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R Miturski

Publications and source records attributed to R Miturski.

At least 19 recordsLinked to original sources
PubMed2002

Evaluation of DNA mismatch repair system in cervical dysplasias and invasive carcinomas related to HPV infection.

UNLABELLED: The aim of this study was to answer the question whether the products of hMSH2 and hMLH1 genes take part in the mutation track of cervical carcinoma. METHODS: IgG1 monoclonal antibodies (Pharmingen) detecting epitopes characteristic of hMLH1 and hMSH2 were used in the present study. The value of the half-quantitative H-score coefficient was calculated. Its threshold value was 0.4. Identification of 16 and 18 HPV types was performed by PCR. RESULTS: An intensified hMLH1 protein expression was observed both in the squamous epithelial carcinomas and cervical adenocarcinomas (H-score of 1.44 and 0.98, respectively) as compared to the control (H-score of 0.9). However, a decreased expression of hMSH2 protein was observed in the analysed cases of carcinoma (0.9 and 0.7) as compared to the control group (1.2). An intensified expression in G3 for hMLH1 and higher hMLH1 in comparison to hMSH2 was observed. CONCLUSIONS: 1. A considerable expression of hMLH1 and hMLH1 proteins was observed in the tissues with invasive cervical carcinoma not only within epithelial but also in stromal cells. 2. More intense expression of hMLH1 and hMSH2 was observed in invasive carcinomas and CIN than in the non-neoplastic cervical tissue lesions (erosion). 3. A stronger expression was observed for the hMLH1 than for the hMSH2 proteins--contrary to the cases of carcinomas of the uterine corpus and endometrial carcinoma.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Early detection of 2-amino-1-methyl-6-phenylimidazo (4,5-b)pyridine(PhIP)-induced mutations within the Apc gene of rat colon.

A large proportion of human cancers result from exposure of individuals to environmental or occupational carcinogens. The early detection of carcinogen-induced mutations is a prerequisite for the identification of individuals at risk for developing cancer. Short G-rich repetitive sequences have been previously identified as hot-spots for frameshift mutagenesis induced by a large variety of carcinogens belonging to several families of widespread environmental pollutants. In order to test if these sequences, when mutated, might serve as biomarkers for carcinogen exposure, we designed a sensitive PCR-based strategy that allows the detection of rare mutational events within a whole genome. 2-Amino-1-methyl-6-phenylimidazo(4,5-b)pyridine (PhIP), the most abundant carcinogenic heterocyclic amine generated in cooked meat, induces mammary and colon carcinoma in F344 rats. About 25% of male rats exposed to 400 p.p.m. PhIP in the diet for >43 weeks present colon tumors with specific -1G mutations within 5'-GGGA-3' sequences of the APC: gene. Using our PCR assay we have assessed the occurrence of such specific events in rats exposed to PhIP for only 1, 2, 4 and 6 weeks. A specific amplification signal was already observed in the 1 week-treated population and increases in a treatment time-dependent manner. These data validate this approach for the early detection of mutations and demonstrate its usefulness for molecular epidemiology and early diagnosis.

Animals↗
PubMed2001

Molecular mechanisms of retinoid action.

In the past few years our understanding of nuclear receptor (NR) action has been dramatically improved. This is due to to advancements in three fields, (i) 3D structure determination, (ii) analysis of the complexes formed between nuclear receptors and co-regulatory molecules, and (iii) the genetic analysis of nuclear receptor signalling by gene "knock out" and "knock in" technologies. The elucidation of the crystal structure of apo-, holo (agonist)- and antagonist-NR ligand-binding domain (LBD) complexes is of outstanding importance for our understanding of the structural principles, in particular of the ligand-induced allosteric alterations, that are at the basis of receptor action. The concomitant identification and functional analysis of co-regulators (TIFs, coactivators and co-repressors) previously predicted from squelching studies have provided the possibility to understand the propagation of the original signal from ligand binding through intramolecular allosteric effects to intermolecular interactions. Recent crystal data of receptor LBD heterodimers and LBD-agonist complexes with nuclear receptor interacting peptides of co-activators have provided molecular insights into receptor dimerization and receptor-coactivator interaction. Finally, analysis of the signalling compexes established over nuclear receptors, assembling enzymatic activities that can alter the acetylation status of chromatin at the promoter regions of target genes and (de)acetylate other transcription regulatory factors paves the way to a comprehension of receptor action at the chromatin level. But much remains to be learnt and the recent studies have pointed towards an enormous complexity of this signalling system. Insights into the mechanistic basis of promyelocytic leukemia and the role of retinoic acid in differentiation therapy have been obtained as a consequence of the above studies, justified the efforts and led to an increasing awareness of the nuclear receptor signalling systems in basic and applied research. Here we will review recent data with the focus on what we have learnt about the interplay between NR structure and function to provide a view of the early steps of nuclear receptor action.

Animals↗
PubMed2001

[Assessment of the PCNA and P53 proteins expression in the proliferative, hyperplastic and neoplastic human endometrium].

In the current study, PCNA and p53 proteins were immunohistochemically studied in the proliferative (n = 5), hyperplastic (n = 4) and neoplastic (n = 20) human endometrium. PCNA immunostaining was noted in 2 out of 5 (40%) proliferative, 4 out of 4 (100%) hyperplastic, and in 18 out of 20 (90%) neoplastic slides. Concomitant PCNA and p53 expression was reported in 12 out of 20 (60%) malignant tumors. All non-endometrioid neoplasms were PCNA-positive, suggested this proliferative marker is commonly expressed in the unfavorable histological types of endometrial cancer.

Adult↗
PubMed2000

RB protein expression in human endometrial carcinomas--an immunohistochemical study.

The aim of the current study was to investigate the immunohistochemical expression of the retinoblastoma protein (pRB) in formalin-fixed, paraffin-embedded specimens obtained from 62 patients suffering from endometrial cancer. The avidin-biotin-peroxidase detection system with microwave pretreatment and the mouse anti-human NCL-RB1 monoclonal antibody were used. Heterogeneous nuclear immunostaining for the pRB was generally observed in the glandular cells in 59 out of 62 (95%) endometrial carcinomas, while stromal components were unreactive. In one case of stage Ic endometrioid adenocarcinoma, a small percentage of glandular cells (5%) stained positively with the anti-RB antibody, while two other tumors (stage IIa adenosquamous carcinoma and stage IIIa endometrioid adenocarcinoma) were pRB negative. In the cases with concomitant hyperplastic and neoplastic endometrial lesions, pRB immunoreaction was heterogeneous in the hyperplastic endometrial cells and in the adjacent neoplastic endometrium. Moreover, eight cases of endometrial carcinoma harboring K-ras codon 12 gene point mutation overexpressed pRB (more than 80% of glandular endometrial cells were positive) immunohistochemically, while none of three pRB negative slides had a K-ras gene alteration. Our data support the view that the pRB is expressed in most of the human endometrial neoplasms, but the lack of pRB immunoreactivity may correspond with the retinoblastoma gene rearrangements in a subset of advanced endometrial carcinomas.

Adenocarcinoma↗
PubMed2000

Molecular approach in cancer epidemiology: early detection of carcinogen-induced mutations in a whole genome (Review).

Chronic exposure of organisms to endo- or exogenous genotoxic products results in the accumulation of mutations in the genome and eventually to the development of cancers. Early detection of these mutations would allow the identification of at risk individuals who present a high load of mutations either because of an occupational or environmental exposure, or because of less efficient DNA repair processes. However, highly specific and sensitive assays are required to allow the detection of point mutations in a whole genome. We review a long-term study on the mutagenesis induced in E.coli by an aromatic amide, the N-2-acetylaminofluorene. A major contribution of this work was to reveal the presence of specific mutation hot spot sequences. Taking advantage of this observation, we designed a specific, sensitive and semi-quantitative in vitro assay allowing the detection of carcinogen induced mutations. This assay has been validated in vivo and demonstrate the sensitivity of the technique in early detection of mutations and its usefullness in molecular epidemiology, early diagnostic and prognosis.

2-Acetylaminofluorene↗
PubMed2000

Relationship between HPV infection of the cervix and blood serum levels of steroid hormones among pre- and postmenopausal women.

Human papillomaviruses (HPVs) are frequently present in anogenital lesions but little is known about their role in carcinogenesis. There are steroid hormone response elements in virus genomes that influence expression patterns of viral genes. Activity of the elements may contribute to development of neoplasia in case of hormone level anomalies. Our study was to determine whether the presence of HPV DNA in cervical smears correlates with abnormal levels, of steroid hormones in blood serum. One hundred women aged 40-62 participated in the tests and were divided into two groups: premenopausal and postmenopausal (45 and 55 individuals, respectively). Presence of HPV DNA in cervical smears was detected by PCR and Southern blot hybridisation. Progesterone and estradiol levels in blood serum were measured by radioimmunoassay. Our study showed a higher prevalence of HPV DNA in women with higher levels of progesterone in blood serum. A relationship between hormone level and HPV DNA prevalence should alert clinicians about using hormone contraceptives and hormone replacement therapy.

Adult↗
PubMed1999

Sequence context modulation of translesion synthesis at a single N-2-acetylaminofluorene adduct located within a mutation hot spot.

Oligonucleotides containing a single N-(deoxyguanosin-8-yl)acetylaminofluorene lesion (dGuo-C8-AAF) at each guanine residue of the sequence (5'-G1G2G3) have been used as templates for in vitro primer extension reactions by several DNA polymerases [Escherichia coli DNA polymerase III holoenzyme, its alpha subunit, DNA polymerase I Klenow fragment proficient (exo+) or deficient (exo-) in its 3' --> 5' exonuclease activity, and Sequenase]. The dGuo-C8-AAF lesion appears to be a strong block for all DNA polymerases: exo+ DNA polymerases stop one nucleotide before encountering the lesion, while partial incorporation opposite the lesion is observed only with enzymes devoid of the exonuclease activity. The efficiency of incorporation across from the adduct depends on both the DNA polymerase and the position of the lesion. When polymerase I Klenow fragment exo- is used, translesion synthesis (TLS) is observed with efficiencies varying according to the position of the adduct (G2 > G1 > G3). Sequencing of the TLS products shows that error-free TLS is observed only when the AAF lesion is bound to G1, while all TLS events occurring at G2- or G3-AAF adducts are mutagenic. The major mutational event is a G deletion (27, 76, and 55% of the events for G1, G2, and G3, respectively), while two-G deletions occur to a lesser extent (17-30%). These results are discussed in view of the slippage model developed for frameshift mutagenesis occurring during translesion synthesis at replication blocking lesions.

2-Acetylaminofluorene↗
PubMed1999

Concentration of an epidermal growth factor in blood serum of males during topical treatment of psoriasis.

Epidermal growth factor (EGF) is a mitogen that stimulates cell division of various cells of epidermal origin. The present study was undertaken to clarify whether the serum level of EGF is correlated with the disease activity during local therapy with dithranol in psoriasis. We examined serum EGF concentrations in acute and chronic psoriasis before and after topical treatment with dithranol and the correlation with Psoriasis Activity and Severity Index (PASI). Male patients were divided into two groups: acute psoriasis (AP, 18 cases) and chronic psoriasis (CP, 17 cases). A control group C consisted of 20 healthy male volunteers. Radioimmunoassay of EGF was performed using the reagent pack (Amersham, UK). In the CP group mean EGF was higher before treatment than in the AP and C groups, but not significantly. EGF concentration after local treatment was higher in the CP group than the AP group (P < 0.02); the AP group, however, showed statistically significant decrease of EGF after the treatment (P < 0.04). No correlation between EGF and PASI was found. Serum EGF concentration increased in 19/35 treated patients.

Acute Disease↗
PubMed1999

Analysis of p53 and K-ras genes and their proteins in a sarcoma botryoides of the uterine cervix.

Several data indicate that the activation of oncogenes and growth factors as well as inactivation of the tumor suppressor genes are implicated in the development of human neoplasms, including sarcomas. In the present study we described a case of the extremely rare, but highly malignant neoplasm of the female genital tract known as sarcoma botryoides of the uterine cervix and assessed, using molecular and an immunohistochemical analysis, p53 and K-ras alterations in the tumor. A point mutation in exon 6 of the p53 tumor suppressor gene was found but no K-ras gene point mutations at codons 12, 13 and 61 were detected using molecular analysis. p53 protein was overexpressed in more than half of the neoplastic cells, however, ras p21 protein expression was not immunohistochemically detected. Our data indicate that p53, but not K-ras gene alterations may play a role in the development and progression of sarcoma botryoides of the uterine cervix.

Adolescent↗
PubMed1998

bcl-2 protein expression in endometrial carcinoma: the lack of correlation with p53.

bcl-2 expression was examined on paraffin-embedded specimens in proliferative, hyperplastic, and neoplastic human endometrium by immunohistochemistry. The results of bcl-2 immunostaining in endometrial carcinomas were compared with clinicopathological indicators as well as with p53 accumulation. The streptavidin-peroxidase detection system was used and the intensity and the distribution of immunostaining was evaluated semiquantitatively by counting H-score values. Expression of the bcl-2 protein was found in 2 out of 5 cases of proliferative endometrium (mean H-score 0.4, range 0.35-0.45), 4 out of 5 cases of simple hyperplasia (mean H-score 1.23; range 1.0-1.4), 4 out of 5 cases of complex hyperplasia (mean H-score 1.1; range 0.7-1.2) and in 7 out of 25 cases of endometrial carcinoma (mean H-score 0.48; range 0.35-0.65). All bcl-2 positive slides were obtained from patients who had endometrial cancer and who were in the early (stage I due to FIGO) clinical stage of the disease. bcl-2 expression was not related to age, surgical stage or histopathological features, and neither was there an inverse correlation between bcl-2 immunostaining and p53 expression reported in the study of neoplastic endometrium. Our data indicate that mechanisms other than p53 may play a role in the regulation of bcl-2 expression in endometrial carcinomas.

Aged↗
PubMed1998

Immunohistochemical expression of syndecan-1 in human endometrial cancer cells.

There are indications of increased frequency of endometrial cancer, one of the most common malignancies in women. Tissue samples of normal and malignant endometria were obtained post operatively from 30 women. We noted expression of syndecan-1 in 40% of investigated cancers. The most differentiated cancers showed 75% of positively stained specimens, moderately differentiated 40% and poorly differentiated neoplasm did not stain at all. In normal endometrial tissue syndecan-1 expression was regular and distinct in each specimen, but immunoreactivity of the hyperplastic endometrial specimens was absent. The detection of syndecan-1 in endometrial cancer of different clinical and histological stages could be of prognostic value in clinical diagnosis.

Aged↗
PubMed1998

Expression of ras p21 in the stromal cells of human neoplastic endometrium.

ras p21 proteins have been reported to take part in signal transduction through a cell membrane to the nucleus and they also play a crucial role in the process of carcinogenesis. Forty specimens of neoplastic endometrium, ten slides of normal endometrium and one case of uterine carcinosarcoma were investigated for ras p21 expression in the stromal cells by immunohistochemistry. Stromal cells expressed ras p21 protein in 13 out of 40 (33%) cases of neoplastic endometrium. These cells were randomly dispersed wound the glandular crypts of the endometrium and were also detected in the adjacent myometrium surrounding the cancer tissue. When cancers were grouped by surgical stage, ras p21 protein was detected in 11/22 (50%) of stage I, but only in 2/18 (11%) of stages II-IV according to FIGO. None of the stromal cells immunostained for p21 in normal endometrium or myometrium, however, a single case of carcinosarcoma expressed ras p21 within the stromal cells.

Aged↗
PubMed1998

[Tissue zearalenone concentration in normal, hyperplastic and neoplastic human endometrium].

Zearalenone (ZEA), a nonsteroidal mycotoxin with estrogen-like activity, is synthesized by molds (Fusarium) commonly contaminating poorly stored agricultural products and foodstuffs. Human ER binds ZEA and this is probable mechanism of its action, although their influence on target tissues seems to be weaker (80-160 less active) comparing to E2. Zea has been observed to possess tumor-promoting activity similar to that of estrogens and hypothetically can inducing proliferation and carcinogenesis in estrogen-dependent tissues. Nowadays, the questions are, if ZEA is present in human endometrium and whether concentrations of this mycoestrogen is associated with endometrial cell proliferation. Endometrial tissues specimens were collected from 49 women (endometrial adenocarcinoma n = 27, endometrial hyperplasia n = 11, normal proliferative endometrium n = 11). Mean tissue zearalenone concentration in 3 endometrial hyperplasia and 22 adenocarcinoma samples was 47.8 +/- +/- 6.48 and 167 +/- +/- 17.69 ng/ml respectively in contrary to normal endometrium where tissue mycoestrogen concentration was not detectable. In 8 cases of hyperplastic and 5 cases of neoplastic endometrial tissue specimens ZEA was not observed. Our findings confirm the presence of ZEA in hyperplastic and neoplastic endometrium and therefore this substance might be of importance in carcinogenesis.

Adenocarcinoma↗
PubMed1997

ras p21 immunohistochemical detection in human endometrial carcinomas.

Tissue samples of 40 patients with histologically confirmed endometrial cancer were analyzed immunohistochemically on paraffin-embedded specimens to detect ras p21 protein expression. The relationship between p21 protein expression and clinicopathological findings was also analyzed. The intensity and distribution of specific cytoplasmatic staining were evaluated semiquantitatively by counting the immunohistochemical H-score. ras p21 expression was found in 30 (75%) of 40 human endometrial carcinomas, regardless of the clinical stage of the disease. Positive immunostaining for p21 was noted in 68% of stage I-II and in all 8 of the advanced stages (III-IV according to FIGO) of endometrial carcinomas. Myometrial invasion was related to ras p21 immunostaining (p = 0.009), however, no correlation between histological findings and ras p21 expression was observed.

Adenocarcinoma↗
PubMed1996

Simultaneous expression of the ras p21 and p53 proteins in human endometrial carcinomas.

The expression of ras-encoded p21 and p53 proteins was analyzed by immunohistochemical staining with monoclonal antibodies in 26 paraffin-embedded specimens (25 endometrial carcinomas and 1 uterine carcinosarcoma) taken from Polish women. The biotin-streptavidin-peroxidase detection system was employed. ras p21 protein was expressed in 68% of the specimens and p53 positive staining was noted in 36% of the carcinomas. Simultaneous expression of the ras p21 and p53 proteins was demonstrated in 8 (32%) out of the 25 specimens. Except one case, where the p53 protein was expressed, ras p21 protein was also detected. Both proteins were demonstrated in the sole case of carcinosarcoma. A difference between the detection of simultaneous expression of the ras p21 and p53 proteins in correlation with FIGO stages I to II-IV has been reported (22% v. 57% respectively). These data indicate, that ras p21 correlated with p53 positive staining in one-third of the endometrial cancers analyzed. The simultaneous detection of both proteins correlated with the advanced clinical stage of human endometrial carcinomas.

Aged↗