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Alternative Protocols (alternative + protocol)

Distribution by Scientific Domains

Medical Sciences	40%
Chemistry	40%

Selected Abstracts

A modified choline-deficient, ethionine-supplemented diet protocol effectively induces oval cells in mouse liver

HEPATOLOGY, Issue 3 2001
Barbara Akhurst
Several reliable and reproducible methods are available to induce oval cells in rat liver. Effective methods often involve inhibiting proliferation in hepatocytes using an alkylating agent, then subjecting the rat to partial hepatectomy (PH). The surgery is difficult to perform reproducibly in mice. Approaches that do not include partial hepatectomy, such as administration of D -galactosamine, are ineffective in mice. We found that a choline-deficient, ethionine-supplemented (CDE) diet, which is very effective in rats, leads to high morbidity and mortality when administered to mice. This article outlines an alternative protocol by which a CDE diet can be administered to mice. This diet is shown to be highly effective for oval cell induction, without causing high mortality. It takes less time and is at least as effective as other commonly used protocols for inducing oval cells in mice. (HEPATOLOGY 2001;34:519-522.) [source]

Popliteal lymph node assay: facts and perspectives

JOURNAL OF APPLIED TOXICOLOGY, Issue 6 2005
Guillaume Ravel
Abstract The popliteal lymph node assay (PLNA) derives from the hypothesis that some supposedly immunemediated adverse effects induced by certain pharmaceuticals involve a mechanism resembling a graft-versus-host reaction. The injection of many but not all of these compounds into the footpad of mice or rats produces an increase in the weight and/or cellularity of the popliteal lymph node in the treated limb (direct PLNA). Some of the compounds known to cause these adverse effects in humans, however, failed to induce a positive PLNA response, leading to refinements of the technique to include pretreatment with enzyme inducers, depletion of CD4+ T cells or additional endpoints such as histological examination, lymphocyte subset analysis and cytokine fingerprinting. Alternative approaches have been used to improve further the predictability of the assay. In the secondary PLNA, the test compound is injected twice in order to illicit a greater secondary response, thus suggesting a memory-specific T cell response. In the adoptive PLNA, popliteal lymph node cells from treated mice are injected into the footpad of naive mice; a marked response to a subsequent footpad challenge demonstrates the involvement of T cells. Finally, the reporter antigens TNP-Ficoll and TNP-ovalbumin are used to differentiate compounds that induce responses involving neo-antigen help or co-stimulatory signals (modified PLNA). The PLNA is increasingly considered as a tool for detection of the potential to induce both sensitization and autoimmune reactions. A major current limitation is validation. A small inter-laboratory validation study of the direct PLNA found consistent results. No such study has been performed using an alternative protocol. Other issues include selection of the optimal protocol for an improved prediction of sensitization vs autoimmunity, and the elimination of false-positive responses due to primary irritation. Finally, a better understanding of underlying mechanisms is essential to determine the most relevant endpoints. The confusion resulting from use of the PLNA to predict autoimmune-like reactions as well as sensitization should be clarified. Interestingly, most drugs that were positive in the direct PLNA are also known to cause drug hypersensitivity syndrome in treated patients. This observation is expected to open new avenues of research. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Automated seeding for the optimization of crystal quality

JOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 4 2010
Sahir Khurshid
With the advent of structural genomics a variety of crystallization techniques have been automated and applied to high-throughput pipelines, yet seeding, which is the most common and successful optimization method, is still being performed predominantly manually. The aim of this study was to devise simple automated seeding techniques that can be applied in a routine manner using existing robots and not requiring special tools. Two alternative protocols for automated seeding experiments are described. One involves the delivery of microcrystals from stock to target wells using the robot dispensing tip as a seeding tool. The second harnesses an animal whisker as the seeding tool. Larger and better ordered crystals were obtained using both techniques. [source]

How you count counts: the importance of methods research in applied ecology

JOURNAL OF APPLIED ECOLOGY, Issue 5 2008
Chris S. Elphick
Summary 1Methods papers play a crucial role in advancing applied ecology. Counting organisms, in particular, has a rich history of methods development with many key advances both in field sampling and the treatment of resulting data. 2Most counts, however, have associated errors due to portions of the population of interest being unavailable for detection (e.g. target population not fully sampled; individuals present but not detectable), detection mistakes (e.g. detectable individuals missed; non-existent individuals recorded), or erroneous counts (e.g. large groups miscounted; individuals misidentified). 3Developments in field methods focus on reducing biases in the actual counts. Simultaneously, statisticians have developed many methods for improving inference by quantifying and correcting for biases retrospectively. Prominent examples of methods used to account for detection errors include distance sampling and multiple-observer methods. 4Simulations, in which population characteristics are set by the investigator, provide an efficient means of testing methods. With good estimates of sampling biases, computer simulations can be used to evaluate how much a given counting problem affects estimates of parameters such as population size and decline, thereby allowing applied ecologists to test the efficacy of sampling designs. Combined with cost estimates for each field method, such models would allow the cost-effectiveness of alternative protocols to be assessed. 5Synthesis and applications. Major advances are likely to come from research that looks for systematic patterns, across studies, in the effects of different types of bias and assumption violation on the ecological conclusions drawn. Specifically, determining how often, and under what circumstances, errors contribute to poor management and policy would greatly enhance future application of ecological knowledge. [source]

Preovulatory Follicle Development in Goats Following Oestrous Synchronization with Progestagens or Prostaglandins

REPRODUCTION IN DOMESTIC ANIMALS, Issue 1 2008
D Fernandez-Moro
Contents The study reports on differences in the dynamics of growth and functionality of preovulatory follicles in response to oestrous synchronization, either by the administration of two doses of prostaglandin or by an intravaginal progestagen sponge, in goats. The progestagen-treated group (n = 8) showed more follicles of preovulatory size (,5.5 mm) than the cloprostenol group (n = 8) during the follicular phase (4.5 ± 0.6 vs 1.9 ± 0.2, p < 0.01). The diameters of the largest follicles (LF1, LF2 and LF3) were also larger in the progestagen group (LF1, 7.8 ± 0.3 vs 7.0 ± 0.2 mm, p < 0.05; LF2, 6.7 ± 0.2 vs 5.6 ± 0.2 mm, p < 0.01; LF3, 5.5 ± 0.3 vs 4.2 ± 0.2 mm, p < 0.01). The study of the preovulatory follicles showed that 27.2% (3/11) of the follicles were in the static phase in the cloprostenol group, whilst 71.4% (10/14) were static in progestagen group (p < 0.05). Higher plasma oestradiol levels were recorded in the progestagen-treated goats during the 48 h prior to cloprostenol injection or progestagen withdrawal (4.2 ± 0.4 vs 3.0 ± 0.2 pg/ml, p < 0.05). In conclusion, goats with oestrus synchronized by progestagen showed a higher number of preovulatory-sized follicles, but a decreased oestradiol secretion when compared with does with oestrus synchronized by using prostaglandin analogues. These would support the development of alternative protocols for assisted reproduction. [source]