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91.
Development and evaluation of a protein microarray chip for diagnosis of hepatitis C virus 总被引:3,自引:0,他引:3
A protein chip diagnostic kit was developed for the diagnosis of hepatitis C virus (HCV) based on the protein chip technique and the immuno-concentration method. This kit was designed for low-density protein chips and also for the availability of multiple sample screening. Applicability of the chip was evaluated using 96 blood specimens and the results were compared to results of an anti-HCV enzyme immunoassay (EIA) test. With further development, the technology associated with the development of this chip could be applied to the simultaneous detection of multiple protein-protein, protein-ligand interactions. 相似文献
92.
Exploiting the potential of insects for in vivo pathogenicity testing of microbial pathogens 总被引:5,自引:0,他引:5
Conventional assays for quantifying the virulence of microbial pathogens and mutants have traditionally relied upon the use of a range of mammalian species. A number of workers have demonstrated that insects can be used for evaluating microbial pathogenicity and provide results comparable to those that can be obtained with mammals since one component of the vertebrate immune system, the innate immune response, remains similar to that found in insects. Larvae of the Greater Wax Moth Galleria mellonella have been used to evaluate the virulence of a range of bacterial and fungal pathogens and a correlation with the virulence of these microbes in mice has been established. This review highlights the similarities of the vertebrate and insect innate immune responses to infection and identifies the potential use of insects for the in vivo evaluation of the microbial pathogenicity. 相似文献
93.
We introduce concepts of external and internal complexity to analyze the relation between an adaptive system and its environment.
We apply this theoretical framework to the construction of models in a cognitive system and the selection between hypotheses
through selective observations performed on a data set in a recurrent process and propose a corresponding neural network architecture. 相似文献
94.
Splitting of fruits is a function of two-dimensional tension caused by different growth rates of tissues and turgor, especially water uptake shortly before harvest. In order to analyse the mechanical properties of spheroid plant material close to stress-strain conditions in vivo, a new hydraulic two-dimensional testing device was set up. Sweet cherry (Prunus avium L.) fruit skin was chosen as a model system. The recorded pressure-deflection curves were non-linear, with a considerable initial "lag phase" and a distinct increasing end part. Taking into account the special geometry, these curves could be modelled with a newly developed analytical approach based on linear elastic material behaviour. The results demonstrated good correlation if a modulus of elasticity ranging from 160 to 250 MPa for the cherry fruit skin was chosen. In addition, a mean strength value of 47 MPa was calculated based on the theory of thin shells and spheres. The results are compared with mechanical data found for fruits and other plant material. In order to test the theoretical approach, two- and one-dimensional tension tests were performed on packaging PE foil, revealing a mean modulus of 171 MPa in bi-axial tension, and 193 and 242 MPa in uni-axial tension, depending on the test speed. The results demonstrate that it seems to be feasible to use this method to analyse the two-dimensional stress-strain conditions of spheroid plant materials such as cherry fruit skins. It may be applied as a tool for crop testing to elucidate the mechanical basis of cracking susceptibility of fruits. 相似文献
95.
The comet assay for DNA damage and repair 总被引:9,自引:0,他引:9
Collins AR 《Molecular biotechnology》2004,26(3):249-261
The comet assay (single-cell gel electrophoresis) is a simple method for measuring deoxyribonucleic acid (DNA) strand breaks
in eukaryotic cells. Cells embedded in agarose on a microscope slide are lysed with detergent and high salt to form nucleoids
containing supercoiled loops of DNA linked to the nuclear matrix. Electrophoresis at high pH results in structures resembling
comets, observed by fluorescence microscopy; the intensity of the comet tail relative to the head reflects the number of DNA
breaks. The likely basis for this is that loops containing a break lose their supercoiling and become free to extend toward
the anode. The assay has applications in testing novel chemicals for genotoxicity, monitoring environmental contamination
with genotoxins, human biomonitoring and molecular epidemiology, and fundamental research in DNA damage and repair. The sensitivity
and specificity of the assay are greatly enhanced if the nucleoids are incubated with bacterial repair endonucleases that
recognize specific kinds of damage in the DNA and convert lesions to DNA breaks, increasing the amount of DNA in the comet
tail. DNA repair can be monitored by incubating cells after treatment with damaging agent and measuring the damage remaining
at intervals. Alternatively, the repair activity in a cell extract can be measured by incubating it with nucleoids containing
specific damage. 相似文献
96.
Biopharmaceuticals intended for humans are immunogenic in animals. Antibodies associated with their administration make it difficult to perform repeated-dose pharmacology and toxicology studies in animals. Despite suggestions to solve this problem with transgenic animal technology, an effective strategy has not yet been reported. The objective of the present study was to provide an efficient strategy to develop rats tolerant to biopharmaceuticals such as human gene-based proteins. The present study used transgenic rat lines (lines 311-6, 308-5, and 305-1) carrying a fusion gene designed to express the human growth hormone (hGH) gene under the control of the bovine S1 casein gene promoter. Three lactating females with the transgene, produced approximately 4mg/ml, 300g/ml, and 10ng/ml in their milk. Male 8-week-old rats from these three lines were immunized with hGH three times (week 0, 1, and 3 ) and the production of antibodies against hGH in their sera were examined at week 4. While the hGH serum antibody titers increased over 1000-fold in wild-type control rats, there was no detectable antibody against hGH in the sera of these three transgenic lines. Human growth hormone in their sera was undetectable (lines 308-5 and 305-1) or much lower than the endogenous biologic level of rat growth hormone (line 311-6). Importantly, lines 308-5 and 305-1 developed tolerance to hGH without detectable hGH in their sera and these lines will be very useful for the repeated dose pharmacology and toxicology studies. These results suggest that a milk protein promoter can be a useful tool to develop transgenic rats that are tolerant to biopharmaceuticals intended for humans. 相似文献
97.
The testing of Bayesian point null hypotheses on variance component models have resulted in a tough assignment for which no clear and generally accepted method exists. In this work we present what we believe is a succeeding approach to such a task. It is based on a simple reparameterization of the model in terms of the total variance and the proportion of the additive genetic variance with respect to it, as well as on the explicit inclusion on the prior probability of a discrete component at origin. The reparameterization was used to bypass an arbitrariness related to the impropriety of uninformative priors onto unbounded variables while the discrete component was necessary to overcome the zero probability assigned to sets of null measure by the usual continuous variable models. The method was tested against computer simulations with appealing results. 相似文献
98.
不测土条件下半定量施肥原理和模型评述 总被引:7,自引:0,他引:7
1 不测土条件下半定量推荐施肥的需求矿质营养学说是施肥最基本原理 ,它的诞生标志着人类主动施肥时期的开始。从早期的定性施肥阶段 ,发展到今天的定量施肥阶段 ,如何确定施肥量一直是施肥技术的核心和难点。测土是定量施肥或精确施肥的前提。然而 ,测土本身存在各种偏差或精度、测土需要费用 ,本文仅对代表性的不测土施肥模型及其原理进行评述。即使有了土壤有效养分的测定结果 ,如何将其转化为一季内土壤提供的养分量一直是个理论难题 ,特别是N素土壤供应量更为难测或难以估算。因此 ,如何在使用定量施肥模型的同时 ,而又将土壤养分因… 相似文献
99.
Validity of hair mineral testing 总被引:1,自引:0,他引:1
Shamberger RJ 《Biological trace element research》2002,87(1-3):1-28
The variance of testing was compared between the College of American Pathologists clinical survey and that of a recent review
about hair mineral testing. The review suggested that the accuracy of hair mineral testing was unreliable. In general, there
was a greater range of variance in the College of American Pathologists testing results. These latter results are based on
laboratory testing and are used as a “yardstick” to determine if a laboratory passes or fails that analyte and are considered
a “gold standard.” An extract, which resulted from a method that avoided the washing step, was compared among five laboratories.
Very good precision resulted, indicating that the varied washing steps used by the laboratories in a recent review were probably
the source of much variance.
Analysis of hair analysis seemed to yield important information in several historical or forensic cases involving Ludwig von
Beethoven, Napoleon Bonaparte, ex-US-presidents Zachary Taylor and Andrew Jackson, and Charles Hall, an Arctic explorer.
Several elements that were reviewed, including arsenic, cadmium, cobalt, germanium, lead, lithium, manganese, mercury, nickel,
and thallium, showed relationships between body burden, dosage, and exposure or toxicity. Evidence of toxicity could not be
found by measuring hair aluminum or vanadium. Chromium, selenium, and zinc seemed to have nutritional value. Ratios of hair
elements with clinical importance could not be found. 相似文献
100.
AIMS: An internal positive control for Cryptosporidium and Giardia monitoring was evaluated for use in routine water monitoring quality control. The control, known as ColorSeed C&G (BTF Pty Ltd, Sydney, Australia), is a suspension containing exactly 100 Cryptosporidium oocysts and 100 Giardia cysts that have been modified by attachment of Texas Red to the cell wall, allowing them to be differentiated from unmodified oocysts and cysts. The control enables recovery efficiencies to be determined for every water sample analysed. METHODS AND RESULTS: A total of 494 water samples were seeded with ColorSeed C&G and with unlabelled Cryptosporidium and Giardia and then analysed. Additionally, the robustness of the ColorSeed labelling was challenged with various chemical treatments. Recoveries were significantly lower for the ColorSeed Texas Red labelled Cryptosporidium and Giardia than recoveries of unlabelled Cryptosporidium and Giardia. However, the differences in recoveries were small. On average ColorSeed Cryptosporidium recoveries were 3.3% lower than unlabelled Cryptosporidium, and ColorSeed Giardia recoveries were 4% lower than unlabelled Giardia. CONCLUSIONS: ColorSeed C&G is suitable for use as an internal positive control for routine monitoring of both treated and raw water samples. SIGNIFICANCE AND IMPACT OF THE STUDY: The small differences in recoveries are unlikely to limit the usefulness of ColorSeed C&G as an internal positive control. The ColorSeed labelling was found to be robust after different treatments. 相似文献