Tonic immobility during rape associated with increased risk of PTSD

Active resistance is often considered to be the “normal” reaction during rape, but a Swedish study has found that most victims may experience a state of involuntary paralysis, called tonic immobility, during rape. Tonic immobility was also associated with subsequent post-traumatic stress disorder (PTSD) and severe depression after rape. The findings, published in Acta Obstetricia et Gynecologica Scandinavica, indicate that for health care follow-up and legal matters, tonic immobility should be assessed in all sexual assault victims. Tonic immobility in animals is considered an evolutionary adaptive defensive reaction to a predatory attack when resistance is not possible and other resources are not available. Little is known about tonic immobility in humans, however. The Swedish researchers assessed tonic immobility at the time of assault in 298 women who had visited the Emergency Clinic for Rape Victims in Stockholm within 1 month of a sexual assault. After 6 months, 189 women were assessed for the development of PTSD and depression. Of the 298 women, 70% reported significant tonic immobility and 48% reported extreme tonic immobility during the assault. Among the 189 women who completed the 6-month assessment, 38.1% had developed PTSD and 22.2% had developed severe depression. Tonic immobility was associated with a 2.75-times increased risk of developing PTSD and a 3.42-times increased risk of developing severe depression. Prior trauma and a history of psychiatric treatment were also linked with tonic immobility.

Excessive exercise may damage the gut

A review of published evidence led by Dr Ricardo Costa from Monash University, has found that excessive exercise – defined as ≥ 2 hours at 60% VO2max – may lead to acute or chronic gut problems. Published in Alimentary Pharmacology and Therapeutics, the review found that with increasing intensity and duration of exercise, there was a proportional increased risk of gut damage and impaired gut function. Specifically, the cells of the intestine are injured and the gut becomes more leaky, allowing pathogenic endotoxins normally present and isolated to the intestine to pass into the bloodstream. This scenario of “exercise-induced gastrointestinal syndrome” may lead to acute or chronic health complications. Exercise stress of ≥ 2 hours at 60% VO2max appeared to be the threshold whereby significant gut disturbances arose, irrespective of an individual’s fitness status. Running and exercising in hot ambient temperatures appeared to exacerbate the gut disturbances. The review also found that for patients who have irritable bowel syndrome or inflammatory bowel disease, low to moderate physical activity may be beneficial. The health implications of more strenuous exercise have not been researched, but are likely to be detrimental for such patients.

New hope for women with BRCA1 breast cancers

Australian researchers from the Walter and Eliza Hall Institute of Medical Research (WEHI) and the Peter MacCallum Cancer Centre have found a new way to use immunotherapy to treat aggressive triple negative breast cancers arising in women with BRCA1 gene mutations. In a laboratory-based study published in Science Translational Medicine, the researchers showed that combining two immunotherapies – anti-PD1 and anti-CTLA4 – with chemotherapy halted the growth of BRCA1-related tumours and significantly improved survival in laboratory models. Some cancer cells survive by hijacking and “switching off” immune cells that would otherwise destroy the tumours. Anti-PD1 and anti-CTLA4 immunotherapies are so-called “immune checkpoint inhibitors” that release the brakes on critical immune cells, enabling them to attack the tumour. Dr Daniel Gray, from WEHI, said that previous research had shown that immunotherapy was particularly effective at treating tumours that had accumulated many mutations. “BRCA1-related triple negative breast cancers have some of the most ‘chaotic’ genomes, and we see many immune cells accumulate in and around the tumour,” Dr Gray said. “This suggests that the immune cells can readily detect that something is awry, but they aren’t able to respond properly, because they have been disabled by tumour cells. We showed that a combination of anti-PD1 and anti-CTLA4 therapies restored their ability to attack and kill triple negative breast tumour cells, and very effectively control tumour growth.” Associate Professor Loi, head of breast cancer clinical trials research at Peter MacCallum Cancer Centre and for the Parkville precinct, said work was already underway to translate these important findings from laboratory models of breast cancer into a clinical trial for women with the disease.

Fructose healthier than sucrose or glucose

Fruit-based sugar may be healthier than sucrose or glucose, according to Australian research from the University of Canberra, published in the American Journal of Clinical Nutrition. Researchers from the University’s Health Research Institute examined the short and long term effects of swapping sucrose or glucose, for fructose, the sugar found in many fruits, vegetables and honey. They found that blood glucose and insulin levels were lower after consuming food or drinks that contained fructose, compared with those with sucrose or glucose. Senior author of the report Dr Kerry Mills said that in the short term study, the reduction in blood glucose was far greater in people who were overweight or had diabetes than in people with normal blood glucose levels. “The sharp rise in blood glucose after eating glucose and sucrose is a risk factor for diabetes. Fructose, on the other hand, has to be converted by the liver before it can affect glucose concentrations in the blood,” Dr Mills said. “Because this conversion takes time, it’s impossible for the body to receive the near-instant sugar hit we get from sucrose or glucose. This reduces blood glucose levels, which is particularly important for people with diabetes, who must monitor and control these levels.” When looking at the longer term effects of swapping types of sugar, the study also found a reduction in blood glucose levels; however, the difference was not as dramatic over time. Dr Mills said the results show that healthier choices when it comes to sugar intake may make a difference for people with diabetes, but fructose should not be seen as “some kind of health food”. “High sugar intakes may lead to health problems, and everyone should be trying to cut out sweet treats. But if sugar consumption can’t be avoided, it is probably better to choose products with fructose over other types of sugar,” she said.


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