Some people are resistant to antidepressants.

January 13th, 2010

New research is giving scientists a greater understanding of how a brain becomes susceptible to depression and anxiety on a molecular level and why some people are resistant to antidepressants.

Scientists think two things — biological factors and stressful life events — cause the mental disorders. Antidepressants are available to treat them, often by increasing serotonin levels, but they don’t always work.

“Unfortunately, more than half of all depressed patients fail to respond to their first drug treatment,” senior study author Rene Hen, of Columbia University, said in a news release. “The reasons for this treatment resistance remain enigmatic. Elucidating the exact nature of both the factors predisposing to depression and the mechanisms underlying treatment resistance remains an important and unmet need.”

In the study, researchers used mice to investigate the way the brain deals with serotonin. The brain’s mechanism for handling serotonin appears to be related to levels of so-called “autoreceptors,” the study authors found. Mice with higher levels didn’t respond to treatment with antidepressants, but they did better when the levels went down, the study showed.

The research could lead to treatments to make people more responsive to antidepressants before they take them, Hen said.

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Osteoporosis prevention research

December 22nd, 2009

UK scientists curious to discover why unlike the weight-bearing bone in our limbs, skull bone does not get thin as it ages, even in post-menopausal women, have found some quite remarkable differences between the two bone types that could help develop new treatments and prevent osteoporosis.

Researchers at Queen Mary, University of London, led the investigation, which was published last week as a study in the open access journal PLoS ONE.

Lead author, Dr Simon Rawlinson, Lecturer in Oral Biology at Queen Mary, University of London, told the press that the discovery was exciting because it tells us why our skulls remain tough while the bones in our arms and legs weaken as we age; thus helping us understand osteoporosis better:

“And this has opened up many new lines of research into how the disease could be treated or even prevented,” he added.

Osteoporosis causes bones to become fragile and easy to break: it is more common in older people, especially women past the menopause. Among people aged 50 and over, half of women and one fifth men suffer from the condition, and as our populations age, the numbers of cases and deaths increase accordingly.

Unlike the skeleton one might remember hanging lifeless in the corner of the biology lab at high school, bone is not a dead material but a living, dynamic, and finely balanced system of bone formation and breakdown: with cells called osteoblasts making new bone by producing a “matrix” that then becomes mineralized, while cells called osteoclasts break it down.

Rawlinson and colleagues suggested that one explanation for why skull bone does not get thinner with age like limb bones do is because it has different bone matrix characteristics due to differences in osteoblasts.

For the study, they compared cells taken from the skull and limb bones of adult rats and found differences in appearance and behaviour in the lab, more specifically at the “organ, cell and transcriptome levels”.

They found that:
Limb bones “contain greater amounts of polysulphated glycosaminoglycan stained with Alcian Blue and have significantly higher osteocyte densities than skull bone”.

Patterns for limb and skull bone were different when their cells were cultured and treated with oestrogen, which appeared to affect limb bone far more strongly.

Cultures of limb and skull bone cells also showed differences in gene expression.

There was an astonishing total of 1,236 differences; meaning that about 4 per cent of the genome showed different levels of activity in the two types of bone cell.

Some of the genes affected are known to be involved in making healthy bones.
Rawlinson and colleagues suggested that because the differences between limb and skull bone were so profound, they must arise early in life, probably at the stage when they are still forming in the womb.

“We assign these differences, not to mode of primary ossification, but to the embryological cell lineage,” they wrote.

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Australia suffers from obesity and high blood pressure

December 11th, 2009

Cardiovascular medications account for almost a third of all drugs doled out in Australia, and a majority of them are meant for lowering blood pressure, a new report released today stated.

According to the report, physical inactivity, obesity and high cholesterol affects over 50 per cent of adults, while smoking and high BP affect 20-35 per cent of adults, which was approved by Lynelle Moon, Head of the AIHW’s Cardiovascular Disease, Diabetes and Kidney Unit.

In some cases the occurrence of risk factors was on a rise, following obesity prevalence rising from 11 per cent of adults in 1995 to 24 per cent in 2007-08.

Dr*gs for blood pressure alone accounted for 20 per cent of all drugs dispensed, with four off patent blood pressure-lowering medications like ramipril, perindopril, irbesartan and frusemide. These were in the top 10 most commonly supplied drugs of 2007.

Between 1995 and 2005 there was a 13-fold rise in the use of statins, with atorvastatin, simvastatin and pravastatin being the most common in 2007.

Risk factors are being tackled through population level interventions such as awareness campaigns and school programs, but there is little data available on these activities.

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Loosing hair because of high blood pressure?

December 11th, 2009

Hypertension has been linked to heart disease, diabetes and early mortality. But hair loss?
Scientists are not exactly sure why, but a number of studies have suggested a relationship between blood pressure and men’s baldness, particularly the early-onset kind.

In a study published in 2007, for example, researchers looked at 250 men ages 35 to 65. After controlling for age, high cholesterol, smoking and other variables, they found that hypertension was “strongly associated” with male pattern baldness: those with a blood pressure reading above 120 over 80 had twice the risk of the others.

Other studies have suggested a link between baldness and heart disease. For a 2000 study in The Archives of Internal Medicine, for example, researchers analyzed health records for 22,000 male doctors over 11 years, examining many aspects of their health. Men with mild balding of the crown had a 23 percent higher risk for heart disease, and those whose crowns were completely bald had a 36 percent greater risk.

But the relationship is only a correlation. Researchers suspect hair loss could be among many markers of an increased risk of hypertension, caused in part by higher levels of testosterone and other hormones, and more androgen receptors in the scalp.
Studies suggest that hair loss may indicate an increased risk of high blood pressure and heart disease.

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Taking antibiotics correctly

December 11th, 2009

Most of us have heard the cardinal rules of antibiotics.
Don’t take them when they aren’t needed. And when they are prescribed, take every last pill – do not stop just because you start to feel better. There are other rules, however, that many of us may not know. And some myths that we think are true but are not.
The missing information and the misconceptions can keep you from taking antibiotics appropriately, meaning you may not get the maximum benefit and may put yourself at risk of developing a drug-resistant infection in the process.
Taking the pills correctly may be at least as important as taking all of the pills in your prescription, experts say.
Interactions with foods, other drugs and even supplements like multivitamins can interfere with the body’s ability to absorb antibiotics. The consequence? You end up getting a lower dose than you need to kill those germs.
“If it isn’t being absorbed, for whatever reason … then it’s not going to get to the site of infection at adequate levels to appropriately treat the infection,” Dr. Andrew Simor, chief microbiologist at Toronto’s Sunnybrook Health Sciences Centre, explains.
“And you run the risk of not responding to treatment or of having sub-therapeutic levels of an antibiotic that can promote resistance.”
But taking antibiotics properly can be tough, especially if you are prescribed one of the older types. Some newer antibiotics use a one-pill-a-day regimen, but older types may require you to pop three or four pills a day – on an empty stomach.
Remembering to take them an hour before eating or a couple of hours after eating can be difficult. But forgetting and taking them on even a semi-full stomach can mean your body only absorbs a half or a quarter of the active ingredient in the drug, says Clarence Chant, a pharmacist at St. Michael’s Hospital in Toronto who works in the intensive care unit and specializes in infectious diseases.
Under those circumstances, you are essentially under-dosing yourself. And that can give rise to antibiotic resistance.
That’s because when you have a bacterial infection, you aren’t harbouring a single bug, but a swarm of a type of bug – whether that’s Strep or Staph or some other bacterium. If you are infected with bacteria that are susceptible to antibiotics, most members of that hoard will be vulnerable to the drug.
But there can be a few in the crowd that have mutations that let them fight off the antibiotic if the level of the drug in your system is too low. If you are getting a sub-optimal dose because you are taking your antibiotics incorrectly, you could end up killing off only the weaker bacteria. The result: The resistant ones survive and thrive.
“That’s why the instructions of how to take an antibiotic are just as important as ensuring you take it for the right duration,” Simor says.
Ideally, antibiotics that are taken three or four times a day should be spaced out evenly, he says. With the ones that need to be taken on an empty stomach, you could find yourself needing to wake up in the night to get all the pills down over a 24-hour period.
But not all antibiotics have to be taken on an empty stomach. The macrolide class of antibiotics – erythromycin is an example – can trigger nausea when taken on an empty stomach. So for them, the recommendation is to take the pills with food.
The range of types of antibiotics and the different ways they are meant to be taken mean you really need to get clear instructions from your doctor and your pharmacist on how to correctly take your meds. Don’t assume the antibiotic for the infection in your chest is taken the same way as the antibiotic you took for that urinary tract infection a couple of years ago.
“The most important thing, I guess, is have a dialogue with the pharmacist when you’re getting a prescription,” says Chant.
Make sure that talk includes a discussion about the other drugs, vitamins and herbal supplements you are taking. They can interact with antibiotics as well.
For instance, an older type of antibiotic called the tetracyclines binds to calcium. That means you don’t want to take them with milk or dairy products. But multivitamins can contain calcium too, so if that is the kind of antibiotic you are taking, you don’t want to take your pills around the time you take your multivitamin, Chant says.
Iron supplements could interfere with absorption of this type of antibiotic as well, he says.
However, something a lot of people believe will interact negatively with antibiotics – alcohol – actually doesn’t in most cases, Simor and Chant say. Alcohol in moderation won’t affect uptake of the active ingredient of most antibiotics.
“It’s probably not a good idea to drink alcohol when you’re sick with an infection, but that’s a different story,” Chant says.
There are exceptions. Metronidazole (sold as Flagyl) can induce severe nausea when a person taking it drinks alcohol. “It varies from drug to drug. But many antibiotics can be taken with small or modest amounts of alcohol,” Simor says.
Just as you need to make sure other medications or supplements don’t interact negatively with antibiotics, you should ask if your antibiotics will have a negative impact on any other drugs you might be taking. And that includes oral contraceptives.
There are differing views on whether antibiotics interfere with absorption of contraceptives. But Chant thinks there might be something to the notion.
“My opinion would be that definitely from … understanding how the antibiotics are handled in your body as well as the oral contraceptives, that there’s definitely some truth to it,” he says.
“I don’t know how well studied it is. … (But) the interaction is probably there. It makes sense pharmacologically speaking.”
The complexity of the possible interactions means there are plenty of chances for things to go awry. If you go to one physician for all your care and see one pharmacist for all your prescriptions, that could minimize the chances of interactions or missteps.
But the reality is that isn’t always possible.
And that means people getting prescriptions for antibiotics need to be their own advocates – making sure they inform the prescribing doctor and the pharmacist of the other drugs and supplements they are taking to maximize the potential for benefit and minimize the risk of adverse interactions.

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MRSA skin infections

December 11th, 2009

Staphylococcus aureus or “staph” is a common germ that about 30 percent of people have on their skin or in their nose. This germ does not cause problems for most people, but sometimes it can cause skin infections, such as pimples or boils, and wound infections. Less commonly, pneumonia or infections in the blood can occur.
Antibiotics are often given to kill staph germs when they cause infections. Some staph are resistant to certain antibiotics. Methicillin-resistant Staphylococcus aureus, or MRSA, is a type of staph that is resistant to some of the antibiotics that are used to treat staph infections.
MRSA is usually spread from person to person through direct skin contact or contact with shared items or surfaces. MRSA may spread more easily among athletes because they have repeated skin-to-skin contact, get cuts and abrasions that allow staph and MRSA to enter and share items and surfaces that come into direct skin contact, such as towels, used bandages and weight-training equipment.
Athletes can protect themselves from getting MRSA and other skin infections by taking a few simple precautions:
Perform hand washing, at a minimum before and after playing sports and after using shared equipment.
Shower immediately after exercise. Do not share bar soap and towels.
Wash uniforms and clothing after each use. Dry clothes completely.
Wear protective clothing/gear designed to prevent skin abrasions or cuts.
Cover skin abrasions and cuts with clean, dry bandages until healed and change as directed by your health care provider.
Avoid sharing personal items such as towels and razors that contact bare skin.
Use a barrier, such as a towel, between your skin and shared equipment, such as weight-training, sauna and steam room benches.
Staph infections, including MRSA, also occur among people in hospitals and health care facilities, such as nursing homes and dialysis centers. These infections are referred to as health care-associated MRSA infections, whereas those that occur in otherwise healthy people who have not been hospitalized or had a medical procedure are known as community-associated MRSA infections. Health care-associated MRSA infections are often more serious.
If someone is a MRSA carrier (bacteria are present on the skin but they are not causing infection) treatment is not usually required. Some MRSA skin infections can be treated by drainage of the boils or abscesses by a health care provider, and antibiotics might not be needed. When a MRSA infection requires antibiotic treatment, there are available options. It is important to take all of the antibiotic doses, even if the infection is getting better.
MRSA bacteria occasionally develop resistance to antibiotics, however, to date, all resistant isolates have been sensitive to alternative drugs. These drugs can have some side effects and can be expensive.

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“Be ware of the chicken”

December 2nd, 2009

The bad news from a new study is that two thirds of store-bought chicken was found to be contaminated with potentially harmful bacteria. The good news is that, believe it or not, the numbers are better than two years ago, when eight out of 10 chickens were found to contain pathogens like salmonella and campylobacter.
The study, to be published in the upcoming issue of Consumer Reports, tested 382 broiler chickens bought from 100 stores around the country. Some brand-name chickens — Tyson and Foster Farms — fared poorly, with salmonella and campylobacter found in more than 80 percent of the samples. Perdue chickens did a little better — 56 percent of chickens tested were found to be free of both pathogens. According to the study, organic “air-chilled” broilers seemed to be a consumer’s best bet because 60 percent of those chickens checked in bacteria-free.
Estimates from the Centers for Disease Control and Prevention say more than a million people have salmonella poisoning every year from a variety of causes. About 25,000 people get so sick they seek treatment at a hospital and about 500 people die every year. Symptoms of an infection generally show up 5-7 days after contamination and can include diarrhea, stomach cramping and fever.
The news that everyday store-bought chickens can be contaminated with harmful bacteria drew a loud “ewww” from several moms shopping for chickens at a local supermarket in Ashland, Mass.

Linda Epstein said she was looking for a broiler chicken to feed her family of four because “it’s easy to make and my fussy kids will actually eat chicken.”

Epstein said she had “no idea” that campylobacter and salmonella could be present in such a high percentage of chickens. “It really kind of makes me sick to my stomach just thinking about it,” she said.
As you might imagine, those words are not music to the ears of the major chicken distributors.
Tyson Foods provided a statement to ABCNews.com calling into question the testing methods of Consumer Reports. “We have confidence in the safety of our chicken but not in the testing by Consumer Reports. Since the Consumer Reports study only confirms the presence of bacteria and not the number it is not a true indication of the safety of our products…the small sample size is also a concern.”

A statement also detailed the company’s efforts to increase the safety of its poultry operations which include “the use of antimicrobial rinses, similar to those used in mouthwashes, as well as organic acids.”
The National Chicken Council released a statement that said, “Chicken is safe. Like all fresh foods, raw chickens may have some microorganisms present, but these are destroyed by the heat of normal cooking.”
But the problem with food-borne bacteria is not just in the cooking. Often an infection can occur because of unsafe washing and handling practices in the kitchen.

Martin Bucknavage, a food safety specialist, at the Penn State College of Agriculture, said cross-contamination – for instance, when salmonella bacteria shows up on a cutting board – can be the biggest danger consumers face. “We have to keep reminding people to wash and clean their utensils, cutting boards and counters. People should just assume there is the potential for bacterial pathogens and act accordingly,” said Bucknavage.

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Mammograms

December 2nd, 2009

Mammograms may actually boost the risk of breast cancer in some high-risk women, a new study suggests.

Dutch researchers analyzed six previously published studies, four examining the effect of low-dose radiation exposure from mammography among women with the genetic mutation boosting breast cancer risk and two looking at the effect of radiation from screening in women with a family history of breast cancer.
“Women who were exposed before the age of 20 had a 2.5 times increased risk of breast cancer,” said Martine Jansen-van der Weide, an epidemiologist and researcher at the University Medical Center Groningen, in the Netherlands. So did women with five or more exposures.

She was to present the findings Monday at the Radiological Society of North America’s annual meeting in Chicago.

No information was available from the studies about the time period, said Jansen-van der Weide. The studies did control for different factors that affect breast cancer risk, such as age, breast-feeding and age at first menstruation.

These new findings come in the wake of a controversial recommendation made in mid-November by the U.S. Preventive Services Task Force for the general public, that women delay routine screening mammograms from age 40 to 50, asking their doctor the best time to begin, and that older women switch to every-other-year mammograms.

Currently, the American Cancer Society and other organizations advise yearly mammograms for women beginning at age 40. For high-risk women, the ACS recommends a mammogram and MRI every year.

Overall, the Dutch researchers also found, the average risk of breast cancer from radiation exposure was 1.5 times greater among the high-risk women studied than the high-risk women not exposed.

The study is important, as it provides the ”first direct piece of evidence on whether high-risk women have an increased risk due to radiation exposure,” said Edward Hendrick, a member of the American College of Radiology Commission, a medical physicist and clinical professor at the University of Colorado at Denver.

In the United States, women under 30 don’t routinely get mammograms, however, he said. It’s known that young women are more radiation-sensitive.

Young women who are deemed high-risk can, if they choose, turn to an MRI breast exam instead, he said. MRIs use magnetic or radio waves, not radiation.

“Screening is very important,” Jansen-van der Weide said. “However, for young, high-risk women, a careful approach is advised when considering mammography for screening.”

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Don’t let pain get you

November 30th, 2009

Older adults who had chronic musculoskeletal pain in two or more places, higher levels of severe pain and/or pain that interfered with their daily activities were more likely to fall than adults who didn’t have those types of pain, according to a study in today’s Journal of the American Medical Association.

“Pain contributes to functional decline and muscle weakness and is associated with mobility limitations that could predispose to falls,” the authors wrote.

They say there could be several causes for the pain-falls relationship, including neuromuscular effects that could lead to leg muscle weakness or slowed responses to impending falls. The pain could cause people to change the way they walk, resulting in instability.

Chronic pain also could be a sufficient distraction to interfere with the thinking ability needed to prevent a fall, they say, noting that preventing or interrupting a fall usually needs a thought-out physical maneuver.

Those weaknesses could occur without people who care for the person who has pain realizing it accompanies the more obvious pain problem. The authors say chronic pain hasn’t gotten sufficient attention as a risk factor for falls in older adults.

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Viruses decline immune response

November 30th, 2009

Illness and death caused by viral infections tend to increase with age, indicating that aging impairs immunity, but the underlying mechanisms are unclear. To understand how aging modifies inflammatory response to viral infection, a research team led by Daniel R. Goldstein, M.D., associate professor of internal medicine and cardiology at Yale School of Medicine, infected young (2-4 months), middle-aged (8-10 months), and aged (18-20 months) mice with the herpes virus. This led to a rapid increase in inflammatory mediators, or cytokines, called interleuken 17. When the team examined the blood for inflammatory substances and examined the liver, they saw evidence of damage in only the aged cohort.
When Goldstein and his team inhibited interleuken 17 either before or after infection, the mice in the aged group no longer showed signs of liver damage and no longer died. Goldstein said the study’s results demonstrate that aged individuals succumb to viral infection due to exaggerated immune responses rather than declining immunity.
“This was a dramatic response to inhibiting a single cytokine,” said Goldstein. “Aged mice do have defective immune responses, but instead of trying to boost their immune response, we should try to inhibit certain inflammatory pathways to prevent susceptibility to viral infections.”
Goldstein said the findings could explain why older people are more susceptible to the seasonal influenza viral infection. “Our study could also explain why other susceptible populations succumb to viruses, such as the H1N1 pandemic virus, since it is possible that heightened immune responses — rather than defective immunity — attack the body and lead to disease in these individuals.”

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