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Papers by Richard Horobin
Encyclopedia of Life Sciences, 2001
Histochemical staining colour-codes biological structures and biomolecules, facilitating microsco... more Histochemical staining colour-codes biological structures and biomolecules, facilitating microscopic observation. This answers several questions simultaneously: what is this structure or molecule, where is it found, and how much of it is present
Biotechnic & Histochemistry, Mar 8, 2010
... For puzzling abbreviations and acronyms, we refer as usual to Appendix B in Lyon and Horobin ... more ... For puzzling abbreviations and acronyms, we refer as usual to Appendix B in Lyon and Horobin (2007) and previous editions of News from the BSC. ... reference materials guidelines dealt with by the ISO Committee on Reference Materials (REMCO); ...
Biotechnic & Histochemistry, Feb 5, 2020
Alcian blue dyes are copper phthalocyanines with a variety of cationic side chains; they are usef... more Alcian blue dyes are copper phthalocyanines with a variety of cationic side chains; they are useful for staining carbohydrate polyanions while avoiding staining of nucleic acids. The properties of the original alcian blue and of similar dyes with published chemical structures are reviewed here. Variation among samples submitted to the Biological Stain Commission (BSC) for certification has led to the recognition of two types of commercially available alcian blue at this time. The designation "alcian blue 8G or equivalent" is reserved for dyes that resemble alcian blue 8GX manufactured in the 1960s (CI 74240; ingrain blue 1). These dyes react with alkali to form an insoluble pigment that cannot be re-dissolved in acid. The name "alcian blue variant" is for similar dyes that do not form insoluble pigments; an alkali-induced precipitate, if formed, re-dissolves with acidification. For certification by the BSC, both types of alcian blue must dissolve in 3% acetic acid to make a 1% solution (pH close to 2.5), which must provide selective coloration of intestinal mucus, cartilage and mast cells, but not of nuclei. After alcian blue staining and treatment with 0.03 M Na 2 CO 3 or Li 2 CO 3 to convert the bound dye to a pigment, the Feulgen stain for DNA is applied. Dyes to be certified as alcian blue 8G or the equivalent must resist extraction by the 5 M HCl used in the Feulgen reaction. Dyes to be certified as alcian blue variant are not required to be convertible to acid-insoluble pigments, but they must dissolve easily in water at pH 5.7 containing 0.5 M magnesium chloride and the dye must remain in solution for at least 24 h. A critical electrolyte concentration (CEC) staining test also is described; this must be passed for certification of an alcian blue variant. Successful CEC staining is also a desirable property of alcian blue 8G or equivalent, but not essential for certification of an otherwise satisfactory batch. The spectrophotometric criteria for alcian blue dyes also are revised; a wider range of absorption maximum (605-634 nm) is allowed. The dye powders used in published staining techniques with the original alcian blue 8G were 40-60% dye, but some modern alcian blue dyes have dye content as high as 90%. The BSC's assay for dye content is not a criterion for certification, but it should influence the amount of dye to include in a staining solution.
Journal of Chromatography A, 1969
Current Medicinal Chemistry, Apr 1, 2007
Histochemical Journal, Aug 1, 1990
A numerical method for selecting low toxicity plasticizers for glycol methacrylate (GMA) embeddin... more A numerical method for selecting low toxicity plasticizers for glycol methacrylate (GMA) embedding mixtures is described. It involves use of various numerical parameters, namely; molecular weight, melting point, solubility parameter, and toxicity data. On the basis of these parameters, nine plasticizers were selected. Their effects on microtomy and tissue processing, and also their influence on tissue morphology and staining, were investigated. For tissue processed at low temperatures into GMA, using ethanol dehydration, the following compounds were as satisfactory as 2-butoxyethanol whilst being less toxic: 9 2-isopropoxyethanol, 2-(2-methoxyethoxy)ethanol, 2-(2-ethoxyethoxy)ethanol, 2-(n-butoxyethoxy)ethanol. However for tissues processed using the plasticizer as dehydrating agent, the optimum plasticizers were 2-isopropoxyethanol, 2-(2methoxyethoxy)ethanol and 2-(2-ethoxyethoxy)ethanol. It is possible to give a numerical specification of the preferred plasticizers, and for the first procedure this is: a solubility parameter in the range 21-26 j~-15 or higher, a melting point well below 0 ~ C, and a rat oral LDs0 >12.52 mmol kg-1. It was also possible to analyse the differential effects of the dehydrating agents on histochemical and enzyme histochemical staining on a numerical basis, using a structure-activity relations approach.
Taylor & Francis eBooks, Aug 13, 2020
Biotechnic & Histochemistry, Dec 4, 2018
Journal of Histotechnology, Dec 1, 1996
Page 1. Glycol Methacrylate Embedding for Light Microscopy: Basic Principles and Trouble-S hootin... more Page 1. Glycol Methacrylate Embedding for Light Microscopy: Basic Principles and Trouble-S hooting Peter 0. Gerrits* and Richard W. ~orobin' :'; Department of Anatomy and Embryology, University of Groningen, The Netherlands ...
Biotechnic & Histochemistry, Jul 19, 2022
Neuroscience Letters, Dec 1, 1983
Retrograde axonal transport of the fluorescent compound SITS has been described as occurring only... more Retrograde axonal transport of the fluorescent compound SITS has been described as occurring only from axon terminals and not from axons of passage. Injection of 4 different commercially available samples of SITS into terminations of cerebellar pathways in the rat revealed that only one sample produced retrogradely labelled neurones. Chemical analysis suggested that this was due to a unique fluorescent component (not SITS). This sample also contained other fluorescent components one of which, present in two other samples, produced paroxysmal motor disturbances. All of the samples examined contained several other fluorescent compounds.
Stain technology, 1971
ABSTRACT
Self & Society, 1980
This is the second of our two special issues on Co-Counselling. Last month JohnHeron covered the ... more This is the second of our two special issues on Co-Counselling. Last month JohnHeron covered the development of co-counselling with particular reference to the history and politics of the movement and Rose Evison described theprocesses and assumptions. This month Richard Horobin outlines the theoretical perspective and incorporates a guide to co-counselling practice and the way it links with other systems of growth and development. Taken together, these two volumes provide a comprehensive study of the practice of this most widespread and exciting self development technique.
Encyclopedia of Life Sciences, 2001
Histochemical staining colour-codes biological structures and biomolecules, facilitating microsco... more Histochemical staining colour-codes biological structures and biomolecules, facilitating microscopic observation. This answers several questions simultaneously: what is this structure or molecule, where is it found, and how much of it is present
Biotechnic & Histochemistry, Mar 8, 2010
... For puzzling abbreviations and acronyms, we refer as usual to Appendix B in Lyon and Horobin ... more ... For puzzling abbreviations and acronyms, we refer as usual to Appendix B in Lyon and Horobin (2007) and previous editions of News from the BSC. ... reference materials guidelines dealt with by the ISO Committee on Reference Materials (REMCO); ...
Biotechnic & Histochemistry, Feb 5, 2020
Alcian blue dyes are copper phthalocyanines with a variety of cationic side chains; they are usef... more Alcian blue dyes are copper phthalocyanines with a variety of cationic side chains; they are useful for staining carbohydrate polyanions while avoiding staining of nucleic acids. The properties of the original alcian blue and of similar dyes with published chemical structures are reviewed here. Variation among samples submitted to the Biological Stain Commission (BSC) for certification has led to the recognition of two types of commercially available alcian blue at this time. The designation "alcian blue 8G or equivalent" is reserved for dyes that resemble alcian blue 8GX manufactured in the 1960s (CI 74240; ingrain blue 1). These dyes react with alkali to form an insoluble pigment that cannot be re-dissolved in acid. The name "alcian blue variant" is for similar dyes that do not form insoluble pigments; an alkali-induced precipitate, if formed, re-dissolves with acidification. For certification by the BSC, both types of alcian blue must dissolve in 3% acetic acid to make a 1% solution (pH close to 2.5), which must provide selective coloration of intestinal mucus, cartilage and mast cells, but not of nuclei. After alcian blue staining and treatment with 0.03 M Na 2 CO 3 or Li 2 CO 3 to convert the bound dye to a pigment, the Feulgen stain for DNA is applied. Dyes to be certified as alcian blue 8G or the equivalent must resist extraction by the 5 M HCl used in the Feulgen reaction. Dyes to be certified as alcian blue variant are not required to be convertible to acid-insoluble pigments, but they must dissolve easily in water at pH 5.7 containing 0.5 M magnesium chloride and the dye must remain in solution for at least 24 h. A critical electrolyte concentration (CEC) staining test also is described; this must be passed for certification of an alcian blue variant. Successful CEC staining is also a desirable property of alcian blue 8G or equivalent, but not essential for certification of an otherwise satisfactory batch. The spectrophotometric criteria for alcian blue dyes also are revised; a wider range of absorption maximum (605-634 nm) is allowed. The dye powders used in published staining techniques with the original alcian blue 8G were 40-60% dye, but some modern alcian blue dyes have dye content as high as 90%. The BSC's assay for dye content is not a criterion for certification, but it should influence the amount of dye to include in a staining solution.
Journal of Chromatography A, 1969
Current Medicinal Chemistry, Apr 1, 2007
Histochemical Journal, Aug 1, 1990
A numerical method for selecting low toxicity plasticizers for glycol methacrylate (GMA) embeddin... more A numerical method for selecting low toxicity plasticizers for glycol methacrylate (GMA) embedding mixtures is described. It involves use of various numerical parameters, namely; molecular weight, melting point, solubility parameter, and toxicity data. On the basis of these parameters, nine plasticizers were selected. Their effects on microtomy and tissue processing, and also their influence on tissue morphology and staining, were investigated. For tissue processed at low temperatures into GMA, using ethanol dehydration, the following compounds were as satisfactory as 2-butoxyethanol whilst being less toxic: 9 2-isopropoxyethanol, 2-(2-methoxyethoxy)ethanol, 2-(2-ethoxyethoxy)ethanol, 2-(n-butoxyethoxy)ethanol. However for tissues processed using the plasticizer as dehydrating agent, the optimum plasticizers were 2-isopropoxyethanol, 2-(2methoxyethoxy)ethanol and 2-(2-ethoxyethoxy)ethanol. It is possible to give a numerical specification of the preferred plasticizers, and for the first procedure this is: a solubility parameter in the range 21-26 j~-15 or higher, a melting point well below 0 ~ C, and a rat oral LDs0 >12.52 mmol kg-1. It was also possible to analyse the differential effects of the dehydrating agents on histochemical and enzyme histochemical staining on a numerical basis, using a structure-activity relations approach.
Taylor & Francis eBooks, Aug 13, 2020
Biotechnic & Histochemistry, Dec 4, 2018
Journal of Histotechnology, Dec 1, 1996
Page 1. Glycol Methacrylate Embedding for Light Microscopy: Basic Principles and Trouble-S hootin... more Page 1. Glycol Methacrylate Embedding for Light Microscopy: Basic Principles and Trouble-S hooting Peter 0. Gerrits* and Richard W. ~orobin' :'; Department of Anatomy and Embryology, University of Groningen, The Netherlands ...
Biotechnic & Histochemistry, Jul 19, 2022
Neuroscience Letters, Dec 1, 1983
Retrograde axonal transport of the fluorescent compound SITS has been described as occurring only... more Retrograde axonal transport of the fluorescent compound SITS has been described as occurring only from axon terminals and not from axons of passage. Injection of 4 different commercially available samples of SITS into terminations of cerebellar pathways in the rat revealed that only one sample produced retrogradely labelled neurones. Chemical analysis suggested that this was due to a unique fluorescent component (not SITS). This sample also contained other fluorescent components one of which, present in two other samples, produced paroxysmal motor disturbances. All of the samples examined contained several other fluorescent compounds.
Stain technology, 1971
ABSTRACT
Self & Society, 1980
This is the second of our two special issues on Co-Counselling. Last month JohnHeron covered the ... more This is the second of our two special issues on Co-Counselling. Last month JohnHeron covered the development of co-counselling with particular reference to the history and politics of the movement and Rose Evison described theprocesses and assumptions. This month Richard Horobin outlines the theoretical perspective and incorporates a guide to co-counselling practice and the way it links with other systems of growth and development. Taken together, these two volumes provide a comprehensive study of the practice of this most widespread and exciting self development technique.