Biomedical subjects

E Berényi

Publications and source records attributed to E Berényi.

At least 19 recordsLinked to original sources

PubMed2001

Brain water and proton magnetic resonance relaxation in preterm and term rabbit pups: their relation to tissue hyaluronan.

The present study was performed to investigate simultaneously total brain water, T1 and T2 relaxation times, and hyaluronan (HA) in fetal and neonatal rabbits. Attempts were also made to establish the relationship of HA to total brain water and to T2-derived motionally distinct water fractions, since HA is known to bind water and to limit tissue water mobility. Experiments were carried out in fetal Pannon white rabbit pups at gestational ages of 25, 27, 29, and 31 days and at a postnatal age of 4 days. The brain tissue water content (desiccation method), T1 and T2 relaxation times (H1-NMR method), and HA concentration (radioassay HA 50) were measured, and free and bound water fractions were calculated by using multicomponent fits of the T2 relaxation curves. Compared with values in newborn pups, water and HA contents were found to be highly elevated in the preterm brain and decreased markedly during early postnatal life. The trends and time courses of T1 and T2 relaxation times proved to be similar, but the postnatal decrease in T2 was preceded by a significant decline in late gestation. Maturity-related changes occurred in the T2 relaxation derived bound water fraction which amounted to 4-19% of brain water. The bound water fraction appeared to be independent of total brain water and HA concentration, and HA is, therefore, unlikely to be the only factor controlling brain water mobility. The clear dissociation of bound water fraction from total water suggests restructuring of brain water during the perinatal period.

Animals↗

PubMed2000

[Chiari I. malformation, a new childhood disease?].

From July 1, 1994 to July 1, 1997 a total of 17 children with Chiari I malformation diagnosed by MRI was seen in our hospital. Six of them underwent craniocervical decompression and tonsilar resection. The major complaints of all these children were gait ataxia and persisting (longer than 6 month) headache, and one child had acutely presenting vertigo and problem of swallowing. The MRI showed that in all cases the tonsils were displaced below the level of CI. Hydrocephalus or syrinx was not seen. At surgery the tonsils were resected. All the patients can be considered cured and symptom free at an average follow up of 13 month.

Arnold-Chiari Malformation↗

PubMed2000

[Dynamic MR examination of the breast--histological correlations].

The authors outline dynamic MR mammography (dMRM) as a highly sensitive diagnostic method for the examination of the breast. In a retrospective study relating to 84 processed cases, in the knowledge of the cytological-histological findings the diagnostic accuracy of the examinations was determined. The role of the method in detecting benign and malignant changes of the breast has been estimated. Misdiagnosed cases have been analysed and recommendations for the application of the method are included. The MR proved to be positive in 32 cases and negative in 3 cases of the analysed 35 malignant tumors. Benign lesions were found at microscopy in 49 cases, of which MR correctly diagnosed 40. The sensitivity and the specificity of dynamic MR mammography were 91% and 82%.

Breast Diseases↗

PubMed2000

[Refsum disease].

For the first time in literature the authors interpret the pathography of Refsum's disease, in the case of their patient, as pseudo-hypervitaminosis A. The biochemical basis of the clinical picture is a defect in the activity of phytanic-acid-alpha-hydrolase belonging to the peroxisomal system. As a consequence, phytanic acid accumulates in the serum and in the parenchymal tissues. Retinol, an alcohol with high molecular weight, is a natural ligand of nuclear RXR (retinoid-X-receptor), which plays an important role in the regulation of peroxisoma synthesis. In Refsum's disease the phytanic acid accumulated because of the enzyme defect competes with the biotransformation derivates (all-trans-retinoic acid, 9-cis-retinoic acid) of the all-trans-retinol (vitamin A) for the nuclear RX receptor binding sites, and as a very potent receptoractivator it causes the intestinal symptoms of hypervitaminosis A. The authors review the procedure of fatty-acid chromatography necessary for the establishment of the diagnosis and discuss--in addition to dietary restrictions--recent therapeutic possibilities, like plasmapheresis, cascade filtration, lipapheresis and oral batylalcohol treatment.

Child, Preschool↗

PubMed2000

Lung water and proton magnetic resonance relaxation in preterm and term rabbit pups: their relation to tissue hyaluronan.

The present study was performed to investigate simultaneously total lung water, T(1) and T(2) relaxation times, and hyaluronan (HA) in preterm and term rabbits. Attempts were also made to establish the relationship of HA to total lung water and to T(2)-derived motionally distinct water fractions. Experiments were performed in fetal Pannon white rabbit pups at gestational ages of 25, 27, 29, and 31 d and at a postnatal age of 4 d. Lung tissue water content (desiccation method), T(1) and T(2) relaxation times (H(1)-NMR method), and HA concentration (radioassay) were measured, and free and bound water fractions were calculated by using multicomponent fits of the T(2) relaxation curves. Lung water content and T(1) and T(2) relaxation times were highest at a gestational age of 27 d and then declined steadily during the whole study period. Similar trends and time courses were seen for the fast and slow components of the T(2) relaxation curve. The T(2)-derived free water fraction remained unchanged at a gestational age of 25-29 d ( approximately 67%), but increased progressively to a value of 78.5 +/- 7.9% at 31 d (p < 0. 001) and to 83.4 +/- 9.4% at the postnatal age of 4 d (p < 0.01). Opposite changes occurred in the bound water fraction. Lung HA concentration decreased with advancing gestation from 870.8 +/- 205.2 microg/g dry weight at 25 d to 162.6 +/- 32.4 microg/g dry weight at 31 d (p < 0.001), but it was increased 2-fold postnatally. HA correlated positively with total lung water (r = 0.39; p < 0.001) but not with the bound water fraction. It is suggested that the physiologic lung dehydration is associated with macromolecule-related reorganization of lung water and that the role of HA in this process needs to be further investigated.

Aging↗

PubMed1999

Brain adaptation to water loading in rabbits as assessed by NMR relaxometry.

The present study was undertaken to investigate the cerebral adaptation to hypoosmolar stress in adult Pannon white rabbits by applying proton nuclear magnetic resonance relaxometry. Progressive hyponatremia was induced by combined administration of hypotonic dextrose in water and 8-deamino-arginine vasopressin over a hydration period of 3, 24, and 48 h. Each group comprised five animals. After completing the hydration protocols, blood was taken to determine plasma osmolality (freezing point depression) and sodium concentration (ion-selective electrode) and, at about the same time, T2-weighted images were made. After the in vivo measurements, the animals were killed and brain tissue samples were obtained to measure water content (desiccation method) and T1 and T2 relaxation times (proton nuclear magnetic resonance method). Free and bound water fractions were calculated by using multicomponent fits of the T2 relaxation curves. It was shown that brain water content and T1 relaxation time remained unchanged despite the progressing hyponatremia. By contrast, T2 relaxation time increased steadily from the control value of 100.2 +/- 7.7 ms to attain its maximum of 107.5 +/- 8.5 ms (p < 0.05) after 48 h of hydration. Using biexponential analysis, fast and slow components of the T2 relaxation curve could be distinguished that corresponded to the bound (T21) and free (T22) water fractions. In response to hyponatremia, the bound water fraction was markedly depressed from 6.5 +/- 3.0% to 3.6 +/- 0.9% (3 h, p < 0.05) and 3.9 +/- 0.8% (24 h, p < 0.05); then it approached the initial value of 5.3 +/- 2.5% by the end of the hydration period of 48 h. It is concluded that restructuring of brain water is a contributory factor to the successful adaptation to hypotonic environment.

Adaptation, Physiological↗

PubMed1998

Water content and proton magnetic resonance relaxation times of the brain in newborn rabbits.

The present study, using proton nuclear magnetic resonance relaxation (H1 NMR) measurements, was undertaken to quantitate water fractions with different mobility in the brain tissue obtained form New Zealand White rabbit pups. Serial studies were carried out at the postnatal age of 0-1, 24, 48, 72, and 96 h in pups nursed with their mothers and suckling ad libitum (group I) and in those pups separated from their mothers and completely withheld from suckling (group II). Tissue water content (desiccation method) and T1 and T2 relaxation times (H1 NMR method) were measured. Free, loosely bound, and tightly bound water fractions were calculated by applying multicomponent fits of the T2 relaxation curves. It was demonstrated that brain water content and T1 and T2 relaxation times did not change with age in the suckling pups. In pups withheld from suckling brain water decreased from 89.4 +/- 0.5% at birth to 87.7 +/- 0.1% at the age of 96 h (p < 0.05), T1 remained unchanged, and there was a significant fall in T2 by the age of 72 h (188 +/- 12 versus 178 +/- 4 ms, p < 0.05) and 96 h (171 +/- 6 ms, p < 0.01). Partition of brain water into bound and free fractions as derived from biexponential fits of T2 decay curve showed that the percent contribution of bound water fraction in pups of group I fell progressively from 61% at birth to 3% at the age of 72-96 h (p < 0.05). This fall was accelerated by the complete deprival of fluid intake, and the level of about 4% could be attained as early as the age of 24 h. Triexponential analysis of T2 relaxation curves revealed that the loosely bound fraction (middle component) predominated over the free (slow component) and the tightly bound (fast component) water fractions. In response to withholding fluid intake, the free water fraction increased 4-fold at the expense of tightly bound brain water. It is concluded that the majority of neonatal brain water is motion-constrained. The free, the loosely bound, and the tightly bound water fractions appear to be interrelated; from the brain water store water can be released to supply free water for volume regulation.

Age Factors↗

PubMed1998

In vivo assessment of breast muscle, abdominal fat and total fat volume in meat-type chickens by magnetic resonance imaging.

Measurements were performed on commercial broiler chickens by magnetic resonance imaging (MRI) tomography. A total of 72 chickens were scanned at the age of 6, 7, 8, 10, 16 and 20 weeks. MRI scans based on spin echo sequence were taken in the three orthogonal planes. The volume of the pectoral muscles increased from 259 cm3 to 1035 cm3 in males and from 250 cm3 to 875 cm3 in females between 6 and 20 weeks of age. Abdominal fat volume increased from 18.9 cm3 to 153.2 cm3 in males and from 19.3 cm3 to 267.0 cm3 in females between 7 and 20 weeks of age. Total body fat volume increased from 129 cm3 to 557 cm3 in males and from 171 cm3 to 1321 cm3 in females between 6 and 20 weeks of age. The correlation coefficients between the total volume of fat pixels and the amount of abdominal fat determined in the coronal plane by MRI were 0.85 and 0.95 in the male and female sex, respectively. Changes found in the pectoral muscles (mm. pectorales) as well as in total and abdominal fat volume were in close agreement with dissection data obtained at the slaughterhouse and with laboratory data based on the measurement of total body chemical composition in both sexes. This MRI method can be a good complement to computed tomography (CT) scanning in the transversal plane.

Adipocytes↗

PubMed1997

[Method and use of intracranial cine MR imaging].

The authors introduce a dynamic, non-invasive MR method for the examination of liquorspaces and liquor flow in 221 patients. This method is suitable not only for a dynamic imaging of liquor-flow but also for the semi-quantitative evaluation of flow through the aqueduct. This later measurement can help to select the shuntresponsive NPH cases as well. Cine MR examination along with the routine protocol seems to be most helpful in the differential-diagnostics of different hydrocephalus cases.

Humans↗

PubMed1997

[Principles of functional MRI imaging and its possibilities in the study of cerebral cortex activation].

While MR imaging of anatomic structures has long been widely appreciated, the emergence of functional magnetic resonance imaging (FMRI) methods for localising brain activity has emerged in the beginning of the 90s. This new MRI technique produces images of activated brain regions by detecting the indirect effects of neural activity on local blood volume, flow and oxygen saturation, and it is a promising new tool for further understanding of the relationships among brain structure, function and pathology. The information revealed by FMRI is partially overlapping with PET and SPECT, but it is non-invasive and has a better spatial and temporal resolution. The authors briefly summarise the concept and basics of FMRI and demonstrate the first successful FMRI examination performed in Hungary. The potential role of FMRI in the clinical practice is presented.

Animals↗

PubMed1996

Nuclear magnetic resonance relaxation parameters of muscle in malignant hyperthermia-susceptible swine.

RATIONALE AND OBJECTIVES: The malignant hyperthermia (MH) syndrome involves characteristic changes in metabolism that have a significant effect on the postmortem properties of muscle tissue. We investigated the 1H nuclear magnetic resonance (MR) relaxation parameters of muscle tissue from normal (MH-) and malignant hyperthermia-susceptible (MH+) swine taken before their death to identify whether postmortem metabolic differences would be accompanied by changes in relaxation parameters. METHODS: Muscle samples from 63 MH-susceptible swine were characterized by proton MR relaxation times (T1 and T2). The water content, pH, conducting, and the "subjective meat" quality were assessed in order to differentiate the meat into one of three groups: normal, pale-soft-exudative, and dark-firm-dry. RESULTS: The T2 relaxation of MH- and MH+ muscles was significantly different, but no significant changes were detected in the water content and corresponding T1 relaxation times. CONCLUSION: These data suggest that MH-susceptible swine can be distinguished from normal swine using nuclear MR relaxometry. The results of relaxation measurements and the multiexponential analysis of the T2 curves suggest a shift between the different water compartments during MH that might predict the increased water loss of muscle tissue after death.

Animals↗

PubMed1996

Postnatal changes in water content and proton magnetic resonance relaxation times in newborn rabbit tissues.

In the present study, using proton nuclear magnetic resonance relaxation (H1 NMR) measurements, an attempt was made to quantitate water fractions with different mobility in the skin, skeletal muscle, and liver tissues obtained from New Zealand white rabbit pups. Serial studies were carried out at the postnatal age of 0-1, 24, 48, and 72 h in pups nursed with their mothers and suckling ad libitum (group I) and in those pups separated from their mothers and completely withheld from suckling (group II). Tissue water content (desiccation method) and T1 and T2 relaxation times (H1 NMR method) were measured. Free, loosely bound, and tightly bound water fractions were calculated by applying multicomponent fits of the T2 relaxation curves. It was demonstrated that skin water content and T1 and T2 relaxation times decreased with age (p < 0.01), the decrease in T2 proved to be more pronounced in group II than in group I (p < 0.05). Muscle and liver water, and T1 and T2 relaxation times did not change with age in the suckling pups. In response to with-holding fluid intake muscle water remained constant, liver water increased paradoxically (p < 0.05). T1 relaxation time showed no consistent change in either tissues, whereas T2 relaxation time decreased significantly (muscle, p < 0.01) or tended to decrease (liver, p < 0.06). Using biexponential analysis fast and slow components of T2 relaxation curve could be distinguished that corresponded to the bound and free water fractions. Bound water accounted for 42-47%, 50-57%, and 34-40% of total tissue water in the skin, skeletal muscle, and liver, respectively, regardless of age and fluid intake. Triexponential fits of the T2 relaxation curve made possible the further partition of tissue water into tightly bound (fast component), loosely bound (middle component), and free (slow component) water fractions. In all tissues studied, loosely bound fraction predominated (skin, 48-64%; muscle, 54-65%; liver, 45-63%), followed by the free (skin, 26-45%; muscle, 23-32%; liver, 20-25%) and the tightly bound water fraction (skin, 6-14%; muscle, 10-16%; liver, 14-33%). Postnatal age and fluid intake had no apparent influence on this pattern of distribution. It is concluded that the majority of neonatal tissue water is motion-constrained. The free, the loosely bound, and the tightly bound water fractions appear to be interrelated and dependent on age, fluid intake, the tissues studied, and their hydration.

Animals↗

PubMed1996

[The Hungarian nifedipines].

The short history of the nifedipine drug substance containing Cordaflex product family--produced by EGIS Pharmaceuticals Ltd.--is presented.

Calcium Channel Blockers↗

PubMed1993

Relationship between cellular ATP, potassium, sodium and magnesium concentrations in mammalian and avian erythrocytes.

Intracellular K+/Na+ ratios of erythrocytes of various mammalian species are known to differ markedly. We have measured ATP, K+, Na+, Mg2+, H2O contents of erythrocytes of twelve mammalian and three avian species. Our results indicate that the intracellular ATP concentration in erythrocytes of different species is in close positive correlation with the K+/Na+ ratios (linear correlation coefficient, r = 0.852). Furthermore, ATP levels in erythrocytes of individual sheep with different potassium concentrations correspond with their K+/Na+ ratios (r = 0.747). Intracellular magnesium concentrations also correlate with ATP concentrations in erythrocytes of different species (r = 0.629) and in different sheep (r = 0.549).

Adenosine Triphosphate↗

PubMed1993

[The benzodiazepine story].

Benzopyrylium salt (3) was converted by means of excess of hydrazine hydrate into a substance of a composition C22H26N2O4. The structure of this compound was elucidated by means of detailed NMR and mass-spectroscopic studies and the structure of 1-(3,4- dimethoxyphenyl)-5-ethyl-7,8-dimethoxy-4-methyl-5H-2,3-benzodiazepine (4) has been proved. Conformation analysis was performed as well and it has been established that two conformers (A and B) exist in reversible equilibrium. The molecule contains a chiral centre and the enantiomers were separated via optical resolution. Two different 14C-labelled 4 were prepared for pharmacological studies. The compound is known as GrandaxinR in the medicinal practice (INN = tofisopam).

Anti-Anxiety Agents↗

PubMed1990

Comprehensive epidemiological and clinicopathological survey of Hodgkin's disease in Hungary.

To determine the epidemiological pattern and some clinicopathological features of Hodgkin's disease in Hungary, the data of 233 consecutive patients with the disease from seven counties, diagnosed between January 1983 and July 1987, were analysed on the basis of data from four cancer centers. Large variations were noted in incidence rates between the different regions of Hungary. The epidemiological pattern seems to vary from those reported in developed and developing countries. A sharp rise in the incidence of Hodgkin's disease occurred at the end of the second decade of patients' lives. More of our Hodgkin's patients are at advanced clinical stages, with systemic symptoms and a histological type of mixed cellularity, at the time of diagnosis, than in the western hemisphere. On the average, there is a 6-month period between the appearance of the first sign or symptom and the diagnosis. There is a lack of data outlining the epidemiological differences in the pattern of Central Europa. The aim of this study is to supply data for the etiopathogenetic research of Hodgkin's disease, as there is an important task to improve the unfavourable home situation, and to strive for earlier diagnosis in this disease.

Adolescent↗

PubMed1989

Factors of the extrinsic pathway of blood coagulation in tumour associated macrophages.

Despite the growing evidence implicating intratumoural fibrin formation in the progression of malignant tumours, the origin of coagulation factors that participate in extravascular clotting has not been elucidated. Using immunohistochemical methods we attempted to detect and localize clotting factors of extrinsic pathway in different human malignant tumours. Coagulation factors II, V, VII and X (FII, FV, FVII and FX) were detected in a huge number of cells showing spindle-shaped or stellate morphology. By double immunohistochemical labellings it was demonstrated that cells containing these clotting factors express monocyte/macrophage differentiation marker antigens recognized by Leu M3, Ki M7 and DAKO-macrophage monoclonal antibodies, i.e. they represent monocyte-derived, phagocytic tumour associated macrophages (TAMs). These findings suggest that TAMs can be viewed as clot cells, which in addition to the initiation of extravascular clotting by expressing procoagulant activity can also provide all the components necessary for the extrinsic thrombin formation.

Animals↗

PubMed1989

[Management of vomiting induced by polychemotherapy in Hodgkin's disease].

Sixty patients with Hodgkin's disease were treated with a polychemotherapy regimen including very emetic dacarbazine and adriamycin in addition to bleomycin and vincristine on 622 treatment days during the last 10 years. Nausea in 97% and severe vomiting in 91% were observed during the treatment causing considerable distress to patients which led to patient noncompliance in 26.6%. Among the used antiemetic agents haloperidol was less active than high-dose metoclopramide alone or with high-dose methylprednisolone which were extremely effective. The control and prevention of drug-induced emesis is a major problem for cancer patients and their oncologists. The present situation and the home tasks are also discussed on the basis of literature and their observations.

Antiemetics↗