Sex Chromatin Frequency in the Avian Aminon

Conflicting results have been reported on the incidence of sexchromatin in avian cells. In this study the sex chromatin frequenciesare explored in the ammotic cells from two .Leghorn varietiesof domestic fowl, a species which is reported to possess anheterochromatic and late leplicating W sex chromosome. The incidenceof sex chromatin was also examined in the ammotic epitheliumof the Japanese quail throughout the incubation period. Thisspecies of quail possesses a W sex chromosome that is euchromaticat metaphase When the sex chromatin frequencies in the domestic fowl werecompared with the gonadal sex of the embryos, a nuclear sexualdimorphism was apparent with the high frequencies correspondingto embryos of the female sex. No such nuclear sexual dimorphismwas found in the quail, both male and female embryos had approximatelythe same incidence of sex chromatin in their ammotic cells These findings are interpreted in support of the idea that thecytological entity identified as sex chiomatin in the domesticfowl represents the W sex chromosome in the interphase nucleus     

The Peracetic-Orcein-Halmi Stain: A Stain for Connective Tissues

A selective stain useful for the study of connective tissues is described. The stain demonstrates elastic and oxytalan fibers as well as fibrils in mucous connective tissues previously undescribed. Reticular fibers are not stained. The stain may be used on sections that have been fresh frozen or fixed in formalin or ethanol. Sections are deparaffinized, washed in absolute ethanol, oxidized in peracetic acid 30 min, washed in running water, stained in Taenzer-Unna orcein 15 min, 37°C, differentiated in 70% ethanol, washed in running water, stained in Lillie-Mayer alum hematoxylin 4 min, blued in running water, and counterstained 20 sec in a modified Halmi mixture of 100 ml distilled water, 0.2 gm light green SF, 1.0 gm orange G, 0.5 gm phosphotungstic acid and 1.0 ml glacial acetic acid. Sections are rinsed briefly in 0.2% acetic acid in 95% ethanol, dehydrated and mounted.     

A One-Solution Stain for Spermatozoa

Fresh semen is allowed to liquefy 30-60 minutes and thin, even smears of it made on clean slides or cover glasses. The smears are fixed 3 minutes with an equal-parts mixture of alcohol and ether, then air dried. They are stained 5-7 minutes in an aqueous solution made by mixing 2 volumes of 5% aniline blue (water soluble), 1 volume of 5% eosin B and 1 volume of 1% phenol. Staining at 40-60°C. is recommended. After staining, the smears are washed with distilled water, air dried and mounted in balsam or synthetic resin. The method was used on over 2000 samples of dog semen and some human specimens. Good preservation and differentiation of cytological structures was obtained uniformly, but tests were not made with other species.     

A Controllable Differential Stain for the Hypophysis by Adaptation of the Mallory Triple Stain

A selective and controllable staining method for the hypophysis has been developed with rat material, using Mallory's triple stain as a basis.

Fix in Zenker neutral formol for 6 hours. Longer fixation is undesirable. Transfer to 30% alcohol plus a few drops of a saturated solution of I₂ in aqueous KI over night. Gradually complete dehydration and clear in cedar oil. Infiltrate with a paraffin mixture (paraffin, rubber-paraffin, bayberry wax and beeswax). Section 3-Sμ. Hydrate to distilled water, placing a few drops of a KI-I₂ solution in the 50% alcohol. Stain in 1% acid fuchsia for 30 minutes. Rinse, and differentiate in a weak NH₄OH solution (one drop 28% NH₄OH to 200 cc. HOH). When differentiation is complete, transfer to a 0.5% phosphomolybdic acid solution for 3 minutes, after first stopping the differentiation with a 0.1% HC1 solution and then rinsing with distilled water. Stain for one hour in a solution of: 1% anilin blue, water soluble, 2% orange 6, and 1% phosphomolybdic acid. Rinse in distilled water plus a few cubic centimeters of the stain. Differentiate in 95% alcohol, transfer to absolute alcohol and clear in a mixture of 30% oil of cedar, 40% oil of thyme, 15% absolute alcohol and 15% xylene. Finally, transfer to xylene and mount.     

A Simple Technique for Sex Chromatin Analysis in Amniotic Cells of Mouse and Rat Embryos

A simple technique has been developed for sex chromatin analysis in the amniotic membrane of rodent embryos. This technique combines the use of 60% acetic acid as a fixative and a carbol fuchsia stain. This technique may be useful for quick sex diagnosis of rodent embryos at midgestation for various purposes in experimental embryology.     

A Differential Stain for Nucleic Acids

An easily used trichrome stain consisting of orange G, methyl green, and toluidine blue is proposed as a method of differentiating desoxyribonucleic acid (DNA) and ribonucleic acid (RNA) in cells. Carnoy's acetic-alcohol is the fixative of choice, though cold acetone is also satisfactory. Photomicrographs taken with ultraviolet and visible light show that the structures containing nucleic acid are exactly those which stain with methyl green and toluidine blue. Studies with nucleases and extraction of nucleic acids with cold and hot perchloric acid further indicate a specificityy of the dyes for DNA and RNA. Present experiments are directed toward using the stain for quantitative estimation of the nucleic acids.     

A Tri-Basic-Dye Stain for Nerve Cells

A new staining method has been developed for the study of nerve cells and Nissl granules which combines three basic dyes, cresylecht violet, toluidine blue and thionin. The use of this tri-basic-dye stain results in finished preparations that are critically stained and permanent. Paraffin sections (4 μ sections preferably) are mounted on slides by the starch medium, deparaffinized and stained by the tribasic staining solution. After differentiation in acidified distilled water, sections are dehydrated, returned to stain solution and again dehydrated, then cleared and mounted in Clarite. Various vertebrate material including normal and pathological human tissues have been stained with this triple dye solution. Especially for pathological material, re-immersion of slides in the staining and 80% alcohol solutions before mounting, differentially intensifies the staining reaction. Fixatives used were 10% formalin, 95% alcohol, Bouin and formalin-Bouin (10% formalin followed by Bouin).     

A Trichrome Stain for Insect Material

Deparaffinized insect sections are brought down to water and overstained in a 0.1% solution of azocarmine G in 1% acetic acid. They are then destained in a saturated solution of orange G until the azocarmine G is removed from the endocuticle and the latter is colored pale yellow. After washing, the sections are transferred to a 5.0 % solution of phosphotungstic acid in water for 3 min. They are then rinsed in distilled water and stained in a 0.1% solution of methyl green in 1% acetic acid until the endocuticle is green. Differentiation is done in 2 changes of 95% alcohol. The sections are then dehydrated either in absolute alcohol or dioxane, cleared in a mixture of “camsal”, eucalyptol, dioxane, and paraldehyde (1:2:2:1), and mounted in Mohr and Wehrle's medium, a mountant of the Euparal type.     

A Metachromatic Stain for Neural Tissue

The need for rapid histological feedback on neural tissue is ever present. Although there are several stains which can be readily used for staining either cell bodies or fiber tracts, adequate contrasting stains which are both rapid and easy to apply are not generally available. In 1936 Chang presented a technique for whole brains utilizing the metachromatic properties of thionin. Unfortunately this procedure was very time consuming. For the last several years we have worked with several variations of this stain and have found that thionin can be reliably used as a polychrome stain for sections of neural tissue obtained from a freezing microtome.     

A Safe Spore Stain for Class Use

In looking for an efficient method of pre-treating bacterial spores for staining with carbol fuchsin, the author found that the ammonia in Lagerberg's formula and the chromic acid in Moeller's formula were both fairly effective in increasing permeability. Combining the two proved highly successful; and the following method has been used for four years by classes of beginners in the study of spore-formers isolated from soil by the students.

Cover the heat-fixed smear with five percent chromic acid and after thirty seconds add twice the amount of concentrated ammonia to the acid. After two minutes rinse and steam with carbol fuchsin for two or three minutes. Rinse, destain with one percent sulphuric acid for fifteen to thirty seconds, rinse again and flood slide with tap water. Add to this a few drops of Loeffler's methylene blue and allow to counter-stain for ten to thirty seconds. Rinse, blot, dry and examine. If instructions are followed the results are always good.     

A Polychromatic Stain for Use in Parasitology

In sensory systems, insight into synaptic arrangements on cells of known physiological response properties has helped our understanding of the structural basis for these properties. To carry out these types of studies, however, synaptic types in the region of interest must be defined. Unfortunately, defining synaptic types in the brainstem has proved to be a challenging enterprise. Our study was done to classify synapses in the gustatory part of the nucleus solitarius using objective quantitative criteria and a cluster analysis procedure. Cluster analysis allows classification of a population of objects, such as synaptic terminals, into groups that exhibit similar characteristics. Six terminal types were identified using cluster analysis and subsequent analyses of variance and post hoc tests. Unlike classification schemes used for the cerebral cortex, where synaptic apposition density thickness and shape of vesicles is useful (Gray's Type I and II synapses), the concentration of vesicles in a terminal was a more useful measurement with which to classify terminals in the nucleus solitarius. To validate that vesicle density (vesicles/μm²) is a useful defining characteristic to classify terminals in the nucleus solitarius, terminals of a known type were used. GABAergic terminals were identified using postembedding immunohistochemical techniques, and their vesicle density was determined. GABAergic terminals fall into the range of two of the terminal types defined by the cluster analysis and, based on vesicle density, two types of GABAergic terminals were identified. We conclude that vesicle density is a helpful means to identify synapses in this brainstem nucleus.     

Kallichrome: A New Stain for Erythroblasts

Using the obscure dye kallichrome, erythroblasts at all stages of maturation demonstrated intense yellow to yellow-brown staining of both nucleus and cytoplasm. Staining of this type was not observed in other types of normal or pathological marrow cells. As such, kallichrome may be a valuable stain for identification of erythroblasts and their distinction from other types of blood cells.     

A New Stain for Pollen Fertility Studies

The juice from the berries of Cocculus hirsutum was extracted and used for pollen fertility studies in various crops. Two stains were prepared: P. H. Ramanjini (PHR) stain and modified PHR stain. The modified PHR stain contains lactic acid and produces the best staining differentiation. The intensity of the staining was dependent on the thickness of the pollen cell walls, hence PHR stain is recommended for thick walled pollen grains and the modified PHR stain for pollen with relatively thin walls. The preparation of both the stains are very simple, quick and inexpensive.