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1.
Methods Enzymol ; 694: 137-165, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38492949

RESUMO

This chapter explores advanced single-molecule techniques for studying protein-DNA interactions, particularly focusing on Replication Protein A (RPA) using a force-fluorescence setup. It combines magnetic tweezers (MT) with total internal reflection fluorescence (TIRF) microscopy, enabling detailed observation of DNA behavior under mechanical stress. The chapter details the use of DNA hairpins and bare DNA to examine RPA's binding dynamics and its influence on DNA's mechanical properties. This approach provides deeper insights into RPA's role in DNA replication, repair, and recombination, highlighting its significance in maintaining genomic stability.


Assuntos
DNA de Cadeia Simples , DNA , Fluorescência , Replicação do DNA , Proteínas de Ligação a DNA/metabolismo
2.
J Am Chem Soc ; 146(7): 4393-4401, 2024 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-38329893

RESUMO

For the construction of hierarchical superstructures with biaxial anisotropic absorption, a newly synthesized diacetylene-functionalized bipyridinium is self-assembled to use an electron-accepting host for capturing and arranging guests. The formation of the donor-acceptor complex triggers an intermolecular charge transfer, leading to chromophore activation. Polarization-dependent multichroic thin films are prepared through a sequential process of single-coating, self-assembly, and topochemical polymerization of host-guest chromophores. Molecular packing structures constructed in the single-layer optical thin film possess orthogonal absorption axes for two different wavelengths. By tuning the linear polarization angle, the color of the optical thin film can be intentionally controlled. This single-layered multichroic film provides a new pathway for the development of anticounterfeiting and multiplexing encryptions.

3.
Nutr Res Pract ; 18(1): 149-164, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38352210

RESUMO

BACKGROUND/OBJECTIVES: The economic recession caused by the coronavirus disease 2019 pandemic disproportionately affected poor and vulnerable populations globally. Better uunderstanding of vulnerability to shocks in food supply and demand in the Asia Pacific region is needed. SUBJECTS/METHODS: Using secondary data from rapid assessment surveys during the pandemic response (n = 10,420 in mid-2020; n = 6,004 in mid-2021) in India, Indonesia, Myanmar, and Vietnam, this study examined the risk factors for reported income reduction or job loss in mid-2021 and the temporal trend in food security status (household food availability, and market availability and affordability of essential items) from mid-2020 to mid-2021. RESULTS: The proportion of job loss/reduced household income was highest in India (60.4%) and lowest in Indonesia (39.0%). Urban residence (odds ratio [OR] range, 2.20-4.11; countries with significant results only), female respondents (OR range, 1.40-1.69), engagement in daily waged labor (OR range, 1.54-1.68), and running a small trade/business (OR range, 1.66-2.71) were significantly associated with income reduction or job loss in three out of 4 countries (all P < 0.05). Food stock availability increased significantly in 2021 compared to 2020 in all four countries (OR range, 1.91-4.45) (all P < 0.05). Availability of all essential items at markets increased in India (OR range, 1.45-3.99) but decreased for basic foods, hygiene items, and medicine in Vietnam (OR range, 0.81-0.86) in 2021 compared to 2020 (all P < 0.05). In 2021, the affordability of all essential items significantly improved in India (OR range, 1.18-3.49) while the affordability of rent, health care, and loans deteriorated in Indonesia (OR range, 0.23-0.71) when compared to 2020 (all P < 0.05). CONCLUSIONS: Long-term social protection programs need to be carefully designed and implemented to address food insecurity among vulnerable groups, considering each country's market conditions, consumer food purchasing behaviors, and financial support capacity.

4.
Am J Trop Med Hyg ; 110(2): 270-273, 2024 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-38190753

RESUMO

Cryptococcus neoformans infections occur most frequently in immunocompromised patients. Here, we report a case of cryptococcal meningitis in a previously immunocompetent 78-year-old female patient after treatment of COVID-19. Underlying diseases included hypertension, hyperlipidemia, and diabetes. The patient was critically ill and was treated with remdesivir, baricitinib, and dexamethasone. During hospitalization, her mental state changed, and C. neoformans was detected in the cerebrospinal fluid. She died despite receiving antifungal treatment. Treatment of COVID-19 may be a predisposing factor for C. neoformans infection. There is a need for concern and countermeasures for opportunistic fungal infections that may accompany COVID-19.


Assuntos
COVID-19 , Cryptococcus neoformans , Meningite Criptocócica , Humanos , Feminino , Idoso , Meningite Criptocócica/diagnóstico , Meningite Criptocócica/tratamento farmacológico , Antifúngicos/uso terapêutico
5.
BMC Infect Dis ; 24(1): 3, 2024 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-38166787

RESUMO

BACKGROUNDS: Remdesivir (RDV) is an antiviral agent approved for the treatment of coronavirus disease 2019 (COVID-19); however, is not recommended for patients with renal impairment. Due to limitations associated with prospective clinical trials, real-world data on the safety and efficacy of RDV in patients with renal impairment are necessary. METHODS: Propensity score-matched (PSM) retrospective analysis was conducted between March 2020 and September 2022 in COVID-19 patients with an eGFR < 30 mL/min in four Korean hospitals. The RDV treatment group was matched to the untreated control group. The safety and clinical outcomes in patients who received RDV were analyzed. RESULTS: A total of 564 patients were enrolled; 229 patients received RDV either for treatment or prophylaxis. On day 5, no difference in nephrotoxicity was observed between the two groups, and liver enzyme levels were within the normal range. In multivariate analysis for new dialysis, RDV treatment was not a risk factor for new dialysis. Among the 564 patients, 417 were indicated for a 5-day course of RDV treatment and 211 patients were treated with RDV. After PSM, no differences in the clinical outcomes were observed between the two groups. CONCLUSION: RDV use in COVID-19 patients with renal impairment did not result in significant nephrotoxicity or hepatotoxicity.


Assuntos
COVID-19 , Insuficiência Renal , Humanos , Tratamento Farmacológico da COVID-19 , Pontuação de Propensão , Estudos Prospectivos , Estudos Retrospectivos , Insuficiência Renal/complicações , Antivirais/efeitos adversos
6.
Eur Arch Otorhinolaryngol ; 281(2): 731-735, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37555931

RESUMO

PURPOSE: This study is to evaluate the duration of facial nerve enhancement in gadolinium-enhanced temporal bone MRI after the onset of acute facial palsy. METHODS: Gd-enhanced MRI imagines were examined in 13 patients with idiopathic acute facial palsy within 14 days after the onset. The degree of facial nerve function was measured according to the House-Brackmann (H-B) grading system at their first visit at outpatient clinic. The follow-up MRI was taken about 16.5 months (7-24 months) after onset of disease. The degree of facial nerve enhancement was measured with signal intensity (SI) which was quantitatively analyzed using the region-of-interest (ROI) measurements for each segment of the facial nerve. SI was statistically analyzed by comparing SI values of contralateral site and ipsilateral site using the paired t test with SPSS program. RESULTS: The gadolinium enhancement was statistically increased at labyrinthine segment and geniculate ganglion area of facial nerve at initial temporal bone MRI. The gadolinium enhancement was statistically decreased at all the segments of facial nerve except tympanic segment (p < 0.05) at follow-up MRI. CONCLUSIONS: The facial nerve enhancement in Gd-enhanced MRI images prolonged more than 21 months of the onset. The newly developed pathologic lesions of acute facial palsy especially occur at the site of labyrinthine and geniculate ganglion.


Assuntos
Paralisia de Bell , Paralisia Facial , Humanos , Paralisia Facial/diagnóstico por imagem , Paralisia Facial/etiologia , Paralisia Facial/patologia , Nervo Facial/diagnóstico por imagem , Nervo Facial/patologia , Meios de Contraste , Gadolínio , Paralisia de Bell/diagnóstico por imagem , Osso Temporal/diagnóstico por imagem , Osso Temporal/patologia , Imageamento por Ressonância Magnética/métodos
7.
Nucleic Acids Res ; 52(1): 259-273, 2024 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-37994723

RESUMO

R-loops are three-stranded nucleic acid structures that can cause replication stress by blocking replication fork progression. However, the detailed mechanism underlying the collision of DNA replication forks and R-loops remains elusive. To investigate how R-loops induce replication stress, we use single-molecule fluorescence imaging to directly visualize the collision of replicating Phi29 DNA polymerase (Phi29 DNAp), the simplest replication system, and R-loops. We demonstrate that a single R-loop can block replication, and the blockage is more pronounced when an RNA-DNA hybrid is on the non-template strand. We show that this asymmetry results from secondary structure formation on the non-template strand, which impedes the progression of Phi29 DNAp. We also show that G-quadruplex formation on the displaced single-stranded DNA in an R-loop enhances the replication stalling. Moreover, we observe the collision between Phi29 DNAp and RNA transcripts synthesized by T7 RNA polymerase (T7 RNAp). RNA transcripts cause more stalling because of the presence of T7 RNAp. Our work provides insights into how R-loops impede DNA replication at single-molecule resolution.


Assuntos
Replicação do DNA , Estruturas R-Loop , Imagem Individual de Molécula , RNA/química , DNA Polimerase Dirigida por DNA/metabolismo
8.
DNA Repair (Amst) ; 133: 103612, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38128155

RESUMO

The demand for direct observation of biomolecular interactions provides new insights into the molecular mechanisms underlying many biological processes. Single-molecule imaging techniques enable real-time visualization of individual biomolecules, providing direct observations of protein machines. Various single-molecule imaging techniques have been developed and have contributed to breakthroughs in biological research. One such technique is the DNA curtain, a novel, high-throughput, single-molecule platform that integrates lipid fluidity, nano-fabrication, microfluidics, and fluorescence imaging. Many DNA metabolic reactions, such as replication, transcription, and chromatin dynamics, have been studied using DNA curtains. In particular, the DNA curtain platform has been intensively applied in investigating the molecular details of DNA repair processes. This article reviews DNA curtain techniques and their applications for imaging DNA repair proteins.


Assuntos
Reparo do DNA , DNA , DNA/metabolismo , Cromatina , Nanotecnologia/métodos
9.
J Int Adv Otol ; 19(6): 468-471, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38088318

RESUMO

BACKGROUND: The prevalence of sudden sensorineural hearing loss and facial palsy in patients with vestibular schwannoma and the association of sudden sensorineural hearing loss or facial palsy with vestibular schwannoma were investigated based on the population data of Korea. METHODS: This retrospective study used the Korean National Health Insurance Service data. Patients with vestibular schwannoma and those with a previous history of sudden sensorineural hearing loss or facial palsy were identified based on diagnostic, medication, magnetic resonance imaging, or audiometric codes from 2005 to 2020. The control group was established with propensity score matching. The risk for vestibular schwannoma in patients with a previous history of sudden sensorineural hearing loss or facial palsy was analyzed. RESULTS: There were 5751 patients in the vestibular schwannoma group and 23004 in the control group. The rate of patients with a previous history of sudden sensorineural hearing loss in the vestibular schwannoma group (25.8%) was significantly higher than in the control group (P -lt; .0001), as was the rate of patients with a previous history of facial palsy in the vestibular schwannoma group (4.7%) (P -lt; .0001). Previous history of sudden sensorineural hearing loss was a significant risk factor for vestibular schwannoma (hazard ratio=7.109, 95% confidence interval=6.696-7.547). Previous history of facial palsy was also a significant risk factor for vestibular schwannoma (hazard ratio=3.048, 95% confidence interval=2.695-3.447). CONCLUSION: The prevalence of sudden sensorineural hearing loss or facial palsy was significantly higher in patients with vestibular schwannoma than in those without vestibular schwannoma. Based on the population data of Korea, sudden sensorineural hearing loss and facial palsy were significant risk factors for vestibular schwannoma.


Assuntos
Paralisia de Bell , Paralisia Facial , Perda Auditiva Neurossensorial , Perda Auditiva Súbita , Neuroma Acústico , Humanos , Neuroma Acústico/complicações , Neuroma Acústico/epidemiologia , Neuroma Acústico/diagnóstico , Paralisia Facial/epidemiologia , Estudos Retrospectivos , Perda Auditiva Neurossensorial/etiologia , Perda Auditiva Neurossensorial/complicações , Perda Auditiva Súbita/etiologia , Perda Auditiva Súbita/complicações , Paralisia de Bell/complicações , Paralisia de Bell/epidemiologia , República da Coreia/epidemiologia
10.
Sensors (Basel) ; 23(23)2023 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-38067702

RESUMO

This paper introduces an n-type pseudo-static gain cell (PS-nGC) embedded within dynamic random-access memory (eDRAM) for high-speed processing-in-memory (PIM) applications. The PS-nGC leverages a two-transistor (2T) gain cell and employs an n-type pseudo-static leakage compensation (n-type PSLC) circuit to significantly extend the eDRAM's retention time. The implementation of a homogeneous NMOS-based 2T gain cell not only reduces write access times but also benefits from a boosted write wordline technique. In a comparison with the previous pseudo-static gain cell design, the proposed PS-nGC exhibits improvements in write and read access times, achieving 3.27 times and 1.81 times reductions in write access time and read access time, respectively. Furthermore, the PS-nGC demonstrates versatility by accommodating a wide supply voltage range, spanning from 0.7 to 1.2 V, while maintaining an operating frequency of 667 MHz. Fabricated using a 28 nm complementary metal oxide semiconductor (CMOS) process, the prototype features an efficient active area, occupying a mere 0.284 µm2 per bitcell for the 4 kb eDRAM macro. Under various operational conditions, including different processes, voltages, and temperatures, the proposed PS-nGC of eDRAM consistently provides speedy and reliable read and write operations.

11.
Angew Chem Int Ed Engl ; 62(52): e202314480, 2023 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-37955417

RESUMO

Deploying Ni-enriched (Ni≥95 %) layered cathodes for high energy-density lithium-ion batteries (LIBs) requires resolving a series of technical challenges. Among them, the structural weaknesses of the cathode, vigorous reactivity of the labile Ni4+ ion species, gas evolution and associated cell swelling, and thermal instability issues are critical obstacles that must be solved. Herein, we propose an intuitive strategy that can effectively ameliorate the degradation of an extremely high-Ni-layered cathode, the construction of ultrafine-scale microstructure and subsequent intergranular shielding of grains. The formation of ultrafine grains in the Ni-enriched Li[Ni0.96 Co0.04 ]O2 (NC96) cathode, achieved by impeding particle coarsening during cathode calcination, noticeably improved the mechanical durability and electrochemical performance of the cathode. However, the buildup of the strain-resistant microstructure in Mo-doped NC96 concurrently increased the cathode-electrolyte contact area at the secondary particle surface, which adversely accelerated parasitic reactions with the electrolyte. The intergranular protection of the refined microstructure resolved the remaining chemical instability of the Mo-doped NC96 cathode by forming an F-induced coating layer, effectively alleviating structural degradation and gas generation, thereby extending the battery's lifespan. The proposed strategies synergistically improved the structural and chemical durability of the NC96 cathode, satisfying the energy density, life cycle performance, and safety requirements for next-generation LIBs.

12.
ACS Appl Mater Interfaces ; 15(48): 55456-55465, 2023 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-37983537

RESUMO

Semiconducting polymer dots (Pdots) are brightly fluorescent nanoparticles of growing interest for bioanalysis and imaging. A recurring challenge with these materials is obtaining robust physical and colloidal stability and low nonspecific binding. Here, we prepared and characterized Pdots with bovine serum albumin (BSA) as the stabilizing agent (BSA-Pdots) instead of a more conventionally used amphiphilic polymer, both without and with cross-linking of the protein using glutaraldehyde (BSA(GA)-Pdots) or disuccinimidyl glutarate. Characterization included fluorescence properties; colloidal stability as a function of pH, ionic strength, and solvent perturbation; shape retention and hardness; and nonspecific binding with common assay substrates, fixed cells, and live cells. These properties were contrasted with the same properties for amphiphilic polymer-stabilized Pdots and silica-coated Pdots. On balance, the BSA-stabilized Pdots were similar or more favorable in their properties, with BSA(GA)-Pdots being especially advantageous. Bioconjugation of the BSA-stabilized Pdots was possible using amine-reactive active-ester chemistry, including biotinylation and bioorthogonal functionalization for immunoconjugation via tetrazine-strained-alkene click chemistry. These approaches were used for selective fluorescent labeling of cells based on ligand-receptor and antibody-antigen binding, respectively. Overall, direct BSA stabilization is a very promising strategy for preparing Pdots with improved physical and colloidal stability, reduced nonspecific interactions, and utility for in vitro diagnostics and other bioanalyses and imaging.


Assuntos
Nanopartículas , Pontos Quânticos , Semicondutores , Polímeros/química , Albumina Sérica , Fluorescência , Corantes , Soroalbumina Bovina , Pontos Quânticos/química
13.
Insects ; 14(10)2023 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-37887828

RESUMO

The onion maggot, Delia antiqua (Meigen), is one of the most important insect pests to agricultural crops within Allium genus, such as onions and garlic, worldwide. This study was conducted to understand the seasonal abundance of this pest, with special reference to the hot summer effect (HSE), which was incorporated into the model of summer diapause termination (SDT). We assumed that hot summer temperatures arrested the development of pupae during summer diapause. The estimated SDT curve showed that it occurred below a high-temperature limit of 22.1 °C and peaked at 16 °C. Accordingly, HSE resulted in delaying the late season fly abundance after summer, namely impacting the third generation. In Jinju, South Korea, the activity of D. antiqua was observed to cease for more than two months in the hot summer and this pattern was well described by model outputs. In the warmer Jeju Island region, Korea, the late season emergence was predicted to be greatly delayed, and D. antiqua did not exhibit a specific peak in the late season in the field. The abundance patterns observed in Korea were very different from those in countries such as the United States, Canada, and Germany. These regions are located at a much higher latitude (42° N to 53° N) than Korea (33° N to 35° N), and their HSE was less intense, showing overlapped or slightly separated second and third generation peaks. Consequently, our modeling approach for the summer diapause termination effectively explained the abundance patterns of D. antiqua in the late season. Also, the model will be useful for determining spray timing for emerging adults in late summer as onion and garlic are sown in the autumn in Korea.

14.
Commun Biol ; 6(1): 960, 2023 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-37735522

RESUMO

Human ATP-binding cassette transporter subfamily B6 (ABCB6) is a mitochondrial ATP-driven pump that translocates porphyrins from the cytoplasm into mitochondria for heme biosynthesis. Within the transport pathway, a conserved aromatic residue W546 located in each monomer plays a pivotal role in stabilizing the occluded conformation via π-stacking interactions. Herein, we employed cryo-electron microscopy to investigate the structural consequences of a single W546A mutation in ABCB6, both in detergent micelles and nanodiscs. The results demonstrate that the W546A mutation alters the conformational dynamics of detergent-purified ABCB6, leading to entrapment of the transporter in an outward-facing transient state. However, in the nanodisc system, we observed a direct interaction between the transporter and a phospholipid molecule that compensates for the absence of the W546 residue, thereby facilitating the normal conformational transition of the transporter toward the occluded state following ATP hydrolysis. The findings also reveal that adoption of the outward-facing conformation causes charge repulsion between ABCB6 and the bound substrate, and rearrangement of key interacting residues at the substrate-binding site. Consequently, the affinity for the substrate is significantly reduced, facilitating its release from the transporter.


Assuntos
Detergentes , Porfirinas , Humanos , Microscopia Crioeletrônica , Transportadores de Cassetes de Ligação de ATP/genética , Proteínas de Membrana Transportadoras , Trifosfato de Adenosina
15.
Front Immunol ; 14: 1254415, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37705969

RESUMO

Immunity-related GTPase B10 (IRGB10) is a crucial member of the interferon (IFN)-inducible GTPases and plays a vital role in host defense mechanisms. Following infection, IRGB10 is induced by IFNs and functions by liberating pathogenic ligands to activate the inflammasome through direct disruption of the pathogen membrane. Despite extensive investigation into the significance of the cell-autonomous immune response, the precise molecular mechanism underlying IRGB10-mediated microbial membrane disruption remains elusive. Herein, we present two structures of different forms of IRGB10, the nucleotide-free and GppNHp-bound forms. Based on these structures, we identified that IRGB10 exists as a monomer in nucleotide-free and GTP binding states. Additionally, we identified that GTP hydrolysis is critical for dimer formation and further oligomerization of IRGB10. Building upon these observations, we propose a mechanistic model to elucidate the working mechanism of IRGB10 during pathogen membrane disruption.


Assuntos
Brônquios , GTP Fosfo-Hidrolases , Hidrólise , Inflamassomos , Nucleotídeos , Guanosina Trifosfato
16.
J Anal Toxicol ; 47(9): 858-866, 2023 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-37698167

RESUMO

Desalkylgidazepam, also known as bromonordiazepam, is the latest designer benzodiazepine to appear in postmortem blood samples in British Columbia. Our laboratory was first alerted to the presence of desalkylgidazepam in seized drug samples in May 2022, and the analyte was added to an in-house library shortly thereafter. Previously acquired spectra from routine death investigation cases were reprocessed using the updated library with the first presumptive identification of desalkylgidazepam occurring in a sample received in April 2022. A standard addition method for the quantitation of desalkylgidazepam in blood samples (from femoral, iliac, jugular and subclavian veins) was validated and consequently used to confirm presence and concentrations of the drug in 63 cases, with an average concentration of 42.2 ± 44.0 ng/mL (median concentration: 24.5 ng/mL; range: 3.7-220.6 ng/mL). Similar to detections of other novel benzodiazepines, co-occurrence of desalkylgidazepam with opioids and/or stimulants was common. To our knowledge, this paper is the first to report desalkylgidazepam concentrations in postmortem blood samples.


Assuntos
Benzodiazepinas , Estimulantes do Sistema Nervoso Central , Analgésicos Opioides , Autopsia , Toxicologia Forense
17.
J Am Heart Assoc ; 12(16): e029484, 2023 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-37548161

RESUMO

Background Real-world evidence for the selection of gatekeeping studies in patients with suspected coronary syndromes is limited. Methods and Results We identified 27 036 patients who underwent coronary computed tomography angiography (CCTA), single-photon emission computed tomography, and the treadmill test for suspected coronary syndromes from the Korean National Health Insurance Service-National Sample Cohort between 2006 and 2014. The primary end point was a composite of cardiac death and myocardial infarction, and the secondary end point was a composite of the primary end point and revascularization. During a median follow-up of 5.4 years, the risk of both primary and secondary end points was significantly higher in the single-photon emission computed tomography group (hazard ratio [HR], 1.81 [95% CI, 1.34-2.45]; and HR, 1.42 [95% CI, 1.22-1.66]), but significantly lower in the treadmill test group (HR, 0.53 [95% CI, 0.42-0.67]; and HR, 0.69 [95% CI, 0.62-0.76]) compared with the CCTA group. After balancing baseline risk factors, there was no significant difference in the primary end point in those with single-photon emission computed tomography (HR, 1.11 [95% CI, 0.78-1.57]; P=0.58) or treadmill test (HR, 0.84 [95% CI, 0.65-1.08]; P=0.18) groups, compared with the CCTA group. The event rate of the secondary end point was significantly lower in the treadmill test group than in the CCTA group (HR, 0.87 [95% CI, 0.78-0.96]; P=0.008). Conclusions Compared with functional testing, initial CCTA was not associated with a lower rate of cardiac death or myocardial infarction when used as an initial diagnostic test for patients with suspected coronary syndromes.


Assuntos
Doença da Artéria Coronariana , Infarto do Miocárdio , Humanos , Angiografia por Tomografia Computadorizada , Doença da Artéria Coronariana/diagnóstico , Angiografia Coronária/métodos , Síndrome , Infarto do Miocárdio/diagnóstico , Infarto do Miocárdio/epidemiologia
18.
Sci Rep ; 13(1): 12582, 2023 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-37537250

RESUMO

Glycopeptide antibiotics (vancomycin and teicoplanin) are usually used for the treatment of Staphylococcus epidermidis infections owing to their increased oxacillin resistance. However, S. epidermidis strains with decreased susceptibility to teicoplanin have become increasingly incident in recent years. We aimed to identify the characteristics of teicoplanin-non-susceptible (Teico-NS) S. epidermidis isolated at our hospital and analyze its relationship with teicoplanin usage. We retrospectively evaluated 328 S. epidermidis strains isolated from clinical isolates between January 2016 and December 2021. All strains were susceptible to vancomycin (minimal inhibitory concentration (MIC) ≤ 4 mg/L). The annual incidence for S. epidermidis strains with an elevated teicoplanin MIC of 8 mg/L ranged from 22.2 to 28.9%. In addition, in 2021, the number of S. epidermidis strains with teicoplanin MIC ≥ 16 mg/L rapidly increased (n = 13, 32.5%). Furthermore, teicoplanin use increased annually until 2019; however, in 2020, it decreased abruptly due to the COVID 19 pandemic. Thus, we could not confirm the existence of a clear correlation between teicoplanin usage and increased incidence of S. epidermidis with reduced teicoplanin-susceptibility. We showed the increased incidence of Teico-NS S. epidermidis in recent years. Further studies are needed to identify the mechanisms and risk factors for teicoplanin-resistance in S. epidermidis.


Assuntos
COVID-19 , Infecções Estafilocócicas , Humanos , Teicoplanina/farmacologia , Vancomicina/farmacologia , Estudos Retrospectivos , Staphylococcus epidermidis , Incidência , Staphylococcus , Antibacterianos/farmacologia , Testes de Sensibilidade Microbiana , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/epidemiologia
19.
Biomater Sci ; 11(18): 6177-6192, 2023 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-37504889

RESUMO

Radiation therapy (RT) is a mainstream clinical approach in cancer treatment. However, the therapeutic efficacy of RT is greatly hindered by the presence of excessive hydrogen peroxide (H2O2) in the hypoxic region of the solid tumor, thus leading to tumor recurrence and metastasis. Herein, a thioketal-linked amphiphilic nano-assembly (MTS) loaded with hydrophobic manganese oxide (HMO) nanoparticles (MTS@HMO) is examined as a promising multi-purpose reactive oxygen species (ROS)-catalytic nanozyme for transforming an RT-resistant hypoxic tumor microenvironment (TME) into an RT-susceptible one by scavenging ROS in the hypoxic core of the solid tumor. After intravenous injection, the MTS@HMO nano-assembly was able to sense and be degraded by the abundant ROS in the hypoxic TME, thereby releasing HMO particles for subsequent scavenging of H2O2. The oxygen generated during peroxide scavenging then relieved the hypoxic TME, thereby resulting in an increased sensitivity of the hypoxic tumor tissue towards RT. Moreover, the in situ hypoxic status was monitored via the T1-enhanced magnetic resonance (MR) imaging of the Mn2+ ions generated by the ROS-mediated degradation of HMO. The in vitro results demonstrated a significant H2O2 elimination and enhanced oxygen generation after the treatment of the MTS@HMO nano-assembly with tumor cells under hypoxic conditions, compared to the control MTS group. In addition, the combination of RT and pre-treatment with MTS@HMO nano-assembly significantly amplified the permanent DNA strand breaks in tumor cells compared to the control RT group. More importantly, the in vivo results proved that the systemic injection of the MTS@HMO nano-assembly prior to RT irradiation enhanced the RT-mediated tumor suppression and down-regulated the hypoxic marker of HIF-1α in the solid tumor compared to the control RT group. Overall, the present work demonstrates the great potential of the versatile ROS-catalytic hypoxia modulating strategy using the MTS@HMO nano-assembly to enhance the RT-induced antitumor efficacy in hypoxic solid tumors.


Assuntos
Neoplasias do Colo , Fotoquimioterapia , Humanos , Espécies Reativas de Oxigênio/metabolismo , Peróxido de Hidrogênio/química , Linhagem Celular Tumoral , Hipóxia/tratamento farmacológico , Hipóxia/metabolismo , Hipóxia/patologia , Oxigênio/metabolismo , Neoplasias do Colo/radioterapia , Neoplasias do Colo/tratamento farmacológico , Microambiente Tumoral , Fotoquimioterapia/métodos
20.
Stem Cells Transl Med ; 12(7): 485-495, 2023 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-37350544

RESUMO

Bone marrow-derived stem cells are self-renewing and multipotent adult stem cells that differentiate into several types of cells. Here, we investigated a unique combination of 4 differentiation-inducing factors (DIFs), including putrescine (Put), glucosamine (GlcN), nicotinamide, and BP-1-102, to develop a differentiation method for inducing mature insulin-producing cells (IPCs) and apply this method to bone marrow mononucleated cells (BMNCs) isolated from mice. BMNCs, primed with the 4 soluble DIFs, were differentiated into functional IPCs. BMNCs cultured under the defined conditions synergistically expressed multiple genes, including those for PDX1, NKX6.1, MAFA, NEUROG3, GLUT2, and insulin, related to pancreatic beta cell development and function. They produced insulin/C-peptide and PDX1, as assessed using immunofluorescence and flow cytometry. The induced cells secreted insulin in a glucose-responsive manner, similar to normal pancreatic beta cells. Grafting BMNC-derived IPCs under kidney capsules of mice with streptozotocin (STZ)-induced diabetes alleviated hyperglycemia by lowering blood glucose levels, enhancing glucose tolerance, and improving glucose-stimulated insulin secretion. Insulin- and PDX1-expressing cells were observed in the IPC-bearing graft sections of nephrectomized mice. Therefore, this study provides a simple protocol for BMNC differentiation, which can be a novel approach for cell-based therapy in diabetes mellitus.


Assuntos
Diabetes Mellitus Experimental , Células Secretoras de Insulina , Células-Tronco Mesenquimais , Camundongos , Animais , Medula Óssea , Diferenciação Celular , Glucose , Diabetes Mellitus Experimental/terapia , Insulina , Células da Medula Óssea
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