Preparation of 14C-labeled algal samples for liquid scintillation counting

Four commonly used techniques for preparation of ¹⁴C-labeled algal samples on membranes for liquid scintillation counting were compared and a simple technique for apparent net assimilation measurement from aqueous samples was introduced. All four techniques yielded similar radioactivities from the test cultures and are thus suitable for measurements of ¹⁴C algal samples. The possibly carcinogenic solvent dioxane was not necessary with PCS scintillation cocktail for dissolving radioactivity from algae on filters.     

A simple program which processes liquid scintillation counting data from samples containing both 125I and 3H under conditions of varying quench

A simple program was written for a programmable calculator which enabled simultaneous measurement of ³H and ¹²⁵I by liquid scintillation counting. The program uses quench correction curves to calculate the effects of quench in each sample and calculates the amount of each isotope present by solving a linear equation set simultaneously.     

A carbon dioxide collection accessory for the rapid combustion apparatus for preparation of biological samples for liquid scintillation analysis

A carbon dioxide collection accessory is described for the previously reported combustion system for preparation of biological samples for liquid scintillation counting. A sample can be burned and collected every 3 min. Sample size is limited by the capacity of the solvent to absorb carbon dioxide without precipitation. The system can be used for collecting water as well as carbon dioxide, for double isotope counting. The method has a collection recovery of 97%, is calibrated by internal standards, and shows a coefficient of variation of 1.1%.     

Statistical analysis of relative labeled mass spectrometry data from complex samples using ANOVA

Statistical tools enable unified analysis of data from multiple global proteomic experiments, producing unbiased estimates of normalization terms despite the missing data problem inherent in these studies. The modeling approach, implementation, and useful visualization tools are demonstrated via a case study of complex biological samples assessed using the iTRAQ relative labeling protocol.     

A rapid, hygienic method for the preparation of fecal samples for liquid scintillation counting.

A method for the preparation of fecal samples for liquid scintillation counting is described which is rapid, hygienic, and inexpensive. By the use of a novel type of homogenizer, fecal samples can be homogenized while totally enclosed within a sealed, plastic bag, so reducing the possible risk of infection. The subsequent preparation of a clear solution suitable for liquid seintillation counting is performed using an “in-vial” digestion technique which enables any ¹⁴CO₂ released during digestion to be trapped within the vial.     

Parametric analysis of survival data for doubly irradiated animals

On the basis of their previously reported model of acute radiation sickness development the authors made a parametric analysis of the survival rate of mice after double exposure to ionizing radiation.     

A new combustion system for rapid preparation of biological samples for liquid scintillation counting.

A combustion tube equipped with two oxygen supply nozzles was developed for preparation of biological samples for liquid scintillation analysis. By using this new combustion system, relatively large quantities of biological tissues were easily burned within a few minutes and [¹⁴C]O₂ and/or [³H]₂O thus produced were promptly and quantitatively recovered. This system proved to have several advantageous characteristics, i.e., simple construction, easy and safe operation and no need of a catalyst such as cupric oxide for complete combustion.     

CGH-Explorer: a program for analysis of array-CGH data

SUMMARY: CGH-Explorer is a program for visualization and statistical analysis of microarray-based comparative genomic hybridization (array-CGH) data. The program has preprocessing facilities, tools for graphical exploration of individual arrays or groups of arrays, and tools for statistical identification of regions of amplification and deletion.     

Quantification of 32P-labeled samples in gel fragments using the flat-bed liquid scintillation counter

Quantification of 32P in bands after gel electrophoresis was performed using the flat-bed scintillation counter (Betaplate). The most convenient system involved placing fragments of dried gel between two glass fiber sheets, each previously sealed in a thin plastic bag with liquid scintillant. Good pulse-height spectra and counting efficiencies were obtained with low cross talk and background. The method has been used to quantify mRNA in RNA antisense-protection assays that were linear over a wide range (1-20000 cpm). Cross talk and background could be reduced further by an alternative technique utilizing plastic trays with shallow wells in which a solid scintillant had been melted. Fragments were immersed in the molten scintillant (90 degrees C), which was allowed to solidify, by cooling, before counting.     

Photoreactive insulin derivatives for the detection of the doubly labeled insulin receptor

Two different photoinsulins, the radioactive N(epsilonB29)-(4-azidosalicyloyl) insulin and the novel biotinylated N(epsilonB29)-(4-azidotetrafluorobenzoyl-biocytinyl) insulin, were synthesized in order to study the binding stoichiometry of insulin and the insulin receptor in a direct approach. Both derivatives were cross-linked simultaneously to the (alphabeta)(2) receptor. Insulin-receptor conjugates were formed that carry a radioactive label as well as a biotin label. The doubly labeled complexes were isolated by streptavidin-affinity chromatography. Analysis of both markers, the radioactive (125)I marker and the biotin marker, proved the existence of a covalent complex of one receptor molecule and two ligands. Thus, orthogonal photocross-linking is introduced as a method for the isolation and analysis of bivalent receptor complexes.     

TETRASAT: a program for the population analysis of allotetraploid microsatellite data

Microsatellite markers are quite popular due to their degree of polymorphism and efficiency; however, the utility of such markers for analysing allotetraploid species is often hampered by an inability to determine allele copy number for partial heterozygotes. tetrasat is a program that uses an iterative substitution process to account for all probable combinations of allele copy numbers in populations with partial heterozygote samples. The program subsequently calculates allele frequencies, and mean Hardy–Weinberg expected heterozygosity (H_E), Shannon–Weiner Diversity Index (H′) and Nei's measure of population differentiation (G_ST) are reported for each locus and population. Of equal importance is the calculation of statistical variability generated by the missing data and allele substitution process, which allows for assessment of the strength of conclusions drawn from the statistics.