In canine myocardium, the beta-subunit of the L-type Ca2+ channel is phosphorylated by cAMP dependent protein kinase in vitro as well as in vivo (Haase et al. FEBS Lett 335: 217-222, 1993). We have assessed the identity of the beta-subunit as well as its in vivo phosphorylation in representative experimental groups of catecholamine-challenged canine hearts. Adrenergic stimulation by high doses of both noradrenaline and isoprenaline induced rapid (within 20 sec) and nearly complete phosphorylation of the Ca2+ channel beta-subunit. Phosphorylation in vivo was about 4-fold higher as compared to untreated controls. When related to catecholamine-depleted (reserpine-treated) hearts noradrenaline and isoprenaline increased the in vivo phosphorylation of the beta-subunit even 8-fold. This phosphorylation correlated positively with tissue levels of cAMP, endogenous particulated cAMP-dependent protein kinase (PKA) and the rate of contractile force development dP/dtmax. The results imply the involvement of a PKA-mediated phosphorylation of the Ca2+ channel beta-subunit in the adrenergic stimulation of intact canine myocardium.

Animals↗

PubMedDate not supplied

Functions of zinc in signaling, proliferation and differentiation of mammalian cells.

Zinc is essential for cell proliferation and differentiation, especially for the regulation of DNA synthesis and mitosis. On the molecular level, it is a structural constituent of a great number of proteins, including enzymes of cellular signaling pathways and transcription factors. Zinc homeostasis in eukaryotic cells is controlled on the levels of uptake, intracellular sequestration in zinc storing vesicles ('zincosomes'), nucleocytoplasmic distribution and elimination. These processes involve the major zinc binding protein metallothionein as a tool for the regulation of the cellular zinc level and the nuclear translocation of zinc in the course of the cell cycle and differentiation. In addition, there is also increasing evidence for a direct signaling function for zinc on all levels of signal transduction. Zinc can modulate cellular signal recognition, second messenger metabolism, protein kinase and protein phosphatase activities, and it may stimulate or inhibit activities of transcription factors, depending on the experimental systems studied. Zinc has been shown to modify specifically the metabolism of cGMP, the activities of protein kinase C and mitogen activated protein kinases, and the activity of transcription factor MTF-1 which controls the transcription of the genes for metallothionein and the zinc transporter ZnT-1. As a conclusion of these observations new hypotheses regarding regulatory functions of zinc ions in cellular signaling pathways are proposed.

Animals↗

PubMedDate not supplied

Psychological support of children undergoing liver transplantation and their parents: a single-centre experience.

Children undergoing liver transplantation, and their parents, are regularly provided with psychological support by a team of social workers and psychologists in the Children's Hospital of the Medical School Hannover, Germany. We would like to highlight the structure of this psychosocial care and its development since the first liver transplantation in 1978. As most of the stress related to the procedures of transplantation is inevitable, emotional support provided by such a team approach is essential.

Adaptation, Psychological↗

PubMedDate not supplied

[Psychological problems in personal description. Report on a research project].

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Cognition↗