Georgetown University

About: Georgetown University is a education organization based out in Washington D.C., District of Columbia, United States. It is known for research contribution in the topics: Population & Cancer. The organization has 23377 authors who have published 43718 publications receiving 1748598 citations. The organization is also known as: GU & Georgetown.

Liver, gallbladder, extrahepatic bile ducts, and pancreas.

Abstract: Background. The liver, gallbladder, bile ducts, and pancreas have a common embryologic origin; cancers that arise from these sites therefore are expected to share a similar spectrum of histologic types. These cancers are known for their extremely poor prognoses. Methods. Data from the Surveillance, Epidemiology, and End Results Program regarding the incidence, distribution of histologic types, stage of disease, and survival for cancers of the gallbladder (n = 4412), extrahepatic bile ducts (n = 3486), pancreas (n = 23, 116), and liver (n = 6,391) were reviewed. The most common histologic types are discussed, and the frequency of rare types is reported. Results. The incidence of biliary cancer decreased, while the incidence of hepatic and pancreatic cancer rose slightly over the 15-year period from 1973 to 1987. Age and sex distributions varied by histologic type. Greater than 98% of pancreatic and biliary cancers were carcinomas, and adenocarcinoma (not otherwise specified) was the most common histologic type recorded. In the liver, hepatocellular carcinoma was the most common type, followed by intrahepatic cholangiocarcinoma. The overall 5-year relative survival rates for these cancers were very low: gallbladder, 12.3%; extrahepatic bile duct, 12.7%; liver 3.1%; and pancreas 2.5% (all stages combined, 1978-1986). Conclusions. This review confirmed that these carcinomas are associated with a very poor outcome; however, survival was influenced by stage of disease and histologic type. In the gallbladder and extrahepatic bile ducts, papillary adenocarcinoma was associated with the best outcome of all histologic types, and in the exocrine pancreas, mucinous cystadenocarcinoma was associated with the best prognosis.

Global expansion and redistribution of Aedes-borne virus transmission risk with climate change.

Abstract: Forecasting the impacts of climate change on Aedes-borne viruses—especially dengue, chikungunya, and Zika—is a key component of public health preparedness. We apply an empirically parameterized model of viral transmission by the vectors Aedes aegypti and Ae. albopictus, as a function of temperature, to predict cumulative monthly global transmission risk in current climates, and compare them with projected risk in 2050 and 2080 based on general circulation models (GCMs). Our results show that if mosquito range shifts track optimal temperature ranges for transmission (21.3–34.0°C for Ae. aegypti; 19.9–29.4°C for Ae. albopictus), we can expect poleward shifts in Aedes-borne virus distributions. However, the differing thermal niches of the two vectors produce different patterns of shifts under climate change. More severe climate change scenarios produce larger population exposures to transmission by Ae. aegypti, but not by Ae. albopictus in the most extreme cases. Climate-driven risk of transmission from both mosquitoes will increase substantially, even in the short term, for most of Europe. In contrast, significant reductions in climate suitability are expected for Ae. albopictus, most noticeably in southeast Asia and west Africa. Within the next century, nearly a billion people are threatened with new exposure to virus transmission by both Aedes spp. in the worst-case scenario. As major net losses in year-round transmission risk are predicted for Ae. albopictus, we project a global shift towards more seasonal risk across regions. Many other complicating factors (like mosquito range limits and viral evolution) exist, but overall our results indicate that while climate change will lead to increased net and new exposures to Aedes-borne viruses, the most extreme increases in Ae. albopictus transmission are predicted to occur at intermediate climate change scenarios.

Activation of estrogen receptor-alpha by the heavy metal cadmium.

Abstract: Previous studies from this laboratory have shown that the heavy metal cadmium (Cd) mimics the effects of estradiol in estrogen-responsive breast cancer cell lines. To understand the mechanism by which cadmium activates estrogen receptor-alpha (ER-alpha), the ability of cadmium to bind to and activate wild-type and various mutants of ER-alpha was examined. When tested in transient cotransfection assays in COS-1 cells, cadmium concentrations as low as 10(-11) M activated ER-alpha. Scatchard analysis employing either purified human recombinant ER-alpha or extracts from ER-containing MCF-7 cells demonstrated that l09Cd binds to the ER with an equilibrium dissociation constant of approximately 4 to 5 x 10(-10) M. Cadmium also blocks the binding of estradiol to ER-alpha in a noncompetitive manner (K(i) = 2.96 x 10(-10) M), suggesting that the heavy metal interacts with the hormone-binding domain of the receptor. To study the role of the hormone-binding domain in cadmium activation, COS-1 cells were transiently cotransfected with GAL-ER, a chimeric receptor containing the DNA-binding domain of the transcription factor GAL4 and the hormone-binding domain of ER-alpha, and a GAL4-responsive reporter gene. Treatment of the transfected cells with either 10(-6) M cadmium or 10(-9) M estradiol resulted in a 4-fold increase in reporter gene activity. The effect of cadmium on the chimeric receptor was blocked by the antiestrogen, ICI-164,384, suggesting that cadmium activates ER-alpha through an interaction with the hormone-binding domain of the receptor. Transfection and binding assays with ER-alpha mutants identified C381, C447, E523, H524, and D538 as possible interaction sites of cadmium with the hormone-binding domain of ER-alpha.

Credit scoring and the availability, price, and risk of small business credit

Abstract: We find that small business credit scoring (SBCS) is associated with expanded quantities, higher averages prices, and greater average risk levels for small business credits under $100,000, after controlling for bank size and other differences across banks. We also find that: (1) bank-specific and industry learning curves are important; (2) SBCS effects differ for banks that adhere to "rules" versus "discretion" in using the technology; and (3) SBCS effects differ for larger credits. The data do not support two alternative explanations of the main results under which the findings primarily represent statistical artifacts, rather than significant changes in lending behavior.

Electrosurgical apparatus employing constant voltage and methods of use

Abstract: Methods and apparatus are provided for use in performing electrosurgery, wherein a power supply supplies an electrosurgical instrument with a low voltage power signal having a substantially constant peak-to-peak voltage that is independent of the load impedance and which has a crest factor near unity. A power supply is provided to supply a voltage waveform in accordance with the methods of the invention. A clipping circuit is also provided to permit practice of the methods using conventional electrosurgcial generators and previously known electrosurgical instruments, wherein the voltage amplitude and waveform is modified to the desired regime.