NEET MDS Synopsis
Acne vulgaris
General Pathology
Acne vulgaris is a chronic inflammatory disorder usually present in the late teenage years characterized by comedones, papules, nodules, and cysts.
- subdivided into obstructive type with closed comedones (whiteheads) and open comedones (blackheads) and the inflammatory type consisting of papules, pustules, nodules, cysts and scars.
- pathogenesis of inflammatory acne relates to blockage of the hair follicle with keratin and sebaceous secretions, which are acted upon by Propionibacterium acnes (anaerobe) that causes the release of irritating fatty acids resulting in an inflammatory response.
- pathogenesis of the obstructive type (comedones) is related to plugging of the outlet of a hair follicle by keratin debris.
- chocolate, shellfish, nuts iodized salt do not aggravate acne.
- obstructive type is best treated with benzoyl peroxide and triretnoin (vitamin A acid)
- treatment of inflammatory type is the above plus antibiotics (topical and/or systemic; erythromycin, tetracycline, clindamycin).
Fatty Acid Synthesis
Biochemistry
The input to fatty acid synthesis is acetyl-CoA, which is carboxylated to malonyl-CoA.
The ATP-dependent carboxylation provides energy input. The CO2 is lost later during condensation with the growing fatty acid. The spontaneous decarboxylation drives the condensation.
fatty acid synthesis
acetyl-CoA + 7 malonyl-CoA + 14 NADPH → palmitate + 7 CO2 + 14 NADP+ + 8 CoA
ATP-dependent synthesis of malonate:
8 acetyl-CoA + 14 NADPH + 7 ATP → palmitate + 14 NADP+ + 8 CoA + 7 ADP + 7 Pi
Fatty acid synthesis occurs in the cytosol. Acetyl-CoA generated in the mitochondria is transported to the cytosol via a shuttle mechanism involving citrate
Acrylic Denture Bases
Dental Materials
Acrylic Denture Bases
Use - used to support artificial teeth
Classification
a. PMMA/MMA dough systems
b. PMMA/MMA pour resin systems
1. Components
a. Powder-PMMA polymer, peroxide initiator, and pigments
b. Liquid-MMA monomer, hydroquinone inhibitor, and cross-linking agents
2. Reaction
a. Heat (or chemicals) is used as an accelerator to decompose peroxide into free radicals
b. Free radicals initiate polymerization of MMA into PMMA
c. New PMMA is formed as a matrix around residual PMMA powder particles
d. Linear shrinkage is 5% to 7% of monomer on polymerization
3. Manipulation
a. P/L mixed to form dough or fluid resin to fill mold
b. Mold heated to start and control reaction
Celecoxib
Pharmacology
Celecoxib
is a highly selective COX-2 inhibitor and primarily inhibits this isoform of cyclooxygenase, whereas traditional NSAIDs inhibit both COX-1 and COX-2. Celecoxib is approximately 10-20 times more selective for COX-2 inhibition over COX-1.
Being a sulphonamide can cause skin rash & hypersensitivity rxn., occasional oedema& HT.
Indication
Osteoarthritis ( 100‐200mg BID ) , rheumatoid arthritis, dysmenorrhea, acute gouty attacks, acute musculoskeletal pain.
Microbes causing Food poisoning
Microbiology
Infectious
Salmonella [poultry, meat, eggs]
Salmonella enteritidis
Vibrio parahaemolyticus [seafood]
Enterohemorrhagic E. coli
Other diarrhetic E. coli
Clostridium perfringens [reheated meat]
Yersinia enterocolitica
Campylobacter jejuni/coli
Cholera vibrio [seafood]
Shigella
Typhus bacilli, paratyphoid bacilli
Vibrio vulnificus [seafood]
Toxic
Staphylococcus aureus [meats, mayo, custard]
Clostridium botulinum [canned foods]
Bacillus cereus [reheated rice]
Viral food poisoning
Norovirus
Sapovirus
Viral hepatitis A
Viral hepatitis E
Protozoa
Cryptosporidium
Cyclospora
Branches of Anatomy
Anatomy
Gross anatomy-study of structures that can be identified with the naked eye; usually involves the use of cadavers
Microscopic anatomy (histology)-study of cells that compose tissues and organs; involves the use of a microscope to study the details of the species
Developmental anatomy (embryology)-study of an individual from beginning as a single cell to birth
Comparative anatomy -comparative study of the animal structure in regard to similar organs or regions
Dautrey Procedure
General SurgeryDautrey Procedure
The Dautrey procedure is a surgical intervention aimed at
preventing dislocation of the temporomandibular joint (TMJ) by creating a
mechanical obstacle that restricts abnormal forward translation of the condylar
head. This technique is particularly beneficial for patients who experience
recurrent TMJ dislocations or subluxations, especially when conservative
management strategies have proven ineffective.
Indications:
The Dautrey procedure is indicated for patients with a history of
recurrent TMJ dislocations. It is particularly useful when conservative
treatments, such as physical therapy or splint therapy, have failed to
provide adequate stabilization of the joint.
Surgical Technique:
Osteotomy of the Zygomatic Arch: The procedure
begins with an osteotomy, which involves surgically cutting the
zygomatic arch, the bony structure that forms the prominence of the
cheek.
Depressing the Zygomatic Arch: After the osteotomy,
the zygomatic arch is depressed in front of the condylar head. This
depression creates a physical barrier that acts as an obstacle to the
forward movement of the condylar head during jaw opening or excessive
movement.
Stabilization: The newly positioned zygomatic arch
limits the range of motion of the condylar head, thereby reducing the
risk of dislocation during functional activities such as chewing or
speaking.
Mechanism of Action:
By altering the position of the zygomatic arch, the Dautrey
procedure effectively changes the biomechanics of the TMJ. The new
position of the zygomatic arch prevents the condylar head from
translating too far forward, which is a common cause of dislocation.
Postoperative Care:
Following the procedure, patients may require a period of recovery
and rehabilitation. This may include:
Dietary Modifications: Soft diet to minimize
stress on the TMJ during the healing process.
Pain Management: Use of analgesics to manage
postoperative discomfort.
Physical Therapy: Exercises to restore normal
function and range of motion in the jaw.
Outcomes:
The Dautrey procedure has been shown to be effective in preventing
recurrent TMJ dislocations. Patients often experience improved joint
stability and a better quality of life following the surgery. Successful
outcomes can lead to reduced pain, improved jaw function, and enhanced
overall satisfaction with treatment.
Ketamine
Pharmacology
Ketamine
- Causes a dissociative anesthesia.
- Is similar to but less potent than phencyclidine.
- Induces amnesia, analgesia, catalepsy and anesthesia, but does not induce convulsions.
- The principal disadvantage of ketamine is its adverse psychic effects during emergence from anesthesia. These include: hallucinations, changes in mood and body image.
- During anesthesia, many of the protective reflexes are maintained, such as laryngeal, pharyngeal, eyelid and corneal reflexes.
- Muscle relaxation is poor.
- It is not indicated for intracranial operations because it increases cerebrospinal fluid pressure.
- Respiration is well maintained.
- Arterial blood pressure, cardiac output, and heart rate are all elevated.