Increased mucosal inflammatory cytokines in children with Helicobacter pylori-associated gastritis

The concentrations of tumour necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and IL-1-β in tissue homogenates of gastric mucosal biopsy specimens, and in gastric juice samples from Helicobacter pylori-positive and -negative children, were determined. The study population comprised 30 children with recurrent abdominal pain attending upper gastrointestinal endoscopy. Of these patients 18 were infected with H. pylori. Cytokine concentrations in gastric biopsy homogenate supernatants and in gastric juice were measured by enzyme-linked immunosorbent assay (ELISA). TNF-α levels in gastric juice and in gastric biopsy homogenate supernatants in patients with H. pylori-positive gastritis were found to be significantly higher than those in children without H. pylori infection. IL-6 levels were also higher in H. pylori -infected subjects, but the difference in IL-6 concentrations measured in gastric juice and biopsy homogenate supernatants did not reach statistical significance. IL-1-β concentrations in both specimens showed no significant difference between the two groups of children. It was suggested that increased levels of inflammatory cytokines, especially TNF-α and IL-6 generated locally within the gastric mucosa might be implicated in the pathogenesis of H. pylori-associated gastritis in childhood.     

Investigation of critical factors for the resolution of SR695, a key impurity, from efavirenz in the reversed-phase assay of efavirenz dosage forms

An investigation of the critical factors effecting the resolution of SR695 from efavirenz in the assay of efavirenz by reversed-phase HPLC was performed. This study was implemented to address the inability of a subset of the Zorbax SB-CN columns used in this method to adequately perform this separation, which were otherwise indistinguishable from columns of this type that could. In this study, column temperature, detector time-constant, pre-gradient isocratic hold-time, pre-column mixing volume, column, and HPLC type were considered. Experimental Design methods were employed to find the relative importance of these factors and to find parameters that would optimize the resolution of SR695 and efavirenz on any HPLC, with any column of this type, for both efavirenz oral liquid and capsule samples. It was also desired that this method change be minimal, so that extensive revalidation would not be required. The most important factors were the column temperature, with lower temperatures giving better resolution, and pre-column mixing volume of sample with mobile phase, with higher mixing volumes giving better resolution up to an asymptote reached at around 150 microl. Added pre-gradient isocratic hold time was found to result in a small improvement in resolution, but was insignificant compared with the other factors mentioned above. A possible explanation is given for the mechanism by which temperature and pre-column mixing have this effect on the resolution obtained in this assay.     

II. Uterine fibroid embolization: technical aspects

Successful superselective catheterization of the uterine artery requires familiarity with female pelvic arterial anatomy, knowledge of effective catheter and guidewire combinations, and a few tricks. A learning curve can be expected for each of these elements, although it is assumed that the operator will already have experience in basic catheter techniques. Safe transcatheter delivery, understanding of embolization end points, and avoidance of nontarget embolization are essential. Equally important are knowledge of the properties of the embolic agents currently available and their indications for use. Uterine fibroid embolization unavoidably results in radiation exposure to the uterus and ovaries, and adherence to meticulous fluoroscopic technique is crucial to keep the absorbed dose as low as possible.