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Biomedical subjects

E Protopapa

Publications and source records attributed to E Protopapa.

13 recordsLinked to original sources
PubMed2006

Electrochemical screening of self-assembling beta-sheet peptides using supported phospholipid monolayers.

In the context of the medical applications of beta-sheet self-assembling peptides, it is important to be able to predict their activity at the biological membrane level. A study of the interaction of four systematically varied 11-residue (P11-1, P11-2, P11-6 and P11-7) and one 13-residue (P13-1) designed beta-sheet self-assembling peptides with DOPC monolayers on a mercury electrode is reported in this paper. Experiments were carried out in 0.1 mol dm(-3) KCl electrolyte with added phosphate buffer (0.001 mol dm(-3)) at pH approximately 7.6. The capacity-potential curves of the coated electrode in the presence and absence of the different peptides were measured using out-of-phase ac voltammetry. The frequency dependence of the complex impedance of the coated electrode surfaces in the presence and absence of the peptides was estimated between 65,000 and 0.1 Hz at -0.4V versus Ag/AgCl 3.5 mol(-3) dm(-3) KCl. The monolayer permeabilising properties of the peptides were studied by following the reduction of Tl(I) to Tl(Hg) at the coated electrode. Of the five peptides studied, P11-2, P11-7 and P13-1 interact most strongly with the DOPC layer. P11-1 which has a polar primary structure shows no obvious interaction with the phospholipid but surprisingly, it permeabilises the phospholipid layer to Tl(+).

Adsorption↗
PubMed2000

Image analysis of mesothelioma. I. differentiation of mesothelioma from adenocarcinoma of the lung.

OBJECTIVE: To explore the usefulness of nuclear micromorphometric analysis for the differentiation between epithelial mesothelioma and metastatic adenocarcinoma in the chest wall. STUDY DESIGN: High-resolution images of 2,100 nuclei from 27 cases of epithelial mesothelioma and 15 cases of adenocarcinoma of the lung were recorded. Stepwise discriminant analysis and a nonparametric classifier were applied to derive estimates for a case diagnosis correct classification rate. RESULTS: Nuclei from epithelial mesothelioma and adenocarcinoma of the lung showed statistically significantly different properties, but there was a region of overlap in feature space such that approximately 15-20% of cases could not be correctly classified. The lesion signatures derived from the mesothelioma cases with discriminant function scores that might result in case misclassification and the cases of adenocarcinoma of the lung spanned a similar range of degree of nuclear abnormality. However, the distribution of nuclear abnormality values for the mesothelioma cases has a mode at 0.87 SD from normal, whereas the distribution seen in lung adenocarcinoma cases had a mode at about 3.7 SD. CONCLUSION: Cases of epithelial mesothelioma and adenocarcinoma of the lung have nuclei with a wide range of deviation from normal in the spatial and statistical distribution of their nuclear chromatin. For approximately 80% of cases, correct case classification can be provided by nuclear micromorphometric analysis. Cases of epithelial mesothelioma with highly abnormal nuclei overlap in feature space with nuclei from adenocarcinoma of the lung. However, it is possible that characterization by a lesion signature may allow correct assignment for those cases.

Adenocarcinoma↗
PubMed2000

Image analysis of mesothelioma. II. Discrimination of mesothelioma from metastatic serous ovarian adenocarcinoma.

OBJECTIVE: To examine the utility of karyometric measurements in the differentiation of mesothelioma from metastatic serous ovarian adenocarcinoma. STUDY DESIGN: High-resolution images of 1,631 nuclei from 32 cases of mesothelioma and 742 nuclei from 15 cases of ovarian adenocarcinoma were recorded. A stepwise discriminant analysis and nonparametric classifier were applied. RESULTS: Nuclei from these two diagnostic categories appear very similar and occupy feature space with significant overlap. A nonparametric classification procedure provided acceptable correct classification. CONCLUSION: For certain regions in feature space, cases could be unequivocally classified.

Cell Nucleus↗
PubMed1997

Quantitative pathology in uterine smooth muscle tumours: the case for the standard histologic classification criteria.

A number of nuclear morphometric factors (longest and shortest axis, perimeter, area, roundness coefficient) as well as the number of mitoses per 20 high power fields with an x40 objective (mitotic index) and the volume corrected mitotic index (VCMI) have been assessed in 33 uterine smooth muscle tumours (14 leiomyomata, 5 leiomyosarcomata, 9 atypical leiomyomata and 5 tumours of uncertain malignant potential). Multivariate analysis showed the VCMI and nuclear roundness coefficient to be the two most significant prognostic factors achieving, by means of Fisher's linear discriminant function, a high percentage of correct reclassification of the tumours into their respective groups. Furthermore, VCMI was shown to be a more accurate prognostic factor than the simple mitotic index. The results uphold the traditional classification histologic criteria and demonstrate the significance of VCMI as a reliable index of mitotic activity.

Analysis of Variance↗
PubMed1996

Morphologic differences between latent membrane protein-1 (LMP-1)-positive and negative tumour cells in Epstein-Barr virus (EBV)-related childhood Hodgkin's disease. A morphometric study.

The values of five cellular morphometric parameters (longest and shortest cytoplasmic axis, cellular circumference, area and roundness coefficient) were compared between 20 Latent Membrane Protein 1 (LMP-1)-positive and an equal number of LMP-1-negative Reed-Sternberg and Hodgkin (HRS) cells for each of 13 cases of Hodgkin's disease (HD) occurring in children (aged 3-15 years); the presence of Epstein-Barr virus (EBV) encoded EBER mRNAs had previously been detected in all cases using RNA in situ hybridisation (RISH), while the presence of LMP-1 was immunohistochemically detected using the alkaline phosphatase-antialkaline phosphatase (APAAP) method. The longest and shortest axis, circumference and area were larger in LMP-1-positive than in LMP-1 negative HRS cells, while the roundness coefficient of LMP-positive HRS cells was smaller than that of LMP-1 negative cells. All differences were statistically highly significant when univariate (paired comparisons) t-test were used. Multivariate analysis (Hotelling's T2 test) showed all differences (except the roundness coefficient) to be significant both at the 5% and 1% level of significance. These results provide a numerical basis for the alteration brought by the expression of LMP-1 in the cellular skeleton of tumour (HRS) cells in EBV-related childhood HD cases.

Adolescent↗
PubMed1995

Supporting telemicroscopy and laboratory medicine activities. The Greek "TELE.INFO.MED.LAB" project.

In this paper the authors present the basic results of the study for the "TELE.INFO.MED.LAB" project. This study is based on the local experience of the Metaxas Cancer Institute case and on international references. The possibilities rendered by current developments in telemedicine and particularly in telepathology accelerate and facilitate the communication of crucial medical data and creation of "second level" medical services overcoming the geographical particularities of the country. The availability of data transmission (signals, images, texts, etc.) enables the creation of a "uniform market" for various services. This system must take into account the financial realities, geographical aspects transportation problems and technological developments. Organization of this system, the choices of technical standards and the realization of a complete pilot project are described. For this system we also describe the functional and technical aspects, as well as software and hardware components for the different types of units.

Computer Communication Networks↗
PubMed1993

Vascular density and the response of breast carcinomas to mastectomy and adjuvant chemotherapy.

Using morphometric analysis of histological preparations, in a retrospective study vascular indices, expressing the extent of vascularisation, were determined for a number of mammary carcinomas. The indices were found to be related to the survival of the patients treated with modified radical mastectomy in combination with pre- and postoperative chemotherapy, the cases with low indices having the shorter survival. The impaired access of the cytotoxic agents to cells in the deficiently vascularised tumours was considered as an explanation. It was concluded that determination of vascular density in tumours may have a prognostic value in regard to the treatment response, and may be helpful in choosing the appropriate treatment.

Adult↗
PubMed1993

Nuclear morphometry as a prognostic factor in laryngeal squamous cell carcinomas. Preliminary study.

A preliminary report concerning the prognostic significance of certain nuclear morphometric parameters in laryngeal squamous cell carcinoma (SCC) is presented. 18 cases of primarily glottic laryngeal SCC were graded according to the criteria outlined by Jakobsson et al., and assessed for the presence of infiltration of laryngeal cartilage. Nuclear width (short axis) and perimeter were found to be smaller in the "favourable prognosis" group than in the "unfavourable prognosis" one, on an indicative basis only, due to the small number of cases. The nuclear perimeter was furthermore found to be larger in cases with carcinomatous infiltration of the laryngeal cartilage than in cases without, on a statistically highly significant basis. The clinical utility of these results in a biopsy report of a laryngeal SCC is discussed.

Adult↗
PubMed1992

Telepathology in Greece. Experience of the Metaxas Cancer Institute.

This paper deals with the description of a telecommunication project which is initiated by Metaxas Pathology Laboratory. In the first section we discuss a comprehensive computer supported information system which was installed in the laboratory. Special emphasis is given at the design of the communication subsystem. Then, the configuration of the diagnostic equipment is described. The last section of the paper focuses on the discussion of the experimental use of an integrated "low cost" system for interconnection among the Metaxas Pathology laboratory, the Pathology Department of the University of Crete, and the Technological Educational Institute (TEI) of Athens.

Cancer Care Facilities↗
PubMedDate not supplied

ras gene mutations in human endometrial carcinoma.

The purpose of this study was to assess the extent of involvement of the ras oncogene activation by point mutations in endometrial carcinoma in the Greek population. The PCR technique was employed, followed by RFLP analysis to identify the point mutations in codon 12 of the K-ras, H-ras and N-ras genes. K-ras gene point mutations were detected in 8 of the 55 cases (15%) of primary endometrial carcinoma, H-ras in 4 (7.3%), while no mutations were found for the N-ras gene. No correlation was found between the presence of ras gene mutations and the clinicopathological parameters, or patient survival. The only association found was between H-ras mutations and the FIGO stage of the tumor (Fisher's exact test, p = 0.011). These results indicate a possible role of ras gene activation in a small subset of endometrial carcinomas.

Carcinoma↗
PubMedDate not supplied

A new expert system for histopathological diagnosis of human ovarian epithelial cancer.

A new rule-based expert system designed to assist pathologists in the histological diagnosis of human ovarian epithelial cancer has been developed. The system was implemented using the INSIGHT II+ EXPERT System Shell and runs on IBM compatible microcomputers. It operates using knowledge acquired through the literature, research and experience, formulated into a total of 195 IF-THEN rules. The WHO International Histological Classification of Tumours is being used throughout. The system can quickly focus on a differential problem, thereby reducing the time necessary to reach a conclusion. It has been tested on a set of 34 cases, previously examined by pathologists of the Metaxas Memorial Cancer Institute, and has been found to reach good agreement with the pathologists' diagnoses.

Epithelium↗
PubMedDate not supplied

Information retrieval for pathology information systems.

In a medical information system there is a serious need for assessing patient information in various ways. There is also a need for summarizing information in simple statistical tabular form. In this part we present and evaluate different techniques for query formulation, such as: QBE (Query-by-Example), SQL (Structured Query Language), GCL (Graphical Query Language). We also present a query processor for use in a pathology information system. This software system incorporates: a) A semi graphical tree structure interface (SGTSI) for query formulation, and b) Summary tables handling.

Adult↗