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Biomedical subjects

J C Stockert

Publications and source records attributed to J C Stockert.

At least 109 records · Page 6Linked to original sources
PubMed1983

Cytochemical mechanisms of chromatin fluorescence and staining reactions by thionin solutions.

After staining with thionin at low concentration (less than 10(-5) M), the masses of condensed chromatin in chicken erythrocyte nuclei show a red fluorescence under green excitation, which is abolished when they become stained by using concentrations higher than 10(-4) M. The possibility that intercalative binding of a hydrophobic component from the dye solution into DNA accounts for this fluorescence reaction in chromatin is briefly discussed.

Animals↗
PubMed1983

Mercurochrome: a fluorescent and electron opaque dye.

Mercurochrome was applied to tissues and tissue sections in an attempt to examine structural components either in visible light, fluorescence or electron microscopy. Samples of bone marrow from rats were fixed in glutaraldehyde alone, embedded in Durcupan, and studied by using semi-thin and thin sections. After treatment with mercurochrome in acetone before embedding, the eosinophilic granules from leucocytes and chromatin masses showed electron opacity as well as a yellowish green fluorescence under excitation with violet-blue or blue light. An additional treatment of sections with an alkaline hydroalcoholic solution of the dye allowed to visualize these structures under bright-field illumination and to improve the contrast in the electron microscope. This method offers the possibility to examine specific cell components by using a compound which simultaneously possesses staining, fluorescence, and electron microscopic contrasting properties.

Animals↗
PubMed1982

Monastral fast blue. Cytochemical properties of a reaction product from Alcian blue stained chromatin.

The staining of chicken erythrocyte nuclei with Alcian blue followed by a treatment with ethanol-NaOH, showed to be highly resistant to acid extraction (5 N HCl) due to the alkaline conversion of Alcian blue into the insoluble pigment Monastral fast blue. It is assumed that the intercalative binding of the planar Monastral fast blue molecule to DNA accounts for its competition effect toward the intercalating fluorochromes acridine organe, ethidium bromine and daunomycin.

Alcian Blue↗
PubMed1982

[Cytochemical methodology applied to the study of staining mechanisms and fluorescence of nucleic acids].

The intercalation of the corresponding product in the DNA molecule is related to activity of some anti-neoplastic antibiotics, and to chemical carcinogenesis and mutagenesis. DNA-intercalating agents may inhibit replication and/or transcription, and stop cell proliferation. This work deals with the mechanisms of staining and fluorescence, and with the intercalative binding of some cationic dyes. It is shown that chromatin fluorescence depends on the product concentration, it is not modified by nitrites, molibdate or inorganic cations, but it is inhibited by non-fluorescent intercalating substances such as caffeine and o-phenanthroline. The results suggest the existence of intercalative binding. Contrarily, chromatin staining is related to electrostatic binding with DNA.

Antineoplastic Agents↗
PubMed1982

Chromatin staining reactions by oxidized p-phenylenediamine and Alcian blue.

After treatment with oxidized p-phenylenediamine or Alcian blue at high temperature, nuclei from chicken and human blood smears showed an intense staining reaction which proved to be dependent on the DNA content of chromatin. The possibility that oxidized p-phenylenediamine binds to phosphate groups and that Alcian blue interacts with bases of denatured DNA is briefly discussed.

Alcian Blue↗
PubMed1982

[Antineoplastic drugs used as fluorochromes].

Several synthetic imide derivatives of naphthalic acid that bind to DNA and have anti-neoplastic properties are studied here in relation to the fluorescence they produce in the chromatin of chicken nucleated red blood cells.

Adenine↗
PubMed1981

Observations on the chromatin staining and fluorescence by safranine O.

After treatment with safranine O at low concentrations (10(-6), 10(-5) M), the chromatin of chicken erythrocytes shows an intense red fluorescence, which is reduced or practically abolished when nuclei become stained by using the dye at concentrations higher than 10(-4) M. Both the fluorescence and staining reactions are dependent on the DNA content of chromatin. Safranine fluorescence of nuclei is not reduced in presence of high salt concentration, while the previous treatment with thiazine dyes diminishes the fluorescence intensity. The possibility that chromatin fluorescence depends on the intercalative binding of safranine is suggested.

Animals↗
PubMed1980

Photographic equidensitometry of metaphase chromosomes.

Photographic equidensitometry, which is a procedure to obtain specific lines or symbols for points of equal optical density, has been utilized in the study of chromosome images. Equidensitometric techniques, using a special contour film, permitted three approaches, namely, production of line equidensities (in the form of families, sequences and contour maps), color equidensifies (color conversion of line sequences), and screen equidensities (substituting characteristic symbols for densities). All these techniques have proved very useful to analyze images of metaphase chromosomes and occurrence of spontaneous banding patterns, by showing the precise distribution and relative values of the grey gradient. This report demonstrates the potential of photograhic equidensitometrical procedures for chromosome studies, which obviates the need to purchase elaborate equipment.

Animals↗
PubMed1980

Cytofluorometric and cytophotometric measurements by using the exposure control device in the automatic photomicroscope.

A simple method for quantitative measurements of staining and fluorescence intensities in microscopic preparation is described. The procedure is based on the use of the automatic exposure capability of the Zeiss Photomicroscope, in which the measuring value on the scale of the exposure control device after an arbitrary time permits the assessment of the light intensity on the point photosensor. The method has been checked through the study of chromatin staining and fluorescence by dyes and fluorochromes which are utilized in nucleic acids cytochemistry. The correpondence between these measurements and those obtained by using other methods is briefly discussed.

Animals↗
PubMed1979

Chromatin fluorescence by pyronin staining.

Human, chicken and mouse cells from different tissues show a bright red-orange fluorescence of the chromatin after staining with pyronin Y. The possibility that intercalation of the dye into double helical nucleic acids accounts for this fluorescence pattern is briefly discussed.

Animals↗
PubMed1979

The formation of ribonucleoprotein droplets in Chironomus salivary gland nuclei.

The appearance of RNP droplets associated with specific regions of polytene chromosomes from Chironomus larvae has been studied, systematically by light microscopy using glutarladehyde fixation and lactic acid squashing of the salivary gland. During the fourth larval instar the highest frequency of nuclei which contained droplets (over 50%) was observed in late prepupae. Several treatments (heat and cold shock, cycloheximide) were found to stimulate the formation of a large number of droplets whose features under the light and electron microscopes seemed to be identical to those observed in untreated larvae. Droplets could be observed either in a free state in the nuclear sap or grouped around specific regions of the chromosome such as some Balbiani rings and puffs. Kinetic studies suggest that droplets first appear in a free state and later group themselves on specific chromosome regions. Transcriptional activity seems to be essential for the process of droplet accumulation in the chromosome, since it does not take place if RNA synthesis is inhibited. Cytochemical tests showed striking similarities between the staining reactions of droplets and those of the fibrillar component of the nucleolus. These observations indicate that droplets probably originate from, or share a common component with, nucleolar material and that this component has a preferential affinity for some active chromosomal loci, where it accumulates.

Animals↗
PubMed1979

Observations on the chromatin staining by aluminium-hematoxylin.

The staining reaction of chromatin by aluminium-hematoxylin was investigated. Intense staining, which proved dependent on nucleic acid content, was achieved by using either the preformed lake, mordanting followed by hematoxylin, hematoxylin alone or the lake at high ionic strength. Extraction procedures removed aluminium ions from chromatin but the lake was retained. Chromatin fluorescence induced by ethidium bromide and acridine orange was abolished after staining with the lake. Intercalating-like forces are suggested for aluminium-hematoxylin binding to chromatin.

Aluminum↗