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At least 1,225 records · Page 68Linked to original sources
PubMed1981

Autopsy sampling and elemental analysis: errors arising from post-mortem changes.

The implication of post-mortem changes such as cell swelling, imbibition and autolysis on the elemental composition of body organs has been studied in rats. Liver has been chosen as an example. Retaining the liver inside the intact dead body for different periods of time at ambient temperature induced significant changes in its weight due to post-mortem tissue degeneration. Livers from animals that were frozen at -15 degrees C also showed significant decreases in weight when they were thawed on the third day. The effect of these changes on the concentrations of various elements depended on the association of the elements with extracellular fluid and intracellular components. For example, concentration of K+ was affected more by the lysis of the cell and sustained losses up to 30 per cent. in relation to the control values, while the total content was reduced by more than 40 per cent. as a result of both lysis and tissue liquefaction. For Na+, differences ranging from +10 to -20 per cent. in concentrations and +20 to -40 per cent. in total content were observed which could be explained by the movement of fluid in and out of the organ. Among trace elements, variation observed for iron ranged from -20 to +40 per cent., while both copper and zinc were found to fluctuate between -20 and +20 per cent. The loss observed in the total content in the liver for the five trace elements studied (Cu, Fe, Mn, Rb and Zn) was found to be about 20 to 40 per cent.

Animals↗
PubMed2000

Rapid genotyping of varicella-zoster virus vaccine and wild-type strains with fluorophore-labeled hybridization probes.

We developed a single-tube rapid method for the detection and differentiation of varicella-zoster virus (VZV) vaccine and wild-type strains that combines rapid-cycle PCR with wild-type-specific fluorescent probe melting profiles for product genotyping. A region including the polymorphic site in VZV open reading frame (ORF) 62 was amplified in the presence of two fluorescence-labeled hybridization probes. During the annealing step of the thermal cycling, both probes bound to their complementary sequences in the amplicon, resulting in resonance energy transfer, thus providing real-time fluorescence monitoring of PCR. Continuous acquisition of fluorescence data during a melting curve analysis at the completion of PCR revealed that loss of fluorescence occurred in a strain-specific manner as the detection probe, which was fully complementary to the wild-type VZV ORF 62 region, melted off the template. Use of this method allowed genotyping of samples within minutes after the completion of PCR, eliminating the need for post-PCR sample manipulation. In addition to reducing the time required to produce a result, this method substantially reduces the risk of contamination of the final product as well as the risk of sample tracking errors. The genotypes of 79 VZV-positive samples determined by this fluorescent resonance energy transfer (FRET) method were identical to the genotypes obtained by conventional PCR and restriction fragment length polymorphism analysis. The genotyping of VZV strains by the FRET method is a rapid and reliable method that is suitable for typing and that is also practical for use for the processing of large numbers of specimens.

Base Sequence↗
PubMed1988

Sources of error in neonatal blood sampling.

Significant underestimation of blood electrolyte concentrations may occur if less than 1 ml of blood is withdrawn from an indwelling arterial line before taking the sample for analysis. Compared with arterial samples capillary samples give significant overestimations of potassium concentration and carbon dioxide tension, and significant underestimation of oxygen tension.

Arteries↗
PubMed1985

Basilar venous plexus of the posterior fossa: a potential source of error in petrosal sinus sampling.

Sampling of serum from the inferior petrosal sinus can provide important information about the source of elevated adrenocorticotropic hormone (ACTH) levels. This often leads to improved results of pituitary surgery for Cushing disease. The authors describe a successful catheterization technique and illustrate the venous anatomy of the inferior petrosal sinuses and basilar plexus.

Adenoma↗
PubMed2000

Performance of the annular denuder system with different arrangements for HNO3 and HNO2 measurements in Taiwan.

Experiments on different annular denuder system (ADS) arrangements for sampling nitrous acid (HNO2) and nitric acid (HNO3) gases were conducted in this study to evaluate their sampling artifacts. The evaluation basis is the one that employed one sodium chloride denuder for sampling HNO3 gas and two sodium carbonate (Na2CO3) denuders for sampling HNO2 gas, which is a commonly employed ADS arrangement in many field applications in the United States. A field study was conducted in Hsinchu, Taiwan, and the results indicated that this ADS arrangement may yield over 80% relative errors for HNO3 gas. It also showed that the relative errors for HNO2 gas can be less than 10% as sampled with only one Na2CO3 denuder. This is attributed to the fact that the ambient HNO3 concentration measured in this study was relatively low while the HNO2 concentration was high, as compared to typical concentrations of these two gases measured in the United States. The sampling error of HNO3 gas may be due to high concentrations of N-containing interfering species present in Taiwan's atmosphere. Because the relative sampling errors of HNO3 and HNO2 gases depend mainly on their concentrations in the atmosphere as well as concentrations caused by interfering species, the risk for high error while measuring low HNO2 concentrations by only one Na2CO3 denuder is also possible. As a result, it is suggested that pretests are necessary to evaluate possible sources and degrees of sampling errors before field sampling of HNO2 and HNO3 gases. The sampling errors of these two gases can, therefore, be minimized with a better arrangement of the ADS.

Air Pollutants↗
PubMed1981

Sample viscosity can be a source of analytical error when discrete sampler-dilutors are used.

Total protein concentration in the serum of a patient with hyperviscosity syndrome differed as measured by the biuret procedure in the DuPont aca (80 g/L) and the SMA 12/60 (105 g/L), owing to viscosity-dependent errors with the aca sampling system; the magnitude depended on sample temperature and volume of sample aspirated. This kind of error was not observed with the SMA 12/60 and was far less severe when a Micromedic sampler-dilutor was tested. It could be eliminated in the case of the aca by adding sample to test packs with a syringe rather than with the aca automated sampler-dilutor. We thus recommend use of the syringe method when unusually viscous samples (serum or other body fluids) are analyzed in the aca.

Autoanalysis↗