1. Odontoblasts differentiate from dental papilla cells under the influence of inner dental epithelium and form dentin.
2. Initial odontoblast differentiation requires a fibronectin-rich substratum, aperiodic fibrils, TGF-β1, calcium, and enamel matrix proteins.
3. Mature odontoblasts are polarized cells that synthesize and secrete dentin matrix proteins such as collagen type I, dentin sialophosphoprotein, dentin phosphoprotein, and proteoglycans via the rough endoplasmic reticulum, Golgi complex, and secretory granules.
Protein targeting or protein sorting is the mechanism by which a cell transports to the appropriate positions in the cell or outside of it. Both in prokaryotes and eukaryotes, newly synthesized proteins must be delivered to a specific sub-cellular location or exported from the cell for correct activity. This phenomenon is called protein targeting. Protein targeting is necessary for proteins that are destined to work outside the cytoplasm.This delivery process is carried out based on information contained in the protein itself. Correct sorting is crucial for the cell; errors can lead to diseases. In 1970, Günter Blobel conducted experiments on the translocation of proteins across membranes. He was awarded the 1999 Nobel Prize for his findings. He discovered that many proteins have a signal sequence, that is, a short amino acid sequence at one end that functions like a postal code for the target organelle.
Protein targeting or protein sorting is the mechanism by which a cell transports to the appropriate positions in the cell or outside of it. Both in prokaryotes and eukaryotes, newly synthesized proteins must be delivered to a specific sub-cellular location or exported from the cell for correct activity. This phenomenon is called protein targeting. Protein targeting is necessary for proteins that are destined to work outside the cytoplasm.This delivery process is carried out based on information contained in the protein itself. Correct sorting is crucial for the cell; errors can lead to diseases. In 1970, Günter Blobel conducted experiments on the translocation of proteins across membranes. He was awarded the 1999 Nobel Prize for his findings. He discovered that many proteins have a signal sequence, that is, a short amino acid sequence at one end that functions like a postal code for the target organelle.
I have tried to make a precise presentation on protein transport, targeting and sorting into organelle's other than nucleus. Hope this might help you. Comments are welcome.
Protein targeting or protein sorting is the biological mechanism by which proteins are transported to their appropriate destinations in the cell or outside it. Proteins can be targeted to the inner space of an organelle, different intracellular membranes, plasma membrane, or to exterior of the cell via secretion.
Protein targeting or protein sorting is the biological mechanism by which proteins are transported to their appropriate destinations in the cell or outside it. Proteins can be targeted to the inner space of an organelle, different intracellular membranes, plasma membrane, or to exterior of the cell via secretion.
Epidermal Growth Factor use in Diabetic Foot UlcersG H PRABHU
EGF is used by many diabetologists to treat Diabetic Foot Ulcers. If used early EGF can prevent progression of DFU resulting in amputations and related morbidity and mortality.
I have tried to make a precise presentation on protein transport, targeting and sorting into organelle's other than nucleus. Hope this might help you. Comments are welcome.
Protein targeting or protein sorting is the biological mechanism by which proteins are transported to their appropriate destinations in the cell or outside it. Proteins can be targeted to the inner space of an organelle, different intracellular membranes, plasma membrane, or to exterior of the cell via secretion.
Protein targeting or protein sorting is the biological mechanism by which proteins are transported to their appropriate destinations in the cell or outside it. Proteins can be targeted to the inner space of an organelle, different intracellular membranes, plasma membrane, or to exterior of the cell via secretion.
Epidermal Growth Factor use in Diabetic Foot UlcersG H PRABHU
EGF is used by many diabetologists to treat Diabetic Foot Ulcers. If used early EGF can prevent progression of DFU resulting in amputations and related morbidity and mortality.
WorkPlace Exchange is a platform sharing participant experiences from the largest sponsors in the country.
Latest best practices from plan sponsors across industries collected and displayed.
WorkPlace Exchange will assist firms increase participation rates and contribution rates all by way of best practices from other plan sponsors.
Dentinogenesis/certified fixed orthodontic courses by Indian dental academyIndian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Dentinogenesis/certified fixed orthodontic courses by Indian dental academyIndian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Dental pulp /certified fixed orthodontic courses by Indian dental academy Indian dental academy
Welcome to Indian Dental Academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy has a unique training program & curriculum that provides students with exceptional clinical skills and enabling them to return to their office with high level confidence and start treating patients
State of the art comprehensive training-Faculty of world wide repute &Very affordable.
This presentation gives the basic idea, about the information on the role of tyrosine kinases in cancer. I have also included a phylogenetic tree for finding the relatedness between different organisms.
Adhesive proteins are industrially important proteins which were isolated and from the mussels and they were produced using conventional methods such as natural extraction. But now this protein is produced using genetic engineering technologies. It has wide applications in various arena.
ROLE OF NEUTROPHILS IN HEALTH & DISEASE.pptxjasmine918783
The slide contains information about neutrophils, its basic structure, formation, trafficking, functions, the role of neutrophils in acute inflammation, various disorders of neutrophils, etc.
The endoplasmic reticulum is a very important part of the eukaryotic cell. It is a network of membranes that performs different functions depending on its type and location. There are two types of endoplasmic reticulum: rough and smooth. The rough endoplasmic reticulum has ribosomes attached to it, which are the sites of protein synthesis. The smooth endoplasmic reticulum does not have ribosomes, but it is involved in lipid synthesis, hormone production, and detoxification. The endoplasmic reticulum is connected to the nuclear membrane and the Golgi apparatus, and it helps transport proteins and lipids within the cell
A presentation on the topic of microscopic section of gingiva. This topic is mostly looked on by periodontists. A very important chapter in the speciality in dentistry of periodontology and implantology department. Basic understanding of microscopic features and clinical features of gingiva is an important topic for post graduate as well as undergraduate students in the dental field.
Cytoskeleton of a cell is made up of microfilaments, microtubules and intermediate filaments. Keratins are diverse proteins. These intermediate filaments maintain the structural integrity of the keratinocytes. The word keratin covers these intermediate filament-forming proteins within the keratinocytes. They are expressed in a specific pattern and according to the stage of cellular differentiation. They always occur in pairs. Mutations in the genes which regulate the expression of keratin proteins are associated with a number of disorders which show defects in both skin and mucosa. In addition, there are a number of disorders which are seen because of abnormal keratinization. These keratins and keratin-associated proteins have become important markers in diagnostic pathology. This review article discusses the classification, structure, functions, the stains used for the demonstration of keratin and associated pathology. The review describes the physiology of keratinization, pathology behind abnormal keratin formation and various keratin disorders.
Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
As flu season approaches, health officials in Bangalore, Karnataka, are urging residents to get their flu vaccinations. The seasonal flu, while common, can lead to severe health complications, particularly for vulnerable populations such as young children, the elderly, and those with underlying health conditions.
Dr. Vidisha Kumari, a leading epidemiologist in Bangalore, emphasizes the importance of getting vaccinated. "The flu vaccine is our best defense against the influenza virus. It not only protects individuals but also helps prevent the spread of the virus in our communities," he says.
This year, the flu season is expected to coincide with a potential increase in other respiratory illnesses. The Karnataka Health Department has launched an awareness campaign highlighting the significance of flu vaccinations. They have set up multiple vaccination centers across Bangalore, making it convenient for residents to receive their shots.
To encourage widespread vaccination, the government is also collaborating with local schools, workplaces, and community centers to facilitate vaccination drives. Special attention is being given to ensuring that the vaccine is accessible to all, including marginalized communities who may have limited access to healthcare.
Residents are reminded that the flu vaccine is safe and effective. Common side effects are mild and may include soreness at the injection site, mild fever, or muscle aches. These side effects are generally short-lived and far less severe than the flu itself.
Healthcare providers are also stressing the importance of continuing COVID-19 precautions. Wearing masks, practicing good hand hygiene, and maintaining social distancing are still crucial, especially in crowded places.
Protect yourself and your loved ones by getting vaccinated. Together, we can help keep Bangalore healthy and safe this flu season. For more information on vaccination centers and schedules, residents can visit the Karnataka Health Department’s official website or follow their social media pages.
Stay informed, stay safe, and get your flu shot today!
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
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
Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
Follow us on: Pinterest
Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
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.
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.
Prix Galien International 2024 Forum ProgramLevi Shapiro
June 20, 2024, Prix Galien International and Jerusalem Ethics Forum in ROME. Detailed agenda including panels:
- ADVANCES IN CARDIOLOGY: A NEW PARADIGM IS COMING
- WOMEN’S HEALTH: FERTILITY PRESERVATION
- WHAT’S NEW IN THE TREATMENT OF INFECTIOUS,
ONCOLOGICAL AND INFLAMMATORY SKIN DISEASES?
- ARTIFICIAL INTELLIGENCE AND ETHICS
- GENE THERAPY
- BEYOND BORDERS: GLOBAL INITIATIVES FOR DEMOCRATIZING LIFE SCIENCE TECHNOLOGIES AND PROMOTING ACCESS TO HEALTHCARE
- ETHICAL CHALLENGES IN LIFE SCIENCES
- Prix Galien International Awards Ceremony
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. Dentinogenesis
Dentin is formed by
odontoblasts that
differentiate from
ectomesenchymal
cells of dental papilla with
influence from the inner
dental epithelium
3. Differentiation of odontoblasts
(withdrawal from the cell cycle, cytological
polarization, and secretion of predentin/dentin)
Odontoblast precursor migrate from neural crest
and become part of ectomesenchymal cell .
During cap stage pre-odontoblast is
concentrated adjacent to inner enamel
epithelium and exit the cell cycle and
differentiate befor pre-ameloblasts of IEE stop
dividing.
4. REQUIREMENT OF INITIAL ODONTOBLASTIC
DIFFERENTIATION
1. Fibronectin rich substratum.---
fibronectin receptors (165-kDa protein) –
adherence appears to stabilize
cytoskeletal elements , promotes preodontoblast
polarization , and trigger other cytoplasmic process
associated with differenciation .
it also serve as reservoir for growth factors.
2. Aperiodic fibrils for regulating differentiation.
5. 2. Aperiodic fibrils for regulating differentiation.
3. Transforming growth factor β 1 ( TGF - β 1 )
Bind to fibronectin ,
Inhibits cell proliferation ,promoter of odontoblast differenciation,
Matrix synthesis.
4.Calcium –
calcium ions signals for mediating restructuring of cytoskeleton during
estalishment of of odontoblast shape ans polarity towards the IEE.
5. Enamel matrix protein –
are endocytosed in coated vesicle at odontoblast cell surface.
7. The intercellular spaces contain collagen fibres ,aperiodic
microfibrils, proteoglycans and fibronectin.
These intercellular fibres (von korff fibres) pass into
predentin between adjacent odontoblast at interruptions of
fascia occludens and fascia adherens junctions.
The RER is the major cytoplasmic organelle within active
odontoblast ..the parallel cistern occupy the supranuclear
cytoplasm.
8. Go l g i c o mp l e x …
Display morphological ( forming face )
functional polarity ( mature face)
Presecretory granules consisting of type 1
procollagen , glycoproteins, and glycoaminoglycans
develop from cisterns of mature face.
9. Ba s i c s c i e n c e
c o r r e l a t i o n ..
the complex cytoplasmic machinery operating in the
golgi complex for targeting secretory proteins to their
appropriate final destination.
Proteins are synthesized in RER and futher
transported to golgi complex where it is
posttranstionally modified ,sorted and packeged for
further transport to either secretory granules, primary
lysosome ,or cell membrane.
10. Un i d i r e c t i o n a l
a nt e r ogr a de
v e s i c ul a r t r a ns por t
11. Glycosyltransferase and glycosidases contained in the golgi
cisternae sequentially decorate the peptide backbone of the
protein by addition of the carbohydrate side chain..
1. Addtion of oligosaccharides by nitrogen linkage to asparagine..
2. Oxygen linkage at serine and threonine residues
( 2 steps process…..1. addition of N-acetyl-galactosamine
2. addition of galactose and sialic
acid
The budding process require recruitment and attachment of
specific coat proteins on the parent cisternal membrane to form
a mechanochemical “patch” capable of deforming the
membrane into a seprate vesicle.
Coatomer recruitment requires ATP, Ca2+ ,guanosine
triphosphate (GTP) ANS SEVERAL cystolic proteins.
13. Sorting products to appropriate destinations
requires specific signals to control the
docking of transport vesicles with the
correct target compartment..
This is accomplise by transmembrane
protein that act as surface markers.
They are soluble N-ethylmaleimide-
sensitive fusion attachment protein
receptors (SNAREs)
14. F O R MA T I O N , D O C K I N G
AND F US I ON OF
T RANS P ORT VESI CL ES
15. Attachment of v-snare to t-snare is monitered
and stabilized by Rab-GTP molecule present in
donor vesicle membrane.
With the help of fusion protiens
NSF-P ---- N-ethylmaleimide sensitive fusion
protein
SNAPs---- soluble NSF attachment protiens
16. Od o n t o b l a s t
s e c r e t or y
p a t h wa y
Ctv-intermediate coated transport vesicle.
CGN- cis golgi network
Psg-pre secretory granules
Tgn– trans golgi network
17. Secretory granules formation involves of condensation of
secretory product from larger condensing vacuoles
(presecretory granules ) .
Budding of membrane from the condensing vacuole continues
untill a smaller and denser secretory granules is formed..
intact microtubular system forms a radiating network
extending from the centrosome outward the cell periphery to
translocate granules to specific region of cell surface.
Further transport toward plasma membrane is dependent on
myosin
While in constitutive pathway products are
immediately exported..
18. S E CRE T I ON OF DE NT I N
MA T R I X
Preameloblast and preodontoblast express matrix
metalloproteinase 2 , an enzyme that degrade
collagen and fibronectin ,coincident with the
removal of the basal lamina .
After break up from basal lamima this newly
differntiated odontoblasts adhere to adjacent
odontoblast by stable gap junction and macula
adherens type .permitting ions and small
metabolite to cross from odontoblast to
19. odontoblast grow in length and develop large
amount of rough endoplasmic reticulum (RER).
A prominent golgi complex develops in the
supranuclear cytoplasm facin the IEE.
in addition to increase expression of messenger
RNA for collagen type 1,
also express for osteocalcin, dentin phosphophoryn
, and high level of alkaline phosphates.
20. As synthesis of type 1 collagen increases
expression of type 3 decreases.
Dental matrix contain type 1 collagen and variety
of glycoproteins and gylcosaminoglycans.
22. The matrix provides a framework for mineralization.
Collagens comprise 90% of the dentin matrix, and are
principally type I
Ty pe I c ol l a ge n is
composed of two identical α1(I) chains and one
α2(I) chain, and a glycine in every third amino acid
position in an individual chain is needed for the
formation of a triple helix structure.
Proα2(I) mRNA has been shown to be expressed
by mature human odontoblasts
23. Ty pe I c ol l a ge n
is synthesised as a larger procollagen, which
contains extensions at both the N- and C-terminal
ends, called the aminoterminal and carboxyterminal
propeptides,
which prevent premature collagen aggregation into
fibrils.
After procollagen secretion from cells, extracellular
modification takes place, and propeptides are
removed by specific proteinases and mature
collagen molecules aggregate into a fibrous matrix
which then serves as a support for mineral
deposition.
24. Ty pe I I I c ol l a ge n,
a homopolymer of three α1(III) chains,
In addition, there is strong evidence that calcified tissues
are also able to express type III collagen,
Type III procollagen has been observed to be transiently
located in human predentin during matrix formation, but not
in mineralized dentin
25. some expression of type V has been observed in the
predentin of mature human teeth but not in dentin .
Instead, type VI was detected both in predentin and dentin
of intact teeth and it has also been found in the teeth of
dentinogenesis imperfecta patients.
26. No n c o l l a g e n o u s
p r ophosphoprotein (DPP; phosphophoryn)
dentin
t e i ns
dentin sialoprotein (DSP)
represent the most abundant dentin-specific acid proteins
in the dental matrix
Odontoblast secret proteoglycans, phosphophoryns and
glycoproteins
27. Predentin protogylcan
functions is to regulate the size and orientation of
collagen fibril and also control the time and site of
mineralisation either by sequestering calcium or by
shielding potential mineral nucleation sites in the
matrix.
Decorin –
a chondroitin-dermatan sulfate proteogylcan
with binding affinity for type 1 collagen..
28. De n t i n
s i a l ophos phopr ot e i n I
s the only protein produced uniquely by odontoblasts, the cells that
produce tooth dentin.
DSPP protein is processed by proteases into several functional fragments;
DSP, DPP and others.
29. These domains play unique biological functions during
dentinogenesis. Preliminary data showed that
1). BMP2 induced DSPP expression.
2). MMP-9 specially catalyzes DSP into the NH2-terminal and
COOH-terminal fragments. The NH2- and COOH-terminal
fragments of DSP show a clear difference in tooth distributions.
3). The NH2-terminal and COOH-terminal domains bind to their
receptors, integrin 26 and CD105, on cellular membrane.
the transcriptional regulation, posttranslational modification and
signal transduction of DSPP are important for controlling the
initiation, rate and extent of dentin biomineralization.
30. Processing of dentin sialophosphoprotein (DSPP) (57). DSPP is the precursor of
dentin phosphoprotein (DPP), a phosphoprotein unique to dentin. DSPP is
processed by proteases (BMP-1, MMP-20, MMP-2) into N-terminal dentin
sialoprotein (DSP), intermediate dentin glycoprotein (DGP) and C-terminal DPP.
DPP is adsorbed on hydroxyapatite crystals and is deposited in dentin matrix.
31. De n t i n
p h o p h o p r o t e i n , or p h o s p
hophor y n,
is important in the regulation of mineralisation of dentin
Phosphophoryn is the most acidic protein ever discovered
and has an isoelectric point of 1.
This extreme acidity is achieved by its amino acid sequence.
Many portions of its chain are repeating -D-S-S- (aspartic
acid-serine-serine) sequences. In protein chemistry, net
acidity equates to negative charge. Being highly
negative, dentin phosphoprotein is able to attract large
amounts ofcalcium
32. Characteristic sequences in dentin phosphoprotein. Most of the DPP molecule is
composed of repetitive sequences, DSS repeats (above). A unit of this sequence
consists of 1 aspartic acid and 2 phosphoserines. The DSS repeat sequences are rich in
negative charges and provide binding sites for many calcium ions (below) and
for hydroxyapatite crystals.
33. SIBLING-family genes. The SIBLING family is a family of acidic glycoproteins
present in bone and dentin. The genes of this family are present as a gene
cluster at the 4q22 site of human chromosome 4. SPARCL1: SPARC-like protein
1, DSPP: dentin sialophosphoprotein, DMP1: dentin matrix protein 1, BSP; bone
sialoprotein, MEPE: matrix extracellular phosphoglycoprotein, OPN:
osteopontin. Two genes of enamel matrix proteins are also present near this
gene cluster; AMBN: ameloblastin, ENAM: enamelin.
34. D e n t i n Ma t r i x P r o t e i
DMP1 appears to belong to the family of dentin
matrix proteins rich in serine and aspartic acid
and has many potential phosphorylation
sites, especially for messenger-independent
kinases of the casein kinase II group.
DMP1 could possibly regulate the expression of
osteocalcin and alkaline phosphatase.
DMP1 is a calcium binding protein as demonstrated by
calcium binding assay
35. that DMP1 can nucleate the formation of hydroxyapatite in
vitro in a multi-step process that begins by DMP1 binding
calcium ions and initiating mineral deposition.
36.
37.
38. P o r c i n e p r e d e n t i n e ma t r i x —
Contains active neutral metalloproteinases (56 and 61 kDa
gelatinases ans 25 kDa proteoglycanase) capble of degrading
proteoglycans at mineralisation site.
Activity is clcium dependent..
Proteoglycans, such a s
d e c o r i n , b i g c l y c a n , f i b r o mo
d u l i n a n d l u m i c a n , which carry
glycosaminoglycan (GAG) carbohydrate side chains within their
structures, comprise another sizeable portion of the
noncollagenous proteins
39. Fi br one c t i n
is re-distributed during odontoblast polarization and
interacts with cell-surface molecules.
A nonintegrin 165-kDa fibronectin-binding
protein, transiently expressed by odontoblasts, is
involved in microfilament reorganization.
40. Growth factors (TGFβ1,2,3/B M P 2,4, a n d
6),
stimulates cytological but not functional differentiation of odontoblasts:
The two events can thus be separated.
Immobilized TGFβ1 (combined with heparin) induced odontoblast
differentiation.
Only immobilized TGFβ1 and 3 or a combination of FGF1 and TGFβ1
stimulated the differentiation of functional odontoblasts over extended
areas and allowed for maintenance of gradients of differentiation.
Presentation of active molecules in vitro appeared to be of major
importance; the BM should fulfill this role in vivo by immobilizing and
spatially presenting TGF(3s).
41. Mi n e r a l i z a t i o n
1.) Matrix vesicles in mantle dentin..
bud from tip of the odontoblastic cytoplasmic process.
It initiate mineralization by concentrating calcium and phosphate ions.
As ion increase hydroxyapatite crystallizes along the inner surface of matix
vessicle surface..
Calcium bonding phospholipids serves as templete for hydroxyapatite
precipitation..
Continue crystal growth ruptures the vesicle and release the hydroxyapatite
crystals into extracellular matrix..
42. 2.) C o l l a g e n p h o s p h o p h o r y n
complexes…
Extracellular Kinases .phosphorylate dentin phosphophoryn which further
linked to collagen fibril,,
This act as nucleators of hydroxyapatite crystal in late mantle dentin and
circumpulpal dentin.
Zone of initial mineralization—
• dot like mineral nuclei are aligned parallel to and superimposed on
collagen fibrils.
• Mineral nuclei positioned over hole region of collagen fibrils, suggesting
that the DPPs are bound to collagen at those sites.
• Dental sialoproteins and proteogylcans act as nucleating agents for
perifibrillar hydroxyapatite crystals.
43. Nucleation of hydroxyapatite by acidic matrix proteins immobilized on insoluble collagen
matrix. Some acidic matrix proteins, e.g. dentin phosphoprotein, have an affinity to
collagen. The surface of the insoluble collagen matrix provides loci to reduce interfacial
energy for nucleation. Calcium ions are bound to the acidic groups of the acidic
proteins, and inorganic phosphates are attracted by the calcium ions. The ionic complex
thus formed may constitute a crystal nucleus.
44. Control of crystal shape by the acidic matrix proteins. Some acidic matrix proteins, e.g.
dentin phosphoprotein, have affinity to a specific face (e.g. the (100) face) of
hydroxyapatite crystals. These proteins are potent inhibitors of crystal growth.
Their specific adsorption results in the inhibition of growth perpendicular to the adsorbed
face. For example, if the (100) face is covered by proteins, growth in the direction of the a-
axis will be inhibited. As a result the crystal will preferentially grow in the direction of the c-
axis.
45. S T R U C T U R E S ..
1.DENTINAL TUBULES..
extend from mantle dentine to predentine.,across the
thickness of circumpulpal dentin..
dentinal tubules contain serum proteins including fibrinogen
,albumin , and immunoglobins.
this proteins are carried into the tubules in dentinal fuild
,where they may be come trapped in the lamina limiitans or
bound to the mineral phase of dentin.
47. F O R MA T I O N O F
I NT ERT UBUL AR
1. Greatest bulk of mineralised circumpulal dentin.
2. it is formed by the mineralisation of predentin.
3. Matrix is rich in type 1 collagen fibrils
48. PERI T UBUL AR DENT I N.
These inner organic lining is described as a thin organic lining high in GAG and
relatively free in collagen fibrils .
Bone sialoprotein and osteonectin have been localized in peritubular dentin.
Because of its small crystallites and non collagenous nature of its organic
material , it is more susceptible to demineralization and degradation during
the caries process.
.
49. F o r ms o f
de nt i n
•Primary dentin, with straight
tubules, is laid down before completion
of the apical foramen.
•Regular secondary dentin is
characterized by a slower rate of
deposition and an abrupt change in the
direction of the dentinal tubules.
•Tertiary or irregular secondary (also
called irritation, reparative or reactive)
dentin is laid down in response to an
irritation or damage to the overlying
dentin and/or enamel.
•This dentin has irregularly arranged A, Primary dentin;
B, Secondary (regular) dentin;
and few dentinal tubules. With aging or
C, Reactive dentin
severe damage, tertiary dentin can
totally obliterate the pulp cavity.
50. Interglobulardentin in globular
layer -ground section
•Between the mantle and
circumpulpallayers is a layer of dentin
in which the calcified globules do not
fuse evenly.
•This is called the globular layer.
•In a ground section of dentin, the
less-calcified areas of dentin appear
as irregularly shaped crescents called
interglobulardentin.
51. AGE & F u n c t i o n a l
Ch a n g e s
The main changes in dentin associated with aging are
1. Increase in peritubular dentin.
2. Increase in Dentinal sclerosis.
3. Increase in the number of dead tracts.
4. The dentinal permeability decreases with advancing
age.
5. The color of dentin becoming darker with age.
6. Hardness of dentin increases with age, primarily due
to increases in mineral content.
52. 2. R e p a r a t i v e de nt i n
If the provoking stimulus caused the destruction of the original
odontoblasts, the new, less tubular, more irregular dentin formed by newly
differentiated odontoblast like cells is called Reparative dentin.
In such dentin the tubules are usually not continuous with those of
secondary dentin.
Unlike primary or secondary dentin, which forms along the entire pulp-
dentin border, tertiary dentin is produced only by cells directly affected by
the stimulus.
The quality (or architecture) and the quantity or degree of tertiary dentin
produced are related to the cellular response initiated, which depends on
the intensity or duration of the stimulus.
Tertiary dentin may have regular tubules continuous with those of
secondary dentin, tubules sparse in number and irregularly arranged or no
tubules at all.
53. The cells forming territory dentin either line its surface or are included in the dentin.
In the latter case, this dentin is as referred to as Osteodentin.
Various factors associated with cavity preparation and
restoration can influence the tertiary dentinogenic response:
The method of cavity preparation, the dimensions of the cavity, the residual dentin
thickness (RDT) of the cavity, etching of the cavity, and the nature of the dental
materials used and the method of their application for the restoration.
54. De a d t r a c t s
In dried ground sections of normal dentin the odontoblast
processes disintegrate, and the empty tubules are filled with
air.
These are called Dead tracts.
They appear black in transmitted light and white in reflected
light.
Loss of odontoblast processes may also occur in teeth
containing dental pulp as a result of
caries, attrition, abrasion, cavity preparation, or erosion.
Their degeneration is often observed in the area of narrow
pulpal horns because of crowding of odontoblasts.
Dentin areas characterized by degenerated odontoblast
processes give rise to dead tracts.
55. These areas demonstrate decreased sensitivity and
appear to a greater extent in older teeth.
Dead tracts are probably the initial step in the
formation of sclerotic dentin.
56. or , Tr a ns pa r e nt
de nt i n:
Sclerotic dentin results from aging or mild irritation such as
slowly advancing caries and causes a change in the
composition of the primary dentin.
The peritubular dentin becomes wider, gradually filling the
tubules with calcified material, progressing pulpally from the
DEJ.
These areas are harder, dense, less sensitive and more
protective of the pulp against subsequent irritations.
Sclerosis resulting from aging is physiologic dentin sclerosis.
Sclerosis resulting from a mild irritation is Reactive dentin
sclerosis.
57. It appears transparent or light in transmitted light
and dark in reflected light.
The amount of sclerotic dentin increased with age and
is most common in the apical third of the root and in
the crown midway between the DEJ and the surface
of the pulp.
Because sclerosis reduces the permeability of
dentin, it may help to prolong pulp vitality.
Eburnated dentin: Refers to the outward (exposed)
portion of reactive sclerotic dentin, where slow caries
has destroyed formerly overlying tooth
structure, leaving a hard, darkened, cleanable
58.
59. 1. Hardness of sclerotic dentin is approximately 30% higher
than normal dentin with equal depth, showing this to be a
more mineralized tissue;
2. The thickness of the hybrid layer formed on sclerotic dentin is
less than normal dentin, thus, showing this tissue to be more
resistant to demineralization caused by acid etching;
3. Bond strength to sclerotic dentin is not as high as normal
dentin;
4. At the time of acid etching the sclerotic occlusal
dentin, doubling the time of application of 35% phosphoric
acid contributes to obtaining a bond strength similar to normal
dentin; and
5. For normal occlusal dentin, no difference exists in bond
strength when 35% phosphoric acid etchant is applied
following the manufacturer’s suggested time (15 seconds), or
when the time is extended to 30 seconds.
Editor's Notes
Differentiation of odontoblasts is mediated by expression of signaling molecules and growth factors in the inner dental epithelial cells
It is rich in endoplasmic reticulum and Golgi apparatus, especially during primary dentin formation, to give it a high secretory capacity (firstly collagenous matrix to form predentine, then mineral to form the complete dentine).
Calcium channels are localized to apical pole of preodontoblast.
Terminal web divide it into 2 part..cell body and odontoblastic process……this zone of attachment prevents the entrapment of odontoblast in the prsdenine matrix and ensures that the developing surface of the dentin remains relatively flat..
Golgi complex is subdivided into cis-golginetwork,golgi stacks, trans golgi network..cisgolgi acts as quality control—prevent the transfer of defective proteins.Retrograde traffic also return membranes lipids
GNRP – GUANINE NUCLEOTIDE RELEASING PROTEIN GTP-- GUANOSINE TRIPHOSPHATE..ARF– ADENOSINE DIPHOSPHATE RIBOSYLATION FACTORGDP—GUANOSINE DIPHOSPHATE BOUND STATE.SNAREs---N-ethylmaleimide-sensitive fusion attachment protein receptors
V-snare binding to appropriate t-snare..Arf-gtp is hydrolysed to arf- gdp …and dissociates from vessicles membrane..coatomer is also released..Attachment of v-snare to t-snare is monitered and stabilized by Rab-GTP molecule present in donor vesicle membraneNSF-P ---- N-ethylmaleimide sensitive fusion protein SNAPs---- soluble NSF attachment protiens