Biomedical subjects

V Vagunda

Publications and source records attributed to V Vagunda.

11 recordsLinked to original sources

PubMed2003

[Apoptosis--selected methods of detection of apoptosis and associated regulatory factors on tissue sections of tumors].

Methods for identification of apoptotic (AP) cells in tissue sections include light and electron microscopy and immunohistochemical (IHC) detection of apoptotic antigens. Bcl-2 at many tumors inversely correlates with AP and is an indirect marker of AP index. Transglutaminase is often expressed in nonapoptotic cells, and thus represents a non specific marker of AP. Likewise, expression of FAS does not necessarily represent a transformation into AP. IHC detection of caspases does not distinguish between active and nonactive forms of the proteases. Immunolabeling of biotin-conjugated Annexin V is used for the identification of phosphatidylserine residues exposed on the surface of AP cells. Annexin V immuno-gold labeling by means of electron microscopy will allow a more refined description of the morphological events occurring during apoptosis. TUNEL, ISEL and ISNTA methods detect DNA breaks. The rate of AP detected by TUNEL is about 20% higher then by apoptotic figure counting. DNA strand breaks can also occur during DNA repair, electrocoagulation, autolysis, fixation and paraffin embedding. With Apostain, DNA is selectively denaturated by heating with formamide and stained by monoclonal antibody specific to single-strand DNA. It specifically stains condensed chromatin of apoptotic cells. M30 IHC uses a monoclonal antibody binding to the product resulting from cleavage of cytokeratin 18 by activated caspases. M30 is negative in necrotic cells and in progressively degraded cells (AP bodies). In contrast to some pilot studies, we have not reached sufficient sensitivity and specificity of IHC detection with M30 (Roche) in breast carcinomas.

Apoptosis↗

PubMed2003

Proliferative activity in primary ovarian carcinoid tumors.

The proliferative potential of six primary ovarian carcinoids with different clinical outcome and histogenetic origin was examined immunohistochemically. The results showed that two cases with extremely high level of proliferative activity were associated with metastatic spread. In the remaining tumors, the examined factor was found to be at low level comparable with excellent prognosis of typical carcinoids in other locations. The preliminary results showed a possibility of a prognosis prediction according to typing of the ovarian carcinoids into two categories, i.e., tumors of low and intermediate malignancy. Topoisomerase II-alpha and Ki-67 are suitable markers giving valuable information about this phenomenon.

Aged↗

PubMed2003

Androgen receptor in prostate carcinoma: immunohistochemical and ligand saturation analyses.

Status of androgen receptor (AR) in prostate carcinoma is biologically important. Therefore, more methods assessing AR abnormalities are warranted. Immunohistochemical (IHC) and ligand saturation (LSA) assays were not compared in details. AR in 53 cases were tested by monoclonal antibody (Ab) F39.4.1 (Biogenex), polyclonal Ab N-20 (Santa Cruz) and by ligand saturation analysis with (3)H-methyltrienolon. Statistical analyses were performed with Spearman's nonparametric rank test including neoadjuvant therapy subgroups treated by antiandrogens, combined androgen blockade (22 cases; flutamide with gosereline) or without therapy. By using monoclonal Ab we found AR positive tumor nuclei in 46 cases. Mean of positives was 64%, median 75%. The polyclonal Ab was not sufficiently specific. With LSA AR were found in 43 cases. Mean level was 6.6 fmol/mg, median 5.5 fmol/mg. Comparing IHC with LSA, we noted correlation trend only for the monoclonal Ab (r=0.35; p=0.02). With thresholds 70% positive nuclei for IHC and 6 fmol/mg for LSA, there were 66% and 43% cases positive with IHC and LSA, respectively. The LSA and IHC positives did not show significant agreement, concordance level being 58% only. We found significant IHC-LSA correlation (r=0.68; p=0.004) solely in combined androgen blockade subgroup with 82% level concordance. Our study has demonstrated that AR IHC and LSA are independent complementary methods. Significant correlation between LSA and IHC show only cases treated with combined androgen blockade. An explanation hypothesis is discussed concerning LH-RH influence on free AR capable of ligand binding. IHC as well as LSA have specific biologic significance and may be useful for prostate cancer diagnostic and therapy.

Adenocarcinoma↗

PubMed2001

Bone marrow micrometastases in patients with stage I-II localised prostate cancer.

Prostate cancer commonly metastasises to the bones. Detection of bone marrow micrometastases (BMM) may give important information that helps define treatment strategies. This study was undertaken to analyse BMM in early prostate cancer patients and to determine the accuracy of immunohistochemical (IHC) and morphological methods in detecting cancerous cells. Preoperative core bone marrow biopsy (BMB) was performed in 103 patients with T1-2, N0, M0 prostate cancer after neoadjuvant androgen blockade. BMB were examined by IHC using monoclonal antibodies for cytokeratins (CK) (18, 19, PAN) and by cytomorphology of IHC-positive cells. In 103 patients, BMM were detected in 2 cases (2%) and an additional 3 cases (3%) were classified as suspicious. IHC alone revealed positive cells in 19 patients (18%). Cytomorphology disclosed IHC false-positive staining of some apparently normal bone marrow elements such as plasmocytes. The study shows a rather low rate of BMM in early prostate cancer. It also stresses the importance of cytomorphology as an adjunct to IHC as IHC alone may not be sufficient and appropriate for BMM detection.

Adult↗

PubMed2000

Correlation between apoptotic figure counting and the TUNEL technique.

OBJECTIVE: To compare histologic detection of apoptotic (AP) figures and terminal transferase UTP nick end labeling (TUNEL) detection in colorectal carcinomas and lymphomas. STUDY DESIGN: We evaluated the percentage of AP cells by AP figure counting and by the TUNEL technique in formalin-paraffin material from 39 tumors--29 colorectal carcinomas and 10 non-Hodgkin's lymphomas. The Lucia G image analysis system (Laboratory Imaging, Prague, Czech Republic) was used for cellularity evaluation and AP counting. RESULTS: On average, 0.81 +/- 0.5% AP cells were detected by figure counting; 0.91 +/- 0.35% were identified by TUNEL. A statistically high correlation between these techniques was found using Pearson's correlation coefficient (r = .56, P < .001). TUNEL, although probably more sensitive, was difficult to standardize. CONCLUSION: AP figure counting seems to be the method of choice for routine work, particularly because of its cost effectiveness and reproducibility.

Apoptosis↗

PubMed1999

p53 status in breast carcinomas revealed by FASAY correlates well with p53 protein accumulation determined by immunohistochemistry.

The prognostic and predictive value of p53 mutation in breast cancer is still conflicting. The choice of the p53 status detection method may account for some discrepancies. In this pilot study we compared two differently-based methods for detection of p53 alteration in 32 breast carcinoma samples: the immunohistochemical method using Bp53, DO1 and DO11 monoclonal antibodies for analysis of the p53 protein accumulation in cell nuclei and the functional method FASAY. FASAY - functional analysis of the separated alleles in yeast - tests the capability of the human p53 to transactivate a reporter with a p53 binding site RGC driving the ADE2 gene in yeast. In our group the percentage of breast cancers with accumulated p53 protein was 50%, as well as percentage of mutant p53 scored by FASAY was 50%. Although the agreement of both methods, when comparing the results of individual patients was high (94%), our results show that immunohistochemistry does not reflect the p53 status quite exactly.

Adult↗

PubMed1998

Early changes in flow cytometric DNA profiles induced by californium-252 neutron brachytherapy in squamocellular carcinomas of the uterine cervix.

Ninety-five squamocellular carcinomas of the uterine cervix, clinical Stages II and III, were treated by either four schedules combining 252-californium neutron-gamma-radiotherapy with different proportions of a neutron component (9, 6 and 3 Gy) or gamma-irradiation alone. Flow cytometric DNA profiles were obtainable in 72 cases before treatment and 56 cases were monitored for DNA content by flow cytometry (FCM) in weekly intervals by analysis of sequential microbiopsies for one month during and after radiotherapy. DNA aneuploidy was reduced from 40% (25/63) to 19% (9/47) one week within therapy in neutron-treated groups, but not after initial gamma-radiotherapy alone. Extinction of DNA aneuploid subpopulations occurred after neutron therapy in all remaining aneuploid tumors (9/9) during further monitoring, but only in 40% (2/5) of tumors after sole gamma-irradiation. In contrast, proliferation index by more than 50% was more often achieved in groups with a higher gamma-radiation component than after neutrons only. When all therapy-induced DNA flow cytometric events are taken together for evaluation of the effects of various radiotherapy schedules, it appears that the regimen with the maximal neutron dose may not be optimal for all tumors. It is hypothesized that the differences in the early flow cytometric DNA profiles may select the DNA aneuploid squamous cell uterine cervical carcinomas as candidates for combined neutron-brachytherapy, while highly proliferating DNA near-diploid tumors may profit more from treatment with a higher gamma-radiotherapy component. However, these early DNA flow cytometric findings need to be correlated with clinical course of the disease to validate this hypothesis, a process which will be completed at the end of the expected five-year clinical outcome in 2000.

Aneuploidy↗

PubMed1998

[An imaging system and computer processing of digital images from the Tesla BS500 transmission electron microscope].

Original digital image acquiring system for electron microscope TESLA BS500 was developed. Optical image from yttriumgarnet monocrystal was captured by TV CCD bottom mounted camera and processed by computer with software Video TIP. Repeated image acquisition enabled substantial improving of signal/noise ratio. Image element of 42 microns diameter was achieved. The system is ready for additional innovation, especially with a high performance CCD camera.

Image Processing, Computer-Assisted↗

PubMed1991

[Routine electron microscopy in the surgical pathology of tumors].

The diagnostic contribution among 35 tumours from Research Institute of Clinical and Experimental Oncology Brno was 62%, 3% of all tumours were examined. The reviewed analogical data are 17-57% and 4-12%. Increased effects is reached by aimed preselection of material. About 5% of all tumours are supposed to be optimal for ultrastructural examination. Broader use of fixation in modified Millonig's solution, especially concerning consultation cases, is recommended.

Humans↗

PubMedDate not supplied

Biomarkers for predicting response to regional chemo-immunotherapy in liver metastases from colorectal carcinoma.

Differences in therapeutic outcomes after regional chemotherapy or chemo-immunotherapy in liver metastases from colorectal carcinoma cannot be explained only by variations in the regimens of treatment. This study was undertaken to assess the potential of several tumor-associated markers of biological behavior (biomarkers) to predict therapeutic response in order to pre-select the best candidates for this demanding treatment. In a group of 21 patients, flow cytometric DNA ploidy provided the most accurate prediction, with a response rate of 88% in 8 DNA diploid tumors compared to 31% in 13 DNA aneuploid cases (P = 0.017) and a difference in overall survival of nine months (20.4 vs 11.3, P = 0.041). Only a slight trend towards improved response rate was observed when we immunohistochemically detected p53 anti-oncoprotein expression in 11 (52%) p53-positive tumors (P = 0.063). Other immunohistochemical biomarkers as P-glycoprotein (p170), p21/WAF, mdm2, c-erbB-2, and proliferative activity of tumor (detected either by anti-PCNA and anti-Ki67 monoclonal antibodies or as a flow cytometric proliferation index) were unrelated to the outcome of treatment. DNA ploidy and expression of p53 protein are potential biomarkers for predicting the response to regional chemotherapy of liver metastases from colorectal carcinoma.

Antineoplastic Agents↗

PubMedDate not supplied

Rare somatic p53 mutation identified in breast cancer: a case report.

Most p53 mutations occur in the central part of the p53 gene that codes for the DNA-binding domain. Missense mutations are prevalent. However, 10-25% of all mutations occur outside exons 5-8 and include a prevalence of frameshift, nonsense and splice site mutations. Functional analysis of p53 transactivation ability in yeast (FASAY) was used to screen for p53 mutations in tumors and a mutant p53 protein retaining partial activity was identified. We characterized this somatic p53 mutation in codon 337: transition C-->T, changing codon CGC to TGC and causing substitution of arginine for cysteine in exon 10, which codes for the tetramerization domain of p53. We detected high accumulation of this mutant p53 protein within the tumor tissue and found that it cannot be immunoprecipitated by either a wild-type p53-specific antibody (PAb1620) or by a mutant p53-specific antibody (PAb240). We confirmed the somatic origin of the mutation by analysis of p53 status in peripheral leukocytes.

Alleles↗