Monthly Archives: August 2011

Stop! Think for a moment with both your cognitive brain parts

Sometimes in life we are going too fast. We don’t know how to slow down and take a breather. It is like we are trying desperately to be one step ahead of everyone. What we don’t understand is that they are trying the same thing. We go at 100 miles an hour and yet, we are followed by others. The race to succeed never really goes away. You know that wonderful retirement stage where you envision yourself sitting on a rocking chair drinking a tall glass of iced tea looking at the scenery around you from the porch of your house while your great grand children play in the backyard? Well, let’s just say that will never happen.

When a car spins out of control a bystander can often tell how the car might spin but when a person spins out of control, you can never tell anything until the shit hitting the fan has finally had the chance to settle down on some part of the room.

This is what happened to me. No, I didn’t meet with an accident. But, I caught the flu. I was careless enough to play in a river all day long and uninhibitedly walked around in wet clothes. Add to that, a sick friend who exposed me to a possible influenza virus and I am a very sick man. Being sick and having someone fuss around you leaves two things for you to do: Sleep and think. I did the most rational thing a person can do. I slept for 24 hours in 2 days. Rest of the time, I thought about how difficult it must be for people who are invalid for the rest of their lives to deal with it and this brought to my mind a TED talk that I watched way back about a woman who suffered a stroke. Her name is Jill Bolte Taylor. She is quite famous for her book – My Stroke of Insight. She was also on The Oprah Winfrey Show to promote her book.

If you haven’t listened to her TED talks or read her book, this is what she went through.

Jill Taylor was a neuroscientist who worked on schizophrenia (a kind of mental disorder – more on this later, I promise you). In 1996, a blood vessel in her brain exploded in the left half of her brain. It is important to understand that the left hemisphere is an integral part of everyday life. In fact, it is the dominant of the two hemispheres and is responsible for things such as walking, talking, reading, writing, recalling etc. Basically, without the left part of your brain, you will be an infant. That is not a nice thing, I assure you. Diapers and drool all day long!

So, why bring up Jill Taylor and her stroke. I wanted to talk to you about an exciting thing inside your brain. Wait! Make that two exciting things: The left and the right hemispheres. Before you get disappointed, let me assure you, this is one of the best things nature has created. Can you believe that the two parts of our brain process differently? They think about different things, care about different things and in fact come up with different solutions for a single problem. The two parts are connected in the middle through the corpus callosum and this is a medium for connection and contact with each other.

Jill Taylor thinks that the two parts of the brain have different personalities.

Let me give you a few things that the right and left hemispheres do. Our right hemisphere thinks in pictures. It understands different the situation kinaesthetically (smell, feel, hear) and makes a mosaic picture on where we are standing, what we are doing etc. In fact, it is concerned about the present. The “this moment” of my life is what right part understands and cares for.

On the other hand, the left side of the brain is more logical. It is linear in its thinking. It recalls the past, thinks about the future keeping the present mosaic that the right builds up as a base for its thought process. It is detail oriented (sounds like something you find on a CV. Next time you can write, my left part of the brain is my real boss. So, I am more interested in details, futures and not repeating past mistakes). More importantly, our left hemisphere contains the memory for words and language. So, it thinks in language and words (Again, a CV pointer. Are you noting it down somewhere?).

“Did you watch what she said? OMG” did a small voice inside your brain tell you this when you listened to someone on the TV or on the road? That small voice is a weapon created by the left part of the brain not only to give you sane advice but also to make your life miserable with guilt. But, it is also a distinguishing feature. Do you remember the day you recognized that small voice in your mind as yours? No? Because, it has been there always and it is responsible for your self – identification. “I am not like that. I am a better person than that. I am the way I am” all things that can be found on slogan T – shirts as well as the things that the left brain instils in you.

So, the next time you find yourself in a situation where you have that “Aha – moment” think about this: We are not just minions of the world who have opposing thumbs (dexterity, if you will), capacity to stand on two legs (Bipedal) and can feed ourselves. We are the ultimate creatures that nature created. We may not be the fastest or strongest or even the loudest but we are definitely the smartest. Case in point, we don’t have one but two cognitive minds. Power to choose our identity and lead our lives. Think about it: use both parts of the brain this time.

Peace

Avinash

Deadly organism of the fortnight – Chironex fleckeri.

One of the things that I find interesting is how potent the tools some predators use to hunt can be. Call me anthropocentric but those that are lethal even to humans are especially interesting to me. As a result, I’ve decided to blog about one deadly critter every fortnight. This fortnight’s selection is Chironex fleckeri, a box jellyfish that is found in the waters off Australia.

Chironex fleckeri, or the sea wasp

This jellyfish apparently has tentacles up to 3 meters in length (when hunting) trailing behind its cuboidal head (hence the name ‘box jellyfish’ and classification under the Class Cubozoa. These tentacles are laden with nematocysts, or stinging cells, which deliver venom when triggered.

Nematocysts themselves are pretty interesting in how they operate, they have a tube with barbed tips which delivers venom from a venom sac, a trigger hair or a cnidocil and a nucleus, all packed into a capsule with a lid, which is called an operculum.

When the cnidocil brushes against prey, it triggers the opening of the operculum, the venom tube springs out like a whiplash, the barbs penetrate the skin of the prey and the tube delivers venom. That is pretty much the modus operandi of nematocysts

If you’re wondering how single cells like that could penetrate human skin and deliver venom, the answer lies in the sheer speed of it all, for a nematocyst to achieve envenomation takes just 700 nanoseconds, (1 nanosecond = 10 to the power of -9 seconds) and achieves an acceleration of 5,410,000 g, which is 5 million times the acceleration due to gravity, and that is bloody quick.

I suggest you read the paper to find out how this was studied, the link is in the image caption (note – you can also bring up a full-resolution version of the image by right-clicking and selecting ‘view image’)

Now the reason Chironex fleckeri is deadly is not just due to having lots and lots of nematocysts, it has to do with the potency of its venom. The venom has multiple effects – it causes necrosis of the skin, which leads to an intense burning sensation, it is also cardiotoxic, where it paralyses the heart leading to cardiac arrest. While a significant amount of venom is needed for a sting to be lethal, a fatal dose, if delivered, can kill within 4 minutes. It is also neurotoxic and may lead to paralysis of non-cardiac muscles.

You may find relevant information on how Chironex fleckeri venom acts and what measures are used to deal with cases of envenomation from this paper

Further references

[1] A paper on the nature of the compounds found in C.fleckeri venom

[2] There is some evidence for these jellyfish being able to react to different colours differently (they have eye clusters) , that phenomenon is recorded and described in this paper

That is all from me regarding this fortnight’s choice of deadly critters. Next fortnight I will be picking something else.

The immune system – a brief overview

There are a lot of posts in this blog that require at least a minimum awareness of immunology. So, I decided to tell you what immunology really deals with and how you can understand previously discussed topics with this knowledge.

So, what is immunology? Basically, it is studying body’s defence mechanism. It is important to understand this in both healthy as well as diseased conditions because the body has different components “active” in different scenarios.

What are the different things involved in the immune system? Many components of the immune system are actually cellular in nature and not associated with any specific organ but rather are embedded or circulating in various tissues located throughout the body. There are some organs which are responsible for the production of these cells. They include thymus, bone marrow (Bone marrow, the soft tissue in the hollow centre of bones, is the ultimate source of all blood cells, including lymphocytes), spleen, tonsils, lymph vessels, lymph nodes, adenoids etc. The cells are in turn responsible for the production of different kinds of biomolecules (Eg: Antibodies)

The key to a healthy immune system is its remarkable ability to distinguish between the body’s own cells, recognized as “self,” and foreign cells, or “nonself.” The body’s immune defences normally coexist peacefully with cells that carry distinctive “self” marker molecules. But when immune defenders encounter foreign cells or organisms carrying markers that say “nonself,” they quickly launch an attack.

In abnormal situations, the immune system can mistake self for nonself and launch an attack against the body’s own cells or tissues. The result is called an autoimmune disease. Some forms of arthritis and diabetes are autoimmune diseases.

Where are the cells concentrated? Lymph nodes, which are located in many parts of the body, are lymphoid tissues that contain numerous specialized structures.

  • T cells from the thymus concentrate in the paracortex.
  • B cells develop in and around the germinal centers.
  • Plasma cells occur in the medulla.

Lymphocytes can travel throughout the body using the blood vessels. The cells can also travel through a system of lymphatic vessels that closely parallels the body’s veins and arteries.

Cells and fluids are exchanged between blood and lymphatic vessels, enabling the lymphatic system to monitor the body for invading microbes. The lymphatic vessels carry lymph, a clear fluid that bathes the body’s tissues.

The immune system stockpiles a huge arsenal of cells, not only lymphocytes but also cell-devouring phagocytes and their relatives. Some immune cells take on all intruders, whereas others are trained on highly specific targets. To work effectively, most immune cells need the cooperation of their comrades. Sometimes immune cells communicate by direct physical contact, and sometimes they communicate releasing chemical messengers.

Why are we using proteins and cells of the immune system for research purposes? If evolution is so perfect and we are the ultimate answer to all animals, why are we being plagued by so many diseases and disorders?

Unfortunately, we are not the only products of evolution. Viruses, bacteria and other harmful microbes have also had similar treatment from nature and they are equipped with arsenals that have the capacity to evade our immune systems. As for why we need to do research on the immune system, for the simple reason that we will have more information on how to tackle the diseases and disorders that are life threatening.

What kind of research is going on? Scientists are now able to mass-produce immune cell secretions, both antibodies and lymphokines, as well as specialized immune cells. The ready supply of these materials not only has revolutionized the study of the immune system itself but also has had an enormous impact on medicine, agriculture, and industry.

Read about monoclonal antibodies here. Ankur has provided a good description of its use and production.

Research into the delicate checks and balances that control the immune response is increasing knowledge of normal and abnormal immune system functions. Someday it may be possible to treat autoimmune diseases such as systemic lupus erythematosus by suppressing parts of the immune system that are overactive.

Scientists are also devising ways to better understand the human immune system and diseases that affect it. For example, by transplanting immature human immune tissues or immune cells into SCID mice, scientists have created “humanized” mice, a living model of the human immune system. Scientists are manipulating the immune system of humanized SCID mice to discover ways to benefit human health. Humanized mice are also being used in research on transplantation and autoimmune and allergic diseases, and to manufacture molecules that help regulate immune system function and immune tolerance.

In pioneering experiments, scientists are removing cancer-fighting lymphocytes from the cancer patient’s tumor, inserting a gene that boosts the lymphocytes’ ability to make quantities of a natural anticancer product, then growing the restructured cells in quantity in the laboratory. These cells are injected back into the person, where they can seek out the tumor and deliver large doses of the anticancer chemical. This is called cell therapy.

Now that you have enough information for understanding the immune system, you can appreciate all its myriad applications. There are several ways by which the cells, organs and even protein molecules of the immune system can be manipulated for the betterment of the society.

Hope you enjoyed this. If there is something you have difficulty understanding or you would like us to give you information on a specific topic, please don’t hesitate to ask.

Peace

Avi

Diagnosis goes the microfluidics way – A short introduction.

One of the coolest things about molecular biology and the applications thereof is that technology can be developed to handle small amounts of samples for analysis while being extraordinarily sensitive. In previous posts, I have talked about things such as Microarrays and Cantilever Arrays (which are more sensitive and require lower sample volumes for effective functioning) and also about ELISA, which can be used to detect proteins (either antibodies or antigens) by harnessing a reaction where an antigen binds to an antibody. The technology I’m showcasing in this case is an immunosorbent assay and does the same thing as ELISA, but is cheaper, more efficient and does not use enzymes et cetera. It is a microfluidic device.

The device is called the mChip, and is explained in the video that follows.

As little as a microlitre of whole blood is enough to carry out detection of pathogens such as HIV (or the presence of antibodies to it) and the device can be co-opted to handle any other pathogen if so required by modifying what goes in several looping, serpentine regions along the path the sample flows through.

These regions contain, for instance, antigens to which antibodies in the blood sample may bind, a secondary antibody tagged with gold and silver is then added and these will bind to any antibodies in the sample that have already bound to the antigens found in those loops. Excess antibodies can be washed off and excess sample removed (simply by passing it in at one end of the chip and taking it out at the other)

The colouration that the silver imparts can be used for quantitative estimation and to perform diagnosis.

The advantages are that it works with very low quantities of sample, meaning that sample collection is easier (using a drop of blood from a finger prick is easier than withdrawing blood using an intravenously inserted hypodermic needle) and is very quick (and bloody cheap)

The disadvantage, I suspect, could be issues with false positives, but it is solely my intuition at my moment and to see if there is any substance to my suspicion will necessitate large scale field trials.

If you can get past those nasty paywalls, you will be able to find the peer-reviewed research paper that describes the gadget at http://www.nature.com/nm/journal/v17/n8/full/nm.2408.html

That’s all from me this time round.