无菌动物及其在微生物与宿主互作机制研究中的应用

无菌动物是指通过现代技术手段在其体内外的任何部位均检测不出细菌、真菌、放线菌、支原体、衣原体、螺旋体、立克次氏体、病毒、原生动物和寄生虫的动物。无菌动物因其不携带任何微生物,可转化为携带特定微生物的动物,同时因其免疫系统处于休眠状态,对微生物感染异常敏感,可建立多种悉生动物模型,用于特定微生物感染实验和致病机制研究。此外,无菌动物作为关键工具,是研究菌群与疾病关系的核心,在微生物与宿主健康、疾病和感染机制研究过程中,起着不可替代的作用。本文将对无菌动物及其在微生物与宿主互作机制研究中的应用进行简要综述。     

A-Level ‘Questions’ in Biology—The Nature of the Influence

The purpose of keeping animals in schools and the main problems encountered in their maintenance are summarised. Many teachers prefer animals which are kept typically in research laboratories over animals which can be collected from the student's environment. However, small animals of economic importance can combine some of the advantages of both of these groups of animals. Chickens, bees, plant pests and their natural enemies have been tried out in the Agriculture as Environmental Science Curriculum Project and can be used for observation and measurement as well as to stress the aspect of relevance to real life problems. In their maintenance, standard equipment and methods can often be used and help the teacher to solve some of the main problems of keeping animals.

Two curriculum units, on a fruit fly and on honey bees, are described. Reasons for a widespread negative image of rural studies are discussed, and positive, effective outcomes, reported in the evaluation of an environmental science course, are used to substantiate the advantages of keeping animals of economic importance in schools.     

The fourth EC report on the statistics of laboratory animal use: trends, recommendations and future prospects

At the beginning of 2005, the European Commission published its fourth report on the statistics of the number of animals used for experimental and other scientific purposes. A total of 10.7 million animals were used within the Member States of the European Union (EU) in 2002, an increase of almost a million animals since the 1999 report. France, Germany and the UK continue to be the largest users of animals for scientific purposes, and mice, rats, fish and birds remain the most commonly-used animals. For the first time, all 15 Member States used the standardised EU tables, as had been agreed in 1998. This has made it easier to identify areas on which Three Rs initiatives should be focused. Nevertheless, the reporting system still has a number of serious deficiencies. In particular, there are insufficient data on the numbers of animals that are kept or bred for research purposes, the numbers of transgenic animals, and the severity of procedures that are applied.     

Reduction of numbers of animals used in the quality control of biologicals

Laboratory animals are used for the quality control of vaccines. In particular, the potency testing of batches of inactivated vaccine requires large numbers of animals. The possibilities for reduction have been evaluated, and the results are summarised in this paper. Several approaches were studied, including the retrospective analysis of test data, with the objectives of determining the minimum number of animals required per vaccine dilution group, and evaluating the feasibility of a single-dose potency test. Other studies focused on the development of serology-based models and the use of genetically uniform animals. Based on the outcome of these studies, a substantial reduction in the number of animals used for the potency testing of toxoid vaccines has been achieved or will be achieved in the near future. As reduction alternatives can generally be explored in a relatively simpler and less time-consuming way than replacement alternatives, more emphasis should be placed on reduction strategies than at present.     

Predictability of Painful Stimulation Modulates the Somatosensory-Evoked Potential in the Rat

Somatosensory-evoked potentials (SEPs) are used in humans and animals to increase knowledge about nociception and pain. Since the SEP in humans increases when noxious stimuli are administered unpredictably, predictability potentially influences the SEP in animals as well. To assess the effect of predictability on the SEP in animals, classical fear conditioning was applied to compare SEPs between rats receiving SEP-evoking electrical stimuli either predictably or unpredictably. As in humans, the rat’s SEP increased when SEP-evoking stimuli were administered unpredictably. These data support the hypothesis that the predictability of noxious stimuli plays a distinctive role in the processing of these stimuli in animals. The influence of predictability should be considered when studying nociception and pain in animals. Additionally, this finding suggests that animals confronted with (un)predictable noxious stimuli can be used to investigate the mechanisms underlying the influence of predictability on central processing of noxious stimuli.     

Diagnosis of ecto- and endoparasites in laboratory rats and mice

Internal and external parasites remain a significant concern in laboratory rodent facilities, and many research facilities harbor some parasitized animals. Before embarking on an examination of animals for parasites, two things should be considered. One: what use will be made of the information collected, and two: which test is the most appropriate. Knowing that animals are parasitized may be something that the facility accepts, but there is often a need to treat animals and then to determine the efficacy of treatment. Parasites may be detected in animals through various techniques, including samples taken from live or euthanized animals. Historically, the tests with the greatest diagnostic sensitivity required euthanasia of the animal, although PCR has allowed high-sensitivity testing for several types of parasite. This article demonstrates procedures for the detection of endo- and ectoparasites in mice and rats. The same procedures are applicable to other rodents, although the species of parasites found will differ.     

Estimating the proportion of uncatchable animals in a population by double-sampling

Estimates of population size obtained by capture-recapture methods refer solely to the catchable portion of a population. Given a population containing marked animals, two closed-form maximum likelihood estimators of the proportion of uncatchable animals are presented. They are based on twice sampling the proportion of marked animals in the population: the first sample is drawn from catchable animals only, the second from mixed catchable and uncatchable animals. If the individuals in the first sample are not available to the second sample, both samples must be taken from a representative subpopulation of known size. The quantities required may be obtained during a standard capture-recapture session, provided the sampling methods meet the relevant assumptions; the ensuing estimate of population size can then be corrected for uncatchability. The technique is illustrated for eider ducks, using data from Coulson (1984, Ibis 126, 525-543).     

Animal Research Ethics in Africa: Is Tanzania Making Progress?

The significance of animals in research cannot be over‐emphasized. The use of animals for research and training in research centres, hospitals and schools is progressively increasing. Advances in biotechnology to improve animal productivity require animal research. Drugs being developed and new interventions or therapies being invented for cure and palliation of all sorts of animal diseases and conditions need to be tested in animals for their safety and efficacy at some stages of their development. Drugs and interventions for human use pass through a similar development process and must be tested pre‐clinically in laboratory animals before clinical trials in humans can be conducted. Therefore, animals are important players in research processes which directly and indirectly benefit animals and humans. However, questions remain as to whether these uses of animals consider the best interests of animals themselves. Various research and training institutions in Tanzania have established some guidelines on animal use, including establishing animal ethics committees. However, most institutions have not established oversight committees. In institutions where there may be guidelines and policies, there are no responsible committees or units to directly oversee if and how these guidelines and policies are enforced; thus, implementation becomes difficult or impossible. This paper endeavours to raise some issues associated with the responsible use of animals in research and training in Tanzania and highlights suggestions for improvement of deficiencies that exist in order to bridge the gap between what ought to be practised and what is practised.     

Inducible chemical defences in animals

Phenotypic plasticity is extremely widespread in the behaviour, morphology and life‐history of animals. However, inducible changes in the production of defensive chemicals are described mostly in plants and surprisingly little is known about similar plasticity in chemical defences of animals. Inducible chemical defences may be common in animals because many are known to produce toxins, the synthesis of toxins is likely to be costly, and there are a few known cases of animals adjusting their toxin production to changes in environmental conditions. We outline what is known about the occurrence of inducible chemical defences in animals and argue that there is immense potential for progress in this field. Possible directions include surveying diverse taxa to explore how general its occurrence may be and testing for selection acting on inducible chemical defences. Data on inducible chemical defences would provide insight into life‐history tradeoffs by enabling novel tests of how time‐costs and resource‐costs affect life‐history. If the synthesis of toxic compounds by animals proves accessible to manipulation, as it is in plants and fungi, this will open the way to refined estimates of the fitness costs of defence, ultimately providing a clearer picture of how plasticity evolves and is maintained in nature. Synthesis Inducible changes in the behaviour, morphology, and life‐history of animals are extremely widespread, but surprisingly little is known about similar changes in the production of defensive chemicals. We outline what is known about the occurrence of inducible chemical defences in animals and argue that there is immense potential for progress in this field. Possible directions include surveying diverse taxa to explore how general its occurrence may be and testing for selection acting on inducible chemical defences. Data on inducible chemical defences would provide insight into life‐history tradeoffs by enabling novel tests of how time‐costs and resource‐costs affect life‐history. If the synthesis of toxic compounds by animals proves accessible to manipulation, we will be able to estimate the fitness costs of defence more precisely, and ultimately provide a clearer picture of how plasticity evolves and is maintained in nature.     

Training for reduction in laboratory animal use

Reduction, refinement and replacement of laboratory animals wherever possible, are the guiding principles of the Federation of European Laboratory Animal Science Associations (FELASA) education guidelines. Of these, reduction is probably the least understood. Reduction and refinement are dependent upon each other. In the reduction "axis", there is a window of appropriate numbers of animals; too few and the experiment will lack power--too many and animals will be wasted. Reduction must be understood as the appropriate number of animals required for each experiment. The refinement "axis" is more straightforward. Better welfare is always desirable. Any factor can interfere with a study in two ways. If it changes the mean, this may not be serious, because it should do so in all groups. If it causes a change in variation, then this is far more troublesome, because this is bound to alter the appropriate number of animals for an experiment. Scientists are definitely concerned about the variation of the characters that they are working with. It is obvious that changes in variation may be study-specific, which makes the formulation of overall guidelines difficult. Indeed, instead of trying to assess the impact of housing and procedures on every possible character, it could be more productive to look at the effects of welfare indicators on variation, with the understanding that low variation here is likely to be reflected by low variation in most other characters, while aiming to achieve the most uniform welfare of the animals in the study.     

Environmental enrichment: room for reduction?

Environmental enrichment strategies are usually regarded as refinement. However, when the welfare of animals is enhanced through successful enrichment programmes, a reduction in the number of animals needed can be expected, because fewer animals might be lost during the course of experiments. Several examples of studies where enrichment can lead to reduction will be presented. They include the beneficial effects of nesting material for laboratory mice, the effects of husbandry procedures on controlling aggressive behaviour in male laboratory mice, and the effects of enrichment on variation in the results of experiments.     

Utilization of juvenile animal studies to determine the human effects and risks of environmental toxicants during postnatal developmental stages

BACKGROUND: Toxicology studies utilizing animals and in vitro cellular or tissue preparations have been used to study the toxic effects and mechanism of action of drugs and chemicals and to determine the effective and safe dose of drugs in humans and the risk of toxicity from chemical exposures. Testing in animals could be improved if animal dosing using the mg/kg basis was abandoned and drugs and chemicals were administered to compare the effects of pharmacokinetically and toxicokinetically equivalent serum levels in the animal model and human. Because alert physicians or epidemiology studies, not animal studies, have discovered most human teratogens and toxicities in children, animal studies play a minor role in discovering teratogens and agents that are deleterious to infants and children. In vitro studies play even a less important role, although they are helpful in describing the cellular or tissue effects of the drugs or chemicals and their mechanism of action. One cannot determine the magnitude of human risks from in vitro studies when they are the only source of toxicology data. METHODS: Toxicology studies on adult animals is carried out by pharmaceutical companies, chemical companies, the Food and Drug Administration (FDA), many laboratories at the National Institutes of Health, and scientific investigators in laboratories throughout the world. Although there is a vast amount of animal toxicology studies carried out on pregnant animals and adult animals, there is a paucity of animal studies utilizing newborn, infant, and juvenile animals. This deficiency is compounded by the fact that there are very few toxicology studies carried out in children. That is one reason why pregnant women and children are referred to as "therapeutic orphans." RESULTS: When animal studies are carried out with newborn and developing animals, the results demonstrate that generalizations are less applicable and less predictable than the toxicology studies in pregnant animals. Although many studies show that infants and developing animals may have difficulty in metabolizing drugs and are more vulnerable to the toxic effects of environmental chemicals, there are exceptions that indicate that infants and developing animals may be less vulnerable and more resilient to some drugs and chemicals. In other words, the generalization indicating that developing animals are always more sensitive to environmental toxicants is not valid. For animal toxicology studies to be useful, animal studies have to utilize modern concepts of pharmacokinetics and toxicokinetics, as well as "mechanism of action" (MOA) studies to determine whether animal data can be utilized for determining human risk. One example is the inability to determine carcinogenic risks in humans for some drugs and chemicals that produce tumors in rodents, When the oncogenesis is the result of peroxisome proliferation, a reaction that is of diminished importance in humans. CONCLUSIONS: Scientists can utilize animal studies to study the toxicokinetic and toxicodynamic aspects of drugs and environmental toxicants. But they have to be carried out with the most modern techniques and interpreted with the highest level of scholarship and objectivity. Threshold exposures, no-adverse-effect level (NOAEL) exposures, and toxic effects can be determined in animals, but have to be interpreted with caution when applying them to the human. Adult problems in growth, endocrine dysfunction, neurobehavioral abnormalities, and oncogenesis may be related to exposures to drugs, chemicals, and physical agents during development and may be fruitful areas for investigation. Maximum permissible exposures have to be based on data, not on generalizations that are applied to all drugs and chemicals. Epidemiology studies are still the best methodology for determining the human risk and the effects of environmental toxicants. Carrying out these focused studies in developing humans will be difficult. Animal studies may be our only alternative for answering many questions with regard to specific postnatal developmental vulnerabilities.     

Through the looking glass,and what we (don’t) find there

The conclusions drawn from mirror self-recognition studies, in which nonhuman animals are tested for whether they detect a mark on their bodies which can be observed only in the mirror, are based on several presuppositions. These include (1) that performance on the test is an indication of species wide rather than individual abilities, and (2) that all the animals which pass the test are demonstrating the presence of the same psychological ability. However, further details about the results of the test indicate that these presuppositions are false. Animals take the test as individuals, not as stand-ins for species, and members of different species rely on different cognitive mechanisms to pass the test. For nonhuman animals, passing the test seems to be a consequence of enculturation and practice.     

Heart and scaphognathite beat behaviour in laboratory-held Crangon crangon (L.)

Heart and scaphognathite beating activities of Crangon crangon (L.) have been monitored for several days under a fixed photoperiod regime. Freshly-captured animals, in particular, spend much of the light period buried in the substratum, and these periods are characterized by low heart rates and high scaphognathite beating rates. During the dark period, animals emerge from the sand. Swimming and walking excursions are most common during the first hours of the dark period, and such times are characterized by high heart rates and higher scaphognathite rates (both compared with daytime, buried rates). Periods of low activity, with the animals resting on the surface of the sand, extend over much of the remainder of the dark period, and at these times the animals had high heart rates but scaphognathite rates lower than those of buried animals. The increase in scaphognathite rates associated with the buried condition may be shown to be due to the gill ventilation system adopted by buried animals.     

Use of animals with unknown ancestries in scientifically managed breeding programs

Whether to incorporate animals with unknown ancestries as founders into scientifically managed captive breeding programs, can be a difficult decision. If the animals are offspring of known founders, their inclusion in the breeding program will result in an increased incidence of inbreeding in the captive population. If the animals are additional founders, excluding them from the breeding program will result in the loss of valuable genetic variation. In general, the practice in scientifically managed captive breeding programs is to exclude animals with unknown ancestries to avoid possible inbreeding. A method of estimating the cost of making an incorrect decision on whether to use animals of unknown ancestry as founders both in terms of lost genetic variation and increased inbreeding is presented. It was determined that the loss of genetic variation resulting from excluding founders is always greater than the loss of genetic variation caused by unequal founder line representation resulting from including related animals, as if they were founders. In addition, the increased rate of accumulation of inbreeding resulting from excluding founders will eventually overcome the initial inbreeding resulting from including related animals. However, in some cases, it will take a substantial number of generations for this to occur, and the benefits of possible lowered future expected inbreeding may never be realized. The decision concerning whether to use animals with unknown ancestry should, therefore, be based on the estimated relative costs of making an error, in terms of both lost genetic variation and expected future inbreeding, rather than on avoiding the immediate possibility of increased inbreeding alone. Two examples using studbook data are given to show how this method can be practically applied to the management of captive populations. © 1993 Wiley-Liss, Inc.     

Reinstatement of precipitated narcotic withdrawal hypothermia in the rat

Withdrawal hypothermia can be induced in rats by injection of naltrexone 72 h after subcutaneous implantation of a morphine pellet. At 45 days after implantation the same dose of naltrexone is without effect on body temperature and the animals are normally sensitive to the hypothermic effect of acute morphine administration. This acute administration of morphine re-sensitizes the animals to naltrexone so that administration of the antagonist again causes withdrawal hypothermia. These results are consistent with the view that narcotic dependence can be reinstated in previously dependent, but not naive, animals by acute administration of the narcotic.     

Managerial strategies in the captive propagation of endangered species

A captive propagation manager, committed to the welfare of captive populations of exotic animals, must often make decisions that are risky to individual animals. Innovative decisions that place animals at risk are essential to the progress of captive propagation. Such decisions must be grounded thoroughly on peer consultation, the scientific and zoo literature, and where possible on original applied research targeted specifically to the procedure in question. The management of two closely spaced births in a gorilla group is provided as an example.     

音乐治疗效应的动物实验研究

近年来国内外关于音乐治疗效应的动物实验研究认为：音乐能影响动物的情绪;音乐还对动物的免疫功能、学习及记忆能力、以及动物的神经系统结构和功能等均有一定影响。该领域的研究有利于深入探索音乐疗法的作用机理。     

Reduction strategies in animal research: a review of scientific approaches at the intra-experimental, supra-experimental and extra-experimental levels

When discussing animal use and considering alternatives to animals in biomedical research and testing, the number of animals required gets to the root of the matter on ethics and justification. In this paper, some reduction strategies are reviewed. Many articles and reports on reduction of animal use focus mostly on the experimental level, but other approaches are also possible. Reduction at the intraexperimental level probably offers the greatest scope for reduction, as the design and statistical analysis of individual experiments can often be improved. Supra-experimental reduction aims to reduce the number of animals by a change in the setting in which a series of experiments take place--for example, by improved education and training, reduction of breeding surpluses, critical analysis of test specifications, and re-use of animals. At the extra-experimental level, reduction is a spin-off of other developments, rather than the direct goal. Through improved research or production strategies, aimed at better quality, consistency and safety, reduction in the number of animals used can be substantial. A revised definition of reduction is proposed, which does not include the level of information needed, as in some cases reduction in the number of animals resulting in less information or data, is still acceptable.     

A primer on rodent identification methods

Identifying laboratory rodents as a group may be sufficient if all the animals are to receive the same treatment and/or manipulation and if individual variations in response are not to be recorded separately. However, it is frequently necessary to be able to differentiate between individual animals used in a study. Identification of individual animals may also be necessary to maintain health records and to properly manage colonies of laboratory animals in compliance with regulatory agencies and research protocol requirements.