Multiple Choice Question Test - X (Basic Periodontology).
Leukocytes, especially neutrophils, are key players in the battle against bacteria in the sulcular region. The rate at which neutrophils migrate through the gingival sulcus into the oral cavity [i.e. the orogranulocytic migratory rate (OMR)] is increased in the presence of gingival inï¬‚ammation.
Reference: Uitto J-V. (2003). "Gingival crevice fluid - an introduction." Periodontol 2000 31: 9-11.
During this stage of gingival inflammation, the transition from gingivitis to periodontitis is initiated. The connective tissue fibers below the junctional epithelium are destroyed; the epithelium migrates along the root surface. Plasma cells contribute to >50% of the cell types. Advanced lesion has all the characteristics of established lesion except that alveolar bone loss occurs, fiber damage is extensive and the junctional epithelium migrates apically from cementoenamel junction.
Reference: Periodontology at a Glance. Chapter 8, page 17.
BMP-1 Genes for BMP 1 are located on chromosome 8. It does not belong to the TGF-β family of proteins. It is a metalloprotease that acts on procollagen I, II, and III. It is involved in cartilage development.
BMP-2 It is a major inducer of osteoblast differentiation. The genes are located on chromosome 20.
BMP-3 Induces bone formation. The genes are located on chromosome 14.
BMP-4 Regulates the formation of teeth, limbs and bone formation. It also plays a role in fracture repair. Genes are located on chromosome 14.
BMP-5 Performs functions in cartilage development. Genes are located on chromosome 6.
BMP-6 Plays a role in joint integrity in adults. Genes are located on chromosome 6.
BMP-7 Plays a key role in osteoblast differentiation. It also induces the production of SMAD1. Also key in renal development and repair. Genes are located on chromosome 20. It is also known as osteogenic protein-1.
Bacteriocin produced by A. actinomycetemcomitans is active against Streptococcus sanguis strains, Streptococcus uberis, and Actinomyces viscosus as well as other strains of A. actinomycetemcomitans, but not against other crevicular bacteria, including other streptococci and actinomycetes.
Reference: B F Hammond, S E Lillard, and R H Stevens. A bacteriocin of Actinobacillus actinomycetemcomitans. Infect Immun. 1987 March; 55(3): 686–691.
Deficiency of complement regulators CD59 and DAF leads to a disease called paroxysmal nocturnal haemoglobinuria (PNH). PNH is a rare haemolytic disorder characterized by intravascular haemolysis, haemoglobinuria and a tendency to vascular thrombosis. The frequency of PNH is approximately 1–10 per one million. The course of PNH varies, the median survival time from diagnosis is 10–15 years but spontaneous recoveries are known to occur.
Reference: Seppo Meri et al. Complement Regulatory Proteins. Encyclopedia Of Life Sciences.
In mammals, the early stages of B cell maturation occur in the fetal liver and bone marrow. B cell development begins in the fetal liver and continues in the bone marrow throughout life. The stages in B cell development in the bone marrow are:
Stem cell > pro-B cell > pre-B cell > small pre-B cell > immature B cell > mature B cell.
CRPs are produced by the liver in response to inflammatory cytokines. Plasma CRP is produced only by hepatocytes, predominantly under transcriptional control by the cytokine IL-6, although other sites of local CRP synthesis and possibly secretion have been suggested. Interleukin-6 (IL6), produced predominantly by macrophages and adipocytes, induces rapid release of CRP. CRP rises up to 50,000 fold in acute inflammation, such as severe acute infection or trauma.
Reference: Mark B. Pepys and Gideon M. Hirschfield. C-reactive protein: a critical update. J Clin Invest. 2003;111(12):1805–1812.
F nucleatum has the potential to be periodontal pathogen because of its number and frequency in periodontal lesions, its production of tissue irritants, its synergism with other bacteria in mixed infections, and its ability to form aggregates with other suspected pathogens in periodontal disease and thus act as a bridge between early and late colonizers on the tooth surface.
Reference: A I Bolstad, H B Jensen and V Bakken. Taxonomy, biology, and periodontal aspects of Fusobacterium nucleatum. Clin. Microbiol. Rev. 1996, 9(1):55.
The metabolism of the microorganisms produces gradients within the biofilm; for example, in nutrients and fermentation products, and in pH and redox potential (Eh). Bacteria respond to these fluctuating changes in environmental conditionsmby altering their patterns of gene expression.
Reference: Philip D. Marsh, Annette Moter & Deirdre A. Devine Dental plaque biofilms: communities, conflict and control. Periodontology 2000, Vol. 55, 2011, 16–35.
osteoclasts are multinucleated cells, responsible for bone resorption. They are also characterised by the presence of an actin, vinculin and talin containing clear (sealing) zone in the peripheral cytoplasm of cell that delineates a more central region of membrane infoldings (plates) and finger-like processes termed the ruffled border. Resorption of bone occurs in an acidified extracellular matrix compartment as a result of the combined actions of a variety of ruffled border membrane-associated enzymes including a tartrate-resistant, vanadate-sensitive acid adenosine triphosphatase, carbonic anhydrase isozyme II and proton-pumping adenosine triphosphatases.
Reference: Jaro Sodek & Marc D.Mckee.Molecular and cellular biology of alveolar bone. Periodontology 2000, Vol. 24, 2000, 99–126.