Blood flow measurements with radionuclide-labeled particles.

Inhibition of DNA methyltransferase and induction of Friend erythroleukemia cell differentiation by 5-azacytidine and 5-aza-2'-deoxycytidine.

Acute ethanol administration (3 g/kg twice a day) to pregnant mice, from the 9th thru the 11th day of gestation, resulted in hypomethylation of fetal deoxyribonucleic acid (DNA) Nuclei isolated from the fetuses of the ethanol-treated mice had lower levels of methylase activity relative to controls even in the presence of excess S-adenosylmethionine, which serves as the methyl donor for the enzyme DNA methyltransferase Acetaldehyde, at concentrations as low as 3 to 10 microM, inhibited DNA methyltransferase activity in vitro Since DNA methylation is thought to play an important role in the regulation of gene expression during embryogenesis, ethanol-associated alterations in fetal DNA methylation may contribute to the developmental abnormalities seen in the fetal alcohol syndrome

Ethanol consumption inhibits fetal DNA methylation in mice: implications for the fetal alcohol syndrome.

In recent years, tumor-related angiogenesis has become an important field of research in oncology. It could be stated that growth of solid tumors is completely dependent on neovascularization to provide the tumor with all required nutrients. Special compounds (tumor angiogenesis factor[s]) are released by tumor cells into the environment to stimulate different types of normal cells to become active for the tumor. In particular, endothelial cells of neighboring capillaries are induced to react. They disintegrate their own basal lamina, detach from their neighbors, enter the extracellular matrix, and migrate toward the tumor mass. Cell divisions occur within such sprouts, thereby increasing the number of migrating endothelial cells. Strands of such cells are formed, and inter- and intracellular lumina develop. Loops of these hollow strands anastomose to form a network of new vessels which become connected with the blood circulation. The tumor mass thus becomes vascularized and can continue to grow. The prevention of neoangiogenesis has an enormous impact on cancer treatment by inhibiting the growth of the tumor. In this review, all important aspects of tumor-related angiogenesis are presented.

Tumor-related angiogenesis

Abstruct-The differential blood flow rateof normaland tumor tissues plays a critical role in determining the effectiveness of hyperthermia alone or in combination with radiation and chemotherapy. The objective of this paper is to summarize the data on tumor blood flow rate during normothermia and hyperthermia, and to discuss the use of pharmacological agents in modifying the tumor blood flow rate for therapeutic benefits. After a brief review of various physical, physiological, biochemical, and biological factors that determine the effectiveness of hyperthermia in cancer treatment, various methods of blood flow measurements will be outlined. The following section will be devoted to the tumor blood flow rate during normothermia. Next will be discussion of changes in tumor blood flow rate at elevated temperatures. Finally, the possibility of modifying tumor blood flow rate by the use of vasoactive agents will be discussed. Throughout this paper, outstanding problems in the measurements and alterations of blood flow will be identified and some directions for future research will be suggested.

Tumor Blood Flow-Characterization, Modifications, and Role in Hyperthermia

The determination of regional blood flow and cardiac output with radioactively labeled microspheres and a reference arterial sample has been assessed in the rabbit. Paired determinations of cardiac output with the microsphere and indocyanine green dye dilution methods correlated well (F=236; p

A simple radioactive microsphere method for measuring regional flow and cardiac output.

Since HeLa cells are one of the most commonly studied established cell lines, there is a need for a simple and rapid method for isolating enzymatically active cell nuclei which are not aggregated and thus can be pipetted in reproducible aliquots . We report here such a procedure which may be used for both large and small volumes of suspension cultures and which requires no specialized equipment. The method is a modification of previous techniques (1-3), all of which are based upon the use of Triton detergents . Although several other procedures for isolating HeLa cell nuclei have been published (4-7), the convenience and utility of the present method warrant consideration .

https://rupress.org/jcb/article-pdf/42/3/851/1069254/851.pdf

A simple and rapid method for the isolation of enzymatically active HeLa cell nuclei.

Exoribonuclease purified from Ehrlich ascites tumor cell nuclei and in intact HeLa cell nuclei is irreversibly inactivated by tow concentrations of p-bromo- and p-iodoacetamidophenyl nucleotides and by thymidine-39-fluorophosphate. Iodoacetate, bromoacetate, and thymidine-59-fluorophosphate do not affect the enzyme. Although p-haloacetamidophenyl nucleotides inactivate ribonucleic acid polymerase of isolated HeLa cell nuclei, thymidine-39-fluorophosphate does not affect the activity of this enzyme in vitro.

Irreversible Inhibition of Nuclear Exoribonuclease by Thymidine-3'-Fluorophosphate and p-Haloacetamidophenyl Nucleotides

Blood flow determinations and arteriograms were obtained in rat (Walker carcinoma) and rabbit (V2 carcinoma) liver tumors at rest and after norepinephrine administration. Resting tumor blood flow exceeded resting hepatic flow in both models, and both tumors responded with vasoconstriction and reduced blood flow. In tumors and the surrounding normal host tissue, the greater the perfusion prior to drug administration, the greater is the response (decrease in perfusion) to the vasoconstrictor. Although tumor perfusion decreased after vasoconstrictor, post-norepinephrine angiograms revealed an improved diagnostic image because of the enlarged but unresponsive tumor feeder vessels, persistent tumor blush, and simultaneous vasoconstriction in the normal liver. In these models, improved tumor visualization resulted even though a decrease in tumor blood flow had occurred. The angiographic image is related therefore to the lack of vasoconstriction in the tumor feeder vessel, which has, however, a decreased blood flow and the correspondingly greater volume of normally constricting hepatic arteries which results in a marked decrease in the background of vessels upon which the tumor image is superimposed.

Resting host and tumor perfusion as determinants of tumor vascular responses to norepinephrine.

Summary A simple method for the isolation of nuclei from tracheal epithelial cells is described. The isolated nuclei are morphologically well preserved and can be suspended in reproducible aliquots. RNA polymerase and exoribonuclease activity can be measured in the isolated nuclei.

https://cancerres.aacrjournals.org/content/canres/31/2/199.full.pdf

Daniel M. Berkowitz

Papers

A simple radioactive microsphere method for measuring regional flow and cardiac output.

A simple and rapid method for the isolation of enzymatically active HeLa cell nuclei.

Irreversible Inhibition of Nuclear Exoribonuclease by Thymidine-3'-Fluorophosphate and p-Haloacetamidophenyl Nucleotides

Resting host and tumor perfusion as determinants of tumor vascular responses to norepinephrine.

Isolation of Enzymatically Active Nuclei from Epithelial Cells of the Trachea