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in Journal of the American Veterinary Medical Association

SUMMARY

Corticocancellous bone graft was obtained from the caudoventral portion of the mandible of 8 dogs. The recipient site was an alveolar jugal and alveolar defect from vital root amputation of the mesiobuccal root of the maxillary fourth premolar. Anatomic observations of 20 canine cadavers indicated that guidelines for harvesting bone from the caudoventral portion of the mandible of dogs were the mesial aspect of the masseteric fossa, the distal aspect of the roots of the first mandibular molar, and the ventral aspect of the mandibular canal. The mean weight of corticocancellous bone harvested was 0.4 ± 0.1 g. Harvested corticocancellous bone was adequate to fill recipient sites measuring a mean volume of 105.0 ± 28.5 mm3. Histologic evaluation of the recipient site revealed progressive osseous integration of the bone-graft site during a mean follow-up period of 3.5 ± 1.9 months. There was normal bone healing of the donor site without adverse effects on the mandibular molars or neurovascular structures of the mandibular canal. Vital amputation sites receiving silver amalgam had evidence of plasmacytic/lymphocytic inflammation associated with residual silver amalgam in the bone-graft area. The caudoventral portion of the mandible may be used as a donor site for autogenous corticocancellous bone in periodontal surgery of dogs.

Free access
in American Journal of Veterinary Research

Abstract

Objectives

To determine the sequence of cardiovascular and blood gas changes induced by ingestion of fumonisin-containing culture material in swine and to examine the temporal relationship of these changes to plasma sphinganine and sphingosine concentrations.

Animals

12 healthy castrated pigs (38 to 50 kg).

Procedure

Pigs were instrumented to permit cardiovascular monitoring and collection of blood samples. Baseline values were obtained, and pigs were randomly assigned to 1 of 2 groups. Control pigs (n = 6) were fed a standard grower diet, whereas culture material that contained 20 mg of fumonisin B1/kg of body weight was added to the feed of treated pigs (n = 6) each day. Hemodynamic data, results of arterial and mixed venous blood gas analyses, and plasma sphinganine and sphingosine concentrations were recorded every 12 hours until treated pigs were euthanatized because of impending death from pulmonary edema.

Results

Sphinganine and sphingosine concentrations were increased in plasma of treated pigs within 24 hours of initial fumonisin exposure and continued to increase dramatically until euthanasia. Fumonisin-treated pigs had increased respiratory rate, mean pulmonary artery pressure, and pulmonary artery wedge pressure, along with decreased heart rate and cardiac output in the 12-hour period before euthanasia. Fumonisin-treated pigs also had systemic arterial hypotension, arterial and mixed venous hypoxemia, metabolic acidosis, decreased oxygen delivery, and increased oxygen consumption immediately before euthanasia.

Conclusions and Clinical Relevance

Fumonisin-induced pulmonary edema in swine is probably caused by acute left-sided heart failure. Onset of hemodynamic changes was associated with plasma sphinganine concentration ≥ 2.2 μM/L and plasma sphingosine concentration ≥ 1 µM/L (Am J Vet Res 1999;60:1292–1300)

Free access
in American Journal of Veterinary Research

Abstract

Objective—To determine whether cardiovascular dysfunction is evident in horses with leukoencephalomalacia experimentally induced by administration of fumonisin B1.

Animals—11 healthy horses of various breeds (body weight, 252 to 367 kg).

Procedure—Horses were randomly assigned to 3 groups and administered fumonisin B1 daily. Horses received IV injections of 0 (control horses; n = 4), 0.01 (3), or 0.20 mg (4) of fumonisin B1/kg for 7 to 28 days. Horses were examined daily for evidence of neurologic disease. When neurologic signs consistent with leukoencephalomalacia were evident, horses were anesthetized, and catheters were inserted for evaluation of the cardiovascular system. After recovery from anesthesia, hemodynamic measurements were obtained.

Results—Fumonisin-treated horses with clinical signs of neurologic disease had evidence of cardiovascular dysfunction manifested as decreases in heart rate, cardiac output, right ventricular contractility (assessed by measuring the maximal rate of change of right ventricular pressure), coccygeal artery pulse pressure, and pH and base excess in venous blood as well as increases in systemic vascular resistance, compared with values for control horses. Fumonisin-treated horses with and without clinical signs of neurologic disease also had higher serum and right ventricular sphinganine and sphingosine concentrations than control horses.

Conclusions and Clinical Relevance—An association was detected among fumonisin-induced neurologic disease, increased serum and myocardial sphinganine and sphingosine concentrations, and decreased cardiovascular function in horses. Fumonisin-induced decreases in cardiovascular function may contribute to the pathophysiologic development of leukoencephalomalacia in horses. (Am J Vet Res 2002;63:538–545).

Full access
in American Journal of Veterinary Research

Abstract

Objective

To determine the effects of autologous fibrinogen (AF) and absorbable barrier membrane (ABM) on periodontal healing of canine experimental grade-III furcation defects.

Animals

18 conditioned, laboratory-source, adult Beagles.

Procedure

Defects were developed bilaterally at the second and fourth premolars and maintained for 12 weeks. Defects were treated with AF, ABM, AF and ABM, or debridement. Digital subtraction radiography, histologic evaluation, and histomorphometric analysis of defect healing was done at 1, 3, and 6 months after treatment to determine percentage increases in bone volume, height, area, and length of periodontal regeneration along the perimeter of the defect.

Results

Comparison of defects at post-treatment intervals indicated significantly greater healing of debridement and AF-treated defects, compared with ABM-treated defects at 3 months; however, by 6 months, there were no significant differences in defect healing for all histomorphometric variables. Defects treated with ABM were associated with significantly less root ankylosis than other treatments. Defects treated with debridement had significantly greater increases in bone volume at 6 months after treatment, compared with groups treated with ABM. There was a significant correlation between regenerated bone area, bone volume, and periodontal regeneration for all treatments at 3 and 6 months after treatment.

Conclusion and Clinical Relevance

Use of AF and ABM did not enhance the amount of periodontal healing, compared with debridement only. The ABM-treated defects were essentially devoid of root ankylosis. Grade-III furcation defects may respond equally well to conservative periodontal surgery or guided tissue regenerative techniques. The prevention of root ankylosis is a substantial benefit favoring this latter method of treatment. (Am J Vet Res 1998;59:1329-1338)

Free access
in American Journal of Veterinary Research

Summary

Bilateral midbody hemimandibular osteotomies were performed between premolars 3 and 4 in 18 adult dogs. Hemimandibles were repaired by use of monocortically applied bone plates (n = 6), an interdental fixator composed of an Erich arch bar and acrylic (n = 6), or a type I external skeletal fixator (n = 6). At the immediate postoperative evaluation, hemimandibles stabilized with interdental fixators had an osteotomy gap distance (mean ± SEM, 1.6 ± 0.2 mm) that was significantly (P < 0.05) greater than for hemimandibles stabilized with external skeletal fixators (1.2 ± 0.3 mm). Osteotomy gap distance of hemimandibles stabilized with external skeletal fixators (1.5 ± 0.2 mm) was significantly (P < 0.05) greater at weeks 4 (1.1 ± 0.2 mm) and 8 (0.8 ± 0.3 mm) after surgery than the osteotomy gap distance of hemimandibles stabilized by application of bone plates. By week 16, significant differences in osteotomy gap distance were not detected between groups. Immediately after surgery, mandibular alignment measurements were not significantly different for dogs with bone plates (0.3 ± 0.1 mm), interdental fixators (0.3 ± 0.1 mm), and external skeletal fixators (0.9 ± 0.5 mm). Mandibular alignment scores were not significantly different between treatment groups during the remaining postoperative period. Occlusal measurements were not significantly different between evaluations performed before surgery and 16 weeks after surgery, regardless of treatment group. Radiographic evidence of healing in hemimandibles stabilized with external skeletal fixators was significantly (P < 0.05) less at 4 and 8 weeks, compared with hemimandibles stabilized with bone plates and interdental fixators; however, radiographic evidence of bone healing was not significantly different between fixation groups at 16 weeks. Radiographic evidence of implant loosening was seen in 1 of 12 (8%) hemimandibles receiving bone plates, 1 of 12 (8%) hemimandibles receiving interdental fixators, and 4 of 12 (33%) hemimandibles receiving external skeletal fixators. Periosteotomy callus was radiographically evident in 11 of 18 (61%) hemimandibles at 4 and 8 weeks only, but significant differences in periosteotomy callus surface area were not detected between groups. Of 24 hemimandibles stabilized with interdental and external skeletal fixators, 22 (92%) had callus formation that progressively matured into trabecular bone by 16 weeks. At 4 weeks, bone healing characterization scores of hemimandibles stabilized with bone plates were significantly (P < 0.05) less than (ie, had greater stability) bone healing characterization scores of hemimandibles stabilized with interdental and external skeletal fixators, but at 8 and 16 weeks, bone healing characterization scores between treatment groups were not significantly different. Histopathologic or radiographic evaluation did not reveal evidence of pulp disease or pathologic changes of teeth, which would have been associated with root resection at the osteotomy site, application of acrylic to the crown surface, or placement of external fixator pins and cortical screws. On the basis of the fact that the dogs appeared clinically normal and were able to masticate, analgesics were discontinued by 24 hours after surgery. Analysis of data indicated that an interdental fixator composed of an Erich arch bar and acrylic may be a viable method for fracture repair of mandibles.

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in Journal of the American Veterinary Medical Association