[Safety and efficacy of en bloc vs. conventional transurethral resection of bladder tumors: a meta-analysis and systematic review]. / Sicherheit und Effizienz der en bloc vs. konventionellen transurethralen Resektion von Blasentumoren: eine Metaanalyse und systematic Review.

BACKGROUND: En bloc tumor resection of bladder tumors (ERBT) is a novel alternative procedure to conventional resection of bladder tumor (cTURBT), which might help to address common problems of the standard method, such as inadequate detrusor muscle in specimens, high re-resection rates and high recurrence rates. OBJECTIVE: To analyze current data on ERBT in efficacy and safety compared to cTURBT. DATA SOURCES: PubMed. STUDY SELECTION: Two independent authors identified trials based on keywords and inclusion criteria. A third author was consulted in case of discrepancies. Screening keywords: ERBT, en bloc transurethral resection of bladder tumor, TURBT en bloc. A meta-analysis of 13 studies was performed. The effect size was estimated based on odds ratios and mean differences including their corresponding two-sided 95% confidence intervals. DATA SYNTHESIS: The analyzed studies comprised a homogenous collective in terms of tumor size, tumor multiplicity and tumor stage. Operation time did not significantly differ between the methods. Differences were observed in hospitalization and catheterization time in favor of ERBT. Reported complications did not show clear differences. There was significantly more detrusor muscle in the specimens in the ERBT group. No significant differences were found in recurrence up to 2 years of follow-up. CONCLUSION: ERBT is a safe alternative to conventional TURBT with promising features regarding effective resection of detrusor muscle. More standardized data on recurrence rates, different resection modalities and resection margin results are needed.

Persistence, recurrence, and progression rates of superficial bladder tumours after resection using the differentiated technique.

OBJECTIVE: To investigate whether the differentiated resection technique for excising superficial bladder cancer leads to higher recurrence and progression rates as compared with regular resection. SUBJECTS AND METHODS: We evaluated 163 patients, 66 undergoing a differentiated and 97 a regular resection. All patients underwent a routine second resection within 6-10 weeks. Recurrence and progression rates as well as tumour persistence on second resection were analyzed. RESULTS: Patients with differentiated resections of bladder tumours did not have higher tumour recurrence and progression rates. Also, these patients had a significantly higher percentage of tumour-free second resections (p = 0.03). CONCLUSION: The differentiated resection technique for excising superficial bladder cancer has no negative influence on recurrence and progression rates, but it leads to a reduced tumour persistence.

[Minimally-invasive therapy of urinary stones]. / Interventionelle Therapie von Harnsteinen.

Open surgery was the standard therapy for urinary calculi up to about 30 years ago. This changed upon introduction of extracorporeal shockwave lithotripsy (ESWL) in 1980, a procedure that is now the primary therapy for 70 % of the patients in western countries. Simultaneously, endourological procedures like ureterorenoscopy (URS) and percutaneous nephrolithotripsy (PCNL) have been improved, and now, modern small diameter and highly efficient instruments offer an ideal alternative to shockwave lithotripsy. Today, minimally-invasive stone treatment has replaced open stone surgery almost completely. This article introduces ESWL, URS and PCNL and discusses indications, outcomes and limitations.

Cell-cell signaling in the shoot meristem.

The shoot meristem is a proliferating, changing cell population yet displays a stable organization. Recent studies have addressed how signaling processes coordinate the behaviour of shoot meristem cells.

The stem cell population of Arabidopsis shoot meristems in maintained by a regulatory loop between the CLAVATA and WUSCHEL genes.

The higher-plant shoot meristem is a dynamic structure whose maintenance depends on the coordination of two antagonistic processes, organ initiation and self-renewal of the stem cell population. In Arabidopsis shoot and floral meristems, the WUSCHEL (WUS) gene is required for stem cell identity, whereas the CLAVATA1, 2, and 3 (CLV) genes promote organ initiation. Our analysis of the interactions between these key regulators indicates that (1) the CLV genes repress WUS at the transcript level and that (2) WUS expression is sufficient to induce meristem cell identity and the expression of the stem cell marker CLV3. Our data suggest that the shoot meristem has properties of a self-regulatory system in which WUS/CLV interactions establish a feedback loop between the stem cells and the underlying organizing center.

Role of WUSCHEL in regulating stem cell fate in the Arabidopsis shoot meristem.

The shoot meristem gives rise to the aerial parts of higher plants by continuously initiating new organs. The basis of this activity is its ability to maintain a pool of pluripotent stem cells, which are the ultimate source of all tissues of the shoot. In Arabidopsis plants mutant for the WUSCHEL (WUS) gene, the stem cells are misspecified and appear to undergo differentiation. Here, we show that WUS encodes a novel homeodomain protein which presumably acts as a transcriptional regulator. The pattern of WUS expression suggests that stem cells in the shoot meristem are specified by an underlying cell group which is established in the 16-cell embryo and becomes localized to its prospective domain of function by asymmetric cell divisions.

Role of the ZWILLE gene in the regulation of central shoot meristem cell fate during Arabidopsis embryogenesis.

Postembryonic development in higher plants is marked by repetitive organ formation via a self-perpetuating stem cell system, the shoot meristem. Organs are initiated at the shoot meristem periphery, while a central zone harbors the stem cells. Here we show by genetic and molecular analyses that the ZWILLE (ZLL) gene is specifically required to establish the central-peripheral organization of the embryo apex and that this step is critical for shoot meristem self-perpetuation. zll mutants correctly initiate expression of the shoot meristem-specific gene SHOOT MERISTEMLESS in early embryos, but fail to regulate its spatial expression pattern at later embryo stages and initiate differentiated structures in place of stem cells. We isolated the ZLL gene by map-based cloning. It encodes a novel protein, and related sequences are highly conserved in multicellular plants and animals but are absent from bacteria and yeast. We propose that ZLL relays positional information required to maintain stem cells of the developing shoot meristem in an undifferentiated state during the transition from embryonic development to repetitive postembryonic organ formation.

The SHOOT MERISTEMLESS gene is required for maintenance of undifferentiated cells in Arabidopsis shoot and floral meristems and acts at a different regulatory level than the meristem genes WUSCHEL and ZWILLE.

The function of the SHOOT MERISTEMLESS (STM) gene in shoot and floral meristems throughout Arabidopsis development has been analyzed. The results show that STM plays a major role in maintaining shoot and floral meristems. In an allelic series of stm mutants the shoot meristem was either reduced or completely absent in mature embryos and mutant seedling cotyledons showed partial fusion, indicating that the STM gene affects embryonic shoot meristem development and spacing of cotyledons. Postembryonically, stm mutants initiated adventitious shoot development at a position corresponding to the shoot meristem in wild-type. Repetitively initiated defective mutant shoot and floral meristems were consumed during primordia formation and typically terminated prematurely in fused ectopic primordia, indicating that STM is required for continuous shoot and floral meristem function. Analogous defects were observed in stm embryonic and postembryonic development suggesting that similar mechanisms are employed in embryonic and postembryonic organ primordia initiation. Allelic combination suggest different thresholds for STM requirement during plant development. STM requirement could not be bypassed by standard growth factor regimes or by shoot regeneration from calli. The results suggest that STM functions by preventing incorporation of cells in the meristem center into differentiating organ primordia and that this role can completely account for all defects observed in stm mutants. Mutations in the WUSCHEL (WUS) and ZWILLE (ZLL) genes result in defective organization and premature termination of shoot meristems. Genetic interactions between STM, WUS and ZLL were analyzed and the results indicate that STM acts upstream of WUS and ZLL. Therefore, while STM appears to function in keeping central meristem cells undifferentiated, WUS and ZLL seem to be subsequently required for proper function of these cells.