Living 'gut-on-a-chip' to help study intestinal disorders

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The silicon polymer device, lined by living, human cells, mimics the 3D structures, behaviors, and environment of the human intestine.

Blue and red liquid is pumped through the device's upper and lower microchannels.

(Credit: Harvard)

After describing a living, breathing "lung-on-a-chip" in Science back in the summer of 2010, Harvard researchers are now reporting in the journal Lab on a Chip on their latest endeavor: a human gut-on-a-chip.

These bio-inspired micro devices that mimic the structures, behaviors, and environments of human organs could help scientists better understand the inner workings of a variety of diseases and disorders -- in this case intestinal ones such as Crohn's disease and ulcerative colitis -- without resorting to often less reliable animal testing.

The latest so-called "gut-on-a-chip" is a silicon polymer device whose central chamber is lined by a single layer of human intestinal epithelial cells that recreate the intestinal barrier by growing on a flexible and porous membrane. The device mimics the movement of food along the digestive tract as well as the flow of blood through capillaries.

The researchers report that they were even able to grow (and support) common intestinal microbes on the surfaces of the intestinal cells, mimicking various physiological features that could help understand diseases.

"Because the models most often available to us today do not recapitulate human disease, we can't fully understand the mechanisms behind many intestinal disorders," lead researcher Donald Ingber, a founding director of Harvard's Wyss Institute for Biologically Inspired Engineering, said in a news release. This means, he adds, "that the drugs and therapies we validate in animal models often fail to be effective when tested in humans."

In addition to being an in vitro diagnostic tool to help develop new therapeutics, Ingber's gut-on-a-chip might even be able to test the metabolism and oral absorption of drugs and nutrients.

The institute is also using DARPA funding awarded in 2011 to develop a spleen-on-a-chip to treat sepsis, a bloodstream infection that can be fatal.

See the team's video on their original lung-on-a-chip below:

Lung on a Chip -- Wyss Institute from Wyss Institute on Vimeo.

From advancements in electronic health records to cutting-edge surgical tools, CNET covers the medical-technology news buzzing through operating and waiting rooms.

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11:14 AM | 0 comments

MIT study: Light alone can activate specific memories

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Researchers say that using optogenetics to artificially reactivate memories could advance the study of neurodegenerative disorders.

A transgenic mouse hippocampus.

(Credit: Nikon Small World Gallery)

In a famous surgery in the early 1900s, Canadian neurosurgeon Wilder Penfield, trying to treat epilepsy, found that stimulating specific neurons while patients were under local anesthesia caused them to vividly recall complex events. The mind, then, is based on matter, Penfield concluded.

Now researchers at MIT say they put this observation to the test in a rigorous study showing that the direct reactivation of specific hippocampus neurons can lead to very specific memory recall. And to do this, all they used was light.

"We demonstrate that behavior based on high-level cognition, such as the expression of a specific memory, can be generated in a mammal by highly specific physical activation of a specific small subpopulation of brain cells -- in this case by light," Susumu Tonegawa, a biology and neuroscience professor at MIT, Nobel laureate and lead author of the study, said in a news release.

For the study, published online today in the journal Nature, researchers used optogenetics, a technique that combines optical and genetic methods to control specific events in specific cells. (The tech was co-invented by MIT's Ed Boyden, who last year proposed using optogenetics to induce light sensitivity in the retina and ultimately restore sight in the blind.)

Using optogenetics to stimulate memory, the researchers first learned which brain cells in the hippocampus were active in a mouse exploring a new environment. They then coupled the genes activated in those brain cells with the genes for channelrhodopsin-2 (ChR2), a light-activated protein used in optogenetics.

"We wanted to artificially activate a memory without the usual required sensory experience, which provides experimental evidence that even ephemeral phenomena, such as personal memories, reside in the physical machinery of the brain," said co-author Steve Ramirez, a graduate student in Tonegawa's lab.

The team then used tiny optical fibers to pulse light to neurons with this genetic couplet so that, by seeing the neurons associated with experiential learning light up, they could tag the physical network of neurons associated with a specific memory.

Their final step was to observe mice entering an environment, deliver a mild shock to their feet to teach the mice to fear the environment, tag the brain cells that were activated with ChR2, and then expose only those brain cells to pulses of light in a totally different environment. Sure enough, the mice assumed defensive, immobile crouches -- a sign that they were recalling the fear they experienced in the initial environment.

These findings are only preliminary, but the researchers believe that this light-induced fear demonstrates that the mice were remembering the shocks from a different time and place, and that light alone artificially re-activated that specific memory by stimulating the neurons they had tagged.

Tonegawa says their findings call into question Descartes' declaration that the mind is distinct from the body and cannot be studied as a natural science: "He was wrong. This experimental method is the ultimate way of demonstrating that mind, like memory recall, is based on changes in matter."

The researchers suggest that their method could advance the study of neurodegenerative and neuropsychiatric disorders. "The more we know about the moving pieces that make up our brains," said grad student Ramirez, "the better equipped we are to figure out what happens when brain pieces break down."

From advancements in electronic health records to cutting-edge surgical tools, CNET covers the medical-technology news buzzing through operating and waiting rooms.

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7:03 AM | 0 comments

Gaming can inspire healthy behavior, study shows

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I ricercatori di Stanford e HopeLab trovano che ri missione, un videogioco che coinvolge uccidere le cellule tumorali, attivano parti del cervello coinvolto nella motivazione.

Giallo/rosso/arancio mostra maggiore attività nel cervello di un partecipante al gioco ri missione, mentre spettacoli blu è diminuito di attività.

(Credito: screenshot da Elizabeth Armstrong Moore/CNET)

In re-mission il video gioco, i giocatori sono compiti di pilotare il microscopico robot Roxxi alle cellule tumorali lontano mentre lei Esplora i corpi dei pazienti affetti da cancro immaginario esplosione.

Un nuovo studio che ha preso tempo reale funzionale scansioni MRI di 57 persone assegnate casualmente a giocare il gioco o guardarlo in riproduzione ha trovato che coloro che hanno giocato esposte aumentata attività nei circuiti di motivazione positiva del cervello, mentre coloro che semplicemente osservato non esposto nessun aumento in attività.

"Identificando un collegamento diretto tra la stimolazione dei circuiti neurali e il gioco è una chiave passo nel liberare il potenziale per gli strumenti basati sui giochi ispirare il comportamento positivo e migliorare la salute," Brian Knutson, professore associato di psicologia e neuroscienze dell'Università di Stanford e co-autore di un articolo su nuovi dati, detto in un comunicato stampa ieri.

Knutson testato gli effetti di giocare ri missione con i ricercatori alla HopeLab, una fondazione senza scopo di lucro che si propone di sviluppare prodotti che influenzano positivamente i comportamenti di salute di quelli con l'aspettativa di cronica. I risultati appaiono questa settimana sulla rivista PLoS ONE.

Studio del gruppo si basa su ricerche precedenti, che indica che l'attivazione di questi circuiti ricompensa è direttamente connesso con una Spinta in aderenza ai trattamenti chemioterapici e antibiotico.

In questo studio, scansioni fMRI specificamente mostrarono che i circuiti implicati nella ricompensa (caudato, nucleo accumbens e putamen) erano attivi quando i partecipanti giocato ri missione, ma non quando essi passivamente osservato o erano a riposo. I ricercatori concludono che questi circuiti neurali mesolimbico sono attivati dalla effettiva per il gioco, non la stimolazione sensoriale che può verificarsi quando dire, guardare la TV.

Co-autore Steve Cole, vicepresidente di HopeLab di ricerca e sviluppo e un professore di medicina presso la University of California a Los Angeles, dice che hopelab consiste nell'applicare queste scoperte a lavorare ad una nuova generazione di ri missione di videogiochi per giovani malati di cancro.

La partita in corso re-mission è gratuite (donazioni opzionale) ma disponibile solo per Windows in formato CD o DVD.

Guarda un frammento video qui sotto:

Da progressi in cliniche elettroniche per strumenti chirurgici all'avanguardia, CNET copre le notizie di tecnologia medica ronzio attraverso operativo e sale d'attesa.

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11:25 PM | 0 comments

Latest study on the benefits of flaxseed

The use of these granules, or other supplements aid was a prophylactic treatment

High cholesterol in plasma is proven risk of cardiovascular disease. Deposits around the arteries is the causes of atherosclerosis, a precursor of stroke. New studies conducted with flaxseed suggest positive effects on the control of blood glucose and cholesterol, particularly LDL (bad). The results are most evident among people with a family history of cardiovascular disease or Dyslipidemia.

People whose blood cholesterol levels of 240 mg/dL reach doubles the risk of myocardial infarction compared to around 200 mg/dl. Warns the Spanish Foundation of the heart. After the medical diagnosis of hypercholesterolaemia, dietary therapy is the first choice for correcting the Dyslipidemia. They know that a number of foods which from their particular chemical composition, are required by the menu every day to make effective diet therapy: olive oil, avocado, nuts, fish, vegetables and fruits and vegetables.

The use of dietary supplements is a supplementary measure to reduce cholesterol levels. The most popular are soy lecithin, fish oil capsules and garlic preparations. Other new options are linseed, ginger and fig of India.

If in spite of following adequate food and the use of dietary supplements are not optimal results in reducing cholesterol, your doctor will discuss the need to use drugs. The effect will be more intense, fast and effective.

Cholesterol and flaxseed

The combination of fiber and omega 3 fatty acids in flaxseed confer protective properties against cardiovascular diseases

The use of flaxseed or other supplements to reduce cholesterol acts more like a prophylactic therapeutic aid. Can be a useful strategy to control cholesterol, especially among individuals with a family history of cardiovascular disease or Dyslipidemia. Recent references are available about the positive effects of flaxseed on blood glucose control and cholesterol, particularly LDL (bad).

Review the latest and most comprehensive is led by Memorial Sloan-Kettering Cancer Center in New York (USA). Were identified two bioactive compounds in seeds: soluble fiber (pectin and mucilage) and oil rich in unsaturated fatty acids (alpha-linolenic acid, a type of omega-3). The latter is more abundant in linseed oil. Alpha-linolenic acid is a direct precursor of the omega-3 fatty acids EPA and DHA. Several studies comparing the effects of cholesterol-lowering of fish oil. Omega-3 have a role in prevention of cardiovascular and anti-inflammatory effect.

The combination of nutritional factors, fiber and omega 3 fatty acids, explains that communicate with flax seeds for their protective properties against cardiovascular diseases. Despite these promising applications, the authors note that higher quality studies are needed to make any recommendation.

Seed, which, together, to land or oil?

Cell biology laboratory of St. Boniface Hospital Research Centre at the University of Manitoba in Canada, go a step further and investigate the bioavailability of alpha-linolenic acid from seeds and their physiological effects on the way in which they are taking the whole earth: or linseed oil. For this survey were prepared muffins with a full 30 grams of seeds or six grams of acid alpha-linolenic acid in oil. Effects on plasma levels of ALA (alpha-linolenic acid) have been measured participants in a month, two months and three months.

The researchers concluded that after ingestion of oil seeds and ground flaxseed, has achieved a significant increase in the levels of ALA (alpha-linolenic acid) in plasma, which was not true if you take the seeds whole. A result that surprised the authors is the failure to detect a significant increase in plasma levels of Eicosapentaenoic Acid (EPA) and Docosahexaenoic acid (DHA) in any of the participating groups, although the fatty acid that contains the seed is a precursor of the above.

In this period of time and dose included in the study has found no changes in plasma total cholesterol or triglycerides, but not analyzed for changes in the levels of LDL cholesterol. A negative aspect common to all groups was the onset of gastrointestinal disorders during the early stages of the study. These complaints disappeared after four weeks in the group taking the ground seeds or form of oil, but had reasons for the withdrawal of some individuals taking whole flax seed.

BREAD WITH SEEDS

The bread is added during processing rubber flaxseed can be a healthy alternative. One study evaluated the effect of flaxseed gum, glucose and low density cholesterol (LDL), through the work of Canadian experts in the Department of chemistry and biology (Ryerson University, Ontario) and Indian researchers from the school of medical sciences and technology, Indian Institute of Technology (Kharagpur) and the Department of biotechnology and Medical Engineering, National Institute of Technology (Rourkela).

Flaxseed gum consists of mucilage, a seed of flax fiber soluble (with shell) and a rubber-like texture. The technological properties of flaxseed gum linked to its high capacity thickening, swelling, which favors the ligation, emulsion. In this case, flaxseed gum was incorporated in wheat flour used to make Chapati, a type of traditional bread of India.

A total of 60 patients with type 2 diabetes for three months followed a diet that included the daily consumption of six chapati with a total of 5 grams of flaxseed gum. The control group also composed of 60 people ate a diet that is identical, but had no linen chapati. The values were taken biochemistry before beginning the study and at monthly intervals. The results showed a decrease in total cholesterol and LDL cholesterol. Also improved the profile of fasting plasma glucose in experimental group.

source

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9:23 AM | 0 comments