RESUMEN
Large-scale terrestrial carbon (C) estimating studies using methods such as atmospheric inversion, biogeochemical modeling, and field inventories have produced different results. The goal of this study was to integrate fine-scale processes including land use and land cover change into a large-scale ecosystem framework. We analyzed the terrestrial C budget of the conterminous United States from 1971 to 2015 at 1-km resolution using an enhanced dynamic global vegetation model and comprehensive land cover change data. Effects of atmospheric CO2 fertilization, nitrogen deposition, climate, wildland fire, harvest, and land use/land cover change (LUCC) were considered. We estimate annual C losses from cropland harvest, forest clearcut and thinning, fire, and LUCC were 436.8, 117.9, 10.5, and 10.4 TgC/year, respectively. C stored in ecosystems increased from 119,494 to 127,157 TgC between 1971 and 2015, indicating a mean annual net C sink of 170.3 TgC/year. Although ecosystem net primary production increased by approximately 12.3 TgC/year, most of it was offset by increased C loss from harvest and natural disturbance and increased ecosystem respiration related to forest aging. As a result, the strength of the overall ecosystem C sink did not increase over time. Our modeled results indicate the conterminous US C sink was about 30% smaller than previous modeling studies, but converged more closely with inventory data.
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Carbono , Ecosistema , Carbono/análisis , Secuestro de Carbono , Clima , Cambio Climático , Bosques , Estados UnidosRESUMEN
Many studies project future bird ranges by relying on correlative species distribution models. Such models do not usually represent important processes explicitly related to climate change and harvesting, which limits their potential for predicting and understanding the future of boreal bird assemblages at the landscape scale. In this study, we attempted to assess the cumulative and specific impacts of both harvesting and climate-induced changes on wildfires and stand-level processes (e.g., reproduction, growth) in the boreal forest of eastern Canada. The projected changes in these landscape- and stand-scale processes (referred to as "drivers of change") were then assessed for their impacts on future habitats and potential productivity of black-backed woodpecker (BBWO; Picoides arcticus), a focal species representative of deadwood and old-growth biodiversity in eastern Canada. Forest attributes were simulated using a forest landscape model, LANDIS-II, and were used to infer future landscape suitability to BBWO under three anthropogenic climate forcing scenarios (RCP 2.6, RCP 4.5 and RCP 8.5), compared to the historical baseline. We found climate change is likely to be detrimental for BBWO, with up to 92% decline in potential productivity under the worst-case climate forcing scenario (RCP 8.5). However, large declines were also projected under baseline climate, underlining the importance of harvest in determining future BBWO productivity. Present-day harvesting practices were the single most important cause of declining areas of old-growth coniferous forest, and hence appeared as the single most important driver of future BBWO productivity, regardless of the climate scenario. Climate-induced increases in fire activity would further promote young, deciduous stands at the expense of old-growth coniferous stands. This suggests that the biodiversity associated with deadwood and old-growth boreal forests may be greatly altered by the cumulative impacts of natural and anthropogenic disturbances under a changing climate. Management adaptations, including reduced harvesting levels and strategies to promote coniferous species content, may help mitigate these cumulative impacts.
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Cambio Climático , Ecosistema , Bosques , Animales , Aves , Canadá , Especificidad de la EspecieRESUMEN
We report the case of a 66 year old female with a supratrigonal vesicovaginal fistula (VVF) that developed after undergoing radical hysterectomy, chemotherapy and pelvic radiation therapy for advanced cervical cancer. VVF repairs in an irradiated field are known to be complicated procedures with significant morbidity and a high rate of failure due to the effect of radiation. Amniotic membranes have been demonstrated to improve healing rates in difficult to heal wounds. To decrease morbidity a minimally invasive robotic procedure was performed and a dehydrated amniotic allograft patch was used to augment tissue healing. The VVF was repaired using the da Vinci Surgical System and the amniotic membrane was used as an interposition patch over the repair. There were no operative or postoperative complications and the patient was discharged home on postoperative day one. A cystogram performed 3 weeks postoperatively demonstrated a healed fistula. Follow-up at 5 months revealed no incontinence. This is the first reported case of a robotic VVF repair performed in an irradiated pelvis and the first use of an amniotic membrane allograft in the repair a VVF.
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Aloinjertos/cirugía , Aloinjertos/trasplante , Amnios/cirugía , Amnios/trasplante , Procedimientos Quirúrgicos Robotizados/métodos , Fístula Vesicovaginal/cirugía , Anciano , Femenino , HumanosRESUMEN
Changes in climate and atmospheric CO2 and nitrogen (N) over the last several decades have induced significant effects on forest carbon (C) cycling. However, contributions of individual factors are largely unknown because of the lack of long observational data and the undifferentiating between intrinsic factors and external forces in current ecosystem models. Using over four decades (1956-2001) of forest inventory data at 3432 permanent samples in maritime and boreal regions of British Columbia (B.C.), Canada, growth enhancements were reconstructed and partitioned into contributions of climate, CO2 and N after removal of age effects. We found that climate change contributed a particularly large amount (over 70%) of the accumulated growth enhancement, while the remaining was attributed to CO2 and N, respectively. We suggest that climate warming is contributing a widespread growth enhancement in B.C.'s forests, but ecosystem models should consider CO2 and N fertilization effects to fully explain inventory-based observations.
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Atmósfera , Carbono/química , Bosques , Nitrógeno/química , Árboles/crecimiento & desarrollo , Canadá , Cambio Climático , Ecosistema , Modelos Biológicos , Modelos Teóricos , Suelo/química , Factores de TiempoRESUMEN
BACKGROUND AND OBJECTIVE: There are limited national data on pediatric health information technology adoption rates. Our objective was to determine pediatricians' adoption rates of electronic health record systems (EHRs), barriers to adoption, and features of the systems adopted. METHODS: A survey of 1620 randomly selected US members of the American Academy of Pediatrics from February to July 2009 addressed use of EHRs and barriers to adoption. Bivariate analysis and logistic regression were used to determine associations between EHR use and various physician and practice characteristics. RESULTS: Six hundred forty-six postresidency pediatric clinicians practicing in office- or clinic-based settings responded (57.2%). Self-reported electronic medical record/EHR use was 54%/41%, but far fewer used systems that met the definition of a basic (25%) or fully functional (6%) EHR. Only 3% used a system that was fully functional and pediatric-supportive. Pediatricians practicing in multispecialty practices and those in hospital-based practices were more likely to use basic or fully functional EHRs than those in solo/2-physician practices. More than half of respondents reported financial barriers to implementing EHRs, and more than one-third were concerned about whether systems could meet their needs and whether an EHR would affect productivity. CONCLUSIONS: Pediatric adoption of fully functional EHRs lags general adoption. Barriers to adoption include financial and productivity concerns, but pediatricians are also concerned about finding systems that meet their needs. Few pediatricians use a system that is pediatric-supportive. To help identify pediatric-supportive systems, EHR certification efforts should include these requirements.
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Registros Electrónicos de Salud/estadística & datos numéricos , Pediatría/estadística & datos numéricos , Adulto , Actitud del Personal de Salud , Actitud hacia los Computadores , Niño , Análisis Costo-Beneficio , Recolección de Datos , Eficiencia , Registros Electrónicos de Salud/economía , Femenino , Práctica de Grupo/estadística & datos numéricos , Sistemas Prepagos de Salud/estadística & datos numéricos , Humanos , Masculino , Persona de Mediana Edad , Servicio Ambulatorio en Hospital/estadística & datos numéricos , Pediatría/economía , Pautas de la Práctica en Medicina/economía , Pautas de la Práctica en Medicina/estadística & datos numéricos , Práctica Privada/estadística & datos numéricos , Estados UnidosAsunto(s)
Contratos/ética , Competencia Económica/ética , Ética Médica , Práctica de Grupo/economía , Práctica de Grupo/ética , Médicos , Administración de la Práctica Médica/economía , Administración de la Práctica Médica/ética , Contratos/legislación & jurisprudencia , Competencia Económica/legislación & jurisprudencia , Práctica de Grupo/legislación & jurisprudencia , Humanos , Administración de la Práctica Médica/legislación & jurisprudencia , Estados UnidosRESUMEN
BACKGROUND: Development of new therapeutic modalities for human prostate carcinoma has been impeded by a lack of adequate in vitro and in vivo models. Most in vitro studies have been carried out using a limited number of human prostate cancer cell lines that are mostly derived from metastatic tumors sites or are immortalized. METHODS: Characterization of the prostate cancer cell line, HH870, included description of morphology, determination of doubling time, response to androgens, immunocytochemistry, and immunoblotting of proteins known to be associated with prostate carcinoma, karyotyping, fluorescence in situ hybridization (FISH), DNA profiling, and growth as xenograft in athymic rodents. RESULTS: HH870 expresses various epithelial marker antigens that correlate with known basic immunostaining profiles of prostate adenocarcinoma, although the cell line does not express PSA, PSMA, or PAP. HH870 exhibits complex chromosomal abnormalities and harbors no immortalizing HPV, BKV, JCV, and SV40 DNA. CONCLUSIONS: We report the successful establishment and characterization of a new long-term primary human prostate tumor cell line HH870.
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Técnicas de Cultivo de Célula/métodos , Línea Celular Tumoral/citología , Neoplasias de la Próstata/patología , Andrógenos/metabolismo , Animales , División Celular , Línea Celular Tumoral/trasplante , Aberraciones Cromosómicas , Humanos , Inmunohistoquímica , Hibridación Fluorescente in Situ , Masculino , Ratones , Ratones Desnudos , Trasplante de NeoplasiasRESUMEN
Benign prostatic hyperplasia is a common cause of urinary flow obstruction in aging men and may lead to lower urinary tract symptoms (LUTS). Benign prostatic hyperplasia has 2 physiological components: a static component related to increased prostate size and a dynamic component related to increased prostate smooth muscle tone. alpha1-Adrenoceptors (alpha1ARs) maintain prostate smooth muscle tone; hence, alpha1-antagonists (blockers) relax prostate smooth muscle and decrease urethral resistance, ultimately leading to relief of LUTS. This review focuses on alpha1AR subtypes and their location in lower urinary tract tissues involved in LUTS (prostate, bladder, spinal cord); it also summarizes major clinical trials published to date on the efficacy of alpha1AR blockers for LUTS. Benefits and adverse effects of clinically available alpha1AR antagonists are reviewed, followed by recent information on interactions between alpha1AR subtype antagonists and type 5 phosphodiesterase inhibitors used for impotence. alpha1-Adrenoceptor antagonists have become the mainstay of therapy for LUTS; knowledge about specific alpha1AR subtypes should facilitate rational choice of alpha1AR blocker therapy by clinicians.
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Antagonistas Adrenérgicos alfa/farmacología , Hiperplasia Prostática/tratamiento farmacológico , Hiperplasia Prostática/fisiopatología , Receptores Adrenérgicos alfa 1/fisiología , Humanos , Masculino , Receptores Adrenérgicos alfa 1/clasificación , Receptores Adrenérgicos alfa 1/metabolismo , Distribución TisularRESUMEN
PURPOSE: The most effective therapy for metastatic prostate cancer is androgen deprivation. Genes activated directly or possibly even indirectly by this steroid hormone represent potential targets for anticancer therapy. One such gene may be hTERT, which encodes the catalytic subunit of telomerase. In prostate cancer cells telomerase is activated, permitting sustained proliferation. Therefore, we tested whether hTERT gene expression is modulated in prostate cancer cells in vitro and in vivo by androgens. MATERIALS AND METHODS: Transcriptional activation of hTERT during androgen stimulation was assayed by luciferase assays using the hTERT promoter fused to the luciferase gene and by reverse transcriptase-polymerase chain reaction to detect endogenous hTERT mRNA in LNCaP cells. hTERT mRNA levels and telomerase activity were also measured in CWR22 prostate cancer cells implanted in mice that were subsequently castrated and left untreated or administered androgen. RESULTS: We report that the endogenous hTERT promoter is activated during the administration of androgen to androgen sensitive LNCaP prostate cancer cells. However, this effect was indirect since an hTERT promoter construct was not activated by androgens and transcription of the endogenous gene was not stimulated early enough in cultured cells to be considered a direct target of this steroid hormone. Importantly in an in vivo model of human prostate cancer androgen deprivation led to a decrease in hTERT expression, followed by a decrease in telomerase activity, which was reversed by a single administration of androgen. CONCLUSIONS: The hTERT gene is regulated in human prostate cancer cells in vivo by androgens.
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Andrógenos/fisiología , Regulación Neoplásica de la Expresión Génica , Neoplasias de la Próstata/metabolismo , Telomerasa/metabolismo , Andrógenos/farmacología , Animales , Proteínas de Unión al ADN , Genes Reporteros , Células HeLa , Humanos , Técnicas In Vitro , Luciferasas/genética , Masculino , Ratones , Ratones Desnudos , Trasplante de Neoplasias , Neoplasias Hormono-Dependientes/genética , Neoplasias Hormono-Dependientes/metabolismo , Orquiectomía , Regiones Promotoras Genéticas , Neoplasias de la Próstata/genética , ARN Mensajero/análisis , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Telomerasa/genética , Activación Transcripcional , Células Tumorales Cultivadas , Regulación hacia ArribaRESUMEN
PURPOSE: Positron emission tomography (PET) imaging is used for the metabolic evaluation of cancer. [18F]fluorodeoxyglucose (FDG) is commonly used as a radiotracer but its low cellular uptake rate in prostate cancer limits its usefulness. We evaluated the novel choline analog [18F]fluorocholine (FCH) for detecting androgen dependent and androgen independent prostate cancer, and its metastases. MATERIALS AND METHODS: The cellular uptake of FCH and FDG was compared in cultured prostate cancer cells (LNCaP and PC-3). FCH and FDG were injected into nude mice xenografts (CWR-22 and PC-3) and radiotracer uptake in various organs were evaluated. Patients with androgen dependent (9) and independent (9) prostate cancer were studied by FCH and FDG PET. RESULTS: FCH uptake was 849% and 60% greater than FDG uptake in androgen dependent (LNCaP) and independent (PC-3) cells, respectively. The addition of hemicholinium-3 (5 mM.) 30 minutes before radiotracer administration inhibited FCH uptake by 79% and 70% in LNCaP and PC-3 cells, respectively, whereas FDG uptake was not significantly affected. Although nude mice xenografts showed that FDG uptake was equal to or greater than FCH uptake, clinical imaging in patients demonstrated 2 to 4-fold higher uptake of FCH in those with androgen and androgen independent prostate carcinoma (p <0.001). More lesions were detected by FCH than by FDG in primary tumors, osseous metastases and soft tissue metastases. CONCLUSIONS: In vitro data demonstrated greater FCH than FDG uptake in androgen dependent (LNCaP) and androgen independent (PC-3) prostate cancer cells. Although the murine xenograft data showed greater accumulation of FDG than FCH in PC-3 tumors, PET in humans showed that FCH was better than FDG for detecting primary and metastatic prostate cancer. Overall the data from this study suggest that FCH is preferable to FDG for PET of prostate carcinoma and support the need for future validation studies in a larger number of subjects.
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Colina/análogos & derivados , Compuestos de Flúor , Radioisótopos de Flúor , Fluorodesoxiglucosa F18 , Neoplasias de la Próstata/diagnóstico por imagen , Radiofármacos , Tomografía Computarizada de Emisión , Animales , Colina/farmacocinética , Compuestos de Flúor/farmacocinética , Radioisótopos de Flúor/farmacocinética , Humanos , Masculino , Tasa de Depuración Metabólica/fisiología , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Trasplante de Neoplasias , Próstata/diagnóstico por imagen , Radiofármacos/farmacocinética , Sensibilidad y Especificidad , Distribución Tisular , Células Tumorales CultivadasRESUMEN
UNLABELLED: 18F-Fluorocholine (fluoromethyl-dimethyl-2-hydroxyethylammonium [FCH]) has been developed as an oncologic probe for PET. This study evaluates the kinetics and radiation dosimetry of 18F-FCH using murine and human biodistribution data. METHODS: The biodistribution of 18F-FCH was obtained at time points up to 10 h after administration in control and tumor-bearing anesthetized nude mice. Human biodistribution data within the first hour after injection were obtained from attenuation-corrected whole-body PET scans of male (n = 7) and female (n = 5) cancer patients. Radiation dosimetry estimates were calculated using the murine and human biodistribution data assuming no redistribution of tracer after 1 h. RESULTS: Rapid pharmacokinetics were observed for 18F-FCH in mice and humans. The biodistribution is nearly static after 10 min. The dose-critical organ is the kidney, which receives 0.17 +/- 0.05 and 0.16 +/- 0.07 mSv/MBq (0.64 +/- 0.18 and 0.55 +/- 0.32 rad/mCi) for females and males, respectively. The effective dose equivalent (whole body) from administration of 4.07 MBq/kg (0.110 mCi/kg) is approximately 0.01 Sv for females and males. CONCLUSION: 18F-FCH is rapidly cleared from the circulation and its biodistribution changes very slowly at >10 min after administration. The kidney is the dose-critical organ and limits administration levels of 18F-FCH to 4.07 MBq/kg (0.110 mCi/kg) in human research studies.