Showing papers in "Chemico-Biological Interactions in 1975"

TL;DR: It appears that this model can be used to detect a carcinogenic or co-carcinogenic potential in compounds which are organotropic for the bladder more rapidly and with fewer animals than if the compounds are tested as solitary carcinogens by more conventional methods.

TL;DR: A number of complexes of platinum(II) and platinum(IV) have been prepared, characterised and tested for their ability to cause regression of a mouse plasma cell tumour.

TL;DR: The effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin on a number of hepatic and extrahepatic foreign-compound-metabolizing enzyme systems in microsomes from rats, rabbits and guinea pigs were investigated and the inductive effect on rat hepatic microsomal enzymes was considerably more persistent than the suppressive effect.

TL;DR: The response of a patient with histologically proven reticulum cell sarcoma to no treatment other than large doses of ascorbic acid is described and the significance of the therapeutic response is briefly discussed in relation to general schemes of cancer management.

TL;DR: Cells of a line (K7), derived from the cortex of the adult pig kidney, synthesize and accumulate high levels of metallothionein when grown in vitro in the presence of low concentrations of Cd2+.

TL;DR: The main eliminative route for [14C]vinyl chloride after oral, i.

TL;DR: The results of these studies have indicated that the decrease in the activity of the hepatic mixed-function oxidase enzyme system and the concentration of cytochrome P-450 seen on incubation of carbon disulfide (CS2) with rat liver microsomes in the presence of NADPH is the result of the binding of the sulfur atom released in the mixed- function oxidase catalyzed metabolism of CS2 to carbonyl sulfide (COS).

TL;DR: A single injection of dimethylnitrosamine (DMN) induced hepatocellular carcinoma in rats and no tumors developed when another alkylating carcinogen, methyl methanesulphonate (MMS), was administered after partial hepatectomy; the significance of these results in relation to the mechanism of initiation of carcinogenesis is discussed.

TL;DR: Testing as mutagens for strains of Salmonella typhimurium carrying the hisG46 missense mutation suggests that each drug interacts with DNA by a different mechanism, and cis-PtCl2(NH3)2 is more active on the latter, while the converse is true for RuCl2 (DMSO)4.

TL;DR: The much higher binding of AFB1 to nucleic acids than to protein might account for the potent carcinogenicity of this compound in the rat, particularly since liver protein binding does not differ between a susceptible and a resistant species.

TL;DR: Foster mother experiments demonstrated that the postnatal inductive effect resulted both from exposure of newborns to TCDD via maternal milk and the activation of an inducing mechanism occurring after birth and multiple factors are responsible for the induction of hepatic microsomal enzymes in the newborn.

TL;DR: Female 6-8-week-old mice were injected with N-methyl-N-nitrosourea in saline and DNA was isolated from bone marrow, small bowel, kidneys, liver, lungs, spleen and thymus and by analyses using column or paper chromatography of DNA hydrolysates, the extent of methylation of DNA purines was determined.

TL;DR: The experiments described support the concept that replication of DNA containing bases which are likely to mispair during replication may be necessary to 'fix' the lesion and thus cause a permanent inheritable change in the genetic material.

TL;DR: The results suggest that cis Pt(IV) may be activated cellularly and that cross-linking is not the primary mechanism of action of the tumor-inhibitory platinum compounds.

TL;DR: The antimitotic action of the pyrrolizidine alkaloid lasiocarpine on rat liver parenchyma was investigated using as the experimental model the wave of mitosis produced in liver by a single dose of thioacetamide, finding the location of the mitotic block to be either in the latter half of the DNA synthetic phase, S, or early in G2, the post-synthetic phase.

TL;DR: The reaction characteristics of chlorothalonil with glyceraldehyde-3-phosphate dehydrogenase (GPDH) and trichloromethyl fulfenyl fungicides with GPDH were studied in vitro and it was suggested that the differences in reaction rates of the fungicides are due to the molecular size and the chemical nature of the reactive toxiphores.

TL;DR: It is found that dimethylnitrosamine leads to strand breaks in mitochondrial DNA and the possible use of this system to investigate carcinogen-induced breaks in DNA is discussed.

TL;DR: TPA did not inhibit "post-replication repair" in response to UV irradiation of growing Chinese hamster cells, and both TPA and PDB did cause rapid dramatic increases in cyclic guanosine monophosphate levels in human amnion cells; phorbol had no effect.

TL;DR: The data indicate that liver microsomes from untreated rats and mice contain more than one cytochrome P-450 and that of these cytochromes may be located in different parts of the endoplasmic reticulum.

TL;DR: All five alkylating agents increased the excretion of 1-methyl-nicotinamide (1-meNmd) and a larger quantity of 7-methylguanine (7MG) and uric acid was excreted after DMN treatment.

TL;DR: After in vivo administration of N,N-di[14C]methylnitrosamine, the amount of alkylation in DNA was found to be lower in the polylysine-binding regions, suggesting a heterogeneous distribution of these regions.

TL;DR: Under the conditions of low speed centrifugation used in this study, the proportion of radioactively labelled DNA from Chinese hamster V79-379A cells sedimenting to the 700S region of an alkaline sucrose gradient was increased in a dose-dependent manner by prior treatment of the cells for 2 h with cis-platinum (II) diamminedichloride.

TL;DR: In larvicide tests with four mycotoxins, aflatoxin B1 was most toxic to Drosophila melanogaster, followed by rubratoxin B and diacetoxyscirpenol, which had strong insecticidal activities.

TL;DR: The differences between chromtin of stimulated and chromatin of unstimulated cells are abolised when bother chromatins are treated with 0.25 M NaCL.

TL;DR: Young adult inbred Swiss mice given single or repeated equitoxic doses of N-methyl-N-nitrosourea or methyl methanesulphonate develop thymomas and pulmonary adenomas only following MNUA in spite of nearly identical overall alkylation of DNA of tumour target tissues by both agents due mainly to the biologically ineffective product 7-methylguanine.

TL;DR: Brief exposure to beta-propiolactone (BPL) increases the sedimentation rate of purified Escherichia coli DNA in neutral and alkaline sucrose gradients, but when electrophoresed in polyacrylamide-agarose gels, this BPL-treated DNA moves ahead of the control.

TL;DR: Enhancement of the activity by ferrous ions and FAD indicated that at least part of the reduction system could involve a flavoprotein with FAD as the prosthetic group.