islamabad - Upon observing that stress exacerbates mental illnesses, researchers set out to address the question of whether anxiety damages the brain and whether they could pinpoint mechanisms behind the link between stress and mental illness.

The researchers - led by Dr Linda Mah of the Rotman Research Institute at Baycrest Health Sciences - conducted the research and reviewed that animal and human studies that examined brain areas affected by chronic anxiety, fear and stress.

In detail, they reviewed recent evidence from studies of stress and fear conditioning in animals, as well as neuroimaging studies of stress and anxiety in both healthy people and clinical populations.

For many of us, fear, anxiety and stress are a normal, occasional part of life; we get stressed before taking a test or going for a job interview, for example. It is when these instances of anxiety become more frequent that they interfere with daily life.

The team defines chronic stress as “a pathological state that is caused by prolonged activation of the normal acute physiological stress response,” which can then, in turn, cause problems for the immune, metabolic and cardiovascular systems.

Likewise, chronic stress can cause the brain’s hippocampus to atrophy. This brain area is important for long-term memory and spatial navigation.

Results revealed that there were similar patterns of aberrant brain activity in the wake of fear, anxiety and chronic stress. In detail, the amygdala was overactive and the PFC - which contains the “thinking areas” of the brain that regulate emotional responses - was under active.

Interestingly, over a decade ago, renowned neurologist Dr Helen Mayberg first identified what the researchers call the “see-saw relationship” between the amygdala and the PFC in a breakthrough study.

However, not all hope is lost. Dr Mah also suggests that damage to the hippocampus and PFC as a result of stress is not entirely irreversible. She notes that both anti-depressant treatment and physical activity have both shown promise in increasing hippocampal neurogenesis.

Colorectal cancer drivers differ between younger, older patients

A study presented at a symposium recently shows how differences in colorectal cancer between younger and older patients may be distinguished genetically - a finding that could pave the way for better treatments for younger patients.

The study showed “distinct genetic differences” in tumours sampled from younger and older colorectal cancer patients, says investigator Christopher Lieu, assistant professor of medical oncology at the University Colorado School of Medicine, in Aurora.

Prof Lieu and colleagues note recent data also suggests that younger patients are at higher risk of disease progression and death from the cancer.

The purpose of the new study is to look more closely at any genetic causes that might explain why colorectal cancer appears to be more aggressive when it hits younger people.

The researchers note that they found, “in total 77 genes were enriched in younger patients compared with older patients and 23 genes were enriched in older patients compared with young patients.”

Many of the enriched genes of the younger patients’ tumours are known to be important for signalling pathways involved with cell proliferation commonly associated with cancer.

In contrast, in the older patients’ tumours, they found the enriched genes were mostly involved in cell differentiation as opposed to cell proliferation.

The researchers point out FDA-approved therapies that target one of the genes that came up in the younger patient sample - ERBB2 (Her2/neu) - are already available.

They are partway there, in that they already have a collection of tumor samples grown from the tissues of young colorectal cancer patients - which are needed for preclinical genetic and drug testing.

Exposure to airborne ultrasound can harm health: Study

Have you ever experienced nausea while waiting for your train? Or developed a sudden headache while out shopping? While there are likely numerous explanations for such occurrences, a new study suggests exposure to airborne ultrasound could be one.

The study suggested that the general public are unaware that they are being exposed to very high-frequency (VHF) sound and ultrasound (US) at levels over the current guidelines.

Such exposure could be putting people’s health at risk, a UK researcher claims, causing headache, nausea, dizziness, migraine and tinnitus - ringing in the ears. These are symptoms that have been reported in occupational settings among workers exposed to high sound frequencies through drilling, for example, or industrial cleaning devices.

However, study author Prof. Tim Leighton, of the University of Southampton in the UK, notes that such guidelines are only applicable to workplaces in which employees are aware of their ultrasound exposure, enabling them to protect themselves against any possible health implications.

“The guidelines are also based on an insufficient evidence base, most of which was collected over 40 years ago by researchers who considered it insufficient to finalize guidelines, but which produced preliminary guidelines,” notes Prof. Leighton.

“This warning of inadequacy was lost as regulatory bodies and organizations issued ‘new’ guidelines based on these early guidelines, and through such repetition, generated a false impression of consensus.”

Sound frequencies were recorded in a variety of public buildings in the UK, including train stations, libraries, museums, schools and sports stadiums - places where there had previously been reports of people experiencing symptoms that could be related to ultrasound exposure.

Prof. Leighton notes that there are a variety of ultrasound sources present in public places, including loudspeakers and door sensors.

The buildings assessed in the study were occupied by hundreds of people at the time of recording, he notes.

Data showed that the general public occupying the buildings were being exposed to VHF/US at levels over 20 kHz, which Prof. Leighton says has the potential to be a public health concern.

Prof. Leighton also calls for new guidelines that address the potential harms of ultrasound exposure among the general public.

These new guidelines should not be based solely on selection of ultrasound levels referred to in older guidelines, he says, nor should guidelines for occupational ultrasound exposure be applied to exposure in public places.

New guidelines should also account for people who are “long-term guests” in public buildings where ultrasound exposure may be high, such as in schools, hospitals and prisons.

Last year, a study that suggested people exposed to higher levels of noise pollution are more likely to have a bigger waist size.