How do Muscles Know how Much We Weigh?

Extremely overweight people often complain that it is physically hard to move.  Working with animals, scientists may have found a clue to explain that finding.  Normal weight mice show changes in the concentration of a particular muscle protein when they're fitted with heavy vests.  The increase in troponin T allows muscles to contract more strongly.

In obese mice, the gene for troponin T seemed to malfunction, and levels of muscle proteins involved in contraction were not increased.  This relative weakness can make moving more difficult, eventually leading to animals cannot move at all.

The bigger mystery, how muscles know how much you weigh and adjust their composition accordingly is still unsolved.  Troponin T may be one part of the puzzle, but clearly not the only one.

Although this research was performed in animals, it may have implications for humans.  Extremely overweight people may do better initially with exercises that do not require them to bear their whole weight, such as swimming, when compared to running.


NY Times Article

Kim Kardashian has Psoriasis

Psoriasis is a common skin disease.  The most common symptoms include red patches of skin covered with silvery scales and dry cracked skin that bleeds easily. Mild cases may be a nuisance, more severe cases can be disfiguring and disabling, especially if joints are involved in arthritis.  Psoriasis is a chronic disease, with periods of flare ups and remissions.

Heredity and environment play a role in development of the disease.  In Kim's case, her mother has had psoriasis for years.  Precise causes are not known.  The immune system appears to recognize skin cells as non-self, and attacks them.  This leads to excess skin cell growth and further activation of the immune system.

Treatment depends on the severity of the disease and can include creams that limit inflammation, vitamin D analogues and others. To make skin look and feel better, using mild soap and warm not hot water for soaking, covering affected skin overnight and small amounts of sunlight can help.

CNN Article

Rare Aging Disease May Provide Insight into Common Cellular Process

Progeria is a rare disease characterized by accelerated aging, beginning at birth.  It can be due to a de novo mutation of a single nucleotide within a gene on chromosome 1, or autosomal dominant or recessive inheritance.  This leads to the production of mutated progerin protein.  Mutated protein is difficult to clear from the cell, and causes misshapen and dysfunctional nuclei.

A recent study suggested that rapamycin, an immune suppression drug, may activate the cell's waste removal system and lead to better cell function.  Human trials are being discussed.

Accumulation of waste products is a feature of other human diseases, such as Alzheimer's and Parkinson's.  Part of the excitement around the discovery of rapamycin's effect is the possibility that it may be helpful in these more common diseases.

Links:
CNN Article on Progeria and Rapamycin
OMIM reference to progeria

What's the Purpose of This Blog?

I've started this blog to address the learning objective of connecting the course material to life.  Each post will contain

• a summary of a current article (within the last 3 months) from the popular press
• the link to that article
• a comment area

Each student will be expected to post a comment to 3 blog posts during the semester.