PubMed Health⌕ Search

Biomedical subjects

G Gyapay

Publications and source records attributed to G Gyapay.

52 records · Page 3Linked to original sources
PubMed1994

The 1993-94 Généthon human genetic linkage map.

In 1992, we described a second-generation genetic linkage map of the human genome. Using 1,267 new microsatellite markers, we now present a new genetic linkage map containing a total of 2,066 (AC)n short tandem repeats, 60% of which show a heterozygosity of over 0.7. Statistical linkage analysis based on the genotyping of eight large CEPH families placed these markers in the 23 linkage groups. The map includes 1,266 intervals and spans a total distance of 3690 centiMorgans (cM). A total of 1,041 markers could be ordered with odds ratios greater than 1000:1. About 56% of this map is at a distance of 1 cM or less from one of its markers.

Animals↗
PubMed1994

Congenital nephrotic syndrome of the Finnish type maps to the long arm of chromosome 19.

Congenital nephrotic syndrome of the Finnish type (CNF) is an autosomal recessive disease that is characterized by massive proteinuria and nephrotic syndrome at birth. CNF represents a unique, apparently specific dysfunction of the renal basement membranes, and the estimated incidence of CNF in the isolated population of Finland is 1 in 8,000 newborns. The basic defect is unknown, and no specific biochemical defect or chromosomal aberrations have been described. Here we report the assignment of the CNF locus to 19q12-q13.1 on the basis of linkage analyses in 17 Finnish families. Multipoint analyses and observed recombination events place the CNF locus between multiallelic markers D19S416 and D19S224, and the significant linkage disequilibrium observed suggests that the CNF gene lies in the immediate vicinity of the markers D19S224 and D19S220.

Cell Line↗
PubMed1993

Localization of Friedreich ataxia phenotype with selective vitamin E deficiency to chromosome 8q by homozygosity mapping.

Friedreich ataxia and ataxia with selective vitamin E deficiency (AVED) share very similar clinical phenotypes. We have mapped the AVED locus to proximal 8q with only three large consanguinous Tunisian families, representing to our knowledge the first use of homozygosity mapping for primary linkage analysis. Subsequently, three additional families showed linkage with the same markers. A maximum lod score of 17.9 was obtained at theta = 0 for the haplotype D8S260-D8S510, consisting of the two closest markers. With only 6 families, the AVED locus is therefore mapped precisely as illustrated by the lod-1 confidence interval of 2.4 cM on either side of D8S260-D8S510. Isolation of a yeast artificial chromosome contig > 800 kilobases (kb) showed that D8S260 and D8S510 are less than 400 kb apart.

Adult↗
PubMed1992

A second-generation linkage map of the human genome.

A linkage map of the human genome has been constructed based on the segregation analysis of 814 newly characterized polymorphic loci containing short tracts of (C-A)n repeats in a panel of DNAs from eight large families. Statistical linkage analysis placed 813 of the markers into 23 linkage groups corresponding to the 22 autosomes and the X chromosome; 605 show a heterozygosity above 0.7 and 553 could be ordered with odds ratios above 1,000:1. The distance spanned corresponds to approximately 90% of the estimated length of the human genome.

Chromosome Mapping↗
PubMed1991

Effect of conditioned media of acute myeloid leukemia blast cells on complement synthesis by cultured human cells of monocyte and hepatocyte origin.

The effect of conditioned media of 3-day cultures of blast cells from peripheral blood of 5 patients with acute myeloid leukemia (CM-AML) was studied on the synthesis of C2, factor B (Bf) and C1 esterase inhibitor (C1-INH) by human monocyte-macrophage cultures and HepG2 hepatoma cell line. The level of C2 in the culture supernatants was measured by immune hemolysis, those of Bf and C1-INH by ELISA. CM-AML was added to the monocyte cultures on day 3 and replaced by culture fluid on day 6. Compared to the control cultures, CM-AML significantly increased C2 and Bf levels and slightly decreased C1-INH levels in the culture fluids on day 6. On day 9, Bf synthesis enhancement still could be observed but C2 and C1-INH levels did not significantly differ from those of the control. CM-AML significantly increased the synthesis of factor B by the HepG2 cells too. A strong correlation was found between the results of the Bf protein and RNA determinations, which means that the supernatants of AML blasts affect the gene expression of factor B at a pretranslational level. The selective complement synthesis modifying effect of CM-AML was not due to interferons (IFN) because neither IFN-alpha nor IFN-gamma could be detected in these conditioned media. The present findings indicate that the hypercomplementemia observed in AML patients can be due to unknown factor(s) produced by leukemic blast cells.

Blood Cells↗
PubMed1991

Human recombinant macrophage colony-stimulating factor (M-CSF) increases Cl-esterase inhibitor (Cl-INH) synthesis by human monocytes.

The ability of macrophage colony-stimulating factor (M-CSF) to influence production of complement proteins by cultured human monocytes was studied. Three-day-old cultures of human monocytes were treated with 250-1000 U/ml recombinant human M-CSF (Cetus Corporation, Emeryville, CA). After 3 days the M-CSF containing medium was replaced by the same medium without M-CSF, and the cells were cultured for 3 more days. Samples taken at the removal of M-CSF and 3 days later were tested for the concentration of factor B and Cl-esterase inhibitor (Cl-INH) using ELISA methods, and C2 by using an immunohaemolytic assay. M-CSF induced a marked dose-dependent increase in the synthesis of Cl-INH, but did not significantly change Bf and C2 production. The findings suggest that M-CSF is able to influence selectively the complement protein-producing ability of cultured human monocytes.

Cells, Cultured↗
PubMed1985

Drug action and chromatin structure. I. Adriamycin binding to core particle of nucleosomes and subsequent enhanced DNA fragmentation induced by micrococcal nuclease.

The relevance of the subunit structure of chromatin to the mode of action of Adriamycin in Novikoff hepatoma had been investigated. To elucidate whether drug binding takes place at random along the chromatin fiber or not Novikoff hepatoma nuclei treated with Adriamycin in vivo were digested with Micrococcal nuclease and were subsequently separated into three fractions, S1, S2 and P2. In these chromatin fraction Adriamycin and the DNA content was determined. DNA were isolated from the above fractions and were analyzed by polyacrylamide gel electrophoresis, furthermore the S2 fraction was sedimented on sucrose density gradient. The results indicate that binding of Adriamycin takes place preferentially on the core particle inducing structural alterations. Adriamycin binding not only enhanced DNA nuclease digestion but altered the size of the fragments.

Animals↗
PubMed1984

Further studies on the biochemical characterization of the MC-29 virus derived transplantable hepatoma (VTH). II. Modification of cyclic adenosine-3',5'-monophosphate levels by catecholamines, glucagon and Vinca alkaloids in normal chicken liver and VTH.

Basic and stimulated intracellular cAMP concentrations were measured in normal chicken liver and MC-29-virus-derived transplantable hepatoma (VTH) slices after in vitro incubation. Data indicated the preservation of catecholamine receptor but a loss of glucagon receptor in VTH. Comparing the relative stimulatory action of various catecholamines on cAMP concentration it was concluded that as in normal liver a predominantly beta 2-adrenergic receptor exists in the VTH, but its response to adrenaline is greater. Vinca alkaloids induced higher cAMP concentration in VTH than in normal liver. This stimulation was abolished by glucagon, while catecholamines and Vincristine acted in a synergistic manner on cAMP concentration.

Animals↗
PubMed1979

Acridine orange staining of the mammalian fibroblast cell coat.

Acridine orange selectively binds to glycos- and galactosaminoglycan (GAG) compounds in the presence of Na+ in low concentrations. We have worked out a cytochemical method, which is suitable for the specific demonstration of surface GAG components. The method consists of a glutaraldehyde prefixation, an acridine orange block-staining for 48 h and an OsO4 postfixation for some hours. The specificity of the staining was verified with the help of fluorimetric--in vitro--measurements and enzymatic digestions, respectively.

Acridine Orange↗
PubMed1979

Spontaneous and chemically-induced transformation of mouse fibroblasts in culture. Biochemical aspects of the transformed cells.

Fibroblast cultures were established from the lung tissue of CBA T6T6 mouse embryos. Lines characterized by infinite growth transformation (MFL) were used as untreated controls till the 21st and 29th passages, respectively. After that period, an unrestrained growth transformation developed spontaneously. The cell line was then designated as STMFL. At the 8th passage of an MFL, 20-methylcholanthrene (MC) treatment was performed. The treatment resulted in a cell line (MCMFL) characterized also by unrestrained growth transformation. The nuclear protein pattern obtained by two-dimensional gel electrophoresis showed differences between STFL and MCMFL. The activity of two microsomal enzymes - aryl hydrocarbon hydroxylase and ethylmorphin demethylase - measured in the exponential growth stage of the cultures showed a decrease in the case of STMFL, compared to the MFL, and practically disappeared in the case of MCMFL.

Animals↗
PubMed1976

Binding of alkylamines to trypsin as measured by difference spectroscopy.

The effect of n-propylamine, n-butylamine and n-pentylamine on trypsin at pH 5.4, at 25 degrees and 7 degrees C was investigated by the difference spectroscopic technique. The difference spectra were found to be similar for all three alkylamines tested. The difference between the absorbance minimum near 290 nm and the absorbance maximum near 297 nm taken as the measure of perturbation, the following values were obtained for the dissociation constant of the enzyme-ligand complex as calculated from the dependence of this perturbation upon alkylamine concentration at 25 degrees: propylamine, 6.0 X 10(-3) M; butylamine, 3.0 X 10(-3) M; pentylamine, 4.3 X 10(-4) M; and at 7 degrees: butylamine: 5.6 X 10(-3) M the chromophores situated in the active centre. It seems probable that the binding of an alkylamine gives rise to a conformational change which results in the rotation of Tyr-228 and Trp-215 residues towards the hydrophobic surroundings. This dislocation is a part of the minute change that leads to the activation of the catalytic site.

Amines↗
PubMedDate not supplied

Chromatin alterations and gene function disorder in MC-29 virus-derived hepatoma.

The disorder of gene expression in hepatomas was studied by following certain metabolic alterations (enzyme stimulation, nucleic acid labeling) after glucocorticoid treatment and analyzing the site of action of glucocorticoids. Compared to normal liver, the MC-29 virus-derived transplantable hepatoma (VTH) responded abnormally to glucocorticoids, which failed to stimulate the activity of certain enzymes (glucose-6-phosphatase, aryl hydrocarbon hydroxylase) or to inhibit DNA synthesis. Since the binding capacity of the cytosol steroid receptor was the same in liver and VTH but the interaction between the steroid receptor and DNA was reduced in VTH, it was concluded that structural alterations of chromatin nonhistones--including processed steroid receptor--may be responsible for the lack of physiological responses to steroids in VTH. Furthermore, the increased proportion or repetitive sequences in VTH DNA may be a feature of the disorder of gene regulation in malignant cells.

Animals↗
PubMedDate not supplied

Effect of interferon-alpha (IFN alpha) on various human tumor xenografts.

The growth of some human tumor xenografts (3 out of 8, melanoma, non-Hodgkin's lymphoma, squamous cell carcinoma) was successfully--but moderately and temporarily--inhibited, when interferon-alpha (EGIS, Hungary) was given for 10 days. The route of administration (intratumoral or intraperitoneal) was usually not a decisive factor. An attempt to potentiate IFNa action with Zymozan or Cyclophosphamide did not succeed.

Animals↗
PubMedDate not supplied

Chromosomal localization of the adrenoleukodystrophy-related gene in man and mice.

We report here on the chromosomal mapping of the adrenoleukodystrophy-related (ALDR) gene on both the human and the mouse genomes. This gene encodes a peroxisomal ATP binding cassette transporter, closely related to the transporter identified as responsible for the adrenoleukodystrophy phenotype. ALDR maps on the syntenic region on murine and human autosomes. In addition, we could determine its position in relation to known microsatellite framework markers; this will allow to test its role in Zellweger syndrome and/ or related peroxisomal disorders.

ATP Binding Cassette Transporter, Subfamily D↗