Experiments Using Animal Models

The descriptions thus far reported of the pathologic anatomy of the CNS following in utero exposure to Hg and Hg-compounds must be considered too nonspecific and lacking in detail to allow an adequate understanding of the neuropathology of fetal MeHg poisoning on brain development. 

The clearance half-time of radioactivity in lactating mothers was 8.7 d, indicating a relative increase of clearance in lactating mothers compared to controls (10-14 d).  

The results of this study, which indicate a delay in dendritic arborization of Purkinje cells and a delay in the proliferative activity of external granule cells following in utero MeHg intoxication, clearly illustrate the value of a correlative morphological approach in bringing out some of the more subtle effects of MeHg upon the developing CNS. 

Experiments Using Human Fetai Brain Cel is In Vitro 

To test the hypothesis that MeHg causes abnormal neuronal migration, we have carried out a number of experiments using organotypic and monolayer cultures of human fetal brain cells obtained from aborted fetuses. Our studies, as well as those of others, have demonstrated that many of the developmental events that occur in normal fetal brain are repeated in cultures of fetal brain tissue. 

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Candidate genes can be selected using a variety of approaches such as literature searches, genes resulting from experiments in animal models, homology searches, and gene expression experiments. Studies testing even dozens of candidates at once exist for many complex diseases cardiovascular disease (83), osteoarthritis (84), and asthma (85) to name a few. 

Papers presented earlier In this symposium described a number of approaches which were used to determine bloavalla-blllty of dietary zinc. Experiments with animal models and human subjects were reported. Most scientists agree that as much Information as possible should be first obtained from In vitro and laboratory animal experiments. However, since results of vitro and animal experiments do not always agree with results of human experiments, research with human subjects Is ultimately required to establish dietary requirements of humans and to determine bloavallabllty of nutrients to humans. 

What little information that is available on the activity of topicals against viruses on mucous membranes comes from experiments using animals [13,14]. Ethical considerations, costs, and the general difficulties of working with animals models severely limit a wider application of such test protocols, especially in the initial development and screening of formulations. The recent introduction of the human umbilical cord as a surrogate for mucous membranes is an attempt at addressing this gap [3], and preliminary experiments with this model show its potential for application in studies on virus survival and inactivation on mucous membranes [72]. 

The most commonly used animal model to study GAS pharyngitis is the mouse upper respiratory tract infection model (14,15,16). However, mice do not develop a true pharyngitis and only a relatively few animals become colonized even when high concentrations of inocula are used. Moreover, in our experience the data obtained with this model are poorly reproducible, and because the blood volume of the mouse is small the ability to easily perform many standard immunologic assays is limited. In addition, several gas virulence factor do not act on mouse molecules. Therefore, the relevance, significance, and usefulness of the murine model of GAS pharyngitis is limited. Several independent studies indicate that non-human primates may provide a more suitable model to study GAS pharyngitis animals are successfully colonized by GAS, and limited data indicate that the infections mimicked the humoral immune response characteristic for human disease (70,77,75,79,20). 

The use of saw palmetto in BPH has continued as the main focus of numerous reports over the last decade. Such reports include in vivo experiments in animal models, in vitro experiments in prostate cells, and human clinical trials. The majority of these reports were in favor of saw palmetto s efficacy in improving lower urinary tract symptoms. Some studies showed that it favorably compared with finasteride and tamsulo-sin, the first-line treatments for There is no consensus yet on the mechanism of action of saw palmetto, but one or more of the following may be involved 5-a-reductase inhibition, indirect sympathomimetic effect (tti-adrenergic receptor binding), anti-inflammatory and/or hormonal antiandrogenic effects.2 2 3° 3i... 

I, Introduction to quantum phenomena. This section takes the students into the realm of atoms and molecules and uses mathematical modeling and computer simulation, animations and visualization to give them experience in the phenomena that must be described by QM and cannot be described by NM. The simulations could cover the following processes among others ... 

The effect of cellular GSH depletion on /wa/K has also been studied using this model. Guinea-pig ventricular myocytes prepared from DEM-treated animals have been used to determine the effect of glutathione depletion on /xa/K- Myocytes prepared from DEM-treated animals showed a similar profile of glutathione content modification to that previously described in experiments using sarcolemmal homogenates. GSH levels in DEM-treated were reduced from a control value of 0.2 0.04 to 0.02 0.01 nmol/1 X10 cells. Jni/k at 0 mV was reduced from a control value of 1.1 0.12 to... 

Before discussing the animal data it is important to note that caffeine is metabolized differently in experimental animals than it is in humans. This is particularly so in the rat, which is the most common experimental model used. Therefore results in animals, either positive or negative, cannot be directly applied to humans. However, since caffeine itself and some of its metabolites are present in both the animal experiments and during human exposure, an adverse effect of caffeine in an animal model should be verified or excluded in the human. 

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