Underutilization of Aldosterone Antagonists in Heart Failure.

Background: Treatment with an aldosterone antagonist (AA) has been shown in multiple trials to reduce heart failure (HF)-related morbidity, mortality, and hospital readmission. American College of Cardiology Foundation (ACCF) and American Heart Association (AHA) treatment guidelines recommend the use of an AA in all HF patients with an ejection fraction ≤35% and no known contraindication. Several studies have documented underuse of AA. Objectives: To determine the proportion of patients who received AA therapy consistent with the ACCF/AHA guidelines. Secondary objectives included determining the proportion of patients who received an AA inconsistent with guidelines and 30- and 90-day readmission rates. Methods: A retrospective chart review was conducted of patients admitted to an inner city academic medical center with a diagnosis of HF between August 16, 2011, and June 5, 2013. Results: A total of 346 HF admissions (87.6% African American) were evaluated. Use of an AA at discharge was consistent with guidelines in 31% of patients. A total of 121 patients (35%) were discharged on an AA. Among the remaining 225 patients who were not discharged on an AA, 170 (75.6%) had no contraindication to therapy. Sixty-one patients were readmitted within 30 days, and a total of 108 patients were readmitted within 90 days. There were no significant differences in readmission rates between patients who were discharged on AA therapy and those who were not. Conclusion: AAs are still underutilized in the treatment of HF.

Relationship between nongenital tender point tenderness and intravaginal muscle pain intensity: ratings in women with provoked vestibulodynia and implications for treatment.

BACKGROUND: Vulvodynia is a chronic vulvar pain disorder and fibromyalgia is a chronic widespread musculoskeletal pain disorder, both of unknown etiology. Association of these conditions is well documented. Intravaginal algometer measurement of tenderness to pressure applied to the pelvic floor muscles helps define vulvodynia associated with musculoskeletal factors. Women with both vulvodynia and fibromyalgia might have increased pelvic muscle pain compared to women with vulvodynia alone, defining the possible link of these 2 conditions. OBJECTIVE: We sought to: (1) correlate pain intensity during the nongenital tender point tenderness examination to pain intensity with the vaginal algometer in women with provoked vestibulodynia, and (2) determine whether subjects with provoked vestibulodynia and fibromyalgia had higher pain intensity scores with the vaginal algometer than those without fibromyalgia. STUDY DESIGN: In all, 92 subjects referred for vulvar pain were confirmed to have provoked vestibulodynia using the cotton swab test. A diagnosis of fibromyalgia was made if pain was present (numeric rating scale >1) in at least 11 sites of the 18-point nongenital tender point tenderness exam. Vaginal pain sensitivity was measured using an intravaginal pressure algometer, where 0.1, 0.3, and 0.5 kg/cm2 forces were applied digitally in random assignment by force and location to the right and left iliococcygeus muscle regions and the posterior vaginal wall. Both tender point tenderness and algometer pain intensity were reported on a 0 (no pain) to 10 (worse pain) numeric rating scale. Correlations were computed between the composite pain intensity (total of rating scale from each pressure threshold at specified site) of nongenital and those of iliococcygeus regions and the posterior vaginal wall. Independent t tests were used to determine differences in iliococcygeus regions and the posterior vaginal algometer pain ratings and presence or absence of fibromyalgia. The significance level was at P < .05. The data were expressed as mean ± SD. RESULTS: A significant correlation was found between numeric rating scale pain scores on the nongenital tender point tenderness exam and algometer testing on the iliococcygeus region (r = 0.44, P < .0001) and the posterior vaginal wall (r = 0.45, P < .0001). Subjects with fibromyalgia by tender point tenderness had significantly higher iliococcygeal pain (6.14 ± 2.07 vs 3.74 ± 2.22, P = .0001) and posterior vaginal wall pain (5.67 ± 2.10 vs 3.07 ± 2.16, P < .0001) than women without fibromyalgia by tender point tenderness. CONCLUSION: Women with provoked vestibulodynia who experience more severe pain with nongenital tender point palpation also experience more deep vaginal pain on pelvic exam. Those who fulfill the diagnosis of fibromyalgia show significantly more intense deep vaginal pain to palpation of iliococcygeus muscles and posterior vaginal wall. Further research using a more precise definition of fibromyalgia is necessary to confirm this relationship, but findings suggest that women with provoked vestibulodynia coexisting with fibromyalgia have greater risk of superimposed vaginal muscle pain and may be candidates for early adjunctive pelvic floor physical therapy. These findings need to be explored in women with generalized, nonprovoked vulvodynia.

Inhaler Use in Hospitalized Patients with Chronic Obstructive Pulmonary Disease or Asthma: Assessment of Wasted Doses.

BACKGROUND: Hospitalized patients with chronic obstructive pulmonary disease (COPD) or asthma routinely have inhaled medications ordered for acute and maintenance therapy. Treatment may be administered via metered-dose inhaler (MDI) or dry-powder inhaler (DPI). These products must be appropriately labeled to be released home with the patient or discarded before discharge. OBJECTIVE: To assess the amount and estimated cost of wasted doses of medications via MDI or DPI for hospitalized patients with COPD/asthma. METHODS: A retrospective study was conducted at a university-affiliated hospital. Patients admitted between January 2011 and June 2012 with a primary diagnosis of COPD or COPD with asthma and who were ≥40 years of age were included. Information collected included use of albuterol, ipratropium, inhaled corticosteroids, long-acting beta agonist, or tiotropium and whether treatments were given by nebulizer, MDI, MDI plus valved holding chamber (VHC), or DPI. The number of doses dispensed, as well as doses not used, via MDI, MDI + VHC, or DPI were collected from electronic medical records. Costs associated with wasted medications were evaluated. RESULTS: Of 555 patient admissions screened, 478 (mean age, 66 years; 58% women; 74% African American) met study criteria. Of the total MDI or DPI doses dispensed, 87% were wasted, and associated hospital cost was approximately $86,973. CONCLUSIONS: Substantial waste of inhaled medications was found in our study. Practical strategies are needed to reduce wasted inhalers. Further assessment of this problem is needed in other US hospitals.

ATP-dependent mitochondrial porphyrin importer ABCB6 protects against phenylhydrazine toxicity.

Abcb6 is a mammalian mitochondrial ATP-binding cassette (ABC) transporter that regulates de novo porphyrin synthesis. In previous studies, haploinsufficient (Abcb6(+/-)) embryonic stem cells showed impaired porphyrin synthesis. Unexpectedly, Abcb6(-/-) mice derived from these stem cells appeared phenotypically normal. We hypothesized that other ATP-dependent and/or -independent mechanisms conserve porphyrins. Here, we demonstrate that Abcb6(-/-) mice lack mitochondrial ATP-driven import of coproporphyrin III. Gene expression analysis revealed that loss of Abcb6 results in up-regulation of compensatory porphyrin and iron pathways, associated with elevated protoporphyrin IX (PPIX). Phenylhydrazine-induced stress caused higher mortality in Abcb6(-/-) mice, possibly because of sustained elevation of PPIX and an inability to convert PPIX to heme despite elevated ferrochelatase levels. Therefore, Abcb6 is the sole ATP-dependent porphyrin importer, and loss of Abcb6 produces up-regulation of heme and iron pathways necessary for normal development. However, under extreme demand for porphyrins (e.g. phenylhydrazine stress), these adaptations appear inadequate, which suggests that under these conditions Abcb6 is important for optimal survival.

Chp1-Tas3 interaction is required to recruit RITS to fission yeast centromeres and for maintenance of centromeric heterochromatin.

The maintenance of centromeric heterochromatin in fission yeast relies on the RNA interference-dependent complexes RITS (RNA-induced transcriptional silencing complex) and RDRC (RNA-directed RNA polymerase complex), which cooperate in a positive feedback loop to recruit high levels of histone H3 K9 methyltransferase activity to centromeres and to promote the assembly and maintenance of centromeric heterochromatin. However, it is unclear how these complexes are targeted to chromatin. RITS comprises Chp1, which binds K9-methylated histone H3; Ago1, which binds short interfering (siRNAs); the adaptor protein Tas3, which links Ago1 to Chp1; and centromeric siRNAs. We have generated mutants in RITS to determine the contribution of the two potential chromatin-targeting proteins Chp1 and Ago1 to the centromeric recruitment of RITS. Mutations in Tas3 that disrupt Ago1 binding are permissive for RITS recruitment and maintain centromeric heterochromatin, but the role of Tas3's interaction with Chp1 is unknown. Here, we define the Chp1 interaction domain of Tas3. A strain expressing a tas3 mutant that cannot bind Chp1 (Tas3(Delta)(10-24)) failed to maintain centromeric heterochromatin, with a loss of centromeric siRNAs, a failure to recruit RITS and RDRC to centromeres, and high levels of chromosome loss. These findings suggest a pivotal role for Chp1 and its association with Tas3 for the recruitment of RITS, RDRC, and histone H3 K9 methyltransferase activity to centromeres.

Functional separation of the requirements for establishment and maintenance of centromeric heterochromatin.

The establishment and maintenance of centromeric heterochromatin in fission yeast require the RITS complex. Comprised of centromeric siRNAs, the chromodomain protein Chp1, Argonaute (Ago1), and Tas3, RITS couples the cellular RNAi pathway with assembly of constitutive heterochromatin. However, the mechanisms governing RITS-dependent establishment versus maintenance of centromeric heterochromatin remain unresolved. Here, we report that a mutant Tas3 protein that cannot bind Ago1 supports the maintenance of centromeric heterochromatin but cannot mediate efficient de novo establishment from cells transiently depleted for the histone H3 lysine 9 methyltransferase Clr4. In contrast, centromeric heterochromatin efficiently assembles in mutant cells transiently depleted for dicer. This mutant therefore allows ordering of the events leading to establishment of centromeric heterochromatin and places lysine 9 methylation of histone H3 upstream of dicer function.

Solution structure and dynamics of LuxU from Vibrio harveyi, a phosphotransferase protein involved in bacterial quorum sensing.

The marine bacterium Vibrio harveyi controls its bioluminescence by a process known as quorum sensing. In this process, autoinducer molecules are detected by membrane-bound sensor kinase/response regulator proteins (LuxN and LuxQ) that relay a signal via a series of protein phosphorylation reactions to another response regulator protein, LuxO. Phosphorylated LuxO indirectly represses the expression of the proteins responsible for bioluminescence. Integral to this quorum sensing process is the function of the phosphotransferase protein, LuxU. LuxU acts to shuttle the phosphate from the membrane-bound proteins, LuxN and LuxQ, to LuxO. LuxU is a 114 amino acid residue monomeric protein. Solution NMR was used to determine the three-dimensional structure of LuxU. LuxU contains a four-helix bundle topology with the active-site histidine residue (His58) located on alpha-helix C and exposed to solution. The active site represents a cluster of positively charged residues located on an otherwise hydrophobic protein face. NMR spin-relaxation experiments identify a collection of flexible residues localized on the same region of LuxU as His58. The studies described here represent the first structural characterization of an isolated, monomeric bacterial phosphotransferase protein.

Probing the molecular mechanisms of AZT drug resistance mediated by HIV-1 reverse transcriptase using a transient kinetic analysis.

Several hypotheses have been proposed to explain the development of resistance to the anti-HIV drug AZT. Clinical findings show that AZT resistance mutations in HIV-1 reverse transcriptase (RT) not only reduce susceptibility to thymidine analogues but may also confer multi-dideoxynucleoside resistance. In this report, we describe transient kinetic studies establishing the biochemical effects of AZT resistance mutations in HIV-1 RT on the incorporation and removal of natural and unnatural deoxynucleotides. While the physiological role remains to be elucidated, the largest biochemical difference between wild-type and AZT resistant HIV-1 RT manifested itself during ATP-mediated deoxynucleotide removal. Enhanced removal resulted from an increase in the maximum rate of chain terminator excision, suggesting that mutated residues play a role in the optimal alignment of substrates for ATP-mediated removal. The efficiency of pyrophosphorolysis was not increased by the presence of AZT resistance mutations. However, a 2-fold decrease in the extent of inhibition caused by the next correct nucleotide during pyrophosphorolytic cleavage of a D4TMP chain-terminated primer may illustrate how this mutant can utilize pyrophosphate to enhance resistance. The inability of RT to catalyze removal of a chain terminator from an RNA-RNA primer-template may show how slight changes in selectivity against AZTMP incorporation during the initiation of DNA synthesis can contribute to high-level resistance. Taken together, these results suggest that multiple modes of resistance may be conferred by these mutations. Structure-activity studies of chain terminator removal suggest that analogues that form tight interactions with residues in the RT active site may be more prone to resistance mechanisms mediated by removal.