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Using pig biliary system, in vivo propagation of Enterocytozoon bieneusi, an AIDS-related zoonotic pathogen.

A microsporidian parasite Enterocytozoon bieneusi is the most common microorganism recognized in AIDS patients, and slow scientific progress is attributed to our inability to propagate the parasite. We report upon the development of a system of propagation using the pig biliary system. The parasite spores were continuously detected in the bile samples post onset of spore shedding in the gall bladder, which suggests that this organism maintain persistent infection in the biliary system and that the hepatobiliary tree may represent a reservoir of infection. In conclusion the biliary tree is an adequate niche for the propagation of E. bieneusi. This work has also resulted in the development of a procedure of ultrasound-guided cholecystocentesis for aspirating biles. This is a simple and non-surgical procedure, and creates no signs of clinical complications in the livers and the gall bladders after dozens of separate attempts. Thus, this is a very useful and safe technique for the aspiration of bile from live animals.

AIDS-Related Opportunistic Infections↗

[Systematic modelling in nutrition].

Live organisms can be considered as open complex systems in a steady state through which passes a flow of matter which undergoes a series of transformations which constitutes the nutritional process. The systemic approach and modelling procedure can be applied to nutrition as it can to other scientific areas, although examples of this particular application are few. This review describes the complexity of components in nutritional systems and presents a means of simplifying this. A section is given over to a comparative study of the main types of models (empirical vs mechanistic, static vs dynamic) which can be applied to nutrition. The other topics covered concern the modelling of the regulating systems in nutrition (homeostasis, homeorhesis), model validation and comments on application models and research.

Animal Nutritional Physiological Phenomena↗

[A complex large scale cockroach control model. I. Organization].

The modern human living conditions are said to prospect to new ways of spreading cockroaches. Thus, the control measures applied nowadays are practically ineffective. Accordingly, the following control strategy is recommended, consisting in of: 1. The time range needed for performing the control procedures is to be determined; 2. The competent leading organs of the Civil Service and those of the national economy responsible for a correct performance of control procedures should be determined; 3. The involvement in the control procedures of people working in establishments harbouring cockroaches should be guaranteed; 4. It regulates the introduction of control measures and procedures. Such a control system based on an experience gained in the district of Potsdam (GDR) will be proposed as a "complex largespace control of cockroaches". The conception of a pattern of the modern control methods of cockroaches is based on principles of the scientific labour organization.

Animals↗

Restoring function after spinal cord injury.

BACKGROUND: By affecting young people during the most productive period of their lives, spinal cord injury is a devastating problem for modern society. A decade ago, treating SCI seemed frustrating and hopeless because of the tremendous morbidity and mortality, life-shattering impact, and limited therapeutic options associated with the condition. Today, however, an understanding of the underlying pathophysiological mechanisms, the development of neuroprotective interventions, and progress toward regenerative interventions are increasing hope for functional restoration. REVIEW SUMMARY: This study addresses the present understanding of SCI, including the etiology, pathophysiology, treatment, and scientific advances. The discussion of treatment options includes a critical review of high-dose methylprednisolone and GM-1 ganglioside therapy. The concept that limited rebuilding can provide a disproportionate improvement in quality of life is emphasized throughout. CONCLUSIONS: New surgical procedures, pharmacologic treatments, and functional neuromuscular stimulation methods have evolved over the last decades that can improve functional outcomes after spinal cord injury, but limiting secondary injury remains the primary goal. Tissue replacement strategies, including the use of embryonic stem cells, become an important tool and can restore function in animal models. Controlled clinical trials are now required to confirm these observations. The ultimate goal is to harness the body's own potential to replace lost central nervous system cells by activation of endogenous progenitor cell repair mechanisms.

Humans↗

The 3Rs and animal welfare - conflict or the way forward?

The animal experiment is central to the 3R concept. In European law, animal experiments are classed according to their aims. In the German animal protection law, they are classed, e.g. as interventions and treatments for experimental purposes, for further education and training, or for the production, preparation, storage or multiplication of substances, products or organisms and for the fulfillment of legal requirements, and are thus regulated with varying strictness. In contrast, in Switzerland all such measures performed on live animals underlie the same approval requirements. For animal welfarists, the term "animal experiment" includes every intervention and every treatment which is associated with pain, fear and/or suffering and does not directly benefit the respective animal. In the animal experiment, the animal concerned usually suffers as a human would, independent of the experimental goal. Expecting an animal to suffer a treatment one would not want to undergo oneself cannot be in accord with an ethic of respect for fellow creatures. Animal welfarists aim to save animals such suffering. Consequently, they demand the immediate abolition of all animal experiments. From the perspective of those who allow animal experiments to be performed or who perform them themselves, the goal of the experiment is more important than the animal. Therefore, the following question is central to 3R research: "Can I reach my goal while causing the animal less suffering, using fewer animals or without using animals at all?" The starting point is that the ethical responsibility for man is valued higher than that for the animal. The aim is to protect humans from harm caused by substances and products or from unwanted side effects of medication, to understand diseases and to search for a cure or alleviation of these. When a scientist reaches his goals without using animals, the demand of animal welfarists to abolish the animal experiment is fulfilled. These aspects do of course not encompass all the differences and agreements in the positions of animal welfarists and those who support animal experiments. It is not without reason that the discussion around animal experiments is multifaceted and continues to be held intensely from all positions. The classic pattern of a discussion entails that the one side collects the arguments which illustrate that animal experiments lead to wrong results, cannot be transferred and finally stand more against than for the good of mankind. The latter statement is valid, because the wrong methods benefit from investment, thus preventing or hindering new, better research and application of knowledge. The other side uses, among others, the argument that the person performing the experiment knows the limits of the test procedure and can deal with them accordingly. For further defense of current and future animal experiments, scientists like to present their organ transplant patients, i.e. those who can only lead a life worth living thanks to continuous medication, and admonish that patients with Alzheimer's or Parkinson's disease or with cancer put their last hope into new medical insights which can only be gained with animal experiments. Animal welfarists argue against this, that the motivation for animal experiments does not always lie in the ethical responsibility for mankind, but also in pure gain of knowledge, titles and money. After all, they also claim that they are protecting man, animal and environment from diseases and want to help them. It is not about saving animals at any price, even including human life, as is commonly brought against them. But they are also not prepared to accept that without real necessity or at any hint of a dilemma, the decision always falls immediately against the animal. The animal experiment may no longer be the method of choice, both for ethical and also for scientific reasons. What does all of this have to do with 3R research? It is a fact that animal experiments are still the method of choice, the "gold standard". The official German statistics on animal experiments in 2001 (Governmental animal protection report, 2002) counts a total of 2.13 mill. experimental animals, with a tendency towards a further increase. The increase is ascribed to animal experiments especially in basic research, counting 926,294 animals. The other more than a million animals were used for research and development of products and equipment for human, dental or veterinary medicine (509,101), the production or quality control of products or equipment for human, dental or veterinary medicine (289,273), toxicological investigations or other safety tests (189,996), the diagnosis of diseases (26,508), education and training (39,625) and other purposes (145,764). Before this background, all activities which lead away from animal experiments or reduce the suffering caused in the remaining experimental animals must be judged as positive developments. 3R research leads to a reduction of animal experiments and animal suffering. At the same time, the earnest consideration of the 3Rs also leads to a critical and specific discussion of the animal experiment in question.

Animal Experimentation↗

Application of stem cells for cardiovascular grafts tissue engineering.

Congenital and acquired heart diseases are leading causes of morbidity and mortality world-wide. Currently, the synthetic materials or bioprosthetic replacement devices for cardiovascular surgery are imperfect and subject patients to one or more ongoing risks including thrombosis, limited durability and need for reoperations due to lack of growth in children and young adults. Suitable replacement grafts should have appropriate characteristics, including resistance to infection, low immunogenicity, good biocompatability and thromboresistance, with appropriate mechanical and physiological properties. Tissue engineering is a new scientific field aiming at fabrication of living, autologous grafts having structure or function properties that can be used to restore, maintain or improve tissue function. The use of autologous stem cells in cardiovascular tissue engineering is quite promising due to their capacity of self-renewal, high proliferation, and differentiation into specialized progeny. Progress has been made in engineering the various components of the cardiovascular system, including myocardial constructs, heart valves, and vascular patches or conduits with autologous stem cells. This paper will review the current achievements in stem cell-based cardiovascular grafts tissue engineering, with an emphasis on its clinical or possible clinical use in cardiovascular surgery.

Animals↗

Biologicals: test procedures available to assess components and products, with limitations.

Contamination with a pathogen, residual live organisms in inactivated products, and a lack of safety of live products may be considered to constitute the greatest risks associated with the use and the international movement of biological products. Although tests are conducted to monitor the risks, the limitations of such tests must be recognised and steps should always be taken to minimise and, as far as possible, avoid the risk. Tests must be suitably sensitive and specific for their function, but they must also be practical and reproducible. Studies on the sensitivity of tests provide a measure of their limitations. The author describes points to consider for the assessment of the suitability of different test methods. Emphasis is placed on tests for parameters associated with risk, such as extraneous agent testing. Examples of such analyses are discussed. There is a need for an exchange of information and a scientific debate on such issues if international acceptance of test methods and harmonization of requirements are to be achieved.

Animals↗

Acoustic and ultrasonic tissue characterization--assessment of osteoporosis.

Osteoporosis, often termed the 'silent epidemic', has been defined as 'a decrease in bone mass and architectural deterioration of bone tissue, leading to enhanced bone fragility and consequent increase in fracture risk'. In the United Kingdom alone, the annual health costs are in excess of 750 million Pounds, with 60,000 patients suffering a hip fracture each year. A quarter of these will die within 12 months of their fracture, half of the remainder will never regain independent living. The established procedure for assessing the risk of osteoporotic fracture is via bone mineral density (BMD) assessment using dual-energy X-ray absorptiometry (DXA). However, DXA is an expensive technique and is not widely available. Within the past 15 years, ultrasound assessment of bone has rapidly advanced in scientific understanding, technical development and clinical utility. Measurements of cancellous bone (particularly at the calcaneus) are generally performed in preference to those of cortical bone (tibial cortex). There are currently 15 commercial systems available and over 3500 systems are in use world-wide. The low cost and portability offered by ultrasound systems should enable an integrated community-based screening programme to be established in the near future. Ultrasound measurements of bone are generally obtained using transmission rather than pulse-echo techniques owing to its highly attenuating nature. Ultrasound velocity and attenuation measurements are utilized. For velocity, there are well-defined fundamental relationships describing the dependence upon the elasticity and density of bone.

Absorptiometry, Photon↗

From DNA to NDA--the impact of recombinant DNA technology on new drug development.

Man's long-standing efforts to alter living things through genetic manipulation have become reality. Recent advances in recombinant DNA technology have the potential to alter the drug-development process profoundly. The pharmaceutical industry has had to adjust its research efforts and develop new state-of-the-art laboratories. In addition to the standard biological and in vivo assays, many new tests are required, e.g., amino acid sequencing, high-pressure liquid chromatography, and radioimmunoassays. Academic researchers have played a vital role in developing the new biotechnology, supplying most of the basic scientific knowledge and the initial supply of the scientific work force. The recent shifting of support for scientific training from the government to the pharmaceutical industry has resulted in unprecedented academe-industry relationships. Universities now stand to profit significantly from patent rights resulting from biotechnology research efforts. While the advances in biotechnology have had considerable impact on the pharmaceutical industry and academia, they have thus far had only a minor impact on the regulatory process. To date, the preferred regulatory path appears to be modification of existing procedures through the issuance of guidelines, which can be updated as knowledge increases.

Academies and Institutes↗

Studying variations in the PCDD/PCDF profile across various food products using multivariate statistical analysis.

Polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) are widely recognized by the scientific community as persistent organic pollutants due to their toxicity and adverse effects on wildlife and human health. The actual regulation dedicated to the monitoring of dioxins in food is based on the measurement of 17 congener concentrations. The final result is reported as a toxic equivalent value that takes into account the relative toxicity of each congener. This procedure can minimize the qualitative information available from the abundances of each PCDD/PCDF congener: the characteristic contamination profile of the sample. Multivariate statistical techniques, such as principal component analysis (PCA) or linear discriminant analysis (LDA), represent an interesting way to investigate this qualitative information. Nevertheless, they have only been applied to the analysis of contamination data from food products and biological matrices infrequently. The objective of the present study was to analyze a large data set from dioxin analyses performed on various food products of animal origin. The results demonstrate the existence of differences in congener-specific patterns between the analyzed samples. Variability was first demonstrated in terms of the food type (fish, meat, milk, fatty products). Then a variability was observed that was related to the specific animal species for meat and milk samples (bovine, ovine, porcine, caprine and poultry). Some practical applications of these results are discussed. The origin(s) of the observed differences, as well as their significance, now remain to be investigated, both in terms of environmental factors and transfer through living organisms. A better knowledge of the relation between a contamination profile and its specific source and/or food product should be of great interest to scientists working in the fields of contaminant analysis, toxicology and metabolism, as well as to regulatory bodies and risk assessors in charge of final decisions regarding the eventual hazards associated with theses substances.

Animals↗

[Epizootiological prerequisites and results of use of live vaccines].

Immunobiological action holds a firm position in veterinary legislation of the GDR with regard to the prevention and control of zoonoses, parasitoses, and other risk factors. Here are some of the conditions which have to be satisfied for systematic and purpose-oriented application of live vaccines: (a) Stringent procedures and rules for testing and acceptance of pharmaceutical preparations; (b) Availability of scientifically founded concepts of application which have to be submitted for translation from research to production and for acceptance and which require for use under practice conditions prior permission of veterinary authorities or other legal consent; (c) Knowledge of both prevalence and incidence of the epidemic diseases for which live vaccines are to be used in prophylaxis and after-care; (d) Verification of good success of live vaccines (decline and regression of diseases or reduction of economic loss) and identification of factors with detrimental impact upon effectiveness; (e) High organisational efficiency of public veterinary services and availability of comprehensive networks for diagnosis to ensure effectiveness and harmlessness of all strategical and tactical measures taken. In the GDR, the above demands are met. The epizootiological situation has clearly improved. Appropriate and meaningful use of live vaccines is not contradictory to culling concepts. Whenever the use of live vaccines appears to be impermissible for epizootiological and other reasons, the possible economic damage likely to result from non-use should be included in the discussion. The latter would be of particular importance in the context of industralised livestock farming with high concentration and specialisation.

Animal Diseases↗

Can high-frequency sound affect gas-bubble dynamics? A study in the intact prawn Palaemon elegans.

Underwater sound beacons (pingers) are employed in professional and scientific diving for location and navigation. Previous studies have demonstrated that exposure to acoustic fields may lead to the emergence of bubbles and cavities in tissues by rectified diffusion. However, this issue was studied mainly in vitro in various gels and isolated tissues. In the present study, we used the intact prawn Palaemon elegans, whose transparent shell makes it possible to conduct continuous microscopic observation of gas-bubble dynamics in the intact living prawn, to study the effect of high-frequency sound. In a crossover designed experiment, prawns were exposed to hyperbaric pressure of 203 kPa for 10 min, followed by decompression at 40 m/min (control). This procedure was carried out in the study group during transmission of a 37-kHz, 0.25-W, 10-ms pulse width, 1 pulse/s pulse interval. A significant increase was found in the mean volume of bubbles present for a longer period of time, in a higher percentage of the high-frequency sound-exposed prawns. We suggest that this sound exposure causes more gaseous micronuclei to grow into bubbles, and more of the dissolved gas to shift into the gas phase.

Animals↗

Chilean legislation for the control of diseases of aquatic species.

The Political Constitution of Chile establishes the right of the people to live in an environment which is free from contamination. The State has a duty to uphold this right and to preserve nature. With the aim of reconciling this constitutional guarantee with the pursuit of profitable economic activities, the concept of 'sustainable development' has been promoted. This mechanism makes it possible to use natural resources and the environment in a rational, effective and efficient manner both at present and in the future, and led to the promulgation of the General Law of Fisheries and Aquaculture No. 18,892 of 6 September 1991 and its amendments. This law regulates national fisheries and aquaculture activities throughout the country, and contains eleven regulations applicable to aquaculture. These regulations form a complete procedure of action relevant to the importation of aquatic species, to applicants for aquaculture concessions and authorisations, to the operation of these concessions and authorisations, and to ocean ranching systems. Due to the complexity of these regulations, important rules are still under study, while the remaining texts come into force on 1 September 1996. Formulating these rules involves consideration of current national and international regulations, the experience of farmers, the results of technical and scientific research, and bibliographical data. These regulations will form the cornerstone of Children aquaculture policy in confronting the challenges of the next century.

Animals↗

[Investigation of mites in the houses of atopic dermatitis (AD) patients, and clinical improvements by mite elimination].

Seasonal variations related to mites were investigated by the Methylene Blue Agar (MBA) method in the houses of 157 AD patients living in Tokyo. Many mites were counted in the dust from carpets, Japanese straw mats (Tatami) and the floor under Tatami. In most places, the number of mites was found to increase in summer. In winter, however, mite levels increased in sofas and Japanese seat cushions. On the other hand, only small numbers of mites were found in mite-proof products. Based on the above data, were recommended mite elimination by various scientific techniques was recommended for 34 severe AD patients. Mite levels and clinical symptoms were again checked after one year and two years in the same seasons. In 17 of the 34 cases, mite elimination was carried out completely. In these cases, the ratio of mite decrease to less than 30% was 82%, and the ratio of improvement of clinical symptoms (remarkable improvement + improvement) was 88%. Almost complete cure was noted in 7 cases. On the other hand, in the remaining 17 cases, mite elimination was performed incompletely in 12 cases, and was hardly done at all in 5 cases. The ratio of mite decrease to less than 30% was 47%, and the ratio of improvement of clinical symptoms was 35%. Therefore, it was concluded that investigation of mite levels following mite elimination procedures is a most recommendable treatment for severe AD patients who are hypersensitive to house dust mites.

Adolescent↗

Tissue engineering with adult stem cells in reconstructive surgery (review).

Tissue engineering is a multidisciplinary field combining biology and engineering along with clinical application to design, manufacture, modify, grow and maintain living tissue. This field has enjoyed tremendous growth in the past 10 years fueled by its potential role in regenerating new tissues and naturally healing injured or diseased organs. Many approaches to tissue engineering have been explored, including ex vivo de novo construction of tissues and strategies of in vivo induction of tissue regeneration. Interventions are hindered by factors such as rejection by the immune system, limited blood supply or morbidity of the donor site. Regardless of the approach, most researchers and clinicians agree that any successful tissue engineering construct will derive from a single unit, the cell. Because the engineering of tissue necessitates a sufficient number of tissue-specific cells with minimal donor site morbidity, a great deal of scientific effort has been directed towards stem cell research and the use of stem cells as a source of cells for new tissues. This review aims at outlining the role of stem cells in tissue engineering, focusing on the use of adult-derived stem cells as applied to the research and practice of plastic surgery.

Animals↗

Oocyte in-vitro maturation and follicle culture: current clinical achievements and future directions.

This paper reviews two recent developments in the field of assisted reproduction: in-vitro culture (IVC) of follicles and in-vitro maturation (IVM) of oocytes. Both in-vitro procedures for oocytes and immature follicles were developed so as to enable storage of ovarian cortical tissue and oocyte-cumulus complexes (OCC) from small follicles. Until now, complete in-vitro development from a primordial follicle up to ovulation has been achieved only in mice. Culture of ovarian cortex from large mammals and humans has revealed that the proliferation and differentiation of pre-granulosa cells is easily switched on, but that within a few days oocyte growth is often compromised. Culture of OCC from preantral follicles from sheep yielded antral follicles after 1 month in a serum-free system and the enclosed oocytes had almost doubled their diameter. Similar work in humans is ongoing, but no consistent successes have been reported as yet. In-vitro maturation of OCC from antral follicles has already been used clinically for more than 10 years. Inspired by the work on bovines, several in-vitro fertilization (IVF) clinics have applied IVM on OCC from different sizes of follicles. The culture conditions needed to provide a reasonable yield of developmentally competent oocytes have not been clearly defined, although some IVF groups have reported live births. To enable the development of consistent techniques of IVC and IVM, a more systematic and scientific approach is needed: use of defined culture media in combination with follicle stage-dependent supplements might improve our understanding of the minimal requirements for oocyte growth and maturation.

Animals↗