Phosphatidylinositol 3-kinase activation is required for sulfonylurea stimulation of glucose transport in rat skeletal muscle

Sulfonylureas are drugs widely used in the treatment of patients with type 2 diabetes mellitus. In addition to their pancreatic effect of stimulating insulin secretion, many studies suggest that sulfonylureas also have extrapancreatic actions. We have previously reported that gliclazide, a second-generation sulfonylurea, stimulates the glucose uptake by rat hindquarter skeletal muscle directly and immediately by promoting the translocation of glucose transporter 4 to the plasma membrane. The aim of our study was to approach the gliclazide intracellular signaling pathway. For this purpose, we incubated clamped and isolated soleus muscle from rat with gliclazide. The following results were obtained: 1) gliclazide stimulates insulin receptor substrate (IRS)-1-phosphatidylinositol 3 (PI3)-kinase-associated activity, and this activity is necessary for gliclazide-stimulated glucose transport; 2) gliclazide treatment produces a gradual translocation of the diacylglycerol (DAG)-dependent isoforms protein kinase C (PKC) alpha, theta, and epsilon from cytosolic to membrane fraction that is dependent on PI3-kinase and phospholipase C (PLC)-gamma activation; and 3) PKC and PLC-gamma activation is necessary for gliclazide-stimulated glucose transport. We propose a hypothetical signaling pathway by which gliclazide could stimulate IRS-1 that would allow its association with PI3-kinase, promoting its activation. PI3-kinase products could induce PLC-gamma activation, whose hydrolytic activity could activate the DAG-dependent isoforms PKC alpha, theta, and epsilon.     

Cholecystokinin antagonist L364,718 induces alterations in acinar cells that prevent improvement of acute pancreatitis induced by obstruction

The aim of this study was to examine the effect of the most potent CCK receptor antagonist, L364,718, on two major factors involved in pancreatitis development: enzyme load and cytosolic calcium (Ca²⁺) levels in acinar cells. L364,718 (0.1 mg/kg/12 hr) was administered from 30 min before inducing acute pancreatitis (AP) by pancreatic duct obstruction (PDO) for 48 hr. The results obtained at different AP stages in PDO rats treated and not treated with the CCK antagonist were compared. Similar increases in the intracellular enzyme content were found at earlier stages of pancreatitis in all PDO rats treated or not treated with L364,718. The CCK antagonist increased cytosolic Ca²⁺ levels up to 6 hr after administration, inducing a higher cytosolic Ca²⁺ overload at the earliest stages of pancreatitis in L364,718-treated PDO rats than in those not treated. This event might justify the higher increases in ascites volume and haematocrit found in PDO rats treated with L364,718 and the exacerbation in pancreatic morphological alterations induced by PDO. The CCK receptor antagonist L364,718 produces alterations in the acinar calcium homeostasis that prevent to reduction in the severity of pancreatitis induced by obstruction.     

Buscando la burbuja: aire torácico extrapulmonar atípico e inusual

ObjectiveTo describe the radiologic findings of extrapulmonary air in the chest and to review atypical and unusual causes of extrapulmonary air, emphasizing the importance of the diagnosis in managing these patients.ConclusionIn this article, we review a series of cases collected at our center that manifest with extrapulmonary air in the thorax, paying special attention to atypical and uncommon causes. We discuss the causes of extrapulmonary according to its location: mediastinum (spontaneous pneumomediastinum with pneumorrhachis, tracheal rupture, dehiscence of the bronchial anastomosis after lung transplantation, intramucosal esophageal dissection, Boerhaave syndrome, tracheoesophageal fistula in patients with esophageal tumors, bronchial perforation and esophagorespiratory fistula due to lymph-node rupture, and acute mediastinitis), pericardium (pneumopericardium in patients with lung tumors), cardiovascular (venous air embolism), pleura (bronchopleural fistulas, spontaneous pneumothorax in patients with malignant pleural mesotheliomas and primary lung tumors, and bilateral pneumothorax after unilateral lung biopsy), and thoracic wall (infections, transdiaphragmatic intercostal hernia, and subcutaneous emphysema after lung biopsy).     

Development of explicit criteria for cholecystectomy

Objective: Consensus development techniques were used in the late 1980s to create explicit criteria for the appropriateness of cholecystectomy. New diagnostic and treatment techniques have been developed in the last decade, so an updated appropriateness of indications tool was developed for cholecystectomy in patients with non-malignant diseases. The validity and reliability of panel results using this tool were tested.

Methods: Criteria were developed using a modified Delphi panel judgement process. The level of agreement between the panellists (six gastroenterologists and six surgeons) was analysed and the ratings were compared with those of a second different panel using weighted kappa statistics.

Results: The results of the main panel were presented as a decision tree. Of the 210 scenarios evaluated by the main panel in the second round, 51% were found appropriate, 26% uncertain, and 23% inappropriate. Agreement was achieved in 54% of the scenarios and disagreement in 3%. Although the gastroenterologists tended to score fewer scenarios as appropriate, as a group they did not differ from the surgeons. Comparison of the ratings of the main panel with those of a second panel resulted in a weighted kappa statistic of 0.75.

Conclusions: The parameters tested showed acceptable validity and reliability results for an evaluation tool. These results support the use of this algorithm as a screening tool for assessing the appropriateness of cholecystectomy.

     

Collagenase-3 (MMP-13) expression by inflamed mucosa in inflammatory bowel disease

Objective. To determine whether the expression of collagenase-3 (MMP-13) in biopsies from patients with inflammatory bowel disease is correlated with histological inflammation parameters. Material and methods. Fifty-nine patients with inflammatory bowel disease were included in the study. The control group comprised 20 patients free of inflammatory disease and ten patients with acute diverticulitis. MMP-13 expression was determined by immunohistochemical staining and the specimens were assigned a histological inflammation score. Results. It was found that 62.8% of patients with ulcerative colitis (UC) and 54.1% of patients with Crohn's disease (CD) showed MMP-13-positive immunostaining in biopsies from affected areas. MMP-13-positive staining was more intense in ulcerated colonic mucosa. A positive and significant correlation was found between MMP-13 expression and the histological inflammation scores in mucosal samples from patients with CD (r=0.74, p<0.0001) or UC (r=0.62, p<0.0001). However, no MMP-13-positive immunostaining was found in either the biopsy specimens of the control group or those biopsies taken from patients with UC or CD in microscopically confirmed non-affected areas of the colonic mucosa. Similarly, colonic mucosa samples of the 10 patients with acute diverticulitis did not show immunostaining for MMP-13. Conclusions. Our findings demonstrating the absence of MMP-13 expression in non-inflamed colonic mucosa or in acute diverticulitis, as well as a positive correlation between elevated MMP-13 expression and histological criteria of inflammation in patients with inflammatory bowel diseases (CD and UC) suggest a role of the protease in the pathogenesis of these latter processes.     

Characterization of the Plasmodium falciparum Sarcoplasmic/Endoplasmic Reticulum Ca2+-ATPase Gene in Samples from Equatorial Guinea before Implementation of Artemisinin-Based Combination Therapy

Plasmodium falciparum resistance to the primary drugs used for treatment of malaria has become the main obstacle to malaria control. Artemisinin combination therapies are the current treatment strategy, and it has been suggested that resistance to artemisinin derivatives may be related to mutations in the Plasmodium falciparum sarcoplasmic-endoplasmic reticulum Ca²⁺-ATPase ortholog of the mammalian sarco-endoplasmic reticulum Ca²⁺ ATPase gene, known as the pfatp6 gene. Thus, the purpose of this study was to determine the prevalence of single-nucleotide polymorphisms (SNPs) in pfatp6. The presence of different SNPs was detected by polymerase chain reaction amplification of the pfatp6 gene, and then sequencing to identify all possible alleles of the gene. A total of 20 SNPs were detected, including eight SNPs that have not been previously described: K481R in Malabo; R801H on Annobon Island; and the synonymous SNPs a141t, c1788t, a2211g, t2739g, a2760c, and g2836a. The genotypic profile of pfatp6 in samples from Equatorial Guinea, may be a useful epidemiologic tool for monitoring local efficacy of artemisinin combination therapies.