The influence of congo red on the effects of ditiline

Summary In low concentrations (1·10^–6) congo red intensifies the contractions of the isolated m. rectus abdominis produced by ditiline. Higher concentrations (1·10^–4) of congo red depress these contractions. The first effect is probably connected with the depression of cholinesterase, and the second — with the action of the dye on the muscle. The formation of a congo red compound with the quaternary ammonium bases — ditiline (dicholine ester of succinic acid) and curarine (contained in curare), as suggested in pertinent literature, could not be established by means of a spectrographic analysis.Presented by Active Member AMN SSSR V. V. Zakusov     

Picrosirius red: a better polarizing stain

Collagen is a part of the extracellular matrix proteins that form an integral part of the connective tissue stroma. Collagen plays an important role in maintaining the structural and functional integrity of tissue. Due to the arrangement of its fibers, it illustrates the phenomenon of birefringence that is enhanced by special stains like van Gieson and Picrosirius Red. The aims of the present study were to compare the polarizing properties, shelf life and staining intensity of both these connective tissue stains to ascertain which gave better and most cost-effective results. A retrospective study was conducted in the Department of Oral Pathology where histopathologically diagnosed cases of fibroma were selected. Consecutive sections of formalin fixed and paraffin embedded tissues were stained with Picrosirius Red and van Gieson stains, respectively. This staining procedure was repeated on successive sections every 15th day for a period of 6 months. The polarizing property and staining intensity of the new and the previously stained sections along with the shelf life of the staining solutions were simultaneously evaluated and revaluated each time and tabulated. The data obtained was analyzed by using independent t-test and chi-square test. After a period of six months, the polarization intensity and stability of Picrosirius red was found to be better than van Gieson and this could also be appreciated more clearly in the stained sections. The p value was also found to be statistically more significant with Picrosirius Red as compared to van Gieson. Picrosirius Red Stain is not only more stable but also has better polarizing properties, staining intensity, and a longer shelf life as compared to van Gieson.     

Dichroism with congo red. A specific test for amyloid?

Summary Alveolar and young Haversian bone of humans and rats was found to stain with Congo red. Observations in polarized light showed Maltese cross birefringence with green dichroism. The possibility of systemic amyloidosis was rejected.The laminated intratubular bodies in the kidneys in multiple myeloma, the cerebral and prostatic corpora amylacea and pulmonary microliths are also Congo red positive and give a bright green birefringence in polarized light.Dichroism is merely the product of glycoprotein molecules that are disposed in an ordered pattern and that have a great affinity for Congo red and other dyes.The green dichroism that some authors have maintained is a specific characteristic of amyloid is shown by the results reported here not to be a completely reliable index of amyloid.

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Dichroism mit Kongorot. Eine spezifische Probe für Amyloid?

Zusammenfassung Spongiosa und junge Haverssche Osteonen von Menschen und Ratten färben sich mit Kongorot an. Im polarisierten Licht zeigen die Kongorot-positiven Abschnitte einen charakteristischen Farbwechsel mit grüner Doppelbrechung. Die Möglichkeit einer generalisierten Amyloidose war in den Experimenten ausgeschaltet.Corpora amylacea im Nervensystem, in Prostata und Lunge wie die intratubulären lamellären Körper in den Nieren bei Myelom färben sich ebenfalls mit Kongorot an und geben im polarisierten Licht eine stark grün aufleuchtende Doppelfärbung. Diese Ergebnisse lassen darauf schließen, daß die Doppelbrechung mit Grün-Aufleuchten, welche bis dahin als Amyloid-spezifisch angesprochen worden ist, nicht als solche anerkannt werden kann. Das Grün-Aufleuchten bei Kongorot-positiven Substanzen beruht auf der Anwesenheit Glykoproteinmolekülen mit großer Affinität zu Kongorot und bestimmter Textur.

     

Identification of calcium oxalate crystals using alizarin red S stain

Calcium oxalate crystals stain with alizarin red S at a pH of 7.0 but not at a pH of 4.2. In contrast, calcium phosphate and calcium carbonate stain at a pH of both 7.0 and 4.2. This difference allows presumptive identification of calcium oxalate deposits. The identity of calcium oxalate can then be confirmed by its insolubility in 2M acetic acid, since both calcium carbonate and calcium phosphate are soluble. We have applied this procedure for several years and have found it to be a rapid, reliable, and technically simple procedure for distinguishing calcium oxalate from other calcium deposits.     

Factors affecting haemolysin production and congo red binding in Salmonella enterica serovar Typhimurium DT 98

Differences in haemolysin expression were observed in a strain of Salmonella enterica serovar Typhimurium definitive phage type (DT) 98 cultured under various conditions. Haemolysin expression was optimal in cultures grown micro-aerobically. The zones of haemolysis were wider after longer periods of incubation. Haemolysin production varied after growth in the following media (greatest to least): brain heart infusion (BHI) broth > nutrient broth (NB)>trypticase soy broth (TSB)> M-9 glucose medium. Haemolysin production correlated directly with Congo red binding in nutrient broth. On Congo red blood agar, colonies were smaller, with dark centres and wider zones of haemolysis. Culture-cell-free haemolysin activity was higher, but cell-bound haemolysin activity was very low in growth medium supplemented with Congo red. Boiled tea extract at 25% v/v (of 25% w/v tea infusion) in PBS and nutrient broth was bactericidal to S. Typhimurium DT 98. The addition of boiled tea extract to growth medium inhibited haemolysin production by S. Typhimurium DT 98 at higher concentrations (6-12.5% v/v) but stimulated haemolysin production at lower concentrations (1.5-3% v/v). The pre-treatment of bacterial cell suspensions with lower concentrations of tea extract (1.5-3% v/v) also altered the Congo red binding, which showed an inverse correlation in nutrient broth.     

Victoria blue-nuclear fast red stain for HBs antigen detection in paraffin section

Hepatitis B surface antigen, in paraffin embedded sections, can be stained by victoria blue and recognized easily against the background, including the cytoplasm and nucleus, stained by nuclear fast red. This new staining method has many merits such as easy staining procedure, long stability of dye solution, negative stainability of ordinary bile pigment, etc., and seems to be quite useful for routine as well as research works in hepatology.     

The use of the dye neutral red as a specific, non-toxic, intra-vital stain of islets of Langerhans

The development of improved methods of islet isolation from the pancreas is hampered by difficulty in identification of islets. A method described by Bensley in 1911 uses neutral red to stain the islets selectively. In the present study the method has been simplified and selective staining of islets in the rat, dog and pig demonstrated by use of light and electron microscopy. Staining of islets with neutral red does not appear to affect their viability as judged by insulin secretion and transplantation in rats.     

A 101-kilodalton heme-binding protein associated with congo red binding and virulence of Shigella flexneri and enteroinvasive Escherichia coli strains.

The ability of Shigella flexneri to bind Congo red or hemin is associated with virulence. A 101-kilodalton (kDa) protein responsible for this phenotype (Crb+) in S. flexneri was identified by a tetramethylbenzidine staining procedure which detects heme-protein complexes in polyacrylamide gels. Labeling of cell-surface polypeptides with 125I revealed that the 101-kDa heme-binding protein is expressed on the cell surface. Expression of the protein was regulated by growth temperature and was found to be encoded by the large virulence plasmid of S. flexneri. Deletion mutants and a Tn5 insertion mutant which were negative for Congo red binding (Crb-) did not express the 101-kDa protein. Enteroinvasive Escherichia coli strains that were Crb+, and whose plasmids shared homology with the S. flexneri virulence plasmid, also expressed the 101-kDa protein. Expression of the protein in S. flexneri and enteroinvasive E. coli correlated with the presence of a 9.2-kilobase EcoRI fragment of these plasmids.     

The use of the dye neutral red as a specific,non-toxic,intra-vital stain of islets of Langerhans.

The development of improved methods of islet isolation from the pancreas is hampered by difficulty in identification of islets. A method described by Bensley in 1911 uses neutral red to stain the islets selectively. In the present study the method has been simplified and selective staining of islets in the rat, dog and pig demonstrated by use of light and electron microscopy. Staining of islets with neutral red does not appear to affect their viability as judged by insulin secretion and transplantation in rats.     

Use of Nile red stain in the detection of cholesteryl ester accumulation in acid lipase-deficient fibroblasts

The fluorescent hydrophobic probe Nile red was used to distinguish between normal human fibroblasts and fibroblasts from individuals with a genetic deficiency in lysosomal acid lipase activity (Wolman's disease and cholesteryl ester storage disease). The fluorescence of Nile red-stained cultured mutant cells, indicative of neutral lipid accumulation, was intense when compared microscopically with normal fibroblasts. The cholesteryl ester accumulation in the acid lipase-deficient fibroblasts was demonstrated qualitatively and quantitatively when cellular lipid extracts were subjected to thin-layer chromatography, followed by Nile red plate treatment and fluorescence spectrometry scanning. These results demonstrate the utility of the Nile red stain to document cellular lipid overloading. The techniques are simple to perform and can effectively supplement the standard enzymatic analysis used in the diagnosis of acid lipase deficiency.