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Biomedical subjects

Y Daskal

Publications and source records attributed to Y Daskal.

At least 37 records · Page 2Linked to original sources
PubMed1978

Scanning-electron microscopy of chromosome aberrations.

This study is the first report of scanning-electron microscopy of isolated and purified metaphase chromosomes containing drug-induced aberrations. The technique reported allows high resolution topological examination of chromosomal aberrations which may pass undetected with conventional techniques.

Cell Line↗
PubMed1978

Comparative ultrastructural studies of nucleoli of tumor cells treated with adriamycin and the newer anthracyclines, carminomycin and marcellomycin.

This study was designed to determine the effects of several antitimor anthracyclines, including Adriamycin and its analogs, carminomycin and marcellomycin, on the ultrastructure of nucleoli of Novikoff hepatoma cells. Adriamycin and carminomycin, which are structurally related, induce nucleolar segregation following the formation of conspicuous fibrillar centers. Marcellomycin did not induce formation of nucleolar fibrillar centers. Instead, numerous microspherules formed following treatment with marcellomycin; later complete nucleolar segregation developed. The microspherules were observed to be in various stages of extrusion from the nucleolar body. This microspherule "migration" appeared to be both time and drug concentration dependent. These results show that the rate and extent of nucleolar ultrastructural aberration may be related to structural differences of the various anthracyclines.

Animals↗
PubMed1978

Comparison of adriamycin-induced nucleolar segregation in skeletal muscle, cardiac muscle, and liver cells.

Male Sprague-Dawley rats were treated with either 2.5, 3.5, or 5.0 mg/kg of adriamycin by iv injection. After 1 or 3 hours of treatment, samples of liver, cardiac muscle, and skeletal muscle cells were examined by electron microscopy. The changes in ultrastructure observed in these tissues after the first hour included nucleolar segregation and altered distribution of the perinucleolar chromatin. However, no alterations in the ultrastructure of either the nucleus or cytoplasm were observed in tissues examined 3 hours after a 5-mg/kg dose of adriamycin. The doses at which nucleolar alterations occurred varied between tissues. In skeletal and cardiac muscle cells, marked alterations in nucleolar ultrastructure were observed at doses of 3.5 and 5.0 mg/kg of adriamycin. Liver cell nucleoli, however, exhibited few structural aberrations at these doses. The similarities in response of skeletal and cardiac muscle suggest that ultrastructural analysis of skeletal muscle biopsies may be useful in evaluating adriamycin cardiotoxicity.

Animals↗
PubMed1977

Nuclear and nucleolar ultrastructure of Sézary cells.

Sézary cells were studied in the peripheral blood and characteristic skin lesions of the Sézary syndrome and mycosis fungoides by transmission electron microscopy to obtain more information on their nuclear and nucleolar ultrastructure. Sézary cells contain nucleoli with nucleolonemas or ring-shaped nucleoli similar to those of lymphoblasts and mature lymphocytes. "Maturation asynchrony" of the nucleolus and cytoplasm was evident in some cells that contain large numbers of ribosomes and ring-shaped nucleoli and in other cells that contain nucleoi with nucleolonemas and few ribosomes. The maturation asynchrony of the nucleolus and the cytoplasm, the presence of mitochondrion-like inclusion bodies in the nucleus, and fusion of mitochondria with the nucleus in Sézary cells are ultrastructural abnormalities of this neoplastic lymphocytic variant. The presence of the intranuclear "mitochondrion-like" inclusion body and nuclear rodlets in Sézary cells were exceptional findings.

Cell Differentiation↗
PubMed1977

Isolated metaphase chromosomes: scanning electron microscopic appearance of salt-extracted chromosomes.

Scanning electron microscopy of salt extracted, isolated metaphase chromosomes has been used to further the understanding of the role of proteins and DNA in chromosome architecture. Metaphase chromosome surfaces consist of numerous compact microconvules with an average diameter of 520 +/- 78 A which result from several orders of supercoiling. Treatment of isolated chromosomes with various salt concentrations ranging from 0.4 to 2.0 M NaCl revealed a longitudinal array of fibres within the chromatids as well as regions of coalesced nucleoprotein. The results demonstrate sensitivity of chromosome structure based on chromatin supercoiling, to progressive extraction of chromosomal proteins and DNA over the range of salt concentrations examined.

Cell Fractionation↗
PubMed1976

Ultrastructural study of pulmonary bleomycin toxicity.

Ultrastructural manifestations of bleomycin A2 toxicity in the human lung were studied in three patients. In addition to the appearance of nucleolar fibrillar centers, an increase in membranous, beaded, and granular nuclear bodies was found in nuclei of type 1, type 2 alveolar epithelial cells, and interstitial fibroblasts in all treated patients. Few such nuclear bodies were found in specimens of untreated patients.

Adult↗
PubMed1975

Ultrastructural study of the effect of bleomycin A2 on the nucleolus and its possibly related cytoplasmic constituents in Novikoff hepatoma cells.

Treatment of Novikoff hepatoma ascites cells with bleomycin A2, in vivo as well as in vitro, in varying doses produced marked alterations in nucleolar and cytoplasmic ultrastructural organization. A series of changes occur including formation of fibrillar centers, fragmentation of fibrillar nucleolar elements, appearance of microspherules, and the loss of fibrillar elements from these nucleoli. A bleomycin concentration of 10 mug/ml in vitro produced an increased number of fibrillar centers with well-defined nucleolonemas. At a concentration of 50 mug/ml, there was an increase in number and fragmentation of these fibrillar centers and many microspherules were found throughout the nucleolus. Approximately one-fourth of the cells contained cytoplasmic fibrillar bodies and amorphous fibrous tufts around the nuclear envelope. At a bleomycin concentration of 100 mug/ml, the nucleoli contained more granular elements and numerous microspherules. Almost 90% of the cells contained cytoplasmic fibrillar bodies. The effects of bleomycin in vivo (10 mg/kg) closely resemble those found in vitro with concentrations of 50 and 100 mug/ml.

Animals↗