experimentation for hormonal compounds research

Alternatives to animal testing and the identification of reliable methods that may decrease the need for animals are currently the subject of intense investigation worldwide. Alternative testing procedures are particularly important for synthetic and natural chemicals that exert their biological actions through binding nuclear receptors, called nuclear receptors-interacting compounds (NR-ICs), for which research is increasingly emphasizing the limits of several models in the accurate estimation of the physiological consequences of exposure to these compounds. In particular, estrogen receptor interacting compounds (ER-ICs) have a great impact on human health from the therapeutic, nutritional, and toxicological point of view due to the highly permissive nature of the estrogen receptors towards a large number of natural and synthetic compounds. Similar to in vitro systems, recently generated animal models (e.g., animal models generated for the study of estrogen receptor ligands) may fulfill the 3R principles: refine, reduce, and replace. If used correctly, NR-regulated models, such as reporter mice, xenopus, or zebrafish, and models obtained by somatic gene transfer in reporter systems, combined with imaging technologies, may contribute to strongly decreasing the overall number of animals required for NR-IC testing and research. With these models, flexible and highly standardized parameters and reporter marker quantification can be obtained. Here, we highlight the need for the substitution of currently used testing models with more appropriate ones that can reproduce the features and reactivity of specific mammalian target tissue/organs. We consider the promotion of this advancement a research priority bearing scientific, economic, social, and ethical relevance.     

大鼠门静脉分支残端置管模型构建及细胞移植途径的评价*

摘要目的：大鼠肝部分切除模型被广泛的应用于肝脏疾病的研究,随着干细胞治疗肝损伤及护肝药物研究的发展,对大鼠肝损伤 模型也提出了很多新的要求。本实验拟在大鼠肝部分切除术的基础上改进以建立大鼠肝断面门静脉分支残端的静脉置管模型,并 进行细胞移植实验,对比分析新模型的优劣。方法：60 只F344 大鼠分为三组。A、B 组行行85 %肝切除术;C组行85 %肝切除术+ 肝断面门静脉分支残端置管术。术中B 组经门静脉注入4× 105个表达GFP（green fluorescence protein, GFP）的胎肝干细胞（fetal liver stem/progenitor cells, FLSPCs）。C组经留置导管注射入同等量的FLSPCs,A组注射同等剂量的培养液。72小时取血清,测定 肝功能ALT、AST,统计死亡率;取肝脏组织切片观察其修复情况。统计学采用方差分析和LSD-t 检验。结果：B、C组F344 大鼠 72 小时肝功指标（ALT、AST）均明显优于A 组;B 组、C 组肝脏组织学的病理损伤的恢复分别较A 组快。B、C组间肝功指标无统 计学意义。结论：经门静脉分支残端置管途径移植FLSPCs 效果等同于经门静脉穿刺途径,且该模型具有可反复、可选时、减少创 伤等优点。     

Liver injuries in frontal crash situations a coupled numerical—experimental approach

From clinical knowledge, it has been established that hepatic traumas frequently lead to lethal injuries. In frontal or lateral crash situations, these injuries can be induced by pure deceleration effects or blunt trauma due to belt or steering wheel impact. Concerning the liver under frontal decelerations, how could one investigate organ behaviour leading to the injury mechanisms? This work couples experimental organ decelerations measurements (with 19 tests on cadaver trunks) and finite element simulation, provides a first analysis of the liver behaviour within the abdomen. It shows the influence of the liver attachment system that leads to liver trauma and also torsion effects between the two lobes of the liver. Injury mechanisms were evaluated through the four phases of the liver kinematics under frontal impact: (1) postero-anterior translation, (2) compression and sagittal rotation, (3) rotation in the transverse plane and (4) relaxation.     

Home Gardens Sustain Crop Diversity and Improve Farm Resilience in Candelaria Loxicha,Oaxaca, Mexico

Home gardens are land use units embedded in a larger land use system, in this case in Candelaria Loxicha, Oaxaca, Mexico. Using a combination of qualitative and quantitative methods, we investigated how home gardens are integrated into local farming practices and how these influence biodiversity. Our findings suggest that home gardens harbour high levels of biodiversity, which are maintained and enriched by farmers’ practices, particularly plant and seed exchange. Plant diversity is higher in younger home gardens and in home gardens where owners actively exchange plant material with other people. Through plant exchange, seed storage, and the dispersion of seeds and plants in different land uses, farmers encourage plant diversity and consequently increase the resilience of their farming system in changing climatic, demographic and economic conditions. Both men and women participate in the establishment, care and management of home gardens, but they are responsible for different plants and home garden functions. For economic reasons, the inhabitants of Candelaria Loxicha are increasingly engaging in international migration. Migrants, upon their return bring new ideas and plants that might transform the rural landscape.