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Biomedical subjects

E Varga

Publications and source records attributed to E Varga.

At least 55 records · Page 3Linked to original sources
PubMed1996

Induction of renin release from isolated glomeruli by inorganic mercury(II).

Mercury(II) ions are known to accumulate in the kidney and their effect upon the renin-angiotensin system has also been described. The question, however, whether mercury(II) also exerts direct effect on the juxtaglomerular cells (JGC) to induce renin release remained to be answered. Suspension of isolated glomeruli was used to measure the mercury(II)-induced renin release in vitro. The glomeruli were isolated from female BALBc mice. HgCl2 was found to be capable of inducing renin release directly from JGC. The effect is concentration-dependent (P < 0.05, r = 0.914 and P < 0.01, r = 0.982, with and without Neutral Red vital staining) and becomes apparent already at a mercury(II) ion concentration as low as 1 microM. The renin-releasing effect of the mercury ion is to be inhibited by dithiothreitol (DTT) (renin activity 20.37 vs. 2.60 ng/ml.h in supernatant) as well as the elevated osmotic concentration of the incubating bath medium (20.37 vs. 6.84 ng/ml.h). This suggests that certain membrane sulfhydryl groups are implicated in the process on the one hand, and it is also in accordance with the known sensitivity of the renin granules to osmotic pressure on the other hand. Light and electron micrographs also demonstrate the direct, effective role of Hg(II) in the renin release process. Therefore, it is assumed that apart from its influence on tubulo-glomerular feedback a direct way of action of mercury(II) on renin release must also be taken into account.

Animals↗
PubMed1996

The strength of iliosacral lag screws and transiliac bars in the fixation of vertically unstable pelvic injuries with sacral fractures.

This study compares the relative strengths of iliosacral lag screws and transiliac bars in the fixation of vertically unstable pelvic injuries with sacral fractures. A vertical sacral fracture was artificially induced by vertical loading in eight pelvises from cadavers, which were then fixed with two 6.5 mm iliosacral lag screws or two 6.4 mm transiliac bars. The pelvises were then loaded again to failure. The mean strength of iliosacral lag screw fixation was 819 newtons and for transiliac bars it was 1066 newtons, but the study was too small for the difference to be judged as statistically significant. Various advantages and disadvantages of each method of fixation are discussed.

Bone Plates↗
PubMed1996

Structure-activity relationships for SNC80 and related compounds at cloned human delta and mu opioid receptors.

The racemic compound (+/-)-BW373U86 ¿(+/-)-4-((alpha R*)- alpha-((2S*,5R*)-4-allyl-2,5-dimethyl-1-piperazinyl)-3-hydroxy- benzyl)-N,N-diethylbenzamide dihydrochloride} is a potent delta opioid receptor agonist in the mouse vas deferens assay with little mu or kappa opioid receptor activity in the guinea pig ileum tissue preparation. In contrast, radioligand binding studies show that (+/-)-BW373U86 is only about 10-fold selective for delta over mu opioid receptors. Studies of the enantiomeric forms of (+/-)-BW373U86 and derivatives (SNC80 and related compounds) show that some of these isomers are significantly better in both receptor binding and pharmacological selectivity than (+/-)-BW373U86. In this study we have determined the binding affinities of 10 different SNC80-related compounds at cloned human delta and mu opioid receptors and measured the potency of SNC80 for the inhibition of forskolin-stimulated adenylyl cyclase. The most selective delta receptor ligand (SNC162) differed from SNC80 by the absence of the 3-methoxy substitution of the benzyl ring. The Ki for SNC162 at the delta receptor (0.625 nM) was over 8700-fold lower than that at the mu receptor (5500 nM), making this the most selective delta receptor ligand available. Reduction of the allyl side chain of SNC80 to produce radiolabeled [3H]SNC121 allowed direct measurement of the association and dissociation rate constants. SNC80 was 26-fold less potent than [D-Pen2, pCI-Phe4, D-Pen5]enkephalin in the delta receptor adenylyl cyclase inhibition assay, but showed full agonist activity with an EC50 value of 9.2 nM. The regulation of SNC80 binding affinity to the delta receptor by GTP analogs is undetectable in [3H]naltrindole binding inhibition studies, but direct binding studies with [3H]SNC121 in the presence of 100 microM 5'-guanylylimidotriphosphate show a 55% reduction in maximum binding site density consistent with a lower affinity for a part of the receptor population. Addition of 120 mM sodium chloride reduces SNC80 affinity nearly 40-fold in [3H]naltrindole binding inhibition studies. The results of these studies define specific structural features of these compounds responsible for opioid receptor interactions and suggest a possibly novel mechanism for delta receptor activation.

Animals↗
PubMed1996

A possible association of HLA-DR beta 1*04 subtypes and rheumatoid arthritis of peptide binding region amino acids.

HLA-DR beta 1*04 subtypes associated with rheumatoid arthritis (RA) were studied by polymerase chain reaction with sequence specific primers and the 86th amino acid of the DR beta 1 chain was analysed in RA patients vs healthy controls. The frequency of HLA-DR beta 1*0401 and 0404/0407 alleles was significantly increased in RA patients vs the controls, HLA-DR beta 1*0401 and 0404 being the dominant variants in RA. In most RA patients hydrophilic glycine proved to be the 86th amino acid of the peptide binding region thus it could have an effect on the development of RA.

Alleles↗
PubMed1996

Molecular genetic analysis of HLA-DRB, -DQA, and -DQB polymorphisms in Hungarians and distribution of the DRB1*03 allele in adults and newborns.

We describe here the genetic variability of HLA-DRB1, -DQA, and -DQB in 140 healthy individuals from Hungary, including 95 randomly selected adults and 45 newborns. Allele and haplotype frequencies as well as linkage disequilibria were calculated. It was found that HLA-DRB1*11, -DQA1*0501, and -DQB1*0301 predominate in Hungarians. This information may be helpful in the future for HLA and disease association studies. Simultaneously, we observed that the frequency of the DRB1*03 allele differs between adults and newborns. Since it is well known that bearers of HLA-DR3 (and/or B8) antigens may display significant changes in immune parameters, the lower frequency in adults indicates that children with the DR3 antigen are predisposed to immune diseases in adulthood.

Adolescent↗
PubMed1996

On the cardioprotective effect of adenosine.

In isovolumically perfused Langendorff heart preparations of guinea pigs adenosine-depending on the experimental protocol-more or less could prevent the hypoxia-induced decrease in myocardial adenosine triphosphate [ATP], creatine phosphate [CP], glycogen and increase in lactate, i.e. showed cardioprotection.

Adenosine↗
PubMed1995

Properties of TAN-67, a nonpeptidic delta-opioid receptor agonist, at cloned human delta- and mu-opioid receptors.

2-methyl-4a alpha-(3-hydroxyphenyl)-1,2,3,4,4a,5,12,12a alpha-octahydro-quinolino[2,3,30g]isoquinoline (TAN-67) is a nonpeptidic delta-opioid receptor agonist. This report describes its receptor binding affinity and agonist potency at human and mouse delta and mu-opioid receptors. The binding affinities of TAN-67 and the cyclic enkephalin analog, (D-Pen2, 4'-Cl-Phe4, D-Pen5]enkephalin (pCl-DPDPE) were measured by radioligand binding inhibition studies at mouse and human variants of the delta and mu-opioid receptor using [3H]Naltrindole and [3H]D-Phe-Cys-Tyr-D-Trp-Orn-Thr -Pen-Thr-NH2, respectively. TAN-67 showed high binding affinity (Ki = 0.647 nM) at the human delta-opioid receptor and high delta-opioid receptor binding selectivity ( > 1000-fold) relative to the human mu-opioid receptor. TAN-67 also showed high potency (EC50 = 1.72 nM) for the inhibition of forskolin-stimulated cAMP accumulation at human delta-opioid receptors expressed by intact Chinese hamster ovary cells but low potency (EC50 = 1520 nM) at human mu-opioid receptors expressed by intact B82 mouse fibroblast cells. The results show that TAN-67 has similar binding affinities, selectivity and potencies as pCl-DPDPE at human delta and mu-opioid receptors. These results combined with the nonpeptidic structure of TAN-67 suggest that this compound has therapeutic potential as a delta-opioid receptor agonist.

Analgesics↗
PubMed1995

[Experiences at the regional stroke centrum of the Erzsébet Hospital].

The authors describe the organizational structure, starting-up procedure and the experiences gained during the first half year run of a regional stroke center deserving 3 districts of Budapest. The neurological ward of the Erzsébet hospital has became active from 1. january 1993, as a first step in the implementation of the capital stroke project. They report the history, circumstances of hospitalisation, type and course of disease of 160 cerebrovascular patients and the diagnosis leading to death of 31 patients.

Adult↗
PubMed1995

The role of the Val353 residue in antagonist binding to rat CCK-B receptors.

The Val353 residue of the rat cholecystokinin-B (CCK-B) receptor was mutated to Leu to test whether this residue is part of a binding site for antagonists having different chemical structures. The agonist radioligand [3H]SNF 8702 showed similar affinity for both wild-type and mutant receptors. Mutation of the CCK-B receptor reversed the order of affinities for the asperlicin derivatives from L-365,260 > devazepide (wild-type) to devazepide > L-365,260 (mutant) but had no effect on the affinity of the peptoid CCK-B receptor antagonist Cam-1028. The results show that Val353 is not part of a general CCK-B receptor antagonist recognition site and that Cam-1028 is recognized at a receptor site distinct from that binding asperlicin derivatives.

Amino Acids↗
PubMed1995

Effects of method of internal fixation of symphyseal disruptions on stability of the pelvic ring.

This study tested different methods of internal fixation of a symphyseal disruption, in comparison with the mechanics of the intact pelvis. Unembalmed cadaveric pelves were tested in simulated bilateral stance in a servohydraulic materials-testing machine. Motion of the superior and inferior pubic symphysis, and at two levels of the posterior sacroiliac complex, was measured using high resolution displacement transducers. The fixations tested were (1) double plating (4.5 mm reconstruction plates), (2) wire loops around two 6.5 mm, fully threaded cancellous screws, and (3) an absorbable suture material (polydioxanone). Each pelvis was first tested intact, recording displacements in response to a cyclic axial load up to a maximum of 500 N applied through the proximal sacrum. The pubic symphysis was then sectioned and the sacrum fractured to produce an unstable pelvis (Tile C-type). Recordings were then repeated, following fixation of the sacral fracture with lag screws and sequential fixation of the symphysis with each of the test methods. The results from eight pelves revealed that internally fixed symphyseal motion was generally greater than intact, regardless of fixation method. The superior symphysis was usually compressed, while there was distraction inferiorly. Wiring resulted in significantly less symphyseal motion than the other methods (P < 0.02), provided four loops were used, reducing the separation inferiorly. There was no significant difference in sacral fracture motion between the three methods. The results indicate that in osteoporotic bone, as used in this study, symphyseal wiring is best able to oppose the tensile loads in the inferior symphysis that are associated with bilateral stance loading. These biomechanical findings must be interpreted within the broader context of surgical management of these complex injuries.

Aged↗
PubMed1995

Oral signs and symptoms in patients with undiagnosed vitamin B12 deficiency.

The oral manifestations of glossitis, stomatitis and mucosal ulceration in vitamin B12 deficiency have long been recognised. These oral changes may occur in the absence of symptomatic anaemia or of macrocytosis. The aim of this paper is to describe a retrospective study of the wide range of oral signs and symptoms reported by 14 patients found to have a previously undiagnosed vitamin B12 deficiency. None of the patients described in this study had generalised symptoms sufficiently advanced to arouse suspicions of vitamin B12 deficiency. The essential criteria for the diagnosis of pernicious anaemia are also discussed.

Anemia↗
PubMed1994

[Can the storage time be limited for cryopreserved pre-embryos?].

The authors discuss about the questions connected with the time of the storage of the human cryopreserved preembryos. After approaching the different interest of the participants and giving the variable international statements the authors are preparing their suggestion for the limitation of the storage of the cryopreserved human preembryos.

Cryopreservation↗
PubMed1994

[Functioning conditions of laboratories dealing with cryopreservation of human pre-embryos].

The authors discuss about the functional conditions of the Human Reproductive Laboratories dealing with the cryopreservation of the human preembryos. They determine the safety specifications and recommend documentation of the cryopreservation based on their own practice. Finally they suggest the licensing-controlling system of the Human Reproductive Laboratories concerning cryopreservation of the human preembryos.

Cryopreservation↗
PubMed1994

[Programmed pre-embryonic freezing in the pronuclear stage].

The authors discuss about freezing procedure of surplus pronuclear stage praeembryos in six cases. The total amount of praeembryos were 36. From these nine were thawing and were cultured further. The surviving rate was 88.8%, the development to blastocysts rate was 77.7%. The freezing procedure in pronuclear stage needs some extra methodological force. The success, increasing influence on pregnancy rate and the benefit that reduces the IVF-ET patient's intolerance procedure is also an important factor. Beneath the cost saving effect of this intervention, the cryopreservation technique for the institutes performing this way of assisted reproduction is highly suggested.

Cryopreservation↗
PubMed1994

[Cardioprotective effect of levcromakalim in isolated guinea pig heart preparations].

The aim of present work was to study the cardioprotective effect of the potassium channel opener levcromakalim at a low concentration (0.3 microM) which does not depress heart rate and left ventricular developed pressure. For the determination of the protection against 10 or 20 min duration of hypoxia (95% N2 + 5% CO2) in isovolumically-perfused Langendorff heart preparations of guinea-pigs biochemical parameters (ATP, phosphocreatine, lactate and glycogen) were used. Under normoxic (95% O2 + 5% CO2) conditions 0.3 microM levcromakalim has not changed myocardial high energy phosphates, glycogen, lactate and the hypoxia induced decrease in ATP and phosphocreatine. The 10 min hypoxia induced increase in lactate and decrease in glycogen have--slightly but not significantly--been moderated and when the duration of hypoxic perfusion has lasted 20 min, this protection became significant. It is supposed that the preservation of glycogen stores induced by levcromakalim may contribute to the decrease of intracellular acidosis evoked by hypoxia. Therefore--in such experimental condition-, this mechanism may constitute the biochemical basis of cardioprotective effect of levcromokalim.

Adenosine Triphosphate↗
PubMed1992

[Idiopathic thrombocytopenia caused by varicella].

The authors deal with the case of a 6-year old girl in whom thrombocytopenia developed with haemorrhagic symptoms as a rare complication of varicella. They give a short review about the reasons and the etiology of idiopathic thrombocytopenic purpura, and deal with the mechanism of thrombocytopenia caused by varicella.

Chickenpox↗