Objective The influencing parameters of solid and fluid computing fields for the scaffolds models with regular square holes were discussed by nonlinear fluid-solid-coupling approaches, the numerical computational results of which the models were regarded as both rigid body and non-linear elasticity were compared as well. Method one direct fluid-solid-coupling approach and two indirect fluid-solid-coupling approaches were adopted, and the calculating reliability of three kinds of fluid-solid coupling methods were verified. Results The solid-fluid-coupling computational results are obtained in light of 12 kinds of scaffolds which were constructed by 3 groups of square side length (50,100 and 150μm) and 4 groups of porosity (61%,65%,77% and 84%). The field parameters of those solid models including stress, strain and displacement and those fluid models including static pressure, velocity, wall shear stress and strain rate are achieved and compared.Conclusions A quiet difference between the results of porous scaffold models as a rigid body and that of non-linear elasticity. The different porosity with the same pore radius or the different pore radius with the same porosity effected the field parameters of solid models and fluid models in varying degrees.

OBJECTIVETo evaluate the effect and possible mechanisms of diabetes control after small intestine exclusion surgery in Goto-Kakizaki (GK) rat with non-obese type 2 diabetes mellitus.

METHODSForty GK rats with non-obese type 2 diabetes mellitus underwent duodenal bypass (Group A, n = 8), which creates a shortcut for ingested nutrients bypassing duodenum alone; duodenal-jejunal bypass (Group B, n = 8), a stomach-preserving RYGB that excludes the duodenum and proximal jejunum; duodenum and total jejunum exclusion (Group C, n = 8); sub-total small intestine exclusion (Group D, n = 8), which creates a shortcut for ingested nutrients bypassing duodenum, jejunum and sub-total ileum; controls were pair-fed (PF) sham-operated and untreated GK rats (Group SO, n = 8). The rats were observed for 24 weeks after surgery. Body weight, food intake and fasting blood glucose level were tested at 0, 1, 3, 6, 12, 24 weeks after the operation in those groups. The concentrations of insulin and glucagon-like peptide-1 (GLP-1) concentrations were measured before (baseline) and then 30, 60, 120, and 180 minutes after OGTT at 0, 12, 24 weeks after the operation.

RESULTSMean operating time of all groups was similar. The mean body weight and food intake decreased significantly at 1 week after surgery (P < 0.01) and with no differences among the groups. Fasting blood glucose level decreased significantly after surgery in all the operation groups through the entire follow-up period (P < 0.05). No significant changes in fasting blood glucose level in SO group was found in 12 weeks after the operation, and it increased at 12 and 24 weeks after. Fasting blood glucose levels in group B decreased significantly compared with group A (P < 0.05), but no difference was found among group B, C and D (P > 0.05). Oral glucose-stimulated peak (30 min) levels of blood insulin and GLP-1 increased markedly in operation groups (A, B, C and D) after surgery (P < 0.01). Compared with group A, peak levels of blood insulin and GLP-1 in group B were strikingly higher (P < 0.05), but no difference was found when compared with group C or D (P > 0.05).

CONCLUSIONSIn spontaneously non-obese type 2 diabetes mellitus rats, small intestinal exclusion including proximal gut is effective in terms of glucose control and has no direct relation with body weight and food intake loss. Restoration of the first-phase insulin secretion and high secretion of GLP-1 in type 2 diabetic subjects after gastrointestinal bypass surgery seem to be helpful to diabetes control. Taking intestinal nutrient absorption into consideration, duodenal-jejunal bypass may be a better surgery for diabetes control.

Animals ; Blood Glucose ; analysis ; Body Weight ; Diabetes Mellitus, Type 2 ; surgery ; Disease Models, Animal ; Duodenum ; surgery ; Intestine, Small ; surgery ; Jejunum ; surgery ; Male ; Random Allocation ; Rats ; Rats, Inbred Strains