Tuesday, August 4, 2009

Reconstructing Rome

I found this site yesterday and wanted to pass it along since it's so cool! A group from the University of Washington's Computer & Science Engineering Department is generating 3D reconstruction images of famous landmarks and cities using all the on-line images associated with a given landmark posted on Flickr.com. You can read more about the details of how they did this and see the reconstruction videos here: http://grail.cs.washington.edu/rome/

I wonder if my own picture taken above of the Trevi fountain (which is also posted on Flickr) was one of the 1,936 pictures used in their reconstruction...

Wednesday, July 22, 2009

You're Glowing

image by Kobayashi et al.

A recent observation by Japanese scientists gives new meaning to the words "you're glowing". Along with fireflies and jellyfish, humans emit small quantities of light, about 1000 times lower than what our eyes can detect. Place a human in front of a super-sensitive photon-detecting camera in the dark, however, and watch him glow! When imaging five healthy males for 20 minute intervals every 3 hours, researchers determined that the levels of "glowing" fluctuated throughout the day, peaking by 4 PM. The face exhibited the most amount of glow. The cause of glowing is likely due to the byproduct of chemical reactions taking place in our bodies involving free radicals, with glow fluctuations reflecting changes in our metabolism during the day.

Reference: Kobayashi M, Kikuchi D, Okamura H. (2009) Imaging of ultraweak spontaneous photon emission from human body displaying diurnal rhythm. PLoS ONE 4(7): e6256.doi:10.1371/journal.pone.0006256

Wednesday, July 8, 2009

Aloe Vera- Not Only for Cuts and Sunburns

photo by randomidea

A friend of mine was telling me about an article he read recently describing the health benefits of drinking aloe vera juice, particularly in aiding digestive issues. When we think of aloe vera, we usually think about using it to treat minor cuts, scrapes and burns- not cleansing our colons. Drinking aloe vera juice regularly helps repair damaged gut tissues and gently breaks down and washes out unabsorbed food particles in our colons. As an anti-inflammatory agent, aloe vera soothes digestive tract irritations, ulcers, colitis and acid reflux. It also encourages the release of pepsin, a gastric enzyme which degrades food proteins into amino acids. Although the initial phase of drinking aloe vera juice may cause diarrhea or stomach cramps during the "cleansing process" as toxins and build-up are removed, symptoms typically go away within a few days followed by increased intestinal function and relief from whatever was troubling you to begin with. So if you are suffering from irritable bowel symptom (IBS), heartburn, constipation, ulcers, or any other digestive issue, it's worth trying out aloe vera juice!

Monday, June 15, 2009

Swine Flu Vaccine on the Way

With the swine flu now declared a pandemic, several drug companies are actively working toward developing a vaccine. Last week, GlaxoSmithKline stated that it will soon begin large-scale vaccine production; Sanofi-Aventis is also developing one and Novartis has an experimental vaccine already, but it has not been tested in humans.

The WHO estimates that 2.4 billion doses of swine flu vaccine should be available in about 1 year. The challenge will be making sure the vaccine is evenly distributed throughout the world. Currently, the aim is to provide 10% of the global vaccine supply to poor and developing countries- this is especially important since individuals with preexisting health conditions (prevalent in developing countries) will be more susceptible to swine flu. Whether this will actually happen is up for debate since in past pandemics, most vaccines have remained in the countries where they were developed.

Source: Maria Cheng, "Drugmakers rush to produce a swine flu vaccine", The Associated Press, June 12, 2009.

Friday, June 12, 2009

Swine Flu Pandemic Has Started

photo by Eneas

The swine flu has now been declared a pandemic by World Health Organization (WHO) officials. A pandemic is any epidemic or infection that spreads through a large population ("pan" = all, "demos" = people). This is the first flu pandemic since the Hong Kong flu pandemic of 1968 , when an estimated 1 million people died worldwide. Although the swine flu virus is rapidly spreading, it doesn't mean that the virus itself is more lethal or virulent; it's actually not much more severe than the seasonal flu, but the main difference is that since previous exposure to the virus has not occurred, we have little to no preexisting immunity to the virus and no vaccines to effectively combat infection. The pandemic declaration, however, will definitely speed the production of a swine flu vaccine.

Friday, June 5, 2009

Bacteria- They've Got You Covered

photo by IRRI Images

Bacteria literally have us covered, inside and out. NIH researchers have found that the healthy human epidermis is home to about 1000 species of bacteria, or an estimated 100 billion individual bacteria total. Various regions of skin from 10 volunteers (5 female, 5 male) were swabbed to collect bacterial samples for analysis. The study found that moist areas housed 10 times more bacteria than dry areas. The human forearm alone showed the greatest bacterial diversity with 44 species detected, while the oily area behind the ear had only 15 species. Interestingly, similar species were found in the same areas on each individual, indicating that bacterial species have their own niche on our skin as well as pointing to a mutualistic relationship between "us" and "them".

Source: Karen Kaplan, "1000 Species of Bacteria Found on Healthy Humans", Los Angeles Times, May 29, 2009.

Thursday, May 21, 2009

What's H1N1, Anyway?

The recent swine flu virus has been characterized as “H1N1” and if you remember a few years ago, the bird flu was caused by an “H5N1” virus. So what do the H and N mean, and why the different numbers? All influenza viruses have the proteins hemagglutinin (H) and neuraminidase (N) on their surfaces, or outer coating. Hemagglutinin is involved in virus binding to host cells, aiding in the initial step of virus entry into the cells it infects. Once a virus gains access to a cell, it uses the host cell’s machinery to replicate itself, leading to the production of more infectious viruses. Newly replicated viruses need to be released from the host cell so they can continue with more rounds of infection, so neuraminidase acts as an enzyme which helps in this release process. In fact, neuraminidase inhibitors, such as Relenza and Tamiflu, are often used to treat flu.

The protein structure of both H and N differ from one influenza virus strain to another, so the numbering system corresponds to the form or version of the protein on a given virus. In humans, three H and two N subtypes are found, indicating that the swine flu virus carries subtype 1 of the H protein and subtype 1 of the N protein on its surface. By determining the subtypes of H and N on a given virus, we can anticipate its virulence and potential impact by comparing it to viruses we have seen in the past with the same or similar protein makeup.

Tuesday, May 12, 2009

Cover Your Mouth

photo by markhillary

With so much hype about the swine flu, it's time to start sneezing and learn a little bit more about infections!
SNEEZE- Start Infecting

Tuesday, April 28, 2009

Muscular Dystrophy and Eye Defects

photo by Look Into My Eyes

Facioscapulohumeral muscular dystrophy (FSHD) is a degenerative disease causing the weakening of muscles in the face, shoulders, and upper arms. The disease usually manifests itself by the age of 20 and progresses slowly, with occasional stages of rapid deterioration. As an autosomal dominant disorder, FSHD is caused by a DNA deletion in chromosome 4. In addition to the weakening of muscles, many with the disorder experience vision problems due to abnormal blood vessel formation in the eyes.

About 95% of those affected show a defect in the expression of FRG1, a gene which aids in skeletal muscle development in frogs as well as humans. Researchers at the University of Illinois decided to determine if the FRG1 gene was also responsible for the defective angiogenesis in the eye of FSHD patients. They determined that the FRG1 gene product was highly expressed in the blood vessels of frogs and is important for proper vessel growth and organization. Thus the lack of this gene would account for abnormalities seen in the eye of humans, which was further shown by the study. Aberrant FRG1 expression therefore leads to defective skeletal muscle development and angiogenesis of the eye, both hallmarks of FSHD.

Source: Science Daily- Researchers Identify Gene Associated With Muscular Dystrophy-related Vision Problems

Wednesday, April 22, 2009

Walnuts and Breast Cancer

photo by SusanneK

The health benefit of eating nuts regularly is known by most- nuts contain protein, healthy fats, antioxidants and vitamins. A study from the Marshall University School of Medicine now shows that consuming walnuts, which are high in omega-3 fatty acids, phytosterols and flavonoids, may help to prevent breast cancer. The study was done using a strain of mice that normally develops breast cancer. Mice were put on either a standard diet or fed the human equivalent of 2 ounces of walnuts each day. The walnut-fed mice developed fewer tumors; when tumors did arise, they took longer to develop and were much smaller compared to tumors in non-walnut fed mice. Although these studies were performed in mice, it is likely that similar cancer prevention benefits would be seen in humans. Previous reports have also linked nuts with lowered risk of coronary heart disease in women. In addition to walnuts, other foods high in omega-3 fatty acids include fish (particularly salmon), flaxseeds and green vegetables.

Sources: BBC News- “Walnuts May Prevent Breast Cancer”
Science Daily- “Walnuts May Prevent Breast Cancer”

Tuesday, April 21, 2009

Intradermal Vaccinations

photo by NathanF

The thought of shots and needles makes many people cringe and in some cases avoid getting important vaccinations. Most vaccines are administered intramuscularly, as this optimizes the immunogenicity of the vaccine and minimizes adverse reactions at the site of injection. Researchers have recently studied the efficiency of intradermal (ID) vaccination compared to intramuscular (IM) vaccination against seasonal influenza. The ID method uses a narrow 1.5 mm needle which is inserted perpendicularly into the skin, delivering the drug into the upper layers of the skin rather than into deeper tissues beneath the skin or muscle. Since skin acts as an immunological barrier and is home to professional antigen-presenting cells such as dermal dendritic cells (see March 18, 2009 post) and Langerhans cells, ID vaccination delivers antigen directly to immune cells.

By testing different amounts of the vaccine delivered either ID or IM, a dose was determined where ID vaccination was statistically non-inferior to IM vaccination and showed comparable immunogenic and safety profiles. Although ID injection resulted in increased local inflammation and redness, this study validates the use of ID vaccination and may prove to be a good alternative for those who dislike IM injections.

Reference: Beran J, Ambrozaitis A, Laiskonis A, Mickuviene N, Bacart P, Calozet Y, Demanet E, Heijmans S, Van Belle P, Weber F, Salamand C. (2009) Intradermal influenza vaccination of healthy adults using a new microinjection system: a 3-year randomised controlled safety and immunogenicity trial. BMC Medicine 7(1):13.

Thursday, April 16, 2009

Magnetic Stem Cells

photo by JonathanPalero

Self-renewal and potency: the beauty of stem cells. Researchers at Keele University have now developed a clever method of delivering stem cells to a desired destination through the use of magnets. In the study, stem cells coated with magnetic particles were injected into mice and magnetically maneuvered to where they were needed, leading to the growth of new bone. The team estimates that the technique could be tested in humans within 5 years and used to treat injuries, fractures, and arthritis. In this case, a patient’s own stem cells would be harvested from their bone marrow and coated with magnetic particles. The magnetized cells would then be re-injected into the body where magnets would be used to properly position them.

Source: BBC News- “Bone-repairing stem cell jab hope”

Friday, April 10, 2009

Eat Your Curry Powder

photo by madpai

Curry powder may be doing more than flavoring your food! Turmeric, a spice found in curry powder, has been shown to have many health benefits. These benefits arise from curcumin, the main component of turmeric which gives the spice its rich yellow-orange color. In addition to having antioxidant properties, curcumin exhibits anti-inflammatory and immunomodulatory effects, all of which are important in disease progression. Several reports now show that curcumin has the potential to fight against Alzheimer’s disease, cancer, multiple sclerosis, diabetes, psoriasis, and cardiovascular diseases. In the case of Alzheimer’s, curcumin inhibits/slows the accumulation of amyloid plaques (dense deposits of beta-amyloid protein) in the brain of mice. Some suggest this may explain in part the low rate of Alzheimer’s disease in India, a population with prevalent use of curry powder and related spices.

Reference: Jagetia, GC and Aggarwal, BB (2007) “Spicing up” of the immune system by curcumin. Journal of Clinical Immunology 27(1): 19-35.

"Curry Spice May Fight Against Alzheimer's Disease"

Tuesday, April 7, 2009

Red in the Face

photo by nyki_m

What do you find attractive? Rosy red cheeks, perhaps? In humans, red coloration of the skin is usually viewed as a sign of physiological health and attractiveness. The same is true for several bird species and non-human primates; animals often use red coloration as signals for health, social status, hormonal conditions or attracting mates. Researchers at the University of St Andrews in Scotland hypothesized that increased skin blood perfusion would be perceived as healthy and that oxygenated blood color (bright red) of the face would appear healthier than deoxygenated blood color (bluish-red). To test this theory, individuals were shown facial images on a monitor, where color could be adjusted, and asked to change the coloring of the faces until they appeared as healthy as possible. The adjustments in color corresponded to an increase or decrease in facial blood perfusion and oxygen.

The hypothesis proved to be true- blood coloration of facial images was increased, suggesting skin coloration is viewed as a cue to underlying health. Interestingly, when comparing female and male faces, more oxygenated blood color was added to female faces. So how can you get that rosy glow? For women, the formation and widening of blood vessels results in an increase in skin blood color, processes intensified naturally by female hormones and exercise.

Reference: Stephen ID, Coetzee V, Law Smith M, Perrett DI (2009) Skin Blood Perfusion and Oxygenation Colour Affect Perceived Human Health. PLoS ONE 4(4): e5083. doi:10.1371/journal.pone.0005083

Tuesday, March 31, 2009

How Hot is Your Tea?

photo by prakhar

Researchers at the University of Tehran have found a link between drinking steaming hot tea and an increased risk of esophageal cancer, as published in the British Medical Journal. The study looked at people living in the Golestan province of Iran, an area where individuals drink over a liter of tea a day. Esophageal cancer has several contributing factors, including heavy alcohol consumption, tobacco use, chronic acid reflux, diet and obesity. Although alcohol and tobacco are the main contributors in the US and Europe, these activities are not common in Golestan, yet this province has one of the highest rates of esophageal cancer in the world.

By studying the tea drinking habits of individuals with esophageal cancer compared with healthy participants in the region, it was determined that drinking tea at a temperature of 70C or higher increased the risk of esophageal cancer 8-fold compared to drinking tea at a temperature of 65C or less. So does this mean you should have a thermometer handy every time you want a soothing cup of tea? Not necessarily, but if anything, it is probably a good idea to avoid drinking scalding hot tea or liquids in general. Further investigations into how heat can lead to the development of cancer as well as the prevalence of medical conditions within the Golestan population that could lead to esophageal cancer susceptibility will continue to shed light on this interesting observation.

Sources: BBC News- Steaming Hot Tea Linked to Cancer;
NHS News- Hot Tea and Cancer

Tuesday, March 24, 2009

The Not So Sweet Smell of DEET

photo by rob lee

Those darn mosquitoes! If you’ve ever gone camping or hiking, you have most likely used N,N-Diethyl-meta-toluamide, commonly known as the insect repellent DEET. So how does DEET manage to keep pesky bugs away? In the case of mosquitoes, it appears that they smell DEET directly. The hair-like sensory organs found on the antennae and maxillary palps of mosquitoes house olfactory receptor neurons (ORN) which sense smell. With increasing concentrations of DEET, increased neuronal excitation occurs within the ORNs, indicating that the act of smelling is causing a reaction and the response is dose-dependent.

Mosquitoes not only smell DEET directly, they also avoid it. When Petri dishes were set containing either solvent or DEET-treated filter paper, mosquitoes landed in the solvent-only area significantly more. Likewise, when mosquitoes were given the option to fly towards sugar-treated cotton only after passing through an area where DEET vapors were being released, they avoided landing or departed shortly after landing. This further indicates that an interaction between mosquitoes with actual odorants is not necessary for DEET-induced repellency-- the mosquitoes are able to smell DEET and avoid it.

Reference: Syed Z and Leal WS. (2008) Mosquitoes smell and avoid the insect repellent DEET. PNAS. 105(36):13195-6.

Wednesday, March 18, 2009

Dendritic Cells to the Rescue

photo by burning image

Dendritic cells (DCs) are immune cells in the body which collect antigens in tissues, process the antigen, and then present the antigen to other immune cells, such as T cells, mounting an immune response. Put more simply, DCs are always on the look out for those bad guys that invade our bodies, like viruses. Once DCs capture these pathogens, they transport them to other cells which can fight against the invader.

Several types of DCs exist, including ones that lie in the dermis (layer of skin below the epidermis), termed “dermal dendritic cells” (DDCs). Upon visualizing the behavior of DDCs under normal conditions, they appear to be highly motile and actively crawl through spaces within the dermis. To see how DDCs would react upon introduction of a pathogen, researchers injected skin with the protozoan parasite Leishmania. This parasite is transmitted by sand flies which bite individuals, depositing the parasite into the dermis, causing cutaneous leishmaniasis. When DDCs encountered the parasite, their behavior and morphology changed rapidly- they became stationary and extended long, motile pseudopods capable of reaching out to and engulfing the pathogens. In fact, multiple parasites were incorporated into small compartments within the DDC. This shows how DDCs quickly respond to “danger signals”, allowing for the initiation of an immune response. So thank your DCs for slowing down every now and then and taking care of your unwelcome guests!

Reference: Ng LG, Hsu A, Mandell MA, Roediger B, Hoeller C, et al. (2008) Migratory dermal dendritic cells act as rapid sensors of protozoan parasites. PLoS Pathog 4(11): e1000222. doi:10.1371/ journal.ppat.100022 2

Monday, March 16, 2009

HIV: The Wolf in Sheep’s Clothing

photo by sarahheiman

"I can’t live if living is without you”…these may be words sung and spoken by many, but if a virus could speak, these are the exact words it would say to the cell it infects. Viruses, such as HIV, act like parasites and use the proteins and replication machinery present in the host cells they infect in order to propagate themselves. When viruses replicate and bud out of the cells they infect (T cells in the case of HIV), they take along some of the cell’s proteins and incorporate them into their own viral envelope. Uninfected T cells also normally release small particles called microvesicles which are involved in modulating immune responses. When such microvesicles bud out of T cells, they take with them proteins from the T cell plasma membrane.

A recent study has examined the carbohydrate composition of proteins coating the surface of HIV derived from infected T cells to that of microvesicles derived from uninfected T cells. The study shows that the carbohydrates present on virions were the same as those found on native microvesicles, indicating that HIV can cleverly camouflage itself within the host by covering itself with a “coat” that closely mimics immunomodulatory microvesicles.

Reference: Krishnamoorthy L, Bess JW Jr, Preston AB, Nagashima K, Mahal LK. (2009) HIV-1 and microvesicles from T cells share a common glycome, arguing for a common origin. Nature Chemical Biology 5(4):244-50.