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Tuesday, August 25, 2015

New blood test for colon cancer improves colonoscopy screening results

THE OPTICAL SOCIETY

Optical Raman Spectra of Blood Shows Simple Fingerprint for Cancerous Growth and Precancerous Polyps 
August 24th, 2015
  

IMAGE: A NOVEL TEST SHOWS A DIFFERENCE IN THE RAMAN SPECTRA OF THE BLOOD PLASMA OF PEOPLE WITHOUT COLON CANCER COMPARED TO THOSE WITH PRECANCEROUS OR CANCEROUS POLYPS. view more

CREDIT: HAISHAN ZENG, BC CANCER AGENCY

WASHINGTON -- Canadian researchers have found a way to screen blood samples for molecular traces that indicate the presence of precancerous polyps in the colon, a key warning sign for colon cancer. Their results, published this week in the journal Biomedical Optics Express, from The Optical Society (OSA), may yield a cheaper and less invasive initial screening test for colon cancer that could complement colonoscopy, though further clinical trials will need to demonstrate the safety and effectiveness of the blood test before it is routinely used.

"This is a screening technology you can use on anybody," said Haishan Zeng, BC Cancer Agency, who led the study.


Thanks in part to screening technologies like colonoscopy; colon cancer is often detected in its earliest stages. By snaking a camera through a patient's intestines, doctors can identify polyps and other abnormal growths that could eventually become cancerous then remove them before they do. Many lives are saved each year because of this sort of routine screening.

The procedure can also be expensive and unpleasant. Patients must drink large quantities of laxatives the night before and undergo sedation or anesthesia during the exam itself. Current health guidelines say that adults should have a colonoscopy every ten years beginning at age 50 -- and sooner or more frequently if other risk factors exist -- but U.S. Centers for Disease Control and Prevention (CDC) statistics say that only 65 percent of American adults actually follow these guidelines.

That's why many researchers are searching for less invasive alternatives to the colonoscopy that could induce encourage more people to get tested.

In a step towards this goal, researchers from the BC Cancer Agency and the University of British Columbia have identified differences in the blood of people with precancerous polyps compared to people without such polyps. Their results could eventually lead to a cheaper and less invasive initial screening test for colon cancer.

The team collected blood plasma samples from three groups of people: 23 who had adenomatous (precancerous) polyps, 21 who had verified colon cancer, and 25 healthy volunteers. They mixed each plasma sample with silver nanoparticles and then analyzed the mixtures with surface-enhanced Raman spectroscopy (SERS). Raman spectroscopy uses a laser to excite the sample and measure shifts in the vibrational energy of its molecules, which can provide insight into the sample's molecular structure. In surface-enhanced Raman spectroscopy, nanoparticles are added to boost the signal.

In previous work, the team's collaborators at Fujian Normal University showed a difference in the Raman spectra of the blood plasma of people with colon cancer compared to individuals who were cancer-free. This new study demonstrated that the test can also be used to identify people with precancerous polyps -- a finding that makes it potentially more useful for a screening test, since it may be able to identify cancer risk before the disease actually develops.

A blood test that could detect precancerous polyps would be an improvement over other non-invasive colon cancer screening mechanisms currently available. For instance, the fecal occult blood test is an at-home kit that looks for evidence of microscopic traces of blood in stool samples, a potential sign of cancer. However, many early-stage colon cancers are asymptomatic and don't bleed, leaving them undetectable by this measure.

The initial results are promising, but the procedure is still in the research phase and must go through additional lab tests and clinical trials before actually being implemented. For instance, although the team identified significant spectral differences between the blood samples, they haven't yet determined the exact biomolecular sources for these differences. "We are planning new research to identify these responsible molecules," said Zeng.

A blood test for colon cancer will never replace colonoscopy: once polyps are identified, a colonoscopy is still the best way to figure out where they're located so that they can be removed. However, a blood test could be used as a first line of defense to identify patients with warning signs of cancer; these high-risk patients could then be referred for a colonoscopy to learn more.

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Paper: S. Feng, W. Wang, I. Tai, R. Chen, H. Zeng. "Label-free surface-enhanced Raman spectroscopy for detection of colorectal cancer and precursor lesions using blood plasma," Biomedical Optics Express 6, 3494-3502 (2015).

About Biomedical Optics Express

Biomedical Optics Express is OSA's principal outlet for serving the biomedical optics community with rapid, open-access, peer-reviewed papers related to optics, photonics and imaging in the life sciences. The journal scope encompasses theoretical modeling and simulations, technology development, and biomedical studies and clinical applications. It is published by The Optical Society and edited by Joseph A. Izatt of Duke University. Biomedical Optics Express is an open-access journal and is available at no cost to readers online at: OSA Publishing.

About The Optical Society


Founded in 1916, The Optical Society (OSA) is the leading professional organization for scientists, engineers, students and entrepreneurs who fuel discoveries, shape real-life applications and accelerate achievements in the science of light. Through world-renowned publications, meetings and membership initiatives, OSA provides quality research, inspired interactions and dedicated resources for its extensive global network of optics and photonics experts. OSA is a founding partner of the National Photonics Initiative and the 2015 International Year of Light. For more information, visit: http://www.osa.org.

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MUFON

How to Digitally Record/Video a UFO sighting:


Como registar digitalmente ou gravar um vídeo de um avistamento de um UFO:




Stabilize the camera on a tripod. If there is no tripod, then set it on top of a stable, flat surface. If that is not possible lean against a wall to stabilize your body and prevent the camera from filming in a shaky, unsteady manner.

Estabilize a camera com um tripé. Se não tiver um tripé, então coloque-a em cima de uma superfície estável. Se não for possível, então encoste-se a uma parede para estabilizar o corpo e evitar que a camera registe de maneira tremida e instável.

Provide visual reference points for comparison. This includes the horizon, treetops, lampposts, houses, and geographical landmarks (i.e., Horsetooth Reservoir, Mt. Adams, etc.) Provide this in the video whenever is appropriate and doesn’t detract from what your focus is, the UFO.

Forneça pontos visuais de referência para comparação. Isso inclui o horizonte, cimo das árvores, postes de iluminação, pontos de referência geográficos (como o Reservatório de Horsetooth, Mone Adams, etc) Forneça esses pontos no vídeo sempre que for apropriado e não se distraia do que é o seu foco, o UFO/a Nave.

Narrate your videotape. Provide details of the date, time, location, and direction (N,S,E,W) you are looking in. Provide your observations on the weather, including approximate temperature, windspeed, any visible cloud cover or noticeable weather anomalies or events. Narrate on the shape, size, color, movements, approximate altitude of the UFO, etc and what it appears to be doing. Also include any unusual physical, psychological or emotional sensations you might have. Narrate any visual reference points on camera so they correlate with what the viewer will see, and thereby will be better able to understand.

Faça a narração do vídeo. Forneça pormenores sobre a data, hora, local e direcção (Norte, Sul, Este, Oeste) que está a observar. Faça observações sobre as condições atmosféricas, incluindo a temperatura aproximada, velocidade do vento, quantidade de nuvens, anomalias ou acontecimentos meteorológicos evidentes. Descreva a forma, o tamanho, a cor, os movimentos, a altitude aproximada onde se encontra o UFO/nave, etc e o que aparenta estar a fazer. Inclua também quaisquer aspectos pouco habituais de sensações físicas, psicológicas ou emocionais que possa ter. Faça a narração de todos os pontos de referência visual que o espectador irá ver e que, deste modo, será capaz de compreender melhor.

Be persistent and consistent. Return to the scene to videotape and record at this same location. If you have been successful once, the UFO sightings may be occurring in this region regularly, perhaps for specific reasons unknown, and you may be successful again. You may also wish to return to the same location at a different time of day (daylight hours) for better orientation and reference. Film just a minute or two under “normal” circumstances for comparison. Write down what you remember immediately after. As soon as you are done recording the experience/event, immediately write down your impressions, memories, thoughts, emotions, etc. so it is on the record in writing. If there were other witnesses, have them independently record their own impressions, thoughts, etc. Include in this exercise any drawings, sketches, or diagrams. Make sure you date and sign your documentation.

Seja persistente e não contraditório. Volte ao local da cena e registe o mesmo local. Se foi bem sucedido uma vez, pode ser que nessa região ocorram avistamentos de UFOs/naves com regularidade, talvez por razões específicas desconhecidas, e talvez possa ser novamente bem sucedido. Pode também desejar voltar ao mesmo lugar a horas diferentes do dia (durante as horas de luz)para ter uma orientação e referência melhor. Filme apenas um ,inuto ou dois em circunstâncias “normais” para ter um termo de comparação. Escreva tudo o que viu imediatamente após o acontecimento. Logo após ter feito o registo da experiência/acontecimento, escreva imediatamente as impressões, memórias, pensamentos, emoções, etc para que fiquem registadas por escrito. Se houver outras testemunhas, peça-lhes para registar independentemente as suas próprias impressões, pensamentos, etc. Inclua quaisquer desenhos, esbolos, diagramas. Certifique-se que data e assina o seu documento/testemunho.

Always be prepared. Have a digital camera or better yet a video camera with you, charged and ready to go, at all times. Make sure you know how to use your camera (and your cell phone video/photo camera) quickly and properly. These events can occur suddenly, unexpectedly, and often quite randomly, so you will need to be prepared.

Esteja sempre preparado, Tenha sempre uma camera digital, melhor ainda, uma camera vídeo consigo, carregada e pronta a usar sempre que necessário. Certifique-se que sabe como lidar com a sua camera (ou com o seu celular/camera fotográfica) rápida e adequadamente. Esses acontecimentos podem acontecer súbita e inesperadamente e, por vezes, acidentalmente, por isso, necessita estar preparado.

Look up. Be prepared. Report. Share.

Olhe para cima, Esteja preparado, Relate, Partilhe.

MUFON.COM

ESOTERIC



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