Biomedical subjects

L A Elliott

Publications and source records attributed to L A Elliott.

5 recordsLinked to original sources

PubMed1992

Distribution of the Lyme disease vector, Ixodes dammini (Acari: Ixodidae) and isolation of Borrelia burgdorferi in Ontario, Canada.

Ixodes dammini Spielman, Clifford, Piesman & Corwin was confirmed at Long Point, Lake Erie, Ontario, on small mammals and white-tailed deer and by dragging for ticks. Mean intensities of up to 16.2 larvae and 2.1 nymphs were found on Peromyscus leucopus (Rafinesque), with an overall prevalence of infestation up to 92%. Adult I. dammini (101.6 +/- 77.63) (mean +/- SD) were found on 8 white-tailed deer, Odocoileus virginianus (Zimmerman). The seasonal pattern of recovery of ticks from hosts and the environment resembled that described elsewhere. I. dammini was not found on 952 small mammals trapped at 25 other localities throughout Ontario, although other ticks (Derma-centor variabilis (Packard), Ixodes angustus Neumann, I. marxi Banks, I. muris Bishopp & Smith) were encountered sporadically. I. dammini is not widespread or common in Ontario other than at Long Point. Borrelia burgdorferi was isolated from 10 of 151 P. leucopus; from larval and nymphal I. dammini; and from nymphal and adult D. variabilis, all from Long Point. B. burgdorferi was not recovered from 116 small mammals from localities other than Long Point. Seropositive P. leucopus (indirect fluorescent antibody test titer > or = 1:20) were common (up to 30% prevalence in July 1988, n = 23) on Long Point. Where I. dammini was not found, the prevalence of seroreactors among Peromyscus was 0 (15 sites), < 12% (5 sites), and 29% (1 site); seroprevalence at 1:20 could not be calculated for a further 4 sites examined in 1987. Antibody to B. burgdorferi was also detected in other small mammals at some sites. Such antibody was interpreted as possibly cross-reacting or caused by direct transmission.

Animals↗

PubMed1991

Apparent incompetence of Dermacentor variabilis (Acari: Ixodidae) and fleas (Insecta: Siphonaptera) as vectors of Borrelia burgdorferi in an Ixodes dammini endemic area of Ontario, Canada.

From April to October 1990, white-footed mice, Peromyscus leucopus (Rafinesque), were examined for ectoparasites on Long Point, Ontario, the only endemic area for Ixodes dammini Clifford, Spielman, Piesman & Corwin and Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner known in Canada. Larval and nymphal I. dammini and Dermacentor variabilis (Packard), and adult fleas Orchopeas leucopus (Baker), Epitedia wenmanni (Rothschild), and Ctenophthalamus pseudagrytes Baker were common on trapped mice. Questing ticks were collected by dragging, near the sites of mouse trapping, from April to November 1990. Indirect immunofluorescent assay established that 58.3% of adult, 17.3% of nymphal, and 0.15% of larval I. dammini questing at Long Point were infected with B. burgdorferi, indicating that infected mammalian reservoir hosts are common. None of 593 adult, 2 nymphal, and 4 larval D. variabilis collected while questing were infected; and only 1 of 322 fleas (O. leucopus) removed from white-footed mice was infected. The fact that no unfed adult D. variabilis and only one flea were infected, in a situation where the probability of exposure of hematophagous ectoparasites is moderately high, suggests that this species of tick and the fleas examined are poor vectors for the Lyme disease spirochete.

Animals↗

PubMed1989

Role of Fluosol-DA 20% in prehospital resuscitation.

Fluosol-DA 20% (FDA-20) resuscitation has been proposed for prehospital therapy of hemorrhagic shock (HS). Acute HS (mean arterial pressure 60 mm Hg X 90 min, then 40 mm Hg X 30 min) in 24 splenectomized dogs was treated with 50 ml/kg of lactated Ringer's solution (RL) plus a volume equal to 105% of shed blood volume of FDA-20 (group 1), FDA-20 carrier Annex solution (group 2), or RL (group 3). Cardiopulmonary, hemopoietic, hemodynamic, and organ function parameters were measured preshock, at the end of shock, and at 30 and 60 min, and 24 h after resuscitation. FDA-20 produced effective volume expansion, oxygen delivery, and oxygen consumption. The FDA-20 appeared to affect organ function and cells adversely as reflected by a fall in red cell mass and platelet levels and by a rise in liver enzymes, BUN, and serum creatinine. Both the FDA-20 and Annex solution led to a reduction in serum proteins including serum albumin, serum globulin, immunoglobulin-G, and fibrinogen. These reductions are probably due to an oncotically driven factor which appears to maintain an optimal lymph to plasma oncotic ratio. The hydroxyethyl starch in the FDA-20 and the Annex solution, thus, would drive the plasma proteins into the interstitial space. The prolonged prothrombin times and the activated partial thromboplastin times after FDA-20 may be due, in part, to a reduction in the coagulation proteins, although these were not measured. Pending further studies designed to assess the effects of FDA-20 on possible cellular and multiple organ toxicity, clinical studies are premature and unwarranted.

Animals↗

PubMed1988

Regenerative responses to exchange perfusion.

Isovolemic exchange perfusion of conscious normal and splenectomized rats to a Hct of +/- 3% with the perfluorocarbon based oxygen transport fluid, Fluosol-DA 20%, is characterized by: 1) a greater than projected depression of fibrinogen and the plasma globulins and 2) a rapid regeneration of these and certain other plasma proteins. Similar responses were observed in a study of PFC resuscitation of hemorrhagic shock in splenectomized dogs in which there was a selective depression of the platelets, the plasma globulins, IgG and fibrinogen. In the rats, the red cells and platelets required 14-21 days to return to control levels while the leukocytes returned to normal in 1-2 days. The globulins and fibrinogen exhibited a transient rebound response at 3 and 12 hours post exchange respectively with total protein levels restored to control levels at 48 hours. In the shock study, the leukocytes, which remained at control levels throughout the shock period and for 1 hour post resuscitation were 2.5x control levels at 24 hours. The platelets which were depressed to 20% of control levels following resuscitation remained depressed through the 24 hour time course of the study. Implicit in these results is the possibility that; A) thrombosis and B) immunosuppression may be caused by some component(s) of the perfusion/resuscitation fluid.

Animals↗

PubMed1976

Interference in short-term memory from vocalization: aural versus visual modality differences.

The Peterson and Peterson short-term memory paradigm involves an interpolated task with several potential dimensions from which interference may orginate: Similarity of items and vocalization. Here we assess the relative interference potency of each on material presented either aurally or visually. Interpolated activity consisting of numbers or words was performed either vocally or silently after either aural or visual presentation of nouns, for which recall was tested after 0, 10, and 30 sec. The magnitude of the vocalization interference effect accounted for 59% and 53% of the total variance at 30 and 10 sec, respectively, whereas the variance associated with similarity was negligible. The effect of similarity emerged dramatically only in the visual presentation condition wherein the silent word task created greater interference than the silent number task. Vocal and silent activity produced differential interference, in partial accord with the dual memory hypothesis.

Auditory Perception↗