Regulation of mucosal structure and barrier function in rat colon exposed to tumor necrosis factor alpha and interferon gamma in vitro: A novel model for studying the pathomechanisms of inflammatory bowel disease cytokines

Objective. In Inflammatory bowel disease (IBD), elevated cytokines are responsible for disturbed intestinal transport and barrier function. The mechanisms of cytokine action have usually been studied in cell culture models only; therefore the aim of this study was to establish an in vitro model based on native intestine to analyze distinct cytokine effects on barrier function, mucosal structure, and inherent regulatory mechanisms. Material and methods. Rat colon was exposed to tumor necrosis factor alpha (TNFα) and interferon gamma (IFNγ) in Ussing chambers. Transepithelial resistance (R^t) and ³H-mannitol fluxes were measured for characterization of the paracellular pathway. Transcellular transport was analyzed by horseradish peroxidase (HRP) flux measurements. Expression and distribution of tight junction proteins were characterized in immunoblots and by means of confocal laser-scanning microscopy (LSM). Results. Colonic viability could be preserved for 20 h in a specialized in vitro set-up. This was sufficient to alter mucosal architecture with crypt surface reduction. R^t was decreased (101±10 versus 189±10 Ω·cm²) with a parallel increase in mannitol permeability after cytokine exposure. Tight junction proteins claudin-1, -5, -7, and occludin decreased (45±10%, 16±7%, 42±8%, and 42±13% of controls, respectively), while claudin-2 increased to 208±32%. Occludin and claudin-1 translocated from the plasma membrane to the cytoplasm. HRP flux increased from 0.73±0.09 to 8.55±2.92 pmol·h^?1·cm^?2. Conclusions. A new experimental IBD model with native colon in vitro is presented. One-day exposure to TNFα and IFNγ alters mucosal morphology and impairs epithelial barrier function by up-regulation of the paracellular pore-former claudin-2 and down-regulation of the barrier-builders claudin-1, -5, and -7. These alterations resemble changes seen in IBD and thus underline their prominent role in IBD pathogenicity.     

The Effect of a Hypertension Self-Management Intervention on Diabetes and Cholesterol Control

Background

Most patient chronic disease self-management interventions target single-disease outcomes. We evaluated the effect of a tailored hypertension self-management intervention on the unintended targets of glycosylated hemoglobin (HbA_1c) and low-density lipoprotein cholesterol (LDL-C).

Methods

We evaluated patients from the Veterans Study to Improve the Control of Hypertension, a 2-year randomized controlled trial. Patients received either a hypertension self-management intervention delivered by a nurse over the telephone or usual care. Although the study focused on hypertension self-management, we compared changes in HbA_1c among a subgroup of 216 patients with diabetes and LDL-C among 528 patients with measurements during the study period. Changes in these laboratory values over time were compared between the 2 treatment groups using linear mixed-effects models.

Results

For the patients with diabetes, the hypertension self-management intervention resulted in a 0.46% reduction in HbA_1c over 2 years compared with usual care (95% confidence interval, 0.04%-0.89%; P = .03). For LDL-C, there was a minimal 0.9 mg/dL between-group difference that was not statistically significant (95% confidence interval, −7.3-5.6 mg/dL; P = .79).

Conclusions

There was a significant effect of the self-management intervention on the unintended target of HbA_1c,but not LDL-C. Chronic disease self-management interventions might have “spill-over” effects on patients' comorbid chronic conditions.     

Do they teach what they need to? An analysis of the impact of curriculum mapping on the learning objectives taught in a lecture series in surgery

Abstract

Introduction: Curriculum mapping shows concordances and differences between the intended and the taught curriculum. To our knowledge, no previous studies describe the effects that this mapping has on the curriculum. The aim of the present study is to map the content of a lecture series in surgery to the National Catalogue of Learning Objectives in Surgery and analyze the effects this mapping has on the content of the following lecture series.

Methods: All lecturers in the lecture series were directly observed by a minimum of two reviewers and learning objectives and the level of competence were documented. After the lecture series, the results were visualized within the catalog of learning objectives and were sent to the lecturers. In the following lecture series, learning objectives were documented correspondingly.

Results: In the first lecture series, 47% of the learning objectives were taught. After the mapping, the number of learning objectives that were taught increased to 59% (p?<?0.001). The increase was found in all surgical disciplines and in all levels of competences without any changes in the average duration of the lectures.

Conclusions: The presented method for mapping a curriculum effectively increased the number of taught learning objectives without requiring longer lecture durations.     

Autologous and alloplastic breast reconstruction--overview of techniques, indications and results

It is important for any woman undergoing mastectomy to make an informed decision about reconstruction and to be provided with information about the technique, advantages and disadvantages. There is a high degree of patient satisfaction with breast reconstruction, but high levels of preoperative information and psychological support are necessary. Close collaboration between oncological and reconstructive surgeons or management by an oncoplastic breast surgeon, careful patient selection and counseling, and refinements in surgical techniques can provide a range of safe and predictable techniques for breast reconstruction. After modified radical mastectomy breast reconstruction involves replacement of breast skin and breast volume; after skin-sparing mastectomy only the replacement of breast volume is necessary. The most commonly used surgical techniques are tissue expansion, latissimus dorsi myocutaneous flap with or without implants, and the use of lower abdominal tissue. Until today, the pedicled TRAM flap is the standard method for autologous breast reconstruction.     

Catestatin-like immunoreactivity in the rat eye

The aim of the study was to investigate the presence and distribution of the chromogranin A-derived peptide catestatin in the rat eye and trigeminal ganglion by immunofluorescence using an antibody which recognizes not only free catestatin but also larger fragments containing the sequence of catestatin. Western blots were performed in an attempt to characterize the immunoreactivities detected by the catestatin antiserum. Sparse immunoreactive nerve fibers were visualized in the corneal stroma, in the chamber angle, in the sphincter muscle but also in association with the dilator muscle, in the stroma of the ciliary body and processes, but dense in the irideal stroma, around blood vessels at the limbus and in the choroid and in cells of the innermost retina representing amacrine cells as identified by colocalization with substance P. Furthermore, catestatin-immunoreactivity was detected in the trigeminal ganglion in small to medium-sized cells and there were abundant catestatin-positive nerve fibers stained throughout the stroma of the ganglion. Double immunofluorescence of catestatin with substance P revealed colocalization both in cells of the trigeminal ganglion as well as in nerve fibers in the choroid. The immunoreactivities are present obviously as free catestatin and/or small-sized catestatin-containing fragments in the retina and ocular nerves but as large processed fragments as well, weak in the retina and more prominent in remaining ocular tissues, possibly in endothelial cells. This indicates that this peptide is a constituent of sensory neurons innervating the rat eye and the presence in amacrine cells in the retina is typical for neuropeptides. Catestatin is biologically highly active and might be of significance in the pathophysiology of the eye.