Paradoxical Decrease Research Articles

Real-Time Quantitative Measurements of Foot Perfusion in Patients With Critical Limb Ischemia.

Current methods of evaluating adequacy of endovascular procedures are imperfect and do not always predict which patients will do well. The purpose of this study was to evaluate the role of real-time quantitative measurements of perfusion among patients with critical limb ischemia. Thirty-four patients with critical limb ischemia undergoing endovascular treatment were recruited. Perfusion Images of the foot were obtained pre and post successful angioplasty using an SPY Elite System (Novadaq Technologies, Ontario, Canada). Patients were followed for 6 months. Subsequently a logistic regression was performed to determine whether intraprocedural perfusion parameters predicted the odds of wound healing. Twenty-nine patients had successful angioplasty. Median age was 69.5% ± 8.3; 75% were men and 64% were diabetic. Rutherford stages were (4%-39%, 5%-57%, 6%-4%), and the average target limb ankle-brachial index (ABI) was 0.58 (SD 2.24). There was no significant correlation between the ABI and perfusion parameters. Inflow perfusion rate correlated significantly with Rutherford stage (Spearman rho 0.398, P = .036). After successful angioplasty 39% had a decrease in inflow rate and 57% had a decreased total inflow. In all, 25 patients completed 6 months of follow-up. Resolution of rest pain and/or healing of the ischemic wound occurred in 10 (40%) patients at 1 month, 4 (16%) at 3 months, and 2 (8%) at 6 months. One patient underwent a major amputation at 2 months. Eight (32%) patients never healed or had persistent rest pain. None of the real-time perfusion variables were significant predictors of wound healing. Many patients experience a paradoxical decrease in perfusion following successful angioplasty suggesting perfusion may not correlate with angiographic outcome, possibly due to microemboli, microvascular disease, or vasospasm. Real-time perfusion imaging following intra-arterial infusion of indocyanine green does not predict the odds of wound healing.

Long-term stimulation of cardiac vagal preganglionic neurons reduces blood pressure in the spontaneously hypertensive rat.

Arterial hypertension is associated with autonomic nervous system dysfunction. Different interventional strategies have been implemented in recent years for the reduction of sympathetic activity in patients with hypertension. However, the therapeutic benefit of increasing vagal tone in hypertensive patients remains largely unexplored. Here, we describe the effects of long-term activation of vagal neural pathways on arterial pressure, heart rate arterial pressure variability and spontaneous baroreflex sensitivity in spontaneously hypertensive rats (SHR) and normotensive Wistar rats. Brainstem vagal preganglionic neurons residing in the dorsal vagal motor nucleus (DVMN) were targeted with a lentiviral vector to induce the expression of an artificial G(s) protein-coupled receptor termed designer receptors exclusively activated by designer drugs (DREADD-Gs). The transduced neurons were activated daily by systemic administration of otherwise inert ligand clozapine-n-oxide. Arterial pressure measurements were recorded in conscious freely moving animals after 21 consecutive days of DVMN stimulation. Resting arterial pressure was significantly lower in SHRs expressing DREADD-Gs in the DVMN, compared with control SHRs expressing enhanced green fluorescent protein. No changes in arterial pressure were detected in Wistar rats expressing DREADD-Gs compared with rats expressing enhanced green fluorescent protein in the DVMN. Pharmacogenetic activation of DREADD-Gs-expressing DVMN neurons in SHRs was accompanied with increased baroreflex sensitivity and a paradoxical decrease in cardio-vagal components of heart rate and systolic arterial pressure variability in SHRs. These results suggest that long-term activation of vagal parasympathetic pathways is beneficial in restoring autonomic balance in an animal model of neurogenic hypertension and might be an effective therapeutic approach for the management of hypertension.

316 - Paradoxical disruption of Nrf2 signaling despite mitochondrial iron driven oxidative stress in Friedreich’s ataxia cardiomyopathy

Cardiomyopathy is the leading cause of mortality for the most prevalent inherited ataxia, Friedreich’s ataxia (FA). Deficient expression of the mitochondrial protein frataxin that is crucial for mitochondrial iron metabolism is the cause of FA, which exhibits marked mitochondrial Fe accumulation. Our studies using a conditional cardiac frataxin knockout (KO) mouse that mirrors FA cardiomyopathy have shown frataxin deletion leads to pronounced trafficking of cardiac iron from the cytosol to the mitochondrion, leading to a cytosolic iron-deficiency and mitochondrial iron accumulation in the form of non-protein-bound, biomineral iron aggregates. The ensuing oxidative stress is likely a key contributor to FA pathology. The transcription factor, nuclear factor E2-related factor 2 (Nrf2), is the master regulator of cellular antioxidant response. In the frataxin KO mouse, our studies demonstrated increased protein and GSH oxidation in the KO relative to wild-type (WT) littermates. Despite this, we found paradoxical decreases in total and nuclear Nrf2 protein and an increase in its inhibitor, Keap1, which mediates Nrf2 degradation in the cytosol. Moreover, a mechanism involving activation of the nuclear Nrf2 export/degradation machinery via Gsk3β-signaling was found in the KO heart. This is evident by: (i) increased Gsk3β activation; (ii) increased Fyn-mediated nuclear Nrf2 export; and (iii) increased expression of β-TrCP that is involved in Nrf2 degradation. Furthermore, a corresponding decrease in Nrf2-DNA-binding activity and a general decrease in Nrf2-target mRNA was observed in KO heart. Collectively, despite marked mitochondrial iron accumulation in FA cardiomyopathy, Nrf2 activity was disrupt via two mechanisms: increased Keap1 that decreases cytosolic Nrf2, and the activation of Gsk3β-signaling that decreases nuclear Nrf2.

Higher peptide nonplanarity (ω) close to protein carboxy-terminal and its positive correlation with ψ dihedral-angle is evolved conferring protein thermostability

BackgroundThermostability conferred by ensembles of several weak-interactions results in compactness-rigidity in proteins that impairs their flexibility/function. Understanding of protein's structural modification under stress is important. MethodIn this study, randomly selected 54 nonhomologous and variedly thermostable (0–20 °C/21–40 °C/41–60 °C/61–80 °C/81–100 °C) proteins were investigated to elucidate their thermostability utilizing multiple bioinformatics-tools. Important physico-chemical factors/peptide-nonplanarity(ω) and Ramachandran-plot were analyzed from the proteins’ PDB-structure by SPSS-programme. ResultOur ANOVA results suggest that temperature exerted significant and periodic influences on ω (F = 5.81/p = 0.0001) and ψ (F = 6.52/p = 0.0001) dihedral-angles in proteins where peptide nonplanarity obviously favored thermostability. The Pearson-correlation and further goodness of-fit model from ordinal-regression analysis suggest that nonplanarity is increasingly abundant in protein carboxy-terminal (χ2 = 37.9/p = 0.0001) at higher temperatures. Moreover, the ω is found to be highly correlated with ψ (r = 0.289/p = 0.0001) but not ɸ (r = −0.071/p = 0.365) which is supported by the regression-analysis (R2 = 0.085/F = 7.623/p < 0.001). Consistent and paradoxical decrease in the protein-size is linked to protein-thermostability. Hydrophobicity/hydrophilicity/protein phosphorylation and iso-electric point/charge were found to be grossly increasing with the protein-thermostability. However, outlier/disallowed residue-number (mean ± SD) was lower in moderate- and hyper-thermostable proteins, indicating temperature as a better purifying naturalselection-pressure to generate consistent allelic-fitness. ConclusionsIn the current study, irrespective to the protein homology, nonplanarity has been demonstrated as a significant determinant of protein-thermostability

PO-307 Paradoxical decrease in H2AFX copy number yet increasing mRNA expression in human breast cancer

IntroductionHistones are basic proteins responsible for DNA packaging in eukaryotic cell nuclei. H2AX is an H2A variant that plays an important role early in the DNA damage response. Although H2AX expression has been investigated, the direct contribution of this abundant chromatin protein in breast cancer is not well understood. The H2AFX gene encodes the same H2AX protein by both a short non-polyadenylated transcript and a longer polyadenylated transcript. We are characterising H2AFX copy number (CN), mRNA expression and protein abundance in breast cancer to discover if this foundation chromatin component contributing to genome stability could play a role in breast cancer.Material and methodsH2AFX mRNA abundance was analysed in a panel of breast cell lines by absolute quantitative PCR. The Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) dataset was used for bioinformatic analysis.Results and discussionsAnalysis of the METABRIC dataset shows that H2AFX copy number alterations involving loss of one allele are very common (41%) and correlate with genome instability. No diploid deletions are observed, and only 2% of samples show H2AFX CN amplifications. No mutations were observed in the H2AFX coding region. Although we observed that the H2AFX short transcript is more abundant than the long transcript in the panel of breast cell lines, we found that the ratio of short and long transcript is constant. This validates the relevance of transcriptomic databases using polyA-selected H2AFX mRNAs that only report long transcript abundance. Analysis of H2AFX mRNA levels in METABRIC revealed an increase in H2AFX expression with worsening prognosis, despite the decrease in gene dosage. Furthermore, we found that H2AFX copy number decreases while H2AFX mRNA expression increases during the progression from luminal A to luminal B which are the most common breast cancer subtypes.ConclusionAnalysis of primary breast tumour genomic datasets revealed that H2AFX frequently has reduced copy number but is almost never fully deleted, mutated, or amplified. One copy is lost usually as a result of a major deletion in the 11q chromosome arm. Paradoxically, H2AFX expression is frequently increased suggesting that an independent mechanism for regulation exists to drive up-regulation. We are now bringing together H2AFX copy number, mRNA expression and protein data to understand whether H2AFX expression responds to challenges to genome integrity in breast cancer.

The Effects of Immune Modulators on Amodiaquine-Induced Liver Injury.

If idiosyncratic drug-induced liver injury (IDILI) is immune mediated, then it is logical that immune modulators may be able to affect liver injury caused by a drug. We have previously shown that modulating the immune system by impairing programmed cell death protein (PD-1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) signaling, both receptors involved in immune tolerance, was capable of producing an animal model of amodiaquine (AQ) IDILI with characteristics very similar to IDILI in humans. Other immune modulators may also increase liver injury caused by drugs that cause IDILI in humans. In this study, myeloid derived suppressor cells (MDSCs), transforming growth factor beta (TGF-β), and lymphocyte-activation gene 3 (LAG3) were targeted with antibodies, with and without PD-1 and CTLA-4 impairment. We found that anti-Gr1 antibodies used to deplete MDSCs led to a significant increase in AQ-induced liver injury in wild-type mice; however, the injury was actually less in PD-1-/- mice, with or without anti-CTLA-4, and it was less than we have previously observed in PD-1-/- mice combined with anti-CTLA-4 without anti-Gr1. Addition of anti-LAG3 or anti-TGF-β antibodies produced a small increase ALT in AQ-treated wild-type mice. There was a significant increase in ALT in PD-1-/- mice co-treated with anti-LAG3 or anti-TGF-β relative to AQ-treated wild-type mice. In the case of TGF-β, this was further increased by the addition of anti-CTLA-4, but if anything, there appeared to be a paradoxical decrease when anti-CTLA-4 was combined with anti-LAG3. Overall, the results from this study were not always as expected, and they highlight the complexity of the immune response, in particular immune tolerance, which appears to be the dominant immune response to drugs that cause IDILI.

Acute and chronic resistance training downregulates select LINE-1 retrotransposon activity markers in human skeletal muscle.

Herein, we examined if acute or chronic resistance exercise affected markers of skeletal muscle long interspersed nuclear element-1 (LINE-1) retrotransposon activity. In study 1, 10 resistance-trained college-aged men performed three consecutive daily back squat sessions, and vastus lateralis biopsies were taken before (Pre), 2 h following session 1 (Post1), and 3 days following session 3 (Post2). In study 2, 13 untrained college-aged men performed a full-body resistance training program (3 days/wk), and vastus lateralis biopsies were taken before ( week 0) and ~72 h following training cessation ( week 12). In study 1, LINE-1 mRNA decreased 42-48% at Post1 and 2 ( P < 0.05), and reverse transcriptase (RT) activity trended downward at Post2 (-37%, P = 0.067). In study 2, LINE-1 mRNA trended downward at week 12 (-17%, P = 0.056) while LINE-1 promoter methylation increased (+142%, P = 0.041). Open reading frame (ORF)2p protein expression (-24%, P = 0.059) and RT activity (-26%, P = 0.063) also trended downward by week 12. Additionally, changes in RT activity versus satellite cell number were inversely associated ( r = -0.725, P = 0.008). Follow-up in vitro experiments demonstrated that 48-h treatments with lower doses (1 μM and 10 μM) of efavirenz and nevirapine (non-nucleoside RT inhibitors) increased myoblast proliferation ( P < 0.05). However, we observed a paradoxical decrease in myoblast proliferation with higher doses (50 μM) of efavirenz and delavirdine. This is the first report suggesting that resistance exercise downregulates markers of skeletal muscle LINE-1 activity. Given our discordant in vitro findings, future research is needed to thoroughly assess whether LINE-1-mediated RT activity enhances or blunts myoblast, or primary satellite cell, proliferative capacity.

ДІАГНОСТИЧНЕ ЗНАЧЕННЯ ЛАБОРАТОРНИХ ПОКАЗНИКІВ ЕНДОГЕННОЇ ІНТОКСИКАЦІЇ ПРИ НЕГОСПІТАЛЬНІЙ ПНЕВМОНІЇ

Вступ. Синдром ендогенної інтоксикації (EI) на сьогодні залишається провідним у клінічній картині негоспітальної пневмонії (НП), його вираженість співвідноситься з тяжкістю захворювання. Зміна клінічної картини пневмонії, висока частота виникнення її атипових форм, значний рівень смертності зумовлюють необхідність виявлення чітких критеріїв оцінки тяжкості патологічного процесу. В якості таких критеріїв можуть бути використані лабораторні маркери ЕІ, але вивчення їх діагностичного значення триває.Метою дослідження стало визначення змін лабораторних показників ЕІ у хворих на НП залежно від тяжкості захворювання.Матеріал і методи. Обстежено 175 хворих на НП, яких поділили на 3 групи за тяжкістю перебігу захворювання згідно зі шкалою Pneumonia PORT. У розпал захворювання визначали наступні маркери ЕІ: молекули середньої маси сироватки крові фракцій MСM254 та MСM280, лейкоцитарний індекс інтоксикації, токсичність сироватки крові та інтерстиціальної рідини за сім’яним тестом.Результати. У групах пацієнтів з НП II і III класів за шкалою Pneumonia PORT було встановлено, що розвиток запалення в легенях супроводжується токсемією: значення досліджуваних параметрів у групах обстежуваних зростали пропорційно до тяжкості захворювання. Тяжкий перебіг пневмонії (IV клас) супроводжувався значним накопиченням токсинів в інтерстиції, помітним підвищенням МСМ280, а у деяких пацієнтів – парадоксальним зниженням лейкоцитарного індексу інтоксикації. Ці дані вказують на перенапруження систем детоксикації, які характерні для ендотоксикозу.Висновок. Лабораторні маркери ендогенної інтоксикації можуть бути використані як критерії тяжкості негоспітальної пневмонії, але їх дослідження має бути комплексним, щоб характеризувати як токсемію, так і ендотоксикоз.

Pro-arrhythmic atrial phenotypes in incrementally paced murine Pgc1β-/- hearts: effects of age.

New Findings What is the central question of this study? Can we experimentally replicate atrial pro‐arrhythmic phenotypes associated with important chronic clinical conditions, including physical inactivity, obesity, diabetes mellitus and metabolic syndrome, compromising mitochondrial function, and clarify their electrophysiological basis? What is the main finding and its importance? Electrocardiographic and intracellular cardiomyocyte recording at progressively incremented pacing rates demonstrated age‐dependent atrial arrhythmic phenotypes in Langendorff‐perfused murine Pgc1β −/− hearts for the first time. We attributed these to compromised action potential conduction and excitation wavefronts, whilst excluding alterations in recovery properties or temporal electrophysiological instabilities, clarifying these pro‐arrhythmic changes in chronic metabolic disease. Atrial arrhythmias, most commonly manifesting as atrial fibrillation, represent a major clinical problem. The incidence of atrial fibrillation increases with both age and conditions associated with energetic dysfunction. Atrial arrhythmic phenotypes were compared in young (12–16 week) and aged (>52 week) wild‐type (WT) and peroxisome proliferative activated receptor, gamma, coactivator 1 beta (Ppargc1b)‐deficient (Pgc1β −/−) Langendorff‐perfused hearts, previously used to model mitochondrial energetic disorder. Electrophysiological explorations were performed using simultaneous whole‐heart ECG and intracellular atrial action potential (AP) recordings. Two stimulation protocols were used: an S1S2 protocol, which imposed extrasystolic stimuli at successively decremented intervals following regular pulse trains; and a regular pacing protocol at successively incremented frequencies. Aged Pgc1β −/− hearts showed greater atrial arrhythmogenicity, presenting as atrial tachycardia and ectopic activity. Maximal rates of AP depolarization (dV/dt max) were reduced in Pgc1β −/− hearts. Action potential latencies were increased by the Pgc1β −/− genotype, with an added interactive effect of age. In contrast, AP durations to 90% recovery (APD90) were shorter in Pgc1β −/− hearts despite similar atrial effective recovery periods amongst the different groups. These findings accompanied paradoxical decreases in the incidence and duration of alternans in the aged and Pgc1β −/− hearts. Limiting slopes of restitution curves of APD90 against diastolic interval were correspondingly reduced interactively by Pgc1β −/− genotype and age. In contrast, reduced AP wavelengths were associated with Pgc1β −/− genotype, both independently and interacting with age, through the basic cycle lengths explored, with the aged Pgc1β −/− hearts showing the shortest wavelengths. These findings thus implicate AP wavelength in possible mechanisms for the atrial arrhythmic changes reported here.

"Paradoxical" findings of tumor vascularity and oxygenation in recurrent glioblastomas refractory to bevacizumab.

Anti-angiogenic therapy induces the apparent normalization of vascular structure, decreases microvessel density (MVD), and improves tumor oxygenation in glioblastomas (GBMs). Six initial and recurrent tumor pairs after bevacizumab (Bev) treatment were compared with GBMs from nine patients resected under neoadjuvant Bev treatment with regard to histological characteristics; MVD; MIB-1 index; and expression of vascular endothelial growth factor (VEGF) and its receptors, hypoxia markers (hypoxia-inducible factor 1 alpha, carbonic anhydrase 9), and nestin as a marker of glioma stem-like cells. In recurrent tumors post-Bev treatment, while the MVD remained low compared with the paired initial tumors (pre-Bev tumors), the expression of hypoxic markers were increased and were even higher in expression compared with the paired pre-Bev tumors in three of the six cases. MIB-1 indices were similar among the initial GBMs, neoadjuvant group, and recurrent tumors post-Bev treatment. The nestin-positive cell ratio of the post-Bev recurrent tumors was as high as that of the pre-Bev tumors. The expression of VEGF and VEGFR1 was increased in the post-Bev recurrent tumors in three and four cases, respectively, compared with the paired pre-Bev tumors. In the majority of Bev-refractory GBMs, tumor hypoxia was present with a paradoxical decrease in MVD. These findings suggest that re-activation of tumor angiogenesis is not initially involved in the acquisition of resistance to Bev.

NFκB signaling in alveolar rhabdomyosarcoma.

ABSTRACTAlveolar rhabdomyosarcoma (aRMS) is a pediatric soft tissue cancer commonly associated with a chromosomal translocation that leads to the expression of a Pax3:Foxo1 or Pax7:Foxo1 fusion protein, the developmental underpinnings of which may give clues to its therapeutic approaches. In aRMS, the NFκB–YY1–miR-29 regulatory circuit is dysregulated, resulting in repression of miR-29 and loss of the associated tumor suppressor activity. To further elucidate the role of NFκB in aRMS, we first tested 55 unique sarcoma cell lines and primary cell cultures in a large-scale chemical screen targeting diverse molecular pathways. We found that pharmacological inhibition of NFκB activity resulted in decreased cell proliferation of many of the aRMS tumor cultures. Surprisingly, mice that were orthotopically allografted with aRMS tumor cells exhibited no difference in tumor growth when administered an NFκB inhibitor, compared to control. Furthermore, inhibition of NFκB by genetically ablating its activating kinase inhibitor, IKKβ, by conditional deletion in a mouse model harboring the Pax3:Foxo1 chimeric oncogene failed to abrogate spontaneous tumor growth. Genetically engineered mice with conditionally deleted IKKβ exhibited a paradoxical decrease in tumor latency compared with those with active NFκB. However, using a synthetic-lethal approach, primary cell cultures derived from tumors with inactivated NFκB showed sensitivity to the BCL-2 inhibitor navitoclax. When used in combination with an NFκB inhibitor, navitoclax was synergistic in decreasing the growth of both human and IKKβ wild-type mouse aRMS cells, indicating that inactivation of NFκB alone may not be sufficient for reducing tumor growth, but, when combined with another targeted therapeutic, may be clinically beneficial.

Key role of segment IS4 in Cav1.2 inactivation: link between activation and inactivation

Inactivation of L-type calcium channel (Cav1.2) is an important determinant of the length of the cardiac action potential. Here, we report a key role of the voltage-sensing segment IS4 in Cav1.2 inactivation. Neutralization of IS4 charges gradually shifted the steady-state inactivation curve on the voltages axis from 5.1 ± 3.7 mV in single point mutant IS4(K1Q) to −26.7 ± 1.3 mV in quadruple mutant IS4(K1Q/R2Q/R3Q/R4Q) compared to wild-type (WT) and accelerated inactivation. The slope factor of the Boltzmann curve of inactivation was decreased from 17.4 ± 3.5 mV (IS4(K1Q)) to 6.2 ± 0.7 mV (IS4(K1Q/R2Q/R3Q/R4Q)). Neutralizations of single or multiple charges in IIS4 and IIIS4 did not significantly affect the time course of inactivation. Neutralization of individual IVS4 charges shifted the inactivation curve between 17.4 ± 1.7 mV (IVS4(R2Q)) and −4.6 ± 1.4 mV (IVS4(R4Q)) on the voltage axis and affected the slope of the inactivation curves (IVS4(R2Q): 10.2 ± 1.2 mV, IVS4(R4Q): 9.7 ± 0.7 mV and IVS4(K5Q): 8.1 ± 0.7 mV vs WT: 14.1 ± 0.8 mV). IS4(K1Q) attenuated while IS4(K1Q/R2Q/R3Q) and IS4(K1Q/R2Q/R4Q/R3Q) enhanced the development of inactivation. Shifts in the voltage dependence of inactivation curves induced by IS4 neutralizations significantly correlated with shifts of the voltage dependence of channel activation (r = 0.95, p < 0.01) indicating that IS4 movement is not only rate limiting for activation but also initiates inactivation. The paradoxical decrease of the slope factor of the steady-state inactivation and acceleration of inactivation kinetics upon charge neutralization in segment IS4 may reflect the loss of stabilizing interactions of arginines and lysine with surrounding residues.

Enhancing KCC2 function counteracts morphine-induced hyperalgesia

Morphine-induced hyperalgesia (MIH) is a severe adverse effect accompanying repeated morphine treatment, causing a paradoxical decrease in nociceptive threshold. Previous reports associated MIH with a decreased expression of the Cl− extruder KCC2 in the superficial dorsal horn (SDH) of the spinal cord, weakening spinal GABAA/glycine-mediated postsynaptic inhibition. Here, we tested whether the administration of small molecules enhancing KCC2, CLP257 and its pro-drug CLP290, may counteract MIH. MIH was typically expressed within 6–8 days of morphine treatment. Morphine-treated rats exhibited decreased withdrawal threshold to mechanical stimulation and increased vocalizing behavior to subcutaneous injections. Chloride extrusion was impaired in SDH neurons measured as a depolarizing shift in EGABA under Cl− load. Delivering CLP257 to spinal cord slices obtained from morphine-treated rats was sufficient to restore Cl− extrusion capacity in SDH neurons. In vivo co-treatment with morphine and oral CLP290 prevented membrane KCC2 downregulation in SDH neurons. Concurrently, co-treatment with CLP290 significantly mitigated MIH and acute administration of CLP257 in established MIH restored normal nociceptive behavior. Our data indicate that enhancing KCC2 activity is a viable therapeutic approach for counteracting MIH. Chloride extrusion enhancers may represent an effective co-adjuvant therapy to improve morphine analgesia by preventing and reversing MIH.

Structural and electronic modifications of pyridones and pyrones via regioselective bromination and trifluoromethylation

We report regioselective functionalization of pyridones and pyrones via electrophilic bromination (Br2) or radical trifluoromethylation (NaSO2CF3/tBuOOH) at the 3-position. Counter-intuitively, the 3-position EW groups decreased the carbonyl stretching energy by 6–23 cm−1; however, 3,5-dibromination increased the CO frequency by 10–22 cm−1 compared to the 3-Br pyridones. X-ray crystallography revealed pyridone tautomers with contracted CO bond metrics. pKa values and 1H NMR shifts for the series 3-H→Br→CF3 revealed the expected trend of increasing acidity (pKa = 8.85 → 8.33→6.78, MeOH) and increasing chemical shifts (10.97 → 11.42→11.71 DMSO-d6). We conclude that the paradoxical decrease in CO stretching frequencies by the 3-positoin EW groups is explained by an ‘assistive’ electron-withdrawing effect, whereby the 3-position EW group assists the electronegative oxygen atom in recruiting more electron density, and – as a result – attaining more oxyanion character (decreased the CO bond strength).

Characteristics of the expression of the transcription factor pSTAT3 in asthma

To investigate the transcription factor pSTAT3 in overweight asthmatics on a model of peripheral blood mononuclear cells at baseline and during recombinant leptin modulation. A flow fluorometric assay was used according to the standard Bio-Plex protocol on a Bio-Plex immunoanalyzer (a flow fluorimeter) (Bio-Rad, USA) using xMAP technology at baseline and during modulation with recombinant leptin (Leptin, human, recombinant, expressed in a E. coli, Sigma, USA). There was an obvious reduction in the level of the transcription factor pSTAT3 in patients with non-allergic asthma and an increase in that in patients with allergic asthma (AA). Recombinant leptin modulation of pSTAT3 levels caused their paradoxical decrease in both overweight women younger than 45 years of age with AA and in those with non-allergic asthma. The elevated level of the transcription factor pSTAT3 in AA is probably due to the overexpression of pSTAT3 in this group of patients. The paradoxical decrease in pSTAT3 levels in overweight women under 45 years of age with AA, which is similar in the non-allergic asthma group, can be explained by the enhanced expression of negative SOCS3 regulators and by leptin resistance.

Properties of pattern standard deviation in open-angle glaucoma patients with hemi-optic neuropathy and bi-optic neuropathy.

PurposeTo evaluate the properties of pattern standard deviation (PSD) according to localization of the glaucomatous optic neuropathy.MethodsWe enrolled 242 eyes of 242 patients with primary open-angle glaucoma, with a best-corrected visual acuity ≥ 20/25, and no media opacity. Patients were examined via dilated fundus photography, spectral-domain optical coherence tomography, and Humphrey visual field examination, and divided into those with hemi-optic neuropathy (superior or inferior) and bi-optic neuropathy (both superior and inferior). We assessed the relationship between mean deviation (MD) and PSD. Using broken stick regression analysis, the tipping point was identified, i.e., the point at which MD became significantly associated with a paradoxical reversal of PSD.ResultsIn 91 patients with hemi-optic neuropathy, PSD showed a strong correlation with MD (r = −0.973, β = −0.965, p < 0.001). The difference between MD and PSD (“−MD−PSD”) was constant (mean, −0.32 dB; 95% confidence interval, −2.48~1.84 dB) regardless of visual field defect severity. However, in 151 patients with bi-optic neuropathy, a negative correlation was evident between “−MD−PSD” and MD (r2 = 0.907, p < 0.001). Overall, the MD tipping point was −14.0 dB, which was close to approximately 50% damage of the entire visual field (p < 0.001).ConclusionsAlthough a false decrease of PSD usually begins at approximately 50% visual field damage, in patients with hemi-optic neuropathy, the PSD shows no paradoxical decrease and shows a linear correlation with MD.

Molecular Bases Determining Daptomycin Resistance-Mediated Resensitization to β-Lactams (Seesaw Effect) in Methicillin-Resistant Staphylococcus aureus.

Antimicrobial resistance is recognized as one of the principal threats to public health worldwide, yet the problem is increasing. Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) strains are among the most difficult to treat in clinical settings due to the resistance of MRSA to nearly all available antibiotics. The cyclic anionic lipopeptide antibiotic daptomycin (DAP) is the clinical mainstay of anti-MRSA therapy. The decreased susceptibility to DAP (DAP resistance [DAPr]) reported in MRSA is frequently accompanied by a paradoxical decrease in β-lactam resistance, a process known as the "seesaw effect." Despite the observed discordance in resistance phenotypes, the combination of DAP and β-lactams has been proven to be clinically effective for the prevention and treatment of infections due to DAPr MRSA strains. However, the mechanisms underlying the interactions between DAP and β-lactams are largely unknown. In the study described here, we studied the role of mprF with DAP-induced mutations in β-lactam sensitization and its involvement in the effective killing by the DAP-oxacillin (OXA) combination. DAP-OXA-mediated effects resulted in cell wall perturbations, including changes in peptidoglycan insertion, penicillin-binding protein 2 (PBP 2) delocalization, and reduced membrane amounts of PBP 2a, despite the increased transcription of mecA through mec regulatory elements. We have found that the VraSR sensor-regulator is a key component of DAP resistance, triggering mutated mprF-mediated cell membrane (CM) modifications that result in impairment of PrsA location and chaperone functions, both of which are essential for PBP 2a maturation, the key determinant of β-lactam resistance. These observations provide for the first time evidence that synergistic effects between DAP and β-lactams involve PrsA posttranscriptional regulation of CM-associated PBP 2a.

Impact of Paradoxical Decrease in High-density Lipoprotein Cholesterol Levels After Statin Therapy on Major Adverse Cardiovascular Events in Patients with Stable Angina Pectoris

PurposeStatin therapy usually increases HDL-C levels. However, a paradoxical decrease in HDL-C levels after statin therapy is often seen in clinical settings. The relationship between a paradoxical decrease in HDL-C levels after statin therapy and adverse cardiovascular events in patients with stable angina pectoris (SAP) is not well understood. The purpose of this study was to analyze the relationship between paradoxical HDL-C decreases after statin therapy and major adverse cardiovascular events (MACEs) in patients undergoing percutaneous coronary intervention (PCI) for SAP. MethodsBetween January 2006 and March 2015, 867 patients underwent PCI for SAP. Of them, we enrolled 209 patients who were newly started on statin therapy before PCI. We excluded patients who had started statin therapy earlier than 6 months before PCI, patients who had not started statin therapy after PCI, and patients who were diagnosed with acute coronary syndrome. They were divided into 2 groups according to the change in their HDL-C levels between baseline and 6 to 9 months after the index PCI: decreased HDL group after statin treatment (80 patients) and increased HDL group (129 patients). The primary end points were MACEs defined as a composite of all-cause death, nonfatal acute myocardial infarction, and target vessel revascularization (TVR). FindingsUsing Kaplan-Meier analysis, the 7-year event rate for composite MACEs in the decreased HDL group was found to be higher than that for the increased HDL group (38% versus 24%, log-rank P = 0.02). TVR occurred more frequently in the decreased HDL group than in the increased HDL group (32% versus 12%, log-rank P = 0.01). With the use of multivariate analysis, changes in HDL-C levels after statin therapy indicated a significant inverse association with the increased risk of MACEs, (hazard ratio [HR] = 0.94; 95% CI, 0.92–0.97; P < 0.01). The incidence of MACEs was more strongly associated with ΔHDL than with ΔLDL. Moreover, BMS usage also independently predicted MACEs (HR = 2.18; 95% CI, 1.14–4.17; P < 0.01). ImplicationsA paradoxical decrease in HDL-C levels after statin therapy might be a risk factor for MACEs, especially TVR, in patients with SAP.

Pre-Load–Induced Changes in Forward LV Stroke and Functional Mitral Regurgitation: Echocardiographic Detection of the Descending Limb of Starling's Curve

ObjectivesThe purpose of this study was to clarify the prognostic significance of diagnosing whether the failing heart is functioning on the descending limb of the Starling curve by using echocardiography with passive leg lifting (PLL). BackgroundPatients with advanced heart failure can shift to the descending limb of the Starling curve, in which pre-load does not lead to an expected increase in forward left ventricular stroke volume (LVSV). MethodsThirty-five consecutive patients with left ventricular (LV) ejection fraction of <40% underwent echocardiography at rest during baseline and during PLL to increase pre-load. ResultsDespite PLL, a paradoxical decrease in forward LVSV was observed in 15 (43%) patients. Changes in forward LVSV inversely correlated with those in functional mitral regurgitation (r = −0.56). The primary endpoint of cardiac death or hospitalization due to worsening heart failure occurred in 15 (43%) patients during follow-up (2.8 ± 2.2 years). There were a number of significant predictors of the primary endpoint in the univariate Cox analysis: baseline E/A ratio (p = 0.0002), paradoxical decrease in LVSV despite PLL (hazard ratio: 4.44; 95% confidence interval: 1.41 to 14.0; p = 0.011), baseline LV end-systolic volume (p = 0.023), and baseline LV ejection fraction (p = 0.034). In the bivariate Cox analysis, an addition of the paradoxical decrease in LVSV significantly enhanced the predictive power of all other univariate predictors. ConclusionsHeart failure patients with LV systolic dysfunction on the descending limb of the Starling curve can be recognized by the paradoxical decrease in LVSV despite PLL, and the prognostic predicting power is additive to the other traditional echocardiographic predictors. Also, our results suggest that functional mitral regurgitation is an important reason for the descending limb of the Starling curve, which is clinically recognized as the pre-load–induced decrease in forward LVSV.

Does treatment of paradoxical vocal fold movement disorder decrease asthma medication use?

To determine whether diagnosis and treatment of paradoxical vocal fold movement disorder (PVFMD) leads to decreased asthma medication use. Secondary objectives include determining initial rate of asthma medication use, characterizing symptom improvement, and correlating with pulmonary function testing (PFT). Prospective observational study. Patients newly diagnosed with PVFMD at a single institution were recruited to participate. Medication questionnaires were completed at the initial visit, at the first return visit for therapy, and at 6 months. PFTs were reviewed when available. Sixty-six patients were recruited; the study was closed early because findings reached significance. Fifty-six patients (85%) were taking asthma medication at presentation. Forty-four patients presented with PFTs, and two-thirds were normal. Forty-two patients completed follow-up questionnaires; 79% decreased asthma medication use (P < .001), and 82% reported symptom improvement. Seventy-seven percent of patients participated in therapy and 23% did not, with equal rates of decrease in asthma medication use between these groups. Outcomes did not vary based on PFT pattern (i.e., obstructive vs. nonobstructive, P = .75). Diagnosis and treatment of PVFMD lead to a decline in asthma medication use. This decrease occurred alongside symptom improvement and irrespective of PFT findings. Use of asthma medication in this patient population is high, at 85%. 4. Laryngoscope, 127:1531-1537, 2017.