[Expression of HCN4 protein in ventricular outflow tract of rabbit with idiopathic ventricular tachycardia].

Objective: To confirm the existence of purkinje fibers in rabbit outflow tract tissue and explore the role of Hyperpolarization-Activated Cyclic Nucleotide-Gated Channel 4 (HCN4) protein in idiopathic ventricular tachycardia.

Methods: A total of ten New Zealand white rabbits were randomly selected to observe whether there were pukinje fibers in outflow tract by the methods of HE staining and immunohistochemical detection of midsize neurofilament (NF-M). Forty rabbits were randomly divided into four groups: normal control group (SO), ventricular tachycardia group (VT), ventricular tachycardia+ esmolol intervention group (VT+ ESM) and ventricular tachycardia+ ivabradine intervention group (VT+ IVA).

Effects of solutes on empirical phase diagrams of human fibroblast growth factor 1.

A variety of solutes are commonly used to increase the stability of protein in therapeutic formulations. An empirical phase diagram approach is used to evaluate the effects of different types of additives on the solution behavior of a protein of pharmaceutical interest, human fibroblast growth factor 1 (FGF-1). A specific stabilizer, heparin, and a nonspecific stabilizer, sucrose, were used in this work.

Characterization of TAT-mediated transport of detachable kinase substrates.

The conjugation of peptides derived from the HIV TAT protein to membrane-impermeant molecules has gained wide acceptance as a means for intracellular delivery. Numerous studies have addressed the mechanism of uptake and kinetics of TAT translocation, but the cytosolic concentrations and bioavailability of the transported cargo have not been well-characterized. The current paper utilizes a microanalytical assay to perform quantitative single-cell measurements of the concentration and accessibility of peptide-based substrates for protein kinase B (PKB) and Ca(2+)/calmodulin-activated kinase II.

A quantitative single-cell assay for protein kinase B reveals important insights into the biochemical behavior of an intracellular substrate peptide.

The introduction of peptides into living cells for the purpose of manipulating cellular biochemistry has become widespread throughout biology. However, little is known about the behavior of these short sequences of amino acids within cells, particularly those used as substrates or inhibitors for kinases and other enzymes. We utilized a quantitative, single-cell assay to demonstrate that an 11-amino acid peptide was efficiently phosphorylated by intracellular protein kinase B (PKB) in fibrosarcoma cell line HT1080 and in NIH-3T3 cells.

Separation of mixtures of acidic and basic peptides at neutral pH.

Mixtures of acidic and basic peptides composed of the phosphorylated and nonphosphorylated forms of peptide substrates for kinases and a phosphatase were separated by capillary electrophoresis (CE) in buffer conditions compatible with live mammalian cells. The separation of such mixtures was especially challenging given the high salt and neutral pH of the requisite physiologic buffers. Due to poor peak reproducibility in bare capillaries, several strategies were implemented to improve the electrophoretic separation of the peptide mixtures.