A Fib =  No P Wave 

One possible cover design for The Book

Coming soon.

Colon: pseudomembranous colitis due to Clostridium difficile (pseudomembranous inflammation) Note the gray-yellow pseudomembrane covering the entire mucosal surface. Damage is due to a toxin produced by C. difficile. Similar to diphtheria, the toxin produces necrosis of the mucosa and submucosa without actual invasion by the bacteria. A toxin assay of stool is the best method for diagnosing the disease. Ampicillin is the MC drug causing pseudomembranous colitis and does so by destroying colonic bacteria that normally keep C. difficile in check.

Haematology

White Blood Cells (Leukocytes)

Neutrophils, eosinophils and basophils = granulocytes (polymorphonuclear leukocytes)

Monocytes & lymphocyes = mononuclear

Neutrophils

Most numerous (~60% of WBC)

Nucleus divided into lobes

Cytoplasm contains small granules

Stains pink with Romanowsky dyes

Lifespan of 6-10hrs

Exit into tissues - non-specific defence against bacteria and fungi

Eosinophils

1% of circulating leukocytes 

Large cytoplasmic granules - stain strongly with acidic dye eosin

Nucleus is bilobed

Circulate for 4-5hrs

Exit to tissues –> 

Defence against parasites 

Dampen allergic response

Tissue eosinophils are also capable of responding to bacterial and fungal infection in a similar way to neutrophils.

Basophils

Least numerous (<1%)

Large granules stain strongly with basic dye methylene blue

Involved in anaphylactic hypersensitivity and inflammatory reactions

Monocytes

5% of circulating leukocytes

Large cell

Kidney/clefted shaped nucleus

Scattering of delicate azurophilic granules

Circulate for 10hrs

Mature into phagocytic tissue macrophages

Responsible for the removal of aged RBCs and other debris

Process and present antigens to T-lymphocytes 

(Macrophages are formed in response to an infection or accumulating damaged or dead cells. Large, specialized cells that recognize, engulf and destroy target cells.)

Lymphocytes

Second most common leukocyte (33%)

Much less cytoplasm - nucleus almost fills cell

Variable lifespan

Receptors on surface recognise foreign substances

Several types of lymphocyte - click here

ETC shortcuts

FADH2 goes to complex II since 2 hydrogens

RotenONE inhibits complex ONE

AntImIcIn A, 3 III’s ==> Antimycin A inhibits complex 3

Cyan COlored Complex IV ==> Cyanide and CO inhibit complex IV

24 brown fatty aspirins break up ==> 2,4 dnp, aspirin and brown fat are etc uncouplers 

Antimicrobial Agents - Inhibition of DNA and Protein Synthesis

Bacterial chromosome replication

DNA replication

Bacterial Topoisomerases 

maintain DNA in appropriate state of supercoiling 

cut and reseal DNA

DNA gyrase (topoisomerase II) introduces negative supercoils 

Topoisomerase IV decatenates circular chromosomes 

these are the targets of the quinolone antibacterial agents 

Quinolones

bind to bacterial DNA gyrase and topoisomerase IV after DNA strand breakage 

prevent resealing of DNA 

disrupt DNA replication and repair 

bactericidal (kill bacteria)

Fluoroquinolone is particularly useful against

Gram +ves: Staphylococcus aureus, streptococci 

Gram -ves: Enterobacteriacea; Pseudomonas aeruginosa 

Anaerobes: e.g. Bacteroides fragilis 

many applications e.g. UTIs, prostatitis, gastroenteritis, STIs 

Adverse effects

Relatively well tolerated

GI upset in ~ 5% of patients 

allergic reactions (rash, photosensitivity) in 1 - 2% of patients 

Inhibition of Bacterial Protein Synthesis 

Macrolides 

in 1952: Erythromycin was isolated as the first macrolide (Streptomyces erythreus) 

Newer macrolides: clarithromycin, azithromycin 

Structurally they consist of a lactone ring (14- to 16-membered) + two attached deoxy sugars 

Mode of action 

bind reversibly to bacterial 50S ribosomal subunit 

causes growing peptide chain to dissociate from ribosome → inhibiting protein synthesis 

bacteriostatic (stops reproduction)

Macrolides’ spectrum of activity

good antistaphylococcal and antistreptococcal activity 

treatment of respiratory & soft tissue infections and sensitive intracellular pathogens • e.g. Chlamydia, Legionella 

Adverse effects

Generally well tolerated

nausea 

vomiting 

diarrhoea 

rash 

Aminoglycosides

large family of antibiotics produced by various species of Streptomyces (“mycin”) and Micromonospora (“micin”) 

include: streptomycin, neomycin, kanamycin, gentamicins, tobramycin 

Structure = linked ring system composed of aminosugars and an aminosubstituted cyclic polyalcohol 

Mode of action of aminoglycosides

Bind irreversibly to 30S ribosomal subunit 

disrupt elongation of nascent peptide chain 

translational inaccuracy → defective proteins 

bactericidal 

Spectrum of activity 

broad spectrum; mainly aerobic G-ve bacilli (e.g. P. aeruginosa) 

used to treat serious nosocomial infections (hospital acquired infections)

First TB antibiotic

Used for cystic fibrosis 

Adverse effects

all aminoglycosides have low Therapeutic Index (only a small amount needed to become toxic)

renal damage, ototoxicity, loss of balance, nausea 

Clostridium botulinum

Gram+, anaerobe, spore forming, motile rods

Botulin toxin (botox) inhibits the release of ACh and produces a flacid paralysis.

Adults ingest the toxin from poorly heated canned food (labile toxin, 60° 10minutes): weakness, diplopia, flacid paralysis and respiratory muscles involved, vomiting, diarrhea.

Infants ingest the spore from the dust or honey and form the toxins in the gut: constipation, weak crying, weak feeding, flacid paralysis and rapid respiratory involvement

Wound: traumatic implantation (assoc. w/ IVDA; uncommon), same symptoms without GI symptoms. Debridement, no closure.

Microbial Genetics

April Background

I created this new background for April! A reminder to all the great girls out there who are awesome human beings!

For a high quality foto, check out the link in my previous post!

05-11-18 bio notes! i tried out a new background and i think it looks really pretty!! i hope you guys like it :). i had my first test for my dissection lab and my group ended up getting 100%! the next few tests are harder, but i think we’ll all do gr8. i hope you all had a great week!

MICROBIOLOGY MNEMONIC

My favorite band: the Killers (and I’m gonna see them for the second time in 3 weeks!!!!!!! I’m SO excited!!!!!!)

There’s this mnemonic to remember encapsulated organisms that use capsule layers as their major mechanism of pathogenicity. 

Capsules are slippery layers and can not be phagocyte. To remember that, just remember this Killer’s song called “All the pretty faces”

This is the only way I can remember this mnemonic, here it goes…

S ome   K illers  H ave   P retty   N ice   Capsules

S treptococcus pneumoniae

K lebsiella pneumoniae

H aemophilus influenzae

P seudomona aeuroginosa

N eisseria meningitidis

C riptococcus neoformans