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1.
J Contam Hydrol ; 261: 104298, 2024 02.
Artigo em Inglês | MEDLINE | ID: mdl-38242064

RESUMO

Groundwater contamination at legacy uranium processing sites is an ongoing global challenge. Plumes at many uranium-contaminated sites are more persistent than originally predicted by groundwater modeling. Previous investigations of uranium plume persistence identified residual and secondary sources that contribute to plume longevity, but there is a remaining need to revise forecasted cleanup times using information about these ongoing sources. The purpose of this study is to investigate the quantitative impact of residual vadose zone sources of uranium on groundwater remediation time frame. This objective was approached by applying numerical uranium transport simulations and uncertainty analysis to a former uranium mill site in the southwestern United States. Information from recent site investigations provided details about the distribution and release characteristics of uranium accumulations in the vadose zone. The residual uranium characteristics were incorporated as decaying source terms in the transport model. A stochastic approach using an iterative ensemble smoother was applied for history matching, and the transport model was used to assess the impact of multiple remedial alternatives on forecasted time frame. The forecasted time frame to achieve the groundwater remediation goal for uranium by monitored natural attenuation is on the order of thousands of years, and treatment of the dissolved plume does not reduce the projected time frame. The large proportion of residual uranium mass remaining in the vadose zone and the gradual leaching rate due to the site's semiarid climate create a long-lived source that can sustain a dissolved plume for thousands of years despite an estimated 99% mass removal achieved during mill tailings disposal. Residual uranium in vadose zone sediments beneath former tailings impoundments could present comparable uranium plume persistence and remediation challenges at other legacy uranium mill sites in semiarid climates. Other remaining uranium-impacted sites are similarly complex, and forecasted remedial time frames are needed to effectively achieve compliance, manage risk, assess the benefits of additional treatment, manage and project costs, and support beneficial site reuse.


Assuntos
Água Subterrânea , Urânio , Poluentes Radioativos da Água , Urânio/análise , Poluentes Radioativos da Água/análise
2.
Front Med (Lausanne) ; 10: 1189666, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37275365

RESUMO

Purpose: The Association of American Medical Colleges' (AAMC) Strategic Plan lists 10 action plans one of which is focused on understanding how systemic barriers, such as racism and access to quality education, may negatively impact diversity in academic medicine. Thus, the purpose of this study was to understand the factors that impact the matriculation and persistence of Black medical students. Method: A qualitative phenomenological study using Tinto's Model of Institutional Departure as an organizing framework was used for this study. Participants were asked a series of questions covering topics related to their goals, their medical school experience, their preparation for medical school, what could improve their medical school experience, and advice for future Black medical students. Results: Forty in-depth semi-structured interviews were conducted during the fall 2022 term from October to December with Black medical students enrolled in over 16 US or Caribbean medical schools. Findings reported that two factors impacted matriculation for Black medical students (exposure to the medical field and resources, particularly financial resources). Findings also reported that three factors impacted the persistence of Black students once in medical school (diversity, support, and emotional resources). Conclusion: The five factors identified by participants that impact matriculation and persistence for Black medical students can be used by medical schools to increase their enrollment and graduation of Black students.

3.
J Contam Hydrol ; 251: 104076, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36148719

RESUMO

The recharge of stream water below the baseflow water table can mobilize groundwater contaminants, particularly redox-sensitive and sorptive metals such as uranium. However, in-situ tracer experiments that simulate the recharge of stream water to uranium-contaminated groundwater are lacking, thus limiting the understanding of the potential mechanisms that control the mobility of uranium at the field scale. In this study, a field tracer test was conducted by injecting 100 gal (379 l) of oxic river water into a nearby suboxic and uranium-contaminated aquifer. The traced river water was monitored for 18 days in the single injection well and in the twelve surrounding observation wells. Mobilization of uranium from the solid to the aqueous phase was not observed during the tracer test despite its pre-test presence being confirmed on the aquifer sediments from lab-based acid leaching. However, strong evidence of oxidative immobilization of iron and manganese was observed during the tracer test and suggested that immobile uranium was likely in its oxidized state as U(VI) on the aquifer sediments; these observations ruled out oxidation of U(IV) to U(VI) as a potential mobilization mechanism. Therefore, desorption of U(VI) appeared to be the predominant potential mobilization mechanism, yet it was clearly not solely dependent on concentration as evident when considering that uranium-poor river water (<0.015 mg/L) was recharged to uranium-rich groundwater (≈1 mg/L). It was possible that uranium desorption was limited by the relatively higher pH and lower alkalinity of the river water as compared to the groundwater; both factors favor immobilization. However, it was likely that the immobile uranium was associated with a mineral phase, as opposed to a sorbed phase, thus desorption may not have been possible. The results of this field tracer study successfully ruled out two common mobilization mechanisms of uranium: (1) oxidative dissolution and (2) concentration-dependent desorption and ruled in the importance of advection, dispersion, and the mineral phase of uranium.


Assuntos
Água Subterrânea , Urânio , Poluentes Radioativos da Água , Urânio/análise , Poluentes Radioativos da Água/análise , Rios , Minerais , Água , Sedimentos Geológicos
4.
Ground Water ; 60(4): 565-570, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35156199

RESUMO

A simple algebraic equation is presented here to estimate the magnitude of groundwater velocity based on data from a single-well injection-drift test thereby eliminating the time-consuming and costly extraction phase. A volume of tracer-amended water was injected by forced-gradient into a single well followed by monitoring of the conservative solute tracers under natural-gradient conditions as their upgradient portions drifted back through the well. The breakthrough curve data from the single well during the drift phase was analyzed to determine the mean travel times of the tracers. The estimated mean upgradient travel distance back through the single well and the mean travel times of the tracers were used in a simple algebraic equation to estimate groundwater velocity. The groundwater velocity based on the single-well injection-drift test was estimated to be approximately 0.64 ft per day. Two transects of observation wells were used to monitor the natural-gradient tracer transport downgradient of the injection well. The one-dimensional, or dual-well, transport of the tracer from the injection well to the nearest downgradient observation well indicated that the groundwater velocity was 0.55 ft per day. The two-dimensional, or multi-well, transport of the center of mass of the tracers indicated that the groundwater velocity was 0.60 ft per day; the dual- and multi-well results were in excellent agreement with those from the single-well and validated the simple algebraic equation. The new single-well method presented here is relatively simple, rapid, and does not require an extraction phase.


Assuntos
Água Subterrânea , Água , Movimentos da Água , Poços de Água
5.
J Infect Dis ; 225(11): 2033-2042, 2022 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-35172331

RESUMO

Chlamydia trachomatis serovars A-L cause important diseases of the eyes and reproductive tract by infecting epithelium lining those organs. A major hurdle for vaccine trials is finding a surrogate biomarker for protective immunity. Investigational data argues for T-cell biomarker(s) reflecting mucosal adaption, cytokine polarization, B-cell help, antibacterial effector mechanisms, or some combination thereof. A human investigation and 2 mouse studies link IL-13 to protection from infection/immunopathology. We performed RNAseq on T cells resident in spleens and genital tracts of naturally immune mice. CD4 signatures were consistent with helper function that differed by site including a genital tract-specific Fgl2 signal. The genital tract CD8 signature featured IL-10 and promotion of healing/scarring with a unique transcription of granzyme A. The RNAseq data was used to refine previously published CD4γ13 and CD8γ13 transcriptomes derived from protective T-cell clones, potentially identifying practicable T-cell subset signatures for assessing Chlamydia vaccine candidates.


Assuntos
Infecções por Chlamydia , Animais , Linfócitos B , Linfócitos T CD4-Positivos , Infecções por Chlamydia/microbiologia , Chlamydia trachomatis , Genitália/patologia , Camundongos , Camundongos Endogâmicos C57BL , Subpopulações de Linfócitos T
6.
J Environ Manage ; 277: 111416, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33039703

RESUMO

The many uses of palladium in medicine, catalysts and other industries make it a very important precious element. Many industries using palladium discharge process wastewaters that may release elevated concentrations of palladium into the environment. This study focused on the recovery of palladium from aqueous solutions by zeolite functionalised with spent brewer's yeast. Batch experimental results were used to calibrate a generalised surface complexation model based on coupling parameter estimation (PEST) to the PHREEQC geochemical modelling code. PHREEQC is an acronym which stands for pH, redox, equilibrium and C programming language. Calibration was based on the determination of sorption constants for the reactions of palladium with the adsorbent. The generalised amine surface groups (derived from yeast), the moles of adsorption sites and surface area were specified. The recovery of palladium was assessed as a function of solution pH, adsorbent dosage and initial concentration of palladium in the presence of other cations and anions at different concentrations. The highest recovery of palladium (>97%) was observed at pH 2 and 10 g L-1 adsorbent dosage which, decreased with increasing solution pH. The amount of palladium removed increased in the presence of competing ions and anions. There was no significant difference (p > 0.05) between the modelled and measured data, which indicated that PHREEQC modelling code coupled with PEST can accurately determine the recovery of palladium using amine-based adsorbents when all the required information is specified. This is very useful in instances where limited experimental data is available for non-conventional and novel surfaces to make accurate predictions of sorption processes involving them.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Zeolitas , Adsorção , Aminas , Concentração de Íons de Hidrogênio , Cinética , Paládio
9.
Vaccine ; 38(16): 3280-3291, 2020 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-32151463

RESUMO

The Chlamydial outer membrane complex (COMC) from the elementary body (EB) is a protein rich insoluble outer membrane shell from which cytosolic proteins have been extracted with detergent. In this study we conducted mass spectrometry experiments to detect proteins in the COMC prepared from C. muridarum EB. Proteomic analysis showed that the COMC contained 75 proteins that included 10 outer membrane proteins (OMPs) such as the major outer membrane protein (MOMP) and polymorphic membrane proteins (Pmps) that were previously identified as CD4 T cell vaccine candidates. We tested the vaccine efficacy of COMC in comparison to individual or combination of recombinant OMPs formulated with Th1 polarizing adjuvant DDA/MPL in two murine genital tract models (C. muridarum and C. trachomatis) by measuring organismal shedding, tubal pathology and immune responses including neutralizing antibodies. In the C. muridarum model, the COMC vaccine generated broadly reactive immune responses against multiple outer membrane proteins, high levels of EB binding and neutralizing antibody and exhibited superior protection against genital infection and pathology when compared to the recombinant PmpG vaccine. Denaturing the COMC by boiling significantly reduced protection. In the C. trachomatis model, the COMC vaccine also conferred greater protection compared to individual or multiple recombinant outer membrane proteins. Immunization with multiple COMCs from C. trachomatis serovars D, F and J generated neutralizing antibodies against multiple C. trachomatis serovars. We conclude that broader immunogenicity and generation of neutralizing antibody may explain the superior efficacy of COMC vaccine. The study suggests that conformationally intact proteins will be necessary for a successful recombinant OMP vaccine.


Assuntos
Infecções por Chlamydia , Chlamydia muridarum , Animais , Anticorpos Antibacterianos , Proteínas da Membrana Bacteriana Externa/genética , Vacinas Bacterianas , Infecções por Chlamydia/prevenção & controle , Chlamydia trachomatis , Camundongos , Proteômica
10.
J Infect Dis ; 221(11): 1895-1906, 2020 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-31899500

RESUMO

BACKGROUND: The T-cell response to chlamydia genital tract infections in humans and mice is unusual because the majority of antigen-specific CD8 T cells are not class I restricted (referred to here as "unrestricted" or "atypical"). We previously reported that a subset of unrestricted murine chlamydia-specific CD8 T cells had a cytokine polarization pattern that included interferon (IFN)-γ and interleukin (IL)-13. METHODS: In this study, we investigated the transcriptome of CD8γ13 T cells, comparing them to Tc1 clones using microarray analysis. That study revealed that CD8γ13 polarization included IL-5 in addition to IFN-γ and IL-13. Adoptive transfer studies were performed with Tc1 clones and a CD8γ13 T-cell clone to determine whether either influenced bacterial clearance or immunopathology during Chlamydia muridarum genital tract infections. RESULTS: To our surprise, an adoptively transferred CD8γ13 T-cell clone was remarkably proficient at preventing chlamydia immunopathology, whereas the multifunctional Tc1 clone did not enhance clearance or significantly alter immunopathology. Mapping studies with major histocompatibility complex (MHC) class I- and class II-deficient splenocytes showed our previously published chlamydia-specific CD8 T-cell clones are MHC class II restricted. CONCLUSIONS: The MHC class II-restricted CD8 T cells may play an important role in protection from intracellular pathogens that limit class I antigen presentation or diminish CD4 T-cell numbers or impair their function.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Infecções por Chlamydia/imunologia , Chlamydia muridarum/imunologia , Animais , Infecções por Chlamydia/microbiologia , Células Clonais/virologia , Feminino , Antígenos de Histocompatibilidade Classe I/imunologia , Humanos , Camundongos , Camundongos Endogâmicos C57BL
11.
J Contam Hydrol ; 229: 103581, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31810750

RESUMO

Characterizing the mobility of uranium and vanadium in groundwater with a hydraulic connection to surface water is important to inform the best management practices of former mill tailing sites. In this study, the recharge of river water to the unsaturated and saturated zones of a uranium-contaminated alluvial aquifer was simulated in a series of forced-gradient single- and multi-well injection-extraction tests. The injection fluid (river water) was traced with natural and artificial tracers that included halides, fluorobenzoates, lithium, and naphthalene sulfonate to characterize the potential mass transport mechanisms of uranium and vanadium. The extraction fluid (river water/groundwater mixture) was analyzed for the tracers, uranium, and vanadium. The results from the tracers indicated that matrix diffusion was likely negligible over the spatiotemporal scales of the tests as evident by nearly identical breakthrough curves of the halides and fluorobenzoates. In contrast, the breakthrough curves of lithium and naphthalene sulfonate indicated that sorption by cation exchange and sorption to organic matter, respectively, were potential mass transport mechanisms of uranium and vanadium. Uranium was mobilized in the saturated zone containing gypsum (gypsum-rich zone), the vadose zone (vadose-rich zone), and the saturated zone containing organic carbon (organic-rich zone) whereas vanadium was mobilized only in the saturated gypsum-rich zone. The mechanisms responsible for the mobilization of uranium and vanadium were likely dissolution of uranium- and vanadium-bearing minerals and/or desorption from the gypsum-rich zone, flushing of uranium from the vadose-rich zone, and desorption of uranium from the organic-rich zone due to the natural contrast in the geochemistry between the river water and groundwater. The experimental design of this study was unique in that it employed the use of multiple natural and artificial tracers coupled with a direct injection of native river water to groundwater. These results demonstrated that natural recharge and flooding events at former mill tailing sites can mobilize uranium, and possibly vanadium, and contribute to persistent levels of groundwater contamination.


Assuntos
Água Subterrânea , Urânio/análise , Poluentes Radioativos da Água/análise , Projetos de Pesquisa , Vanádio , Água
12.
J Infect Dis ; 221(5): 841-850, 2020 02 18.
Artigo em Inglês | MEDLINE | ID: mdl-31599954

RESUMO

BACKGROUND: Chlamydia trachomatis and Chlamydia muridarum are intracellular bacterial pathogens of mucosal epithelial cells. CD4 T cells and major histocompatibility complex (MHC) class II molecules are essential for protective immunity against them. Antigens presented by dendritic cells (DCs) expand naive pathogen-specific T cells (inductive phase), whereas antigens presented by epithelial cells identify infected epithelial cells as targets during the effector phase. We previously showed that DCs infected by C trachomatis or C muridarum present epitopes from a limited spectrum of chlamydial proteins recognized by Chlamydia-specific CD4 T cells from immune mice. METHODS: We hypothesized that Chlamydia-infected DCs and epithelial cells present overlapping sets of Chlamydia-MHC class II epitopes to link inductive and effector phases to generate protective immunity. We tested that hypothesis by infecting an oviductal epithelial cell line with C muridarum, followed by immunoaffinity isolation and sequencing of MHC class I- and II-bound peptides. RESULTS: We identified 26 class I-bound and 4 class II-bound Chlamydia-derived peptides from infected epithelial cells. We were surprised to find that none of the epithelial cell class I- and class II-bound chlamydial peptides overlapped with peptides presented by DCs. CONCLUSIONS: We suggest the discordance between the DC and epithelial cell immunoproteomes has implications for delayed clearance of Chlamydia and design of a Chlamydia vaccine.


Assuntos
Infecções por Chlamydia/imunologia , Chlamydia muridarum/imunologia , Chlamydia trachomatis/imunologia , Células Dendríticas/imunologia , Células Epiteliais/imunologia , Antígenos de Histocompatibilidade Classe II/imunologia , Interações Hospedeiro-Patógeno/imunologia , Animais , Antígenos de Bactérias/imunologia , Vacinas Bacterianas/imunologia , Linfócitos T CD4-Positivos/imunologia , Linhagem Celular , Infecções por Chlamydia/microbiologia , Epitopos de Linfócito T/imunologia , Feminino , Células HeLa , Antígenos de Histocompatibilidade Classe I/imunologia , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Peptídeos/imunologia
13.
J Contam Hydrol ; 213: 28-39, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29691066

RESUMO

This research assesses the ability of a GC SCM to simulate uranium transport under variable geochemical conditions typically encountered at uranium in-situ recovery (ISR) sites. Sediment was taken from a monitoring well at the SRH site at depths 192 and 193 m below ground and characterized by XRD, XRF, TOC, and BET. Duplicate column studies on the different sediment depths, were flushed with synthesized restoration waters at two different alkalinities (160 mg/l CaCO3 and 360 mg/l CaCO3) to study the effect of alkalinity on uranium mobility. Uranium breakthrough occurred 25% - 30% earlier in columns with 360 mg/l CaCO3 over columns fed with 160 mg/l CaCO3 influent water. A parameter estimation program (PEST) was coupled to PHREEQC to derive site densities from experimental data. Significant parameter fittings were produced for all models, demonstrating that the GC SCM approach can model the impact of carbonate on uranium in flow systems. Derived site densities for the two sediment depths were between 141 and 178 µmol-sites/kg-soil, demonstrating similar sorption capacities despite heterogeneity in sediment mineralogy. Model sensitivity to alkalinity and pH was shown to be moderate compared to fitted site densities, when calcite saturation was allowed to equilibrate. Calcite kinetics emerged as a potential source of error when fitting parameters in flow conditions. Fitted results were compared to data from previous batch and column studies completed on sediments from the Smith-Ranch Highland (SRH) site, to assess variability in derived parameters. Parameters from batch experiments were lower by a factor of 1.1 to 3.4 compared to column studies completed on the same sediments. The difference was attributed to errors in solid-solution ratios and the impact of calcite dissolution in batch experiments. Column studies conducted at two different laboratories showed almost an order of magnitude difference in fitted site densities suggesting that experimental methodology may play a bigger role in column sorption behavior than actual sediment heterogeneity. Our results demonstrate the necessity for ISR sites to remove residual pCO2 and equilibrate restoration water with background geochemistry to reduce uranium mobility. In addition, the observed variability between fitted parameters on the same sediments highlights the need to provide standardized guidelines and methodology for regulators and industry when the GC SCM approach is used for ISR risk assessments.


Assuntos
Sedimentos Geológicos/química , Urânio/análise , Poluentes Químicos da Água/análise , Poluentes Radioativos da Água/análise , Adsorção , Carbonato de Cálcio/química , Concentração de Íons de Hidrogênio , Hidrologia/métodos , Cinética , Modelos Teóricos , Incerteza , Urânio/química , Poluentes Químicos da Água/química , Poluentes Radioativos da Água/química , Wyoming , Difração de Raios X
14.
Infect Immun ; 86(2)2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29158429

RESUMO

Surveillance and defense of the enormous mucosal interface with the nonsterile world are critical to protecting the host from a wide range of pathogens. Chlamydia trachomatis is an intracellular bacterial pathogen that replicates almost exclusively in the epithelium of the reproductive tract. The fallopian tubes and vagina are poorly suited to surveillance and defense, with limited immune infrastructure positioned near the epithelium. However, a dynamic process during clearing primary infections leaves behind new lymphoid clusters immediately beneath the epithelium. These memory lymphocyte clusters (MLCs) harboring tissue-resident memory (Trm) T cells are presumed to play an important role in protection from subsequent infections. Histologically, human Chlamydia MLCs have prominent B cell populations. We investigated the status of genital tract B cells during C. muridarum infections and the nature of T cells recovered from immune mice using immune B cells as antigen-presenting cells (APCs). These studies revealed a genital tract plasma B cell population and a novel genital tract CD4 T cell subset producing both gamma interferon (IFN-γ) and interleukin-13 (IL-13). A panel of CD4 T cell clones and microarray analysis showed that the molecular fingerprint of CD4γ13 T cells includes a Trm-like transcriptome. Adoptive transfer of a Chlamydia-specific CD4γ13 T cell clone completely prevented oviduct immunopathology without accelerating bacterial clearance. Existence of a CD4γ13 T cell subset provides a plausible explanation for the observation that human peripheral blood mononuclear cell (PBMC) Chlamydia-specific IFN-γ and IL-13 responses predict resistance to reinfection.


Assuntos
Apresentação de Antígeno , Linfócitos B/imunologia , Infecções por Chlamydia/imunologia , Chlamydia muridarum/imunologia , Genitália Feminina/imunologia , Memória Imunológica , Subpopulações de Linfócitos T/imunologia , Animais , Infecções por Chlamydia/microbiologia , Modelos Animais de Doenças , Feminino , Perfilação da Expressão Gênica , Camundongos Endogâmicos C57BL , Infecções do Sistema Genital/imunologia , Infecções do Sistema Genital/microbiologia
16.
Open Forum Infect Dis ; 3(3): ofw160, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27704015

RESUMO

Background. Pediatric Kawasaki disease (KD) and human immunodeficiency virus (HIV)+ adult Kawasaki-like syndrome (KLS) are dramatic vasculitides with similar physical findings. Both syndromes include unusual arterial histopathology with immunoglobulin (Ig)A+ plasma cells, and both impressively respond to pooled Ig therapy. Their distinctive presentations, histopathology, and therapeutic response suggest a common etiology. Because blood is in immediate contact with inflamed arteries, we investigated whether KD and KLS share an inflammatory signature in serum. Methods. A custom multiplex enzyme-linked immunosorbent assay (ELISA) defined the serum cytokine milieu in 2 adults with KLS during acute and convalescent phases, with asymptomatic HIV+ subjects not taking antiretroviral therapy serving as controls. We then prospectively collected serum and plasma samples from children hospitalized with KD, unrelated febrile illnesses, and noninfectious conditions, analyzing them with a custom multiplex ELISA based on the KLS data. Results. Patients with KLS and KD subjects shared an inflammatory signature including acute-phase reactants reflecting tumor necrosis factor (TNF)-α biologic activity (soluble TNF receptor I/II) and endothelial/smooth muscle chemokines Ccl1 (Th2), Ccl2 (vascular inflammation), and Cxcl11 (plasma cell recruitment). Ccl1 was specifically elevated in KD versus febrile controls, suggesting a unique relationship between Ccl1 and KD/KLS pathogenesis. Conclusions. This study defines a KD/KLS inflammatory signature mirroring a dysfunctional response likely to a common etiologic agent. The KD/KLS inflammatory signature based on elevated acute-phase reactants and specific endothelial/smooth muscle chemokines was able to identify KD subjects versus febrile controls, and it may serve as a practicable diagnostic test for KD.

17.
Anesth Analg ; 123(3): 698-702, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27537759

RESUMO

BACKGROUND: Vasoactive agents administered to counter maternal hypotension at cesarean delivery may theoretically intensify the hypoxemic fetoplacental vasoconstrictor response and, hence, negatively impact transplacental oxygen delivery to the fetus. Yet, this aspect of their pharmacodynamic profiles is seldom mentioned, let alone investigated. We hypothesized that vasopressin, a potent systemic vasoconstrictor, and oxytocin, a uterotonic agent administered routinely at cesarean delivery, which, in contrast to vasopressin, possesses significant systemic vasodilator properties, would not influence distal stem villous arteriolar resistance. METHODS: The dual-perfused, single, isolated cotyledon, human placental perfusion model was used to examine the resistance response of the fetoplacental circulation to oxytocin and vasopressin in placentae harvested from healthy women. Twelve of a total of 17 individual experiments were conducted successfully during which either oxytocin (n = 6) or vasopressin (n = 6) was introduced into the fetal reservoir in concentration increments of 10 M. Fetoplacental distal stem villous arteriolar perfusion pressure (FAP) was measured continuously. The fetal circuit concentration of either oxytocin or vasopressin was raised in a stepwise fashion from 10 to 10 M or 10 to 10 M, respectively. Both reservoirs were then purged of drug, after which 1-mL 1.0 mM 5-hydroxytryptamine (2.5 µM), an agent well known to manifestly increase fetoplacental distal stem villous arteriolar resistance, was introduced into the fetal circuit. A significant increase in FAP from baseline in response to exposure to 5-hydroxytryptamine confirmed that the fetoplacental vasoconstrictor response remained reactive. The primary outcome of this study was changes in FAP after incremental dosing of vasopressin and oxytocin. RESULTS: No changes in FAP were observed with either oxytocin or vasopressin regardless of the drug concentration tested. For each drug and concentration, a mean pressure change greater than ±10 mm Hg was excluded with 95% confidence. In contrast, 5-hydroxytryptamine significantly increased perfusion pressure in all 12 successful experiments. CONCLUSIONS: Oxytocin and vasopressin do not influence human fetoplacental distal stem villous arteriolar resistance. The neutral impact of vasopressin noted here is thus analogous to the reported negligible influence of the drug on human pulmonary arteriolar resistance. Neither drug seems likely to adversely influence the compensatory hypoxemic fetoplacental vasoconstrictor response.


Assuntos
Ocitocina/farmacologia , Perfusão/métodos , Placenta/efeitos dos fármacos , Circulação Placentária/efeitos dos fármacos , Resistência Vascular/efeitos dos fármacos , Vasopressinas/farmacologia , Relação Dose-Resposta a Droga , Feminino , Humanos , Técnicas de Cultura de Órgãos , Perfusão/instrumentação , Placenta/fisiologia , Circulação Placentária/fisiologia , Gravidez , Resistência Vascular/fisiologia
18.
Infect Immun ; 84(4): 868-873, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26787715

RESUMO

For almost 2 decades, results from Chlamydia pathogenesis investigations have been conceptualized using a cytokine polarization narrative. Recent viral immunity studies identifying protective tissue-resident memory T cells (Trm) suggest an alternative paradigm based on localized immune networks. As Chlamydia vaccines enter the preclinical pipeline and, in the case of an attenuated trachoma vaccine, are given to human subjects, it may be useful to ask whether cytokine polarization is the appropriate framework for understanding and evaluating vaccine efficacy. In this review, we revisit C. trachomatis pathogenesis data from mice and humans using a Trm narrative and note a comfortable concordance with the Chlamydia pathogenesis literature.


Assuntos
Vacinas Bacterianas/normas , Infecções por Chlamydia/prevenção & controle , Chlamydia/imunologia , Linfócitos T/fisiologia , Animais , Infecções por Chlamydia/imunologia , Humanos
19.
Pathog Dis ; 73(9): ftv100, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26519447

RESUMO

Chlamydia trachomatis urogenital serovars are intracellular bacteria that parasitize human reproductive tract epithelium. As the principal cell type supporting bacterial replication, epithelial cells are central to Chlamydia immunobiology initially as sentries and innate defenders, and subsequently as collaborators in adaptive immunity-mediated bacterial clearance. In asymptomatic individuals who do not seek medical care a decisive struggle between C. trachomatis and host defenses occurs at the epithelial interface. For this study, we modeled the immunobiology of epithelial cells and macrophages lining healthy genital mucosa and inflamed/infected mucosa during the transition from innate to adaptive immunity. Upper reproductive tract epithelial cell line responses were compared to bone marrow-derived macrophages utilizing gene expression microarray technology. Those comparisons showed minor differences in the intrinsic innate defenses of macrophages and epithelial cells. Major lineage-specific differences in immunobiology relate to epithelial collaboration with adaptive immunity including an epithelial requirement for inflammatory cytokines to express MHC class II molecules, and a paucity and imbalance between costimulatory and coinhibitory ligands on epithelial cells that potentially limits sterilizing immunity (replication termination) to Chlamydia-specific T cells activated with limited or unconventional second signals.


Assuntos
Infecções por Chlamydia/microbiologia , Chlamydia muridarum/crescimento & desenvolvimento , Células Epiteliais/fisiologia , Perfilação da Expressão Gênica , Interações Hospedeiro-Patógeno , Macrófagos/fisiologia , Infecções do Sistema Genital/microbiologia , Imunidade Adaptativa , Animais , Linhagem Celular , Infecções por Chlamydia/imunologia , Infecções por Chlamydia/patologia , Células Epiteliais/microbiologia , Feminino , Imunidade Inata , Macrófagos/microbiologia , Camundongos Endogâmicos C57BL , Análise em Microsséries , Modelos Biológicos , Mucosa/citologia , Mucosa/microbiologia , Infecções do Sistema Genital/imunologia , Infecções do Sistema Genital/patologia
20.
PLoS One ; 9(2): e86964, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24516541

RESUMO

UNLABELLED: The pathogenesis of accelerated liver damage in subjects coinfected with hepatitis C virus (HCV) and human immunodeficiency virus type 1 (HIV-1) remains largely unknown. Recent studies suggest that ongoing chronic liver inflammation is responsible for the liver injury in HCV-infected patients. We aimed to determine whether HIV-1 coinfection altered intrahepatic inflammatory profiles in HCV infection, thereby hastening liver damage. We used a real-time RT-PCR-based array to comparatively analyze intrahepatic inflammation gene profiles in liver biopsy specimens from HCV-infected (n = 16), HCV/HIV-1-coinfected (n = 8) and uninfected (n = 8) individuals. We then used human hepatocytes to study the molecular mechanisms underlying alternations of the inflammatory profiles. Compared with uninfected individuals, HCV infection and HCV/HIV-1 coinfection markedly altered expression of 59.5% and 50.0% of 84 inflammation-related genes tested, respectively. Among these genes affected, HCV infection up-regulated the expression of 24 genes and down-regulated the expression of 26 genes, whereas HCV/HIV-1 coinfection up-regulated the expression of 21 genes and down-regulated the expression of 21 genes. Compared with HCV infection, HCV/HIV-1 coinfection did not dramatically affect intrahepatic gene expression profiles of cytokines and their receptors, but profoundly altered expression of several chemokine genes including up-regulation of the CXCR3-associated chemokines. Human hepatocytes produced these chemokines in response to virus-related microbial translocation, viral protein stimulation, and antiviral immune responses. CONCLUSIONS: HIV-1 coinfection profoundly alters intrahepatic chemokine but not cytokine profiles in HCV-infected subjects. The altered chemokines may orchestrate the tissue-specific and cell-selective trafficking of immune cells and autoimmunity to accelerate liver disease in HCV/HIV-1 coinfection.


Assuntos
Quimiocinas/metabolismo , Coinfecção/virologia , Infecções por HIV/complicações , Infecções por HIV/virologia , Hepatite C/complicações , Mediadores da Inflamação/metabolismo , Fígado/patologia , Adolescente , Adulto , Idoso , Quimiocinas/genética , Estudos de Coortes , Coinfecção/genética , Demografia , Feminino , Regulação da Expressão Gênica , Infecções por HIV/genética , Hepatite C/genética , Hepatite C/virologia , Hepatócitos/metabolismo , Hepatócitos/patologia , Hepatócitos/virologia , Humanos , Lipopolissacarídeos/farmacologia , Fígado/metabolismo , Fígado/virologia , Masculino , Pessoa de Meia-Idade , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores CXCR3/metabolismo , Adulto Jovem
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