Immediate postoperative 5-FU does not decrease colonic anastomotic strength

Hyperbaric oxygen therapy and mechanical resistence of the colonics anastomosis in rats with peritonitis

PURPOSE

To analyze the effects of hyperbaric oxygen therapy (HBO) on the mechanical resistance of anastomosis performed in rats' distal colon presenting peritonitis induced by ligature and cecal punction using the Total Energy Rupture biomechanical test (ETR).

METHODS

It was used 45 rats divided into three groups of 15 animals each. In Control Group (CG), it was performed anastomosis in distal colon without peritonitis. In Peritonitis Group (PG), it was performed anastomosis six hours after the induction of peritonitis by ligature and cecal punction. In Hyperbaric Chamber Group (HCG), it was performed six hours after the induction of peritonitis by ligature and cecal punction. The animals on CG and PG were kept at place air while the animals on HCG were placed on an experimental hyperbaric chamber in order to inhale oxygen at 100%, two absolute atmospheres, for 120 minutes, for four consecutive days. Euthanasia took place on the fifth day of the experiment. All the animals underwent to Total Energy Rupture Biomechanical Resistance test (ETR). Total Energy Rupture was defined as the necessary internal energy stored up to promote the colon rupture after an external traction force imposition.

RESULTS

The Peritonitis Group presents smaller average ETR than Control Group. There was no statistical difference between Peritonitis Group and Hyberbaric Chamber Group.

CONCLUSION

Hyperbaric oxygen therapy did not alter the mechanical resistance of anastomosis performed in distal colon of rats under the presence of peritonitis induced by ligature and cecal puncture.

Comparative study of the hyperbaric hyperoxygenation in ischemic colonic loops in rats

PURPOSE: To analyze and to evaluate the effect of the hyperbaric hyperoxygenation in the mechanical resistance of ischemic colon of rats. METHODS: Eighty rats, distributed in four groups of 20 animals in each one, were used. In group 1 (G1), the control group, ischemia was not caused. Group 2 was submitted to the lesser degree of ischemia. Group 3 was submitted to the intermediate degree of ischemia. In group 4, a bigger degree of intestinal ischemia was provoked. Each group was divided in two sub-groups of ten animals each: with hyperbaric chamber (CC) and without hyperbaric chamber (SC). The animals of the four CC subgroups were placed in an experimental hyperbaric chamber in order to inhale oxygen at 100%, at two Absolute Atmospheres, for 120 minutes, for a four-day consecutive period. The animals of the four SC subgroups were kept in environment air during the five days of the experiment. All animals have been submitted to the mechanical study of the intestinal loop by the pressure test of the rupture by liquid distension. The euthanasia occurred in the fifth post-operative day. RESULTS: Considering the ischemia factor, the four groups were different among them (p=0.0001). There was no statistical difference between subgroups CC and SC (p=0.3461). CONCLUSION: The hyperbaric oxygen-therapy did not present improvement on the induced ischemia in rats upright colic loop.

Successful colonoscopic decompression of colon after development of an early postoperative obstruction at the stapled anastomosis after an anterior colectomy and early chemotherapy: a case report

A case report describing the successful colonoscopic decompression and catheter drainage of an early postoperative large bowel obstruction caused by swelling at the stapled anastomosis after the initiation of chemotherapy. Our case illustrates that colonoscopy can be successful in managing early postoperative bowel obstruction secondary to swelling at the stapled colonic anastomosis.

Anastomotic disruption after large bowel resection

Anastomotic disruption is a feared and serious complication of colon surgery. Decades of research have identified factors favoring successful healing of anastomoses as well as risk factors for anastomotic disruption. However, some factors, such as the role of mechanical bowel preparation, remain controversial. Despite proper caution and excellent surgical technique, some anastomotic leaks are inevitable. The rapid identification of anastomotic leaks and the timely treatment in these cases are paramount.

Estudo comparativo da hiperoxigenação hiperbárica em alças cólicas isquêmicas em ratos

OBJETIVO: Analisar e avaliar os efeitos da hiperoxigenação hiperbárica na resistência mecânica do cólon isquêmico de ratos. MÉTODOS: Foram utilizados 80 ratos distribuídos em quatro grupos de 20 animais. No grupo 1, grupo controle, não se provocou isquemia. O grupo 2 foi submetido ao grau menor de isquemia. O grupo 3 foi submetido ao grau intermediário de isquemia. No grupo 4, provocou-se grau maior de isquemia intestinal. Cada grupo foi dividido em dois subgrupos de dez animais cada: com câmara hiperbárica (CC) e sem câmara hiperbárica (SC). Os animais dos quatro subgrupos CC foram colocados em uma câmara hiperbárica experimental para inalarem oxigênio a 100%, a duas atmosferas absolutas, durante 120 minutos, por quatro dias consecutivos. Os animais dos quatro subgrupos SC foram mantidos somente em ar ambiente. Todos animais foram submetidos ao estudo mecânico da alça intestinal pelo teste de pressão de ruptura pela distensão por líquido. A eutanásia ocorreu no quinto dia pós-operatório. RESULTADOS: Os quatro grupos são diferentes entre si considerando o fator isquemia (p= 0,0001). Não houve diferença estatística entre os subgrupos CC e SC (p= 0,3461). CONCLUSÃO: A oxigenoterapia hiperbárica não apresentou melhora sobre a isquemia induzida em alça cólica íntegra de ratos.

Expression and function of inducible nitric oxide synthase during rat colon anastomotic healing

Nitric oxide plays a significant but incompletely understood role in fibroblast function and cutaneous wound collagen synthesis; however, the participation of inducible nitric oxide synthase (iNOS) in gastrointestinal anastomotic healing has not been studied. Male Sprague-Dawley rats underwent single-layer left colonic anastomosis. Animals were killed at 24-hour intervals postoperatively and the anastomosis was excised. Parallel uninjured colon tissue samples were also analyzed. Reverse transcriptase-polymerase chain reaction confirmed the absence of iNOS messenger RNA in control colon and expression of the gene in anastomotic tissue on all study days. Northern hybridization demonstrated maximal iNOS messenger RNA transcription on day 1 with decreased levels on days 3 and 5. iNOS enzyme activity, measured biochemically by the conversion of [(3) H-arginine to [(3) H]-citrulline ex vivo, was also maximal on day 1 (7.35 +/- 1.34 pmol/mg protein/min [+/- standard error of the mean], n = 10) and decreased on days 3 (4.37 +/- 2.32 pmol/mg protein/min; n = 6) and 5 (2.80 +/- 0.92 pmol/mg protein/min; n = 6). Immunohistochemical staining demonstrated that (1) iNOS expression is confined to a discrete cell population in the region of the anastomosis containing inflammatory cells; (2) those cells assume a highly conserved position on the luminal edge of the proliferating scar; and (3) the iNOS-expressing cells are present throughout the fibroplastic phase of healing. To functionally assess the role of iNOS in colonic healing, rats were treated with a continuous intravenous infusion of S-methylisothiourea (a selective inhibitor of iNOS) at a dosage of 200 mg/kg/day for 5 days after anastomosis. There was a significantly reduced anastomotic bursting pressure in rats treated with the inhibitor as compared to rats treated with intravenous normal saline solution (108.4 +/- 13.2 mm Hg vs. 148.4 +/- 10.3 mm Hg; P <0.05). These results suggest that iNOS gene expression is induced during colonic anastomotic healing, that it is present through all phases of healing but is maximal through the inflammatory phase, and that iNOS activity is required for optimal anastomotic healing.