test day

its test day. so, im not really learning anything new, just memorizing and reviewing. so, please take the time to go to this website and "sign a cast." it takes less than 30 seconds and someone will donate $5 to a kid who needs a surgery.
http://www.helpcurenow.org/site/c.nvI1IeNYJyE/b.4137607/k.9A91/Sign_a_Cast.htm

thanks!

alcohol poll and dysdiadochokinesis

i'm a little surprised at the poll results. some have quite a bit of alcohol experience(zero order kinetics), some have none (i have no idea or first order kinetics), and others are just plain alcoholics (mmm... alcohol). it turns out, as emily so expertly pointed out that alcohol is a mixed order or dose dependent. when a drugs elimiation is mediated predominantly by metabolism, its elimination will tend to follow first order kinetics when concentrations are well below the Km of the metabolic enzymes, but will follow zero order kinetics at high doses that greatly exceed the Km of the metabolic enzymes due to saturation of the metabolic pathways. alcohol is one such drug.

so congrats to those of you who voted, you're all a little wrong, and all sort of correct. just remember... "you don't booze, you don't win. you booze you win. you don't booze you don't race you don't win, you booze you race you win."

dysdiadochokinesis: the ability to preform rapidly alternating movements. this is impared in cerebellar damage. so whatever you do this fine weekend, don't damage your cerebellum!

smooth pursuit... not just a nickname for a girl i know...

first let me say that its almost midnight and im still at school studying, and i have to say that medical school is perhaps the coolest thing that i have ever done and i feel so privlaged to be here. let me tell you what i have learned today.

smooth pursuit: this refers to the eyes tracking an object slowly across your visual field. the ability comes for the occipital lobe. however, it is impossibe to do this unless you are following an object. try it. start at the corner of the ceiling and try to slowly move your eyes to the other corner. your eyes will jump from spot to spot. now follow your finger, its a smooth movement. clinical application: this is how you tell if a schizophrenic person is really seeing something, if they can smoothly track it with their eyes. crazy, huh?
btw, the fast movement of your eyes is controlled by the frontal lobe of the brain.

random fact: men have a 1:2 chance of getting some form of cancer anywhere in the body during their lifetime. guys, look at your roomate/cubicalmate/playmate (oh, wait...) and chances are either you or they will develop cancer. most likely cancer? prostate, 1:6 chance.

tonight i was walking across the atrium of the school and tripped, but didn't fall. at first i blushed and hoped that no one saw. then i just realized that i knew the pathway that fired to keep me upright. my semicircular canals sent a signal to the vestibulochocler nerve (Crainial Nerve VIII) to my cerebellum through the inferior cerebellar peducle to the flocculonodular lobe, then to the fastigial nucleus, then out to the vestibular nuclei then down the spinal cord thru the lateral and medial vestibulospinal tract to my arms and legs to respond to keep me from falling. and it all took place in less than a second without me even thinking about what i was doing. amazing!

thank God we have such amazing and complex systems. i really am in awe of the body im struggling to learn about.

what to look forward to tomorrow? dysdiadochokinesia. (it really is a word, i promise)

hijacking viruses

many diseases are characterized by the lack of something, perhaps an enzyme. or sometimes it is benificial to provide a growth factor. in these cases, it would be benificial to add a gene to a cells DNA. but how? well, some really smart people realized thats what viruses do, so why not hijack them and make them work for us? so they did. there are 5 kinds of viruses we use.
1)adenovirus- most commonly used; infects respiratory epithelium,
disadvantages- very immunogenic (causes immune reaction), infection only lasts a few months
2)adeno-associated virus - infects many cell types, no immune response
disadvantage- hard to harvest to any large number
3)retrovirus - used to treat immune deficiencies, generated in high titer
disadvantage- only integrates into dividing cells, and the site of intigration is unpredictable so it could insert anywhere and cause cancer!
4) lentivirus - virus associated with HIV, infects all cells, gene expression lasts for years
disadvantage - site of integration unpredictable
5) herpesvirus - (yes, as in herpes the STD), infects neurons
disadv. - large and dificult to use

once you insert a gene via a virus, it is always there, you can never get it out. so, hope you don't screw up! what they started doing is inserting a progene, meaning you have to give a drug or something to make that gene active. when you don't want the gene to be expressed anymore, then you stop taking the drug. kind of eliminates the purpose of inserting the gene in the first place (so you don't have to remember to take your drug) but it still has its advantages.

amazing drug that keeps on giving!

i still can't get over how cool this one is... so some really smart people realized that our cells secrete a molecule we decided to call "nerve growth factor" (NGF). they then thought, well, if it does what it's called, then why don't we use it to treat neuronal degenerative diseases? so they did. how did they deliver it? the took a really long needle and injected it into the lateral ventricles! that is in the very center of your brain! they had to go through the skull, through the brain and sinuses and meningies and all that menusha with a needle! unbelieveable. turns out the patients all developed debilitating neuropathies, so they stopped the trial. but not done yet. they are currently back at it, but delievering it a diferent way.
round 2: they are implanting genetically engineered fibroblasts (special type of cell) that secrete NGF into the forebrain! awesome right? thats like putting a drug into the sight of action that just keeps on giving! so far, they are having great success at improving cognitive function in diseases such as alzheimer's.

there are some pretty awesome other techinques they are using or developing, but i have to go learn about them right now. more later...

alcohol

in pharm drugs fall in to two classes of kinetics. first order or zero order. it deals with their clearance, or how fast the drug is eliminated from the body. first order kinetics is what almost all drugs are. first order drugs are cleared with a constant half-life. this means that they are concentration dependent. the more drug present, the faster it will be cleared. zero-order kinetics means that the drug clearance is constant. it does not have a constant half life. so if you have a huge amount of that drug in your system, it will be eliminated from the body at the same rate is if you had just a little. the drug metabolism pathways are saturated.

I'm going to make this post interactive. take my poll. from your experience with drinking, do you think alcohol is first order or zero order?

stroke

when someone has a stroke in the right brain, they have left sided symptoms. this is because the motor neurons cross to the other side in the lower medulla. the top of the face, such as your forehead does not experience these symptoms however, because the motor neurons that control these muscles come from both sides. cool huh?

branchial arch's

the first pharyngial arch gives rise to the muscles of mastication and they are innervated by cranial nerve V
the second pharyngial arch gives rise to the muscles of facial expression innervated by CN VII
the thrid is the pharynx/larynx innervated by CN's IX and X.

also the lateral cuneate nucleus sends out tracts known as the cuneocerebellar tract that enters the cerebellum via the inverior cerebellar peduncle, along with the DSCT (dorsal spinocerebellar tract), fibers from the contralateral inferior olive, and im pretty sure there is one more but i can't remember the name...

out like gout...

actually tophaceous gout. i saw it today in clinic. it was crazy. huge bony-looking growths on the olecranon process (elbow) and digits (fingers). it is cause by a deposit of monosodium urate crystals from an over production or under excretion of uric acid. it accumulates in the soft tissue, usually joints, especially the first metatarsophalyangeal joint (big toe). when this happens its called podegra. tophaceous gout occurse when tophi (bumps) appear on the joints, usually 12 years after they have had hyperuricemia.

acute treatment - NSAIDs or colchicine. colchicine you give at increasing doses until they have diarrhea, then you back the dose down a bit and keep them at that level. i prescribed colchicine tonight.

chronic treatment - keep the patient on NSAIDs or colchicine and treat the hyperuricemia, but not until the acute episode is over, or you can mobilize the crystals. typical drug is allopuronol.

my attending tonight told me to go home and look up this disease and the treatment because i saw it in clinic and would never forget it. i hope he is right. thanks RL, your huge tophi are engrained into my memory forever.

sad med school fact

i think i studied for 8 hours today and i cant tell you what i learned. my brain is toast.

Lou Gehrig's Disease

fact #6

ALS or amyotrophic lateral sclerosis, aka Lou Gehrig's Disease. This one is crazy. You start to notice weakness or stiffness or cramping in your arms and/or legs. You go to the doctor, they diagnose you with ALS if your lucky*. Lucky not because they can do anything, you just know that you will die a terrible death in 3-5 years. The nerves in your ventral grey horn in the spinal column die, causing you to loose all function of your voluntary muscles (save your eye muscles, oh boy!) You cant swallow, protect your airway, or talk. but your muscles do spontaneously twitch, until they completely atrophy. Then you die because you cant contract your diaphragm (from the phrenic nerve, cervical roots 3-5).

Whelp, sorry this is a pretty morbid post. I went for the longest run of my life today (16 miles) for two reasons. one because im training for a marathon. the second reason is because i can. the longer im in medical school and the more i learn about these terrible diseases, the more i just want to drop out of medical school and enjoy life. it can go so fast. if your diagnosed with pancreatic cancer, you usually have about 3 months to live and then your 6 feet under.

so, i end with this, a challenge to get outside and do anything. and thank God that you can.

fact #5

graphesthesia is a neurological test used to examen higher brain function. the doctor draws on the hand of the patient, and they should be able to recognise the nuber or letter that was drawn. if they cant, it could be the sign of a previous stroke has occured.

repetitio est mater studiorum

repetition is the mother of learning...

so i failed already in posting everyday, but i'll make up for it. let me explain where i have been. while leaving clinic tuesday night, i realized my friends window had been smashed and our backpacks were stolen, along with our notes and books. bummer deal. it actually really upset me more than i thought. I guess God is teaching me to hold my possessions more loosely. They are his after all...

cool fact #2:
there is a drug, the name escapes me (i left my binder at school) that is extracted from the saliva of a leech!

fact #3
we started behavior development today. we looked at a CT of a healthy 3 yo baby brain compared to a neglected (only socially, but still well fed) 3 yo brain. the neglected one was literally half the size! i couldn't believe it, infact i just stared at the screen with my mouth open for a while, thinking of my sister who was raised in an orphanage until age 4. i guess that explains a lot.

fact #4
i thought i diagnosed my mom today with hyperekplexia aka "startle disease" mom jumps every time her phone rings. sounds like a diagnosis, right? well, turns out its a bit more severe than that. these spasms can actually mimic seizures, leading to apnea and death. well, i was wrong with my first diagnosis (thank goodness) but i'm still searching...

hello world... im an M2

so, i really hate to write. in fact, that's probably why i was a science major in undergrad. that was my assurance that i wouldn't have to write many papers. i'll take a test any day over having to write a paper.

so why start a blog? well, i have a couple friends who blog. they convniced me to try it. and, in a futile attempt to remember the vast amount of knowledge that is expected to be memorized by medical students, i have devised a plan to help remember this stuff. I'll try to post once a day the most interesting, or obscure, or perhaps just the fact that i find hardest to memorize. maybe this way I'll be able to convert that bit of information into a neuronal synaptic pattern in my brain that will fire when prompted on a test. without any further blogging, today's fact:

100,000 people a year die from pharmacological errors. that seems like a high number to me. it might be a good idea to question your doctor, nurse, or who ever is giving you that injection/pill/iv drip next time...