At the beginning of this year I had this idea to read as many medical student blogs as I can. So the first thing I did was to search for those medical student bloggers. As I said in an earlier post, I found more than a hundred blogs. To keep track of them I subscribed to all of them. I used to read some blogs more than others. There was a huge difference in quality and writing talent among bloggers. Some with no doubt could write for magazines. Some are just having fun. And some blogs were no more than an electronic public diary.
Yesterday I made up my mind and decided to let go and un-subscribe to the blogs that there was no more use for me to follow.
From about 150 feeds in my reader, now I only have 60.
I will not list the ones I read or the ones that I wont be reading regularly anymore but I do want to point to some outstanding blogs that I think medical students can benefit a lot from.
So, here are some feeds that I recommend for medical students(in no particular order):
Too bad Lonely Coyote from Medical Student Musings and Graham from Over My Med Body both stopped blogging once they became residents. Their blog's were really interesting and helpful.
Please do not get me wrong. Most of the blogs were great. But some were too advanced for me and some were just ... lets say not my style.
My blog still didn't reach its first birthday. I still did not find a certain niche for it. If you have any advice or suggestions, please do not hesitate in contacting me.
Point mutation: The substitution of a single nucleotide in the geneticmaterial of an organism. These include silent, missense, and nonsense mutations.
Silent mutation: A single nucleotide is exchanged by another, but this alteration does not change the amino acid for which the codon codes. The final protein product remains unchanged.
Missense mutation: A single nucleotide is exchanged by another, and this alteration does have an effect on the coding amino acid. The final protein product is also modified. The modification may or may not be deleterious to the final protein, depending on the function of the amino acid.
Nonsense mutation: A single nucleotide is exchanged by another, which produces a new stop codon at this position. This premature stop codon generally results in a truncated form of the protein and most often leaves it as an inactive form.
Deletion: One or more nucleotides are removed from the genetic sequence. If the deletions are multiples of one or two, a frameshift will be the result, which will likely damage the final protein product. A deletion of three or a multiple of three does not shift the reading frame, rather it would merely remove a codon(s). The final protein product would lose amino acid(s), which may or may not leave it inoperative.
Insertion: One or more nucleotides are added to the genetic sequence. These are the opposite of deletions.
Trinucleotide repeat expansion: Amplification from one generation to the next of three nucleotide repeats in the coding or noncoding regions of DNA. The mechanism may arise from DNA complimentary strand slippage. This is associated with fragile X syndrome and myotonic dystrophy.
DNA methylation: Process by which methyl groups are added to DNA bases (most often cytosine). Methylation functions to regulate gene expression because heavily methylated genes are not expressed. Also, bacteria use methylated DNA as a defense mechanism. Every organism has different patterns of methylated DNA, and bacteria take advantage of this by destroying foreign DNA via nucleases, enzymes that cut DNA at specific sites.
--------------------- Source: Biochemistry Case Files, clinical cases, case 13 ,page 123 .
Fragile X syndrome is the most common known cause of intellectual disability, also known as mental retardation, and developmental disability that can be inherited (passed from one generation to the next).
Physical and behavioral signs that a child has fragile X syndrome include:
• Not sitting, walking, or talking as early as other children (this is known as having developmental delays)
• Learning disabilities
• Speech and language delays
• Behavioral problems such as attention-deficit/hyperactivity disorder (ADHD)
Children often have a typical facial appearance that gets more noticeable with age. These features include:
• A large head
• A long face
• Prominent ears, chin, and forehead
Males who have fragile X syndrome usually have some degree of intellectual disability that can range from mild to severe. Females with fragile X syndrome can have normal intelligence or some degree of intellectual disability with or without learning disabilities. Autism spectrum disorders also occur more frequently in children with fragile X syndrome.
A little more in depth:
The fragile X syndrome is a genetic disorder caused by mutation of the FMR1 gene on the X chromosome. Mutation at that site is found in 1 out of about every 2000 males and 1 out of about every 259 females. (Incidence of the disease itself is about 1 in every 4000 females.)
Normally, the FMR1 gene contains between 6 and 55 repeats of the CGG codon (trinucleotide repeats). In people with the fragile X syndrome, the FMR1 allele has over 230 repeats of this codon. Expansion of the CGG repeating codon to such a degree results in a methylation of that portion of the DNA, effectively silencing the expression of the FMR1 protein. This methylation of the FMR1 locus in chromosome band Xq27.3 is believed to result in constriction of the X chromosome which appears 'fragile' under the microscope at that point, a phenomenon that gave the syndrome its name.
Mutation of the FMR1 gene leads to the transcriptional silencing of the fragile X-mental retardation protein, FMRP. In normal individuals, FMRP binds and (usually) inhibits the translation of a number of essential neuronal RNAs. In fragile X patients, however, these RNAs are translated into excessive amounts of protein. However, certain RNAs seem to be stabilized by FMRP through a different mechanism.
A researcher holds one of the completed lenses developed by engineers at the University of Washington (UW). The lenses were tested on rabbits for up to 20 minutes and the animals showed no adverse effects. A virtual display like this could be used by drivers or pilots to see a vehicle's speed projected onto the windshield; by video-game companies who could use the contact lenses to completely immerse players in a virtual world without restricting their range of motion; or, in the field of communications, by people on the go who could surf the Internet on a midair virtual display screen that only they would be able to see.-Read More
-------------------------------------- Source and photo credit: NSF dot gov
At last Blogger released its own subscription tool for its blogs (check the first two options in my blog's side bar). Now we do not need to go through the headache of generating our own subscription links from other sites and having to figure out our blogs' RSS or Atom links. I think all bloggers on Blogger should add this new feature. And while you are at it do not forget to subscribe to my blog ;)
BRFSS data highlighted in the report shows a large difference between the percentage of smokers advised to quit and those additionally offered help.
In 2005, 47.9 percent of smokers reported that healthcare professionals advised them to quit smoking in the past twelve months. In contrast, only 27.5 percent reported that healthcare professionals offered them help to quit during the same timeframe. This help can include medication assistance or other strategies. Read more
To be effective, advice to quit smoking must also include such offers of assistance. The Partnership for Prevention estimates that 42,000 additional lives would be saved each year if the United States increased to 90 percent the portion of smokers who are advised by a health professional to quit and are offered medication or other assistance.
What are the long-term benefits of quitting smoking? Quitting smoking reduces the risk of cancer and other diseases, such as heart disease and lung disease, caused by smoking. People who quit smoking, regardless of their age, are less likely than those who continue to smoke to die from smoking-related illness. Studies have shown that quitting at about age 30 reduces the chance of dying from smoking-related diseases by more than 90 percent. People who quit at about age 50 reduce their risk of dying prematurely by 50 percent compared with those who continue to smoke. Even people who quit at about age 60 or older live longer than those who continue to smoke.
Print resources: For cutting-edge, evidence-based tools designed to help specific audiences quit smoking and remain smoke-free, look no further. They can be viewed online, downloaded in PDF format, or ordered online by selecting the appropriate link below. Click here
Cigarette smoking remains the leading preventable cause of death and disease in the United States, causing the death of nearly 500,000 deaths each year. This report discusses the importance of aids that will help smokers quit, thus decreasing illness and death caused by smoking. Podcast
Diagnosis: a throat swab is taken to the laboratory for testing. A Gram stain is performed to show Gram positive, cocci, in chains. Then, culture the organism on blood agar with added bacitracin antibiotic disk to show beta-haemolytic colonies. Then, perform catalase test, which should show a negative reaction for all Streptococci. Antigenic detection ELISA. PCR.
Treatment of choice: penicillin
Enterococci
Gram positive diplococci
Non hemolytic
Short chains or pairs
Commensal in GIT
E. faecalis and E. faecium are the most commonly associated with disease
Diagnosis: Specimen - Direct film Gram Stain - Culture non hemolytic - Mac Conkey agar small pink colonies, they have the ability to survive in the presence of bile - Catalase -ve - Ferment mannite - rapid reduction litmus milk, changes from violet to white color (decolorization)
Some new enterococci emerged in the US that is resistant to vancomycin
Streptococcus Viridans
Gram +ve
Viridans = Green
Either Alpha hemolytic and produce a green color in culture or non hemolytic
Commensal of Upper respiratory tract and buccal cavity
Diagnosis: Specimen ... - Gram stain ... - Culture ... -Viridans streptococci can be differentiated from Streptococcus pneumoniae using an optochin test, as Viridans streptococci are optochin resistant.
Diagnosis: Depending upon the type of infection present, an appropriate specimen is obtained accordingly and sent to the laboratory. A Gram stain is first performed to guide the way, which should show typical gram-positive bacteria, cocci, in clusters. Secondly, culture the organism in Mannitol Salt Agar, which is a selective medium with 7–9% NaCl that allows S. aureus to grow producing yellow-colored colonies as a result of salt utilization and subsequent drop in the medium's pH. Furthermore, for differentiation on the species level, catalase (positive for all species), coagulase (fibrin clot formation), DNAse (zone of clearance on nutrient agar), lipase (a yellow color and rancid odor smell), and phosphatase (a pink color) tests are all done. For staphylococcal food poisoning, phage typing can be performed to determine if the staphylococci recovered from the food to determine the source of infection.
Treatment: Depending on the case DOC may be, Penicillin G, methocillin, oxacillin, or vancomycin.
Disease: diphtheria: sore throat, pseudomembrane in pharynx, myocarditis, neural involvemnnt
Diagnosis: gramstain-culture
Neisseria Gonorrhoeae
Kidney Bean Shaped
Gram Negative Diplococci
Ferments only glucose not maltose (remember there is only a "G" in gonorrhoeae and no "M")
Pili
IgA1 protease
Protein I
Protein II
Endotoxin no exotoxin
Diseases: Men,urithritis-Women, cervial gonorrhoeae-Both men and women, gonococcal bacterimia, septic arthritis-Neonates, neonatorum, conjunctivitis
Diagnosis: Gram stain of urethral pus-Culture
No immunity after infection, a person can be reinfected many times
Neisseria Meningitidis
Gram Negative
Kidney Bean shaped diplococci
5-10% of of normal healthy individuals are are carriers for meningococci in the nasopharynx
Oxidase +ve
Polysaccharide capsule
90% of cases are caused by serogroups A, B, and C
Capsular polysaccharide Ag
Lipopolysaccharide
IgA prtease enzyme
Transferrin
Ferments maltose and glucose (remember there are both a G and an M in meningitidis)
Endotoxin, no Exotoxin
Diseases: Meningitis - Septicemia
Diagnosis of case: Specimen - Check CSF turbidity, neutrophils, protein, glucose, - centrifuge - Supernatant capsular Ag - Deposit - Culture on chocolate blood or Thayer Martin - Oxidase +ve
Diagnosis of carrier: Specimen - Culture chocolate blood or Thayer Martin Medium
Treatment: 3rd generation cephalosporins
Prophylaxis: Vaccine, capsular polysaccharide antigen A, C, Y, W135 - Rifampin for children - Ciprofloxacin for adults
Bonus notes:
The most common cause of infective endocarditis is skin infection with staphylococci as a result of intravenous drug abuse followed by Streptococcus viridan.
Amoxicillin is givin before any dental procedures in patients with rheumatic fever or with prosthetic heart valves.
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All images are in the public domain or licensed under a creative commons. Thanks to cdc.gov and wikipedia.org
In the field of neuroscience, a connectome is a detailed map of the full set of neurons and synapses in an organism. The study of this map is known as connectomics.
John G White co-developed confocal microscopy and mapped the complete nervous system of C. elegans, consisting of 302 neurons and over 7000 synapses. The study was published in 1986 by the Philosophical Transactions of the Royal Society of London, and is considered to be the first work in the emerging field of connectomics. White received his Ph.D. from University of Cambridge in 1974 and is currently a Professor of Anatomy and Molecular Biology at the University of Wisconsin-Madison.
Mapping The Most Complex Structure In The Universe: Your brain (WIRED dot com)
Harvard scientists have embarked upon an ambitious program to create a circuit diagram of the human brain, with the help of new machines that automatically turn brain tissue into high-resolution neural maps. By mapping every synapse in the brain, researchers hope to create a "connectome" -- a diagram that would elucidate the brain's activity at a level of detail far outstripping today's most advanced brain-monitoring tools like fMRI. READ MORE
TR10: Connectomics (Technology Review dot com)
Lichtman's technology--developed in collaboration with Jean Livet, a former postdoc in his lab, and Joshua Sanes, director of the Center for Brain Science at Harvard--paints nerve cells in nearly 100 colors, allowing scientists to see at a glance where each axon leads. Understanding this wiring should shed light on how information is processed and transferred between different brain areas. READ MORE
Hi guys. How are you doing? Sorry I have been away for sometime. The last few days, I have been spending time on the infamous Facebook. I just signed up over there 3 days ago after a resistance that lasted almost a year. I will share my opinion later on. For now, relax and enjoy this funny song about facebook:
Note: if you do not use this network you will not get it.
If you would like to add me as your friend on Facebook, let me know in the comments section and I will contact you.
