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June 17, 2008

How Humans Evolved Allergies

Ancient antibody molecule offers clues to how humans evolved allergies

The chicken molecule, an antibody called IgY, looks remarkably similar to the human antibody IgE. IgE is known to be involved in allergic reactions and humans also have a counterpart antibody called IgG that helps to destroy invading viruses and bacteria. Scientists know that both IgE and IgG were present in mammals around 160 million years ago because the corresponding genes are found in the recently published platypus genome. However, in chickens there is no equivalent to IgG and so IgY performs both functions.

Lead researcher, Dr. Rosy Calvert said: “Although these antibodies all started from a common ancestor, for some reason humans have ended up with two rather specialised antibodies, whereas chickens only have one that has a much more general function.

Professor Brian Sutton, head of the laboratory where the work was done said: “It might be that there was a nasty bug or parasite around at the time that meant that humans needed a really dramatic immune response and so there was pressure to evolve a tight binding antibody like IgE. The problem is that now we’ve ended up with an antibody that can tend to be a little over enthusiastic and causes us problems with apparently innocuous substances like pollen and peanuts, which can cause life-threatening allergic conditions.”

Related: Parasitic Worms Reduce Hay Fever Symptoms - Understanding the Evolution of Human Beings by Country - Hypoallergenic Cats

April 24, 2008

Walking Without Shoes

You Walk Wrong

Last year, researchers at the University of the Witwatersrand in Johannesburg, South Africa, published a study titled “Shod Versus Unshod: The Emergence of Forefoot Pathology in Modern Humans?” in the podiatry journal The Foot. The study examined 180 modern humans from three different population groups (Sotho, Zulu, and European), comparing their feet to one another’s, as well as to the feet of 2,000-year-old skeletons. The researchers concluded that, prior to the invention of shoes, people had healthier feet. Among the modern subjects, the Zulu population, which often goes barefoot, had the healthiest feet while the Europeans - i.e., the habitual shoe-wearers - had the unhealthiest

My new Vivo Barefoots aren’t perfect - they’re more or less useless in rain or snow, and they make me look like I’m off to dance in The Nutcracker. But when I don’t wear them now, I kind of miss them. Not because they’re supposedly making my feet healthier, but because they truly make walking more fun. It’s like driving a stick shift after years at the wheel of an automatic - you suddenly feel in control of an intricate machine, rather than coasting on cruise control. Now I better understand what Walt Whitman meant when he wrote (and I hate to quote another Transcendentalist, but they were serious walking enthusiasts): “The press of my foot to the earth springs a hundred affections.”

Related: Ministry of Silly Walks - Treadmill Desks

April 13, 2008

Study challenges notion of ‘pandemic’ flu

Study challenges notion of ‘pandemic’ flu

Peter Doshi, a graduate student in the History, Anthropology, and Science, Technology and Society Program at MIT, based his study on an analysis of more than a century of influenza mortality data. He found that the peak monthly death rates in the 1957-1958 and 1968-1969 pandemic seasons were no higher than–and were sometimes exceeded by–those for severe nonpandemic seasons.

Doshi says the pandemic-equals-extreme-mortality concept appears to be a generalization of a single data point: the 1918 season, a period in which “doctors lacked intensive care units, respirators, antiviral agents and antibiotics.” He argues that “had no other aspect of modern medicine but antibiotics been available in 1918, there seems good reason to believe that the severity of this pandemic would have been far reduced.”

As may be expected given improvements in living conditions, nutrition and other public health measures, influenza death rates substantially declined across the 20th century. Doshi calculates an 18-fold decrease in influenza deaths between the 1940s and 1990s, a trend that began far before the introduction of widespread vaccination.

Related: Why the Flu Likes Winter - Reducing the Impact of a Flu Pandemic - Drug-resistant Flu Virus - Avian Flu

April 12, 2008

Eating Breakfast Keeps Teenagers Leaner

Breakfast ‘keeps teenagers lean’

In a five year study of more than 2,000 youngsters, those who skipped breakfast weighed on average 5lbs (2.3kg) more than those who ate first thing. This was despite the fact that the breakfast-eaters consumed more calories in the course of the day. But the study in Pediatrics found they were likely to be much more active.

The University of Minnesota research adds weight to a growing body of evidence that those who eat breakfast - whether young or old - are leaner than those who do not.

“The real problem is the profusion of messages about obesity. We need to make clear that eating regular meals is vital - and that a proper breakfast is very important. “If you eat well first thing, you’ll feel brighter, you’ll have more get up and go - and that will mean you’ll expend more energy.”

Teenagers are not the only ones who may benefit from sitting down to a proper breakfast. In a study of nearly 7,000 middle-aged people in Norfolk, a team from Cambridge University found that those who ate the most in the morning put on the least amount of weight.

Related: Breakfast Eating and Weight Change in a 5-Year Prospective Analysis of Adolescents: Project EAT (Eating Among Teens) - $500 Million to Reduce Childhood Obesity in USA - Eat food. Not too much. Mostly plants - Food Health Policy Blog

April 10, 2008

Self-assembling Nanofibers Heal Spinal Cords in Mice

Self-assembling Nanofibers Heal Spinal Cords by Prachi Patel-Predd

An engineered material that can be injected into damaged spinal cords could help prevent scars and encourage damaged nerve fibers to grow. The liquid material, developed by Northwestern University materials science professor Samuel Stupp, contains molecules that self-assemble into nanofibers, which act as a scaffold on which nerve fibers grow.

Stupp and his colleagues described in a recent paper in the Journal of Neuroscience that treatment with the material restores function to the hind legs of paralyzed mice.

The new work is the first test for the material to heal spinal cord injuries in animals. And Kessler says that it worked better than the researchers expected. The researchers stimulated a spinal cord injury in mice and injected the material 24 hours later. They found that the material reduced the size of scars and stimulated the growth of the nerve fibers through the scars. It promoted the growth of both types of nerve fibers that make up the spinal cord: motor fibers that carry signals from the brain to the limbs, and sensory fibers that carry sense signals to the brain. What is more, the material encouraged the nerve stem cells to mature into cells that create myelin–an insulating layer around nerve fibers that helps them to conduct signals more effectively.

Related: Using Bacteria to Carry Nanoparticles Into Cells - Micro-robots to ’swim’ Through Veins - Nanowired at Berkeley

April 8, 2008

Clay Versus MRSA Superbug

“Healing clays” hold promise in fight against MRSA superbug infections and disease

Scientists from Arizona State University report that minerals from clay promise could provide inexpensive, highly-effective antimicrobials to fight methicillin-resistant Staphylococcus aureus (MRSA) infections that are moving out of health care settings and into the community.

Unlike conventional antibiotics routinely administered by injection or pills, the so-called “healing clays” could be applied as rub-on creams or ointments to keep MRSA infections from spreading

In their latest study, funded by the National Institutes of Health, Williams, Haydel and their colleagues collected more than 20 different clay samples from around the world to investigate their antibacterial activities… The researchers identified at least two clays from the United States that kill or significantly reduce the growth of these bacteria

Also listen to a podcast with the researchers, Lynda Williams and Shelly Haydel, that provides much more detail. The Science Studio podcasts from Arizona State University provides great science podcasts.

Related: Soil Could Shed Light on Antibiotic Resistance - Entirely New Antibiotic Developed - Science Webcast Directory - NSF Awards $50 Million for Collaborative Plant Biology Project (University of Arizona)

April 1, 2008

Cancer Deaths Increasing, Death Rate Decreasing

Last year I questioned this quote “confirming” a declining trend of cancer deaths: “Cancer deaths in the United States dropped for the second year in a row, health officials reported yesterday, confirming that the trend is real and becoming more pronounced, too.” Well the data is in for the next year (2005) and cancer deaths increased - so much for the 2 year “trend.”

Despite a continuing decline in the cancer death rate from 2004 to 2005, there was an increase of 5,424 deaths (559,312 cancer deaths in 2005 compared to 553,888 cancer deaths in 2004). This increase follows a decrease in the number of cancer deaths in the two previous years.

The American Cancer Society provides much better wording this year, I believe:

“The increase in the number of cancer deaths in 2005 after two years of historic declines should not obscure the fact that cancer death rates continue to drop, reflecting the enormous progress that has been made against cancer during the past 15 years.” said John R. Seffrin, Ph.D., American Cancer Society chief executive officer. “While in 2005 the rate of decline was not enough to overtake other population factors, the fact remains that cancer mortality rates continue to drop, and they’re doing so at a rate fast enough that over a half million deaths from cancer were averted between 1990/1991 and 2004.”

Good news, and well stated. Related: Leading Causes of Death - Cancer Cure - Not so Fast

March 31, 2008

Don’t Eat What Doesn’t Rot

Here is a nice interview of Michael Pollan by Amy Goodman - Don’t Eat Anything That Doesn’t Rot:

Another assumption of nutritionism is that you can measure these nutrients and you know what they’re doing, that we know what cholesterol is and what it does in our body or what an antioxidant is. And that’s a dubious proposition.

if you look at the layout of the average supermarket, the fresh whole foods are always on the edge. So you get produce and meat and fish and dairy products. And those are the foods that, you know, your grandmother would recognize as foods. They haven’t changed that much. All the processed foods, the really bad stuff that is going to get you in trouble with all the refined grain and the additives and the high-fructose corn syrup, those are all in the middle. And so, if you stay out of the middle and get most of your food on the edges, you’re going to do a lot better.

Related: Research on Why Healthy Living Leads to Longer Life - Eat food. Not too much. Mostly plants. - Raised Without Antibiotics - Another Strike Against Soda - Energy Efficiency of Digestion

March 1, 2008

Placebo Effect

Don’t laugh, sugar pills are the future

In fact the new study added nothing (and it was ridiculously badly reported): we already knew that antidepressants perform only marginally better than placebo, and the National Institute for Health and Clinical Excellence (Nice) guidelines has actively advised against using them in milder depression since 2004. But the more interesting questions are around placebo.

Another study from 2002 looked at 75 trials of antidepressants over the past 20 years, but looked only at the response in the placebo arms of the trials, and found that the response to placebo has increased significantly in recent years (as has the response to medication): perhaps our expectations of those drugs have increased, or perhaps, conversely to our earlier example, the trial designs have become systematically more flattering. I’m giving you tenuous data, on an interesting area, because I know you’re adult enough to cope with ambiguity.

Related: Placebo Response in Studies of Major Depression - An Exploration of Neurotic Patients’ Responses to Placebo When Its Inert Content Is Disclosed - Discussing Medical Study Results - Why Most Published Research Findings Are False

February 12, 2008

Electrical Brain Stimulation Boosts Memory

Deep stimulation ‘boosts memory’

The technique involves implanting electrodes into the brain: in this case into an area in the limbic system called the hypothalamus, which is thought to control the appetite. When the electrodes were stimulated by electrical impulses the patient began to experience feelings of deja vu.

He then had a sudden perception of being in a park with friends. He felt younger, thought he was around 20-years-old, and his girlfriend of the time was there. He was an observer, and saw the scene in colour. As the intensity of the stimulation increased, details in the scene became more vivid.

The results suggest it might be possible to use deep brain stimulation directly to boost memory. “We hopefully have found a circuit in the brain which can be modulated by stimulation, and which might provide benefit to patients with memory disorders,” said Professor Lozano. He is now leading a pilot study into whether deep brain stimulation can help people with early Alzheimer’s disease. They are initially testing six patients.

Related: Oliver Sacks podcast - The Brain is Wired to Mull Over Decisions - How The Brain Rewires Itself - Deep brain stimulation could help memory loss

February 8, 2008

Surprising New Diabetes Data

Surprising New Diabetes Data

But these measures are only surrogates for disease. And in many cases, the connection between “better” numbers and better health is tenuous. In the case of cholesterol, many people won’t see a health benefit from lower numbers.

Now comes yet another sobering reminder that lowering a surrogate marker doesn’t necessarily bring better health. On Feb. 6, the National Institutes of Health announced it was halting a key trial for diabetes. Researchers had hoped the trial, dubbed ACCORD (Action to Control Cardiovascular Risk in Diabetes), would show that more aggressive lowering of blood sugar would significantly reduce deaths. Instead, the opposite happened. More people in the intensive treatment group died than in the group getting standard care. “A thorough review of the data shows that the medical treatment strategy of intensively reducing blood sugar below current clinical guidelines causes harm in these…patients,” says Dr. Elizabeth Nabel, director of the National Heart, Lung & Blood Institute.

Scientific study often results in less than clear conclusions, especially in complex systems. There is great difficulty understanding what is actually going on, what interactions are present, what factors are significant, etc.. One of the great problems with the low level of scientific literacy in the USA is so many people think science is about simple absolute truth.

Scientific inquiry, especially related to health care, must attempt to gain insights from confusing signals. To gain scientific literacy one must understand basics concepts, like data is a proxy for what you aim to understand. To understand yourself you need to accept that science is not math. For a long time we are going to have to do our best to build up our understanding of human health (and other complex systems) as best we can. We need to be able to sort out what are solid conclusion, what are guesses, what seem like reasonable explanation and what level of confidence we can have in statements.

It is not enough to learn facts we need to be able to think scientifically and comprehend the subtleties surrounding the advances in scientific understanding. Some criticize newspapers and popular science for providing too simplistic a view of new scientific knowledge. While this can be a problem I really see the problem much more serious if people read obviously overly simplistic articles and don’t understand that it is just scratching the surface. The reader needs to take responsibility too. I enjoy many great articles that gloss over many of the details but provide a quick view of intriguing new breakthroughs.

Related: New Questions on Treating Cholesterol - Evolution is Fundamental to Science - Contradictory Medical Studies - The Study of Bee Colony Collapses Continues - Antibiotics Too Often Prescribed for Sinus Woes

December 27, 2007

Brain Development

Making the Mind, Why we’ve misunderstood the nature-nuture debate by Gary Marcus

The mapping between genes and behavior is made even more complex by the fact that few if any neural circuits operate entirely autonomously. Except perhaps in the case of reflexes, most behaviors are the product of multiple interacting systems. In a complex animal like a mammal or a bird, virtually every action depends on a coming together of systems for perception, attention, motivation, and so forth. Whether or not a pigeon pecks a lever to get a pellet depends on whether it is hungry, whether it is tired, whether there is anything else more interesting around, and so forth. Furthermore, even within a single system, genes rarely participate directly “on-line,” in part because they are just too slow. Genes do seem to play an active, major role in “off-line” processing, such as consolidation of long-term memory—which can even happen during sleep—but when it comes to rapid on-line decision-making, genes, which work on a time scale of seconds or minutes, turn over the reins to neurons, which act on a scale of hundredths of a second. The chief contribution of genes comes in advance, in laying down and adjusting neural circuitry, not in the moment-by-moment running of the nervous system. Genes build neural structures—not behavior.

An interesting read on brain development. This is another topic I find very interesting.

Related: Feed your Newborn Neurons - How The Brain Rewires Itself - Brain Development Gene is Evolving the Fastest - The Brain is Wired to Mull Over Decisions

August 15, 2007

Raised Without Antibiotics

Tyson is going to start selling chicken Raised Without Antibiotics. The overuse of antibiotics is a huge problem and the overuse in the raising of livestock is a huge problem.

“While we have great confidence in the quality of our traditional chicken, we’re also committed to providing mainstream consumers with the kind of products they want,” said Richard L. Bond, president and CEO of Tyson Foods. “According to our research, 91% of consumers agree it’s important to have fresh chicken produced and labeled ‘raised without antibiotics’,” Bond said.

Tyson started selling 100% All Natural™, Raised Without Antibiotics chicken this week. The product is being distributed nationwide in newly-designed packaging highlighting that the chicken is raised without antibiotics and contains no artificial ingredients.

While it is nice they will start selling a portion of chicken raised without using antibiotics and endangering the health of the community by helping evolve super-resistant bugs this is really a pretty small step I would guess. The risk is not even mainly to the person eating the food pumped full of antibiotics it is to everyone when drug resistant bacteria are evolved through the overuse of antibiotics. Also, 100% All Natural is trademarked? Give me a break.

Nationwide Survey Reveals Most Americans are Unaware They Consume Beef and Poultry Raised on Antibiotics (2003)

“Antibiotic medicines are losing effectiveness on humans due to their increased use in animal feed,” said Margaret Mellon, Ph.D, JD, director of the food and environment program for the Union of Concerned Scientists. “Animals raised in natural environments rarely require the use of antibiotics. Americans who choose meat produced this way are making conscious decisions to ensure that antibiotics will still be working when they or their family need them.” The Union of Concerned Scientists estimates that 70 percent of all antibiotics in the United States are now fed to animals raised for human consumption in order to hasten the animals’ growth or prevent illness amid crowded, unsanitary conditions on factory farms.

Abuse of Antibiotics at Factory Farms Threatens the Effectiveness of Drugs Used to Treat Disease in Humans:

According to the Center for Disease Control, more than one-third of the salmonella poisoning cases in 1997 were found to be resistant to five antibiotics. Drug resistance in campylobacter bacteria, the most commonly known cause of bacterial food-borne illness in the United States, increased from zero in 1991 to 14 percent in 1998.

The European Union, on the recommendation of the World Health Organization, has banned the use of antibiotics to promote the growth of livestock animals when those drugs are also used to treat people. The Center for Disease Control has agreed with this position, but the U.S. government has failed to reduce the threat that ineffective antibiotics pose to human health. (Lieberman, et.al., 1999)

To reduce serious health threats, the Food and Drug Administration should ban the use of antibiotics to promote livestock growth when those antibiotics are used to treat humans.

June 25, 2007

Tracking the Ecosystem Within Us

Gut Check: Tracking the Ecosystem Within Us

For more than 100 years, scientists have known that humans carry a rich ecosystem within their intestines. An astonishing number and variety of microbes, including as many as 400 species of bacteria, help humans digest food, mitigate disease, regulate fat storage, and even promote the formation of blood vessels. By applying sophisticated genetic analysis to samples of a year’s worth baby poop, Howard Hughes Medical Institute researchers have now developed a detailed picture of how these bacteria come and go in the intestinal tract during a child’s first year of life.

Before birth, the human intestinal tract is sterile, but babies immediately begin to acquire the microbial denizens of the gut from their environment — the birth canal, mothers’ breast, and even the touch of a sibling or parent. Within days, a thriving microbial community is established and by adulthood, the human body typically has as many as ten times more microbial cells than human cells.

The results, said Palmer, were striking: the group found that the intestinal microbial communities varied widely from baby to baby - both in terms of which microbes were present and in how that composition changed over time. That finding, she said, is important because it helps broaden the definition of healthy microbial colonization in a baby.

Another intriguing observation, Palmer noted, was a tendency for sudden shifts in the composition of the infants’ intestinal microbial communities over time as different species of bacteria ebbed and flowed.

I find this area and this study fascinating. I’m not exactly sure why this study and the incredibly significant positive bacteria for human life news doesn’t get more notice. Oh well I guess there are not cool pictures of robots or scary stories of potential threats to those reading which makes the news less interesting to some. Still I find this stuff amazing: Energy Efficiency of Digestion - Beneficial Bacteria - Skin Bacteria - Hacking Your Body’s Bacteria for Better Health - Where Bacteria Get Their Genes

March 9, 2006

Avian Flu

Bird Flu Virus Microscope Photo

Photo of the Bird Flu virus, courtesy of 3DScience.com.

Avian Flu (site broke link so I removed it), World Health Organization Meeting to Discuss Avian Flu Pandemic as Bird Flu Continues to Spread Through Europe

World Health Organization officials are meeting in Geneva to consider the possibility of a global human bird flu pandemic as the deadly H5N1 strain continues to spread rapidly in birds.

Top influenza official Margaret Chan said the outbreak in poultry is historically unprecedented. She said the deadly virus presents a greater challenge to the world than any other emerging infectious disease.

The meeting was called to plan a response in case the bird flu virus mutates into a widespread human flu virus.

March 6, 2006

Drinking Soda and Obesity

Scientists in food fight over soda (bozos at CNN deleted the webpage):

Biologically, the calories from sugar-sweetened beverages are fundamentally different in the body than those from food.

The main sweetener in soda — high-fructose corn syrup — can increase fats in the blood called triglycerides, which raises the risk of heart problems, diabetes and other health woes.

This sweetener also doesn’t spur production of insulin to make the body “process” calories, nor does it spur leptin, a substance that tamps down appetite, as other carbohydrates do, explained Dr. George Bray of the Pennington Biomedical Research Center in Baton Rouge, Louisiana.

“There’s a lack of fullness or satiety. The brain just seems to add it on,” said Dr. Louis Aronne, a Weill-Cornell Medical College doctor who is president of the Obesity Society.

As with so much life science the “answers” are not clear (Medical Study Results Questioned - Why Most Published Research Findings Are False). The article presents arguments from those who disagree about the link between drinking soda and the dramatic rise in obesity in the USA.

Another article on the topic: Cutting Sugary Drinks at Home Helped Teens Shed Pounds by Judith Groch.

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