The process in which bone is able to inhibit resorption and increase formation is initiated by a process called mechanotransduction. This is an extremely complex process involving numerous mechanisms working intimately together to create a cellular response from a biophysical one. This biophysical force is generated by external mechanical stressors— via weight-baring movement— resulting in bone deformation. This bone deformation typically takes place three ways: by a bending, sheering or compression force. A bending force will create a complimentary compression and tension stress relative to the direction of force. When compressed, the bone will undergo a biaxial strain in which it decreases in size vertically, however, expands horizontally—much likesqueezing a marshmallow. Although bone responds differently to both forces, they each create a fluid disturbance within the bone cortex . This fluid disturbance creates a sheer stress on osteocytes— cells located within the bone— which then elicit the networking activity of cellular responsible needed to make osteoblasts.Osteoblasts are essentially what is responsible for bone formation; it does so by producing the bone matrix which then gets mineralized.
Here is a brief video animating the involved process responsible for bone homeostasis.
What the…? Pronounced mezen-kïm-al, these are human stem cells that have this magnificent and cosmic ability to form different kinds of cells in the body — muscle, bone, neural, fat and more— by assisting in the differentiation of other progenitor cells.
Potential. Needless to say, the potential of these multi-purpose cells are shifting the paradigm of medical treatment as we know it. How? By harvesting these stem cells—from ones own marrow or unrelated donor— and then injecting them into the site of injury of a damaged heart, doctors like Roberto Bolli have seen a significant improvement in cardiac function compared to those who’ve just received standard care.
The not-so-bad news. It is not a treatment option as of yet and is still in its infancy.
Purpose of the article. To show how immensely complex and miraculous mammalian biology can be, right down to its basic unit of function.
What are telomeres? Telomeres are the end caps of the chromosomes that contain the repeating DNA sequence that makes us who we are—genetically speaking. They are often compared to the tips of our shoelaces.
What role do they play? Telomeres preserve the integrity of the genome. Essentially, their role is to prevent the chromosome from losing the base pairs in the DNA sequence, which could subsequently result in biological abnormalities such as cancer.
Size matters? As cells divide, for proper biological maintenance as we age, the telomeres get shorter and shorter over time, which results in the loss of base pairs. The shorter the telomere gets the more susceptible it becomes to things such as gene mutation or even cell death death (which in some cases is completely normal). In fact, it is suggested that the length of the telomere could serve as a better marker for the biological effects of aging rather than ones chronological age per se. In laymen’s terms: the longer the telomere, the lesser risk of developing age related diseases and vice-versa.
Telomerase. Telomerase is the enzyme responsible for the elongation of the telomere. As one might surmise, the answer for quelling the aging process would simply mean more telomerase, right? Not necessarily. In fact, there are instances where we would want to decrease our cells ability to elongate the telomeres. One particular instance would be cancer cells. Cancer cells are these super intelligent, self-sufficient cells that have no anti-proliferative properties; they generate their own growth signals and keep dividing and dividing until you have what we know as a tumor. It turns out that over 90% of different cancers have this telomerase enzyme, which would prevent cellular apoptosis (by not allowing the shortening of the telomere).
The good news. While there are no clinical interventions as of yet that could make telomeres longer, it could have some clinical implications. If a physician knows that an individual has short telomeres they could make different decisions in regards to their care.
More good news. It turns out that our behavioral factors play an important role in the size of our telomeres; i.e. exercise,sleep patterns and nutrition. Studies assessing dietary patterns and telomere length found that processed meat consumption was associated with shorter telomere length, while vegetables were associated with longer telomere length. Some recent studies show that exercise has a potentially favorable effect on telomere length as well.The results of a pilot study done at the Norwegian University of Science and Technology suggested that VO2max is positively associated with telomere length, meaning that long-term endurance training could play an important role in muscle telomere length in aging adults. Exercise has also been shown to be a powerful buffer against the shortening of telomere size due to the psychological stress we tend to encounter in our everyday lives.
The conventional pizza you buy, whether it be in the pizza shop downtown or a frozen pizza from A&P, has two major components to them. When combined, these two components wreak havoc on any pre-summer dietary endeavor you may have (unless of course it’s gaining weight).
These two major components? FAT & SIMPLE CARBOHYDRATES.
How does this happen?
First, eating simple carbohydrates spike your insulin levels. When our insulin levels spike it down regulates a hormone called hormone sensitive lipase (HSL). HSL is responsible for facilitating free fatty acids (FFA) out of adipocytes (fat cells) and into the blood stream in order for us to utilize them as energy. The more FFA removes = a decrease in adipocyte size = weight loss!
Second, a FFA is one of three FFA attached to a glycerol backbone (ALPHA-GLYCEROL PHOSPHATE).These are called triglycerides and these are what make a fat cell. The funny thing is that this glycerol backebone is a by-product of carbohydrate metabolism (breakdown of carbs). The more carbohydrates we eat, the more these glycerol molecules are created.
—-NOTE: Our bodies are in a constant state of flux where we burn fat and carbohydrates at rest and low intensity exercise so please don’t think eating carbohydrates will make you fat. It won’t…kinda.—-
So now, when we eat pizza, not only are we down regulating HSL BUT we are also forming all of the glycerol backbones for these fat molecules to bind to!
So after reading this, any preconceived notion you may have about pizza being “good for you” because it has “everything” in a single slice yadda, yadda yadda, should be tossed out of window. Thanks Dr. Jason Sawyer!
Read “The Textbook of Medical Physiology” by Guyton & Hall
It is certainly not the government’s role to dictate or monitor what people eat and how much they move. However, it is the government’s role to enact laws, regulations, and policies that encourage a healthy society. It is also its role to be direct and straightforward, with facts about our current health, the associated costs, and the dire predictions for the future health of our society. Simply stated, we are not built to sustain a healthy body when we are living increasingly sedentary lifestyles, eating processed garbage at an alarming rate, and indeed becoming a fast food nation addicted to high calorie, nutrition-poor foods
The circle is the cell’s nucleus as the protein moves in, and the dark spots are where the protein is blocked. The smiley face doesn’t surprise me; we’re hardwired to see faces and familiar shapes everywhere we look (click the tag marked “pareidolia” — the psych term for this — under this post to see lots of examples). Heck, I spotted one in a supernova once…
And I certainly hope this research yields insight into how to fight cancer. I’d love to see that smirk wiped off that nucleus’s face.
The Harvard School of Public Health sent a strong message to the United States Department of Agriculture (USDA) and nutrition experts everywhere with the recent release of its “Healthy Eating Plate” food guide. The university was responding to the USDA’s new MyPlate guide for healthy eating, which replaced the outdated and misguided food pyramid.
Harvard’s nutrition experts did not pull punches, declaring that the university’s food guide was based on sound nutrition research and more importantly, not influenced by food industry lobbyists. The greatest evidence of its research focus is the absence of dairy products from the “Healthy Eating Plate” based on Harvard’s assessment that “…high intake can increase the risk of prostate cancer and possibly ovarian cancer.” The Harvard experts also referred to the high levels of saturated fat in most dairy products and suggested that collards, bok choy, fortified soy milk, and baked beans are safer choices than dairy for obtaining calcium, as are high quality supplements.
Kudos to Harvard for promoting greater consumption of vegetables and fruits, as well as healthier protein options such as fish, beans or nuts. And kudos to Harvard for ignoring the lobbyists and showing the USDA what healthy eating is all about.
While 47 percent of Americans say they’d like restaurants to offer healthier items like salads and baked potatoes, only 23 percent tend to order those foods, according to a survey last year by food research firm Technomic.