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Biomedical subjects

I A Bernstein

Publications and source records attributed to I A Bernstein.

80 records · Page 5Linked to original sources
PubMed1968

Adenosine triphosphate and synchronous mitosis in Physarum polycephalum.

Synchronous mitoses occur in Physarum polycephalum in the absence of cell division. Nucleoside and nucleotide profiles were prepared from synchronously growing P. polycephalum at intervals throughout the growth cycle. Comparison of these profiles demonstrates that the pool of adenosine triphosphate decreases from a high level at prophase to a minimum through mitosis and increases again in the postmitotic period. These events appear to coincide with changes in the pools of adenosine diphosphate and adenosine but not with that of adenosine monophosphate. This observed decrease in the pool of adenosine triphosphate during mitosis was confirmed by direct enzymatic assay. These results presumably reflect the energy demands of the cell during mitosis.

Adenine Nucleotides↗
PubMedDate not supplied

Appearance of interleukin 1 alpha relates DNA interstrand cross-links and cytotoxicity in cultured human keratinocytes exposed to bis-(2-chloroethyl) sulfide.

The utility of an increase in the level of interleukin 1 alpha (IL-1 alpha) as an indicator of cytotoxicity from exposure to bis-(2-chloroethyl) sulfide (BCES) was evaluated in submerged monolayer cultures of human cutaneous keratinocytes. Four-day-old cultures were exposed to 1-100 microM BCES at 37 degrees for 30 min. The amounts of IL-1 alpha in the medium at and in cells 72 h after exposure were measured immunologically with an enzyme-linked immunosorbent assay using monoclonal antibody to human IL-1 alpha. The antibody was conjugated with peroxidase for visualization. Cell viability was measured concomitantly using the trypan blue exclusion technique. The degree of interstrand cross-linking as a measure of damage in the cellular DNA was determined by measuring the fluorescence resulting from the intercalation of ethidium bromide into double-stranded molecules that remained in heat-denatured DNA isolated from cells that had been exposed to BCES. A high correlation was observed between the dose-responsive increase in the level of IL-1 alpha in the medium and in the cells, and the dose-responsive decrease that took place in the fraction of viable cells in exposed cultures. The dose-responsive increase in the interstrand cross-linking found in the DNA of cells immediately after exposure to BCES also correlated with the increase in IL-1 alpha 72 h after exposure. These data suggest that the appearance of IL-1 alpha can be used to quantify the cytotoxicity resulting from BCES-medicated damage to cellular DNA and that degree of cross-linking in the DNA immediately after exposure to BCES is predictive of the level of cytotoxicity in an exposed culture 3 days later.

Cell Survival↗
PubMedDate not supplied

Cultured keratinocytes in in vitro dermatotoxicological investigation: a review.

The keratinocyte is responsible for the architecture of the epidermis, that portion of the skin that forms the environmental barrier necessary for survival. It also interacts with other cell types in the epidermis in response to various environmental influences. This cell type is used frequently for in vitro cutaneous toxicological investigations as an alternative to whole-animal studies. Several areas of cutaneous research using cultured keratinocytes are germane as regards the scope of this journal. The following areas of biomedical research were reviewed: (1) dermatotoxicology, including environmental chemicals, antiseptics, drugs, metals, and pesticides; (2) immunotoxicology, including inflammation and allergic dermatitis; (3) radiation, including ultraviolet and x-irradiation; and (4) the development of assays as alternatives to whole-animal testing. Due to the abundance of such investigations reported in the last 30 years, this review is limited mainly to reviewing reports published in this decade.

Animals↗