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Biomedical subjects

B Molnár

Publications and source records attributed to B Molnár.

At least 19 recordsLinked to original sources
PubMed2001

[Determination of cagA, vacA genotypes of Helicobacter pylori with real-time PCR-method].

Presence of cagA gene of Helicobacter pylori (H. pylori) increases proliferation of stomach mucosa and it is an index of raised virulence of the bacteria. The vacA gene of H. pylori induces a serious inflammation of stomach. The purpose of this study was to determine cagA and vacA genotypes of H. pylori using real-time polymerase chain reaction (PCR) method with the double strain DNA-(dsDNA) binding SYBR Green I. dye. Results were compared with those of two immunohistochemical methods. 43 patients' paraffin embedded biopsy tissue samples were examined by histology, epidermal growth factor receptor (EGFR), proliferating cell nuclear antigen (PCNA) immunohistochemistry and melting curve analysis of real-time PCR using LightCycler instrument. Results of histology and real-time PCR from gastric biopsies correlated in 57% of cag acases and in 58% of vac cases. Significant difference was detected between normal and gastritis cases in the presence of cagA gene (p = 0.003) and between normal epithelial and intestinal metaplasia cases in the presence of vacA gene (p = 0.045) by investigation of association of histology and genotype of bacterium. Statistically significant difference (p = 0.02) was found between increased cell proliferation and the presence of gastritis. Significant correlation was found between the presence of cagA gene and EGFR expression in intestinal metaplasia cases (p = 0.0418). Results underlie the statistics that infection with cagA positive H. pylori strain increases the cell proliferation on the stomach mucosa and raises the chance of development of intestinal metaplasia. Infection with vacA positive H. pylori inhibits the signal-transduction pathway of EGFR, which influences mechanisms of mucosa repair. The role of EGFR and H. pylori infection is yet unclear in intestinal metaplasia and cancer. The authors' method seem to be suitable for determination of genotypes of H. pylori.

Antigens, Bacterial↗
PubMed2000

[Effect of Helicobacter pylori infection and eradication on proliferative kinetics of the gastric mucosa].

Helicobacter pylori infection is associated with an increased cell proliferation activity, however the exact mechanisms have not been elucidated. Our aim was to study the effect of Helicobacter pylori infection on normal gastric epithelia, gastritis, intestinal metaplasia and carcinoma by the expression of proliferating cell nuclear antigen and nucleolus organizer regions. Antral biopsies were taken from 121 patients (61 women, 60 men; mean age 58.5 y.). Sections were scored for normal epithelia (n = 15), gastritis without intestinal metaplasia (n = 74), gastritis with intestinal metaplasia (n = 24) and gastric carcinoma (n = 8). 52 patients had H. pylori positive gastritis, and success of eradication therapy was controlled in 34 cases. To characterize cell proliferation immunohistochemistry (PCNA) and histochemistry methods (AgNOR) were used. Results of PCNA and AgNOR significantly correlated except of that in the intestinal metaplasia group. PCNA LI and AgNOR counts were not significant higher in H. pylori positive compared to the H. pylori negative gastritis. Presence of H. pylori caused higher proliferation rate in intestinal metaplasia group measured by PCNA. In the group of intestinal metaplasia the proliferation activity decreased to the activity of the normal epithelia after the successful eradication, but remained high if eradication therapy was failed. Our results suggest, that H. pylori infection plays only as a co-factor in gastric carcinogenesis. Results were controversial in the intestinal metaplasia group, that can be explained by the heterogeneity of the bacteria.

Adult↗
PubMed2000

[Molecular biology characteristics of Helicobacter pylori].

Attention has been recently adverted to the Helicobacter pylori (H. pylori) by the fact, that its association with occurrence of gastroduodenal ulcer and gastric carcinoma had been justified. Our current understanding about metabolism and physiology of it is still not full, however, great strides have been made as for the methods of investigation during the last 16 years. Complete genome sequence of pathogenic strain of the bacteria have recently became identified, by which certain fundamental aspects of biology of H. pylori have been highlighted. Based on data, infection may presumably act as a cofactor to the development of peptic ulcer disease and carcinogenesis, however, details of pathomechanism are still unclear. Variability and genotype of bacteria, immune reactions and genetic patterns of host organism and mechanisms sustaining the balance of mucosal integrity may have additional influence. This study provides an overview on the current understanding about molecular biology of H. pylori.

Adenocarcinoma↗
PubMed2000

[Detection of aneuploidy from gastrointestinal biopsy samples].

Aim of the present work was the development of a mechanic cell separation protocol for gastrointestinal biopsy analysis. Evaluation of the technique was performed on selected group of patients who underwent routine endoscopy. Routine gastrointestinal biopsies were obtained after informed consent. 23 gastric (6 healthy, 14 gastritis, 3 adenocarcinoma) and 15 colon samples (5 healthy, 7 colitis ulcerosa, 3 adenocarcinoma) were evaluated. The mechanic disruption of the biopsies was performed by Medimachine (DAKO, Denmark), a commercially available system using a 30 microns miner and a 30 microns mesh. The cell solution was centrifuged for 5 minutes by 250 g. The cells were fixed in paraformaldehide and stained by propidium iodide. The flow cytometry analysis was performed on a BD FacStar Plus flow cytometer. The DNA data were evaluated using the Winlist software. All of the preparations were appropriate for flow cytometric analysis. The coefficient of variation of the DNA histograms (n = 7) (CV mean +/- SD. 6.45% +/- 1.21) were acceptable for analysis. In the gastric biopsy samples aneuploidy was determined only in malignant cases. In four of the seven colitis ulcerosa samples and in one of the three adenocarcinoma aneploidy was found. The histologically healthy specimen were all diploid. Mechanic cell separation and disaggregation is a useful method for preparing fresh biopsy specimen for flow cytometry.

Adenocarcinoma↗
PubMed2000

Can intravascular lymphomatosis mimic sinus thrombosis? A case report with 8 months' follow-up and fatal outcome.

We report a case of intravascular lymphomatosis of the brain with 8 months' follow-up and fatal outcome. Several MRI investigations revealed variegated, rapidly changing infarct-like lesions and invasion of the walls of the superior sagittal sinus and deep veins. When disturbances of the venous outflow are detected with multifocal infarct-like lesions, intravascular lymphomatosis should be considered in the differential diagnosis. Brain biopsy may ensure the proper diagnosis ante mortem, but failure of biopsy is frequent, as in our case.

Adult↗
PubMed2000

Quantitative DNA and morphometric analysis of gastroscopic brush smears by TV image analysis.

OBJECTIVES: To determine quantitative nuclear morpho-and densitometric classifiers and classification techniques for analysis of gastric, Feulgen-stained brush smears. DESIGN: TV image analysis-based quantitative DNA and morphometric analysis of gastric brush smears in a prospective study. PATIENTS AND METHODS: Ninety-eight (11 normal, 77 gastritis (17 with intestinal metaplasia) and 10 adenocarcinoma) Feulgen-Schiff-stained gastric brush smears were analysed by TV image analysis. The classification of the smears was based on parallel histological examination. For standards, DNA content of lymphocyte cell cultures was determined by the image and by flow cytometry. From every nucleus, six morphometric (surface, layers, minimum diameter, maximum diameter, perimeter and form factor) and six densitometric (integrated optical density (IOD), average density, sigma density, minimum and maximum density and density range) parameters were simultaneously determined. The smear parameters (object cells CV, DNA index, 2c deviation index, 5c exceeding rate, G1 -S-G2 ratio) were analysed together with the mean and SD values of the nuclear parameters by discriminant analysis and back-propagation neural networks. RESULT: The normal smears were all diploid and their S + G2 ratio was 15.24+/-7.75% (mean +/- SD). The gastritis smears were all diploid with a proliferation fraction of 20.89+/-6.75%. The tumours were aneuploid in eight of the ten cases with 5c exceeding rate > 6.23%, the S + G2 fraction ratio was 34.72+/-10.12%. The mean nuclear surface area was 46+/-20, 58+/-20 and 74+/-22 microm2 in normal, gastritis and malignant groups, respectively. Significant differences (P<0.05) were found in nuclear surface, minimum and maximum diameter, and perimeter parameters. Using linear discriminant analysis, 100% of the non-malignant cases and 70% of the tumour cases were correctly classified. Using 30 non-malignant and five malignant cases as a training set, the neural networks classified 95% of the remaining cases correctly. The DNA index increased significantly (P<0.05) in Helicobacter pylori-positive cases compared to the negative ones. In gastritis with intestinal metaplasia, the proliferation ratio decreased significantly (P<0.05). CONCLUSIONS: The image analysis is a useful tool for quantitative gastric cytology. The combination of nuclear morphometric parameters and neural network classifiers with multivariate quantitative DNA analysis is suggested for gastric brush smear quantitative cytology analysis.

Adenocarcinoma↗
PubMed2000

Increased cell proliferation in chronic Helicobacter pylori positive gastritis and gastric carcinoma--correlation between immuno-histochemistry and Tv image cytometry.

BACKGROUND: [corrected] Epithelial cell proliferation activity has been reported both to be unaltered and increased in Helicobacter pylori (H. pylori) associated chronic gastritis. The proliferation rate decreased following H. pylori eradication, but results are controversial whether this change is dependent on the success of eradication. We compared the cell proliferation activity of H. pylori positive and negative gastric epithelial biopsies in chronic gastritis with and without intestinal metaplasia (IM) and gastric cancer by the expression of proliferation cell nuclear antigen (PCNA) and Tv image cytometry, and assessed the effect of H. pylori eradication on the cell proliferation rate in the gastric epithelium. METHODS: Brush smears and antral biopsies were taken from 70 patients (42 men, 28 women, mean age 58+/-15 y.o.) on routine endoscopy. Patients were divided into four groups according to the histology; normal epithelia (n = 10), chronic gastritis without IM (n = 24), chronic gastritis with IM (n = 20), and gastric carcinoma (n = 16). Thirty-three patients were H. pylori positive, and success of eradication was controlled in 24 cases. Cell proliferation was measured by immunohistochemistry using PCNA labeling index (LI) and by Tv image cytometry evaluating 12 morpho- and densitometric parameters of each nuclei and 6 additional parameters of each smear. RESULTS: PCNA LI, DNA index and S + G2 ratio were all higher in chronic gastritis than in the normal epithelium, and were further increased in carcinoma. The lower PCNA LI observed in chronic gastritis with IM corresponds to the lower S phase ratio determined by Tv image analysis. In H. pylori positive cases, the proliferation activity was 69.3+/-13.05% prior to the eradication and it decreased to 55.8+/-23.31% after the successful eradication therapy. When immunohistochemistry was compared with Tv image cytometry, PCNA LI significantly correlated with the percentage of cells in GL phase (r = -0.415) and S phase (r = 0.385), Integrated Optical Density mean (r = 0.598), density maximum (r'= 0.608), surface (r = 0.670), layers (r = 0.638), diameter minimum (r = 0.619), diameter maximum (r = 0.730) and perimeter (r = 0.501), respectively (p < 0.05). CONCLUSIONS: Epithelial cell turnover is increased in chronic gastritis with or without IM, and in gastric carcinoma. The lower PCNA LI observed in chronic gastritis with IM corresponds to the lower S phase ratio determined by Tv image analysis. Cell proliferation decreases after successful H. pylori eradication. Both methods proved to be reliable for the determination of epithelial cell proliferation.

Adult↗
PubMed1999

[Effect of Helicobacter pylori infection on the apoptotic and cell proliferative processes of the gastric mucosa].

The role of the Helicobacter pylori in the induction of gastric carcinogenesis seems to be certain. The exact pathomechanism is not yet known, although the special genetic conditions both of the microbe and the host just as the imbalance of the apoptotic and proliferative processes caused by the chronic inflammation are assumed to be involved. The latter one can be proved by the use of different cell proliferative and apoptotic markers. The results are inconsistent whether the eradication therapy causes the regression of premalignant atrophic gastritis. The regression of the MALT-associated lymphoma after the eradication therapy seems to be more convincing. The need of the eradication to prevent gastric cancer can be judged by the follow-up of some biomarkers (e.g. HLA II genotype, PCNA index, anti HP-IgA titer and the serum pepsinogen level), although their diagnostical application could be hardly introduced in the everyday practise so far.

Apoptosis↗
PubMed1998

[Biologic detection methods in the comparison of circulating tumor cells and micrometastases].

Early studies could not prove any diagnostic or prognostic value of the presence of tumor cells in the circulation. Recent knowledge in the field of molecular and cellular pathology provided better understanding of mechanisms of metastasis formation therefore advanced detection of circulating cancer cells has been suggested as a supplementary method of staging metastatic cancer. Beside the widely used immunocytochemical methods the reverse transcriptase-polymerase chain reaction (RT-PCR) is now the most relevant technique in studying micrometastases of solid tumors. Magnetic activated cell sorting (MACS) is a recently developed method for the enrichment of different cells from suspensions by magnetic labelling of their surface antigens. RT-PCR seems to be the most sensitive to detect circulating cancer cells or micrometastases, but it is possible by MACS to purify cells for further immunological, biochemical or genetic analysis. The aim of this review is to give a brief summary of recently used methods and to discuss the clinical relevance of the attainable results.

Biomarkers, Tumor↗
PubMed1998

[Incidence and elimination of false-negative results of ferritin determination].

Introduction of turbidimetric homogeneous immunoassays made the determination of plasma ferritin concentration wide-ranging available. However, high-dose hook effect or prozone effect occurring at samples with high ferritin concentration can lead to false-negative results. According to the authors, this phenomenon has considerable clinical significance, in patients with iron-overload disorders false-negative laboratory values may result in inaccurate diagnosis. The prozone effect can be eliminated by reaction kinetic analysis of measurements. The authors developed a neural network classification procedure based on artificial intelligence technology for the recognition of the reactions with differing kinetic flow, and made a computer software for helping the application of the classification system. False-negative results can be filtered using this new technology following the laboratory determination, thus sensitivity of plasma ferritin determination may become safe enough even in case of high concentration samples.

False Negative Reactions↗
PubMed1998

[Computerized speech recognition-based endoscopic findings].

Discrete, Hidden Markov model based speech recognition and phoneme based speech synthesis techniques were applied for gastroscopy reporting and machine control. The authors developed a special program for grammatical analysis of the sentences. Altogether 100 patient findings were grammatically analysed. The sentences were grouped according to the topographical order of the investigation: oesophagus, cardia, fundus, corpus, antrum, pylorus, bulbus, postbulbar section, and the pathological findings: erosion, ulceration, malignancy. Speech samples from 3 deep voiced male investigators were collected. The recognition rate was above 95%. A simulation program was also developed for dictation and controlling of the different equipment (monitor, printer, video, endoscope) in the gastroscopy laboratory by speech recognition. Speech synthesis was applied for the evaluation of understanding. This module artificially synthesizes the answer of the system giving backup for the understood information. With additional developments the discrete word speech 'recognition' achieved the level of routine application in medical reporting. However, ready-to-use developments need the joint activity of speech technology and endoscopy industry with end-user teams.

Diagnosis, Computer-Assisted↗
PubMed1998

[Medical use of artificial neural networks].

The main aim of the research in medical diagnostics is to develop more exact, cost-effective and handsome systems, procedures and methods for supporting the clinicians. In their paper the authors introduce a new method that recently came into the focus referred to as artificial neural networks. Based on the literature of the past 5-6 years they give a brief review--highlighting the most important ones--showing the idea behind neural networks, what they are used for in the medical field. The definition, structure and operation of neural networks are discussed. In the application part they collect examples in order to give an insight in the neural network application research. It is emphasised that in the near future basically new diagnostic equipment can be developed based on this new technology in the field of ECG, EEG and macroscopic and microscopic image analysis systems.

Artificial Intelligence↗
PubMed1997

Laser surgery of the vocal cord.

A total of 1032 vocal cord operations have been performed by means of CO2 laser in the Department of Otorhinolaryngology, Head and Neck Surgery of the Semmelweis University of Medicine in Budapest in the past 10 years. There were 687 benign cases and 345 malignant cases of lesions discovered. The procedures were performed under general anesthesia in many instances with jet narcosis--in laryngomicroscopic exposure. The operations were preceded by careful objective diagnostics, such as videolaryngostroboscopy, fiberoscopy, voice analysis, airflow and resistance measurements, while the voice and breathing functions were monitored postoperatively. Our policy in the therapy of the benign lesions was always to use a minimally invasive technique, avoiding damage to the anterior commissure, the vocal ligament and the subglottic space. We have experienced a 3-year survival rate in 87% of the patients with vocal cord carcinomas. According to the results of the past 10 years it is proven that the CO2 laser technique is an efficient method as well in the surgery of the benign and malignant vocal cord lesions, as in the bilateral vocal cord paralysis. Laser surgery might also prevent malignant transformation in precancerous vocal cord diseases.

Humans↗
PubMed1992

[The use of multivariate mathematical methods in medical diagnostic systems--a model for the evaluation of cytological smears].

The methods of the multivariate mathematics have been applied in several studies to increase the diagnostic reliability of medical decision support system. In the recent years some new algorithms for decision support (fuzzy logic) and for pattern recognition (neural nets), both specified by nonlinearity, were developed. This paper provides results for the application of this methods in the area of quantitative cytology and the comparison with the traditional classifiers. 21 normal, 15 dysplastic, 23 malignant, Feulgen stained gastric imprint smears were analysed on a Leitz Miamed DNA equipment. The determination of mean DNA content, the 2c deviation index (2cDI), 5c Exceeding rate (RcER), G1,S,G2 phase fraction ratios, cell nucleus area, form factor was performed. The discriminant analysis classified correctly the 95.6% of malignant cases, 86.7% of dysplasias, and 80.7% normal cases. Our diagnostic system using fuzzy logic made the diagnostic borders fine tuneable, and reliable. The back propagation neural net could classify all three diagnostic groups above 95% correctly. The application of nonlinear computational methods made the diagnostic system more reliable. The application of these algorithms are encouraged.

Algorithms↗
PubMed1992

[Quantitative morpho- and densitometric parameters in the evaluation of aspiration cytology smears of the breast].

Quantitative morpho- and densitometric analysis of Feulgen stained breast aspiration smears were performed by absorption cytophotometer and a TV image analyser. The DNA Index, and the ratio of G1-S-G2 phase fraction ratio yielded by the quantitative DNA analysis, showed significant differences between benign and malignant alterations. Based on the 13 morphometric and 5 densitometric parameters the TV-image analyser could classify the examined smears 80% correctly by cluster analysis. Groups of the cytological Grade I.-III. were also differentiable by this method. The application of TV image analyser system in the diagnosis of aspiration cytological smears could be suggested. The complex quantitative morpho- and densitometric analysis could contribute to the correct classification of diploid tumours.

Biopsy, Needle↗
PubMed1992

Determination of G1-S-G2 phase fraction ratios of tumour subpopulations from DNA histograms.

Authors describe a new mathematical approach based on mixture decomposition and maximum likelihood method for the determination of subpopulations and G1-S-G2 phase fraction ratios in aneuploid, multiploid DNA histograms. A special computer routine was developed for this purpose (DAHSY). The present study relates to DNA histograms obtained by a Leitz Miamed DNA TV image analyser system. Altogether 23 normal, 14 dysplastic and 28 tumours Feulgen stained gastric imprint smears were measured. In addition to determination of subpopulations and G1-S-G2 phase fraction ratios, the authors also performed a morphometric analysis of Feulgen stained nuclei and determined the values of 5c exceeding rate (5cER) and the 2c deviation index (2cDI). More than one subpopulation were found only in tumours. The usual G1-S-G2 phase fraction rates in normal gastric smears were 85.5%, 9.04%, 4.9%, in dysplastic cases 74%, 15.4%, 10.2% and in tumours 53.8%, 22.9%, 18.8%. Significance of the differences were calculated by the T-test. The G1 phase fraction ratio clearly discriminates the malignant lesions from all others. The S+G2 phase fraction ratio, however, distinguishes the normal cases from the dysplastic ones. The 2cDi and 5cEr could support a multivariate diagnostic system. The cell nucleus area was found also to be of diagnostic value.

Algorithms↗
PubMed1992

DNASK--a new image analysis module for TV image cytometry.

The DNASK is a PC-based image analysis module for quantitative cytological and histological examinations on Feulgen-Schiff preparations. The module consists of a frame grabber, a CCD black and white video camera and the DNASK software package which can be incorporated in an IBM compatible PC-AT joining to a standard pathological research photo microscope. The use of 386 IBM AT systems leads to significant decrease of the measurement's time. Mono- or color VGA graphics card should be used. The resolution of the images is 512 x 512 pixels and 256 gray values. The image caption is made in less than 0.5 second, the measurement of a cell nuclei (18 parameters) takes less, than 5 seconds (IBM AT 286). The camera is a standard CCD one. The microscope should be a good quality, modern microscope with built-in light source, however, the application of voltage stabiliser is strongly recommended. The software is able to measure the parameters mostly used and suggested in the international literature: 15 morpho- and densitometric parameters of the cell nuclei 6 DNA histogram parameters of the measured case, like DNA Index, 2c deviation Index, 5c exceeding rate, G1-S-G2 phase fraction ratio. The system supports the grouping of the measured cases and at the end of a study results of the single measurements can be collected and summarized in an ASCII file, which is readable by major statistical programpackages. The DNASK has a special graphical user interface for the control of the program.

Algorithms↗