Fat used to grow blood vessels
Excess fat may have a purpose after all. Adult stem cells extracted during liposuction can be used to grow healthy new blood vessels in the lab for use in heart bypass surgery and other procedures. Current grafts - from vessels elsewhere in the body or artificially created - carry a risk of clotting, being rejected or otherwise failing to function normally, says lead study author Matthias Nollert, from the University of Oklahoma. 'Our engineered blood vessels have good mechanical properties and we believe they will contract normally when exposed to hormones. They also appear to prevent the accumulation of blood platelets - a component in blood that causes arteries to narrow.' In the study, stem cells derived from fat were turned into smooth muscle cells, then 'seeded' onto a collagen membrane. As the cells multiplied, they were rolled into tubes the diameter of small blood vessels. Within four weeks, they grew into usable vessels. The researchers hope to have a working prototype to test on animals within six months.
New weapon in battle of the bulge
Another day, another drug for the obesity battle. This new drug aids weight loss by increasing sensitivity to the hormone leptin, a natural appetite suppressant found in the body. Leptin supplements alone have not been effective at weight reduction because it's believed the body has been densensitised to the hormone. It's not entirely clear why this happens, but cannabinoid receptors, which mediate the feelings of hunger produced by marijuana and naturally occurring cannabinoids in the body, are thought to be involved. In a study published last week in the journal Cell Metabolism, scientists tested in obese mice a new compound that targets a particular cannabinoid receptor. The compound suppressed the appetite of the mice, caused weight loss and even improved metabolic health, in part by making mice sensitive to leptin again. Importantly, the mice did not show signs of anxiety or other behavioural side effects that previous anti-obesity drugs targeting the receptor had.
Versatility sets man apart from beasts
A light-hearted comparison of the extraordinary athleticism of humans and animals was published in the Veterinary Record last week ahead of the London Olympics. In his study, Craig Sharp, from the Centre for Sports Medicine and Human Performance at Brunel University, notes that humans can run at a maximum speed of 37.6 km/h. Usain Bolt (pictured) runs 100 metres in 9.58 seconds, but a cheetah (maximum speed 104 km/h) does it in 5.8 seconds. An endurance horse can run a full marathon in one hour, 18 minutes and 29 seconds, compared with Patrick Makau Musyoki's two hours, three minutes and 38 seconds record. In the long jump, a red kangaroo can leap 12.8 metres, compared to Mike Powell's 8.95 metres. When it comes to power, the tiny hummingbird can manage 200 watts per kg; cycling world champion Mark Cavendish puts out a maximum 23 watts per kg during a sprint. But no single species matches the physical versatility of human beings, Sharp concludes, and that is what the Games are designed to display to best effect.
Yoga strikes a balance in stroke patients
Yoga can improve motor function, balance, independence, confidence and quality of life for stroke survivors who no longer get rehabilitative care. The study, published in the American Heart Association journal Stroke, involved 47 participants, aged up to 90 or more, and about 75 per cent of them were male veterans. All had had a stroke at least six months earlier and had to be able to stand on their own at the study's outset. They were divided into three groups: twice-weekly group yoga for eight weeks; a 'yoga-plus' group, which did group yoga and listened to a relaxation recording at least three times a week; and a usual medical care group that did no rehabilitation. The yoga classes, taught by a registered yoga therapist, included modified yoga postures, relaxation and meditation, and got progressively tougher. Compared with the control group, those who completed yoga or yoga-plus significantly improved their balance. The yoga patients' mindsets about their disability also improved.