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Notes: The numerical large eddy simulation (LES) technique is tested on decaying magnetohydrodynamic (MHD) turbulence. The LES approach allows for a strong reduction in computational cost compared to direct numerical simulations by modeling the effects of the smallest turbulent scales instead of computing them directly. Two small-scale models of eddy-viscosity type are presented for this purpose in combination with a procedure for the self-consistent calculation of the model parameters in the course of the simulation. The method is successfully tested by comparing the obtained results to a high-resolution direct numerical simulation of decaying three-dimensional MHD turbulence. © 2001 American Institute of Physics.

Notes: Different patterns of β-catenin expression in gastric carcinomas: relationship with clinicopathological parameters and prognostic outcome Aims: The cadherin–catenin complex is known to play a critical role in maintenance of cell adhesion. Additionally β-catenin (β-ct) can also take part in signal transduction and nuclear β-ct expression could be correlated with poor prognosis in several malignancies. Since, in gastric cancer, this role of β-ct is still uncertain, we investigated the expression pattern of β-ct as well as the possible prognostic role. Methods and results: β-catenin expression was immunohistochemically investigated in a retrospective series of 401 R0-resected gastric carcinomas. Out of these cases, 54 tumours (13.5%) revealed a preserved membranous β-ct expression similar to that in normal gastric mucosa. In 80 tumours β-ct expression was moderately reduced and in 117 tumours highly reduced. In 150 tumours (37.4%), no or only a weak membranous β-ct expression was found. Additionally, in 53 tumours, a strong β-ct expression could be observed in the cytoplasm with a simultaneous nuclear β-ct immunoreactivity in 17 of these 53 tumours, while nine tumours only showed nuclear immunoreactivity without cytoplasmic staining. There were no significant correlations between the degree of membranous β-ct expression or the different staining pattern (membranous vs. cytoplasmic/nuclear) and the grade of tumour differentiation, the histological tumour type according to Lauren, as well as with the prognostic parameters pT, pN category and vascular invasion. No associations could be found with tumour cell proliferation and the expression of E-cadherin, irrespectively of the different β-ct staining pattern. Univariate analysis revealed no influence on survival, either for membranous or for cytoplasmic/nuclear β-ct expression. Conclusion: Our data on 401 tumours suggest that activation of the Wnt/β-catenin signalling does also occur in a subset of gastric carcinomas. However, in gastric cancer, neither the presence of cytoplasmic/nuclear β-ct expression nor the reduction or loss of membranous β-ct expression is correlated with a specific histological tumour type, tumour progression or prognosis.

Notes: Proton pump inhibitor-based therapy including two antibiotics is the treatment of choice for Helicobacter pylori infection. Oral antibiotic treatment can lead to intestinal overgrowth of potentially pathogenic bacteria.〈section xml:id="abs1-2"〉〈title type="main"〉Aim:To investigate the intestinal microflora before and at different times after H. pylori treatment with omeprazole, clarithromycin and metronidazole.〈section xml:id="abs1-3"〉〈title type="main"〉Methods:Bacterial growth in faecal samples from 51 patients infected with H. pylori was determined qualitatively and quantitatively. During the same period of time, stool samples from 27 H. pylori-negative controls were taken and investigated at the same intervals.〈section xml:id="abs1-4"〉〈title type="main"〉Results:The microflora of H. pylori-infected patients was different from that in H. pylori negative controls. It was characterized by a high concentration of lactobacilli, mainly Lactobacillus acidophilus. Immediately after therapy there was an increased colonization with yeasts, while the growth of lactobacilli and other species was inhibited. Clostridium difficile was cultured from three cases, but without clinical manifestations of pseudomembranous colitis. After 4 weeks of therapy, the microflora returned to normal and was not different from that of the H. pylori-negative control group.〈section xml:id="abs1-5"〉〈title type="main"〉Conclusions:In H. pylori-positive patients the intestinal flora is characterized by an increase in growth of acid-tolerant L. acidophilus. Eradication therapy exerts only a short-term influence on intestinal flora, whereas in the long term, the intestinal microflora is restored to a pattern similar to that of the control group.