BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: Alzheimer’s (Page 2 of 2)

Herbal Essences

An exciting new study at the St. Louis University Medical School, has gave way to a new theory regarding the prevention of Alzheimer’s Disease. The geriatric researcher, Dr. Susan Farr Ph.D, disclosed at Neuroscience 2013, that extracts of spearmint and rosemary can “reduce deficits caused by mild cognitive impairment, which can be a precursor to Alzheimer’s disease,”.

The research was conducted on an animal model, so there is no conclusive human evidence yet. But Dr. Farr’s results seem promising in that her tests using an “antioxidant-based ingredient” made from spearmint extract and two different concentrations of a similar antioxidant made from rosemary extract on mice that have age-related cognitive decline.

Farr found that the higher dose rosemary extract compound had the most impact in increasing memory and learning in three tested behaviors. The lower concentration rosemary extract improved memory in two of the behavioral tests, as did the compound made from spearmint extract.

Her research also found that the introduction of these extracts to the subjects’ systems decreased oxidative stress, a “hallmark of age-related decline” in the cerebrum, the learning and memory center of the brain.

As Dr. Farr continues her promising research, are you going to find yourself chewing more spearmint gum?

Identical but Not the Same

 

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After studying genetically inherited traits and diseases it could be easy to assume that genes determine everything about us. While it is true that colorblindness is a sex-linked trait – there is certainly more to the story.

Monozygotic “identical” twins are genetically identical, so they should be the same in all ways shouldn’t they?

Why, then, does one twin get early onset Alzheimer’s disease and the other “identical” twin doesn’t? The same is true for height, autism, and cancer. Although, when one twin has a disorder the other is more likely to get the disease also, that is not always the case.

In the January edition of National Geographic, author Peter Miller discusses the newest theories about how genes, environoment and epigenetics affect our life (and the end of it).

Twins offer scientists a unique opportunity to study how genetically identical people differ. Basically, that means scientists can study how things other than genes affect human development and lifespan. Already, scientists have found that a persons height is only 80% determined by genetics because the heights of “identical” twins differ by about .o8 on average. Using IQ tests, scientists have nearly disproved John Locke’s Tabula Rasa or blank slate theory (the idea that children are born with a blank mind that is either stimulated – (and made intelligent) – or not –  (kept unintelligent)). Specifically, scientists studied twins who had been separated at birth and adopted into different families. In this way, scientists have found that intelligence  is about 75% controlled by genetics.

So that leads to the question, what is it besides genes that affects us humans so drastically?

Environment has something to do with our differences. However, that cannot be the whole story. “The Jim Twins” as they are called in the twin science community, were studied in the 1870’s. They were adopted into different families where both boys were named Jim. Then went on to have the same jobs, marry wives of the same name (two Lynda’s first then two Betty’s), enjoy the same hobbies, enjoy the same brand of cigarette and beer, name their sons James Allan and James Alan… the list goes on. These two lived very similar lives, yet they grew up in very different environments. If environment isn’t the only factor in creating difference then what is?

Scientists have recently come to believe that epigenetics plays a significant role in our lives. Epigenetics (site 2) can be seen as the meshing of environment and DNA. In the words of author Peter Miller “If you think of our DNA as an immense piano keyboard and our genes as keys – each key seach key symbolizing a segment of DNA respinsible  for a particulare note or trait, and all the keys combining to make us who we are – then epigenetic prcesses determine when an how each key can be struck changing the tune.”  Environmental changes do have some impact.  When a pregnant mouse is put under stress during the pregnancy it can create changes in the fetus that lead to abnormal behavior as the rodent grows into adulthood.

However, scarily enough, many epigenetic changes appear to occur randomly (thus creating a probelm for the organized nature/nurture theory). Currently work is being done studying DNA methylation, which is known to make the expression of genes weaker or stronger. Specifically, Andrew Feinburg, director of the Center for Epigenetics at Johns Hopkins School of Medicine, is working to find how DNA methylation relates to autism. Currently, he is using scanners and computers to search samples of DNA from autistic twins who have the disease in varying degrees. He is looking to compare how and why

the genes are expressed differently.

In the end, all we know is that there is more to our future than our genes can tell us. Yes, our genes play a huge role in who we are as people – in terms of appearance, character, intelligence and more – but there are some variables that our environment and epigenetics control.

Main Article: Miller, Peter. “A Thing or Two About Twins.” National Geographic. Jan 2012: 38-65. Print.

Don’t forget your sleep

Photo Credit: Me

Let’s face it there are many nights when we don’t get the sleep we need for some reason or other.  Not getting the recommended eight hours of sleep is pretty much the norm for students, but according to a new study this lack of sleep could really be hurting us later on.  This new study found that disrupted sleep appears to be associated with the build-up of amyloid plaques, which are a known to be a hallmarks of Alzheimer’s disease, in the brains of people who did not yet have any memory problems.

The author of the study Yo-El Ju, who works with Washington University School of Medicine conducted the study by testing the sleep patterns of one hundred people, ages 45 to 80, who were free of dementia.  Half of this group had a family history of Alzheimer’s.  Sleep diaries and questionnaires were used to learn about the patients sleeping habits as well as a device placed on the participants for two weeks to measure sleep.

The study found that 25% of the participants had evidence of amyloid plaques, which are known to be able to show up years before symptoms of Alzheimer’s appear.  Most of these people spend an average of eight hours in bed, but only 6.5 hours asleep due to waking up at night.  The study found that people who were waking up more than five times an hour were more likely to have the amyloid plaque build-up than the people who didn’t wake up much at all.  The study also said that people who slept less efficiently were more likely to have markers of early stage Alzheimer’s disease.  Dr.Ju says it will take more time and data to fully understand the link, but I think for now it is safe to say that sometimes we should put our homework down and get to sleep.

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