NEET MDS Shorts
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NEETMDSMumps is a viral disease that commonly affects children and typically occurs only once in a lifetime, conferring lifelong immunity. It is known for causing painful swelling of the salivary glands, particularly the parotid glands.
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RadiologyIntensifying screen is used in extraoral radiographs to decrease patient radiation.
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Oral PathologyVitamin A deficiency is associated with hyperplasia and keratinization of the salivary glands.
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Dental Materials
The average depth of corrosion for most amalgam alloys is 100 to 500 µm.
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Oral medicineRecurrent sinusitis is due to both anatomical abnormalities and poor resistance. Anatomical factors like deviated nasal septum, polyps, or narrow ostia predispose to infection. Poor immune resistance, allergies, or systemic conditions also contribute to recurrent episodes.
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RadiologyThe technique employed in radiotherapy to counteract the effect of tumour motion due to breathing is known as gating.
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Pathology
The first vascular reaction in inflammation is Vasodilation.
Explanation:
Inflammation is the body's protective response to tissue injury or infection. It
is characterized by the classical signs of redness (rubor), heat (calor),
swelling (tumor), pain (dolor), and loss of function (functio laesa). The
initial vascular changes in the inflammatory process include:
1. Vasoconstriction: This is a temporary response that occurs immediately after
injury to minimize blood loss. However, it is quickly followed by the more
significant and prolonged phase of vasodilation.
2. Vasodilation: This is the first major vascular reaction in the inflammatory
response. Vasodilation occurs due to the release of substances such as
histamine, bradykinins, and prostaglandins from the damaged tissue cells and
mast cells. These substances are known as vasodilators and they cause the smooth
muscles surrounding the blood vessels to relax, leading to an increase in the
diameter of the blood vessels. This results in increased blood flow to the
injured area, which is essential for delivering white blood cells, nutrients,
and oxygen to the site of inflammation. The increased blood flow is what causes
the characteristic redness and heat of an inflamed area.
3. Increased vascular permeability: Although it is not the first vascular
reaction, increased vascular permeability is a critical component of the
inflammatory process. After vasodilation, the endothelial cells that line the
blood vessels become more permeable, allowing plasma and proteins to leak out of
the vessels into the surrounding tissue. This leads to the formation of an
exudate, which is the accumulation of fluid and proteins that makes up the
swelling (edema) seen in inflammation.
4. Marginisation or Pavementing: This is the process where neutrophils (a type
of white blood cell) move along the walls of blood vessels towards the site of
inflammation. It occurs later in the inflammatory response after the initial
vasodilation and increased vascular permeability. These cells then migrate
through the vessel walls into the tissue to combat pathogens and debris.
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Biochemistry
Epinephrine, also known as adrenaline, is a hormone and neurotransmitter that
is synthesized in the body from the amino acid tyrosine. Tyrosine is a
non-essential amino acid, which means that it can be synthesized in the body
from phenylalanine, another essential amino acid. The synthesis of epinephrine
occurs in two main steps:
1. Hydroxylation of tyrosine: Tyrosine is converted into dihydroxyphenylalanine
(DOPA) by the enzyme tyrosine hydroxylase. This is the rate-limiting step in the
synthesis of epinephrine.
2. Decarboxylation and further hydroxylation: DOPA is then decarboxylated to
form dopamine, which is further hydroxylated to produce norepinephrine.
Norepinephrine is the immediate precursor of epinephrine.
3. Formation of epinephrine: Norepinephrine is methylated by the enzyme
phenylethanolamine N-methyltransferase (PNMT) and converted into epinephrine.
The other amino acids listed are not directly involved in the synthesis of
epinephrine:
1. Valine and Leucine are branched-chain amino acids that are primarily involved
in the metabolism of muscles and energy production.
2. Cysteine is a sulfur-containing amino acid that is important for the
synthesis of proteins with disulfide bridges and is a precursor for other
molecules like glutathione and taurine, but not directly involved in the
synthesis of epinephrine.
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General Medicine
In a patient with sickle cell anemia and symptoms of biliary colic, the most likely diagnosis is cholelithiasis due to the increased incidence of gallstone formation in this population. Initial management should focus on hydration and pain relief with analgesics, as surgery is typically reserved for cases of cholecystitis or pancreatitis.
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EndodonticsVertical root fractures are often associated with a poor prognosis because they can lead to significant loss of tooth structure and are difficult to treat. They typically result in the need for extraction, especially if they extend into the periodontal ligament or if the fracture is not detected early.