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Biomedical subjects

Gordon W Brumbaugh

Publications and source records attributed to Gordon W Brumbaugh.

7 recordsLinked to original sources

Pharmacokinetics and clinical effects of a subanesthetic continuous rate infusion of ketamine in awake horses.

OBJECTIVE: To determine the pharmacokinetics and clinical effects of a subanesthetic, continuous rate infusion of ketamine administered to healthy awake horses. ANIMALS: 8 adult horses. PROCEDURES: Ketamine hydrochloride was administered to 2 horses, in a pilot study, at rates ranging from 0.4 to 1.6 mg/kg/h for 6 hours to determine an appropriate dose that did not cause adverse effects. Ketamine was then administered to 6 horses for a total of 12 hours (3 horses at 0.4 mg/kg/h for 6 hours followed by 0.8 mg/kg/h for 6 hours and 3 horses at 0.8 mg/kg/h for 6 hours followed by 0.4 mg/kg/h for 6 hours). Concentration of ketamine in plasma, heart rate, respiratory rate, blood pressure, physical activity, and analgesia were measured prior to, during, and following infusion. Analgesic testing was performed with a modified hoof tester applied at a measured force to the withers and radius. RESULTS: No signs of excitement and no significant changes in the measured physiologic variables during infusion rates of 0.4 and 0.8 mg of ketamine/kg/h were found. At 6 hours following infusions, heart rate and mean arterial pressure were decreased, compared with preinfusion measurements. An analgesic effect could not be demonstrated during or after infusion. Pharmacokinetic variables for 0.4 and 0.8 mg/kg/h infusions were not significantly different. CONCLUSIONS AND CLINICAL RELEVANCE: Ketamine can be administered to awake horses at 0.4 or 0.8 mg/kg/h without adverse behavioral effects. The observed pharmacokinetic values are different than those reported for single-dose IV bolus administration of this drug.

Analgesia↗

Use of antimicrobials in wound management.

Antimicrobial medication should be considered an adjunct to the general care of wounds rather than a substitute for lavage, drainage, or other physical care intended to promote healing. Judicious use is based on results of diagnostic procedures and the professional judgment of the attending veterinarian. Organisms that contaminate or infect wounds of horses are similar to those that can affect human patients, such that personal hygiene and protection are important when caring for these equine patients, because attendants can easily be exposed to them. Although those organisms are considered to be ubiquitous, the inoculum that may be present on or in an infected wound may be substantially greater than that encountered during other daily activities of the veterinarian. Proper disposal of the bandage materials and personal protective clothing is important. Bacterial resistance is one of many "survival tactics" of bacteria and has been an important clinical consideration for physicians and veterinarians since antimicrobial drugs were discovered. Controversies and insufficient understanding of bacterial resistance abound, however. The entirety of the subject is beyond the scope of this article, but it is important to the veterinary profession and for the formulation of wound management in horses. We and our animal patients live in a world populated by microbial organisms of various types. Resistance among bacteria is likely to continue to be a clinical consideration in the future as it has been during the past 60 to 70 years. As veterinarians, we must recognize the zoonotic nature of resistance and implement biosecurity procedures to protect ourselves, other people in contact with those pathogens, and our patients. We must also recognize the merits of judicious targeted use of antimicrobial drugs and apply appropriate principles during the course of professional care for the well-being of our animal patients.

Animals↗

Susceptibility of Mycobacterium avium sbsp paratuberculosis to monensin sodium or tilmicosin phosphate in vitro and resulting infectivity in a murine model.

This study was designed to determine the susceptibility in vitro and infectivity of 1 field isolate of Mycobacterium avium sbsp paratuberculosis after exposure to monensin sodium and tilmicosin phosphate. Minimum inhibitory concentrations (0.39 microg monensin sodium/mL; 1.60 microg tilmicosin phosphate/mL) were determined in quintuplicate. Organisms were then incubated with 3 different concentrations of each medication for 3 different lengths of time, then washed and resuspended in sterile physiologic saline and injected intraperitoneally into mice that were genetically susceptible to infection. Mice were euthanatized 50 d later and the number of hepatic granulomas was used as the indicator of infectivity. Neither time of incubation nor concentration of medication had any effect on the infectivity of the organisms. Monensin sodium significantly reduced the number of hepatic granulomas in genetically susceptible mice while tilmicosin phosphate did not. Antimycobacterial activity of monensin sodium suggests that the role of monensin in the control of bovine paratuberculosis should be evaluated further.

Animals↗

How to respond to adverse drug reactions.

Adverse drug reactions (ADRs) are part of the risks, professional responsibilities, and liabilities inherent to veterinary medicine. The incidence of proven ADRs is not known, but veterinarians should anticipate, plan, and practice a response for patients that experience adverse reactions. The attending veterinarian should work closely with professional services personnel at pharmaceutical manufacturers to provide care for those patients, to investigate causes of ADRs, and to factually improve reports of ADRs that can be of considerable medicolegal benefit to the client and the profession.

Animals↗

Neonatal adjustments.

Pharmacodynamic responses by neonates are the same as those for adults, but physiologic differences and pathophysiologic changes can affect pharmacokinetic values sufficiently to require adjustments in dosage regimens used for calves. Adjunctive care may be necessary for some patients to correct or maintain perfusion and temperature of tissues so that absorption and distribution may be adequate. Intravenous administration may be the only route appropriate for some critically ill patients. Anatomic sites and formulation of products administered by extravascular parenteral routes markedly can affect absorption of those products and subsequent clinical response to treatment.

Animals↗

Effect of tilmicosin on chemotactic, phagocytic, and bactericidal activities of bovine and porcine alveolar macrophages.

OBJECTIVE: To evaluate chemotactic, phagocytic, and bactericidal activities of bovine and porcine alveolar macrophages (AM) exposed to tilmicosin. ANIMALS: 12 healthy calves and 12 healthy pigs. PROCEDURES: Lungs were obtained immediately after euthanasia; AM were collected by means of bronchoalveolar lavage and density gradient centrifugation. Chemotactic activity was evaluated by exposing AM to lipopolysaccharide or macrophage inhibitory peptide during incubation with tilmicosin. Phagocytic activity was evaluated by incubating AM with tilmicosin for 24 hours and then with tilmicosin-resistant Salmonella serotype Typhimurium. Bactericidal activity was evaluated by incubating AM with tilmicosin (0, 10, or 20 microg/ml for bovine AM; 0 or 10 microg/ml or 10 microg/ml but washed free of tilmicosin for porcine AM) and then with Mannheimia haemolytica (bovine AM) or with Actinobacillus pleuropneumoniae or Pasteurella multocida (porcine AM). RESULTS: Tilmicosin had no significant effects on chemotactic or phagocytic activities of bovine or porcine AM. The time-course of bactericidal activity was best described by polynomial equations. Time to cessation of bacterial growth and area under the time versus bacterial number curve were significantly affected by incubation of AM with tilmicosin. CONCLUSIONS AND CLINICAL RELEVANCE: Results show that bactericidal activity of bovine and porcine AM was enhanced by tilmicosin, but not in proportion to the reported ability of AM to concentrate tilmicosin intracellularly. With or without exposure to tilmicosin, the time-course of bactericidal activity of bovine AM against M haemolytica and of porcine AM against A pleuropneumoniae or P multocida was too complex to be reduced to a simple linear equation.

Actinobacillus pleuropneumoniae↗

Effectiveness of a unique dihydropyridine (BAYTG 1000) for prevention of laminitis in horses.

OBJECTIVE: To determine whether a unique dihydropyridine (BAYTG 1000) would be beneficial in preventing laminitis in horses. ANIMALS: 16 clinically normal adult horses. PROCEDURE: 8 pairs of horses were used in a controlled double-blind study, using sex- and age-matched horses randomly assigned to treatment or control groups. Horses were subjected to carbohydrate overload to induce laminitis. Treated horses were administered BAY TG 1000 (30 mg/kg, PO, q 24 h) for 3 days. Hoof wall surface temperature (HWST) and lameness were recorded at 4-hour intervals. The HWST was adjusted on the basis of time of onset of lameness and evaluated, using a repeated-measures ANOVA. Lameness 8 hours after onset and clinical status 72 hours after onset of lameness were evaluated, using Mann-Whitney procedures. RESULTS: Analysis revealed that BAYTG 1000 did not decrease the incidence of lameness but significantly ameliorated prodromal hypothermia, lessened the severity of lameness 8 hours after onset of lameness, and improved the clinical status of horses 72 hours after onset of lameness. CONCLUSION AND CLINICAL RELEVANCE: Results support the conclusion that BAYTG 1000 was protective when used in prevention of laminitis. The drug decreased severity and improved clinical status (recovery) of induced lameness, which was interpreted to mean that the drug's actions were on mechanisms important but secondary to primary causal mechanisms of laminitis. Therefore, drugs that enhance digital perfusion via alteration of rheologic activity may have potential use in the prevention and management of laminitis in horses.

Animals↗