contains descriptive and other studies on genetics and epigenetics and whole gene concepts from central dogma to future concepts . Dr Harshavardhan Patwal
”Contemporary Biomarkers In Periodontitis”- Guest lecture as a part of Dr NTRUHS Zonal CDE programme at Government Dental College and Hospital, Hyderabad, India on 281/1/2011, SIBAR Institute of Dental Sciences, Guntur, India on 29/12/12 and at Meghna Institute of Dental Sciences, Nizamabad, India on 31/7/2013.
The future of dentistry and periodontics lies in regeneration. The goals of periodontal therapy lies in not only the arrest of periodontal disease progression but also regeneration of the lost periodontal structures. This presentation provides a review of the current understanding of the regeneration of the periodontium and the procedures involved to restore the periodontal tissues around the teeth.
Role of genetics in periodontal diseasesAnushri Gupta
Terminologies in Genetics
Genetic study design
genetic syndrome and disease associated with periodontal diseases, heretibility of periodontal disease, gene library, gene therapy
”Contemporary Biomarkers In Periodontitis”- Guest lecture as a part of Dr NTRUHS Zonal CDE programme at Government Dental College and Hospital, Hyderabad, India on 281/1/2011, SIBAR Institute of Dental Sciences, Guntur, India on 29/12/12 and at Meghna Institute of Dental Sciences, Nizamabad, India on 31/7/2013.
The future of dentistry and periodontics lies in regeneration. The goals of periodontal therapy lies in not only the arrest of periodontal disease progression but also regeneration of the lost periodontal structures. This presentation provides a review of the current understanding of the regeneration of the periodontium and the procedures involved to restore the periodontal tissues around the teeth.
Role of genetics in periodontal diseasesAnushri Gupta
Terminologies in Genetics
Genetic study design
genetic syndrome and disease associated with periodontal diseases, heretibility of periodontal disease, gene library, gene therapy
Genetic factors in pathogen colonisation is emerging as a new field of research as " infectogenomics". The susceptible host to periodontal disease directs towards genetic factors playing a role in periodontal disease pathogenesis. Earlier identification of gene polymorphisms associated with periodontal disease preogression may help in early diagnosis, treatment of such susceptible host.
Bone Morphogenetic Proteins - Role in Periodontal RegenerationDr.Shraddha Kode
BMP's are the multifunctional growth factors extensively studied throughout the years. It has recently gained a lot of interest as therapeutic agents in periodontal regeneration.
Definition of periodontal pocket, classification, Histopathology of periodontal pocket, microflora involved, pathogenesis, periodontal pocket as a healing lesion, microtopography of root surface, treatment of periodontal pocket
Inflammation and Immunity in periodontitis pptPerio Files
Local destruction of periodontium occurs mostly by activation of immune and inflammatory response, initiated by plaque. First innate immune response is activated followed by specific immune response.
Useful for BDS and MDS students
Pathogenesis is derived from the Greek work ‘pathos’ meaning suffering and ‘ genesis’ meaning generation or creation. Plaque is considered as the main etiologic factor in the pathogenesis of periodontal disease.
As a periodontist, it is of utmost importance to understand the genetic basis of inheritance in periodontal diseases be able to relate to the various polymorphisms associated with periodontal diseases. This ppt presents the basics of genetics from the point of view of future understanding of polymorphisms related to periodontal diseases.
Genetic factors in pathogen colonisation is emerging as a new field of research as " infectogenomics". The susceptible host to periodontal disease directs towards genetic factors playing a role in periodontal disease pathogenesis. Earlier identification of gene polymorphisms associated with periodontal disease preogression may help in early diagnosis, treatment of such susceptible host.
Bone Morphogenetic Proteins - Role in Periodontal RegenerationDr.Shraddha Kode
BMP's are the multifunctional growth factors extensively studied throughout the years. It has recently gained a lot of interest as therapeutic agents in periodontal regeneration.
Definition of periodontal pocket, classification, Histopathology of periodontal pocket, microflora involved, pathogenesis, periodontal pocket as a healing lesion, microtopography of root surface, treatment of periodontal pocket
Inflammation and Immunity in periodontitis pptPerio Files
Local destruction of periodontium occurs mostly by activation of immune and inflammatory response, initiated by plaque. First innate immune response is activated followed by specific immune response.
Useful for BDS and MDS students
Pathogenesis is derived from the Greek work ‘pathos’ meaning suffering and ‘ genesis’ meaning generation or creation. Plaque is considered as the main etiologic factor in the pathogenesis of periodontal disease.
As a periodontist, it is of utmost importance to understand the genetic basis of inheritance in periodontal diseases be able to relate to the various polymorphisms associated with periodontal diseases. This ppt presents the basics of genetics from the point of view of future understanding of polymorphisms related to periodontal diseases.
Academic presentation on osseointegration of dental implants. A brief outline on surface modification, alveolar bone biology and phases of osseointegration
Periodontal disease susceptible group present advanced periodontal breakdown even though they achieve a high standard of oral hygiene. Various destructive enzymes and inflammatory mediators are involved in destruction. These are elevated in case of periodontal destruction. Host modulation aims at bringing these enzymes and mediators to normal level.
This ppt aims in highlighting the various host modulatory agents that can be put to use in periodontal therapy.
Concept of gene & ultra structure of geneJigar Patel
This presentation includes introduction of gene, gene concept, chemical composition and ultra structure of prokaryotic and eukaryotic gene for B.Sc students.
this is done by me and my team mates of Wayamba University Sri Lanka for our project.From now we decided to allow download this file.I would be greatful if you could send your comments..
And I'm willing to help you in similar works.I'm in final year of my degree(.BSc Biotechnology)..
pubudu_gokarella@yahoo.com
A complete set of chromosomes/genes inherited as a unit from one parent called genome. The entire genetic complement of a living organism.
The total amount of genetic information in the chromosomes of an organism, including its genes and DNA sequences. The genome of eukaryotes is made up of a single, haploid set of chromosomes that is contained in the nucleus of every cell and exists in two copies in the chromosomes of all cells except reproductive and red blood cells. The human genome is made up of about 35,000 genes.
Risk assessment is the determination of quantitative or qualitative estimate of risk related to a well-defined situation and a recognized threat (also called hazard). Quantitative risk assessment requires calculations of two components of risk (R): the magnitude of the potential loss (L), and the probability (p) that the loss will occur. An acceptable risk is a risk that is understood and tolerated usually because the cost or difficulty of implementing an effective countermeasure for the associated vulnerability exceeds the expectation of loss."Health risk assessment" includes variations, such as risk as the type and severity of response, with or without a probabilistic context.
Dental Implants have changed the face of dentistry over the last 25 years. What are dental implants? What is the history of dental implants? And how are they used to replace missing teeth? This section will give you an overview of the topic of dental implants, to be followed by more detail in additional sections.
As with most treatment procedures in dentistry today, dental implants not only involve scientific discovery, research and understanding, but also application in clinical practice. The practice of implant dentistry requires expertise in planning, surgery and tooth restoration; it is as much about art and experience as it is about science. This site will help provide you with the knowledge you need to make informed choices in consultation with your dental health professionals.
Dental Implants
Dental illustration by Dear Doctor
Let’s start from the beginning: A dental implant is actually a replacement for the root or roots of a tooth. Like tooth roots, dental implants are secured in the jawbone and are not visible once surgically placed. They are used to secure crowns (the parts of teeth seen in the mouth), bridgework or dentures by a variety of means. They are made of titanium, which is lightweight, strong and biocompatible, which means that it is not rejected by the body. Titanium and titanium alloys are the most widely used metals in both dental and other bone implants, such as orthopedic joint replacements. Dental implants have the highest success rate of any implanted surgical device.
Titanium’s special property of fusing to bone, called osseointegration (“osseo” – bone; “integration” – fusion or joining with), is the biological basis of dental implant success. That’s because when teeth are lost, the bone that supported those teeth is lost too. Placing dental implants stabilizes bone, preventing its loss. Along with replacing lost teeth, implants help maintain the jawbone’s shape and density. This means they also support the facial skeleton and, indirectly, the soft tissue structures — gum tissues, cheeks and lips. Dental implants help you eat, chew, smile, talk and look completely natural. This functionality imparts social, psychological and physical well-being.
There is no question that given the current state of the art in dentistry, that dental implants are pretty much the best way to replace teeth; they are stand alone tooth replacement systems that look and function just like natural teeth. They do not attach to adjacent teeth like a fixed bridge and don't have to be taken in and out like removable partial dentures.
A dental implant is a tooth root replacement made of titanium, which has the unique property of being osteophilic (osteo-bone, philic-loving) and actually fuses to bone. A crown, the part of the tooth that you see in your mouth, is attached to the implant. And the great thing about implants is they are not susceptible to decay or periodontal (gum) disease in the same way that teeth are.
Now here are a few important pointers, which hold for implants generally and are especially important in your case when replacing a front tooth for an imminent event . Dr Harshavardhan Patwal
Non surgical management of gingival recession- Dr Harshavardhan PatwalDr Harshavardhan Patwal
Treatment of gingival recession has become an important therapeutic issue due to the increasing number of cosmetic requests from patients. The dual goals of mucogingival treatment include complete root coverage, up to the cemento-enamel junction, and blending of tissue color between the treated area and non-treated adjacent tissues. Even though the connective tissue graft is commonly considered the “gold standard” for treatment of recession defects, it may not always be the best surgical option for every case. Dr Harshavardhan Patwal , Under non-experimental conditions, all root coverage procedures may be effective in terms of complete root coverage and excellent esthetics. Careful analyses of patient- and defect-related factors, however, are key considerations prior to selecting an appropriate surgical technique.
Occlusion, in a dental context, means simply the contact between teeth. More technically, it is the relationship between the maxillary (upper) and mandibular (lower) teeth when they approach each other, as occurs during chewing or at rest.
Malocclusion is the misalignment of teeth and jaws, or more simply, a "bad bite". Malocclusion can cause a number of health and dental problems.
Static occlusion refers to contact between teeth when the jaw is closed and stationary, while dynamic occlusion refers to occlusal contacts made when the jaw is moving. Dynamic occlusion is also termed as articulation. During chewing, there is no tooth contact between the teeth on the chewing side of the mouth.
Centric occlusion is the occlusion of opposing teeth when the mandible is in centric relation. Centric occlusion is the first tooth contact and may or may not coincide with maximum intercuspation. It is also referred to as a person's habitual bite, bite of convenience, or intercuspation position (ICP). Centric relation, not to be confused with centric occlusion, is a relationship between the maxilla and mandible. Dr Harshavardhan Patwal , Malocclusion is the result of the body trying to optimize its function in a dysfunctional environment. It can be associated with a number of problems, including crooked teeth, gum problems, the temporomandibular joint (TMJ), and jaw muscles. Teeth, fillings, and crowns may wear, break, or loosen, and teeth may be tender or ache. Receding gums can be exacerbated by a faulty bite. If the jaw is mispositioned, jaw muscles may have to work harder, which can lead to fatigue and or muscle spasms. This in turn can lead to headaches or migraines, eye or sinus pain, and pain in the neck, shoulder, or even back. Malocclusion can be a contributing factor to sleep disordered breathing which may include snoring, upper airway resistance syndrome, and / or sleep apnea (apnea means without breath). Untreated damaging malocclusion can lead to occlusal trauma.
Some of the treatments for different occlusal problems include protecting the teeth with dental splints (orthotics), tooth adjustments, replacement of teeth, medication (usually temporary), a diet of softer foods, TENS to relax tensed muscles, and relaxation therapy for stress-related clenching. Removable dental appliances may be used to alter the development of the jaws. Fixed appliances such as braces may be used to move the teeth in the jaws. Jaw surgery is also used to correct malocclusion.
Since the initial observations of oral bacteria within dental
plaque by van Leeuwenhoek using his primitive microscopes
in 1680, an event that is generally recognized as the
advent of oral microbiological investigation, oral microbiology
has gone through phases of “reductionism” and
“holism”. From the small beginnings of the Miller and
Black period, in which microbiologists followed Koch’s
postulates, took the reductionist approach to try to study
the complex oral microbial community by analyzing
individual species; to the modern era when oral researchers
embrace “holism” or “system thinking”, adopt new concepts
such as interspecies interaction, microbial community,
biofilms, poly-microbial diseases, oral microbiological knowledge
has burgeoned and our ability to identify the resident
organisms in dental plaque and decipher the interactions
between key components has rapidly increased, such
knowledge has greatly changed our view of the oral
microbial flora, provided invaluable insight into the
etiology of dental and periodontal diseases, opened the door
to new approaches and techniques for developing new
therapeutic and preventive tools for combating oral polymicrobial
diseases. Dr Harshavardhan Patwal
Like many other biological sciences, the study
of microbiology has gone through phases of
“reductionism” and “holism”. For a long time,
microbiologists took the reductionist approach to
study complex microbial communities by analyzing
individual bacterial species. The strategy was to
understand the whole by examining smaller components,
and has been the hallmark of much of the
industrial and scientific revolutions for the past
150 years. While reductionism has greatly advanced
microbiology, it was recognized that assembly of
smaller pieces cannot explain the whole! Modern
microbiologists are learning “system thinking” and
“holism.” From global gene regulation to “metagenomics”
to “biofilms”, microbiology is entering
an exciting new era with emphasis on revealing
and decoding the interactions of different elements
within a microbial community. The knowledge
obtained from “system thinking” is changing our
understanding of microbial physiology and our
ability to diagnose/treat microbial infections, and
will have great impact on oral microbiology as
well.
Oxidative stress reflects an imbalance between the systemic manifestation of reactive oxygen species and a biological system's ability to readily detoxify the reactive intermediates or to repair the resulting damage. Disturbances in the normal redox state of cells can cause toxic effects through the production of peroxides and free radicals that damage all components of the cell, including proteins, lipids, and DNA. Oxidative stress from oxidative metabolism causes base damage, as well as strand breaks in DNA. Base damage is mostly indirect and caused by reactive oxygen species (ROS) generated, e.g. O2− (superoxide radical), OH (hydroxyl radical) and H2O2 (hydrogen peroxide).Further, some reactive oxidative species act as cellular messengers in redox signaling. Thus, oxidative stress can cause disruptions in normal mechanisms of cellular signaling. Dr Harshavardhan Patwal , Chemically, oxidative stress is associated with increased production of oxidizing species or a significant decrease in the effectiveness of antioxidant defenses, such as glutathione.The effects of oxidative stress depend upon the size of these changes, with a cell being able to overcome small perturbations and regain its original state. However, more severe oxidative stress can cause cell death and even moderate oxidation can trigger apoptosis, while more intense stresses may cause necrosis.
Production of reactive oxygen species is a particularly destructive aspect of oxidative* stress. Such species include free radicals and peroxides. Some of the less reactive of these species (such as superoxide) can be converted by oxidoreduction reactions with transition metals or other redox cycling compounds (including quinones) into more aggressive radical species that can cause extensive cellular damage.Most long-term effects are caused by damage to DNA
The periodontium is the specialized tissues that both surround and support the teeth, maintaining them in the maxillary and mandibular bones. The word comes from the Greek terms περί peri-, meaning "around" and -odont, meaning "tooth". Literally taken, it means that which is "around the tooth". Periodontics is the dental specialty that relates specifically to the care and maintenance of these tissues. It provides the support necessary to maintain teeth in function. It consists of four principal components, namely:
Gingiva
Periodontal ligament (PDL)
Cementum
Alveolar bone proper
Dr Harshavardhan Patwal explains the diffrent cell matrix interactions with emphasis on each components is distinct in location, architecture, and biochemical properties, which adapt during the life of the structure. For example, as teeth respond to forces or migrate medially, bone resorbs on the pressure side and is added on the tension side. Cementum similarly adapts to wear on the occlusal surfaces of the teeth by apical deposition. The periodontal ligament in itself is an area of high turnover that allows the tooth not only to be suspended in the alveolar bone but also to respond to the forces. Thus, although seemingly static and having functions of their own, all of these components function as a single unit .
Porphyromonas gingivalis belongs to the phylum Bacteroidetes and is a nonmotile, Gram-negative, rod-shaped, anaerobic, pathogenic bacterium. It forms black colonies on blood agar.
It is found in the oral cavity, where it is implicated in certain forms of periodontal disease, as well as in the upper gastrointestinal tract, the respiratory tract, and the colon. It has also been isolated from women with bacterial vaginosis. Collagen degradation observed in chronic periodontal disease results in part from the collagenase enzymes of this species. It has been shown in an in vitro study that P. gingivalis can invade human gingival fibroblasts and can survive in them in the presence of considerable concentrations of antibiotics.P. gingivalis also invades gingival epithelial cells in high numbers, in which cases both bacteria and epithelial cells survive for extended periods of time. High levels of specific antibodies can be detected in patients harboring P. gingivalis. Dr Harshavardhan Patwal , explains the various enzymes enzyme peptidyl-arginine deiminase, which is involved in citrullination.[4] Patients with rheumatoid arthritis have an increased incidence of periodontal disease, and antibodies against the bacterium are significantly more common in these patients.
P. gingivalis is divided into K-serotypes based upon capsular antigenicity of the various types.
Influence of systemic disorders on periodontal diseases is well established. However, of growing interest is the effect of periodontal diseases on numerous systemic diseases or conditions like cardiovascular disease, cerebrovascular disease, diabetes, pre-term low birth weight babies, preeclampsia, respiratory infections and others including osteoporosis, cancer, rheumatoid arthritis, erectile dysfunction, Alzheimer's disease, gastrointestinal disease, prostatitis, renal diseases, which has also been scientifically validated. This side of the oral-systemic link has been termed Periodontal Medicine and is potentially of great public health significance, as periodontal disease is largely preventable and in many instances readily treatable, hence, providing many new opportunities for preventing and improving prognosis of several systemic pathologic conditions. in this power point Dr Harshavardhan Patwal , highlights the importance of prevention and treatment of periodontal diseases as an essential part of preventive medicine to circumvent its deleterious effects on general health.
ggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans) is a Gram-negative, facultative nonmotile, rod-shaped oral commensal often found in association with localized aggressive periodontitis, a severe infection of the periodontium, although it is also associated with nonoral infections. Its role in periodontitis was first discovered by Danish-born periodontist Jørgen Slots, a professor of dentistry and microbiology at the University of Southern California School of Dentistry.
'Bacterium actinomycetem comitans' was described by Klinger (1912) as coccobacillary bacteria isolated together with Actinomyces from actinomycotic lesions of man. It was reclassified as Actinobacillus actinomycetemcomitans by Topley & Wilson (1929) and as Haemophilus actinomycetemcomitans by Potts et al. (1985). The species has attracted attention because of its association with localized aggressive periodontitis. is explained here by Dr Harshavardhan Patwal
T-cells is explained with a emphasis with humoral and adaptive immunity . And the diffrent subsets of t cells are well explained by Dr Harshavardhan Patwal here .
Here saliva as a diagnostic biomarker has been explained via this powerpoint . extraction of saliva and diagnostic equipments and techniques are explained here by Dr Harshavardhan Patwal
explained here is bone loos and patterns of bone loos in alveolar bone to various insults . Dr Harshavardhan pawal also gives emphasis on rate on bone loss and radius of action .
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
NVBDCP.pptx Nation vector borne disease control programSapna Thakur
NVBDCP was launched in 2003-2004 . Vector-Borne Disease: Disease that results from an infection transmitted to humans and other animals by blood-feeding arthropods, such as mosquitoes, ticks, and fleas. Examples of vector-borne diseases include Dengue fever, West Nile Virus, Lyme disease, and malaria.
New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
New Drug Discovery and Development .....NEHA GUPTA
The "New Drug Discovery and Development" process involves the identification, design, testing, and manufacturing of novel pharmaceutical compounds with the aim of introducing new and improved treatments for various medical conditions. This comprehensive endeavor encompasses various stages, including target identification, preclinical studies, clinical trials, regulatory approval, and post-market surveillance. It involves multidisciplinary collaboration among scientists, researchers, clinicians, regulatory experts, and pharmaceutical companies to bring innovative therapies to market and address unmet medical needs.
263778731218 Abortion Clinic /Pills In Harare ,sisternakatoto
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Acute scrotum is a general term referring to an emergency condition affecting the contents or the wall of the scrotum.
There are a number of conditions that present acutely, predominantly with pain and/or swelling
A careful and detailed history and examination, and in some cases, investigations allow differentiation between these diagnoses. A prompt diagnosis is essential as the patient may require urgent surgical intervention
Testicular torsion refers to twisting of the spermatic cord, causing ischaemia of the testicle.
Testicular torsion results from inadequate fixation of the testis to the tunica vaginalis producing ischemia from reduced arterial inflow and venous outflow obstruction.
The prevalence of testicular torsion in adult patients hospitalized with acute scrotal pain is approximately 25 to 50 percent
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
Couples presenting to the infertility clinic- Do they really have infertility...Sujoy Dasgupta
Dr Sujoy Dasgupta presented the study on "Couples presenting to the infertility clinic- Do they really have infertility? – The unexplored stories of non-consummation" in the 13th Congress of the Asia Pacific Initiative on Reproduction (ASPIRE 2024) at Manila on 24 May, 2024.
Knee anatomy and clinical tests 2024.pdfvimalpl1234
This includes all relevant anatomy and clinical tests compiled from standard textbooks, Campbell,netter etc..It is comprehensive and best suited for orthopaedicians and orthopaedic residents.
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
2. CONTENTS
INTRODUCTION
TERMINOLOGY
CENTRAL DOGMA
STRUCTURE OF GENE
STUCTURE OF DNA
STUDY DESIGNS
STUDIES PERTAINING TO:
◦ CHRONIC PERIODONTITIS
◦ AGGRESSIVE PERIODONTITIS
◦ IMPLANTS
EPIGENETICS
FUTURE PROSPECTS
3. INTRODUCTION
Genetics is defined as the science of heredity .
The word GENETICS was coined by William Bateson
in 1907
In 1903 , Walter Sutton and Theodor Boveri
independently proposed that chromosomes carry the
hereditary factors.
Chromosomal theory of inheritance-Chromosomes
contain the DNA which is the genetic material
Gregor John Mendel is the father of genetics
4. INTRODUCTION
Mendels laws of heredity;
Law of segregation -the character of an organism are
determined by pairs of factors of which only one can be
present in each gamete.
Law of independent segregation-when two or more
pairs of characters are brought together in a crossover
,they segregate independently of each other.
Periodontitis is a multifactorial disease. While microbial
and other environmental factors are believed to initiate
and modulate periodontal disease progression, there
now exists strong supporting evidence that genes play
a role in the predisposition to and progression of
periodontal diseases.
5. TERMINOLOGY
Allele – one of several possible alternative forms of a given gene
differing in DNA sequence assumed to arise by mutation and often
affecting the function of a single product. Humans carry two sets of
chromosomes, one from each parent. Single nucleotide
polymorphisms may render two sets of equivalent genes different.
Alternative splicing – the generation of multiple protein isoforms from
a single gene via the splicing together of nonconsecutive exons during
RNA processing of some but not all of RNA transcripts. Believed to the
mechanism involved with the high number of proteins produced from a
smaller number of genes in humans.
Autosome – chromosomes other than sex chromosomes.
Autosomal dominant – the dominant effect of one gene located on an
autosome regardless of the presence of the other, normal copy.
Autosomal recessive – A gene on an autosome that is required in two
copies to be active in an individual. An individual who carries two such
copies of the same abnormal gene will be subjected to effects from that
gene.
6. Complementary DNA (cDNA) – the DNA sequence
produced by the enzyme called reverse transcriptase from
messenger RNA. Very frequently used in cloning
experiments.
Chromosome – a nuclear structure carrying genetic
information arranged in a linear sequence. Humans have 23
pairs (including a pair of sex chromosomes XX or XY).
Chromatin : Condensation of the DNA with histones and
other chromosomal proteins.Chromatin is further organized
into chromosomes.
Cloning – the generation of sufficient copies of a target DNA
sequence that allows it to be sequenced or studied further.
Dizygotic twin – fraternal twins as a result of fertilization of
two separate eggs. They are no more similar genetically than
are siblings.
Exon – the expressed portion of DNA or RNA that will
ultimately be translated into protein. Multiple exons are
7. Frameshift mutation – A type of mutation as a result of an insertion
or deletion of one or more nucleotides into a gene causing the
coding regions to be read in the wrong frame.
Gene – a hereditary unit that occupies a specific position (locus)
within a genome or chromosome that has one or more specific
effects upon the phenotype of the organism.
Gene expression – the process involving use of the information in a
gene via transcription and translation leading to production of a
protein affecting the phenotype of the organism determined by that
gene.
Genetic code – in RNA and DNA, the consecutive nucleotide triplets
(codon) that specify the sequence of amino acids for protein
synthesis (translation).
Genome – a term used to refer to all the genes carried by an
individual or cell.
Genotype – the genetic makeup of an organism or cell distinct from
its expressed features or phenotype.
8. Homozygous – the presence of identical alleles of one or more
specific genes (e.g. A/A).
Heterozygous – the presence of differing alleles of one or more
specific genes (e.g. A/B).
Intron – the intervening (non-coding) portion of DNA or RNA that is
removed during RNA processing.
Isoforms – a protein with equivalent function and similar or
identical sequence but derived from a different and usually tissue-
specific gene.
Linkage – the tendency for certain genes to be inherited together
due to their presence on the same chromosome.
Linkage disequilibrium – the occurrence of some genes together
more often than would be expected by random distribution.
Locus (plural loci) – the physical location a gene occupies within a
chromosome or portion of genomic DNA.
9. Monozygotic twin – identical twins having identical sets of nuclear genes
as a result of separation of blastomeres.
Mutation – alteration of the genomic sequence compared to a reference
state. Not all mutations have harmful events (silent mutation).
Phenotype – the observable characteristics displayed by an organism as
influenced by environmental factors and independent of the genotype of the
organism.
Polymorphism – a region on the genome that varies between individual
members of a population present in a significant number of individuals.
Single nucleotide polymorph (SNP) – a polymorphism caused by the
change in a single nucleotide believed to be the most common genetic
variation between individual humans.
Splicing – the removal of introns from transcribed RNAs. The removal of
exons results in the formation of ‘splice variants’ or ‘alternatively spliced’
protein isoforms allowing different proteins to be produced from the same
initial RNA or gene.
X-linked disease – a disease of genetic origin as a result of a mutation on
the X-chromosome.
Wild type – the non-mutated, naturally-occurring form of a gene.
10. Diseases with etiologies that include both genetic and
environmental factors are refferred to as multifactorial.
Genetic marker refers to any gene or nucleotide sequence
that can be mapped to a specific location or region on a
chromosome.
Trait and disease might be caused by a single gene
(monogenic), several genes (oligogenic), or many genes
(polygenic).
In monogenic disorders, genes are referred to as causative
because almost everyone with the mutation develops the
condition.
Environmental factors generally play a minor role in
determining the phenotype. In contrast, genes involved in
complex multifactorial disease are called susceptibility genes.
11. HUMAN GENOMIC PROJECT
Early in 2001, man heralded one of the greatest
scientific achievements-a draft of the human
genome.
The human genome contains 30,000-40,000
genes.(Baltimore,2001)
In periodontics genetics of both humans and
pathogens and the interaction between them is
studied.
Presently the complete sequence of P.gingivalis
has been sequenced.
12.
13. CHROMOSOME
Waldeyer in 1888 coined the term
chromosome
Chromosome consists of:
70%-protein
20%-DNA
10%-RNA
14. GENE
1st proposed by MENDEL in 1865 he
called it as factor .
The word gene was coined by
JOHANNSON in 1909
15. Promoter – Sequence of nucleotide left (upstream) of the
coding region starting with nucleotide position -1(not as
triplets)
Coding region –Reading frame starting at nucleotide Position
+1 containing triplets or codon.
Exons – (true coding region ) - nucleotide bases
contained in noncontiguous segments called the
EXONS(expressed sequences).
INTRONS(non coding region) - Exons are separated by
other sequences not present in mature mRNA called
INTRONS (intervening sequences).
23. TRANSCRIPTION FACTORS:
CLASSIFIED
Based on action (Papavassiliou,1995)
1. Basal factors – To initiate transcription on the correct site.E.g.., TATA
box-binding proteins (TBP), Polymerase II Transcription factors
(TFIIA,TF IIB,TFIIE,TFIIF).
2. Upstream factors – recognize specific DNA elements located
upstream of the transcription start site.
3. Inducible factors - important regulators of gene transcription, eg
hormones, growth factors act through this
24. Based on structure(Johnson &
McKnight,1989)
1. Zinc finger proteins e.g.steroid receptors
zinc ion bound to 2 cysteines and 2 histidines
2. Leucine zipper proteins
products of c-fos and c-jun protooncogenes
3. Homeodomain proteins
4. Helix-loop-helix(HLH) family proteins – important
in the regulation of metabolism, cell differentiation
37. The ribosome reads 3 nucleotides at a time (CODON).The ribosome
looks for the start codon where it begins building the aminoacid
chain.
There are 64 possible codons. One amino acid may be specified by
one or more codons.
Three codons do not specify any amino acid, they are stop codons.
38. tRNA’s have an ANTICODON on one end and an AMINOACID on the
other.
The anticodon dictates which aminoacid it carries to the ribosome.
The aminoacids are transferred to the ribosome by t-RNA molecules.
39. The ribosome reads the next codon and another tRNA with anticodon binds.
40. POST-TRANSLATIONAL MODIFICATION
Protein folding and glycosylation
Folding of nascent polypeptides into 3-
dimensional structures is assisted by accessory
proteins and disulphide linkages, molecular
chaperones(BIP,HSP,FO).
Modifications such as hydroxylation of
proline and hydroxyl residues in collagen can
occur only on unfolded polypeptides.
41. SORTING OF PROTEINS
The movement of protein from the site of
protein synthesis to a different destination
is known as targeting or
sorting.(Heijne,1990)
TRANSLOCATION
The movement of polypeptide across
membranes of organelles and RER .This is
followed by secretion of protein and then
undergoing removal of extra
sequences(Processing)
42. FACTORS THAT AFFECT PROTEIN
PRODUCTION
1. DNA methylation – mechanism by which gene
expression is regulated.(Eden,1994)
2. Methylated genes are inactive and the promoter activity
is inhibited.
3. Most environmental and physiological mediators affect
gene transcription by modifying the synthesis of
transcription factors.(Maniatis et al,1987)
Synthesis of new transcription factors when needed
Covalent modification of aminoacids and phosphorylation of
certain residues modifies the binding of this particular
transcription factor to the DNA response sequences.
Many hormones, cytokines act by phosphorylation of the
transcription factor API
Steroid hormones, Vit D, sex hormones bind to their respective
cytoplasmic DNA binding receptors.
43. GENETIC VARIANCES
Genes can exist in different forms or
states (alleles)
Allelic variants of a gene differ in their
nucleotide sequences.
44. ALLELE
A variant of the DNA sequence at a given
locus is called an allele.
The genotype for each gene comprises
the pair of alleles present at that locus
Allele that leads to an observable
phenotype –dominant allele
Allele does not lead to an
observable phenotype- recessive
allele.
45. MUTATION
Mutation can cause variation in
alleles.
• A mutation is defined as a heritable
alteration or change in the genetic
material.
46. Basis of classification Types
Origin Spontaneous
•Tautomerism
•Depurination
•Deamination
•Slipped Strand Pairing
Induced
•Chemical
•Radiation
•Viral infections
Cell type Germ line – reproductive cell(Hereditary disease)
Somatic- somatic cell(Cancer,Congenital malformations)
Stability Fixed
Substitution-base pair change
Transition - Pyrimidine to pyrimidine (T or C) / purine to
purine (A or G).
Transversion- Pyrimidine to purine / purine to
pyrimidine
Insertion: extra nucleotide
Deletion- missing nucleotide.
Dynamic
Trinucleotide repeat mutation
47. Basis of classification Types
Effect on translation Synonymous mutation
Silent
Non Synonymous mutation
Missense
Nonsense
Frameshift
Substitution/Addition of
nucleotide
Point Mutation
Silent
Missense
Nonsense
Frameshift Mutation
Insertion
Deletion
Effect on function Loss of function- Null
Neomorphic-Gain in function
Antimorphic mutation
Hypomorphic- reduced function.
Hypermorphic- increased function
Ectopic expression
Lethal mutation
Reversion
48. Polymorphism
Allele is a variant form of a gene
The coexistence of multiple alleles at a locus is called “Genetic
polymorphism” when they occur at more than one percent in a
population.
49. Types of Polymorphism
SNP: Single Nucleotide polymorphisms-
The change in a single nucleotide found
at a single location is called SNP.
VNTR: Variable number of Tandem
Repeats.-Repeated base patterns
consisting of several hundreds of base
pairs
STR: Simple Tandem repeats.-2,3 or 4
nucleotide repeats on a variable number
of locations.
51. Polymorphism Vs Mutation
MUTATIONS POLYMORPHISMS
Here a single gene locus causing
mutation has a major
physiological impact & considered
to be deterministic to disease.
Here the gentic alteration that
contributes to complex disease
has smaller effect.
Seen less commonly in the
population
Atleast or more than 1% of
population.
Mutation have causually linked
with Mendelian disease.
Here mutation is not causually
linked to disease but alleles are
seen more frequently in disease
individuals.
One-to-one correlation of a
mutation & disease can be
established.
No one-to-one correlation.
52. 3 Major Categories of Genetic
Disorders
1. Major chromosomal disorders
2. Mendelian disorders
3. Non-Mendelian disorders
53. Major chromosomal disorders
Numerical Abnormality
◦ Aneuploidy
◦ Polyploidy
◦ Monosomy
◦ Trisomy
◦ Mosaicism-2 or more population of cells
Structural Abnormality
◦ Translocation
◦ Isochromosomes
◦ Inversions
◦ Deletion
◦ Insertion
◦ Ring Chromosome
54. "Simple" Mendelian diseases
Diseases that follow predictable and generally
simple patterns of transmission have been called
"Mendelian" conditions. Genes involved are called
as causative genes.
The name reflects the fact that these diseases
occur in simple patterns in families, and in most
cases a single gene locus is the major determinant
of the clinical disease phenotype.
These diseases follow a classic Mendelian mode of
inheritance:
Autosomal dominant-Huntington disease
Autosomal recessive-Cystic Fibrosis
x-linked dominant- Aicardi Syndrome
x-linked recessive - Hemophilia A
55. SYNDROMES ASSOCIATED WITH
PERIODONTITIS(Simple Mendelian Diseases)
Condition Biochemical/tissue defect Inheritance Periodontal
Disease
Papillon Lefevre Syndrome Cathepsin C Autosomal
recessive
AP
Halm Munk Syndrome Cathepsin C Autosomal
recessive
AP
Ehlers Dalnos Syndrome Type
IV
Collagen Autosomal
Dominant
AP
Ehlers Dalnos Syndrome 8 Collagen Autosomal
dominant
AP
Cyclic Neutropenia Neutrophil Elastase Autosomal
Dominant
AP, CP
Chronic Familial Neutropenia Defect unknown Autosomal
dominant
AP, CP
Chediak Higashi Syndrome Lysosomal trafficking
regulator gene
Autosomal
recessive
AP
Congenital disorder of
glycosylation Type 11C
Glucose diphosphate fucose
transporter 1
Autosomal
recessive
AP
Leukocyte adhesion deficiency Leukocyte chain adhesion Autosomal AP, CP
56. Multifactoprial Diseases or
Complex" diseases
Genetically complex diseases are
much more prevalent (>1% of
population) and is caused by
susceptibility genes
This type is the result of the interaction
of multiple different gene loci.
Additionally, environmental factors are
important in the disease process.
Example:Periodontitis,
57. STUDY DESIGNS
1. Familial Aggregation
2. Segregation Analysis
3. Twin Studies
4. Linkage Analysis
5. Association Studies
58. Familial Aggregation
Familial aggregation of a trait or disease can
suggest genetic etiology.
However, families also share many aspects
of a common environment, including diet and
nutrition, exposures to pollutants, and
behaviors such as smoking (active and
passive).
Certain infectious agents may cluster in
families. Thus, familial aggregation may result
from shared genes, shared environmental
exposures and similar socioeconomic
influences.
To determine the evidence for genetic factors
in familial aggregation of a trait, more formal
genetic studies are required.
59. Familial Aggregation
AUTHOR,YEAR SUBJECTS FINDINGS
Chung 1977 In a Hawaii racially mixed
populations. A total of 939
subjected from 241 nuclear
families was included in the
analysis.
Sex, age, years of education and
smoking were significantly
associated. No significant
contribution of genotype to
susceptibility for periodontitis .It was
concluded that common family
environment was a determining
factor of variability in pdl health.
Beaty et
al.1993
Studied familial aggregation of
plaque index, gingival index
and attachment loss. The
sample included 178 volunturs
from 75 families (mostli
African-Americans)and was
mainly block females < 40
years.
Genotype influences plaque index,
but not GI and attachment loss.
Mother offspring correlation was
stronger than father for both GI and
attachment loss.
60. Segregation analysis
Pattern of transmission of disease through generation is studied in
different families.
It is compared with those expected under various models of inheritance
to select the best fitting model.
The pattern in which disease is transmitted across generations
depends on whether disease alleles:
• Lie on autosome/sex chromosomes
• Dominant or recessive
• Fully or partially penetrant.
Adv: Can assess whether the disease gene is autosomal or sex linked,
recessive or dominant.
Limitation:
1. It has low power to resolve heterogeneity (Multiple causes)
2. Cannot distinguish between genetic & environmental influences.
3. Does not provide information about specific genes
61.
62. Author Study Results
Beaty TH et al 1987 Proband with Juvenile
periodontitis- 28 families.
Different models of
inheritance studied
Autosomal recessive mode
of inheritance for JP
Hart TC, Marazita ML et al
1992
Re-interpretation of X-
linked mode of inheritance
among Juvenile
periodontitis
Female ascertainment bias
and lack of father to son
transmission interpreted in
a different way.
Marazita ML et al 1994 EOP- 104 probands- 100
families, blacks and non
blacks families
Autosomal dominant mode
of inheritance among
blacks and non blacks with
70% penetrance
Marazita ML et al 1996 Segregation analysis of
IgG2 levels in EOP among
african americans and
caucasians
Autosomal co-dominant
mode of inheritance
Hodge PJ et al 2000 Caucasian family from
Europe with EOP
Autosomal dominant or X-
linked mode of inheritance
De Carvalho FM et al 2009 Aggressive periodontitis-
Brazilian population
Semi general mode of
transmission: few loci with
small effects contribute to
63. Twin Studies
Influence of genetic and environmental factors
on complex diseases can be estimated.
Sir Francis Galton in 1875 was the first scientist
to use this concept.
Monozygotic twins: 100% similar genetic make
up.
Dizygotic twins: 50% similar genetic make up
Heritability estimate can be made.
Concordance – degree of similarity between
twins in one or more characteristics.
Discordance- degree of dissimilarity between
twins in one or more characteristics.
64. Two Types:
1. Classic twin study -monozygotic and
dizygotic twins are Reared together
and compared.
2. Monozygotic twins reared
apart:MZA-Effects of shared genes
without the confounding effects of a
common family environment
65. Author Study Results
Corey LA et al 1993 4908 twin pairs:
questionnaire based
study- history of
periodontal disease. 116
MZ twin pairs and 233
DZ pairs
Concordance rate of MZ
twins: 0.23 to 0.38 and
for DZ twins: 0.08 to 0.16
Michalowicz et al 1999 169 twin pairs: presence
of P.ging, A.a,
P.intermedia,
E.corrodens,
F.nucleatum
P.ging-11%, A.a- 22%,
P.intermedia- 19%,
E.corrodens- 0.34%,
F.nucleatum-40%. No
difference in
concordance rates
between MZ and DZ
pairs.
Michalowicz BS et al
2000
64 MZ, 53 DZ twin pairs:
influence of smoking and
utilization of dental
services
Chronic periodontitis-
50% heritability
independent of smoking
and dental services.
66. Linkage Analysis
Used to map disease allele to specific regions on the chromosomes.
Linkage studies use sets of families with multiple affected
individuals.
Complex statistical models are used to determine whether the
marker allele and disease co segregate in the families under a
given inheritance model.
Linkage can be detected if the marker and disease alleles are
within 20-30 centimorgans of one another.
LOD(Logaritham of odds) score - Compare the likelyhood of two
genes are indeed linked to the likely hood of observing this data purely
by chance.
Positive LOD score- presence of linkage
Negative LOD score-less likely
67. Linkage studies usually start by identifying markers (SNPs) on a section of a
chromosome and then narrowing the region down until the gene or gene
variant of interest is identified.
DISADVANTAGE-Complex diseases are due to combined effects of
“multiple genes of minor effect”.
68. Example:
Author Study Results
Boughman et al 1986 Localized Aggressive
periodontitis
AgP segrgates with
dentinogenesis
imperfecta. Localized to
long arm of chromosome
4 near the gene for
dentinogenesis
imperfecta.
Li Y et al 2004 Localized Aggressive
periodontitis
Disease gene localized
to chromosome 1.
Tabeta K et al 2009 Linkage disequilibrium
block analysis- SNP’s
and Microsatellites in
chromosome 19
A single microsatellite
marker allele 17 of 1902
G 31 on chromosome
19- associated with
severe chronic
periodontitis
69. Association Studies
Frequency of marker alleles at a given locus is
compared between subjects with disease(cases) and
healthy controls sampled from same population .
◦ Population based approaches
◦ Family based approaches
Association suggest that the presence of an
allele confers risk for disease within a defined
environment.
Limitation –Association does not necessarily imply a
biologic link between the disease and the tested allele.
70. FAMILY STUDIES
AUTHOR,YEAR SUBJECTS FINDINGS
Chung 1977 In a Hawaii racially mixed
populations. A total of 939
subjected from 241 nuclear
families was included in the
analysis.
Sex, age, years of education and
smoking were significantly
associated. No significant
contribution of genotype to
susceptibility for periodontitis .It was
concluded that common family
environment was a determining
factor of variability in pdl health.
Beaty et
al.1993
Studied familial aggregation of
plaque index, gingival index
and attachment loss. The
sample included 178 volunturs
from 75 families (mostli
African-Americans)and was
mainly block females < 40
years.
Genotype influences plaque index,
but not GI and attachment loss.
Mother offspring correlation was
stronger than father for both GI and
attachment loss.
71. TWIN STUDIES
AUTHOR,YEAR SUBJECTS FINDINGS
Ciancio et
al.1969
Investigated levels of gingival
recession and crevice depth and
indices of gingivitis, supra gingival
plaque and calculus in 26 twin pairs
aged 12-17 years .
found no evidence of genetic
influence
Michalowicz
et al 1991
To estimate the genetic variance for
alveolar bone height. Panoramic
radiographs were obtained from 120
pairs of adult twins (mean age = 40.4
years, S.D. = 10.4 years), for
comparison of 62 pairs of MZT ,25
like-sexed DZT and 33 pairs MZA.
The intraclass correlations
MZT = 0.70, DZT = 0.52, and
MZA = 0.55. Significant
genetic variance in the
population for proportional
alveolar bone height.
Corey LA et
al 1993
4908 twin pairs: questionnaire based
study- history of periodontal disease.
(VIRGINIA)116 MZ twin pairs and
233 DZ pairs
Concordance rate of MZ twins:
0.23 to 0.38 and for DZ twins:
0.08 to 0.16
72. TWIN STUDIES
AUTHOR,YEAR SUBJECTS FINDINGS
Michalowicz
et al 1991
Examined the relative contribution of
environmental and host genetic factors to
clinical measures of periodontal disease
through the study 110 pairs of adult twins
(mean age 40.3 years), including 63 MZT
and 33 DZT and 14 MZA
Significant genetic
component for gingivitis,
PD ,CAL, plaque..
38% to 82% of the
population variance for
these periodontal
measures of disease may
be attributed to genetic
factors
Michalowicz
et al 1999
169 twin pairs: presence of P.ging, A.a,
P.intermedia, E.corrodens, F.nucleatum
P.ging-11%, A.a- 22%,
P.intermedia- 19%,
E.corrodens- 0.34%,
F.nucleatum-40%. No
difference in concordance
rates between MZ and DZ
pairs.
Michalowicz
BS et al 2000
64 MZ, 53 DZ twin pairs: influence of
smoking and utilization of dental services
Chronic periodontitis- 50%
heritability independent of
73. ASSOCIATION STUDIES
AUTHOR,YEAR SUBJECTS FINDINGS
Kornman et
al.1997
“Composite” IL-1 genotype consisting of at least
one copy of the more rare Allele at both an IL-1
& and IL – IB loci was associated with severe
periodontitis in northern European adults.
Association-18.9
Gore et
al.1998
Composite genotype in caucasians More rare IL-1β
sites were in linkage
disequilibrium,
74. ASSOCIATION STUDIES
AUTHOR,YE
AR
SUBJECTS FINDINGS
Kobayashi
et al.1997
Neutrophil IgG receptor with CP in
Japanese population
Association was found with
FCᵧRIIIb-NA2
Engebrets
on et al.
1999
IL-1 composite genotype in US
population
Elevated levels of IL-1 Beta
in GCF.
Galbreuth
et al. 1998
TNF genotypes were determined in 32
Caucasian patients with adult
periodontitis and 32 orally-healthy
matched controls, and correlated with
TNF-alpha production by oral
polymorphonuclear leukocytes (PMN)
No association between CP
and TNF-α
1 genotype was correlated
with elevated TNF-α
production by oral PMNs in
patients with advanced
disease. Polymorpheisms.
Armitage
et al 2000
Association of CP with Composite
genotype in Chinese Population
No association
76. PEDIGREE ANALYSIS
AUTHOR,YEAR SUBJECTS FINDINGS
Benjamin et
al., 1967
Twelve families (52 individuals) XD mode. The
female to male ratio
was
3:1
Butler 1969 A family The proband and his sister had JP. His
mother and maternal aunt and grandfather had
become edentulous at an early age
XD mode
Fourel, 1972 A family (more than 20 individuals) AR mode
Jorgenson et
al., 1975
A family AR mode
Melnick et al.,
1976
Two families
Family 1: five of six siblings, three of them
female, had JP
Family 2: four of eight siblings, all females, had
XD mode with
decreased
penetrance.
The female to male
77. AUTHOR,YEAR SUBJECTS FINDIN
GS
Sussman et
al., 1978
Proband, 17, female .Mother and grandmother were
affected
AD
mode
Vandesteen et
al., 1984
A family (29 individuals in the pedigree trees) The proband
and six siblings all had JP; both parents were edentulous
since early adulthood; both maternal grandparents and at
least two siblings of the mother
had been affected Paternal side: two of the fathers siblings
were affected, but the paternal grandparents were not
affected
XD
mode
Spektor et al.,
1985
One large family (40 individuals in the pedigree trees) The
proband had JP Father (healthy) mother (affected)
Twelve siblings (six affected, six
unaffected) Both maternal grandparents of the proband
had become edentulous at an early
age. Four of 10 siblings of the probands mother had EOP.
The paternal grandparents did not have EOP and
periodontitis was not unusually prevalent in the siblings of
the probands father
XD
mode
Page et al., A family (six individuals) The parents had JP in their teens, XD
78. SEGREGATION ANALYSIS
AUTHOR GENETIC ANALYSIS SUBJECTS FINDINGS
Melnick
et al.,
1976
Segregation
analysis and
pedigree analysis
Two families
Family 1: five of six siblings,three of them
female, had JP
Family 2: four of eight siblings,all females,
had JP
Caucasian & African -American
XD mode
Saxen,
1980
Simple
segregation
analysis
Thirty-one families (158 subjects: 60 parents,
64 siblings and 3 children) Neither parents
nor the children were affected with JP. 11 ⁄ 64
siblings were affected
Finnish group
AR mode
Saxen
et al.
1984
Simple
segregation
analysis
Thirty families (60 parents and 52
siblings).No parents were affected;9 ⁄ 52
siblings were affected(Finnish group)
AR mode
Beaty
et al.,
1987
Complex
segregation
analysis
Twenty-eight families (372 individuals: 62
had JP, 95 were unaffected and 215
unknown)(US Sample)
AR mode
Long Complex 33 families (199 individuals)Compared the AR mode
79. SEGREGATION ANALYSIS
AUTHOR GENETIC
ANALYSIS
SUBJECTS FINDINGS
Boughma
n et al.,
1988
Complex
segregation
analysis
28 families (372 individuals: 62 had JP,95
were unaffected and 215 unknown)(Triracial
isolate)
AR mode
Marazita
et al.,
1994
Complex
segregation
analysis
One-hundred families (631 individuals in
total)
African–Americans
Dominant
mode
with
penetranc
e of about
70%
Hodge et
al., 2000
Segregation
analysis
and linkage
study
A large family (40 individuals
in the pedigree trees)
North European Caucasians
Dominant
mode
80. TWIN STUDY
No twin study on aggressive
periodontitis has been reported
81. LINKAGE ANALYSIS
AUTHOR GENETIC
ANALYSIS
SUBJECTS FINDINGS
Boughma
n et al.,
1988
Linkage
study
A large, five-generation family
from southern Maryland
(more than 70 individuals)
An AD mode of JP: its
localization to chromosome 4
and linkage to dentinogenesis
imperfecta and Gc
Hart et
al., 1993
Linkage
study
Fifteen African–American and
four Caucasian families (228
individuals)
Exclusion of the 4q candidate
region for EOP
Li et al.,
2004
Linkage
study
Four African–American
families (28 subjects)
L-AgP is linked to human
chromosome 1q25
82. ASSOCIATION ANALYSIS
AUTHOR GENETIC
ANALYSIS
SUBJECTS FINDINGS
Diehl et
al.,1999
Family-
based
associatio
n
study
Twenty-eight African–
American and seven
Caucasian–American families
(285 individuals with DNA
available for 246)
Allele 1 of both interleukin-
1A-889 and interleukin-1B
+3953 was transmitted more
frequently with the EOP
phenotype
Ren et
al.2009
Family-
based
associatio
n
study
Seventy-three nuclear
families
(DNA available for 204
subjects) from China
Allele A of S100A8 gene SNP
rs3795391 (A ⁄ G) showed
significantly preferential
transmission to the AgP-
affected
individuals in the
additive genetic model
83. GENETICS & IMPLANTS
Very few studies have been reported addressing the influence of
genetics on implant survival.
Wilson et al.1999 . Studied the effects of the IL-1 genotype,smoking
status, and patient’s age on failed or failing implants was compared to
successfully integrated implants .Statistical testing failed to indicate a
relationship between implant failure, age, or IL-1 genotype status.
Rogers et al.2003. also failed to demonstrate a relationship between
implant failure and the IL-1A (-899), IL-1B (+3953) composite genotype
in Caucasian patients.
[
Systematic review by Huynh et al.2007on the role of the composite
interleukin-1alpha and interleukin-1beta polymorphisms and their
natural specific inhibitor, interleukin-1 receptor antagonists, with
respect to the development of periodontitis and periodontal therapy ,
no conclusive evidence can be attributed to the genetic traits.
84. EPIGENETICS
Epigenetics is the study of changes produced in gene
expression caused by mechanisms other than changes in the
underlying DNA sequence 2 Major Mechanism are:
◦ DNA Methylation
◦ Histone Modification
The hypo or hyper methylation of sites upstream of promoter region
of cytokine genes can regulate the gene expression thereby
resulting in increased production of the cytokines.
Chung et al ,2003 has demonstrated for TNF alpha in Rheumatoid
arthritis.
Oral infection may also lead to epigenetic alterations, locally within
gingival tissue or more globally with widespread effects. Technology
is available to determine genomic-wide epigenetic changes that can
be applied to study tissues at the biofilm interface to compare
diseased tissue to healthy control tissue.
85. Susceptibility profile
Combination of gene polymorphisms
constitute a profile.
Help to classify patients as low,
medium and high risk.
Already in application in systemic
disease such as Alzheimer’s disease .
FUTURE PROSPECTS
86. Screening for risk assessment
Aggressive periodontitis: screening
the siblings of “probands” for
aggressive periodontitis.
87. References
Clinical Periodontology. Carranza, 10th edition.
Clinical Periodontology and Implant dentistry. Lindhe,
4th edition.
Biology of the Periodontal Connective
Tissues.Naraynan AS, Bartold PM
Genes and gene polymorphisms associated with
periodontal disease. Crit Rev Oral Biol Med. 2003:
14(6); 430-449.
The genetic basis of periodontitis. Kinane DF, Hart TC.
Periodontology 2000, 2005; Vol 39: 91-117.
88. Genetic study of families affected with
aggressive periodontitis.Huanxin et al.
Periodontology 2000, 2011; Vol 56: 87-101.
The genetic relationship to periodontal
disease.Nares.S. Periodontology 2000, 2003;
Vol 32: 36-49.
Epigenetic Regulation of gene expression in
the inflammatory response and relevance to
common diseases.Wilson AG.J Periodontal
2008;79:1514-1519.
89. Gene polymorphisms in periodontal health and
disease. Perio-2000. 2006: 40; 94-106.
Clinical utility of a genetic susceptibility test for severe
chronic periodontitis – A critical evaluation. JADA
2002: 133; 452-459.
Implications of Genetic Technology for the
Management of Periodontal Diseases. JP 2005: 76;
850-857.