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Biomedical subjects

P Nagy

Publications and source records attributed to P Nagy.

At least 19 recordsLinked to original sources
PubMed2006

Adhesion formation with open versus laparoscopic cholecystectomy: an immunologic and histologic study.

BACKGROUND: This randomized study aimed to compare the reaction of the immune system to the process of postoperative adhesion formation after open and laparoscopic cholecystectomy. METHODS: In this study, 20 mongrel dogs were used: 10 each in the laparoscopic and open cholecystectomy groups. Blood and peritoneal lavage samples were taken up to postoperative day 14, followed by second-look laparoscopy and reoperation to detect the rate of adhesion formation. Also, specimens were obtained from the liver bed for histology. RESULTS: In the open cholecystectomy group, the white blood cell count was higher in blood samples and lower in lavage specimens. Adhesion formation was extensive, and the histologic immune reaction was more intensive in the open cholecystectomy group. CONCLUSION: This randomized study proved that laparoscopic cholecystectomy was associated with less immune suppression, less inflammatory reaction, and therefore less adhesion formation than open cholecystectomy.

Animals↗
PubMed2005

Mutation scanning of the p53 tumor suppressor gene in renal and liver transplant patients in Hungary.

INTRODUCTION: The increased incidence of malignancies among transplanted patients is well known. Abnormal function of the p53 tumor suppressor gene has been reported in more than half of all tumors. The aim of our study was to detect point mutations of p53 gene in transplanted patients because the presence of mutations may be a predictive factor for tumor development. An earlier diagnosis can help to develop new strategies for immunosuppressive therapies. METHODS: Three point mutations were chosen based on the literature: exon5-codon175, exon7-codon248, exon8-codon273. Genomic DNA from the plasma of 60 liver, 362 renal transplants, and 45 nontransplanted patients with different tumors and 20 suspected healthy patients were analyzed with a real-time PCR method using the Roche LightCycler. The mutations were evaluated by melting curve analysis. RESULTS: We elaborated a special protocol for scanning the above mentioned p53 point mutations, which were proved by sequencing as well. Among 487 patients, 486 showed a wild-type genotype. The only patient carrying a mutation at codon 273 (heterozygous) was a liver transplant patient, who developed pancreas carcinoma and had already died. CONCLUSION: Our data suggest that mutations of the targeted codons in leukocyte DNA seem to be rare, but a mutation could be lethal. The evaluated three point mutations of p53 gene were not predictive for tumor development.

Base Sequence↗
PubMed2004

Factors affecting plasma progesterone concentration and the retrospective determination of time of ovulation in cyclic mares.

Factors influencing plasma progesterone concentration were investigated in seven mares. Two-phase logistic curves were fitted (r=0.98) to plasma progesterone concentrations of blood samples collected once daily. In addition to the effect of time (P<0.001), there were differences (P<0.01) among mares in the peak height of the progesterone plateau and in the (area under the curve) AUC. Plasma progesterone concentrations were higher (P<0.001) after a multiple versus single ovulation. There was an effect of season (P<0.001), but no significant effect of luteal morphology. The retrospective determination of time of ovulation was carried out using a linear model on the seven mares and 25 additional mares. Linear regression on the measured values or on the ratio to the average concentration from D5 to D10, was calculated with the day of cycle between D0 and D4. The ovulation date was then calculated using both of these equations, whether blood sampling was performed twice or thrice weekly on 25 postpartum mares. The accuracy to predict day of ovulation (+/- 1 day) ranged from 88 to 97%. In conclusion, the retrospective estimation of time of ovulation in mares was possible, although the technique had some limitations.

Animals↗
PubMed2004

Effect of static magnetic field on growth and sporulation of some plant pathogenic fungi.

Growth and sporulation of phytopathogenic microscopic fungi were studied under a static magnetic field. The applied flux densities were 0.1, 0.5, and 1 mT. The magnetic field decreased the growth of colonies by 10% using this flux density region. At 0.1 mT flux density, the deviations are significant, P =.001, while in other cases the deviations generally are not significant. At the same time, the number of the developed conidia of Alternaria alternata and Curvularia inaequalis increased by 68-133%, but the number of Fusarium oxysporum conidia decreased by 79-83%. The deviations are generally significant at the P =.05 level.

Fungi↗
PubMed2003

Dynamic, yet structured: The cell membrane three decades after the Singer-Nicolson model.

The fluid mosaic membrane model proved to be a very useful hypothesis in explaining many, but certainly not all, phenomena taking place in biological membranes. New experimental data show that the compartmentalization of membrane components can be as important for effective signal transduction as is the fluidity of the membrane. In this work, we pay tribute to the Singer-Nicolson model, which is near its 30th anniversary, honoring its basic features, "mosaicism" and "diffusion," which predict the interspersion of proteins and lipids and their ability to undergo dynamic rearrangement via Brownian motion. At the same time, modifications based on quantitative data are proposed, highlighting the often genetically predestined, yet flexible, multilevel structure implementing a vast complexity of cellular functions. This new "dynamically structured mosaic model" bears the following characteristics: emphasis is shifted from fluidity to mosaicism, which, in our interpretation, means nonrandom codistribution patterns of specific kinds of membrane proteins forming small-scale clusters at the molecular level and large-scale clusters (groups of clusters, islands) at the submicrometer level. The cohesive forces, which maintain these assemblies as principal elements of the membranes, originate from within a microdomain structure, where lipid-lipid, protein-protein, and protein-lipid interactions, as well as sub- and supramembrane (cytoskeletal, extracellular matrix, other cell) effectors, many of them genetically predestined, play equally important roles. The concept of fluidity in the original model now is interpreted as permissiveness of the architecture to continuous, dynamic restructuring of the molecular- and higher-level clusters according to the needs of the cell and as evoked by the environment.

Animals↗
PubMed2003

STAT-3 activity in chemically-induced hepatocellular carcinoma.

The signal transducer and activator of transcription (STAT)-3 regulates basic biological processes and it has been reported to be constitutively active in different types of malignant tumours. STAT-3 is active during the regenerative growth of the liver, but there are hardly any data about its presence in liver tumours. We investigated and found a high activity of STAT-3 using an electrophoretic mobility shift assay (EMSA) in chemically-induced rat hepatocellular carcinomas (HCCs). Dexamethasone treatment downregulated both STAT-3 activity and cell proliferation in the tumours. Therefore, the activity of the STAT-3 signal transduction pathway seems to be required for the growth of HCCs and could be a potential new target for therapeutic trials of this tumour type.

2-Acetylaminofluorene↗
PubMed2003

Imaging molecular interactions in cells by dynamic and static fluorescence anisotropy (rFLIM and emFRET).

We report the implementation and exploitation of fluorescence polarization measurements, in the form of anisotropy fluorescence lifetime imaging microscopy (rFLIM) and energy migration Förster resonance energy transfer (emFRET) modalities, for wide-field, confocal laser-scanning microscopy and flow cytometry of cells. These methods permit the assessment of rotational motion, association and proximity of cellular proteins in vivo. They are particularly applicable to probes generated by fusions of visible fluorescence proteins, as exemplified by studies of the erbB receptor tyrosine kinases involved in growth-factor-mediated signal transduction.

Animals↗
PubMed2003

Induced lactation with a dopamine antagonist in mares: different responses between ovariectomized and intact mares.

The aim of this study was to compare the effects of treatment with repeated injections of sulpiride (a dopamine D2 antagonist) on prolactin secretion and induced lactation in ovariectomized and intact adult mares and to verify if this induction was possible at the beginning and at the end of the birth season. Two experiments were carried out in September [experiment (expt) 1], and in March (expt 2), in France (48 degrees N). In expt 1, three groups of five mares were tested: intact-control, intact-treated and ovariectomized-treated mares. In expt 2, mares previously subjected to artificial photoperiod were assigned in two groups: four intact-control and five intact-treated mares. The cyclicity of intact mares was previously synchronized with PGF2alpha injections, then all the mares were in the follicular phase at the beginning of treatment. Sulpiride was intramuscularly injected (0.5 mg/kg of BW), twice a day. Mares were milked at 7:30, 11:45, 16:00 and 20:15 hours. Blood samples were collected every day during the treatment for progesterone, total oestrogen and prolactin assays. In the two experiments, only treated intact mares produced milk, with a large inter-animal variability. Prolactin increase after sulpiride treatment was not so great in the ovariectomized-treated mares as in the intact-treated mares. The total correlations between prolactin, progesterone, oestrogen plasma concentrations and daily milk production were significant (0.57, 0.25, 0.17 respectively). This induction of lactation can be performed during the entire birth season in intact mares, but not in ovariectomized mares, indicating that steroids are necessary for this induction in mares treated by dopamine D2 antagonist.

Animals↗
PubMed2002

Esophageal intramural metastasis from adenocarcinoma of the gastroesophageal junction.

Among a total of 143 patients examined for diagnosis of adenocarcinoma of the cardia, intramural esophageal metastases were verified in six patients (4.19 %). In each case the diagnosis was confirmed by histological examination. The histological structure of the primary tumors and metastases was the same. Metastases were detected by endoscopic ultrasound examination in three cases. All the cardia tumors proved to be well advanced. As well as endoscopic identification of the primary tumor, thorough examination of the proximal part of the esophagus is of great importance.

Adenocarcinoma↗
PubMed2001

[Adnexal torsion in childhood].

The authors report the case of a 10-year-old girl who was admitted with hypogastric complaints. Based on the examinations followed that, laparotomy was carried out, during which the torsion of the right-side adnexum was observed. During the case report special attention is put on the differential-diagnostic difficulties of adnexal torsion. The importance of the case is that we should think of this relatively rare disease even in childhood, because the early diagnosis and adequate therapy make possible to avoid the surgical amputation.

Adnexal Diseases↗
PubMed2001

Lipopolysaccharide and ceramide docking to CD14 provokes ligand-specific receptor clustering in rafts.

The glycosylphosphatidylinositol-anchored receptor CD14 plays a major role in the inflammatory response of monocytes to lipopolysaccharide. Here, we describe that ceramide, a constituent of atherogenic lipoproteins, binds to CD14 and induces clustering of CD14 to co-receptors in rafts. In resting cells, CD14 was associated with CD55, the Fcgamma-receptors CD32 and CD64 and the pentaspan CD47. Ceramide further recruited the complement receptor 3 (CD11b/CD18) and CD36 into proximity of CD14. Lipopolysaccharide, in addition, induced co-clustering with Toll-like receptor 4, Fcgamma-RIIIa (CD16a) and the tetraspanin CD81 while CD47 was dissociated. The different receptor complexes may be linked to ligand-specific cellular responses initiated by CD14.

Antigens, CD↗
PubMed2001

Origin and structural evolution of the early proliferating oval cells in rat liver.

We have analyzed the histological changes in rat liver after 2-acetylaminofluorene (AAF) administration. The data demonstrate that AAF-induced oval cells were preferentially generated by proliferation of the terminal biliary ductules that we suggest constitute the primary hepatic stem cell niche. The oval cells formed ductular structures, representing an extension of the canals of Hering. This histological organization provides continuous bile drainage of the hepatocytes and uninterrupted blood flow in the sinusoids. The oval cell ductules are surrounded by a continuous basement membrane that is intermittently disrupted by processes of stellate cells that form direct cell-cell contact with the oval cells. Although both AAF treatment and bile duct ligation results in proliferation of biliary epithelial cells, the mechanism(s) responsible for the proliferation of the biliary epithelium seems to differ in the two models. In contrast to the biliary proliferation stimulated by bile ligation, AAF-induced oval cell proliferation as well as the capacity of these cells to differentiate into hepatocytes, bile epithelial cells and possibly other cell lineages can be blocked by administration of dexamethasone.

2-Acetylaminofluorene↗
PubMed2001

A model for the hillock formation on graphite surfaces by 246 MeV Kr+ ions.

Scanning tunnelling microscopy has been used to study the effect of ion bombardment at different angles of incidence on a graphite surface. The 246 MeV energy of Kr+ ions was selected in the medium energy range, where the electronic and nuclear stopping is nearly balanced. The low dose (1 x 10(12)/cm2) of ions allows the characterization of single features caused by bombardment in perpendicular, at 30 degrees and at 60 degrees incidence. The density of hillocks caused by the ion bombardment is significantly lower than the ion dose and this density depends on the angle of incidence. The hillocks are attributed to knocked-on atoms leaving the sample surface. A simple model for the scattering process is presented to enlighten the hillock density differences. Other features produced by the ion bombardment, such as elongated traces and (square root of 3 x square root of 3) R30 superstructures are also reported.

Journal Article↗
PubMed2001

Immunohistochemical analysis of atypical ductular reaction in the human liver, with special emphasis on the presence of growth factors and their receptors.

AIMS/BACKGROUND: The objective of this study was to characterize the expression of transforming growth factor-alpha/epidermal growth factor receptor, hepatocyte growth factor/c-met, transforming growth factor-beta/Type I-II transforming growth factor-beta receptors, stem cell factor, urokinase plasminogen activator, smooth muscle actin, CD34 and alpha-fetoprotein in human liver samples with (sub)massive necrosis of different etiology containing atypical ductular reaction. METHODS: Their presence was studied by immunohistochemistry on paraffin-embedded tissue sections. RESULTS: Transforming growth factor-alpha and -beta, hepatocyte growth factor and their receptors were demonstrated in the ductules; additionally stem cell factor and urokinase plasminogen activator were also expressed. The atypical ductules were surrounded by smooth muscle actin-positive activated stellate cells. CONCLUSION: These phenotypic similarities confirm that the atypical ductules in the human liver may be equivalent of oval cells in the rat liver, which are regarded as the progeny of stem cells. That is, the atypical ductular proliferation may correspond to a stem cell-fed regenerative process.

Adolescent↗
PubMed2001

Reconstitution of liver mass via cellular hypertrophy in the rat.

The liver has an extremely effective regenerative capacity. When 70% of a rat liver is removed by surgery, the liver mass regrows in 7 to 10 days by the compensatory hyperplasia of the remnant part. In case of damage to the surviving hepatocytes, the facultative stem-cell compartment is activated and the liver regenerates by means of oval-cell proliferation/differentiation. In the present study, we demonstrate that when both hepatocyte proliferation and stem-cell activation were prevented by dexamethasone (Dex) administration, the liver mass was restored in the absence of DNA synthesis. The restoration of the liver was accomplished by the preferential enlargement/hypertrophy of the periportal hepatocytes. A similar response was observed when cell proliferation was arrested by 5-fluorouracil (FU) following partial hepatectomy. Therefore, the hepatocytic hypertrophy appears to provide an alternative mechanism of liver-mass restoration. This hypertrophic condition of the liver is not stable, because following the withdrawal of Dex, the enlarged hepatocytes entered in the cell cycle and the normal liver structure and DNA content was re-established.

Animals↗
PubMed2001

[What kind of surgical radicality is justified in the treatment of esophageal and cardial carcinoma?].

In the period from January 1, 1973 to November 30, 1994, a total number of 1 856 patients had been admitted to our Department of Surgery because of cancer of the esophagus and esophago-gastric junction. We divided our activities into two study periods. In the first study period from 1973 to 1984 only so called "conventional operations" were performed. Since 1985 new oncological aspects were introduced into our operative tactics:1. the subtotal esophagectomy combined with the two-field lymphadenectomy,2. the total gastrectomy with extended lymph node dissection. The analysis of our results with respect to the survival parameters (TNM staging, histological type, grade of differentiation, gross pathology) showed that the best chances were obtained by curative resection and lymphadenectomy in tumours of low-grade biologic malignancy. In esophageal cancers the former 6 % 5-year cumulative survival rate increased to 26 %, and in cardia tumours from 9 to 27 %, because of enhancement of radicality and extension of lymphadenectomy.

Adenocarcinoma↗