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Photosensitivity in thiopyronine-resistant yeast mutants.

In yeast, thiopyronine (TP) acts both as a growth inhibitor (in the dark) and a photodynamic sensitizer (in the light). We have isolated a large number of TP-resistant mutants of Saccharomyces cerevisiae and characterized them by genetic and photobiological techniques. Resistance to the growth-inhibitory (dark) effects of TP can arise by mutations in at least four separate genes. Growth-inhibitory and photodynamic effects of TP can be genetically separated, as evidenced by the finding that resistance mutants affected in three of the genes were not altered in their photodynamic response to the dye. In contrast, a mutation in the fourth gene simultaneously conferred high resistance to both the growth-inhibitory and photosensitizing effects of TP, suggesting that a mutation had occurred at a step common to the expression of both effects. Preliminary data suggest that this mutation reduces the ability of the cells either to take up, or bind, TP.

Drug Resistance, Microbial↗

The importance of cerebrospinal fluid on neural cell proliferation in developing chick cerebral cortex.

Cerebrospinal fluid (CSF) is mainly produced by the choroid plexuses within the ventricles of the brain. The CSF circulates in a regular manner after the ventricular system and the choroids plexuses have developed, and the foramina in the fourth ventricle have opened to enable it to carry chemical information. CSF flows through the ventricular system passing over all regions of germinal activity. In this study, chick embryos were used to show the importance of CSF on neural cell proliferation in the developing cerebral cortex. The chick embryos were cannulated in situ with a fine capillary tube to drain CSF out of the ventricular system. At the same time, BrdU was administered to the embryos. After surgery the embryos were incubated for another 3 days. Quantitative measurements showed that the thicknesses of the germinal epithelium and cerebral cortex in CSF-drained embryos were less than those in the control group at the same age. The number of cells produced in the germinal epithelium of CSF-drained embryos was decreased when compared with the normal group. This study provides confirmatory evidence that CSF is important for neural cell proliferation and therefore normal development of the cerebral cortex. It is proposed that CSF is vital in controlling development of the cerebral cortex.

Animals↗

Thiopyronine- and 8-methoxypsoralen-sensitized photodynamic effect on cell growth, colony forming ability and RNA synthesis in Saccharomyces mutants deficient in DNA repair.

We compared the photodynamic effects of thiopyronine (TP) and visible light, and 8-methoxypsoralen (8-MOP) and ultraviolet A (UV-A) light, on growth, colony forming ability and RNA synthesis in a repair-proficient Saccharomyces strain and three mutants deficient in DNA repair mechanisms (DNA repair assays). With 8-MOP and UV-A repair-deficient mutants were significantly more sensitive than the repair-proficient strain indicating that the system is sensitive for the detection of DNA damage. With TP and visible light, the photodynamic effects were comparable in the mutants and the control, indicating no DNA damage. These results support previous work showing that the main target of TP photosensitization in eukaryotes is not nuclear DNA.

Cell Division↗

Photodynamic inactivation and mutagenesis by angelicin (isopsoralen) or thiopyronin (methylene red) in wild-type and repair-deficient strains of bacteriophage T4.

Photodynamic inactivation of bacteriophage T4 particles, mediated by either angelicin or thiopyronin, is enhanced by defects in the T4 uvsW-uvsX-uvsY postreplication repair system but not by a defect in the denV pyrimidine-dimer-excision system. There was no evidence for functional interactions between the two repair systems. As observed previously with 8-methoxypsoralen, photodynamic mutagenesis with angelicin is abolished by defects in the uvsW-uvsX-uvsY system.

DNA Repair↗

Salient features of Haemophilus vaginalis.

A total of 78 strains of Haemophilus vaginalis were examined for 104 features. All strains fermented dextrin, maltose, and starch. Additionally, more than 90% of the strains fermented galactose, glucose, and ribose. Arbutin, cellobiose, melibiose, rhamnose, and salicin were not fermented by any of these strains. None of the strains acidified any of 14 alcohols or alkalinized any of 25 organic salts and amides. More than 90% of the strains hemolyzed human blood agar and hydrolyzed hippurate. No strain hemolyzed sheep blood agar. A recommendation is included for those minimal features that best differentiate H. vaginalis from other oxidase- and catalase-negative, gram-negative organisms.

Bacitracin↗

Evaluation of a new technique for the demonstration of gonococci and other micro-organisms in host cells.

A method (Gram-MGPLG) for demonstrating micro-organisms was compared with Gram and four other known methods. Each method was tested on tissue infected with Staphylococcus aureus, Pseudomonas aeruginosa or Neisseria gonorrhoeae, which were then fixed in Bouin's formol saline, formol sublimate, or Van de Grift solutions. Gram-positive organisms in tissues were easily seen even at low magnification when stained by several of the methods tested. Gram-negative organisms, however, are very difficult to locate when stained by Gram's method because tissue components and the organisms are all shades of red, whereas the Gram-MGPLG provided easier location of organisms because these are stained red while the nuclei are blue and connective tissue is green. All methods are markedly affected by fixation; better preservation of cytological detail and improved staining reactions were produced by fixative containing mercuric chloride.

Evaluation Studies as Topic↗

Rhinitis of pigs: A gross staining method for macroscopic examination of the nasal mucosa.

A phloxine-alcian blue (PhAB) method has been used to stain the porcine nasal mucosa for macroscopic examination. Applied to either fresh or fixed specimens it stains respiratory epithelium dark blue and non-cilated epithelium, including the metaplastic epithelia of rhinitis, bright pink. The PhAB technique is simple, inexpensive and dependable, and is suitable for routine application in the post mortem room. Stained and fixed specimens may be preserved virtually indefinitely.

Alcian Blue↗

Response of synovial immunocytes to intra-articular agents in experimental arthritis.

In rabbits with immune arthritis the numbers of lymphoid aggregates and pyroninophilic and non-pyroninophilic cells per unit area of synovium were calculated from sections taken at various intervals after intra-articular drug injections. A model of immune arthritis based on the results is presented. In the active phase of the arthritis, plasma cells, plasmablasts and lymphoid aggregates proliferate, while the number of lymphocytes decreases. In the inactive phase after treatment, the cell pattern is the reverse. The ratio of pyroninophilic to non-pyroninophilic cells proved to be a good measure of the activity of the arthritis. A favourable therapeutic effect was achieved with triamcinolone hexacetonide and combined steroid-osmic acid, but not with osmic acid alone.

Animals↗

Alterations of selected intestinal enzymes in hamsters with hamster enteritis syndrome.

Portions of duodenum, jejunum, and ileum from 21 hamsters clinically affected with enteritis were examined for enzymes. Utilizing a variety of techniques, the activities of alkaline phosphatase, nonspecific esterases, leucine aminopeptidase, beta-glucuronidase, and methyl green pyroninophilia were determined. The activities of enzymes normally associated with tissue proliferation and active protein synthesis were decreased, whereas those enzymes associated by cytolysis were increased.

Alkaline Phosphatase↗

[A cell-line with 27 chromosomes in a human acute leukemia (author's transl)].

Chromosomal analysis of the bone-marrow aspirate of a five years old girl suffering acute leukemia revealed a cell-line carrying 27 chromosomes. Banding by controlled heating denaturation showed that, in these cells, all chromosomes are haploid, except chromosomes: X, 10, 18, 21. This cell-line, not seen during remission, was found during relapse, in addition to another one with 54 chromosomes. The caryotype of this last clone corresponded to the duplication of the chromosome set found in the first cell-line. The authors discuss two problems: the possible correlations between the clinical evolution and the biological data; the problem raised by the survival and proliferation of such an hypodiploid cell-line.

Acid Phosphatase↗

[The use of melamine-formaldehyde latex in the automated analysis of immunocompetent cells].

The optimization of the loading of monodispersed melamine-formaldehyde latex with fluorochrome has permitted its use as indicator material, equally suitable both for the visual evaluation of the reaction of phagocytosis and for the automated evaluation of this reaction by means of a scanning fluorescent microscope. The study has shown the possibility of using fluorescent melamine formaldehyde latex for the evaluation of the phagocytosis of mouse peritoneal macrophages and human blood cells, as well as the analysis of the surface receptors of immunocompetent cells.

Animals↗

Decay of methyl green-pyroninophilia in Burkitt's lymphoma.

The spontaneous decay of methyl green-pyroninophilia in Burkitt's lymphoma was studied at four temperatures (0 degrees C to 56 degrees C) in four biopsies using Kurnick's method. The decay is temperature and time related and is presumably due to intrinsic enzymatic action, probably ribonuclease. Imprints from tumor tissue preserved at 0 degrees C lose pyroninophilia by six hours; from tumor preserved at room temperature pyroninophilia, in most instances, would have been lost by three hours, from tumor tissue maintained at 37 degrees C, by two hours in most instances and by 15 minutes at 56 degrees C in most instances. The absence of pyroninophilia after these intervals at the appropriate temperatures should not detract from the diagnosis of Burkitt's Lymphoma.

Burkitt Lymphoma↗