Comments on council report.
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Education, Veterinary↗
Biomedical subjects
C A Rawlings
Publications and source records attributed to C A Rawlings.
Further development of the baboon as a model for acute schistosomiasis.
Baboons develop a syndrome, including eosinophilia and transient fever, after infection with cercariae of Schistosoma mansoni that is consistent with the human syndrome of acute schistosomiasis. Radiotelemetry can be used to follow the course of fever in infected baboons. Individual variations in intensity of disease were noted in baboons. These symptoms and signs were more closely linked to the onset of oviposition by the newly matured worms than they were to the presence of migrating schistosomula or maturing worms. The baboon is concluded to be a suitable and useful model for human acute schistosomiasis mansoni.
Acute Disease↗
Applications of a semitendinosus muscle flap in two dogs.
The proximal half of the semitendinosus muscle can be used as a versatile vascularized local transposition flap to reconstruct anatomic faults in the adjacent perineum in dogs. The flap is easy to dissect, and the arc of rotation is considerably beyond the midline. The location, size, and direction of the major vascular pedicle from the caudal gluteal artery is conducive to dependable flap perfusion.
Animals↗
Gene sequence of feline tumor necrosis factor alpha.
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Amino Acid Sequence↗
Postadulticide pulmonary hypertension of canine heartworm disease: successful treatment with oxygen and failure of antihistamines.
Postadulticide pulmonary hypertension mechanisms and treatment with antihistamines and supplemental oxygen were studied in eight dogs with heartworm disease. To ensure severe postadulticide thromboembolism, additional heartworms (either 20 or 40 into 4 dogs each) were transplanted into naturally infected dogs before thiacetarsamide treatment. During pentobarbital anesthesia, 2 pulmonary hemodynamic studies were conducted on each dog with a sequence of baseline, hypoxia with FlO2 = 10%, hyperoxia with FlO2 = 100%, a second baseline, treatment with either diphenhydramine (D) or cimetidine (C), and another hypoxia. All dogs were pulmonary hypertensive, with each dog having a mean pulmonary arterial pressure (PPA) greater than 20 mm of Hg. Mean PPA increased from baseline conditions (25.0 +/- 4.5 SD for D and 24.3 +/- 4.4 for C) to hypoxia (28.5 +/- 4.7 for D and 28.4 +/- 3.7 for C), and decreased during hyperoxia (16.9 +/- 3.0 for D and 17.4 +/- 3.0 for C), respectively. Neither antihistamine reduced PPA at normoxia. The degree of pulmonary hypertension when breathing room air increased even more during hypoxia, and this increase was not attenuated by either antihistamine. Histamine did not appear to mediate pulmonary hypertension during postadulticide thromboembolism, nor to modify the hypoxia-mediated pulmonary hypertension at this disease stage. Because baseline PO2 was low (66.6 +/- 11.7 mm of Hg for D and 69.4 +/- 14.2 for C) and because PPA decreased during administration of oxygen, the pulmonary hypertension was mostly hypoxia-induced. In addition to the arterial lesions, much of the pulmonary hypertensive mechanism was an active and reversible vasoconstriction in response to hypoxia caused by the secondary lung disease.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Lameness in a mare with signs of arteriovenous fistula.
A 5-year-old mare was evaluated for lameness and swelling of the right forelimb. Clinical findings, including peripheral edema, venous pulsation, palpable thrill in the cephalic vein, disparate arteriovenous oxygen tension differences between the left and right forelimbs, and Branham sign, were suggestive of arteriovenous fistula. Failure to identify the fistula by angiography was attributed to closure of the shunt during anesthesia. Surgical exploration of the affected limb to identify the shunt also was unsuccessful.
Animals↗
A computer model to study norepinephrine-induced oscillations of contraction in tail arteries of spontaneously hypertensive stroke-prone rats.
The purpose of this study is to develop a computer model of oscillatory contractions in isolated arteries from the tails of spontaneously hypertensive, stroke-prone rats (SHRSP). The computer simulation incorporates biologic data from experiments and mathematic expressions derived from an electric circuit model of the biologic system. The model characterizes the cellular mechanisms which have been proposed to be responsible for the oscillatory activity. Results indicate the ability of the model to provide results which closely match experimentally obtained data.
Animals↗
Lidocaine treatment of dogs with Escherichia coli septicemia.
Effects of lidocaine on organ localization of neutrophils and bacteria and on hemodynamic and metabolic variables were determined during septic shock in dogs. Twelve anesthetized dogs were infused with 10(10) Escherichia coli/kg of body weight through a portal vein catheter over a 1-hour period. Six of these 12 dogs were treated with 2 mg of lidocaine HCl/kg (6 mg/kg/h) 15 minutes after the bacterial infusion had begun. Six dogs not given E coli (surgical controls) were given saline solution at the same rate as the bacterial and lidocaine infusions. Over 4 hours, nontreated dogs with septicemia developed systemic hypotension, decreased cardiac output, increased portal pressure, increased serum alanine transaminase activity, increased liver extravascular water, increased liver glycogen depletion, and decreased PaO2, compared with control dogs. Accumulations of polymorphonuclear leukocytes and E coli were found in the liver and lungs of dogs with septicemia. Lidocaine treatment did not alter the hemodynamic measurements and resulted in metabolic acidosis and hypoalbuminemia. Decreased numbers of E coli were recovered from the liver of lidocaine-treated dogs, whereas increased numbers of organisms were recovered from the blood. Neutrophil sequestration was increased in the liver, but not the lungs of lidocaine-treated dogs.
Animals↗
Lesions in dogs following renal transplantation and immunosuppression.
Renal allografts were transplanted into 20 dogs (12 beagles, eight mongrels) following a prescribed protocol for pre-transplantation blood transfusions and kidney exchange. Immunosuppressive therapy (azathioprine and prednisone) was modified as needed for each dog. Seven of the beagle dogs survived for 1 year and were then euthanized; all other dogs died or were euthanized prior to 1 year post-transplantation. Graft rejection and renal failure were the greatest causes of mortality. Renal lesions which contributed to the death of some animals included renal vein thrombosis, nephrosis, and pyelonephritis. Inflammation of the lower respiratory tract (bronchitis, pneumonia, and pleuritis) was a contributory cause of death in some dogs. Cystitis and ureteritis occurred in almost half of the dogs. Prostatitis was seen in six of the 16 male dogs. Adrenal cortical atrophy, parathyroid gland hyperplasia, and bone marrow hypocellularity were seen in a majority of the dogs which survived 1 year.
Animals↗
Heartworm disease: solving some problems and illuminating others.
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Animals↗
Escherichia coli-induced lung and liver dysfunction in dogs: effects of flunixin meglumine treatment.
Twelve dogs were infused with 10(10) Escherichia coli/kg of body weight through a portal vein catheter over a 1-hour period; 6 dogs were treated with flunixin meglumine (1 mg/kg) 15 minutes after the infusion had begun. Six dogs (controls) were infused with a comparable volume of sterile saline solution over the same period. Over a 4-hour monitoring period, nontreated septicemic dogs developed systemic hypotension, decreased cardiac output, increased portal pressure, increased serum alanine transaminase values, increased extravascular liver water, increased liver glycogen depletion, and decreased arterial oxygen tension compared with control dogs. Accumulations of polymorphonuclear leukocytes and E coli were found in the livers and lungs of septicemic dogs. Flunixin meglumine treatment prevented systemic hypotension and hypoxemia, reversed the early but not the late stages of portal hypertension, and decreased E coli concentrations in the lungs. Other effects of treatment were not noticed.
Animals↗
Elaeophorosis in white-tailed deer: pathology of the natural disease and its relation to oral food impactions.
The lesions of naturally occurring elaeophorosis in white-tailed deer (Odocoileus virginianus) were studied. Arterial changes caused by adult Elaeophora schneideri occurred mainly in cephalic arteries and were characterized by circumferential intimal thickening, disruption of the internal elastic lamina, and verminous thrombosis. Microfilariae caused focal necrosis and fibrosis in the myocardium, but produced only minor changes in other tissues. Radiographic studies indicated that E. schneideri can cause impairment of the cephalic arterial circulation in white-tailed deer. Eleven of 14 (78%) infected deer had oral food impactions, with sublingual impactions being most common. Seven deer with impactions had other oral pathologic conditions, such as gingivitis, loose or absent premolar and/or molar teeth, and remodeling and/or lysis of mandibular bone. The evidence indicates a relation between food impactions and infection by E. schneideri in white-tailed deer, but no definitive connection was established.
Animals↗
The fecundity of Schistosoma mansoni in chronic nonhuman primate infections and after transplantation into naive hosts.
Adult Schistosoma mansoni worms were transplanted from 8 nonhuman primates with chronic infections into 8 naive recipients, in an effort to test the hypothesis that worm fecundity reduction in chronic infections is the result of host immunity or some other host effect. Techniques for perfusing living donors without the added use of anti-schistosomal drugs and for reducing the likelihood of post-operative bacterial endotoxemia and septic shock are described. Fecundity values in terms of eggs per day per female worm were obtained for the worms in their original and in their new hosts and compared. In 3 experiments, perfusions were incomplete and the donors were saved, enabling direct comparisons of fecundity to be made in subpopulations of worms in both their original and new hosts, after equal life spans. In only 1 of the 8 transplantations was there a clear increase in fecundity after surgical introduction into a naive host. Therefore, these experiments fail to support the hypothesis that reduced fecundity of S. mansoni worms in permissive nonhuman primate hosts is a reversible result of host immunity or some other host-derived factor. Despite this negation, further evidence for reduced worm fecundity in older infections was obtained. In the absence of in vivo evidence for immune-mediated antifecundity, worm senescence is the most likely explanation for this finding, with irreversible immune damage to the worms being a less attractive alternative hypothesis.
Animals↗
Smooth muscle proliferation in chronically injured canine pulmonary arteries is reduced by a potent platelet aggregation inhibitor U-53,059.
Dirofilaria immitis (DI) infection chronically injures canine pulmonary arteries. This injury produces endothelial cell loss, platelet/leukocyte adhesion, and smooth muscle proliferation. In the present study we assessed the effect of the cyclooxygenase inhibitor, U-53,059, on platelet function, platelet kinetics, coagulation, and smooth muscle proliferation in DI infected dogs. Platelet aggregation to the combination of arachidonic acid/ADP was significantly inhibited by U-53,059. Coagulation and hematologic parameters were not effected by either DI infection or U-53,059 treatment. Platelet survival and the number of platelet dense granules were reduced in DI infection. Quantification of the lesions demonstrated that U-53,059 reduced both severity and density compared to non-treated dogs. U-53,059 is a potent and effective inhibitor of platelet aggregation which modifies smooth muscle proliferation produced by chronic vascular injury.
Animals↗
Pulmonary manifestations of heartworm disease.
The clinical signs associated with heartworm disease are the result of changes in the pulmonary arterial system. These clinical signs are the result of either pulmonary hypertension or lung parenchymal disease associated with vascular changes. An increase in pulmonary arterial pressure produces an increase in right ventricular afterload, which may lead to exercise intolerance, syncope, and right-sided congestive heart failure. Coughing, dyspnea, and hemoptysis are the results of pulmonary parenchymal disease.
Adrenal Cortex Hormones↗
Kidney graft survival in transfused and nontransfused sibling beagle dogs.
In 6 pairs of sibling Beagle dogs, 1 kidney was exchanged between pairs, and contralateral nephrectomy was done. Previously, one dog of each pair was given blood transfusions from the donor of its allograft. All dogs were given azathioprine and prednisone postoperatively for immunosuppression. Four of 6 dogs given pretransplantation transfusions were healthy 1 year after surgical manipulation was done, and 2 died for reasons other than graft rejection. Of the 6 dogs that were not given pretransplantation transfusions, 3 were healthy after 1 years, but 2 were euthanatized because of graft rejection, and the last was euthanatized because of both graft rejection and intussusception. Other complications in these dogs were leukopenia (7 dogs), interdigital abscesses (2 dogs), urinary infection (3 dogs), and renal vein thrombosis (1 dog). Considering the lack of alternative methods for effective therapy for chronic renal failure in dogs, results of this study seem encouraging for selective use of renal transplantation, clinically. This study supports previous reports which indicated that pretransplantation transfusion enhanced graft survival in dogs.
Animals↗
Surgical transplantation of adult Dirofilaria immitis to study heartworm infection and disease in dogs.
Heartworm infections were established in dogs by surgical transplantation of adult heartworms into the external jugular vein. The heartworms were obtained from donor dogs that had been infected with large numbers of infective larvae. This heartworm model standardized the infection with a known number of heartworms of a known age and sex. This paper presents the methods for obtaining heartworms from donor dogs, for selection of recipient dogs, and for transplantation of heartworms.
Animals↗
Pharmacokinetics of flunixin meglumine in dogs.
The pharmacokinetics of flunixin meglumine, a potent nonsteroidal anti-inflammatory agent, were studied in 6 intact, awake dogs. Plasma samples were obtained up to 12 hours after IV administration of flunixin meglumine. Flunixin concentration was determined, using high performance liquid chromatography. Plasma data best fit a 2-compartment model. Distribution half-life was 0.55 hour; elimination half-life was 3.7 hours; volume of distribution (area) was 0.35 L/kg; volume of distribution at steady state was 0.18 L/kg; volume of the central compartment was 0.079 L/kg; and total body clearance was 0.064 L/hr/kg. Flunixin concentrations obtained over a 6-hour period in 3 dogs with septic peritonitis did not differ significantly from those obtained from healthy dogs.
Animals↗