ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

Treffer pro Seite

Treffer 1 - 5 | 5 Treffer

Sortierung

Digitale Medien

Multivariate nonhomogeneous refinement equations (1999)

Dinsenbacher, Thomas B. ; Hardin, Douglas P.

Springer

The journal of Fourier analysis and applications 5 (1999), S. 589-597

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1531-5851

Schlagwort(e): 42C15 ; 39B99 ; multivariate ; nonhomogeneous ; refinement

Quelle: Springer Online Journal Archives 1860-2000

Thema: Mathematik

Notizen: Abstract We give necessary and sufficient conditions for the existence and uniqueness of compactly supported distribution solutionsf=(f 1,...,f r)T of nonhomogeneous refinement equations of the form $$f(x) = h(x) + \sum\limits_{\alpha \in A} {c_\alpha f(2x - \alpha )(x \in R^s )} $$ , where h=(h1,...,hr)Tis a compactly supported vector-valued multivariate distribution, A⊂Z+ s has compact support, and the coefficientsc α are real-valued r×r matrices. In particular, we find a finite dimensional matrix B, constructed from the coefficientsc α of the equation (I−B)q=p, where the vectorp depends on h. Our proofs proceed in the time domain and allow us to represent each solution regardless of the spectral radius of P(0):=2−s∑c α , which has been a difficulty in previous investigations of this nature.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF01257193

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

Digitale Medien

Post-receptor defect accounts for phosphorylase hypersensitivity in cultured diabetic cardiomyocytes (1992)

Buczek-Thomas, Jo Ann ; Jaspers, Stephen R. ; Miller, Thomas B.

Springer

Molecular and cellular biochemistry 117 (1992), S. 63-70

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1573-4919

Schlagwort(e): glycogen phosphorylase ; alloxan-diabetes ; cardiomyocytes ; G-protein

Quelle: Springer Online Journal Archives 1860-2000

Thema: Biologie , Chemie und Pharmazie , Medizin

Notizen: Abstract The basis for the hypersensitive response of glycogen phosphorylase to epinephrine stimulation was investigated in adult rat cardiomyocytes isolated from normal and alloxan-diabetic animals. To assess potential G-protein involvement in the response, normal and diabetic derived myocytes were incubated with either cholera or pertussis toxin prior to hormonal stimulation. Pretreatment of cardiomyocytes with cholera toxin resulted in a potentiated response to epinephrine stimulation whereas pertussis toxin did not affect the activation of this signaling pathway. To determine if the enhanced response of phosphorylase activation resulted from an alteration in adenylate cyclase activation, the cells were challenged with forskolin. After 3 hr in primary culture, diabetic cardiomyocytes exhibited a hypersensitive response to forskolin stimulation relative to normal cells. However, after 24 hr in culture, both normal and diabetic myocytes responded identically to forskolin challenge. The present data suggest that a cholera toxin sensitive G-protein mediates the hypersensitive response of glycogen phosphorylase to catecholamine stimulation in diabetic cardiomyocytes and this response which is present in alloxan-diabetic cells and is induced in vitro in normal cardiomyocytes is primarily due to a defect at a post-receptor site.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF00230411

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

Digitale Medien

Identification of the molecular basis for phosphorylase hypersensitivity in cultured diabetic cardiomyocytes (1995)

Buczek-Thomas, Jo Ann ; Miller, Thomas B.

Springer

Molecular and cellular biochemistry 145 (1995), S. 131-139

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1573-4919

Schlagwort(e): glycogen phosphorylase ; alloxan-diabetes ; cardiomyocytes ; cGMP ; phosphodiesterase

Quelle: Springer Online Journal Archives 1860-2000

Thema: Biologie , Chemie und Pharmazie , Medizin

Notizen: Abstract The focus of this study was to identify the molecular basis for the hypersensitive response of glycogen phosphorylase activation to epinephrine stimulation in alloxan diabetic-derived cardiomyocytes. Cyclic AMP levels were found not to be significantly different between normal and diabetic-derived cells while cGMP concentrations were found consistently to be significantly lower in diabetic-derived cells than in normal cells. Treatment with cyclic GMP analogues did not affect phosphorylase activation by epinephrine in normal cardiomyocytes whereas, IBMX, a nonselective phosphodiesterase inhibitor, had a significant effect on basal and agonist-stimulated phosphorylase activity in both normal and diabetic-derived cardiomyocytes. Differences in the time course for the rate of decay of phosphorylasea from agonist-stimulated to basal levels were observed between normal and diabetic cells. After 3 h in primary culture, phosphorylasea activity returned to basal levels more quickly in normal than in diabetic-derived cells while after 24 h in culture, the time for phosphorylasea decay was not significantly different between normal and diabetic myocytes and was longer than the 3 h response. After 3 h in primary culture, no significant difference in phosphorylase kinase activity was observed between normal and diabetic-derived cells exposed to epinephrine whereas, after 24 h in culture, phosphorylase kinase activity was significantly decreased in diabetic cells under basal and agonist-stimulated conditions. These data collectively suggest that the hypersensitive response of glycogen phosphorylase to epinephrine stimulation in diabetic-derived cardiomyocytes is not due to a defect present at the level of phosphorylase kinase but may, in part, result from an alteration in cardiac phosphodiesterase activity resulting from diminished intracellular cyclic GMP concentrations.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF00935485

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

Digitale Medien

The Order of Exposure of Tau to Signal Transduction Kinases Alters the Generation of “AD-Like” Phosphoepitopes (1999)

Shea, Thomas B. ; Cressman, Corrine M.

Springer

Cellular and molecular neurobiology 19 (1999), S. 223-233

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1573-6830

Schlagwort(e): tau ; kinases ; signal transduction ; Alzheimer's disease ; phosphorylation ; paired helical filaments

Quelle: Springer Online Journal Archives 1860-2000

Thema: Biologie

Notizen: Abstract 1. The individual and sequential influence of protein kinase C (PKC), protein kinase A (PKA) and mitogen-activated protein kinase (MAP kinase) on human brain tau was examined. 2. A range of PKC concentrations generated certain phosphoepitopes common with paired helical filaments. These epitopes were masked by higher PKC concentrations, suggesting the presence of multiple tau phosphorylation sites for which PKC exhibited differing affinities and/or conformational alterations in tau induced by sequential PKC-mediated phosphorylation. 3. Prior phosphorylation by PKC enhanced the nature and extent of AD-like tau antigenicity generated by subsequent incubation with MAP kinase yet inhibited that generated by subsequent incubation with PKA. 4. Dephosphorylation of tau prior to incubation with kinases significantly altered the influence of individual and multiple kinase incubation on tau antigenicity in a site-specific manner, indicating that prior in situ phosphorylation events markedly influenced subsequent cell-free phosphorylation. 5. In addition to considerations of the potential impact of tau phosphorylation by individual kinases, these findings extend previous studies which indicate that tau antigenicity, and, presumably, its behavior in situ, is influenced by the sequential and convergent influences of multiple kinases.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1023/A:1006977127422

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

Digitale Medien

Hyperactivation of Mitogen-Activated Protein Kinase Increases Phospho-Tau Immunoreactivity Within Human Neuroblastoma: Additive and Synergistic Influence of Alteration of Additional Kinase Activities (1999)

Ekinci, Fatma J. ; Shea, Thomas B.

Springer

Cellular and molecular neurobiology 19 (1999), S. 249-260

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1573-6830

Schlagwort(e): MAP kinase ; tau ; protein kinase C ; wortmannin ; PD98059 ; neuroblastoma ; Alzheimer's disease

Quelle: Springer Online Journal Archives 1860-2000

Thema: Biologie

Notizen: Abstract Mitogen-activated protein (MAP) kinase phosphorylates tau in cell-free analyses, but whether or not it does so within intact cells remains controversial. In the present study, microinjection of MAP kinase into SH-SY-5Y human neuroblastoma cells increased tau immunoreactivity toward the phosphodependent antibodies PHF-1 and AT-8. In contrast, treatment with a specific inhibitor of MAP kinase (PD98059) did not diminish “basal” levels of these immunoreactivities in otherwise untreated cells. These findings indicate that hyperactivation of MAP kinase increases phospho-tau levels within cells, despite that MAP kinase apparently does not substantially influence intracellular tau phosphorylation under normal conditions. These findings underscore that results obtained following inhibition of kinase activities do not necessarily provide an indication of the consequences accompanying hyperactivation of that same kinase. Several studies conducted in cell-free systems indicate that exposure of tau to multiple kinases can have synergistic effects on the nature and extent of tau phosphorylation. We therefore examined whether or not such effects could be demonstrated within these cells. Site-specific phospho-tau immunoreactivity was increased in additive and synergistic manners by treatment of injected cells with TPA (which activates PKC), calcium ionophore (which activates calcium-dependent kinases), and wortmannin (which inhibits PIP3 kinase). Alteration in total tau levels was insufficient to account for the full extent of the increase in phospho-tau immunoreactivity. These additional results indicate that multiple kinase activities modulate the influence of MAP kinase on tau within intact cells.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1023/A:1006981228331

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

Treffer 1 - 5 | 5 Treffer