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1.
Nature ; 569(7756): 388-392, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31043748

RESUMO

Resistive switching, a phenomenon in which the resistance of a device can be modified by applying an electric field1-5, is at the core of emerging technologies such as neuromorphic computing and resistive memories6-9. Among the different types of resistive switching, threshold firing10-14 is one of the most promising, as it may enable the implementation of artificial spiking neurons7,13,14. Threshold firing is observed in Mott insulators featuring an insulator-to-metal transition15,16, which can be triggered by applying an external voltage: the material becomes conducting ('fires') if a threshold voltage is exceeded7,10-12. The dynamics of this induced transition have been thoroughly studied, and its underlying mechanism and characteristic time are well documented10,12,17,18. By contrast, there is little knowledge regarding the opposite transition: the process by which the system returns to the insulating state after the voltage is removed. Here we show that Mott nanodevices retain a memory of previous resistive switching events long after the insulating resistance has recovered. We demonstrate that, although the device returns to its insulating state within 50 to 150 nanoseconds, it is possible to re-trigger the insulator-to-metal transition by using subthreshold voltages for a much longer time (up to several milliseconds). We find that the intrinsic metastability of first-order phase transitions is the origin of this phenomenon, and so it is potentially present in all Mott systems. This effect constitutes a new type of volatile memory in Mott-based devices, with potential applications in resistive memories, solid-state frequency discriminators and neuromorphic circuits.

2.
Proc Natl Acad Sci U S A ; 118(9)2021 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-33622788

RESUMO

Vanadium dioxide (VO2) has attracted much attention owing to its metal-insulator transition near room temperature and the ability to induce volatile resistive switching, a key feature for developing novel hardware for neuromorphic computing. Despite this interest, the mechanisms for nonvolatile switching functioning as synapse in this oxide remain not understood. In this work, we use in situ transmission electron microscopy, electrical transport measurements, and numerical simulations on Au/VO2/Ge vertical devices to study the electroforming process. We have observed the formation of V5O9 conductive filaments with a pronounced metal-insulator transition and that vacancy diffusion can erase the filament, allowing for the system to "forget." Thus, both volatile and nonvolatile switching can be achieved in VO2, useful to emulate neuronal and synaptic behaviors, respectively. Our systematic operando study of the filament provides a more comprehensive understanding of resistive switching, key in the development of resistive switching-based neuromorphic computing.

3.
Mod Pathol ; 36(10): 100247, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37307876

RESUMO

Microscopic examination of prostate cancer has failed to reveal a reproducible association between molecular and morphologic features. However, deep-learning algorithms trained on hematoxylin and eosin (H&E)-stained whole slide images (WSI) may outperform the human eye and help to screen for clinically-relevant genomic alterations. We created deep-learning algorithms to identify prostate tumors with underlying ETS-related gene (ERG) fusions or PTEN deletions using the following 4 stages: (1) automated tumor identification, (2) feature representation learning, (3) classification, and (4) explainability map generation. A novel transformer-based hierarchical architecture was trained on a single representative WSI of the dominant tumor nodule from a radical prostatectomy (RP) cohort with known ERG/PTEN status (n = 224 and n = 205, respectively). Two distinct vision transformer-based networks were used for feature extraction, and a distinct transformer-based model was used for classification. The ERG algorithm performance was validated across 3 RP cohorts, including 64 WSI from the pretraining cohort (AUC, 0.91) and 248 and 375 WSI from 2 independent RP cohorts (AUC, 0.86 and 0.89, respectively). In addition, we tested the ERG algorithm performance in 2 needle biopsy cohorts comprised of 179 and 148 WSI (AUC, 0.78 and 0.80, respectively). Focusing on cases with homogeneous (clonal) PTEN status, PTEN algorithm performance was assessed using 50 WSI reserved from the pretraining cohort (AUC, 0.81), 201 and 337 WSI from 2 independent RP cohorts (AUC, 0.72 and 0.80, respectively), and 151 WSI from a needle biopsy cohort (AUC, 0.75). For explainability, the PTEN algorithm was also applied to 19 WSI with heterogeneous (subclonal) PTEN loss, where the percentage tumor area with predicted PTEN loss correlated with that based on immunohistochemistry (r = 0.58, P = .0097). These deep-learning algorithms to predict ERG/PTEN status prove that H&E images can be used to screen for underlying genomic alterations in prostate cancer.

4.
BMC Biol ; 20(1): 197, 2022 10 22.
Artigo em Inglês | MEDLINE | ID: mdl-36271358

RESUMO

BACKGROUND: By 2016, signs of emergence of Plasmodium falciparum resistance to artemisinin and partner drugs were detected in the Greater Mekong Subregion. Recently, the independent evolution of artemisinin resistance has also been reported in Africa and South America. This alarming scenario calls for the urgent development of new antimalarials with novel modes of action. We investigated the interference with protein aggregation, which is potentially toxic for the cell and occurs abundantly in all Plasmodium stages, as a hitherto unexplored drug target in the pathogen. RESULTS: Attempts to exacerbate the P. falciparum proteome's propensity to aggregation by delivering endogenous aggregative peptides to in vitro cultures of this parasite did not significantly affect their growth. In contrast, protein aggregation inhibitors clearly reduced the pathogen's viability. One such compound, the bis(styrylpyridinium) salt YAT2150, exhibited potent antiplasmodial activity with an in vitro IC50 of 90 nM for chloroquine- and artemisinin-resistant lines, arresting asexual blood parasites at the trophozoite stage, as well as interfering with the development of both sexual and hepatic forms of Plasmodium. At its IC50, this compound is a powerful inhibitor of the aggregation of the model amyloid ß peptide fragment 1-40, and it reduces the amount of aggregated proteins in P. falciparum cultures, suggesting that the underlying antimalarial mechanism consists in a generalized impairment of proteostasis in the pathogen. YAT2150 has an easy, rapid, and inexpensive synthesis, and because it fluoresces when it accumulates in its main localization in the Plasmodium cytosol, it is a theranostic agent. CONCLUSIONS: Inhibiting protein aggregation in Plasmodium significantly reduces the parasite's viability in vitro. Since YAT2150 belongs to a novel structural class of antiplasmodials with a mode of action that potentially targets multiple gene products, rapid evolution of resistance to this drug is unlikely to occur, making it a promising compound for the post-artemisinin era.


Assuntos
Antimaláricos , Artemisininas , Malária Falciparum , Humanos , Antimaláricos/farmacologia , Plasmodium falciparum , Agregados Proteicos , Peptídeos beta-Amiloides , Proteoma , Resistência a Medicamentos , Artemisininas/farmacologia , Artemisininas/uso terapêutico , Malária Falciparum/parasitologia , Cloroquina/química , Cloroquina/farmacologia , Cloroquina/uso terapêutico
5.
Nano Lett ; 22(3): 1251-1256, 2022 02 09.
Artigo em Inglês | MEDLINE | ID: mdl-35061947

RESUMO

Probabilistic computing is a paradigm in which data are not represented by stable bits, but rather by the probability of a metastable bit to be in a particular state. The development of this technology has been hindered by the availability of hardware capable of generating stochastic and tunable sequences of "1s" and "0s". The options are currently limited to complex CMOS circuitry and, recently, magnetic tunnel junctions. Here, we demonstrate that metal-insulator transitions can also be used for this purpose. We use an electrical pump/probe protocol and take advantage of the stochastic relaxation dynamics in VO2 to induce random metallization events. A simple latch circuit converts the metallization sequence into a random stream of 1s and 0s. The resetting pulse in between probes decorrelates successive events, providing a true stochastic digital sequence.


Assuntos
Metais , Probabilidade
6.
Circulation ; 143(23): 2229-2240, 2021 06 08.
Artigo em Inglês | MEDLINE | ID: mdl-33619968

RESUMO

BACKGROUND: Stroke remains a devastating complication of transcatheter aortic valve replacement (TAVR), which has persisted despite refinements in technique and increased operator experience. While cerebral embolic protection devices (EPDs) have been developed to mitigate this risk, data regarding their impact on stroke and other outcomes after TAVR are limited. METHODS: We performed an observational study using data from the Society for Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy Registry. Patients were included if they underwent elective or urgent transfemoral TAVR between January 2018 and December 2019. The primary outcome was in-hospital stroke. To adjust for confounding, the association between EPD use and clinical outcomes was evaluated using instrumental variable analysis, a technique designed to support causal inference from observational data, with site-level preference for EPD use within the same quarter of the procedure as the instrument. We also performed a propensity score-based secondary analysis using overlap weights. RESULTS: Our analytic sample included 123 186 patients from 599 sites. The use of EPD during TAVR increased over time, reaching 28% of sites and 13% of TAVR procedures by December 2019. There was wide variation in EPD use across hospitals, with 8% of sites performing >50% of TAVR procedures with an EPD and 72% performing no procedures with an EPD in the last quarter of 2019. In our primary analysis using the instrumental variable model, there was no association between EPD use and in-hospital stroke (adjusted relative risk, 0.90 [95% CI, 0.68-1.13]; absolute risk difference, -0.15% [95% CI, -0.49 to 0.20]). However, in our secondary analysis using the propensity score-based model, EPD use was associated with 18% lower odds of in-hospital stroke (adjusted odds ratio, 0.82 [95% CI, 0.69-0.97]; absolute risk difference, -0.28% [95% CI, -0.52 to -0.03]). Results were generally consistent across the secondary end points, as well as subgroup analyses. CONCLUSIONS: In this nationally representative observational study, we did not find an association between EPD use for TAVR and in-hospital stroke in our primary instrumental variable analysis, and found only a modestly lower risk of in-hospital stroke in our secondary propensity-weighted analysis. These findings provide a strong basis for large-scale randomized, controlled trials to test whether EPDs provide meaningful clinical benefit for patients undergoing TAVR.


Assuntos
Estenose da Valva Aórtica/cirurgia , Dispositivos de Proteção Embólica/efeitos adversos , Acidente Vascular Cerebral/patologia , Substituição da Valva Aórtica Transcateter/métodos , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Razão de Chances , Pontuação de Propensão , Sistema de Registros , Fatores de Risco , Acidente Vascular Cerebral/etiologia , Substituição da Valva Aórtica Transcateter/instrumentação , Resultado do Tratamento
7.
J Urol ; 208(6): 1182-1193, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36006048

RESUMO

PURPOSE: The prognostic value for metastasis of the cell-cycle progression score and phosphatase and tensin homolog haven't been evaluated jointly in contemporary men with exclusively intermediate- or high-risk prostate cancer. We evaluated associations of cell-cycle progression and phosphatase and tensin homolog with metastasis-free survival in contemporary intermediate/high-risk prostate cancer patients overall, and intermediate/high-risk men receiving salvage radiotherapy. MATERIALS AND METHODS: In a case-cohort of 209 prostatectomy patients with intermediate/high-risk prostate cancer, and a cohort of 172 such men who received salvage radiotherapy, cell-cycle progression score was calculated from RNA expression, and phosphatase and tensin homolog was analyzed by immunohistochemistry. Proportional hazards regression, weighted for case-cohort design or unweighted for the salvage radiotherapy cohort, was used to evaluate associations of cell-cycle progression, phosphatase and tensin homolog with metastasis-free survival. Improvement in model discrimination was evaluated with the concordance index. RESULTS: In the case-cohort 41 men had metastasis, and 17 developed metastasis in the salvage radiotherapy cohort, at median follow-up of 3 and 4 years, respectively. For both case-cohort and salvage radiotherapy cohort, cell-cycle progression was independently associated with metastasis-free survival after adjustment for Cancer of the Prostate Risk Assessment Post-Surgical: hazard ratio (95% confidence interval) = 3.11 (1.70-5.69) and 1.85 (1.19-2.85), respectively. Adding cell-cycle progression to Cancer of the Prostate Risk Assessment Post-Surgical increased the concordance index from 0.861 to 0.899 (case-cohort), and 0.745 to 0.819 (salvage radiotherapy cohort). Although statistically significant in univariate analyses, phosphatase and tensin homolog was no longer significant after adjustment for Cancer of the Prostate Risk Assessment Post-Surgical. Analysis of interaction with National Comprehensive Cancer Network risk group showed that cell-cycle progression had the strongest effect among unfavorable intermediate-risk men. CONCLUSIONS: In the first study to evaluate metastasis risk associated with cell-cycle progression and phosphatase and tensin homolog in exclusively intermediate/high-risk prostate cancer, and in such men with salvage radiotherapy, cell-cycle progression but not phosphatase and tensin homolog was associated with significantly increased 2- to 3-fold risk of metastasis after Cancer of the Prostate Risk Assessment Post-Surgical adjustment.


Assuntos
Neoplasias da Próstata , Masculino , Humanos , Tensinas , Neoplasias da Próstata/patologia , Prognóstico , Monoéster Fosfórico Hidrolases , Recidiva Local de Neoplasia/cirurgia , Estudos Retrospectivos , Terapia de Salvação , Prostatectomia , Antígeno Prostático Específico , Ciclo Celular
8.
Catheter Cardiovasc Interv ; 100(4): 553-559, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35989487

RESUMO

OBJECTIVES: To evaluate the feasibility and safety of coronary orbital atherectomy (OA) for the treatment of calcified ostial lesions. BACKGROUND: Percutaneous coronary intervention (PCI) is increasingly being completed in complex patients and lesions. OA is effective for severely calcified coronary lesions; however, there is a dearth of evidence on the use of OA in ostial lesions, especially with long-term outcome data. METHODS: Data were obtained from a retrospective analysis of patients who underwent OA of heavily calcified ostial lesions followed by stent implantation from December 2010 to June 2019 at two high-volume PCI centers. Kaplan-Meier analysis was utilized to assess the primary endpoints of 30-day, 1-year, and 2-year freedom-from (FF) major adverse cardiac events (MACE: death, myocardial infarction, or target vessel revascularization), stroke, and stent thrombosis (ST). RESULTS: A total of 56 patients underwent OA to treat heavily calcified ostial coronary lesions. The mean age was 72 years with a high prevalence of diabetes (55%) and heart failure (36%), requiring hemodynamic support (14%). There was high FF angiographic complications (93%), and at 30-day, 1-year, and 2-year, a high FF-MACE (96%, 91%, and 88%), stroke (98%, 96%, and 96%), and ST (100%), respectively. CONCLUSIONS: This study represents the largest real-world experience of coronary OA use in heavily calcified ostial lesions with long-term outcomes over 2 years. The main finding in this retrospective analysis is that, despite the complex patients and lesions included in this analysis, OA appears to be a feasible and safe treatment option for calcified coronary ostial lesions.


Assuntos
Aterectomia Coronária , Doença da Artéria Coronariana , Intervenção Coronária Percutânea , Acidente Vascular Cerebral , Trombose , Calcificação Vascular , Idoso , Aterectomia , Aterectomia Coronária/efeitos adversos , Angiografia Coronária , Doença da Artéria Coronariana/diagnóstico por imagem , Doença da Artéria Coronariana/etiologia , Doença da Artéria Coronariana/terapia , Humanos , Intervenção Coronária Percutânea/efeitos adversos , Estudos Retrospectivos , Índice de Gravidade de Doença , Acidente Vascular Cerebral/etiologia , Trombose/etiologia , Resultado do Tratamento , Calcificação Vascular/diagnóstico por imagem , Calcificação Vascular/etiologia , Calcificação Vascular/terapia
9.
Catheter Cardiovasc Interv ; 99(2): 480-488, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34847279

RESUMO

OBJECTIVES: We aimed to compare clinical characteristics and procedural outcomes of left main percutaneous interventions (LM-PCI) by transradial (TRA) versus transfemoral (TFA) approach in the VA healthcare system. BACKGROUND: TRA for percutaneous coronary intervention (PCI) is steadily increasing. However, the frequency and efficacy of TRA for LM-PCI remain less studied. METHODS: All LM-PCIs performed in the VA healthcare system were identified for fiscal year 2008 through 2018. Patients' baseline characteristics and procedure-related variables were compared by access site. Both short- and long-term clinical outcomes were analyzed using propensity score matching. RESULTS: A total of 4004 LM-PCI were performed in the VA via either radial or femoral access from 2008 to 2018. Among these, 596 (14.9%) LM PCIs were performed via TRA. Use of TRA for LM-PCI increased from 2.2% to 31.5% over the study period. Propensity matched outcome analysis, comparing TRA versus TFA, showed a similar procedural success (98.4% for TRA vs. 97.8% for TFA; RR: 1.01 [0.98, 1.03]) and 1-year major adverse cardiovascular events (MACE) (25.9% for TRA vs. 26.8% TFA; RR: 0.96 [0.74, 1.25]). There were no statistically significant differences among secondary outcomes analyses including major bleeding. CONCLUSION: Use of TRA for LM-PCI has been steadily increasing in the VA healthcare system. These findings demonstrate similar procedural success and 1-year MACE across access strategies, suggesting an opportunity to continue increasing TRA use for LM-PCI.


Assuntos
Cateterismo Periférico , Intervenção Coronária Percutânea , Veteranos , Cateterismo Periférico/efeitos adversos , Artéria Femoral/diagnóstico por imagem , Humanos , Intervenção Coronária Percutânea/efeitos adversos , Artéria Radial , Resultado do Tratamento
10.
Proc Natl Acad Sci U S A ; 116(18): 8798-8802, 2019 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-30975746

RESUMO

Controlling the electronic properties of oxides that feature a metal-insulator transition (MIT) is a key requirement for developing a new class of electronics often referred to as "Mottronics." A simple, controllable method to switch the MIT properties in real time is needed for practical applications. Here we report a giant, nonvolatile resistive switching (ΔR/R > 1,000%) and strong modulation of the MIT temperature (ΔTc > 30 K) in a voltage-actuated V2O3/PMN-PT [Pb(Mg,Nb)O3-PbTiO3] heterostructure. This resistive switching is an order of magnitude larger than ever encountered in any other similar systems. The control of the V2O3 electronic properties is achieved using the transfer of switchable ferroelastic strain from the PMN-PT substrate into the epitaxially grown V2O3 film. Strain can reversibly promote/hinder the structural phase transition in the V2O3, thus advancing/suppressing the associated MIT. The giant resistive switching and strong Tc modulation could enable practical implementations of voltage-controlled Mott devices and provide a platform for exploring fundamental electronic properties of V2O3.

11.
J Gerontol Soc Work ; 65(6): 589-603, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34809525

RESUMO

Social workers in healthcare settings often support patient decision-making processes for complex medical decisions. The objective of this study was to examine decision support needs for patients considering aortic valve replacement (AVR) for aortic stenosis. Seventeen qualitative interviews were conducted to explore treatment decision experiences of patients who accepted AVR. Analysis was conducted using a mixed inductive-deductive approach. Fear was a prevalent response for most participants in the face of AVR. Two general paths of decision making emerged: an "active" information seeking approach, or a "passive" simplicity seeking approach. Patients with unique clinical presentations felt alienated by the decision-making process. Acknowledging fear while understanding different decision-making styles provide opportunities for social workers and other members of multidisciplinary teams to support complex patient decisions.


Assuntos
Estenose da Valva Aórtica , Implante de Prótese de Valva Cardíaca , Valva Aórtica/cirurgia , Estenose da Valva Aórtica/cirurgia , Tomada de Decisões , Humanos
12.
Am J Pathol ; 190(7): 1565-1579, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32304697

RESUMO

Mitochondria regulate ATP production, metabolism, and cell death. Alterations in mitochondrial DNA (mtDNA) sequence and copy number are implicated in aging and organ dysfunction in diverse inherited and sporadic diseases. Because most measurements of mtDNA use homogenates of complex tissues, little is known about cell-type-specific mtDNA copy number heterogeneity in normal physiology, aging, and disease. Thus, the precise cell types whose loss of mitochondrial activity and altered mtDNA copy number that result in organ dysfunction in aging and disease have often not been clarified. Here, an in situ hybridization approach to generate a single-cell-resolution atlas of mtDNA content in mammalian tissues was validated. In hierarchically organized self-renewing tissues, higher levels of mtDNA were observed in stem/proliferative compartments compared with differentiated compartments. Striking zonal patterns of mtDNA levels in the liver reflected the known oxygen tension gradient. In the kidney, proximal and distal tubules had markedly higher mtDNA levels compared with cells within glomeruli and collecting duct epithelial cells. In mice, decreased mtDNA levels were visualized in renal tubules as a function of aging, which was prevented by calorie restriction. This study provides a novel approach for quantifying species- and cell-type-specific mtDNA copy number and dynamics in any normal or diseased tissue that can be used for monitoring the effects of interventions in animal and human studies.


Assuntos
Proliferação de Células , DNA Mitocondrial/análise , Células-Tronco , Envelhecimento/fisiologia , Animais , Atlas como Assunto , Variações do Número de Cópias de DNA , Feminino , Humanos , Hibridização In Situ/métodos , Masculino , Camundongos , Camundongos Endogâmicos C57BL
13.
Diabetes Obes Metab ; 23(1): 97-105, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32902128

RESUMO

AIM: To assess the unrealized potential of glucagon-like peptide-1 receptor agonist (GLP-1RA) or sodium-glucose co-transport-2 inhibitor (SGLT2i) use to reduce mortality in veterans with type 2 diabetes (T2D), coronary artery disease (CAD), and other characteristics congruent with clinical trial cohorts that established the efficacy of these agents. METHODS: Veterans with T2D and CAD on angiography in 2014 who were untreated with either a GLP-1RA or a SGLT2i were assessed for key eligibility criteria of the LEADER (GLP-1RA) and EMPA-REG OUTCOME (SGLT2i) trials. Trial hazard ratios and 95% confidence intervals for all-cause death were applied to deaths observed in veterans through 2018 to estimate the potential benefit of GLP-1RA or SGLT2i use. RESULTS: Median observation was 4.3 years. Of 15 987 veterans with T2D and CAD, 1186 (7.4%) were excluded for GLP-1RA or SGLT2i treatment, and 1386 lacked glycated haemoglobin measurement. Of the remaining 13 415 patients, 4103 (30.1%) and 5313 (39.6%) fulfilled the key criteria for the LEADER and EMPA-REG OUTCOME trials, respectively. Death occurred in 1009 (24.6%) of LEADER-eligible patients and 1335 (25.1%) of EMPA-REG OUTCOME-eligible patients. Under treatment with liraglutide in LEADER-eligible veterans, a 3.5% (0.7%-6.2%) potential absolute mortality reduction, corresponding to 144 (28-253) fewer deaths (0.88 [0.17-1.56] per 100 person-years), might have been expected. Similarly, under treatment with empagliflozin in EMPA-REG OUTCOME-eligible veterans, a 7.9% (4.5%-10.8%) potential absolute mortality reduction, corresponding to 418 (230-573) fewer deaths (1.98 [1.14-2.72] per 100 person-years), might have been expected. CONCLUSIONS: This analysis indicates unrealized opportunities to reduce mortality in selected veterans with T2D and CAD via increased GLP-1RA and SGLT2i use.


Assuntos
Doenças Cardiovasculares , Diabetes Mellitus Tipo 2 , Inibidores do Transportador 2 de Sódio-Glicose , Diabetes Mellitus Tipo 2/tratamento farmacológico , Receptor do Peptídeo Semelhante ao Glucagon 1 , Glucose , Humanos , Hipoglicemiantes/uso terapêutico , Sódio , Inibidores do Transportador 2 de Sódio-Glicose/uso terapêutico , Saúde dos Veteranos
14.
Mol Microbiol ; 111(4): 965-980, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30636070

RESUMO

Cell division in most bacteria is directed by FtsZ, a conserved tubulin-like GTPase that assembles forming the cytokinetic Z-ring and constitutes a target for the discovery of new antibiotics. The developmental regulator MciZ, a 40-amino acid peptide endogenously produced during Bacillus subtilis sporulation, halts cytokinesis in the mother cell by inhibiting FtsZ. The crystal structure of a FtsZ:MciZ complex revealed that bound MciZ extends the C-terminal ß-sheet of FtsZ blocking its assembly interface. Here we demonstrate that exogenously added MciZ specifically inhibits B. subtilis cell division, sporulation and germination, and provide insight into MciZ molecular recognition by FtsZ from different bacteria. MciZ and FtsZ form a complex with sub-micromolar affinity, analyzed by analytical ultracentrifugation, laser biolayer interferometry and isothermal titration calorimetry. Synthetic MciZ analogs, carrying single amino acid substitutions impairing MciZ ß-strand formation or hydrogen bonding to FtsZ, show a gradual reduction in affinity that resembles their impaired activity in bacteria. Gene sequences encoding MciZ spread across genus Bacillus and synthetic MciZ slows down cell division in Bacillus species, including pathogenic Bacillus cereus and Bacillus anthracis. Moreover, B. subtilis MciZ is recognized by the homologous FtsZ from Staphylococcus aureus and inhibits division when it is expressed into S. aureus cells.


Assuntos
Bacillus subtilis/efeitos dos fármacos , Proteínas de Bactérias/antagonistas & inibidores , Divisão Celular/efeitos dos fármacos , Proteínas do Citoesqueleto/antagonistas & inibidores , Peptídeos/farmacologia , Substituição de Aminoácidos , Bacillus subtilis/genética , Proteínas de Bactérias/genética , Sítios de Ligação , Proteínas do Citoesqueleto/genética , Regulação Bacteriana da Expressão Gênica , Peptídeos/síntese química , Ligação Proteica , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/genética
15.
Small ; 16(50): e2005439, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33230936

RESUMO

Control of the metal-insulator phase transition is vital for emerging neuromorphic and memristive technologies. The ability to alter the electrically driven transition between volatile and non-volatile states is particularly important for quantum-materials-based emulation of neurons and synapses. The major challenge of this implementation is to understand and control the nanoscale mechanisms behind these two fundamental switching modalities. Here, in situ X-ray nanoimaging is used to follow the evolution of the nanostructure and disorder in the archetypal Mott insulator VO2 during an electrically driven transition. Our findings demonstrate selective and reversible stabilization of either the insulating or metallic phases achieved by manipulating the defect concentration. This mechanism enables us to alter the local switching response between volatile and persistent regimes and demonstrates a new possibility for nanoscale control of the resistive switching in Mott materials.

16.
Am J Pathol ; 189(11): 2311-2322, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31499027

RESUMO

Lactoferrin (LTF) is an iron-binding protein canonically known for its innate and adaptive immune functions. LTF may also act as a tumor suppressor with antiproliferative action. LTF is inactivated genetically or epigenetically in various cancers, and a CpG island spanning the transcriptional start site of LTF is hypermethylated in prostate cancer cell lines. We, therefore, hypothesized that LTF expression is silenced via CpG island hypermethylation in the early stages of prostate tumorigenesis carcinogenesis. Targeted methylation analysis was performed using a combination of methylated-DNA precipitation and methylation-sensitive restriction enzymes, and laser-capture microdissection followed by bisulfite sequencing on DNA isolated from prostate tissue samples, including both primary and metastatic disease. LTF mRNA in situ hybridization and LTF protein immunohistochemistry were also performed. We report that the LTF CpG island is frequently and densely methylated in high-grade prostatic intraepithelial neoplasia, primary prostate carcinoma, and metastases. We further report a decoupling of lactoferrin mRNA and protein expression, including in lesions where LTF mRNA has presumably been silenced via CpG island methylation. We conclude that LTF mRNA expression is silenced in prostate tumorigenesis via hypermethylation, supporting a role for LTF as a prostate cancer tumor suppressor gene. Likewise, the frequency at which the LTF CpG island is methylated across samples suggests it is an important and conserved step in prostate cancer initiation.


Assuntos
Adenocarcinoma , Carcinogênese/genética , Ilhas de CpG/genética , Metilação de DNA , Lactoferrina/genética , Neoplasias da Próstata , Adenocarcinoma/genética , Adenocarcinoma/metabolismo , Adenocarcinoma/patologia , Carcinogênese/metabolismo , Carcinogênese/patologia , Linhagem Celular Tumoral , Progressão da Doença , Regulação Neoplásica da Expressão Gênica , Genes Supressores de Tumor , Humanos , Lactoferrina/metabolismo , Masculino , Estadiamento de Neoplasias , Regiões Promotoras Genéticas , Neoplasias da Próstata/genética , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/patologia , RNA Mensageiro/metabolismo
17.
Catheter Cardiovasc Interv ; 95(3): 439-446, 2020 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-31816169

RESUMO

BACKGROUND: Femoropopliteal (FP) artery is one of the most anatomically challenging areas for sustained stent patency. The incidence of FP in-stent restenosis (ISR) is estimated at 50% at 24 months. Prior studies have shown that lesion debulking with laser atherectomy (LA) combined with drug coated balloon (DCB) have superior outcomes compared to LA + balloon angioplasty (BA) ISR, but there have not been studies evaluating 2-year outcomes. METHODS: This was a dual-center retrospective cohort study that compared patients with FP-ISR treated with LA + DCB versus LA + BA. Cox regression analysis was used to examine 2-year outcomes of target lesion revascularization (TLR) and the composite outcome of TLR or restenosis. Multivariable analysis was performed for clinical and statistically significant (in the univariate analysis) variables. RESULTS: One hundred and seventeen consecutive patients with Tosaka II (n = 32) and III (n = 85) ISR were analyzed. Sixty-six patients were treated with LA + DCB and 51 with LA + BA. The LA + DCB group had more lesions with moderate to severe calcification (58% vs. 13%; p < .0001). The LA + DCB group was more likely to be treated with the use of embolic protection devices (64% vs. 23%, p < .001) and cutting balloons (61% vs. 6%, p < .001). Bail-out stenting rates were lower in the LA + DCB group (32% vs. 57%, p = .008). LA + DCB was superior (HR: 0.57; 95% CI: 0.34-0.9, p = .027) for the composite outcome of 2-year TLR or restenosis. The 12-month KM estimates for freedom from TLR or restenosis were 66% in the LA + DCB group versus 46% in the LA + BA group. The 24-month KM estimates were 45% in the LA + DCB group versus 24% in the LA + BA group. CONCLUSIONS: The combination of DCB + LA was associated with decreased rates of bail-out stenting and improved 2-year TLR or restenosis rates. Randomized clinical trials examining the DCB + LA combination for FP-ISR are needed.


Assuntos
Angioplastia com Balão/instrumentação , Aterectomia , Materiais Revestidos Biocompatíveis , Procedimentos Endovasculares/instrumentação , Artéria Femoral/cirurgia , Terapia a Laser , Doença Arterial Periférica/terapia , Artéria Poplítea/cirurgia , Stents , Idoso , Idoso de 80 Anos ou mais , Angioplastia com Balão/efeitos adversos , Aterectomia/efeitos adversos , Constrição Patológica , Bases de Dados Factuais , Procedimentos Endovasculares/efeitos adversos , Feminino , Artéria Femoral/diagnóstico por imagem , Artéria Femoral/fisiopatologia , Humanos , Terapia a Laser/efeitos adversos , Masculino , Pessoa de Meia-Idade , Doença Arterial Periférica/diagnóstico por imagem , Doença Arterial Periférica/fisiopatologia , Artéria Poplítea/diagnóstico por imagem , Artéria Poplítea/fisiopatologia , Recidiva , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento , Estados Unidos , Grau de Desobstrução Vascular
18.
J Endovasc Ther ; 27(3): 492-501, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32364000

RESUMO

Purpose: To examine whether the combination of orbital atherectomy (OA) and drug-coated balloons (DCB) can lead to superior procedural and 2-year outcomes compared with DCB only in heavily calcified femoropopliteal (FP) lesions. Materials and Methods: A retrospective chart review was conducted to identify patients treated with DCB only or OA+DCB for de novo FP lesions at a single center over a 4-year period (2014-2017). In the observation period, 113 patients met the inclusion criteria: 63 treated with DCB only (mean age 69.0±8.6 years; 62 men) vs 50 treated with OA+DCB (mean age 70.3±7.1 years; 48 men). The OA+DCB group had higher calcification rates (78% with severe calcification vs 37% in the DCB only group). Propensity score matching (PSM) was used to adjust for baseline differences between the 2 groups. Cox regression analysis was used to compare the follow-up outcomes between lesions treated with OA+DCB vs DCB only. Results: No difference in procedural complications or success was found. After PSM adjustment, the OA+DCB group was associated with lower bailout stenting rates (39.4% vs 66.7% in the DCB only group; p=0.026). The 2 groups had similar long-term outcomes, although the OA+DCB arm had a trend toward reduced TLR rates that did not reach statistical significance. The Kaplan-Meier estimates for 2-year freedom from TLR were 76.1% for the OA+DCB group vs 55.5% for the DCB only group (p=0.109). Conclusion: OA+DCB is a safe and effective combination for the treatment of calcified FP lesions. The combined therapy decreased the bailout stenting rates in the adjusted analysis. Larger cohorts and randomized trials are needed to examine OA efficacy in FP lesions.


Assuntos
Angioplastia com Balão/instrumentação , Aterectomia , Materiais Revestidos Biocompatíveis , Artéria Femoral , Doença Arterial Periférica/terapia , Artéria Poplítea , Dispositivos de Acesso Vascular , Calcificação Vascular/terapia , Idoso , Angioplastia com Balão/efeitos adversos , Terapia Combinada , Feminino , Artéria Femoral/diagnóstico por imagem , Artéria Femoral/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Doença Arterial Periférica/diagnóstico por imagem , Doença Arterial Periférica/fisiopatologia , Artéria Poplítea/diagnóstico por imagem , Artéria Poplítea/fisiopatologia , Estudos Retrospectivos , Índice de Gravidade de Doença , Fatores de Tempo , Resultado do Tratamento , Calcificação Vascular/diagnóstico por imagem , Calcificação Vascular/fisiopatologia , Grau de Desobstrução Vascular
19.
Salud Publica Mex ; 62(4): 424-431, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32549084

RESUMO

OBJECTIVE: To compare the efficacy of three modern larvicides with the organophosphate temephos for control of Aedes aegypti in water tanks in Chiapas. MATERIALS AND METHODS: Trials were performed to compare the efficacy of pyriproxyfen, novaluron, two formulations of spinosad (granules and tablets) and temephos in oviposition traps and domestic water tanks. RESULTS: Pyriproxyfen and temephos provided 2-3 weeks of complete control of larvae in oviposition traps, whereas spinosad granules and novaluron provided 7-12 weeks of control. Treatment of water tanks resulted in a significant reduction in oviposition by Ae. aegypti in houses (p<0.001). Higher numbers of larvae were present in temephos and pyriproxyfen-treated water tanks compared to novaluron and spinosad tablet treatments during most of the study. CONCLUSIONS: Spinosad formulations and novaluron were effective larvicides in this region. The poor performance of temephos may be indicative of reduced susceptibility in Ae. aegypti populations in Chiapas.


OBJETIVO: Comparar la eficacia de tres larvicidas modernos para el control de Aedes aegypti en tanques de agua doméstica en Chiapas. MATERIAL Y MÉTODOS: Se comparó la eficacia de piriproxifeno, novalurón, dos formulaciones de spinosad (gránulos y tabletas) y temefos en ovitrampas y tanques domésticos de agua. RESULTADOS: El piriproxifeno y el temefos proporcionaron de 2 a 3 semanas de control de larvas en ovitrampas, mientras que los gránulos de spinosad y novaluron proporcionaron de 7 a12 semanas. Los tanques de agua tratados produjeron una reducción significativa en la oviposición por Ae. aegypti en las casas (p<0.001). Se encontró gran cantidad de larvas en los tanques tratados con temefos y piriproxifeno en comparación con los tratados con novaluron y tabletas de spinosad durante la mayor parte del estudio. CONCLUSIONES: Las formulaciones de spinosad en tabletas y novaluron fueron larvicidas efectivos en esta región. El bajo desempeño de temefos puede indicar una susceptibilidad reducida en poblaciones de Ae. aegypti en Chiapas.


Assuntos
Aedes , Inseticidas , Macrolídeos , Compostos de Fenilureia , Piridinas , Temefós , Aedes/anatomia & histologia , Animais , Combinação de Medicamentos , Feminino , Habitação , Larva , México , Controle de Mosquitos/métodos , Oviposição , Água/parasitologia
20.
J Antimicrob Chemother ; 74(9): 2617-2625, 2019 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-31127270

RESUMO

OBJECTIVES: To investigate the mechanism of action at the molecular level of pepR, a multifunctional peptide derived from the Dengue virus capsid protein, against Staphylococcus aureus biofilms. METHODS: Biofilm mass, metabolic activity and viability were quantified using conventional microbiology techniques, while fluorescence imaging methods, including a real-time calcein release assay, were employed to investigate the kinetics of pepR activity at different biofilm depths. RESULTS: Using flow cytometry-based assays, we showed that pepR is able to prevent staphylococcal biofilm formation due to a fast killing of planktonic bacteria, which in turn resulted from a peptide-induced increase in the permeability of the bacterial membranes. The activity of pepR against pre-formed biofilms was evaluated through the application of a quantitative live/dead confocal laser scanning microscopy (CLSM) assay. The results show that the bactericidal activity of pepR on pre-formed biofilms is dose and depth dependent. A CLSM-based assay of calcein release from biofilm-embedded bacteria was further developed to indirectly assess the diffusion and membrane permeabilization properties of pepR throughout the biofilm. A slower diffusion and delayed activity of the peptide at deeper layers of the biofilm were quantified. CONCLUSIONS: Overall, our results show that the activity of pepR on pre-formed biofilms is controlled by its diffusion along the biofilm layers, an effect that can be counteracted by an additional administration of peptide. Our study sheds new light on the antibiofilm mechanism of action of antimicrobial peptides, particularly the importance of their diffusion properties through the biofilm matrix on their activity.


Assuntos
Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Biofilmes/efeitos dos fármacos , Vírus da Dengue/genética , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus/efeitos dos fármacos , Proteínas do Capsídeo/genética , Infecções Estafilocócicas/microbiologia
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