Aldehyde bisulfite-toluidine blue (ABT) staining as a topo-optical reaction for demonstration of linear order of vicinal OH groups in biological structures

Fluorescence, aggregation properties and FT-IR microspectroscopy of elastin and collagen fibers

Histological and histochemical observations support the hypothesis that collagen fibers can link to elastic fibers. However, the resulting organization of elastin and collagen type complexes and differences between these materials in terms of macromolecular orientation and frequencies of their chemical vibrational groups have not yet been solved. This study aimed to investigate the macromolecular organization of pure elastin, collagen type I and elastin-collagen complexes using polarized light DIC-microscopy. Additionally, differences and similarities between pure elastin and collagen bundles (CB) were investigated by Fourier transform-infrared (FT-IR) microspectroscopy. Although elastin exhibited a faint birefringence, the elastin-collagen complex aggregates formed in solution exhibited a deep birefringence and formation of an ordered-supramolecular complex typical of collagen chiral structure. The FT-IR study revealed elastin and CB peptide NH groups involved in different types of H-bonding. More energy is absorbed in the vibrational transitions corresponding to CH, CH2 and CH3 groups (probably associated with the hydrophobicity demonstrated by 8-anilino-1-naphtalene sulfonic acid sodium salt [ANS] fluorescence), and to νCN, δNH and ωCH2 groups of elastin compared to CB. It is assumed that the α-helix contribution to the pure elastin amide I profile is 46.8%, whereas that of the B-sheet is 20% and that unordered structures contribute to the remaining percentage. An FT-IR profile library reveals that the elastin signature within the 1360-1189cm(-1) spectral range resembles that of Conex-Toray aramid fibers.

Polarization optical-histochemical characterization and supramolecular structure of carbohydrate fibrils

Topo-optical staining reactions were used to investigate the structures of bacterial cellulose, insect chitosan and alginic acid from brown algae. Polysaccharide complexes, glycosaminoglycans and sulfate groups were presented and demonstrated selectively. Chitosan and alginic acid are structurally similar to glycosaminoglycans (GAGs), which are constituents of human amyloid fibrils. The staining sequences shown can be used as reliable methods for histochemistry with light and polarization microscopy. They will help to clarify the complex protein-polysaccharide structure of amyloid fibrils.

Confocal fluorescence detected linear dichroism imaging of isolated human amyloid fibrils. Role of supercoiling

Amyloids are highly organized insoluble protein aggregates that are associated with a large variety of degenerative diseases. In this work, we investigated the anisotropic architecture of isolated human amyloid samples stained with Congo Red. This was performed by fluorescence detected linear dichroism (FDLD) imaging in a laser scanning confocal microscope that was equipped with a differential polarization attachment using high frequency modulation of the polarization state of the laser beam and a demodulation circuit. Two- and three-dimensional FDLD images of amyloids provided information on the orientation of the electric transition dipoles of the intercalated Congo Red molecules with unprecedented precision and spatial resolution. We show that, in accordance with linear dichroism imaging (Jin et al. Proc Natl Acad Sci USA 100:15294, 2003), amyloids exhibit strong anisotropy with preferential orientation of the dye molecules along the fibrils; estimations on the orientation angle, of around 45°, are given using a model calculation which takes into account the helical organization of the filaments and fibrils. Our data also show that FDLD images display large inhomogeneities, high local values with alternating signs and, in some regions, well identifiable µm-sized periodicities. These features of the anisotropic architecture are accounted for by supercoiling of helically organized amyloid fibrils.

Electron microscopic demonstration of Romhányi's aldehyde-bisulphite-toluidine blue (ABT)-topo-optical staining reaction

Romhányi's aldehyde-bisulphite-toluidine blue (ABT) topo-optical reaction was checked electron microscopically. The reaction product was found localized on the sarcolemma membrane and intercalated disc. The findings suggest that the topo-optical ABT-reaction is suitable for molecular analysis. In addition to confirming the electron microscopic suitability of the ABT-reaction it has also offered ultrastructural evidence for the reliability of the topo-optical method.

Topo-optical reactions for the identification of O-acyl sugars in amyloid deposits

The aldehyde bisulfite toluidine blue (ABT) reaction with former saponification (KOH-ABT) and periodic acid-borohydride reduction-saponification (PB-KOH-ABT) were applied to sections of human amyloid deposits in the respiratory tract. The saponification-induced increase in ABT-reactivity was confined to the presence of O-acyl sugars associated with the amyloid fibrils. The anisotropic and metachromatic effect in the ABT and KOH-ABT reaction was reduced in the corresponding PB-KOH-ABT reaction, a difference attributed to the removal of staining due to neutral carbohydrate residues. Since the periodic acid-borohydride reduction abolishes all pre-existing ABT-reactivity of neutral sugar vicinal diols, the isolated KOH-effect could be shown using the PB-KOH-ABT reaction. By application of this sequence, the problem identifying small quantities of O-acyl sugars was solved. It is suggested that the KOH-effect depends upon the removal of O-acyl substituents located on the polyhydroxy side chain (C7, C8, C9) of sialic acid residues. An advantage of such topo-optical reactions over biochemical techniques is the exact localization of O-acyl sugars in tissue sites. By means of the KOH-ABT and PB-KOH-ABT reactions we have demonstrated, for the first time, that O-acyl sugars occur within amyloid deposits.

The relevance of the aldehyde bisulfite toluidine blue reaction and its variants in the submicroscopic carbohydrate research

Carbohydrates are chemical compounds that contain only oxygen, hydrogen and carbon. They are classified by their number of sugar units: monosaccharides (such as glucose and fructose), and disaccharides (such as sucrose and lactose) are simple carbohydrates; oligosaccharides and polysaccharides (such as starch, glycogen and cellulose) are complex carbohydrates. Carbohydrates play a crucial role in diverse biological systems [Hricovín M. Structural aspects of carbohydrates and the relation with their biological properties. Curr Med Chem 2004;11:2565-83]. According to Roseman [Sugars of the cell membrane. In: Weissmann G, Clairborn E, editors. Cell membranes. Biochemistry, Cell Biology, Pathology. New York: H. P. Publ. Co; 1975. p. 55-64], two classes of glycoproteins are described. Free glycoproteins are localised in the surface coat of the membranes and form a thick mobile layer, without any association to the membrane itself. Functionally, however, they are located in a close association with the membrane (e.g. in the duodenal mucosa). The other group consists of the membrane glycoproteins, which are integral to the membranes and are located in the outer layer. The oligosaccharide chains are bound to the N-terminal part of proteins, and are situated in the hydrophilic zone. Glycoproteins have diverse functions. They are important in specific receptor functions, in immunological cell destruction and play a significant role in reactions with lectins, antibodies, as well as in cell association and mutual recognition of the cells. This paper focuses on aspects of a summary of polarisation optical investigations and biological functions of the following three groups of carbohydrates: oligosaccharides, glycoproteins and glycosaminoglycans.

Polarization optical analysis of the surface structures of various fungi

Vicinal hydroxyl groups of the sugar compounds sialic acid and 9-O-acyl sialic acid can be visualised for polarization optical analysis on the surface of different fungi using several topo-optical reactions. We investigated the presence of these molecules in cultures of Cryptococcus neoformans (heterogeneous form), Saccharomyces cerevisiae, Candida albicans, Candida glabrata, Candida krusei and Candida tropicalis by topo-optical reactions. Additionally, we examined brain and stomach tissues of patients with infections by C. neoformans and C. albicans, respectively. The results suggest a highly fashioned orientation of the sugar chains on the fungal surface. Terminal sialic- and O-acyl sialic acid residues are permanently present and orientated in a highly specific way in the cell wall of fungi. Based on the polarization optical analysis after the ABT-r (anisotropic PAS-r), the linear oriented hydroxyl groups of the sugar molecules are localized either perpendicular or parallel to the surface coat, depending on the species. According to the orientation of the vicinal hydroxyl groups, the oligosaccharide chains are orientated vertically. The capsule of the heterogeneous form of C. neoformans presented an especially strong metachromatic reaction and anisotropy. It is especially remarkable that the sterical orientation of sugar chains, and the terminal sialic acid and 9-O-acyl sialic acid molecules, was opposite in the inner and outer layer of the capsule.

Topo-optical investigations on the surface of bacterial cells during the phagocytosis of Klebsiella pneumoniae in mouse

Polarisation optical methods provide the means to perform sub-microscopic investigations on structures containing spatially highly ordered molecules, for example the cell envelope of prokaryotic cells. Such structures can evoke birefringence, which can be enhanced or modified by different dyes or reagents, thus providing the possibility of a more specific investigation of the composition and structure of bacterial surface compounds. Klebsiella pneumoniae synthesises sterically different carbohydrate-rich structures, including those of the outermost capsular polysaccharide, the polysaccharide somatic antigen of the lipopolysaccharide molecule and the peptidoglycan layer of the cell wall. In the study reported here, the nature and intensity of topo-optical activity of these structures was analysed using the aldehyde-bisulphite-toluidine blue reaction, sialic acid topo-optical reactions and chlorpromazine-eosin charge transfer reactions. Furthermore, a mouse intraperitoneal model was used to analyse alterations in topo-optical characteristics of bacteria during phagocytosis. Both encapsulated and non-encapsulated bacterial cells changed their original pattern and orientation of birefringence after being phagocytosed.

Identification of elastic fibers and lamellae in porcine pericardium and aorta by confocal, fluorescence and polarized light microscopy

Pericardial connective tissue has been used to construct bioprostheses to repair various types of injuries, including aortic wall repairs. The arrangement and the distribution of elastic and collagen staple fibers are related directly to the biomechanical properties of the tissue and thus determine the choice tissue for the construction of bioprostheses. Although elastic fibers can be visualized using several histochemical methods, the specificity and mechanism of binding involved remain to be clarified. In this work, we compared the elastic net of the porcine pericardial matrix with that of the aortic wall using 1-anilino-8-naphthalene sulfonate (ANS) and dansyl chloride (DCl) as fluorescent probes and the permanganate-bisulfite-toluidine (PBT) method. Polarized light and fluorescence microscopy were simultaneously used to analyze the tissues. Some samples also were examined using confocal microscopy. Aorta and pericardium treated with ANS and DCl showed elastic fibers and lamellae with an intense blue fluorescence. When stained with the PBT method, the aortic elastic lamellae were clearly metachromatic and, under polarized light, they showed a greenish birefringence. DCl provided clearer fluorescent labelling of elastic fibers when examined using confocal microscopy.

Topooptical investigations and enzymatic digestions on tissue-isolated amyloid fibrils

Chemical and biochemical analysis of isolated amyloid fibrils reveals the presence of different classes of proteins which are often related to distinct clinical forms of amyloidosis and are useful to classify the amyloid deposits. In this study, enzymatic digestions using hyaluronidase, chondroitinase AC and B, neuraminidase, and chemical extractions using mild acid hydrolysis with hydrochloric and sulfuric acid, were used to control the specificity of various topooptical reactions. The disappearance of intense staining after these extraction methods indicates that tissue-isolated amyloid fibrils contain sialic acids and glycosaminoglycans (GAGs). We conclude that topooptical reactions are the most sensitive methods to detect conformational changes in the non-fibrillar component of amyloid deposits and tissue-isolated amyloid fibrils.

Case report: amyloid tumors in a case of non-secretory multiple myeloma

Multiple myeloma (MM) is a neoplastic disorder characterized by proliferation of a single clone of plasma cells derived from B cells, which proliferates in the bone marrow and frequently invades the adjacent bone, producing skeletal destruction that results in bone pain and fractures. Patients with MM can furthermore present with anemia, hypercalcemia and renal failure. Non-secretory multiple myeloma (NSMM) is characterized by the absence of a monoclonal (M) protein in both the serum and urine. The reported incidence is 1-5% of all multiple myeloma cases. Development of amyloid tumors in NSMM has been described in the literature only occasionally. The clinical features of a 49-year-old female patient with NSMM and amyloid tumors in the breast, lung and rib are presented in this report. Conventional histology, Congo red staining with and without potassium permanganate pretreatment, aldehyde bisulfite-toluidine blue (ABT) reaction, sialic acid specific topo-optical reaction, toluidine blue topo-optical reaction as well as immunohistochemistry were performed. An attempt is made to explain the lack of monoclonal immunoglobulins in the serum and urine, although extensive organ amyloidosis of AL type (kappa-light chains) has been found. It is assumed that the plasmocytic plasma cells possess an excretory mechanism, which allows the pathologic immunoglobulins to be secreted either as amyloid proteins polymerizing into amyloid fibrils, or as immunoglobulin fragments that are subject to degradation as soon as they are excreted out of the tumor cell. In this paper, we review the occurrence of amyloid tumors in non-secretory multiple myeloma and, in a single case report, we confirm the existence of carbohydrate residues, including sialic acids and sulfated GAGs, in amyloid deposits.

Topo-optical visualization reactions of carbohydrate-containing amyloid deposits in the respiratory tract

Staining with Congo red according to is the most commonly used method for the demonstration of amyloid, but structures other than amyloid can give false-positive results. To overcome this problem, introduced an aqueous Congo red staining with gum arabic as the mounting medium, which we have used in this and previous publications. Most histochemical studies on amyloid deposits to date have concentrated on conventional methods including staining with thioflavine, sirius red, alcian blue, methyl and crystal violet. In this study, we used topo-optical reactions with thiazine dyes on both the light and polarization microscopic level to establish the structure, distribution and location of carbohydrate components that occur within amyloid deposits, especially in the respiratory tract. Topo-optical staining reactions for the qualitative analysis of carbohydrate components in amyloid deposits included (1) reactions that identify the carbohydrate residues, (2) reactions that detect sialic acids and, (3) methods that visualize glycosaminoglycans. In conclusion, a comparison of consecutive serial sections stained with Congo red, aldehyde bisulfite toluidine blue reaction, sialic acid-specific topo-optical reaction, toluidine blue topo-optical reaction and chemically intensified basophilic reaction showed correlative staining patterns and anisotropic effects, corresponding to a close pathomorphological relationship between amyloid fibrils, periodate reactive carbohydrates, including sialic acids, and glycosaminoglycans.

Histochemical and topo-optical investigations on tissue-isolated and in vitro amyloid fibrils

An improved microscopic slide preparation for staining of tissue-isolated and in vitro amyloid fibrils is described in detail. Specimens were prepared by slow drying of an amyloid fibril suspension on aminoalkyl-silanised glass slides underneath a coverglass. The purpose of this method is to obtain microscopically visible fibers. Polarization microscopy was performed on unstained fibers in different embedding media, on fibers stained with Congo red, toluidine blue, 1,9-dimethylmethylene blue, anisotropic PAS reaction and Sudan black. Results were identical in 8 tissue-isolated amyloid fibril preparations. The refractive index of amyloid was about 1.5, as expected for protein fibrils. Congo red-stained fibrils showed yellow or blue-green polarization colors, while staining with toluidine blue or 1,9-dimethylmethylene blue induced green or orange polarization colors. The latter dyes stained the fibrils even in buffers with low pH or high ionic strength, pointing to strong acidic groups like sulphates in amyloid. The anisotropic PAS reaction for selective demonstration of periodate reactive carbohydrates in tissue-isolated amyloid fibrils was positive. Thus, linearly ordered acidic groups and carbohydrate residues could be detected for the first time in tissue-isolated amyloid fibrils using an improved technique for microscopic slide preparation on one side and topo-optical reactions on the other.

Studies of bronchoalveolar lavage in sudden infant death syndrome: a clinical-pathological study

The incidence of sudden infant death syndrome (SIDS) in Hungary was 0.3 per 1000 live births in 1992. We investigated bronchoalveolar lavage (BAL) of eight infants with SIDS, using bacteriological, light and electron microscopic methods to collect data about the role of respiratory inflammations in SIDS children and to determine the usefulness of the BAL technique. Findings are discussed.

Non-fibrous zeolite induced experimental pneumoconiosis in rats

A study was made on the pulmonary pathological reactions after intratracheal introduction of non-fibrous zeolite into CFY rats in long-term sequential investigations (1st week; 1st, 3rd, 6th months and 1st year). After treatment at the end of the 1st week non-specific confluating bronchopneumonia followed by a storage type reaction developed at the end of the 1st month. In the later periods in addition to storage character mild pulmonary fibrosis has been observed. At the end of the 1st year, transmission electron microscopy and X-ray microanalysis verified that aluminium and silicon ratio in zeolite storaged in the macrophages of the lungs was the same as found in natural zeolite (1:6). In the lungs of 3 animals atypical hyperplasia developed; therefore an in vivo study of the carcinogenic effect of non-fibrous zeolite seemed justified.

Immunofluorescence demonstration of digoxin in human myocardial tissue and isolated rat cardiac myocytes with monoclonal antibodies

The aim of the present investigation was to identify the morphological correlates of digoxin binding sites in human heart muscle tissue and isolated viable rat heart myocytes. Cardiac glycoside linked to myocardial cells was demonstrated by monoclonal digoxin specific antibody and by FITC-conjugated anti-mouse immunoglobin serum. This versatile immunofluorescence method can be used in diagnostic and experimental studies of cardiac glycoside binding.

Periodic acid-Schiff-alcian blue: a method for the differential staining of glycoproteins

The staining mechanism underlying the periodic acid-Schiff (PAS)-Alcian Blue (AB) sequence has been investigated using a variety of glycoprotein-containing tissues from different organs of the monkey, rat and mouse. The results obtained suggest that reactive carbohydrates contain at least three types of chemical end-groups found in neutral and acidic glycoproteins: (1) PA-engendered aldehyde groups coloured magenta by the Schiff reagent; (2) PA-engendered aldehyde groups coloured blue bisulphite-AB; and (3) naturally occurring acidic (carboxyl and/or sulphate) groups coloured blue by AB only. The PAS-AB sequence showed heterogeneity of glycoprotein structures in the conjunctiva and the duodenal goblet cells. Thus, the PAS-AB sequence is not the simple reverse sequence of AB-PAS but has its own definite and unique staining selectivity and can hence be used as a reliable method for the histochemistry of glycoproteins at the light microscope level.

The variation of Romhányi's aldehyde-bisulfite-toluidine blue (ABT)-reaction: the aldehyde-bisulfite-1.9-dimethyl methylene blue (ABD)- and sialic acid specific topo-optical reaction

The Aldehyde-Bisulfite-1.9-Dimethyl Methylene Blue reaction is a variant of Romhányi's Aldehyde-Bisulfite Toluidine Blue (ABT) reaction. The ABD reaction is also a selective topo-optical staining reaction of the vicinal (glycol) OH-groups in complex carbohydrates. According to polarization optical analysis, after the ABD-reaction we have found the oriented micellar textur of the glycoproteins in the microvillous layer of the human duodenum and jejunum. By means of the sialic-acid-specific topo-optical reaction, we have demonstrated that the sialic acid is present in an ordered form and is evenly distributed in the microvillous surface layer of duodenum and jejunum.

Induced precipitation of calcium-oxalate crystals and its prevention in laboratory animals

Induced precipitation of Ca-oxalate crystals and the possibility of its prevention were studied in dogs. In the first phase of the experiments precipitation of Ca-oxalate crystals in canine renal tubules was induced by intraperitoneal administration of Na-glyoxylate. Preventive medication (lipoic acid, vitamin B1, Milurit), applied in the second phase, resulted in a significant depression of induced precipitation. The successful experiments serve as a basis for clinical research aimed at a preventive medication of recurrent Ca-oxalate stone formation.

Polarized light microscopy in the study of the molecular structure of collagen and reticulin

Although collagen structure has been studied by polarized light microscopy since the early 19th century and continued since, modern studies and reviews failed to correlate the conclusions based on data obtained by the techniques with those of polarized light microscopy. Collagen I is intensely positively birefringent in respect to length of the fibres; the positive intrinsic birefringence indicates a quasi-crystalline alignment parallel to the fibre and molecule axis of the amino acid residues of the polypeptide chains. This would not have been compatible with a helical structure but has been achieved by similar tilt angles and opposite directions of the coiling and supercoiling. Birefringence characteristics of collagen are also affected by chemical treatments, extractions and staining procedures. Attachment of chemical groups to the anionic charges present on the surface of collagen molecules results in increased positive birefringence in the case of bipolar molecules attached to two or more anionic residues. Unipolar attachment to the same groups, or to the cationic groups of the associated proteoglycans, as well as sulfation or acetylation of hydroxyls of the protein and/or the carbohydrate, reduced or reversed the sign of birefringence. Increased birefringence caused by stretching cannot be due to intramolecular events and is caused by intermolecular changes. The same applies to changes in collagen during aging. Reticulin is a group of different substances which mostly contain collagen III. The pliability and deformability of this collagen is related to its weakly negative birefringence due to large side chains and presence of different and greater amounts of interstitial proteoglycans and other molecules. The so-called reticulin of healing wounds differs in its constitution from other reticulins but is also rich in intermolecular carbohydrate components.

Polarization optical analysis of blood cell membranes

The present study deals with investigations of membrane structure using polarization topo-optical reactions. Polarization microscopy is a special field of biological submicroscopic morphology. It represents a powerful tool well able to reveal the features of organization of biological structures, and the regularity of macromolecules building cells and tissues - properties that cannot directly be studied by other approaches to complex biological systems. Only in "pure" systems can X-ray diffraction, or the analysis of circular dichroism and the dispersion of optical rotability provide data equivalent to those obtained by polarization microscopy in complex systems. One of the main drawbacks of molecular biology is that most information is relevant to isolated, purified particles or macromolecules. Thus, no conclusions can be drawn concerning the original arrangement of molecules. The gap between biochemical-biophysical and morphological approaches to molecular arrangement in complex structures is bridged by the polarization optical technique. As was pointed out in the introduction, polarization microscopy became a routine biological research method following the pioneering work of Romhányi. His enlightening topo-optical reactions (Romhányi 1960, 1963, 1966) were based on the oriented dye binding of the original charge carriers of regularly arranged tissue constituents. The second group of Romhányi's topo-optical reactions comprised procedures such as sulfation (Romhányi et al. 1973, 1974), the aldehyde-bisulfite-toluidine blue (ABT) reaction (Romhányi et al. 1974, 1975), the permanganate-bisulfite-toluidine blue (PBT) reaction (Fischer 1979, 1979a), and the sialic acid-specific reaction (Makovitzky 1980) all of which operate with induced dye-binding groups; i.e. dye-binding moieties on biological macromolecules are produced by specific chemical reactions.

Comparative topo-optical investigation of cardiac glycoside localization

The aldehyde-bisulfite-toluidine blue (ABT) reaction is a selective topo-optical test of vicinal-OH and amino-OH groups. The localization of cardiac glycoside was investigated morphologically. After digoxin the sarcolemma membranes, capillaries and sinus node showed strong basophilia and negative birefringence. The topo-optical reaction are useful for the histopathological examination. The new method gives the possibility to the digoxin intoxication with a high specificity.

Comparative histopathological and biochemical analysis of early stages of exposure to non-silicogenic aluminium silicate- and strongly silicogenic quartz-dust in rats

One group of male CFY rats was given bentonite with high aluminium silicate content, the other group was given quartz dust, intratracheally. It has been stated that between 12-72 hours after the dust-exposure, the histological reactions developing upon the effect of non-silicogenic bentonite and silicogenic quartz are identical. Similarly in both groups lipid and phospholipid content of the lung shows a slight increase; the composition of phospholipids does not alter due to the effect of the two dusts. Between 12-72 hours after the exposure to both dusts the inflammatory response characterizing the histological reaction consists mainly of leukocytes; while between 48-72 hours macrophages appear in large numbers. The dust particles are swallowed both by leukocytes and macrophages. The confluating bronchopneumonia developed at the end of the 72nd hour is characterized by necrosis. Ninety days after exposure, bentonite causes storage-focal tissue reaction and quartz produces progressive pulmonary fibrosis; due to the effect of quartz, the lipid and phospholipid content of the lung significantly increases, the ratio of phospholipid fractions alters; bentonite does not increase the amount of pulmonary lipid and phospholipid. On the basis of the strong aldehyde bisulphite-toluidine blue (ABT) positivity of the macrophages containing bentonite, it may be assumed that the bentonite particle surface has an oriented polysaccharide and/or protein coat released from necrotized leukocytes, which protects the macrophage from the strong cytotoxic (necrotizing) effect of bentonite.

Topo-optical reactions of the human blood platelet membrane

The polarization optical analysis of human blood platelets was carried out by means of topo-optical staining reactions. Similar studies have not been performed so far. With this approach we were able to demonstrate the spatially oriented nature of glycoprotein components in the platelet membrane. Using a sialic acid specific topo-optical reaction the sialic acid component of human platelet membrane was selectively demonstrated and the even distribution of sialic acid residues on the membrane surface was also suggested. Polarization optical analysis has shown a membrane-parallel orientation of oligosaccharide chains carrying sialic acids.

Cytochemical demonstration of the molecular forms of cardiac glycosides in the heart muscle

Selective topo-optical staining of vicinal-OH groups with aldehyde-bisulphite-toluidine blue (ABT) has been used for studying the localization and molecular structural order of cardiac glycoside in heart muscle. The glycoside has strong metachromatic basophilia and negative birefringence. In addition to confirming the electron microscopic suitability of the ABT reaction has offered also ultrastructural evidence for the reliability of the topo-optical method. The localization appeared to be in extracellular connection with the outer side of sarcolemma membrane, internal surface of endothelial cell, and in the subsarcolemmal cysterne. The findings suggest that the topo-optical reaction is suitable for molecular analysis of cardiac glycoside.

Topo-optical reactions and polarization optical analysis of human lymphocytes

The latent birefringence of lymphocyte membranes of various species may readily be studied and analysed by various topo-optical reactions. The membranes of glutaraldehyde-fixed and PBS-washed lymphocytes show continuous birefringence with thiazine- and quinoline dyes. According to polarization optical analysis thiazine dye-stained cells are radially positive, whereas quinoline dye-stained cells are radially negative spherites, i.e. thiazine dye molecules are in a perpendicular, quinoline dye molecules in a parallel orientation relative to the membrane surface. These findings suggest that in lymphocyte membranes glycoproteins are primarily responsible for the topo-optical reactions. The actual conformational state of the glycoprotein components is a decisive factor not only in dye binding but also in the orientation of dye molecules. Heparin treatment directs attention to an important interaction between heparin and membrane glycoproteins. With the aid of the critical electrolyte concentration (CEC) technique we were able to demonstrate an ultrastructural differences between human erythrocyte and human lymphocyte membranes. After this procedure the birefringence of erythrocyte membranes was lost, whereas that of lymphocyte membranes did not change. There were no differences between the topo-optical reactions of T and B lymphocytes.

Acid polysaccharide content of frog rod outer segments determined by metachromatic toluidine blue staining

Sulfonation of periodate-oxidized vicinal hydroxyl groups on a polysaccharide backbone allows binding of toluidine blue (aldehyde bisulfite-toluidine blue or ABT staining) with a concurrent metachromatic shift of the dye's absorption peak from 630 nm (monomer) to 580 nm (isolated dimer interaction at vicinal sulfonate groups) or 540 nm (dye polymer interaction). A molar absorptivity of 2.358 +/- 0.134 X 10(4) at 540 nm for polymeric toluidine blue O chloride (TB) aggregates was determined by spectrophotometry of TB bound to hyaluronic acid (HA) and sulfonated glycogen (SG) in water. Microspectrophotometry of ABT stained frog rod outer segments (FROS) showed spectra similar to TB in aqueous HA and SG solutions with absorbances corresponding to 0.063 M dye bound to sugar. Given two dye molecules bound per sugar residue and a rhodopsin concentration of 3.25 mM in FROS, the above indicates 10 stainable sugars per rhodopsin are contained in these cells. Half of these sugars are sensitive to hyaluronidase digestion implying 5 glycosaminoglycan (GAG) repeating units and 5 stainable oligosaccharide sugar residues per rhodopsin in FROS. The GAGs in FROS appear to be primarily HA. Birefringence measurements at 475 nm indicate that this HA and the oligosaccharide of rhodopsin are anisotropically oriented in these cells.

Polarization microscopic investigation of subarachnoid fibrosis after subarachnoid haemorrhage

The author used the polarization microscope and topo-optical reactions such as phenol reaction, collagen-specific sulphation, and picrosirius red F 3 BA staining to investigate the nature of subarachnoid fibrosis after experimental subarachnoid haemorrhage. It is strongly suggested that the subarachnoid fibrotic deposits--which here analysed in a previous study by scanning electronmicroscopy--contain a high amount of collagen as a main component both three weeks and three months after the SAH.

The carbohydrates in frog retinal rod outer segments

Frog retinal rod outer segments appear to contain uncharacterized chemical components whose mass is roughly equivalent to 12--51% of the rhodopsin mass. Available data suggest that such components include soluble proteins and complex polysaccharides, and that hyaluronic acid accounts for a substantial fraction of this mass. Electron microscopic histochemical staining studies suggest that these polysaccharide components are located within the ROS disks. The oligosaccharide moieties of rhodopsin also appear localized within the disks. The interdisk cytoplasm may contain carbohydrates, but their quantity and identity are uncertain. Rhodopsin oligosaccharides as well as some fraction of the intradisk polysaccharide appear to have extended saccharide chains preferentially oriented perpendicular to the surface of the disk membrane. Possible roles for these polysaccharides in disk development and photoexcitation are discussed. The immediate need for complete rod outer segment chemical composition data is emphasized.

Description and interpretation of morphological changes in canine kidneys after preservation with hypothermic solutions and subsequent reperfusion

The morphological appearance of canine kidneys preserved with hypothermic solutions of three different types (Rheomacrodex, Collins 3 and Sacks-II) was studied in acute autologous reperfusion models. While at the end of preservation the renal structure still seemed intact (with the exception of the Rheomacrodex model), reperfusion was associated with the manifestation of hitherto latent structural lesions. This is confirmed by light-microscopic features (hydropic swelling and destruction of the tubular epithelium), enzyme histochemical studies (positive alkaline phosphatase reaction of the Bowman space) and topo-optical reactions (loss of anisotropy of the cytomembranes in the presence of fairly well preserved birefringence of the basement membranes).

Study of factors affecting the antigen structure of the donor kidney. I. Interpretation of the relationship between periodate pretreatment and the rejection phenomena of canine kidney allografts

Donor kidneys were preserved in a Collins-4 solution containing periodate in concentrations of 10(-2) and 10(-4) mole/l, respectively, in an attempt to oxidize the carbohydrate components of the antigen-carrying membrane surfaces and thus to influence the rejection phenomena exhibited by the allogeneic kidney. All kidneys were, however, rejected as a result of a hyperacute reaction indicating that periodate did not react with the hydrophobic membrane structures in vivo. Not only did the antigen thus remain unchanged but the vulnerability of other renal structures to the destructive effect of the killer cells also increased as a result of toxic damage.

Anisotropic staining of apurinic acid with toluidine blue

Using normal rat liver imprints, studies were carried out on the effects of histone extraction and the formation of aldehyde groups from deoxyribose on anisotropic toluidine blue staining of depurinized DNA after sodium bisulfite treatment. The anisotropic effect of bisulfite was found to be determined by binding of bisulfite ions to the aldehyde groups of apurinic acid which, together with free phosphate groups of DNA ensure coparallel attachment of the dye molecules. It was also shown that at pH 5.0 toluidine blue binds with both the phosphate and aldehyde groups of apurinic acid, to give anisotropic staining.

Studies on the molecular arrangement of RNA in tissues with a selective topo-optical reaction of RNA

Selective demonstration of RNA in tissues was achieved by treating tissue sections with potassium permanganate followed by bisulfite and toluidine blue at pH 1.0 (PBT reaction). It is suggested that this reaction is due to aldehyde groups which are formed by the oxidative cleavage of the pyrimidine rings of RNA which can be selectively demonstrated using bisulfite-toluidine blue as the aldehyde reagent. The specificity of the reaction was tested after RNAase treatment, after acid hydrolysis, and on pure RNA droplets. The aldehyde nature of the reacting groups was checked, after permanganate oxidation, by Schiff's leucofuchsin reagent, and by aldehyde blocking reactions. Two types of intracellular molecular arrangement of RNA molecules could be distinguished by polarization optics after application of the PBT reaction: 1) The strong birefringence, dichroism and metachromatic staining of membrane-bound RNA in ergastoplasm of pancreas, liver and plasma cells indicate a linear (planar) molecular order of RNA molecules on the surface of the membranes, and 2) the isotropic, basophilic staining of RNA not organized in membrane structures (Nissl substance, nucleoli) suggest a random distribution of their dye binding sites.

A critical re-evaluation of the anisotropic index used in polarization microscopy: a study on epiphyseal cartilage

Topo-optical reactions specific for collagen and glycosaminoglycans were performed on epiphyseal cartilage plates which differed in age, in chemical composition, and in structure. Retardation values were measured with the polarization microscope and anisotropic index values were calculated after each reaction. It was found that the anisotropic index proposed earlier for quantitative evaluation of topo-optical reactions did not refer either to the submicroscopic orientation pattern or to the quantity of cartilage matrix components. It is suggested that retardation values of induced birefringence may be only used to characterize the spatial orientation of these components in the cartilage matrix.

Ultrastructure of elastic fibers as shown by polarization optics after the topo-optical permanganate-bisulfite-toluidine blue (PBT) reaction

Permanganate-bisulfite-toluidine blue (PBT) reaction proved to be a highly selective and sensitive method for demonstration of elastic structures in tissue sections. Permanganate oxidation liberates a great amount of aldehyde groups in young and adult elastic fibers both in bovine ligamentum nuchae which can be demonstrated with the bisulfite-toluidine blue (pH = 1.0) staining procedure. There are suggestive evidences that the aldehyde groups are liberated from the desmosine and isodesmosine cross bondings of elastin. The dichroism and the strong birefringence of the elastic fibers induced by the PBT reaction indicate a high degree of linear fibrillar molecular order of the reacting elastin molecules which are assumed to be arranged helically in the aortic elastic fibers and they are assumed to show 2 different micellar textures in ligamentum nuchae fibers as reported with other topo-optical reactions earlier by Romhanyi.

[Investigation of the anisotropy of glycocalyx stained with 1.9-dimethyl methylene blue and N,N'-diethylpseudoisocyanine chloride (author's transl)]

In the present study the anisotropic staining of the erythrocyte membrane with 1.9-dimethyl methylene blue and N,N'-diethylpseudoisocyanine chloride was studied and simultaneously compared with the toluidine blue topo-optical staining. The difference between anisotropic toluidine blue and 1.9-dimethyl methylene blue staining, except after KMnO4-oxidation, was only of quantitative nature. On the contrary, striking differences were observed between N,N'-diethylpseudoisocyanine chloride staining, and toluidine blue or 1.9-dimethyl methylene blue staining. Enzymatic and chemical degradation resulted the disappearance of N,N'-diethylpseudoisocyanine chloride staining. Following these treatment membrane birefringence could be restored by aldehyde bisulfate and/or KMnO4-oxidation, while the N,N'-diethylpseudoisocyanine chloride staining was restored only after KMnO4-oxidation. After methylation or acetylation the membrane birefringence disappears, while after KMnO4-oxidation both topo-optical reactions return. The digitonin reaction brought about a rearrangement of the glycocyalyx components. The results draw attention to the spatial orientation of the glycoprotein of the erythrocyte membrane. The role of glycocalyx in the three topo-optical reactions was thus clearly demonstrated.

Orientation of acidic polysaccharides and rhodopsin-oligosaccharides in frog retinal rod outer segments

Using topo-optical staining reactions, the presence and molecular order of three structural components of outer segments of frog retina were studied. These components included (1) an acidic polysaccharide texture, (2) free aldehyde groups which arise during formalin fixation and (3) the oligosaccharide chains of rhodopsin. Quantitative measurements of the dye binding and birefringence effects arising from the individual structural components in rod outer segments were made. Results indicated that all three structural components had a rather well-defined orientation within the ROS. The spherulites phagocytized from the apical ends of ROSs by the pigment epithelium also demonstrate preferred orientation of the three structural components investigated.

Histological and histochemical investigations of the epiphyseal cartilage in rats after administration of heparin, coumarin as well as coumarin and diphosphonate (EHDP)

Heparin and coumarin (Marcumar) as well as coumarin combined with a diphosphonate (EHDP) were examined histologically and histochemically with regard to their effect on the structure of the epiphyseal cartilage in rats. Topo-optical reactions were used to assess the submicroscopic structural changes in the developing trabeculae of metaphysis. The zone of resting cartilage and the zone of young proliferation cartilage in epiphyseal plates revealed a reduced cell count due to the influence of anticoagulants. With regard to the matrix of the epiphyseal plate, it may be stated that its ultrastructure appeared partly regular and that, on the other hand, large areas of degeneration were detected in the connective-tissue. The negative effect of anticoagulants on the ground substance could not be reduced definitely by means of a diphosphonate (EHDP) in conjunction with Marcumar which was administered simultaneously.

Description and interpretation of structural changes in canine kidneys after preservation with a hyperosmolar solution and reperfusion

The effects of hypothermic preservation of canine kidneys for 24 hours by the use of the Sacks solution, and additional autogenous reperfusion were studied by means of submicroscopic morphological methods. While preservation with the Sacks solution was to ensure normal organization of the lipoprotein structures of the basement and cell membranes, in case of additional reperfusion, even of short duration, a substantial or complete loss of anisotropy of the cytomembranes was demonstrable. The present report is the first to be published in the literature on polarization microscopic studies concerned with the effects of kidney preservation and of reperfusion.

[Investigations on the glycocalyx with toluidin blue staining (author's transl)]

The study was concerned with the molecular structure of the erythrocyte membrane and its anisotropic staining with toluidine blue. Enzymatic or chemical degradation impairs the topo-optical staining. Decreased anisotropy results also from digitonin treatment of glutaraldehyde fixed cells. Incubation in a mixture of chloroform and methanol abolishes the anisotropic staining with toluidine blue, but it has been restored by the aldehyde bisulfite-procedure. The efficacy of a treatment with chloroform-methanol is greatly reduced int eh case of agglutinated erythrocytes. The reversibly collapsed glycocalyx is devoid of topo-optical staining. The findings refer to the spatial orientaiton of glycoproteins at the cell surface. Degradation or loss and rearrangement, respectively, change the glycocalyx structure and likewise deteriorate the condition for the anisotropic staining. Alterations of the lipid layer of the membrane may result in similar effects. There was, however, no indication of an intercalation into the lipid layer of dyestuff molecules. In conclusion, the topo-optical toluidine blue staining is considered a powerful method aiding studies of the glycocalyx of erythrocytes (and presumably of other types of cells too).

Optical studies on the molecular-sterical mechanism of metachromasia

We have investigated how the stereochemical situation of the dye binding negative side groups on polysaccharides influences metachromatic staining effects. We found that selective binding of toluidine blue (pH = 1.0) in the places of substituted (acidified) vicinal OH groups C2 and C3 resulted in the clearest metachromasia with the strongest anisotropy effects and with a bright clear green polarization color. On the other hand, selective toluidine blue binding in the places of C6 of the carbohydrate rings of the polysaccharide chains resulted in orthochromatic basophilia and lack of birefringence. After transformation of all OH side groups into negatively charged groups, metachromatic staining was found mixed with an orthochromatic hue and a birefringence effect weaker than in the case of staining on the vicinal OH groups only. The need of poststaining stabilization of the labile metachromatic staining reactions is emphasized.