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Background and Aims It is uncertain whether ulcerative colitis leads to accumulated bowel damage on cross-sectional image. We aimed to characterise bowel damage in patients with ulcerative colitis using magnetic resonance imaging [MRI], and to determine its relation with duration of disease and the impact on patients' quality of life. Methods In this prospective study, patients with ulcerative colitis [UC] in endoscopic remission underwent MRI without bowel cleansing, and completed quality-of-life questionnaires. Participants' magnetic resonance findings were analysed considering normal values and thresholds determined in controls with no history of inflammatory bowel disease [ n =40], and in patients with Crohn's disease with no history of colonic involvement [ n  = 12]. Subjects with UC were stratified according to disease duration [< 7 years vs 7‒14 years vs > 14 years]. Results We analysed 41 subjects with ulcerative colitis [20 women; Mayo endoscopic subscore 0 in 38 [92.7%] and 1 in three [7.3%]]. Paired segment-by-segment comparison of magnetic resonance findings in colonic segments documented as being affected by ulcerative colitis versus controls showed that patients with ulcerative colitis had decreased cross-sectional area [ p  ≤ 0.0034] and perimeter [ p  ≤ 0.0005] and increased wall thickness [ p  = 0.026] in all segments. Colon damage, defined as wall thickness ≥ 3 mm, was seen in 22 [53.7%] patients. Colon damage was not associated with disease duration or quality of life. Conclusions Morphological abnormalities in the colon were highly prevalent in patients with ulcerative colitis in the absence of inflammation. Structural bowel damage was not associated with disease duration or quality of life. [ABSTRACT FROM AUTHOR]

A simple technique to isolate a PK-sensitive fraction of Pr[P.sup.Sc] is described. The analysis of the biochemical properties, composed by a light fraction of Pr[P.sup.Sc] oligomers demonstrate that it has prion-converting activity and is susceptible to digestion by particular proteolytic enzymes like trypsin.

One of the main characteristics of the transmissible isoform of the prion protein (PrPSc ) is its partial resistance to proteinase K (PK) digestion. Diagnosis of prion disease typically relies upon immunodetection of PK-digested PrPSc following Western Sc blot or ELISA. More recently, researchers determined that there is a sizeable fraction of PrPSc that is sensitive to PK hydrolysis (sPrPSc). Our group has previously reported a method to isolate this fraction by centrifugation and showed that it has Sc protein misfolding cyclic amplification (PMCA) converting activity. We compared the infectivity of the sPrPSc versus the PK- resistant (rPrP Sc) fractions of PrP and analyzed the biochemical characteristics of these fractions under conditions of limited proteolysis. Our results show that sPrP Sc and rPrPSc fractions have comparable degrees of infectivity and that although they contain different sized multimers, these multimers share similar structural properties. Furthermore, the PK- sensitive fractions of two hamster strains, 263K and Drowsy (Dy), showed strain-dependent differences in the ratios of the sPrPSc to the rPrPSc forms of PrPSc. Although the sPrPSc and rPrPSc fractions have different resistance to PK-digestion, and have previously been shown to sediment differently, and have a different distribution of multimers, they share a common structure and phenotype. [ABSTRACT FROM AUTHOR]

Recent studies have shown that a sizable fraction of PrPSc present in prion-infected tissues is, contrary to previous conceptions, sensitive to digestion by proteinase K (PK). This finding has important implications in the context of diagnosis of priori disease, as PK has been extensively used in attempts to distinguish between PrPSc and PrPC. Even more importantly, PK-sensitive PrPSc (sPrPSc) might be essential to understand the process of conversion and aggregation of PrPC leading to infectivity. We have isolated a fraction of sPrPSc. This material was obtained by differential centrifugation at an intermediate speed of Syrian hamster PrPSc obtained through a conventional procedure based on ultracentrifugation in the presence of detergents. PK-sensitive PrPSc is completely degraded under standard conditions (50 μg/mL of proteinase K at 37 °C for 1 h) and can also be digested with trypsin. Centrifugation in a sucrose gradient showed sPrPSc to correspond to the lower molecular weight fractions of the continuous range of oligomers that constitute PrPSc. PK-sensitive PrPSc has the ability to convert PrPC into protease-resistant PrPSc, as assessed by the protein misfolding cyclic amplification assay (PMCA). Limited proteolysis of sPrPSc using trypsin allows for identification of regions that are particularly susceptible to digestion, i.e., are partially exposed and flexible; we have identified as such the regions around residues K110, R136, R151, K220, and R229. PK-sensitive PrPSc isolates should prove useful for structural studies to help understand fundamental issues of the molecular biology of PrPSc and in the quest to design tests to detect preclinical priori disease. [ABSTRACT FROM AUTHOR]

One of the main characteristics of the transmissible isoform of the prion protein (PrPSc ) is its partial resistance to proteinase K (PK) digestion. Diagnosis of prion disease typically relies upon immunodetection of PK-digested PrPSc following Western Sc blot or ELISA. More recently, researchers determined that there is a sizeable fraction of PrPSc that is sensitive to PK hydrolysis (sPrPSc). Our group has previously reported a method to isolate this fraction by centrifugation and showed that it has Sc protein misfolding cyclic amplification (PMCA) converting activity. We compared the infectivity of the sPrPSc versus the PK- resistant (rPrP Sc) fractions of PrP and analyzed the biochemical characteristics of these fractions under conditions of limited proteolysis. Our results show that sPrP Sc and rPrPSc fractions have comparable degrees of infectivity and that although they contain different sized multimers, these multimers share similar structural properties. Furthermore, the PK- sensitive fractions of two hamster strains, 263K and Drowsy (Dy), showed strain-dependent differences in the ratios of the sPrPSc to the rPrPSc forms of PrPSc. Although the sPrPSc and rPrPSc fractions have different resistance to PK-digestion, and have previously been shown to sediment differently, and have a different distribution of multimers, they share a common structure and phenotype. [ABSTRACT FROM AUTHOR]

Conventional diagnostic magnetic resonance imaging (MRI) techniques have focused on improving the spatial resolution and image acquisition speed (whole-body MRI) or on new contrast agents. Most advances in MRI go beyond morphologic study to obtain functional and structural information in vivo about different physiological processes of tumor microenvironment, such as oxygenation levels, cellular proliferation, or tumor vascularization through MRI analysis of some characteristics: angiogenesis (perfusion MRI), metabolism (MRI spectroscopy), cellularity (diffusion-weighted MRI), lymph node function, or hypoxia [blood-oxygen-level-dependent (BOLD) MRI]. We discuss the contributions of different MRI techniques than must be integrated in oncologic patients to substantially advance tumor detection and characterization risk stratification, prognosis, predicting and monitoring response to treatment, and development of new drugs.

Pheochromocytoma is a catecholamine-producing tumor and a rare cause of hypertension. Most cases are intra-adrenal and intrapericardial pheochromocytomas are extremely uncommon. We report the case of a 46-year-old woman with a 1-year history of hypertension, in which a right atrial pheochromocytoma was detected after a hypertensive crisis. 131I-metaiodobenzylguanidine scintigraphy and magnetic resonance imaging established the diagnosis. The tumor was successfully resected using cardiopulmonary bypass and the right atrium was reconstructed using bovine pericardium.