The protective effect of ischemic preconditioning on rat testis

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Introduction of an agent-based multi-scale modular architecture for dynamic knowledge representation of acute inflammation

<p>Abstract</p> <p>Background</p> <p>One of the greatest challenges facing biomedical research is the integration and sharing of vast amounts of information, not only for individual researchers, but also for the community at large. Agent Based Modeling (ABM) can provide a means of addressing this challenge via a unifying translational architecture for dynamic knowledge representation. This paper presents a series of linked ABMs representing multiple levels of biological organization. They are intended to translate the knowledge derived from in vitro models of acute inflammation to clinically relevant phenomenon such as multiple organ failure.</p> <p>Results and Discussion</p> <p>ABM development followed a sequence starting with relatively direct translation from in-vitro derived rules into a cell-as-agent level ABM, leading on to concatenated ABMs into multi-tissue models, eventually resulting in topologically linked aggregate multi-tissue ABMs modeling organ-organ crosstalk. As an underlying design principle organs were considered to be functionally composed of an epithelial surface, which determined organ integrity, and an endothelial/blood interface, representing the reaction surface for the initiation and propagation of inflammation. The development of the epithelial ABM derived from an in-vitro model of gut epithelial permeability is described. Next, the epithelial ABM was concatenated with the endothelial/inflammatory cell ABM to produce an organ model of the gut. This model was validated against in-vivo models of the inflammatory response of the gut to ischemia. Finally, the gut ABM was linked to a similarly constructed pulmonary ABM to simulate the gut-pulmonary axis in the pathogenesis of multiple organ failure. The behavior of this model was validated against in-vivo and clinical observations on the cross-talk between these two organ systems</p> <p>Conclusion</p> <p>A series of ABMs are presented extending from the level of intracellular mechanism to clinically observed behavior in the intensive care setting. The ABMs all utilize cell-level agents that encapsulate specific mechanistic knowledge extracted from in vitro experiments. The execution of the ABMs results in a dynamic representation of the multi-scale conceptual models derived from those experiments. These models represent a qualitative means of integrating basic scientific information on acute inflammation in a multi-scale, modular architecture as a means of conceptual model verification that can potentially be used to concatenate, communicate and advance community-wide knowledge.</p

Comparison of electromagnetic field stimulation on the healing of small and large intestinal anastomoses

Nayci, Ali/0000-0002-0534-1205WOS: 000170453000023PubMed: 11535860PURPOSE: Magnetic fields have been shown to affect biologic processes. Accordingly, an experimental study was designed to investigate the effect of electromagnetic field stimulation on intestinal healing and to compare small and large intestinal anastomoses. METHODS: An ileal or a colonic anastomosis was constructed in rats. Beginning the day after surgery, randomly assigned groups were exposed to sinusoidal electromagnetic field stimulation of 10.76-mT intensity and 50-Hz frequency, with 2-hour-on/10-hour-off cycles. After seven days, intestinal anastomoses were assessed for hydroxyproline content and breaking strength. Statistical comparison between each experimental and control group yielded significance (P g/mg (P = 0.0249) and in colon from 1.526 +/- 0.11 to 1.922 +/- 0.11 mug/mg (P = 0.0135). Breaking strength also increased significantly in ileum from 0.213 +/- 0.01 to 0.255 +/- 0.01 MPa (P = 0.001) and in colon from 0.227 +/- 0.01 to 0.270 +/- 0.01 MPa (P = 0.006). CONCLUSIONS: Electromagnetic field stimulation provided a significant gain in anastomotic healing in both small and large intestine. There were no apparent differences detected between the healing of small and large intestinal anastomoses except for slight differences in the tune sequences of events and magnitude. The study demonstrated a significant increase in both biochemical and mechanical parameters. Additional investigations are needed to determine optimal conditions and promote selective biologic responses

Effect of electromagnetic fields and early postoperative 5-fluorouracil on the healing of colonic anastomoses

Nayci, Ali/0000-0002-0534-1205WOS: 000181357100008PubMed: 12548416Background and aims: Studies have indicated a deleterious effect of perioperative 5-fluorouracil (5-FU) administration on the healing of intestinal anastomoses. This study examined the effect of early postoperative 5-FU on the healing of colonic anastomoses and investigated the effect of electromagnetic fields (EMF) on colonic anastomotic repair under normal physiological conditions and in the presence of 5-FU therapy in a rat model. Materials and methods: Forty male Wistar rats were randomly assigned into four groups and underwent a standardized left colonic resection and anastomoses. The animals then served as control or received intraperitoneal 5-FU (20 mg/kg per day, 5 days), EMF stimulation (10.76 mT, 50 Hz; 2-h on/10-h off cycles, 7 days) or both, starting on the day of surgery. After 7 days anastomotic healing was assessed by measurement of hydroxyproline content and breaking strength. Results: Hydroxyproline content increased in EMF exposed group (1.53+/-0.11 to 1.92+/-0.11 mug/mg) and in EMF + 5-FU group (1.53+/-0.11 to 1.89+/-0.12 mug/mg). Breaking strength also increased in the EMF group (0.23+/-0.02 to 0.27+/-0.01 MPa) and in the EMF + 5-FU group (0.23+/-0.02 to 0.28+/-0.01 MPa. No differences were found in hydroxyproline content or breaking strength between the 5-FU group and controls. Conclusion: Early postoperative 5-FU administration did not impair the healing of colonic anastomoses in rats. Additionally, EMF stimulation provided a significant gain in colonic anastomotic strength, in rat intestines in control animals and in animals exposed to 5-FU

Segmental dilatation of the ileum and intestinal malrotation

Segmental dilatation of the intestine (SDI) is an uncommon cause of functional intestinal obstruction. Segmental dilatation of the ileum with malrotation was found in a 4-year-old girl presented with recurrent episodes of abdominal pain, nonbilious vomiting and severe growth retardation. She was treated successfully with resection of the dilated segment and end-to-end anastomosis. It is proposed that the association of SDI with malrotation may be a presentation of the failure in 'localized growth activity' of the bowel

The role of the spleen on colonic anastomotic healing

Comelekoglu, Ulku/0000-0001-8060-6333; Nayci, Ali/0000-0002-0534-1205WOS: 000184490200007PubMed: 12893499The role of the spleen on wound healing remains unclear. This study investigates the effect of splenectomy on the healing of colonic anastomoses. Twenty-six Wistar rats were assigned into four groups: sham, splenectomy, anastomoses, and splenectomy and anastomoses. The rats underwent a standardized left colonic resection and primary anastomoses, and/or splenectomy. Bursting pressure and hydroxyproline content were used to evaluate anastomotic healing, five days postoperatively. No differences were found in the bursting pressure and hydroxyproline content between the groups. The present results indicate that splenectomy has no negative effect on the healing of colonic anastomoses in rats

Pouch colon malformation: Case report Kolonik pos anomalisi: Olgu sunumu

Three patients with pouch colon malformation were treated surgically between 1995 and 1997. Babies presented with abdominal distention and bilious vomiting. There was a huge gas shadow occupying more than 50 % of the width of the abdomen on the plain abdominal radiograms. In two cases a colovesical fistula was detected and, there was a colovaginal fistula in the third case. Absence/duplication of the appendix vermiformis and hydrouretero-nephrosis were the associated abnormalities. Initial operations were ileostomy in two patients and cecostomy in one patient. Definitive operations were abdominoperineal pull-through with division of the fistula and tubularization of the colonic pouch