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Biomedical subjects

J C Stockert

Publications and source records attributed to J C Stockert.

At least 73 records · Page 4Linked to original sources
PubMed1989

An intercalative and minor groove binding model for the DNA cleavage reagent, copper(I) (1,10-phenanthroline)2.

On account of the stereochemical structure and interaction characteristics of the DNA cleavage reagent copper(I) (1,10-phenanthroline)2, both intercalative and minor groove binding modes to B-DNA could be expected to occur. In the proposed model, the suitable dihedral angle between phenanthrolines allows that one of the two planar ligands partially intercalates between base pairs, and meanwhile the other ligand locates along the minor groove.

Animals↗
PubMed1989

Linear dichroism and polarized fluorescence of dye-complexed DNA fibers.

A simple method to obtain well orientated DNA fibers for studying the ordered binding of dyes and fluorochromes by linear dichroism and polarized fluorescence is described. The metachromatic dye toluidine blue and the intercalating fluorochromes ethidium bromide and acridine orange showed a perpendicular alignement to DNA; the minor groove binding fluorochromes 33258 Hoechst and DAPI appeared parallel. Thus, DNA fibers represent a suitable cytochemical test substrate for studying the orientation of bound dyes by polarization methods.

DNA↗
PubMed1989

Chronic intoxication by heroin; histopathological effects on seminiferous tubules.

Seminiferous tubules from heroin abusers and from rats chronically intoxicated by heroin samples presented a striking reduction in the thickness of the germinal epithelium. Light and electron microscopical studies showed a considerable increase of lipids and phagosomes in Sertoli cells, disorganization of their junction complexes, detachment of immature germ cells which appeared free in the tubular lumen, and formation of giant multinucleate spermatids. These alterations point out that Sertoli cells could be the target element for the toxic effect of heroin samples on the seminiferous epithelium.

Adult↗
PubMed1989

Monomerizing effect of caffeine, o-phenanthroline, and tannin on cationic dyes: a model system to analyze spectral characteristics of the intercalative binding to nucleic acids.

If used as co-solutes in concentrated solutions of cationic planar dyes, caffeine, o-phenanthroline, and tannin induce striking hyperchromic and bathochromic shifts in their absorption spectra. Likewise, the fluorescence of acridine orange at high concentration greatly increases in the presence of caffeine, the emission peak appearing at a shorter wave-length. These spectral changes, which are similar to those produced by organic solvents, detergents, and alpha-cyclodextrin, reflect the disaggregating (monomerizing) capacity of the co-solutes on stacked chromophores. After washing with saturated solutions of caffeine or o-phenanthroline, the chromatin fluorescence by intercalating fluorochromes is reduced or abolished, which suggests competition effects for intercalative binding modes. These results support the use of caffeine, o-phenanthroline, and tannin in spectroscopic and histochemical studies of dye-stuff interactions with DNA and chromatin.

Caffeine↗
PubMed1989

Tungsten and molybdenum heteropolyacids as staining and contrasting agents: reactivity with epoxyresin-embedded cell and tissue structures.

In this work, we carry out a further approach to the knowledge of the reaction mechanism of phosphotungstic and phosphomolybdic acids (PTA and PMA), as well as some derivatives, with cell structures from epoxyresin-embedded materials. Applied on thin sections from glutaraldehyde-fixed tissues, PTA and PMA induced a strong electron contrasting reaction in spermatid acrosomes, goblet cell mucin, callose and plant cell walls, endexine, intine and starch granules. In light microscopy, the localization of heteropolyacids on these structures was achieved by treatments of semithin sections with suitable reducing agents (titanous sulfate, stannous chloride, sodium borohydride, or p-phenylenediamine) to form the mixed-valence heteropolyblues, or with Schiffs's reagent. The use of PTA-dye complexes (pyronin-PTA and Mallory's PTA-hematoxylin) also showed the same staining pattern. Taking into account the chemical characteristics of the PTA- and PMA-reactive tissue elements, the present results indicate that heteropolyacids selectively enter into the highest hydrophilic structures from non-polar epoxy-embedded sections; after brief washing, they appear predominantly retained in tissue structures containing a great amount of carbohydrate components.

Animals↗
PubMed1989

Alcian yellow as a fluorescent dye.

Fluorescence characteristics of the cationic dye Alcian yellow are described. Under ultraviolet excitation, the chromatin and basophilic cytoplasm from cell smears show a blue-white emission, which depends on the presence of nucleic acids. Glycosaminoglycans-containing structures (mast cell granules, cartilage matrix) appear brightly fluorescent. The excitation at 320 less than or equal to lambda less than or equal to 340 nm is the most suitable, and the emission wavelength shows dependence on the dye concentration.

Animals↗
PubMed1989

Aluminium binding to chromatin DNA as revealed by formation of fluorescent complexes with 8-hydroxyquinoline and other ligands.

After aluminium mordanting of chicken blood smears, several chelating dyes and reagents were tested in order to detect the metal binding to chromatin DNA by fluorescence microscopy. 8-Hydroxyquinoline induced the most selective fluorescence reaction, which was abolished after DNase or trichloroacetic acid treatment. Morin, purpurin and nuclear fast red showed an intense nuclear fluorescence, but lower selectivity. Fluorescence was also observed in chromatin treated with morin or curcumin without mordanting. The simplicity and microscopical characteristics of the A1/8-hydroxyquinoline fluorescence reaction make it very suitable for cytological studies of chromatin.

Aluminum↗
PubMed1989

Influence of fixation, exciting light and section thickness on the primary fluorescence of samples for microfluorometric analysis.

The primary fluorescence (autofluorescence) of some cell and tissue components depends on the fixative and fixing time, as well as on the thickness of paraffin sections and the wavelength of exciting light. The highest autofluorescence emission (pale green) was observed by using violet-blue excitation. After aldehyde fixation, the autofluorescence of some tissue structures was higher than after methanol or ethanolacetic acid. These features must be taken into account when fluorescence microscopy is applied to the study of cell smears and paraffin embedded tissues after flurochroming or immunofluorescence reactions.

Animals↗
PubMed1987

Metachromatic staining and electron dense reaction of glycosaminoglycans by means of cuprolinic blue.

The cationic phthalocyanin-like dye Cuprolinic Blue, unlike phthalocyanin dyes such as Alcian Blue or Astra Blue, can definitely exhibit a clear metachromatic reaction with appropriate substrates. The application of Cuprolinic Blue to epoxy-embedded semithin sections revealed that mast cell cytoplasmic granules, goblet cell mucin and cartilage matrix stained in violet shades (metachromatic), whereas nuclear chromatin presented a bright blue coloration (orthochromatic). The metachromatic structures showed a high degree of contrast when ultrathin sections treated with Cuprolinic Blue were examined by electron microscopy. Cytophotometric measurements of stained components from the large intestine showed different absorption maxima: at 580 nm for mucin and at 640 nm for nuclei. The spectroscopical analysis revealed a clear-cut metachromatic shift when the dye was in the presence of chondroitin-4-sulphate. The addition of aluminium metal to Cuprolinic Blue solutions resulted in a striking spectral change; under such conditions the dye showed absorption maximum at 530 nm.

Animals↗
PubMed1987

Differential staining of biological structures by ruthenium red.

After the application of a ruthenium red (RR) solution to smears of chicken and human blood for 15 min, thrombocyte and leucocyte nuclei showed a blue-grey colour, contrasting with the red-stained erythrocyte nuclei. Extracellular matrix in frozen sections of cartilage showed the blue-grey colour after 1 h of staining. After the application of RR for a prolonged time (24 h), goblet cell mucin, granules of salivary glands and starch granules in Epon-embedded tissues were coloured blue-grey, blue-green and brown-green respectively; although they appeared red after shorter staining times. Microspectrophotometric measurements of differentially stained structures, and correlation with the spectral behaviour of a related ruthenium compound (ruthenium violet), are presented. The formation in situ of this latter compound by interaction of RR with certain substrates and the capacity of RR to distinguish different cellular structures are discussed.

Animals↗
PubMed1987

Cytochemical study of the fluorescence reaction of chromatin by the porphyrin derivative meso-tetra (4-N-methylpyridyl) porphine.

Application of meso-tetra (4-N-methylpyridyl) porphine (TMPP) on smears of chicken blood revealed an intense red fluorescence on the nuclei under blue-violet exciting light, which seemed to be dependent on the DNA component of chromatin. The possibility that an intercalative binding mechanism based on hydrophobic interaction occurs between TMPP molecules and paired bases of DNA is briefly discussed.

Animals↗
PubMed1986

Autofluorescence and induced fluorescence in Epon embedded tissue sections.

The autofluorescence of tissue components in Epon semithin sections depends on the exciting wavelength, section thickness, and the structure under observation. The degree of autofluorescence emission of a given component affects the fluorescence reaction induced by fluorochromes, a feature which must be taken into account when fluorescence microscopy is applied to the study of Epon sections.

Animals↗
PubMed1986

Increased acidophilia of eosinophil granules after EDTA treatment.

The acidophilic reaction of eosinophil leucocyte granules from human, pig and horse blood smears was investigated by using May-Grünwald-Giemsa staining after previous treatment with EDTA and sodium citrate solutions. The same peak at 530 nm, but absorption values considerably higher than those of controls, were found in eosinophil granules after application of chelating agents, indicating that removal of metal cations could unmask basic groups in these structures.

Animals↗