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Biomedical subjects

A Nagy

Publications and source records attributed to A Nagy.

At least 109 records · Page 6Linked to original sources
PubMed2000

FACS for the isolation of individual cells from transgenic mice harboring a fluorescent protein reporter.

Flow cytometry is extensively used for the isolation of discreet populations of cells from complex pools. The advent of autofluorescent (AFP) reporters such as wild type Green Fluorescent Protein (wtGFP) (Chalfie et al., 1994) and its variants, including enhanced green fluorescent protein (EGFP) and enhanced yellow fluorescent protein (EYFP) (Cormack et al., 1996), as vital reporters opens up the possibility of sorting live reporter-expressing cells. Moreover the use of these reporters in transgenics (Okabe et al., 1997) or mice carrying homologously targeted loci (Godwin et al., 1998) should enable the direct isolation of reporter-expressing cells from any desired lineage. Here we have assessed this approach in transgenic mice. ES cell-mediated transgenesis was used for generating a line of mice that express an autofluorescent EYFP reporter in the heart and part of the neural tube at midgestation. Pools of fluorescent cells harboring and expressing the EYFP reporter were isolated from defined regions of embryos and their origin confirmed by assaying the expression of domain-defined marker genes. Such a tool should prove useful for gaining access to any given lineage that can be fluorescent protein reporter tagged.

Animals↗
PubMed2000

The mouse Pdgfc gene: dynamic expression in embryonic tissues during organogenesis.

The signaling activity of Platelet-derived growth factors A and B (PDGF-A and PDGF-B) that is mediated through the two receptor kinases, PDGFR-alpha and PDGFR-beta has been shown to be critical for the development of the cardiovascular organs, the kidney, the lung and the central nervous system. During the cloning of genes for VEGF related proteins, we isolated a mouse cDNA that can encode for a protein of 345 amino acids. A comparison of the amino acid sequence reveals that this predicted gene product displays 95% identity to human PDGF-C. The mouse Pdgfc gene maps to a region of chromosome 17 that is syntenic to human chromosome 6p21.3 In E9. 5-E15.5 mouse embryo, Pdgfc is widely expressed in the surface ectoderm and later in the germinal layer of the skin, the olfactory and otic placode and their derivatives and the lining of the oral cavity. In the gut and visceral organs, such as the lung and the kidney, Pdgfc mRNA is first expressed in the endodermal epithelium and later in mesenchymal tissues associated with the endodermal structures. Similar to other PDGFs, Pdgfc is widely expressed in mesenchymal precursors and the myoblast of the smooth and skeletal muscles. Contrary to PDGF-A, Pdgfc is not expressed in the central nervous system, except in the cerebellum, and neurogenic derivatives of the neural crest cells. Pdgfc is also absent from the heart and the vascular endothelium

Amino Acid Sequence↗
PubMed2000

Electrophoretic karyotypes of some related Mucor species.

Contour clamped homogeneous electric field (CHEF) gel electrophoresis was used to obtain electrophoretic karyotypes from nine Mucor strains representing five different species (M. bainieri, M. circinelloides, M. mucedo, M. plumbeus and M. racemosus). The chromosomal banding patterns revealed high variability among the isolates. The sizes of the DNA in the Mucor chromosomes were estimated to be between 2.5 and 8.7 Mb. The total genome sizes were calculated to be between 30.0 and 44.7 Mb. The applicability of these electrophoretic karyotypes for the investigation of genome structure, for strain identification and for species delimitation is considered.

Chromosomes, Fungal↗
PubMed2000

Administration of a targeted cytotoxic analog of luteinizing hormone-releasing hormone inhibits growth of estrogen-independent MDA-MB-231 human breast cancers in nude mice.

Receptor targeted chemotherapy is less toxic and more effective than conventional chemotherapy. Receptors for luteinizing hormone-releasing hormone (LH-RH) are found in about 50% of human breast cancers. Highly potent cytotoxic radical 2-pyrrolinodoxorubicin (AN-201) was linked to the agonistic analog [D-Lys6]LH-RH to form cytotoxic LH-RH analog AN-207. We evaluated whether AN-207 could be targeted to the hormone-independent MDA-MB-231 human breast cancers. Nude mice bearing MDA-MB-231 tumors were injected i.v. with 250 nmol/kg doses of cytotoxic radical AN-201, cytotoxic LH-RH analog AN-207, the unconjugated mixture of AN-201 and carrier [D-Lys6]LH-RH, [D-Lys6]LH-RH alone and vehicle (control). The growth of MDA-MB-231 tumors in animals given a single dose of AN-207 was inhibited significantly (p = 0.01) for 3 weeks after injection, whereas tumors in all the other groups grew steadily. All cytotoxic compounds produced leukopenia, but the strongest lymphocyte suppression was caused by cytotoxic radical AN-201. Three weeks after treatment, the presence of mRNA for LH-RH receptors was demonstrated by RT-PCR in all the groups and radioreceptor assays demonstrated high-affinity binding sites for LH-RH on tumor cell membranes of control animals and those treated with AN-201, the carrier peptide alone or in combination with AN-201. At this time point binding assays did not reveal the expression of membrane proteins in tumors treated with AN-207, but 60 days after administration of AN-207, high affinity LH-RH binding sites were found again in MDA-MB-231 tumors. These results indicate that cytotoxic LH-RH analog AN-207 could be utilized for receptor targeted chemotherapy of breast cancers expressing receptors for LH-RH.

Animals↗
PubMed2000

Identification of mutations in 15 Hungarian families with hereditary protein C deficiency.

Hereditary protein C deficiency represents about 2-9% of inherited thrombophilias. Our aim was to elucidate the molecular basis of protein C deficiency in 25 members of 15 Hungarian families with venous thromboembolic diseases and to identify hitherto undescribed genetical defects in the protein C (PROC) gene. The exons of the PROC gene were screened for mutations with the combination of polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE), and/or PCR and single-strand conformation polymorphism (SSCP) analysis. The amplified DNA fragments with aberrant migration during DGGE and SSCP were sequenced. Mutations were determined in the PROC gene in all of the examined families: one nonsense mutation, one rare frameshift deletion and nine different missense mutations, of which three were novel (1493 A-->G, 35Asp-->Gly; 6231 G-->A, 173Gly-->Glu; 8476 C-->T, 254Thr-->Ile). The combination of hereditary protein C deficiency with other hereditary thrombophilias was rather common. DGGE and SSCP were proved to be efficient and cost-effective screening methods in the genetic analysis of hereditary protein C deficiency.

Adult↗
PubMed2000

Causes of death of patients with multiple injuries in Debrecen, Hungary.

OBJECTIVE: To find out the main causes of death of people who had multiple severe injuries. DESIGN: Retrospective study. SETTING: Teaching hospital, Hungary. SUBJECTS: 86 people with severe multiple injuries, of whom 59 died and had necropsies. MAIN OUTCOME MEASURE: Establishment of a database. RESULTS: Consumption of alcohol was a common precursor. Head and chest injuries predominated. More pedestrians than people in vehicles were killed, and there were 8 suicides and 3 murders. There were no gunshot injuries. CONCLUSIONS: Reduction of deaths from multiple injuries is as much a socioeconomic as a medical matter.

Alcohol Drinking↗
PubMed2000

The Ketel gene encodes a Drosophila homologue of importin-beta.

The Drosophila melanogaster Ketel gene was identified via the Ketel(D) dominant female sterile mutations and their ketel(r) revertant alleles that are recessive zygotic lethals. The maternally acting Ketel(D) mutations inhibit cleavage nuclei formation. We cloned the Ketel gene on the basis of a common breakpoint in 38E1. 2-3 in four ketel(r) alleles. The Ketel(+) transgenes rescue ketel(r)-associated zygotic lethality and slightly reduce Ketel(D)-associated dominant female sterility. Ketel is a single copy gene. It is transcribed to a single 3.6-kb mRNA, predicted to encode the 97-kD Ketel protein. The 884-amino-acid sequence of Ketel is 60% identical and 78% similar to that of human importin-beta, the nuclear import receptor for proteins with a classical NLS. Indeed, Ketel supports import of appropriately designed substrates into nuclei of digitonin-permeabilized HeLa cells. As shown by a polyclonal anti-Ketel antibody, nurse cells synthesize and transfer Ketel protein into the oocyte cytoplasm from stage 11 of oogenesis. In cleavage embryos the Ketel protein is cytoplasmic. The Ketel gene appears to be ubiquitously expressed in embryonic cells. Western blot analysis revealed that the Ketel gene is not expressed in several larval cell types of late third instar larvae.

Amino Acid Sequence↗
PubMed2000

Measurement of left ventricular volumes and ejection fraction after intravenous contrast agent administration using standard echocardiographic equipment.

The enhancement of endocardial border delineation using second harmonic imaging and contrast administration improves the measurement of ventricular volumes. In the majority of existing echocardiographic equipment, however, harmonic imaging is not yet available. The aim of this study was to assess the feasibility of the measurement of left ventricular volumes and ejection fraction after intravenous administration of the contrast agent Levovist using standard echocardiographic equipment and fundamental imaging modality. In 10 patients with good-quality two-dimensional echo imaging, 4 g (400 mg/mL concentration) of Levovist was injected intravenously. Hewlett-Packard Sonos 2000 ultrasound equipment without second harmonic imaging capability was used. To avoid the destruction of microbubbles, the echo machine was set to produce only one end-systolic and one end-diastolic frame in each cardiac cycle (dual triggering). Native and contrast imaging measurements of left ventricular volumes and ejection fractions calculated by modified Simpson's rule were compared in the fundamental mode. Intraobserver and interobserver variability values were assessed. End-diastolic volumes in native continuous and triggered mode and by contrast echo were 126 +/- 48, 121 +/- 46, and 130 +/- 50 mL, respectively (NS), whereas end-systolic volumes were 79 +/- 48, 76 +/- 45, and 79 +/- 46 mL, respectively (NS). Calculated ejection fraction using the three different imaging modalities were 0.41 +/- 0.16, 0.41 +/- 0.16, and 0.42 +/- 0.16 (NS). The intraobserver and interobserver reproducibility values were excellent in triggered mode. Standard echocardiographic equipment with fundamental imaging modality in the triggered mode is suitable for the measurement of left ventricular volumes after intravenous Levovist administration. In clinically difficult patients, contrast echocardiography in triggered mode may be applied even if echocardiographic equipment does not have harmonic imaging possibility.

Cardiomyopathy, Dilated↗
PubMed2000

Mice null for sox18 are viable and display a mild coat defect.

We have previously shown that Sox18 is expressed in developing vascular endothelium and hair follicles during mouse embryogenesis and that point mutations in Sox18 are the underlying cause of cardiovascular and hair follicle defects in ragged (Ra) mice. Here we describe the analysis of Sox18(-/-) mice produced by gene targeting. Despite the profound defects seen in Ra mice, Sox18(-/-) mice have no obvious cardiovascular defects and only a mild coat defect with a reduced proportion of zigzag hairs. A reduction in the amount of pheomelanin pigmentation in hair shafts was also observed; later-forming hair follicles showed a reduced subapical pheomelanin band, giving Sox18(-/-) mice a slightly darker appearance than Sox18(+/+) and Sox18(+/-) siblings. Sox18(-/-) mice are viable and fertile and show no difference in the ability to thrive relative to littermates. Because of the mild effect of the mutation on the phenotype of Sox18(-/-) mice, we conclude that the semidominant nature of the Ra mutations is due to a trans-dominant negative effect mediated by the mutant SOX18 proteins rather than haploinsufficiency as has been observed for other SOX genes. Due to the similarity of SOX18 to other subgroup F SOX proteins, SOX7 and -17, and the overlap in expression of these genes, functional redundancy amongst these SOX proteins could also account for the mild phenotype of Sox18(-/-) mice.

Alleles↗
PubMed2000

Human ovarian cancers express somatostatin receptors.

Characteristics of receptors for somatostatin (SST) analog RC-160 on 17 surgical specimens of human epithelial ovarian cancer and two human ovarian cancer lines were determined by ligand competition assays. The expression of mRNA for four SST receptor subtypes (sst1, sst2A, sst3 and sst5) was investigated by RT-PCR. Thirteen of 17 specimens (76%) exhibited high affinity binding sites for RC-160 with Kd = 6.55 nmol/L and a Bmax = 575.4 fmol/mg membrane protein. Specific receptors for RC-160 were also found in xenografts of OV-1063 and UCI-107 human ovarian cancer lines. The mRNA for sst1 was detected in 65% of the ovarian cancer specimens, while the incidence of sst2A, sst3 and sst5 was 65%, 41% and 24%, respectively. Both ovarian cancer cell lines also expressed mRNA for these four subtypes. The presence of these SST receptor subtypes in human ovarian cancers allows the use of SST analogs and their radionuclide and cytotoxic derivatives for the diagnosis and treatment of this malignancy.

Adult↗
PubMed2000

Embryonic development is disrupted by modest increases in vascular endothelial growth factor gene expression.

Previous work has shown that heterozygocity for a null mutation of the VEGF-A gene, resulting in a 50% reduction in VEGF-A expression, is embryonic lethal at embroyonic day (E) 9.5 in mice. We now show that two- to threefold overexpression of VEGF-A from its endogenous locus results in severe abnormalities in heart development and embryonic lethality at E12.5-E14. The mutant embryos displayed an attenuated compact layer of myocardium, overproduction of trabeculae, defective ventricular septation and abnormalities in remodeling of the outflow track of the heart. In addition, aberrant coronary development was characterized by formation of oversized epicardial vessels, apparently through vasculogenesis. We infer that embryonic survival requires a narrow window of VEGF-A expression.

3' Untranslated Regions↗
PubMed2000

Candida endocarditis in a premature infant.

Endocarditis is an uncommon complication of invasive candidiasis. We present a fatal case of endocarditis caused by Candida albicans in a very low birth weight infant. The 780-g male infant did not have any structural heart disease and a central venous catheter was not placed. Endocarditis developed in spite of parenteral fluconazole treatment. Echocardiography was a valuable tool in making the diagnosis. The infant died on the 40th day of life. The development of Candida endocarditis in a premature infant who was treated with fluconazole had not been previously reported. In the case of systemic candidiasis, premature infants require very careful monitoring for the progression of the disease, even if antifungal therapy is administered.

Candida albicans↗
PubMed2000

Receptor mediated antiproliferative effects of the cytotoxic LHRH agonist AN-152 in human ovarian and endometrial cancer cell lines.

Eighty percent of human ovarian and endometrial cancers express receptors for luteinizing hormone-releasing hormone (LHRH). These receptors might be used for targeted chemotherapy with cytotoxic LHRH analogs such as AN-152, in which doxorubicin is linked to agonist carrier [D-Lys6]LHRH. The antiproliferative effects of doxorubicin and AN-152 were assessed in LHRH receptor-positive ovarian (EFO-21, EFO-27) and endometrial (HEC-1A, Ishikawa) cancer cell lines as well as in LHRH receptor negative ovarian SKOV-3 and endometrial MFE-296 lines. The mechanism of action of AN-152 was investigated by a blockage of receptors using an excess of the LHRH agonist [D-Trp6]LHRH. In some cases, confocal laser-scanning microscopy was used to visualize the accumulation of AN-152 or doxorubicin within the cells. In 3 of 4 LHRH receptor-positive cell lines (EFO-21, HEC-1A, Ishikawa) AN-152 was more effective than doxorubicin in inhibiting cell proliferation. The effect of AN-152 was shown to be receptor-mediated because it could be reduced by competitive blockade of the LHRH receptors with [D-Trp6]LHRH. In contrast, AN-152 was less active than doxorubicin in LHRH receptor-negative lines. Confocal laser-scanning microscopy showed an intranuclear accumulation of AN-152 and competitive inhibition thereof by [D-Trp6]LHRH in LHRH receptor-positive cell lines, but no intracellular accumulation of AN-152 could be detected in the receptor-negative SKOV-3 line. These results suggest a selective receptor-mediated action of AN-152 in receptor-positive cell lines.

Adenocarcinoma↗