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Biomedical subjects

P Szabó

Publications and source records attributed to P Szabó.

At least 19 recordsLinked to original sources
PubMed2006

Sleep apnoea inducing hypoxemia is associated with early signs of carotid atherosclerosis in males.

The intima-media thickness (IMT) of carotid arteries as a marker of preclinical atherosclerosis was measured by ultrasonography in 49 subjects to determine, how strongly the obstructive sleep apnoea (OSA) syndrome is associated with atherosclerosis. Maximal IMT was higher in patients with cardiovascular diseases and with or without risk factors of atherosclerosis, presenting also OSA (apnoea-hypopnoea index=26.1+/-15.6/h) compared to controls without OSA (0.91+/-0.21 mm versus 0.77+/-0.18 mm, p<0.05). The prevalence of IMT > or = 0.85 mm was also higher in patients with cardiovascular pathology presenting OSA than without it (p<0.05). IMT(max) was increased in subjects with mild to moderate OSA alone (AHI=20.4+/-8.7/h) versus healthy controls (0.83+/-0.14 mm versus 0.63+/-0.08 mm, p<0.01). Regression analysis revealed a correlation of IMT(max) with the frequency, intensity and duration of intermittent hypoxemia reflected by AHI (p<0.01), minimal oxygen saturation (p<0.01) and time spent with Sa(O2) < 90% (p<0.05) in patients presenting OSA. The results indicate clear association between early signs of carotid atherosclerosis and moderate OSA in males with and without concomitant cardiovascular pathology.

Adult↗
PubMed2004

Anisotropies of the lower and upper critical fields in MgB2 single crystals.

The temperature dependence of the upper (H(c2)) and lower (H(c1)) critical fields has been deduced from Hall probe magnetization measurements of high quality MgB2 single crystals along the two main crystallographic directions. We show that Gamma(H(c2))=H(c2 axially ab)/H(c2 axially c) and Gamma(H(c1))=H(c1 axially c)/H(c1 axially ab) differ significantly at low temperature (being approximately 5 and approximately 1, respectively) and have opposite temperature dependencies. We suggest that MgB2 can be described by a single field dependent anisotropy parameter gamma(H) (=lambda(c)/lambda(ab)=xi(ab)/xi(c)) that increases from Gamma(H(c1)) at low field to Gamma(H(c2)) at high field.

Journal Article↗
PubMed2004

Mechanistic studies of dUTPases.

The essential enzyme dUTPase is responsible for preventive DNA repair via exclusion of uracil. Lack or inhibition of the enzyme induces thymine-less cell death in cells performing active DNA synthesis, serving therefore as an important chemotherapeutic target. In the present work, employing differential circular dichroism spectroscopy, we show that D. mel. dUTPase, a recently described eukaryotic model, has a similar affinity of binding towards alpha,beta-imino-dUTP as compared to the prokaryotic E. coli enzyme. However, in contrast to the prokaryotic dUTPase, the nucleotide exerts significant protection against tryptic digestion at a specific tryptic site 20 A far from the active site in the fly enzyme. This result indicates that binding of the nucleotide in the active site induces an allosteric conformational change within the central threefold channel of the homotrimer exclusively in the eukaryotic enzyme. Nucleotide binding induced allosterism in the D. mel. dUTPase, but not in the E. coli enzyme, might be associated with the altered hydropathy of subunit interfaces in these two proteins.

Allosteric Site↗
PubMed2002

A new phenanthridine alkaloid from Hymenocallis x festalis.

Investigation of the alkaloid fraction of the bulbs of Hymenocallis x festalis yielded a new natural product, 3-methoxy-8,9-methylenedioxy-3,4-dihydrophenanthridine (1). The structure was elucidated on the basis of spectroscopic data.

Alkaloids↗
PubMed2001

[Dual-energy x-ray absorptiometry and quantitative ultrasound bone density examinations in primary hyperparathyroidism].

The aim of this study was the analysis and comparison of bone density data obtained by dual-energy X-ray absorptiometry (DEXA) and quantitative ultrasound (QUS) and the follow up of bone density after parathyroidectomy of our patients with primary hyperparathyroidism. The authors performed bone mineral density (BMD) measurements using DEXA (Hologic QDR 4500 C) and QUS (Lunar Achilles Plus) devices in 22 patients with primary hyperparathyroidism between 1997 and 1999 (19 sporadic, 1 MEN 1., 2 MEN II.). Fifteen patients underwent parathyroidectomy (13 adenoma, 2 carcinoma). According to DEXA measurements all patients had osteoporosis. The lowest bone mineral density was detected at the wrist: the mean t-score was -4.00 +/- 1.79. After parathyroidectomy nine patients were followed for a mean of 12.8 months. After one year following surgery the most significant increase in BMD was 14.6%. The QUS values did not correlate with the DEXA data before the operation and no significant changes in stiffness were detected after surgery. The QUS values do not reflect the severity of the BMD decrease by DEXA in patients with primary hyperparathyroidism.

Absorptiometry, Photon↗
PubMed2001

Evidence for two superconducting energy gaps in MgB(2) by point-contact spectroscopy.

Experimental support is found for the multiband model of the superconductivity in the recently discovered system MgB(2) with the transition temperature T(c) = 39 K. By means of Andreev reflection, evidence is obtained for two distinct superconducting energy gaps. The sizes of the two gaps ( Delta(S) = 2.8 meV and Delta(L) = 7 meV) are, respectively, smaller and larger than the expected weak coupling value. Because of the temperature smearing of the spectra the two gaps are hardly distinguishable at elevated temperatures, but when a magnetic field is applied the presence of two gaps can be demonstrated close to the bulk T(c) in the raw data.

Journal Article↗
PubMed2001

Interlayer transport in the highly anisotropic misfit-layer superconductor [(LaSe)(1.14)](NbSe(2)).

The interlayer transport in a two-dimensional superconductor can reveal a peak in the temperature as well as the magnetic field dependence of the resistivity near the superconducting transition. The experiment was performed on the highly anisotropic misfit-layer superconductor [(LaSe)(1.14)](NbSe(2)) with T(c) of 1.2 K. The effect is interpreted within the tunneling mechanism of the charge transport across the Josephson-coupled layers via two parallel channels--the quasiparticles and the Cooper pairs. Similar behavior can be found in the high-T(c) cuprates but there it is inevitably interfering with the anomalous normal state. The upper critical magnetic field can be obtained from the interlayer tunneling conductance.

Journal Article↗
PubMed2001

[Eating disorders after the political changes in the formerly communist Eastern-European countries].

The authors summarize the Central and East European epidemiological data of eating disorders. These demonstrate that eating disorders are not exclusively characteristic to Western societies. In this respect the comparison of newer data to those which were performed before the political changes in 1989-1990 is especially valuable. Formerly in a Hungarian university sample the prevalence of bulimia was 1-1.3% among females, 0-0.8% among males, and this was higher than the prevalence of 0.6% in Austrian females, or 0% in German Democratic Republic. After the social changes similar data were found in several East European countries. This corroborates the culture-change idea of eating disorders. The transition to a Western market economy and the process of globalization is an experiment to evaluate the effect of sociocultural factors. The values and norms (e.g. thinness ideal) come closer to the Western culture, and mass media have a significant impact in this process.

Adolescent↗
PubMed1998

[Importance of endocrine imaging methods in multiple endocrine neoplasia type 2A proved by mutation analysis].

Multiple endocrine neoplasias are rare, inherited disorders. The authors describe a case history of a patient with multiple endocrine neoplasia type 2A, who presented with unusual clinical manifestations. The diagnosis of phaeochromocytoma, which was the first manifestation of the disorder, was greatly facilitated with radiologic imaging methods. The authors review, on the basis of recent data from the literature, the importance of radiologic methods, which improved due to methodological advance. Finally, the authors emphasize the importance of follow-up for early diagnosis.

Diagnostic Imaging↗
PubMed1998

Identification of oxytocin and vasopressin from neurohypophyseal cell culture.

Our observation that dispersed cultures of neurohypophysis obtained from adult rats are capable of synthesizing and releasing oxytocin and vasopressin is unexpected, because in whole animals these hormones are known only to be stored, not to be produced in the posterior lobe of the pituitary. The hormone content of cell culture medium was elevated from 0 to 129 +/- 14 pg/mg protein for oxytocin and from 0 to 42 +/- 4 pg/mg protein for vasopressin during two weeks as determined by specific radioimmunoassay. By molecular mass and structure determination (tandem mass spectrometry) we have proved that the supernatant of the cell cultures contains not only immunologically but mass spectrometrically identified neurohypophyseal hormones.

Animals↗
PubMed1996

Granulomatous hypophysitis associated with Takayasu's disease.

We report a case of Takayasu's disease, presenting with symptoms of fever, anaemia, elevated erythrocyte sedimentation rate, anterior pituitary failure and mild diabetes insipidus. A pituitary mass with suprasellar extension mimicking a pituitary adenoma was found, and histological examination revealed granulomatous hypophysitis. The diagnosis of Takayasu's disease was established after the development of a multiple arterial occlusive disease. We suggest that Takayasu's disease should be considered in the differential diagnosis of granulomatous hypophysitis of unknown origin.

Blood Sedimentation↗
PubMed1996

Mouse embryos with paternal duplication of an imprinted chromosome 7 region die at midgestation and lack placental spongiotrophoblast.

Imprinted genomic regions have been defined by the production of mice with uniparental inheritance or duplication of homologous chromosome regions. With most of the genome investigated, paternal duplication of only distal chromosomes 7 and 12 results in the lack of offspring, and prenatal lethality is presumed. Aberrant expression of imprinted genes in these two autosomal regions is therefore strongly implicated in the periimplantation lethality of androgenetic embryos. We report that mouse embryos with paternal duplication of distal chromosome 7 (PatDup.d7) die at midgestation and lack placental spongiotrophoblast. Thus, the much earlier death of androgenones must involve paternal duplication of other autosomal regions, acting independently of or synergistically with PatDup.d7. The phenotype observed is similar, if not identical to, that resulting from mutation of the imprinted distal chromosome 7 gene, Mash2, which in normal midgestation embryos exhibits spongiotrophoblast-specific maternally active/paternally inactive (m+/p-) allelic expression. Thus, the simplest explanation for the PatDup.d7 phenotype is p-/p- expression of this gene. We also confirm that PatDup.d7 embryos lack H19 RNA and posses excess Igf2 RNA as might be expected from the parental-specific activities of these genes in normal embryos.

Animals↗
PubMed1995

[Prevalence of clinical and subclinical forms of anorexia and bulimia nervosa among working females and males].

In a recent multicentre study it turned out that both clinical and subclinical eating disorders are more prevalent in Hungarian college students than among their Austrian and German counterparts. Now the prevalence of eating disorders was assessed in a population of Hungarian workers. From 1800 working females and males 762 returned the questionnaires; data of 689 subjects (571 females and 118 males) were analysed. Among females the prevalence rates of bulimia nervosa (according to DSM-III-R), subclinical bulimia nervosa and subclinical anorexia nervosa are 0.7% (n = 4), 5.3% (n = 30) and 0.7% (n = 4), respectively. In males two persons (1.7%) met DSM-III-R criteria for bulimia nervosa, three (2.5%) were identified as having subclinical bulimia nervosa and two (1.7%) subclinical anorexia nervosa. No case of clinical anorexia nervosa was found. So the overall prevalences of clinical and subclinical eating disorder syndromes are 6.7% for females and 5.9% for males in the working population. These disorders that mostly remain hidden in the population under study do not seem to be quite recent. These rather unfavorably high prevalence rates can be explained by the tendency for over-identification with Western norms and values; in addition, in the group of workers, the risk factors are supposed to be combined with the relative lack of protective factors.

Adolescent↗
PubMed1995

Identification of a nuclear factor-I family protein-binding site in the silencer region of the cartilage matrix protein gene.

Cartilage matrix protein (CMP) is synthesized by chondrocytes in a developmentally regulated manner. Here we have dissected promoter upstream elements involved in its transcriptional regulation. We show that although the 79-base pair CMP minimal promoter is promiscuous, 1137 base pairs of 5'-flanking region are capable of directing tissue- and developmental stage-specific transcription when fused to a reporter gene. This results from two positive control regions which, in proliferating chondrocytes, relieve the repression mediated by two non-tissue-specific negative control regions. Characterization of the promoter proximal silencer by DNase I footprinting and gel shifts revealed the presence of two elements, SI and SII, which bound mesenchymal cell proteins. Methylation interference analysis indicated a gapped palindromic binding site similar to nuclear factor I (NF-I) family proteins within SI, but only a half-site within SII. Gel shift assays with specific NF-I and mutated SI competitors, binding of recombinant NF-I, as well as supershift analysis with NF-I-specific antiserum verified the binding of NF-I family proteins to the SI element. Double-stranded SI and SII oligonucleotides inserted in single copy in either orientation were found to repress both homologous and heterologous promoters upon transfection into mesenchymal cells. Transcriptional repression also occurred when a consensus NF-I site itself was fused to the CMP minimal promoter. We conclude that NF-I-related protein(s) can mediate transcriptional repression in cells of mesenchymal origin.

Animals↗
PubMed1995

Prevalence of eating disorders and minor psychiatric morbidity in central Europe before the political changes in 1989: a cross-cultural study.

The prevalence of culture-bound syndromes such as eating disorders in the countries of Central and Eastern Europe is unclear and comparative epidemiological studies are lacking. Before the political changes in 1989 we therefore investigated eating disorders, eating attitudes and psychological health in two Eastern European countries and in one Western democracy. A total of 1225 female and male medical students in Hungary, the German Democratic Republic (GDR) and Austria were surveyed. The instruments included the Eating Disorder Inventory and the GHQ. The prevalence of eating disorders was calculated on the basis of simulated DSM-III-R diagnosis. In females, bulimia nervosa prevalence rates of 0.6% (95% CI 0.02, 3.46), 1% (0.2, 2.95) and 0% (0, 2.07) were calculated for Austria, Hungary and the GDR, respectively. For subclinical bulimia nervosa, the rate for Hungary (3.8%; 1.95, 6.72) was twice as high as for Austria (1.9%; 0.39, 5.5) and the GDR (1.7%; 0.36, 4.88). Hungarian subjects indicated more psychiatric 'caseness' than their GDR or Austrian counterparts. We conclude that eating disorders represented at least as common a problem in Eastern as Western Europe before the changes in political organization. This may be due to an identification process with Western values. A further increase of eating disorders in these countries induced by the recent changes may be possible.

Adult↗
PubMed1995

Expression of the cartilage matrix protein gene at different chondrocyte developmental stages.

Cartilage matrix protein (CMP), a major noncollagenous component of certain types of hyaline cartilage, is synthesized by chondrocytes in a developmentally regulated manner. In this study, we monitored the accumulation of CMP in the developing chicken limb and sternum by immunostaining. In older embryos, the specific extracellular staining was restricted to the resting/proliferative zone of metaphyseal cartilage and to the immediately adjacent hypertrophic cartilage. A lack of staining was observed in the peripheral layers of articular cartilage. Data were compared with the accumulation of CMP mRNA measured by Northern analysis relative to other cartilage-specific messages in cell cultures representing different stages of chondrocyte differentiation, as well as with the steady state mRNA levels in tissue samples. We found a correlation between the gene expression pattern of the in vitro cultures and the one observed in certain in vivo differentiation stages. The high-density mesenchyme culture was utilized as a model for studying the events at early stage I (stage Ia) of chondrogenesis. This culture was characterized by relatively low steady state mRNA levels for cartilage proteins, including the later activation of the CMP gene as compared to type II collagen or link protein genes, and relatively high steady state mRNA levels for type VI collagen and beta-actin. Chicken embryo chondrocyte cultures obtained from sterna of 14-day-old embryos, however, consisted predominantly of stage Ib chondrocytes, and showed high steady state levels for cartilage proteins, but relatively lower levels for type VI collagen and beta-actin mRNAs. In accordance with the in vivo data, a relatively high steady state level was detected for CMP mRNA in cultures of hypertrophic (stage II) chondrocytes. We also performed transient expression assays in the various culture systems to study the role of the promoter upstream and intronic control regions in the tissue- and developmental stage-specific regulation of the CMP gene. We showed that the enhancer worked in a lineage-specific manner, by further stimulating the minimal promoter activity independent of the developmental stage of chondrocytes, while it did not in other tissues. The promoter upstream control regions, however, seemed to play a role in restricting the promoter activity to a certain chondrocyte developmental stage.

Animals↗