MDS PREP
The presence of pulp stones on the radiograph of a tooth indicates the presence of
1) Acute pulpitis
2) Acute pulpalgia
3) Chronic periodontitis
4) None of the above
Oral Pathology
Answer: 4
After mixed dentition stage, the arch length from first molar to first molar usually
1) Remains same
2) Increase
3) Decrease
4) Doubles
Orthodontics
Answer: 3
What is the name of the live oral vaccine for typhoid fever and what is its mechanism of action?
1) Typhoral, a Gal E mutant of S. typhi that "self-destructs" after a few cell divisions
2) CholeraVax, a killed whole-cell vaccine
3) Salmonellosis vaccine, a live attenuated strain of S. paratyphi
4) Shigellosis vaccine, a bacteriophage preparation
General Microbiology Answer: 1the live oral vaccine for typhoid fever is Typhoralx, which is a Gal E mutant of S. typhi. The mechanism of action involves the attenuated bacteria colonizing the intestinal mucosa and inducing an immune response that protects against subsequent infection with the pathogenic strain.
A 10-year-old child presents with anaemia and recurrent fractures. The X-ray shows diffuse hyperdensity of bone. The diagnosis is most likely to be
1. Osteogenesis imperfecta
2. Osteopetrosis
3. Osteochondroma
4. Hyperparathyroidism
The diagnosis for a child with anemia and recurrent fractures showing diffuse hyperdensity of bone is osteopetrosis.
Biopsy specimens removed for examinations are immediately placed in
1) 10 % ethanol
2) 10 % formalin
3) Hydrogen peroxide
4) 1 % formalin
Oral Surgery
Answer: 2
Formalin, specifically 10% neutral buffered formalin, is the standard fixative used for preserving biopsy specimens. It helps to maintain the tissue architecture and cellular details, making it suitable for histopathological examination. Ethanol is not typically used for routine tissue fixation as it can cause tissue shrinkage and distortion. Hydrogen peroxide is not a fixative and is used for different purposes, such as disinfection. A 1% formalin solution is too dilute for effective fixation.
What is the primary function of protein S?
1) Inhibition of factor Xa
2) Inhibition of factor VIIIa
3) Inhibition of factor IIa (thrombin)
4) Activation of factor V
Protein S, in complex with activated protein C, acts as a cofactor for the inhibition of factor Xa, thus playing a role in the regulation of the coagulation cascade and preventing thrombus formation.