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Biomedical subjects

P Török

Publications and source records attributed to P Török.

At least 19 recordsLinked to original sources
PubMed2004

Predictive value of hysteroscopic examination in intrauterine abnormalities.

STUDY OBJECTIVE: This study was set up to evaluate the predictive value of hysteroscopic examination in patients referred to the Department of Obstetrics and Gynecology at the Medical and Health Science Center, Debrecen, Hungary. STUDY DESIGN: The authors performed 835 biopsies by hysteroscopy over more than 13 years. They compared their findings with histological findings held in a a computerized clinical database. RESULTS: The sensitivity of hysteroscopy was 0.52 for hyperplasia, 0.87 for polyps, 0.85 for myomas, 0.68 for carcinoma, and 0.73 for atrophy. CONCLUSION: It seems that for findings facing into the uterine cavity (such as submucosal myomas and peduncular polyps), hysteroscopy can predict the histological results. The evaluation of endometrial cycles and of the thickness of the endometrium by hysteroscopy is less accurate.

Atrophy↗
PubMed2003

Response to combination therapy with interferon alfa-2a and ribavirin in chronic hepatitis C according to a TNF-alpha promoter polymorphism.

BACKGROUND: Tumor necrosis factor-alpha (TNF-alpha) is involved in the pathogenesis of chronic active hepatitis C. Polymorphisms in the promoter region of the TNF-alpha gene can alter the TNF-alpha expression and modify the host immune response. The present study aimed at the correlation of the G308A TNF-alpha polymorphism with the response to antiviral combination therapy in chronic hepatitis C. PATIENTS AND METHODS: 62 patients with HCV and 119 healthy unrelated controls were genotyped for the G308A TNF-alpha promoter polymorphism. The patients received 3 x 3 million units of interferon alfa-2a and 1,000-1,200 mg ribavirin daily according to their body weight. A response was defined as absence of HCV-RNA and normalization of S-ALT after 6 months of combination therapy. RESULTS: With respect to the allele and genotype frequency, a significant difference was not observed between controls and patients with chronic hepatitis C. Furthermore, such a difference was also not observed if responders and non-responders to antiviral therapy were compared. CONCLUSIONS: The promoter polymorphism of the TNF-alpha gene investigated herein is equally distributed in healthy individuals and patients with hepatitis C and does not seem to predict the response to therapy with interferon alfa-2a and ribavirin.

Adult↗
PubMed2000

Focusing of electromagnetic waves by paraboloid mirrors. I. Theory.

We derive a solution to the problem of a plane electromagnetic wave focused by a parabolic mirror. The solution is obtained from the Stratton-Chu integral by solving a boundary-value problem. Our solution can be considered self-consistent. We also derive the far-field, i.e., Debye, approximation of our formulas. The solution shows that when the paraboloid is infinite, its focusing properties exhibit a dispersive behavior; that is, the structure of the field distribution in the vicinity of the focus strongly depends on the wavelength of the illumination. We show that for an infinite paraboloid the confinement of the focused energy worsens, with the energy distribution spreading in the focal plane. 2000 Optical Society of America [S0740-3232(00)01309-0] OCIS codes: 260.0260, 260.2110, 050.1960, 260.5430.

Journal Article↗
PubMed2000

Focusing of electromagnetic waves by paraboloid mirrors. II. Numerical results.

We present results of numerical computations obtained from a theory described in Part 1 of our current investigations [J. Opt. Soc. Am. A 17, 2081 (2000)]. We show that a segment of a paraboloid mirror produces an intensity distribution identical to that of a high-aperture lens. It is shown that when the convergence angle of the paraboloid is increased beyond the pi/2 limit, the lateral resolution in the direction orthogonal to the incident polarization improves, whereas in the other direction the resolution worsens. Numerical results show that paraboloid mirrors of high convergence angle exhibit dispersion; that is, when the focal length is altered by a quarter of the wavelength the intensity in the focus changes from its maximum to its minimum value. A focal shift is observed that, in the case of a paraboloid of low convergence angle is identical to the Fresnel shift. However, a focal shift is also observed at large convergence angles.

Journal Article↗
PubMed1997

[Multiple metastases of malignant cutaneous melanoma into the upper urinary tract].

The authors describe their case of the extremely rare multiple metastases of cutan melanoma malignum in the upper urinary tracts as it was treated with operations. In the case of their 17-year old patient first percutan resection of the right side of the renal pelvis-wall was done then one and half months later ureteronephrectomia was carried out on the right side because of metastases in the renal pelvis and the ureter. The primary tumour had been removed from the hairy area of the head 9 months earlier in a dermatological department. The authors have met only 14 similar cases in the international literature. In Hungary no review of any similar case has been found.

Adolescent↗
PubMed1996

Simple modification of a commercial scanning laser microscope to incorporate dark-field imaging.

Dark-field imaging modes have attracted less interest in biological confocal microscopy than the extensive applications of immunofluorescence imaging. There are, however, certain biological and materials science applications where it is necessary to use a confocal imaging mode that is capable of partial or full rejection of light specularly reflected from coverslips, microscope slides or specimen surfaces. In this paper we present a simple modification of a commercial confocal microscope to incorporate dark-field imaging. We discuss theoretical aspects of the resulting dark-field imaging mode and also give experimental examples.

Coloring Agents↗
PubMed1989

[High-frequency modulated positive pressure in the treatment of pneumopathies in premature infants].

The application of high frequency modulated continuous positive airway pressure (CPAP) into the airways by using a binasal cannula is described. High frequency oscillation of 15 Hz at amplitude depth of modulation of 15-25% of the overpressure value was modulated on the basic CPAP. The equipment used is described and some results obtained in using this therapy are presented. The frequency of spontaneous ventilation was decreased, PaO2 increased in the first hours of therapy, pH became rapidly normalized and clinical signs of respiratory distress were disappearing. The reported therapeutic method resulted in reduced mortality rate of immature infants.

High-Frequency Ventilation↗
PubMed1984

Embryotoxicity of 5-azacytidine in mice. Phase- and dose-specificity studies.

The agent 5-azacytidine, which directly affects nucleic acid metabolism, is a potent teratogen in NMRI mice. The establishment of general teratological data revealed clear-cut dose-response relationships after administration of this agent on either day 12 or day 14 of gestation. Inspection of skeletal abnormalities revealed a clear-cut phase specificity of this drug when administered on days 10 or 11 of pregnancy. Additional histological studies showed that central nervous system anomalies were induced mainly after administration of azacytidine on days 10, 11, 12, or 13 of pregnancy. A most conspicuous finding was the formation of anomalous glioblast islets within the ventricular zone covering the basal ganglia. The latter malformation mainly occurred after treatment on day 11 or 12 of pregnancy. Another important malformation syndrome was the appearance of capillary ectasias and hind paw hematomas, together with an intense necrotic cardiomyopathy after treatment on either day 11 or 12 of gestation.

Abnormalities, Drug-Induced↗