A synergistic role of IRP1 and FBXL5 proteins in coordinating iron metabolism during cell proliferation.

Iron-regulatory protein 1 (IRP1) belongs to a family of RNA-binding proteins that modulate metazoan iron metabolism. Multiple mechanisms are employed to control the action of IRP1 in dictating changes in the uptake and metabolic fate of iron. Inactivation of IRP1 RNA binding by iron primarily involves insertion of a [4Fe-4S] cluster by the cytosolic iron-sulfur cluster assembly (CIA) system, converting it into cytosolic aconitase (c-acon), but can also involve iron-mediated degradation of IRP1 by the E3 ligase FBXL5 that also targets IRP2. How CIA and FBXL5 collaborate to maintain cellular iron homeostasis through IRP1 and other pathways is poorly understood. Because impaired Fe-S cluster biogenesis associates with human disease, we determined the importance of FBXL5 for regulating IRP1 when CIA is impaired. Suppression of FBXL5 expression coupled with induction of an IRP1 mutant (IRP13C>3S) that cannot insert the Fe-S cluster, or along with knockdown of the CIA factors NUBP2 or FAM96A, reduced cell viability. Iron supplementation reversed this growth defect and was associated with FBXL5-dependent polyubiquitination of IRP1. Phosphorylation of IRP1 at Ser-138 increased when CIA was inhibited and was required for iron rescue. Impaired CIA activity, as noted by reduced c-acon activity, was associated with enhanced FBXL5 expression and a concomitant reduction in IRP1 and IRP2 protein level and RNA-binding activity. Conversely, expression of either IRP induced FBXL5 protein level, demonstrating a negative feedback loop limiting excessive accumulation of iron-response element RNA-binding activity, whose disruption reduces cell growth. We conclude that a regulatory circuit involving FBXL5 and CIA acts through both IRPs to control iron metabolism and promote optimal cell growth.

Risk of thromboembolic events after protocolized warfarin reversal with 3-factor PCC and factor VIIa.

Bleeding events and life-threatening hemorrhage are the most feared complications of warfarin therapy. Prompt anticoagulant reversal aimed at replacement of vitamin K-dependent clotting factors is essential to promote hemostasis. A retrospective cohort study of warfarin-treated patients experiencing a life-threatening hemorrhage treated with an institution-specific warfarin reversal protocol (postimplementation group) and those who received the prior standard of care (preimplementation group) was performed. The reversal protocol included vitamin K, 3-factor prothrombin complex concentrate, and recombinant factor VIIa. Demographic and clinical information, anticoagulant reversal information, and all adverse events attributed to warfarin reversal were recorded. A total of 227 patients were included in final analysis, 109 in the preimplementation group and 118 in the postimplementation group. Baseline patient characteristics were similar in both groups, with the exception of higher average Sequential Organ Failure Assessment scores in the postimplementation group (P = .0005). The most common indication for anticoagulation reversal was intraparenchymal hemorrhage. Prereversal international normalized ratios (INRs) were similar in both groups. Attainment of INR normalization to less than 1.4 was higher, and rebound INR was lower in the postimplementation group (P < .0001; P = .0013). Thromboembolic complications were significantly higher in the postimplementation group (P = .003). Elevated baseline Sequential Organ Failure Assessment score and mechanical valve as an indication for anticoagulation were independently associated with thrombotic complications (P = .005). A warfarin reversal protocol consisting of 3-factor prothrombin complex concentrate, recombinant factor VIIa, and vitamin K more consistently normalized INR values to less than 1.4 as compared to the prior standard of care in a diverse patient population. This success came at the cost of a 2-fold increase in risk of thromboembolic complications.

Assessing the Thermal Safety of a Li Metal Solid-State Battery Material Set Using Differential Scanning Calorimetry.

At the earliest stage of battery development, differential scanning calorimetry (DSC) of a sample with all battery cell stack materials can provide quantitative data on the reaction thermochemistry. The resulting quantitative thermochemical map of expected reactions upon heating can then guide chemistry and component development toward improved cell safety. In this work, we construct Li0.43CoO2 + C + PVDF|Li6.4La3Zr1.4Ta0.6O12|Li microcell DSC samples with capacity-matched electrodes and test to 500 °C. Notable observations are: (1) ∼74% of the O2 released from the Li0.43CoO2 cathode reacts with C to form CO2 rather than with molten Li to produce Li2O, (2) PVDF pyrolysis (>400 °C) releases HF gas that exothermically reacts with Li to form LiF, and (3) reactions involving oxygen (e.g., CO2 and Li2O formation) account for ∼60% of the total heat released, and reactions involving HF (e.g., LiF formation) account for ∼36% of the total heat released.

Medication adherence: pharmacist perspective.

OBJECTIVE: To provide pharmacists with a current, comprehensive review of medication adherence challenges and solutions. DATA SOURCES: A computerized search of the PubMed and Medline databases (through July 2008) identified English language review articles on medication adherence using the MeSH terms patient compliance or adherence and medication, drug regimen, or treatment. STUDY SELECTION: By the authors. DATA EXTRACTION: The results were filtered to include those published in pharmacy journals, and 117 publications were selected based on the content of their abstracts. The final version of this review article used 55 of the 117 publications. An additional 15 publications that provided examples of specific adherence issues were included. A vignette from the authors' experience was used as a case study. DATA SYNTHESIS: This article introduces the challenge of patient medication adherence, discusses the various methods by which to monitor medication adherence, describes various treatment- and condition-related barriers to adherence, and discusses the effectiveness of numerous adherence intervention strategies. CONCLUSION: Nonadherence to a medication regimen may have multiple underlying causes, some of which may be easier to address than others. Open discussion between the pharmacist and patient regarding barriers to adequate medication adherence, followed by a multifaceted, personalized intervention to address these barriers, plays a key role in encouraging patients to adhere to the recommendations of the health care team.

PGC-1a integrates a metabolism and growth network linked to caloric restriction.

Deleterious changes in energy metabolism have been linked to aging and disease vulnerability, while activation of mitochondrial pathways has been linked to delayed aging by caloric restriction (CR). The basis for these associations is poorly understood, and the scope of impact of mitochondrial activation on cellular function has yet to be defined. Here, we show that mitochondrial regulator PGC-1a is induced by CR in multiple tissues, and at the cellular level, CR-like activation of PGC-1a impacts a network that integrates mitochondrial status with metabolism and growth parameters. Transcriptional profiling reveals that diverse functions, including immune pathways, growth, structure, and macromolecule homeostasis, are responsive to PGC-1a. Mechanistically, these changes in gene expression were linked to chromatin remodeling and RNA processing. Metabolic changes implicated in the transcriptional data were confirmed functionally including shifts in NAD metabolism, lipid metabolism, and membrane lipid composition. Delayed cellular proliferation, altered cytoskeleton, and attenuated growth signaling through post-transcriptional and post-translational mechanisms were also identified as outcomes of PGC-1a-directed mitochondrial activation. Furthermore, in vivo in tissues from a genetically heterogeneous mouse population, endogenous PGC-1a expression was correlated with this same metabolism and growth network. These data show that small changes in metabolism have broad consequences that arguably would profoundly alter cell function. We suggest that this PGC-1a sensitive network may be the basis for the association between mitochondrial function and aging where small deficiencies precipitate loss of function across a spectrum of cellular activities.

Protocolized warfarin reversal with 4-factor prothrombin complex concentrate versus 3-factor prothrombin complex concentrate with recombinant factor VIIa.

INTRODUCTION: Life-threatening bleeding can complicate warfarin therapy. Rapid anticoagulant reversal via replacement of vitamin-K dependent clotting factors is essential for hemostasis. We compare two methods of rapid factor replacement for warfarin reversal. METHODS: A retrospective cohort study of warfarin-treated patients experiencing life-threatening bleeding who received a reversal protocol comprised of 4F PCC or 3F PCC and rFVIIa was performed. Demographic, clinical and anticoagulant reversal information, and all adverse events attributed to warfarin reversal were recorded. RESULTS: 195 patients were included in final analysis. While baseline demographics were similar between groups, the 3F-PCC group had a longer ICU LOS and higher in-hospital mortality (p < .01, .01). Pre-reversal INR was similar between both groups, but post-reversal INR was significantly lower in the 3F-PCC group, 0.8 versus 1.3 (p < .01). Significantly more patients experienced thromboembolic complications in the 3F-PCC group than the 4F-PCC group (p < .01). Receipt of rFVIIa was significantly associated with thromboembolic complications. DISCUSSION: A 4F PCC reversal strategy is efficacious in INR reversal and provides lower thromboembolic risk as compared to 3F PCC with rFVIIa.

Successful treatment of a massive metoprolol overdose using intravenous lipid emulsion and hyperinsulinemia/euglycemia therapy.

Adrenergic ß-antagonists, commonly known as ß-blockers, are prescribed for many indications including hypertension, heart failure, arrhythmias, and migraines. Metoprolol is a moderately lipophilic ß-blocker that in overdose causes direct myocardial depression leading to bradycardia, hypotension, and the potential for cardiovascular collapse. We describe the case of a 59-year-old man who intentionally ingested ~7.5 g of metoprolol tartrate. Initial treatment of bradycardia and hypotension included glucagon, atropine, dopamine, and norepinephrine. Despite these treatment modalities, the patient developed cardiac arrest. Intravenous lipid emulsion (ILE) and hyperinsulinemia/euglycemia (HIE) therapies were initiated during advanced cardiac life support and were immediately followed by return of spontaneous circulation. Further treatment included gastric lavage, activated charcoal, continued vasopressor therapy, and a repeat bolus of ILE. The patient was weaned off vasoactive infusions and was extubated within 24 hours. HIE therapy was continued for 36 hours after metoprolol ingestion. A urine ß-blocker panel using mass spectrometry revealed a metoprolol concentration of 120 ng/ml and the absence of other ß-blocking agents. To date, no clear treatment guidelines are available for ß-blocker overdose, and the response to toxic concentrations is highly variable. In this case of a life-threatening single-agent metoprolol overdose, the patient was successfully treated with HIE and ILE therapy. Due to the increasing frequency with which ILE and HIE are being used for the treatment of ß-blocker overdose, clinicians should be aware of their dosing strategies and indications.

Constitutive and agonist-dependent self-association of the cell surface human lutropin receptor.

The human lutropin receptor (hLHR) is a G protein-coupled receptor (GPCR) that plays an essential role in reproductive physiology. The present studies were undertaken to determine whether the hLHR self-associates. We show that high molecular weight complexes of the hLHR can be co-immunoprecipitated from 293 cells transfected with differentially tagged hLHRs. These complexes are detected only in extracts from cells that have been co-transfected and not in extracts combined from cells expressing only one form of tagged hLHR, confirming the in vivo self-association of the receptor. In transiently transfected cells, in which a small percentage of cells overexpress hLHR and most of the hLHR is located intracellularly in the ER, the self-associated hLHR is composed predominantly of immature hLHR. When cells were transiently co-transfected with wild-type hLHR and a misfolded mutant of the hLHR, a physical association of the ER-localized misfolded mutant with the immature hLHR was observed, resulting in a decreased cell surface expression of the wild-type receptor. In contrast, in stably transfected cells, where the majority of cells express receptor and there is much less intracellular accumulation of hLHR, the self-associated forms of the hLHR are composed predominantly of cell surface receptor. The abundance of cell surface hLHR dimers and oligomers, as detected on SDS gels, is increased further upon human choriogonadotropin treatment of the stably transfected cells. In addition to documenting the self-association of cell surface hLHR, our results underscore the importance of the cellular distribution of recombinant GPCR as it relates to the nature of the GPCR dimerization and oligomerization.