Immunopharmacology of inflammatory bowel disease : effects of glucocorticoids and nicotine on cytokine production

There are a number of different defmitions for inflammatory bowel disease (IBD) to be found in the literature. The defmition accepted by most researchers and clinicians is that the tenn inflammatory bowel disease comprises two, in practice, distinct entities: ulcerative colitis (UC) and Crohn's disease (CD)'. Both disorders are characterized by cbronic relapsing inflammation of parts of the gastrointestinal tract of unknown origin, causing abdominal pain and diarrhoea. Because of the recurrent pattern both diseases show signs of acute inflammation (e.g. influx of granulocytes out of the blood into the mucosa of the intestines) as well as signs of cbronic inflammation (e.g. infiltrates of lymphocytes and macrophages)

Nicotine inhibits cytokine synthesis by mouse colonic mucosa

We examined the in vivo effect of nicotine on the synthesis of (pro-)inflammatory mediators by mouse colonic mucosa. The synthesis of lipid mediators such as the prostanoids prostaglandin E2, 6-keto-prostaglandin F1α and thromboxane B2, the 5-lipoxygenase products leukotriene B4 and leukotriene C4 and the platelet activating factor was not affected, whereas the synthesis of the pro-inflammatory cytokines interleukin-1 β and tumor necrosis factor α was completely abolished. The beneficial effects of smoking and nicotine in ulcerative colitis could be attributed to this inhibition

Detection of vascular morphology by high frequency intravascular ultrasonic imaging

This study was designed to validate the potential clinical utility of intravascular ultrasonic imaging in vitro and in vivo. In vitro studies were performed to assess the accuracy of dimensional and morphological information. In vitro images of human vessels (n = 75) demonstrated that lesion thickness determined echographically closely related with histological samples (r = 0.83). Morphologically, muscular and elastic arteries could be distinguished echographically based on the echogenicity of the arterial media. Close relation was also found in the morphological subtypes of atherosclerosis. Subsequently, intravascular ultrasound was used percutaneously in vivo in 20 patients to obtain images of the iliac and superficial femoral artery. High quality real-time images were obtained. Normal vessels were seen showing pulsatile circular images with a hypoechoic muscular media resulting in a typical three-layered appearance. Diseased arteries revealed non-obstructive and obstructive lumen. At the site of obstruction thinning of the muscular media was evident. Pulsation was not always present. Following dilatation of the obstructive lesion using balloon angioplasty the ultrasonic cross-sections changed drastically revealing plaque rupture, dissection, plaque-free wall rupture, rest stenosis and oedema. We conclude that intravascular ultrasonic imaging is a promising technique to document accurate dimensional and morphological characteristics of human vascular disease for guidance of therapeutic interventions

Validation of quantitative analysis of intravascular ultrasound images

This study investigated the accuracy and reproducibility of a computer-aided method for quantification of intravascular ultrasound. The computer analysis system was developed on an IBM compatible PC/AT equipped with a framegrabber. The quantitative assessment of lumen area, lesion area and percent area obstruction was performed by tracing the boundaries of the free lumen and original lumen. Accuracy of the analysis system was tested in a phantom study. Echographic measurements of lumen and lesion area derived from 16 arterial specimens were compared with data obtained by histology. The differences in lesion area measurements between histology and ultrasound were minimal (mean ± SD: -0.27±1.79 mm2, p>0.05). Lumen area measurements from histology were significantly smaller than those with ultrasound due to mechanical deformation of histologic specimens (-5.38±5.09 mm2, p0.05). Finally, intra- and interobserver variability of our quantitative method was evaluated in measurements of 100 in vivo ultrasound images. The results showed that variations in lumen area measurements were low (5%) whereas variations in lesion area and percent area obstruction were relatively high (13%, 10%, respectively). Results of this study indicate that our quantitative method provides accurate and reproducible measurements of lumen and lesion area. Thus, intravascular ultrasound can be used for clinical investigation, including assessment of vascular stenosis and evaluation of therapeutic intervention