Monday 27 May 2013

Post 101


Non-medic friend: “Hey, how was your day?”
CMM: “Oh, yeah it was pretty good…had class all day though.”
Non-medic: “I heard that medical students dissect rats…isn’t that really gross??”
CMM: “Well…erm….we don’t dissect rats actually….we dissect other stuff.”
Non-medic: “What do you dissect then?”
CMM: “Uhhh..people.”
*cue freak out from non-medic, with much proclaiming of “urghghghgh how could you do that?”, “omggggggg I’m gonna be sick?!” etc.*
The medical school that I attend (which shall remain anonymous in case the GMC decide to slay me for anything I may say in the future) uses cadaveric dissection as a way to teach anatomy, alongside lectures obviously.  We dissect from for a considerable amount of time each week, starting in the very first week of first year.
And yes, it was and is really pretty gross.  The first time we dissected, the entire class was silently freaking out, worrying who was going to be the one to faint or vomit or burst into tears.  Interestingly, as far as I am aware, that didn’t happen to anyone, and I have only ever seen one person faint in the dissecting room and I think that was just from standing up for too long rather than from touching a dead body.
Whilst dissecting, most of the time my thoughts are along the lines of “Where the fuck is the bloody nerve…oh there is it…oh wait no.  Aaah don’t cut my fingers off. Oh there it is…is it??  Nah….  I’m hungry, yay only 10 minutes till home time!” but every now and again it’s more like “Muscles muscles muscles omg this person was actually a person with thoughts and feelings and a family.  This person got up every morning and put socks on the feet which I am ripping apart with my scalpel.  They probably ate pizza and sandwiches and knew how to swim.  This was someone’s best friend.  They would’ve started school and been terrified.  They had a job, they had a car, then had a house.  They watched TV and read books.  In short, they are just like me.”.
And I’m relieved I have those thoughts.  Intrusive and distracting as they are, I hope I never forget that these people are not just corpses filled with formaldehyde.  They had stories and lives and dreams.  And they were wondering, generous, thoughtful people who had the courage and selflessness to decide to donate their bodies to my medical school for teaching purposes.
Every time we go into the dissecting room, we come scarily close to death.  With the exception of seeing some horrendous car crash, or having a relative pass away or attending a funeral, most people live their lives avoiding death.  This is not the same for medical students or doctors.  Every day we come are faced with our own mortality, we see the fact that life is so precarious and so finite that when we are gone, we are gone.  I’m going to assume that as I get older, I will become less emotionally involved with these things – people have told me that you never forget your first patient, but after that, it’s only the odd few who really make an impact on you.  Deep down, I hope I never lose the shocking innocence I have.  The fact that every time I interview a patient, I feel sad for them and don’t stop thinking about them for days.  The fact that I will never, ever forget the face of the cadaver I spent the year dissecting.  But then, I suppose it would be hard to practice Medicine like this without ending up in a Psychiatric ward something, and I really hope that doesn’t happen to me!

Monday 20 May 2013

lithopedion or stone baby


In an ectopic pregnancy, if the dead foetus is too large to be re-absorbed by the mother's body it becomes a foreign body to the mother's immune system. To protect itself from possible infection the mother's body will encase the foetus in a calciferous substance as the tissues die and dehydrate.
As the calciferous wall builds up, the foetus is gradually mummified becoming a lithopedion or stone baby.
Probably you have never heard of it, it does exist.
Dissected Foetus
Dissected stone baby
Lithopedion Baby
A stone baby

KOBOKO VS MEDICINAL DRUGS IN ATTENTION DEFICIT HYPERACTIVITY DISORDER.



ADHD today is the most commonly studied child psychiatric disorder
and well there there had been a say from the beginning of time for its cure.
Foolishness is bound in the heart of a child; but the rod of correction shall drive it far from him. (Holy Bible prov22vs15).
Recently, i came by a comic picture of the typical Nigerian cane (koboko) with a tag that its been saving life since...........it was discovered it could bring pain that will make a child sober and think. However this brings us to the daily increase in number of children being diagnosed of this illness and it brings this question to mind, Do we have it in Africa?
"ADHD is found to be as prevalent on the African continent as in
Western countries (Meyer, 1998; Meyer, Eilertsen, Sundet, Tshifularo,
& Sagvolden, 2004). The predominant Western approach to
understanding mental disorders is based on a biomedical perspective that
regards primary syndromes as universal and similar across diverse human
cultures. A basic question is to what degree behaviour and its disturbances
are affected by culture".
The inability to inhibit behavioral responses leads to risk taking
behaviour like drug and alcohol abuse, tobacco smoking, premarital and
promiscuous sex, driving anger and traffic offences, accident proneness,
compulsive buying and tattooing and body piercing (Barkley, 2004;
Barkley, Fischer, Smallish, & Fletcher, 2004; Carroll, Riffenburgh,
Roberts, & Myhre, 2002; Fillmore & Rush, 2002; Kahn, Kaplowitz,
Goodman, & Emans, 2002; Lam, 2002; Molina, Bukstein, & Lynch, 2002;
Roberts & Tanner, Jr., 2000; Tercyak, Lerman, & Audrain, 2002).
A high incidence of crime, substance abuse, and especially the very
high rate of HIV infection in South Africa, and its possible relationship to
ADHD, necessitated an investigation into the prevalence and neuropsychological manifestations of the disorder.
So how true is this, will the African child have to be subjected to those drugs Americans think has its management abilities or do we go back to our use of native admonishments like local koboko, pankere and its like?
Pls do comment as ur feedbacks are of utmost importance.

Wednesday 8 May 2013

Mitosis



It consists of two main stages.
Karyokinesis : This is the main part of cell division, which is the division of the nucleus. It is further divided into four stages.
  • Prophase : The nucleus of the cell breaks apart. The individual chromsomes are visible as the chromatids condense.
  • Metaphase : The centromeres of the chromosomes align along what is called as the metaphase plate.
  • Anaphase : The chromatids separate and get pulled apart by the mitotic spindles forming two arrangements.
  • Telophase : The chromatids condense and form the two daughter nuclei of the cell.
Cytokinesis : This stage happens simultaneously with Telophase. It is the final stage where a cleavage is created in the cytoplasm and the cell separates into two daughter cells. The two daughter nuclei pass into the daughter cells.

Individual Brain cells....


UCLA study shows that individual brain cells track where we are and how we move

Using virtual reality, neurophysicists determine how environmental stimuli and brain rhythms generate our neuronal maps of the world

Place cells
Place cells in the real world (l) and in virtual reality. (Click for details.)
Leaving the house in the morning may seem simple, but with every move we make, our brains are working feverishly to create maps of the outside world that allow us to navigate and to remember where we are.
 
Take one step out the front door, and an individual brain cell fires. Pass by your rose bush on the way to the car, another specific neuron fires. And so it goes. Ultimately, the brain constructs its own pinpoint geographical chart that is far more precise than anything you'd find on Google Maps.
 
But just how neurons make these maps of space has fascinated scientists for decades. It is known that several types of stimuli influence the creation of neuronal maps, including visual cues in the physical environment — that rose bush, for instance — the body's innate knowledge of how fast it is moving, and other inputs, like smell. Yet the mechanisms by which groups of neurons combine these various stimuli to make precise maps are unknown.
 
To solve this puzzle, UCLA neurophysicists built a virtual-reality environment that allowed them to manipulate these cues while measuring the activity of map-making neurons in rats. Surprisingly, they found that when certain cues were removed, the neurons that typically fire each time a rat passes a fixed point or landmark in the real world instead began to compute the rat's relative position, firing, for example, each time the rodent walked five paces forward, then five paces back, regardless of landmarks. And many other mapping cells shut down altogether, suggesting that different sensory cues strongly influence these neurons.
 
Finally, the researchers found that in this virtual world, the rhythmic firing of neurons that normally speeds up or slows down depending on the rate at which an animal moves, was profoundly altered. The rats' brains maintained a single, steady rhythmic pattern.
 
The findings, reported in the May 2 online edition of the journal Science, provide further clues to how the brain learns and makes memories.
 
The mystery of how cells determine place
 
"Place cells" are individual neurons located in the brain's hippocampus that create maps by registering specific places in the outside environment. These cells are crucial for learning and memory. They are also known to play a role in such conditions as post-traumatic stress disorder and Alzheimer's disease when damaged.
 
For some 40 years, the thinking had been that the maps made by place cells were based primarily on visual landmarks in the environment, known as distal cues — a tall tree, a building — as well on motion, or gait, cues. But, as UCLA neurophysicist and senior study author Mayank Mehta points out, other cues are present in the real world: the smell of the local pizzeria, the sound of a nearby subway tunnel, the tactile feel of one's feet on a surface. These other cues, which Mehta likes to refer to as "stuff," were believed to have only a small influence on place cells.
 
Could it be that these different sensory modalities led place cells to create individual maps, wondered Mehta, a professor with joint appointments in the departments of neurology, physics and astronomy. And if so, do these individual maps cooperate with each other, or do they compete? No one really knew for sure.
 
Virtual reality reveals new clues
 
To investigate, Mehta and his colleagues needed to separate the distal and gait cues from all the other "stuff." They did this by crafting a virtual-reality maze for rats in which odors, sounds and all stimuli, except distal and gait cues, were removed. As video of a physical environment was projected around them, the rats, held by a harness, were placed on a ball that rotated as they moved. When they ran, the video would move along with them, giving the animals the illusion that they were navigating their way through an actual physical environment.
 
As a comparison, the researchers had the rats — six altogether — run a real-world maze that was visually identical to the virtual-reality version but that included the additional "stuff" cues. Using micro-electrodes 10 times thinner than a human hair, the team measured the activity of some 3,000 space-mapping neurons in the rats' brains as they completed both mazes.
 
What they found intrigued them. The elimination of the "stuff" cues in the virtual-reality maze had a huge effect: Fully half of the neurons being recorded became inactive, despite the fact that the distal and gate cues were similar in the virtual and real worlds. The results, Mehta said, show that these other sensory cues, once thought to play only a minor role in activating the brain, actually have a major influence on place cells.
 
And while in the real world, place cells responded to fixed, absolute positions, spiking at those same positions each time rats passed them, regardless of the direction they were moving — a finding consistent with previous experiments — this was not the case in the virtual-reality maze.
 
"In the virtual world," Mehta said, "we found that the neurons almost never did that. Instead, the neurons spiked at the same relative distance in the two directions as the rat moved back and forth. In other words, going back to the front door-to-car analogy, in a virtual world, the cell that fires five steps away from the door when leaving your home would not fire five steps away from the door upon your return. Instead, it would fire five steps away from the car when leaving the car. Thus, these cells are keeping track of the relative distance traveled rather than absolute position. This gives us evidence for the individual place cell's ability to represent relative distances."
 
Mehta thinks this is because neuronal maps are generated by three different categories of stimuli — distal cues, gait and "stuff" — and that all are competing for control of neural activity. This competition is what ultimately generates the "full" map of space.
 
"All the external stuff is fixed at the same absolute position and hence generates a representation of absolute space," he said. "But when all the stuff is removed, the profound contribution of gait is revealed, which enables neurons to compute relative distances traveled."
 
The researchers also made a new discovery about the brain's theta rhythm. It is known that place cells use the rhythmic firing of neurons to keep track of "brain time," the brain's internal clock. Normally, Mehta said, the theta rhythm becomes faster as subjects run faster, and slower as running speed decreases. This speed-dependent change in brain rhythm was thought to be crucial for generating the 'brain time' for place cells. But the team found that in the virtual world, the theta rhythm was uninfluenced by running speed.
 
"That was a surprising and fascinating discovery, because the 'brain time' of place cells was as precise in the virtual world as in the real world, even though the speed-dependence of the theta rhythm was abolished," Mehta said. "This gives us a new insight about how the brain keeps track of space-time."
 
The researchers found that the firing of place cells was very precise, down to one-hundredth of a second, "so fast that we humans cannot perceive it but neurons can," Mehta said. "We have found that this very precise spiking of neurons with respect to 'brain-time' is crucial for learning and making new memories."
 
Mehta said the results, taken together, provide insight into how distinct sensory cues both cooperate and compete to influence the intricate network of neuronal activity. Understanding how these cells function is key to understanding how the brain makes and retains memories, which are vulnerable to such disorders as Alzheimer's and PTSD.
 
"Ultimately, understanding how these intricate neuronal networks function is a key to developing therapies to prevent such disorders," he said.
 
In May, Mehta joined 100 other scientists in Washington, D.C., to help shape President Obama's BRAIN Initiative (Brain Research through Advancing Innovative Neurotechnologies), with the goal of trying to tease out how this most complicated of organs works.
 
Other authors of the study included Pascal Ravassard, Ashley Kees and Bernard Willers, all lead authors, and David Ho, Daniel A. Aharoni, Jesse Cushman and Zahra M. Aghajan of UCLA. Funding was provided by the W.M. Keck foundation, a National Science Foundation career award grant and a National Institutes of Health grant (5R01MH092925-02).
 
The UCLA Department of Neurology, with over 100 faculty members, encompasses more than 20 disease-related research programs, along with large clinical and teaching programs. These programs cover brain mapping and neuroimaging, movement disorders, Alzheimer's disease, multiple sclerosis, neurogenetics, nerve and muscle disorders, epilepsy, neuro-oncology, neurotology, neuropsychology, headaches and migraines, neurorehabilitation, and neurovascular disorders. The department ranks in the top two among its peers nationwide in National Institutes of Health funding.