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Objectives: Ambulatory care sensitive conditions (ACSCs) are acute care diagnoses that could potentially be prevented through improved primary care. This study investigated how payments and charges for these ACSC visits differ by three hospital-based settings (outpatient, emergency department [ED], and inpatient) and examined differences in payments and charges by their physician and facility components.Methods: This was a secondary analysis of data (2005 through 2010) from the Medical Expenditure Panel Survey. Multiple linear regression models were used to assess differences in the mean-adjusted payments and charges for ACSC visits by clinical setting and further divided payments and charges into physician and facility components.Results: Of all ACSC visits from 2005 through 2010, 41% were outpatient visits, 36% were ED visits, and 23% were hospital admissions. After adjusting for patient demographics and comorbid conditions, charges for an inpatient ACSC visit were four times higher ($11,414 vs. $2,563) and payments were five times higher ($4,325 vs. $859) when compared to an ED visit. By comparison, charges for an ACSC ED visit were two times higher ($2,563 vs. $1,084) and payments 2.5 times higher ($859 vs. $341) relative to an ACSC visit managed in an outpatient hospital-based clinic. Across all clinical settings, hospital facility fees account for 77% to 94% of the charge differences and 81% to 93% of the payment differences.Conclusions: For hospital-based ACSC visits, inpatient hospitalizations are by far the most expensive. Finding ways to expand outpatient resources and improve the health management of the chronically ill may avoid conditions that lead to more expensive hospital-based encounters. Across all hospital-based settings, facility fees are the major contributor of expense.ACADEMIC EMERGENCY MEDICINE 2015;22:172-181

The ability to extinguish a viral population of fixed reproductive capacity by causing small changes in the mutation rate is referred to as lethal mutagenesis and is a corollary of population genetics theory. Here we show that coxsackievirus B3 (CVB3) exhibits reduced mutational robustness relative to poliovirus, manifesting in enhanced sensitivity of CVB3 to lethal mutagens that is dependent on the size of the viral population. We suggest that mutational robustness may be a useful measure of the sensitivity of a virus to lethal mutagenesis. RNA virus genomes are replicated at mutation rates orders of magnitude higher than DNA genomes (10, 27) and exist as heterogeneous populations of genetically distinct yet related genomes. Attempts to define these populations have relied upon population genetics theory (5,6,34,35); unfortunately, little empirical evidence exists validating these theories in vivo (30).Population genetics theory predicts a log-linear relationship between the genomic mutation rate and the fecundity (average number of progeny generated per infectious cycle) needed to avoid extinction and defines a theoretical "extinction threshold" (6). A corollary of this theory is lethal mutagenesis, the ability to drive a viral population to extinction by increasing the error frequency (13).A high mutation rate can negatively affect viral fitness and may drive a population to extinction. However, the deleterious effects of a high mutation rate may differ between viruses depending on their mutational robustness, i.e., the constancy of a phenotype in the face of deleterious mutations (26). A more robust population is able to minimize the deleterious effects of a high mutation rate by opting not to maximize fitness, a phenomenon termed "survival of the flattest" (35). Previous studies have suggested that the distributions of mutational effects between DNA and RNA virus genomes are similar (25). Therefore, the mutational robustness of a virus might be expected to be similar to that of closely related viruses.We investigated the mutational robustness of two closely related enteroviruses, poliovirus (PV) and coxsackievirus B3 (CVB3), which employ similar replication strategies and genome organizations and exhibit 59% polyprotein identity (74% similarity) as shown by BLAST analysis (GenBank accession numbers Q5UEA2 and P03300). To compare the characteristics of mutational robustness of these two viruses, we examined the response of PV (Mahoney) and of CVB3 (CVB3/0) to increasing concentrations of the mutagenic nucleoside ribavirin (Fig. 1A). Infection was performed under conditions that included a low multiplicity of infection (MOI) so that the cumulative effect of increased mutation frequency could be observed over two or more replicative cycles. CVB3 was observed to be considerably more sensitive than PV to ribavirin treatment at 0.5 mM or greater. Dramatically increased sensitivity was not observed under conditions of high MOI (Fig. 1B), consistent with the deleterious effect of mutation being reversed by populati...

As part of our studies of lethal viral mutagens, a series of 5-substituted cytidine analogues were synthesized and evaluated for antiviral activity. Among the compounds examined, 5-nitrocytidine was effective against poliovirus (PV) and coxsackievirus B3 (CVB3) and exhibited greater activity than the clinically employed drug ribavirin. Instead of promoting viral mutagenesis, 5-nitrocytidine triphosphate inhibited PV RNA-dependent RNA polymerase (K d = 1.1 ± 0.1 μM), and this inhibition is sufficient to explain the observed antiviral activity.Ribonucleoside analogues that enhance the basal mutation frequency of RNA viruses constitute a promising new class of antiviral therapeutics. Such compounds, termed lethal mutagens, accelerate viral mutagenesis to intolerable levels, resulting in "error catastrophe" and loss of viral viability. 1-9 The mechanism of antiviral activity for mutagenic ribonucleoside analogues typically involves (i) in vivo conversion to ribonucleotides facilitated by host cell enzymes, (ii) misincorporation into the viral genome by error-prone viral RNA-dependent RNA polymerases (RdRP a ), and (iii) indiscriminate nucleotide templating during genomic replication. Over successive rounds of replication, the accrual of excessive mutations forces the virus into "error catastrophe", and viral viability is lost. Previously, we demonstrated that ribavirin (1), a clinically employed antiviral drug, functions as a lethal mutagen against poliovirus (PV) 8 and hepatitis C virus. 10 Inspired by the known lethal mutagen for HIV, 5-hydroxy-2′-deoxycytidine (2), 6,9 we report here the antiviral evaluation activity of a suite of 5-substituted cytidine analogues (4-7).* To whom correspondence should be addressed. Phone: (814) 865-2969. Fax: (814) Hydroxylated cytosines, such as 5-hydroxycytosine, are hallmarks of oxygen radical induced DNA damage and early causative factors in genomic mutagenesis. 11 The addition of a hydroxyl moiety to the 5-position of cytosine alters the relative distribution of amino to imino nucleobase tautomers, thereby increasing the abundance of imino 5-hydroxycytosine, which can base-pair with adenine. 12-14 Mispairing of this oxidative lesion with A during DNA replication promotes transition mutations and consequential scrambling of the encoded genetic message. Oxidative DNA damage can also occur by the introduction of oxidized deoxycytidine triphosphates (dCTPs) into the genome during replication. The 5′-triphosphate of 2, a product of dCTP oxidation, is incorporated into DNA by Klenow DNA polymerase I. 15,16 Fortunately, the integrity of DNA is maintained by complex networks of repair machinery that target such forms of DNA damage. 17,18On the basis of its mutagenic capacity toward genomic DNA, 5-hydroxy-2′-deoxycytidine (2) has been evaluated as an antiviral lethal mutagen against the HIV retrovirus. 9 Treatment with 2 confers significant reductions in viral titer, including an increase in G to A substitutions in the gene-encoding reverse transcriptase (RT). 9 In addition,...

RNA viruses exhibit extraordinarily high mutation rates during genome replication. Nonnatural ribonucleosides that can increase the mutation rate of RNA viruses by acting as ambiguous substrates during replication have been explored as antiviral agents acting through lethal mutagenesis. We have synthesized novel N-6-substituted purine analogues with ambiguous incorporation characteristics due to tautomerization of the nucleobase. The most potent of these analogues reduced the titer of poliovirus (PV) and coxsackievirus (CVB3) over 1,000-fold during a single passage in HeLa cell culture, with an increase in transition mutation frequency up to 65-fold. Kinetic analysis of incorporation by the PV polymerase indicated that these analogues were templated ambiguously with increased efficiency compared to the known mutagenic nucleoside ribavirin. Notably, these nucleosides were not efficient substrates for cellular ribonucleotide reductase in vitro, suggesting that conversion to the deoxyriboucleoside may be hindered, potentially limiting genetic damage to the host cell. Furthermore, a high-fidelity PV variant (G64S) displayed resistance to the antiviral effect and mutagenic potential of these analogues. These purine nucleoside analogues represent promising lead compounds in the development of clinically useful antiviral therapies based on the strategy of lethal mutagenesis.Natural nucleotides exist as tautomers in solution, and tautomerization of the nucleobases in DNA has been recognized as a likely mutagenic mechanism ever since the double-helical structure of the DNA molecule was first deduced by Watson and Crick (33,36). The keto (for G and U) and amino (for A and C) tautomers of the natural nucleotides are the predominant species with tautomeric constants (K T ) on the order of 10 5 . However, tautomeric conversion to the rare enol or imino forms of the nucleobases can lead to altered hydrogen bonding specificity and thus mutagenesis through noncanonical basepairing interactions. This has become known as the "rare tautomer" hypothesis of mutation (19,29).The tautomerization of bases to yield ambiguous base-pairing properties has also been exploited in the design of novel nucleoside drugs, including 5-hydroxy-2Ј-deoxycytidine (22) and 5-aza-5,6-dihydro-2Ј-deoxycytidine (KP-1212) (18, 25) (Fig. 1A). However, attempts to design clinically useful antiviral compounds around this premise have met with only limited success (13,16,18,25).Nucleobases exhibiting multiple conformations due to rotation or tautomerization have received attention as potential antiviral agents acting through lethal mutagenesis (11,22). Since the discovery that ribavirin (Fig. 1B) can act as a lethal mutagen (7), likely through rotation of the exocyclic carboxamide moiety, the concept of lethal mutagenesis as an antiviral strategy has received considerable attention (5,11,12).Recently, we have demonstrated that the ribonucleoside analogue rP (Fig. 1C) can act as a potent mutagen of poliovirus (PV) in vitro (13). Tautomerization of the nucleobas...

Background Disparities in health among blacks and Hispanics compared to whites individuals exist for a number of health measures; however, the health profile of individuals who are both black and Hispanic is not well known. We sought to determine whether race and ethnicity have synchronous or independent effects on health-related outcomes. Methods We combined the National Health Interview Survey for 2000–2007 to identify 896 black Hispanics. We selected health-related outcomes where white Hispanics and non-Hispanic blacks significantly differed. We computed adjusted prevalence estimates for black Hispanics and compared them to determine whether their health-related outcomes more closely resemble white Hispanics or non-Hispanic blacks. All prevalence estimates were adjusted for age, sex, education, marital status, income and survey year. Results Black Hispanics’ health behaviours resembled white Hispanics or were similar to both white Hispanics and non-Hispanic blacks. For health services outcomes, they resembled non-Hispanic blacks. However, their health status was influenced by both race and ethnicity, with black Hispanics resembling both white Hispanic and non-Hispanic black people. Conclusion We conclude that health behaviour interventions incorporating knowledge of Hispanic cultures may be sufficient to reach black Hispanics. However, health services or health status, interventions targeted broadly to Hispanic people may not be sufficient. In some respects black Hispanic people comprise a distinct subgroup that may require targeted attention in public health interventions.

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