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Biomedical subjects

D S Davis

Publications and source records attributed to D S Davis.

At least 73 records · Page 4Linked to original sources
PubMed1989

Serological prevalence and isolation of Babesia odocoilei among white-tailed deer (Odocoileus virginianus) in Texas and Oklahoma.

Serum samples collected from 581 white-tailed deer (Odocoileus virginianus) from Texas and from 124 white-tailed deer from Oklahoma were tested by the indirect fluorescent antibody technique against Babesia odocoilei. Prevalence of seropositive reactors varied from site to site in both states. Prevalence rates were statistically ranked as high, intermediate or low. Deer less than 12-mo-old had a significantly lower prevalence than all other age classes.

Age Factors↗
PubMed1989

Efficacy of triclabendazole against fascioloidiasis (Fascioloides magna) in naturally infected white-tailed deer (Odocoileus virginianus).

The efficacy of triclabendazole was evaluated in the treatment of naturally acquired Fascioloides magna infections in white-tailed deer (Odocoileus virginianus). Twenty white-tailed deer were captured on the Welder Wildlife Refuge (Sinton, San Patricio County, Texas, USA) and maintained in a 64 x 64 m deer enclosure. Ten deer were given a 5% suspension of triclabendazole orally at a dosage of 10 mg/kg body weight and 10 deer were given a placebo. Three wk later the deer were euthanized and examined for parasites. At necropsy 19 deer were infected. All specimens of F. magna from the tissues of the triclabendazole treated deer were dead or severely affected by the drug as indicated by changes in their size, color, movement and texture relative to those from control deer. The drug was considered 100% effective against this parasite. Adverse reactions of the deer to the drug were not observed.

Animals↗
PubMed1988

Immunolabeling of lipopolysaccharide liberated from antibiotic-treated Escherichia coli.

Increased anti-core glycolipid antibody binding was visualized by immunoelectron microscopy after incubation of Escherichia coli K1:O7 cells with a bacteriolytic antibiotic and compared with binding in control cells. The findings suggest that the core glycolipid regions of the lipopolysaccharides of some gram-negative bacilli can be effectively sequestered until liberated by antibiotic-induced cell lysis.

Anti-Bacterial Agents↗
PubMed1988

Interspecific transmission of Brucella abortus from experimentally infected coyotes (Canis latrans) to parturient cattle.

In four separate trials, 10 coyotes (Canis latrans) which had been individually fed mascerated bovine placental tissue experimentally inoculated with Brucella abortus strain 2308 were placed in a 1 ha isolation area with six parturient, non-B. abortus vaccinated, Brucella spp. seronegative Hereford heifers. During the second trial, three of the heifers became Brucella spp. seroreactive (as determined by the card, standard agglutination tube, rivanol, complement fixation, and enzyme labeled immunosorbent assay tests) 14 days after exposure to the B. abortus infected coyotes. Five of 10 coyotes in the second trial seroconverted to Brucella spp. positive by day 14 postexposure (PE) and by day 27 PE seven of the 10 coyotes were Brucella spp. reactive. The three Brucella spp. seroreactive heifers subsequently aborted on days 35, 64 and 66 PE and B. abortus strain 2308 was isolated from vaginal swabs, milk, and placental and fetal tissues. There was no serologic or bacteriologic evidence of transmission from B. abortus infected coyotes to the susceptible cattle recorded in the other three trials.

Animal Feed↗
PubMed1988

The Wistar Furth rat: an animal model of hereditary macrothrombocytopenia.

The mechanisms that determine and regulate platelet size are unknown. By phase microscopy, we observed that Wistar Furth (WF) rats had macrothrombocytopenia. In this study, we have characterized and compared platelets and megakaryocytes of WF rats with those of Wistar, Long-Evans hooded (LE), and Sprague-Dawley rats. In addition, we have examined the mode of inheritance of this WF rat platelet abnormality. The average platelet count of WF rats was only one-third that of the other three rat strains. In contrast, the mean platelet volume (MPV) of adult WF rats was twice that of the other rat strains; however, the average megakaryocyte diameter and DNA content distribution of WF rats were not significantly different from those of LE rats. The average megakaryocyte concentration was 30% lower in the WF strain compared with that of LE rats. Mazelike membrane formations were observed in WF platelets and megakaryocytes by electron microscopy. Reciprocal crosses of WF and LE rats resulted in offspring with MPVs and platelet counts like those of LE rats, indicating that the macrothrombocytopenic trait is recessive in its inheritance. Reciprocal marrow transplants between the WF and LE strains resulted in MPVs like those of the donor strain, demonstrating that the macrothrombocytopenia is an intrinsic marrow abnormality of the WF strain. Splenectomy did not alter the MPV of WF rats. The response of WF megakaryocytes and platelets to severe, acute thrombocytopenia was similar to that of LE rats except that the shift to higher megakaryocyte DNA contents was muted and platelet recovery was slower in the WF rats. In summary, the WF rat has a hereditary macrothrombocytopenia that is recessive in nature and not due to differences in megakaryocyte size or DNA content. These results suggest that the macrothrombocytopenia of WF rats results from the formation of fewer platelets per megakaryocyte, possibly resulting from a qualitative or quantitative defect in some component necessary for proper subdivision of megakaryocyte cytoplasm into platelets.

Age Factors↗
PubMed1987

Human epithelial cell expression of an Epstein-Barr virus receptor.

Cultured human epithelium bound and internalized radiolabelled Epstein-Barr virus (EBV) within 1 h of exposure. A similar percentage of cultured cells also were reactive with monoclonal antibodies to the EBV/C3d receptor of B lymphocytes. In cross-sections of fresh frozen, stratified epithelium, receptor expression seemed limited to the less differentiated subpopulation of cells. These findings support the notion of direct infection of epithelial cells by EBV and suggest a viral life cycle in epithelium dependent on the stage of cell differentiation.

Cell Line↗
PubMed1986

Development of murine monoclonal antibodies to Pneumocystis carinii.

Relatively little is known about the antigenic structure of Pneumocystis carinii and the immunopathogenesis of pneumonitis caused by P. carinii. To begin to define the antigenic character of the surface of this organism, we have produced murine monoclonal antibodies that react with the surface of P. carinii (obtained from rats), as detected by immunofluorescence and immunoelectron microscopy. Immunoblot analysis revealed that the six antibodies described in this report bound an antigen with an apparent molecular mass of 90,000-95,000 daltons. Although all six monoclonal antibodies bound P. carinii obtained from rats, only one (5E12) was also able to bind P. carinii obtained from rabbits, ferrets, and a human; this result demonstrated that isolates of P. carinii obtained from different species are not antigenically identical.

Animals↗
PubMed1984

Experimental infection of captive axis deer with Brucella abortus.

Four captive-raised axis deer, Axis axis (Erxleben), which were negative serologically to Brucella were inoculated with 1 X 10(8) virulent Brucella abortus biotype 1 organisms (Texas #221 isolate) administered bilaterally into the conjunctival sac. Sera collected from each deer prior to inoculation and 30 days post-inoculation (PI) were examined for Brucella antibodies by the buffered Brucella antigen (card), the rivanol precipitation, the standard tube agglutination, and the cold complement fixation tube serologic tests. All four axis deer converted serologically as determined by all tests at 30 days PI. Brucella abortus biotype 1 was isolated from 26 of 32 tissue samples collected at necropsy and also from milk from the lactating female.

Agglutination Tests↗
PubMed1981

Tobramycin in external eye disease: a double-masked study vs. gentamicin.

A double-masked randomized study was conducted at four centers to compare the efficacy and safety of tobramycin and gentamicin ophthalmic ointment in the treatment of superficial external eye disease. Seventy-seven patients with blepharitis and/or conjunctivitis were evaluated for safety, and 56 of the 77 individuals also qualified for evaluation of drug efficacy. After a 10 day treatment regimen, 97% of the tobramycin treated patients and 91.3% of the gentamicin treated patients were clinically cured or improved. Antibacterial effectiveness studies in the conjunctiva showed that tobramycin eradicated or controlled 87.8% of the bacterial infections vs. 77.4% for gentamicin. There was also a 9.3% adverse reaction rate with tobramycin vs. 17.6% with gentamicin. Primary symptoms consisted of erythema, injection, discomfort and itching. All adverse reactions were mild and cleared upon discontinuation of the study drug. While the trends seem to favor tobramycin, no difference was statistically significant at the p less than or equal to 0.05 level. These results indicate that tobramycin is a clinically effective and safe topical antibiotic and that it is comparable to gentamicin for topical treatment of bacterial external eye infections. It also may be better tolerated than gentamicin.

Anti-Bacterial Agents↗
PubMed1980

Referrals to psychiatric liaison nurses: changes in characteristics over a limited time period.

This article reviews the literature on the consultant/consultee relationship within psychiatric liaison nursing. Data on 284 referrals from staff nurses to psychiatric liaison nurses (PLNs) in a teaching hospital are examined to discover whether the nature of the referrals changes with the evolving consultation relationship. Referrals are found to change over time in their specificity, focus, level of sophistication, and kind of PLN involvement requested. Possible explanations for these changes are discussed.

Hospitals, Teaching↗
PubMed1980

An experimental infection of Trypanosoma cruzi in striped skunks (Mephitis mephitis).

Four adult (3 male, 1 female) captive-raised, decented, striped skunks (Mephritis mephitis) were infected experimentaly with a field strain (Texas-Tulane) of Trypanosoma cruzi, originally isolated from a naturally-infected dog. Two skunks were injected intravenously with approximately 4.5 x 10(6) viable T. cruzi trypomastigotes. Two skunks were inoculated per os and per conjunctivum with 10 ml of phosphate buffered saline containing macerated, T. cruzi-infected triatomine intestines and intestinal contents. The skunks had minimal clinical manifestations with no mortalities occurring during 46 days post-exposure. Sera from all skunks were positive at 24 days post-inoculation (PI) by the direct and latex agglutination tests. Blood cultures from the 4 skunksd were positive for T. cruzi at day 24 PI and 3 were positive at day 46 PI. All skunks had mild to moderately severe chronic granulomatous myocarditis of the atria and ventricles. Typical T. cruzi amastigotes were present within myocardial fibers in 3 of 4 skunks.

Animals↗
PubMed1979

Brucella abortus in coyotes. I. A serologic and bacteriologic survey in eastern Texas.

Prevalence of Brucella abortus serum antibodies in coyotes from east central Texas was determined by the buffered Brucella antigen (card test), rivanol, standard agglutination tube, and cold complement fixation tube tests. Eighteen percent (9 of 51) of the coyotes were positive serologically. B. abortus biotype 1 was isolated from various tissues from 7 of 43 coyotes by bacteriologic culture. Congenital transmission was found.

Animals↗
PubMed1978

Naturally occurring hepatozoonosis in a coyote.

Schizonts of Hepatozoon sp. were found in the myocardium of an adult cyote (Canis latrans) collected from the Aransas National Wildlife Refuge, Austwell, Texas. This constitutes the first time hepatozoonosis has been recorded in Canidae in the Western Hemisphere.

Animals↗