Transitioning from intravenous to subcutaneous insulin in the medical intensive care unit.

Background: There is a paucity of studies on transitions from IV insulin infusion (IVII) to subcutaneous (SC) insulin in the medical ICU (MICU).

Methods: We conducted a retrospective study of patients admitted to the Cleveland Clinic MICU from June 2013 to January 2014 who received IVII. We compared blood glucose (BG) control between 3 cohorts based on timing of basal insulin dose: (1) NB (no basal), (2) IB (incorrect basal), (3) CB (correct basal) at 5 time points post-IVII discontinuation (1, 4, 8, 12, and 24h).

Beta 1-adrenergic receptor polymorphisms confer differential function and predisposition to heart failure.

Catecholamines stimulate cardiac contractility through beta(1)-adrenergic receptors (beta(1)-ARs), which in humans are polymorphic at amino acid residue 389 (Arg/Gly). We used cardiac-targeted transgenesis in a mouse model to delineate mechanisms accounting for the association of Arg389 with human heart failure phenotypes. Hearts from young Arg389 mice had enhanced receptor function and contractility compared with Gly389 hearts.

Hierarchy of polymorphic variation and desensitization permutations relative to beta 1- and beta 2-adrenergic receptor signaling.

Agonist-promoted desensitization of G-protein-coupled receptors results in partial uncoupling of receptor from cognate G-protein, a process that provides for rapid adaptation to the signaling environment. This property plays important roles in physiologic and pathologic processes as well as therapeutic efficacy. However, coupling is also influenced by polymorphic variation, but the relative impact of these two mechanisms on signal transduction is not known.

Polymorphisms of the beta1-adrenergic receptor predict exercise capacity in heart failure.

Background: Exercise performance in patients with congestive heart failure is partially dependent on cardiac beta1-adrenergic receptor (beta1AR) function. There are 2 common polymorphisms of the beta1AR gene that alter the encoded amino acids at positions 49 (Ser or Gly) and 389 (Gly or Arg) and alter receptor function in vitro. Their relevance to modification of cardiac function in heart failure is not known.

Amino acid 49 polymorphisms of the human beta1-adrenergic receptor affect agonist-promoted trafficking.

The signaling impact of a human beta1-adrenergic receptor (beta1 AR) polymorphism at residue 49 of the aminoterminus (Ser-to-Gly substitution) was studied by recombinantly expressing each receptor. The two receptors displayed identical agonist and antagonist binding affinities. Furthermore, basal and agonist-stimulated adenylyl cyclase activities were the same for these receptors as assessed in both cell types.