A prospective study of methylenetetrahydrofolate reductase and methionine synthase gene polymorphisms, and risk of colorectal adenoma

We examined the relationship between a functional polymorphism (667C-- >T, ala-->val) of the methylenetetrahydrofolate reductase gene (MTHFR) and the risk of colorectal adenomas in the prospective Nurses' Health Study. Among 257 incident polyp cases and 713 controls, the MTHFR val/val polymorphism [relative risk (RR) = 1.35, 95% confidence interval (CI) 0.84-2.17] was not significantly associated with risk of adenomas. This lack of association was observed for both small (RR = 1.36, 95% CI 0.76-2.45) and large (RR = 1.32, 95% CI 0.66-2.66) adenomas. Furthermore, there was no significant interaction between this polymorphism and consumption of either folate, methionine or alcohol. We also examined the relationship of a newly identified polymorphism (asp919gly) of the methionine synthase gene (MS) with the risk of colorectal adenomas in the same population. The MS gly/gly polymorphism was also not significantly associated with risk of colorectal adenomas (RR = 0.66, 95% CI 0.26-1.70). These results, which need to be confirmed in other studies, suggest that the MTHFR val/val polymorphism, which has been previously inversely associated with risk of colorectal cancer, plays a role only in a late stage (adenoma-- >carcinoma) of colorectal tumorigenesis, and/or may protect against malignant transformation in the subset of benign adenomas, which may progress to malignancy.      

Enchondroma and chondrosarcoma

Enchondroma and chondrosarcoma are two of the most commonly encountered primary bone lesions in the typical radiology practice. The purpose of this article is to review the clinical, radiological, and pathological features that distinguish conventional chondrosarcoma from enchondroma. Chondrosarcoma is almost always associated with pain and tends to present in the axial skeleton of middle aged adults. Enchondroma tends to present in young adults in the appendicular skeleton, particularly the hands, and is often an incidental finding. Although both lesions have characteristic radiographic appearances, difficulty separating these two entities most often occurs when a lesion is seen in the long tubular bones. The judicious use of computed tomography, magnetic resonance imaging, and nuclear medicine in conjunction with appropriate clinical data allows the radiologist to establish the correct diagnosis of benign or malignant medullary chondroid lesion in the majority of cases.     

Isolated hyperthermic liver perfusion with high dose tumor necrosis factor alpha in pigs: an experimental study in preparation of clinical Use

Isolated hyperthermic perfusion of the liver was performed for 45 min in 27 pigs via hepatic artery and portal vein at mean inflow temperatures between 40.7 and 41.2 degrees C. In two study groups B and C (n = 9 pigs each) 50 microg recombinant human tumor necrosis factor-alpha (rhTNFalpha) per kg body weight were added to the perfusate, whereas in a control group A liver perfusion was done without rhTNFalpha. Before reperfusion the livers were washed out with Ringer's solution in all groups followed by a protein solution in group C. At 30 and 60 min after reperfusion the maximum systemic rhTNFalpha concentrations were significantly higher in group B with 68 and 61 ng/ml compared to 14.5 and 14.9 ng/ml in group C (p < 0. 05). Mean systemic porcine TNFalpha concentration was significantly higher in group B (217 pg/ml) compared to group C (50 pg/ml) 30 min after reperfusion (p = 0.012). Survival was 7/9 in group A and C and only 2/9 in group B with 6/7 pigs dying due to severe cardiopulmonary failure within 12 h after operation. In surviving pigs of group A and C only mild and transient hepatotoxicity was registered. The presented study underlines the feasibility of high dose rhTNFalpha application in an isolated hyperthermic liver perfusion system. Washout of the liver with a protein solution before reperfusion reduces systemic TNFalpha levels as well as associated lethal cardiocirculatory and hepatotoxic side effects.     

Considerations on the EU definition of a nanomaterial: Science to support policy making

In recent years, an increasing number of applications and products containing or using nanomaterials have become available. This has raised concerns that some of these materials may introduce new risks for humans or the environment. A clear definition to discriminate nanomaterials from other materials is prerequisite to include provisions for nanomaterials in legislation. In October 2011 the European Commission published the ‘Recommendation on the definition of a nanomaterial’, primarily intended to provide unambiguous criteria to identify materials for which special regulatory provisions might apply, but also to promote consistency on the interpretation of the term ‘nanomaterial’. In this paper, the current status of various regulatory frameworks of the European Union with regard to nanomaterials is described, and major issues relevant for regulation of nanomaterials are discussed. This will contribute to better understanding the implications of the choices policy makers have to make in further regulation of nanomaterials. Potential issues that need to be addressed and areas of research in which science can contribute are indicated. These issues include awareness on situations in which nano-related risks may occur for materials that fall outside the definition, guidance and further development of measurement techniques, and dealing with changes during the life cycle.     

Interactions between fibrin and the plasminogen activators produced by cultured endothelial cells

Serum-free conditioned medium (CM) from cultured bovine aortic endothelial cells (BAEs) was fractionated by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate and analyzed for plasminogen activator (PA) activity by fibrin autography. Distinct size forms of PA with molecular weights (mol wt) of 100,000, 74,000, and 52,000 were readily identified by this approach. When fibrinogen and thrombin were added to CM containing these forms, approximately 55% of the total activity was found to associate with the resultant fibrin clot. The other 45% remained free in the supernatant. This relationship did not change at higher fibrin concentrations. Subsequent analysis revealed that only the larger PA forms (mol wt 74,000-100,000) were recovered in the clot. The 52,000 form did not bind to the polymerizing fibrin under these conditions. The fibrin-binding forms also bound to immobilized concanavalin-A and could be separated from those forms that did not interact with fibrin by concanavalin-A affinity chromatography. The PA activity of the separated forms was then compared by assessing their ability to cleave 125I-plasminogen. Although cleavage by the 52,000 mol wt form was apparent, little if any cleavage was initiated by the mixture containing the 74,000-100,000 forms. The addition of fibrin to this sample resulted in the generation of a potent PA activity. These results indicate that cultured BAEs produce multiple forms of PA that differ both in size and in behavior toward fibrin and concanavalin-A. These forms include molecules that functionally and immunochemically resemble human urokinase, and others that resemble human tissue-type PA.     

Stem cell carcinoma of the colon and rectum

Two cases of highly malignant tumors, one originating in the sigmoid colon and the other in the rectum, are presented. Both tumors showed light microscopic, electron microscopic, and immunohistochemical evidence of multidirectional differentiation. The tumors were composed mainly of undifferentiated cells, but focally merging into areas with adenocarcinomatous and squamous differentiation. Ultrastructurally and histochemically, a predominant endocrine differentiation was present in the undifferentiated areas of the tumors. These two cases lend further support to the recent concept of a pluripotential stem cell in the mucosa of the gastrointestinal tract capable of differentiation in several directions.     

Effect of acetylcysteine on prothrombin index in paracetamol poisoning without hepatocellular injury

Acetylcysteine treatment reduces liver damage after paracetamol overdose, but can affect the prothrombin index, which is used to assess the progress of overdose patients. We aimed to assess retrospectively the effect of intravenous acetylcysteine on the prothrombin index in patients with paracetamol poisoning without signs of hepatocellular injury. Prothrombin index had been recorded before, and serially during, acetylcysteine treatment in 87 patients. After initiation of treatment, prothrombin index decreased (mean 0.33, 95% CI 0.29-0.38) in all patients, and was strongly associated with the start of acetylcysteine infusion. In patients with uncomplicated paracetamol poisoning, a fall in this index might be misinterpreted as a sign of liver failure, leading to prolonged treatment time.