Encapsulated Organisms

The mnemonic in the Kaplan Lecture Notes is better than the one in First Aid. Here it is: Some Killers Have Pretty Nice Capsules

1. Streptococcus pneumoniae
2. Klebsiella
3. Haemophilus influenzae
4. Pseudomonas aeruginosa
5. Neisseria meningitidis
6. Cryptococcus neoformans

 There are some others (not as important) including:

1. some E. coli
2. Streptococcus agalactiae
3. Yersinia pestis (F1 envelope)

Clubbing

The causes of clubbing (hypertrophic osteoarthropathy) are CLUBBING:

1. Cyanotic heart disease
2. Lung diseases (hypoxia, cancer, bronchiectasis, cystic fibrosis)
3. Ulcerative colitis
4. Biliary cirrhosis
5. Birth defect
6. Infective endocarditis
7. Neoplasms (e.g. Hodgkin's)
8. GI malabsorption

Myocardial Infarction

Myocardial Infarction is definitely a topic you're bound to run into on the USMLE step 1 exam. Here are 2 mnemonics that may help you out.

Sequence of Elevated Enzymes in Myocardial Infarction:  Time to CALL 911

 Troponin, CK-MB, AST, and LDH1-2

Complications of an MI:  ACT RAPID

1. Arrhythmia
2. CHF
3. Thromboembolism (from a ventricular aneurysm)
4. Rupture (of ventricular wall, papillary muscle, or IV septum)
5. Aneurysm (of ventricle) 
6. Pericarditis
7. Infarction (a second one)
8. Dressler syndrome

The Ultimate Study Guide for Gastrointestinal Hormones

A lot of people struggle with GI hormones during their Physiology course or during USMLE Step 1 Preparation. Hopefully this will help.

All together there are 8 major hormones in this table. We are going to group these into 3 groups:

1. Hormones that affect the stomach: the first 4 (Gastrin, CKK, Secretin, GIP)
2. The inhibitory hormone: Somatostatin
3. Hormones that affect intestinal motility: the bottom 3 (NO, VIP, and Motilin)

For the most part, the hormone's name will give away its function.
1. Gastrin: this is the only hormone that promotes GASTRIC functions (acid secretion and motility)
2. CKK: “cholecyst” means gallbladder, “kinin” means move. Therefore, this is the only hormone that causes gallbladder contraction. Remember that bile is important for lipid digestion (formation of micelles, etc.). What else is important for lipid digestion? Pancreatic lipase! Therefore, CKK also increases secretion of Pancreatic enzymes. The fact you need to memorize here is that CKK decreases gastric emptying.
3. Secretin: promotes pancreatic HCO3- secretions. Since this hormone promotes an alkaline pH in the duodenum, it also inhibits gastric acid secretion.
4. GIP: GIP stands for 2 things
     a. Gastric inhibitory polypeptide: referring to its function in reducing gastric acid secretion.
     b. Glucose dependent insulinotropic polypeptide.
5. Somatostatin: inhibits all secretions (acid, pepsinogen, HCO3-, pancreatic enzymes, insulin, glucagon). It does not affect motility.
6. NO: you know that nitric oxide is the ultimate smooth muscle relaxer, so it reduces motility and relaxes sphincters.
7. VIP: “active” indicates that it increases intestinal motility.
8. Motilin: you can tell from its name that this hormone also promotes intestinal motility.

Go over the actions one more time just to make sure you’ve got them. Then move on to Regulation:
1. Stomach distension increases motility of the stomach (via Gastrin) and intestine (via VIP). When the stomach’s full, you want the food to move along to the next part of the GIT.
2. Acidity: when the stomach is too acidic, you’ll want to bring the pH back to normal by decreasing acid secretion. This is done by decreasing Gastrin (which normally increases acid secretion), and increasing secretin and Somatostatin (which decrease acid secretion).
3. Glucose: when there’s glucose in your GIT, you’ll want to get ready for it by having insulin available. This is done via GIP. Note that GIP secretion is also stimulated by amino acids and fatty acids.
4. Fatty acids and amino acids each increase the secretion of 3 hormones.
     a. Both amino acids and fatty acids increase the secretion of CCK and GIP.
     b. Amino acids also increase secretion of Gastrin [think: proteins are digested by pepsin, which is derived from activation of pepsinogen by acid ].
     c. Fatty acids also increase secretion of Secretin [think fatty acids are digested by pancreatic lipases  which require an alkaline pH to function]
5. Vagal stimulation increases Gastrin and VIP. It also decreases Somatostatin.

Done with Physiology

I just finished Physiology today. It took me a bit longer than I had planned. Overall, physiology is one of my strengths. I found that First Aid for the USMLE Step 1 2010 was only decent for physiology. It did cover most of the high yield topics, however I found it a bit lacking in certain areas, especially Endocrine and Cardiovascular Physiology. For Cardiovascular Physiology, I made a lot of annotations and page references to the Kaplan lecture notes. For Endocrine physiology, what First Aid lacks, Rapid Review Pathology has. I actually ended up reading the whole endocrine chapter from Rapid Review Pathology. I'm probably going to do the practice questions in the Kaplan Qbook by the end of the day. Next in my USMLE Step 1 prep is Microbiology, my least favorite subject. I still haven't created a plan for Micro, but I'm going to work on that before going to bed. Wish me luck!

Hypoxemia Algorithm

This algorithm is important. The information it contains is not found in First Aid for the USMLE Step 1, so you should definitely copy it in there.
*FIO2 stands for fraction of inspired oxygen.

Biochemistry

I've just finished Biochemistry. I went through the Biochemistry section in First Aid and then annotated some extra information from the Kaplan Lecture notes. I honestly think First Aid covers Biochem sufficiently. I did the 2 Qbook practice tests with an average of 86% questions right, so I'm satisfied with myself for this subject.

 

In my opinion, the highest yield topic in First Aid Biochemistry is the Rate-limiting enzymes. I'm definitely going to review this page the day before my exam. Not as high yield but difficult to retain for me were the Lysosomal storage diseases and the Glycogen storage diseases, so I'm also going to review these 2 pages again the day before my exam.

 

My next step in USMLE Step 1 prep is Physiology! I'm going to try to get through it all in 6 days, and I'm going to have to work hard to achieve that!

 

Here is a list of the major Biochemistry annotations I added from the Kaplan lecture ntoes (I have the 2006-2007 edition):

• Comparison between Prokaryotic and Eukaryotic DNA Replication: Kaplan pg. 22
• Genetic regulation: Kaplan pg. 69-77
• Transcription: Kaplan pg. 35-38 + pg. 43
• Indirect Genetic Diagnosis: Kaplan pg. 385-388
• Gene mapping: Kaplan pg. 366-376
• Algorithm for the Modes of Inheritance of a disease: Kaplan pg. 298 (Figure II-I-11)
• Vitamins: I'm not going to study these from First Aid because I felt Rapid Review Pathology covered these better. So I crossed them out in First Aid and made a page reference to Rapid Review Pathology.
• SAM, B12, and Folate: Kaplan pg. 257-259
• Overview of Energy metabolism: Kaplan pg. 153-159
• Functions of NADPH: Kaplan pg. 205
• Transport of ammonium by glutamine: Kaplan pg. 250
• VOMIT Pathway and enzyme deficiencies: diagram in Kaplan pg. 186      VOMIT (Valine, odd chain fatty acids, methionine, isoleucine and leucine, and threonine are all gluconeogenic and enter this pathway)
• Ketogenesis and Ketolysis: Kaplan pg. 237-239
• Triglyceride synthesis: Kaplan pg. 214-215

Cofactors

Carboxylases require ABC: ATP, Biotin, and CO2

Pyruvate dehydrogenase, a-ketoglutarate dehydrogenase, and Branched chain amino acid dehydrogenase require 5 cofactors: "Tender Love & Care For Nancy"
1. TPP (from B1)
2. Lipoic acid
3. CoA (from B5)
4. FAD (from B2)
5. NAD (from B3)

Glycogen bonds

The point at which a glycogen branch forms is an α-1,6 bonds (BRANCH has 6 letters in it)

The rest of the glycogen molecule has α-1,4 bonds (REST has 4 letters)

Hyperbilirubinemia

This table is based on the one in Rapid Review Pathology. I've just added some of the extra information about the different types of jaundice to make it more complete.

Splenomegaly

Protein Synthesis Inhibitors: Never Mix Them Up Again!

Aminoglycosides: A is the 1st letter, thus aminoglycosides inhibit Initiation (the first step of translation) by preventing formation of the initiation complex.

ChloramPhenicol: the only one with a "P", thus the only one inhibiting Peptide bond formation (by peptidyltransferase)

Macrolides: prevent the Movement of ribosomes (translocation)

Clindamycin: makes ribosomes Cling to mRNA (prevents translocation)

Tetracyclines (TTC): tRNA Tries but Can't (prevents the aminoacyl-tRNA from attaching to the A site of the ribosome)

Lincomycin: Like erythromycin (prevents translocation)

Linezolid: Like an aminoglycoside (prevents initiation)

Developmental Milestones

This chart is a hybrid between the ones in Kaplan Lecture Notes, First Aid for the USMLE step 1, First aid for the basic sciences, and a few other resources. The bottom row of the table (the "others" row) has mnemonics for each age. The mnemonics cover a great deal of what's in the table, however there is still a lot of information that is not covered by the mnemonics, so you're still going to have to put in a lot of effort if you want to master this.

Need to get organized

As the number of posts grows, the lack of organization here is becoming more evident. I am going to work on this throughout these next few days. I'm going to create separate pages and hopefully re-organize my posts. This is going to be very GRADUAL since I don't have  alot of time to spare. I look forward to getting it done though and I'm sure it will make coming to my blog more enjoyable for you. :)

Intestinal Obstruction mnemonic

Here is a mnemonic I made up for the Causes of Intestinal Obstruction:

CHAGAS is Very Important in Hispanic Municipalities


Chagas disease can lead to Hirschprung's disease because the tryponosomas can destroy the ganglion cells in the rectum. Hirschsprung's is itself a cause of intestinal obstruction.
C= Crohn's disease
H= Hirschsprung's disease
A= Adhesions
G= Gallstone ileus
A= Atresia (duodenal)
S= pSeudoobstruction (neurogenic)

is Very= Volvulus

Important= Intussusception

in Hispanic= Hernia (Indirect)

Municipalities= Meconium ileus

My Greatest Fear

Imagine waking up one morning only to discover that you're trapped in your body! You open your eyes to frantically discover that you're still alive. You role your eyes down to look towards your legs and they're still there, but unable to move. You're completely paralyzed, can't speak, can't yell for help...all you can do is move your eyes up and down. The only movement you have left in your body consists of vertical movements of the eyes because the only 2 nerves spared in this state are the oculomotor and trochlear nerves. You can hear yourself think, you can hear people around you speak, you can even understand what they're saying, but you're trapped! A prisoner of your own body. You can't express to anyone around you that you're scared to death or want to cry.

This is what is experienced by thousands of unlucky people with "Locked in syndrome" or cerebromedullospinal disconnection. It is caused by a lesion at the base of the pons such as an infarct of the basilar artery.

Corticospinal tracts are lost, meaning you have no movement in your body.
Corticobulbar tracts are lost, meaning that you have no movement in your face and can't speak. All you have are the up and down movements that you can perform using the oculomotor nerve.

This is the scariest disease to me. I would probably prefer to have any other disease than this.

Hypothalamus (hunger vs. satiety)

The hypothalamus has both the hunger center (lateral area) and the satiety center (ventromedial area).
I honestly didn't like the mnemonic in first aid for this. The mnemonic I like is this:
Lat makes you fat (hunger center)
Ven makes you thin (satiety center)

Brain Stem Lesions Simplified

I've been going through Anatomy these past few days A(for the second time now). I'm almost done. Neuroanatomy was the hardest section for me and took the most time. I despise the Brainstem section in Kaplan. I created a table to summarize the Brain stem lesions. It includes information from Kaplan, First Aid, and HY Neuroanatomy. It took time to create but it was worth it in the end.

Extraordinary Measures

I decided to take some time off today to watch the movie Extraordinary Measures. I loved it! It is one of my favorite "medicine-based" movies.

It is about a family with 2 kids who have Pompe's disease and how their parents create a foundation that plays the major role in developing a drug for the disease (the drug is a replacement enzyme that can enter the cell and perform the functions of the deficient enzyme). What is amazing about this movie is that it is based on the true story behind the development of the drug "Myozyme" (alglucosidase alpha) by the company Genzyme which has been available since 2006. Go to http://www.myozyme.com/ to learn more about the drug. I strongly suggest you watch the movie Extaordinary Measures.

Cushing Ulcers and Curling Ulcers

These are peptic ulcers caused by CNS injury and burns respectively.

One possible explanation for the development of Cushing ulcers is the stimulation of vagal nuclei due to the increased intracranial pressure which leads to increased secretion of gastric acid.

Curling ulcers may be explained by a reduced plasma volume, which leads to sloughing of the gastric mucosa or secretion of burn toxins (necrotic and carbonaceous materials released from burned cells) by the stomach.