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Biomedical subjects

J E Gill

Publications and source records attributed to J E Gill.

11 recordsLinked to original sources
PubMed1979

Laboratory test of seven rodenticides for the control of Mastomys natalensis.

Laboratory feeding tests were carried out to assess the efficacy of seven rodenticides against Mastomys natalensis. The poisons (warfarin, coumatetralyl, difenacoum, brodifacoum, bromadiolone, calciferol and zinc phosphide) were all toxic at the concentrations normally used against Rattus norvegicus (Berk.), although several were unpalatable. Trials are now needed to demonstrate the relative efficacy of these poisons in the field, but it is likely that, given suitable bait formulations, they would all be useful as practical control agents.

4-Hydroxycoumarins↗
PubMed1979

Cytofluorometric and cytochemical comparisons of normal and abnormal human cells from the female genital tract.

Acridine orange staining of exfoliated cells from epithelial tissues facilitates discrimination between normal and abnormal cells: abnormal cells develop highly elevated nuclear fluorescence. Comparisons of acridine orange (AO) staining with propidium iodide (PI) or Feulgen staining have shown that: (a) PI staining also provides highly elevated nuclear fluorescence from abnormal cells; (b) the distributions of nuclear fluorescence following AO or PI staining were usually not significantly different as judged by the Kolmogorov-Smirnov test; (c) fluorescence emission spectra from AO and PI stained cells are consistent with the hypothesis that both fluorochromes bind to DNA within cell nuclei; (d) DNAse treatment of AO stained normal cells eliminates the nuclear fluorescence peak from slit-scan contours; RNAse treatment has no effect on nuclear fluorescence; (e) the distribution of abnormal cell nuclear fluorescence after AO staining is usually, but not always, significantly different from the distribution of abnormal cell nuclear absorbance after Feulgen staining, with relative nuclear fluorescence being greater than relative nuclear absorbance. The hypothesis currently most consistent with these results is that elevated Feulgen DNA content can account for only part of the discrimination provided by AO staining, and that the chromatin within abnormal cells is altered so as to increase accessibility of DNA to intercalating dyes.

Cell Nucleus↗
PubMed1979

Warfarin-resistance genotype determination in the Norway rat, Rattus norvegicus.

The 2-stage determination is based on changes in blood coaggulation activity brought about both by the administration of warfarin in conjunction with vitamin K1 epoxide and by feeding a vitamin K-free diet for 4 days. When it was applied to laboratory-bred rats of known warfarin-resistance genotype, 35/35 homozygous susceptible, 44/44 homozygous resistant and 131/133 heterozygous rats were correctly classified. This method was equally effective in identifying the genotype of wild rats carrying the warfarin-resistance gene, Rw2. The procedure is rapid and accurate.

Animals↗
PubMed1978

The development and use of a test to identify resistance to the anticoagulant difenacoum in the Norway rat (Rattus norvegicus).

Feeding tests were carried out in the laboratory to obtain basic data on the susceptibility of wild Norway rats to difenacoum. The results were used to derive a standard test procedure for the identification of difenacoum resistance in warfarin-susceptible and resistant rats. Details are given of tests on rats from suspected difenacoum-resistant infestations on farms.

4-Hydroxycoumarins↗
PubMed1978

A comparison of acridine orange and Feulgen cytochemistry of human tumor cell nuclei.

Specimens of cells derived from tumors of the human female genital tract plus normal cells as standards have been divided into aliquots and stained according to acridine orange or pararosanilin:Feulgen procedures. Acridine orange-stained cells were slit-scanned for 535 nm nuclear fluorescence; Feulgen-stained cells were comb-scanned for 580 nm nuclear absorbance. For each specimen examined, the tumor cell:normal cell ratio of mean nuclear fluorescence following acridine orange staining was greater than the tumor cell:normal cell ratio of mean nuclear absorbance following Feulgen staining. The tumor cell:normal cell ratio of mean nuclear fluorescence ranged from 2.3 for a nonkeratinizing squamous cell carcinoma to 3.9 for a keratinizing squamous cell carcinoma. The tumor cell:normal cell ratio of mean nuclear absorbance ranged from 1.4 for a mixed mesodermal sarcoma to 2.3 for a small cell squamous cell carcinoma. These results indicate that the elevated nuclear fluorescence intensity from acridine orange-stained tumor cells cannot be explained solely on the basis of elevated Feulgen:DNA content. An alternative hypothesis, consistent with these results, is that DNA is the principal binding substrate for intranuclear acridine orange and that the DNA of certain tumor cells is more accessible to acridine orange than is the DNA of normal cells.

Acridines↗
PubMed1976

Further observations on the chemistry of pararosaniline-Feulgen staining.

Pararosaniline-Feulgen staining of cells in suspension produces nucleus- and chromatin-specific fluorescence as well as color. Experiments were designed to test postulated reaction mechanisms responsible for the fluorescent staining with the nonfluorescent pararosaniline. The reduction in fluorescent-staining intensity by pretreatment of cells with 2.2 x 10-2M K2S2O5 tends to rule out the alkysulfonic acid pathway; conditions favoring the formation of this intermediate reduce staining intensity. The fluorescence enhancement, observed when cells stained in pararosaniline without K2S2O5 are post-treated with K2S2O5, suggests that there is an initial Schiff-base linkage between pararosaniline and an aldehyde of hydrolyzed DNA, and that this linkage is stabilized in the presence of K2S2O5. Microspectrofluorometer measurements of cells stained at various pararosaniline concentrations in 2.2x10-2M K2S2O5, show that the fluorescence emission maximum ranges from about 627 nm at 3.1x10-3 M pararosaniline to about 604 nm at 3.1x10-5M. All of the employed staining protocols appear to produce the same fluorescent product, perhaps a heterocyclic pyronin analog formed from pararosaniline. Flow microfluorometric analysis of cells stained in suspension verified that the relative fluorescence intensity represents relative DNA content. Staining at reduced pararosaniline concentration (3.1x10-4M) reduces the coefficient of variation of the flow microfluorometric histograms, showing that maximum quantitation does not necessarily correlate with maximum staining intensity.

Animals↗
PubMed1976

Laboratory evaluation of WBA 8119 as a rodenticide for use against warfarin-resistant and non-resistant rats and mice.

Feeding tests were carried out in the laboratory to evaluate WBA 8119 as a potential new rodenticide against wild common rats (Rattus norvegicus), ship rats (R. rattus) and house mice (Mus musculus). The results obtained are compared with data previously obtained for difenacoum, another member of the same series of 4-hydroxycoumarin anticoagulants. With warfarin-resistnat and non-resistant common rats, complete kills were obtained using a concentration of 0-0005% for 2 days, or 0-001% for 1 day: a 1-day test at 0-0005% killed 6 out of 10 and 17 out of 20 of the two types respectively. At 0-0005% complete kills of resistant ship rats were obtained after 2 days exposure and of resistant house mice after 1 day, but at 0-002% for 2 days there was some survival. Non-resistant ship rats and house mice were all killed after 2 days feeding on 0-002% bait. In 2-day palatability tests, R. norvegicus showed no significant aversion to the poison at 0-002% and 100% mortality was obtained. The poison was significantly unpalatable to R. rattus at 0-005% and to M. musculus at 0-005% and 0-002%, although with the last species these concentrations gave complete kills. It is concluded that WBA 8119 has greater activity than other known anticoagulants against the three commensal species examined. The laboratory results suggest that concentrations between 0-0005% and 0-002% would be suitable for field use against common rats, and between 0-002% and 0-005% for ship rats and house mice.

4-Hydroxycoumarins↗
PubMed1976

A new optical multichannel microspectrofluorometer.

A new microspectrofluorometer has been developed that combines a photometric fluorescence microscope with an optical multichannel analyzer. This instrument provides fluorescence emission spectra of biological materials by detecting the entire spectrum simultaneously in real time. These spectra are subsequently recorded and corrected so as to identify the fluorescent reaction products or to test whether fluorescent cytochemical probes bind to the expected substrate within cells. The procedures and advantages of optical multichannel analysis are described, and an application of microspectrofluorometry to acriflavine-Feulgen cytochemistry is given.

Autoanalysis↗
PubMed1975

7-Amino-actinomycin D as a cytochemical probe. I. Spectral properties.

The optical absorption and fluorescence characteristics of 7-animo-actinomycin D were determined to evaluate its potential as a fluorescent cytochemical probe. At pH 7.0, the absorption maximum and fluorescence excitation maximum are both at 503 nm; the fluorescence emission is at 675 nm. When this compound forms complexes with DNA in solution, the absorption and fluorescence excitation maxima shift to 543 nm and the fluorescence emission shifts to 655 nm. The fluorescence quantum yield is 0.016 for 7-amino-actinomycin D free in solution and 0.01-0.02 for complexes with native DNA. The 7-amino-actinomycin D also exhibits fluorescence shifts characteristic of binding when put into solution with poly(dG-dC) poly(dG-dC), but not with poly(dI-dC) poly(dI-dC). The spectral characteristics are the same at pH 7.0 whether the solvent is 0.01 M PO4 with 0.0001 M EDTA or Earle's salts with 0.025 M N-2-hydroxyethylpiperazine-N1-2-ethanesulfonic acid.

Animals↗