Animal-related injury in an urban New Zealand population.

The contribution of animals to injury in urban populations is not well described. We reviewed our trauma admissions for animal-related injury to identify animals involved, risk factors and patterns of injury. Eight thousand nine hundred and fifty-four patients were admitted for trauma during the study period. One hundred and sixty-seven injuries were due to animals (1.9%). Horses were involved in 86% and dogs in 10% of injuries. Most horse riders were injured in falls. Factors associated with increased risk included being young, female and riding for leisure. Body regions most commonly injured were the head and both upper and lower extremities. Patterns of injury were identified. Horse-related injury is a significant source of traumatic injury in an identifiable at-risk subgroup of our urban population. High rates of head injury and low rates of helmet use suggest a more effective strategy to encourage use of protective headgear is needed. Further efforts aimed at injury prevention must include an improvement in skill and knowledge of horsemanship, particularly in the at-risk group of young female amateur riders. Mechanistic patterns of injury and body-region markers identified in this study may assist early recognition of severe and occult injuries in these patients.

The impact of intestinal ischaemia-reperfusion on caerulein-induced oedematous experimental pancreatitis.

BACKGROUND: Intestinal ischaemia is a feature of severe acute pancreatitis. It is not known whether intestinal ischaemia and reperfusion contributes to the progression from mild to severe pancreatitis. AIM: The aim of this study was to examine the impact of intestinal ischaemia-reperfusion on caerulein-induced oedematous experimental pancreatitis. METHOD: Male Wistar rats (n = 48) were randomised to 6 experimental groups: controls (CO), saline infusion (S), saline infusion and intestinal ischaemia-reperfusion (SIR), caerulein infusion (C), caerulein and sham operation (CS), and caerulein infusion with intestinal ischaemia reperfusion (CIR). Caerulein was infused over 6 h to induce mild oedematous pancreatitis. Clamping the superior mesenteric artery for 10 min induced mild intestinal ischaemia. The reperfusion time was 24 h. The primary end point was histology of the pancreas at 24 h. RESULTS: There was no significant difference in histologic severity of pancreatitis at 24 h (Kruskal-Wallis, p = 0.37). CONCLUSION: The severity of acute oedematous pancreatitis was not increased by 10 min of intestinal ischaemia followed by 24 h of reperfusion.

Plasma amylin concentration is related to the severity of intestinal ischemic injury in rats.

BACKGROUND: Previous work has demonstrated that intestinal ischemia increases plasma amylin concentration. This study examined the relationship between the degree of intestinal ischemia injury and plasma amylin in an experimental rat model. METHODS: Wistar rats were divided into a control group (n = 6); a sham-operated group (n = 9); and 3 intestinal ischemia-reperfusion groups (n = 8 in each), which underwent clamping of the superior mesenteric artery for either 15, 30, or 45 minutes followed by 15 minutes of reperfusion. Samples were then collected for intestinal histology and measurement of amylin, insulin, and glucose. RESULTS: There was a positive correlation between the histologic score of the intestinal injury and the measured plasma amylin concentration (R = 0.48, P =.007). The median plasma concentration of amylin was 62 pmol/L (range, 42-97 pmol/L) in the 30-minute intestinal ischemia group and 58 pmol/L (42-86 pmol/L) in the 45-minute intestinal ischemia group. Both these groups were increased compared with the sham-operated group (29 pmol/L; range, 22-57 pmol/L; P <.001 and P <.005, respectively) and the control group (28 pmol/L; range, 26-42 pmol/L; P <.001 and P <.0005, respectively). The median plasma concentration of insulin in the 30-minute intestinal ischemia group was 4230 pmol/L (range, 1360-5770 pmol/L), which was increased compared with both the control group (950 pmol/L; range, 550-1510 pmol/L; P <.005) and the sham-operated group (720 pmol/L; range, 280-4180 pmol/L; P<.005). There were no differences between any of the other groups either for glucose, insulin, or amylin. CONCLUSIONS: Plasma amylin concentration is related to the severity of intestinal ischemic injury.

A method using laser Doppler flowmetry to study intestinal and pancreatic perfusion during an acute intestinal ischaemic injury in rats with pancreatitis.

Intestinal ischaemia is implicated in the pathogenesis of severe acute pancreatitis, a disorder characterized by acinar necrosis. To study the relationship between pancreatic and intestinal microvascular perfusion during 40 min of intestinal ischaemia and 30 min of reperfusion in rodents with acute pancreatitis, a model utilizing laser Doppler flowmetry was developed. It is reported here together with practical solutions for (1) a modified method of vessel cannulation; (2) a novel method for the temperature-controlled optical coupling between laser Doppler probes and rodent tissues, and (3) a simple technique of inducing intestinal ischaemia-reperfusion while continuously monitoring the microvascular perfusion in both pancreas and intestine. The utility of the model is demonstrated in a pilot study that showed that the pancreatic perfusion fell acutely to 58% (p = 0.029) of baseline during the intestinal reperfusion phase. This reduced perfusion continued for 30 min despite recovery of both the intestinal perfusion and the mean arterial blood pressure to baseline levels.

Caerulein-induced pancreatitis in Wistar rats.

We describe a refined model of intravenous caerulein-induced pancreatitis by using osmotic infusion pumps in the conscious unrestrained Wistar rat. The volume of caerulein required for the 6-h infusion is loaded into PE-55 catheter tubing attached to an Alzet (Alza Corporation, Palo Alto, CA) implantable osmotic pump that has been primed with saline. The technique has reliably induced mild edematous pancreatitis, which we verified histologically. Our refined model has the advantages of unrestrained animals, reduced animal handling and acclimation, and decreased cost.

Plasma von Willebrand factor and intestinal ischaemia-reperfusion injury in rats.

The purpose of this study was to determine whether plasma von Willebrand factor concentrations are correlated with the degree of intestinal ischaemia-reperfusion injury. Forty-six anaesthetised adult Wistar rats were divided into five groups. The sham-operated group (S, n=10) had laparotomy and isolation of the superior mesenteric artery without clamping. Three ischaemia-reperfusion groups (n=10 in each) had clamping of the superior mesenteric artery for 15, 30, and 45 minutes, respectively, and reperfusion for 15 minutes. A control group (C, n=6) had direct puncture of the heart to sample blood. Mean arterial pressure was measured continuously. Blood was collected at the end of the study to measure von Willebrand factor. The small bowel injury was graded histologically. There was a significant systemic hypotension after declamping in all ischaemia-reperfusion groups, which had a high negative correlation with the histological score (R=-0.46, F=10.1, p<0.003, simple linear regression). Plasma von Willebrand factor was significantly elevated in the three ischaemia-reperfusion groups compared with the control group but not significantly different from the sham-operated group (mean von Willebrand factor concentration (SEM): 156 (29), 283 (29), 295 (25), 381 (44), and 366 (40)% in C, S, ischaemia-reperfusion 15, ischaemia-reperfusion 30, and ischaemia-reperfusion 45 groups, respectively). The concentration of von Willebrand factor was not correlated to the histological score (R=0.22, F=1.83, p<0.2) or the degree of hypotension after the removal of the clamp (R=-0.22, F=1.8, p<0.2, simple linear regression). This study shows that von Willebrand factor concentration does not correlate with the degree of intestinal ischaemia-reperfusion injury. It is unlikely that von Willebrand factor can be used as a predictor of disease severity.

Assessment of proliferative activity in Wilms' tumour.

The proliferative activity in 26 cases of Wilms' tumour was studied by enumeration of silver-staining nucleolar organizer regions (AgNORs) and proliferating cell nuclear antigen (PCNA) staining of the blastemal, epithelial and stromal components of the tumours. The PCNA and AgNOR scores derived from the blastemal (PCNA range 18.9-81.4%, AgNOR range 2.11-4.95) and epithelial (PCNA range 24.1-74.2%, AgNOR range 2.47-4.41) components of the tumours were significantly higher than those of the stromal component (PCNA range 3.4-64.7%, AgNOR range 2.20-4.26). Ten of the patients had died with recurrent or metastatic tumour (mean survival 29 months) while the remaining 16 were disease free (mean follow-up 95 months) at the time of the study. The prognostic significance of PCNA and AgNOR for Wilms' tumour was evaluated by dividing the tumours into groups exhibiting low (PCNA < or = 40 or AgNOR < or = 4) or high (PCNA > 40 or AgNOR > 4) proliferative activity. There was a significant difference in the survival of the two groups for tumours treated with preoperative chemotherapy (PCNA, P = 0.049; AgNOR, P = 0.02), while no significant difference was observed from tumours resected prior to the administration of chemotherapy. The results of this study suggest that assessment of proliferation activity in postchemotherapy Wilm's tumours may be a useful indicator of prognosis.