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Biomedical subjects

A Olsen

Publications and source records attributed to A Olsen.

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

Pharmacokinetics of metronidazole and its major metabolite after a high intravenous dose.

The pharmacokinetics of metronidazole (M) and hydroxy-metronidazole (OH-M) were determined in 8 healthy volunteers after a single dose of 1.5 g metronidazole given as an intravenous infusion during 50 min. High-pressure liquid chromatography was used for the assays. The serum concentration determined 1 h after the start of infusion was 40.21 +/- 6.54 mg/1. The peak concentrations of the metabolite were observed after 8-12 h. The serum concentrations of M and OH-M were detectable throughout the 48 h monitored. The serum half-life of M was 7.6 h and of OH-M 13.3 h. The terminal phase distribution volume was 43.2 lit and the total body clearance 4.0 lit./h. The prophylactic use of 1.5 g of metronidazole given as a single intravenous dose 1 h prior to surgery is supported by the pharmacokinetic assessments in this study.

Drug Evaluation↗
PubMed1981

Argyria-tissue deposition of silver as selenide.

Generalized argyria was precipitated in a patient by treating gingival erosions with a solution of silver nitrate for several months. High silver concentrations were measured in skin biopsies. treatment with penicillamine did not increase the urinary silver excretion, indicating that silver is deposited in tissues in a chemically stable and apparently inert form. Electron microscopy showed that in the kidney, silver was deposited mainly in the basal membranes as electron-dense particles. These particles were studied by using X-ray emission spectrometry and electron diffraction. the particles consisted of Ag2Se in the low temperature orthorhombic alfaform. The lattice parameters are: a = 0.433 nm, b = 0.693 nm and c = 0.784 nm. This selenide complex seems to be remarkably non-toxic, since the renal function of the patient was unaffected and only negligible reactive changes were observed in kidney biopsies.

Argyria↗
PubMed1981

Testicular cyclic nucleotide phosphodiesterase in the rat. Kinetic properties and changes with age.

The assay for cyclic nucleotide phosphodiesterase has been applied, with certain modifications, to the measurement of the soluble forms of these enzymes in the rat testis. The homogenization and incubation conditions were adjusted to achieve linear product formation as a function of time and protein concentrations and the resulting products were isolated by ion exchange chromatography using 5 mM HCl as the eluting agent. Phosphodiesterase activities were present in the testicular cytosol (105,000 g supernatant) of adult rats which were capable of hydrolyzing cAMP with a high (Km2 microM) and low Km20 microM) affinity and GMP with a relatively high affinity (Km3 microM). The low affinity cAMP enzyme activity could be stimulated with divalent ions such as calcium, magnesium, and manganese. At 18 days of age, all three enzyme activities were present in the testis, although both the high and low affinity cAMP phosphodiesterase displayed maximal rates (Vmax) that were only one third of the adult testis (when expressed per mg protein).

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1979

Activation of reticuloendothelial cells following infection with murine cytomegalovirus.

Macrophage and reticuloendothelial system function was investigated in adult, female C3H mice during the course of a nonlethal infection with murine cytomegalovirus (MCMV). Peritoneal macrophages harvested from mice infected three to 21 days previously were tumoricidal in vitro for a syngeneic mammary tumor cell line and showed antiviral activity by suppressing replication of vaccinia virus in a fibroblast monolayer. In addition, macrophages harvested from animals on days 7 and 14 after MCMV infection manifested augmented phagocytosis of yeast particles in vitro. Furthermore, enhanced levels of chemiluminescence were emitted during phagocytosis of zymosan particles by macrophages harvested on days 3 and 7 after MCMV infection. Finally, enhanced protection against Listeria monocytogenes was demonstrated in mice on days 7, 14, and 21 after MCMV infection. These findings support the concept of activation of the reticuloendothelial system during viral infection.

Animals↗
PubMed1979

Prolactin and Leydig cell responsiveness to LH/hCG in the rat.

The effects of prolactin and 2-bromo-alpha-ergocryptine (CB-154) on Leydig cell function in intact and hypophysectomized male rats were studied. The conclusions can be summarized as follows: prolactin (1) has a direct stimulatory effect on the number of LH receptors on rat Leydig cells, (2) has no effect on the characteristics of the dose-response curve of isolated Leydig cells (hCG stimulated androgen production) in vitro even after treatment with pharmacological doses in vivo, and (3) acts synergistically with LH to stimulate the quantity of androgen produced by the Leydig cells in response to hCG in vitro and to increase the sensitivity of the hCG-dose-response curve. Treatment of intact rats with CB-154 reduced the quantity of androgen produced by the Leydig cells in vitro after exposure to hCG and decreased LH binding to the same cells by 50%. These results suggest that under normal conditions, endogenous prolactin plays a key role in maintaining the functional integrity of rat Leydig cells.

Animals↗
PubMed1979

A summary of the prevalence of Parelaphostrongylus tenuis in a captive wapiti population.

A total of 87 brains from harvested and collected wapiti and red deer (Cervus spp.) were examined grossly and microscopically between 1973 and 1977 in a 2104 ha. preserve. Prevalence of infection significantly increased from 26.6% of the sample in 1973 to 64.3% in 1975 (P less than .05). A decline to 47.7% in 1977 (P greater than .05) was not significant. However, the number of clinical cases was significantly higher in 1976-1977 (P less than .02) than previously reported in 1973-1975.

Animals↗
PubMed1978

Topochemistry of trace metals in nasal mucosa. Potentialities of some histochemical methods and energy dispersive X-ray microanalysis.

Histochemical methods and energy dispersive X-ray micro-analysis (EDX-analysis) were evaluated in model experiments and on tissue sections for their usefulness in detecting traces of metals in biological tissue. The goal for this study was to establish a method for localization of nickel deposits in the nasal mucosa, where it has been found in concentrations between 1 and 40 microgram/g in nickel exposed individuals. The histochemical methods tested were staining with dimethylglyoxime, rubeanic acid and dithizone, the Turnbull and Prussian blue methods and TIMM'S sulphide silver procedure. In model experiments nickel-, cobalt-, copper-, zinc- and ironsalts were applied to thin-layer chromatography sheets (TLC-sheets) and stained by the histochemical methods. Spots containing 500 and 50 ng of these metals represented the smallest amounts that could consistently be detected in these experiments, except for the sulphide silver method which seemed a little more sensitive. With the latter method, moreover, zinc was detected in 40 micrometer thick cryostat sections of gelatine made up with 1 microgram/g of the metal. For nickel the corresponding figure was 10 to 50 microgram/g. On specimens of nasal mucosa from nickel-exposed workers, a faint colour was obtained in 40 micron thick cryostat sections from specimens that had been immersed in dithizone, but the colour was too weak for histological analysis. None of the other coloured chelating agents caused noticeable staining when applied to blocks or to cryostat sections. TIMM'S sulphide silver method caused strong staining of the basal layers of the surface epithelium and of fibroblast-like cells in the underlying connective tissue. This staining pattern is described in more detail in a separate report. Rat liver tissue was analyzed by atomic absorption before and after araldite embedding. Blocks of gelatine made up with nickel, copper, zinc and iron were embedded in epoxy resin and analyzed by atomic absorption. Large changes in the metal concentrations, usually an increase, were found after embedding. Ultrathin sections from this material were used to test the sensitivity of the EDX-equipment. Referring to the concentrations determined by atomic absorption in the embedded material, iron was detected at 1215 microgram/g and 362 microgram/g (gelatine standards) but not at 167 microgram/g (rat liver). Similar values could not be determined for nickel, copper or zinc, because of background radiation resulting from the presence of these metals in the instrument. We did not succeed in establishing a procedure for detecting nickel deposits in nasal mucosa with any of the methods which were tested. The most sensitive but least specific of the tested methods for visualizing heavy metals in the nasal mucosa, was TIMM'S sulphide silver procedure. The preparation of tissue for this method is discussed.

Animals↗
PubMed1978

The development of clinical signs and the population significance of neurologic disease in a captive wapiti herd.

Clinical signs attributable to meningeal worm (Parelaphostrongylus tenuis) were recorded in three male and three female wapiti (Cervus elaphus canadensis) ranging in age from 5 - 29 months. The study was conducted from September, 1976 to May, 1977 in a 2104-ha preserve. Some differences were noted in occurrence, time schedule and sequence of signs but the basic pattern was similar. The mean time between initial sign observed and death was 100 days. The effect of neurologic disease on population socialization, harvest and recruitment is discussed. A comparison of projected potential population numbers with sighting data in 1959-1977 revealed a trend of lower than expected numbers since 1968 related to suspected neo-natal mortality as well as known natural mortality in the younger age classes due to meningeal worm infection.

Animals↗