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Biomedical subjects

G R Hogan

Publications and source records attributed to G R Hogan.

At least 19 recordsLinked to original sources
PubMed2000

Comparative erythropoietic effects of three vanadium compounds.

The biotoxic effects of vanadium are variable depending upon a number of factors including the oxidation state of the test compound. This study reports the effects of three vanadium compounds on peripheral erythrocytes. On day 0 female ICR mice received a single injection of vanadium chloride (V-III), vanadyl sulfate (V-IV), or sodium orthovandate (V-V). At scheduled intervals post-injection, the number of circulating erythrocytes [red blood cells per millimeter cubed (RBC/mm3)], reticulocyte percentages, and radioiron uptake percentages were determined and compared to mice receiving saline only. Data show that all three test substances promoted a significant lowering of RBC/mm3 beginning on day 1 for V-IV and V-V and on day 2 for V-III through day 4. The reticulocyte percentages increase followed the same time course as that of the peripheral RBC decrease. Peak reticulocytosis was noted on days 2 and 4 for all three vanadium-treated groups; for V-IV and V-V the increase continued to day 6. Radioiron data showed an erythropoietic stimulation by a significant increase in uptake percentages on days 4-6 after vanadium injections compared to saline-treated controls.

Animals↗
PubMed1998

Selenate- and selenomethionine-induced leukopenia in ICR female mice.

The investigations reported here were conducted to gain a better understanding of the comparative toxicity of selenium. Sodium selenate and selenomethionine were administered to young adult ICR female mice. Peripheral leukocyte counts and ratios of agranulocyte (Ag) to granulocyte (G) leukocytes were determined from blood that was collected at regularly scheduled intervals. Data indicated that both forms of selenium induced a transient yet marked decrease in the number of circulating leukocytes (leukopenia) following serial injections (2 mg Se/kg/injection). The leukopenia was more extensive and of a greater duration for selenomethionine-treated mice. For selenate-injected animals the Ag/G ratio increased sharply while the ratio shift for selenomethionine-injected mice was significantly less. Data are interpreted in regard to the different possible modes of action of selenate and selenomethionine on peripheral leukocytes causing leukopenia and the variable Ag/G ratio values.

Animals↗
PubMed1995

Incubation temperature as a modifying factor on survival of Tenebrio molitor reared in selenium-containing media.

Newly emerged Tenebrio molitor were reared at 4, 25, and 37 degrees C in nutrient media supplemented with sodium selenate (0.0125, 0.0200, 0.0500, and 0.1000%). Ten insects comprised each group. Controls were maintained in unsupplemented medium at the same temperatures as the experimental groups. Survival percentages were determined. Survival curves were estimated at given times postincubation. Controls at 4 and 37 degrees C showed an increased lethality compared to those insects at 25 degrees C. Data indicate that 4 degrees C had a protective effect on survival for insects reared in media containing the three highest concentrations of selenium. For insects at 37 degrees C, killing was striking and equivalent for all groups, irrespective of media supplementation.

Animals↗
PubMed1992

Cadmium treatment and lead-induced suppression of splenic erythropoiesis.

Young adult female mice were injected with lead acetate (d 0). Following injection, determinations were made of the percentages of radioactive iron (59Fe) uptake into the hemoglobin of erythrocytes produced by spleen. Control 59Fe uptake percentage vacillated between 4.2 and 5.5 within the 7-d period of observation. On d 4 following lead treatment, splenic percentages were dramatically reduced below those of the saline-injected controls; by d 6 the splenic 59Fe uptake of lead-treated mice was comparable to that of controls. For rodents injected with cadmium chloride on 0, the 59Fe uptake values showed a statistically significant elevation by d 2, which was extended beyond that of the controls' d 4 value. For those animals receiving both lead and cadmium (d 0), the uptake percentages paralleled those of the controls throughout the 7-d period of observation. These data suggest that the inhibitory effect of lead on erythropoiesis of the spleen is blocked by a concurrent cadmium treatment. Results are interpreted in regard to a possible vulnerable target and competition for the target by lead and cadmium.

Animals↗
PubMed1991

Cephalic replacement in severe shoulder dystocia.

In cases of severe shoulder dystocia, the outcome may be improved if cephalic replacement is attempted earlier. Severe shoulder dystocia is usually unresponsive to the traditional measures. Although still controversial, this maneuver may prove to be life-saving in an undeliverable fetus.

Adult↗
PubMed1990

Peripheral erythrocyte levels, hemolysis and three vanadium compounds.

Three vanadium compounds of different valence states were administered to adult mice. Two, four, and eight days following treatment of vanadium, cardiac blood was collected. The blood sample was used to ascertain the peripheral erythrocyte count (cell/mm3) and to determine the in vitro hemolytic index of erythrocytes obtained from mice treated in vivo with either the tri-, tetra-, or pentavalent vanadium compound. Data indicate that the tetravalent form was the most effective test substance in 1) promoting rupture of isolated erythrocytes compared to red cells retrieved from control mice and 2) depressing the erythrocyte count obtained from heart blood; maximum effects were manifest four days post-treatment. For all treatments there appeared to be a good correlation between the degree of vanadium-induced hemolysis and the peripheral erythrocyte count reduction following exposure to the vanadium.

Analysis of Variance↗
PubMed1989

Concurrence of limb girdle muscular dystrophy and myasthenia gravis.

We describe a case of limb girdle muscular dystrophy with associated myasthenia gravis. This association has not been previously noted in the literature. The unusual feature of the case was that symptoms coexisted for several years before a correct diagnosis was made. The diagnosis was based on the clinical picture and the results of the muscle biopsy and electrophysiologic testing. This case serves to illustrate the fact that a separate problem should be considered when the clinical picture is not compatible with the underlying diagnosis.

Biopsy↗
PubMed1985

Neutrophilic granulocytosis following lead acetate in female mice.

Lead induces an abrupt neutrophilic granulocytosis with the peak response detected 4 days after treatment. Using the incorporation of tritiated thymidine as an index of neutrophil production, autoradiographic analysis revealed that only about 16% of the total neutrophil increase is associated with a stimulatory effect on production. The remainder of the increase appears to be linked to the panhistotoxic action of lead, promoting migration of neutrophils from reserve sites in the wake of tissue damage.

Animals↗
PubMed1985

Modified methods for preparation of cryostat sections of skeletal muscle.

We developed two modified methods for the preparation of cryostat sections of skeletal muscle: one using solid carbon dioxide and the other using the ultra-low freezer to prepare 2-methylbutane (isopentane) for freezing of skeletal muscle. The results were quite satisfactory, with good preservation of cellular details and histochemical properties. Freezing artifacts were minimal when compared with the standard liquid nitrogen method.

Adenosine Triphosphatases↗