Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 759
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Proc Natl Acad Sci U S A ; 120(20): e2208673120, 2023 05 16.
Artigo em Inglês | MEDLINE | ID: mdl-37155900

RESUMO

The immune deficiency (IMD) pathway directs host defense in arthropods upon bacterial infection. In Pancrustacea, peptidoglycan recognition proteins sense microbial moieties and initiate nuclear factor-κB-driven immune responses. Proteins that elicit the IMD pathway in non-insect arthropods remain elusive. Here, we show that an Ixodes scapularis homolog of croquemort (Crq), a CD36-like protein, promotes activation of the tick IMD pathway. Crq exhibits plasma membrane localization and binds the lipid agonist 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol. Crq regulates the IMD and jun N-terminal kinase signaling cascades and limits the acquisition of the Lyme disease spirochete B. burgdorferi. Additionally, nymphs silenced for crq display impaired feeding and delayed molting to adulthood due to a deficiency in ecdysteroid synthesis. Collectively, we establish a distinct mechanism for arthropod immunity outside of insects and crustaceans.


Assuntos
Artrópodes , Infecções Bacterianas , Borrelia burgdorferi , Ixodes , Doença de Lyme , Animais , Ixodes/microbiologia , Borrelia burgdorferi/genética , NF-kappa B , Doença de Lyme/microbiologia
2.
J Biomol NMR ; 2024 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-38856928

RESUMO

Deuterium (2H) spin relaxation of 13CH2D methyl groups has been widely applied to investigate picosecond-to-nanosecond conformational dynamics in proteins by solution-state NMR spectroscopy. The B0 dependence of the 2H spin relaxation rates is represented by a linear relationship between the spectral density function at three discrete frequencies J(0), J(ωD) and J(2ωD). In this study, the linear relation between 2H relaxation rates at B0 fields separated by a factor of two and the interpolation of rates at intermediate frequencies are combined for a more robust approach for spectral density mapping. The general usefulness of the approach is demonstrated on a fractionally deuterated (55%) and alternate 13C-12C labeled sample of E. coli RNase H. Deuterium relaxation rate constants (R1, R1ρ, RQ, RAP) were measured for 57 well-resolved 13CH2D moieties in RNase H at 1H frequencies of 475 MHz, 500 MHz, 900 MHz, and 950 MHz. The spectral density mapping of the 475/950 MHz data combination was performed independently and jointly to validate the expected relationship between data recorded at B0 fields separated by a factor of two. The final analysis was performed by jointly analyzing 475/950 MHz rates with 700 MHz rates interpolated from 500/900 MHz data to yield six J(ωD) values for each methyl peak. The J(ω) profile for each peak was fit to the original (τM, Sf2, τf) or extended model-free function (τM, Sf2, Ss2, τf, τs) to obtain optimized dynamic parameters.

3.
J Chem Inf Model ; 64(8): 3477-3487, 2024 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-38605537

RESUMO

Allostery is an essential biological phenomenon in which perturbation at one site in a biomolecule elicits a functional response at a distal location(s). It is integral to biological processes, such as cellular signaling, metabolism, and transcription regulation. Understanding allostery is also crucial for rational drug discovery. In this work, we focus on an allosteric S100B protein that belongs to the S100 class of EF-hand Ca2+-binding proteins. The Ca2+-binding affinity of S100B is modulated allosterically by TRTK-12 peptide binding 25 Å away from the Ca2+-binding site. We investigated S100B allostery by carrying out nuclear magnetic resonance (NMR) measurements along with microsecond-long molecular dynamics (MD) simulations on S100B/Ca2+ with/without TRTK-12 at different NaCl salt concentrations. NMR HSQC results show that TRTK-12 reorganizes how S100B/Ca2+ responds to different salt concentrations at both orthosteric and allosteric sites. The MD data suggest that TRTK-12 breaks the dynamic aromatic and hydrogen-bond interactions (not observed in X-ray crystallographic structures) between the hinge/helix and Ca2+-binding EF-hand loop of the two subunits in the homodimeric protein. This triggers rearrangement in the protein network architectures and leads to allosteric communication. Finally, computational studies of S100B at distinct ionic strengths suggest that ligand-bound species are more robust to the changing environment relative to the S100B/Ca2+ complex.


Assuntos
Proteína de Capeamento de Actina CapZ , Simulação de Dinâmica Molecular , Subunidade beta da Proteína Ligante de Cálcio S100 , Regulação Alostérica , Subunidade beta da Proteína Ligante de Cálcio S100/química , Subunidade beta da Proteína Ligante de Cálcio S100/metabolismo , Cálcio/metabolismo , Humanos , Transdução de Sinais , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Oligopeptídeos/química , Oligopeptídeos/metabolismo , Ligação Proteica , Conformação Proteica
4.
Ann Hum Biol ; 51(1): 2298474, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38293777

RESUMO

BACKGROUND: Lack of paediatric reference data limits the utility of handgrip strength as a measure of fitness and well-being. AIM: To develop paediatric handgrip reference curves and evaluate associations with body size and composition and race/ethnicity group. SUBJECTS AND METHODS: Handgrip, body size and composition data were obtained from National Health and Nutrition Examination Survey 2011-2014 participants aged 6-20 years. Densitometry-derived fat and appendicular lean soft tissue mass index Z-scores (FMIZ, ALSTMIZ) were generated in participants >8 years. Dominant and non-dominant handgrip reference curves were created using the LMS method. Analyses included sample weights to produce nationally representative estimates. RESULTS: Differences in handgrip strength according to hand dominance increased with age. Handgrip strength was associated with height and arm length Z-scores (R = 0.42 to 0.47) and ALSTMIZ (R = 0.54). Handgrip strength was higher in the non-Hispanic Black group and lower in the Mexican American compared to non-Hispanic White group. Group differences were attenuated when adjusted for height, arm length or ALSTMIZ. CONCLUSION: Paediatric handgrip reference curves were generated from which individual Z-scores can be calculated separately for dominant versus non-dominant hand and adjusted for body size. Association with ALSTMIZ suggests handgrip Z-score may be used as a measure of functional body composition.


Assuntos
Composição Corporal , Força da Mão , Humanos , Criança , Inquéritos Nutricionais , Tamanho Corporal , Valores de Referência
5.
Wilderness Environ Med ; 35(1_suppl): 20S-44S, 2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-37945433

RESUMO

To provide guidance to the general public, clinicians, and avalanche professionals about best practices, the Wilderness Medical Society convened an expert panel to revise the evidence-based guidelines for the prevention, rescue, and resuscitation of avalanche and nonavalanche snow burial victims. The original panel authored the Wilderness Medical Society Practice Guidelines for Prevention and Management of Avalanche and Nonavalanche Snow Burial Accidents in 2017. A second panel was convened to update these guidelines and make recommendations based on quality of supporting evidence.


Assuntos
Avalanche , Neve , Acidentes , Sepultamento , Sociedades Médicas , Humanos
6.
Wilderness Environ Med ; 35(2): 198-218, 2024 06.
Artigo em Inglês | MEDLINE | ID: mdl-38651342

RESUMO

The Wilderness Medical Society (WMS) convened an expert panel to develop evidence-based guidelines for the management of pain in austere environments. Recommendations are graded based on the quality of supporting evidence as defined by criteria put forth by the American College of Chest Physicians. This is an update of the 2014 version of the "WMS Practice Guidelines for the Treatment of Acute Pain in Remote Environments" published in Wilderness & Environmental Medicine 2014; 25:41-49.


Assuntos
Dor Aguda , Manejo da Dor , Sociedades Médicas , Medicina Selvagem , Medicina Selvagem/normas , Medicina Selvagem/métodos , Humanos , Dor Aguda/terapia , Dor Aguda/tratamento farmacológico , Manejo da Dor/métodos , Manejo da Dor/normas , Região de Recursos Limitados
7.
Clin Infect Dis ; 76(3): e34-e41, 2023 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-35997795

RESUMO

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic had a considerable impact on US healthcare systems, straining hospital resources, staff, and operations. However, a comprehensive assessment of the impact on healthcare-associated infections (HAIs) across different hospitals with varying level of infectious disease (ID) physician expertise, resources, and infrastructure is lacking. METHODS: This retrospective longitudinal multicenter cohort study included central-line-associated bloodstream infections (CLABSIs), catheter-associated urinary tract infections (CAUTIs), Clostridioides difficile infections (CDIs), and ventilator-associated events (VAEs) from 53 hospitals (academic and community) in Southeastern United States from 1 January 2018 to 31 March 2021. Segmented negative binomial regression generalized estimating equations models estimated changes in monthly incidence rates in the baseline (01/2018-02/2020) compared to the pandemic period (03/2020-03/2021, further divided into three pandemic phases). RESULTS: CLABSIs and VAEs increased by 24% and 34%, respectively, during the pandemic period. VAEs increased in all phases of the pandemic, while CLABSIs increased in later phases of the pandemic. CDI trend increased by 4.2% per month in the pandemic period. On stratifying the analysis by hospital characteristics, the impact of the pandemic on healthcare-associated infections was more significant in smaller sized and community hospitals. CAUTIs did not change significantly during the pandemic across all hospital types. CONCLUSIONS: CLABSIs, VAEs, and CDIs increased significantly during the pandemic, especially in smaller community hospitals, most of which lack ID physician expertise. Future efforts should focus on better understanding challenges faced by community hospitals, strengthening the infection prevention infrastructure, and expanding the ID workforce, particularly to community hospitals.


Assuntos
COVID-19 , Infecções Relacionadas a Cateter , Infecções por Clostridium , Doenças Transmissíveis , Infecção Hospitalar , Infecções Urinárias , Humanos , Infecções Relacionadas a Cateter/prevenção & controle , Hospitais Comunitários , Estudos Retrospectivos , Estudos de Coortes , Pandemias , COVID-19/epidemiologia , COVID-19/complicações , Infecção Hospitalar/prevenção & controle , Doenças Transmissíveis/epidemiologia , Infecções Urinárias/epidemiologia , Infecções por Clostridium/epidemiologia
8.
J Clin Microbiol ; 61(12): e0073123, 2023 12 19.
Artigo em Inglês | MEDLINE | ID: mdl-38014985

RESUMO

IMPORTANCE: Despite the relatively high mortality and the difficulty in diagnosis, nearly one-third of patients hospitalized with a documented diagnosis of encephalitis did not undergo a lumbar puncture (LP). When an LP was performed, pathogen-specific testing was greatly underutilized. Infectious etiologies were most common, but over 40% of cases were idiopathic at discharge. These findings suggest that there is a substantial opportunity to improve the quality of care through more accurate and timely diagnosis.


Assuntos
Líquidos Corporais , Encefalite , Humanos , North Carolina/epidemiologia , Encefalite/diagnóstico , Encefalite/epidemiologia , Punção Espinal
9.
Crit Care Med ; 51(11): 1570-1586, 2023 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-37902340

RESUMO

RATIONALE: Fever is frequently an early indicator of infection and often requires rigorous diagnostic evaluation. OBJECTIVES: This is an update of the 2008 Infectious Diseases Society of America and Society (IDSA) and Society of Critical Care Medicine (SCCM) guideline for the evaluation of new-onset fever in adult ICU patients without severe immunocompromise, now using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology. PANEL DESIGN: The SCCM and IDSA convened a taskforce to update the 2008 version of the guideline for the evaluation of new fever in critically ill adult patients, which included expert clinicians as well as methodologists from the Guidelines in Intensive Care, Development and Evaluation Group. The guidelines committee consisted of 12 experts in critical care, infectious diseases, clinical microbiology, organ transplantation, public health, clinical research, and health policy and administration. All task force members followed all conflict-of-interest procedures as documented in the American College of Critical Care Medicine/SCCM Standard Operating Procedures Manual and the IDSA. There was no industry input or funding to produce this guideline. METHODS: We conducted a systematic review for each population, intervention, comparison, and outcomes question to identify the best available evidence, statistically summarized the evidence, and then assessed the quality of evidence using the GRADE approach. We used the evidence-to-decision framework to formulate recommendations as strong or weak or as best-practice statements. RESULTS: The panel issued 12 recommendations and 9 best practice statements. The panel recommended using central temperature monitoring methods, including thermistors for pulmonary artery catheters, bladder catheters, or esophageal balloon thermistors when these devices are in place or accurate temperature measurements are critical for diagnosis and management. For patients without these devices in place, oral or rectal temperatures over other temperature measurement methods that are less reliable such as axillary or tympanic membrane temperatures, noninvasive temporal artery thermometers, or chemical dot thermometers were recommended. Imaging studies including ultrasonography were recommended in addition to microbiological evaluation using rapid diagnostic testing strategies. Biomarkers were recommended to assist in guiding the discontinuation of antimicrobial therapy. All recommendations issued were weak based on the quality of data. CONCLUSIONS: The guidelines panel was able to formulate several recommendations for the evaluation of new fever in a critically ill adult patient, acknowledging that most recommendations were based on weak evidence. This highlights the need for the rapid advancement of research in all aspects of this issue-including better noninvasive methods to measure core body temperature, the use of diagnostic imaging, advances in microbiology including molecular testing, and the use of biomarkers.


Assuntos
Doenças Transmissíveis , Estado Terminal , Humanos , Adulto , Estado Terminal/terapia , Febre/diagnóstico , Cuidados Críticos/métodos , Unidades de Terapia Intensiva , Biomarcadores
10.
Circ Res ; 129(12): e215-e233, 2021 12 03.
Artigo em Inglês | MEDLINE | ID: mdl-34702049

RESUMO

RATIONALE: Vascular smooth muscle cells (SMCs) exhibit remarkable plasticity and can undergo dedifferentiation upon pathological stimuli associated with disease and interventions. OBJECTIVE: Although epigenetic changes are critical in SMC phenotype switching, a fundamental regulator that governs the epigenetic machineries regulating the fate of SMC phenotype has not been elucidated. METHODS AND RESULTS: Using SMCs, mouse models, and human atherosclerosis specimens, we found that FAK (focal adhesion kinase) activation elicits SMC dedifferentiation by stabilizing DNMT3A (DNA methyltransferase 3A). FAK in SMCs is activated in the cytoplasm upon serum stimulation in vitro or vessel injury and active FAK prevents DNMT3A from nuclear FAK-mediated degradation. However, pharmacological or genetic FAK catalytic inhibition forced FAK nuclear localization, which reduced DNMT3A protein via enhanced ubiquitination and proteasomal degradation. Reduced DNMT3A protein led to DNA hypomethylation in contractile gene promoters, which increased SMC contractile protein expression. RNA-sequencing identified SMC contractile genes as a foremost upregulated group by FAK inhibition from injured femoral artery samples compared with vehicle group. DNMT3A knockdown in injured arteries reduced DNA methylation and enhanced contractile gene expression supports the notion that nuclear FAK-mediated DNMT3A degradation via E3 ligase TRAF6 (TNF [tumor necrosis factor] receptor-associated factor 6) drives differentiation of SMCs. Furthermore, we observed that SMCs of human atherosclerotic lesions exhibited decreased nuclear FAK, which was associated with increased DNMT3A levels and decreased contractile gene expression. CONCLUSIONS: This study reveals that nuclear FAK induced by FAK catalytic inhibition specifically suppresses DNMT3A expression in injured vessels resulting in maintaining SMC differentiation by promoting the contractile gene expression. Thus, FAK inhibitors may provide a new treatment option to block SMC phenotypic switching during vascular remodeling and atherosclerosis.


Assuntos
Desdiferenciação Celular , Proteínas Contráteis/genética , Metilação de DNA , Quinase 1 de Adesão Focal/metabolismo , Músculo Liso Vascular/metabolismo , Miócitos de Músculo Liso/metabolismo , Animais , Células Cultivadas , Proteínas Contráteis/metabolismo , DNA Metiltransferase 3A/genética , DNA Metiltransferase 3A/metabolismo , Quinase 1 de Adesão Focal/genética , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Músculo Liso Vascular/citologia , Miócitos de Músculo Liso/citologia , Miócitos de Músculo Liso/fisiologia , Proteólise , Ubiquitinação , Regulação para Cima
11.
Infection ; 51(6): 1759-1765, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37501013

RESUMO

PURPOSE: Fever is a common cause for hospitalization among the pediatric population. The spectrum of causative agents is diverse. Human herpesvirus 6 (HHV-6) is a ubiquitous virus that often causes hospitalization of children in western countries. Previously, we investigated the cause of fever of 600 febrile hospitalized children in Gabon, and in 91 cases the causative pathogen was not determined. In this study, we assessed HHV-6 infection as potential cause of hospitalization in this group. METHODS: Blood samples were assessed for HHV-6 using real-time quantitative PCR. Three groups were investigated: (1) group of interest: 91 hospitalized children with febrile illness without a diagnosed causing pathogen; (2) hospitalized control: 91 age-matched children hospitalized with febrile illness with a potentially disease-causing pathogen identified; both groups were recruited at the Albert Schweitzer Hospital in Lambaréné, Gabon and (3) healthy control: 91 healthy children from the same area. RESULTS: Samples from 273 children were assessed. Age range was two months to 14 years, median (IQR) age was 36 (12-71) months; 52% were female. HHV-6 was detected in 64% (58/91), 41% (37/91), and 26% (24/91) of the samples from groups 1, 2, and 3, respectively; with statistically significant odds of being infected with HHV-6 in group 1 (OR = 4.62, 95% CI [2.46, 8.90]). Only HHV-6B was detected. CONCLUSIONS: Although tropical diseases account for a large proportion of children's hospitalizations, considering common childhood diseases such as HHV-6 when diagnosing febrile illnesses in pediatric populations in tropical countries is of importance.


Assuntos
Infecções por Herpesviridae , Herpesvirus Humano 6 , Criança , Humanos , Feminino , Lactente , Pré-Escolar , Masculino , Herpesvirus Humano 6/genética , Criança Hospitalizada , Gabão/epidemiologia , Febre/epidemiologia , Reação em Cadeia da Polimerase em Tempo Real , Infecções por Herpesviridae/complicações , Infecções por Herpesviridae/diagnóstico
12.
Pediatr Blood Cancer ; : e30419, 2023 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-37194624

RESUMO

Complex lymphatic anomalies are debilitating conditions characterized by aberrant development of the lymphatic vasculature (lymphangiogenesis). Diagnosis is typically made by history, examination, radiology, and histologic findings. However, there is significant overlap between conditions, making accurate diagnosis difficult. Recently, genetic analysis has been offered as an additional diagnostic modality. Here, we describe four cases of complex lymphatic anomalies, all with PIK3CA variants but with varying clinical phenotypes. Identification of PIK3CA resulted in transition to a targeted inhibitor, alpelisib. These cases highlight the genetic overlap between phenotypically diverse lymphatic anomalies.

13.
Bioorg Chem ; 139: 106700, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37392559

RESUMO

Galeterone, 3ß-(hydroxy)-17-(1H-benzimidazole-1-yl)androsta-5,16-diene (Gal, 1) and VNPP433-3ß, 3ß-(1H-imidazole-1-yl-17-(1H-benzimidazole-1-yl)androsta-5,16-diene (2) are potent molecular glue degrader modulators of AR/AR-V7 and Mnk1/2-eIF4E signaling pathways, and are promising Phase 3 and Phase 1 drug candidates, respectively. Because appropriate salts can be utilized to create new chemical entities with enhanced aqueous solubility, in vivo pharmacokinetics, and enhanced in vitro and in vivo efficacies, the monohydrochloride salt of Gal (3) and the mono- and di-hydrochlorides salts of compound 2, compounds 4 and 5, respectively, were synthesized. The salts were characterized using 1H NMR, 13C NMR and HRMS analyses. Compound 3 displayed enhanced in vitro antiproliferative activity (7.4-fold) against three prostate cancer cell lines but surprisingly decreased plasma exposure in the pharmacokinetics study. The antiproliferative activities of the compound 2 salts (4 and 5) were equivalent to that of compound 2, but their oral pharmacokinetic profiles were significantly enhanced. Finally, and most importantly, oral administration of the parent compounds (1 and 2) and their corresponding salts (3, 4 and 5) caused dose-dependent potent inhibition/regression of aggressive and difficult-to-treat CWR22Rv1 tumor xenografts growth, with no apparent host toxicities and were highly more efficacious than the blockbuster FDA-approved prostate cancer drugs, Enzalutamide (Xtandi) and Docetaxel (Taxotere). Thus, the HCl salts of Gal (3) and VNPP433-3ß (4 and 5) are excellent orally bioavailable candidates for clinical development.


Assuntos
Neoplasias de Próstata Resistentes à Castração , Masculino , Humanos , Animais , Camundongos , Docetaxel/farmacologia , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Xenoenxertos , Sais , Receptores Androgênicos/metabolismo , Nitrilas , Benzimidazóis/uso terapêutico , Linhagem Celular Tumoral
14.
Nucleic Acids Res ; 49(3): 1235-1246, 2021 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-33398344

RESUMO

We have identified chemical probes that simultaneously inhibit cancer cell progression and an immune checkpoint. Using the computational Site Identification by Ligand Competitive Saturation (SILCS) technology, structural biology and cell-based assays, we identify small molecules that directly and selectively bind to the RNA Recognition Motif (RRM) of hnRNP A18, a regulator of protein translation in cancer cells. hnRNP A18 recognizes a specific RNA signature motif in the 3'UTR of transcripts associated with cancer cell progression (Trx, VEGF, RPA) and, as shown here, a tumor immune checkpoint (CTLA-4). Post-transcriptional regulation of immune checkpoints is a potential therapeutic strategy that remains to be exploited. The probes target hnRNP A18 RRM in vitro and in cells as evaluated by cellular target engagement. As single agents, the probes specifically disrupt hnRNP A18-RNA interactions, downregulate Trx and CTLA-4 protein levels and inhibit proliferation of several cancer cell lines without affecting the viability of normal epithelial cells. These first-in-class chemical probes will greatly facilitate the elucidation of the underexplored biological function of RNA Binding Proteins (RBPs) in cancer cells, including their effects on proliferation and immune checkpoint activation.


Assuntos
Antineoplásicos/farmacologia , Proteínas de Ligação a RNA/antagonistas & inibidores , Animais , Antineoplásicos/uso terapêutico , Antígeno CTLA-4/genética , Antígeno CTLA-4/metabolismo , Linhagem Celular Tumoral , Humanos , Ligantes , Camundongos , Neoplasias/tratamento farmacológico , Neoplasias/genética , Neoplasias/metabolismo , Ressonância Magnética Nuclear Biomolecular , Biossíntese de Proteínas , RNA/metabolismo , Motivo de Reconhecimento de RNA , Proteínas de Ligação a RNA/química , Proteínas de Ligação a RNA/metabolismo
15.
Proc Natl Acad Sci U S A ; 117(2): 1049-1058, 2020 01 14.
Artigo em Inglês | MEDLINE | ID: mdl-31896582

RESUMO

Targeting Clostridium difficile infection is challenging because treatment options are limited, and high recurrence rates are common. One reason for this is that hypervirulent C. difficile strains often have a binary toxin termed the C. difficile toxin, in addition to the enterotoxins TsdA and TsdB. The C. difficile toxin has an enzymatic component, termed CDTa, and a pore-forming or delivery subunit termed CDTb. CDTb was characterized here using a combination of single-particle cryoelectron microscopy, X-ray crystallography, NMR, and other biophysical methods. In the absence of CDTa, 2 di-heptamer structures for activated CDTb (1.0 MDa) were solved at atomic resolution, including a symmetric (SymCDTb; 3.14 Å) and an asymmetric form (AsymCDTb; 2.84 Å). Roles played by 2 receptor-binding domains of activated CDTb were of particular interest since the receptor-binding domain 1 lacks sequence homology to any other known toxin, and the receptor-binding domain 2 is completely absent in other well-studied heptameric toxins (i.e., anthrax). For AsymCDTb, a Ca2+ binding site was discovered in the first receptor-binding domain that is important for its stability, and the second receptor-binding domain was found to be critical for host cell toxicity and the di-heptamer fold for both forms of activated CDTb. Together, these studies represent a starting point for developing structure-based drug-design strategies to target the most severe strains of C. difficile.


Assuntos
ADP Ribose Transferases/química , ADP Ribose Transferases/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Toxinas Bacterianas/química , Toxinas Bacterianas/metabolismo , Clostridioides difficile/metabolismo , Enterotoxinas/química , Enterotoxinas/metabolismo , ADP Ribose Transferases/genética , Animais , Proteínas de Bactérias/genética , Sítios de Ligação , Fenômenos Biofísicos , Chlorocebus aethiops , Microscopia Crioeletrônica , Cristalografia por Raios X , Modelos Moleculares , Ressonância Magnética Nuclear Biomolecular , Conformação Proteica , Domínios Proteicos , Células Vero
16.
J Infect Dis ; 226(Suppl 4): S456-S462, 2022 10 21.
Artigo em Inglês | MEDLINE | ID: mdl-36265849

RESUMO

The United States varicella vaccination program has successfully reduced varicella incidence and hospitalizations by ≥90%, consequently reducing the risk of nosocomial exposures. However, patients and healthcare personnel (HCP) continue to introduce varicella zoster virus (VZV) into healthcare settings. Herpes zoster (HZ) is less contagious than varicella, but it can also result in exposures. Unrecognized varicella and HZ may lead to extensive contact investigations, control efforts, and HCP furloughs that result in significant disruption of healthcare activities as well as substantial costs. Robust occupational health and infection prevention programs that ensure healthcare personnel immunity and prompt recognition and isolation of patients with varicella or HZ will lower the risk of VZV transmission and reduce or eliminate the need to furlough exposed HCP and associated costs.


Assuntos
Varicela , Infecção Hospitalar , Herpes Zoster , Humanos , Estados Unidos/epidemiologia , Varicela/epidemiologia , Varicela/prevenção & controle , Herpesvirus Humano 3 , Infecção Hospitalar/epidemiologia , Infecção Hospitalar/prevenção & controle , Herpes Zoster/epidemiologia , Herpes Zoster/prevenção & controle , Vacinação , Vacina contra Varicela
17.
Clin Infect Dis ; 75(1): e307-e309, 2022 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-35023553

RESUMO

We assessed environmental contamination of inpatient rooms housing coronavirus disease 2019 (COVID-19) patients in a dedicated COVID-19 unit. Contamination with severe acute respiratory syndrome coronavirus 2 was found on 5.5% (19/347) of surfaces via reverse transcriptase polymerase chain reaction and 0.3% (1/347) of surfaces via cell culture. Environmental contamination is uncommon in hospitals rooms; RNA presence is not a specific indicator of infectious virus.


Assuntos
COVID-19 , SARS-CoV-2 , Técnicas de Cultura , Poluição Ambiental/análise , Hospitais , Humanos , RNA Viral
18.
Clin Infect Dis ; 74(4): 648-656, 2022 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-34017999

RESUMO

BACKGROUND: Shedding of Clostridioides difficile spores from infected individuals contaminates the hospital environment and contributes to infection transmission. We assessed whether antibiotic selection affects C. difficile shedding and contamination of the hospital environment. METHODS: In this prospective, unblinded, randomized controlled trial of hospitalized adults with C. difficile infection, patients were randomized 1:1:1 to receive fidaxomicin, oral vancomycin, or metronidazole. The primary outcome was change in environmental contamination rate during treatment. Secondary outcomes included stool shedding, total burden of contamination, and molecular relatedness of stool versus environmental C. difficile isolates. RESULTS: Of 33 patients enrolled, 31 (94%) completed the study. Fidaxomicin (-0.36 log10 colony-forming units [CFUs]/d [95% confidence interval (CI), -.52 to -.19]; P < .01) and vancomycin (-0.17 log10 CFUs/d [-.34 to -.01]; P = .05) were associated with more rapid decline in C. difficile shedding than metronidazole (-0.01 log10 CFUs/d [95% CI, -.10 to .08). Both vancomycin (6.3% [95% CI, 4.7-8.3) and fidaxomicin (13.1% [10.7-15.9]) were associated with lower rates of environmental contamination than metronidazole (21.4% [18.0-25.2]). With specific modeling of within-subject change over time, fidaxomicin (adjusted odds ratio, 0.83 [95% CI, .70-.99]; P = .04) was associated with more rapid decline in environmental contamination than vancomycin or metronidazole. Overall, 207 of 233 environmental C. difficile isolates (88.8%) matched patient stool isolates by ribotyping, without significant difference by treatment. CONCLUSIONS: Fidaxomicin, and to a lesser extent vancomycin, reduces C. difficile shedding and contamination of the hospital environment relative to metronidazole. Treatment choice may play a role in reducing healthcare-associated C. difficile transmission. CLINICAL TRIALS REGISTRATION: NCT02057198.


Assuntos
Clostridioides difficile , Infecções por Clostridium , Adulto , Aminoglicosídeos/farmacologia , Aminoglicosídeos/uso terapêutico , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Clostridioides , Infecções por Clostridium/tratamento farmacológico , Fidaxomicina/uso terapêutico , Humanos , Metronidazol/farmacologia , Metronidazol/uso terapêutico , Estudos Prospectivos , Vancomicina/farmacologia , Vancomicina/uso terapêutico
19.
Kidney Int ; 102(4): 894-903, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35752324

RESUMO

Azithromycin is an antibiotic with QT-prolonging potential commonly prescribed to individuals receiving hemodialysis. Hemodialysis patients have a high prevalence of clinical conditions, such as structural heart disease, that can enhance the pro-arrhythmic effects azithromycin, but were excluded from prior investigations evaluating the cardiac safety of azithromycin. Using data from the United States Renal Data System (2007-2017), we conducted two cohort studies to examine the cardiac safety of azithromycin relative to amoxicillin-based antibiotics (amoxicillin, amoxicillin/clavulanic acid) and levofloxacin (a fluoroquinolone antibiotic known to prolong the QT-interval) in the hemodialysis population. The primary outcome was five-day sudden cardiac death. Using inverse probability of treatment weighted survival models, we estimated hazard ratios, risk differences, and 95% confidence intervals. The azithromycin vs. amoxicillin-based antibiotic cohort included 282,899 patients and 725,431 treatment episodes (381,306 azithromycin and 344,125 amoxicillin-based episodes). Azithromycin vs. amoxicillin-based antibiotic treatment was associated with higher relative and absolute risks of sudden cardiac death, weighted hazard ratio of 1.70 (95% Confidence Interval, 1.36 to 2.11) and weighted risk difference per 100,000 treatment episodes of 25.0 (15.5 to 36.5). The azithromycin vs. levofloxacin cohort included 245,143 patients and 554,557 treatment episodes (387,382 azithromycin and 167,175 levofloxacin episodes). Azithromycin vs. levofloxacin treatment was associated with lower relative and absolute risks of sudden cardiac death, weighted hazard ratio of 0.79 (0.64 to 0.96) and weighted risk difference per 100,000 treatment episodes of -18.9 (-35.5 to -3.8). Thus, when selecting among azithromycin, levofloxacin, and amoxicillin-based antibiotics, clinicians should weigh the relative antimicrobial benefits of these drugs against their potential cardiac risks.


Assuntos
Azitromicina , Insuficiência Renal , Amoxicilina , Combinação Amoxicilina e Clavulanato de Potássio , Antibacterianos/efeitos adversos , Azitromicina/efeitos adversos , Morte Súbita Cardíaca/epidemiologia , Morte Súbita Cardíaca/etiologia , Fluoroquinolonas , Humanos , Levofloxacino/efeitos adversos , Diálise Renal/efeitos adversos , Insuficiência Renal/induzido quimicamente , Estados Unidos/epidemiologia
20.
Mol Carcinog ; 61(7): 643-654, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35512605

RESUMO

Cancer stem cells (CSCs) virtually present in all tumors albeit in small numbers are primarily responsible for driving cancer progression, metastasis, drug resistance, and recurrence. Prostate cancer (PCa) is the second most frequent cancer in men worldwide, and castration resistant prostate cancer (CRPC) remains a major challenge despite the tremendous advancements in medicine. Currently, none of the available treatment options are effective in treating CRPC. We earlier reported that VNPP433-3ß, the lead next-generation galeterone analog is effective in treating preclinical in vivo models of CRPC. In this study using RNA-seq, cytological, and biochemical methods, we report that VNPP433-3ß inhibits prostate CSCs by targeting key pathways critical to stemness and epithelial-mesenchymal transition. VNPP433-3ß inhibits CSCs in PCa, presumably by degrading the androgen receptor (AR) thereby decreasing the AR-mediated transcription of several stem cell markers including BMI1 and KLF4. Transcriptome analyses by RNA-seq, Ingenuity Pathway Analysis, and Gene Set Enrichment Analysis demonstrate that VNPP433-3ß inhibits transcription of several genes and functional pathways critical to the prostate CSCs thereby inhibiting CSCs in PCa besides targeting the bulk of the tumor.


Assuntos
Neoplasias de Próstata Resistentes à Castração , Androstadienos , Benzimidazóis , Linhagem Celular Tumoral , Transição Epitelial-Mesenquimal , Perfilação da Expressão Gênica , Humanos , Masculino , Células-Tronco Neoplásicas/patologia , Próstata/patologia , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Receptores Androgênicos/genética , Receptores Androgênicos/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA