Survival and complications after large colon resection and end-to-end anastomosis for strangulating large colon volvulus in seventy-three horses.

OBJECTIVE: To report complications and survival after large colon resection and end-to-end anastomosis in horses with strangulating large colon volvulus. STUDY DESIGN: Retrospective case series. ANIMALS: Horses (n=73) with strangulating large colon volvulus. METHODS: Records (January 1995 to December 2005) of horses that had large colon resection and anastomosis for strangulating large colon volvulus were reviewed for complications. Follow-up data were obtained by telephone questionnaire at least 1 year postoperatively. Cox proportional hazards model was used for multivariate association with survival time. Variables included admission date, age, temperature, heart rate, packed cell volume, total plasma protein concentration, white blood cell count, breed, and sex. Significance was set at P<.05. RESULTS: The most common postoperative complication was diarrhea. None of the 9 variables of interest were significant for survival. Short-term survival rate (to discharge) was 74%. Overall survival rates at 1, 2, and 3 years postoperatively were 67.8%, 66.0%, and 63.5%, respectively. Four horses died of colic in the first year after surgery. All horses surviving long-term (>1 year) returned to their intended use (37 brood mares, 2 racehorses, and 1 show horse) with no chronic problems related to the surgical procedure. CONCLUSION: None of the variables examined were associated with survival. Outcomes were similar to other large studies of surgical colic in the horse. Self-limiting diarrhea is common after large colon resection and the prognosis for survival after hospital discharge is favorable. CLINICAL RELEVANCE: Horses that survive the early postoperative period and are discharged after large colon resection and anastomosis have a good chance for long-term survival with minimal negative impact on quality of life and use.

Electronic configuration assignment and the importance of low-lying excited states in high-spin imidazole-ligated iron(II) porphyrinates.

The synthesis and characterization of six new high-spin deoxymyoglobin models (imidazole(tetraarylporphyrinato)iron(II)) are described. These have been intensively studied by temperature-dependent Mossbauer spectroscopy from 295 to 4.2 K. All complexes show a strong temperature dependence for the quadrupole splitting consistent with low-lying excited states of the same or lower multiplicity. An analysis of the data obtained in applied magnetic fields leads to the assignment of the sign of the quadrupole splitting. All model compounds as well as those of deoxymyoglobin and deoxyhemoglobin, previously studied, have a negative sign for the quadrupole splitting. Although not previously predicted, this experimental observation leads to the assignment of the ground-state electronic configuration for all high-spin imidazole-ligated iron(II) porphyrinates as (d(xz)())(2)(d(yz)())(1)(d(xy)())(1)(d(z)()()2)(1)(d(x)()()2(-)(y)()()2)(1). This is a distinctly different ground-state electronic configuration from other high-spin iron(II) porphyrinates; differences in structural details for the two classes of high-spin complexes are also discussed. The apparent anomaly of differing signs for the zero-field splitting constant between previously studied model complexes and the heme proteins is addressed; the difference appears to result from the fact that the assumptions used in the spin Hamiltonian approach that has been applied to these complexes are not adequately satisfied. Structures of four of the new five-coordinate species have been determined. Core conformations in these derivatives show variation, but these and previously studied compounds reveal a limited number of conformational patterns. The bond lengths and other geometrical parameters such as porphyrin core size and iron out-of-plane displacement support a high-spin state assignment for the iron(II).