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Biomedical subjects

H E Garner

Publications and source records attributed to H E Garner.

At least 37 records · Page 2Linked to original sources
PubMed1986

Ultrastructural study of the equine cecum during onset of laminitis.

The morphologic and pathologic changes which occurred within the cecal mucosa of 4 horses during the onset of laminitis were determined from cecal biopsy materials obtained via a cecal fistula; the laminitis was induced with carbohydrate overload. The cecal epithelial mucosa specimens were obtained at 0 (base line), 24, 32, 48, and 72 hours after horses were given carbohydrate overload, and these were fixed and subsequently photographed. Changes in the cecal epithelium were examined by transmission electron and scanning electron microscopies. These histopathologic changes indicated that the mucosal barrier was substantially damaged by the carbohydrate overload.

Animals↗
PubMed1984

Arterial oxygen and carbon dioxide tensions in conscious laterally recumbent ponies.

Six adult ponies were trained calmly to assume and maintain left lateral recumbency without the use of sedative or immobilising agents. During a 30 min recumbent period, pHa, arterial oxygen and carbon dioxide tensions (PaO2 and PaCO2) and heart and respiratory rates were monitored at regular intervals to evaluate ventilatory response. Overall, there were no statistically significant differences found between mean control and recumbent or final standing values. When lightweight ponies were compared to heavyweight ponies, only mean PaO2 at 10 mins recumbency was different. This information supports the hypothesis that ventilation impairment during the first 30 mins of equine general anesthesia is primarily drug-mediated, rather than initiated by recumbency per se.

Animals↗
PubMed1982

Plasma volume, electrolyte, and endocrine changes during onset of laminitis hypertension in horses.

Acute laminitis-hypertension was produced by carbohydrate overloading of the gastrointestinal tract in 12 adult horses. Obel grade 3 (OG3) lameness developed 40 hours (+/- 3.5, SEM) after overfeeding. At OG3 lameness, mean plasma volume was significantly decreased (P less than 0.005) when compared with base-line values. Before OG3 lameness, transient decreases in serum phosphorus and calcium were recorded. Mild hyponatremia also developed before OG3 lameness and persisted. After establishment of OG3 lameness, persistent hypokalemia and increased plasma aldosterone concentration occurred coincidently. Transient increase in plasma hydrocortisone (cortisol) and renin activity and transient hypochloremia were also recorded during the syndromal phase. Changes in plasma volume and serum electrolytes are discussed and related to the pathogenesis of acute equine laminitis. The alterations in plasma renin activity and aldosterone concentration were interpreted as homeostatic adjustments to fluid and electrolyte imbalances. Differences between the horse and pony during onset of experimental alimentary laminitis are also discussed.

Acute Disease↗
PubMed1982

Radioimmunoassay for the detection of antigen-specific IgM, IgG, and IgA in equine sera.

A radioimmunoassay was developed to discriminate immunoglobulin (Ig) classes specific for the J-5 mutant of Escherichia coli (serotype O:111-B4). Adult horses were periodically inoculated IM with a nonviable suspension of the J-5 mutant emulsified in Freund's incomplete adjuvant. Before and after the horses were inoculated, sera were collected sequentially and examined by radioimmunoassay. Rabbit anti-(horse) Ig and [125I]protein A served as the indicator system. Antigen-specific IgM, IgG, and IgA were observed to follow a classic immune response. The radioimmunoassay offers a valuable tool for the discrimination of circulating, antigen-specific Ig in the horse.

Animals↗
PubMed1982

Hemodynamic effects of prostacyclin (prostaglandin I2) in conscious ponies.

The infusion (IV) of prostacyclin (PGI2) into conscious ponies resulted in systemic arterial hypotension and tachycardia. Mean systemic arterial pressure decreased from 103.3 mm of Hg to 88.5 mm of Hg when 125 ng of PGI2/kg/minute was infused, and heart rate increased from 55.0 to 102.0 beats/minute. When 208 ng of PGI2/kg/minute was infused, mean systemic arterial pressure decreased from 103.3 to 78.0 mm of Hg and heart rate increased from 55.0 to 109.3 beats/minute. There were no significant alterations in pulmonary arterial pressure, lactate, PCV, total WBC count, platelet count, serum lactic dehydrogenase, and acid phosphatase activities, or rectal temperature at either dosage. The ponies became anxious and difficult to manage during the infusion.

Acid Phosphatase↗
PubMed1982

Renal function of the pony and the horse.

Simultaneous renal clearances of inulin (CIN), p-aminohippurate (CPAH), and creatinine (CCR) were measured in hydrated mares (6 ponies and 2 horses). The CIN and CPAH were determined during steady-state infusion at 3 different infusion rates. A 6-fold change in plasma IN concentration did not produce alteration in CIN, nor was there a difference between the ponies and horses (P greater than 0.2). The overall average (mean +/- SEM) was 190.6 +/- 5.89 ml . min-1 . 100 kg of body weight-1. There was no difference noted between simultaneous CIN and CPAH. Clearance of PAH remained essentially constant during the change in plasma PAH from 0.33 mg/dl to 5.27 mg/dl. The extraction ratio of PAH for the nonanesthetized pony was 0.966. Effective renal plasma flow (CPAH) of the pony exceeded that of the horse.

Aminohippuric Acids↗
PubMed1981

Cardiopulmonary effects of clenbuterol in the horse.

Clenbuterol, a bronchospasmolytic agent (beta 2 agonist) was studied in terms of its hemodynamic and airflow response in eight, healthy horses. Four animals were instrumented to record intrapleural pressure and air flow, these were used to compute pulmonary resistance, peak flow rates, and tidal volumes. Four animals were instrumented to record pulmonary arterial pressure, carotid arterial pressure, cardiac output, and arterial gas tensions. After control values were recorded, clenbuterol (0.8 microgram/kg) was intravenously administered to each horse in each experiment group. Following clenbuterol administration, non-elastic resistance of the lung or pulmonary resistance significantly decreased, 33.6% reduction at 10 min post-clenbuterol. Pulmonary resistance remained lowered during the entire procedure and showed no tendency of returning toward control values by 3 h post-clenbuterol. Within 30 sec following clenbuterol injection carotid arterial pressure decreased (mean pressure decrease 28.2%). Accompanying the change in arterial pressure, the heart rate drastically increased, 99.0%. Both changes were transient and returned to control ranges within 2 min. Clenbuterol appears to be effective in reducing non-elastic resistance of the lung, however intravenous administration to an animal with pre-existing cardiovascular or cardiopulmonary disease should be avoided.

Airway Resistance↗
PubMed1981

Haematological changes during development of acute laminitis hypertension.

Experimental carbohydrate overload of 15 horses resulted in consistent haematological changes during development of laminitis hypertension. Significant alterations in packed cell volume, leucocyte differential count, serum glucose levels and protein values occurred before onset of Obel grade 3 lameness and hyperkinetic circulatory state. Blood platelets were significantly decreased 8 h after the onset of severe lameness. Findings in this study were indicative of haemoconcentration due to compartmental fluid shifts and leucocytic stress response consistent with increased circulating adrenoglucocorticoids and/or catecholamines.

Acute Disease↗
PubMed1981

Prevention of endotoxin-induced arterial hypoxaemia and lactic acidosis with flunixin meglumine in the conscious pony.

Bacterial endotoxin injected intravenously into conscious ponies produced alterations in cardiopulmonary and gastrointestinal function. Specifically, tachypnoea, dyspnoea, hypoxaemia, colic, lactic acidosis and diarrhoea resulted from administration of 10 micrograms/kg Escherichia coli endotoxin. Pretreatment of the ponies with a potent prostaglandin synthetase inhibitor, flunixin meglumine, prevented these ill effects of endotoxin.

Acidosis↗
PubMed1981

Endotoxemia following experimental intestinal strangulation obstruction in ponies.

Experimental small intestinal strangulation obstruction was produced in anesthetized ponies. The limulus amoebocyte lysate test demonstrated the presence of endotoxin in the general circulation 60 and 120 minutes following restoration of mesenteric blood flow. Mucosal degeneration, with loss of villus epithelial cells, was demonstrated coincident with endotoxemia. The findings were consistent with an ischemia-mediated alteration in the intestinal barrier to endotoxin.

Animals↗
PubMed1980

Lactic acidosis and arterial hypoxemia during sublethal endotoxemia in conscious ponies.

Effects of a sublethal IV dose (10 micrograms/kg of body weight) of Escherichia coli endotoxin were studied in 7 conscious ponies. Arterial blood gases and plasma lactic acid were determined periodically throughout the 180 minutes of the study. Arterial hypoxemia occurred within 5 minutes despite intense hyperventilation. Colic and diarrhea occurred in all ponies within 30 minutes after endotoxin administration. Metabolic acidosis developed within 30 minutes and persisted throughout the study, indicating widespread reduced tissue perfusion.

Acidosis↗
PubMed1980

Effect of intraluminal oxygen in intestinal strangulation obstruction in ponies.

This study examined the effect of intraluminal oxygen administration on mucosal morphology following intestinal strangulation obstruction (ISO) in anesthetized ponies. The ISO was produced by ligation of the intestinal vasculature in 5 ponies for 50 minutes and 2 ponies for 90 minutes. Two ponies served as controls. Light and scanning electron microscopic examination of intestinal biopsy specimens revealed progressive mucosal degeneration following ISO in nontreated intestines, whereas high magnification scanning electron microscopic examination documented subtle evidence of microvilli disruption 120 minutes following ISO in oxygen-treated intestines.

Animals↗
PubMed1979

Orgotein in equine navicular disease: a double blind study.

Fourteen horses (7 treated with orgotein and 7 treated with a placebo) with navicular disease were studied on a double blind basis. All 14 horses had clinical and radiographic evidence of navicular disease. Orgotein and the placebo were administered by juxtabursal injection. Of the 7 orgotein-treated horses, 3 responded but none of the 7 placebo-treated horses responded. The difference was statistically significant (P less than 0.05).

Animals↗