RESUMO
Electronic fetal monitoring, particularly in the form of cardiotocography, forms the centerpiece of labor management. Initially successfully designed for stillbirth prevention, there was hope to also include prediction and prevention of fetal acidosis and its sequelae. With the routine use of electronic fetal monitoring, the cesarean delivery rate increased from <5% in the 1970s to >30% at present. Most at-risk cases produced healthy babies, resulting in part from considerable confusion as to the differences between diagnostic and screening tests. Electronic fetal monitoring is clearly a screening test. Multiple attempts have aimed at enhancing its ability to accurately distinguish babies at risk of in utero injury from those who are not and to do this in a timely manner so that appropriate intervention can be performed. Even key electronic fetal monitoring opinion leaders admit that this goal has yet to be achieved. Our group has developed a modified approach called the "Fetal Reserve Index" that contextualizes the findings of electronic fetal monitoring by formally including the presence of maternal, fetal, and obstetrical risk factors and increased uterine contraction frequencies and breaking up the tracing into 4 quantifiable components (heart rate, variability, decelerations, and accelerations). The result is a quantitative 8-point metric, with each variable being weighted equally in version 1.0. In multiple previously published refereed papers, we have shown that in head-to-head studies comparing the fetal reserve index with the American College of Obstetricians and Gynecologists' fetal heart rate categories, the fetal reserve index more accurately identifies babies born with cerebral palsy and could also reduce the rates of emergency cesarean delivery and vaginal operative deliveries. We found that the fetal reserve index scores and fetal pH and base excess actually begin to fall earlier in the first stage of labor than was commonly appreciated, and the fetal reserve index provides a good surrogate for pH and base excess values. Finally, the last fetal reserve index score before delivery combined with early analysis of neonatal heart rate and acid/base balance shows that the period of risk for neonatal neurologic impairment can continue for the first 30 minutes of life and requires much closer neonatal observation than is currently being done.
Assuntos
Cardiotocografia , Trabalho de Parto , Recém-Nascido , Feminino , Gravidez , Humanos , Cardiotocografia/métodos , Parto Obstétrico/métodos , Cesárea , Cuidado Pré-Natal , Frequência Cardíaca Fetal/fisiologia , Monitorização FetalRESUMO
Polypropylene was modified to contain chitosan and evaluate its ability to generate Lactobacillus casei biofilms and their lactic acid production. Biofilm formation was carried out in either rich or minimal media. The chitosan-modified polypropylene harbored ~ 37% more cells than the control polypropylene. The biofilms from the chitosan-modified polypropylene grown in rich medium produced ~ 2 times more lactic acid after 72 h of incubation than the control suspended cells. There was no significant difference in the production of lactic acid after 72 h by L. casei biofilms on the chitosan-modified polypropylene grown in minimal media as compared with cells in suspension after 48 h and 72 h of incubation. Infrared spectroscopy confirmed higher deposition of nutrients and biomass on the chitosan-modified polypropylene as compared to the chitosan-free polypropylene. Electron and atomic force microscopy confirmed thicker biofilms when rich media were used to grow them as compared to minimal medium.
Assuntos
Ácido Láctico/metabolismo , Lactobacillus/metabolismo , BiofilmesRESUMO
Strategies to reduce crop losses due to drought are needed as climate variability affects agricultural productivity. Wheat (Triticum aestivum var. Juniper) growth in a nutrient-sufficient, solid growth matrix containing varied doses of CuO, ZnO, and SiO2 nanoparticles (NPs) was used to evaluate NP mitigation of drought stress. NP amendments were at fertilizer levels, with maxima of 30 Cu, 20 Zn, and 200 Si (mg metal/kg matrix). Seeds of this drought-tolerant cultivar were inoculated with Pseudomonas chlororaphis O6 (PcO6) to provide a protective root microbiome. An 8 day drought imposed on 14 day-old wheat seedlings decreased shoot and root mass, shoot water content, and the quantum yield of photosystem II when compared to watered plants. PcO6 root colonization was not impaired by drought or NPs. A dose-dependent increase in the Cu, Zn, and Si from the NPs was observed from analysis of the rhizosphere solution, and this process was not affected by drought. Consequently, fertilizer concentrations of the NPs did not further improve drought tolerance in wheat seedlings under the growth conditions of adequate mineral nutrition and the presence of a beneficial microbiome. These findings suggest that potential NP benefits in promoting plant drought tolerance occur only under certain environmental conditions.
Assuntos
Nanopartículas , Óxido de Zinco , Secas , Nutrientes , Raízes de Plantas , Plântula , Dióxido de Silício , TriticumRESUMO
Electronic fetal monitoring (EFM) is a poor predictor of outcomes attributable to delivery problems. Contextualizing EFM by adding maternal, obstetrical, and fetal risk-related information to create an index called the Fetal Reserve Index (FRI) improves the predictive capacity and facilitates the timing of interventions. Here, we test critical assumptions of FRI as a clinical tool. Our conceptualization implies that the earlier one reaches the red zone (FRI ≤25) and the longer one spends in the red zone, the greater the likelihood of emergency operative deliveries (EOD). METHODS: We analyzed 1,402 patients using logistic regression predicting the probability of EOD and employed qualitative methodology techniques to refine predictive capabilities. RESULTS: Reaching the red zone early and staying there > 1 h increases the probability of EOD. When these risk factors are paired with intrauterine resuscitation (IR) in Stage 1, the reduction of EOD is substantial. CONCLUSION: FRI is a capable predictor of EOD because it accurately identifies the level of malleable risk. FRI analysis increases the risk of using IR in Stage 1. Matching risk and resources dramatically reduces the chances of EOD. Earlier IR improves the outcomes if the calculated risk is high.
Assuntos
Cardiotocografia , Paralisia Cerebral/prevenção & controle , Cesárea , Parto Obstétrico/métodos , Adulto , Feminino , Sofrimento Fetal , Frequência Cardíaca Fetal , Humanos , Recém-Nascido , Gravidez , Fatores de RiscoRESUMO
Organosilanes (e.g., R'-SiOR3) provide hydrophobic functionality in thin-film coatings, porous gels, and particles. Compared with tetraalkoxysilanes (SiOR4), organosilanes exhibit distinct reaction kinetics and assembly mechanisms arising from steric and electronic properties of the R' group on the silicon atom. Here, the hydrolysis and condensation pathways of n-propyltrimethoxy silane (nPM) and a tri-fluorinated analog of nPM, 3,3,3-trifluoropropyl trimethoxy silane (3F), were investigated under aqueous conditions at pH 1.7, 2.0, 3.0, and 4.0. Prior to hydrolysis, 3F and nPM are insoluble in water and form a lens at the bottom (3F) or top (nPM) of the solutions. This phase separation was employed to follow reaction kinetics using a Turbiscan instrument to monitor hydrolysis through solubilization of the neat silane lens while simultaneously tracking condensation-induced turbidity throughout the bulk solution. Dynamic light scattering confirmed the silane condensation and particle aggregation processes reported by the turbidity scanning. Employing macroscopic phase separation of the starting reactants from the solvent further allows for control over the reaction kinetics, as the interfacial area can be readily controlled by reaction vessel geometry, namely by controlling the surface area to volume. In-situ turbidity scanning and dynamic light scattering revealed distinct reaction kinetics for nPM and 3F, attributable to the electron withdrawing and donating nature of the fluoro- and organo-side chains of 3F and nPM, respectively.
Assuntos
Difusão Dinâmica da Luz , Géis/química , Transição de Fase , Silanos/química , Soluções/química , Fenômenos Químicos , Difusão Dinâmica da Luz/métodos , Concentração de Íons de Hidrogênio , Hidrólise , Interações Hidrofóbicas e Hidrofílicas , Cinética , Nanopartículas/químicaRESUMO
This study introduces a simple and environmentally friendly method to synthesize silica-protein nanocomposite materials using microwave energy to solubilize hydrophobic protein in an aqueous solution of pre-hydrolyzed organo- or fluoro-silane. Sol-gel functionality can be enhanced through biomacromolecule incorporation to tune mechanical properties, surface energy, and biocompatibility. Here, synthetic spider silk protein and organo- and fluoro-silane precursors were dissolved and mixed in weakly acidic aqueous solution using microwave technology. Scanning electron microscopy (SEM) and Atomic force microscopy (AFM) images revealed the formation of spherical nanoparticles with sizes ranging from 100 to 500 nm depending, in part, on silane fluoro- or organo-side chain chemistry. The silane-protein interaction in the nanocomposite was assessed through infrared spectroscopy. Deconvoluted ATR-FTIR (Attenuated total reflectance Fourier-transform infrared spectroscopy) spectra revealed silane chemistry-specific conformational changes in the protein-silane nanocomposites. Relative to microwave-solubilized spider silk protein, the ß structure content increased by 14% in the spider silk-organo-silica nanocomposites, but decreased by a net 20% in the spider silk-fluoro-silica nanocomposites. Methods of tuning the secondary structures, and in particular ß-sheets that are the cross-linking moieties in spider silks and other self-assembling fibrillar proteins, may provide a unique means to promote protein interactions, favor subsequent epitaxial growth process, and enhance the properties of the protein-silane nanocomposites.
Assuntos
Micro-Ondas , Nanocompostos/química , Dióxido de Silício/química , Géis de Silicone/química , Seda/química , Aranhas/química , Animais , Microscopia de Força Atômica , Nanocompostos/ultraestrutura , Géis de Silicone/síntese química , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
Cost-effective "green" methods of producing Ag nanoparticles (NPs) are being examined because of the potential of these NPs as antimicrobials. Ag NPs were generated from Ag ions using extracellular metabolites from a soil-borne Pythium species. The NPs were variable in size, but had one dimension less than 50 nm and were biocoated; aggregation and coating changed with acetone precipitation. They had dose-dependent lethal effects on a soil pseudomonad, Pseudomonas chlororaphis O6, and were about 30-fold more effective than Ag(+) ions. A role of reactive oxygen species in cell death was demonstrated by use of fluorescent dyes responsive to superoxide anion and peroxide accumulation. Also mutants of the pseudomonad, defective in enzymes that protect against oxidative stress, were more sensitive than the wild type strain; mutant sensitivity differed between exposure to Ag NPs and Ag(+) ions demonstrating a nano-effect. Imaging of bacterial cells treated with the biocoated Ag NPs revealed no cell lysis, but there were changes in surface properties and cell height. These findings support that biocoating the NPs results in limited Ag release and yet they retained potent antimicrobial activity.
Assuntos
Anti-Infecciosos/farmacologia , Nanopartículas Metálicas/química , Prata/farmacologia , Anti-Infecciosos/química , Reatores Biológicos , Peróxido de Hidrogênio/farmacologia , Testes de Sensibilidade Microbiana , Tamanho da Partícula , Pseudomonas chlororaphis/efeitos dos fármacos , Pseudomonas chlororaphis/ultraestrutura , Pythium/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Prata/químicaRESUMO
OBJECTIVES: The explosion in genetic technologies, including array comparative genomic hybridization (aCGH), has increased the complexity of genetic counseling. We now offer chorionic villus sampling (CVS) and aCGH to all first-trimester patients, as this allows the prenatal diagnosis of an additional 1% of anomalies not otherwise detectable and can detect genetic copy number variants at a much higher resolution than conventional cytogenetics. Here, we explored some of the determinants of how patients are deciding to use or not use this new technology and evaluate risk-benefit analyses for that decision. METHODS: This is a retrospective case-control study of singleton and multiples pregnancies at our center. Those having aCGH testing along with CVS were defined as 'testers' and those who declined aCGH but had the CVS were 'nontesters'. RESULTS: Demographic data of 181 educated women who chose CVS were compared. Among those carrying singletons (n = 144), older women, defined as over 35 years of age (or 'advanced maternal age'; AMA), were more likely to choose the aCGH than younger women. Further, women who had a prior history of genetic testing and who wanted to know the gender of the fetus were more likely to choose the aCGH test. In women carrying multiples (n = 37), AMA ceases to be a predictor of choice. Having had prior genetic counseling remains a strong predictor for choosing aCGH, as does wanting to know the gender of the fetus. Neither prior abortions nor having prior children were significant for women carrying singletons or multiples. CONCLUSION: Offering pregnant couples an individualized choice regarding aCGH seems an appropriate approach. There are discrete patterns associated with the choice of taking the aCGH that varied depending on whether the patient was carrying a singleton or multiples.
Assuntos
Amostra da Vilosidade Coriônica , Tomada de Decisão Clínica , Testes Genéticos , Diagnóstico Pré-Natal/tendências , Adulto , Amniocentese , Hibridização Genômica Comparativa/estatística & dados numéricos , Feminino , Aconselhamento Genético , Humanos , Idade Materna , Gravidez , Primeiro Trimestre da Gravidez , Diagnóstico Pré-Natal/psicologia , Estudos RetrospectivosRESUMO
We explored health professionals' views of implementing a systematic voiding program (SVP) in a multi-site qualitative process evaluation in stroke services recruited to the intervention arms of a cluster randomized controlled feasibility trial during 2011-2013. We conducted semi-structured group or individual interviews with 38 purposively selected nursing, managerial, and care staff involved in delivering the SVP. Content analysis of transcripts used normalization process theory (NPT) as a pre-specified organization-level exploratory framework. Barriers to implementing the SVP included perceived lack of suitability for some patient groups, patient fear of extending hospital stay, and difficulties with SVP enactment, scheduling, timing, recording, and monitoring. Enablers included the guidance provided by the SVP, patient and relative involvement, extra staff, improved nursing skill and confidence, and experience of success. Three potential mechanisms of consistency, visibility, and individualization linked the SVP process with improvements in outcome, and should be emphasized in SVP implementation.
Assuntos
Atitude do Pessoal de Saúde , Acidente Vascular Cerebral/complicações , Incontinência Urinária/terapia , Humanos , Pesquisa Qualitativa , Ensaios Clínicos Controlados Aleatórios como AssuntoRESUMO
Zn is an essential element for plants yet some soils are Zn-deficient and/or have low Zn-bioavailability. This paper addresses the feasibility of using ZnO nanoparticles (NPs) as soil amendments to improve Zn levels in the plant. The effects of soil properties on phytotoxicity and Zn bioavailability from the NPs were studied by using an acidic and a calcareous alkaline soil. In the acid soil, the ZnO NPs caused dose-dependent phytotoxicity, observed as inhibition of elongation of roots of wheat, Triticum aestivum. Phytotoxicity was mitigated in the calcareous alkaline soil although uptake of Zn from the ZnO NPs occurred doubling the Zn level compared to control plants. This increase occurred with a low level of Zn in the soil solution as expected from the interactions of Zn with the soil components at the alkaline pH. Soluble Zn in the acid soil was 200-fold higher and shoot levels were tenfold higher than from the alkaline soil correlating with phytotoxicity. Mitigation of toxicity was not observed in plants grown in sand amended with a commercial preparation of humic acid: growth, shoot uptake and solubility of Zn from the NPs was not altered by the humic acid. Thus, variation in humic acid between soils may not be a major factor influencing plant responses to the NPs. These findings illustrate that formulations of ZnO NPs to be used as a soil amendment would need to be tuned to soil properties to avoid phytotoxicity yet provide increased Zn accumulations in the plant.
Assuntos
Nanopartículas/química , Nanopartículas/toxicidade , Triticum/efeitos dos fármacos , Óxido de Zinco/química , Óxido de Zinco/toxicidade , Raízes de Plantas/efeitos dos fármacos , Brotos de Planta/efeitos dos fármacos , SoloRESUMO
The expansion of nanotechnology raises concerns about the consequences of nanomaterials in plants. Here, the effects of nanoparticles (NPs; 100-500 mg/kg) on processes related to micronutrient accumulation were evaluated in bean (Phaseolus vulgaris) exposed to CuO NPs, a mixture of CuO and ZnO (CuO:ZnO) NPs, and in CuO NP-exposed plants colonized by a root bacterium, Pseudomonas chlororaphis O6 (PcO6) in a sand matrix for 7 days. Depending on exposure levels, the inhibition of growth by CuO NPs was more apparent in roots (10-66 %) than shoots (9-25 %). In contrast, CuO:ZnO NPs or root colonization with PcO6 partially mitigated growth inhibition. At 500 mg/kg exposure, CuO NPs increased soluble Cu in the growth matrix by 23-fold, relative to the control, while CuO:ZnO NPs increased soluble Cu (26-fold), Zn (127-fold) and Ca (4.5-fold), but reduced levels of Fe (0.8-fold) and Mn (0.75-fold). Shoot accumulations of Cu (3.8-fold) and Na (1-fold) increased, while those of Fe (0.4-fold), Mn (0.2-fold), Zn (0.5-fold) and Ca (0.5-fold) were reduced with CuO NP (500 mg/kg) exposure. CuO:ZnO NPs also increased shoot Cu, Zn and Na levels, while decreasing that of Fe, Mn, Ca and Mg. Root colonization reduced shoot uptake of Cu and Na, 15 and 24 %, respectively. CuO NPs inhibited ferric reductase (up to 49 %) but stimulated cupric (up to 273 %) reductase activity; while CuO:ZnO NPs or root colonization by PcO6 altered levels of ferric, but not copper reductase activity, relative to CuO NPs. Cu ions at the level released from the NPs did not duplicate these effects. Our findings demonstrate that in addition to the apparent phytotoxic effects of NPs, NP exposure may also have subtle impacts on secondary processes such as metal nutrition.
Assuntos
Cobre/toxicidade , Nanopartículas Metálicas/toxicidade , Phaseolus/efeitos dos fármacos , Microbiologia do Solo , Óxido de Zinco/toxicidade , Metais/metabolismo , Phaseolus/metabolismo , Phaseolus/microbiologia , Pseudomonas/crescimento & desenvolvimentoRESUMO
CuO and ZnO nanoparticles (NPs) have antimicrobial effects that could lead to formulations as pesticides for agriculture or medicine. The responses of two soil-borne plant pathogenic Pythium isolates to the NPs were studied to determine the potential of these metal oxide NPs as pesticides. Growth of the P. ultimum isolate was more sensitive to CuO NPs than the P. aphanidermatum isolate. Growth in liquid medium with CuO NPs eliminated culturability whereas exposure to ZnO NPs resulted in stasis with growth resuming on transfer to medium lacking NPs. The citrate in the medium used for the growth assays was involved in enhanced release of the toxic metals from the NPs. Both CuO and ZnO NPs affected processes involved in Fe uptake. The NPs reduced levels of Fe-chelating siderophore-like metabolites produced by Pythium hyphae. CuO NPs inhibited, but ZnO NPs increased, ferric reductase activity detected at the mycelial surface. These findings illustrate that the toxicity of the metal oxide NPs towards Pythium was influenced by the medium, especially by the presence of a metal chelator. Environmental factors are likely to alter the pesticide potential of the metal oxide NPs when formulated for agricultural use in soils.
Assuntos
Cobre/farmacologia , Fungicidas Industriais/farmacologia , Nanopartículas Metálicas/química , Pythium/efeitos dos fármacos , Óxido de Zinco/farmacologia , FMN Redutase/metabolismo , Pythium/metabolismo , Sideróforos/metabolismoRESUMO
Fetal reduction (FR) began in the 1980s to salvage the pregnancies of couples needing fertility therapy who were finally successful but with too many fetuses. Since then, it has gone from a rarity performed in only the highest risk situations to an integral fail-safe of infertility practice. Our understanding of the problems of multiple and premature births has increased - even twins carry 4-5 times more risk than singletons. Evaluation of fetuses before FR has permitted more intelligent choices and improved resultant outcomes. We now perform chorionic villus sampling in approximately 85% of cases, obtain fluorescent in situ hybridization (FISH) results overnight, and then perform FR the next day. Decisions about which to reduce prioritize anomalies, but now can include fetal gender in the decision process, as couples are now just as likely to want girls as boys. In Mendelian cases, sophisticated molecular analyses permit diagnoses before FR, and new uses such as paternity analysis can be performed. Ethical arguments have also evolved; as with many technologies in which the start was for only 'life or death cases', FR has also moved into 'quality of life' issues. FR of twins to a singleton now compromise about 30% of our cases.
Assuntos
Complicações na Gravidez/prevenção & controle , Redução de Gravidez Multifetal/história , Feminino , História do Século XX , História do Século XXI , Humanos , Gravidez , Resultado da Gravidez , Redução de Gravidez Multifetal/ética , Gravidez Múltipla , Transferência de Embrião ÚnicoRESUMO
Cerebral palsy (CP) has been recognized as a group of neurologic disorders with varying etiologies and ontogenies. While a percentage of CP cases arises during labor, the expanded use of electronic fetal monitoring (EFM) to include prevention of CP has resulted in decades of vastly increased interventions that have not significantly reduced the incidence of CP for infants born at term in the USA. Litigation alleging that poor obstetrical practice caused CP in most of these affected children has led to contentious arguments regarding the actual etiologies of this condition and often resulted in substantial monetary awards for plaintiffs. Recent advances in genetic testing using whole exome sequencing have revealed that at least one-third of CP cases in term infants are genetic in origin and therefore not labor-related. Here, we will present and discuss previous attempts to sort out contributing etiologies and ontogenies of CP, and how these newer diagnostic techniques are rapidly improving our ability to better detect and understand such cases. In light of these developments, we present our vision for an overarching spectrum for proper categorization of CP cases into that the following groups: (1) those begun at conception from genetic causes (nonpreventable); (2) those stemming from adverse antenatal/pre-labor events (possibly preventable with heightened antepartum assessment); (3) Those arising from intrapartum events (potentially preventable by earlier interventions); (4) Those occurring shortly after birth (possibly preventable with closer neonatal monitoring); (5) Those that appear later in the postnatal period from non-labor-related causes such as untreated infections or postnatal intracranial hemorrhages.
Assuntos
Paralisia Cerebral , Humanos , Paralisia Cerebral/etiologia , Paralisia Cerebral/diagnóstico , Paralisia Cerebral/epidemiologia , Paralisia Cerebral/prevenção & controle , Paralisia Cerebral/genética , Gravidez , Feminino , Recém-NascidoRESUMO
OBJECTIVE: Determine whether combination therapy with ganciclovir (GCV) and a Quercetin-P188 solution improves hearing outcomes in a murine cytomegalovirus (CMV) model. METHODS: BALB/c mice were infected with murine CMV on postnatal day 3 (p3). Quercetin was solubilized in saline using P188 (QP188). Treatment groups received either GCV, QP188, GCV and QP188, or P188 delivery vehicle BID at 12-hour intervals via intraperitoneal injection. All treatment groups were treated for 14 days starting at p3. Uninfected controls were treated with the combined regimen, saline or P188 delivery vehicle. Auditory thresholds were assessed using distortion product otoacoustic emission (DPOAE) and auditory brainstem response (ABR) testing at 4, 6, and 8 weeks of age. Temporal bones from separate CMV-infected groups were harvested at p10, and viral load was determined by quantitative polymerase chain reaction. RESULTS: CMV-infected mice receiving combination therapy GCV+QP188 demonstrated statistically significant lower ABR (p < 0.001) and DPOAE thresholds (p < 0.001) compared with mice treated with GCV monotherapy, QP188 monotherapy, and P188 delivery vehicle at 4, 6, and 8 weeks of age. GCV+QP188 combination therapy, GCV monotherapy, and QP188 monotherapy resulted in a nonsignificant reduction in mean viral titers compared to P188 monotherapy (p = 0.08). CONCLUSION: Combining GCV with the excipients quercetin and P188 effectively ameliorated CMV-induced sensorineural hearing loss in a murine model. This result may be partially explained by a reduction in viral titers in mouse temporal bones that correlate with in vitro studies demonstrating additive antiviral effect in cell culture. LEVEL OF EVIDENCE: NA Laryngoscope, 134:1457-1463, 2024.
Assuntos
Infecções por Citomegalovirus , Surdez , Perda Auditiva , Animais , Camundongos , Ganciclovir/farmacologia , Ganciclovir/uso terapêutico , Citomegalovirus , Quercetina/farmacologia , Quercetina/uso terapêutico , Infecções por Citomegalovirus/complicações , Infecções por Citomegalovirus/tratamento farmacológico , Perda Auditiva/tratamento farmacológico , Antivirais/farmacologia , Antivirais/uso terapêuticoRESUMO
Hydroponic plant growth studies indicate that silver nanoparticles (Ag NPs) are phytotoxic. In this work, the phytotoxicity of commercial Ag NPs (10 nm) was evaluated in a sand growth matrix. Both NPs and soluble Ag were recovered from water extracts of the sand after growth of plants challenged with the commercial product; the surface charge of the Ag NPs in this extract was slightly reduced compared to the stock NPs. The Ag NPs reduced the length of shoots and roots of wheat in a dose-dependent manner. Furthermore, 2.5 mg/kg of the NPs increased branching in the roots of wheat (Triticum aestivum L.), thereby affecting plant biomass. Micron-sized (bulk) Ag particles (2.5 mg/kg) as well as Ag ions (63 µg Ag/kg) equivalent to the amount of soluble Ag in planted sand with Ag NPs (2.5 mg/kg) did not affect plant growth compared to control. In contrast, higher levels of Ag ions (2.5 mg/kg) reduced plant growth to a similar extent as the Ag NPs. Accumulation of Ag was detected in the shoots, indicating an uptake and transport of the metal from the Ag NPs in the sand. Transmision electron microscopy indicated that Ag NPs were present in shoots of plants with roots exposed to the Ag NPs or high levels of Ag ions. Both of these treatments caused oxidative stress in roots, as indicated by accumulation of oxidized glutathione, and induced expression of a gene encoding a metallothionein involved in detoxification by metal ion sequestration. Our findings demonstrate the potential effects of environmental contamination by Ag NPs on the metabolism and growth of food crops in a solid matrix.
Assuntos
Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Triticum/efeitos dos fármacos , Triticum/crescimento & desenvolvimento , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Brotos de Planta/efeitos dos fármacos , Brotos de Planta/crescimento & desenvolvimento , Dióxido de Silício/químicaRESUMO
The environmental fate of metal oxide particles as a function of size was assessed by comparing the behavior of CuO or ZnO nanoparticles (NPs) to that of the corresponding microparticles (MPs) in a sand matrix, with and without wheat (Triticum aestivum L.) growth. After 14 days of incubation in the planted sand, the CuO and ZnO NPs were increased from their nominal sizes of <50 nm and <100 nm, to ~317 nm and ~483 nm, respectively. Accordingly, the negative surface charge of colloids present in aqueous extracts from the sand amended with CuO (-27.0 mV) and ZnO (-10.0 mV) NPs was reduced by the presence of plants, to -19.8 mV and -6.0 mV, respectively. The surface charge of the MPs was not influenced by plants. Plant growth increased dissolution of NPs and MPs of both metal oxides in the sand from <0.3 mg/kg to about 1.0 mg/kg for the CuO products, and from ≤0.6 mg/kg to between 1.0 and 2.2 mg/kg for the Zn products. The NP or MP products reduced wheat root length by ~60% or ~50% from control levels; CuO was more toxic than ZnO. X-ray absorption spectroscopy (XAS) analysis showed that treatments with MPs or NPs of ZnO led to similar accumulations of Zn-phosphate species in the shoots, likely from dissolution of ZnO. Exposure to CuO NPs or MPs resulted in similar XAS spectra for Cu in the shoots explained by plant accumulation of both CuO and Cu(I)-sulfur complexes. These findings demonstrate the similarities between commercial NPs and MPs of CuO or ZnO in wheat plants, with greater root toxicity correlating with smaller particle size. Factors from the sand and the plant modified the aggregation or dissolution of both types of particles, thus, influencing their environmental fates.
Assuntos
Cobre/química , Nanopartículas , Plantas/química , Óxido de Zinco/química , Microscopia de Força Atômica , Solubilidade , Espectroscopia por Absorção de Raios XRESUMO
Fungal plant pathogens such as Fusarium graminearum cause severe global economic losses in cereals crops, and current control measures are limited. This work addresses the potential for ZnO nanoparticles (NPs) and biocontrol bacteria to be used in plant fungal control strategies. Growth of F. graminearum was significantly (p = 0.05) inhibited by inclusion of the NPs in a mung bean broth agar and in sand. Suspension in mung bean broth medium modified the surface charge, dissolution, and aggregation state of the ZnO NPs, in comparison to processes occurring in water suspension. The ZnO NPs were significantly more inhibitory to fungal growth than micro-sized particles of ZnO, although both types of particles released similar levels of soluble Zn, indicating size-dependent toxicity of the particles. Zn ions produced dose-dependent inhibition, noticeable at the level of soluble Zn released from NPs after seven-day suspension in medium; inhibitory levels caused acidification of the growth medium. Transfer of fungal inoculum after exposure to the ZnO NPs to fresh medium did not indicate adaptation to the stress because growth was still inhibited by the NPs. The ZnO NPs did not prevent metabolites from a biocontrol bacterium, Pseudomonas chlororaphis O6, from inhibiting Fusarium growth: no synergism was observed in the mung bean agar. Because other studies find that soil amendment with ZnO NPs required high doses for inhibition of plant growth, the findings of pathogen growth control reported in this paper open the possibility of using ZnO NP-based formulations to complement existing strategies for improving crop health in field settings.
Assuntos
Antifúngicos/farmacologia , Fusarium/efeitos dos fármacos , Nanopartículas/toxicidade , Controle Biológico de Vetores , Pseudomonas/fisiologia , Óxido de Zinco/farmacologia , Zinco/farmacologia , Ágar , Antibiose , Cátions Bivalentes , Meios de Cultura/química , Grão Comestível/microbiologia , Fabaceae/química , Fusarium/crescimento & desenvolvimento , Tamanho da PartículaRESUMO
OBJECTIVE: Fetal reduction (FR) in multiples dramatically improves outcomes. We prioritize FR decisions for health and historically declined to factor gender. As male preferences apparently diminished, our bioethicist encouraged a re-evaluation. METHODS: Three hundred ninety-six patients reducing triplets or twins were categorized as 3â2, 3â1, and 2â1, Major (M) anomaly or minor (m) anomaly, same gender (SG), and those for whom gender preference (GP) was possible. Higher order and non chorionic villus sampling were excluded. FR decisions were prioritized by M anomaly, Suspicious, or m anomaly. If neither, we considered GP. RESULTS: Of 319, 214 (67%) had either M/m or SG. Of those, 3â2 with gender option: 71/79 chose male and female or had no preferences, one chose male/male, and seven chose female/female. We reduced monochorionic twins in 33/35 3â1 cases. Of 20 with GP choice, 10 chose male and 10 chose female. Of 162 2â1, 54 had M or m, 50 were SG, but of the 44 M/F twins, 20 chose male and 24 chose female. CONCLUSIONS: There has been a cultural shift mostly preferring one of each or having no preference. When reducing to one, >50% prefer a girl. In addition to identifying abnormalities, chorionic villus sampling before FR expands patient autonomy.