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Biomedical subjects

M Kawecki

Publications and source records attributed to M Kawecki.

At least 19 recordsLinked to original sources
PubMed1998

Selective inhibition of prolactin gene transcription by the ETS-2 repressor factor.

Regulation of prolactin gene transcription requires cooperative interactions between the pituitary-specific POU domain protein Pit-1 and members of the ETS transcription factor family. We demonstrate here that the ETS-2 repressor factor (ERF) is expressed in pituitary tumor cells and that overexpression of recombinant ERF inhibits prolactin promoter activity, but not the closely related growth hormone promoter. In non-pituitary cell lines, coexpression of ERF disrupts the cooperative interactions between Pit-1 and ETS-1 and blocks the induction of Pit-1-dependent prolactin promoter activity by cAMP. The potential role of ERF in the inhibitory response of the prolactin promoter to dopamine was examined using pituitary tumor cells stably expressing dopamine D2 receptors. The inhibitory responses of the prolactin promoter to ERF and dopamine are additive, suggesting that ERF has a complementary role in this hormonal response. A single Pit-1 DNA-binding element from the prolactin promoter is sufficient to reconstitute the inhibitory response to ERF. DNA binding analysis using either a composite Pit-1/ETS protein-binding site or a Pit-1 element with no known affinity for ETS proteins revealed that ERF interferes with Pit-1 binding. Together, these results demonstrate that ERF is a specific inhibitor of basal and hormone-regulated transcription of the prolactin gene and suggest a new level of complexity for the interaction of ETS factors with Pit-1 target genes.

Animals↗
PubMed1998

Dual-function reporter protein for analysis of gene expression in living cells.

The firefly luciferase (Luc) protein and the jellyfish green fluorescent protein (GFP) are two commonly used molecular reporters that can be detected noninvasively in living cells. The properties that make GFP or Luc useful for a particular experimental application are quite distinct. A recombinant protein with both fluorescent and bioluminescent characteristics might take advantage of the strengths of both reporters. An expression vector encoding a chimeric protein in which GFP was tethered to Luc through a 19-amino acid linker was prepared and characterized. Western blotting with antibodies specific for either GFP or Luc showed that a protein of appropriate size was expressed in transfected cells. Fluorescence microscopy revealed bright green fluorescence from transfected cells, indicating proper formation of the GFP chromophore. Luc enzymatic activity in protein extracts from transfected cells showed that Luc was fully functional. The treatment of living cell cultures stably expressing the GFP-Luc fusion protein with the protein translation-inhibitor cycloheximide (Chx) was used to show that the half-life for Luc protein activity was approximately 2 h at 37 degrees C. The utility of this dual-function reporter protein was shown by the identification of single living cells expressing the chimeric protein within a population by fluorescence microscopy, followed by quantification of Luc activity from the same living cells.

Cell Line↗
PubMed1997

[Rectal cancer in clinical material. Effect of advanced clinical staging, tumor location and type of surgical treatment on long term results].

The aim of the research is presentation of patients' material, operated on in The Clinic in the years 1965-1993 because of rectal cancer. The material makes 1363 patients, where group of 214 patients was separated from, treated in the years 1989-1993, basing on modern system of medical examinations qualifying for the surgical intervention and included by intensive prospecting monitoring. At investigative periods 1965-1989 and 1989-1993 the transition of rectal Dukes' stages on A and B interest was noticed, this admitted to increase the whole number of local excision et anterior rectum resection and improve distant treatment results, five years' survival measured. Percentage of patients with inoperable clinical staging, at periods: 1965-1989 and 1989-1993, is similar, in spite of considerable development of diagnostic methods.

Follow-Up Studies↗
PubMed1997

[Inflammatory tumors of the colon--diagnostic and therapeutic problem in clinical materials].

38 patients with inflammatory tumours of the large bowel (ITLB) were studied, it is 2.4% of all patients operated in our department for the large bowel tumours. 28 patients (73.7%) underwent elective surgery, 10 (26.3%) had emergency operations. One-stage operations were performed in 26 cases (68.4%) and two-stages operations in 12 (31.6%). Permanent colostomies were performed in 4 patients (10.5%). Histological examination indicated chronic colitis in 19 cases (50.0%), mostly on divercular disease basis, Crohn's disease in 7 (18.4%), profound ulcerative colitis in 5 (13.1%), actinomycosis in 3 (7.9%) and typhlitis in 2 (5.3%).

Actinomycosis↗