Enzymes and the Type of Reactions they Catalyze ( Part 6 : LIGASES)

Hello guys, we come to an end of this 6 part enzyme series and also this is the 500th Medicowesome post for 2016! Woohoo! :D

Ok, back to our business! Ligases, what to they do? Obvio, they LIGATE! Or simply connect! But connect what?

Think of these guys as a Plumber who connects those pipes! ;)

Major subclasses

• Synthetase - Formation of new bond between substrates using the energy from an ATP
• Synthase - Link two molecules without using the energy from ATP (Confusing with Synthetase? They use ATP. Check here for a memory aid.)
• Carboxylase - Formation of a new bond between a substrate and a CO2 using the energy from an ATP

Are we ok guys?

Jay  :) 

Enzymes and the Type of Reactions they Catalyze ( Part 5 : ISOMERASES)

Ok what are isomers? Same molecular Formula, different structure! That is an Isomer! And presumably isomerases play with these isomers. But how?

• Racemase - Conversion of D isomer to L isomer or vice versa(Read about them here more in IkaN's article)
• Mutase - Conversion of one constitutional isomer into another. They shift one functional group from one place to another place within the same molecule.

Are we clear on this? 

Jay :)

Enzymes and the Type of Reactions they Catalyze ( Part 4 : LYASES)

With part 4 we come to a little confusing group of Enzymes guys! LYASES! They are called Lyases, of course because they do Lyse! :P

ok the major subclasses?

• Dehydratase - Removal of H2O from a substrate (Confusing with Dehydrogenase?Read Part1)
• Decarboxylase - Removal of CO2 from a substrate
• Deaminase - Removal of NH3 from a substrate
• HYDRATASE - ADDING of H2O to a substrate
• Aldolase - Produces Aldehydes via elimination reactions

Any questions guys? :)

Jay

Enzymes and the Type of Reactions they Catalyze ( Part 3 : HYDROLASES)

Back with Part 3 guys! It's Jay with Hydrolases! :P

There are 5 major classes of Hydrolases. They always Hydrolyse means breaking it down with the help of H2O.

• Lipase - Hydrolysis of ESTER linkages of lipids
• Protease - Hydrolysis of AMIDE linkages of proteins
• Nuclease - Hydrolysis of SUGAR PHOSPHATE ESTER linkages of Nucleic Acids. Phosphodiesterases also do the same
• Carbohydrase - Hydrolysis of GLYCOSIDIC bonds of Carbohydrates
• Phosphatase - Hydrolysis of PHOSPHATE ESTER bonds.

Also please note, that the types of bonds in CAPITAL ITALICIZED letters are the major types of bonds in those biomolecules as well as the bonds that break due to these enzymes.

Jay :)

Enzymes and the Type of Reactions they Catalyze ( Part 2 : TRANSFERASES)

Hey guys, Jay here once again with Part 2. Here we will talk about Transferases!

Transferases, do Transfer! But transfer what? There are two major types of Transferases!

• Transaminase --> Transfer of an Amino group between substrates
• Kinases --> Transfer of a Phosphate group between substrates often from ATP
• Methyltranferase --> Tranfers single-carbon units between substrates
• Phosphorylase -->Transfers inorganic phosphate to a substrate

Trivia!

What does Kinase even mean? It comes from the greek work Kinein means "To move". It originally had nothing to do with Phosphates. But now we almost exclusively use this for Phosphate transfers. :)

Jay :)

Enzymes and the Type of Reactions they Catalyze ( Part 1 : OXIDOREDUCTASES)

Guys the post is quite long. So I thought to break it into 6 different parts. This post will cover Oxidoreductases.

There are 5 main types of Enzymes in this category. As the name suggests, two of them are Oxidases and Reductases. The other ones are Dehydrogenases, Oxygenases and Peroxidases.

• Oxidases --> Oxidizes a substrate
• Reductases --> Reduces a substrate
• Dehydrogenases --> A double bond is introduced to the substrate, by removal of two H atoms. The H are accepted by a Coenzyme.
• Oxygenase --> Directly incorporates Oxygen into the substrate
• Peroxidase --> Uses Hydrogen Peroxide H2O2 as an electrone acceptor

Question? Yes! Removal of Hydrogen and adding of Oxygen are also considered a type of Oxidation because it increases the oxidation number of the substrate! Pre-Med Organic Chemistry anyone? ;)

See you soon with the other categories guys!

Jay :)

P.S. - Don't confuse Dehydrogenase with Dehydratase!!! We go through that here:)

Urgent vs. Emergent Tracheostomy

In English, Urgency and Emergency almost means the same. But when it comes to Medical literature, it has a little difference.

So what are the differences of Urgent and Emergent Tracheostomy?

Night terrors vs Nightmares

Hey awesomites!

People who have night terrors are often misdiagnosed, nightmares being the most common. Post traumatic stress disorder is another common misdiagnosis (in adults).

Here's the difference between night tremors and nightmares both of these are classified under a group of disorders, the Parasomnias!

Recent research suggests that getting an extra sleep for 30- 40 minutes a night reduces both nightmares and night terrors to a great extent.

Scheduled awakening therapy-
Another treatment strategy (for night terror) is "Scheduled awakening therapy". It involves waking the person from sleep 15- 30 minutes before the episodes typically occur so that the cycle is interrupted and prevent the onset of the night terror. But the child is not to be fully awaken in the middle of the night.
Thats where the idea of sleep guardian came from. The sleep guardian plans smartly and finds a right time to partially wake up the child and vibrate each night (for less than 3 minutes). This prevents the episode of night terrors and sleep is not actually totally disturbed.
This method of prevention of night terrors has shown 90% positive results within first week with 80% fewer night terrors after four weeks of use.

Thats all
- Jaskunwar Singh

Adamantinoma

Hello awesome people !
Today's topic is - ADAMANTINOMA ! (and no it's not what would only happen to Wolverine! Haha see what I did there ?! )

1)Also known as Ameloblastoma (Ameloblasts are enamel forming cells), Eve's disease (looks like ADAM & EVE had a tiff over who'd name it, and clearly it was a draw! :p)

2) Its a benign tumor, but behaves like a malignant one, it metastasizes to lungs. (so wanna be)

3) Sites : #Mandible (most common site) (anyone else going weak in the knees seeing Hugh Jackman's jawline?, cool now you'll remember it better!)
Talking of knees, #Tibia is the 2nd most common site !
#Pituitary because the stalk of pituitary and enamel arise from oral epithelium

3) Slow growing tumor, with multiple cystic spaces...patients often complain of falling teeth or fracture mandible :(

4) X ray shows a "Honeycomb" appearence

5) Treatment? Well since this tumor is very "Adamant" simple curettage will cause recurrence, hence we do a wide excision (1cm margin)...Sometimes a Hemimandibulectomy may have to be done! (Sounds like what Wolverine would do to his enemies!)
All the Wolverine fans put your hands up and read this again !!  :p
That's about it !!
-PP

Top 10 series: Phenytoin

Hello!

Here are top 10 facts about of phenytoin.

Ulnar nerve

Ulnar nerve
Nerve root :C7-T1.
Key points :
On the back of medial epicondyle of humerus ulnar nerve can be palatable it produces tingling sensations Hence humerus is called as "Funny bone".
Ulnar nerve is not a content of Cubital fossa .
Remember:Ulnar nerve supplies total 15 muscles  in hand!
 
3 hypothenar eminence ,medial 2 lumbricals ,4 dorsal and 4 Palmer interossei and ADDuctor pollicis
Palmaris brevis
Forearm(Read carefully don't get confused)
Medial half of flexor digitorum profundus(Thinking about lateral half ??!!! Well ,it is supplied by Median nerve )
Flexor carpi ulnaris (Thinking about extensor carpi ulnaris ?! Read  carefully ,Supplied by radial nerve)
Clinical anatomy:
1)Musician nerve
2)Ulnar nerve lesion at the wrist :Ulnar claw hand which shows
a)Hyperextension at metacarpophalangeal joints and flexion at the interphalangeal joints ,involving ring and little fingers (Little finger is held in extension by extensor muscles )
b)Sensory loss is confined to the medial one third of the palm and medial one and a half fingers including nail bed .Medial half of dorsum of hands also shows Sensor loss
c)Vasomotor changes :Skin is warmer due to arteriolar dilation ,it is also drier due to absence of sweating because of loss of sympathetic supply.
d)Trophic changes:Long standing cases of paralysis lead to dry and scaly skin .The nails crack easily
It should be noted that median nerve lesions are more disabling.In contrast ,Ulnar nerve lesions leave a relatively efficient hand

Principal cell: How to remember it's function and location in the nephron

Principal cell

Top 10 series: Cyclophosphamide

And here's A. P. Burkholderias fav drug - Cyclophosphamide!

ENT instruments contents page

Hey, so because the contents page has expanded so much, I thought of making sub sections within the contents page for a few topics.

Here's the mini contents page for ENT instruments, this post is linked to the main contents page :)

Top 10 series: Rifampicin

Introducing a new series of videos :D

Hope you like them!

Chronic complications of pulmonary tuberculosis mnemonic

Chronic complications of pulmonary tuberculosis

Pulmonary complications-  HE CAL BOB
H- Haemoptysis
E- Emphysema
C- Cor pulmonale
A- Aspergilloma/ Atypical MTB
L- Lung calcification
B- Bronchiectasis
O- Obstructive pulmonary disease
B- Bronchopleural fistula

Extra- pulmonary complications- PALE
P- Poncet's polyarthritis
A- Anorectal fistula/ Amyloidosis
L- Laryngitis
E- Empyema necessitans/ Enteritis


Thats all
- Jaskunwar Singh

Herpes Zoster Ophthalmicus notes

Herpes zoster ophthalmicus

This viral infection is associated with a previous childhood exposure to varicella zoster (chickenpox) which remains hidden within and becomes active later in life when immune functions of the body weaken.

GUYS, did you check First Aid 2017? We are Super Proud of you IkaN!!!

Beloved Awesomites, I have a super-awesome announcement to make today regarding our Founder IkaN aka Nakeya Khozema Dewaswala.

She is the Image and Illustration editor in the recently released world famous medical book, First Aid 2017!!!

We are super proud of you sis, especially you being the only representative from South Asia in the book for this edition! We always knew you are an amazing medical student, but you proved you are totally exceptional with this feat.

This is another step toward your success sis. You are an inspiration to thousands and thousands of medical students around the world, and a living proof that if you want something, and if you struggle for it, you will certainly get it!

Me, myself am so lucky to have known you personally and be called as your bro, and I know, more than you have an AWESOME brain, you have an AWESOME heart! (Isn’t this why we love her a lot, Awesomites?)

Keep inspiring us sis! We at the Author Panel of Medicowesome, and the whole thousands of Medicowesome members, would like to congratulate you, and wish you all the very best in your all future endeavors!

Yours,

Jay :) 

On behalf of the Author Panel of Medicowesome

P.S. - Special thanks to Krupal Patel in Medicowesome Whatsapp group who brought picture to our attention! :) 

Restless leg syndrome notes

RLS symptoms:
Urge to move legs
Symptoms begin with rest
Relief on movement

Associated with:
Anemia
Pregnancy
Renal failure
Peripheral neuropathy

Pathogenesis:
Disordered dopamine function in association with abnormal iron metabolism

Treatment:
Sleep hygiene
Pramipexole, ropinirole
Iron for IDA

That's all!
-IkaN

Membranous and pseudo-membranous conjunctivitis notes

Pseudo-membranous conjunctivitis: mild form
Membranous conjunctivitis: severe form

Causative agents:
Corynebacterium diphtheriae
Beta- hemolytic streptococci
Streptococcus pneumoniae
Neisseria gonorrheae

Associated conditions:
Erythema multiforme
Stevens- Johnson syndrome

Pseudomembranous:
- Lid swelling
- mucopurulent bloody discharge
- white membrane
- easily peel off without bleeding

Membranous:
- Lids are hardened
- semisolid exudates: result in necrosis of conjunctiva and cornea
- difficult to peel off
- associated with bleeding from the undersurface

Important points to be noted:-
- The membrane forms more commonly over palpebral conjunctiva beginning from the edge of lid.
- There is enlarged preauricular lymph nodes with suppurative discharge.
- Marginal corneal ulcer due to secondary infection (especially streptococci).
- high risk of symblephron (adhesion between palpebral and bulbar conjunctiva)

Treatment:
- Penicillin (10,000 units/ ml) is the doc for acute diphtherial infection. Systemic administration and a quick injection of anti- diphtheritic serum (4,000- 10,000 units BD) 
- Removal of the membranes is not advised because of the risk of adhesion (symblephron).
- Local and systemic administration of bacitracin and penicillin is recommended in case of streptococcal infection.

Pseudotumor cerebri notes

Pseudotumor cerebri

Associated with:
Obesity
Vitamin A toxicity

Signs and symptoms:
Headache
Sixth nerve palsy
Visual field defects
Pulsutile tinnitus

Diagnosis:
Papilledema
To rule out space occupying lesions - CT / MRI normal
Most accurate - Lumbar puncture with opening CSF pressure measurement

Treatment:
Weight loss
Acetazolamide
Surgery

Why does increased ICP cause 6th nerve (Abducens) palsy?
Increased ICP can result in downward displacement of the brainstem, causing stretching of the sixth nerve secondary to its location within  Dorello's canal.

That's all!
-IkaN