Laptops and cancer...

So I decided to do a slightly interesting post for my last blog. Recently I read an article claiming that laptop use can lead to testicular cancer (I heavily doubted its validity, but thought it interesting). Testicular cancer is fairly rare, but is the most common form of cancer in 15 to 34 year olds (this subset of the population rarely gets any cancer). Much of the supposed "research" that has been done is merely interviewing young business professionals who use laptops frequently during long flights. Of course, the ones interviewed are in the upper range of the most effected population range. While searching on the internet for this topic I stumbled upon this article which mentions hematologist and oncologist Timothy M. Kuzel of Northwestern's Feinberg School of Medicine. According to the article Kunzel states that he felt that any relationship between testicular cancer is highly debatable: "We’re not seeing an epidemic of 50-year-old businessmen with testicular cancer." That is to say one would also expect elevated levels of all laptop users. There aren't.

So as to whether we men should be worried about holding our laptops away from, ahem, ourselves when we use them, the answer, like that of cell phone usage and brain tumours is no. This area should definitely be watched as carcinogens and radioactivity may act slowly depending on dosage, but for the moment, I am not particularly worried.

Blinking neurons

Perhaps I am a little too nerdy, however, when I read this article from the Max Planck Society. Anyone who has a biology lab has probably performed a genetic transformation lab. Essentially a plasmid (circular strand of DNA) is transferred from one organism (the standard to use in bio classes is called the PUC8 plasmid) into a bacteria which has been heatshocked. Inserting the plasmid will change the bacteria so that it expresses proteins that grant it such properties as antibiotic resistance and the ability to break down lactose into galactose and glucose (this latter property is used to identify the bacteria that take up the plasmid, the breakdown creates a blue product). In addition proteins such as green flourescent protein (GFP) plasmids are added for the same reason (GFP is actually common, look for the green GloFish next time you're at a pet store). These techniques are useful as they can allow macroscopic visualization of microscopic events.

The specific type of GFP (along with another unnamed flourescent protein) used for this study is known as "Cameleon" and it is a GFP molecule that is activated by calcium. Essentially calcium binds to the protein and causes the flourescent molecules to approach each other and change color. As neurons are involved in calcium signaling, the application of cameleon to neurons will allow neuroscientists to observe neuronal signaling in realtime without microelectrodes for stimulation and voltage measuring. When a neuron is activated, calcium concentrations generally raise and the color of the neuron will alter.

According to the study:

These new advances, using light to study the brain, provide us with a unique opportunity to investigate how memories are formed and lost and, furthermore, when and where nerve cell activity patterns become altered as in the case of aging and also in neurological diseases such as Alzheimer’s disease, Parkinson’s disease and schizophrenia.

This is a very unique new technique with diverse applications and it will be most interesting what may discovered with its use in time.

More on vitamin D

Last week I spoke of some recent benefits mentioned for consumption of milk and the ill effects of vitamin D deficiency along with several alternate sources of vitamin D. While scanning Eurekalert.org's science news service I came across yet another article concerning the ill effects of deficient levels of vitamin D on patients suffering from multiple sclerosis (MS). MS is a debilitating neuromuscular-immune disorder which involves immune cells attacking the body's own oligodendrocytes (also known as Schwnn cells when located in the peripheral nervous system) which possess the primary function of insulating axons. This causes the loss of signal from the brain to the muscle.

According to a University of Buffalo study published in the American Academy of Neurology, "(l)ow vitamin D levels may be associated with more advanced physical disability and cognitive impairment in persons with multiple sclerosis." The 236 participants' blood serum for total vitamin D (D2 and D3) along with active vitamin D byproducts. According to the study "(r)esults showed that only seven percent of persons with secondary-progressive MS showed sufficient vitamin D, compared to 18.3 percent of patients with the less severe relapsing-remitting type." This indicates that there is a possible correlation between vitamin D levels and severity of neurodegeneration in MS. When controlling for both season (Winter is associated with lower levels of vitamin D) and depression (which is also associated with lowered vitamin D levels), this relationship still held true.

Little is currently known about vitamin D's relation to cognitive development or degeneration. What is known is that vitamin D levels are associated with increased risk for MS and that low levels may be implicated in worse prognosis for MS. As I have stated many times before, we do not know enough about these severe neurological diseases and much work is yet to be done in order to prevent and fine treatments for these conditions.

Artificial scents and flavors

I just exited from my final lab in Organic Chemistry II (with some elation I must add) in which I was to identify one of four unknown organic compounds using a slew of laboratory procedures. I chose the first compound and proceeded to waft the scent of the compound (this really is a bad idea considering many organic compounds can be highly toxic and/or carcinogenic but it is very quick for identification of a class of compounds). I knew that I had picked a relatively simple compound to identify as it smelled (at least to me) like licorice flavoring in taffy or jelly beans and peppermint (which is a most delicious scent combination by the way).

Whenever we purchase orange soda, perfume or cologne the flavors and scents that we admire are not compounds that are necessarily found in fruits or musk, but rather organic chemicals. Specifically most of these are derived from aptly named aromatic compounds typically derived from benzine, the most studied of aromatics. For instance, my compound was determined to be ethyl benzoate which is a flavoring and scent most often associated with Ylang Ylang and tobacco essences. In wine alone over 200 flavor components are due to organic aromatics, in simple coffee over 800 are present. The interactions of these compounds with taste receptors give rise to the highly complex sensations of taste associated with these beverages.

Perhaps our Organic classes would be more beneficial to the student if they aided theory with practical and intriguing uses and qualities of aromatic compounds. I for one find it more interesting that such simple variations on a simple molecule like benzine can create so many diverse scents and flavors. I most certainly will be able to identify an aromatic ester by its smell.

Drink more milk and enoy the summer

Vitamin D is a group of fat-soluble secosteroids (which is similar in structure to a steroid but involves the breaking of one of a steroids cyclic rings) that are commonly found in fish, eggs and milk. In addition sunlight helps facilitate synthesis in the human body which is thought to be enough to prevent deficiencies. However, fewer individuals are meeting the necessary allotment of time outside to aid vitamin D synthesis and deficiency is becoming a potential problem. According to the National Institutes of Health Dietary Supplement fact sheet the minimum daily requirement for Vitamin D intake is 200 IU (5 mcg), several dietary guidelines recommend 400 IU (10 mcg). For reference, to meet these guidelines 4 glasses of non-fat or low-fat milk would need to be consumed (more of higher fat content milk) or it is suggested by the Mayo clinic that merely 10 minutes in direct sunlight would suffice to prevent deficiency. One would assume that these requirements would be easy to meet (I should mention that one must be careful with vitamin D intake, as I stated earlier it is fat-soluble - it can easily be built up to toxic levels if one is not careful and consumes too many sources of it).

Apparently not. A study described on Eurekalert's online science news website stated that Vitamin D intake levels are so startingly low that "current deficiency levels prompted the American Academy of Pediatrics to double the vitamin D recommendations for children and teens." Half of adolescents, according to the study, are deficient in Vitamin D. It seems to be well-known that Vitamin D and calcium intake will help prevent osteoporosis and other bone problems (primarily in women), but there are other benefits of Vitamin D that are quite beneficial. Studies have correlated adequate Vitamin D intake levels with lower levels of diabetes, hypertension, heart disease and certain cancers. In addition the immune system also benefits from adequate Vitamin D levels (so if you want to prevent catching a bacterial infection, you should perhaps opt for some yogurt over antibacterial soaps).

This being said I think I think it is a pretty simple task to drink another glass of milk per day and spend a few minutes outside. It most certainly will pay off later down the road when we are at risk for all manner of chronic diseases.

Stroke after cardiac bypass

I was perusing Eurkealert.org and came across this interesting study relating cardiac bypass procedures to stroke.

A cardiac bypass involves using existing blood vessels from the patient in order to build an alternate route for blood to flow through around a blockage which are caused primarily by the buildup of fat and cholesterol. In order to prevent organ damage in the patient undergoing a bypass, the body is cooled and subsequently been rewarmed. For years approximately 5% of cardiac bypass patients wake up post surgery with a significant loss of motor activity or speech; to this date few explanations why this correlation of bypass surgery with stroke would occur exist.

Stroke is caused by a disruption to the blood supply of the brain restricting both glucose and oxygen supplies. The brain requires much of the oxygen and glucose in the body in order to function and a disruption of blood flow robs the brain of its nourishment causing cellular death. A recent study from Johns Hopkins may have pinpointed this correlation between stroke and cardiac bypass surgery to the procedure of cooling and rewarming the body in order to prevent organ damage. According to the study blood flow and pressure were recorded for "127 patients undergoing standard, lengthy cardiac bypass surgery during which they spent two hours on a heart-lung machine that circulated their blood for them" and "(e)leven patients undergoing shorter bypass operations were kept at normal body temperature throughout and served as a control group." Of the 127 test subjects 7 suffered from stroke and 1 suffered from a transient ischemic attack which is considered a harbinger for future stroke. None of the control groups suffered an attack of any kind.

While this study does suffer from a minuscule control group, it does help point that the rewarming technique may somehow interfere with the autoregulation mechanism that helps to prevent damage to the brain from blood pressure fluctuation. Currently the research team for the study is developing a near-infrared monitoring device for cardiac bypass surgeries to display blood flow in real-time allowing surgeons to alter blood pressure in order to protect the brain from risk of stroke.

Chloride channels and epilepsy

According to the Mayo Clinic, epilepsy is "a disorder that results from the generation of electrical signals inside the brain, causing recurring seizures." The symptoms of seizures vary drastically, some patients may simply blankly stare for a few moments while others may convulse. In order for a diagnosis of epilepsy, one lone seizure is not sufficient. Statistically speaking, approximately 1 person out of 100 will experience at least one seizure in their lifetime and for 7 out of 10 persons experiencing multiple seizures (epilepsy), no cause may be found. It is clear that due to the risk of death and injury from seizures due to drowning, falling, burning, car accidents and complications in pregnancy, much work must be done to determine specific causes of epilepsy (it is currently believed that oxygen starvation during the natal and prenatal periods may contribute as well as simple differences in brain structure).

A new study by the Max Planck Institute of Neurobiology (I find it interesting that many biomedical facilities were named after physicists, not that this is incorrect as all biological processes seem to arise from conglomerations of quantum physical interactions; still it seems more appropriate for an institute of neurobiology to be named in honor of a neurologist, neuroscientist, psychiatrist or psychologist) has studied the physiology of the chloride channel ClC-2 which has been implicated in a relation to epilepsy and seizures. A prevailing theory of the function of the Clc-2 channel is that as the amount of functioning ClC-2 channels decrease, the more likely the neuron will be activated (its excitability increases due to the greater intracellular concentration of negatively charged chloride ions. However in mice with genetically malformed ClC-2 channels were no more susceptible to seizures than the healthy controls. More confusing is that despite this lack of susceptibility of mice with dysfunctional ClC-2 channels, the neurons lacking the channels were still more excitable than the normal neurons. The answer to this conundrum is actually quite elegant; as the neurons lack ClC-2 on excitatory neurons (which can signal other neurons and lead to actions, or seizures), so do inhibitory neurons (which will lead to nonaction, or help prevent seizures).

It is proposed in this study that while ClC-2 channel presence is implicated in excitability, it may still be implicated in epilepsy. Protein channels may be opened or closed due to presence of chemicals that both naturally (neurotransmitters, hormones , etc.) and unnaturally (medications, drugs, etc.) occur in the brain. It is proposed that the neurons can alter the structure of the ClC-2 neuron in order to alter its excitability (essentially a normal neuron with mitigating factors can act as though it was a dysfunctional neuron as compared to the study described above).

Clearly, we know little about the neurobiological basis of epilepsy and some of what we have discovered is complex and confusing. We need to carry out more research both on the cellular, molecular and clinical scales in order to determine the pathophysiology of these neurological diseases. Neuroscience is a young field, and as V. S. Ramachandran describes, every science must enter into an experimental phase before it can answer its primary question. Neuroscience, it appears is still in it's experimental stage.