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Biomedical subjects

G Bakó

Publications and source records attributed to G Bakó.

At least 19 recordsLinked to original sources
PubMed1998

Heterogeneous signal pathways through TSH receptors in porcine thyroid cells following stimulation with Graves' immunoglobulin G.

OBJECTIVE: We compared different signal transduction pathways through thyroid stimulating hormone receptor (TSH-R) in porcine thyroid cells (PTC) following stimulation with thyroid stimulating hormone (TSH) and 11 thyroid stimulating immunoglobulin samples (TSI) obtained from patients with Graves' disease. DESIGN: Following stimulation with TSI, the level of inositol trisphosphate (IP3) and [Ca2+]i, as well as the membrane bound protein kinase C (PKC) activity and the intensity of the arachidonic acid (AA) cascade, were determined in PTC. RESULTS: Seven out of eleven TSI samples activated PTC through IP3 generation, elevated [Ca2+]i from the intracellular pools, exhibited verapamil-insensitive membrane-bound PKC activation, and enhanced release of [14C]AA derivates (however, one of the samples was also able to take up Ca2+ from the extracellular space). Four out of eleven TSI samples did not activate the phospholipase C (PLC) system in which case the Ca2+ signal occurred only in the presence of extracellular Ca2+, the membrane bound PKC activation was verapamil sensitive, and in two of these four TSI samples, the AA release was extremely high. CONCLUSIONS: The simultaneous examination of the majority of the known signal pathways using TSI samples showed that TSI samples from different patients activate thyroid cells through different pathways. Their effects differ from that of TSH and, to a certain extent, from each other. The results give a certain new insight into the intracellular mechanisms exerted by TSI.

Adult↗
PubMed1992

[A strategy for the diagnosis of thyroid function].

The characteristics of thyroid function tests are analysed. The author stress the importance of the right strategy for investigating thyroid function in the view of expenses, labor and time consuming tests. The guidelines of American Thyroid Association for use of laboratory tests are presented. Finally there is published another investigating protocol, which can be applied for our domestic situations.

Humans↗
PubMed1991

Late results of thyroid surgery for hyperthyroidism performed in childhood.

The authors report on the complex follow-up of 60 patients operated on for hyperthyroidism in childhood, on average 13.7 years after surgery. In 16.7% of the patients manifest hypothyroidism, in 45% subclinical hypothyroidism was found; 30% of the patients were euthyroid, and manifest hyperthyroidism recurred in 8.3%. Autonomous adenomas were enucleated in two children and three young adults. Severe disorders in thyroid function developed especially after the surgery of diffuse toxic goiters accompanied by ophthalmopathy. The disorders of humoral and cellular immunity were detected most frequently in recurrent manifest hyperthyroidism. There was no case where ophthalmopathy progressed after the operation. In the offspring of the operated patients the incidence of hyperthyroidism was not increased in childhood. The authors call attention to the importance of postoperative follow-up and hormone treatment.

Adenoma↗
PubMed1990

[Rheologic investigation of electrode gels. III. Study of temporal changes of gel structure].

In the publication consisting of 3 parts nine electrode gels have been investigated siú of them are used in hospital pharmacies of this country. Character and stability of gel structure have been studied and controlled by rheological methods. Structural forces have been numerically characterized with maximum and equilibrium viscosity, values of "M and B coefficients" and directional tangents of viscosity curves. Mechanical and thermal stability have been determined, changes for six months storing have been studied by means of all rheological parameters, respectively. Besides investigating rheological parameters electric conductivity values--which are important in respect of practical use of electrode gels--have been determined too. On the basis of results Carbopol "G" designated gel has been found to be the best its use has been proposed not only in supersonic tests but also in ECG.

Electrocardiography↗
PubMed1989

[Bone scintigraphy in uremic osteodystrophy].

99mTc-HEDP bone scan was carried out on 12 long-time haemodialysed patients, suffering from bone pains. X-ray examinations of the bone and laboratory tests (serum calcium, -phosphor, -alkaline phosphatase, -parathormone, -aluminium, -ferritin) were also performed. The scintigrams were evaluated by two semiquantitative scores. Based on diffuse, increased radiopharmacon uptake of the bones and more than five points in the Fogelman score 5 patients most likely had serious and 3 had moderate hyperparathyroidism. In two patients osteomalacy was presumed based on decreased radiopharmacon uptake of the bones, increased uptake of the soft tissues and zero Fogelman score. Mixed or other bone disease was suggested in two other patients. Good correlation was found between the results of bone scans, the parathormone values and the results of histology obtained after parathyreoidectomy of 4 patients and autopsy of two others. This non-invasive examination (ie. bone scan) is helpful in differential diagnosis of uraemic osteodystrophy and its wide use is proposed in domestic nephrological practice.

Adult↗
PubMed1989

Euthyroid infiltrative ophthalmopathy: clinical-immunological characteristics.

The thyroid hormone titres of the sera of 25 euthyroid infiltrative ophthalmopathic patients was examined, TRH test was performed, and thyroid-stimulating antibodies were studied by membrane receptor assay and TRAK assay. Previously, other diseases causing exophthalmos could be excluded by ophthalmological, radiological examinations, orbital ultrasonography and/or CT. Following TRH administration, 18 out of 25 patients showed abnormal TSH response, 16 of them were TSI - positive. Five of them became hyperthyroid 2-2.5 years later. After TRH administration 7 patients produced normal TSH response, none of them became hyperthyroid in the subsequent 2-4 years follow-up period. In the 7 TRH-negative patients, four were found to have higher hTG and an antithyroid microsome antibody titre. In those patients the fine needle biopsy verified chronic lymphocytic thyroiditis. In three patients there was no evidence of a pathological change of the thyroid gland. Based on our results, the patients could be divided into three groups. The prognostic and therapeutic differentiation of these groups seems to be justified.

Adult↗
PubMed1989

[Rheologic investigation of electrode gels. II. Mechanical and thermal stability].

In the publication consisting of 3 parts nine electrode gels have been investigated six of them are used in hospital pharmacies of this country. Character and stability of gel structure have been studied and controlled by rheological methods. Structural forces have been numerically characterized with maximum and equilibrium viscosity, values of "M and B coefficients" and directional tangents of viscosity curves. Mechanical and thermal stability have been determined, changes for six months storing have been studied by means of all rheological parameters, respectively. Besides investigating rheological parameters electric conductivity values--which are important in respect of practical use of electrode gels--have been determined too. On the basis of results Carbopol "G" designated gel has been found to be the best its use has been proposed not only in supersonic tests but also in ECG.

Electrochemistry↗
PubMed1989

A non-isotopic screening test for antibodies to TSH receptor: dot immunobinding assay.

A dot immunobinding assay (DIBA) for thyrotropin (TSH) receptor antibodies is described. The method depends on the detection of antibody binding to highly purified thyroid plasma membrane attached to nitrocellulose solid support by horse-radish peroxidase - conjugated anti-human IgG. The method can detect down to 0.75 mU LATS standard and 1/1000 dilution of Graves' serum or immunoglobulin fraction. The interaction is inhibited dose-dependently by bTSH but not by insulin or human chorionic gonadotropin. The DIBA results show close correlation to those of TRAK (TBII) but not to cyclic AMP generation assay. DIBA is reproducible when tested monthly for 4 months. Sera and immunoglobulins gave virtually the same results. The method has a sensitivity of 90%, validity of 90% and specificity of 80% for both. We have, thus developed a sensitive and reliable method for screening for TSH receptor antibodies which can be performed in routine clinical laboratories.

Animals↗
PubMed1985

The significance of thyroid-stimulating antibody (TSAb) in the management and prognostic evaluation of Graves disease.

Sixty six patients with Graves disease were followed up for the presence of TSAb at intervals of 4 to 12 weeks. Three different assays, the competitive TSH membrane-receptor assay (MRA), the cAMP-assay and the colloid droplet assay (CD) were used in parallel for demonstration of the antibody. In 17 of the patients TSAb was demonstrable also during remissions. 11 of these patients relapsed within a year. TSAb-positivity decline 1 to 4 months after 131I treatment. In case of persisting TSAb positivity 131I therapy or surgery should be given preference to thyrostatic medication. In gravidae followed up for TSAb, positivity not only persisted throughout pregnancy but even increased during the last trimester. After delivery all patients relapsed. One of the gravidae died of pregnancy toxicosis, the infant of another woman was thyrotoxic at birth. In pregnant women who have Graves disease and are positive for TSAb, thyrostatic or surgical treatment is recommended after the 2nd trimester even in cases of minor severity.

Adolescent↗
PubMed1985

Photoaffinity labelling of the porcine thyrotropin receptor--effect of Graves' immunoglobulin G and anti-TSH anti-idiotypic antibodies.

Despite active investigations, the structure of the thyrotropin (TSH) receptor, its organization and its interaction with putative anti-receptor antibodies remains unknown. We have undertaken photoaffinity cross-linking of TSH-binding sites on porcine thyroid plasma membranes with 125I-bTSH and the photoactive heterobifunctional cross-linker, N-hydroxysuccinimidyl-4-azidobenzoate. In the presence of reductant a single Mr 58,600 band was labelled, whereas 3 distinct bands (Mr 192,400, 86,000 and 59,600) were visualized when photolysed samples were subjected to sodium dodecyl sulphate polyacrylamide gel electrophoresis under non-reducing conditions. The intensities of these labelled bands were quantitatively decreased with increasing concentrations of native bTSH, but not by large amounts of insulin or human chorionic gonadotropin. Graves' disease IgG and an anti-TSH anti-idiotype IgG, both of which are putative anti-receptor antibodies, caused different inhibition patterns on non-reduced gels: anti-TSH anti-idiotype predominantly inhibited the labelling of the Mr 192,400 band (probably the holoreceptor), whereas Graves' IgG also inhibited labelling of lower M.W. bands. Both antibodies had much less influence, of the Mr = 58,600 band resolved in the presence of reductant.

Affinity Labels↗
PubMed1983

Both TSH and thyroid-stimulating antibody of Graves' disease bind to an Mr 197,000 holoreceptor.

Human and porcine thyroid plasma membranes were submitted to sodium-dodecyl sulphate polyacrylamide gel electrophoresis in the absence and presence of reductant and electrotransferred onto nitrocellulose paper. Native bovine TSH, IgG from all 10 patients with active Graves's disease tested, as well as rabbit anti-bTSH anti-idiotypic antibody were found to bind to a single Mr approximately 197,000 band present only in non-reduced gels. We conclude that TSH and Graves' IgG bind to the TSH holoreceptor.

Animals↗