Older Men’s Sperm May Have Disease-Causing Mutations
There is a new warning for men who are thinking of delaying fatherhood.
Scientists at University of Oxford in the UK have identified a source of some severe disease-causing mutations in sperm-producing tubes inside the testicles of healthy men.
Sperm production starts in puberty, in the seminiferous tubules inside the testicles. A man’s testicles produce millions of sperm and new spermatogonia every day.
At each cell cycle, the DNA in the old spermatogonium is copied into the new cells – destined to be a sperm cell. But every so often, a copy error – a mutation – arises in the DNA, which carries on in new generations of cells.
Many mutations are harmless, but some that occur in the spermatogonia enhance their own chances of propagating forward – they are called “selfish mutations.” It appears that the effect of selfish mutations is to cause spermatogonia to give rise to more than one new spermatogonium at each cell cycle, each carrying the mutation.
As a man ages, and his sperm production undergoes more cell cycles, his sperm contains an increasing proportion of cells with selfish mutations.
The study investigated a rare genetic disease called Apert syndrome that affects the development of the skull and limbs. The disease affects about 1 in 60,000-70,000 babies. It’s caused by new mutations in a gene called FGFR2 that arise spontaneously in the father’s sperm production as he gets older.
The researchers note that all men will develop these mutant growths in their testicles as they age. However, as men are tending to delay fatherhood, it is important to understand the risks.
Sourced from: Medical News Today, As men age, their sperm contains more disease-causing mutations
Published On: Feb 11, 2016
Did Head Injuries Cause Henry VIII’s Erratic Behavior?
“Erratic” may be a charitable adjective in Henry’s case.
Six marriages, two wives beheaded, founding his own Church when the Pope refused to annul his marriage – Henry VIII’s reign was one of constant tumult as his moods swung from one extreme to the other.
Now scientists at Yale University have set forth the theory that repeated head injuries during jousting matches might have transformed an intelligent, even-tempered young man into an impulsive, forgetful king known for his rage and impulsive decisions.
It’s a diagnosis strikingly similar to current ones involving NFL players with chronic traumatic encephalopathy (CTE).
After examining volumes of letters and other historical documents, the researchers concluded that the most plausible explanation for the English monarch’s headaches, insomnia, memory loss, poor impulse control and short temper were that they resulted from jousting and other falls.
Among the documented cases of the monarch’s injuries: In 1524, Henry was dazed when a lance penetrated his helmet during a jousting tournament. The following year, he fell head first into a brook while trying to vault across the water. The incident rendered him unconscious. And, in 1536, he lost consciousness for two hours after a horse fell on him.
“It is intriguing to think that modern European history may have changed forever because of a blow to the head,” said study senior author Dr. Arash Salardini, a behavioral neurologist and co-director of the Yale Memory Clinic.
Sourced from: HealthDay, Head Injuries May Explain Henry VIII’s Erratic Behavior, Study Suggests
Published On: Feb 11, 2016
Why 9 Out of 10 Runners Suffer Injuries
It’s a startling statistic.
Running injuries are so extremely common that some statistics estimate that as many as 90 percent of runners miss training time every year due to injury.
But a new study published in the British Journal of Sports Medicine suggests that being light on your feet could keep most runners healthy.
Past studies have blamed running injuries on everything from excess body weight to modern running shoes to rough pavements. These researchers decided to study those who have run for a long time but had never been hurt. Specifically, they set out to look at pounding, or impact loading, which means the amount of force that we create when we strike the ground. The team recruited 249 experienced female recreational runners, chosen in part because they all struck the ground with their heels when they ran. Most runners are heel strikers, and heel striking is believed by many running experts to cause higher impacts than landing near the middle or front of the foot, possibly contributing to an increased risk of injuries.
During the two years that researchers tracked them, more than 100 of the runners reported sustaining an injury that was serious enough to require medical attention. Another 40 or so reported minor injuries. Remarkably, 21 of the runners not only did not become injured during the two-year study but also had not had a prior injury.
Further investigation revealed that the never-injured runners, as a group, landed far more lightly than those who had been seriously hurt – even when the researchers controlled for running mileage, body weight and other variables.
The study authors advise runners to consciously think about “a soft landing,” or put another way – imagine that you are running over eggshells.
Sourced from: The New York Times, Why We Get Running Injuries (and How to Prevent Them)
Published On: Feb 11, 2016