Access to appointments based on insurance status in Washington, D.C.

In the U.S., emergency departments see millions of patients requiring timely and adequate outpatient follow-up. Using a hypothetical patient presenting with a scripted presentation of hypertension evaluated in the emergency department and requiring close outpatient follow-up, randomly selected providers in the District of Columbia were queried by phone to evaluate their accessibility based on insurance status. Seventy one percent of calls for privately insured hypothetical patients resulted in a successful appointment. Medicaid fee-for-service was associated with a significantly lower rate of successful appointments (36.6%) than private insurance (p=.002.) Uninsured "patients" had only a 13% success rate when considering out-of-pocket payment limitations of less than $50 (p<.001 compared with private). Access to primary care follow-up is poor in the District of Columbia for all types of insurance; however people with Medicaid fee-for-service and the uninsured face especially strong barriers.

Lobe-dependent regulation of ryanodine receptor type 1 by calmodulin.

Calmodulin activates the skeletal muscle Ca(2+) release channel RYR1 at nm Ca(2+) concentrations and inhibits the channel at microm Ca(2+) concentrations. Using a deletion mutant of calmodulin, we demonstrate that amino acids 2-8 are required for high affinity binding of calmodulin to RYR1 at both nm and microm Ca(2+) concentrations and are required for maximum inhibition of the channel at microm Ca(2+) concentrations. In contrast, the addition of three amino acids to the N terminus of calmodulin increased the affinity for RYR1 at both nm and microm Ca(2+) concentrations, but destroyed its functional effects on RYR1 at nm Ca(2+). Using both full-length RYR1 and synthetic peptides, we demonstrate that the calmodulin-binding site on RYR1 is likely to be noncontiguous, with the C-terminal lobe of both apocalmodulin and Ca(2+)-calmodulin binding to amino acids between positions 3614 and 3643 and the N-terminal lobe binding at sites that are not proximal in the primary sequence. Ca(2+) binding to the C-terminal lobe of calmodulin converted it from an activator to an inhibitor, but an interaction with the N-terminal lobe was required for a maximum effect on RYR1. This interaction apparently depends on the native sequence or structure of the first few amino acids at the N terminus of calmodulin.