The cGMP-Dependent Protein Kinase II Is an Inhibitory Modulator of the Hyperpolarization-Activated HCN2 Channel

Opening of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels is facilitated by direct binding of cyclic nucleotides to a cyclic nucleotide-binding domain (CNBD) in the C-terminus. Here, we show for the first time that in the HCN2 channel cGMP can also exert an inhibitory effect on gating via cGMP-dependent protein kinase II (cGKII)-mediated phosphorylation. Using coimmunoprecipitation and immunohistochemistry we demonstrate that cGKII and HCN2 interact and colocalize with each other upon heterologous expression as well as in native mouse brain. We identify the proximal C-terminus of HCN2 as binding region of cGKII and show that cGKII phosphorylates HCN2 at a specific serine residue (S641) in the C-terminal end of the CNBD. The cGKII shifts the voltage-dependence of HCN2 activation to 2–5 mV more negative voltages and, hence, counteracts the stimulatory effect of cGMP on gating. The inhibitory cGMP effect can be either abolished by mutation of the phosphorylation site in HCN2 or by impairing the catalytic domain of cGKII. By contrast, the inhibitory effect is preserved in a HCN2 mutant carrying a CNBD deficient for cGMP binding. Our data suggest that bidirectional regulation of HCN2 gating by cGMP contributes to cellular fine-tuning of HCN channel activity

Identification and Characterization of Novel Mutations in the Human Gene Encoding the Catalytic Subunit Calpha of Protein Kinase A (PKA)

The genes PRKACA and PRKACB encode the principal catalytic (C) subunits of protein kinase A (PKA) Cα and Cβ, respectively. Cα is expressed in all eukaryotic tissues examined and studies of Cα knockout mice demonstrate a crucial role for Cα in normal physiology. We have sequenced exon 2 through 10 of PRKACA from the genome of 498 Norwegian donors and extracted information about PRKACA mutations from public databases. We identified four interesting nonsynonymous point mutations, Arg45Gln, Ser109Pro, Gly186Val, and Ser263Cys, in the Cα1 splice variant of the kinase. Cα variants harboring the different amino acid mutations were analyzed for kinase activity and regulatory (R) subunit binding. Whereas mutation of residues 45 and 263 did not alter catalytic activity or R subunit binding, mutation of Ser109 significantly reduced kinase activity while R subunit binding was unaltered. Mutation of Cα Gly186 completely abrogated kinase activity and PKA type I but not type II holoenzyme formation. Gly186 is located in the highly conserved DFG motif of Cα and mutation of this residue to Val was predicted to result in loss of binding of ATP and Mg2+, which may explain the kinetic inactivity. We hypothesize that individuals born with mutations of Ser109 or Gly186 may be faced with abnormal development and possibly severe disease

Risk of breast cancer in young women in relation to body size and weight gain in adolescence and early adulthood

Findings have been inconsistent on effects of adolescent body size and adult weight gain on risk of breast cancer in young women. These relations were examined in a population-based case control study of 1590 women less than 45 years of age newly diagnosed with breast cancer during 1990–1992 in three areas of the US and an age-matched control group of 1390 women. Height and weight were measured at interview and participants asked to recall information about earlier body size. Logistic regression was used to estimate the relative risk of breast cancer adjusted for other risk factors. Women who were either much heavier or lighter than average in adolescence or at age 20 were at reduced risk. Weight gain after age 20 resulted in reduced risk, but the effect was confined to early-stage and, more specifically, lower grade breast cancer. Neither the risk reduction nor the variation by breast cancer stage or grade was explained by the method of cancer detection or by prior mammography history. These findings suggest that relations between breast cancer risk in young women and body weight at different ages is complex and that the risk reduction with adult weight gain is confined to less aggressive cancers. © 1999 Cancer Research Campaig

Optimizing Resident Clinic Efficiency Through Process Flow Analysis

Abstract Introduction: Clinic process inefficiencies cause lengthy visit and wait times, which frustrate patients and providers and limit clinic capacity Objective: To identify process inefficiencies and assess process flow interventions Methods: Prospective, consecutive series of resident clinic visits over a 3-week period after transferring refraction from tech to resident. Personnel recorded the time spent waiting for and undergoing each clinic process. The clinic also piloted a “Fast Track” from registration to resident for appropriate established patients. Results: Patients spent 53% of the visit waiting, primarily for the tech. Transferring refraction from tech to resident decreased the wait for tech and tech duration without increasing resident duration. There was no significant reduction in total visit or wait times. “Fast Track” decreased total visit time by 38% but comprised only 3.5% of visits that may have been appropriate. Conclusion: Reallocating a task from the slowest process decreased that process’s wait and duration but had no effect on total visit or wait times. Process flow analysis identifies inefficiencies and assesses interventions. Automated data collection is crucial for iterations.https://jdc.jefferson.edu/patientsafetyposters/1125/thumbnail.jp

Is Shared Decision Making for End-of-Life Decisions Associated With Better Outcomes as Compared to Other Forms of Decision Making? A Systematic Literature Review

Background: Whether shared decision making (SDM) has been evaluated for end-of-life (EOL) decisions as compared to other forms of decision making has not been studied. Purpose: To summarize the evidence on SDM being associated with better outcomes for EOL decision making, as compared to other forms of decision making. Data Sources: PubMed, Web of Science, Cochrane Central Register of Controlled Trials, EMBASE, PsycINFO, and CINAHL databases were searched through April 2014. Study Selection: Studies were selected that evaluated SDM, compared to any other decision making style, for an EOL decision. Data Extraction: Components of SDM tested, comparators to SDM, EOL decision being assessed, and outcomes measured. Data Synthesis: Seven studies met the inclusion criteria (three experimental and four observational studies). Results were analyzed using narrative synthesis. All three experimental studies compared SDM interventions to usual care. The four observational studies compared SDM to doctor-controlled decision making, or reported the correlation between level of SDM and outcomes. Components of SDM specified in each study differed widely, but the component most frequently included was presenting information on the risks/benefits of treatment choices (five of seven studies). The outcome most frequently measured was communication, although with different measurement tools. Other outcomes included decisional conflict, trust, satisfaction, and “quality of dying.” Limitations: We could not analyze the strength of evidence for a given outcome due to heterogeneity in the outcomes reported and measurement tools. Conclusions: There is insufficient evidence supporting SDM being associated with improved outcomes for EOL decisions as opposed to other forms of decision making. Future studies should describe which components of SDM are being tested, outline the comparator decision making style, and use validated tools to measure outcomes