PREOPERATIVE MANOMETRY FOR THE SELECTION OF OBESE PEOPLE CANDIDATE TO SLEEVE GASTRECTOMY

ABSTRACT Background: Sleeve gastrectomy may alter esophageal motility and lower esophageal sphincter pressure. Aim: To detect manometric changings in the esophagus and lower esophageal sphincter before and after sleeve gastrectomy in order to select patients who could develop postoperative esophageal motilitity disorders and lower esophageal sphincter pressure modifications. Methods: Seventy-three patients were selected. All were submitted to manometry before the operation and one year after. The variables analyzed were: resting pressure of the lower esophageal sphincter, contraction wave amplitude, duration of contraction waves, and esophageal peristalsis. Data were compared before and after surgery and to the healthy and non-obese control group. Exclusion criteria were: previous gastric surgery, reflux symptoms or endoscopic findings of reflux or hiatal hernia, diabetes and use of medications that could affect esophageal or lower esophageal sphincter motility. Results: 49% of the patients presented preoperative manometric alterations: lower esophageal sphincter hypertonia in 47%, lower esophageal sphincter hypotonia in 22% and increase in contraction wave amplitude in 31%. One year after surgery, manometry was altered in 85% of patients: lower esophageal sphincter hypertonia in 11%, lower esophageal sphincter hypotonia in 52%, increase in contraction wave amplitude in 27% and 10% with alteration in esophageal peristalsis. Comparing the results between the preoperative and postoperative periods, was found statistical significance for the variables of the lower esophageal sphincter, amplitude of contraction waves and peristalsis. Conclusion: Manometry in the preoperative period of sleeve gastrectomy is not an exam to select candidates to this technique.

Physiological roles of connexins in labour and lactation

The connexin family of proteins are best known as oligomerizing to form intercellular membrane channels (gap junctions) that metabolically and ionically couple cells to allow for coordinated cellular function. Nowhere in the body is this role better illustrated than in the uterine smooth muscle during parturition, where gap junctions conduct the contraction wave throughout the tissue to deliver the baby. Parturition is followed by the onset of lactation with connexins contributing to both the dramatic reorganization of mammary gland tissue leading up to lactation and the smooth muscle contraction of the myoepithelial cells which extrudes the milk. This review summarizes what is known about the expression and roles of individual connexin family members in the uterus during labour and in the mammary glands during development and lactation. Connexin loss or malfunction in mammary glands and the uterus can have serious implications for the health of both the mother and the newborn baby.

Development of a Multi-Phase Flow Model for Simulating Solid Particle Motion in the Stomach

Functions of the stomach are storage, mixing and emptying of gastric contents. Among these functions, we focus on the gastric mixing. The stomach shows an antral contraction wave (ACW) that propagates from the proximal antrum to the pylorus. Previous studies using high-resolution concurrent manometry and magnetic resonance imaging (MRI) have suggested that the ACW plays an important role in the gastric mixing. However it is difficult to observe in vivo intragastric fluid motion in detail.

A Mathematical Simulation of the Ureter: Effects of the Model Parameters on Ureteral Pressure/Flow Relations

Ureteral peristaltic mechanism facilitates urine transport from the kidney to the bladder. Numerical analysis of the peristaltic flow in the ureter aims to further our understanding of the reflux phenomenon and other ureteral abnormalities. Fluid-structure interaction (FSI) plays an important role in accuracy of this approach and the arbitrary Lagrangian–Eulerian (ALE) formulation is a strong method to analyze the coupled fluid-structure interaction between the compliant wall and the surrounding fluid. This formulation, however, was not used in previous studies of peristalsis in living organisms. In the present investigation, a numerical simulation is introduced and solved through ALE formulation to perform the ureteral flow and stress analysis. The incompressible Navier–Stokes equations are used as the governing equations for the fluid, and a linear elastic model is utilized for the compliant wall. The wall stimulation is modeled by nonlinear contact analysis using a rigid contact surface since an appropriate model for simulation of ureteral peristalsis needs to contain cell-to-cell wall stimulation. In contrast to previous studies, the wall displacements are not predetermined in the presented model of this finite-length compliant tube, neither the peristalsis needs to be periodic. Moreover, the temporal changes of ureteral wall intraluminal shear stress during peristalsis are included in our study. Iterative computing of two-way coupling is used to solve the governing equations. Two phases of nonperistaltic and peristaltic transport of urine in the ureter are discussed. Results are obtained following an analysis of the effects of the ureteral wall compliance, the pressure difference between the ureteral inlet and outlet, the maximum height of the contraction wave, the contraction wave velocity, and the number of contraction waves on the ureteral outlet flow. The results indicate that the proximal part of the ureter is prone to a higher shear stress during peristalsis compared with its middle and distal parts. It is also shown that the peristalsis is more efficient as the maximum height of the contraction wave increases. Finally, it is concluded that improper function of ureteropelvic junction results in the passage of part of urine back flow even in the case of slow start-up of the peristaltic contraction wave.