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Circulating plasma cells (CPCs) are detected in most multiple myeloma (MM) patients, both at diagnosis and on relapse. A small subset, plasma cell leukemia (PCL), represents a different biology and has a poor prognosis. In this retrospective analysis, we evaluated patients with primary (pPCL, n = 35) or secondary (sPCL, n = 49), with ≥5% CPCs and a smaller subset with lower CPCs of 1-4% (n = 20). The median age was 61 years; 45% were men and 54% were Black. High-risk cytogenetics were found in 87% and extramedullary disease in 47%. For the entire cohort, 75% received a proteasome inhibitor, 70% chemotherapy, 54% an immunomodulatory drug, 24% a daratumumab-based regimen and 26% an autologous stem cell transplant (ASCT). The treatments marginally improved the overall survival (OS) for pPCL vs. sPCL (13 vs. 3.5 months p = 0.002). However, the 5-year survival for the whole cohort was dismal at 11%. High-risk cytogenetics, low platelets, extramedullary disease and high LDH were independently associated with poor outcomes. Further research is urgently needed to expand the treatment options and improve the outcomes in PCL.
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BACKGROUND: Targeted muscle reinnervation (TMR) has been shown to reduce phantom limb pain (PLP) and residual limb pain (RLP) after major limb amputation. However, the effect of the timing of surgery on pain control and quality of life outcomes is controversial. We conducted a retrospective study to compare the outcomes of acute TMR for pain prevention with non-acute TMR for the treatment of established pain. METHODS: All patients treated with TMR in our institution between January 2018 and December 2021 were evaluated at 6, 12, 18 and 24 months post-operatively. Pain intensity and quality of life outcomes were assessed using the Brief Pain Inventory (Pain Severity and Pain Interference scales) and Pain Catastrophizing Scale. Outcomes were compared between acute and non-acute TMR using the Wilcoxon ranked-sum test or Fisher's exact test as appropriate. Multilevel mixed-effects linear regression was used to account for repeat measures and potential pain confounders. RESULTS: Thirty-two patients with 38 major limb amputations were included. Acute TMR patients reported significantly lower RLP and PLP scores, pain interference and pain catastrophisation at all time points (p < 0.05). Acute TMR was significantly associated with lower pain severity and pain interference in a linear mixed-effects model accounting for patient age, gender, amputation indication, amputation site, time post-TMR and repeated surveys (p < 0.05). There was no significant difference in the complication rate (p = 0.51). CONCLUSION: Acute TMR was associated with clinically and statistically significant pain outcomes that were better than that in non-acute TMR. This suggests that TMR should be performed with preventative intent, when possible, as part of a multidisciplinary approach to pain management, rather than deferred until the development of chronic pain.
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Amputação Cirúrgica , Músculo Esquelético , Medição da Dor , Membro Fantasma , Humanos , Masculino , Feminino , Amputação Cirúrgica/efeitos adversos , Pessoa de Meia-Idade , Estudos Retrospectivos , Membro Fantasma/prevenção & controle , Membro Fantasma/etiologia , Músculo Esquelético/inervação , Qualidade de Vida , Dor Pós-Operatória/etiologia , Dor Pós-Operatória/prevenção & controle , Dor Pós-Operatória/diagnóstico , Idoso , Transferência de Nervo/métodos , Adulto , Manejo da Dor/métodosRESUMO
White matter hyperintensities (WMHs) are commonly detected on T2-weighted magnetic resonance imaging (MRI) scans, occurring in both typical aging and Alzheimer's disease. Despite their frequent appearance and their association with cognitive decline, the molecular factors contributing to WMHs remain unclear. In this study, we investigated the transcriptomic profiles of two commonly affected brain regions with coincident AD pathology-frontal subcortical white matter (frontal-WM) and occipital subcortical white matter (occipital-WM)-and compared with age-matched healthy controls. Through RNA-sequencing in frontal- and occipital-WM bulk tissues, we identified an upregulation of genes associated with brain vasculature function in AD white matter. To further elucidate vasculature-specific transcriptomic features, we performed RNA-seq analysis on blood vessels isolated from these white matter regions, which revealed an upregulation of genes related to protein folding pathways. Finally, comparing gene expression profiles between AD individuals with high- versus low-WMH burden showed an increased expression of pathways associated with immune function. Taken together, our study characterizes the diverse molecular profiles of white matter changes in AD compared to normal aging and provides new mechanistic insights processes underlying AD-related WMHs.
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Complexo CD3 , Córnea , Modelos Animais de Doenças , Doença Enxerto-Hospedeiro , Linfócitos T , Animais , Camundongos , Córnea/patologia , Córnea/metabolismo , Doença Enxerto-Hospedeiro/diagnóstico , Doença Enxerto-Hospedeiro/imunologia , Doença Enxerto-Hospedeiro/metabolismo , Doença Enxerto-Hospedeiro/patologia , Complexo CD3/metabolismo , Linfócitos T/imunologia , Índice de Gravidade de Doença , Camundongos Endogâmicos C57BLRESUMO
The emergence of various variants of concern (VOCs) necessitates the development of more efficient vaccines for COVID-19. In this study, we established a rapid and robust production platform for a novel subunit vaccine candidate based on eukaryotic HEK-293 T cells. The immunogenicity of the vaccine candidate was evaluated in pigs. The results demonstrated that the pseudovirus neutralizing antibody (pNAb) titers reached 7751 and 306 for the SARS-CoV-2 Delta and Omicron variants, respectively, after the first boost. Subsequently, pNAb titers further increased to 10,201 and 1350, respectively, after the second boost. Additionally, ELISPOT analysis revealed a robust T-cell response characterized by IFN-γ (171 SFCs/106 cells) and IL-2 (101 SFCs/106 cells) production. Our study demonstrates that a vaccine candidate based on the Delta variant spike protein may provide strong and broad protection against the prototype SARS-CoV-2 and VOCs. Moreover, the strategy for the efficient and stable expression of recombinant proteins utilizing HEK-293 T cells can be employed as a universal platform for future vaccine development.
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Anticorpos Neutralizantes , Vacinas contra COVID-19 , COVID-19 , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus , Vacinas de Subunidades Antigênicas , Animais , Humanos , Células HEK293 , Vacinas contra COVID-19/imunologia , Vacinas de Subunidades Antigênicas/imunologia , SARS-CoV-2/imunologia , Anticorpos Neutralizantes/imunologia , Suínos , COVID-19/prevenção & controle , COVID-19/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Anticorpos Antivirais/imunologia , Linfócitos T/imunologia , Imunogenicidade da VacinaRESUMO
Tau aggregation is a hallmark of several neurodegenerative diseases, including Alzheimer's disease and frontotemporal dementia. There are disease-causing variants of the tau-encoding gene, MAPT, and the presence of tau aggregates is highly correlated with disease progression. However, the molecular mechanisms linking pathological tau to neuronal dysfunction are not well understood due to our incomplete understanding of the normal functions of tau in development and aging and how these processes change in the context of causal disease variants of tau. To address these questions in an unbiased manner, we conducted multi-omic characterization of iPSC-derived neurons harboring the MAPT V337M mutation. RNA-seq and phosphoproteomics revealed that both V337M tau and tau knockdown consistently perturbed levels of transcripts and phosphorylation of proteins related to axonogenesis or axon morphology. Surprisingly, we found that neurons with V337M tau had much lower tau phosphorylation than neurons with WT tau. We conducted functional genomics screens to uncover regulators of tau phosphorylation in neurons and found that factors involved in axonogenesis modified tau phosphorylation in both MAPT WT and MAPT V337M neurons. Intriguingly, the p38 MAPK pathway specifically modified tau phosphorylation in MAPT V337M neurons. We propose that V337M tau might perturb axon morphology pathways and tau hypophosphorylation via a "loss of function" mechanism, which could contribute to previously reported cognitive changes in preclinical MAPT gene carriers.
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Lipid nanoparticles (LNP) have emerged as pivotal delivery vehicles for RNA therapeutics. Previous research and development usually assumed that LNPs are homogeneous in population, loading density, and composition. Such perspectives are difficult to examine due to the lack of suitable tools to characterize these physicochemical properties at the single-nanoparticle level. Here, we report an integrated spectroscopy-chromatography approach as a generalizable strategy to dissect the complexities of multicomponent LNP assembly. Our platform couples cylindrical illumination confocal spectroscopy (CICS) with single-nanoparticle free solution hydrodynamic separation (SN-FSHS) to simultaneously profile population identity, hydrodynamic size, RNA loading levels, and distributions of helper lipid and PEGylated lipid of LNPs at the single-particle level and in a high-throughput manner. Using a benchmark siRNA LNP formulation, we demonstrate the capability of this platform by distinguishing seven distinct LNP populations, quantitatively characterizing size distribution and RNA loading level in wide ranges, and more importantly, resolving composition-size correlations. This SN-FSHS-CICS analysis provides critical insights into a substantial degree of heterogeneity in the packing density of RNA in LNPs and size-dependent loading-size correlations, explained by kinetics-driven assembly mechanisms of RNA LNPs.
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Lipídeos , Nanopartículas , Tamanho da Partícula , Nanopartículas/química , Lipídeos/química , RNA/química , Cromatografia/métodos , RNA Interferente Pequeno/química , Análise Espectral/métodos , LipossomosRESUMO
BACKGROUND: Patients may use crowdfunding to solicit donations, typically from multiple small donors using internet-based means, to offset the financial toxicity of cancer care. OBJECTIVE: To describe crowdfunding campaigns by gynecologic cancer patients and to compare campaign characteristics and needs expressed between patients with cervical, uterine, and ovarian cancer. STUDY DESIGN: We queried the public crowdfunding forum GoFundMe.com for "cervical cancer," "uterine cancer," and "ovarian cancer." The first 200 consecutive posts for each cancer type fundraising within the United States were analyzed. Data on campaign goals and needs expressed were manually extracted. Descriptive statistics and bivariate analyses were performed. RESULTS: Among the 600 fundraising pages, the median campaign goal was $10,000 [IQR $5000-$23,000]. Campaigns raised a median of 28.6% of their goal with only 8.7% of campaigns reaching their goal after a median of 54 days online. On average, ovarian cancer campaigns had higher monetary goals, more donors, and larger donation amounts than cervical cancer campaigns and raised more money than both cervical and uterine cancer campaigns. Campaigns were fundraising to support medical costs (80-85%) followed by lost wages (36-56%) or living expenses (27-41%). Cervical cancer campaigns reported need for non-medical costs more frequently than uterine or ovarian cancer campaigns. States without Medicaid expansions (31% of the national population) were over-represented among cervical cancer and uterine cancer, but not ovarian cancer campaigns. CONCLUSIONS: Crowdfunding pages reveal patients fundraising for out-of-pocket costs in the thousands of dollars and a wide range of unmet financial needs based on cancer type.
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Obtenção de Fundos , Neoplasias dos Genitais Femininos , Humanos , Feminino , Obtenção de Fundos/economia , Neoplasias dos Genitais Femininos/economia , Neoplasias dos Genitais Femininos/terapia , Estados Unidos , Crowdsourcing/economia , Neoplasias do Colo do Útero/economia , Neoplasias do Colo do Útero/terapia , Neoplasias Ovarianas/economia , Neoplasias Ovarianas/terapiaRESUMO
In this study, we compared the fat-saturated (FS) and non-FS turbo spin echo (TSE) magnetic resonance imaging knee sequences reconstructed conventionally (conventional-TSE) against a deep learning-based reconstruction of accelerated TSE (DL-TSE) scans. A total of 232 conventional-TSE and DL-TSE image pairs were acquired for comparison. For each consenting patient, one of the clinically acquired conventional-TSE proton density-weighted sequences in the sagittal or coronal planes (FS and non-FS), or in the axial plane (non-FS), was repeated using a research DL-TSE sequence. The DL-TSE reconstruction resulted in an image resolution that increased by at least 45% and scan times that were up to 52% faster compared to the conventional TSE. All images were acquired on a MAGNETOM Vida 3T scanner (Siemens Healthineers AG, Erlangen, Germany). The reporting radiologists, blinded to the acquisition time, were requested to qualitatively compare the DL-TSE against the conventional-TSE reconstructions. Despite having a faster acquisition time, the DL-TSE was rated to depict smaller structures better for 139/232 (60%) cases, equivalent for 72/232 (31%) cases and worse for 21/232 (9%) cases compared to the conventional-TSE. Overall, the radiologists preferred the DL-TSE reconstruction in 124/232 (53%) cases and stated no preference, implying equivalence, for 65/232 (28%) cases. DL-TSE reconstructions enabled faster acquisition times while enhancing spatial resolution and preserving the image contrast. From these results, the DL-TSE provided added or comparable clinical value and utility in less time. DL-TSE offers the opportunity to further reduce the overall examination time and improve patient comfort with no loss in diagnostic accuracy.
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White-tailed deer, Odocoileus virginianus Zimmermann (Artiodactyla: Cervidae), are the primary wildlife host for adult stages of blacklegged ticks (Acari: Ixodidae: Ixodes scapularis Say) and an important host for lone star ticks (Acari: Ixodidae: Amblyomma americanum Linnaeus), both of which are vectors of numerous tick-borne pathogens. The 4-poster passive deer treatment device is a topical, host-targeted method to control free-living tick populations and has been proven to successfully reduce tick abundance in several states. Aggressive behavior of white-tailed deer at concentrated feeding stations is hypothesized to interfere with the effective use of 4-poster devices and deer contact with acaricide applicators. We analyzed images collected by camera traps at 4-poster feeding stations deployed at 3 sites in Maryland and found a negative relationship between some aggressive interactions and contact with applicators. Our results emphasize the need for further investigation into whether deer social dynamics can impact 4-poster efficacy for tick control. This study serves as a reminder that intraspecific interactions are important to consider when using host-targeted acaricide approaches.
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Cervos , Controle de Ácaros e Carrapatos , Infestações por Carrapato , Animais , Cervos/parasitologia , Controle de Ácaros e Carrapatos/métodos , Infestações por Carrapato/veterinária , Infestações por Carrapato/prevenção & controle , Infestações por Carrapato/parasitologia , Agressão , Ixodes/fisiologia , Acaricidas , Amblyomma , Maryland , Ixodidae/fisiologiaRESUMO
BACKGROUND: Since the beginning of the COVID-19 pandemic, older Asians have experienced a rise in racism and discrimination based on their race and ethnicity. This study examines how anti-Asian hate impacts older Asians' mental, social, and physical health. METHODS: From March 18, 2022 to January 24, 2023, we conducted a cross-sectional survey study of community-dwelling Asian/Asian American adults aged ≥50 years from the San Francisco Bay Area. Measures included perceptions of anti-Asian hate; direct encounters with hate incidents; indirect experiences with hate incidents (e.g. knowing a friend who was a victim); reports of anxiety, depression, loneliness, and changes in daily activities; ways to address these issues; and discussions with clinicians about hate incidents. RESULTS: Of the 293 older Asians, 158 (54%) were Vietnamese and 97 (33%) Chinese. Eighty-five (29%) participants were direct victims of anti-Asian hate, 112 (38%) reported anxiety, 105 (36%) reported depression, 161 (55%) reported loneliness, and 142 (48%) reported decreased daily activities. Compared with those who were "not-at-all" to "moderately" worried about hate incidents, participants who were "very" to "extremely" worried experienced heightened anxiety (42% versus 16%), loneliness (30% versus 14%), and changes in daily activities (66% versus 31%), p < 0.01 for all. Most participants (72%) felt comfortable discussing hate incidents with clinicians; however, only 31 (11%) reported that a clinician had talked with them about these incidents. CONCLUSION: Both directly and indirectly, anti-Asian hate negatively impacts older Asians' mental, social, and physical health. Clinicians have a role in addressing the health impacts of anti-Asian hate.
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Asiático , COVID-19 , Ódio , Solidão , Humanos , Masculino , Idoso , Feminino , Estudos Transversais , Asiático/psicologia , Asiático/estatística & dados numéricos , COVID-19/psicologia , COVID-19/etnologia , Pessoa de Meia-Idade , Solidão/psicologia , Racismo/psicologia , Racismo/estatística & dados numéricos , São Francisco/epidemiologia , SARS-CoV-2 , Depressão/etnologia , Depressão/psicologia , Inquéritos e Questionários , Ansiedade/psicologia , Ansiedade/etnologia , Idoso de 80 Anos ou mais , Nível de Saúde , Atividades Cotidianas/psicologiaRESUMO
BACKGROUND: The Lone Star tick, Amblyomma americanum is important to human health because of a variety of pathogenic organisms transmitted to humans during feeding events, which underscores the need to identify novel approaches to prevent tick bites. Thus, the goal of this study was to test natural and synthetic molecules for repellent activity against ticks in spatial, contact and human fingertip bioassays. METHODS: The efficacy of essential oils and naturally derived compounds as repellents to Am. americanum nymphs was compared in three different bioassays: contact, spatial and fingertip repellent bioassays. RESULTS: Concentration response curves after contact exposure to 1R-trans-chrysanthemic acid (TCA) indicated a 5.6 µg/cm2 concentration required to repel 50% of ticks (RC50), which was five- and sevenfold more active than DEET and nootkatone, respectively. For contact repellency, the rank order of repellency at 50 µg/cm2 for natural oils was clove > geranium > oregano > cedarwood > thyme > amyris > patchouli > citronella > juniper berry > peppermint > cassia. For spatial bioassays, TCA was approximately twofold more active than DEET and nootkatone at 50 µg/cm2 but was not significantly different at 10 µg/cm2. In spatial assays, thyme and cassia were the most active compounds tested with 100% and 80% ticks repelled within 15 min of exposure respectively and was approximately twofold more effective than DEET at the same concentration. To translate these non-host assays to efficacy when used on the human host, we quantified repellency using a finger-climbing assay. TCA, nootkatone and DEET were equally effective in the fingertip assay, and patchouli oil was the only natural oil that significantly repelled ticks. CONCLUSIONS: The differences in repellent potency based on the assay type suggests that the ability to discover active tick repellents suitable for development may be more complicated than with other arthropod species; furthermore, the field delivery mechanism must be considered early in development to ensure translation to field efficacy. TCA, which is naturally derived, is a promising candidate for a tick repellent that has comparable repellency to commercialized tick repellents.
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Amblyomma , Óleos Voláteis , Animais , Óleos Voláteis/farmacologia , Óleos Voláteis/química , Amblyomma/efeitos dos fármacos , Repelentes de Insetos/farmacologia , Humanos , Óleos de Plantas/farmacologia , Óleos de Plantas/química , Ninfa/efeitos dos fármacos , Bioensaio , DEET/farmacologiaRESUMO
BACKGROUND: Palliative treatment has been associated with improved quality of life and survival for a wide variety of metastatic cancers. However, it is unclear whether the benefits of palliative treatment are uniformly experienced across the US cancer population. We evaluated patterns and outcomes of palliative treatment based on socioeconomic, sociodemographic and treating facility characteristics. METHODS: Patients diagnosed between 2008 and 2019 with Stage IV primary cancer of nine organ sites were analyzed in the National Cancer Database. The association between identified variables, and outcomes concerning the administration of palliative treatment were analyzed with multivariable logistic regression and Cox proportional hazard models. RESULTS: Overall 238,995 (23.6%) of Stage IV patients received palliative treatment, which increased over time for all cancers (from 20.7% in 2008 to 25.6% in 2019). Palliative treatment utilization differed significantly by region (West less than Northeast, OR: 0.55 [0.54-0.56], p < 0.001) and insurance payer status (uninsured greater than private insurance, OR: 1.35 [1.32-1.39], p < 0.001). Black race and Hispanic ethnicity were also associated with lower rates of palliative treatment compared to White and non-Hispanics respectively (OR for Blacks: 0.91 [0.90-0.93], p < 0.001 and OR for Hispanics: 0.79 [0.77-0.81] p < 0.001). CONCLUSIONS: There are important differences in the utilization of palliative treatment across different populations in the United States. A better understanding of variability in palliative treatment use and outcomes may identify opportunities to improve informed decision making and optimize quality of care at the end-of-life.
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Neoplasias , Cuidados Paliativos , Classe Social , Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Idoso , Neoplasias/terapia , Estados Unidos , Qualidade de Vida , Adulto , Resultado do Tratamento , Estadiamento de NeoplasiasRESUMO
This qualitative study assesses the association of anti-Asian hate with older Asian individuals' health and the clinician's role in addressing hate incidents.
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Povo Asiático , Humanos , Idoso , Masculino , Feminino , Nível de SaúdeRESUMO
The latest X-ray photon-counting computed tomography (PCCT) for extremity allows multi-energy high-resolution (HR) imaging for tissue characterization and material decomposition. However, both radiation dose and imaging speed need improvement for contrast-enhanced and other studies. Despite the success of deep learning methods for 2D few-view reconstruction, applying them to HR volumetric reconstruction of extremity scans for clinical diagnosis has been limited due to GPU memory constraints, training data scarcity, and domain gap issues. In this paper, we propose a deep learning-based approach for PCCT image reconstruction at halved dose and doubled speed in a New Zealand clinical trial. Particularly, we present a patch-based volumetric refinement network to alleviate the GPU memory limitation, train network with synthetic data, and use model-based iterative refinement to bridge the gap between synthetic and real-world data. The simulation and phantom experiments demonstrate consistently improved results under different acquisition conditions on both in- and off-domain structures using a fixed network. The image quality of 8 patients from the clinical trial are evaluated by three radiologists in comparison with the standard image reconstruction with a full-view dataset. It is shown that our proposed approach is essentially identical to or better than the clinical benchmark in terms of diagnostic image quality scores. Our approach has a great potential to improve the safety and efficiency of PCCT without compromising image quality.
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Collision of a replication fork with a DNA nick is thought to generate a one-ended break, fostering genomic instability. Collision of the opposing converging fork with the nick could, in principle, form a second DNA end, enabling conservative repair by homologous recombination (HR). To study mechanisms of nickase-induced HR, we developed the Flp recombinase "step arrest" nickase in mammalian cells. Flp-nickase-induced HR entails two-ended, BRCA2/RAD51-dependent short tract gene conversion (STGC), BRCA2/RAD51-independent long tract gene conversion, and discoordinated two-ended invasions. HR induced by a replication-independent break and by the Flp-nickase differ in their dependence on BRCA1 . To determine the origin of the second DNA end during Flp-nickase-induced STGC, we blocked the opposing fork using a site-specific Tus/ Ter replication fork barrier. Flp-nickase-induced STGC remained robust and two-ended. Thus, collision of a single replication fork with a Flp-nick can trigger two-ended HR, possibly reflecting replicative bypass of lagging strand nicks. This response may limit genomic instability during replication of a nicked DNA template.
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Background: A prominent hallmark of aging is inflammaging-the increased expression of innate immune genes without identifiable infection. Model organisms with shorter lifespans, such as the fruit fly, provide an essential platform for probing the mechanisms of inflammaging. Multiple groups have reported that, like mammalian models, old flies have significantly higher levels of expression of anti-microbial peptide genes. However, whether some of these genes-or any others-can serve as reliable markers for assessing and comparing inflammaging in different strains remains unclear. Methods and Results: We compared RNA-Seq datasets generated by different groups. Although the fly strains used in these studies differ significantly, we found that they share a core group of genes with strong aging-associated expression. In addition to anti-microbial peptide genes, we identified other genes that have prominently increased expression in old flies, especially SPH93. We further showed that machine learning models can be used to predict the "inflammatory age" of the fruit y. Conclusion: A core group of genes may serve as markers for studying inflammaging in Drosophila. RNA-Seq profiles, in combination with machine-learning models, can be applied to measure the acceleration or deceleration of inflammaging.
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Insuficiência Cardíaca , Volume Sistólico , Humanos , Insuficiência Cardíaca/diagnóstico por imagem , Insuficiência Cardíaca/fisiopatologia , Volume Sistólico/fisiologia , Masculino , Feminino , Pessoa de Meia-Idade , Idoso , Imageamento por Ressonância Magnética/métodos , Meios de Contraste , Imagem Cinética por Ressonância Magnética/métodosRESUMO
The sand fly, Phlebotomus papatasi (Scopoli, 1786), is a major vector for Leishmania major in the Middle East, which has impacted human health and US military operations in the area, demonstrating the need to develop effective sand fly control and repellent options. Here, we report the results of spatial repellency and avoidance experiments in a static air olfactometer using the female P. papatasi testing essential oils of Lippia graveolens (Mexican oregano), Pimenta dioica (allspice), Amyris balsamifera (amyris), Nepeta cataria (catnip), Mentha piperita (peppermint), and Melaleuca alternifolia (tea tree); the 9-12 carbon saturated fatty acids (nonanoic acid, decanoic acid, undecanoic acid, and dodecanoic acid); and the synthetic repellents DEET and IR3535. The materials applied at 1% exhibited varying activity levels but were not significantly different in mean repellency and avoidance from DEET and IR3535, except in regards to nonanoic acid. Some materials, particularly nonanoic and undecanoic acids, produced sand fly mortality. The observed trends in mean repellency over exposure time included the following: (1) P. dioica oil, M. alternifolia oil, decanoic acid, undecanoic acid, DEET, and IR3535 exhibited increasing mean repellency over time; (2) oils of N. cataria, A. balsamifera, M. piperita, and dodecanoic acid exhibited relatively constant mean repellency over time; and (3) L. graveolens oil and nonanoic acid exhibited a general decrease in mean repellent activity over time. These studies identified the essential oils of N. cataria and A. balsamifera as effective spatial repellents at reduced concentrations compared to those of DEET. Additional research is required to elucidate the modes of action and potential synergism of repellents and essential oil components for enhanced repellency activity.
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BACKGROUND: Air pollution particulate matter exposure and chronic cerebral hypoperfusion (CCH) contribute to white matter toxicity through shared mechanisms of neuroinflammation, oxidative stress, and myelin breakdown. Prior studies showed that exposure of mice to joint particulate matter and CCH caused supra-additive injury to corpus callosum white matter. This study examines the role of TLR4 (toll-like receptor 4) signaling in mediating neurotoxicity and myelin damage observed in joint particulate matter and CCH exposures. METHODS: Experiments utilized a novel murine model of inducible monocyte/microglia-specific TLR4 knockout (i-mTLR4-ko). Bilateral carotid artery stenosis (BCAS) was induced surgically to model CCH. TLR4-intact (control) and i-mTLR4-ko mice were exposed to 8 weeks of either aerosolized diesel exhaust particulate (DEP) or filtered air (FA) in 8 experimental groups: (1) control/FA (n=10), (2) control/DEP (n=10), (3) control/FA+BCAS (n=9), (4) control/DEP+BCAS (n=10), (5) i-mTLR4-ko/FA (n=9), (6) i-mTLR4-ko/DEP (n=8), (7) i-mTLR4-ko/FA+BCAS (n=8), and (8) i-mTLR4-ko/DEP+BCAS (n=10). Corpus callosum levels of 4-hydroxynonenal, 8-Oxo-2'-deoxyguanosine, Iba-1 (ionized calcium-binding adapter molecule 1), and dMBP (degraded myelin basic protein) were assayed via immunofluorescence to measure oxidative stress, neuroinflammation, and myelin breakdown, respectively. RESULTS: Compared with control/FA mice, control/DEP+BCAS mice exhibited increased dMBP (41%; P<0.01), Iba-1 (51%; P<0.0001), 4-hydroxynonenal (100%; P<0.0001), and 8-Oxo-2'-deoxyguanosine (65%; P<0.05). I-mTLR4 knockout attenuated responses to DEP/BCAS for all markers. CONCLUSIONS: i-mTLR4-ko markedly reduced neuroinflammation and oxidative stress and attenuated white matter degradation following DEP and CCH exposures. This suggests a potential role for targeting TLR4 signaling in individuals with vascular cognitive impairment, particularly those exposed to substantial ambient air pollution.