Über den Unterschied zwischen Phasen- und Signalgeschwindigkeit bei der Bestimmung der Wellenlänge stehender Schlauchwellen

Ohne Zusammenfassung     

The tension-free vaginal tape operation for the treatment of stress incontinence

The tension-free vaginal tape (TVT) operation and similar procedures are the newest development in the surgical treatment of female stress incontinence. In contrast to the Burch colposuspension and abdominovaginal sling procedures, the operation aims at supporting the midurethra and not the bladder neck. The only ongoing prospective randomized trial comparing TVT with the Burch colposuspension, conducted by the UK and Ireland TVT Trial Group, shows comparable 2-year results. The TVT operation is a technically simple procedure with a low rate intraoperative and postoperative complications. This and the good cure rates may make this procedure and similar methods the standard operation for the treatment of primary and recurrent stress incontinence.     

Percutaneous embolization in the management of intractable vaginal bleeding

AIM: To assess the effectiveness of arterial embolization in gynecological malignancies by Polyvinyl Alcohol particles. MATERIAL AND METHODS: Six patients, four with cervix carcinoma, one endometrium carcinoma, and one vaginal metastasis of ovarian carcinoma underwent percutaneous embolization due to intractable vaginal bleeding. As an embolic agent PVA particles were used. RESULTS: Cessation of the bleeding was observed immediately after the embolization. Complete embolization has been achieved in all the patients Recurrent bleeding did not occur in any of the cases. There were no complications related to the embolization procedure. CONCLUSION: Transarterial embolization is a lifesaving procedure in treating intractable vaginal bleeding. PVA particles are effective and it is a simple way in ceasing the hemorrhage due to pelvic malignancies.     

Anticancer drug-mediated induction of multidrug resistance-associated genes and protein kinase C isozymes in the T-lymphoblastoid cell line CCRF-CEM and in blasts from patients with acute lymphoblastic leukemias.

The major determinants mediating drug resistance in acute lymphoblastic leukemias (ALL) unresponsive to chemotherapy, are still unclear. For example, it is still unknown whether selection or induction processes are responsible for drug resistance here or whether protein kinase C (PKC) isozymes contribute to the resistant phenotype. Therefore, inducibility of resistance factors or PKC isozymes genes was examined in CCRF-CEM cells treated with diverse anticancer drugs--adriamycin, camptothecin, etoposide or vincristine--at sublethal concentrations for 24 h. MDR1, MRP1, LRP and PKC isozyme alpha, beta(1), beta(2), epsilon, iota, eta, theta, zeta gene expression was determined by cDNA-PCR. We found significant dose-dependent, mostly combined, induction of the MDR1, MRP1 and LRP genes. Significantly enhanced gene expression of the majority of PKC isozyme genes was found after treatment with camptothecin. PKCzeta was upregulated throughout by each anticancer drug applied in this setting. A series of selected CCRF-CEM-derived multidrug resistance (MDR) sublines also showed enhanced expression of the PKC isozymes compared to the parental cell line. MDR1 and PKCeta gene expression levels were correlated highly significantly. Blasts from two patients with ALL during the first week of monotherapy with steroids revealed combined induction of the MDR1, multidrug resistance-associated protein 1 (MRP1), lung cancer resistance-related protein (LRP) and most PKC isozymes, predominantly PKCzeta. Another patient with T-ALL, who failed to respond to four months of intensive chemotherapy, showed an enhanced MRP1 gene expression combined with markedly overexpression of PKCeta and PKCtheta. Furthermore, the camptothecin and etoposide-mediated induction of resistance factors in the CCRF-CEM cell line could be suppressed by staurosporine, a rather unspecific inhibitor of protein kinases. However, selective inhibitors of PKC isozymes (bisindolylmaleimide GO 6850, indolocarbazole GO 6976) produced no significant effects here. Therefore, the PKC isozymes eta, theta and zeta are of interest as potential targets to overcome drug resistance in ALL.     

Natural product-based anti-HIV drug discovery and development facilitated by the NCI developmental therapeutics program.

During the decade 1987-1996, the Developmental Therapeutics Program (DTP) of the National Cancer Institute (NCI) provided infrastructure support for both intramural and extramural anti-HIV (human immunodeficiency virus) drug discovery research and development. This retrospective review describes some of the anti-HIV lead discovery and development that took place under DTP auspices or which was substantially facilitated by resources made available through the DTP. Examples highlighted include leads identified through the initial screening of pure natural product derived compounds and those derived from bioassay-guided fractionation of crude natural product extracts, and these are classified according to the mechanism of action targeting the critical steps within the replication cycle of HIV.     

Stilbene analogues affect cell cycle progression and apoptosis independently of each other in an MCF-7 array of clones with distinct genetic and chemoresistant backgrounds

The development of chemoresistant breast cancer is poorly understood and second treatment options are barely investigated. The term 'chemoresistance' is ill-defined and thus, our experimental analyses aimed to disentangle the resistance to cell cycle arrest from the resistance to trigger apoptosis, both of which are important mechanisms to be targeted by anticancer therapy. Therefore, an MCF-7 array, which encompassed clones harboring distinct genetically- and pharmacologically-induced stages of resistance, was established. For this, MCF-7 cells were stably transfected with erbB2 cDNA and a dominant negative p53 mutation and the two clones were subjected to long-term treatment with the clinical agents 2'-deoxy-5-fluorouridine (5-FdUrd) or arabinosylcytosine (AraC) to develop specific chemoresistance. This array was tested with 3,4',5-trihydroxy-trans-stilbene (resveratrol) and the methoxylated paired stilbene analogue 3,4',5-trimethoxy-trans-stilbene (M5) to investigate whether these agents can overcome genetically- and pharmacologically-induced chemoresistance and to correlate the structure-activity relationship of resveratrol and M5. In all conditions tested, M5 exhibited stronger anticancer activity than resveratrol, but the cell cycle inhibitory properties of the tested drugs were dependent on the genetic background and the chemoresistant phenotype. In contrast, the proapoptotic properties were rather similar in the distinct genetic backgrounds of the clone array and therefore, apoptotic triggers and cell cycle checkpoints were distinctly affected and are thus independent of each other. The study demonstrates the merits or virtues of the genotypically- and phenotypically-defined clones of the MCF-7 array as a testing tool for novel drugs, which discriminates the two types of chemoresistance mechanisms.