Biomedical subjects

Bernard Séguin

Publications and source records attributed to Bernard Séguin.

7 recordsLinked to original sources

PubMed2005

Evaluation of the effect of routine histologic processing on the size of skin samples obtained from dogs.

OBJECTIVE: To determine the effects that routine histologic processing has on the dimensions of samples of normal skin of dogs and assess whether the inclusion of a muscle or fascial layer in such samples alters those effects. SAMPLE POPULATION: Skin samples obtained from 6 medium-sized adult dogs with grossly normal skin. PROCEDURE: From each dog, skin samples (with or without underlying fascia or muscle) were obtained from 3 sites bilaterally (6 samples/dog) and processed routinely for histologic evaluation; their dimensions were measured at intervals during the experiment. RESULTS: As a result of processing, skin samples decreased in size (combined percentage change in length and width) and increased in thickness, compared with their original dimensions. Samples without fascia or muscle decreased in size by 21.1% to 32.0% and increased in thickness by 45.1 % to 75.8%. The site of sample origin influenced processing-associated changes in sample size but did not affect the change in thickness. Decreases in dimensions did not vary with inclusion of fascia but did vary with inclusion of muscle. The change in thickness did not vary with inclusion of a layer of fascia or muscle. CONCLUSIONS AND CLINICAL RELEVANCE: Processing of skin samples obtained from dogs for histologic evaluation can cause changes in sample dimensions; samples may decrease in length and width by as much as 32% and increase in thickness by 75.8%, compared with their original dimensions. The presence of muscle in canine skin samples can restrict the amount of shrinkage in length or width associated with processing.

Animals↗

PubMed2002

Feline injection site sarcomas.

Feline injection site sarcomas have mostly been associated with the administration of vaccines. Although the pathogenesis remains largely unknown, it is believed the inflammatory reaction caused by the injection of the compound leads to uncontrolled proliferation of fibroblasts and myofibroblasts that may undergo malignant transformation in a subset of cats. Pretreatment evaluation and proper planning of therapy are essential. Currently, because of the aggressive nature of these tumors, a multimodality treatment approach is recommended.

Animals↗

PubMed2002

Injection site sarcomas in cats.

Feline injection-site sarcomas have mostly been associated with the administration of vaccines. Although the pathogenesis remains largely unknown, it is believed that the inflammatory reaction caused from the injection of the compound leads to uncontrolled proliferation of fibroblasts and myofibroblasts that in a subset of cats undergo malignant transformation. Pretreatment evaluation and proper planning of the therapy are essential. Because of the aggressive nature of these tumors, a multimodality treatment approach is being recommended. A combination of surgery and radiation therapy with or without chemotherapy appears to be providing the best prognosis.

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PubMedDate not supplied

Use of an ipsilateral vascularized ulnar transposition autograft for limb-sparing surgery of the distal radius in dogs: an anatomic and clinical study.

OBJECTIVE: To develop a surgical technique for using the distal aspect of the ulna as a transposition autograft in a distal radial defect and to assess patency of vascular supply and viability of the distal ulna in a heterotopic position. STUDY DESIGN: Cadaveric study and clinical cases. ANIMALS: Twenty-two normal canine thoracic limbs; 3 dogs with distal radial osteosarcoma. METHODS: The arteries and veins of 12 limbs were injected with latex. Barium sulfate suspension was injected into the brachial artery of 10 other limbs after removal of the distal radius only (n = 2), ulna transposition (UT) (n = 6), or no procedure (n = 2). The distal ulna grafts were then harvested and decalcified in formic acid. The grafts were cut into 3-5 mm transverse sections and radiographed with a nonscreen film system to determine filling of intramedullary vessels with barium suspension. UT was performed in 3 dogs with distal radial osteosarcoma. Bone scintigraphy was performed 2-7 days after surgery to assess viability of the transposed ulna graft. RESULTS: Angiography confirmed patency of the caudal interosseous artery in all but 2 limbs in which the UT technique was performed; however, barium-filled vessels were identified in the medullary cavity of all ulnar grafts. Scintigraphy confirmed graft viability in the 3 dogs, all of which had good to excellent limb function. CONCLUSIONS: The distal aspect of the canine ulna can be used as a vascularized transposition autograft to replace distal radial defects, and viability can be maintained. CLINICAL RELEVANCE: The UT technique appears to be an acceptable limb-sparing technique for dogs with tumors of the distal aspect of the radius.

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PubMedDate not supplied

Biomechanical comparison of cortical radial graft versus ulnar transposition graft limb-sparing techniques for the distal radial site in dogs.

OBJECTIVE: To compare the biomechanical properties of radial graft (RG) versus ulnar transposition graft (UTG) limb-sparing techniques in the dog. STUDY DESIGN: Cadaveric study. ANIMALS: Six pairs of normal canine thoracic limbs. METHODS: In each pair of limbs, 1 limb was subjected to the RG technique and the other to the UTG technique. Limbs were tested in axial loading until failure. Modes of failure and biomechanical properties were compared between the 2 groups. Percent coverage of the metacarpal bone by the plate was retrospectively compared between the limbs that failed by fracture of the metacarpal bones and those that did not. RESULTS: RG limbs had significantly greater stiffness, yield load, maximum load, maximum energy, and post-yield energy. All UTG limbs failed by cranial bending of the plate. Half of the RG limbs failed by caudal bending of the plate and half by fracture of the third metacarpal bone at the distal end of the plate. Limbs with <80% plate coverage of the metacarpal bone were significantly more likely to fail by metacarpal fracture. CONCLUSIONS: The RG technique was biomechanically superior to the UTG technique under the conditions studied. At least 80% plate coverage of the metacarpal bone should be achieved. CLINICAL RELEVANCE: Exercise restriction and coaptation bandages should be considered for patients undergoing the UTG technique to minimize potential biomechanical complications.

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PubMedDate not supplied

Tolerance of cutaneous or mucosal flaps placed into a radiation therapy field in dogs.

OBJECTIVE: To determine the clinical outcome and factors affecting cutaneous or mucosal flaps in dogs treated with radiation therapy (RT). STUDY DESIGN: Longitudinal clinical study. ANIMALS: Twenty-six client-owned dogs. METHODS: Dogs entered in the study had a flapping procedure and RT as part of their treatment. The sequence of flapping and RT included: (1) planned preoperative RT, (2) postoperative RT, and (3) flapping as a salvage procedure for management of complications or local tumor recurrence after RT. Flap complications were defined as necrosis, local infection, dehiscence, and ulceration. The risk and severity of flap complication were analyzed independently. RESULTS: Twenty (77%) dogs had a complication; 6 dogs required an additional flapping procedure; and 4 dogs had an unresolved complication. Flapping procedures performed to correct a complication, or failure of RT, had a significantly greater risk for complication; however, postoperative RT decreased the severity of complication. A dose per fraction of 4 Gy compared with 3 Gy was prognostic for increased severity of complications, whereas the head and neck location was prognostic for decreased severity of complication. CONCLUSIONS: Although morbidity was substantial, cutaneous or mucosal flaps were used successfully in an RT field in 85% of the dogs. Flaps that were part of the planned therapy as opposed to those used to correct a complication or failure of RT had a better clinical outcome. CLINICAL RELEVANCE: Cutaneous or mucosal flaps can be part of the treatment of dogs with tumor when adjuvant or neoadjuvant RT is to be used.

Acanthoma↗

PubMedDate not supplied

Recurrence rate, clinical outcome, and cellular proliferation indices as prognostic indicators after incomplete surgical excision of cutaneous grade II mast cell tumors: 28 dogs (1994-2002).

The objectives of this study were to determine local recurrence rate, clinical outcome, and prognostic value of the number of argyrophylic nucleolar organizer regions (AgNORs), presence of proliferating cell nuclear antigen (PCNA), and number of Ki-67-positive nuclei after incomplete surgical excision of canine cutaneous grade II mast cell tumors (MCTs). This retrospective study included 30 MCTs in 28 dogs. Medical records were examined and follow-up information was obtained from owners and referring veterinarians. Only cases in which excision was incomplete and no anvcillary therapy (other than prednisone) for MCT was given were included. Paraffin-embedded tumor tissues were retrieved for AgNORs, PCNA, and Ki-67 staining. Median follow-up time was 811.5 days. Seven (23.3%) tumors recurred locally. Median time to local recurrence was not reached with a mean of 1,713 days. The estimated proportions of tumors that recurred locally at 1, 2, and 5 years were 17.3, 22.1, and 33.3%, respectively. Eleven (39.3%) dogs developed MCTs at other cutaneous locations. Median progression-free survival was 1,044 days. Median overall survival was 1,426 days. The combination of Ki-67 and PCNA scores was prognostic for local recurrence (P = .03) and development of local recurrence was prognostic for decreased overall survival (P = .04). Results suggest that a minority of incompletely excised MCTs recur. Therefore, ancillary local therapies may not always be necessary. However, local recurrence can negatively affect survival of the affected dogs. Cellular proliferation indices may indicate the likelihood of MCT recurrence after incomplete excision.

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