Search Results

You are looking at 1 - 10 of 73 items for

  • Author or Editor: J. A. Smith x
  • Refine by Access: All Content x
Clear All Modify Search

SUMMARY

A sublethal dose of ethylene glycol was administered orally to 3 groups of dogs; dogs of a control group were given distilled water instead. Renal cortical biopsy samples were obtained from dogs of experimental and control groups at various times after treatment. Tissue was examined by use of light microscopy and transmission electron microscopy. In dogs of the control group, the light and electron microscopic appearances of tissue were within normal limits at all sample collection hours. In dogs of the experimental groups, renal corpuscular structure remained within normal limits by use of light and electron microscopy throughout the study, though morphologic change was seen in other structures of the cortex. Light microscopic lesions first appeared at 12 hours, and were similar to those reported in the literature. Ultrastructural lesions were first observed in the 5-hour samples, and similar to the light microscopic lesions, were most common in the proximal convoluted tubules (pct). Initial pct cellular changes included vacuolization of cells and distention of the parabasal extracellular spaces; pct cellular lesions seen in later-hour samples included formation of apical buds and cellular rupture. Internalization or sloughing of the pct brush border was not observed. Distal convoluted tubules (dct) were frequently dilated and/or packed with cellular debris. A few dct cells had degenerative or necrotic changes. In pct and dct, abnormal cells were frequently flanked by normal or nearly normal cells. During later hours, a few cells with types of changes first observed in early hours continued to be observed, implying ongoing response of cells to the toxin.

Free access
in American Journal of Veterinary Research

Summary

Intranasal (in) and intratracheal (it) oxygen administration techniques were compared by measuring inspired oxygen concentrations ( FI O 2 ) and partial pressures of arterial oxygen ( Pa O 2 ) in 5 healthy dogs at various in (50, 100, 150, and 200 ml/kg of body weight/min) and it (10, 25, 50, 100, 150, 200, and 250 ml/kg/min) oxygen flow rates. Intratracheal administration of oxygen permitted lower oxygen flow rates than in administration. Each it oxygen flow rate produced significantly higher FI O 2 and Pa O 2 than the corresponding in flow rate. An it oxygen flow rate of 25 ml/kg/min produced FI O 2 and Pa O 2 values equivalent to those produced by an in oxygen flow rate of 50 ml/kg/min. An it oxygen flow rate of 50 ml/kg/min produced FI O 2 and Pa O 2 values equivalent to those produced by in oxygen flow rates of 100 and 150 ml/kg/min. All it oxygen flow rates ≥ 100 ml/kg/min produced FI Q 2 and Pa O 2 values that were greater than FI O 2 and Pa O 2 values produced by in oxygen flow rates of 200 ml/kg/ min.

The lowest flow rates studied (50 ml/kg/min, in, and 10 ml/kg/min, it) produced Pa O 2 capable of maintaining 97% hemoglobin saturation, which should be adequate for most clinical situations. Arterial blood gas analysis and FI O 2 measurements are necessary to accurately guide oxygen flow adjustments to achieve the desired Pa O 2 and to prevent oxygen toxicity produced by excessive FI O 2 .

Free access
in American Journal of Veterinary Research

SUMMARY

Ten coxofcmoral joints from 5 dog cadavers were used to study the effect of coxofcmoral positioning on passive hip laxity. A material test system was used to measure lateral translation when force was between 20 N of compression and 40 N of distraction. Using the orthogonal coordinate system imposed in this study, neutral position was empirically defined at 15° of extension and 10° of abduction, relative to the plane of the pelvis, and no internal or external rotation of the femur. The hips were mounted in a custom-designed jig that allowed 1 rotational degree of freedom (ie, either flexion extension, adduction/ abduction, or internal/external rotation), while holding the other 2 constant. Lateral translation of the hips was tested at 10° intervals from 30° of flexion to 70° of extension, 40° of adduction to 60° of abduction, and 30° of internal rotation to 40° of external rotation. Lateral displacement was maximal at 10° of extension, 20° of abduction, and 10° of external rotation, approximating the neutral coxofcmoral position during stance. As the hips were rotated into extreme positions, the amount of lateral displacement occurring with the same applied load decreased significantly to 32.0 to 65.3% of the maximal displacement. Determining the position of the hip associated with maximal passive laxity in vitro is essential to the design of a precise and accurate clinical stress-radiographic method to quantitate joint laxity in dogs. Our results confirm earlier work that passive hip joint laxity is at a maximum with the hip approximately in a neutral weight-bearing position.

Free access
in American Journal of Veterinary Research

Summary:

The effects of propofol on anesthetic induction were evaluated in 40 dogs anesthetized with isoflurane. Propofol is a rapidly acting, nonbarbiturate drug that induces anesthesia of ultrashort duration with iv administration. Four preanesthetic regimens were used: anesthesia without preanesthetic drugs; or with preanesthetic administration of acepromazine (0.1 mg/kg of body weight, im), diazepam (0.2 mg/kg, iv), or acepromazine (0.02 mg/kg) and butorphanol (0.4 mg/kg) im. Heart rate, systolic arterial blood pressure (sap), respiration, quality of induction and recovery, and adverse effects were recorded. Intravenous propofol administration induced a variable period of apnea in 34 of 40 dogs. Cyanosis (in 2 dogs) and signs of pain on injection (in 3 dogs) were infrequently observed during induction. One dog developed ventricular premature depolarizations after propofol administration. Venous CO2 tension increased and pH decreased immediately after propofol administration, regardless of preanesthetic regimen. The sap significantly (P < 0.05) decreased after propofol administration in dogs treated with acepromazine (sap, 178 mm of Hg before vs 128 mm of Hg after propofol) and with acepromazine/butorphanol (sap, 184 mm of Hg before vs 98 mm of Hg after propofol). When used for induction, propofol induces anesthetic-related adverse effects, some of which can be minimized by preanesthetic medication. Recovery characteristics varied with preanesthetic medication, independent of propofol administration.

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To develop and compare 3 techniques for retrobulbar injection of local anesthetic agents for ocular surgery and analgesia in dogs.

Design—Prospective study.

Animals—17 dogs (including 9 cadavers).

Procedures—Inferior-temporal palpebral (ITP), perimandibular, and combined superior-inferior peribulbar injection techniques were compared by assessing the distribution of latex after injection into the orbits of 5 canine cadavers; magnetic resonance imaging (MRI) evaluation of the distribution of contrast agent after injection in the retrobulbar space of 4 canine cadavers; and assessment of the efficacy and MRI evaluation of the anatomic distribution of injections of a lidocainecontrast agent mixture in 4 anesthetized, nonrecovery dogs. By use of the preferred technique (ITP), the ocular effects of lidocaine anesthesia were evaluated in 4 dogs; during a 2-week period after treatment, dogs underwent ophthalmic examination, Schirmer tear testing (STT), intraocular pressure (IOP) measurement, and Cochet–Bonnet esthesiometry.

Results—Of the 3 techniques, the ITP technique was the preferred method for retrobulbar administration of anesthetic agent in dogs because it was efficacious (pupil dilation and central rotation of the globe achieved in all eyes), easiest to perform, and provided thorough coverage of the intraconal retrobulbar space without complication. During the 2-week follow-up period, the ITP injection did not significantly affect STT, IOP, or Cochet-Bonnet esthesiometry values in dogs.

Conclusions and Clinical Relevance—In dogs, retrobulbar administration of anesthetic agents via the ITP technique is a potential alternative to systemic administration of neuromuscular blocking agents for ophthalmic surgery and provides the additional benefit of local ocular analgesia.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine whether kinematic changes induced by heel pressure in horses differ from those induced by toe pressure.

Animals—10 adult Quarter Horses.

Procedure—A shoe that applied pressure on the cuneus ungulae (frog) or on the toe was used. Kinematic analyses were performed before and after 2 levels of frog pressure and after 1 level of toe pressure. Values for stride displacement and time and joint angles were determined from horses trotting on a treadmill.

Results—The first level of frog pressure caused decreases in metacarpophalangeal (fetlock) joint extension during stance and increases in head vertical movement and asymmetry. The second level of frog pressure caused these changes but also caused decreases in stride duration and carpal joint extension during stance as well as increases in relative stance duration. Toe pressure caused changes in these same variables but also caused maximum extension of the fetlock joint to occur before midstance, maximum hoof height to be closer to midswing, and forelimb protraction to increase.

Conclusion and Clinical Relevance—Decreased fetlock joint extension during stance and increased head vertical movement and asymmetry are sensitive indicators of forelimb lameness. Decreased stride duration, increased relative stance duration, and decreased carpal joint extension during stance are general but insensitive indicators of forelimb lameness. Increased forelimb protraction, hoof flight pattern with maximum hoof height near midswing, and maximum fetlock joint extension in cranial stance may be specific indicators of lameness in the toe region. Observation of forelimb movement may enable clinicians to differentiate lameness of the heel from lameness of the toe. (Am J Vet Res 2000;61:612-619)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To investigate the effects of feeding cereal-based diets that are naturally contaminated with Fusarium mycotoxins to dogs and assess the efficacy of a polymeric glucomannan mycotoxin adsorbent (GMA) in prevention of Fusarium mycotoxicosis.

Animals—12 mature female Beagles.

Procedures—Dogs received each of 3 cereal-based diets for 14 days. One diet was uncontaminated (control diet), and the other 2 contained contaminated grains; one of the contaminated diets also contained 0.2% GMA. Contaminants included deoxynivalenol, 15-acetyl deoxynivalenol, zearalenone, and fusaric acid. Food intake and nutrient digestibility, body weight, blood pressure, heart rate, and clinicopathologic variables of the dogs were assessed at intervals during the feeding periods.

Results—Food intake and body weight of dogs fed the contaminated diet without GMA were significantly decreased, compared with effects of the control diet. Reductions in blood pressure; heart rate; serum concentrations of total protein, globulin, and fibrinogen; and serum activities of alkaline phosphatase and amylase as well as increases in blood monocyte count and mean corpuscular volume were detected. Consumption of GMA did not ameliorate the effects of the Fusarium mycotoxins. For the GMA-contaminated diet, digestibility of carbohydrate, protein, and lipid was significantly higher than that associated with the control diet, possibly because of physiologic adaptation of the recipient dogs to reduced food intake.

Conclusions and Clinical Relevance—Results indicated that consumption of grains naturally contaminated with Fusarium mycotoxins can adversely affect dogs' feeding behaviors and metabolism. As a food additive, GMA was not effective in prevention of Fusarium mycotoxicosis in dogs.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To compare hydromorphone with oxymorphone, with or without acepromazine, for preanesthetic sedation in dogs and assess changes in plasma concentration of histamine after drug administration.

Design—Randomized clinical study.

Animals—10 healthy mixed-breed dogs.

Procedure—Dogs were treated IM with hydromorphone (group H), oxymorphone (group O), hydromorphone with acepromazine (group H/A), or oxymorphone with acepromazine (group O/A). Sedation score, heart rate, respiratory rate, systolic blood pressure, and oxygen saturation were recorded at baseline immediately after drug administration (T0) and every 5 minutes for 25 minutes (T25). Plasma histamine concentration was measured at baseline and T25.

Results—Sedation was similar between groups H and O at all times. Sedation was significantly greater for groups H/A and O/A from T10 to T25, compared with other groups. Systolic blood pressure was significantly reduced at T25 in group H/A, compared with group H, and in group O/A, compared with group O. Prevalence of panting at T25 was 50% for groups H and O, compared with 20% for group H/A and 30% for group O/A. By T25, heart rate was significantly lower in all groups. Oxygen saturation was unaffected by treatment. Mean ± SD plasma histamine concentration was 1.72 ± 2.69 ng/ml at baseline and 1.13 ± 1.18 ng/ml at T25. There was no significant change in plasma histamine concentration in any group.

Conclusions and Clinical Relevance—Hydromorphone is comparable to oxymorphone for preanesthetic sedation in dogs. Sedation is enhanced by acepromazine. Neither hydromorphone nor oxymorphone caused an increase in plasma histamine concentration. (J Am Vet Med Assoc 2001;218:1101–1105)

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine whether bulk-tank standard plate counts or plate loop counts and bulk-tank somatic cell counts (SCC) were associated with detection of violative antimicrobial residues in milk from dairy cattle.

Design—Longitudinal study.

Procedure—Information for 1994 through 1997 was obtained from a large milk marketing cooperative that operated in multiple states throughout the northeastern and midwestern United States (16,831 herd-years of information from 6,546 farms) and from the Ohio Department of Agriculture Grade-A Milk Certification Program (12,042 herd-years of information from 4,022 farms). Data were analyzed by use of multivariate logistic regression.

Results—For both data sets, odds that a violative antibiotic residue would be detected increased as mean SCC for the herd-year increased. Standard plate counts and plate loop counts were not associated with odds that a violative antibiotic residue would be detected.

Conclusions and Clinical Relevance—Results of this study suggested that the odds that a violative antibiotic residue would be found in bulk-tank milk increased as mean SCC for the herd-year increased. This suggests that management practices that would be expected to influence SCC may also influence the risk of antibiotic residue violations. (J Am Vet Med Assoc 2000;217:541–545)

Full access
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association