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1.
Clin Infect Dis ; 78(5): 1214-1221, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38381586

RESUMO

BACKGROUND: Nontoxigenic Corynebacterium diphtheriae, often associated with wounds, can rarely cause infective endocarditis (IE). Five patients with C. diphtheriae IE were identified within 12 months at a Seattle-based hospital system. We reviewed prior C. diphtheriae-positive cultures to determine if detections had increased over time and evaluated epidemiologic trends. METHODS: We conducted a formal electronic health record search to identify all patients aged ≥18 years with C. diphtheriae detected in a clinical specimen (ie, wound, blood, sputum) between 1 September 2020 and 1 April 2023. We collected patient demographics, housing status, comorbidities, substance-use history, and level of medical care required at detection. We extracted laboratory data on susceptibilities of C. diphtheriae isolates and on other pathogens detected at the time of C. diphtheriae identification. RESULTS: Between 1 September 2020 and 1 April 2023, 44 patients (median age, 44 years) had a C. diphtheriae-positive clinical culture, with most detections occurring after March 2022. Patients were predominantly male (75%), White (66%), unstably housed (77%), and had a lifetime history of injecting drugs (75%). Most C. diphtheriae-positive cultures were polymicrobial, including wound cultures from 36 (82%) patients and blood cultures from 6 (14%) patients, not mutually exclusive. Thirty-four patients (77%), including all 5 patients with C. diphtheriae IE, required hospital admission for C. diphtheriae or a related condition. Of the 5 patients with IE, 3 died of IE and 1 from COVID-19. CONCLUSIONS: Findings suggest a high-morbidity outbreak disproportionately affecting patients who use substances and are unstably housed.


Assuntos
Corynebacterium diphtheriae , Difteria , Humanos , Masculino , Adulto , Feminino , Washington/epidemiologia , Pessoa de Meia-Idade , Corynebacterium diphtheriae/isolamento & purificação , Difteria/epidemiologia , Difteria/microbiologia , Endocardite Bacteriana/epidemiologia , Endocardite Bacteriana/microbiologia , Adulto Jovem , Idoso , Antibacterianos/uso terapêutico , Endocardite/microbiologia , Endocardite/epidemiologia
2.
Artigo em Inglês | MEDLINE | ID: mdl-38072884

RESUMO

The development of hydrogen energy sources based on electrochemical water splitting is of increasing interest due to its advantages in energy and environmental fields. In this study, Co3O4 was decorated on carbon cloth (CC) by a hydrothermal method and was used as an electrode for water splitting. The structural and morphological properties of the materials are assessed using a range of reliable techniques such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) with EDX mapping, and diffuse reflectance spectroscopy (DRS). Results indicate that the Co3O4/CC material was synthesized at 140 °C for 9 h and calcined at 350 °C achieving a superior overall water-splitting activity in the direction of hydrogen evolution reaction (HER) reaction than that of the oxygen evolution reaction (OER). In detail, HER characteristics with an overpotential at -0.234 V and a current density at 10 mA cm-2. In addition, the Co3O4/CC material also gives overpotential at 0.54 V for OER process. Furthermore, the electrochemical surface area of Co3O4/CC material is 7.6 times higher than CC electrode. Moreover, the CC fabric is destroyed when the annealing temperature is higher than 350 °C, leading to a significant decrease in the activity of Co3O4/CC. The as-prepared Co3O4 shows good adhesion and stability based on CC substrate without binder substance or further treatment of CC.

3.
PLoS One ; 18(9): e0291865, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37768910

RESUMO

Due to the significant resemblance in visual appearance, pill misuse is prevalent and has become a critical issue, responsible for one-third of all deaths worldwide. Pill identification, thus, is a crucial concern that needs to be investigated thoroughly. Recently, several attempts have been made to exploit deep learning to tackle the pill identification problem. However, most published works consider only single-pill identification and fail to distinguish hard samples with identical appearances. Also, most existing pill image datasets only feature single pill images captured in carefully controlled environments under ideal lighting conditions and clean backgrounds. In this work, we are the first to tackle the multi-pill detection problem in real-world settings, aiming at localizing and identifying pills captured by users during pill intake. Moreover, we also introduce a multi-pill image dataset taken in unconstrained conditions. To handle hard samples, we propose a novel method for constructing heterogeneous a priori graphs incorporating three forms of inter-pill relationships, including co-occurrence likelihood, relative size, and visual semantic correlation. We then offer a framework for integrating a priori with pills' visual features to enhance detection accuracy. Our experimental results have proved the robustness, reliability, and explainability of the proposed framework. Experimentally, it outperforms all detection benchmarks in terms of all evaluation metrics. Specifically, our proposed framework improves COCO mAP metrics by 9.4% over Faster R-CNN and 12.0% compared to vanilla YOLOv5. Our study opens up new opportunities for protecting patients from medication errors using an AI-based pill identification solution.


Assuntos
Benchmarking , Ambiente Controlado , Humanos , Reprodutibilidade dos Testes , Iluminação , Redes Neurais de Computação
4.
Am J Surg ; 225(1): 93-98, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36400601

RESUMO

BACKGROUND: Preoperative imaging in clinical stage II melanoma is not indicated per National Comprehensive Cancer Network (NCCN) guidelines but remains common in clinical practice. METHODS: Patients presenting with cutaneous clinical stage II melanoma from 2007 to 2019 were retrospectively reviewed. A clinical decision analysis with cost data was designed to understand ideal practice patterns in managing stage II melanoma, with pre-versus selective post-operative imaging as the initial decision node. RESULTS: There were 277 subjects included, and 143 underwent preoperative imaging (49.5%). This changed management (i.e. no surgery) in one patient (0.4%). Overall, 16 patients had additional findings on imaging (5.8%). Upfront surgery with selective postoperative imaging was a more cost-effective strategy than routine performance of preoperative imaging, with savings of $1677 per patient. CONCLUSION: Preoperative imaging is a low yield, costly approach for patients with clinical stage II melanoma with minimal impact on the decision to proceed with surgical management.


Assuntos
Melanoma , Neoplasias Cutâneas , Humanos , Melanoma/diagnóstico por imagem , Melanoma/cirurgia , Melanoma/patologia , Neoplasias Cutâneas/diagnóstico por imagem , Neoplasias Cutâneas/cirurgia , Neoplasias Cutâneas/patologia , Análise Custo-Benefício , Estudos Retrospectivos , Estadiamento de Neoplasias , Técnicas de Apoio para a Decisão , Melanoma Maligno Cutâneo
6.
Hemoglobin ; 46(4): 233-239, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35993587

RESUMO

Vietnam has a high thalassemia burden. We collected blood samples from 5880 pregnant Vietnamese women during prenatal health checks to assess thalassemia carrier frequency using combined gap-polymerase chain reaction (gap-PCR) and targeted next-generation sequencing (NGS). Thalassemia carriers were identified with prevalence of 13.13% (772), including 7.82% (460) carriers of α-thalassemia (α-thal), 5.31% (312) carriers of ß-thalassemia (ß-thal), and 0.63% (37) concurrent α-/ß-thal carriers. Deletional mutations (368) accounted for 80.0% of α-thal carriers, of which, --SEA (Southeast Asian) (n = 254; 55.0%) was most prevalent, followed by the -α3.7 (rightward) (n = 66; 14.0%) and -α4.2 (leftward) (n = 45; 9.8%) deletions. Hb Westmead (HBA2: c.369C>G) (n = 53) and Hb Constant Spring (Hb CS or HBA2: c.427T>C) (in 28) are the two most common nondeletional α-globin variants, accounting for 11.5 and 6.0% of α-thal carriers. We detected 11 different ß-thal genotypes. Hb E (HBB: c.79G>A) (in 211) accounted for 67.6% of ß-thal carriers. The most common ß-thal genotypes were associated with mutations at codon 17 (A>T) (HBB: c.52A>T), codons 41/42 (-TTCT) (HBB: c.126_129delCTTT), and codon 71/72 (+A) (HBB: c.217_218insA) (prevalence 0.70%, 0.68%, and 0.2%, respectively). Based on mutation frequencies calculated in this study, estimates of 5021 babies in Vietnam are affected with clinically severe thalassemia annually. Our data suggest a higher thalassemia carrier frequency in Vietnam than previously reported. We established that combining NGS with gap-PCR creates an effective large-scale thalassemia screening method that can detect a broad range of mutations.


Assuntos
Talassemia alfa , Talassemia beta , Feminino , Humanos , Gravidez , Talassemia beta/diagnóstico , Talassemia beta/epidemiologia , Talassemia beta/genética , Globinas beta/genética , Gestantes , Vietnã/epidemiologia , Frequência do Gene , Talassemia alfa/diagnóstico , Talassemia alfa/epidemiologia , Talassemia alfa/genética , Reação em Cadeia da Polimerase , Mutação , Códon , Genótipo , Sequenciamento de Nucleotídeos em Larga Escala
7.
Environ Monit Assess ; 194(10): 700, 2022 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-35987970

RESUMO

The large river basins throughout the world have undergone land-use/land-cover (LULC)-induced changes in river discharge and sediment load. Evaluating these changes is consequently important for efficient management of soil and water resources. In addition, these changes in the transboundary Mekong River Basin (Mekong RB) are not well-known. The present study aimed to investigate the impacts of LULC changes on river discharge and sediment load in the Mekong RB during the period 1980-2015 using Soil and Water Assessment Tool (SWAT). The SWAT model was calibrated and validated using measured data of daily river discharge and monthly sediment load. Analysis of LULC change showed a 2.35% decrease in forest land and a 2.29% increase in agricultural land during the period of 1997-2010. LULC changes in 1997 and 2010 caused increases in river discharge and sediment load by 0.24 to 0.32% and 1.78 to 2.86%, respectively in the study region. Moreover, the river discharge and sediment load of the Mekong River have significantly positive correlation with agricultural land and negative correlation with forest land. The findings give beneficial insights to implement appropriate strategies of water and soil conservation measures to adapt and mitigate the adverse impacts of LULC in the Mekong RB. Further study will consider the impact of future LULC changes and uncertainties associated with the LULC projections for future management of soil and water conservation in the study region.


Assuntos
Monitoramento Ambiental , Rios , Solo , Água , Movimentos da Água
8.
J Clin Microbiol ; 60(8): e0012222, 2022 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-35852363

RESUMO

Bloodstream infection poses a significant medical emergency that necessitates timely administration of appropriate antibiotics. Standard laboratory workup for antimicrobial susceptibility testing (AST) involves subculture of organisms from positive blood bottles followed by testing using broth microdilution; however, this process can take several days. The Accelerate Pheno Blood Culture panel (Pheno) provides rapid phenotypic testing of selected Gram-negative organisms directly from positive blood cultures. This has the potential to shorten the AST process to several hours and impact time to antimicrobial optimization and subsequent clinical outcomes; however, these metrics have not been assessed in pediatric populations. We retrospectively compared two patient cohorts with blood cultures positive for on-panel Gram-negative organisms: 82 cases tested by conventional AST methods, and 80 cases postintervention at our pediatric hospital. Susceptibility testing from the Pheno yielded 91.5% categorical agreement with a broth microdilution-based reference method with 7.4% minor error, 1.1% major error, and 0.1% very major error rates. The median time from blood culture positivity to AST decreased from 20.0 h to 9.7 h (P < 0.001), leading to an overall decrease in time from blood culture positivity to change in therapy from 36.0 h to 25.0 h (P < 0.001). There was no observed change in length of stay or 30-day mortality. Median duration on meropenem decreased from 64.8 h to 31.6 h (P = 0.04). We conclude the Pheno had accurate performance and that implementation allowed for faster AST reporting, improved time to optimal therapy, and decreased duration on meropenem in children.


Assuntos
Anti-Infecciosos , Bacteriemia , Infecções por Bactérias Gram-Negativas , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Anti-Infecciosos/uso terapêutico , Bacteriemia/diagnóstico , Bacteriemia/tratamento farmacológico , Criança , Bactérias Gram-Negativas , Infecções por Bactérias Gram-Negativas/tratamento farmacológico , Hospitais Pediátricos , Humanos , Meropeném , Testes de Sensibilidade Microbiana , Estudos Retrospectivos
9.
Clin Lab Med ; 42(2): 203-222, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35636822

RESUMO

Though rapid antigen tests have historically problematic performance characteristics for the diagnosis of respiratory viral infections such as influenza, they have attained an unprecedented level of use in the context of the COVID-19 pandemic. Ease of use and scalability of rapid antigen tests has facilitated a democratization and scale of testing beyond anything reasonably achievable by traditional laboratory-based testing. In this chapter, we discuss the performance characteristics of rapid antigen testing for SARS-CoV-2 detection and their application to non-traditional uses beyond clinical diagnostic testing.


Assuntos
COVID-19 , SARS-CoV-2 , COVID-19/diagnóstico , Humanos , Testes Imunológicos , Pandemias
10.
Langmuir ; 38(13): 4138-4146, 2022 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-35324210

RESUMO

Nitric oxide (NO) removal by photocatalytic oxidation over g-C3N4 has achieved more efficient results. However, there is a concern about the high NO-to-NO2 conversion yield of products, which is not suitable for the photocatalytic NO reaction. In this study, we modify g-C3N4 by WO3 nanoplates for the first time for photocatalytic NO oxidation over a WO3/g-C3N4 composite to enhance the green product selectivity under atmospheric conditions. The results indicate that the photocatalytic efficiency for NO removal by the WO3/g-C3N4 composite is drastically improved and achieves 52.5%, which is approximately 2.1 times higher than that of pure g-C3N4. Significantly, the green product (NO3-) selectivity of the WO3/g-C3N4 composite is 8.7 times higher than that of pure g-C3N4, and the selectivity remained high even after five cycles of photocatalytic tests. We also conclude that the enhanced green product selectivity of photocatalytic NO oxidation by the WO3/g-C3N4 composite is due to the separation and acceleration of the photogenerated charges of the WO3/g-C3N4 S-scheme heterojunction.

12.
Beilstein J Nanotechnol ; 13: 96-113, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35116216

RESUMO

Semiconducting SnO2 photocatalyst nanomaterials are extensively used in energy and environmental research because of their outstanding physical and chemical properties. In recent years, nitrogen oxide (NO x ) pollutants have received particular attention from the scientific community. The photocatalytic NO x oxidation will be an important contribution to mitigate climate change in the future. Existing review papers mainly focus on applying SnO2 materials for photocatalytic oxidation of pollutants in the water, while studies on the decomposition of gas pollutants are still being developed. In addition, previous studies have shown that the photocatalytic activity regarding NO x decomposition of SnO2 and other materials depends on many factors, such as physical structure and band energies, surface and defect states, and morphology. Recent studies have been focused on the modification of properties of SnO2 to increase the photocatalytic efficiency of SnO2, including bandgap engineering, defect regulation, surface engineering, heterojunction construction, and using co-catalysts, which will be thoroughly highlighted in this review.

13.
EBioMedicine ; 67: 103355, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33915337

RESUMO

BACKGROUND: There is increasing concern that persistent infection of SARS-CoV-2 within immunocompromised hosts could serve as a reservoir for mutation accumulation and subsequent emergence of novel strains with the potential to evade immune responses. METHODS: We describe three patients with acute lymphoblastic leukemia who were persistently positive for SARS-CoV-2 by real-time polymerase chain reaction. Viral viability from longitudinally-collected specimens was assessed. Whole-genome sequencing and serological studies were performed to measure viral evolution and evidence of immune escape. FINDINGS: We found compelling evidence of ongoing replication and infectivity for up to 162 days from initial positive by subgenomic RNA, single-stranded RNA, and viral culture analysis. Our results reveal a broad spectrum of infectivity, host immune responses, and accumulation of mutations, some with the potential for immune escape. INTERPRETATION: Our results highlight the potential need to reassess infection control precautions in the management and care of immunocompromised patients. Routine surveillance of mutations and evaluation of their potential impact on viral transmission and immune escape should be considered.


Assuntos
COVID-19/imunologia , Evasão da Resposta Imune , Mutação , Leucemia-Linfoma Linfoblástico de Células Precursoras/virologia , SARS-CoV-2/genética , COVID-19/virologia , Pré-Escolar , Evolução Molecular , Feminino , Genoma Viral , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Imunidade Humoral , Masculino , Leucemia-Linfoma Linfoblástico de Células Precursoras/imunologia , SARS-CoV-2/classificação , SARS-CoV-2/imunologia , Análise de Sequência de RNA , Sequenciamento Completo do Genoma , Adulto Jovem
14.
medRxiv ; 2021 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-33688673

RESUMO

Background: There is increasing concern that persistent infection of SARS-CoV-2 within immunocompromised hosts could serve as a reservoir for mutation accumulation and subsequent emergence of novel strains with the potential to evade immune responses. Methods: We describe three patients with acute lymphoblastic leukemia who were persistently positive for SARS-CoV-2 by real-time polymerase chain reaction. Viral viability from longitudinally-collected specimens was assessed. Whole-genome sequencing and serological studies were performed to measure viral evolution and evidence of immune escape. Findings: We found compelling evidence of ongoing replication and infectivity for up to 162 days from initial positive by subgenomic RNA, single-stranded RNA, and viral culture analysis. Our results reveal a broad spectrum of infectivity, host immune responses, and accumulation of mutations, some with the potential for immune escape. Interpretation: Our results highlight the need to reassess infection control precautions in the management and care of immunocompromised patients. Routine surveillance of mutations and evaluation of their potential impact on viral transmission and immune escape should be considered. Funding: The work was partially funded by The Saban Research Institute at Children's Hospital Los Angeles intramural support for COVID-19 Directed Research (X.G. and J.D.B.), the Johns Hopkins Center of Excellence in Influenza Research and Surveillance HHSN272201400007C (A.P.), NIH/NIAID R01AI127877 (S.D.B.), NIH/NIAID R01AI130398 (S.D.B.), NIH 1U54CA260517 (S.D.B.), an endowment to S.D.B. from the Crown Family Foundation, an Early Postdoc.Mobility Fellowship Stipend to O.F.W. from the Swiss National Science Foundation (SNSF), and a Coulter COVID-19 Rapid Response Award to S.D.B. L.G. is a SHARE Research Fellow in Pediatric Hematology-Oncology.

15.
Chemosphere ; 268: 129291, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33359837

RESUMO

In this report, the peroxymonosulfate activation over Ag/ZnO heterojunction under visible light (Ag/ZnO/PMS/Vis) for p-nitrophenol (p-NP) contaminant degradation was conducted in detail. Herein, the catalyst dosage was decreased, and the results showed that a dosage of 0.5 g L-1 Ag/ZnO and 4 mM PMS almost completely degraded 30 mg L-1 p-NP after 90 min of irradiation. In addition, the PMS activation mechanism of Ag/ZnO/PMS/Vis system was proposed by investigations of the influence of PMS concentration, the FTIR spectra, UV-Vis spectroscopy, and electrochemical analyses. Additionally, the role of SO4•- in the photocatalytic reaction is determined by a combination of a trapping test using isopropanol and tert-butanol as probe compounds and electron spin resonance (ESR) spectroscopy. This report provides a potential alternative to remove persistent organic contaminants in sewage using PMS incorporated with Ag/ZnO under visible light irradiation.


Assuntos
Óxido de Zinco , Luz , Nitrofenóis , Peróxidos , Prata
16.
J Clin Microbiol ; 59(2)2021 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-33239380

RESUMO

Testing efforts for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been burdened by the scarcity of testing materials and personal protective equipment for health care workers. The simple and painless process of saliva collection allows for widespread testing, but enthusiasm is hampered by variable performance compared to that of nasopharyngeal swab (NPS) samples. We prospectively collected paired NPS and saliva samples from a total of 300 unique adult and pediatric patients. SARS-CoV-2 RNA was detected in 32.2% (97/300) of the individuals using the TaqPath COVID-19 Combo kit (Thermo Fisher). Performance of saliva and NPS was compared against the total number of positives regardless of specimen type. The overall concordances for saliva and NPS were 91.0% (273/300) and 94.7% (284/300), respectively. The values for positive percent agreement (PPA) for saliva and NPS were 81.4% (79/97) and 89.7% (87/97), respectively. Saliva yielded detection of 10 positive cases that were negative by NPS. For symptomatic and asymptomatic pediatric patients not previously diagnosed with COVID-19, the performances of saliva and NPS were comparable (PPA, 82.4% versus 85.3%). The overall values for PPA for adults were 83.3% and 90.7% for saliva and NPS, respectively, with saliva yielding detection of 4 fewer cases than NPS. However, saliva performance for symptomatic adults was identical to NPS performance (PPA of 93.8%). With lower cost and self-collection capabilities, saliva can be an appropriate sample choice alternative to NPS for detection of SARS-CoV-2 in children and adults.


Assuntos
COVID-19/diagnóstico , SARS-CoV-2/isolamento & purificação , Saliva/virologia , Manejo de Espécimes/métodos , Adolescente , Adulto , COVID-19/patologia , COVID-19/virologia , Teste de Ácido Nucleico para COVID-19 , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Nasofaringe/virologia , Estudos Prospectivos , SARS-CoV-2/genética , Sensibilidade e Especificidade , Carga Viral , Adulto Jovem
17.
medRxiv ; 2020 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-33140064

RESUMO

Testing efforts for SARS-CoV-2 have been burdened by the scarcity of testing materials and personal protective equipment for healthcare workers. The simple and painless process of saliva collection allows for widespread testing, but enthusiasm is hampered by variable performance compared to nasopharyngeal swab (NPS) samples. We prospectively collected paired NPS and saliva samples from a total of 300 unique adult and pediatric patients. SARS-CoV-2 RNA was detected in 32.2% (97/300) of the individuals using the TaqPath COVID-19 Combo Kit (Thermo Fisher). Performance of saliva and NPS were compared against the total number of positives regardless of specimen type. The overall concordance for saliva and NPS was 91.0% (273/300) and 94.7% (284/300), respectively. The positive percent agreement (PPA) for saliva and NPS was 81.4% (79/97) and 89.7% (87/97), respectively. Saliva detected 10 positive cases that were negative by NPS. In symptomatic and asymptomatic pediatric patients not previously diagnosed with COVID-19, the performances of saliva and NPS were comparable (PPA: 82.4% vs 85.3%). The overall PPA for adults were 83.3% and 90.7% for saliva and NPS, respectively, with saliva detecting 4 cases less than NPS. However, saliva performance in symptomatic adults was identical to NPS (PPA of 93.8%). With lower cost and self-collection capabilities, saliva can be an appropriate alternative sample choice to NPS for detection of SARS-CoV-2 in children and adults. SUMMARY: Saliva is an acceptable alternative specimen compared to nasopharyngeal swabs for detection of SARS-CoV-2. Specifically, saliva demonstrated comparable performance to nasopharyngeal swabs in symptomatic and asymptomatic pediatric patients and in symptomatic adults.

18.
Mol Microbiol ; 114(6): 966-978, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32866331

RESUMO

A peptidoglycan (PG) cell wall composed of glycans crosslinked by short peptides surrounds most bacteria and protects them against osmotic rupture. In Escherichia coli, cell elongation requires crosslink cleavage by PG endopeptidases to make space for the incorporation of new PG material throughout the cell cylinder. Cell division, on the contrary, requires the localized synthesis and remodeling of new PG at midcell by the divisome. Little is known about the factors that modulate transitions between these two modes of PG biogenesis. In a transposon-insertion sequencing screen to identify mutants synthetically lethal with a defect in the division protein FtsP, we discovered that mutants impaired for cell division are sensitive to elevated activity of the endopeptidases. Increased endopeptidase activity in these cells was shown to interfere with the assembly of mature divisomes, and conversely, inactivation of MepS was found to suppress the lethality of mutations in essential division genes. Overall, our results are consistent with a model in which the cell elongation and division systems are in competition with one another and that control of PG endopeptidase activity represents an important point of regulation influencing the transition from elongation to the division mode of PG biogenesis.


Assuntos
Divisão Celular , Endopeptidases/metabolismo , Proteínas de Escherichia coli/metabolismo , Escherichia coli/fisiologia , Peptidoglicano/metabolismo , Parede Celular/genética , Cisteína Endopeptidases , Regulação Bacteriana da Expressão Gênica , Mutação
19.
ACS Omega ; 4(7): 12853-12859, 2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31460411

RESUMO

Removal of nitrogen oxide pollution has attracted much attention, and photocatalysis is considered as an effective method to treat polluted gas. Currently, modified semiconductors with approximate band gap are used as visible-light-driven photocatalysts. Herein, this is the first investigation of photocatalytic removal of NO under visible light over Cr-doped ZnO nanoparticles (Cr-ZnO NPs). Furthermore, the trapping species experiment and electron spin resonance measurement were conducted to identify the primary reactive factor of the photocatalytic reaction. In this study, Cr-ZnO NPs were synthesized by the sol-gel method with a narrow band gap, enhanced NO photocatalytic degradation performance, low NO2 conversion yield, and high stability under visible light.

20.
J Immunol ; 198(10): 3823-3834, 2017 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-28396318

RESUMO

Allergic disorders have now become a major worldwide public health issue, but the effective treatment options remain limited. We report a novel approach to block allergic reactivity by targeting the surface-bound IgE of the allergic effector cells via low-affinity anti-human IgE Abs with dissociation constants in the 10-6 to 10-8 M range. We demonstrated that these low-affinity anti-IgE mAbs bind to the cell surface-bound IgE without triggering anaphylactic degranulation even at high concentration, albeit they would weakly upregulate CD203c expression on basophils. This is in contrast to the high-affinity anti-IgE mAbs that trigger anaphylactic degranulation at low concentration. Instead, the low-affinity anti-IgE mAbs profoundly block human peanut- and cat-allergic IgE-mediated basophil CD63 induction indicative of anaphylactic degranulation; suppress peanut-, cat-, and dansyl-specific IgE-mediated passive cutaneous anaphylaxis; and attenuate dansyl IgE-mediated systemic anaphylaxis in human FcεRIα transgenic mouse model. Mechanistic studies reveal that the ability of allergic reaction blockade by the low-affinity anti-IgE mAbs was correlated with their capacity to downregulate the surface IgE and FcεRI level on human basophils and the human FcεRIα transgenic mouse bone marrow-derived mast cells via driving internalization of the IgE/FcεRI complex. Our studies demonstrate that targeting surface-bound IgE with low-affinity anti-IgE Abs is capable of suppressing allergic reactivity while displaying an excellent safety profile, indicating that use of low-affinity anti-IgE mAbs holds promise as a novel therapeutic approach for IgE-mediated allergic diseases.


Assuntos
Anafilaxia/prevenção & controle , Anticorpos Anti-Idiotípicos/imunologia , Afinidade de Anticorpos , Hipersensibilidade/prevenção & controle , Imunoglobulina E/imunologia , Anafilaxia/tratamento farmacológico , Anafilaxia/imunologia , Animais , Anticorpos Anti-Idiotípicos/administração & dosagem , Anticorpos Anti-Idiotípicos/metabolismo , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/metabolismo , Basófilos/imunologia , Degranulação Celular/imunologia , Citocinas/sangue , Citocinas/imunologia , Humanos , Hipersensibilidade/imunologia , Imunoglobulina E/metabolismo , Camundongos , Camundongos Transgênicos , Anafilaxia Cutânea Passiva/imunologia , Diester Fosfórico Hidrolases/imunologia , Ligação Proteica , Pirofosfatases/imunologia , Tetraspanina 30/imunologia
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