Biomedical subjects
D Wild
Publications and source records attributed to D Wild.
Cytogenetic effect of ortho-phenylenediamine in the mouse, Chinese hamster, and guinea pig and of derivatives, evaluated by the micronucleus test.
The mutagenic potential of ortho-phenylenediamine--known by studies on Salmonella typhimurium--was studied in mice, Chinese hamsters and Guinea pigs with the use of the micronucleus test. In bone marrow of all three species, chromosomal damage was detected following intraperitoneal injections of the test chemical, this damage was seen also after peroral administration to mice. Four derivatives of ortho-phenylenediamine containing one or two methyl-, nitro- or chlorosubstituents in 4- or 5-position of the aromatic ring were studied in mice. Of these the 4-methyl-derivative induced micronuclei, the 4-nitro-, 4,5-dimethyl-, and 4,5-dichloroderivatives were inactive. The results indicate that the chemical nature and the number of substituents influence the chromosome damaging potential.
Mutagenicity study of Remsen-Fahlberg saccharin and contaminants.
Saccharin and contaminants of commercial Remsen-Fahlberg saccharin were studied for mutagenic potential with the use of the Salmonella/microsome test, Basc-test in Drosophila melanogaster and micronucleus test in mice. In none of these tests were mutagenic effects of saccharin observed. Likewise, the ortho- and para-sulfamoylbenzoic acids (OSBA and PSBA) were ineffective. Para-toluenesulfonamide (PTS) and the major contaminant ortho-toluene-sulfonamide (OTS) exhibited weak mutagenic effects in a modified Salmonella/microsome test and in Drosophila. These results do not indicate mutagenic and therewith correlated carcinogenic potential of saccharin, but they emphasize the possible activity of contaminants.
Transplacental mutagenesis: the micronucleus test on fetal mouse blood.
The induction of cytogenetic damage (micronuclei) in mouse fetal blood was studied with four selected mutagens: cyclophosphamide, procarbazine, trenimon, and mitomycin-C. For comparison the standard micronucleus test on maternal bone marrow was also performed. In contrast to the results obtained from maternal bone marrow the changes in the cellular composition in fetal blood were only slight after treatment with mutagens. A significant and dose-dependent increase in the incidence of micronucleated fetal blood cells was found with all four mutagens. The inducibility of micronuclei by indirect mutagens was particularly interesting. The three mutagens other than mitomycin-C induced a higher frequency of micronucleated polychromatic erythrocytes in fetal blood cells than in maternal bone marrow. The results indicate that this modified micronucleus test is well suited and useful for mutagenicity screening of environmental chemicals and especially for assessment of risks to the fetus when pregnant females are exposed to environmental chemicals.
Supply and demand in the NHS.
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Mutagenicity studies with x-ray-contrast media, analgesics, antipyretics, antirheumatics and some other pharmaceutical drugs in bacterial, Drosophila and mammalian test systems.
As part of our investigation into mutagenic effects of environmental compounds, we studied 21 pharmaceuticals most frequently sold in West Germany: 6 X-ray-contrast media, 13 analgesics, antipyretics and antirheumatics, 1 central stimulant, and 1 antidepressant. They were studied in different bacterial, Drosophila and mammalian test systems. 4 of these 21 compounds could be detected as mutagens in one of the test systems. namely: 1,2-dichloroethane induced an increase in the frequency of recessive sex-linked lethal mutations in Drosophila melanogaster, quinine dihydrochloride and dimethylaminophenazone were mutagenic in the Salmonella typhimurium tester strain TA98 in the presence of S-9 liver fraction derived from Aroclor-induced rats, and trilithium citrate caused a significant effect in the micronucleus test on bone marrow of NMRI mice.
The Royal Commission on the NHS. Teams and plans and misused terms.
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[Bacterial studies also suitable for carcinogenic tests].
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Fibreoptic gastroscopy in dolphins.
Diseases of the upper gastrointestinal tract, including ulceration, infection, parasitism and the effects of ingested foreign bodies are common in captive dolphins. Using a fibreoptic colonoscope, techniques were devised for examination of the oesophagus and stomach and the removal of foreign bodies.
Cytogenetic effects in the mouse of 17 chemical mutagens and carcinogens evaluated by the micronucleus test.
2 dialkylnitrosamines, 4 oxazaphosphorines, 6 aryldialkyltriazenes, urethane, N-hydroxyurethane, 4-nitroquinoline-1-oxide, procarbazine (natulan) and the inorganic carcinogen potassium chromate were studied for cytogenetic activity in the micronucleus test on mouse bone marrow. Except diethylnitrosamine, all chemicals were active. The results are compared with those known from studies in other mammalian and sub-mammalian test systems. The results of the micro nucleus test correlate well with results from other mutagenicity tests and with the carcinogenicity of the chemicals. The lack of an effect on N-nitrosodiethylamine (DENA) is discussed with regard to the short life-time of the ultimate mutagen.
Comparative in vivo mutagenicity testing by SCE and micronucleus induction in mouse bone marrow.
The treatment of mice with repeated injections of BUdR and FUdR allows for the demonstration of differentially stained metaphases from bone marrow after FPG (fluorescence plus Giemsa; Perry and Wolff, 1974) treatment. Thus, it is possible to determine the number of SCE's under in vivo conditions, which appears as a very promising system for mutagenicity testing. We studied the response of this system in comparison to the micronucleus test using six mutagenic agents: triaziquone, cyclophosphamide (CP), dimethylphenyltriazene (PDMT), methylnitronitrosoguandine (MNNG), dimethylnitrosamine (DMNA), and diethylnitrosamine (DENA). With the exception of MNNG and DENA, all these agents induce both, SCE and micronuclei, MNNG and and DENA being ineffective in both systems. The most potent SCE-inducing agent was triaziquone, followed by PDMT, CP, and DMNA. The quantitative comparison indicates that SCE are induced at 1/10-1/100 of the concentrations which are required for the detection of micronuclei.
Isolation of mammalian cell mutants deficient in glucose 6-phosphate dehydrogenase by means of a replica-plating technique.
A replica-plating technique is described which was used for the isolation of G-6-PD-deficient mutants in cultures of mutagen-treated Chinese hamster cells. Mutants were recognized by their failure to stain in a histochemical G-6-PD-specific staining reaction. Four mutants were isolated and characterized by growth properties, stability of their variant phenotypes, and reduced G-6-PD activity. One of these mutants on electrophoresis exhibited a variant G-6-PD and thus is very likely the result of a mutation in the structural gene for G-6-PD.
Hospital administration--the new order; the medical administrator's point of view.
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Mutagenicity studies on organophosphorus insecticides.
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Mutagenicity of the food additive AF-2, a nitrofuran, in Escherichia coli and Chinese hamster cells in culture.
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Serum effect on the yield of chemically induced 8-azaguanine-resistant mutants in Chinese hamster cell cultures.
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Chemical induction of streptomycin-resistant mutations in Escherichia coli. Dose and mutagenic effects of dichlorvos and methyl methanesulfonate.
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Baby battering and its prevention.
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