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Myotonic dystrophy is a multisystemic neuromuscular disease caused by either a CTG repeat expansion inDMPK(DM1) or a CCTG repeat expansion inCNBP(DM2). Transcription of the expanded alleles produces toxic gain-of-function RNA that sequester the MBNL family of alternative splicing regulators into ribonuclear foci, leading to pathogenic mis-splicing. There are currently no approved treatments that target the root cause of disease which is the production of the toxic expansion RNA molecules. In this study, using our previously established HeLa DM1 repeat selective screening platform, we identified the natural product quercetin as a selective modulator of toxic RNA levels. Quercetin treatment selectively reduced toxic RNA levels and rescued MBNL dependent mis-splicing in DM1 and DM2 patient derived cell lines and in theHSALRtransgenic DM1 mouse model where rescue of myotonia was also observed. Based on our data and its safety profile for use in humans, we have identified quercetin as a priority disease-targeting therapeutic lead for clinical evaluation for the treatment of DM1 and DM2.One Sentence SummaryThe natural product quercetin reduces toxic RNA in myotonic dystrophy.

Properties of penetration of antifungals into the body compartments have been reviewed extensively by Felton et al. in 2014, so the goal of this review was to identify new data, including information on ibrexafungerp and rezafungin, in order to provide an updated pharmacotherapy approach in difficult-to-treat infections. Along with early identification and early initiation of treatment, assuring sufficient distribution into the infected site is essential for successful therapy. Although there are a limited number, the penetration and distribution of antifungals into organs and tissue are widely variable between agents and classes, and can be affected by factors such as weight, genetics, comorbidities, and inflammation. Clinicians should be aware of the challenges of tissue and organ penetration. Using existing human and animal data can help assure that penetration will be sufficient with the chosen antifungal prior to initiating therapy.

Purpose of review An intronic G4C2 expansion mutation in C9orf72 is the most common genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia (C9-ALS/FTD). Although there are currently no treatments for this insidious, fatal disease, intense research has led to promising therapeutic strategies, which will be discussed here. Recent findings Therapeutic strategies for C9-ALS/FTD have primarily focused on reducing the toxic effects of mutant expansion RNAs or the dipeptide repeat proteins (DPRs). The pathogenic effects of G4C2 expansion transcripts have been targeted using approaches aimed at promoting their degradation, inhibiting nuclear export or silencing transcription. Other promising strategies include immunotherapy to reduce the DPRs themselves, reducing RAN translation, removing the repeats using DNA or RNA editing and manipulation of downstream disease-altered stress granule pathways. Finally, understanding the molecular triggers that lead to pheno-conversion may lead to opportunities that can delay symptomatic disease onset. Summary A large body of evidence implicates RAN-translated DPRs as a main driver of C9-ALS/FTD. Promising therapeutic strategies for these devastating diseases are being rapidly developed with several approaches already in or approaching clinical trials.

A CTG repeat expansion in the DMPK gene is the causative mutation of myotonic dystrophy type 1 (DM1). Transcription of the expanded CTG repeat produces toxic gain-of-function CUG RNA, leading to disease symptoms. A screening platform that targets production or stability of the toxic CUG RNA in a selective manner has the potential to provide new biological and therapeutic insights. A DM1 HeLa cell model was generated that stably expresses a toxic r(CUG)480 and an analogous r(CUG)0 control from DMPK and was used to measure the ratio-metric level of r(CUG)480 versus r(CUG)0. This DM1 HeLa model recapitulates pathogenic hallmarks of DM1, including CUG ribonuclear foci and missplicing of pre-mRNA targets of the muscleblind (MBNL) alternative splicing factors. Repeat-selective screening using this cell line led to the unexpected identification of multiple microtubule inhibitors as hits that selectively reduce r(CUG)480 levels and partially rescue MBNL-dependent missplicing. These results were validated by using the Food and Drug Administration-approved clinical microtubule inhibitor colchicine in DM1 mouse and primary patient cell models. The mechanism of action was found to involve selective reduced transcription of the CTG expansion that we hypothesize to involve the LINC (linker of nucleoskeleton and cytoskeleton) complex. The unanticipated identification of microtubule inhibitors as selective modulators of toxic CUG RNA opens research directions for this form of muscular dystrophy and may shed light on the biology of CTG repeat expansion and inform therapeutic avenues. This approach has the potential to identify modulators of expanded repeat-containing gene expression for over 30 microsatellite expansion disorders.

Myotonic dystrophy type 1 (DM1) is caused by CTG nucleotide repeat expansions in the 3'-untranslated region (3'-UTR) of the dystrophia myotonica protein kinase (DMPK) gene. The expanded CTG repeats encode toxic CUG RNAs that cause disease, largely through RNA gain-of-function. DM1 is a fatal disease characterized by progressive muscle wasting, which has no cure. Regenerative medicine has emerged as a promising therapeutic modality for DM1, especially with the advancement of induced pluripotent stem (iPS) cell technology and therapeutic genome editing. However, there is an unmet need to identify in vitro outcome measures to demonstrate the therapeutic effects prior to in vivo clinical trials. In this study, we examined the muscle regeneration (myotube formation) in normal and DM1 myoblasts in vitro to establish outcome measures for therapeutic monitoring. We found normal proliferation of DM1 myoblasts, but abnormal nuclear aggregation during the early stage myotube formation, as well as myotube degeneration during the late stage of myotube formation. We concluded that early abnormal nuclear aggregation and late myotube degeneration offer easy and sensitive outcome measures to monitor therapeutic effects in vitro.

Repeat-associated non-ATG (RAN) proteins have been reported in 11 microsatellite expansion disorders but the factors that allow RAN translation to occur and the effects of different repeat motifs and alternative AUG-like initiation codons are unclear. We studied the mechanisms of RAN translation across myotonic dystrophy type 2 (DM2) expansion transcripts with (CCUG) or without (CAGG) efficient alternative AUG-like codons. To better understand how DM2 LPAC and QAGR RAN proteins are expressed, we generated a series of CRISPR/Cas9-edited HEK293T cell lines. We show that LPAC and QAGR RAN protein levels are reduced in protein kinase R (PKR)−/− and PKR-like endoplasmic reticulum kinase (PERK)−/− cells, with more substantial reductions of CAGG-encoded QAGR in PKR−/− cells. Experiments using mutant eIF2α-S51A HEK293T cells show that p-eIF2α is required for QAGR production. In contrast, LPAC levels were only partially reduced in these cells, suggesting that both non-AUG and close-cognate initiation occur across CCUG RNAs. Overexpression of the alternative initiation factor eIF2A increases LPAC and QAGR protein levels but, notably, has a much larger effect on QAGR expressed from CAGG-expansion RNAs that lack efficient close-cognate codons. The effects of eIF2A on increasing LPAC are consistent with previous reports that eIF2A affects CUG-initiation translation. The observation that eIF2A also increases QAGR proteins is novel because CAGG expansion transcripts do not contain CUG or similarly efficient close-cognate AUG-like codons. For QAGR but not LPAC, the eIF2A-dependent increases are not seen when p-eIF2α is blocked. These data highlight the differential regulation of DM2 RAN proteins and eIF2A as a potential therapeutic target for DM2 and other RAN diseases.

Background Patients labeled as penicillin allergic are more likely to receive second line non-β-lactam antibiotics, experience higher rates of treatment failure, and incur higher antibiotic costs. Fear of litigation has been identified as a reason clinicians avoid using β-lactams in a patient with a penicillin allergy. The systematic review objective is to describe medical negligence and malpractice cases in which known penicillin allergy patients received a β-lactam and experienced an adverse reaction. Methods Lexis-Nexus and Google Scholar were used to identify relevant legal cases. Variables collected from each case included date of publication, legal jurisdiction, date of injury, plaintiff and defendant demographics, health care setting, plaintiff clinical outcome, and legal outcome. Results Twenty-seven unique cases met inclusion criteria. The earliest case was published in 1959 and the most recent in 2013. The highest number of cases filed (n = 7) occurred in the most recent 10 year segment, from 2005 to 2015. Eighteen cases involved the receipt of a penicillin-based antibiotic; of these cases with a known legal outcome, the plaintiff (patient) prevailed or settled in 3 cases and defendants (providers) prevailed in 7 cases. Seven cases involved the receipt of a cephalosporin; of these cases with a known legal outcome, the plaintiff settled with physicians prior to trial in 1 case and defendants prevailed in 3 cases. Two cases involved the receipt of a carbapenem. Defendants prevailed in 1 case and the legal outcome of the other case is unknown. In cases where the defense successfully moved for summary judgment, judges cited a lack of scientific evidence demonstrating that a cephalosporin or carbapenem were contraindicated for a patient with a penicillin allergy. Conclusion The cases with published legal outcomes found limited professional liability and identify clear precedence for clinicians who prescribed cephalosporins or carbapenems to a patient with a known penicillin allergy. These results should decrease litigation fears of providers and risk managers within healthcare systems. Disclosures All authors: No reported disclosures.

Myotonic dystrophy type 1 (DM1) is caused by a CTG nucleotide repeat expansion within the 3′ UTR of the Dystrophia Myotonica protein kinase gene. In this study, we explored therapeutic genome editing using CRISPR/Cas9 via targeted deletion of expanded CTG repeats and targeted insertion of polyadenylation signals in the 3′ UTR upstream of the CTG repeats to eliminate toxic RNA CUG repeats. We found paired SpCas9 or SaCas9 guide RNA induced deletion of expanded CTG repeats. However, this approach incurred frequent inversion in both the mutant and normal alleles. In contrast, the insertion of polyadenylation signals in the 3′ UTR upstream of the CTG repeats eliminated toxic RNA CUG repeats, which led to phenotype reversal in differentiated neural stem cells, forebrain neurons, cardiomyocytes, and skeletal muscle myofibers. We concluded that targeted insertion of polyadenylation signals in the 3′ UTR is a viable approach to develop therapeutic genome editing for DM1., Myotonic dystrophy type 1 is caused by toxic RNAs with expanded CUG repeats in the 3′ UTR of the DMPK gene. Wang et al. developed a strategy to eliminate the toxic repeats by insertion of polyadenylation signals upstream of the expanded repeats for personalized cell-based therapy and in vivo therapeutic genome editing.

Microsatellite expansions cause more than 40 neurological disorders, including Huntington's disease, myotonic dystrophy, and C9ORF72 amyotrophic lateral sclerosis/frontotemporal dementia (ALS/FTD). These repeat expansion mutations can produce repeat-associated non-ATG (RAN) proteins in all three reading frames, which accumulate in disease-relevant tissues. There has been considerable interest in RAN protein products and their downstream consequences, particularly for the dipeptide proteins found in C9ORF72 ALS/FTD. Understanding how RAN translation occurs, what cellular factors contribute to RAN protein accumulation, and how these proteins contribute to disease should lead to a better understanding of the basic mechanisms of gene expression and human disease.

Repeat-associated non-AUG (RAN) translation is a noncanonical translation initiation event that occurs at nucleotide-repeat expansion mutations that are associated with several neurodegenerative diseases, including fragile X–associated tremor ataxia syndrome (FXTAS), ALS, and frontotemporal dementia (FTD). Translation of expanded repeats produces toxic proteins that accumulate in human brains and contribute to disease pathogenesis. Consequently, RAN translation constitutes a potentially important therapeutic target for managing multiple neurodegenerative disorders. Here, we adapted a previously developed RAN translation assay to a high-throughput format to screen 3,253 bioactive compounds for inhibition of RAN translation of expanded CGG repeats associated with FXTAS. We identified five diverse small molecules that dose-dependently inhibited CGG RAN translation, while relatively sparing canonical translation. All five compounds also inhibited RAN translation of expanded GGGGCC repeats associated with ALS and FTD. Using CD and native gel analyses, we found evidence that three of these compounds, BIX01294, CP-31398, and propidium iodide, bind directly to the repeat RNAs. These findings provide proof-of-principle supporting the development of selective small-molecule RAN translation inhibitors that act across multiple disease-causing repeats.

Eukaroytic RNA-binding proteins (RBPs) recognize and process RNAs through recognition of their sequence motifs via RNA-binding domains (RBDs). RBPs usually consist of one or more RBDs and can include additional functional domains that modify or cleave RNA. Engineered RBPs have been used to answer basic biology questions, control gene expression, locate viral RNA in vivo, as well as many other tasks. Given the growing number of diseases associated with RNA and RBPs, engineered RBPs also have the potential to serve as therapeutics. This review provides an in depth description of recent advances in engineered RBPs and discusses opportunities and challenges in the field. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Recognition RNA Methods > RNA Nanotechnology RNA in Disease and Development > RNA in Disease.

This review, one in a series on myotonic dystrophy (DM), is focused on the development and potential use of small molecules as therapeutics for DM. The complex mechanisms and pathogenesis of DM are covered in the associated reviews. Here, we examine the various small molecule approaches taken to target the DNA, RNA, and proteins that contribute to disease onset and progression in myotonic dystrophy type 1 (DM1) and 2 (DM2).

Microsatellite mutations involving the expansion of tri-, tetra-, penta-, or hexanucleotide repeats cause more than 40 different neurological disorders. Although, traditionally, the position of the repeat within or outside of an open reading frame has been used to focus research on disease mechanisms involving protein loss of function, protein gain of function, or RNA gain of function, the discoveries of bidirectional transcription and repeat-associated non-ATG (RAN) have blurred these distinctions. Here we review what is known about RAN proteins in disease, the mechanisms by which they are produced, and the novel therapeutic opportunities they provide.

In 2011, an intronic (G4C2)•(G2C4) expansion was shown to cause the most common forms of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). This discovery linked ALS with a clinically distinct form of dementia and a larger group of microsatellite repeat diseases, and catalyzed basic and translational research.

Significance A number of hereditary neurological and neuromuscular diseases are caused by the abnormal expansion of short tandem repeats, or microsatellites, resulting in the expression of repeat expansion RNAs and proteins with pathological properties. Although these microsatellite expansions may occur in either the coding or noncoding regions of the genome, trinucleotide CNG repeats predominate in exonic coding and untranslated regions while intron mutations vary from trinucleotide to hexanucleotide GC-rich, and A/AT-rich, repeats. Here, we use transcriptome analysis combined with complementary experimental approaches to demonstrate that GC-rich intronic expansions are selectively associated with host intron retention. Since these intron retention events are detectable in both affected tissues and peripheral blood, they provide a sensitive and disease-specific diagnostic biomarker.

Isavuconazonium sulfate is an orally or intravenously administered water-soluble prodrug that rapidly converts to the active triazole antifungal agent isavuconazole in the systemic circulation. Isavuconazole has broad antifungal activity that includes Candida, Aspergillus spp., and Mucorales. Isavuconazole offers several advantages over previous broad-spectrum triazole antifungals. The drug is well-absorbed from the oral capsule and does not appear to be significantly impacted by food intake or alterations in gastric acidity. The intravenous formulation does not require the use of a renally eliminated cyclodextrin carrier molecule. Isavuconazole displays linear pharmacokinetics with low interpatient variability in patients without hepatic insufficiency. The drug’s long half-life allows for once-daily dosing (loading doses are utilized when treating serious infections). Isavuconazole is generally well-tolerated. Adverse effects experienced in clinical trials included gastrointestinal effects, elevated hepatic enzymes, headache, and hypokalemia. The drug is subject to drug interactions, albeit at a lower rate than other broad-spectrum triazole antifungals.

The Eagle effect is a paradoxical growth phenomenon long known to exist in vitro with specific antimicrobial agents, particularly the penicillins. More recent reports have indicated that this effect also exists when Candida or Aspergillus species are exposed to the echinocandin antifungals. While the majority of data for this effect exists for caspofungin, there are also reports that micafungin and anidulafungin may have a paradoxical growth effect in certain media or with particular pathogens. In efforts to reproduce the paradoxical growth curve in vivo, results with Candida have been varied. In vivo studies suggest an effect with Aspergillus, but were not reproducible in vitro. Because of these results, questions have been raised about the clinical relevance of this phenomenon. Aside from select scenarios, including late clinical failure or catheter lock therapy, current data suggest that the clinical relevance of the paradoxical growth effect is not likely to be significant.

Myotonic dystrophy (DM) is a progressive, multisystem disorder affecting skeletal muscle, heart, and central nervous system. In both DM1 and DM2, microsatellite expansions of CUG and CCUG RNA repeats, respectively, accumulate and disrupt functions of alternative splicing factors, including muscleblind (MBNL) proteins. Grey matter loss and white matter changes, including the corpus callosum, likely underlie cognitive and executive function deficits in DM patients. However, little is known how cerebral cortical circuitry changes in DM. Here, flavoprotein optical imaging was used to assess local and contralateral responses to intracortical motor cortex stimulation in DM-related mouse models. In control mice, brief train stimulation generated ipsilateral and contralateral homotopic fluorescence increases, the latter mediated by the corpus callosum. Single pulse stimulation produced an excitatory response with an inhibitory-like surround response mediated by GABAA receptors. In a mouse model of DM2 (Mbnl2 KO), we observed prolonged and increased responsiveness to train stimulation and loss of the inhibition from single pulse stimulation. Conversely, mice overexpressing human MBNL1 (MBNL1-OE) exhibited decreased contralateral response to train stimulation and reduction of inhibitory-like surround to single pulse stimulation. Therefore, altering levels of two key DM-associated splicing factors modifies functions of local cortical circuits and contralateral responses mediated through the corpus callosum.

SummaryTranscription of expanded microsatellite repeats is associated with multiple human diseases, including myotonic dystrophy, Fuchs’ endothelial corneal dystrophy, andC9orf72-ALS/FTD. Eliminating or reducing production of RNA and proteins arising from these expanded loci holds therapeutic benefit. Here, we tested the hypothesis that a deactivated form of the Cas9 enzyme impedes transcription across expanded microsatellites. We observed a repeat length-, PAM-, and strand-dependent reduction in the abundance of repeat-containing RNAs upon targeting dCas9 directly to repeat sequences. Aberrant splicing patterns were rescued in DM1 cells, and production of RAN peptides characteristic of DM1, DM2, andC9orf72-ALS/FTD cells was drastically decreased. Systemic delivery of dCas9/gRNA by adeno-associated virus led to reductions in pathological RNA foci, rescue of chloride channel 1 protein expression, and decreased myotonia. These observations suggest that transcription of microsatellite repeat-containing RNAs is more sensitive to perturbation than transcription of other RNAs, indicating potentially viable strategies for therapeutic intervention.

Since the discovery of repeat-associated non-ATG (RAN) translation, and more recently its association with amyotrophic lateral sclerosis/frontotemporal dementia, there has been an intense focus to understand how this process works and the downstream effects of these novel proteins. RAN translation across several different types of repeat expansions mutations (CAG, CTG, CCG, GGGGCC, GGCCCC) results in the production of proteins in all three reading frames without an ATG initiation codon. The combination of bidirectional transcription and RAN translation has been shown to result in the accumulation of up to six mutant expansion proteins in a growing number of diseases. This process is complex mechanistically and also complex from the perspective of the downstream consequences in disease. Here we review recent developments in RAN translation and their implications on our basic understanding of neurodegenerative disease and gene expression.

Unexplained cardiovascular decompensation has been observed during central venous administration of some echinocandins.The purpose of this study was to assess cardiac toxicity associated with the echinocandins.Isolated rat hearts (Langendorff model) were perfused with anidulafungin (ANID), caspofungin (CASP), or micafungin (MICA) at exposures of 1, 4, and 10 times therapeutic concentrations. Changes in left ventricular contractility with experimental exposure were compared to control, and histologic and transmission electron microscopy (TEM) examinations of tissue were performed.Mean concentrations of ANID (10 - 80 µg/ml) and CASP (6 - 48 µg/ml) were associated with significant decreases in contractility (-77.1 ± 9.4% and -40.6 ± 15.6%, respectively; p0.05). MICA was associated with an increase in contractility (13.6 ± 2.8%, p = NS). On TEM, samples exposed to ANID and CASP had enlarged mitochondria and disintegrating myofibrils. Samples exposed to MICA showed some enlarged mitochondria.Mean concentrations of ANID and CASP were associated with statistically significant decreases in left ventricular contractility at concentrations that may be achievable in humans after peripheral administration, while MICA caused no change. TEM studies suggest this may be a result of mitochondrial damage. Caution may be warranted with central administration of these agents to patients with preexisting cardiac dysfunction.

Cardiac toxicity is an uncommon side effect of anti-fungal therapy. Until the recent reports of itraconazole (ITZ) associated cardiac failure, amphotericin was the antifungal most frequently reported with arrhythmias. We evaluated the cardiac effect of azole antifungals, specifically ITZ, and possible mechanisms of toxicity. Ex vivo live-heart studies were performed utilizing Sprague Dawley rats. Short exposure (25 (2 - 2.5 ug/mL) exposures, contractility decreased by 22.2% ± 15.7% and amplitude of left ventricular pressure decreased by 11% ± 0.17%. Electron micrograph and alterations in mitochondrial respiration suggest mitochondrial toxicity as an underlying mechanism. In conclusion, ITZ was associated with reductions in contractility, possibly secondary to mitochondrial dysfunction and dilated cardiomyopathy.

The echinocandins are membrane-anchored, cyclic lipopeptides (CLPs) with antifungal activity due to their ability to inhibit a glucan synthase located in the plasma membrane of fungi such as Candida albicans. A hydrophobic tail of an echinocandin CLP inserts into a membrane, placing a six-amino acid cyclic peptide near the membrane surface. Because processes critical for the function of the electron transfer complexes of mitochondria, such as proton uptake and release, take place near the surface of the membrane, we have tested the ability of two echinocandin CLPs, caspofungin and micafungin, to affect the activity of electron transfer complexes in isolated mammalian mitochondria. Indeed, caspofungin and micafungin both inhibit whole chain electron transfer in isolated mitochondria at low micromolar concentrations. The effects of the CLPs are fully reversible, in some cases simply via the addition of bovine serum albumin to bind the CLPs via their hydrophobic tails. Each CLP affects more than one complex, but they still exhibit specificity of action. Only caspofungin inhibits complex I, and the CLP inhibits liver but not heart complex I. Both CLPs inhibit heart and liver complex III. Caspofungin inhibits complex IV activity, while, remarkably, micafungin stimulates complex IV activity nearly 3-fold. Using a variety of assays, we have developed initial hypotheses for the mechanisms by which caspofungin and micafungin alter the activities of complexes IV and III. The dication caspofungin partially inhibits cytochrome c binding at the low-affinity binding site of complex IV, while it also appears to inhibit the release of protons from the outer surface of the complex, similar to Zn(2+). Anionic micafungin appears to stimulate complex IV activity by enhancing the transfer of protons to the O2 reduction site. For complex III, we hypothesize that each CLP binds to the cytochrome b subunit and the Fe-S subunit to inhibit the required rotational movement of the latter.

Objective: The binding characteristics of the polyene antifungal amphotericin B (AmB) are still arguably unclear 50 years after the first human treatment. Our purpose was to investigate the dynamic of polyene cell associated binding using an AmB directed antibody. Methods: Ex vivo murine model and in vitro mammalian cells studies were utilized to assess the binding characteristics of AmB at human therapeutic concentrations. Balb/c mice administered a single dose of an AmB formulation were assessed using immunohistochemistry. Human mononuculear cells isolated after phlebotomy were assessed using transmission electron micrography. Results & Conclusions: Ex vivo studies demonstrated diffuse binding of AmB formulations, however, the sensitivity of the technique would not allow delineation of the antifungals' cellular binding. However, transmission electron micrography of in vitro cell cultures allowed apparent discrimination of cell associated binding and suggestions of intracellular trafficking within 2 hours of polyene exposure. One could hypothesize the observed characteristics and previously published literature are suggestive of binding to clathrin type receptors with internalization and processing by endosomes. Further work will be required to substantiate this hypothesis.

Fluorescence has recently been applied to the analysis of the molecular organization state of the polyene antibiotic amphotericin B (AmB) in solution or in lipid membranes. The polyene chain of AmB monomer gives rise to two fluorescence emissions; S(1)(2(1)A(g)) → S(0)(1(1)A(g)) between 500 and 700 nm, S(2)(1(1)B(u)) → S(0)(1(1)A(g)) between 400 and 500 nm. However, Raman scattering might interfere with the S(2) → S(0) emission fluorescence due to the weak fluorescence quantum yield and close proximity to the exciting lines. In fact, we show here that a change in the excitation wavelength results in a shift of three emission bands, an effect which excludes their assignment to fluorescence. These bands originate from the water Raman at 3382 cm(-1)and AmB resonance Raman at 1556 and 1153 cm(-1). As a consequence, some former conclusions on the molecular organization state of AmB should be reconsidered.

Expansions of repetitive DNA sequences cause numerous human neurological and neuromuscular diseases. Ongoing repeat expansions in patients can exacerbate disease progression and severity. As pathogenesis is connected to repeat length, a potential therapeutic avenue is to modulate disease by manipulating repeat expansion size--targeting DNA, the root-cause of symptoms. How repeat instability is mediated by DNA replication, repair, recombination, transcription and epigenetics may explain its contribution to pathogenesis and give insights into therapeutic strategies to block expansions or induce contractions.

Background:Management of fungal osteomyelitis is prolonged and frequently unsuccessful. Antifungal-impregnated cement is sometimes used as adjunctive therapy.Objective:To examine the release of antifungals from biodegradable and nonbiodegradable cement carriers.Methods:In vitro methods were used to assess antifungal drug release and antifungal activity of impregnated cements commonly used as adjunctive treatment of osteomyelitis. Cements included thermoplastic, nonbioactive polymers (polymethylmethacrylate [PMMA]) or bioactive agents (hydroxyapatite [HAP], β-tricalcium phosphate [β-TCP]) and were formed into spheres (beads).Results:Amphotericin B provided consistent supernatant concentrations (release), between 1.75 and 2.0 ug/mL, over 110 days from all bone cements. Flucytosine and fluconazole were observed for 33–42 days before becoming undetectable from a nonbioactive sphere and 18–22 days from a bioactive sphere. Serum concentrations for micafungin, terbinafine, and anidulafungin impregnated into PMMA rapidly became undetectable, regardless of the matrix used. Investigational β-TCP spheres prolonged release for fluconazole and micafungin, but had no effect on amphotericin B. Serum calcium concentrations decreased 60–80% in all HAP-impregnated drug sphere supernatants. Only amphotericin B–impregnated PMMA impacted supernatant calcium, decreasing concentrations by 50–60%. The antifungal-impregnated beads did not appear to be toxic to osteoblasts during 72 hours of exposure in tissue culture medium.Conclusions:Elution characteristics of most antifungals from bone cement spheres are probably not optima) for treatment of deep-seated fungal infections if a similar phenomenon of antifungal release manifests in vivo. Ceramic nonabsorbable impregnated devices must be removed after their lifespan expires and may necessitate another surgical procedure that can increase surgical risk and cost. Bioactive osteoconductive materials may provide a surgical alternative to nonabsorbable matrices. However, there have been no controlled trials demonstrating improved therapeutic outcomes with local therapy and assessing whether biodegradable materials act as a new focus for infection.

Thirteen Candida glabrata strains harboring a range of mutations in hot spot regions of FKS1 and FKS2 were studied. The mutations were linked to an echinocandin reduced susceptibility phenotype. Sequence alignments showed that 11 out of the 13 mutants harbored a mutation in FKS1 or FKS2 not previously implicated in echinocandin reduced susceptibility in C. glabrata . A detailed kinetic characterization demonstrated that amino acid substitutions in Fks1p and Fks2p reduced drug sensitivity in mutant 1,3-β- d -glucan synthase by 2 to 3 log orders relative to that in wild-type enzyme. These mutations were also found to reduce the catalytic efficiency of the enzyme ( V max ) and to influence the relative expression of FKS genes. In view of the association of FKS mutations and reduced susceptibility of 1,3-β- d -glucan synthase, an evaluation of the new CLSI echinocandin susceptibility breakpoint was conducted. Only 3 of 13 resistant fks mutants (23%) were considered anidulafungin or micafungin nonsusceptible (MIC > 2 μg/ml) by this criterion. In contrast, most fks mutants (92%) exceeded a MIC of >2 μg/ml with caspofungin. However, when MIC determinations were performed in the presence of 50% serum, all C. glabrata fks mutants showed MICs of ≥2 μg/ml for the three echinocandin drugs. As has been observed with Candida albicans , the kinetic inhibition parameter 50% inhibitory concentration may be a better predictor of FKS -mediated resistance. Finally, the close association between FKS1/FKS2 hot spot mutations provides a basis for understanding echinocandin resistance in C. glabrata .

Objectives: Based on the assertion that fluorescence spectroscopy detects dimers of the polyene antibiotic amphotericin B (AmB), this technique was recently proposed to analyse the interaction of the drug with cell membranes. However, contradictory results indicate that this ‘dimeric’ fluorescence might actually originate from polyene impurities. We used a highly purified AmB to challenge this last proposal. Methods: Comparison of the fluorescence of AmB from different origins was made in dimethyl sulphoxide (DMSO); concentration and sodium dodecyl sulphate (SDS) addition dependencies were analysed in water. Results: Excitation of fluorescence in the absorption band of the AmB monomer (around 410 nm) revealed no difference between the different samples, in contrast with what was observed by excitation in the absorption wavelengths of self-associated AmB (around 325 nm). Furthermore, in this latter case, no concentration dependence was observed, in DMSO or in water. SDS addition increased the fluorescence in water. Conclusions: The fluorescence of AmB observed by excitation in the absorption wavelengths of selfassociated species (around 325 nm) is explainable by the presence of impurities. Fluorescence is probably not appropriate for characterization of the drug interaction with cell membranes.

Restriction fragment length polymorphism (RFLP) analysis using a multilocus heat-inducible cytoplasmic heat-shock protein 70 (Hsp70) hybridization probe with EcoRI-digested genomic DNA was used in molecular typing of 129 Trichomonas vaginalis isolates. Results indicate that Trichomonas organisms exhibit considerable polymorphism in their Hsp70 RFLP patterns. Analysis of seven American Type Culture Collection reference strains and 122 clinical isolates, including 84 isolates from Jackson, Mississippi, 18 isolates from Atlanta, Georgia, and 20 isolates from throughout the United States, showed 105 distinct Hsp70 RFLP pattern subtypes for Trichomonas. Phylogenetic analysis of the Hsp70 RFLP data showed that the T. vaginalis isolates were organized into two clonal lineages. These results illustrate the substantial genomic diversity present in T. vaginalis and indicate that a large number of genetically distinct Trichomonas isolates may be responsible for human trichomoniasis in the United States.

Mannnose-binding lectin (MBL) binds oligosaccharides on the surface of microorganisms to form complexes that activate the complement cascade and facilitate phagocytosis. Teicoplanin and dalbavancin glycopeptide antibiotics possess N-acetyl glucosamine and mannose oligosaccharides that may bind MBL. Pharmaceuticals capable of binding to MBL may decrease clearance of significant pathogens such as yeast. An invasive candidemia murine model was utilized to evaluate differences in survival between mannose- and teicoplanin-treated groups compared to a control group administered normal saline. Three groups of BALB/c mice were injected with Candida albicans ATCC 44858 (1.4 x 10(6) CFU). Pharmaceutical agents were administered 2 h pre-infection and 8 h post-infection. In vivo cumulative survival at 52 h revealed 10%, 30% and 90% survival rates for mice administered mannose, teicoplanin, and saline, respectively. There was 0% survival for mice given mannose or teicoplanin at 56 h, compared with 70% for the normal saline treated mice at the same time point (P < 0.05). This in vivo study shows 'accelerated progression of infection' for Candida-inoculated mice exposed to mannose or teicoplanin compared to those given normal saline. Further, protein polyacrylamide gel electrophoresis studies suggested a potential MBL-drug interaction which may attenuate complement activation, opsonization and phagocytosis.

The etiology of cardiomyopathies are classified into 4 main groupings (dilated, hypertrophic, restrictive, and idiopathic) and can be mechanistically caused by myocarditis, conduction abnormalities, focal direct injury, or nutritional deficiency. Based on our review of this topic, evidence suggests that echinocandin-related cardiac dysfunction is a mitochondrial drug-induced disease caused by focal direct myocyte injury. With caspofungin or anidulafungin administration into the heart via central line, exposure is likely extreme enough to induce the acute toxicity. Chronic or low-dose exposure may lead to hypertrophic cardiomyopathy; however, only acute exposures have been explored to date.

Received 6 September 2006; accepted 6 September 2006;electronically published 13 September 2006.Author affiliations are listed at the end of the text.Reprints or correspondence: Dr. Elias J. Anaissie, MyelomaInstitute for Research and Therapy, University of Arkansasfor Medical Sciences, 4301 W. Markham, Slot 816, LittleRock, AR 72205 (anaissieeliasj@uams.edu).

Disease-causing repeat instability is an important and unique form of mutation that is linked to more than 40 neurological, neurodegenerative and neuromuscular disorders. DNA repeat expansion mutations are dynamic and ongoing within tissues and across generations. The patterns of inherited and tissue-specific instability are determined by both gene-specific cis-elements and trans-acting DNA metabolic proteins. Repeat instability probably involves the formation of unusual DNA structures during DNA replication, repair and recombination. Experimental advances towards explaining the mechanisms of repeat instability have broadened our understanding of this mutational process. They have revealed surprising ways in which metabolic pathways can drive or protect from repeat instability.

Study Objective. To determine the effects of amphotericin B deoxycholate and caspofungin on the release of histamine from human peripheral blood cells, mononuclear cells, and mast cells. Design. In vitro cell culture experiments. Setting. University medical center. Material. Cultured human mononuclear (THP-1) and mast (HMC-1) cells from five healthy volunteers. Measurements and Main Results. The cultured cells were incubated with increasing concentrations of amphotericin B deoxycholate, diphen-hydramine, amphotericin B deoxycholate plus diphenhydramine, caspofungin, caspofungin plus diphenhydramine, and the calcium ionophore A23187 for up to 24 hours. Histamine concentrations and histamine N-methyltransferase activity were determined at various time points throughout exposure. Cell viability was assessed by exclusion of erythrocin B. The A23187 increased histamine concentrations from baseline in peripheral blood and HMC-1 cells. No change in histamine concentrations was observed in response to amphotericin B deoxycholate, whereas caspofungin induced a significant increase in histamine release in peripheral blood cells and HMC-1 cells. No change in histamine concentrations was observed in THP-1 cells in response to any pharmacologic agent tested. Similarly, histamine N-methyltransferase activity in peripheral blood was not affected by amphotericin B deoxycholate, but was significantly decreased by caspofungin. Conclusion. Amphotericin B deoxycholate does not affect histamine concentrations or histamine N-methyltransferase activity in whole blood or HMC-1 cells, suggesting that the amphotericin B-induced infusion-related reaction is not a histamine-mediated event. Conversely, caspofungin increased histamine concentrations in whole blood and HMC-1 cells and inhibited histamine N-methyltransferase activity. These data suggest that infusion-related reactions associated with caspofungin may be mediated by histamine release secondary to caspofungin.

A randomized, blinded, multicenter trial was conducted to compare fluconazole (800 mg per day) plus placebo with fluconazole plus amphotericin B (AmB) deoxycholate (0.7 mg/kg per day, with the placebo/AmB component given only for the first 5-6 days) as therapy for candidemia due to species other than Candida krusei in adults without neutropenia. A total of 219 patients met criteria for a modified intent-to-treat analysis. The groups were similar except that those who were treated with fluconazole plus placebo had a higher mean (+/- standard error) Acute Physiology and Chronic Health Evaluation II score (16.8+/-0.6 vs. 15.0+/-0.7; P=.039). Success rates on study day 30 by Kaplan-Meier time-to-failure analysis were 57% for fluconazole plus placebo and 69% for fluconazole plus AmB (P=.08). Overall success rates were 56% (60 of 107 patients) and 69% (77 of 112 patients; P=.043), respectively; the bloodstream infection failed to clear in 17% and 6% of subjects, respectively (P=.02). In nonneutropenic subjects, the combination of fluconazole plus AmB was not antagonistic compared with fluconazole alone, and the combination trended toward improved success and more-rapid clearance from the bloodstream.

Study Objective. To evaluate the toxicity of amphotericin B deoxycholate formulations. Design. In vitro experiment. Setting. University research center. Material. Human mononuclear THP-1 cells. Intervention. The human mononuclear cells were exposed in vitro for 2 hours to the following deoxycholate formulations of amphotericin B, in 2.5- and 5-μ/ml concentrations: Apothecon, Pharmacia, Sigma, Gensia, Pharma-Tek, and VHA. Measurements and Main Results. Toxicity of the amphotericin B formulations were assessed by measuring interleukin (IL)-1β expression in an in vitro model. Amphotericin B content was measured by enzyme-linked immunosorbent assay (ELISA), and amphotericin A and B contents were assessed by spectrophotometry. Endotoxin contamination was evaluated in all reagents. Expression of IL-1β from Sigma, Pharmacia, and Pharma-Tek formulations was increased approximately 250%, 50%, and 25%, respectively, compared with amphotericin A. Amphotericin B content of Sigma, Pharmacia, Pharma-Tek, and Gensia formulations, as measured by ELISA, was increased approximately 450%, 200%, 200%, and 100%, respectively, compared with Apothecon. This variation could not be explained by differences in amphotericin A or B content as measured by spectrophotometry. Conclusion. Amphotericin B is obtained from a fermentation plant and manufactured as a pharmaceutical at different facilities. Both previous clinical observations and the current in vitro evaluation revealed significant differences among the formulations. Likely, other polyenes or pyrogenic toxins in differing amounts are in these formulations, thus explaining the variability in toxicity observed among the formulations.

Alterations in the length (instability) of gene-specific microsatellites and minisatellites are associated with at least 35 human diseases. This review will discuss the various cis-elements that contribute to repeat instability, primarily through examination of the most abundant disease-associated repetitive element, trinucleotide repeats. For the purpose of this review, we define cis-elements to include the sequence of the repeat units, the length and purity of the repeat tracts, the sequences flanking the repeat, as well as the surrounding epigenetic environment, including DNA methylation and chromatin structure. Gender-, tissue-, developmental- and locus-specific cis-elements in conjunction with trans-factors may facilitate instability through the processes of DNA replication, repair and/or recombination. Here we review the available human data that supports the involvement of cis-elements in repeat instability with limited reference to model systems. In diverse tissues at different developmental times and at specific loci, repetitive elements display variable levels of instability, suggesting vastly different mechanisms may be responsible for repeat instability amongst the disease loci and between various tissues.

Objectives The purpose of this study was to determine the effect of the echinocandin antifungals on the cardiac system, including cardiac output, blood pressure and heart rate, when administered in an in-vivo model. Methods The echinocandin antifungals were administered via central line to male Sprague–Dawley rats. Cardiac imaging and functional measurements were made using a high-resolution in-vivo imaging system. Statistical comparisons of the experimental antifungals versus saline control were made using a Student's t-test. Key findings In cardiac output (CO) measurements, caspofungin was associated with a bimodal distribution in results at 3 mg/kg. Those with little response, termed ‘non-vulnerable’ animals (n = 3) had no significant change in CO from baseline (−4.6 ± 10.7%). Other animals, termed ‘vulnerable’ animals (n = 3 at 3 mg/kg and those dosed at 6 mg/kg (n = 6)), experienced greater than 60% decrease in CO (−66.4 ± 13.1% at 3 mg/kg and −62.9 ± 13.0% at 6 mg/kg, P < 0.05). A dose of 5 mg/kg anidulafungin was associated with no significant changes in CO (−16.1 ± 26%), while 11.5 mg/kg decreased CO by 62.7 ± 19.4% from baseline (P < 0.05). With micafungin 1 mg/kg and 5 mg/kg doses, changes in CO were not significant (−16.7 ± 2.1% and −18.2 ± 1.9%, respectively). Conclusions These studies provide substantial evidence to support ex-vivo Langendorff and in-vitro mitochondrial studies demonstrating a similar pharmacological event. Clinical reports of similar effects also support these findings.

Amphotericin B (AMB) is an antifungal agent that possesses immunomodulatory properties that may contribute to its infusion-related toxicity and activity. It has previously been shown to induce the expression of genes encoding the cytokines interleukin (IL)-1 beta and tumour necrosis factor (TNF)-alpha and the chemokines IL-8 and macrophage inflammatory protein (MIP)-1 beta in the human monocytic cell line THP-1. In an effort to identify additional AMB-responsive genes, the gene expression profiles of both THP-1 cells and human peripheral blood mononuclear cells (hPBMCs) on exposure to AMB were assessed using cDNA microarray analysis. In addition to genes known to be AMB responsive, we found the genes encoding IL-1 alpha and MIP-1 alpha to be AMB responsive in both THP-1 cells and hPBMCs. Increases in MIP-1 alpha and MIP-1 beta were also observed in the supernatants of hPBMCs exposed to AMB. The expression of several genes in response to AMB was unique to either cell type. Furthermore, variability in gene expression in hPBMCs was observed between donors. These genes and respective gene products may have significance in the infusion-related toxicity and activity of AMB.

The disease-associated expansion of (CTG)*(CAG) repeats is likely to involve slipped-strand DNAs. There are two types of slipped DNAs (S-DNAs): slipped homoduplex S-DNAs are formed between two strands having the same number of repeats; and heteroduplex slipped intermediates (SI-DNAs) are formed between two strands having different numbers of repeats. We present the first characterization of S-DNAs formed by disease-relevant lengths of (CTG)*(CAG) repeats which contained all predicted components including slipped-out repeats and slip-out junctions, where two arms of the three-way junction were composed of complementary paired repeats. In S-DNAs multiple short slip-outs of CTG or CAG repeats occurred throughout the repeat tract. Strikingly, in SI-DNAs most of the excess repeats slipped-out at preferred locations along the fully base-paired Watson-Crick duplex, forming defined three-way slip-out junctions. Unexpectedly, slipped-out CAG and slipped-out CTG repeats were predominantly in the random-coil and hairpin conformations, respectively. Both the junctions and the slip-outs could be recognized by DNA metabolizing proteins: only the strand with the excess repeats was hypersensitive to cleavage by the junction-specific T7 endonuclease I, while slipped-out CAG was preferentially bound by single-strand binding protein. An excellent correlation was observed for the size of the slip-outs in S-DNAs and SI-DNAs with the size of the tract length changes observed in quiescent and proliferating tissues of affected patients-suggesting that S-DNAs and SI-DNAs are mutagenic intermediates in those tissues, occurring during error-prone DNA metabolism and replication fork errors.

Several microsatellite-expansion diseases are characterized by the accumulation of RNA foci and RAN proteins, raising the possibility of a mechanistic connection. We explored this question using myotonic dystrophy type 2, a multisystemic disease thought to be primarily caused by RNA gain-of-function effects. We demonstrate that the DM2 CCTG⋅CAGG expansion expresses sense and antisense tetrapeptide poly-(LPAC) and poly-(QAGR) RAN proteins, respectively. In DM2 autopsy brains, LPAC is found in neurons, astrocytes, and glia in gray matter, and antisense QAGR proteins accumulate within white matter. LPAC and QAGR proteins are toxic to cells independent of RNA gain of function. RNA foci and nuclear sequestration of CCUG transcripts by MBNL1 is inversely correlated with LPAC expression. These data suggest a model that involves nuclear retention of expansion RNAs by RNA-binding proteins (RBPs) and an acute phase in which expansion RNAs exceed RBP sequestration capacity, are exported to the cytoplasm, and undergo RAN translation. VIDEO ABSTRACT.

Background The purpose of this study was to evaluate the effect of a novel "yeast-in-blood" surveillance service on the timeliness of antifungal chemotherapy for candidemia. Methods Two hundred seven blood cultures positive for Candida species between July 1, 1994, and February 15, 2009, as identified by the microbiology positive culture log, were included in this retrospective chart review. Patients with a positive culture before July 1, 2008, were evaluated by the yeast-in-blood surveillance service and included as intervention cases (iC). After this time, those occurring after discontinuation of the service were included as nonintervention cases (NIC). The primary outcome measure was the time to antifungal therapy from the time of blood culture draw. secondary outcome measures included antifungal selection and time to antifungal prescription order from culture positivity. Results Median time to therapy was 58.9 ± 28.4hours and 41.3 ± 30.5hours for NIC and IC, respectively ( P = 0.001). Median time to prescription order was 3.0 ± 6.9hours for NIC versus 1.9 ± 3.9hours for IC. Candida albicans was the predominant organism identified (45.3% of NIC and 54.6% of IC). Treatment agents included an azole in 57.4% of NIC and 47.4% of IC, an echinocandin in 33.3% and 27.3% and a polyene in 5.7% and 27.8%, respectively. Conclusions Time to therapy and time to prescription were shorter in those evaluated by the surveillance service. These data suggest that a yeast surveillance service improves antifungal medication therapy initiation.

D2A21, a novel peptide antibiotic has in vitro activity against a wide spectrum of sexually transmitted diseases (STD). In this study we tested the hypothesis that intravaginal D2A21 would interfere with acquisition of Trichomonas vaginalis infection in a modified mouse model. T. vaginalis infections of estrogenized young mice pretreated with Lactobacillus vaginalis or Lactobacillus rhamnosus were more frequent and persistent than those in mice pre-treated with Lactobacillus gasseri or Lactobacillus acidophilus. One hundred percent T. vaginalis infection was achieved for 2-4 days post-challenge when intravaginal L. rhamnosus pre-treatments were given to estrogenized mice 48 hr prior to a single T. vaginalis challenge. Estrogenized mice pre-treated with L. rhamnosus were pre-medicated with intravaginal placebo gel, 0.5% or 2% D2A21 gel, or 500 microg/mL metronidazole gel prior to T. vaginalis challenge. Both 2% D2A21 and metronidazole gels were significantly more efficacious (10% or none infected) than placebo gel (53% infected) in preventing vaginal T. vaginalis infections in mice.

Amphotericin B is known to elicit immunomodulatory effects on neutrophil, monocyte, and lymphocyte function. It also has been shown to induce the release of proinflammatory cytokines from human monocytes and macrophages. Release of these cytokines has been associated with the infusion-related toxicity observed after administration of this drug. The present study demonstrates that amphotericin B increases mRNA for the chemokines interleukin (IL)‐8, monocyte chemoattractant protein (MCP)‐1, and macrophage inflammatory protein (MIP)‐1b, as well as the cell adhesion molecules intercellular adhesion molecule (ICAM)‐1 and CD44 in the human monocytic cell line THP-1. Amphotericin B increased the concentrations of IL-8, MCP-1, and MIP-1b in a dose-dependent fashion. Amphotericin B also induced expression of ICAM-1 but not CD44 in these cells. Production of these proteins in response to amphotericin B may play a role in the immunomodulatory activity and toxicity of this antifungal agent. Amphotericin B is an intravenously administered polyene antifungal antibiotic that acts against several fungal pathogens [1]. Unfortunately, amphotericin B is associated with a plethora of adverse drug reactions, including dose-dependent nephrotoxicity, with secondary anemia, hypokalemia, and hypomagnesemia, as well as cardiac arrhythmias and pulmonary leukostasis. The drug also is associated with infusion-related toxicity, including fever, chills, hypotension, and nausea [1]. Despite its adverse effects, it remains the treatment of choice for most systemic fungal infections. Amphotericin B is believed to exert its antifungal activity by binding to ergosterol in the fungal cell membrane. This interaction appears to cause pores in the membrane, allowing leakage of potassium and other cellular components. Although amphotericin B has greater affinity for ergosterol, it does have some affinity for cholesterol in the mammalian cell membrane. The toxicity of this agent is thought to be due to this amphotericin B‐cholesterol interaction [2]. The immunomodulatory properties of amphotericin B have been studied to some extent. The drug causes release of inter