NEET MDS Synopsis
Amphotericin B
Pharmacology
Amphotericin B
Main use is in systemic fungal infections (e.g. in immunocompromised patients), and in visceral leishmaniasis. Aspergillosis, cryptococcus infections (e.g. meningitis) and candidiasis are treated with amphotericin B. It is also used empirically in febrile immunocompromised patients who do not respond to broad-spectrum antibiotics.
MOA:
As with other polyene antifungals, amphotericin B associates with ergosterol, a membrane chemical of fungi, forming a pore that leads to K+ leakage and fungal cell death
Side effects: nephrotoxicity (kidney damage) , headache, vomiting, convulsions and fever
The side-effects are much milder when amphotericin B is delivered in liposomes
Orthodontic MCQ 1
Orthodontics
1. An adult patient with a Class II molar relationship and a cephalometric ANB angle of 2 degrees has which type of malocclusion?
1. Class II dental malocclusion
2. Class II skeletal malocclusion
3. Class I dental malocclusion
4. Class II skeletal malocclusion
ans 1. The molars are Class II but the skeletal relationship described by a normal ANB measurement is normal, so the malocclusion is dental
in origin.
2. Which of the following reactions is least likely to be observed during orthodontic treatment?
1. Root resorption
2. Devitalization of teeth that are moved
3. Mobility of teeth that are moved
4. Development of occlusal interferences
Ans 2. Root resorption is common during orthodontic treatment, although lesions often repair on the root surface. Mobility of teeth is also common as the PDL reorganizes and widens during tooth movement. It is uncommon for teeth to become devitalized as a result of orthodontic movement unless they have also been substantially compromised by injury or infection.
3. A 7-year-old has a 4-mm maxillary midline diastema. Which of the following should be done?
1. Brackets should be placed to close it.
2. A radiograph should be taken to rule out the presence of a supernumerary tooth.
3. Nothing should be done. It will close on its own.
4. Nothing should be done. Treatment should be deferred until the rest of the permanent dentition erupts.
Ans. 2. When a large diastema greater than 2 mm is present, it will probably not close on its own. Diagnostic tests, such as a radiograph, should be accomplished to rule out the presence of a supernumerary tooth, usually a mesiodens.
4. When Class III elastics are used, the maxillary first molars will _____.
1. Move distally and intrude
2. Move mesially and extrude
3. Move mesially and intrude
4. Move only mesially; there will be no movement in the vertical direction
ans 2. Class III elastics are worn from the maxillary first molars to the mandibular canines. The force system created by Class III elastics will produce mesial movement and extrusion of the maxillary first molars.
5. Ideally, Orthodontic traction to pull an impacted tooth to line of arch should begin
1. at 2-3 months post surgically
2. As soon as possible after surgery
3. After a waiting period of at least1.5 months
4. Only the method of traction is critical, not the time
ans 2
Mechanical approaches for aligning unerupted teeth. Orthodontic traction to pull an unerupted tooth toward the line of the arch
should begin as soon as possible after surgery Ideally a fixed orthodontic appliance should already be in place before the unerupted tooth is exposed, so that orthodontic force can be applied immediately. If this is not practical, active orthodontic
movement should being no later than 2 or 3 weeks post-surgically.
Rocky Mountain Spotted Fever
General Pathology
Rocky Mountain Spotted Fever (Spotted Fever; Tick Fever; Tick Typhus)
An acute febrile disease caused by Rickettsia rickettsii and transmitted by ixodid ticks, producing high fever, cough, and rash.
Symptoms and Signs
The incubation period averages 7 days but varies from 3 to 12 days; the shorter the incubation period, the more severe the infection. Onset is abrupt, with severe headache, chills, prostration, and muscular pains. Fever reaches 39.5 or 40° C (103 or 104° F) within several days and remains high (for 15 to 20 days in severe cases),
Between the 1st and 6th day of fever, most patients develop a rash on the wrists, ankles, palms, soles, and forearms that rapidly extends to the neck, face, axilla, buttocks, and trunk. Often, a warm water or alcohol compress brings out the rash. Initially macular and pink, it becomes maculopapular and darker. In about 4 days, the lesions become petechial and may coalesce to form large hemorrhagic areas that later ulcerate
Neurologic symptoms include headache, restlessness, insomnia, delirium, and coma, all indicative of encephalitis. Hypotension develops in severe cases. Hepatomegaly may be present, but jaundice is infrequent. Localized pneumonitis may occur. Untreated patients may develop pneumonia, tissue necrosis, and circulatory failure, with such sequelae as brain and heart damage. Cardiac arrest with sudden death occasionally occurs in fulminant cases.
Different Systems of the CNS & their functions
Pharmacology
Different Systems of the CNS & their functions
These systems are pathways formed of specific parts of the brain and the neurons connecting them.
They include:
1.The pyramidal system
2.The extrapyramidal system
3.The limbic system
4.The reticular formation
5.The tuberohypophyseal system
The pyramidal system:
It originates from the motor area of the cerebral cortex and passes through the spinal cord, therefore it is also known as the “corticospinaltract”.
It is responsible for the regulation of the fine voluntary movements.
The extrapyramidal system:
It also controls the motor functionbut involves areas other than the corticospinal tract.
It is involved in the regulation of gross voluntary movements, thus it complements the function of the pyramidal system.
The “basal ganglia” constitute an essential part of this system.
Degenerative changes in the pathway running from the “substantianigra”to the “corpus striatum”(or nigrostriatal pathway) may cause tremors and muscle rigidity characteristic of “Parkinson’s disease”.
The limbic system:
The major parts of this system are: the hypothalamus, the basal ganglia, the hippocampus(responsible for short term memory), and some cortical areas.
The limbic system is involved in the control of “behavior”& “emotions”.
The reticular formation:
It is composed of interlacing fibers and nerve cells that run in all directions beginning from the upper part of the spinal cord and extending upwards.
It is important in the control of “consciousness” and “wakefulness”.
The tuberohypophyseal system:
It is a group of short neurons running from the hypothalamusto the hypophysis(pituitary gland) regulating its secretions.
COMPOSITE RESINS - Finishing and Polishing
Dental Materials
Finishing and Polishing
Remove oxygen-inhibited layer .Use stones or carbide burs for gross reduction.Use highly fluted carbide burs or special diamonds for fine reduction.Use aluminum oxide strips or disks for finishing. Use fine aluminum oxide finishing pastes. Microfills develop smoothest finish because of small size of filler particles
Phenytoin
Pharmacology
Phenytoin (Dilantin): for tonic-clonic and all partial seizures (not effective against absence seizures)
Mechanism: ↓ reactivation of Na channels (↑ refractory period, blocks high frequency cell firing, ↓ spread of seizure activity from focus)
Side effects: ataxia, vertigo, hirsutism (abnormal hair growth), gingival hyperplasia, osteomalacia (altered vitamin D metabolism and ↓ Ca absorption), blood dyscrasias (rare; megaloblastic anemia, etc)
Drug interactions: induces hepatic microsomal enzymes (can ↓ effectiveness of other drugs); binds tightly to plasma proteins and can displace other drugs
Nucleic Acids
PhysiologyNucleic Acids:
Two major types: DNA
RNA (including mRNA, tRNA, & rRNA)
Both types have code which specifies the sequence of amino acids in proteins
DNA = archival copy of genetic code, kept in nucleus, protected
RNA = working copy of code, used to translate a specific gene into a protein, goes into cytoplasm & to ribosomes, rapidly broken down
Nucleic acids are made of 5 nucleotide bases, sugars and phosphate groups
The bases make up the genetic code ; the phosphate and sugar make up the backbone
RNA is a molecule with a single strand
DNA is a double strand (a double helix) held together by hydrogen bonds between the bases
A = T; C= G because:
A must always hydrogen bond to T
C must always hydrogen bond to G
Most Common Site of Primary Bone Tumors
Orthopaedics
Most Common Site of Primary Bone Tumors
Epiphyseal
- Chondroblastoma (before physeal closure)
- Osteoclastom/Giant cell tumor (after physeal closure in adults)
- Articular osteochondroma
Metaphyseal
- Chondrosarcoma
- Enchondroma
- Osteochondroma
- Osteoblastoma
- Bone cyst
- Osteosarcorna
- Osteoclastoma (in children)
- Osteomyelitis mostly starts in metaphysis
?Diaphyseal
- Round cell lesions: Ewing’s sarcoma/Multiple myeloma /Reticulum cell sarcoma
- Admantinoma
- Osteoid osteoma