Effects of a curricular revision on learner outcomes in veterinary clinical pathology.

A mixed-methods evaluation was conducted to study learner attitudes and knowledge about clinical pathology across a curricular change that instituted a stand-alone clinical pathology course in place of content within a previously integrated pathology course structure. Groups of pre- and post-change students were assessed three times across the two semesters leading up to graduation. At each time, rank-ordered and open-ended response items probed attitudes, and multiple-choice items assessed knowledge. Data about student clinical pathology performance were also collected from clinical pathology instructors and supervising clinicians. Student rank-ordered items were evaluated by factor analysis; resulting factor-scale scores, multiple-choice scores, and rank responses from study cohorts were statistically assessed between groups and within each group over time. Intraclass correlations were calculated for the coding of student open-ended responses, and all coded responses were compared among groups. Analysis revealed that students in the revised curriculum had greater satisfaction with their training and greater confidence in data interpretation compared to students without exposure to an independent clinical pathology course. Although differences in knowledge of clinical pathology were not detected, it was also apparent that the independent clinical pathology course filled a student-perceived curricular need without raising criticisms related to diminished integration with anatomic pathology. Secondary study outcomes included formative feedback for course improvement, evidence of clerkship efficacy, and baseline data for further studies.

An integrative and case-based approach to the teaching of general and systemic pathology.

Since 1993, the pre-clinical phase of the professional (DVM) curriculum at Michigan State University College of Veterinary Medicine has included two pathology courses in which both anatomic and clinical pathologists collaborate to teach concepts in general and systemic pathology. Topics such as inflammation, circulatory disturbances, and neoplasia are taught in this collaborative manner in the year 1 General Pathology course, and pathology of the digestive system (including liver and pancreas), urinary system, and lymphoid system are "team-taught" in the year 2 Clinical and Systemic Pathology course. We feel that this approach gives students an appreciation of the whole-body dynamics of a disease process as it occurs in bone marrow, peripheral blood, body fluids, and tissues and that it leads to a deep understanding of pathologic processes. In addition, the use of "active learning" instructional strategies grounded in case discussions further enhances students' understanding of important concepts by demonstration of practical applications and serves to generate strong interest in learning the subject matter. Integration of concepts of pathology with those taught concurrently in other courses, such as those in physiology and microbiology, is also an important component of pathology instruction in the pre-clinical curriculum.

Diarrhea and hyperammonemia in a horse with progressive neurologic signs.

A 2-year-old, Quarter Horse filly was referred to Michigan State University, Veterinary Teaching Hospital with a 2-3 day history of depression and partial anorexia progressing to severe, watery diarrhea with severe neurologic abnormalities, including repetitive muscle fasciculations, muscle stiffening, and collapse. Laboratory findings included severe polycythemia, neutropenia, metabolic acidosis, and electrolyte and fluid loss, consistent with watery diarrhea and endotoxic shock. Increased creatine kinase and aspartate transaminase activities were consistent with recent transport and the muscle abnormalities. Severe hyperammonemia (1369.0 micromol/L; control value, 15.3 micromol/L) was found, without other substantial laboratory evidence of hepatic dysfunction. The horse was euthanized because of poor prognosis and rapid clinical deterioration. Necropsy findings were unremarkable with the exception of severe diffuse colitis. Culture of colonic contents recovered >1000 colony-forming units of Clostridium perfringens. Based on these findings, marked hyperammonemia in this filly was attributed to changes in colonic flora leading to increased bacterial production of ammonia that was readily absorbed through the inflamed bowel wall, exceeding the hepatic capacity for deamination. Intestinal bacteria as a source of hyperammonemia in the absence of hepatic disease has been linked rarely to positive culture results for clostridial organisms.

Autosomal recessive severe combined immunodeficiency of Jack Russell terriers.

Because of unexplained mortality among 33 sibling offspring of a single pair of dogs, a family of Jack Russell Terriers was investigated. Twelve pups, 5 male and 7 female, died between 8 and 14 weeks of age. Six of those animals died in the field within 50 hours following vaccination with modified live vaccines. Subsequent histopathologic examination revealed the absence of splenic white pulp in 4 dogs and hepatic inclusions diagnostic for adenoviral infection in 2 dogs. Two additional litters yielded 2 pups with the same splenic and hepatic lesions. These observations led to a detailed study of 7 siblings whelped specifically for this investigation. Four of these 7 siblings had a profound lymphopenia and a decrease in serum immunoglobulins. Six of these dogs were necropsied at 7 weeks of age, and 4 of them had marked hypoplasia of all lymphoid tissue. The affected pups had an 86% decrease in mean thymic weight, with poor corticomedullary differentiation, and very few CD3-positive (T cell) thymocytes were detected immunohistochemically. However, the affected thymic tissue stained intensely with a immunochemical stain for cytokeratin. The other affected lymphoid tissues were identified histologically only by stromal architectural characteristics. Lymph nodes lacked both CD3 and CD79a (B cell) positive cells. The analyzed breeding data were consistent with an autosomal recessive mode of inheritance. This canine severe combined immunodeficiency has immunologic and pathologic features similar to those observed in immunodeficient C.B-17 mice and Arabian horses.