Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 32
Filtrar
Más filtros

Bases de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Int J Mol Sci ; 23(23)2022 Nov 29.
Artículo en Inglés | MEDLINE | ID: mdl-36499303

RESUMEN

In plants, guanosine deaminase (GSDA) catalyzes the deamination of guanosine for nitrogen recycling and re-utilization. We previously solved crystal structures of GSDA from Arabidopsis thaliana (AtGSDA) and identified several novel substrates for this enzyme, but the structural basis of the enzyme activation/inhibition is poorly understood. Here, we continued to solve 8 medium-to-high resolution (1.85-2.60 Å) cocrystal structures, which involved AtGSDA and its variants bound by a few ligands, and investigated their binding modes through structural studies and thermal shift analysis. Besides the lack of a 2-amino group of these guanosine derivatives, we discovered that AtGSDA's inactivity was due to the its inability to seclude its active site. Furthermore, the C-termini of the enzyme displayed conformational diversities under certain circumstances. The lack of functional amino groups or poor interactions/geometries of the ligands at the active sites to meet the precise binding and activation requirements for deamination both contributed to AtGSDA's inactivity toward the ligands. Altogether, our combined structural and biochemical studies provide insight into GSDA.


Asunto(s)
Arabidopsis , Especificidad por Sustrato , Cristalografía por Rayos X , Dominio Catalítico , Ligandos , Guanosina/química , Sitios de Unión
2.
Am J Epidemiol ; 188(12): 2097-2109, 2019 12 31.
Artículo en Inglés | MEDLINE | ID: mdl-31602475

RESUMEN

Improvements in life expectancy among people living with human immunodeficiency virus (PLWH) receiving antiretroviral treatment in the United States and Canada might differ among key populations. Given the difference in substance use among key populations and the current opioid epidemic, drug- and alcohol-related deaths might be contributing to the disparities in life expectancy. We sought to estimate life expectancy at age 20 years in key populations (and their comparison groups) in 3 time periods (2004-2007, 2008-2011, and 2012-2015) and the potential increase in expected life expectancy with a simulated 20% reduction in drug- and alcohol-related deaths using the novel Lives Saved Simulation model. Among 92,289 PLWH, life expectancy increased in all key populations and comparison groups from 2004-2007 to 2012-2015. Disparities in survival of approximately a decade persisted among black versus white men who have sex with men and people with (vs. without) a history of injection drug use. A 20% reduction in drug- and alcohol-related mortality would have the greatest life-expectancy benefit for black men who have sex with men, white women, and people with a history of injection drug use. Our findings suggest that preventing drug- and alcohol-related deaths among PLWH could narrow disparities in life expectancy among some key populations, but other causes of death must be addressed to further narrow the disparities.


Asunto(s)
Infecciones por VIH/mortalidad , Esperanza de Vida , Modelos Teóricos , Trastornos Relacionados con Sustancias/mortalidad , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Infecciones por VIH/complicaciones , Humanos , Masculino , Persona de Mediana Edad , América del Norte/epidemiología , Trastornos Relacionados con Sustancias/complicaciones , Adulto Joven
3.
J Virol ; 91(6)2017 03 15.
Artículo en Inglés | MEDLINE | ID: mdl-28053103

RESUMEN

A subset of HIV-infected individuals termed elite controllers (ECs) maintain CD4+ T cell counts and control viral replication in the absence of antiretroviral therapy (ART). Systemic cytokine responses may differentiate ECs from subjects with uncontrolled viral replication or from those who require ART to suppress viral replication. We measured 87 cytokines in four groups of women: 73 ECs, 42 with pharmacologically suppressed viremia (ART), 42 with uncontrolled viral replication (noncontrollers [NCs]), and 48 HIV-uninfected (NEG) subjects. Four cytokines were elevated in ECs but not NCs or ART subjects: CCL14, CCL21, CCL27, and XCL1. In addition, median stromal cell-derived factor-1 (SDF-1) levels were 43% higher in ECs than in NCs. The combination of the five cytokines suppressed R5 and X4 virus replication in resting CD4+ T cells, and individually SDF-1ß, CCL14, and CCL27 suppressed R5 virus replication, while SDF-1ß, CCL21, and CCL14 suppressed X4 virus replication. Functional studies revealed that the combination of the five cytokines upregulated CD69 and CCR5 and downregulated CXCR4 and CCR7 on CD4+ T cells. The CD69 and CXCR4 effects were driven by SDF-1, while CCL21 downregulated CCR7. The combination of the EC-associated cytokines induced expression of the anti-HIV host restriction factors IFITM1 and IFITM2 and suppressed expression of RNase L and SAMHD1. These results identify a set of cytokines that are elevated in ECs and define their effects on cellular activation, HIV coreceptor expression, and innate restriction factor expression. This cytokine pattern may be a signature characteristic of HIV-1 elite control, potentially important for HIV therapeutic and curative strategies.IMPORTANCE Approximately 1% of people infected with HIV control virus replication without taking antiviral medications. These subjects, termed elite controllers (ECs), are known to have stronger immune responses targeting HIV than the typical HIV-infected subject, but the exact mechanisms of how their immune responses control infection are not known. In this study, we identified five soluble immune signaling molecules (cytokines) in the blood that were higher in ECs than in subjects with typical chronic HIV infection. We demonstrated that these cytokines can activate CD4+ T cells, the target cells for HIV infection. Furthermore, these five EC-associated cytokines could change expression levels of intrinsic resistance factors, or molecules inside the target cell that fight HIV infection. This study is significant in that it identified cytokines elevated in subjects with a good immune response against HIV and defined potential mechanisms as to how these cytokines could induce resistance to the virus in target cells.


Asunto(s)
Citocinas/metabolismo , Infecciones por VIH/inmunología , VIH/inmunología , VIH/fisiología , Replicación Viral/efectos de los fármacos , Adulto , Antígenos de Diferenciación/biosíntesis , Linfocitos T CD4-Positivos/virología , Femenino , Regulación de la Expresión Génica , Sobrevivientes de VIH a Largo Plazo , Humanos , Proteínas de la Membrana/biosíntesis , Persona de Mediana Edad , Plasma/química , Receptores del VIH/biosíntesis
4.
Nat Commun ; 15(1): 3035, 2024 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-38600088

RESUMEN

People living with HIV (PLWH) experience increased vulnerability to premature aging and inflammation-associated comorbidities, even when HIV replication is suppressed by antiretroviral therapy (ART). However, the factors associated with this vulnerability remain uncertain. In the general population, alterations in the N-glycans on IgGs trigger inflammation and precede the onset of aging-associated diseases. Here, we investigate the IgG N-glycans in cross-sectional and longitudinal samples from 1214 women and men, living with and without HIV. PLWH exhibit an accelerated accumulation of pro-aging-associated glycan alterations and heightened expression of senescence-associated glycan-degrading enzymes compared to controls. These alterations correlate with elevated markers of inflammation and the severity of comorbidities, potentially preceding the development of such comorbidities. Mechanistically, HIV-specific antibodies glycoengineered with these alterations exhibit a reduced ability to elicit anti-HIV Fc-mediated immune activities. These findings hold potential for the development of biomarkers and tools to identify and prevent premature aging and comorbidities in PLWH.


Asunto(s)
Envejecimiento Prematuro , Infecciones por VIH , Masculino , Humanos , Femenino , Inmunoglobulina G , Estudios Transversales , Envejecimiento , Inflamación/complicaciones , Polisacáridos
5.
Ann Intern Med ; 157(5): 325-35, 2012 Sep 04.
Artículo en Inglés | MEDLINE | ID: mdl-22944874

RESUMEN

BACKGROUND: The U.S. National HIV/AIDS Strategy targets for 2015 include "increasing access to care and improving health outcomes for persons living with HIV in the United States" (PLWH-US). OBJECTIVE: To demonstrate the utility of the NA-ACCORD (North American AIDS Cohort Collaboration on Research and Design) for monitoring trends in the HIV epidemic in the United States and to present trends in HIV treatment and related health outcomes. DESIGN: Trends from annual cross-sectional analyses comparing patients from pooled, multicenter, prospective, clinical HIV cohort studies with PLWH-US, as reported to national surveillance systems in 40 states. SETTING: U.S. HIV outpatient clinics. PATIENTS: HIV-infected adults with 1 or more HIV RNA plasma viral load (HIV VL) or CD4 T-lymphocyte (CD4) cell count measured in any calendar year from 1 January 2000 to 31 December 2008. MEASUREMENTS: Annual rates of antiretroviral therapy use, HIV VL, and CD4 cell count at death. RESULTS: 45 529 HIV-infected persons received care in an NA-ACCORD-participating U.S. clinical cohort from 2000 to 2008. In 2008, the 26 030 NA-ACCORD participants in care and the 655 966 PLWH-US had qualitatively similar demographic characteristics. From 2000 to 2008, the proportion of participants prescribed highly active antiretroviral therapy increased by 9 percentage points to 83% (P < 0.001), whereas the proportion with suppressed HIV VL (≤2.7 log10 copies/mL) increased by 26 percentage points to 72% (P < 0.001). Median CD4 cell count at death more than tripled to 0.209 × 109 cells/L (P < 0.001). LIMITATION: The usual limitations of observational data apply. CONCLUSION: The NA-ACCORD is the largest cohort of HIV-infected adults in clinical care in the United States that is demographically similar to PLWH-US in 2008. From 2000 to 2008, increases were observed in the percentage of prescribed HAART, the percentage who achieved a suppressed HIV VL, and the median CD4 cell count at death. PRIMARY FUNDING SOURCE: National Institutes of Health; Centers for Disease Control and Prevention; Canadian Institutes of Health Research; Canadian HIV Trials Network; and the government of British Columbia, Canada.


Asunto(s)
Antirretrovirales/uso terapéutico , Epidemias , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/epidemiología , Vigilancia de la Población , Adolescente , Adulto , Anciano , Recuento de Linfocito CD4 , Estudios Transversales , Prescripciones de Medicamentos/estadística & datos numéricos , Femenino , Infecciones por VIH/inmunología , Infecciones por VIH/virología , VIH-1/genética , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , ARN Viral/sangre , Estados Unidos/epidemiología , Carga Viral , Adulto Joven
6.
Carbon Balance Manag ; 18(1): 20, 2023 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-37728664

RESUMEN

BACKGROUND: Conducting an extensive study on the spatial heterogeneity of the overall carbon budget and its influencing factors and the decoupling status of carbon emissions from economic development, by undertaking simulation projections under different carbon emission scenarios is crucial for China to achieve its targets to peak carbon emissions by 2030 and to achieve carbon neutrality by 2060. There are large disparities in carbon emissions from energy consumption, the extent of land used for carbon absorption, and the status of decoupling of emissions from economic development, among various regions of China. RESULTS: Based on night light data and land use data, we investigated carbon budget through model estimation, decoupling analysis, and scenario simulation. The results show that the carbon deficit had a continuous upward trend from 2000 to 2018, and there was a significant positive spatial correlation. The overall status of decoupling first improved and then deteriorated. Altogether, energy consumption intensity, population density of built-up land, and built-up land area influenced the decoupling of carbon emissions from economic development. There are significant scenarios of carbon emissions from energy consumption for the study area during the forecast period, only in the low-carbon scenario will the study area reach the expected carbon emissions peak ahead of schedule in 2027; the peak carbon emissions will be 6479.27 million tons. CONCLUSIONS: China's provincial-scale carbon emissions show a positive correlation with economic development within the study period. It is necessary to optimize the economic structure, transforming the economic development mode, and formulating policies to control the expansion of built-up land. Efforts must be made to improve technology and promote industrial restructuring, to effectively reduce energy consumption intensity.

7.
MethodsX ; 10: 102146, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37025652

RESUMEN

Measures of viremic exposure over time, including HIV viral copy-years or durable viremic suppression, may be more relevant measures of viral load exposure for comorbid outcomes and mortality than single time point viral load measures. However, there are many subjective decisions that go into creating a cumulative variable such as HIV viral copy-years, including the appropriate anchoring point to begin accumulating exposure, the handling of viral load levels below an assay's lower limit of detection (LLD), the handling of gaps in the viral load trajectory, and when to apply the log10 transformation (before or after the accumulation calculation). Different decisions produce different values for HIV viral copy-years, and such differences could impact inferences in subsequent analyses of relationships with outcomes. In this paper, we develop several HIV viral copy-years variables that are standardized across:•Anchoring point•Handling of viral loads measured below the LLD and missing viral load measures•Application of the log10 transformation. These standardized variables may be consistently used in analyses of longitudinal cohort data. We also define a supplementary dichotomous HIV viral load exposure variable that may be used in tandem, or alternatively to, the HIV viral copy-years variables.

8.
Artículo en Inglés | MEDLINE | ID: mdl-36673979

RESUMEN

Soil erosion is an important global environmental issue that severely affects regional ecological environment and socio-economic development. The Yellow River (YR) is China's second largest river and the fifth largest one worldwide. Its watershed is key to China's economic growth and environmental security. In this study, six impact factors, including rainfall erosivity (R), soil erosivity (K), slope length (L), slope steepness (S), cover management (C), and protective measures (P), were used. Based on the revised universal soil loss equation (RUSLE) model, and combined with a geographic information system (GIS), the temporal and spatial distribution of soil erosion (SE) in the YR from 2000 to 2020 was estimated. The patch-generating land use simulation (PLUS) model was used to simulate the land-use and land-cover change (LUCC) under two scenarios (natural development and ecological protection) in 2040; the RUSLE factor P was found to be associated with LUCC in 2040, and soil erosion in the Yellow River Basin (YRB) in 2040 under the two scenarios were predicted and evaluated. This method has great advantages in land-use simulation, but soil erosion is greatly affected by rainfall and slope, and it only focuses on the link between land-usage alteration and SE. Therefore, this method has certain limitations in assessing soil erosion by simulating and predicting land-use change. We found that there is generally slight soil erosivity in the YRB, with the most serious soil erosion occurring in 2000. Areas with serious SE are predominantly situated in the upper reaches (URs), followed by the middle reaches (MRs), and soil erosion is less severe in the lower reaches. Soil erosion in the YRB decreased 11.92% from 2000 to 2020; thus, soil erosion has gradually reduced in this area over time. Based on the GIS statistics, land-use change strongly influences SE, while an increase in woodland area has an important positive effect in reducing soil erosion. By predicting land-use changes in 2040, compared to the natural development scenario, woodland and grassland under the ecological protection scenario can be increased by 1978 km2 and 2407 km2, respectively. Soil erosion can be decreased by 6.24%, indicating the implementation of woodland and grassland protection will help reduce soil erosion. Policies such as forest protection and grassland restoration should be further developed and implemented on the MRs and URs of the YR. Our research results possess important trend-setting significance for soil erosion control protocols and ecological environmental protection in other large river basins worldwide.


Asunto(s)
Ríos , Suelo , Erosión del Suelo , Modelos Teóricos , Monitoreo del Ambiente/métodos , Conservación de los Recursos Naturales
9.
Comput Struct Biotechnol J ; 21: 5515-5522, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38022696

RESUMEN

Guanosine deaminase (GSDA) is an important deaminase that converts guanosine to xanthosine, a key intermediate in nitrogen recycling in plants. We previously solved complex structures of Arabidopsis thaliana GSDA bound by various ligands and examined its catalytic mechanism. Here, we report cocrystal structures of AtGSDA bound by inactive guanosine derivatives, which bind relatively weakly to the enzyme and mostly have poor binding geometries. The two protomers display unequal binding performances, and molecular dynamics simulation identified diverse conformations during the enzyme-ligand interactions. Moreover, intersubunit, tripartite salt bridges show conformational differences between the two protomers, possibly acting as "gating" systems for substrate binding and product release. Our structural and biochemical studies provide a comprehensive understanding of the enzymatic behavior of this intriguing enzyme.

10.
JAMA Netw Open ; 6(11): e2344194, 2023 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-38019518

RESUMEN

Importance: Blood-based biomarkers associated with increased risk of Alzheimer disease (AD) are understudied in people living with and without HIV, particularly women. Objective: To determine whether baseline or 1-year changes in plasma amyloid-ß40 (Aß40), Aß42, ratio of Aß42 to Aß40, total tau (t-tau), phosphorylated tau 231 (p-tau231), glial fibrillary acidic protein (GFAP), and/or neurofilament light chain (NFL) are associated with neuropsychological performance (NP) among women living with HIV (WLWH) and women living without HIV (WLWOH). Design, Setting, and Participants: This longitudinal, prospective, cohort study with 1-year repeated clinical measures (NP only measured once) and biospecimen collection occurred between 2017 and 2019. Participants were women aged 40 years or older from 10 clinical research sites in cities across the US that were part of the Women's Interagency HIV Study. Data analysis was conducted from April to December 2022. Exposure: Laboratory-confirmed HIV status and AD biomarkers. Main Outcomes and Measures: Sociodemographically adjusted NP T-scores (attention and working memory, executive function, processing speed, memory, learning, verbal fluency, motor function, and global performance) were the primary outcomes. Baseline and 1-year fasting plasma Aß40, Aß42, t-tau, p-tau231, GFAP, and NFL levels were measured and analyzed using multivariable linear regression. Results: The study consisted of 307 participants (294 aged ≥50 years [96%]; 164 African American or Black women [53%]; 214 women with a high school education or higher [70%]; 238 women who were current or former smokers [78%]; and 236 women [77%] who were overweight or obese [body mass index >25]) including 209 WLWH and 98 WLWOH. Compared with WLWOH at baseline, WLWH performed worse on learning (mean [SD] T-score 47.8 [11.3] vs 51.4 [10.5]), memory (mean [SD] T-score 48.3 [11.6] vs 52.4 [10.2]), verbal fluency (mean [SD] T-score 48.3 [9.8] vs 50.7 [8.5]), and global (mean [SD] T-score 49.2 [6.8] vs 51.1 [5.9]) NP assessments. Baseline median Aß40, GFAP, and NFL levels were higher among WLWH vs WLWOH. There were no differences in 1-year biomarker change by HIV serostatus. Lower learning, memory, and motor NP were associated with 1-year Aß40 increase; lower learning and motor with Aß42 increase; lower motor with p-tau231 increase; and lower processing speed, verbal fluency and motor with NFL increase in the entire sample. Among WLWH, a 1-year increase in Aß40 from baseline to follow-up was associated with worse learning, memory, and global NP; a 1-year increase in t-tau with worse executive function; and a 1-year increase in NFL with worse processing speed. Among WLWOH, a 1-year increase in Aß40 and Aß42 were associated with poorer memory performance and NFL was associated with poorer motor performance. Conclusions and Relevance: These findings suggest that increases in certain plasma AD biomarkers are associated with NP in WLWH and WLWOH and may be associated with later onset of AD, and measuring these biomarkers could be a pivotal advancement in monitoring aging brain health and development of AD among women with and without HIV.


Asunto(s)
Enfermedad de Alzheimer , Infecciones por VIH , Femenino , Humanos , Masculino , Estudios de Cohortes , Estudios Prospectivos , Biomarcadores , Infecciones por VIH/complicaciones
11.
bioRxiv ; 2023 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-37609144

RESUMEN

People with HIV (PWH) experience an increased vulnerability to premature aging and inflammation-associated comorbidities, even when HIV replication is suppressed by antiretroviral therapy (ART). However, the factors that contribute to or are associated with this vulnerability remain uncertain. In the general population, alterations in the glycomes of circulating IgGs trigger inflammation and precede the onset of aging-associated diseases. Here, we investigate the IgG glycomes of cross-sectional and longitudinal samples from 1,216 women and men, both living with virally suppressed HIV and those without HIV. Our glycan-based machine learning models indicate that living with chronic HIV significantly accelerates the accumulation of pro-aging-associated glycomic alterations. Consistently, PWH exhibit heightened expression of senescence-associated glycan-degrading enzymes compared to their controls. These glycomic alterations correlate with elevated markers of inflammatory aging and the severity of comorbidities, potentially preceding the development of such comorbidities. Mechanistically, HIV-specific antibodies glycoengineered with these alterations exhibit reduced anti-HIV IgG-mediated innate immune functions. These findings hold significant potential for the development of glycomic-based biomarkers and tools to identify and prevent premature aging and comorbidities in people living with chronic viral infections.

12.
J Infect Dis ; 204(6): 893-901, 2011 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-21849286

RESUMEN

BACKGROUND: Screening for tuberculosis prior to highly active antiretroviral therapy (HAART) initiation is not routinely performed in low-incidence settings. Identifying factors associated with developing tuberculosis after HAART initiation could focus screening efforts. METHODS: Sixteen cohorts in the United States and Canada contributed data on persons infected with human immunodeficiency virus (HIV) who initiated HAART December 1995-August 2009. Parametric survival models identified factors associated with tuberculosis occurrence. RESULTS: Of 37845 persons in the study, 145 were diagnosed with tuberculosis after HAART initiation. Tuberculosis risk was highest in the first 3 months of HAART (20 cases; 215 cases per 100000 person-years; 95% confidence interval [CI]: 131-333 per 100000 person-years). In a multivariate Weibull proportional hazards model, baseline CD4+ lymphocyte count <200, black race, other nonwhite race, Hispanic ethnicity, and history of injection drug use were independently associated with tuberculosis risk. In addition, in a piece-wise Weibull model, increased baseline HIV-1 RNA was associated with increased tuberculosis risk in the first 3 months; male sex tended to be associated with increased risk. CONCLUSIONS: Screening for active tuberculosis prior to HAART initiation should be targeted to persons with baseline CD4 <200 lymphocytes/mm³ or increased HIV-1 RNA, persons of nonwhite race or Hispanic ethnicity, history of injection drug use, and possibly male sex.


Asunto(s)
Fármacos Anti-VIH/administración & dosificación , Terapia Antirretroviral Altamente Activa/métodos , Infecciones por VIH/complicaciones , Infecciones por VIH/tratamiento farmacológico , Tuberculosis/epidemiología , Adulto , Canadá/epidemiología , Femenino , Infecciones por VIH/virología , VIH-1/aislamiento & purificación , Humanos , Masculino , Persona de Mediana Edad , Factores de Riesgo , Tuberculosis/diagnóstico , Estados Unidos/epidemiología
13.
J Phys Chem B ; 126(19): 3585-3592, 2022 05 19.
Artículo en Inglés | MEDLINE | ID: mdl-35543216

RESUMEN

Compared with univalent cationic diffusion, little is known about the diffusion behavior of multivalent cations let alone the diffusion of water in their first hydration shell. Here, we show that all published translational diffusion coefficients of multivalent cations and water measured at room temperature exhibit the same concentration dependence when plotted as a function of the mass fraction of free water or of hydrated solute. This behavior is held until only hydration and confined water remain in solutions, wherein their concentration dependences become cationic charge number-dependent. We also found that the iceberg model can well describe the diffusions of multivalent cations with decreasing water content until only hydration water is present. However, 1H-pulsed-field-gradient nuclear magnetic resonance measurements confirmed that 1H in the first hydration shell diffuses faster than Al3+ at room temperature and they have the same diffusion coefficient only with decreasing the temperature down to about 243 K. Therefore, iceberg model only equivalently describes the effect of strong ion-water interaction on multivalent cationic diffusion. These results will also help us reconceive our current understanding of the pathway for hydration water affecting the diffusion behavior of solutes with relatively weak solute-water interactions.


Asunto(s)
Cationes/química , Soluciones/química , Agua , Difusión , Temperatura
14.
PLoS One ; 17(3): e0262540, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35358194

RESUMEN

Climate is a dominant factor affecting the potential geographical distribution of species. Understanding the impact of climate change on the potential geographic distribution of species, which is of great significance to the exploitation, utilization, and protection of resources, as well as ecologically sustainable development. Betula platyphylla Suk. is one of the most widely distributed temperate deciduous tree species in East Asia and has important economic and ecological value. Based on 231 species distribution data points of Betula platyphylla Suk. in China and 37 bioclimatic, soil, and topography variables (with correlation coefficients < 0.75), the potential geographical distribution pattern of Betula platyphylla Suk. under Representative Concentration Pathway (RCP) climate change scenarios at present and in the 2050s and 2070s was predicted using the MaxEnt model. We analyzed the main environmental variables affecting the distribution and change of suitable areas and compared the scope and change of suitable areas under different climate scenarios. This study found: (1) At present, the main suitable area for Betula platyphylla Suk. extends from northeastern to southwestern China, with the periphery area showing fragmented distribution. (2) Annual precipitation, precipitation of the warmest quarter, mean temperature of the warmest quarter, annual mean temperature, and precipitation of the driest month are the dominant environmental variables that affect the potential geographical distribution of Betula platyphylla Suk. (3) The suitable area for Betula platyphylla Suk. is expected to expand under global warming scenarios. In recent years, due to the impact of diseases and insect infestation, and environmental damage, the natural Betula platyphylla Suk. forest in China has gradually narrowed. This study accurately predicted the potential geographical distribution of Betula platyphylla Suk. under current and future climate change scenarios, which can provide the scientific basis for the cultivation, management, and sustainable utilization of Betula platyphylla Suk. resources.


Asunto(s)
Cambio Climático , Ecosistema , Betula , China
15.
Ann Epidemiol ; 65: 46-55, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34627998

RESUMEN

BACKGROUND: The age-distribution of men who have sex with men (MSM) continues to change in the 'Treat-All' era as effective test-and-treat programs target key-populations. However, the nature of these changes and potential racial heterogeneities remain uncertain. METHODS: The PEARL model is an agent-based simulation of MSM in HIV care in the US, calibrated to data from the North American AIDS Cohort Collaboration on Research and Design (NA-ACCORD). RESULTS: PEARL projects a gradual decrease in median age of MSM at ART initiation from 36 to 31 years during 2010-2030, accompanied by changes in mortality among Black, White, and Hispanic MSM on ART by -8.4%, 42.4% and -19.6%. The median age of all MSM on ART is projected to increase from 45 to 47 years from 2010-2030, with the proportion of ART-users age ≥60y increasing from 6.7% to 28.0%. Almost half (49.7%) of White MSM ART-users are projected to age ≥60y by 2030, compared to 19.5% of Black and 17.2% of Hispanic MSM. CONCLUSIONS: The overall age of US MSM in HIV care is expected to increase over the next decade, and differentially by race/ethnicity. As this population age, HIV programs should expand care for age-related causes of morbidity and mortality.


Asunto(s)
Infecciones por VIH , Minorías Sexuales y de Género , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/epidemiología , Hispánicos o Latinos , Homosexualidad Masculina , Humanos , Masculino , Persona de Mediana Edad , Grupos Raciales , Estados Unidos/epidemiología
16.
J Acquir Immune Defic Syndr ; 91(5): 469-478, 2022 12 15.
Artículo en Inglés | MEDLINE | ID: mdl-36053091

RESUMEN

BACKGROUND: We characterized trends in statin eligibility and subsequent statin initiation among people with HIV (PWH) from 2001 to 2017 and identified predictors of statin initiation between 2014 and 2017. SETTING: PWH participating in the North American AIDS Cohort Collaboration on Research and Design (NA-ACCORD) enrolled in 12 US cohorts collecting data on statin eligibility criteria/prescriptions from 2001 to 2017. METHODS: We determined the annual proportion eligible for statins, initiating statins, and median waiting time (from statin eligibility to initiation). Eligibility was defined using ATP III guidelines (2001-2013) and ACC/AHA guidelines (2014-2017). We assessed initiation predictors in 2014-2017 among statin-eligible PWH using Poisson regression, estimating adjusted prevalence ratios (aPRs) with 95% confidence intervals (95% CIs). RESULTS: Among 16,409 PWH, 7386 (45%) met statin eligibility criteria per guidelines (2001-2017). From 2001 to 2013, statin eligibility ranged from 22% to 25%. Initiation increased from 13% to 45%. In 2014, 51% were statin-eligible, among whom 25% initiated statins, which increased to 32% by 2017. Median waiting time to initiation among those we observed declined over time. Per 10-year increase in age, initiation increased 46% (aPR 1.46, 95% CI: 1.29 to 1.67). Per 1-year increase in calendar year from 2014 to 2017, there was a 41% increase in the likelihood of statin initiation (aPR 1.41, 95% CI: 1.25 to 1.58). CONCLUSIONS: There is a substantial statin treatment gap, amplified by the 2013 ACC/AHA guidelines. Measures are warranted to clarify reasons we observe this gap, and if necessary, increase statin use consistent with guidelines including efforts to help providers identify appropriate candidates.


Asunto(s)
Enfermedades Cardiovasculares , Infecciones por VIH , Inhibidores de Hidroximetilglutaril-CoA Reductasas , Adulto , Humanos , Inhibidores de Hidroximetilglutaril-CoA Reductasas/uso terapéutico , Enfermedades Cardiovasculares/epidemiología , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/epidemiología , Determinación de la Elegibilidad , Grupos Raciales
17.
AIDS ; 36(3): 459-471, 2022 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-34750289

RESUMEN

OBJECTIVE: To project the future age distribution of people with HIV using antiretroviral therapy (ART) in the United States, under expected trends in HIV diagnosis and survival (baseline scenario) and achieving the ending the HIV epidemic (EHE) goals of a 75% reduction in HIV diagnoses from 2020 to 2025 and sustaining levels to 2030 (EHE75% scenario). DESIGN: An agent-based simulation model with mathematical functions estimated from North American AIDS Cohort Collaboration on Research and Design data and parameters from the US Centers for Disease Control and Prevention's annual HIV surveillance reports. METHODS: The PEARL (ProjEcting Age, MultimoRbidity, and PoLypharmacy in adults with HIV) model simulated individuals in 15 subgroups of sex-and-HIV acquisition risk and race/ethnicity. Simulation outcomes from the baseline scenario are compared with outcomes from the EHE75% scenario. RESULTS: Under the baseline scenario, PEARL projects a substantial increase in number of ART-users over time, reaching a population of 909 638 [95% uncertainty range (UR): 878 449-946 513] by 2030. The overall median age increased from 50 years in 2020 to 52 years in 2030, with 23% of ART-users age ≥65 years in 2030. Under the EHE75% scenario, the projected number of ART-users was 718 348 [703 044-737 817] (median age = 56 years) in 2030, with a 70% relative reduction in ART-users <30 years and a 4% relative reduction in ART-users age ≥65 years compared to baseline, and persistent heterogeneities in projected numbers by sex-and-HIV acquisition risk group and race/ethnicity. CONCLUSIONS: It is critical to prepare healthcare systems to meet the impending demand of the US population aging with HIV.


Asunto(s)
Epidemias , Infecciones por VIH , Adulto , Distribución por Edad , Anciano , Estudios de Cohortes , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/epidemiología , Humanos , Persona de Mediana Edad , Factores de Riesgo , Estados Unidos/epidemiología
18.
Am J Epidemiol ; 174(6): 727-35, 2011 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-21813792

RESUMEN

Determination of the prevalence of accumulated antiretroviral drug resistance among persons infected with human immunodeficiency virus (HIV) is complicated by the lack of routine measurement in clinical care. By using data from 8 clinic-based cohorts from the North American AIDS Cohort Collaboration on Research and Design, drug-resistance mutations from those with genotype tests were determined and scored using the Genotypic Resistance Interpretation Algorithm developed at Stanford University. For each year from 2000 through 2005, the prevalence was calculated using data from the tested subset, assumptions that incorporated clinical knowledge, and multiple imputation methods to yield a complete data set. A total of 9,289 patients contributed data to the analysis; 3,959 had at least 1 viral load above 1,000 copies/mL, of whom 2,962 (75%) had undergone at least 1 genotype test. Using these methods, the authors estimated that the prevalence of accumulated resistance to 2 or more antiretroviral drug classes had increased from 14% in 2000 to 17% in 2005 (P < 0.001). In contrast, the prevalence of resistance in the tested subset declined from 57% to 36% for 2 or more classes. The authors' use of clinical knowledge and multiple imputation methods revealed trends in HIV drug resistance among patients in care that were markedly different from those observed using only data from patients who had undergone genotype tests.


Asunto(s)
Fármacos Anti-VIH/uso terapéutico , Farmacorresistencia Viral Múltiple , Infecciones por VIH/tratamiento farmacológico , VIH-1/efectos de los fármacos , Medición de Riesgo/estadística & datos numéricos , Adulto , Femenino , Estudios de Seguimiento , Genotipo , Infecciones por VIH/epidemiología , Infecciones por VIH/virología , VIH-1/genética , Humanos , Masculino , Persona de Mediana Edad , Mutación , América del Norte/epidemiología , Prevalencia , ARN Viral/genética , Estudios Retrospectivos , Factores de Tiempo
19.
J Phys Chem B ; 125(47): 13041-13048, 2021 Dec 02.
Artículo en Inglés | MEDLINE | ID: mdl-34788045

RESUMEN

Here, we report a new state-diagram for aqueous solutions based on concentration-dependent glass-transition temperatures of concentrated and ice freeze-concentrated solutions. Different from the equilibrium phase diagram, this new state-diagram can provide comprehensive information about the hydration numbers of solutes, nonequilibrium vitrification/cold-crystallization, and vitrification/devitrification processes of aqueous solutions in three distinct concentration zones separated by two critical water-content points of only functions of the hydration number. Based on this new state-diagram, we observe the comparable hydration ability of LiTFSI to LiCl and an atypical concentration-dependent cold-crystallization behavior of the LiTFSI-H2O system. These results unveil the negligible hydration ability of TFSI- in a water-rich solution, characterize the antiplasticizing effect of water induced by the strengthened Li+-TFSI--H2O interaction when only hydration water and confined water are present, and confirm the increasing fraction of water-rich domains with the decrease in water content when the cation and anion become incompletely hydrated on average. These results highlight the novel water-content-mediated interactions among the anion, cation, and H2O for LiTFSI-H2O.

20.
Insects ; 12(7)2021 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-34357261

RESUMEN

Spodoptera litura F. is a generalist herbivore and one of the most important economic pests feeding on about 300 host plants in many Asian countries. Specific insect behaviors can be stimulated after recognizing chemicals in the external environment through conserved chemosensory proteins (CSPs) in chemoreceptive organs, which are critical components of the olfactory systems. To explore its structural basis for ligand-recognizing capability, we solved the 2.3 Å crystal structure of the apoprotein of S. litura CSP8 (SlCSP8). The SlCSP8 protein displays a conserved spherical shape with a negatively charged surface. Our binding assays showed that SlCSP8 bound several candidate ligands with differential affinities, with rhodojaponin III being the most tightly bound ligand. Our crystallographic and biochemical studies provide important insight into the molecular recognition mechanism of the sensory protein SlCSP8 and the CSP family in general, and they suggest that CSP8 is critical for insects to identify rhodojaponin III, which may aid in the CSP-based rational drug design in the future.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA