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Biomedical subjects

W R Davidson

Publications and source records attributed to W R Davidson.

At least 73 records · Page 4Linked to original sources
PubMed1988

Serological monitoring of eastern wild turkeys for antibodies to Mycoplasma spp. and avian influenza viruses.

From 1981 through 1986, plasma or serum samples were obtained from 322 wild turkeys (Meleagris gallopavo) from Georgia (n = 111), Kentucky (n = 21), Louisiana (n = 22), North Carolina (n = 118), Tennessee (n = 19), Missouri (n = 24) and Iowa (n = 7). These samples were tested for antibodies to Mycoplasma gallisepticum (MG) and in most instances, M. synoviae (MS), M. meleagridis (MM), and avian influenza (AI) virus. All 322 turkeys were seronegative for MG by the rapid plate agglutination (RPA) test. All of a subsample (n = 147) also were negative (titer less than or equal to 1:40) for MG by the hemagglutination inhibition (HI) test. Five of 253 turkeys (2%) were seropositive (+4 reaction) for MS by the RPA test; however, HI tests for MS on these five turkeys were negative as were attempts to isolate MS from trachea and homogenized lung tissue. Three of 253 turkeys (1%) were seropositive (+1 to +3 reactions) for MM by the RPA test. None of 210 turkeys had antibodies to AI by the agar gel precipitation test. These data suggest that populations of native eastern wild turkeys are not important in the epizootiology of MG, MS, MM, or AI.

Animals↗
PubMed1988

Prevalence and identity of coccidia in pen-raised wild turkeys.

One hundred nineteen pen-raised wild turkeys (Meleagris gallopavo) from 12 locations in nine states in the United States were examined for coccidia by sugar flotation of intestinal contents and mucosa or by subinoculating the contents into uninfected domestic turkeys. Seventy-eight (66%) of the turkeys were positive for coccidia. There were no differences in the frequency of coccidia among adult, sub-adult or juvenile turkeys. More females (75%) were infected than males (48%). The species of coccidia from 30 of the turkeys were identified based on microscopic examination of oocysts, fresh scrapings, stained sections and inoculations of bobwhites (Colinus virginianus). The frequency of each species was Eimeria meleagrimitis (97%), E. gallopavonis (47%), E. meleagridis (27%), E. dispersa (17%), E. innocua-E. subrotunda (13%), E. adenoeides (7%) and an undescribed species (3%). Of the 30 turkeys in which the species of coccidia was determined, 30% had a single species infection, 40% had two species, 20% had three species and 10% had four species.

Animals↗
PubMed1988

Distribution of Spiculopteragia pursglovei and S. odocoilei (Nematoda: Trichostrongyloidea) from white-tailed deer (Odocoileus virginianus) in the southeastern United States.

The distribution of Spiculopteragia pursglovei (= Apteragia pursglovei) and S. odocoilei (= A. odocoilei) in 12 southeastern states was determined after examining the abomasal contents of 1,369 white-tailed deer over an 8-yr period. Spiculopteragia odocoilei was encountered with much greater frequency than S. pursglovei except in some areas along the Mississippi River drainage and the coasts of North Carolina and South Carolina. In instances where both parasites were found in a population, one usually expressed a dominance in both prevalence and intensity. These findings are in agreement with those of an earlier study conducted in the southeastern United States.

Abomasum↗
PubMed1987

Preserved cardiac beta-adrenergic sensitivity in early renovascular hypertension.

To determine the mechanism of blunted sympathetic reflex responses in early renovascular hypertension, we measured inotropic and chronotropic responses of the heart to beta-adrenergic stimulation in vivo and myocardial beta-adrenergic receptor number and adenylate cyclase activity in 10 dogs during an early stage of one-kidney renal hypertension. Mean aortic pressure was higher in the hypertensive dogs (152 +/- 4 mm Hg) than in eight sham-operated dogs (122 +/- 1 mm Hg; p less than 0.001), but heart rate, cardiac output, and left atrial pressure did not differ between the two groups. Blood pressure reduction with a direct-acting vasodilator, pinacidil, resulted in marked increases in heart rate (+97 +/- 12 beats/min) and rate of change of left ventricular pressure (dP/dt; +1447 +/- 367 mm Hg/sec) in normotensive dogs but only blunted heart rate (+54 +/- 12 beats/min) and minimal left ventricular dP/dt (+376 +/- 264 mm Hg/sec) responses in hypertensive dogs. In contrast, intravenously administered isoproterenol produced similar increases in heart rate and left ventricular dP/dt in the two groups. These two groups also did not differ in either left ventricular beta-adrenergic receptor number and affinity or basal, isoproterenol-stimulated, and fluoride-stimulated adenylate cyclase activity. Thus, despite blunted reflex responses to blood pressure reduction, hypertensive dogs showed neither reduction in chronotropic and inotropic responses to direct beta-adrenergic stimulation nor beta-adrenergic desensitization of the myocardium, as assessed by beta-adrenergic receptor number and adenylate cyclase activity. Blunted reflex responses in this model of early hypertension must be due to factors operating at some locus other than the beta-adrenergic receptor-adenylate cyclase complex.

Adenylyl Cyclases↗
PubMed1987

Parasites, diseases and health status of sympatric populations of sambar deer and white-tailed deer in Florida.

From December 1983 to December 1984 a study on parasites, diseases and health status was conducted on sympatric populations of sambar deer (Cervus unicolor) and white-tailed deer (Odocoileus virginianus) from St. Vincent Island, Franklin County, Florida. Ten sambar and six white-tailed deer were examined. White-tailed deer had antibodies to epizootic hemorrhagic disease virus and bluetongue virus. Serologic tests for antibodies to the etiologic agents of bovine virus diarrhea, infectious bovine rhinotracheitis, vesicular stomatitis, parainfluenza 3, brucellosis, and leptospirosis were negative in both species of deer. White-tailed deer harbored 19 species of parasites; all were typical of the parasite fauna of this species in coastal regions of the southeastern United States. Sambar deer harbored 13 species of parasites, which apparently were derived largely from white-tailed deer. The only exception was Dermacentor variabilis which occurs frequently on wild swine on the island. The general health status of sambar deer appeared to be better than that of white-tailed deer. This was hypothesized to result from the sambar deer's utilization of food resources unavailable or unacceptable to white-tailed deer and to the absence and/or lower frequency of certain pathogens in sambar deer.

Animals↗
PubMed1986

Dobutamine-induced cardiac adaptations: comparison with exercise-trained and sedentary rats.

To investigate dobutamine-induced cardiac adaptations, we compared dobutamine-treated with swim-trained and sedentary control rats. After 14 wk of treatment, heart rate was lower in the dobutamine-treated (279 +/- 6) and exercise-trained (287 +/- 4 beats/min) groups than in the control animals (305 +/- 3 beats/min; P less than 0.05). The exercised rats gained less weight (164 +/- 11 g; P less than 0.05) than the dobutamine-treated (238 +/- 16 g) and the control animals (231 +/- 12 g). Also, compared with the two other groups, the exercise group had higher relative heart weights (3.47 +/- 0.08 vs. 2.82 +/- 0.06 and 2.90 +/- 0.05 g/kg in the dobutamine and control groups, respectively; P less than 0.05) and lower epididymal fat pad weights (6.6 +/- 0.4 vs. 13.3 +/- 1.0 and 11.4 +/- 0.5 g/kg in the dobutamine and control groups, respectively; P less than 0.05). However, both the maximum heart rate produced by isoproterenol and the isoproterenol dose producing 50% of the peak heart rate response were similar among the three groups. Myocardial norepinephrine content, beta-adrenergic receptor number, and adenylate cyclase activation by isoproterenol, NaF, 5'-guanylyl imidodiphosphate, and forskolin also did not differ. Thus, although there were differences between the dobutamine-treated and the exercised rats, the two groups were similar in that they developed bradycardia that was not due to cardiac adrenergic desensitization.

Adaptation, Physiological↗
PubMed1985

Breath analysis by API/MS--human exposure to volatile organic solvents.

The expired breath of subjects, exposed for periods of ca. 90 min to atmospheres artificially contaminated with low levels of methanol, (ca. 100 ppm) toluene (ca. 50 ppm) or tetrachloroethylene, (ca. 50 ppm) was monitored during and after the exposure period using an atmospheric pressure ionization mass spectrometer, fitted with a direct breath analysis system. The retention of solvent by the subjects, estimated from steady state levels in the expired breath, averaged 82% of the inspired level for methanol, 83% for toluene and 87% for tetrachloroethylene. The elimination of unchanged solvent via respiration during the post exposure period followed first order kinetics with mean half life values of 24 min for methanol, 27 min for toluene and 79 min for tetrachloroethylene.

Atmospheric Pressure↗
PubMed1985

Parasites, diseases, and health status of sympatric populations of fallow deer and white-tailed deer in Kentucky.

In August 1983, a study on parasites, diseases, and health status was conducted on sympatric populations of fallow deer (Dama dama) and white-tailed deer (Odocoileus virginianus) from Land Between The Lakes, Lyon and Trigg counties, Kentucky. Five adult deer of each species were studied. White-tailed deer had antibodies to epizootic hemorrhagic disease (EHD) virus and Leptospira interogans serovariety icterohemorrhagiae, and fallow deer had antibodies to bluetongue and EHD viruses. Serologic tests for bovine virus diarrhea virus, infectious bovine rhinotracheitis virus, parainfluenza3 virus, and Brucella spp. were negative. One white-tailed deer had an infectious cutaneous fibroma, and one fallow deer had pulmonary mucormycosis. White-tailed deer harbored 16 species of parasites, all of which are considered typical of the parasite fauna of this host in the southeastern United States. Fallow deer harbored nine species of parasites, including eight species known to occur in white-tailed deer on the area and one species (Spiculopteragia assymmetrica) that is not. All fallow deer had inflammatory lesions in the spinal cord and/or brain that were attributed to prior infection with meningeal worm (Parelaphostrongylus tenuis), indicating that P. tenuis infections are not always fatal for this species. The apparent high rate of exposure of Land Between The Lakes fallow deer to P. tenuis without a resultant high rate of clinical cerebrospinal parelaphostrongylosis is hypothesized to be due to a low prevalence and intensity of P. tenuis, partial innate resistance of fallow deer, and acquired immunity.

Animals↗
PubMed1985

Diseases diagnosed in wild turkeys (Meleagris gallopavo) of the southeastern United States.

Diagnostic findings are presented on 139 sick or dead wild turkeys examined during the period 1972 through 1984. Turkeys originated from eight southeastern states (Alabama, Arkansas, Florida, Georgia, South Carolina, Tennessee, Virginia, West Virginia) and included 31 turkeys categorized as capture-related mortalities and 108 turkeys categorized as natural mortalities. Frequent diagnoses (greater than or equal to 10% of case accessions) in the natural mortality group were trauma, avian pox, and histomoniasis. Less frequent diagnoses (less than or equal to 4% of case accessions) included malnutrition/environmental stress syndrome, coligranuloma-like condition, crop impaction, bumblefoot, organophosphate toxicosis, infectious sinusitis, a lympho-proliferative disease, salmonellosis, aspergillosis, toxoplasmosis, crop trichomoniasis, and melorheostosis.

Animals↗
PubMed1983

Parasites, diseases, and health status of sympatric populations of sika deer and white-tailed deer in Maryland and Virginia.

In July 1981, investigations on parasites, diseases, and herd health status were conducted on sympatric populations of sika deer (Cervus nippon) and white-tailed deer (Odocoileus virginianus) from Blackwater National Wildlife Refuge (Maryland) and Chincoteague National Wildlife Refuge (Virginia) on the Delmarva Peninsula. Five adult deer of each species were collected from each location and subjected to thorough necropsy examinations and laboratory tests. White-tailed deer at both locations harbored protozoan, helminth, and arthropod parasites typically associated with this species throughout the southeastern United States. In contrast, sika deer at both locations harbored only light burdens of ticks, chiggers, and sarcocysts. Serologic tests for antibodies to seven infectious disease agents revealed evidence of exposure to bovine virus diarrhea (BVD) virus, infectious bovine rhinotracheitis virus, and parainfluenza3 virus in white-tailed deer, but only BVD virus in sika deer. At both locations the general health status of sika deer was superior to that of white-tailed deer.

Animals↗
PubMed1982

Parasitisms among wild swine in southeastern United States.

Examination of 187 wild swine from 20 locations in 11 southeastern states revealed at least 25 species of endoparasites and 7 species of ectoparasites. Three parasites of public health importance (Sarcoptes scabiei, Spirometra sp, and Toxoplasma gondii) were disclosed by this study. The absence of Trichinella spiralis indicates that wild swine in the Southeast are not a reservoir for Tr spiralis.

Animals↗
PubMed1981

Helminth parasites of translocated raccoons (Procyon lotor) in the southeastern United States.

Raccoons (Procyon lotor) typical of animals released by private hunting clubs in the Appalachian Mountains were examined for helminth parasites to evaluate the influence raccoon translocation might have on parasitic diseases. Results were compared with data from resident raccoons from characteristic release areas. Translocated raccoons harbored 19 helminth species that were exotic to resident animals. Most of these exotic parasites were trematodes (74%). An additional 19 species were found in both translocated and resident raccoons, and another 5 species were present only in residents. Three of the 19 exotic helminth parasites and 10 of the 19 enzootic species found in translocated raccoons are known to have some degree of pathogenicity to raccoons, other wildlife, domestic animals or man. At present, disease risks associated with the helminth parasites of these translocated raccoons were not considered alarmingly high; however, potential problems that could not be discounted were artificial intensification of undesirable enzootic parasites on release sites or expression of pathogenicity by exotic parasites presently considered nonsignificant.

Animals↗
PubMed1981

Studies on cross-transmission and pathogenicity of Haemonchus contortus in white-tailed deer, domestic cattle and sheep.

Experiments were conducted to compare the relative pathogenicity and infectivity of deer- and cattle-derived Haemonchus contortus for three hosts, viz., white-tailed deer, cattle and domestic sheep. Parameters evaluated for all animals were: general physical condition, basic hematologic values, fecal egg counts and parasite infectivity rates. Clinical signs attributable to H. contortus infections were not observed in any of the experimental animals. Deer harboring H. contortus burdens greater than 70 worms/kg body weight had decreased packed cell volume, hemoglobin and total serum protein values. Statistical analyses indicated there was not a significant difference (P greater than .05) in infectivity of deer-derived H. contortus in these hosts. No significant difference (P greater than .05) in infectivity for deer was noted between deer-derived H. contortus and cattle-derived H. contortus. Morphometric comparisons of helminths recovered indicated that parasites of deer and cattle origin were both compatible with the description for H. contortus. Results suggest that cross-transmission of H. contortus occurs between deer and domestic livestock.

Animals↗
PubMed1981

Endoparasites and selected infectious agents in bobcats (Felis rufus) from West Virginia and Georgia.

A total of 143 bobcats (Felis rufus) from West Virginia and 10 bobcats from Georgia was examined for parasites and selected infectious agents. A total of 31 species of parasites was recovered including 1 protozoan, 1 trematode, 4 cestodes, 1 acanthocephalan and 24 nematodes. Results indicate bobcats are important definitive hosts for Sarcocystis sp. and Toxoplasma gondii. Thirteen species (Paragonimus kellicotti, Spirometra mansonoides, Taenia macrocystis, T. rileyi, Capillaria putorii, Toxascaris leonina, Toxocara mystax, Ancylostoma braziliense, A. tubaeforme, Oslerus rostratus, Molineus barbatus, Physaloptera rara, and Troglostrongylus wilsoni) were considered common components of the helminth fauna of southeastern bobcats. Host age and/or host density had significant relationships (P less than or equal to 0.05) to the prevalences of infection of some parasites. Salmonella spp. were isolated from six bobcats, and Yersinia enterocolitica was isolated from a single bobcat. Bobcat populations studied did not have overt clinical parasitism or disease during the fall and winter.

Animals↗
PubMed1980

A computerized chart management system for medical records.

A computerized system is described which improves turnaround time for completion of in-patient medical records and copes with the problem of delinquent records. Many patients seen at University Hospital are referred from throughout the State, thus the specialist must stay in contact with the referring physician for optimal patient care. The Medical Records Department assists in this effort through use of the system, which includes pertinent dates and other information concerning each patient. Several reports are generated from this information, e.g., outstanding records sorted by department/physician and outstanding records with charges pending. The total software system is comprised of 22 program, 2 sub-routines, and 4 data files; the total disk storage space required is 1413 kilobytes.

Computers↗