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1.
Ecotoxicol Environ Saf ; 224: 112630, 2021 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-34392149

RESUMO

The second generation energy crop Miscanthus x giganteus (Mxg) was cultivated in pots with mixtures of clean and petroleum industry contaminated soil affected by petroleum, Pb, Zn contamination and high salinity. The survival rate reached 100%, nevertheless the biomass parameters were negatively affected even in the lowest proportion of contaminated soil. In the lowest contamination, where the plant grew still quite successfully, C10-C40 degradation was significantly enhanced compared to the unplanted control with degradation of 58 ± 14%. The plant contribution to aliphatics degradation was significantly correlated with biomass, thus it was negligible in higher contamination. A similar pattern was documented in development of the soil bacterial community. The shift in community structure after Mxg cultivation was observed mainly in the soil with the lowest contaminant proportion, though an increase of bacterial diversity in the miscanthus rhizosphere was observed in all cases. Relative abundance of Actinobacteria was reduced on behalf of several less abundant phyla (Verrucomicrobia, Bacterioides, Acidobacteria). The majority of genera identified as potential petroleum degraders (Pseudomonas, Shinella, Altererythrobacter, Azospirillum, Mesorhizobium, Dyella) were more abundant in contaminated soil with miscanthus, suggesting that Mxg could be a promising crop for phytomanagement of petroleum contaminated soils but salt phytotoxicity needs to be mitigated first.

2.
J Nurs Care Qual ; 34(1): 40-46, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-29889724

RESUMO

BACKGROUND: Nurse engagement is a modifiable element of the work environment and has shown promise as a potential safety intervention. PURPOSE: Our study examined the relationship between the level of engagement, staffing, and assessments of patient safety among nurses working in hospital settings. METHODS: A secondary analysis of linked cross-sectional data was conducted using survey data of 26 960 nurses across 599 hospitals in 4 states. Logistic regression models were used to examine the association between nurse engagement, staffing, and nurse assessments of patient safety. RESULTS: Thirty-two percent of nurses gave their hospital a poor or failing patient safety grade. In 25% of hospitals, nurses fell in the least or only somewhat engaged categories. A 1-unit increase in engagement lowered the odds of an unfavorable safety grade by 29% (P < .001). Hospitals where nurses reported higher levels of engagement were 19% (P < .001) less likely to report that mistakes were held against them. Nurses in poorly staffed hospitals were 6% more likely to report that important information about patients "fell through the cracks" when transferring patients across units (P < .001). CONCLUSIONS: Interventions to improve nurse engagement and adequate staffing serve as strategies to improve patient safety.


Assuntos
Recursos Humanos de Enfermagem Hospitalar/provisão & distribuição , Segurança do Paciente , Admissão e Escalonamento de Pessoal , Qualidade da Assistência à Saúde/estatística & dados numéricos , Estudos Transversais , Hospitais , Humanos , Recursos Humanos de Enfermagem Hospitalar/psicologia , Inquéritos e Questionários , Local de Trabalho/psicologia
3.
J Environ Qual ; 46(2): 384-392, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28380560

RESUMO

Constructed wetland treatment systems are used to remove selenium (Se) from flue-gas desulfurization (FGD) wastewater (WW). However, direct confirmation of the mechanism responsible for FGD WW Se retention in soil is lacking. A laboratory-based soil column study was performed to develop an evidence-based mechanism of Se retention and to study the behavior and the retention capacity of FGD WW constituents in water-saturated soil. A deoxygenated 1:1 mixture of FGD WW and raw water was delivered to the columns bottom-up at a flux of 1.68 cm d for 100 d. Some of the columns were flushed with the raw water at the same rate for an additional 100 d. Column effluent was analyzed for constituents of concern. Results showed a complete retention of FGD WW Se in the soil materials. Boron and fluorine were partially retained; however, sulfur, sodium, and chlorine retention was poor, agreeing with field observations. The FGD WW Se was retained in soil near the inlet end of the columns, indicating its limited mobility under reduced conditions. Sequential extraction procedure revealed that retained Se was mainly sequestered as stable/residual forms. Bulk- and micro-X-ray absorption near-edge structure spectroscopy confirmed that Se was mainly retained as reduced/stable species [Se(IV), organic Se, and Se(0)]. This study provides direct evidence for FGD WW Se retention in water-saturated soil via the transformation of oxidized Se into reduced/stable forms.


Assuntos
Selênio/química , Águas Residuárias , Purificação da Água , Selênio/análise , Solo , Poluentes do Solo , Água , Áreas Alagadas
4.
J Neurosci ; 33(22): 9364-84, 2013 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-23719805

RESUMO

In vitro studies suggest that the intracellular C terminus of Neuroligin1 (NL1) could play a central role in the maturation of excitatory synapses. However, it is unknown how this activity affects synapses in vivo, and whether it may impact the development of complex behaviors. To determine how NL1 influences the state of glutamatergic synapses in vivo, we compared the synaptic and behavioral phenotypes of mice overexpressing a full-length version of NL1 (NL1FL) with mice overexpressing a version missing part of the intracellular domain (NL1ΔC). We show that overexpression of full-length NL1 yielded an increase in the proportion of synapses with mature characteristics and impaired learning and flexibility. In contrast, the overexpression of NL1ΔC increased the number of excitatory postsynaptic structures and led to enhanced flexibility in mnemonic and social behaviors. Transient overexpression of NL1FL revealed that elevated levels are not necessary to maintain synaptic and behavioral states altered earlier in development. In contrast, overexpression of NL1FL in the fully mature adult was able to impair normal learning behavior after 1 month of expression. These results provide the first evidence that NL1 significantly impacts key developmental processes that permanently shape circuit function and behavior, as well as the function of fully developed neural circuits. Overall, these manipulations of NL1 function illuminate the significance of NL1 intracellular signaling in vivo, and enhance our understanding of the factors that gate the maturation of glutamatergic synapses and complex behavior. This has significant implications for our ability to address disorders such as autism spectrum disorders.


Assuntos
Comportamento Animal/fisiologia , Moléculas de Adesão Celular Neuronais/fisiologia , Sistemas do Segundo Mensageiro/fisiologia , Sinapses/fisiologia , Animais , Córtex Auditivo/crescimento & desenvolvimento , Córtex Auditivo/fisiologia , Western Blotting , Moléculas de Adesão Celular Neuronais/genética , Espinhas Dendríticas/fisiologia , Espinhas Dendríticas/ultraestrutura , Doxiciclina/farmacologia , Fenômenos Eletrofisiológicos , Proteínas de Fluorescência Verde , Humanos , Processamento de Imagem Assistida por Computador , Imuno-Histoquímica , Deficiências da Aprendizagem/genética , Deficiências da Aprendizagem/psicologia , Aprendizagem em Labirinto/fisiologia , Camundongos , Camundongos Transgênicos , Microscopia Confocal , Desempenho Psicomotor/efeitos dos fármacos , Desempenho Psicomotor/fisiologia , Reconhecimento Psicológico , Comportamento Social , Predomínio Social , Sinaptossomos/fisiologia
5.
Artigo em Inglês | MEDLINE | ID: mdl-37782454

RESUMO

Past and recent applications of 2,4,6-trinitrotoluene (TNT) in military and civilian industries have led to contamination of soil and marine ecosystems. Among various TNT remediation techniques, biological remediation is widely accepted for its sustainability, low cost, and scalable applications. This study was designed to isolate a fungus strain from a TNT-contaminated soil to investigate its tolerance to and potential for removal of TNT. Thus, a soil column with a history of periodic TNT amendment was used to isolate dominant strains of fungi Fusarium solani isolate, which is not commonly reported for TNT mineralization and was found predominant in the subsurface layer of the TNT-amended soil. F. solani was investigated for TNT concentration tolerance at 30, 70, and 100 mg/L on agar plates and for TNT removal in liquid cultures at the same given concentrations. F. solani activity was compared with that of a reference soil-born fungus that has been intensively studied for TNT removal (Phanerochaete chrysosporium) obtained from the American Type Culture Collection. On agar media, F. solani showed a larger colony diameter than P. chrysosporium at similar TNT concentrations, indicating its high potential to tolerate toxic levels of TNT as found in contaminated sites. In the liquid culture medium, F. solani was able to significantly produce higher biomass than P. chrysosporium in all TNT concentrations. The TNT removal percentage from the liquid culture at the highest TNT concentration of 100 mg/L reached about 85% with F. solani, while P. chrysosporium was no better than 25% at the end of an 84-h incubation period. Results indicate a significant potential of using F. solani in the bioremediation of polluted TNT soils that overcome the high concentration barrier in the field. However, further investigation is needed to identify enzymatic potential and the most effective applications and possible limitations of this method on a large scale.

6.
Radiology ; 279(3): 670-2, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27183403
7.
J Environ Qual ; 50(5): 1220-1232, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34273114

RESUMO

Military activities can contaminate productive land with potentially toxic substances. The most common trace metal contaminant on military bases is lead (Pb). A field experiment was begun in 2016 at Fort Riley, KS, in an area with total soil Pb concentrations ranging from 900 to 1,500 mg kg-1 and near-neutral pH. The main objectives were to test the potential of Miscanthus sp. for phytostabilization of the site and to evaluate the effects of soil amendments on Miscanthus growth, soil-plant Pb transfer, bioaccessibility of soil Pb, and soil health. The experimental design was a randomized complete block, with five treatments and four replications. Treatments were (a) existing vegetation; (b) Miscanthus planted in untilled soil, no amendments; (c) Miscanthus planted in tilled soil; (d) Miscanthus planted in tilled soil amended with inorganic P (triple superphosphate applied at 5:3 Pb:P); and (e) Miscanthus planted in tilled soil amended with organic P (Class B biosolids applied at 45 Mg ha-1 ). Tilling and soil amendments increased dry matter yields only in the establishment year. Total Pb uptake, plant tissue Pb concentration, and soil Pb bioaccessibility were significantly less in the Miscanthus plots amended with biosolids than the Miscanthus plots with no added P across all 3 yr. Enzyme activities, organic carbon, and microbial biomass were also greater in biosolids-treated plots. Results show that planting-time addition of soil amendments to Pb-contaminated soil supported Miscanthus establishment, stabilized and reduced bioaccessibility of soil Pb, reduced concentration and uptake of Pb by Miscanthus, and enhanced soil health parameters.


Assuntos
Metais Pesados , Militares , Poluentes do Solo , Biodegradação Ambiental , Humanos , Metais Pesados/análise , Solo , Poluentes do Solo/análise
8.
Am J Otolaryngol ; 30(4): 244-9, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19563935

RESUMO

OBJECTIVES: Although intensified therapy has contributed to improved outcomes for patients with head and neck cancer, acute toxicity has increased as well. To lessen the severity of nutritional compromise in these patients, our institutional protocol has been to routinely place feeding tubes before the initiation of therapy. This investigation details the toxicities associated with feeding tube placement and predictors for duration of tube dependence. MATERIALS AND METHODS: The records of the Radiation Oncology Department at Emory Clinic were reviewed for patients receiving definitive radiotherapy between 6/1/2003 and 6/1/2006. The records of the subset of patients with feeding tube placement before the initiation of therapy were then reviewed for toxicities as well as length of time of tube dependence. RESULTS: There were 102 eligible patients. Radiotherapy was delivered with concomitant chemotherapy in all. Median time with feeding tube in place for all patients was 4.4 months (range, 0.2-28.9 months). For 82 patients with eventual tube removal, the median time of tube dependence was 3.8 months (range, 1.4-28.9 months). Risk factors for prolonged tube dependence are analyzed; on multivariate analysis, patient age, T stage, and nodal status remained significant. The most common complication was tube replacement, with 11.8% of all tubes requiring replacement. Infection and pain occurred in 8.8% and 5.9% of patients, respectively. CONCLUSION: Feeding tubes are required for more than 2 months after combined modality treatment of head and neck cancer. They are generally well tolerated, but toxicities are not trivial: more than 10% require replacement and more than 8% of patients develop infection at the insertion site. We are assessing their routine placement in light of these data.


Assuntos
Antineoplásicos/uso terapêutico , Nutrição Enteral/instrumentação , Neoplasias de Cabeça e Pescoço/terapia , Adulto , Idoso , Feminino , Seguimentos , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Neoplasias de Cabeça e Pescoço/radioterapia , Humanos , Masculino , Pessoa de Meia-Idade , Radioterapia Adjuvante , Estudos Retrospectivos , Resultado do Tratamento
9.
Environ Pollut ; 249: 330-337, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30903832

RESUMO

This study aims to summarize results on potential phytomanagement of two metal(loid)-polluted military soils using Miscanthus x giganteus. Such an option was tested during 2-year pot experiments with soils taken from former military sites in Sliac, Slovakia and Kamenetz-Podilsky, Ukraine. The following elements were considered: As, Cu, Fe, Mn, Pb, Sr, Ti, Zn and Zr. M. x giganteus showed good growth at both military soils with slightly higher maximum shoot lengths in the second year of vegetation. Based on Principal Component Analysis similarities of metal(loid) uptake by roots, stems and leaves were summarized. Major part of the elements remained in M. x giganteus roots and rather limited amounts moved to the aerial parts. Levels taken up decreased in the second vegetation year. Dynamics of foliar metal(loid) concentrations divided the elements in two groups: essential elements required for metabolism (Fe, Mn, Cu, and Zn) and non-essential elements without any known metabolic need (As, Sr, Ti, and Zr). Fe, Mn, Ti and Sr showed similar S-shaped uptake curve in terms of foliar concentrations (likely due to dilution in growing biomass), while Cu exhibited a clear peak mid-season. Behavior of Zn was in between. Foliar Zr and As concentrations were below detection limit. The results illustrated a good potential of M. x giganteus for safely growing on metal-polluted soils taken from both military localities.


Assuntos
Biocombustíveis , Recuperação e Remediação Ambiental/métodos , Poluentes do Solo/análise , Biodegradação Ambiental , Biomassa , Poluentes Ambientais/análise , Metais/análise , Raízes de Plantas/metabolismo , Poaceae/metabolismo , Eslováquia , Solo
10.
J Digit Imaging ; 21(4): 384-9, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17554582

RESUMO

Continuous voice recognition dictation systems for radiology reporting provide a viable alternative to conventional transcription services with the promise of shorter report turnaround times and increased cost savings. While these benefits may be realized in academic institutions, it is unclear how voice recognition dictation impacts the private practice radiologist who is now faced with the additional task of transcription. In this article, we compare conventional transcription services with a commercially available voice recognition system with the following results: 1) Reports dictated with voice recognition took 50% longer to dictate despite being 24% shorter than those conventionally transcribed, 2) There were 5.1 errors per case, and 90% of all voice recognition dictations contained errors prior to report signoff while 10% of transcribed reports contained errors. 3). After signoff, 35% of VR reports still had errors. Additionally, cost savings using voice recognition systems in non-academic settings may not be realized. Based on average radiologist and transcription salaries, the additional time spent dictating with voice recognition costs an additional $6.10 per case or $76,250.00 yearly. The opportunity costs may be higher. Informally surveyed, all radiologists expressed dissatisfaction with voice recognition with feelings of frustration, and increased fatigue. In summary, in non-academic settings, utilizing radiologists as transcriptionists results in more error ridden radiology reports and increased costs compared with conventional transcription services.


Assuntos
Prontuários Médicos , Padrões de Prática Médica/organização & administração , Sistemas de Informação em Radiologia , Radiologia/estatística & dados numéricos , Interface para o Reconhecimento da Fala , Interface Usuário-Computador , Adulto , Idoso , Idoso de 80 Anos ou mais , Análise Custo-Benefício , Humanos , Satisfação no Emprego , Prontuários Médicos/estatística & dados numéricos , Pessoa de Meia-Idade , Prática Privada/estatística & dados numéricos , Sistemas de Informação em Radiologia/estatística & dados numéricos , Interface para o Reconhecimento da Fala/estatística & dados numéricos , Tempo , Simplificação do Trabalho , Adulto Jovem
11.
J Agric Food Chem ; 55(26): 10517-30, 2007 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-18047282

RESUMO

Synchrotron radiation infrared microspectroscopy (SR-IMS) permits the direct analysis of plant cell-wall architecture at the cellular level in situ, combining spatially localized information and chemical information from IR absorbances to produce a chemical map that can be linked to a particular morphology or functional group. This study demonstrated the use of SR-IMS to probe biopolymers, such as cellulose, lignin, and proteins, in the root tissue of hydroponically grown sunflower and maize plants. Principal components analysis (PCA) was employed to reveal the major spectral variance between maize and sunflower plant tissues. The use of PCA showed distinct separation of maize and sunflower samples using the IR spectra of the epidermis and xylem. The infrared band at 1635 cm(-1), representing hydrocinnamic acid in (H type) lignin, provided a conclusive means of distinguishing between maize and sunflower plant tissues.


Assuntos
Helianthus/anatomia & histologia , Raízes de Plantas/anatomia & histologia , Espectrofotometria Infravermelho/métodos , Zea mays/anatomia & histologia , Hidroponia , Xilema/anatomia & histologia
12.
Med Dosim ; 32(4): 287-94, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17980830

RESUMO

Implementation of daily kilovoltage imaging for setup verification improves the reproducibility of treatment by eliminating small random setup errors. We evaluate the dosimetric consequences of such shifts, not yet evaluated, in a group of head-and-neck cancer patients (ENT) treated with intensity modulated radiation therapy (IMRT) at Emory University. Twelve patients with ENT malignancies were analyzed. On-Board Imaging (OBI) was used in at least 70% of each patient's treatment sessions. An isodose distribution was generated for each fraction, with the isocenter shifted to its calculated location prior to OBI repositioning. These plans were summed and then compared to the simulation plan for coverage of target structures. For these 12 patients, there were a total of 18 planning target volumes (PTV). The mean (range) percent reduction in minimum dose was 12.1% (-1.0 to 43.3). For 10 right necks and 9 left necks treated, the mean percent reduction in minimum dose was 11.8% (-0.6 to 39.7) and 13.3% (-3.6 to 31.2), respectively. The mean reduction in mean dose to the PTV was 1.3% (0 to 5.1). The mean reduction in mean dose to the right and left necks was 1.0% (0.2 to 3.9) and 1.13% (0.4 to 3.4), respectively. From this analysis, we conclude that the shifts made were small and random, with essentially no change in mean dose delivered to target structures. There is, however, significant improvement in the minimum dose delivered. Underdosing even a small portion of the tumor potentially sacrifices the probability of local control; correcting these setup errors seems desirable.


Assuntos
Neoplasias de Cabeça e Pescoço/radioterapia , Dosagem Radioterapêutica , Radioterapia de Intensidade Modulada/métodos , Idoso , Tronco Encefálico/efeitos da radiação , Cóclea/efeitos da radiação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tomografia por Emissão de Pósitrons , Glândulas Salivares/efeitos da radiação , Medula Espinal/efeitos da radiação , Tomografia Computadorizada por Raios X
14.
Int J Radiat Oncol Biol Phys ; 61(5): 1385-92, 2005 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-15817341

RESUMO

PURPOSE: To compare the gross tumor volume (GTV) identified on CT to that obtained from fluorodeoxyglucose (FDG) positron emission tomography (PET) and determine the differences in volume and dose coverage of the PET-GTV when the CT-GTV is used for radiotherapy planning. METHODS AND MATERIALS: A total of 40 patients with intact squamous cell carcinoma arising in the head-and-neck region underwent intensity-modulated radiotherapy (IMRT) at one department. All patients underwent CT simulation for treatment planning followed by PET-CT in the treatment position. CT simulation images were fused to the CT component of the PET-CT images. The GTV using the CT simulation images was contoured (CT-GTV), as was the GTV based on the PET scan (PET-GTV). The IMRT plans were obtained using the CT-GTV. RESULTS: The PET-GTV was smaller, the same size, and larger than the CT-GTV in 30 (75%), 3 (8%), and 7 (18%) cases respectively. The median PET-GTV and CT-GTV volume was 20.3 cm(3) (range, 0.2-294) and 37.2 cm(3) (range, 2-456), respectively. The volume of PET-GTV receiving at least 95% of the prescribed dose was 100% in 20 (50%), 95-99% in 10 (25%), 90-94% in 3 (8%), 85-89% in 1 (3%), 80-84% in 2 (5%), 75-79% in 1 (3%), and <75% in 3 (8%) cases. The minimal dose received by 95% of the PET-GTV was >/=100% in 19 (48%), 95-99% in 11 (28%), 90-94% in 5 (13%), 85-89% in 2 (5%), and <75% in 3 (8%) cases. CONCLUSION: The PET-GTV was larger than the CT-GTV in 18% of cases. In approximately 25% of patients with intact head-and-neck cancer treated using IMRT, the volume of PET-GTV receiving at least 95% of the prescribed dose and minimal dose received by 95% of the PET-GTV were less than optimal.


Assuntos
Carcinoma de Células Escamosas/diagnóstico por imagem , Neoplasias de Cabeça e Pescoço/diagnóstico por imagem , Tomografia por Emissão de Pósitrons , Radioterapia Conformacional/métodos , Tomografia Computadorizada por Raios X , Adulto , Idoso , Carcinoma de Células Escamosas/radioterapia , Simulação por Computador , Feminino , Fluordesoxiglucose F18 , Neoplasias de Cabeça e Pescoço/radioterapia , Humanos , Masculino , Pessoa de Meia-Idade , Compostos Radiofarmacêuticos , Planejamento da Radioterapia Assistida por Computador
15.
Biotechnol Adv ; 23(4): 283-333, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15848039

RESUMO

Plant secondary metabolites are unique sources for pharmaceuticals, food additives, flavors, and other industrial materials. Accumulation of such metabolites often occurs in plants subjected to stresses including various elicitors or signal molecules. Understanding signal transduction paths underlying elicitor-induced production of secondary metabolites is important for optimizing their commercial production. This paper summarizes progress made on several aspects of elicitor signal transduction leading to production of plant secondary metabolites, including: elicitor signal perception by various receptors of plants; avirulence determinants and corresponding plant R proteins; heterotrimeric and small GTP binding proteins; ion fluxes, especially Ca2+ influx, and Ca2+ signaling; medium alkalinization and cytoplasmic acidification; oxidative burst and reactive oxygen species; inositol trisphosphates and cyclic nucleotides (cAMP and cGMP); salicylic acid and nitric oxide; jasmonate, ethylene, and abscisic acid signaling; oxylipin signals such as allene oxide synthase-dependent jasmonate and hydroperoxide lyase-dependent C12 and C6 volatiles; as well as other lipid messengers such as lysophosphatidylcholine, phosphatidic acid, and diacylglycerol. All these signal components are employed directly or indirectly by elicitors for induction of plant secondary metabolite accumulation. Cross-talk between different signaling pathways is very common in plant defense response, thus the cross-talk amongst these signaling pathways, such as elicitor and jasmonate, jasmonate and ethylene, and each of these with reactive oxygen species, is discussed separately. This review also highlights the integration of multiple signaling pathways into or by transcription factors, as well as the linkage of the above signal components in elicitor signaling network through protein phosphorylation and dephosphorylation. Some perspectives on elicitor signal transduction and plant secondary metabolism at the transcriptome and metabolome levels are also presented.


Assuntos
Regulação da Expressão Gênica de Plantas/fisiologia , Metabolismo dos Lipídeos , Modelos Biológicos , Proteínas de Plantas/metabolismo , Plantas/metabolismo , Transdução de Sinais/fisiologia , Fatores de Transcrição/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Complexos Multienzimáticos/metabolismo , Plantas/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos
16.
Radiat Prot Dosimetry ; 115(1-4): 508-12, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16381776

RESUMO

Secondary neutron dose-equivalents were determined for conventional and intensity modulated radiation therapy (IMRT) prostate treatments for 15 and 18 MV X-ray beams. Conventional and IMRT treatment plans were generated to deliver 45 Gy to the prostate, seminal vessicles and external and internal iliac lymph nodes. Neutron spectra were determined by unfolding measurements from a TLD-based Bonner sphere system. Treatments using 18 MV IMRT and conventional plans result in neutron ambient dose-equivalents of 687 and 112 mSv, respectively. Delivery of the 15 MV IMRT and conventional plans results in neutron ambient dose-equivalents of 327 and 52 mSv, respectively. The data illustrate that using lower photon energies for IMRT reduces the secondary neutron dose, while still achieving comparable treatment volume coverage and sparing critical normal tissue.


Assuntos
Nêutrons , Lesões por Radiação/prevenção & controle , Proteção Radiológica/métodos , Radiometria/métodos , Radioterapia de Intensidade Modulada/efeitos adversos , Radioterapia de Intensidade Modulada/métodos , Medição de Risco/métodos , Carga Corporal (Radioterapia) , Simulação por Computador , Relação Dose-Resposta à Radiação , Humanos , Transferência Linear de Energia , Modelos Biológicos , Lesões por Radiação/etiologia , Dosagem Radioterapêutica , Eficiência Biológica Relativa , Fatores de Risco
17.
Insect Biochem Mol Biol ; 59: 58-71, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25701385

RESUMO

Members of the multicopper oxidase (MCO) family of enzymes can be classified by their substrate specificity; for example, ferroxidases oxidize ferrous iron, ascorbate oxidases oxidize ascorbate, and laccases oxidize aromatic substrates such as diphenols. Our previous work on an insect multicopper oxidase, MCO1, suggested that it may function as a ferroxidase. This hypothesis was based on three lines of evidence: RNAi-mediated knock down of Drosophila melanogaster MCO1 (DmMCO1) affects iron homeostasis, DmMCO1 has ferroxidase activity, and DmMCO1 has predicted iron binding residues. In our current study, we expanded our focus to include MCO1 from Anopheles gambiae, Tribolium castaneum, and Manduca sexta. We verified that MCO1 orthologs have similar expression profiles, and that the MCO1 protein is located on the basal surface of cells where it is positioned to oxidize substrates in the hemolymph. In addition, we determined that RNAi-mediated knock down of MCO1 in A. gambiae affects iron homeostasis. To further characterize the enzymatic activity of MCO1 orthologs, we purified recombinant MCO1 from all four insect species and performed kinetic analyses using ferrous iron, ascorbate and two diphenols as substrates. We found that all of the MCO1 orthologs are much better at oxidizing ascorbate than they are at oxidizing ferrous iron or diphenols. This result is surprising because ascorbate oxidases are thought to be specific to plants and fungi. An analysis of three predicted iron binding residues in DmMCO1 revealed that they are not required for ferroxidase or laccase activity, but two of the residues (His374 and Asp380) influence oxidation of ascorbate. These two residues are conserved in MCO1 orthologs from insects and crustaceans; therefore, they are likely to be important for MCO1 function. The results of this study suggest that MCO1 orthologs function as ascorbate oxidases and influence iron homeostasis through an unknown mechanism.


Assuntos
Anopheles/enzimologia , Ascorbato Oxidase/metabolismo , Proteínas de Insetos/metabolismo , Manduca/enzimologia , Tribolium/enzimologia , Sequência de Aminoácidos , Animais , Ácido Ascórbico/química , Ceruloplasmina/química , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/enzimologia , Compostos Ferrosos/química , Hemolinfa/enzimologia , Proteínas de Insetos/genética , Cinética , Dados de Sequência Molecular , Oxirredução , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Alinhamento de Sequência , Especificidade da Espécie , Especificidade por Substrato
18.
AJNR Am J Neuroradiol ; 25(5): 670-6, 2004 May.
Artigo em Inglês | MEDLINE | ID: mdl-15140704

RESUMO

BACKGROUND AND PURPOSE: Several white matter tracts in the brain cannot be identified on MR studies because they are indistinguishable from the surrounding white matter. We sought to develop a method to precisely localize white matter tracts by correlating anatomic dissections with corresponding MR images. METHODS: MR imaging was used to guide anatomic dissection of the uncinate fasciculus. Formalin-preserved brains were imaged before and after several stages of dissection. Progressive dissection was guided by using volume-rendered and cross-sectional images of the dissected specimens. To precisely define the location of a tract, its surface was traced on the corresponding three-dimensional MR image of the dissected specimen. MR images of the dissected and intact specimens were coregistered to allow the tracings to be projected onto multiplanar reformatted images of the intact specimen. RESULTS: The uncinate fasciculus in the anterior temporal lobe and external and extreme capsules was dissected without destroying adjacent structures. Coregistration of the MR images from intact and dissected specimens permitted precise MR identification of the surface of this tract. These methods were successful for two additional tracts. (The dissected anatomy, MR anatomy, and clinical examples of the three tracts are described in a companion article.) CONCLUSION: MR-assisted anatomic dissection permits limited removal of brain tissue so that important anatomic and surgical relationships can be demonstrated on correlated MR studies. This method can be applied to other white matter tracts that are indistinguishable on MR studies and to situations in which anatomic validation of normal and abnormal diffusion tractographic studies is needed.


Assuntos
Imageamento por Ressonância Magnética , Lobo Temporal/anatomia & histologia , Adulto , Cadáver , Dissecação/métodos , Humanos , Neurologia/métodos
19.
AJNR Am J Neuroradiol ; 25(5): 677-91, 2004 May.
Artigo em Inglês | MEDLINE | ID: mdl-15140705

RESUMO

BACKGROUND AND PURPOSE: The MR anatomy of the uncinate fasciculus, inferior occipitofrontal fasciculus, and Meyer's loop of the optic radiation, which traverse the temporal stem, is not well known. The purpose of this investigation was to study these structures in the anterior temporal lobe and the external and extreme capsules and to correlate the dissected anatomy with the cross-sectional MR anatomy. METHODS: Progressive dissection was guided by three-dimensional MR renderings and cross-sectional images. Dissected segments of the tracts and the temporal stem were traced and projected onto reformatted images. The method of dissection tractography is detailed in a companion article. RESULTS: The temporal stem extends posteriorly from the level of the amygdala to the level of the lateral geniculate body. The uncinate and inferior occipitofrontal fasciculi pass from the temporal lobe into the extreme and external capsules via the temporal stem. Meyer's loop extends to the level of the amygdala, adjacent to the uncinate fasciculus and anterior commissure. These anatomic features were demonstrated on correlative cross-sectional MR images and compared with clinical examples. CONCLUSION: This study clarified the MR anatomy of the uncinate and inferior occipitofrontal fasciculi and Meyer's loop in the temporal stem and in the external and extreme capsules, helping to explain patterns of tumor spread. The inferior occipitofrontal fasciculus is an important yet previously neglected tract. These results provide a solid anatomic foundation for diffusion tractography of the normal temporal stem and its tracts, as well as their abnormalities in brain disorders such as epilepsy, postoperative complications, trauma, schizophrenia, and Alzheimer disease.


Assuntos
Imageamento por Ressonância Magnética , Lobo Temporal/anatomia & histologia , Cadáver , Dissecação/métodos , Humanos , Neurologia/métodos
20.
Kennedy Inst Ethics J ; 2(2): 137-58, 1992 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11645742

RESUMO

Somatic cell gene therapy has yielded promising results. If germ cell gene therapy can be developed, the promise is even greater: hundreds of genetic diseases might be virtually eliminated. But some claim the procedure is morally unacceptable. We thoroughly and sympathetically examine several possible reasons for this claim but find them inadequate. There is no moral reason, then, not to develop and employ germ-line gene therapy. Taking the offensive, we argue next that medicine has a prima facie moral obligation to do so.


Assuntos
Ética , Terapia Genética , Células Germinativas , Medição de Risco , Risco , Embrião de Mamíferos , Eugenia (Ciência) , Doenças Genéticas Inatas , Características Humanas , Direitos Humanos , Humanos , Consentimento Livre e Esclarecido , Métodos , Obrigações Morais , Assistência ao Paciente , Justiça Social , Responsabilidade Social , Argumento Refutável
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