Atherosclerosis: Foam Cell Macrophages

Rubber Ducky, you're the one. 

Pathogenesis of atherosclerosis: when monocytes differentiate into macrophages in the subendothelial wall of arteries, exogenous cholesterol from abnormal lipoproteins enter the cell via surface molecules called scavenger receptors.  

These scavenger receptors may include the molecules CD36 and SRA. 

Once the cholesterol is in the macrophage and stored as droplets, the cell is considered a foam cell. 

ECG: QT Interval

Another obscure pie reference unrelated to this post = the "pie in the sky" visual field defect

I know that this post is not directly related to pathology, but it's still medically-oriented so here we go!

Here's a poorly drawn electrocardiogram. From a 12 lead ECG, your reading from lead II should look somewhat like this, but not as bad. 

In layman's terms: each peak and valley represents different points of electrical activity of the heart. 

The QT interval covers the mechanical contraction of the heart's ventricles. It encompasses the period where the ventricles depolarize and then repolarize. 

The QT interval is of importance because anything that makes the QT any longer than it normally is can predispose the heart to Torsades de pointes --> ventricular arrhythmias. Also, arrhythmia is hard to spell. 

Class IA and Class III antiarrhythmics prolong the QT interval by blocking the potassium (K+) channels (makes phase 3 of the pacemaker action potential longer). 

Class IA: Na+ blockers: Quinidine, Procainamide, Disopyramide

Class III: K+ blockers: Sotalol, Dofetilide, Ibutilide, Amiodarone, Dronedarone

Atherosclerosis: Fibrous Cap

One stylish-looking artery.

An atherosclerotic artery contains a core of cholesterol/cholesterol esters, macrophages filled with oxidated LDL --> low density lipoproteins (foam cells), and necrotic material (after the foam cells have died). Covering this core is a fibrous cap. The fibrous cap can rupture and release the central core of necrotic material into the artery, resulting in the formation of a thrombus. 

Extreme atherosclerosis is something you want to avoid; it's a shame that fattening foods taste so good.

Hemophilia

Poisoned, shot four times, beaten, and drowned.

Rasputin: what a legend. The fact (rumor?) that it took poison, multiple gunshots, and finally a little bit of drowning to successfully murder him makes him seem almost supernatural. (Hey, remember that animated Anastasia movie?)

But on a more relevant note, Rasputin was also known for his role as the "healer" of Alexei Nikolaevich, Tsarevich of Russia. Alexei suffered from hemophilia, which is a bleeding disorder. In fact, a couple of royal descendants of Queen Victoria were hemophiliacs (oh those silly inbreeders, not that I'm judging). There are a variety of hemophilia disorders, but the two types of most significance are hemophilias A and B. 

Hemophilia A (the most common hemophilia) is an X-linked recessive disorder resulting in a deficiency of Factor VIII in the coagulation cascade. 

Hemophilia B is an X-linked recessive disorder resulting in a deficiency of Factor IX in the coagulation cascade. The deficiencies in factors VIII and IX will contribute to ineffective formation of fibrin (= ineffective clotting). 

Note that a common complication of hemophilia is hemophilic arthropathy, where there is bleeding in the joints that may result in joint deformities if left untreated. 

Astrocytes

It's a-me, Mario!

Yeah, I drew Mario to look a bit like Luigi...

But anyway, astrocytes are cells that have a star-like shape. They are found in the central nervous system and perform a variety of functions, including metabolic support to other brain cells and the metabolism of neurotransmitters. Astrocytes will proliferate under injury to form glial scars (gliosis).

Astrocytomas (a form of brain tumor) has three grades: I, II, and III. Grade III tumors show increased cellularity, distinct nuclear atypia, and marked mitotic activity. These tumors will also enhance on imaging studies.

You can stain astrocytes with GFAP (glial fibrillary acidic protein).

Granulocyte Development: Band Forms

Who remembers Planter's Cheez Balls?

Band forms: these are the cells that are one step away from differentiating into neutrophils. Compared to neutrophils (which typically have a multi-lobed nucleus), band forms have a nucleus that is more horse-shoe shaped. (I think they look more cashew/peanut shaped though, hence the Planter's peanuts nucleus). Band forms may increase in the presence of an infection. 

The development of granulocytes (note that they all contain granules!) follows this order:

Myeloblasts
Promyelocytes
Myelocytes
Metamyelocyte
Band form
Neutrophil

A mnemonic for granulocyte development: Mother, Please Make My Bed.

Anichkov Myocyte - Acute Rheumatic Fever

Needed an excuse to draw an AK47. Pew pew pew.

Some people describe these Anichkov myocytes to look like caterpillars, but I don't really see the resemblance. Anichkov (and probably any other Russian-ish name) does bring to mind the image of a Kalashnikov, so I threw that in for kicks!

Anichkov myocytes are found within fibrinoid/collagenous lesions caused by rheumatic fever. These lesions are known as Aschoff bodies. Acute rheumatic fever most often involves pancarditis or myocarditis resulting in mitral insufficiency. In chronic rheumatic fever, the mitral valve (causing either mitral stenosis or insufficiency) and aortic valve (causing either aortic stenosis or aortic regurgitation) can be involved.

Rheumatic fever occurs after an infection with Group A β-hemolytic streptococci. How can you tell if a certain strain of streptococci is β-hemolytic? Culture it on a blood agar plate and β-hemolytic cells should lyse the RBCs.

Hemolytic Uremic Syndrome (HUS)

HAMBOIGER

This was supposed to be a play on Pizza Hut --> Burger Hut --> Burger HUS? The attempt to be somewhat clever falls flat. 

ANYWAY: Hemolytic Uremic Syndome (HUS) presents as a triad of symptoms including hemolytic anemia, renal failure, and thrombocytopenia. Childhood-type HUS is associated with Escherichia coli O157:H7 (a gram negative rod that that expresses a Shiga-like toxin). Try not to eat undercooked hamburgers if you can!

FYI: HUS is classified as a thrombotic microangiopathy. Also, I'm probably wrong about E. coli being flagellated.

     

Auer Rods - Acute Myelogenous Leukemia - Part 2

Tick tock

More AML fun facts!

Cytogenetic abnormalities in AML may include t(8;21), inv(16), t(15;17), and monosomies/deletions in chromosomes 5 and 7. 

t(15;17) is associated with PML (acute promyelocytic leukemia) where there is a fusion of the PML protein with retinoic acid receptor-α (RARα). Remember to treat with ATRA. 

AML can also develop secondarily after treatment with topisomerase II inhibitors. This can result in MLL gene rearrangements on chromosome 11q23.

Auer Rods - Acute Myelogenous Leukemia - Part 1

LOL ROFLMAO BBQ WTF?

Auer rods: azurophilic needles/rods in myeloblasts. Seen in Acute Myelogenous Leukemia (AML).

AML is diagnosed when there are >20% blasts in the bone marrow.

Click here for a little more information on FML.

Reed Sternberg Cell - Hodgkin's Lymphoma

Hoot Hoot!

Reed Sternberg cell: giant B-lymphocyte-derived cells that have an owl's eye appearance. Found in Hodgkin's Lymphoma. 

Remember: they're CD15 and CD30 positive