Current Status on Stem Cells and Cancers of the Gastric Epithelium

Gastric cancer is still a leading cause of cancer-related mortality worldwide in spite of declining incidence. Gastric cancers are, essentially, adenocarcinomas and one of the strongest risk factors is still infection with Helicobacter pylori. Within the last years, it became clear that gastric self-renewal and carcinogenesis are intimately linked, particularly during chronic inflammatory conditions. Generally, gastric cancer is now regarded as a disease resulting from dysregulated differentiation of stem and progenitor cells, mainly due to an inflammatory environment. However, the situation in the stomach is rather complex, consisting of two types of gastric units which show bidirectional self-renewal from an unexpectedly large variety of progenitor/stem cell populations. As in many other tumors, cancer stem cells have also been characterized for gastric cancer. This review focuses on the various gastric epithelial stem cells, how they contribute to self-renewal and which routes are known to gastric adenocarcinomas, including their stem cells.     

A single-phase algorithm for mining high utility itemsets using compressed tree structures

Mining high utility itemsets (HUIs) from transaction databases considers such factors as the unit profit and quantity of purchased items. Two-phase tree-based algorithms transform a database into compressed tree structures and generate candidate patterns through a recursive pattern-growth procedure. This procedure requires a lot of memory and time to construct conditional pattern trees. To address this issue, this study employs two compressed tree structures, namely, Utility Count Tree and String Utility Tree, to enumerate valid patterns and thus promote fast utility computation. Furthermore, the study presents an algorithm called single-phase utility computation (SPUC) that leverages these two tree structures to mine HUIs in a single phase by incorporating novel pruning strategies. Experiments conducted on both real and synthetic datasets demonstrate the superior performance of SPUC compared with IHUP, UP-Growth, and UP-Growth+ algorithms.     

Lignin from Annual Plants as Raw Material Source for Flavors and Basic Chemicals

The enzymatic conversion of lignins, possibly in combination with electrochemical oxidation, makes aromatics such as syringol, guaiacol, vanillin and catechol available in the qualities required by the fragrance industry. The lignins were obtained by soda digestion from wheat straw and Miscanthus, characterized and then converted with laccases. The overall yield amounted up to 9 wt % with a product spectrum confined to four substances. Catechol was the major product, with a fraction of ≈75 %. It can easily be isolated by extraction with acetone.     

Effect of hygiene measures, water sanitation and oral rehydration therapy on diarrhea in children less than five years old in the south of Ivory Coast

BACKGROUND: Gastric sucrose permeability is a noninvasive marker that reliably increases in association with gastrointestinal injury due to use of nonsteroidal antiinflammatory drugs. Despite the effect of Helicobacter pylori infection on the gastric mucosa, in a previous study we were unable to demonstrate that H. pylori infection was associated with abnormal gastric sucrose permeability. Our goal in this study was to explore further whether H. pylori infection changed gastric permeability; therefore, we evaluated the effect of treatment of H. pylori infection on gastric permeability to sucrose and the relation of sucrose permeability to density of polymorphonuclear leukocytes. MATERIALS AND METHODS: Five hundred milliliters of a solution containing 100 gm of sucrose was ingested by the subject at bedtime. Overnight urine was collected and assayed for sucrose by high-performance liquid chromatography. Sucrose permeability was assessed both before and approximately 4 weeks after anti-H. pylori therapy. RESULTS: Seventeen asymptomatic H. pylori-infected volunteers participated; 8 were cured. Sucrose permeability was in the range commonly found in normal controls both before and after anti-H. pylori therapy (mean excretion, 76.3 mg; range, 13-171 mg). Gastric sucrose permeability correlated with the density of polymorphonulcear cell infiltration of the mucosa. Cure of the H. pylori infection was associated with a small but significant decrease in sucrose permeability (98.8 +/- 18 mg to 51.7 +/- 9.8 mg (p = .01). Sucrose permeability was greater in those with a high density of mucosal polymorphonuclear cells compared to those with lower scores (119.5 +/- 4 vs 71.4 +/- 13 for those with scores > or = 5 compared to scores < or = 4; p = .023). Failed therapy resulted in an increase in the mucosal density of polymorphonuclear infiltration and sucrose permeability (56.4 +/- 13 mg-99.7 +/- 19 mg pretreatment vs posttreatment, respectively; p = .031). CONCLUSION: H. pylori gastritis causes a small but measurable increase in gastric permeability to sucrose that may reflect epithelial transmigration of neutrophils.     

The utility and cost-effectiveness of D-dimer measurements in the diagnosis of deep vein thrombosis

BACKGROUND AND OBJECTIVE: The potential utility of D-dimer measurements for the diagnosis of deep vein thrombosis became evident soon after the development of reliable commercial assays. The purpose of this review is to outline some critical aspects affecting cost-effectiveness of D-dimer measurements in the diagnosis of deep vein thrombosis (DVT). METHODS: The authors have been working in this field contributing original papers whose data have been used for this study. In addition, the material analyzed in this article includes papers published in the journals covered by the Science Citation Index and Medline. RESULTS: D-dimer levels are very sensitive to the process of fibrin formation/dissolution occurring with ongoing thrombosis. However, they may not be highly specific for venous thromboembolism as they are influenced by the presence of comorbid conditions potentially elevating plasma D-dimer (cancer, surgery, infectious diseases). In addition, commercially available ELISA assays, although quantitative and reproducible, cannot be used under emergency conditions because they are time-consuming and suited for batch-processing of plasma samples. Recently, new assays have been introduced which permit fast and quantitative D-dimer estimations in individual patients. We have evaluated the utility of two new rapid assays (LPIA D-dimer. Mitsubishi, and VIDAS D-DIMER, bio-Merieux) in combination with compression real-time-B-mode ultrasonography for the detection of deep vein thrombosis in asymptomatic patients following elective hip replacement and in patients with clinically suspected deep vein thrombosis. In both settings, we identified cut-off values with optimal sensitivity which allow exclusion of deep vein thrombosis in a considerable percentage of patients, with substantial sparing of economic resources. In fact, based on a cost-effectiveness analysis, a diagnostic algorithm combining D-dimers measurement and compression ultrasonography would result in cost-savings ranging from 5% to 55% in patients with high or low clinical pretest probability respectively. However, the specificity of D-dimer measurements for deep vein thrombosis was much higher in symptomatic than in asymptomatic patients. Choice of the cut-off value proved to be dependent on the method as well as on the patient populations studied. CONCLUSIONS: The cost-effectiveness of D-dimers measurement in the diagnosis of asymptomatic DVT remains questionable. Conversely, our data strongly support the utility of D-dimers determinations in the diagnosis of symptomatic DVT. In terms of sparing economic resources, the introduction in the clinical laboratory of the rapid quantitative assays would be highly convenient, because they avoid a source of bias in the interpretation of D-dimers results, are easy to perform and do not require dedicated personnel or instrumentation. Prospective management studies validating the utility of D-dimer measurement in the diagnosis of deep vein thrombosis are urgently needed.     

Molecular mechanisms in the control of limb regeneration: the role of homeobox genes

The Ca2+ sensitivity of cardiac myofibrillar force production can be decreased by acidosis or inorganic phosphate (P(i)) and increased by caffeine. To investigate whether the source of tissue influences the potency of these agents, we compared the actions of acidosis (change of pH from 7.0 to 6.2), P(i) and caffeine (both 20 mM) on force production of skinned cardiac muscles from adult ventricle, adult atrium and neonate ventricle of the rat. Maximum Ca(2+)-activated force was reduced by all three interventions and the responses of the different muscle types to a given intervention were similar. Acidosis reduced myofibrillar Ca2+ sensitivity by 1.09 and 1.04 pCa units in adult ventricle and atrium, respectively, and P(i) reduced it by 0.19 and 0.22 pCa units. However, each effect was only one-third as great in the neonate ventricle, which showed falls of 0.33 pCa units for acidosis and 0.06 for P(i). In contrast, caffeine raised the Ca2+ sensitivity by the same amount (approximately 0.4 pCa units) in all three muscle types. The differential effect between adult and neonate seen with both acidosis and P(i) suggests some similarity in the mechanisms by which these factors decrease Ca2+ sensitivity. In contrast, the equal effects of caffeine on neonate and adult suggests that caffeine acts by a completely different mechanism. The lower pH- and P(i)-sensitivity of the neonatal ventricle can help to explain why neonatal and adult myocardium exhibit differential force responses to ischaemia (or hypoxia alone).     

Theory of Seepage into an Auger Hole in a Confined Aquifer Overlying a Gravel Substratum

An analytical solution is presented to the problem of steady groundwater flow seeping into a pumped cylindrical hole partially penetrating a homogeneous and anisotropic confined aquifer overlying a gravel substratum. Solutions are obtained for two general cases of the problem: (1) when the level of the pumped hole is below the confining layer; (2) when it is above it. The validity of the proposed theory is tested by comparing analytical predictions obtained for a few flow situations with corresponding results obtained by numerical means. The theory presented here can be utilized to convert the rate of rise of water in a pumped auger hole into directional conductivities of soil, in areas where water is found to be in a confined state overlying a gravel substratum. The study shows that the conductivity values calculated by neglecting the confining pressure of an artesian aquifer with a gravel base [i.e., by applying the existing (Boast and Kirkham in 1971), auger hole seepage theory for a phreatic aquifer with a gravel base to confined situations] may result in serious error; hence, the artesian head of an aquifer must be accounted for while computing the conductivity values. Further, it is observed that the area contributing flow to a pumped auger hole/well with a gravel base is mostly restricted to a short radial distance from the center of the hole, particularly for situations where the gravel substratum is located close to the bottom of the hole. This is in contrast to auger hole flow situations overlying an impervious substratum, where the domain contributing flow is mostly spread out to a considerable distance from the center of the hole.