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Background: Pulmonary hypertension (PH) frequently complicates the evaluation of kidney transplantation (KT) candidates, and is associated with increased adverse outcomes [mortality, delayed graft function (DGF), and major adverse cardiovascular event] following KT., Research Question: What is the relationship between cardiopulmonary hemodynamics and post-KT outcomes?, Study Design and Methods: We conducted a multicenter retrospective cohort study of adults undergoing KT between October 1, 2011 and October 1, 2021, who underwent right heart catheterization (RHC) to assess cardiopulmonary hemodynamics within 1 year of transplantation. Frailty models and logistic regression models were used to evaluate the association between cardiopulmonary hemodynamics and outcomes (mortality, DGF, major adverse cardiovascular event) following KT., Results: A total of 117 patients were included in the final analysis, predominantly male (72%), with a median age of 57 years. PH, defined as mean pulmonary artery pressure (mPAP) > 20 mm Hg, was present in most of the cohort (n = 93; 79%). The cohort was monitored for a median of 29.9 months post-KT, during which about one-fourth experienced mortality (23%) or DGF (25%) events, and approximately one-third (34%) experienced major adverse cardiovascular event. Although echocardiographic measures of pulmonary artery pressure failed to identify post-KT outcomes, a mPAP of ≥ 30 mm Hg on RHC was associated with post-KT major adverse cardiovascular event (hazard ratio, 2.60; 95% CI, 1.10-6.10) and more prevalent in those experiencing post-KT mortality (63% vs 32%; P = .001). Precapillary pulmonary hypertension was also associated with post-KT mortality (hazard ratio, 3.71; 95% CI, 1.07-12.90)., Interpretation: Precapillary pulmonary hypertension and an mPAP of ≥ 30 mm Hg on RHC, but not echocardiographic evidence of PH, was associated with mortality and major adverse cardiovascular event following KT. These data suggest that RHC hemodynamics are superior to echocardiographic measures of PH in association with outcomes following KT, and RHC-derived mPAP in particular may have value in predicting major adverse cardiovascular event and mortality post-KT., Competing Interests: Financial/Nonfinancial Disclosures The authors have reported to CHEST the following: A. J. reports investigator-initiated research supported by United Therapeutics. S. S. K. has received research grant support from Edwards Life Sciences, Hemosonics, and PCORI. R. G. A. has received research grant support and served on the consultant or advisory board of United Therapeutics. N. M. B. is the site principal investigator for a clinical trial sponsored by Rednvia. J. M. E. has received research grant support from Janssen, United Therapeutics, Liquidia, Phase Bio, Gossamer Bio, Bayer, Merck, Altavant, Aerovate, Tenax, and Pharmosa, and serves on the consultant or advisory board of United Therapeutics, Altavant, Aerovate, Bayer, Gossamer Bio, Liquidia, Merck, and Janssen. None declared (L. G., S. H. F., A. S. F., D. S., M. V., N. J. D., A. P., C. J.)., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Competing Interests: Declaration of Competing Interest None.

Objectives: HIV-associated dementia (HAD) is the most severe clinical expression of HIV-mediated neuropathology, and the processes underlying its development remain poorly understood. We aimed to exploit high-dimensional metabolic profiling to gain insights into the pathological mechanisms associated to HAD., Design: In this cross-sectional study, we utilized metabolomics to profile matched cerebrospinal fluid (CSF) and plasma samples of HAD individuals ( n  = 20) compared with neurologically asymptomatic people with HIV (ASYM, n  = 20) and healthy controls (NEG, n  = 20)., Methods: Identification of plasma and CSF metabolites was performed by liquid-chromatography or gas-chromatography following a validated experimental pipeline. The resulting metabolic profiles were analyzed by machine-learning algorithms, and altered pathways were identified by comparison with KEGG pathway database., Results: In CSF, HAD patients displayed an imbalance in glutamine/glutamate ratio, decreased levels of isocitrate and arginine, and increased oxidative stress when compared with ASYM or NEG. These changes were confirmed in matched plasma samples, which in addition revealed an accumulation of eicosanoids and unsaturated fatty acids in HAD individuals. Pathway analysis in both biological fluids suggested that alterations in several metabolic processes, including protein biosynthesis, glutamate and arginine metabolism, and energy metabolism, in association to a perturbed eicosanoid metabolism in plasma, may represent the metabolic signature associated to HAD., Conclusion: These findings show that HAD may be associated with metabolic modifications in CSF and plasma. These preliminary data may be useful to identify novel metabolic biomarkers and therapeutic targets in HIV-associated neurological impairment., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Liver transplantation is associated with significant blood loss, often requiring massive blood product transfusion. Transfusion-related acute lung injury (TRALI) is a devastating cause of transfusion-related deaths. While reports have investigated the general incidence of TRALI, the incidence of TRALI specifically following transfusion during liver transplant remains unclear. This scoping review summarizes existing literature regarding TRALI during the liver transplantation perioperative period. Databases were searched for all articles and abstracts reporting on TRALI after liver transplantation. Data collected included number of patients studied, patient characteristics, incidences of TRALI, TRALI characteristics, and patient outcomes. The primary outcome investigated was the incidence of TRALI in the setting of liver transplantation. Thirteen full-text citations were included in this review. The incidence of TRALI post-liver transplant was 0.68% (65 of 9,554). Based on reported transfusion data, patients diagnosed with TRALI received an average of 10.92 ± 10.81 units of packed red blood cells (pRBC), 20.05 ± 15.72 units of fresh frozen plasma, and 5.75 ± 10.00 units of platelets. Common interventions following TRALI diagnosis included mechanical ventilation with positive end-expiratory pressure, inhaled high-flow oxygen, inhaled pulmonary vasodilator, and pharmacologic treatment using pressors or inotropes, corticosteroids, or diuretics. Based on reported mortality data, 26.67% of patients (12 of 45) diagnosed with TRALI died during the postoperative period. This scoping review underscores the importance of better understanding the incidence and presentation of TRALI after liver transplant surgery. The clinical implications of these results warrant the development of identification and management strategies for liver transplant patients at increased risk for developing TRALI., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: New or worsened mitral regurgitation (MR) is an uncommon yet serious complication after surgical aortic valve replacement (SAVR). While there have been numerous reports of its occurrence, there is little consensus regarding its presentation and management. This systematic review summarizes the evidence in the current literature surrounding new or worsened MR after SAVR and analyzes its potential implications., Methods: Databases were examined for all articles and abstracts reporting on new or worsened MR after SAVR. Data collected included number of patients studied; patient characteristics; incidences of new or worsened MR; timing of diagnosis; and treatment., Results: Thirty-six full-text citations were included in this review. The prevalence of new or worsened MR after SAVR was 8.4%. Sixteen percent of new MR occurrences were from an organic etiology, and 83% of new MR occurrences were that of a functional etiology. Most diagnoses were made in the late or unspecified postoperative period using echocardiography (range: 0 minutes to 18 years postoperatively). While no patients died from this complication, 7.7% of patients (16 out of 207) required emergent procedural re-intervention., Conclusions: This systematic review underscores the importance of identifying new or worsened MR following SAVR and accurate scoring of MR severity to guide treatment. It also outlines the associated clinical measures commonly documented following this complication, and the usefulness of transesophageal echocardiography for the detection of significant MR. These results reflect the current, limited state of the literature on this topic and warrant further investigation into MR detection and management strategies in SAVR patients.

Background: Pulmonary artery obstruction is an uncommon but significant complication after lung transplantation. Although numerous reports have documented its occurrence, the hemodynamic parameters associated with its presentation and diagnostic considerations remain ill-defined. This systematic review summarizes evidence in the literature surrounding pulmonary artery obstruction after lung transplantation surgery., Methods: Databases were searched for all articles and abstracts reporting on pulmonary artery obstruction. Data collected included the number of patients studied, patient characteristics, incidences of pulmonary artery obstruction, and timing and imaging modality used for diagnosis., Results: Thirty-four full-text citations were included in this review. The point prevalence of pulmonary artery obstruction was 3.66%. The peak pulmonary artery velocity associated with obstruction was found to be 2.60 ± 0.58 m/s. The diameter of the obstructed pulmonary artery predictive of poor outcomes was noted to be 0.78 ± 0.40 cm. The majority of diagnoses were made in the late postoperative period using pulmonary angiogram and transesophageal echocardiography. Overall, 76% of patients (47 of 62) required emergent procedural reintervention, and 23% of patients (14 of 62) diagnosed with pulmonary artery obstruction died during their hospital stay., Conclusions: This systematic review underscores the importance of identifying pulmonary artery obstruction immediately after lung transplant surgery. The clinical implications of these results warrant the development of identification and management strategies for early detection of irregularities in pulmonary artery anastomosis in lung transplant patients., Competing Interests: M.K.E. is a consultant for Boston Scientific and S4 Medical. N.A.M. is a consultant for Abbott, Medtronic, SynCardia, and Carmat. The other authors declare no conflicts of interest., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

Purpose: To assess the feasibility and safety of same-day discharge after S-ICD implantation by implementing a specific analgesia protocol and phone follow-up., Methods: Consecutive patients presenting for outpatient S-ICD implantation were enrolled between 1/1/2018 and 4/30/2019. An analgesia protocol included pre-operative acetaminophen and oxycodone, intraoperative local bupivacaine, and limited use of oxycodone-acetaminophen at discharge. The primary outcome was successful same-day discharge. Numerical Pain Rating Scale (NPRS) on postoperative day (POD) 1, 3, 14, and 30 and any unplanned health care visits during the 1-month follow-up period were assessed., Results: Out of 53 potentially eligible S-ICD patients, 49 patients (92.5%) were enrolled and successfully discharged on the same day. Mean age of these 49 patients was 47 ± 14 years. There were no acute procedural complications. Severe pain (NPRS ≥ 8) on POD 0, 1, and 3 was present in 14.3%, 14.3%, and 8.2% of patients, respectively. The total in-hospital stay was 534 ± 80 min. Four unplanned visits (8%) due to cardiac or device-related issues occurred during 1-month follow-up, including 2 patients with heart failure exacerbation, one patient with an incisional infection, and one patient with inappropriate shocks., Conclusions: With the appropriate institutional protocol including specific analgesics and phone follow-up, same-day discharge after outpatient S-ICD implantation is feasible and appears safe for most patients.. Device-related pain can be severe in the first 3 days post-implantation and can be successfully treated with limited supply of narcotic medications.

Background: The perioperative anesthesia care during subcutaneous implantable cardioverter-defibrillator (S-ICD) implantation is still evolving., Objective: To assess the feasibility and safety of S-ICD implantation with monitored anesthesia care (MAC) versus general anesthesia (GA) in a tertiary care center., Methods: This is a single-center retrospective study of patients undergoing S-ICD implantation between October 2012 and May 2019. Patients were categorized into MAC and GA group based on the mode of anesthesia. Procedural success without escalation to GA was the primary endpoint of the study, whereas intraprocedural hemodynamics, need of pharmacological support for hypotension and bradycardia, length of the procedure, stay in the post-anesthesia care unit, and postoperative pain were assessed as secondary endpoints., Results: The study comprises 287 patients with MAC in 111 and GA in 176 patients. Compared to MAC, patients in GA group were younger and had a higher body mass index. All patients had successful S-ICD implantation. Only one patient (0.9%) in the MAC group was converted to GA. Despite a similar baseline heart rate (HR) and mean arterial blood pressure (MAP) in both groups, patients with GA had significantly lower HR and MAP during the procedure and more frequently required pharmacological hemodynamic support. Length of the procedure, stay in the postanesthesia care unit, and postoperative pain was similar in both groups., Conclusion: This retrospective experience suggests that implantation of S-ICD is feasible and safe with MAC. Use of GA is associated with more frequent administration of hemodynamic drugs during S-ICD implantation., (© 2019 Wiley Periodicals, Inc.)

Background: Pulmonary cuff dysfunction, either due to pulmonary vein obstruction, pulmonary vein stenosis, or pulmonary vein thrombosis, is an uncommon, yet serious complication after lung transplantation. Although there have been numerous reports of its occurrence, there is little consensus regarding the hemodynamic parameters associated with its presentation and diagnostic considerations. This systematic review summarizes the evidence surrounding pulmonary cuff dysfunction after lung transplantation surgery and empirically analyzes its implications., Methods: Databases were examined for all articles and abstracts reporting on pulmonary cuff dysfunction. Data collected included: number of patients studied; patients' characteristics; incidences of pulmonary vein stenosis and pulmonary vein thrombosis; and timing and imaging modality utilized for diagnosis., Results: Thirty-four full-text citations were included in this review. The point prevalence of pulmonary vein stenosis and thrombosis were 1.4% and 2.5%, respectively. The peak pulmonary cuff velocity associated with dysfunction was found to be 1.59 ± 0.66 m/sec. The diameter of the dysfunctional pulmonary vein was noted to be 0.48 ± 0.20 cm. The majority of diagnoses were made in the early post-operative period using transesophageal echocardiography. Overall, 41.3% of patients (26 of 63) required emergent procedural reintervention, and 32% of patients (20 of 63) diagnosed with pulmonary cuff dysfunction died during their hospital stay., Conclusions: This systematic review underscores the importance of identifying pulmonary cuff dysfunction after lung transplant surgery, and the usefulness of transesophageal echocardiography for detection of this complication. The clinical implications of these results warrant the further development of identification and management strategies for lung transplant patients., (Copyright © 2019 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.)

The key physical processes in polymeric filters used for the blood purification include transport across the capillary wall and the interaction of blood cells with the polymer membrane surface. Theoretical modeling of membrane transport is an important tool which provides researchers with a quantification of the complex phenomena involved in dialysis. In the paper, we present a dense review of the most successful theoretical approaches to the description of transport across the polymeric membrane wall as well as the cell⁻polymer surface interaction, and refer to the corresponding experimental methods while studying these phenomena in dialyzing filters.

Natural killer (NK) cells are an emerging immunotherapy approach to acute myeloid leukemia (AML); however, the optimal approach to activate NK cells before adoptive transfer remains unclear. Human NK cells that are primed with the CTV-1 leukemia cell line lysate CNDO-109 exhibit enhanced cytotoxicity against NK cell-resistant cell lines. To translate this finding to the clinic, CNDO-109-activated NK cells (CNDO-109-NK cells) isolated from related HLA-haploidentical donors were evaluated in a phase 1 dose-escalation trial at doses of 3 × 10 5 (n = 3), 1 × 10 6 (n = 3), and 3 × 10 6 (n = 6) cells/kg in patients with AML in first complete remission (CR1) at high risk for recurrence. Before CNDO-109-NK cell administration, patients were treated with lymphodepleting fludarabine/cyclophosphamide. CNDO-109-NK cells were well tolerated, and no dose-limiting toxicities were observed at the highest tested dose. The median relapse-free survival (RFS) by dose level was 105 (3 × 10 5 ), 156 (1 × 10 6 ), and 337 (3 × 10 6 ) days. Two patients remained relapse-free in post-trial follow-up, with RFS durations exceeding 42.5 months. Donor NK cell microchimerism was detected on day 7 in 10 of 12 patients, with 3 patients having evidence of donor cells on day 14 or later. This trial establishes that CNDO-109-NK cells generated from related HLA haploidentical donors, cryopreserved, and then safely administered to AML patients with transient persistence without exogenous cytokine support. Three durable complete remissions of 32.6 to 47.6+ months were observed, suggesting additional clinical investigation of CNDO-109-NK cells for patients with myeloid malignancies, alone or in combination with additional immunotherapy strategies, is warranted., (Copyright © 2018 The American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Importance: Although seroepidemiological studies indicate that greater than 50% of the population has been infected with John Cunningham virus (JCV), the sites of JCV persistence remain incompletely characterized., Objective: To determine sites of JCV persistence in immunologically healthy individuals., Design, Setting, and Participants: Tissue specimens from multiple sites including brain, renal, and nonrenal tissues were obtained at autopsy performed in the Department of Pathology at the University of Kentucky from 12 immunologically healthy patients between February 9, 2011, and November 27, 2012. Quantitative polymerase chain reaction was performed on the tissue specimens and urine. Serum JCV antibody status was determined by enzyme-linked immunosorbent assay., Main Outcomes and Measures: The detection and quantification of JCV from the tissues by quantitative polymerase chain reaction illuminated sites of viral persistence. These results were correlated with JCV antibody levels., Results: Autopsies were performed on 12 individuals, 10 men and 2 women, ranging in age from 25 to 75 years (mean, 55.3 years). Seven of 12 individuals were JCV antibody seropositive based on absorbance units. Serostatus was associated with amounts of JCV DNA in urine and its tissue distribution. John Cunningham virus DNA was found in 75% of genitourinary tissue samples from donors (18 of 24) with high JCV antibody levels, 13.3% of donors with low levels i(4 of 30), and 0% of seronegative persons (0 of 32). In nongenitourinary tissues, JCV DNA was detected in 45.1% of tissue samples of donors (32 of 71) with high JCV, 2.2% of donors with low JCV serostatus (2 of 93), and 0% of seronegative persons (0 of 43). Genitourinary tissues had higher copy numbers than other sites. John Cunningham virus DNA was detected in urine of seronegative individuals in a research-grade assay., Conclusions and Relevance: Persistent (latent or actively replicating) JCV infection mostly predominates in genitourinary tissues but distributes in other tissues at low copy number. The distribution and copy numbers of the virus appear to correlate with urinary JCV shedding and serostatus.

We theoretically show that a nanoelectromechanical system can be mechanically actuated by a heat flow through it via an electron-electron interaction. In contrast to most known actuation mechanisms in similar systems, this new mechanism does not involve an electronic current nor external ac fields. Instead, the mechanism relies on deflection-dependent tunneling rates and a heat flow which is mediated by an electron-electron interaction while an electronic current through the device is prohibited by, for instance, a spin-valve effect. Therefore, the system resembles a nanoelectromechanical heat engine. We derive a criterion for the mechanical instability and estimate the amplitude of the resulting self-sustained oscillations. Estimations show that the suggested phenomenon can be studied using available experimental techniques.

We show that nanomechanical vibrations in a magnetic shuttle device can be strongly affected by external microwave irradiation through photo-assisted electronic spin-flip transitions. Mechanical consequences of these spin flips are due to a spin-dependent magnetic force, which may lead to a nanomechanical instability in the device. We derive a criterion for the instability to occur and analyze different regimes of nanomechanical oscillations. Possible experimental realizations of the spin-mediated photomechanical instability and detection of the device backaction are discussed.

Objective: To assess if the percentage of CD3(+)CD4(+)CD62L(+) cells in cryopreserved peripheral blood mononuclear cells (PBMCs) (here termed %CD62L) can predict risk of developing progressive multifocal leukoencephalopathy (PML) and better inform the physician for benefit-risk assessment of natalizumab treatment decisions in a global setting., Methods: Cryopreserved PBMCs from 21 natalizumab-treated patients who developed PML and 104 matched natalizumab-treated patients with multiple sclerosis (MS) without PML collected as a part of Biogen clinical trials were retrospectively examined for CD3, CD4, CCR7, CD45RA, and CD62L by flow cytometry., Results: In this cohort, %CD62L in natalizumab-treated patients did not predict PML risk. Natalizumab-treated patients with MS without PML showed highly variable %CD62L upon serial sampling. In the STRATA study, the distribution of %CD62L in samples collected more than 6 months before a PML diagnosis, at diagnosis, and in natalizumab-treated patients without PML overlapped. No statistical threshold for risk could be determined. In addition, we demonstrated that lymphocyte viability strongly affects %CD62L, supporting previous reports that %CD62L is inherently unstable following cryopreservation and is sensitive to sample collection., Conclusion: Data from this well-controlled cohort of natalizumab-treated patients indicate that %CD62L is not a biomarker of PML risk., (© 2015 American Academy of Neurology.)

Polyomavirus JC (JCV) is the causative agent of progressive multifocal leukoencephalopathy (PML), a rare and frequently fatal brain disease that afflicts a small fraction of the immune-compromised population, including those affected by AIDS and transplantation recipients on immunosuppressive drug therapy. Currently there is no specific therapy for PML. The major capsid viral protein 1 (VP1) involved in binding to sialic acid cell receptors is believed to be a key player in pathogenesis. PML-specific mutations in JCV VP1 sequences present at the binding pocket of sialic acid cell receptors, such as L55F and S269F, abolish sialic acid recognition and might favor PML onset. Early diagnosis of these PML-specific mutations may help identify patients at high risk of PML, thus reducing the risks associated with immunosuppressive therapy. As a first step in the development of such early diagnostic tools, we report identification and characterization of affinity reagents that specifically recognize PML-specific mutations in VP1 variants using phage display technology. We first identified 2 peptides targeting wild type VP1 with moderate specificity. Fine-tuning via selection of biased libraries designed based on 2 parental peptides yielded peptides with different, yet still moderate, bindinspecificities. In contrast, we had great success in identifying synthetic antibodies that recognize one of the PML-specific mutations (L55F) with high specificity from the phage-displayed libraries. These peptides and synthetic antibodies represent potential candidates for developing tailored immune-based assays for PML risk stratification in addition to complementing affinity reagents currently available for the study of PML and JCV.

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease triggered by infection with the human gliotropic JC virus (JCV). Due to the human-selective nature of the virus, there are no animal models available to investigate JCV pathogenesis. To address this issue, we developed mice with humanized white matter by engrafting human glial progenitor cells (GPCs) into neonatal immunodeficient and myelin-deficient mice. Intracerebral delivery of JCV resulted in infection and subsequent demyelination of these chimeric mice. Human GPCs and astrocytes were infected more readily than oligodendrocytes, and viral replication was noted primarily in human astrocytes and GPCs rather than oligodendrocytes, which instead expressed early viral T antigens and exhibited apoptotic death. Engraftment of human GPCs in normally myelinated and immunodeficient mice resulted in humanized white matter that was chimeric for human astrocytes and GPCs. JCV effectively propagated in these mice, which indicates that astroglial infection is sufficient for JCV spread. Sequencing revealed progressive mutation of the JCV capsid protein VP1 after infection, suggesting that PML may evolve with active infection. These results indicate that the principal CNS targets for JCV infection are astrocytes and GPCs and that infection is associated with progressive mutation, while demyelination is a secondary occurrence, following T antigen-triggered oligodendroglial apoptosis. More broadly, this study provides a model by which to further assess the biology and treatment of human-specific gliotropic viruses.

A nanoelectromechanical device based on magnetic exchange forces and electron spin flips induced by a weak external magnetic field is suggested. It is shown that this device can operate as a new type of single-electron "shuttle" in the Coulomb blockade regime of electron transport.

We consider dc-electronic transport through a nanowire suspended between two normal-metal leads in the presence of an external magnetic field. We show the very mechanism through which such a system, whose stationary current-voltage characteristic is essentially characterized by positive differential conductance, becomes unstable with respect to an onset of self-excited oscillations in electrical transport and mechanical vibrations. The self-excitation mechanism is based on the correlation between the occupancy of the quantized spin-split electronic energy levels inside the nanowire and the velocity of the nanowire with the crucial influence of strong enough retardation effects in magnetomotive coupling coming from mechanical vibrations.

Immune reconstitution has improved outcomes for progressive multifocal leukoencephalopathy (PML), a potentially lethal brain disease caused by JC virus (JCV). However, an antiviral treatment to control JCV is needed when immune reconstitution is delayed or not possible. On the basis of in vitro efficacy, this study evaluated the effect of mefloquine on PML and factors that may predict PML outcomes. This 38-week, open-label, randomized, parallel-group, proof-of-concept study compared patients with PML who received standard of care (SOC) with those who received SOC plus mefloquine (250 mg for 3 days, then 250 mg weekly). Patients randomized to SOC could add mefloquine treatment at week 4. The primary endpoint was change from baseline to weeks 4 and 8 in JCV DNA copy number (load) in cerebrospinal fluid (CSF). Exploratory analyses evaluated factors that might correlate with clinical outcome. The majority of enrolled patients were HIV positive. Preplanned interim data analyses suggested that the study was unlikely to successfully demonstrate a significant difference between groups; therefore, the study was terminated prematurely. There was no significant difference between groups in CSF JCV DNA loads or clinical/MRI findings. Decrease in CSF JCV DNA load from baseline to week 4 was associated with a better clinical outcome at 16 weeks, as measured by Karnofsky scores. This study found no evidence of anti-JCV activity by mefloquine. An early decrease of CSF JCV DNA load appears to be associated with a better clinical outcome.

We consider the electromechanical properties of a single-electronic device consisting of a movable quantum dot attached to a vibrating cantilever, forming a tunnel contact with a nonmovable source electrode. We show that the resonance Kondo tunneling of electrons amplifies exponentially the strength of nanoelectromechanical (NEM) coupling in such a device and make the latter insensitive to mesoscopic fluctuations of electronic levels in a nanodot. It is also shown that the study of a Kondo-NEM phenomenon provides additional (as compared with standard conductance measurements in a nonmechanical device) information on retardation effects in the formation of a many-particle cloud accompanying the Kondo tunneling. A possibility for superhigh tunability of mechanical dissipation as well as supersensitive detection of mechanical displacement is demonstrated.

Background: JC virus (JCV) infection is a prerequisite for development of progressive multifocal leukoencephalopathy (PML). We previously described the development of a novel, two-step enzyme-linked immunosorbent assay (ELISA) that detects anti-JCV antibodies in human serum or plasma, and the potential clinical utility of anti-JCV antibody status for PML risk stratification., Objectives: To validate the anti-JCV antibody ELISA at multiple clinical laboratories in order to demonstrate the robustness of the method., Study Design: Analytical validation of the ELISA was performed at four laboratories by evaluation of intra- and inter-assay precision, analytical specificity and sensitivity, matrix interference, robustness, sample and reagent stability., Results: Analytical validation demonstrated that the assay is sensitive, specific, and precise. The assay sensitivity was estimated at 1.7ng/mL using a humanized anti-JCV monoclonal antibody control. The sensitivity to detect JCV infection was estimated to be 97.5%. The specificity of the assay to discriminate JCV-specific antibodies from antibodies directed to BK virus, a related polyomavirus, was also demonstrated. The inter- and intra-assay precision was ≤6.0% and 9.8% for the screening step and 2.6% and 11.3% for the confirmation step. Results obtained for plasma and serum were highly congruent, and assay robustness was demonstrated by the highly concordant results generated by four laboratories testing a common panel of 100 blinded samples., Conclusions: The novel, two-step ELISA to detect anti-JCV antibodies in human serum and plasma is robust, and assay performance is consistent and reproducible in multiple laboratories, making it suitable to support testing for global clinical studies., (Copyright © 2011 Elsevier B.V. All rights reserved.)

We consider dc-electronic transport through a nanowire suspended between normal- and spin-polarized metal leads in the presence of an external magnetic field. We show that magnetomotive coupling between the electrical current through the nanowire and vibrations of the wire may result in self-excitation of mechanical vibrations. The self-excitation mechanism is based on correlations between the occupancy of the quantized electronic energy levels inside the nanowire and the velocity of the nanowire. We derive conditions for the occurrence of the instability and find stable regimes of mechanical oscillations., (© 2011 American Physical Society)

Background: Progressive multifocal leukoencephalopathy (PML) in natalizumab-treated MS patients is linked to JC virus (JCV) infection. JCV sequence variation and rearrangements influence viral pathogenicity and tropism. To better understand PML development, we analyzed viral DNA sequences in blood, CSF and/or urine of natalizumab-treated PML patients., Methods: Using biofluid samples from 17 natalizumab-treated PML patients, we sequenced multiple isolates of the JCV noncoding control region (NCCR), VP1 capsid coding region, and the entire 5 kb viral genome., Results: Analysis of JCV from multiple biofluids revealed that individuals were infected with a single genotype. Across our patient cohort, multiple PML-associated NCCR rearrangements and VP1 mutations were present in CSF and blood, but absent from urine-derived virus. NCCR rearrangements occurred in CSF of 100% of our cohort. VP1 mutations were observed in blood or CSF in 81% of patients. Sequencing of complete JCV genomes demonstrated that NCCR rearrangements could occur without VP1 mutations, but VP1 mutations were not observed without NCCR rearrangement., Conclusions: These data confirm that JCV in natalizumab-PML patients is similar to that observed in other PML patient groups, multiple genotypes are associated with PML, individual patients appear to be infected with a single genotype, and PML-associated mutations arise in patients during PML development.

Progressive multifocal leukoencephalopathy (PML), a fatal demyelinating disease caused by JC virus (JCV) infection of oligodendrocytes, may develop in patients with immune disorders following reactivation of chronic benign infection. Mutations of JCV capsid viral protein 1 (VP1), the capsid protein involved in binding to sialic acid cell receptors, might favor PML onset. Cerebrospinal fluid sequences from 37/40 PML patients contained one of several JCV VP1 amino acid mutations, which were also present in paired plasma but not urine sequences despite the same viral genetic background. VP1-derived virus-like particles (VLPs) carrying these mutations lost hemagglutination ability, showed different ganglioside specificity, and abolished binding to different peripheral cell types compared with wild-type VLPs. However, mutants still bound brain-derived cells, and binding was not affected by sialic acid removal by neuraminidase. JCV VP1 substitutions are acquired intrapatient and might favor JCV brain invasion through abrogation of sialic acid binding with peripheral cells, while maintaining sialic acid-independent binding with brain cells.

We show that the vibrations of a nanomechanical resonator can be cooled to near its quantum ground state by tunneling injection of electrons from a scanning tunneling microscope tip. The interplay between two mechanisms for coupling the electronic and mechanical degrees of freedom results in a bias-voltage-dependent difference between the probability amplitudes for vibron emission and absorption during tunneling. For a bias voltage just below the Coulomb blockade threshold, we find that absorption dominates, which leads to cooling corresponding to an average vibron population of the fundamental bending mode of 0.2.

Objective: Analyses were conducted to determine the clinical utility of measuring JC virus (JCV) DNA in blood or urine of natalizumab-treated multiple sclerosis (MS) patients to predict the risk of progressive multifocal leukoencephalopathy (PML)., Methods: A total of 12,850 blood and urine samples from nearly 1,400 patients participating in natalizumab clinical trials were tested for JCV DNA using a commercially available quantitative polymerase chain reaction (qPCR) assay. A subset of these samples was also tested using a more sensitive qPCR assay developed at the National Institutes of Health (NIH)., Results: At the time natalizumab dosing was suspended, JCV DNA was detected in plasma by the commercial assay in 4 of 1,397 (0.3%) patients; the NIH assay confirmed these positive samples and detected JCV DNA in an additional 2 of 205 (1%) patients who tested negative with the commercial assay. None of these 6 JCV DNA positive patients developed PML. In a 48-week study testing the safety of natalizumab redosing, JCV DNA was detected in plasma of 6 of 1,094 (0.3%) patients, none of whom developed PML. Urine at baseline and week 48 was assessed in 224 patients; 58 (26%) were positive at baseline, and 55 (25%) were positive after 48 weeks of natalizumab, treatment. JCV DNA was not detected in peripheral blood mononuclear cells from any of these 1,094 patients before or after natalizumab treatment. In 5 patients who developed PML, JCV DNA was not detected in blood at any time point before symptoms first occurred., Interpretation: Measuring JCV DNA in blood or urine with currently available methods is unlikely to be useful for predicting PML risk in natalizumab-treated MS patients.

Objective: A study was undertaken to establish an enzyme-linked immunosorbent assay (ELISA) to detect JC virus (JCV)-specific antibodies in multiple sclerosis (MS) patients, and to evaluate its potential utility for identifying patients at higher or lower risk (ie, risk stratification) of developing progressive multifocal leukoencephalopathy (PML)., Methods: A 2-step assay for detecting and confirming the presence of anti-JCV antibodies in human serum and plasma was developed and demonstrated to be both sensitive and specific. ELISA cutpoints were statistically established using sera from >800 MS patients from natalizumab clinical studies. Subsequently, this assay was used to determine the presence of anti-JCV antibodies in natalizumab-treated PML patients where serum samples were collected 16-180 months prior to the diagnosis of PML., Results: In our evaluation of natalizumab-treated MS patients, 53.6% tested positive for anti-JCV antibodies, with a 95% confidence interval of 49.9 to 57.3%. The false-negative rate of the ELISA was calculated to be approximately 2.5%, with an upper 1-sided confidence limit of 4.4%. Notably, we observed anti-JCV antibodies in all 17 available pre-PML sera samples, which was significantly different from the 53.6% seropositivity observed in the overall MS study population (p < 0.0001)., Interpretation: This 2-step assay provides a means to classify MS patients as having detectable or not detectable levels of anti-JCV antibodies. The finding that all 17 of the pre-PML samples that were available tested seropositive, and none tested seronegative, warrants further research on the clinical utility of the anti-JCV antibody assay as a potential tool for stratifying MS patients for higher or lower risk of developing PML.

Progressive multifocal leukoencephalopathy (PML) is a rare but frequently fatal disease caused by the uncontrolled replication of JC virus (JCV), a polyomavirus, in the brains of some immunocompromised individuals. Currently, no effective antiviral treatment for this disease has been identified. As a first step in the identification of such therapy, we screened the Spectrum collection of 2,000 approved drugs and biologically active molecules for their anti-JCV activities in an in vitro infection assay. We identified a number of different drugs and compounds that had significant anti-JCV activities at micromolar concentrations and lacked cellular toxicity. Of the compounds with anti-JCV activities, only mefloquine, an antimalarial agent, has been reported to show sufficiently high penetration into the central nervous system such that it would be predicted to achieve efficacious concentrations in the brain. Additional in vitro experiments demonstrated that mefloquine inhibits the viral infection rates of three different JCV isolates, JCV(Mad1), JCV(Mad4), and JCV(M1/SVEDelta), and does so in three different cell types, transformed human glial (SVG-A) cells, primary human fetal glial cells, and primary human astrocytes. Using quantitative PCR to quantify the number of viral copies in cultured cells, we have also shown that mefloquine inhibits viral DNA replication. Finally, we demonstrated that mefloquine does not block viral cell entry; rather, it inhibits viral replication in cells after viral entry. Although no suitable animal model of PML or JCV infection is available for the testing of mefloquine in vivo, our in vitro results, combined with biodistribution data published in the literature, suggest that mefloquine could be an effective therapy for PML.

Background: Atopic dermatitis and allergic contact dermatitis are skin disorders triggered by epicutaneous sensitization with protein antigens and contact sensitization with haptens, respectively. Skin is colonized with bacteria, which are a source of Toll-like receptor (TLR) 2 ligands., Objective: We sought to examine the role of TLR2 in murine models of atopic dermatitis and allergic contact dermatitis., Methods: TLR2(-/-) mice and wild-type littermates were epicutaneously sensitized with ovalbumin (OVA) or contact sensitized with oxazolone (OX). Skin histology was assessed by means of hematoxylin and eosin staining and immunohistochemistry. Ear swelling was measured with a micrometer. Cytokine mRNA expression was examined by means of quantitative RT-PCR. Antibody levels and splenocyte secretion of cytokines in response to OVA stimulation were measured by means of ELISA. Dendritic cells were examined for their ability to polarize T-cell receptor/OVA transgenic naive T cells to T(H)1 and T(H)2., Results: In response to OVA sensitization, TLR2(-/-) mice experienced skin infiltration with eosinophils and CD4(+) cells, as well as upregulation of T(H)2 cytokine mRNAs that was comparable with that seen in wild-type littermates. In contrast, epidermal thickening, IFN-gamma expression in the skin, IFN-gamma production by splenocytes, and IgG2a anti-OVA antibody levels were impaired in TLR2(-/-) mice. After OX ear challenge, contact sensitized TLR2(-/-) mice exhibited defective ear swelling with impaired cellular infiltration, decreased epidermal thickening and local IFN-gamma expression, and impaired OX-specific IgG2a responses. Dendritic cells from TLR2(-/-) mice induced significantly lower production of IFN-gamma but normal IL-4 and IL-13 production in naive T cells., Conclusions: These results indicate that TLR2 promotes the IFN-gamma response to cutaneously introduced antigens.

PML is a progressive and mostly fatal demyelinating disease caused by JC virus infection and destruction of infected oligodendrocytes in multiple brain foci of susceptible individuals. While JC virus is highly prevalent in the human population, PML is a rare disease that exclusively afflicts only a small percentage of immunocompromised individuals including those affected by HIV (AIDS) or immunosuppressive drugs. Viral- and/or host-specific factors, and not simply immune status, must be at play to account for the very large discrepancy between viral prevalence and low disease incidence. Here, we show that several amino acids on the surface of the JC virus capsid protein VP1 display accelerated evolution in viral sequences isolated from PML patients but not in sequences isolated from healthy subjects. We provide strong evidence that at least some of these mutations are involved in binding of sialic acid, a known receptor for the JC virus. Using statistical methods of molecular evolution, we performed a comprehensive analysis of JC virus VP1 sequences isolated from 55 PML patients and 253 sequences isolated from the urine of healthy individuals and found that a subset of amino acids found exclusively among PML VP1 sequences is acquired via adaptive evolution. By modeling of the 3-D structure of the JC virus capsid, we showed that these residues are located within the sialic acid binding site, a JC virus receptor for cell infection. Finally, we go on to demonstrate the involvement of some of these sites in receptor binding by demonstrating a profound reduction in hemagglutination properties of viral-like particles made of the VP1 protein carrying these mutations. Collectively, these results suggest that a more virulent PML causing phenotype of JC virus is acquired via adaptive evolution that changes viral specificity for its cellular receptor(s)., Competing Interests: In the interests of transparency and to help readers to form their own judgements of potential bias, we would like to declare potential competing interests as Alexey Lugovskoy, Kenneth Simon, and Leonid Gorelik are currently employed by and possess shares of Biogen IDEC Inc; Shamil R. Sunyaev has a consulting agreement with Biogen IDEC Inc.

We have shown previously that inhalation of cowshed dust extract (CDE) resulted in decreased airway reactivity, eosinophilic inflammation and sensitization in a mouse model of allergic asthma. Our data suggested down-regulation of allergic immune response rather than activation of a Th1 response towards the model allergen. However, the precise mechanism of allergy protection is not yet understood in detail. To gain deeper insight into CDE-induced immune modulation, we have analysed the effects of CDE on dendritic cell biology. Dendritic cells were generated from murine bone marrow cells (BMDC). Cells were stimulated with CDE and subsequently used to sensitize mice via the airways. Our results showed that cells were not able to prime mice for allergic immune response when they were treated with CDE 2 days before pulsing with allergen, whereas cells that were stimulated with CDE simultaneously to OVA pulsing induced a fully developed allergic immune response. Surprisingly, CDE-treated cells that were not able to prime mice for allergic immune response exhibit an activated phenotype with high expression of the co-stimulatory surface molecule CD86. Moreover, CDE-treated cells transiently produced high amounts of cytokines such as IL-10, IL-12p70 and TNF-alpha. Interestingly, blocking of autocrine-produced IL-10 in vitro partially restored the allergy-inducing capacity of CDE-exposed cells. Thus, we conclude that prolonged exposure to CDE reduces the allergy-inducing capacity of dendritic cells. Furthermore, we present evidence that an autocrine IL-10 dependent mechanism seems to be involved in down-regulation of dendritic cell function due to stimulation with CDE.

We investigate theoretically multimode electromechanical "shuttle" instabilities in dc voltage-biased nanoelectromechanical single-electron tunneling devices. We show that initially irregular (quasiperiodic) oscillations that occur as a result of the simultaneous self-excitation of several mechanical modes with incommensurable frequencies self-organize into periodic oscillations with a frequency corresponding to the eigenfrequency of one of the unstable modes. This effect demonstrates that a local probe can selectively excite global vibrations of extended objects.

Unmethylated CpG-oligodeoxynucleotides (ODNs) are generally thought of as potent adjuvants with considerable therapeutic potential to enhance immune responses against microbes and tumors. Surprisingly, certain so-called stimulatory CpG-ODNs strongly inhibited the effector phase of inflammatory arthritis in the K/BxN serum transfer system, either preventively or therapeutically. Also unexpected was that the inhibitory influence did not depend on the adaptive immune system cells mobilized in an immunostimulatory context. Instead, they relied on cells of the innate immune system, specifically on cross talk between CD8 alpha(+) dendritic cells and natural killer cells, resulting in suppression of neutrophil recruitment to the joint, orchestrated through interleukin-12 and interferon-gamma. These findings highlight potential applications of CpG-ODNs and downstream molecules as antiinflammatory agents.

Mechanical displacements of a nanoelectromechanical system shift the electron trajectories and hence perturb phase coherent charge transport through the device. We show theoretically that in the presence of a magnetic field such quantum-coherent displacements may give rise to an Aharonov-Bohm-type of effect. In particular, we demonstrate that quantum vibrations of a suspended carbon nanotube result in a positive nanotube magnetoresistance, which decreases slowly with the increase of temperature. This effect may enable one to detect quantum displacement fluctuations of a nanomechanical device.

In this paper, we develop a physical analysis of charge transfer in the model 'metallo-enzyme' complex which consists of a synthetic redox-addressed assembly (a 'reaction center') hybridized with a quantum dot (a gold nanoparticle) and attached via molecular bridge (a spacer) to the electrode. This artificial system allows us to model electronic transduction in experimental redox ezyme-gold nanoparticle hybrid structure recently reported by Xiao et al. [Xiao, Y., Patolsky, F., Katz, E., Hainfeid, J.F., Willner, I., 2003. Science 299, 1877-1881]. We consider a photosensitive spacer that allows us to control the conductivity of the bridge by light. In this paper we will focus on a special type of nanoelectro-mechanical processes in this system and investigate single electronic effects in there.

Mice deficient in the E3 ubiquitin ligase Cbl-b have CD28-independent T cells and develop autoimmunity. We previously reported that Cbl-b-/- CD4+CD25- T effector cells are resistant in vitro to the antiproliferative effects of CD4+CD25+ regulatory T cells and TGF-beta. We have now asked whether the resistance noted in Cbl-b-/- T cells is restricted solely to TGF-beta's antiproliferative effects, whether the TGF-beta resistance has in vivo relevance, and whether a defect can be identified in the TGF-beta signaling pathway. We now demonstrate the following: 1) in vitro, Cbl-b deficiency prevents the TGF-beta-mediated induction of Foxp3+ functional regulatory T cells; 2) in vivo, Cbl-b-/- mice show a significantly enhanced response to a tumor that is strictly TGF-beta regulated; and 3) Cbl-b-/- T effector cells have defective TGF-beta-mediated Smad2 phosphorylation. These studies are the first to document that the E3 ubiquitin ligase Cbl-b plays an integral role in T cell TGF-beta signaling, and that its absence results in multifunctional TGF-beta-related defects that have important disease-related implications.

T cell homeostasis is required for normal immune responses and prevention of pathological responses. Transforming growth factor beta (TGFbeta) plays an essential role in that regulation. Owing to its broad expression and inhibitory effects on multiple immune cell types, TGFbeta regulation is complex. Through recent advances in cell-specific targeting of TGFbeta signaling in vivo, the role of TGFbeta in T cell regulation is emerging. We demonstrated here a critical role for TGFbeta in regulating effector vs regulatory T cell homeostasis.

We study transport of spin-polarized electrons through a magnetic single-electron transistor (SET) in the presence of an external magnetic field. Assuming the SET to have a nanometer size central island with a single-electron level we find that the interplay on the island between coherent spin-flip dynamics and Coulomb interactions can make the Coulomb correlations promote rather than suppress the current through the device. We find the criteria for this new phenomenon--Coulomb promotion of spin-dependent tunneling--to occur.

We consider effects of the spin degree of freedom on the nanomechanics of a single-electron transistor (SET) containing a nanometer-sized metallic cluster suspended between two magnetic leads. It is shown that in such a nanoelectromechanical SET (NEM-SET) the onset of an electromechanical instability leading to cluster vibrations and shuttle transport of electrons between the leads can be controlled by an external magnetic field. Different stable regimes of this spintronic NEM-SET operation are analyzed. Two different scenarios for the onset of shuttle vibrations are found.