The Haydn Orchestra

Hughes, Rosemary

doi:10.2307/935198

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“…Dahlia is a useful vital dye for various cytoplasmic inclusions.Basic fuchsine can be converted by sulphurous acid to a colourless substance that becomes coloured in the presence of aldehydes. This forms the basis of certain important histochemical tests(p. 308).Acid fuchsine is one of the best dyes for mitochondria (p 241),. and it can also be used for the differential colouring of collagen, though other acid dyes of the same groupmethyl blue, aniline DYEING blue WS, and light greenare preferable for this purpose.…”

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Principles of biological microtechnique; a study of fixation and dyeing

Baker¹

1958

185

172

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The Reactions of Fixatives with Proteins, i. The Visible Effects 31 3 The Reactions of Fixatives with Proteins. 2. The Chemical Changes 4 The Reactions of Fixatives with Tissues and Cells: Methods of Research 5 Primary Fixatives Considered Separately, i . Coagulants 6 Primary Fixatives Considered Separately. 2. Noncoagulants III 7 Fixative Mixtures PART II: DYEING 8 Introduction to the Chemical Composition of Dyes 9 The Classification of Dyes 10 The Direct Attachment of Dyes to Tissues 1 1 The Indirect Attachment of Dyes to Tissues 12 The Differential Action of Dyes 13 Metachromasy 14 The Blood Dyes 15 '^e specially the latter's lactophenol. Amann called his fluids Beohachtiingsmedien, to indicate that they not only prevented the decay of tissues, but were media in which cells might remain during microscopical examination. It is desirable that research FIXATIONLiving cytoplasm commonly has a refractive index (r.i.) in the neighbourhood of 1-353;*^^'*^^t hat is to say, not very much higher than that of the saline solutions in which cells are commonly immersed for vital study. An aqueous solution of sodium chloride at 0*9% has an r.i. of i*335.^^-"-When cells are examined alive in such media, a w^ater-immersion objective w^ill give almost as good resolution as a first-rate oil-immersion objective, for the high numerical aperture of the latter will be partly wasted. One may surround living cells with innocuous media of the same r.i. as the cytoplasm ** and thus obtain slightly higher resolution (as well as gaining other advantages), but the difference will not be great. As soon, however, as a fixative acts, a profound change occurs. The evidence suggests ** that the protoplasm is now represented by interlacing sub-microscopic fibres having the r.i. of dry protein (about 1*54). These fibres lie in water, if the fixative is aqueous; this can be replaced by media of any desired refractive index. If a medium of r.i. close to that of dry protein is used (Canada balsam, for instance), two results ensue: almost perfect transparency is obtained (which may be modified as desired by the use of dyes), and oil-immersion objectives can be used at their full aperture. This fact should not, however, be too strongly stressed, for the making of a permanent microscopical preparation involves considerable shrinkage of the tissues of organisms (p. 76), and this reduces or nullifies the advantage of higher microscopical resolution. The advantage can be fully secured only if the object to be examined happens to be unshrinkable by the processes involved in making a permanent preparation. The valves of diatoms provide an example. Some of the constituent parts of organisms do not require fixation, because they are not subject to autolysis and are resistant to bacteria and moulds and to most of the reagents ordinarily used in microtechnique. Examples are chitin, cellulose, scleroproteins, certain inorganic crystals, and amorphous silica. Most such substances not only do not need fixation but are not acted upon by fixatives; or, if acted upo...

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confidence: 99%

Principles of biological microtechnique; a study of fixation and dyeing

Baker¹

1958

185

172

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“…Interest in techniques for the prefixation treatment of vertebrate cytological material has been increasing since the recent work of Hughes (9), Hsu (7), Hsu and Pomerat (8), and others. Many agents, often hypotonic saline solutions, have been recommended for this purpose.…”

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Cytological Effects of Prefixation Treatment

Hungerford

DiBerardino

1958

The Journal of Cell Biology

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The effects produced by prefixation treatments on cells in metaphase from 10-day mouse fctuscs and from several embryonic stages of the frog were investigated. The technical value of some of these prctrcatmcnts is noted.Pretreatment with isotonic solutions (both ionic and non-ionic in the case of the mouse, ionic only in the frog) generally produced a similar effect, viz., chromosomal swelling with little effect on the spindlc. A notable exception is provided by frog embryos preceding the ncurula stage; spindle disorganization without chromosomal swelling was produced by pretrcatmcnt in isotonic modified Niu-Twitty solution, containing no divalcnt cations.Pretreatment with hypotonic solutions (both ionic and non-ionic in the case of the mouse, ionic only in the frog) generally produced several major effects, viz., dcspiralization of chromosomes, chromatid separation, and spindle disorganization. The conclusion is drawn from the mouse data that, in order to produce thcse effects, pretreating solutions must bc of low osmotic pressure. Low ionic strength alone (e.g., isotonic sucrose solutions) is not sufficient.As diffcrcntiation of frog embryos progressed, pretreatments either of longer duration or with solutions of increasing degrees of hypotonicity were required to produce comparable intensities of the same effects.Many of the effects on mctaphases produced by hypotonic pretreatment of frog embryos wcrc reversible by subsequent exposure to isotonic solutions.The significance of results presented hcrc is discussed briefly with respect to some current considerations of the macromolccular structure of chromosomes.

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The Haydn Orchestra

Cited by 2 publications

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Principles of biological microtechnique; a study of fixation and dyeing

Principles of biological microtechnique; a study of fixation and dyeing

Cytological Effects of Prefixation Treatment

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