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A study of Liesegang band formation is presented with emphasis on the dependence of the precipitation patterns on the initial concentrations of reactants. We have chosen Pb(N03)2 and KI as the interdiffusing electrolytes for periodic precipitation of Pbl2 in an agar-agar gel. Four series of experiments are reported in which we investigate the influence of the electrolytes on the number N, the location x", and the width Awn of bands. The experiments were planned for comparison with structure formation in the absence of gradients and for guidance in a theoretical analysis. (I) Experiments in test tubes placed in the vertical direction in which we varied the concentration of one electrolyte demonstrated that the initial concentration difference, A = 1/2[I_] -[Pb2+], and the initial ion product, o ~[Pb2+][I"]2, are useful parameters to characterize the variability of the patterns with concentrations, especially when either A or , beyond 1 cm, we observe that the bands become broader and more diffuse and the spacing coefficients pn = xn+1/x" decrease.

Our study was designed to evaluate cell-free DNA in sera of prostate cancer (PCA) patients as a useful biomarker. Real-time PCR was used to amplify a <200 bp PTGS2 DNA fragment that biochemically characterizes apoptosis and a larger >250 bp Reprimo DNA fragment that defines mostly other cell death entities. The apoptosis index (AI) expresses the ratio of PTGS2 to Reprimo DNA fragments. GSTP1 hypermethylation was assessed to evaluate the amount of tumor-derived DNA. We analyzed serum of 216 patients (168 PCA; 5 incidental PCA; 42 benign prostatic hyperplasia (BPH); 11 healthy individuals). Distinctly elevated concentrations of PTGS2 fragments were detected in PCA compared to BPH and healthy individuals (median: 70.2, 10.5 and 7.1 ng/ml, respectively; p < 0.0001). The AI was significantly increased in PCA vs. BPH patients and healthy individuals (6.01 vs. 1.54 and 0.84 respectively; p 5 0.002-0.0001). GSTP1 hypermethylation was only present in a small percentage (mean 1.92%) of circulating DNA. Concentrations of apoptotic PTGS2 fragments discriminated sensitively (88%) and specifically (64%) between BPH and PCA, whereas the AI was more specific (82%) but less sensitive (70%). The AI correlated with histological grading (p 5 0.044). Kaplan-Meier analysis for a subset of 124 patients revealed a significant correlation between apoptotic PTGS2 fragments or the AI and PSA recurrence following radical prostatectomy (p 5 0.0395-0.0482). In conclusion, circulating PTGS2 fragments of apoptotic origin and the AI are promising serum biomarkers for the diagnosis and prognosis of PCA. We suggest that cancer-induced apoptosis of peripheral noncancerous tissues is relevant in many malignancies. ' 2007 Wiley-Liss, Inc.Key words: prostate cancer; cell-free DNA; apoptosis; serum Prostate cancer (PCA) is one of the most common malignancies in the world. 1 The most common diagnostic tool is digital rectal examination, but diagnostic accuracy is very limited. Testing of serum prostate specific antigen (PSA) during the last 2 decades improved the diagnosis of PCA. Nevertheless, serum PSA has several drawbacks: (i) its specificity is limited and 60-70% of PSA elevations are caused by nonmalignant disease 2 ; (ii) a number of high-grade tumors are overlooked as patients' PSA levels are in the normal range 2 ; (iii) many clinically insignificant PCA are overdiagnosed. 3 In summary, the development of an improved cancer indicator is essential.In the late 1970s, cell-free DNA was detected in the plasma of cancer patients. 4 The development of PCR-based methods facilitated the quantification of these extremely small amounts of DNA. It was observed that cell-free DNA concentrations are increased in cancer patients compared to healthy individuals and patients with nonmalignant disease. 5 More recently, it was shown that plasma DNA levels may even correlate to disease-specific survival in patients with metastasis. 6 Some reports 7 demonstrate that especially smaller DNA fragments (<200 bp) are present in cancer patients whereas other groups 8 ...

ESWL of impacted ureteral or caliceal stones is not as successful as expected. To study this problem a model for extracorporeal shock wave lithotripsy of ureteral stones has been designed. After initial fragmentation of the outer shell of impacted stones during the first series of shock wave application those fragments are kept in place by external mucosal contact, creating a lot of new interfaces. Absorption or reflection of shock wave energy within this fragmented shell seems to be responsible for the poor success rate in these cases. In regard to our experimental and clinical results we advise pushing ureteral stones back into the renal collecting system by means of a ureteral catheter.

There is currently considerable interest in definitive characterization of organoperoxy radicals in aqueous media because these radicals seem to play key roles in many chemical (e.g., autoxidation) and biochemical (e.g., lipid peroxidation) reac-

Cell-free DNA levels are increased in patients with testicular cancer and they allow the accurate discrimination of healthy individuals. The high sensitivity of cell-free DNA could facilitate the management of testicular cancer, especially in patients with conventional tumor markers that are not increased.

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