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Biomedical subjects

J Wilhelm

Publications and source records attributed to J Wilhelm.

At least 91 records · Page 5Linked to original sources
PubMed1984

The chemiluminescence of rabbit alveolar macrophages induced by quartz dust particles.

Quartz dust particles (respirable fraction) triggered luminol-dependent chemiluminescence (CL) when added to unstimulated rabbit alveolar macrophages (AM). It was shown by increasing the dust dose added to the same amount of cells, and conversely, that the intensity of chemiluminescent reaction depended on the ratio cells:dust particles. The ratio giving maximum CL yield was estimated.

Animals↗
PubMed1983

Plasma levels of oxytocin and vasopressin before, during and after parturition in cows.

In cows, plasma oxytocin and vasopressin were determined by specific and sensitive radioimmunoassays before, during and after parturition. In no case, oxytocin is elevated until the forelimbs of the foetus were distending the vagina and presenting at the vulva, supporting the view that endogenous maternal oxytocin does not primarily induce parturition. This finding is confirmed by simultaneous recording of myometrial electrical activity in 3 animals. Maximal oxytocin levels of 60.4 to 116 pg/ml plasma were measured at delivery of the foetus. The elevation in plasma vasopressin (peak values at delivery: 4.74 to 41.5 pg/ml) might be due, at least partially, to the increase in plasma osmolality during parturition.

Animals↗
PubMed1983

Thyroxine deiodination during in vitro lipid peroxidation of rat liver inner membrane particles.

Thyroxine inhibitory action was observed during in vitro Fe2+ induced lipid peroxidation of rat liver mitochondrial inner membrane particles. In the course of lipid peroxidation thyroxine was degraded preferentially to reverse triiodothyronine. Inhibition of lipid peroxidation by EDTA abolished the formation of reverse triiodothyronine. Nonenzymic deiodination of thyroxine leading to reverse triiodothyronine production may be of a considerable importance in various pathological states accompanied by lipid peroxidation.

Animals↗
PubMed1979

Simplified chromatographic separation of immunoglobulin M from G and its application to toxoplasma indirect immunofluorescence.

The indirect immunofluorescent (IIF) antibody technique for the detection of Toxoplasma gondii immunoglobulin M (IgM) often gives false negative results, probably due to the competition between IgG and IgM. We therefore adapted a gel filtration procedure for the separation of IgG and IgM to a routine diagnostic test capable handling at least 10 sera per day and requiring only 50 microliters of serum. The results from 108 sera having positive complement fixation titers for Toxoplasma showed that 17 were IgM positive when the whole serum was tested by IIF compared with 55 positive when the IgM fraction was used. Sera with antideoxyribonucleic acid titers do not give false positive results after fractionation, and the removal of IgG eliminates false positive results due to rheumatoid factor. A prospective study showed that Toxoplasma IgM may persist up to 9 months.

Antibodies↗
PubMed1979

Comparison of three methods of susceptibility testing of bacteroidaceae, peptococcaceae and other anaerobes to doxycycline.

The in vitro activity of doxycycline against 147 strains of gram-positive and gram-negative anaerobes was determined by broth dilution, agar dilution and agar diffusion tests. The strains were isolated from clinical specimens in 1977. Saccharolytic Bacteroides strains (39 B. fragilis, 6 B. thetaiotaomicron, 4 B. vulgatus) showed broth dilution MICs of less than or equal to 0.0625-4.0 microgram/ml after 5 h incubation and MICs of less than or equal to 16 microgram/ml after 15 h incubation at 37 degrees C. With strains of B. oralis, B. melaninogenicus ss. intermedius, B. corrodens, Veillonella sp. and Megasphaera elsdenii the broth dilution MICs were less than or equal to 0.0625-32 microgram/ml after 15 h incubation. Peptostreptococcus spp., Propionibacterium acnes, Eubacterium sp., Bifidobacterium sp. and Clostridium sp. had broth dilution MICs of less than or equal to 2 microgram/ml, whereas Peptococcus spp. were inhibited by less than or equal to 0.0625 to greater than 32 microgram/ml. With the great majority of strains tested, MICs were 2 to 256 times higher in agar than in broth dilution tests. Clinical and experimental studies seem to be needed to determine which of the in vitro data are correlated to the outcome of doxycycline therapy. Several groups and species were separately considered for statistical analysis of the relationship between zone size and MIC. With gram-positive anaerobes, correlation was poor between broth dilution MIC and zone size (correlation coefficients r = - 0.168 for Peptococcaceae, and r = - 0.108 for P. acnes). When calculating the regression lines for agar dilution MICs and zone diameters, a higher correlation was found (r = - 0.9 for Peptococcaceae; r = - 0.397 for P. acnes). With B. fragilis and other Bacteroides species correlation coefficients were r = - 0.807 to r = - 0.891 for broth and agar dilution MICs and zone size but stochastic linearity was lacking.

Anaerobiosis↗
PubMed1978

Structural analysis of viral replicative intermediates isolated from adenovirus type 2-infected HeLa cell nuclei.

Deoxyribonucleoprotein complexes released 17 h postinfection from adenovirus type 1 (Ad2)-infected HeLa cell nuclei were shown by electron microscopy to contain filaments much thicker (about 200 A [20 nm]) than double-stranded DNA (about 20 A [2 nm]). The complexes were partially purified through a linear sucrose gradient, concentrated, and further purified in a metrizamide gradient. The major protein present in the complexes was identified as the 72,000-dalton (72K), adenovirus-coded single-stranded DNA-binding protein (72K DBP). Three types of complexes have been visualized by electron microscopy. Some linear complexes were uniformly thick, and their length corresponded roughly to that of the adenovirus genome. Other linear genome-length complexes appeared to consist of a thick filament connected to a thinner filament with the diameter of double-stranded DNA. Forked complexes consisting of one thick filament connected to a genome-length, thinner double-stranded DNA filament were also visualized. Both thick and thin filaments were sensitive to DNase and not to RNase, but only the thick filaments were digested by the single-strand-specific Neurospora crassa nuclease, indicating that they correspond to a complex of 72K DBP and Ad2 single-stranded DNA. Experiments with anti-72K DBP immunoglobulins indicated that these nucleoprotein complexes, containing the 72K DBP, correspond to replicative intermediates. Both strands of the Ad2 genome were found associated to the 72K DBP. Altogether, our results establish the in vivo association of the 72K DBP with adenovirus single-stranded DNA, as previously suggested from in vitro studies, and support a strand displacement mechanism for Ad2 DNA replication, in which both strands can be displaced. In addition, our results indicate that, late in infection, histones are not bound to adenovirus DNA in the form of a nucleosomal chromatine-like structure.

Adenoviruses, Human↗
PubMed1977

Radioprotective effects of cyproterone acetate.

The pretreatment of irradiated mice by cyproterone acetate had a better radioprotective effect in comparison with orchidectomy, although the weight of the thymus was lower in the cyproterone acetate group. The radioprotective mechanisms involved in both cases were discussed.

Animals↗
PubMed1977

Enzymatic properties of viral replication complexes isolated from adenovirus type 2-infected HeLa cell nuclei.

When HeLa cell nuclei, isolated 17 h after infection with adenovirus type 2 (Ad2), were extracted with 200 mM ammonium sulfate, Ad2 nucleoprotein complexes were selectively released. These complexes contained a DNA polymerase activity that corresponded to DNA polymerase molecules actively engaged in Ad2 DNA replication. Under our high-salt (200 mM ammonium sulfate) incubation conditions, where no reinitiation occurred, full-length Ad2 DNA chains were synthesized by elongation of chains that had been initiated in vivo. This conclusion was further supported by density labeling experiments indicating that the in vitro DNA synthesis was semiconservative. Evidence is presented suggesting that at least part of the DNA polymerase molecules engaged in Ad2 DNA replication belong to the gamma class.

Adenoviridae↗
PubMed1977

Effect of intrauterine estriol on reproductive function in the rabbit.

The effect of intrauterine estriol on spontaneous ovulation, ovum fertilization, blastocyst development, and blastocyst implantation in rabbits has been investigated. Estriolreleasing intrauterine capsules constructed of biocompatible polymer were implanted in one uterine horn of adult New Zealand White female rabbits, while placebo-containing capsules were implanted into the contralateral horn. The animals were artificially inseminated and ovulated or mated to fertile bucks. The does were killed and their reproductive tracts were examined 54 hours, 6 days, and 10 days after ovulation-inducing injection or after coitus. The results indicate that intrauterine estriol released at a steady state rate of 1.25 mug/day effectively inhibits blastocyst development and implantation. This contraceptive effect was clearly local, since implantations in the contralateral,placebo-bearing horn were not inhibited. Furthermore, the same dose of estriol, when released systemically from a subcutaneously placed capsule, had no effect on implantation. Intrauterine estriol appeared also to have no effect on spontaneous ovulation or ovum fertilization.

Animals↗