Accomplishments of the Trustees and laboratory staff of the Biological Stain Commission, 2002–2013

During the 12 years from 2002 to 2013, the Trustees and laboratory personnel of the Biological Stain Commission (BSC) can claim many accomplishments. These accomplishments are itemized under 11 categories: continuous publication of the official journal, Biotechnic & Histochemistry; production of four special issues of Biotechnic & Histochemistry devoted to specific dyes or stains; standardization of staining and dye purity; mechanisms of staining and prediction of dye behavior; publication of books or book chapters; effects of fixation and processing on staining; cancer research; immunohistochemistry; BSC Laboratory activities; miscellaneous publications; and administrative accomplishments.     

Glyoxal fixation: how it works and why it only occasionally needs antigen retrieval

Over the past 13 years, glyoxal has become the leading alternative to formaldehyde as a histological fixative because of its low inhalation risk, faster reaction rate and selective control over crosslinking. The latter attribute is especially important, because most of the difficulties relating to use of formaldehyde-fixed specimens for immunohistochemistry stem from its aggressive crosslinking behavior. With suitable catalysts or other reaction accelerators, glyoxal forms 2-carbon adducts with nearly all end groups in proteins and carbohydrates, leaving most of them unimpaired for subsequent immunohistochemical demonstration. Only arginine is seriously impaired by the formation of imidazoles, which is the basis for the well known arginine blockade method using glyoxal. A special glyoxal-specific antigen retrieval method using high pH and high temperature effectively reverses the blockade and restores immunoreactivity. Other methods for antigen retrieval are rarely beneficial and in most cases damage the specimen. Special stains work well, except silver methods for Helicobacter pylori. Routine hematoxylin and eosin preparations exhibit clarity and cellular detail rarely seen with formaldehyde.     

News from the Biological Stain Commission No. 15

In the 15^th issue of News from the Biological Stain Commission (BSC), under the heading of Regulatory affairs, the Biological Stain Commission’s International Affairs Committee presents information from the plenary meetings of the International Standards Organization ISO/TC 212 Clinical laboratory testing and in vitro diagnostic test systems held on August 22–24, 2012 in Berlin, Germany. An additional discussion of the use of food dyes in India also is included.     

ODOR DISCRIMINATION BY FROG OLFACTORY RECEPTORS

Single unit activity of olfactory receptors was recorded inthe frog. Seventy per cent of the receptors displayed a restingfrequency lower than 20 spikes min^–1. A 20 ways olfactometerwas designed to automatically stimulate the olfactory epitheliumwith 20 highly purified, simple odorants belonging to severalchemical series, each at a single supraliminal concentration.Twenty three cells failed to respond to any of the 20 stimuli.Following a total of 1160 stimulations delivered to 58 receptorcells, 241 activating and 59 inhibitory responses were recorded,leading to an overall selectivity of 25.8%. Twelve units wereexcited by only one of the 20 chemicals. The activating and inhibitory responses were submitted to mathematicalprocedures (calculation of the Pearson's ‘r’ correlationcoefficient, Benzecri's analysis of correspondences) in orderto determine similarities or proximities between odorants accordingto the response profiles of the receptors. The odour space builtfrom these data was clearly multidimensional. The five primaryaliphatic alcohols of the sample failed to exhibit any specialinter-relationship, except the propanolbutanol pair. Camphorwas quite unrelated to the other chemicals. Six odorants whichpossess in common the aromatic nucleus were found to be relatedby high correlation coefficients; they grouped themselves ina cluster in factor analysis diagrams. They are: benzene, naphthalene,anisole, acetophenone and the almond pair nitrobenzene-benzaldehyde.