Post-transcriptional modification of RNA | Crack AIPGDEE

Which of the following is not a post-transcriptional modification of RNA?
A.   Splicing                              
B. 5'- capping
C.   3'-poly adenylation            
D. Glycosylation

    Glycosylation has not been mentioned as a post-transistional modification of RNA. 5' - capping: Is required both for efficient translation initiation and protection of 5' - end of MRNA from attack by 5'-3' exonucleases. 3' - poly adenylatlon: Added to 3'-end of mRNA molecules in a post transcriptional processing step. This appears to protect the 3'-end of mRNA from 3' - 5' exo-nuclease attack. Splicing (Removal of introns): Introns or intervening sequences that do not code for proteins are removed. This splicing occurs in the nucleus and serves to bring the exons together. After removal of introns the mature mRNA molecules leave the nucleus.

“Syncope” occurrence | AIPGDEE Guide

“Syncope” occurs while operative processes due to:
A. Cerebral edema  
B. Cerebral hyperemia
C. Cerebral hypoxia              
D. Cerebral degeneration

.  Ans. (C) Cerebral hypoxia: 

- Cerebral syncope is caused by a sudden drop in cardiac output and cerebral perfusion due to an arrhythmia or a mechanial problem.

- Inappropriate Vasodilatation also causes symptoms by reducing cerebral perfusion”- 

- Syncope or fainting is perhaps the most frequently complication associated with local anesthesia in the dental office.

- This is a form of neurogenic shock and is cause by cerebral ischemia secondary to vasodilatation or an increase in the peripheral vascular bed, with a corresponding drop in blood pressure

The non-cariogenic substitute used to replace the cariogenic diet

The non-cariogenic substitute used to replace the cariogenic diet is
A. Lactose                      
B. Glucose
C. Cooked Starch      
D. Sorbito

Ans. (D) Sorbitol: “The alcohol derivatives have been added as substitute for cariogenic diet”

Sugars present in the human diet is considered the most caries promoting

Which of the following sugars present in the human diet is considered the most caries promoting?
A.   Sucrose
B.   Fructose
C.   Lactose                    
D.   Glucose

       Ans. (A) Sucrose:
• The patient diet and dental caries activity are related. From the dietetic view point, dental caries widely accepted as being caused by the ingestion of fermentable carbohydrates, particularly sucrose.

• Fermentable carbohydrates and more specifically sucrose are rarely eaten as such. They are eaten as components of foods that contain other ingredients and have different textures.

• The cariogenic potential of foods containing sucrose, have the ability to

- Be retained by teeth        - Form acids          - Dissolve enamel         - Neutralize or buffer acids.

Primordial prevention | AIPGDEE Guidance

       Primordial prevention is used to:

     A. Prevent development of risk factor in the community.

     B. Prevent the transmission of diseases.

     C. Prevent the development of diseases.

     D. To establish the diagnosis and treatment of disease.

        Ans. (A) - Prevent development of risk factor in the community 

• Primordial Prevention a new concept is receiving special attention in the prevention of chronic diseases. *

• This primary prevention in its purest sense, that is prevention of the emergence or development of risk factor in countries or population groups in which they have not appeared.

• For example, many adult health problems (e.g. obesity, hypertension) have their early origins in childhood, because this is the time when lifestyles are formed (for example, smoking, eating patterns, physical exercise)

• In primordial prevention, efforts are directed towards discouraging children from adopting harmful lifestyles. The main intervention in primordial prevention is through individual and mass education.

X-Rays a brief

X-Rays

X Rays have a partiular wavelength and energy value.
the ability of the radiation to penetrate material and being absorbed is dependent on material type and energy of the radiation.

Half value layer (HVL) - level of radiation at which radiation intensity becomes one half of that at the surface. which is dependent on voltage and filteration.

Xrays and / or gamma rays which have higher kilovoltage have shorter wavelength and higher penetrating powers..

Tachycardia and Hypoxia | PGI MCQs for MD MS Preparations

Tachycardia is caused by hypoxia due to:
A. Reflexely through peripheral chemoreceptors                
B. Diffuse vasodilatation
C. Through central chemoreceptor                                          
D. Secondarily after by hyperventilation

Ans. B 

·         In hypoxia, with the reticulum of PO2 cerebral blood flow increases (due to vasodilation) to maintain O2 delivery in the brain.

Effects of Hypoxia

·         Cerebral blood flow:

·         Increases if PaO2 decreases.

·         If ↓ PaO2 is associated with hyperventilation: cerebral blood flow falls & hypoxia intensified.

·         Synaptic discharge: Increases by directly stimulating the vasomotor center.

·         Lactic acidosis: In hypoxia a large proportion of pyruvate is reduced to lactic acid. (Glucose is broken down to pyruvate under condition & generates ATP)

Most common microorganism of oral flora | AIIMS MDS Preparations

Most common microorganism of oral flora are 

a) Aerobic streptococci b) Anaerobic streptococci 

c) Facultative streptococci d) B-hemolytic streptococci

Ans C. 

Facultative streptococci form the most numerous single group in the oral cavity

Averaging in most surveys nearly V2 the viable counts of saliva and dorsum of tungue and about J/4th of viable counts of plaque and gingival sulcus.

>- The pyogenic (hemolytic) varieties are usually scarce in the oral cavity this has been attributed to a salivary inhibitory factor distinct from lysozyme or hydrogen peroxide. The pyogenic streptococci isolated occasionally from the oral cavity probably derived frcnn the oronnsopharynx and should not be regarded as resident flora. By far the most abundant of oral streptococci are those considered in viridans gp. These were divided in two broad groups

i) Strept. salivarius

ii) Strept. mitis

Strept. salivarius - average about half the viable count of facultative streptococci from saliva or tungue scrapings.

This organism ordinarily numbers less than 1 % of viable count in plaque.

> Majority of other oral facultative streptococci are strep. mitis, mutans and sanguis.

> S.sanguis - makes up about V2 of the count of facultative streptococci in plaque, which seems to be their primary habitat - causes SABE

	Gingival crevice area	Dental plaque	tongue	saliva
Gram positive anaerobic cocci Streptococci s.salivarious Enterococci staphylococci	28.8 27.1 N.D 7.2 1.7	28.2 27.9 N.D    - 0.3	44.8 38.3 8.2 N.D 6.5	46.8 41.0 4.6 1.3 4.0
Gram(+)Anaerofcocci	7.4	12.6	4.2	13.0
Gram(-)fac.cocci	0.4	0.4	3.4	1.2
Gram(-)amaer cocci	10.7	6.4	16	15.9

So from the above references it is shown that facultative streptococci is the most common microorganism of oral  cavity.

Cohort Group | Crack AIPGDEE

A group which is being studied during a study is called as ? 
A. Pannel Group
B. Cohort Group
C. Controls
D. None

Ans. (B) 

Cohorts are groups of persons defined in terms of characteristic manifest prior to the appearance of disease manifestation. The cohorts thus defined are followed up over time to determine the frequency of disease developing in them. 

Cluster headache | AIPGMEE Preparations

Which of the following is not found in cluster headache
a) occurs mainly in young man >50 years
b) site is unilateral in orbital region
c) intermittent episodes of pain of between 15 to 180 minutes duration on daily basis for several weeks interspersed with pain free periods of months
d) aura phase is common

Ans d

Sex. More common in males than females.

Age. Predominantly affects individuals under the age of 50 years.

Nature. An intense aching pain that disturbs sleep; attacks may occur at the same time each day.

Duration. Typically, there are intermittent pain of between 15 and 180 minutes' duration on a basis for several weeks, interspersed with pain-free periods months rather than days in duration.

Site. The pain is localised to one side of the face, typically affecting the cheek, orbit, forehead and temple.

Nerve Responsible for Sneezing | Crack AIPGDEE 2016

Tickling sensation felt in nose by or sneezing is carried in which nerve

a) Facial nerve

b) Glossopharyngeal nerve

c) Nasopalatine nerve

d) Nasociliary nerve

Ans(d) 

Sneezing reflex is triggered by a variety of stimuli, the most common of which is Stimulation of nasal mucosa (trigcminul nerve endings) by mechanical or chemical stimuli. 

Sneezing reflex has 2 phases

a) Nasal 

•The afferent limb of the nasal phase consists of the ethmoidal and olfactory (cranial

nerve T) which projects to sneezing centre in medulla oblongata.

•So from above reference it is clear that tactile sensation before sneezing is due to ethmoidal nerve. which is  the branch of nasociliary nerve.

•So answer is nasociliary nerve i.c, option d.

•The efferent limb of nasal phase consists of preganglionic fibres of greater petrosal nerve (cranial nerve VlI ) and

the sphenopalatine ganglia (cranial nerve VII) which innervates glands and blood vessels in the nose.

b) Respiratory

•Respiratory phase of the sneezing reflex commences when a critical number of inspiratory and expiratory neurons

arc recruited by sneezing centre.

Another reference - sternutogenesis

A sneeze involves dozens of muscles in the face, chest and abdomen, all operuuug in a correct sequence that has been hard wired in the brain and spinal cord. The sequence is mediated by trigerninal nerve particularly the anterior ethmoidal, posterior nasal and infraorbital brunches. 

Cell in Cerebral Cortex MCQ | AIPGMEE, AIIMS Preparations

Which cells are not present in cerebral cortex

a) Purkinjc       b) Stellate         c) Cajal      d) Pyramidal 

Ans (a)1 Purkinje are present in cerebellum and other three arc present in cerebral cortex. (cerebrum)

Ref. Purkinje cells (wikipedia)

Purkinjc cells - are a class of GABAergic neurons located in the cerebellar cortex. These are a special type of nerve

cell that carries each and every piece of information outputted by the cerebellum. The cells passes a great deal of

control over the refinement of motor activities.

Cajal cells = Cajal cells of cerebral cortex am special cells or horizontal cells located in the I" layer (molecular layer I) in the cortex. Cajal retzius cells establish early neuronal circuitry in the developing brain and express a number of genes known to be important in human cerebral development.

Stellate cells:  Star shaped cells in the 2'''' and 4'" layer of the cortex and large stellate cells in the deeper part of 3'" layer in the visual cortex.

Pyramidal cells =  A pyramidal cells (or pyramidal neuron, or projection neuron) is a multipolar neuron located in the hippo campus and cerebral cortex. Pyramidal neurons compose 800/0 of neurons in cortex and release glutamate as their neurotransmitter.

making them the major excitatory component of the cortex.

Chorda Tympani | Crack AIPGDEE Guidance

Chorda tympani, true is 
a) Carries P-sympathetic fibres to submandibular gland
b) Part of nerve of pterygoid canal
c) Sensory to tympanic membrane
D} Joins auriculotemporal nerve

Ans. (a) 

Regarding option b) Deep petrosal nerve is a branch of carotid plex LIS round internu I curotid artery. It joins the greater petrosal nerve to form nerve of pterygoid canal.

Regarding option c) Nerve supply of tympanic membrane 

Outer surface; the unrcroi nferior pan is supplied by auriculo temporal nerve and tile posterosuperior part by the auricular branch of vagus nerve.

Inner surface: this is supplied by the tympanic branch of the glossopharyngeal nerve through the tympanic plexus.

Option d) It joins the lingual nerve. not to auriculotemporal nerve.

Now regarding optiun a) 

Chorda tympani carries (a) preganglionic secretomotor fibres to the submandibular ganglion for supply of' submandibular and Sublingual salivary glands; and taste fibres from the anterior 213"" of tongue.

Submandibular ganglion = this is a parasympathetic peripheral ganglion. It is a relay station for secretomotor fibres to the submandibular and sublingual salivary glands.

Cardiac conditions prophylaxis for endocarditis is NOT recommended in patients

For what cardiac conditions prophylaxis for endocarditis is NOT recommended in patients receiving dental care? 
a. Prosthetic cardiac valves          
b. Previous bacterial endocarditis
c. Previous coronary artery bypass graft surgery        
d. Surgically constructed systemic pulmonary shunts or conduits.

The correct answer is C: Cardiac conditions that do not require endocarditis prophylaxis

• Isolated secundum atrial septal defect

• Surgical repair of atrial septal defect, ventricular septal defect, or patent ductus arteriosus (without residua beyond 6 months)

• Previous coronary artery bypass graft surgery

• Mitral valve prolapse without valvular regurgitation

• Physiologic, functional, or innocent heart murmurs

• Previous Kawasaki disease without valvular regurgitation

Radioresistant tumor | MDS coaching & Preparations B-IDS 09818001730, 08690014009

Whlch of the following is most Radioresistant tumor?
A. Ewing's Sarcoma
B. Ameloblastoma
C. Carcinoma maxillary sinus
D. Carcinoma alveolus

Ans, (B)

Frissell reviewed the reported cases in which radiation therapy was utilized and found that there was considerable variance of opinion as to its benefit. The report of Kimm, supported by study of serial biopsy on the treatment of the ameloblastoma by radiation indicated that this neoplasm is highly radioresistant and that the use of this form of therapy is not warranted.