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Biomedical subjects

D V Wilson

Publications and source records attributed to D V Wilson.

At least 19 recordsLinked to original sources
PubMed2006

Response to nasopharyngeal oxygen administration in horses with lung disease.

REASONS FOR PERFORMING STUDY: Guidelines for administration of oxygen to standing horses are unavailable because previous investigations of the efficacy of oxygen administration to increase arterial oxygenation in standing horses have produced equivocal results. OBJECTIVE: To determine the effect of nasal oxygen supplementation on inspired and arterial blood gas tensions in control horses and those with moderate to severe recurrent airway obstruction (RAO). METHODS: Normal horses (n = 6) and horses during an attack of RAO induced by stabling (n = 6) were studied. Oxygen was administered through either one or 2 cannulae, passed via the nares into the nasopharynx to the level of the medial canthus of each eye. Intratracheal inspired oxygen and carbon dioxide concentration and arterial blood gas tensions were measured at baseline and during delivery of 5, 10, 15, 20 and 30 l/min oxygen. RESULTS: Nasal cannulae and all but the highest oxygen flow rates were well tolerated. Fractional inspired oxygen concentration (F(I)O2) increased with flow but was significantly lower at all flow rates in horses with RAO compared with controls. Arterial oxygen tension (PaO2) was significantly increased (P < 0.001) by all flow rates, but was always lower in RAO-affected animals. At 30 l/min, PaO2 increased to 319 +/- 31 mmHg in control horses and 264 +/- 69 mmHg in horses with RAO. Additionally, a large arterial to end-tidal gradient for CO2 in RAO-affected horses was observed, indicating increased alveolar deadspace ventilation in these animals. CONCLUSIONS: The use of nasal cannulae to deliver oxygen effectively increases both F(I)O2 and PaO2 in horses with moderate to severe RAO. Oxygen flow rates up to 20 l/min are well tolerated, but flow rates of 30 l/min produce occasional coughing or gagging. POTENTIAL RELEVANCE: Oxygen therapy delivered by means of an intranasal cannula is a highly effective means of increasing arterial oxygen tension in horses with respiratory disease. Generally, flows of 10-20 l/min should be effective. If higher flows (20-30 l/min) are necessary, they should be delivered by means of 2 cannulae.

Animals↗
PubMed2004

Pharmacokinetics of combined intraperitoneal and incisional lidocaine in the dog following ovariohysterectomy.

Topical application of local anesthetics provides safe analgesia following abdominal surgery in people. Conservative doses have been utilized to avoid toxicity. Toxic effects are proportional to amount of drug administered and the plasma concentration of the drug, allowing predictions of safety following pharmacokinetic studies. The maximum plasma level, the pharmacokinetics and the safety of lidocaine hydrochloride when administered by the combined intraperitoneal (8 mg/kg i.p. with epinephrine 1:400 000) and incisional (2 mg/kg with epinephrine 1:200 000) routes were studied in six mixed breed dogs following ovariohysterectomy. Rapid uptake of lidocaine produced a peak concentration of 1.45 +/- 0.36 microg/mL (mean +/- SD, range 0.80-1.86 microg/mL) by 0.37 +/- 0.26 h (range 0.11-0.81) after administration. The absorption half-life was 0.13 +/- 0.1 h. Plasma concentrations decreased rapidly and the elimination half-life was 1.17 +/- 0.11 h. No signs of toxicity were observed in these dogs in the 18 h following drug administration. The dose studied generated levels of lidocaine well below toxic.

Administration, Topical↗
PubMed2004

The effects of a single acupuncture treatment in horses with severe recurrent airway obstruction.

REASONS FOR PERFORMING STUDY: Acupuncture may be recommended for horses with 'heaves' because it is being increasingly applied to treat human asthma. Therefore, its efficacy was investigated in horses with this asthma-like disease. OBJECTIVE: To evaluate the efficacy of a single acupuncture treatment for the relief of airway obstruction in heaves-affected horses. METHODS: The efficacy of a single acupuncture treatment was tested in 10 heaves-affected horses, and the effect of removal from the dusty stall environment in 5 heaves-affected horses. Before treatment, horses were stabled to induce airway obstruction and, apart from trips to the laboratory for pulmonary function measurements, they remained stabled for the duration of each treatment. The severity of airway obstruction was quantified by measurement of lung function before treatment (baseline), and at 20, 60, 120 and 240 mins and 24 h after the following treatments administered in random order: halter restraint and patting, a single acupuncture treatment by an experienced acupuncturist, and a single acupuncture treatment using predetermined points (recipe) by a veterinarian with no acupuncture training. In a second study, horses were untreated and remained either in their stall or in a paddock for all measurements of lung function, after baseline readings were made. RESULTS: In the first study, after all treatments, there was a temporal improvement in maximal change in pleural pressure, pulmonary resistance, dynamic compliance, respiratory rate, and tidal volume that lasted less than 24 h. There was no specific effect of acupuncture treatment. In the second study, removal from the dusty environment did not produce an improvement in lung function in the first 6 h. We conclude that most of the improvements in lung function observed in the study were due to handling. CONCLUSIONS: Assessed objectively, a single acupuncture treatment during an attack of heaves causes no more improvement in lung function than does handling the horse. POTENTIAL RELEVANCE: Acupuncture should not replace conventional medical treatments for heaves.

Acupuncture Therapy↗
PubMed2001

A technique for obtaining feedback from students using a computer program in a veterinary anesthesia course.

INTRODUCTION: The College of Veterinary Medicine at Michigan State University has been using computer-aided instructional programs in our pre-clinical veterinary anesthesia course. We describe an embedded feedback collection module (FCM) that facilitates the process of formative evaluation of the program. METHODS: The instructional program was divided into discrete sections. The FCM was accessed easily from all sections of the program. Instructions for use of the FCM were delivered orally to all users of the instructional program and were included in the introduction section of the program. RESULTS: Feedback was obtained from successive classes of veterinary students over four years, using our computer-aided instructional program. Students in each class were required to use the program either in class or for review and to leave at least one comment in the FCM. Of the 653 responses, 293 were positive and expressed appreciation for the program, 209 contained specific comments or suggestions, and 151 were questions relating to the subject material contained within the program. Written survey feedback was also obtained from some students in these classes. CONCLUSION: Our FCM was effective and easy to implement. It proved an easy way to obtain user feedback, which was used in the ongoing process of program design and content improvement.

Anesthesia↗
PubMed2000

Concentration of cardiac troponin I in a horse with a ruptured aortic regurgitation jet lesion and ventricular tachycardia.

An 18-year-old Thoroughbred gelding was evaluated because of sudden onset of ventricular tachycardia and signs of colic. Three years earlier, a diastolic decrescendo murmur, consistent with aortic regurgitation, had been detected, but the horse continued to perform well and compete successfully. Cardiac ultrasonographic examination revealed a defect in the interventricular septum below the aortic root, and serum concentrations of cardiac troponin I (cTnI) were higher than those measured in clinically normal horses. Repeated development of tachyarrhythmia during hospitalization prompted a decision to euthanatize the horse. A ruptured endocardial jet lesion below the aortic valve with formation of a cleft into the interventricular septum was found on necropsy. This report of increased serum cTnI concentrations in a horse with myocardial disease and our other findings suggest that assessment of cardiac troponin concentrations may be a useful tool in the evaluation of horses with suspected myocardial disease.

Animals↗
PubMed1997

Tachykinin receptors in the equine pelvic flexure.

Tachykinins, of which substance P (SP) is the prototype, are neuropeptides which are widely distributed in the nervous systems. In the equine gut, SP is present in enteric nerves and is a powerful constrictor of enteric muscle; in other species, SP is also known to have potent vasodilatory and pro-inflammatory effects. The specific effects of SP are determined by the subtype of receptor present in the target tissue. There are 3 known subtypes of tachykinin receptors, distinguished by their relative affinities for SP and other tachykinins. The distribution of SP binding sites in the equine pelvic flexure was determined using 125I-Bolton Hunter SP (I-BHSP) autoradiography. Most I-BHSP binding sites were determined to be saturable and specific, therefore presumably representing tachykinin receptors. The greatest degree of I-BHSP binding occurred over very small vessels, and over the muscularis mucosae; I-BHSP binding was also intense over the circular muscle of the muscularis externa and mucosa, and present, although less intense, over the longitudinal muscle of the muscularis externa. Competition of I-BHSP with specific receptor agonists for binding sites in the equine pelvic flexure were used to determine the subtypes of tachykinin receptors present. The neurokinin-1 receptor subtype predominated in the equine pelvic flexure, followed by the neurokinin-3 receptor subtype.

Animals↗
PubMed1995

Antigliadin antibody measurement by chemiluminescence ELISA in the diagnosis of coeliac disease.

AIMS: To develop a chemiluminescence enzyme linked immunosorbent assay (ELISA) for the detection of circulating gliadin antibodies in the diagnosis of coeliac disease. To compare this method for linearity and sensitivity with an established colorimetric method. METHODS: Three sets of age and sex matched patient groups were studied: normal controls (patients with no clinical signs of intestinal disorders); gastrointestinal controls (patients with a known gastrointestinal disorder other than coeliac disease); and patients in whom suspected coeliac disease had been confirmed by positive jejunal biopsy. IgG antigliadin antibody (IgG-AGA) and IgA antigliadin antibody (IgA-AGA) titres were determined. RESULTS: Comparison of the colorimetric and chemiluminescence methods showed close correlation of measured antibody levels for both control patient groups. In the coeliac patients correlation of antibody levels measured by both methods was not possible because the colorimetric assay is limited by the spectrophotometer's limits of detection. This problem was overcome by the chemiluminescence method which was linear over a greater range and to far higher values. CONCLUSIONS: The chemiluminescence ELISA performs as well as the colorimetric assay at low and average antibody levels and has the advantage of also giving a numerical value to higher antibody titres. The method was accurate and reproducible in confirming the diagnosis of coeliac disease in patients with positive jejunal biopsy and was capable of monitoring progress of the disease.

Adolescent↗
PubMed1995

Spontaneous loss of HBeAg and development of anti-HBe during long-term follow-up of blood donors found to be HBsAg-positive.

Since 1980, at North London Blood Transfusion Centre 61 (14%) of a total of 442 hepatitis B surface antigen (HBsAg) positive carriers have been hepatitis B e antigen (HBeAg) positive by radioimmunoassay at the time of detection, with 353 (80%) anti-HBe positive. We have undertaken long-term follow-up of infectivity markers in 285 of these 442 HBsAg carriers detected by routine screening. Donors undergoing acute HBV infection were excluded from the analysis. The donor follow-up times ranged from 1.2 to 13.5 years. Regular follow-up samples were obtained and examined for HBsAg, HBeAg, anti-HBe, serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Thirty-five (12.3%) of the 285 carriers were HBeAg-positive when first detected. Eight of these 35 developed anti-HBe during follow-up. At no time did any carrier revert from anti-HBe to HBeAg. When these data were subjected to a Kaplan--Meier analysis an estimated lower quartile time to seroconversion of 3.83 years, and a median seroconversion time of 8.25 years were predicted. This corresponds to a mean rate of 6.5% per annum for the first 25% to seroconvert, and 5.7 for the next 25%.

Blood Donors↗
PubMed1994

Anesthesia and sedation for late-term mares.

Heavily pregnant mares requiring anesthesia present special problems and challenges. The use of short-acting anesthetic agents, combined with inhalational anesthesia, mechanical ventilation, and blood pressure support, will ensure an optimal outcome by maintaining both maternal and fetal homeostasis. The provision of oxygen during recovery to the still gravid mare also is important for fetal survival.

Anesthesia↗
PubMed1994

Histologic and ultrastructural changes after large-colon torsion, with and without use of a specific platelet-activating factor antagonist (WEB 2086), in ponies.

The role of platelet-activating factor (PAF) in mediating the colonic damage that develops after large-colon torsion was studied in 14 ponies. Morphologic changes in areas of the ascending colon and selected abdominal and thoracic viscera after 1 hour of large-colon torsion and 3 to 5 hours of reperfusion were determined, as well as the protective effects of systemic administration of a specific PAF antagonist (WEB 2086). Ponies were selected then allocated at random and in equal numbers to 2 groups that received 1 of 2 treatments prior to induction of large-colon torsion: group 1--control (saline solution), and group 2--WEB 2086 (3 mg/kg of body weight loading dose and 3 mg/kg/h for the remainder of the study). In each pony, full-thickness tissue specimens from the gastrointestinal tract--cecum, pelvic flexure, left and right ventral colon, and right dorsal colon--heart, left lung, liver, left adrenal gland, spleen, and right kidney were collected and histologically evaluated. Edema, mucosal necrosis, and neutrophil infiltration in colonic sections were graded from 0 (normal) to 3 (most severe changes). Sections of liver and lung from 3 ponies in each group, and colon from 1 pony in each group, also were examined by transmission electron microscopy to determine the presence of ultrastructural alterations. Ischemia and reperfusion induced marked changes in all sections of colon in all ponies: moderate to severe submucosal edema, moderate necrosis of the superficial epithelium and lamina propria, and necrosis of the mucosal crypt epithelium. Extravascular neutrophil accumulation was evident in all sections of colon and cecum, but not in other tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Cardiovascular responses to exogenous platelet-activating factor (PAF) in anesthetized ponies, and the effects of a PAF antagonist, WEB 2086.

The effects of exogenous platelet-activating factor (PAF) were determined in anesthetized ponies. Administration of PAF induced a decrease in cardiac index that resulted in systemic hypotension. This was followed by tachycardia, hypertension, and a return of cardiac index to baseline. Pulmonary arterial pressure increased markedly because of pulmonary vasoconstriction. Exogenous PAF also caused leukopenia and thrombocytopenia. The specific PAF receptor antagonist (WEB 2086) blocked all PAF-induced changes. Flunixin meglumine, a cyclooxygenase inhibitor, abolished the pulmonary hypertension and tachycardia, and attenuated the systemic hypotension but did not change the PAF-induced peripheral cellular changes. The PAF antagonist also inhibited platelet aggregation induced by PAF in vitro. The PAF-induced changes are similar to those reported after endotoxin exposure in horses.

Anesthesia, Intravenous↗
PubMed1993

Effect of a specific platelet-activating factor antagonist on cardiovascular and peripheral cellular responses to colonic ischemia and reperfusion in anesthetized ponies.

The role of platelet-activating factor in mediating the cardiovascular and peripheral cellular responses to large-colon ischemia and reperfusion, was explored in anesthetized ponies. A specific platelet-activating factor (PAF) antagonist (WEB 2086) was administered to a group of 6 ponies, and another 6 ponies (controls) were given an equivalent volume of saline solution, prior to 1 hour of large-colon torsion. After correction of the torsion, ponies were monitored during the reperfusion period. Significant (P < 0.05) hypotension and metabolic acidosis developed in all ponies after correction of colonic torsion, cardiac index increased initially, but then decreased significantly (P < 0.05) over the study period. Mean times between correction of torsion and onset of cardiac failure and death were not different between groups. Significant (P < 0.05) thrombocytopenia developed during the reperfusion period in control ponies, but not in WEB-treated ponies. Blood leukocyte concentration in control ponies was more variable and significantly (P < 0.05) decreased immediately upon reperfusion, compared with that in WEB-treated ponies. We conclude that although the cardiovascular responses to colonic ischemia and reperfusion are not prevented by use of a specific PAF-antagonist, specific peripheral cellular responses are mediated by PAF.

Analysis of Variance↗
PubMed1992

Advantages and guidelines for using opioid agonists for induction of anesthesia.

Opioids have a central role in the anesthetic management of small animals, as premedicants, as part of a balanced anesthetic technique, or for the provision of postoperative analgesia. These drugs are safe to use, provide excellent analgesia, and are easily reversible. They cause minimal cardiovascular depression and induce no deleterious renal or hepatic changes. These agents, combined with a sedative, generally provide an ideal anesthetic state.

Anesthesia↗
PubMed1992

Anesthesia for patients with diaphragmatic hernia and severe dyspnea.

Problems facing a patient with severe dyspnea secondary to diaphragmatic herniation are hypoxia, hypercarbia and respiratory acidosis, and cardiovascular instability. It is easy to precipitate a crisis in these patients during anesthetic induction as a result of stress, bad positioning, induction of pneumothorax, or inappropriate anesthetic technique. These patients require a smooth, stress-free perianesthetic period with preoxygenation, positioning with the affected side down, rapid intravenous induction, endotracheal intubation, and mechanical ventilation. Maintenance with isoflurane is preferred, and nitrous oxide should be avoided. Close monitoring of the cardiovascular and pulmonary systems is essential. Recovery from anesthesia should include oxygen supplementation, pleural drainage, and local analgesia if required.

Anesthesia↗
PubMed1992

Anesthesia for patients with head trauma.

Patients undergoing anesthesia soon after head trauma are at great risk for further neural damage during the anesthetic, especially if the head injury is severe or the anesthetic technique is suboptimal. Secondary complications of the anesthetic that are often lethal include hypoventilation, increases in ICP, airway obstruction, and brain-stem herniation. Anesthetic management of patients with head injury must include intravenous induction with barbiturates or narcotics, smooth endotracheal intubation, controlled ventilation with oxygen, and minimal amounts of inhalational agents. It is important to position the patient so that jugular veins are not occluded, in about 10 degrees head up position, and to avoid inducing patient coughing and straining. Recovery from anesthesia should be quiet and rapid, with the maintenance of a clear airway and the use of as little depressant medication post-operatively as possible. Oxygen should be provided.

Anesthesia↗
PubMed1992

Anesthesia for patients with severe systemic debilitation.

Any patient presenting for anesthesia and surgery who has a severe debilitating problem is at great risk for a prolonged recovery, renal failure, or hypotension. A stable hemodynamic state should be maintained. Fluid homeostasis should be ensured. Anesthetic induction techniques using narcotics and benzodiazepines are my preferred approach, with maintenance of anesthesia incorporating isoflurane, narcotics, or both or the use of regional anesthesia.

Anesthesia↗