Bertrum Sheid

Angiogenic effects of macrophages isolated from ascitic fluid aspirated from women with advanced ovarian cancer

The cellular components of ascitic fluid aspirated from the peritoneal cavity of women with advanced ovarian cancer were separated on a Ficoll gradient. Isolated macrophages, which were further purified, elaborated a growth factor which was mitogenic for human endothelial cells isolated from umbilical veins, arteries and the omental microvasculature in vitro, and was angiogenic in vivo. It is postulated that the macrophage-derived factor enhances tumor neovascularization of the widespread ovarian-derived peritoneal malignant lesions appearing in these patients, thus contributing to their rapid growth and metastasis, and the poor prognosis of the disease.

Inhibition of transfer RNA methylases by bull semen: I. Localization, identification and properties of the inhibitor

Abstract A potent tRNA methylase inhibitor has been identified in bull sperm and seminal plasma. A 1:2500 dilution of sperm containing 20 μg of protein was capable of inhibiting 100% rat liver tRNA methylase activity (10 mg of protein). Seminal plasma diluted 1:5000 (37.5 μg protein) was also able to totally inhibit the rat liver tRNA methylase activity. The inhibitory substance did not appear to function by degrading either of the substrates used in the assay; Escherichia coli tRNA and S-adenosylmethionine, the active methyl donor. The inhibitor had no effect on DNA methylase phenylethanolamine N-methyltransferase, and catechol O-methyltransferase activities, but did inhibit low levels of rRNA methylase activity. Various enzymatic, chemical and physicochemical methods were used to identify the inhibitor as a polysaccharide.

Inhibition of lymphocyte mitogenesis by factor(s) released from macrophages isolated from ascitic fluid of advanced ovarian cancer patients

SummaryAscitic fluid from women with advanced ovarian carcinomas was shown to contain factor(s) which inhibit(s) T lymphocyte mitogenesis. The factor(s) was (were) demonstrated to be associated with the infiltrating macrophages. The inhibition was reversible and inhibited mitogenesis at some late event in the cell cycle. The inhibitory substance(s) was (were) noncytotoxic, dialyzable, heat-stable at 70° C for 10 min (but unstable at 100° C for 15 min), and partially resistant to protease treatment (55%–70%). Further experiments demonstrated that macrophages isolated from the ascitic fluid of patients with cirrhosis of the liver also released factor(s) which inhibit(s) T lymphocyte mitogenesis. On the basis of our data and data from other investigators, we propose that in advanced human ovarian cancer of epithelial origin, macrophages which infiltrate the ascitic fluid elaborate nonspecific inhibitors of T lymphocyte blastogenesis within the proximal environment, resulting in localized immunosuppression and the subsequent enhancement of metastasis within the peritoneal cavity, the tumor cells themselves being resistant to the cytocidal action of the macrophages due to genetic selection and/or their inherent biochemical ability to circumvent normal immunosurveillance mechanisms. This may account, at least in part, for the rapid metastasis and poor prognosis of human ovarian adenocarcinomas.

Transfer RNA methylase activity and polyamine concentrations in regenerating rat liver.

Abstract The specific activity and tRNA methylating capacity of liver tRNA methylases were shown to remain constant during rat liver regeneration from 30 min through 7 days. During this identical time period there was a steady enhancement in the polyamine content of the same liver samples, reaching a 3-fold increase by the third day. These data suggest that polyamines, known in vitro stimulators of the tRNA methylases, are not involved in the in vivo regulation of the tRNA methylases.

Characterization of ellipticine binding to native calf thymus DNA.

The binding of [14C]ellipticine to native calf thymus DNA was studied using equilibrium dialysis. A Scatchard polt revealed the presence of high-and low-affinity binding sites in DNA, the former having a K of 4.0 X 10(7) M(-1) and an n (saturation limiting of binding) of 0.078 (1mol ellipticine/13 mol of DNA nucleotides). The forces involved in stabilizing the high-affinity binding, which has been equated with intercalative binding, were due to a combination of hydrophobic interactions and hydrogen bonding. Difference spectra of ellipticine in the presence of the polydeoxynucleotides, poly d(A-T) or poly d(G-C), showed that there was no base specificity involved in the high-affinity binding. Ellipticine binding to the low-affinity sites, which has been equated with surface binding, was due primarily to the participation of electrostatic interactions of ellipticine with the anionic phosphate groups on the double helical surface of DNA.

Single-stranded regions in DNA from pre- and postmenopausal human ovaries.

Abstract No differences were noted between the percent (2–4%) of single-stranded regions in DNA isolated from pre- and postmenopausal human ovaries as determined by nuclease S 1 digestion.

Transfer RNA methylase activity in normal and dystrophic chicken muscle

Abstract Adult-dystrophic chicken muscle had 30% higher tRNA methylase activity and 42% higher tRNA methylating capacity than normal-adult chicken muscle. Eighty percent of the tRNA methylase activity of the dystrophic muscle resulted in the synthesis of N 2 -methylguanine, and 9% in the formation of N 2 ,N 2 -dimethylguanine. From adult-normal muscle extracts, 33% of the tRNA methylase activity was due to the synthesis of N 2 -methylguanine, and 45% to the formation of N 2 ,N 2 -dimethylguanine. Eight other methylated bases accounted for 5–15% of the enzyme activity in both tissues. Dialyzed and nondialyzed adult-normal muscle extracts had equivalent tRNA methylase activity. However, the dialyzed extracts synthesized 22% more N 2 -methylguanine and 18% less N 2 ,N 2 -dimethylguanine than the nondialyzed extracts. Dialysis had no effect on the tRNA methylase activity or tRNA methylation pattern produced by adult-dystrophic muscle.

Non-enzymatic hydrolysis of transfer RNA by bull semen

Abstract Dilutions of deproteinized seminal plasma as low as 1:5000 were shown to contain sufficient amounts of a compound (s) which non-enzymatically hydrolyzed 0.1 mg tRNA into acid soluble fragments. Other evidence is presented to eliminate the possibility of the active seminal plasma substance (s) being ribonuclease contaminant (s).

Evidence for the existence of lactate dehydrogenase N in embryonic chick liver

Abstract Lactate dehydrogenase ( l -lactate:NAD oxidoreductase, EC 1.1.1.27) from embryonic chick liver had different kinetic and thermal stability properties from lactate dehydrogenase from adult chick liver, and lactate dehydrogenase prepared from different sources known to contain varying percentages of the lactate dehydrogenases 1, 2, 3, 4 and 5 isozymes. The embryonic chick liver lactate dehydrogenase could not be separated from adult chick liver lactate dehydrogenases or lactate dehydrogenase 5 on the basis of its electrophoretic mobility on polyacrylamide disc gels. However, embryonic chick liver lactate dehydrogenase utilized α-ketoglutaric acid as a substrate, and 3-acetylpyridine NAD as a coenzyme more efficiently than any of the other lactate dehydrogenase isozymes. Also embryonic chick liver lactate dehydrogenase was more resistant to heating at 65°C than the other lactate dehydrogenase isozymes. Further experiments showed that the kinetic properties of embryonic chick liver lactate dehydrogenase were consistent with those demonstrated for lactate dehydrogenase X.

Transfer RNA methylase activity in a pre-embryonic tissue.

Abstract 1. 1. Transfer RNA methylase specific activity of unfertilized Flounder roe was approximately 2-2·5 times higher than the enzyme activity from liver and intestine of young and adult fish. 2. 2. The increased activity in the roe was due to a N2,N2-dimethylguanine methylase which constituted 88% of the total roe methylase activity. 3. 3. There was a tRNA methylase inhibitor present in young and adult fish organs which was not demonstrable in the unfertilized roe.