Biomedical subjects

G Deák

Publications and source records attributed to G Deák.

At least 19 recordsLinked to original sources

PubMed2005

Serum 25(OH)-vitamin D levels and bone metabolism in patients on maintenance hemodialysis.

AIMS: An increasing amount of evidence suggests that 25-hydroxy vitamin D3 (25(OH)D3) may contribute to the bone health of patients with chronic kidney disease (CKD). The underlying vitamin D status of these patients, however, has often been neglected. In a cross-sectional study we assessed the association between vitamin D status and parathyroid function, bone turnover, bone mass and structure in patients on maintenance hemodialysis. METHODS: 69 patients on maintenance hemodialysis were assessed by bone densitometry (DEXA) and quantitative bone ultrasound (QUS). Serum 25-hydroxy vitamin D3 levels, serum markers of bone turnover and clinical data were tabulated. RESULTS: A high prevalence of potentially significant vitamin D3 deficiency was found in this patient group: 59% of the patients had a 25(OH)D3 level below 20 nmol/l. There was a significant negative correlation between serum 25(OH)D3 levels and serum intact parathyroid hormone (iPTH) (r = -0.231, p < 0.05), and this association remained significant after controlling for potential covariables. Furthermore, we show here that serum 25(OH)D3 concentration is positively correlated with bone mineral density (BMD) measured at the radius (r = 0.424, p < 0.01). Finally, we show for the first time that 25(OH)D3 levels are significantly and independently correlated with broadband ultrasound attenuation (beta = 0.262, p < 0.05) measured with calcaneal quantitative bone ultrasound (QUS) in patients with chronic renal failure. CONCLUSION: Vitamin D3 deficiency may contribute to the impaired bone health of patients on maintenance dialysis.

Absorptiometry, Photon↗

PubMed2001

[Fibro-osseous lesion of the central nervous system].

The case of a 53-year-old woman with headache and progressive right sided decline of visual acuity is reported. Computed tomography scans of the brain revealed multiple circumscribed foci of mineralization located over the left frontal and parietal, as well as the right central brain parenchyma. Surgical sampling of the left frontal lesion yielded a conglomerate composed of mineralized vessels, myriad of psammoma bodies, and metaplastic lamellar bone entangled within poorly cellular collagen fibers. No evidence was found of an underlying vascular malformation or tumor, nor was there evidence of parenchymal necrosis of infectious origin. On account of the organoid association of the mesenchymal elements and the mineralized moiety, the lesion was consistent with fibro-osseous lesion of the central nervous system. Also known as "calcifying pseudotumor" of the brain, the origin of this exceedingly rare condition is, as yet, unknown. By analogy, its pathogenesis is likely to involve mechanisms underlying tumoral calcinosis of soft tissues.

Bone and Bones↗

PubMed2001

Interaction between iron(II) and hydroxamic acids: oxidation of iron(II) to iron(III) by desferrioxamine B under anaerobic conditions.

Interaction between iron(II) and acetohydroxamic acid (Aha), alpha-alaninehydroxamic acid (alpha-Alaha), beta-alaninehydroxamic acid (beta-Alaha), hexanedioic acid bis(3-hydroxycarbamoyl-methyl)amide (Dha) or desferrioxamine B (DFB) under anaerobic conditions was studied by pH-metric and UV-Visible spectrophotometric methods. The stability constants of complexes formed with Aha, alpha-Alaha, beta-Alaha and Dha were calculated and turned out to be much lower than those of the corresponding iron(II) complexes. Stability constants of the iron(II)-hydroxamate complexes are compared with those of other divalent 3d-block metal ions and the Irving-Williams series of stabilities was found to be observed. Above pH 4, in the reactions between iron(II) and desferrioxamine B, the oxidation of the metal ion to iron(III) by the ligand was found. The overall reaction that resulted in the formation of the tris-hydroxamato complex [Fe(HDFB)]+ and monoamide derivative of DFB at pH 6 is: 2Fe2+ + 3H4DFB+ = 2[Fe(HDFB)]+ + H3DFB-monoamide+ + H2O + 4H+. Based on these results, the conclusion is that desferrioxamine B can uptake iron in iron(III) form under anaerobic conditions.

Journal Article↗

PubMed2001

Fragmentation study of rutin, a naturally occurring flavone glycoside cationized with different alkali metal ions, using post-source decay matrix-assisted laser desorption/ionization mass spectrometry.

A post-source decay matrix-assisted laser desorption/ionization mass spectrometric (PSD-MALDI-MS) study of rutin, a naturally occurring flavone glycoside cationized with different alkali metal ions, is reported. The fragmentations of rutin were performed by selecting the [R + Cat]+ peaks for PSD, where R represents a rutin molecule and Cat an alkali metal ion (Li+, Na+, K+). The PSD-MALDI mass spectra showed, depending on Cat, different fragmentation patterns with respect to both the quality and quantity of the fragment ions formed. The intensity of fragmentation decreased in the order Li+ > Na+ > K+. The fragmentation mechanism and an explanation for the observed differences are suggested.

Cations↗

PubMed2001

Copper(I) chloride: a simple salt for enhancement of polystyrene cationization in matrix-assisted laser desorption/ionization mass spectrometry.

The possibility of using copper(I) chloride as a doping salt to enhance the cationization of polystyrene in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) was investigated. It was shown that copper(I) chloride possesses sufficient solubility in tetrahydrofuran. The parameters of the MALDI mass spectra of different polystyrene samples, such as the number-average (M(n)) and mass-average (M(w)) molecular mass values, obtained by copper(I) cationization were compared with those obtained by means of silver(I) cationization, and good agreement was found. It was also shown that application of copper(I) chloride as a doping salt, and dithranol as a matrix, ensured good MALDI mass spectra of the sample spots even after storage for 1 month.

Journal Article↗

PubMed2001

[Application possibilities of dynamic laser light scattering photometry for the examination of poly(ethylene glycol) suppositories].

Status epilepticus is one of the most common neurologic emergencies in children, adolescents, and young adults. The advantage of diazepam suppository in medicinal therapy appears mainly in treatment of childhood epilepsy. A hydrophilic suppository base was investigated in solution by dynamic light scattering and results were compared to those of the membrane diffusion experiments measuring diazepam solubilization. According to the dynamic laser light scattering photometric measurements, the good solubilization effect of the macrogol mixture (5% Polysorbatum 20, 10% Macrogolum 400, 85% Macrogolum 1540) is explained by the formation of small, tight micellas. As the Polysorbatum 20 tenside resulted in the significant decrease (p < 0.05) of the formation of great micellas, its use led to the formation of small, tight, almost monodisperse micellas of 40-50 nm in the aqueous solution of the macrogol mixture.

Diazepam↗

PubMed2000

Silver Nanoparticles by PAMAM-Assisted Photochemical Reduction of Ag(+).

The photochemical synthesis of Ag(0) nanoparticles in the presence of amino- and carboxylate-terminated PAMAM dendrimers is reported. The formation of Ag(0) nanoparticles was followed spectrophotometrically and by transmission electron microscopy (TEM). According to TEM investigations Ag(0) nanoparticles with the average size of about 7 nm in diameter were produced. Based on the present investigation a possible mechanism for the Ag(0) nanoparticles formation is proposed. Copyright 2000 Academic Press.

Journal Article↗

PubMed1997

[Arrhythmogenic right ventricular cardiomyopathy associated with multiple right atrial thrombi].

The authors report the case of an arrhythmogen right ventricular cardiomyopathy. The disease is characterised by the partial or total loss and the fibro-fatty replacement of right ventricular musculature and by the higher familiar incidence. The clinical importance of the disease is the malignant ventricular arrhythmia generated in the right ventricular wall, that is often fatal. Right heart failure is less frequent and develops mainly preterminally. The curiosity of this case is right atrial and ventricular thrombi diagnostized concomitantly with progressive heart failure. This combination is a rarity in medical literature, in contrast with the disease itself, as it was previously supposed. Early diagnosis, pharmacological and non-pharmacological treatment can reduce the fatal outcome.

Adult↗

PubMed1995

The effects of task comprehension on preschoolers' and adults' categorization choices.

In experimental tasks in which subjects sort sets of objects with conflicting appearances and taxonomic relations, preschoolers often have been found to categorize according to appearance. The procedures used in past studies, however, may have biased preschoolers to attend to appearance instead of taxonomic relations. This possibility was examined in two experiments. In Experiment 1, children's preference for taxonomic- or appearance-based sorting was affected by both the training and the instructions they received. Adults in Experiment 1 were affected by instructions, but not by training. In Experiment 2 preschoolers sorted above chance according to the criterion for which they received training and instruction (taxonomic relations or appearance). Consistency data, children's justifications, and spontaneous labeling support the conclusions that training and instructions have a significant effect on children's preference to sort according to taxonomic relations or appearance, and that both criteria can be used systematically by children as young as four. Implications for task comprehension, flexibility, methodology, and education are discussed.

Adult↗

PubMed1993

[Pseudophaeochromocytoma (hypertensive crisis as a result of beta receptor hypersensitivity?)].

The diagnosis of phaeocromocytoma could be excluded in a 57 year-old man suffering from "typical" hypertensive paroxysms by using modern standardized technics. The presented disorder which has been named pseudophaeochromocytoma may include different pathogenetical entities. In the observed case the background of the disorder was thought to be "beta-receptor hyperresponsiveness" which has been confirmed by the determination of the urinary catecholamine excretion as well as by the introduction of a new isoproterenol infusion method. In response to beta-blocking agents (which are contraindicated in phaeochromocytoma) no further hypertensive crises occurred, resulting in a dramatic improvement of the patient's condition.

Adrenal Gland Neoplasms↗

PubMed1993

Effect of the natural bioflavonoid antioxidant silymarin on superoxide dismutase (SOD) activity and expression in vitro.

The in vitro effects of the bioflavonoid antioxidant silymarin on the expression and activity of superoxide dismutase (SOD) enzyme was studied in erythrocytes and lymphocytes from patients with chronic alcoholic liver disease. In vitro incubation with the agent in a concentration corresponding to the usual therapeutic dosage markedly increased the SOD expression of lymphocytes as measured by flow-cytofluorimetry following staining with monoclonal anti-Cu/Zn-SOD antibody and FITC-conjugated anti-mouse Ig, as well as erythrocyte and lymphocyte SOD activities. The data indirectly suggest that antioxidant activity might be one of the important factors in the hepatoprotective action of this bioflavonoid.

Adult↗

PubMed1992

[Long-term phenytoin (Diphedan) therapy leading to IgA nephropathy].

A single case of IgA nephropathy with a concomitant tubulointerstitial nephritis, developing during a long-term phenytoin therapy is reported. The prolonged phenytoin therapy did neither prevent the transitional increases of serum IgA level nor ward off deterioration of the histological alterations. This case suggests that acute tubulointerstitial nephritis may have played a role in the mesangial trapping of IgA immunocomplexes.

Adult↗

PubMed1991

[Perioperative myocardial infarct].

Retrospective analysis has been carried out with the surgical material of 9 years in the wards of surgical character of a county hospital to determine the incidence and main clinical characteristics of perioperative myocardial infarction. Data of 61 patients were processed in order to answer the questions. Age, arteriosclerosis causing disturbance of organ perfusion and the change of blood pressure in the perioperative period play the main role in the development of this complication of high mortality. Detailed clarification of the coronary state before the elective operation, a possible aortocoronary bypass operation appear to prevent most effectively the pathological picture.

Adult↗

PubMed1991

Effect of the bioflavonoid silymarin on the in vitro activity and expression of superoxide dismutase (SOD) enzyme.

Superoxide dismutase activity and expression of the erythrocytes and lymphocytes of patients suffering from chronic alcoholic liver disease and those of healthy controls were investigated after in vitro incubation with silymarin. It was concluded that silymarin treatment in a concentration achievable by in vivo treatment (10 micrograms/ml) significantly increased the SOD activity of both the erythrocytes and lymphocytes of patients with liver disease, whereas the SOD expression of the lymphocytes enhanced to a considerable extent. These results indirectly indicate that the scavenger silymarin is able to increase the antioxidant protection of the cells by ameliorating the deleterious effects of free radical reactions.

Adult↗

PubMed1990

[Immunomodulator effect of silymarin therapy in chronic alcoholic liver diseases].

The effects of the hepatoprotective, antioxidant drug silymarin (Legalon) on some cellular immune parameters of patients with histologically proven chronic alcoholic liver disease were studied in a six month double blind study. The lectin induced proliferative activity of the lymphocytes got enhanced, the originally low T cell percentage and the originally high CD8+ cell percentage have been normalized, the antibody-dependent and natural cytotoxicity of the lymphocytes decreased during silymarin therapy. All these changes were significant, while in the placebo group no significant changes occurred, except for a moderate elevation of the T cell percentage. Thus, the immunomodulatory activity of silymarin might be involved in the hepatoprotective action of the drug and improves the depressed immunoreactivity of the patients.

Adjuvants, Immunologic↗

PubMed1990

[Effect of silimarin (Legalon) therapy on the antioxidant defense mechanism and lipid peroxidation in alcoholic liver disease (double blind protocol)].

A double blind study. Antioxidant and antiperoxidative effects of the free radical scavenger agent silymarin (Legalon) were investigated in patients with chronic alcoholic liver disease in a double blind clinical trial. Six month treatment (at a daily dose of 420 mg) with silymarin significantly enhanced the originally low superoxide dismutase activity of erythrocytes and lymphocytes and also restored the diminished superoxide dismutase expression on lymphocytes as measured by flow-cytofluorimetry. In addition, silymarin therapy markedly increased the serum level of ree--SH groups and the activity of glutathione peroxidase. In contrast, a considerable fall in serum malondialdehyde concentration was detected in patients having received silymarin. However, in case of placebo-treated patients the above mentioned parameters of antioxidant defense system and lipid peroxidation failed to change significantly. These data indirectly suggest that antioxidant, antiperoxidative effects might be important factors in the mechanism of hepatoprotective action of silymarin.

Double-Blind Method↗

PubMed1990

Primary spinal intramedullary malignant lymphoma. A case report.

A rare case of primary malignant intramedullary lymphoma, localized in the cervical part of the spinal cord, is presented. The onset of clinical symptoms was associated with herpes zoster infection. Surgery led to the histological diagnosis. The clinical investigations excluded the presence of lymphoma in other sites in the central nervous system and in the extraneural organs. Postoperative irradiation and chemotherapy effected relict of neurological symptoms.

Female↗

PubMed1990

Immunomodulatory and hepatoprotective effects of in vivo treatment with free radical scavengers.

The hepatoprotective and immunomodulatory effects of silymarin and amino-imidazol-carboxamid-phosphate were studied in 60 patients with compensated alcoholic cirrhosis of the liver in a one month double blind clinical trial. Treatment with both drugs normalized the elevated levels of aspartate aminotransferase, alanine aminotransferase and serum bilirubin, markedly reduced the high level of gamma-glutamyl transferase, increased lectin-induced lymphoblasttransformation, decreased the percentage of CD8+ cells and suppressed lymphocytotoxicity. None of these changes occurred in the placebo-treated group. Thus the hepato-protective effects of silymarin and amino-imidazol-carboxamid-phosphate are accompanied by changes in parameters of cellular immunoreactivity of the treated patients.

Adjuvants, Immunologic↗