Friday, December 29, 2006
The team used an innovative DNA test to catalog the bacteria in air samples taken from the Texas cities of San Antonio and Austin. Surprisingly, they found a widely varied bacterial population that rivals the diversity found in soil. They also found naturally occurring relatives of microbes that could be used in bioterrorist attacks - although many of these relatives are harmless.
“Before this study, no one had a sense of the diversity of the microbes in the air,” says lead author Gary Andersen of Berkeley Lab’s Earth Sciences Division.
The research, which will be published this week in the online early edition of the Proceedings of the National Academy of Sciences, serves two purposes. It paves the way for regional bacterial censuses that will help a Department of Homeland Security bioterrorism surveillance program differentiate between normal and suspicious fluctuations in airborne pathogens. It will also help scientists establish a baseline of airborne microbes, which they can use to track how climate change affects bacterial populations.
“We want to determine the background levels of airborne pathogens and other microbes because only very limited work has been conducted on cataloging organisms in the air,” says Andersen. “This work underscores how much we don’t know about airborne bacterial populations, or where the bacteria come from.”
In the past, scientists relied on bacterial cultures to determine what microbes are present in an air sample. In this method, the culture media is exposed to the sample, and whatever grows is counted. Unfortunately, this approach leaves out all of the organisms that can’t survive in the culture, which in some cases is as much as 99 percent of the bacteria in a sample.
In this census, however, Andersen and colleagues used a vastly more comprehensive test developed by Todd DeSantis, who is also with Berkeley Lab’s Earth Sciences Division. Their DNA microarray probes air samples for a gene involved in making proteins, called 16S rRNA, which is found in all bacteria. The square-shaped microarray, which is called PhyloChip and is roughly the size of a quarter, can detect up to 9,000 different types of this gene, each unique to a different type of bacteria. The microarray is sensitive enough to differentiate among these thousands of gene sequences, meaning it can analyze an air sample and list every type of organism present.
To conduct the study, daily air samples were taken at several locations in San Antonio and Austin over a 17-week period. The samples were sent to Berkeley Lab where they were analyzed by the microarray. It found 1,800 types of bacteria, including some pathogens, wafting in the air over the two cities. This diverse population matches the complexity of soil populations, which is considered to be one of the richest habitats for microbes.
The scientists also sought to determine whether background levels of airborne bacteria change from city to city, or are generally the same throughout a region. To explore this question, they chose Austin and San Antonio because the two cities have similar population densities, elevation and topography, and they are only about 100 kilometers apart. After taking into account these common characteristics, they determined that the two cities shared a similar microbial composition.
“This gives us hope that we can eventually develop a regional airborne microbial census, perhaps even a nationwide or global census,” says Andersen. “This will also help us determine the sources of airborne bacteria. Does it come from nearby farms and water treatment plants, or is it imported by the wind from another state or country?”
The team also determined that location was not as strong a source of microbial variation as time and weather. Specifically, the time of the year during the 17-week testing period was the most significant source of variation, followed by atmospheric conditions. For example, warmer and dryer conditions led to increased amounts of spore-forming bacteria.
“This information may help explain temporal spikes, which is important in bioterror surveillance,” adds Eoin Brodie, also with Berkeley Lab’s Earth Sciences Division. “A spike may not be due to a biological attack, but to normal weather fluctuations that draw bacteria up from their natural reservoir.”
In this way, bacterial censuses can help explain whether a pathogen’s presence is natural or indicative of a biological attack. In one example, the team detected relatives of Francisella tularensis, a naturally occurring bacterium that causes tularemia, also known as rabbit fever. This especially potent bacterium is a possible candidate as a bioterror weapon. But it’s also very common. Tularemia has been reported in all U.S. states except Hawaii. This natural background can confound the detection of a terrorist attack and trigger false alarms. The trick is to determine whether the amount of F. tularensis detected in an air sample is in synch with normal levels, or if it’s suspicious.
“Almost all of the bacterial bioterror pathogens are in the environment and in the air naturally, so we need to find their natural backgrounds,” says Andersen.
An airborne bacterial census will also enable scientists to track how climate change impacts the microbial composition of the atmosphere. This process is already occurring. Wind-blown dust and biomass from Africa’s expanding Sahara desert are reaching North America in significant quantities. Recent research links this dust to an increase in asthma cases in the Caribbean.
“We need to determine what’s in the air, so we can determine how climate change affects microbial diversity,” says Andersen. “We found that there are a lot of airborne bacteria, including pathogens, which we did not know are out there.”
“Urban aerosols harbor a diverse and dynamic bacterial population” is published in the online edition of the Proceedings of the National Academy of Sciences. In addition to Andersen, Brodie and DeSantis, fellow Earth Sciences Division scientists Jordan Moberg, Ingrid Zubietta, and Yvette Piceno contributed to the research. The research was funded by the Department of Homeland Security and the Department of Energy.
Contact: Dan Krotz
DOE/Lawrence Berkeley National Laboratory
Tags: science, health, air, study, Berkeley, bacteria, disease, conditions, microbes, bioterror, sample, terrorism, news
The study is published in Cancer Epidemiology Biomarkers & Prevention.
The research was funded by Cancer Research UK and led by Petra Lahmann of the Department of Epidemiology, German Institute of Human Nutrition Potsdam-Rehbrücke, in Nuthetal, Germany, and a widely constituted international team of researchers.
While much research extols the virtue of physical exercise as a way to reduce breast cancer risk, the evidence on precisely what type of activity is most beneficial is scanty.
Petra Lahmann and colleagues used data on over 200,000 premenopausal and postmenopausal women aged between 20 and 80, from 9 European countries.
They used statistical regression models to work out a metabolic-equivalent rate for the various forms of exercise the women undertook so that they could compare the "physical activity value" of the different forms of exercise.
They also took into account demographic, social and medical factors such as age, age when menstruation started, body mass index, education, geographical location, alcohol consumption, age at first pregnancy, oral contraception and hormone replacement therapy.
The women's physical activities were classified into three groups: recreational, household, and occupational, and a total of all three was also calculated. The women were followed up over a 6.4 year period, during which time 3,423 invasive breast cancers occurred in the group.
The results suggest that total physical activity reduces risk of breast cancer only in postmenopausal women. However, and perhaps more surprisingly, housework on its own reduces breast cancer risk in both pre- and postmenopausal women - the former by 19 per cent and the latter by 29 per cent. The study found no significant link between reduced breast cancer risk and either leisure or work-related physical activity.
The women spent an average of 16 to 17 hours a week on household chores such as washing, cooking and cleaning.
The researchers mention in the study that their findings on housework and reduced breast cancer risk are in line with other research, but point to the low numbers of women in the study who were classed as "active" in job-related activity as to the possible reason why no link was found in that area.
Their main conclusion is that this study supports the growing body of evidence showing strong links between physical activity and reduced breast cancer risk. This is in line with the general message from Cancer Research UK who promote taking regular exercise and maintaining a healthy body weight as the main way to reduce cancer risk.
"Physical Activity and Breast Cancer Risk: The European Prospective Investigation into Cancer and Nutrition."
Cancer Epidemiology Biomarkers & Prevention, Published online first on December 19, 2006
Click here for Abstract.
Written by: Catharine Paddock
Writer: Medical News Today
Tags: cancer, breast cancer, health, diet, wellness, hygiene, hand washing, study, prevention, housework, help, menopause, activity
The research study was led by Dr Rachel Kimbro from the Department of Population Health Sciences at the University of Wisconsin-Madison and two colleagues from Columbia and Princeton Universities.
The study is published in American Journal of Public Health.
Dr Kimbro and her colleagues looked at the ethnic and racial differences and levels of obesity in 2,000 three-year old toddlers in a nationwide sample drawn from low-income urban families in 20 cities. 35 per cent of the children were classed as overweight or obese.
Their methods included observing and interviewing the families at home at three points in the toddlers' lives: aged 0 (at birth), 1 and 3 years. They analyzed the data statistically using regression analysis to find out how ranges in overweight and obesity levels varied with race/ethnicity and what they observed.
The results showed that the Hispanic children were twice as likely to be overweight or obese as black or white children, but they could not find out why. However, they did show that weight at birth and whether the baby took a bottle to bed were strongly linked to obesity risk. 14 per cent of the Hispanic toddlers took a bottle to bed at age 3, as compared with 6 per cent of the whites and 4 per cent of the blacks.
Another significant factor was the weight of the mother - obese 3 year olds were more likely to be linked to with obese mothers.
The researchers wondered whether cultural differences, might explain some of these variances. For instance, is it possible that Hispanic communities regard chubbiness as a healthy sign in toddlers?
The researchers concluded that even as early as aged 3, problems with being overweight are evident, and that in low-income families, Hispanic children with overweight mothers are the ones most likely to be obese themselves.
"Racial and Ethnic Differentials in Children’s Overweight and Obesity Among 3-Year-Olds."
Rachel Tolbert Kimbro, Jeanne Brooks-Gunn, Sara McLanahan.
AJPH Dec 28, 2006, 10.2105/AJPH.2005.080812
First Look, published online ahead of print.
Click here for Abstract.
Written by: Catharine Paddock
Writer: Medical News Today
Tags: obesity, hispanic, toddlers, children, fat, health, diet, Pre-School, US, poor, study, university, public health
The proposed ruling was issued yesterday, December 28th, and is currently in draft status, until the 90-day public consultation elapses after which it will be made final.
The FDA's proposed ruling is in three parts: a risk assessment, a risk management plan, and information for the food industry.
The risk assessment proposes that eating meat and milk from cloned adult cattle, pigs, goats and their offspring is as safe as eating those products from animals reared in the conventional way. Sheep are not mentioned because there is not enough evidence on sheep cloning to give a reliable risk assessment.
The FDA investigated the relevant scientific evidence and an independent panel of experts on animal health and cloning reviewed and agreed with their findings. The findings are in line with a 2002 report from the National Academies of Sciences.
Dr Stephen Sundlof, Director of FDA's Center for Veterinary Medicine said in a press release yesterday: "Based on FDA's analysis of hundreds of peer-reviewed publications and other studies on the health and food composition of clones and their offspring, the draft risk assessment has determined that meat and milk from clones and their offspring are as safe as food we eat every day."
Dr Sundlof adds that cloning presents no added risk when it is compared to the "other assisted reproductive technologies" currently used by US farmers.
The risk management plan outlines measures that the FDA recommends for the care of animals used in or resulting from cloning technology. They also ask that producers hold back from selling food from cloned animals until the consultation process has elapsed, its outcome is reviewed and the FDA's final ruling is made.
Cloning is where a cloned animal is a genetic copy of its donor "sibling" - in the same way as identical twins have the same genetic code because they come from the same egg and sperm. The difference is that the clone does not start life in the womb alongside its "sibling", but at a later stage, from cells taken from an adult donor. So it is like having identical twins but one is already an adult when the other is born.
The cells from the donor are inserted into an egg from which the DNA has been removed, so that only the donor's DNA is present in the ensuing embryo, which gestates in the womb of a "surrogate mother" and is born in the normal way.
Dolly the sheep, born in 1997 and named after Dolly Parton, is a famous example of a cloned animal.
Cloning happens in the plant world all the time - every time you take a cutting and grow it into a mature plant you have cloned an identical specimen. Some grape vines today are clones of originals that existed in the Roman times over 2,000 years ago.
Cloning is not the same as genetic engineering (also called genetic modification (GM), or gene splicing). Genetic engineering involves altering the gene pattern of an existing organism, and does not result in the production of a genetically identical "twin". Genetic engineering technology now lies behind the production of human insulin (produced from genetically altered bacteria), herbicide resistant crops, and many other medicine and food related applications.
Click here to view the Draft Risk Assessment Papers on Animal Cloning (FDA).
Click here to read about Dolly the sheep, 1996-2003 (Science Museum, UK)
Written by: Catharine Paddock
Writer: Medical News Today
Tags: meat, FDA, cloning, topics, controversy, safe, healthy, food, cloned meat, science, risk, management, safety, public, input
Thursday, December 28, 2006
In making this announcement Universal Studio's executive chef of Parks and Resorts, Steven Jayson, said that they while they want their guests to feel good about their food, they also want them to retain the element of choice, "that is why our program is about choices rather than absolutes". Universal Studios have been researching healthy alternatives and eliciting customer feedback and Jayson adds that "We did not want to sacrifice taste or quality. It’s important for our guests to know that healthy food can taste good."
Artificial trans-fats are made from vegetable oils that are hydrogenated to make them easier to use in processed foods such as pastry and confectionery, and to keep it semi-solid like butter for frying and spreading and to extend its shelf-life because it takes longer to go rancid. While this makes it more convenient for food producers, research has shown that a diet high in trans-fats contributes to obesity and heart disease.
Natural trans-fats do exist but they form a very small proportion of the natural fat we eat, so the term "artificial trans-fat" has become shortened to "trans-fat".
Trans-fats are not saturated fats (their chemical structure includes double carbon-carbon bonds, whereas saturated fats have only single carbon-carbon bonds), they are in fact partly saturated, retaining the same ratio of hydrogen to carbon atoms as naturally occuring poly-unsaturated fats. It is thought the problem lies in the structure of the trans-fat molecule.
The term "trans" comes from the shape of the fat molecule that is produced when the vegetable oil is hydrogenated. Hydrogenation simply means the double and triple bonds between some of the carbon atoms in the poly- or mono-unsaturated vegetable oils are broken to cause hydrogen atoms to become attached to them instead.
The problem with trans-fats seems to lie in the fact that when hydrogen atoms are added to the carbon-carbon bonds, they form a transverse pattern, lying on alternating opposite sides of the carbon-carbon link. This is different to the "cis" configuration, more common in naturally occuring fatty acids, where the hydrogen atoms lie next to each other on the same side of the carbon-carbon link.
It is possible that it is this "trans" spatial configuration that interferes with the fat's properties, for example when it interacts with cholesterol. Although chemically different to saturated fats, trans-fats act like them by raising the level of bad cholesterol (LDL). However, unlike saturated fat they have another undesirable effect - trans-fats also lower the level of good cholesterol (HDL).
So in a way, trans-fats are even more harmful than saturated fats as a prime source of fatty acids in our diet. That's what all the fuss is about.
The average person in the US consumes 2.2 kg (nearly 5 pounds) of (artificial) trans-fats in a year.
Healthy Eating Pyramid from the Harvard School of Public Health.
Announcement and dining options at Hollywood Universal Studios.
Written by: Catharine Paddock
Writer: Medical News Today
Tags: theme parks, Trans Fat, Hollywood, Universal Studios, restaurants, New York City, Christmas, New Year, Trans-Fat Free, news, policy, diet, health
The research was led by Carlos Iribarren of the Research Division of Kaiser Permanente of Northern California in Oakland and is published in the American Journal of Epidemiology.
Body Mass Index (BMI) was once used as a measure to predict heart disease risk. However, you could have a high BMI because you are muscular as opposed to fat. So the scientists in this study decided to look at another factor known as SAD, short for sagittal abdominal diameter, a measure of "visceral obesity".
SAD is also called "supine abdominal height" which has been used to predict mortality in men, and is a measure of the girth around the abdomen at a height that is half way between the top of your pelvis and your lower ribs. It is considered a more reliable measure of a person's girth than the waistline, and the measurement is taken by a health professional using a caliper.
The scientists performed a cohort study involving 101,765 male and female members of the Kaiser Permanente of Northern California who had been through health checks between 1965 and 1970 where their SAD was recorded, and who were followed up 12 years later.
After adjusting for a number of social and lifestyle factors such as age, sex, education, BMI, smoking, alcohol and HRT in women, they found that men in the top 25% of SAD girth measurement had a 42 per cent higher risk of coronary heart disease (CHD) than those in the bottom 25% of SAD girth measurement. For women the figure was 44 per cent.
Iribarren and his team also looked at the results within categories of BMI. They found that within the same BMI range, the SAD measure was a reliable predictor of CHD risk. In other words, two people with the same Body Mass Index (even if their weight was "normal") would effectively have different risks of developing CHD depending on the size of their belly - the larger the belly the bigger the risk.
They also found that SAD was a consistent predictor for CHD across racial groups. However, the younger a person was, regardless of race, the stronger the link between SAD and eventually having CHD. The team found this to be unsurprising since the younger you are when you develop a large belly the more likely you are to have complications later in life.
The researchers concluded that "standing sagittal abdominal diameter was a strong predictor of CHD independently of BMI and added incremental CHD risk prediction at each level of BMI".
"Value of the Sagittal Abdominal Diameter in Coronary Heart Disease Risk Assessment: Cohort Study in a Large, Multiethnic Population."
Carlos Iribarren, Jeanne A. Darbinian, Joan C. Lo, Bruce H. Fireman and Alan S. Go.
American Journal of Epidemiology 2006 164(12):1150-1159; doi:10.1093/aje/kwj341
Association for the Study of Obesity (UK).
Written by: Catharine Paddock
Writer: Medical News Today
Tags: stomach, diet, heart disease, obesity, study, BMI, health
Thursday, December 21, 2006
Anemia during pregnancy is a somewhat common problem. If you think you might be anemic it's important to seek care for the sake of your own health and that of your baby.
Anemia is described as a condition in which your red blood cell count is low. Red blood cells help carry oxygen to the rest of your body. An anemic person is not making enough red blood cells and as a result their health may suffer.
When you are pregnant your red blood cells generally increase. Plasma also increases but at a quicker rate. A hemocrit reading is recommended to get an adequate measure the amount of red blood cells in your bloodstream. The hemoglobin level is also tested which analyzes the amount of protein in your blood. Anemic people tend to have a hemocrat reading that is lower than 37 and their hemoglobin is fewer than 12.
Hemocratic testing is usually done at the first prenatal visit along with other routine lab work. It will likely be re-tested when you are further along and more often if you are anemic or show signs of possible anemia.
One problem with anemia duringis that once you go into labor you're at an increased risk of losing large amounts of blood and requiring a transfusion. If you are anemic, special care may be provided and it's wise to follow your care provider's advice on diet changes and the use of supplements.
Some signs of possible anemia include: sleepiness and getting worn out easily, faster than average heart beat especially when you are exercising or pushing your body too much, headache, shortness of breath, lack of ability to concentrate for long periods of time, pale skin, leg cramps, and dizziness.
There are several different kinds of anemia but duringthe most likely type is iron-deficiency. If you are lacking iron then your body is unable to produce adequate amounts of red blood cells which results in iron-deficiency anemia. During the baby uses some of your body's of iron to make its own blood so it's important to make sure you have enough iron stored up for yourself as well. Some signs of iron-deficiency include: fatigue, weakness and pica cravings (wanting to eat things such as clay, ice, soap, toilet paper).
While iron deficiency can possibly lead to anemia it's not always the case. It should be monitored and tested by your midwife or OB so that you and your baby can be healthy and continue developing properly.
Other less common forms of anemia include sickle cell anemia, lead poisoning anemia, b12 deficiency anemia, and chronic red blood cell destruction. Each have different signs and symptoms as well as treatment plans so it's important to see a health care provider if you suspect you might be anemic, especially if you are pregnant or would like to conceive in the near future.
Wednesday, December 20, 2006
COPD, chronic obstructive pulmonary disease, is the fourth leading cause of death in the United States. COPD claims well over one hundred thousand lives each year, with eighty to ninety percent of those individuals being smokers. COPD refers to a pair of conditions, chronic bronchitis and emphysema, that affect the person's lungs, making it harder and harder for them to breathe. COPD is one of this country's most rapidly growing health problems, with sixteen million people suffering from chronic bronchitis and another two million with emphysema.
Although the primary cause of COPD is smoking, it can also be brought about by exposure to air pollution, second-hand smoke, certain industrial pollutants, and some inherited conditions. COPD costs Americans almost forty billion dollars a year in related health care costs. COPD is more common in men, but women are making strides in this race that neither sex wants to emerge victorious in, as more and more women develop COPD, a result of the increase in women smokers after World War II. COPD patients have a poor quality of life in the majority of cases, and the toll that COPD can take on family and loved ones can be devastating.
Someone with chronic bronchitis will experience chronic inflammation of the large air tubes of the respiratory system as a result of the steady exposure to cigarette smoke. This inflammation causes these bronchial airways to narrow, and glands in the lining of these airways secrete excess mucus, causing even more narrowing, with airflow being blocked. This form of COPD will produce a constant cough that will produce sputum composed mainly of mucus, along with a shortness of breath. COPD increases the chance of infection, as chronic bronchitis victims have damaged cilia in their lungs. These minute hairs are responsible for ridding the airways of foreign particles and bacteria, but when they cannot do their job, infections can take hold. Chronic bronchitis worsens over time, and the person afflicted with it often does not realize how serious the problem isCOPD caused by emphysema sees the individual distressed with the condition overproduce an enzyme called elastase. This is a consequence of smoking, and it results in irreversible harm to a protein in the lungs that maintains the structure of the walls of these organs. Emphysema patients find themselves with less elastic lungs than non-smokers, and they transfer less and less oxygen to the bloodstream because of this. COPD from emphysema victims have a great deal of trouble exhaling, as they cannot keep their airways open. Over ninety percent of those with emphysema are older than forty-five, with most of those older than sixty-five showing that the disease is the result of long-term smoking. Symptoms include coughing and extreme shortness of breath, and those with emphysema cannot tolerate much exercise at all. Those with chronic bronchitis can develop emphysema later on, and both diseases can cause respiratory failure as the blood has an awfully low level of oxygen in it, and elevated carbon dioxide amounts.
As COPD progresses in a patient, they often require supplemental oxygen to be able to breathe. Half of those with COPD will see it affect their ability to work, and seventy percent of these people will be unable to exert themselves normally. COPD treatments cannot cure the condition; they can only help to lessen the symptoms, which will worsen over time. Bronchodilator medications are employed to open airways to allow somewhat easier breathing and can be inhaled in aerosol form or taken orally. COPD patients are extremely vulnerable to infections such as pneumonia and influenza, which ultimately will take their lives, as their resistance to them is incredibly compromised. Vaccinations and antibiotics help towards this end. Corticosteroids can help to block inflammation of the airways and are usually inhaled.
Lung transplants have been successful in some end-stage COPD patients, enabling them to live a little bit longer. Lung volume reduction surgery removes the damaged areas of the lungs and joins the remaining regions together, with a mortality rate of fifteen in a hundred and many complications. The quicker COPD is diagnosed, the better the prognosis for those that are found to have it. Quitting smoking is imperative for those with COPD, as the average survival rate for people who are diagnosed with this disease after they have lost over half of their lung functions is under ten years, but much, much less if they insist on continuing to smoke.By: Lindell
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