Cusp relations for local strongly decaying properties in electronic systems.
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Journal Article↗
Biomedical subjects
A Nagy
Publications and source records attributed to A Nagy.
Simple method for obtaining chromosomal DNA for orthogonal field alternation gel electrophoresis analysis from Phaffia rhodozyma.
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Basidiomycota↗
Synthesis and biological activities of highly potent antagonists of growth hormone-releasing hormone.
In the search for antagonists of human growth hormone-releasing hormone (hGHRH) with high activity, 22 analogs were synthesized by solid-phase methods, purified, and tested biologically. Within the N-terminal sequence of 28 or 29 amino acids of hGHRH, all the analogs contained D-Arg2, Phe(4-Cl)6 (para-chlorophenylalanine), Abu15 (alpha-aminobutyric acid), and Nle27 and most of them had Agm29 (agmatine) substituents. All the peptides, except one, were acylated at the N terminus with different hydrophobic acids--e.g., isobutyric acid (Ibu) or 1-naphthylacetic acid (Nac) in order to study the effect of N-terminal acylation on the antagonistic activity. In the superfused rat pituitary cell system, all the analogs inhibited more powerfully the GHRH-induced growth hormone (GH) release than the standard GHRH antagonist [Ac-Tyr1,D-Arg2]hGHRH-(1-29)NH2. Antagonists [Ibu0,D-Arg2,Phe(4-Cl)6,Abu15,Nle27]hGHRH-(1-28) Agm (MZ-4-71), [Nac0,D-Arg2,Phe(4-Cl)6,Abu15,Nle27]hGHRH-(1-28) Agm (MZ-4-243), [Nac0,D-Arg2,Phe(4-Cl)6,Abu15,Nle27]hGHRH-(1-29) NH2 (MZ-4-169), [Nac0-His1,D-Arg2,Phe(4-Cl)6,Abu15,Nle27]-hGH RH-(1-29)NH2 (MZ-4-181), and [Nac0,D-Arg2,Phe(4-Cl)6,Abu15,Nle27,Asp28]hGH RH-(1-28)Agm (MZ-4-209) inhibited GH release at 3 x 10(-9) M. Among these peptides, MZ-4-243, MZ-4-169, and MZ-4-181 were also long acting in vitro. Antagonist MZ-4-243 inhibited GH release 100 times more powerfully than the standard antagonist and was the most potent in vitro among GHRH antagonists synthesized. Analogs with high inhibitory effects in vitro were also found to have high affinities to rat pituitary GHRH receptors. In experiments in vivo, antagonists [Ibu0,D-Arg2,Phe(4-Cl)6,Abu15,Nle27]-hGHRH-(1-28 )Agm (MZ-4-71), [Nac0,D-Arg2,Phe(4-Cl)6,Abu15,Nle27]hGHRH-(1-29) NH2 (MZ-4-169), and [Nac0-His1,D-Arg2,Phe(4-Cl)6,Abu15,Nle27]hGHR H-(1-29)NH2 (MZ-4-181) induced a significantly greater inhibition of GH release than the standard antagonist. In view of their high antagonistic activity and prolonged duration of action, some of these antagonists of GHRH may find clinical applications, including treatment of certain endocrine disorders and insulin-like growth factor I-dependent tumors.
Amino Acid Sequence↗
Essential role of Mash-2 in extraembryonic development.
The outer layer of the blastocyst, or trophectoderm, is the first cell lineage to differentiate in the mouse embryo, but little is known about the genetic control of its development. Lineage-specific transcription factors may be important in lineage specification, and the product of the Mash-2 gene fulfils the criteria for such a factor. Mash-2 is a mammalian member of the achaete-scute family which encodes basic-helix-loop-helix transcription factors and is strongly expressed in the extraembryonic trophoblast lineage. Mash-2 transcripts are found in the female germ line and in the embryo throughout preimplantation development, but are highly expressed later only in the ectoplacental cone, the chorion and their derivatives in the placenta. Mash-2 transcripts are not found in primary and secondary giant cells, yolk sac or allantois at any post-implantation stage, and are present only transiently and at low levels in the embryo during gastrulation. To analyse the role of Mash-2 in development, we have used gene targeting to generate mice having no Mash-2 function. We report here that Mash-2-/- embryos die from placental failure at 10 days postcoitum. In mutant placentas, spongiotrophoblast cells and their precursors are absent and chorionic ectoderm is reduced. We have rescued this placental mutant phenotype by constructing chimaeras with tetraploid wild-type embryos which contribute almost exclusively to extraembryonic tissues. Mash-2-/- embryos developed normally and adult Mash-2-/- mice were viable, demonstrating that Mash-2 has no major role in the embryo itself. Mash-2 is the first transcription factor shown to play a critical part in the development of the mammalian trophoblast lineage.
Animals↗
[Long-term results of total colectomy insuring restoration of continence].
The early postoperative and long term results of 4 acute (3 toxic megacolon, 1 life threatening bleeding from colon diverticulitis) and 32 elective (16 colitis ulcerosa, 10 familiar polyposis, 4 diffuse Crohn disease, 2 total colon diverticulosis) total colectomies and continence reconstruction has been discussed. In the acute cases the continence has been restored in two steps with Kock reservoir, or with immediate ileorectostomy. In the elective cases the continence was ensured with 16 ileoanal anostomies and pouch formation (4 "S" and 12 "J" pouch), 12 ileorectostomies and two Kock reservoir, the operation has been finished only in 2 cases, with definitive Brooke type ileostomy. The operative lethality was 4/1 and 32/1, the serious postoperative complication rate 4/2 and 32/5 respectively. The long term results of 11 pouch operations and 13 ileorectostomies are discussed. A whole continence were achieved on 11/9 and 13/12 patients respectively. The nocturnal soiling and daily defecation frequency was 75% and 25% higher and the whole rehabilitation time was twice so long after pouch operation then after ileorectostomies. 11/3 and 13/8 patients could return to his or her original occupation. The importance of operations planed and carried out according to the patients personal interest is emphasized. Some special complications and the results of their treatment are discussed.
Adult↗
Exogenous Mtv-7 superantigen transgene expression in major histocompatibility complex class II I-E- mice reconstituted with embryonic stem cell-derived hematopoietic stem cells.
Direct genetic manipulation of hematopoietic cells is limited by the lack of an established hematopoietic stem cell line. It has been demonstrated that embryonic stem (ES) cell<-->tetraploid embryos are completely ES cell-derived and that fetal liver (FL) cells from these embryos support hematopoiesis in lethally irradiated recipients. In this report, we demonstrate that FL cells from ES cell<-->tetraploid embryos support normal lymphopoiesis and T-cell repertoire development. Moreover, the introduction of the Mtv-7 superantigen transgene coding for minor lymphocyte stimulatory antigen 1 into murine hematopoietic cells via reconstitution with ES cell<-->tetraploid FL cells demonstrates that this method can effectively confer stable genetic changes into the hematopoietic tissues without going through the germ line. Long-term and secondary reconstitution with ES cell<-->tetraploid FL cells expressing the Mtv-7 superantigen transgene clonally deleted minor lymphocyte stimulatory antigen 1-reactive T-cell receptor V beta 6+, -8.1+, and -9+ T cells, but not V beta 7+ T cells, in H-2b (I-E-) mice. This model system will be extremely important for analyzing structure-function relationships of molecules involved in proliferation, differentiation, and selection of hematopoietic cells in vivo and for examining hematopoiesis-specific effects of mutations that are lethal during embryogenesis.
Animals↗
Electrophoretic karyotype of Mucor circinelloides.
Contour-clamped homogeneous electric field (CHEF) gel electrophoresis was used to separate chromosomal size DNA molecules of two Mucor circinelloides strains. Electrophoretic karyotypes revealed the presence of eight distinct bands for the M. circinelloides f. lusitanicus strain, and four, presumably multiple, bands for the M. circinelloides f. gryseo-cyanus strain. The approximate sizes of the resolved chromosomal DNA bands ranged from 2.3 to 8.1 Mb, giving estimated genome sizes of 38.7 and 32.6 Mb, respectively. Hybridisation techniques were used to assign the leuA gene to a chromosome.
Chromosomes, Fungal↗
LH-RH analogue carrying a cytotoxic radical is internalized by rat pituitary cells in vitro.
The binding and internalization of a cytotoxic analogue of luteinizing hormone-releasing hormone (LH-RH), T-98 (agonist [D-Lys6]LH-RH linked to glutaryl-2-(hydroxymethyl)anthraquinone), by rat anterior pituitary cells was investigated. Analogue T-98 was bound to pituitary membrane binding sites for LH-RH with a high affinity (Kd = 1.2 nM) and was 17 times more potent in releasing luteinizing hormone (LH) from superfused rat pituitary cells than LH-RH. The labeling of this cytotoxic LH-RH analogue was carried out both with radioactive (125I) and nonradioactive iodine. Monoiodination of the Tyr5 residue of T-98 did not significantly affect its binding affinity but greatly decreased its LH-releasing activity to about 3% of the original value. Di-iodination in the same position lowered binding affinity twenty-threefold and further diminished LH-releasing potency. [125I]T-98 was found to bind very strongly to polystyrene, which precluded the use of regular tissue culture plasticware in our experiments. In pituitary cells cultured in glass vials, binding and internalization of [125I]T-98 were observed, which were time and temperature dependent, and which could be inhibited by excess unlabeled analogue. No enzymatic degradation of labeled T-98 was detected in the culture medium during the incubation. Our results indicate that T-98 is internalized by pituitary gonadotropes through receptor-mediated endocytosis. Because this new class of compounds was designed as anticancer drugs, our findings also suggest that this cytotoxic LH-RH agonist may also be internalized by LH-RH receptors present in breast, prostate, ovarian, and other tumors.
Animals↗
A novel nuclear protein binds centromeric alpha satellite DNA.
We have previously reported the identification of a naturally occurring junction between alpha satellite and satellite III DNA on human chromosomes 13, 14 and 21. Direct sequence analysis has shown that the 9 bp alphoid-derived direct repeat sequence (GTGAAAAAG) present at the junction is fully conserved on these chromosomes. A novel protein, pJ alpha, present in HeLa nuclear extracts, binds to the conserved junction sequence. Mutation analysis of the binding site suggests that pJ alpha can recognize one of the two 9 bp repeats and provides some insight into nucleotides that are important for binding. Competition studies support the possibility that this protein binds a significant portion of genomic alpha satellite DNA. Preliminary protein purification experiments have shown that pJ alpha has a molecular weight of 10-15 kDa.
Base Sequence↗
Plexiform fibrohistiocytic tumour with novel phenotypic features.
Plexiform fibrohistiocytic tumour is a recently described type of fibrohistiocytic tumour, the differentiation pattern of which is poorly understood. A case representing the predominantly fibrohistiocytic type of the tumour is reported. Immunohistochemical analysis supports the histiocytic origin of this entity. The expression of EBM/11 and tissue transglutaminase both in fibroblast-like and histiocyte-like cells indicate that a single cell line produces the dual morphological features. It is proposed that a non-phagocytic epithelioid pattern of histiocytic differentiation characterizes this tumour.
Adult↗
Patient-oriented rehabilitation planning in a single visit: first-year review of the Quick Program.
Persons who are geographically remote or do not qualify for inpatient rehabilitation have limited access to an effective multidisciplinary rehabilitation team. We present an innovative evaluation tool called the Quick Program. This multidisciplinary outpatient assessment involves a previsit database, therapy and physiatrist evaluations, a team meeting, and a patient-family meeting in a one-half day visit. Patient demographics and details of recommendations for the first 41 referrals are described. An average of 2.27 referrals per patient were made to resources outside of the core team, suggesting that the team achieved transdisciplinary status. The number of medical interventions recommended to accomplish rehabilitation goals (mean 2.16 per patient) suggests that the physiatrist was an active participant, and that physician input is crucial to success. We conclude that comprehensive rehabilitation planning for patients who have limited access to multidisciplinary rehabilitation team can be accomplished in a single visit.
Adult↗
Altered phosphorylation of growth-associated protein B50/GAP-43 in Alzheimer disease with high neurofibrillary tangle density.
The growth-associated phosphoprotein B50/GAP-43, associated with axonal proliferation and regeneration, was isolated from superior temporal gyrus (area 22) of seven control and eight Alzheimer disease (AD) postmortem human brains. Membrane and cytoplasmic proteins were fractionated and B50/GAP-43 was isolated by reverse-phase HPLC and gel electrophoresis. B50/GAP-43 was identified with rabbit polyclonal antibodies 4P3 (generated against the calmodulin binding domain of B50/GAP-43) and 1B5 (generated against whole bovine B50/GAP-43). B50/GAP-43 protein was further separated into phosphorylated and dephosphorylated species by calmodulin-Sepharose chromatography. The amounts of phosphorylated and dephosphorylated B50/GAP-43 forms were determined by electrophoresis, protein staining, and densitometry. Data on the relative phosphorylation of B50/GAP-43 protein in membrane and cytoplasmic fractions show a 10-fold difference in the ratio of cytoplasmic/membrane phosphorylation of B50/GAP-43 in AD brains with high neurofibrillary tangle (NFT) density compared to AD brains with low NFT density. This difference is due to a decreased percentage of phosphorylated B50/GAP-43 in the membrane fraction relative to that in the cytosolic fraction from high NFT density. No analogous relationship was found between the phosphorylation of B50/GAP-43 and the density of neuritic plaques in the brains examined. These data indicate differential distribution of phosphorylated and dephosphorylated B50/GAP-43 in normal and AD brains is related to NFT density but not to neuritic plaque density.
Aged↗
Derivation of completely cell culture-derived mice from early-passage embryonic stem cells.
Several newly generated mouse embryonic stem (ES) cell lines were tested for their ability to produce completely ES cell-derived mice at early passage numbers by ES cell <==> tetraploid embryo aggregation. One line, designated R1, produced live offspring which were completely ES cell-derived as judged by isoenzyme analysis and coat color. These cell culture-derived animals were normal, viable, and fertile. However, prolonged in vitro culture negatively affected this initial totipotency of R1, and after passage 14, ES cell-derived newborns died at birth. However, one of the five subclones (R1-S3) derived from single cells at passage 12 retained the original totipotency and gave rise to viable, completely ES cell-derived animals. The total in vitro culture time of the sublines at the time of testing was equivalent to passage 24 of the original line. Fully potent early passage R1 cells and the R1-S3 subclone should be very useful not only for ES cell-based genetic manipulations but also in defining optimal in vitro culture conditions for retaining the initial totipotency of ES cells.
Animals↗
Non-injection methods for the production of embryonic stem cell-embryo chimaeras.
The simple aggregation of pluripotent ES cells with morulae-stage embryos can result in viable chimaeras at a similar frequency to that of blastocyst injection. The savings in time and equipment inherent in the aggregation techniques, however, make this approach well worth considering.
Animals↗
Selective coupling of methotrexate to peptide hormone carriers through a gamma-carboxamide linkage of its glutamic acid moiety: benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate activation in salt coupling.
A convenient synthetic method is described for the preparation of peptide-methotrexate (MTX) conjugates in which MTX is coupled selectively through the gamma-carboxyl group of its glutamic acid moiety to a free amino group in peptide analogs. The syntheses of a somatostatin analog-MTX conjugate (MTX-D-Phe-Cys-Tyr-D-Trp-Lys-Val-Cys-Thr-NH2) (AN-51) and two conjugates of analogs of luteinizing hormone-releasing hormone (LH-RH) with MTX [Glp-His-Trp-Ser-Tyr-D-Lys(MTX)-Leu-Arg-Pro-Gly-NH2] (AJ-04) and [Ac-Ser-Tyr-D-Lys(MTX)-Leu-Arg-Pro-NH-Et] AJ-51 are presented as examples. Benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate (BOP reagent) was used in the synthesis for activation of 4-amino-4-deoxy-N10-methylpteroic acid, which reacted with the potassium salt of glutamic acid alpha-tert-butyl ester in dimethyl sulfoxide to form the suitably protected MTX derivative. This synthesis provides an example of the high suitability of BOP reagent for the salt-coupling method. The selectively protected MTX derivative was then coupled to the different peptide carriers and deprotected under relatively mild conditions by trifluoroacetic acid. The conjugates of MTX with hormonal analogs are suitable for targeting to various tumors that possess receptors for the peptide moieties.
Amino Acid Sequence↗
Genome manipulation in embryonic stem cells.
Embryonic stem (ES) cells derived from pluripotent cells of the early mouse embryo provide a powerful tool for genome manipulation in mammals. Dominantly acting effects can be achieved by introducing constructs to misexpress or ectopically express a gene product, express an altered product or express antisense constructs. Use of ES cell chimeras to analyse the effects of such alterations may provide information not readily available from transgenic mice. However, the most important use of ES cells, to date, is in the generation of recessive mutations, either in known genes by targeted mutagenesis or randomly by insertional mutagenesis. Examples of these approaches and possible future strategies are discussed.
Animals↗
Inhibition of growth of experimental prostate cancer in rats by LH-RH analogs linked to cytotoxic radicals.
The effects of hybrid cytotoxic LH-RH analogs, produced by linking anthraquinone or methotrexate to carrier LH-RH agonist [D-Lys6]LH-RH, were evaluated in Copenhagen-Fisher F1 rats bearing Dunning R-3327H prostate adenocarcinoma. The two cytotoxic LH-RH analogs T-98 [(D-Lys6)LH-RH coupled to glutaryl-2-(hydroxymethyl)anthraquinone (G-HMAQ)], and AJ-04 [(D-Lys6)LH-RH linked to methotrexate (MTX)], carrier [D-Lys6]LH-RH, or the free cytotoxic compounds MTX and G-HMAQ were administered from Alzet Osmotic minipumps for 7-8 weeks. The cytotoxic LH-RH analogs caused somewhat greater tumor growth inhibition than the carrier peptide, while anthraquinone or methotrexate alone, administered in equimolar doses, were ineffective. The inhibition of androgen sensitive organs (testes, ventral prostates, and seminal vesicles) was pronounced with both carrier and cytotoxic analogs, showing the latter to be fully hormonally active in suppressing the pituitary-gonadal axis. Histological changes were also evaluated. The inhibition of mitosis and the frequency of apoptosis were higher in tumors treated with AJ-04, T-98, [D-Lys6]LH-RH, or by castration than in those of controls. Serum hormone levels were lowered by both carrier peptide and cytotoxic analogs, LH being substantially depressed, and testosterone not detectable. These results and other findings indicate that LH-RH analogs containing cytotoxic radicals anthraquinone or methotrexate retain their hormonal activity after administration in vivo, and can effectively inhibit tumor growth. Extensive further studies are required on this new class of compounds, but apparent binding of cytotoxic LH-RH analogs to tumors such as prostate cancer, which have receptors for LH-RH, could greatly reduce peripheral toxicity of chemotherapeutic agents. This approach, based on targeted chemotherapy, might be of practical therapeutic importance for the management of advanced prostate cancers, which eventually relapse after palliative hormonal therapy.
Adenocarcinoma↗
Long-range analyses of the centromeric regions of human chromosomes 13, 14 and 21: identification of a narrow domain containing two key centromeric DNA elements.
Alpha-satellite, satellite 3 and satellite 1 DNA have been proposed as candidate components of a functional human centromere. Multiple subfamilies of these three DNA have recently been identified at the pericentric regions of the human acrocentric chromosomes. Using pulsed field gel electrophoresis, we have constructed long-range maps of the various centromeric markers for chromosomes 13, 14 and 21. These maps cover approximately 2.3 megabases of sequence for each chromosome, and the results demonstrate that within this centromeric region, chromosomes 13 and 21 have a similar organization that is partially shared by chromosome 14. A discrete satellite 3 domain was identified on each chromosome within the boundaries of the alpha-satellite DNA. No satellite 1 was detected within the defined centromeric regions suggesting that satellite 1 is not essential for centromere function.
Centromere↗