MRI diffusion-weighted imaging (DWI) in pediatric small bowel Crohn disease: correlation with MRI findings of active bowel wall inflammation

Background

Restricted diffusion on diffusion-weighted imaging (DWI) sequences during magnetic resonance enterography (MRE) has been shown in segments of bowel affected by Crohn disease. However, the exact meaning of this finding, particularly within the pediatric Crohn disease population, is poorly understood.

Objective

The purpose of this study was to determine the significance of bowel wall restricted diffusion in children with small bowel Crohn disease by correlating apparent diffusion coefficient (ADC) values with other MRI markers of disease activity.

Materials and methods

A retrospective review of pediatric patients (≤ 18 years of age) with Crohn disease terminal ileitis who underwent MRE with DWI at our institution between May 1, 2009 and May 31, 2011 was undertaken. All of the children had either biopsy-proven Crohn disease terminal ileitis or clinically diagnosed Crohn disease, including terminal ileal involvement by imaging. The mean minimum ADC value within the wall of the terminal ileum was determined for each examination. ADC values were tested for correlation/association with other MRI findings to determine whether a relationship exists between bowel wall restricted diffusion and disease activity.

Results

Forty-six MRE examinations with DWI in children with terminal ileitis were identified (23 girls and 23 boys; mean age, 14.3 years). There was significant negative correlation or association between bowel wall minimum ADC value and established MRI markers of disease activity, including degree of bowel wall thickening (R?=?(?)0.43; P?=?0.003), striated pattern of arterial enhancement (P?=?0.01), degree of arterial enhancement (P?=?0.01), degree of delayed enhancement (P?=?0.045), amount of mesenteric inflammatory changes (P?<?0.0001) and presence of a stricture (P?=?0.02). ADC values were not significantly associated with bowel wall T2-weighted signal intensity, length of disease involvement or mesenteric fibrofatty proliferation.

Conclusion

Increasing bowel wall restricted diffusion (lower ADC values) is associated with multiple MRI findings that are traditionally associated with active inflammation in pediatric small bowel Crohn disease.     

Investigational antiarrhythmic agents: promising drugs in early clinical development

Introduction: Although there have been important technological advances for the treatment of cardiac arrhythmias (e.g., catheter ablation technology), antiarrhythmic drugs (AADs) remain the cornerstone therapy for the majority of patients with arrhythmias. Most of the currently available AADs were coincidental findings and did not result from a systematic development process based on known arrhythmogenic mechanisms and specific targets. During the last 20 years, our understanding of cardiac electrophysiology and fundamental arrhythmia mechanisms has increased significantly, resulting in the identification of new potential targets for mechanism-based antiarrhythmic therapy.

Areas covered: Here, we review the state-of-the-art in arrhythmogenic mechanisms and AAD therapy. Thereafter, we focus on a number of antiarrhythmic targets that have received significant attention recently: atrial-specific K⁺-channels, the late Na⁺-current, the cardiac ryanodine-receptor channel type-2, and the small-conductance Ca²⁺-activated K⁺-channel. We highlight for each of these targets available antiarrhythmic agents and the evidence for their antiarrhythmic effect in animal models and early clinical development.

Expert opinion: Targeting AADs to specific subgroups of well-phenotyped patients is likely necessary to detect improved outcomes that may be obscured in the population at large. In addition, specific combinations of selective AADs may have synergistic effects and may enable a mechanism-based tailored antiarrhythmic therapy.     

A study of difference in serum 25-hydroxyvitamin D concentrations in patients with angiographically-defined coronary disease and healthy subjects

Background

Cardiovascular disease (CVD) is one of the most important causes of death in developing countries. The current study evaluates the serum 25-hydroxyvitamin D (25OHD), phosphate and calcium levels in patients with angiographically-defined coronary artery disease (CAD) and healthy subjects in a sample population in northeastern Iran.

Improvement of isolated rat pancreatic islets function by combination of cerium oxide nanoparticles/sodium selenite through reduction of oxidative stress

Insulin Dependent Diabetes Mellitus (IDDM) is a disease with high incidence with no pure cure therapy yet. In most of cases, these patients need pancreatic islets transplantation that is not completely successful because of oxidative stress happening during isolation and transplantation procedures. In the present study, effective factors in transplantation procedure such as viability, insulin secretion, production of reactive oxygen molecules (ROM), and mitochondrial energy as ATP/ADP ratio were examined in the isolated islets exposed to sodium selenite (Na?SeO?; 0 30 nmol/L), metal form of cerium oxide (100 nm), cerium oxide nanoparticles (100 nm) and combination of Na?SeO? (30 nmol/L)/cerium oxide nanoparticles (100 nm) in a time course (1, 2, 4 and 6 days posttreatment) manner. The results showed a significant increase of cells viability, secretion of insulin, and ATP/ADP ratio and a reduction in ROM by use of sodium selenite, cerium oxide nanoparticles, and especially combination of cerium oxide nanoparticles/sodium selenite. Interestingly, not only no improvement was found with metal form of cerium oxide but also deterioration occurred in tested markers. Results suggest that pretreatment with combination of cerium oxide nanoparticles/sodium selenite can improve transplantation outcome and graft function by control of oxidative stress damage.     

Polymerizable nanoparticulate silica-reinforced calcium phosphate bone cement

Bone cements based on calcium phosphate powder and different concentrations of colloidal silica suspensions were developed. Setting time and washout behavior of the cements were recorded and compared with those of a control group prepared by the same powder phase and distilled water as liquid. The phase composition, compressive strength, and morphology of the cements were determined after incubation and soaking in simulated body fluid. Proliferation of osteoblasts seeded on samples was also determined as a function of time. The results showed that the long setting time, poor compressive strength, and undesirable washout behavior of the cement made with distilled water were considerably improved by adding colloidal silica in a dose-dependent manner. On the basis of XRD and SEM results, both control group and nanosilica-added cements composed of nanosized apatite flakes after 7 days soaking, in addition to tetracalcium phosphate residual for the latter. It was found that the rate of hydraulic reactions that are responsible for conversion of the cement reactants to nanostructured apatite was increased by the presence of colloidal silica. Furthermore, the osteoblasts exhibited better proliferation on nanosilica added cements compared to control one. This study suggests better applied properties for nanosilica-added calcium phosphate cement compared to traditional cements.     

Sexual function in women after surgery for pelvic organ prolapse

Our objective was to evaluate the effect of surgical repair of pelvic organ prolapse on female sexual function. Sixty seven women with pelvic organ prolapse were recruited in the study. Degree of pelvic organ prolapse was assessed using pelvic organ prolapse quantitation (POPQ) staging system. Female sexual function index (FSFI) questionnaire was used to assess sexual function of the cases preoperatively and 12–16 weeks after the operation. Mean age of the cases was 36.03 ± 5.38 years. The total mean FSFI score increased from 15.9 ± 10.7 to 21.9 ± 11.1 (P < 0.05). Domain scores of desire, arousal, lubrication, orgasm, and satisfaction were increased significantly (P < 0.05). The mean score for the pain-free intercourse decreased significantly. Results demonstrated that sexual function was improved postoperatively. Using various instruments to assess female sexual function and differences in demographic and cultural characteristics of study groups might be the reasons of discrepancy between the reports.     

Intramural and subserosal echogenic foci on US in large-bowel intussusceptions: prognostic indicator for reducibility?

Background  In large-bowel intussusceptions, several US signs are known to indicate a lower likelihood of reducibility by enema. US can demonstrate echogenic dots or lines (foci) in the bowel wall, which might indicate an ischemic bowel. Objective  To determine the presence of echogenic intramural and subserosal foci in large-bowel intussusceptions and to evaluate the degree of correlation with reducibility. Materials and methods  Between 2001 and 2008, 74 consecutive US examinations were retrospectively evaluated by two pediatric radiologists for intramural and subserosal echogenic foci, or trapped gas, in the intussusception. The degree of correlation between the sonographic findings and reducibility was evaluated. Results  Of 73 intussusceptions examined by US, 56 (76%) were reducible and 17 (23%) were not reducible. Out of 10 intussusceptions with intramural gas, 11 with subserosal gas, and 14 with intramural and subserosal gas, 8 (80%), 6 (56%), 9 (64%), respectively, were not reducible. The presence of intramural gas or subserosal gas or both predicted a lower chance of reduction, but with regard to the effect of these findings together, intramural gas was the only significant predictor. Conclusion  Having intramural gas in large-bowel intussusception significantly decreases the chance of reduction.