Interglobular Dentin

• Sometimes mineralisation of Dentin begins in small globular areas that fail to fuse into the homogeneous mass. 
• It results in Zones of Hypomineralisation between globules. 
• Most commonly found in Circumpulpal Dentin which is present below the Mantle Dentin. 

In other words, in poorly formed teeth, due to deficiency of vitamin D or exposure to fluoride, it leads to defect in mineralization i.e. loss of globular dentin.

Note: Defect is not because of improper matrix formation.

Thought Question: Dentinal tubules pass uninterruptedly through Globular Dentin. Why? Comment your answers!

- Written by Anisha Valli

Leech therapy for venous congestion

Today, I came to know that leeches are a well-recognized treatment for congested tissue :O

When this image was sent to me, I thought it was an infestation. After reading about it though, it was clarified that the leech was put deliberately by the plastic surgeons to treat venous congestion (hirudotherapy). 

Authors' diary: Life support

AML and ALL differentiating features.

Hello awesomeites !

Today let us find out the difference between AML and ALL on the basis of cell morphology, cytochemistry and immunophenotyping.

So, Acute Leukemia is the presence of blasts >=20% either in peripheral blood or bone marrow.

Myeloblasts in AML and Lymphoblasts in ALL are the two main types. 

Cell morphology:

Myeloblasts:  The characteristic feature is the presence of Auer rods with moderate amount of cytoplasm and cytoplasmic granules and multiple nucleoli

Lymphoblasts:  They have a scanty cytoplasm no granules and nucleoli are not present

Many a times differentiating the two on morphological basis isn’t feasible. So we take the help of cytochemistry.

Cytochemistry:

Myeloblasts:  are myeloperoxidase(MPO) and Sudan black B (SBB) positive

                         Monoblasts which are a part of the myeloid lineage are nonspecific esterase (NSE) positive

Lymphoblasts:  are periodic acid Schiff (PAS) positive

MPO stains the enzyme within the azurophilic granules and is the most specific while SBB stains the lipid membrane of the azurophilic granules and is most sensitive for myeloid differentiation .

Even after this if we aren’t able to differentiate then we take the help of immunophenotyping

 
Immunophenotyping:

It is performed by flow cytometry.

The sample either bone marrow or peripheral blood is stained with antibodies and the cells are allowed to fall freely in a single file across a beam of laser (this is the over simplified version of it :P).

The laser used is Blue laser of wavelength 488nm. When the laser beam hits the cells some of it gets scattered to the sides and is known as the side scatter which is a measure if the granularity of the cells. While the rest of the beams travel in the same line without deviation and is called as the forward scatter and is a measure of the size of the cells.

Neutrophils are the cells with the highest side scatter.

Staining of the cells with antibodies helps in subtyping acute leukemias on the basis of CD markers.

Here is a list of CD markers on varies cells of myeloid and lymphoid lineage

B cell markers:

CD19: present on all B cells

CD10: immature B cells

CD20: mature B cells

T cell markers:

CD3: present on all T cells

CD4 CD8 CD2 CD5 CD7 are some of the other markers present on various T cells

Myeloid markers: CD13 CD33 CD117

Stem cell markers: CD34

Monocyte markers: CD14 CD64

NK cell markers: CD16 CD56

CD45 is present on all leucocytes a.k.a pan leucocyte marker 

That’s all for now, hope this helps in better understanding of AML and ALL!

Keep calm and keep studying!

Stay awesome!

-          Ashish G. Gokhale

AFASS criteria

Hello Awesomites ! :D

AFASS CRIETRIA is used to decide whether a HIV positive mother can breast feed or not provided that she has not started top feed yet.
(Why? Once the mother started to top feed the child, this criteria is not used. HIV positive mother in such case should continue top feed. Because mixed kind of feed is more dangerous than top feed alone)

Acceptable: The mother perceives no problem in replacement feeding. Potential problems may be cultural, social, or due to fear of stigma and discrimination.

Feasible: The mother (or family) has adequate time, knowledge, skills, resources and support to correctly mix formula or milk and feed the infant up to 12 times in 24 hours.

Affordable: The mother and family, with community or health system support if necessary, can pay the cost of replacement feeding without harming the health or nutrition status of the family.

Sustainable: Availability of a continuous supply of all ingredients needed for safe replacement feeding for up to one year of age or longer.

Safe: Replacement foods are correctly and hygienically prepared and stored, and fed preferably by cup.

Source: http://motherchildnutrition.org/info/afass-principles.html (Click to know what all questions are asked)

-Upasana Y.:)

Inguinal lymph nodes

Hello Awesomites! :)

Long time. Happy to be back. :D

Today we will study Inguinal Lymph nodes along with its clinical significance.

You know fascia lata is present in our lower limbs.

The Lymph nodes lying above it is called as superficial inguinal Lymph nodes.

The Lymph nodes lying beneath it is called as deep inguinal Lymph nodes.

The superficial Lymph nodes are further divided into horizontal and vertical groups.

The deep lymph nodes are deep to fascia lata and 1-2 nodes can be found in femoral canal. This nodes in the femoral canal are called as deep inguinal Lymph node of Rosenmuller or of Cloquet. This drains glans penis and clitoris.

Through the umbilicus is taken a watershed line of Lymphatic drainage of anterior abdominal wall.

The anterior abdominal wall below the umbilicus drains in the superficial inguinal lymph nodes.

Entire perineum except glans penis and glans clitoris are drained by superficial lymph nodes.
Most of the lower limb is drained by superficial inguinal lymph nodes except the territory of short saphenous vein (This part of lower limb is drained by popliteal group of lymph nodes).

Some part of Uterus and uterine tubes are also drained by superficial inguinal lymph nodes.

Anal canal below pectinate line also drains in superficial inguinal lymph nodes.

Superficial Inguinal lymph node drain lymph from the

1.     gluteal region,

2.      inferior anterior abdominal wall,

3.      perineum

4.     superficial lower limbs

5.     Anal canal below pectinate line

Deep Inguinal Lymph node drains

1.     deep lymphatics of the distal lower extremity

2.      perineum (e.g. glans penis / clitoris),

CLINICAL SIGNIFICANCE:

In sexually transmitted diseases, you will find enlargement of this lymph nodes.
Inguinal lymph nodes are the frequent sites of metastasis for malignant lymphoma, squamous cell carcinoma of anal canal, vulva and penis, malignant melanoma and squamous cell carcinoma of skin over lower extremities or trunk. 

-Upasana Y. :)

Allergic Broncho-Pulmonary Aspergillosis (ABPA) treatment mnemonic

To remember that Allergic Broncho-Pulmonary Aspergillosis is treated by corticosteroids mainly and not anti-fungals although Aspergillus is a fungus, just write:

Allergic Broncho- Pulmonary Aspergillosis ==> as => Allergic BronC-Orticosteroids Pulmonary Aspergillosis

and that's it :)

-Murad

Query on Step 2 CS deadline & match timeline

I read this link and I'm confused, it says:

To participate in the National Resident Matching Program® (NRMP®) Main Residency Match®, international medical students/graduates must have passed all exams required for ECFMG Certification. If you plan to participate in the 2019 Match (in March 2019) and still need to pass Step 2 Clinical Skills (CS), you should register now to take the examination.

To help ensure that your result will be available in time to participate in the 2019 Match, you must take Step 2 CS by December 31, 2018. If you do not register now and schedule soon, it is possible that you will not be able to obtain a test date in 2018. At the time of this writing, the earliest available test date at any test center is in August 2018.

Link: April 2018 https://www.ecfmg.org/news/2018/04/09/imgs-participating-in-2019-match-should-apply-for-step-2-cs-now/

I plan to apply for matching in 2019, do I need to take the exam in December 2018?

- Sent through email

Hello,

Let me clear terminologies before I start explaining.

Match 2018 means: Application in September 2017, results in March 2018, Residency starts in July 2018.

You said apply for matching in 2019, which means apply in September 2019 for the March 2020 match, yes?

Let's talk about the 2019 match mentioned in the link you sent. It says currently, there will be no availability of testing centres for this year's match (September 2018 application, March 2019 Match, Residency starts in July 2019). The ECFMG website is able to predict the number of applications that they are going to receive. This year, they predict there will be no testing centers available, which is why I am guessing they are asking you to register in April (register now).

Your confusion arises because of two reasons:
You don't know the match terminologies with respect to the year.
You don't know the timeline for the match.

When they mean apply right now and give the exam before December, they are talking as a general mandatory requirement. IT IS A ABSOLUTE MUST HAVE.

To be a competitive candidate, IMGs tend to give the exam in such a way that the results are out before September so that we have all the exam results before the application cycle of the match. IT IS OPTIONAL BUT PREFERRED.

So really, the virtual deadline to give the exam for us is July. We also prefer to graduate before September to get ECFMG certified, however, it's not mandatory.

It is quite vigilant of you to keep an eye out for these notices on the ECFMG website.

Since the dates are not easily available, when you plan to go for an elective, try to register in advance.

If you go to the ECFMG website, there is a site called a step 2 CS scheduling and you can view the dates available at various centres. So register as soon as possible if you want to get your desired dates. Here's the link https://csess2.ecfmg.org/calendar.aspx

PS: The step 2 CS permit is available for one year and it does not expire quickly (compared to other exam permits that expire in 3 months) which is a huge advantage.

So to summarize, July is the ideal deadline for Step 2 CS to get results before September (Application submission). December is the mandatory deadline to get result before February (ROL submission, to be eligible for the match).

Google the step 2 CS reporting schedule to help plan for your match.
https://www.ecfmg.org/news/2018/04/18/results-reporting-schedule-for-step-2-cs/

Hope that helps!

-IkaN

Enamel Rods

• An enamel rod is the basic unit of tooth enamel. 
• Measuring 4 μm wide to 8 μm high, 
• An enamel rod is a tightly packed, highly organized mass of hydroxyapatite crystals
• It provides rigidity to the rods and strengthens the enamel.
• Enamel rods normally have a clear crystalline structure
• Light can pass through rods
• Many rods have a fish scale appearance
• Shape: Hexagonal
• Pattern: Keyhole or paddle-shaped prism pattern

Number: 

• 5 million= mandibular lower incisor to
• 12 million= maxillary first molar

The direction of rods:

• Rods are rarely straight, they follow a wavy course from dentin to the enamel surface
• Generally, they are oriented at the right angles to Dentin surface 
• Horizontal direction in the cervical and central part of the Crown
• Oblique to vertical direction in the incisal regions

Striations: 

• Rods are built up of segments separated by Dark Line in a rhythmic manner
• Visible by the action of mild acids
• Striations are uniform of 4 centimetre

- Written by Anisha Valli

Hertwig's Epithelial Root Sheath- HERS

Hertwig's epithelial root sheath

• It originates from the cervical portion of the enamel organ.
• It plays an important role in determining shape length size and number of roots.
• It is a double layer of cells which consists of outer enamel epithelium and inner enamel epithelium.
• Root sheath extends around dental papilla and separates it from surrounding dental follicle all through except the Basil portion.
• Inner enamel epithelial layer of root sheath influences the formation of odontoblast from the outer portion of the radicular dental papilla. 
• These odontoblasts lead to the formation of the first layer of radicular dentin.

As the first layer of radicular dentin is laid down:

• HERS loses its continuity 
• The cells of the dental follicle or dental sac invade double layer of HERS 
• Root sheath degenerates to form epithelial Islands

Therefore, it allows connective tissue of dental follicle to come in contact with newly formed radicular dentin. 

This causes differentiation of cementoblast from dental follicle which deposits cementum on newly formed radicular dentin.

Transitory Sutures

Transitory Sutures are found in cap stage of tooth development

Enamel Knot: Enamel organ cells form a knob-like extension which extends to the underlying dental papilla.

Enamel cord: it is a vertical extension of enamel knot

Enamel septum: when enamel cord extends to meet outer enamel epithelium it divides stellate reticulum into two parts

Enamel navel: Depression present at the junction of enamel septum and Outer enamel epithelium is known as enamel navel and it resembles umbilicus

Enamel Knot signals determine the shape of the tooth
Enamel Knot and Enamel cord act as a reservoir of dividing cells 

- Written By Anisha Valli

Human Papilloma Virus mnemonics

To remember that HPV vaccination starts at 11 years old and that HPV is the most common STD in the US, use the following mnemonics:

=> Write Human Papilloma Virus with 11 instead of the 2 Ls so it becomes as follows:
Human Papi11oma Virus

the 11 in papilloma will remind you of number 11 :)

=> remember HPV as the Highest Prevalent Virus :P
so this will remind you that it is the commonest STD

and that's it

-Murad

MDMA mnemonic

Hello! 

This post is about MDMA.

MDMA? Yep. It's short for 3,4-methylenedioxymethamphetamine.

Commonly called “Molly” or “ecstasy”.

MDMA can elicit feelings of euphoria, wakefulness, intimacy, and disinhibition.

Intoxication causes dangerous side effects such as:

Hypertension
Hyperthermia
Delirium
Psychomotor agitation
Hyponatremia
Intracranial hemorrhage
Myocardial infarction
Aortic dissection
Disseminated intravascular coagulation
Rhabdomyolysis
Seizures
Serotonin syndrome

Here's a mnemonic!

That's all!

-IkaN