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Biomedical subjects

I Szabó

Publications and source records attributed to I Szabó.

At least 19 recordsLinked to original sources
PubMed2002

Color Doppler ultrasonography in the differentiation of uterine sarcomas from uterine leiomyomas.

OBJECTIVE: The aim of this study was to investigate uterine vascularity in cases of uterine leiomyomas and uterine sarcomas, as well as to determine the efficiency of uterine blood flow analysis in differentiating between them. MATERIALS AND METHODS: Transvaginal color and pulsed Doppler findings obtained from 117 patients with histologically proven uterine leiomyoma and 12 with uterine sarcoma were retrospectively assessed. RESULTS: The mean intratumoral resistance index (RI) and pulsatility index (PI) were significantly lower and the intratumoral peak systolic velocity (PSV) was significantly higher in patients with sarcomas than in patients with uterine leiomyomas. Marked reduction of RI and PI and increased PSV could be found in 14 of the leiomyoma cases which showed large size and/or necrotic, degenerative and inflammatory changes. When a cut-off value of 0.5 for the RI was considered, the detection rate for uterine sarcoma was 67% and the false-positive rate was 11.8%. CONCLUSION: These results suggest that the intratumoral RI detected by color and pulsed Doppler ultrasonography in themselves could be poor for the preoperative differential diagnosis of uterine sarcoma.

Adult↗
PubMed2002

Occurrence of osteopenia among adolescent girls with oligo/amenorrhea.

The occurrence of reduced bone mineral density (BMD) among adolescent girls with oligomenorrhea or secondary amenorrhea, due to 'pure' dysfunction of the hypothalamo-pituitary-ovarian (HPO) axis (without anorexia nervosa, excessive sport or ballet, slimming diet, etc.) was examined. The study group consisted of 19 adolescent girls (age 16-18 years) with oligo/amenorrhea. Clinical (height, weight, age at menarche, duration of amenorrhea, body mass index (BMI)), hormonal (follicle stimulating hormone (FSH), luteinizing hormone (LH), estradiol, progesterone, testosterone, prolactin), and ion (calcium, sodium, potassium, phosphate, chloride) parameters and the BMD of the lumbar spine were investigated. Correlations between BMD and other parameters were also examined. Twenty healthy volunteers (same age and regular cycles) served as controls. Three girls had osteoporosis, with a BMD below -2 standard deviations (SD). Ten showed osteopenia, with a BMD value between -1 and -2 SD. Only six of the study group had a normal BMD within +/- 1 SD. A positive correlation was observed between the BMD and the BMI (r = 0.73; p < 0.05). All the controls had normal hormonal, ion and BMD parameters. 'Pure' dysfunction of the HPO axis in adolescents, causing oligomenorrhea or secondary amenorrhea, might result in reduced BMD and, consequently, lower peak bone mass. Treatment of menstrual cycle disorders is necessary for the prevention of osteoporosis.

Adult↗
PubMed2002

Thrombophilic markers in patients with congenital bleeding disorders.

We have studied the presence or absence of thrombophilic markers in 59 patients with congenital bleeding disorders. Theoretically, the coexistence of coagulation factor deficiency and thrombophilia in patients with haemophilia may cause the bleeding tendency to decline. In 8 cases we have found thrombophilic marker positivity, in 7 patients APC resistance and in 1 patient protein S deficiency has been revealed. The presence of thrombophilic markers did not affect the frequency of bleeding episodes or the development of haemophilic arthropathy. The factor concentrate utilization, however, was lower in the group carrying thrombophilic markers, which indicates that the bleeding episodes were less severe. Relying on the strength of these findings, the medicinal influencing of inhibitor mechanisms may present itself as a potential therapy.

Activated Protein C Resistance↗
PubMed2001

Family 7 cellobiohydrolases from Phanerochaete chrysosporium: crystal structure of the catalytic module of Cel7D (CBH58) at 1.32 A resolution and homology models of the isozymes.

Cellobiohydrolase 58 (Cel7D) is the major cellulase produced by the white-rot fungus Phanerochaete chrysosporium, constituting approximately 10 % of the total secreted protein in liquid culture on cellulose. The enzyme is classified into family 7 of the glycosyl hydrolases, together with cellobiohydrolase I (Cel7A) and endoglucanase I (Cel7B) from Trichoderma reesei. Like those enzymes, it catalyses cellulose hydrolysis with net retention of the anomeric carbon configuration. The structure of the catalytic module (431 residues) of Cel7D was determined at 3.0 A resolution using the structure of Cel7A from T. reesei as a search model in molecular replacement, and ultimately refined at 1.32 A resolution. The core structure is a beta-sandwich composed of two large and mainly antiparallel beta-sheets packed onto each other. A long cellulose-binding groove is formed by loops on one face of the sandwich. The catalytic residues are conserved and the mechanism is expected to be the same as for other family members. The Phanerochaete Cel7D binding site is more open than that of the T. reesei cellobiohydrolase, as a result of deletions and other changes in the loop regions, which may explain observed differences in catalytic properties. The binding site is not, however, as open as the groove of the corresponding endoglucanase. A tyrosine residue at the entrance of the tunnel may be part of an additional subsite not present in the T. reesei cellobiohydrolase. The Cel7D structure was used to model the products of the five other family 7 genes found in P. chrysosporium. The results suggest that at least two of these will have differences in specificity and possibly catalytic mechanism, thus offering some explanation for the presence of Cel7 isozymes in this species, which are differentially expressed in response to various growth conditions.

Amino Acid Sequence↗
PubMed2001

The application of cross-point switch arrays as input selector switch devices for multi-channel electrophysiological experiments.

Integrated circuits (ICs) containing cross-point switch arrays were applied to create analog input selector switch devices for multi-channel electrophysiological experiments. The described analog input selector switch devices make it possible to connect to the main amplifier's inputs those microelectrode and preamplifier output wires that yield unit discharges of acceptable shape and amplitude, or yield other kind of acceptable electrophysiological signals (EEG, EP). This kind of selector allows to use higher number of preamplifier channels and to ignore the input channels without adequate signals or the channels with noisy inputs. No manual switching is required, as the work is done by computer controlled switches. The switch positions can be saved and reloaded at the next experimental session through an I/O port (e.g. the parallel port) of the computer.

Amplifiers, Electronic↗
PubMed2001

N-Alkane uptake and utilisation by Streptomyces strains.

Streptomyces strains isolated from the Kuwait Burgan oil field were defined as S. griseoflavus, S. parvus, and S. plicatus utilised n-hexadecane, n-octadecane (purified fractions of mineral oil), kerosene, and crude oil as sole carbon and energy sources. The strains were incubated with n-alkanes and increase of the fatty acid content with chain length equivalent to the employed n-alkanes was observed. Signal transducing GTP-binding proteins (GBPs) play an important role in n-alkane uptake in streptomycetes. Specific activators of GBPs increased the uptake of hydrocarbons. Using the hydrophobic fluorescent dye diphenylhexatrien (DPH) as a probe, it was found that the microviscosity of the hydrophobic inner region of the cellular membrane is significantly lower in hydrocarbon utilisers than in non-utilisers. This difference probably reflects differences in the fatty acid composition of the strains. When cultures were grown in n-alkane containing media, electron microscopy revealed that the hydrocarbon utilisers showed less-electron dense areas as inclusions in the cytoplasm. Soil samples inoculated with Streptomyces strains eliminated hydrocarbons much faster than those not containing these strains, serving as control. When inorganic medium was supplied with n-hexadecane-1-14C as sole carbon and energy source, radioactive CO2 was detected. Since streptomycetes have not been used until now for oil elimination, though they are known as abundant soil bacteria tolerating extreme conditions, their possible use for bioremediation of hydrocarbon contaminated soils is discussed.

Alkanes↗
PubMed2001

Comparative analysis of cyclin D1 and oestrogen receptor (alpha and beta) levels in human leiomyoma and adjacent myometrium.

The aim of these experiments was to investigate the expression of cyclin D1 and of oestradiol receptors as well as the level of [(3)H]oestradiol binding in leiomyoma and adjacent myometrium from human uteri at different menstrual phases and at an early stage of menopause. [(3)H]oestradiol binding was determined by saturation analysis, while the oestradiol receptor (ER) alpha and beta and cyclin D1 levels were determined by Western blot analysis of 16 samples of human leiomyomas and corresponding myometria at different hormonal stages. In leiomyomas during all phases of the menstrual cycle, ERalpha expression, high affinity oestradiol binding and cyclin D1 expression were all elevated in comparison with adjacent myometrium. ERbeta expression and low affinity oestradiol binding were enhanced in leiomyomas only during the proliferative phase. During menopause, ERbeta expression and low affinity binding were enhanced in leiomyomas, while the ERalpha expression was not significantly enhanced and cyclin D1 levels were similar to that in myometrium. Only the oestradiol binding exhibited any menstrual cycle-related changes. Our data suggest the involvement of cyclin D1 in the growth of leiomyomas during the menstrual cycle. In menopause, there appears to be a switch from ERalpha to ERbeta expression in leiomyomas, and the induction of cyclin D1 is decreased. The regression of tumour may ensue from these changes at menopause.

Adult↗
PubMed2001

Assessment of myometrial and cervical invasion of endometrial cancer by transvaginal sonography.

INTRODUCTION: The aim of this study was to determine the efficiency of transvaginal ultrasonography in the assessment of myometrial invasion and cervical involvement (preoperative staging) of endometrial cancer. MATERIALS AND METHODS: Transvaginal ultrasonography was performed on 52 women to classify endometrial cancer with respect to myometrial invasion and cervical involvement according to the International Federation of Gynaecologists and Obstetricians recommendations for surgical staging of endometrial cancer. Endometrial cancer was diagnosed on the basis of dilatation and curettage and the degree of invasion was evaluated preoperatively by transvaginal ultrasonography. Ultrasonographic findings were compared to the surgical staging and histopathology of the surgical specimen. RESULTS: Myometrial invasion evaluated by transvaginal sonography was accurate in 46 of 52 cases (accuracy 88%, sensitivity 86%, specificity 90%, positive predictive value 92%, negative predictive value 83%). Tumor extension to the cervix was properly diagnosed in seven of ten women in which it was present. CONCLUSION: Transvaginal ultrasonography is a reliable method for assessing myometrial invasion and cervical involvement. This non-invasive method should be included as an important tool in the establishment of individualized treatment programs for women with endometrial cancer.

Adult↗
PubMed2001

Kallmann's syndrome: pregnancy through intracytoplasmic sperm injection and complicated by gestational diabetes.

Kallmann's syndrome is characterized by hypogonadotropic hypogonadism and anosmia. Assisted reproductive techniques such as intracytoplasmic sperm injection (ICSI) may be required to treat the infertile couple with oligozoospermia. Rare complications have been described in patients with Kallmann's syndrome, but gestational diabetes has not previously been reported. A case of Kallmann's syndrome with infertility is reported. Ovulation was successfully induced by human menopausal gonadotropin therapy, but pregnancy could not be achieved by artificial insemination or by conventional in vitro fertilization, although the husband had only moderate oligozoospermia. A high fertilization rate of the retrieved oocytes and successful pregnancy was achieved by ICSI. The pregnancy was complicated by gestational diabetes that was managed by insulin therapy. Successful ovulation induction in Kallmann's syndrome is not rare, but ICSI may be needed in selected cases. Some recent data have suggested that diabetes may occur in patients with Kallmann's syndrome, but further investigation is needed to establish whether gestational diabetes is associated with Kallmann's syndrome or is purely coincidental.

Adult↗
PubMed2000

[Parvovirus B19 infection in hydrops fetalis].

In a retrospective study from 210 foetal autopsies carried out in a period between 1992 and 1999 fifteen hydropic foetuses were found. The cause of the hydrops was shown to be Rh incompatibility in one case only. The cause of hydrops was not discernible in one case. In the others pathological examination clarified the cause and pathomechanism of non-immune hydrops. One isolated cystic hygroma, one monochorionic twin pregnancy with twin to twin transfusion, one case of sacrococcygeal teratoma and 4 cases of congenital heart diseases were reported. Postmortem interphase cytogenetic examination showed X0 monosomy in 2 cases. In further 4 foetuses pathognomic viral inclusions in the proerythroblasts raised the probability of parvovirus B19 infection what was confirmed by immunohistochemistry and electronmicroscopic examination. The occurrence of the parvovirus B19 associated cases of foetal hydrops was shown to be higher (4/15) in this series than in the literature. The accumulation of cases in 1998 is suggestive of an outbreak. The prenatal diagnostic implications and the attempts on further management are also discussed.

Adult↗
PubMed2000

[Ovulation induction therapy and malignant ovarian cancer].

In the authors' institute 1097 patients received treatment for ovarian cancer between the 1st of January, 1960 and the 31st of December, 1997. 92 of them had malignant granulosa cell tumor. In this study the link between ovulation induction therapy and ovarian cancer was analyzed with retrospective questionnaire. 236 questionnaires were shared out among patients with malignant ovarian tumor, who were treated between 1990 and 1997. 7 of 113 patients, who gave correct answers to the questions (6.2%) received ovulation induction therapy. Epithelial ovarian cancer developed in 2 of the cases during, and in 5 cases just 6-16 years after the clomiphene-citrate treatment. None of the 45 patients with granulosa cell tumors received induction therapy. The number of patients admitted because of malignant ovarian tumor before and after the induction therapy was also compared. There was no significant increase in the occurrence of the malignancy. Since 1986 in the in vitro fertilization program of the clinic nearly 1,500 patients were treated with effected ovulation induction drugs causing superovulation. The authors don't know of any development of malignant ovarian tumor, and 732 woman have confirmed this fact. The number of patients deceased in consequence of ovarian cancer in different age groups, and the distribution of the women population in every age group in Hungary, from the year of 1979 was also analyzed. There was no significant increase found in the number of deceased among the studied age groups, moreover a significant decrease among them could be observed. The link between ovulation induction therapy and ovarian cancer can neither be strengthen, nor deny by the result of the study, however the close relationship which seemed to be logical can be queried. To give an exact answer for the question a vast, long-term, prospective of retrospective follow-up case-control study is needed.

Adult↗
PubMed2000

Extramitochondrial porin: facts and hypotheses.

Mitochondrial porin, or VDAC, is a pore-forming protein abundant in the outer mitochondrial membrane. Several publications have reported extramitochondrial localizations as well, but the evidence was considered insufficient by many, and the presence of porin in nonmitochondrial cellular compartments has remained in doubt for a long time. We have now obtained new data indicating that the plasma membrane of hematopoietic cells contains porin, probably located mostly in caveolae or caveolae-like domains. Porin was purified from the plasma membrane of intact cells by a procedure utilizing the membrane-impermeable labeling reagent NH-SS-biotin and streptavidin affinity chromatography, and shown to have the same properties as mitochondrial porin. A channel with properties similar to that of isolated VDAC was observed by patch-clamping intact cells. This review discusses the evidence supporting extramitochondrial localization, the putative identification of the plasma membrane porin with the "maxi" chloride channel, the hypothetical mechanisms of sorting porin to various cellular membrane structures, and its possible functions.

Animals↗
PubMed2000

Allergenicity of major cow's milk and peanut proteins determined by IgE and IgG immunoblotting.

BACKGROUND: Specific IgG antibodies are frequently observed in food-allergic patients. However, the allergen-fraction specificity of IgG antibodies in relation to IgE antibodies is not well defined. Our aim was to determine the IgE and IgG antibody profile to major cow's milk and peanut-antigen fractions in food-allergic patients and tolerant individuals. METHODS: Sera were collected from 10 patients allergic to cow's milk and 10 patients allergic to peanuts, as well as from 20 control subjects. Cow's milk and peanut proteins were migrated on SDS-PAGE and immunoblotted for IgE, IgG, and IgG4 antibodies. Food-specific IgE concentrations were measured by CAP System FEIA, and IgG and IgG4 concentrations by ELISA. RESULTS: In food-allergic children, similar fraction-specific IgE, IgG, and IgG4 antibody-binding profiles to the major cow's milk or peanut antigens were found. In nonallergics, the presence of fraction-specific IgG antibodies was mostly dependent on regular ingestion of the food. The presence of specific antibody on immunoblots correlated with their quantitative measurement. The mean value for specific IgE in cow's milk-allergic patients was 450 +/- 1,326 IU/ml, and 337 +/- 423 IU/ml in peanut-allergic patients. Specific IgG antibody values in milk-allergic patients were not different (median OD 1.5, range 0.3-2.3) from controls (median OD 1, range 0.2-1.8). However, in peanut-allergic patients, IgG concentrations were significantly higher than in controls (OD 1.2 [0.5-1.3] vs 0.5 [0.3-0.7]; P< 0.01). CONCLUSIONS: Similar fraction-specific IgE and IgG antibody profiles in allergic individuals suggest a common switching trigger involving both isotypes. Intrinsic allergenicity might explain identical IgG antibody fraction specificity in nonallergics and in allergics. The presence of IgG antibodies in nonallergics was related to regular ingestion of the food.

Adolescent↗
PubMed2000

A synthetic gamma-lactone group with beta-lactamase inhibitory and sporulation initiation effects.

Previous studies showed that some lactones have beta-lactamase inhibitory or antibacterial effects, others--like A-factor (a gamma-butyrolactone) and its derivatives--stimulate sporulation in Streptomyces griseus strains. Our experiments were aimed at exploring whether synthetic gamma-lactones had such effects. None of the seven gamma-lactones studied showed antibacterial activity, but two of them inhibited beta-lactamases isolated from various bacteria. These two gamma-lactones did not reduce colony formation of murine bone marrow cells in vitro, indicating that they were not toxic to proliferating mammalian cells. Four gamma-lactones, including the two inhibiting beta-lactamase, stimulated sporulation in the non-sporulating S. griseus bald 7 mutant. Further studies of gamma-lactones as potential inhibitors of beta-lactamase seem to be warranted.

Animals↗
PubMed2000

Hormonal and clinical effects of chronic gonadotropin-releasing hormone agonist treatment in polycystic ovary syndrome.

The aim of the study was to evaluate the hormonal (focusing on the urinary steroid profile) and clinical effects of chronic gonadotropin-releasing hormone (GnRH) agonist treatment in patients with polycystic ovary syndrome (PCOS) suffering from hirsutism. A long-acting GnRH agonist was administered for 6 months in eight PCOS patients. Hormonal effects were measured by determining serum luteinizing hormone (LH), follicle stimulating hormone (FSH), prolactin, testosterone and estradiol concentrations, and by profiling urinary steroids using capillary gas chromatography of 24-hour urine samples. To evaluate 5 alpha-reductase enzyme activity, the ratios of androsterone to etiocholanolone and 5 alpha-tetrahydrocortisol to tetrahydrocortisol were calculated in urine samples. The ratio of androgen to cortisol metabolites was also determined before, and 3 and 6 months after therapy. LH and estradiol levels were suppressed significantly after the first injection and testosterone after the second injection of the GnRH agonist. Thus, serum testosterone was normalized. Ratios of urinary steroids reflecting 5 alpha-reductase enzyme activity (androsterone to etiocholanolone and 5 alpha-tetrahydrocortisol to tetrahydrocortisol) and the ratio of androgen to cortisol metabolites decreased significantly after 3 months of treatment. Degree of hirsutism, assessed by Ferriman-Gallwey score, diminished after 6 months, but not significantly. In conclusion, our data show that long-acting GnRH agonist treatment of PCOS patients is effective in reducing serum and urinary androgen levels, but it is not accompanied by an effective reduction in hirsutism during a 6-month treatment period. A longer or a combined treatment would be needed to achieve significant improvement in hirsutism. Gas chromatographic profiling of urinary steroids and the use of specific ratios of the excreted metabolites seems to be a sensitive tool both in the diagnosis of PCOS and in monitoring ovarian suppression.

Adult↗
PubMed2000

Apoptosis in the gastric mucosa: molecular mechanisms, basic and clinical implications.

Apoptosis a programmed cell death, is an essential mechanism of eliminating damaged or aged cells and thus to maintain tissue integrity. There are two central pathways that lead to apoptosis: a) the positive induction by ligands (death factors) binding to plasma membrane receptors (death factor receptors) and b) negative induction by the loss of suppressor activity. The common execution mechanisms of apoptosis consist of the activation of cytosolic aspartate-specific proteases (ICE-proteases) termed caspases, which can be activated via various intracellular pathways. In the stomach, mucosal surface epithelial cells are constantly exfoliating to the gastric lumen and completely replaced within 3-5 days under physiological conditions. Apoptosis has been reported to take place in all regions of the stomach with apoptotic cells occurring predominantly in the superficial parts of the gastric glands, at a rate of 2-3% for all cells. Following mucosal injury (e.g. ulcer development), apoptosis rapidly increases and remains elevated for 2-3 months. In a 3-month old ulcer scar, the apoptosis rate of mucous, parietal, chief and endocrine cells was found to be similar to that of normal gastric mucosa. Helicobacter pylori (H. pylori) infection induces apoptosis in the gastric mucosa and this action appears to be independent of VacA cytotoxin of H. pylori strains. Nonsteroidal anti-inflammatory drugs (NSAIDs), especially cyclooxygenase-2 (COX-2) inhibitors are potent inductors of gastric epithelial cell apoptosis. However, they can abrogate apoptosis or proliferation effects induced by H. pylori. Many details of the exact intracellular and molecular mechanisms regulating apoptosis in gastric mucosa remain to be elucidated.

Animals↗