Biomedical subjects

S E Bloom

Publications and source records attributed to S E Bloom.

7 recordsLinked to original sources

PubMed1979

Further study of the genetic toxicity of gentian violet.

The genetic toxicity of gentian violet was studied with the Ames and the Rosenkranz bacterial assays as well as the cytogenetic assays (Chinese hamster ovary cells in vitro in the presence of rat-liver S-9 fractions, the chicken-embryo and mouse-bone-marrow cells in vivo). Gentian violet was found to be toxic but not mutagenic in the Ames assay. However, it was active in the Rosenkranz assay causing reparable DNA damage. The presence of S-9 in the in vitro cytogenetic assay and in the bacterial assays showed that the activity of gentian violet could be reduced or eliminated. In the in vivo assays, gentian violet was not clastogenic and failed to induce sister-chromatid exchanges. However, gentian violet proved to be highly toxic to growing chick embryos at high dosage and depressed mitotic activities in mouse bone marrow after prolonged treatment. Our study suggested that gentian violet can be inactivated by the liver detoxification system. However, it is potentially hazardous to cells that are exposed to the dye directly (e.g. skin epithelium and cell lining of the gastrointestinal tract).

Animals↗

PubMed1977

Distribution of F-bodies, heterochromatin, and nucleolar organizers in the genome of the central mudminnow, Umbra limi.

Due to the very limited amount of knowledge available on the cytochemistry and architecture of fish chromosomes, an extensive banding study was carried out on chromosomes of the central mudminnow, Umbra limi. Through the use of fluorescent staining, C-banding, and silver staining, the chromosomes were characterized, and an idiogram was constructed showing the location of C-band heterochromatin, F-bodies, and the nucleolar-organizer regions. G-banding was attempted but was unsuccessful. Results of fluorescent staining with 33258 Hoechst and quinacrine HC1 raised some interesting questions concerning the cytochemistry of U. limi chromosomes, as well as the specificity of these stains.

Animals↗

PubMed1976

An improved technique for selective silver staining of nucleolar organizer regions in human chromosomes.

A reliable technique for staining human chromosomal nucleolar organizers (NOR's) with silver solutions is described. The NOR's can be selectively stained dark brown by silver solutions leaving the chromosome arms unstained and available for counterstaining with orcein or Giemsa dyes. Unequivocal identification of chromosome pairs bearing NOR's can be achieved using fluorescent banding techniques followed by silver staining. The silver staining procedure for NOR's was simplified and standardized through control of the chemical and physical conditions during silver impregnation and developing.

Chromosomes↗

PubMed1976

Sister chromatid differentiation and exchanges in adult mudminnows (Umbra limi) after in vivo exposure to 5-bromodeoxyuridine.

An in vivo system for the detection of sister chromatid exchange (SCE) in the central mudminnow, Umbra limi, is presented. Sister chromatid differential (SCD) and SCE were demonstrated by fluorescent and Giemsa procedures 5 to 6 days after the fish were injected with 500 mug/g of BrdU. The exchange rate was found to be 2.64 SCEs metaphase in the intestines and 2.42 SCEs/metaphase in the gills. SCE analysis in U. limi should be a useful tool for measuring the mutagenicity of water-borne chemicals.

Animals↗

PubMed1976

Human nucleolus organizers: the satellites or the stalks?

A silver-staining technique specific for demonstrating nucleolus organizer regions (NOR) showed that the achromatic stalks of the 10 acrocentric autosomes of the human complement represent the NORs. Some variability in number of stained stalks is observed from cell-to-cell and from individual-to-individual. The silver-stained masses may extend beyond the stalks and cover the satellites, especially in chromosomes with short stalks or minute satellites.

Cell Nucleolus↗

PubMed1975

Visualization of nucleolar organizer regions im mammalian chromosomes using silver staining.

A simple ammoniacal silver staining procedure, designated Ag-AS, differentially stains the chromosomal locations of ribosomal DNA in certain mammalian species. This was critically demonstrated by Ag-AS staining of the nucleolus organizer regions in karyotypes of the same species and cell lines used for locating the ribosomal cistrons by DNA/RNA in situ hybridization. With Ag-AS, silver stained NORs (Ag-NORs) are visualized as black spherical bodies on yellow-brown chromosome arms. Ag-NORs were visualized throughout mitosis at the secondary constrictions in the rat kangaroo, Seba's fruit bat, Indian muntjac, and Rhesus monkey. The Chinese hamster and cattle have telomeric Ag-NORs, the mouse subcentromeric Ag-NORs, and the field vole Ag-NORs as minute short arms or choromosomal satellites. Ag-NORs occur at both secondary constrictions and at telomeres in the cotton rat. Variability in Ag-NOR pattern included differences in the number of Ag-NORs per cell within a cell population, size of Ag-NORs among chromosomes of a complement, and presence of Ag-NOR on particular chromosomes in two cell lines of the Chinese hamster. The available cytochemical data suggest that the Ag-AS reaction stains chromosomal proteins at the NOR rather than the rDNA itself.

Animals↗

PubMedDate not supplied

Influence of the bn gene on mitosis of immature red blood cells in turkeys.

The binucleated and large mononucleated red blood cells found in the blood of bnbn mutant turkeys result from nondisjunction of chromosomes in bone marrow polychromatic erythrocytes. The major ultrastructural abnormality that is observed in these mutant cells is malpositioning of the centrioles in the cell. This involves failure to assume a normal pole-to-pole position in the center of the cell, and, often, centrioles are seen close together near the cell membrane. In addition to the abnormalities in centrioles, incomplete spindles are formed with large masses of chromatin unattached to microtubules. Cytokinesis is blocked in many instances because large amounts of chromatin remain at the region of the metaphase plate. None of the aforementioned abnormalities were seen in bone marrow cells from genetically normal turkeys. The results of this study suggest that malorientation of the centrioles has adverse effects on chromosome movement in animal cells. The concept that the spatial orientation of the centrioles is fundamental in achieving normal separation of chromosomes during anaphase movement is supported by our work. Finally, the close ultrastructural parallels with the human blood disease congenital dyserythropoietic anemia type I are discussed.

Animals↗