Expression of antioxidant defense and poly(ADP-ribose) polymerase-1 in rat developing Sertoli cells.

Sertoli cells play an essential role in the development of a functional testis. ROS (reactive oxygen species) are normally produced by the developing testicular cells and may be dangerous to spermatogenesis. The aim of this study was to investigate the developmental expression of genes involved in antioxidant defense as well as in the DNA damage response in rat Sertoli cells.

A rapid method for detecting DNA strand breaks in Mytilus galloprovincialis Lam. induced by genotoxic xenobiotic chemicals.

1. In this study, DNA from haemolymph cells of Mytilus galloprovincialis Lam., as well as from L1210 (murine leukemia) mouse cells was investigated utilizing the technique of the alkaline unwinding of the double stranded DNA molecule.

Biochemical characterization of the DNA polymerase activity present in isolated nuclei from mussel tissues: a possible system for the evaluation of the rate of DNA repair.

1. The nuclear DNA polymerase activity in mussel digestive glands was characterized regarding Mg++ requirement (2 mM), ATP concentration (4 mM), pH (8.4), and ionic strength (50 mM).

Mechanism of action of a new prostaglandin antihypertensive, viprostol [CL 115 347; (dl)-15-deoxy-16-hydroxy-16(alpha/beta)-vinyl-prostaglandin E2 methyl ester]: (I). Vasodilation.

Viprostol [(dl)-15-deoxy-16-hydroxy-16(alpha/beta)-vinyl-prostaglandin E2 methyl ester; CL 115 347], injected directly into coronary, renal, mesenteric, femoral and carotid arteries of the anaesthetized beagle dogs at doses which did not lower the systemic arterial blood pressure, increased blood flow of the vascular beds being studied. Viprostol was as potent as I-prostaglandin E2 (I-PGE2) in the renal bed, but less potent in the other vascular beds. Viprostol was as potent as I-PGE2 in relaxing smooth muscle of the perfused isolated central ear artery of the rabbit.

Mechanism of action of a new prostaglandin antihypertensive, viprostol [CL 115 347; (dl)-15-deoxy-16-hydroxy-16(alpha/beta)-vinyl-prostaglandin E2 methyl ester]: (II). Effects on the adrenergic nervous system.

Viprostol [(dl)-15-deoxy-16-hydroxy-16(alpha/beta)-vinyl-prostaglandin E2 methyl ester; CL 115 347] is a new orally and transdermally active antihypertensive agent that exerts its major antihypertensive action by vasodilation. The present studies were conducted to examine its effects on the adrenergic nervous system. In cats, viprostol did not inhibit renal sympathetic nerve discharge (RSND) monitored at the postganglionic region, indicating that nerve transmission or conduction was not blocked at the ganglion or the pre- or postganglionic fibres.

Characteristics of the DNA polymerase beta-directed unscheduled DNA synthesis in isolated nuclei from adult rat liver.

Isolated nuclei from adult rat liver have been used as a model system to define several characteristics of the unscheduled DNA synthesis supported by DNA polymerase beta. Many of these characteristics have been found to reflect some catalytic properties (pH optimum, divalent cations requirement, dependence on all four deoxyribonucleoside triphosphates, apparent Km for dTTP) as well as sensitivity to various agents (differential inhibitors of eukaryotic DNA polymerases, phosphate, DNA intercalating drugs, chemical or thermal denaturation) commonly regarded as typical of DNA polymerase beta itself. Given the new picture of the enzymology of DNA repair synthesis which has recently emerged, none of the above characteristics seem to be suitable candidates as diagnostic tools of a repair polymerization process.

Antihypertensive activity of dl-15-deoxy-16-hydroxy-16(alpha/beta)-vinyl prostaglandin E2 methyl ester (CL 115,347), a new orally and transdermally long-acting antihypertensive agent.

CL 115,347 [dl-15-deoxy-16-hydroxy-16(alpha/beta)-vinyl prostaglandin E2 methyl ester] has a broad spectrum of antihypertensive activity in many animal hypertension models in every species tested. In conscious spontaneously hypertensive rats, CL 115,347 at 0.25 to 10 mg/kg orally produced 31 to 53 mm Hg lowering of the mean arterial blood pressure (MABP) with a duration of action of 1 to greater than 8 hr.

[Synthesis of RNA and DNA in isolated nuclei of Colpoda cucullus (Protozoi Ciliati)].

The ciliated protozoan Colpoda cucullus has been cultivated at 27 degrees C with gentle shaking in a baked lettuce infusion supplemented with Klebsiella suspensions. Under these conditions cells had a mean generation time of about 7 hours and could attain densities up to 20,000/ml and 45,000/ml in the log and stationary phase of growth, respectively. Nuclear preparations obtained from exponentially growing cells by the gum arabic-octanol method showed a satisfactory degree of purity and integrity.

Increased levels of rat liver RNA polymerase I(A) and I(B) following the administration of triiodothyronine.

The levels of the transcribing RNA polymerase I(B) in the nucleus and of the non-transcribing RNA polymerase I(A) in the cytoplasm are both approximately doubled 24 h after a single i.p. injection of triiodothyronine into thyroidectomized rats.

Inhibition of isolated rat liver RNApolymerases I and II by aminoacridines.

9-Aminoacridine and 2 derivatives which contain hydroxyalkylic or aminoalkylic side chains in the 9-position totally inhibit the transcription of calf thymus DNA by rat liver RNA polymerases I and II. This inhibitory action does not always appear to be completely related to the ability of aminoacridines to intercalate into the DNA template.

[Reduced catalytic effectiveness of RNA polymerase I in hepatocytes of rats treated with cycloheximide].

Rat liver RNA polymerase I solubilized from isolated nuclei and present in a soluble form in the cytoplasmic fraction has been analyzed by phosphocellulose chromatography 3 hours after the administration of cycloheximide. The antibiotic did not induce any change in the chromatographic properties of both nuclear and cytoplasmic RNA polymerase I. They appeared to remain in the IB and IA forms, characteristic of the transcribing (IB) and non-transscribing (IA) enzyme.

[Influence of temperature on the preferential extraction of RNA polymerase I from hepatic nuclei of the rat].

RNA polymerase I has been extracted from rat liver nuclei by three consecutive washings at 0 degrees C with a medium of relatively low ionic strength (0.15 M KCl) containing Mg++ rather than by incubating the organelles at 37 degrees C in the same medium, as originally proposed by Chesterton and Butterworth. The modified technique, which has the advantage of preventing a temperature-mediated conversion of form IB to IA, gives similar yields of RNA polymerase I and retains the capacity of preferentially extracting the enzyme with respect to the other forms of nuclear RNA polymerase.

Functional state of rat liver RNA polymerase IA and IB.

Phosphocellulose chromatography has been employed to characterize RNA polymerase I present in two different functional states in rat liver cells. The actively transcribing enzyme solubilized from nuclei appears to belong both to the IA and IB classes, whereas the non-transcribing enzyme present in the cytoplasmic fraction has been found to belong only to the IA class. Indirect and direct evidence indicates, however, that in isolated nuclei only the IB form is to be regarded as the physiological form of the enzyme, the IA form arising as a procedural artefact during the extraction process.

6-(14C)-orotate uptake and rna synthesis by liver from thyroidectomized rats treated with 3,5,3'-triiodo-1-thyronine (t3).

It has been shown that T3 administration to thyroidectomized rats induces a marked increase of the in vivo labelling of liver nuclear RNA by 6-[14C]-orotic acid and, although to a lesser extent, of the radioactivity of the acid-soluble fraction. Therefore, in evaluating the real increase in RNA synthesis induced by T3 administration it has been taken into account that the hormone stimulates the uptake of the labelled precursor by the liver and enhances the specific activity of the nucleoside and nucleotide pool. The greater penetration of orotate into the liver does not depend on the increased RNA synthesis since it is not prevented by the administration of actinomycin D which markedly inhibits the transcriptional process.