Search results for "Mitosis"
showing 10 items of 156 documents
A pilot study of vinorelbine on a weekly schedule in recurrent and/or metastatic squamous cell carcinoma of the head and neck.
1993
Vinorelbine (VNR), 5′-nor-anhydrovinblastine, is a new semi-synthetic vinka alkaloid with selective affinity for mitotic microtubules, which has been shown to be active against several non small cell lung cancer lines in vitro [1]. VNR has been reported to yield a 34.7 % and 20 % overall response rate in patients with squamous cell lung carcinoma and bronchial adenocarcinoma respectively [2]. Moreover, VNR has been shown to be active in advanced breast carcinoma where it may induce a 30–50 % response rate depending on the extent of pretreatment [3]. We tested the activity and toxicity of single agent VNR given on a weekly schedule in a series of patients with recurrent and/or metastatic squ…
Clinicopathologic and DNA Flow Cytometric Analysis of Eighty-three Renal Cell Carcinomas
1995
The clinical and anatomopathologic features as well as DNA content of 83 renal cell carcinomas were analyzed. The possible interrelationship and prognostic value of these factors were also considered. The DNA study has been performed by flow cytometry using paraffin-embedded tissues. In each case an internal control with nonneoplastic renal tissue obtained in the same nefrectomy was also done in order to calculate the DNA index. Differences in patient age, nuclear grade, and mitotic activity were related with outcome; however, this relationship was not confirmed by the Cox test. Stage (P = .005), cell type (P = .002), and metastatic disease (P = .001) had independent prognostic values. Ren…
Mitotic figure counts are significantly overestimated in resection specimens of invasive breast carcinomas.
2013
Several authors have demonstrated an increased number of mitotic figures in breast cancer resection specimen when compared with biopsy material. This has been ascribed to a sampling artifact where biopsies are (i) either too small to allow formal mitotic figure counting or (ii) not necessarily taken form the proliferating tumor periphery. Herein, we propose a different explanation for this phenomenon. Biopsy and resection material of 52 invasive ductal carcinomas was studied. We counted mitotic figures in 10 representative high power fields and quantified MIB-1 immunohistochemistry by visual estimation, counting and image analysis. We found that mitotic figures were elevated by more than th…
Hemmung der Adenosintriphosphatase durch Colchicin
1951
The ATPase activity is inhibited by Colchicin in concentrations of 10−3 m and 10−4 m at a rate of 40 to 20 %, but in no way in the range of 10−7 m and 10−8 m, where Colchicin exerts its typical spindle-blocking action on the mitotic cell division. It is therefore no evidence, that Colchicin acts by influence on the energy yielding ATP-ATPase system, which was proposed to be responsible for the spindle contraction.
Über die Hemmung von Desoxyribonucleotide spaltenden Fermenten durch Colchicin
1949
The authors raise the question, if enzymatic processes possibly linked with the mitotic cell division may be influenced by mitotic poisons. The presented date show an inhibition of the dephosphorylation of desoxyribonucleotides at a rate of about 50% and of the deamination of about 40% by colchicine (final concentration 1·2·10−2M).
Cell Cycle in Potentially Dedifferentiating Cereal Mesophyll Protoplasts Cultured in vitro II. Behaviour of the Cytoskeleton
1993
Summary Following up on the recent finding that mesophyll protoplasts of wheat and oats were able to reenter the cell cycle when cultured in vitro , the behaviour of the cytoskeleton was studied. The aim was to elucidate whether changes in the cytoskeletal patterns correlate with the abnormal progression through the cycle observed previously. Protoplasts freshly isolated from mature mesophyll tissue (type B) exhibited very few, fragmented microtubules, whereas mesophyll protoplasts isolated from immature leaf tissue (type A) showed an abundant network fo microtubules. Type B protoplasts of wheat, which were able to reenter but recalcitrant to complete S-phase, failed to reestablish a microt…
“Mitotic Slippage” and Extranuclear DNA in Cancer Chemoresistance: A Focus on Telomeres
2020
Mitotic slippage (MS), the incomplete mitosis that results in a doubled genome in interphase, is a typical response of TP53-mutant tumors resistant to genotoxic therapy. These polyploidized cells display premature senescence and sort the damaged DNA into the cytoplasm. In this study, we explored MS in the MDA-MB-231 cell line treated with doxorubicin (DOX). We found selective release into the cytoplasm of telomere fragments enriched in telomerase reverse transcriptase (hTERT), telomere capping protein TRF2, and DNA double-strand breaks marked by γH2AX, in association with ubiquitin-binding protein SQSTM1/p62. This occurs along with the alternative lengthening of telomeres (ALT) and DNA repa…
Poriferan survivin exhibits a conserved regulatory role in the interconnected pathways of cell cycle and apoptosis
2010
Survivin orchestrates intracellular pathways during cell division and apoptosis. Its central function as mitotic regulator and inhibitor of cell death has major implications for tumor cell proliferation. Analyses in early-branching Metazoa so far propose an exclusive role of survivin as a chromosomal passenger protein, whereas only later during evolution a complementary antiapoptotic function might have arisen, concurrent with increased organismal complexity. To lift the veil on the ancestral function(s) of this key regulator, a survivin-like protein (SURVL) of one of the earliest-branching metazoan taxa was identified and functionally characterized. SURVL of the sponge Suberites domuncula …
Variability of ecdysteroid-induced cell cycle alterations in Drosophila Kc sublines.
1987
. The cell cycle of two lines isolated from Drosophila Kc cells was followed by flow cytofluorometry and cell counting. The first line is the 8-9K clone which grew in a medium supplemented with 5% serum; the second, named subline Kc0, grew in a serum-free medium. The stationary phase is characterized by a G2 cell accumulation: 73% in the 8-9K clone and 50% in the Kc0 subline. When the medium was supplemented with the steroid moulting hormone 20-hydroxyecdysone, more than 90% of 8-9K cells and 65% of Kc0 cells were progressively arrested in G2. In the continuous presence of 20-hydroxyecdysone, most of the 8-9K cells remain G2-arrested; no massive G2 release into M was observed and only a few…
Synthesis of a new class of pyrrolo[3,4-h]quinazolines with antimitotic activity
2014
Abstract A new series of pyrrolo[3,4- h ]quinazolines was conveniently prepared with a broad substitution pattern. A large number of derivatives was obtained and the cellular cytotoxicity was evaluated in vitro against 5 different human tumor cell lines with GI 50 values reaching the low micromolar level (1.3–19.8 μM). These compounds were able to induce cell death mainly by apoptosis through a mitochondrial dependent pathway. Selected compounds showed antimitotic activity and a reduction of tubulin polymerization in a concentration-dependent manner. Moreover, they showed anti-angiogenic properties since reduced in vitro endothelial cell migration and disrupted HUVEC capillary-like tube net…