1. NETs are extracellular webs composed of DNA and proteins that are released by neutrophils to trap and kill microbes.
2. NET formation, called NETosis, can occur through either a lytic process involving cell death or a non-lytic process where cells remain alive.
3. NETs can have both beneficial effects by killing microbes but also pathogenic effects by damaging tissues, promoting thrombosis, and providing autoantigens that stimulate autoimmunity. Many diseases like lupus, rheumatoid arthritis, and vasculitis involve abnormal NET formation or responses.
The angiogenesis process, the factors regulating it, different assays for it, a little about tumour angiogenesis, the drugs and new therapeutic approaches towards inhibiting or augmenting the process.
The angiogenesis process, the factors regulating it, different assays for it, a little about tumour angiogenesis, the drugs and new therapeutic approaches towards inhibiting or augmenting the process.
various cutaneous lymphomas though having low incidence but need to be diagnosed accurately. they can be mimiced by many non neoplastic conditions of skin. so discussing both T and B cell lymphomas
Localised protective response elicited by injury or destruction of tissues which serves to destroy , dilute or wall off (sequester) both injurious agent and the injured tissues (Dorlands medical dictionary). Cardinal signs of inflammation
Celsus 1st century AD
Rubor – redness
Tumor -swelling
Calor -heat
Dolor -pain
Virchow
“function laesa”- loss of function
various cutaneous lymphomas though having low incidence but need to be diagnosed accurately. they can be mimiced by many non neoplastic conditions of skin. so discussing both T and B cell lymphomas
Localised protective response elicited by injury or destruction of tissues which serves to destroy , dilute or wall off (sequester) both injurious agent and the injured tissues (Dorlands medical dictionary). Cardinal signs of inflammation
Celsus 1st century AD
Rubor – redness
Tumor -swelling
Calor -heat
Dolor -pain
Virchow
“function laesa”- loss of function
Rationale of endodontics / /certified fixed orthodontic courses by Indian den...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.
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.
MANAGEMENT OF ATRIOVENTRICULAR CONDUCTION BLOCK.pdfJim Jacob Roy
Cardiac conduction defects can occur due to various causes.
Atrioventricular conduction blocks ( AV blocks ) are classified into 3 types.
This document describes the acute management of AV block.
These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
Pulmonary Thromboembolism - etilogy, types, medical- Surgical and nursing man...VarunMahajani
Disruption of blood supply to lung alveoli due to blockage of one or more pulmonary blood vessels is called as Pulmonary thromboembolism. In this presentation we will discuss its causes, types and its management in depth.
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
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.
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.
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
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.
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
2. Points of discussion
• Definition of NET & NETosis
• Brief history
• Types
• Mechanism of NET formation
• Action of NETs
• NETs and autoimmunity
• Therapy related to NET
• COVID & NETosis
3. NET – Definition
• NETs are large, extracellular, web-like structures composed of
cytosolic and granule proteins that are assembled on a scaffold
of decondensed chromatin
• Majority of DNA from nucleus , also from mitochondria
• NETs trap, neutralize and kill bacteria, fungi, viruses and
parasites and are thought to prevent bacterial and fungal
dissemination
5. History
• In 2004 , Brinkmann et al described NET
• Stimulation with IL8, PMA , LPS & visualization with EM and IF
- NETs were observed
• Under EM - NETs were composed of linear elements about 15–17
(nm) in diameter and are studded with globules
• The backbone of these NETs was composed of DNA and histones as
demonstrated by IF
8. NETOSIS -definition
• NET release occurs primarily through a cell death process
termed NETosis
• 2007 - it is declared as unique cell death pathway of
neutrophil
• During NETosis, neutrophils release NETs, which can capture
and kill bacteria and other pathogens to prevent them from
spreading.
12. lytic NETosis – suicidal
• Slow cell death
• Neutrophils arrest their actin dynamics and depolarize
• Nuclear envelope disassembles
• Delobulation of nuclei
• Nuclear chromatin decondenses into the cytoplasm mixing with
cytoplasmic and granule components
• Plasma membrane then permeabilizes
• NETs expand into the extracellular space 3–8 hours after neutrophil
activation
14. Non-lytic NETosis – vital
• It leads to the rapid release of NETs within minutes of
exposure to Staphylococcus aureus via the secretion of
chromatin and granule contents
• No cell death – rapid response
• Seen in small fraction of neutrophils during systemic
S. aureus infection
• Generates NETs and anucleated cytoplasts that crawl and
phagocytose bacteria
19. Basic steps
1. Activation of ROS by NOX or NOX independent pathway
2. Release of NE and translocation to nucleus
3. MPO- NE mediated chromatin decondensation
4. Hyper-citrullination of chromatin
5. Nuclear and cell membrane permeabilization
6. Release of NET
20.
21. ROS activation
• ROS generated by NADPH oxidase stimulate MPO to trigger the
activation and translocation of NE to the nucleus
• ROS-inducing receptors & kinases - MEK (MAPK/ERK kinase),
ERK, IRAK, PKC, PI3K and AKT – activate ROS in response to
PMA, microorganisms, parasites and immobilized immune
complexes
• Requirement for PI3K in NETosis has also implicated a role for
autophagy
22. MPO- NE pathway
• NE binds to F-actin filaments in the cytoplasm and degrade
them & enter the nucleus
• NE proteolytically processes histones to disrupt chromatin
packaging
• MPO binds chromatin and synergizes with NE in
decondensing chromatin independently of its enzymatic
activity
• MPO–NE pathway is induced by many NET stimuli, such as
fungi and crystals
23. Other biochemical events
• In resting neutrophils - fraction of MPO is bound to NE as
part of a complex called the azurosome
• H2O2 - selectively releases NE into the cytosol in an MPO-
dependent manner at physiological condition
• Chlorinated polyamines - crosslink NET proteins, increasing
NET stability and integrity and potentiating the capture of
microorganisms
24. NOX – independent pathway
• Immune complexes, ionomycin and nicotine, trigger NETosis
independently of NOX , relying instead on mitochondrial
ROS
• Non-lytic NETosis is also thought to occur independently of
ROS
• Glycans in saliva induce NETs via an unknown mechanism
25. Chromatin decondensation
• Histone deamination or hyper citrullination
• Driven by peptidylarginine deiminase 4 (PAD4)
• H202 - is sufficient to activate PAD4 which requires calcium
and is activated by PKC
• PAD4 inhibition blocks NET release in mouse models of
sepsis and cancer
• Histone citrullination and MPO-NE activity lead to
chromatin decondensation
26. Membrane permeabilization
• Plasma membrane permeabilization occurs in a programmed
manner & not as a consequence of physical disruption by the
expanding chromatin
• Monosodium urate (MSU) crystals promote necroptosis with
receptor-interacting serine/threonine-protein kinase 1 (RIPK1)
and RIPK3,
27.
28.
29. Regulation of NETosis
• Larger microorganisms- NET
• Larger particle size -NET
• Small virulent microorganisms that interfere with phagosomal
killing
• Large aggregates or abscess – favors NET
• Microbial interference with phagosome maturation ( N .
gonorrhea )
• Presence of motile flagella ( pseudomonas )
• Expression of enzyme ( invasin in yersinia )
• Lacking phagocyte promoting protease – cause NET
33. Microbiocidal action
• Kill or suppress bacterial ,fungal, viral proliferation
• Underlying mechanisms poorly understood.
• Histones, defensins & cathelicidins - potent antimicrobials
in NETs
• NETosis is also likely to be the major route for the release of
calprotectin
• Physical sequestration of microorganisms by NETs is also
thought to prevent systemic dissemination
38. NETs promote vaso-occlusion
• Provide a scaffold that promotes DVT
• Hypoxia-induced release of VWF & P-selectin from the endothelium
initiate NET formation
• Thromboxane A2 induces endothelial cell expression of ICAM1 to
strengthen neutrophil interactions
• Platelet- derived high mobility group protein B1 (HMGB1), ROS
and integrins trigger NETosis
39. Vaso-occlusion
• NETs recruit Factor XIIa
• Mobilizes endothelial cell granules (Weibel–Palade bodies)
that contain VWF, P-selectin , Factor XIIa
• Extracellular NET histones bind VWF and fibrin to recruit
platelets and red blood cells
• NET-bound NE cleaves tissue factor pathway inhibitor (TFPI)
and proteolytically activates platelet receptors to increase
platelet accumulation
41. Other vascular events
• NETs form in response to the build-up of bicarbonate salts and
occlude pancreatic ducts to drive pancreatitis
• NETosis in response to free haem may contribute to vaso-
occlusion in sickle cell disease
42. NETs modulate sterile inflammation
• NETs regulate inflammatory cytokines directly or indirectly by
modulating immune cells
• Early inflammatory stages induce NETs by IL-6 & pro-IL-
1β in macrophages via TLR2 & 4
• Th 17 cell increased
• Increased myeloid cell recruitment to site of inflamed lesions
like atherosclerotic plaque
44. Sterile inflammation ( contd )
• Mouse model of ischaemia– reperfusion injury - NETs amplify
inflammation and liver damage
• NETs and neutrophil-derived IL-17 – role in Alzheimer
disease
46. • NETs promote inflammation and tissue destruction - delay
wound healing in diabetes
• Glucose is required for NETosis & neutrophils from patients
with diabetes release NETs more readily
• NETs - detected in adipose tissues of obese mice
Sterile inflammation ( contd )
48. Anti-inflammatory response
• NETs were suggested to have an anti-inflammatory
role in mouse models of gout induced by MSU
crystals
• It is possible that NETs initiate inflammation and, as
they build up over time, potentiate its resolution.
51. NETS in autoimmunity
• NETs - source of self-antigen in autoimmune diseases
• Autoantibodies against neutrophil- derived proteins
• NET - first reported in kidney biopsy in ANCA-
associated vasculitis - antibodies against NET
components , MPO & proteinase 3
• Nuclear material released from NETs more immunogenic
• Oxidised DNA in NET – promote IFN 1 signalling
52.
53. SLE
• NETs activate plasmacytoid dendritic cells (pDCs) via TLR9 and
TLR7 signalling & promote type I IFN expression
• Mitochondrial ROS oxidize NET DNA to increase its ability to
activate the stimulator of interferon genes (STING) pathway and
trigger IFN production by pDCs
• small population of circulating low-density granulocytes (LDGs)
releases NETs spontaneously
57. Rheumatoid arthritis
• Enhanced NETosis - detected in circulating & synovial-fluid
neutrophils, synovial tissue, rheumatoid nodules, skin of
affected patients
• NETs are a source of extracellular citrullinated autoantigens
• Release of active PAD isoforms through NETosis, citrullinate
extracellular histones and fibrinogen in RA
• It stimulate production of proinflammatory cytokines,
chemokines & adhesion molecules in synovial fibroblasts
59. ANCA associated vasculitis
• Antibodies to MPO & PR3 – pathogenic
• They activate neutrophils primed by a proinflammatory stimuli,
leading to respiratory burst
• Enhanced NET formation in vitro
• Lvels of NET remnants (MPO–DNA complexes), and
neutrophil granular proteins, such as calprotectin , were
increased in sera of AAV
• NET formation is involved in vascular damage and immune
system activation in AAV
60. AAV – NET
• ANCA induced NETs generated by C5a-primed neutrophils cause
enhanced thrombosis & inflammation in AAV by promoting the
expression of tissue factor
• NETs can also present PR3 and MPO to dendritic cells
• NETs - important sources of modified autoantigens in the kidney.
• In necrotizing crescentic glomerulonephritis, neutrophil serine
proteases like cathepsin G, neutrophil elastase and PR3 promoted
IL-1β generation and kidney injury
62. APS
• NETs - important activators of the coagulation cascade &
integral components of arterial and venous thrombin
• Serum of APS displays - decreased ability to degrade NETs
• Elevated levels of both cell-free DNA and NET remnants
• aPLs promote the release of NETs in a ROS and TLR4-
dependent manner
• A LDG population has also been described in primary AP
68. Therapeutic strategy in autoimmunity
• Inhibition of ROS production by targeting NADPH or
mitochondria
• ROS scavenger - N-acetyl cysteine (NAC) reduce NET release
• MPO inhibitors - 4-aminobenzoic acid hydrazide or PF-1355-
reduce NETosis, neutrophil recruitment and levels of circulating
cytokines
• TLR inhibitor - TAK-242
• PAD inhibitors - Cl-amidine , BB-Cl-amidine
69. • Targeting B cells & plasma cells - reduction of autoantibody-
induced NET formation
• Inhibitors of calcineurin or GPCR phospholipase C
( staurosporine ) - suppress or modulate NETosis
• DNase 1 - enhance their clearance
• Targeting CXCL5 - decrease TH17-mediated autoimmunity -
crescentic glomerulonephritis
• Inhibition of TNF and IL-17 decreases NET in RA
• Anti-C5 mAb therapy
Therapeutic strategy
73. A Role for NETosis in COVID-19 Infection?
• Cytokine storm seen with COVID-19 elaborates role of NET
• NETs can induce macrophages to secrete IL1β & form a loop
between macrophages and neutrophils, leading to progressive
inflammatory damage.
• Virus -induced NETs can circulate in an uncontrolled way, leading
to an extreme systemic response of the body like ARDS .
• NETs can be detected in tissues by immunohistochemistry & in
blood by sandwich ELISA
74. NET – lung damage – therapeutic
aspect in COVID 19
75. Take home message
1. NETosis- programmed cell death , unique in neutrophil
2. NETs are extracellular web like structure on scaffold of decondensed
chromatin with granules
3. Either suicidal causing cell death or vital where no lysis happens
4. Mecahnism - activation of ROS , MPO-NE pathway , chromatin
decondensation and increased permeability
5. It has multiple actions – microbiocidal , damage host tissue , sterile
inflammation ( atherosclerosis , diabetes ),vaso –occlusion(DVT) and
autoimmunity, malignancy
6. SLE , AAV ,gout ,RA , cresecentic GN – NET has important role
7. Therapeutic target of NETs are emerging
8. COVID 19 – NET – association is highly possible
76. References
1. Papayannopoulos, V. Neutrophil extracellular traps in immunity and disease.
Nat Rev Immunol 18, 134–147 (2018)
2. Gupta, S., Kaplan, M. The role of neutrophils and NETosis in autoimmune
and renal diseases. Nat Rev Nephrol 12, 402–413 (2016).
3. De Bont, C.M., Boelens, W.C. & Pruijn, G.J.M. NETosis, complement, and
coagulation: a triangular relationship. Cell Mol Immunol 16, 19–27 (2019).
4. Miguel Antonio Mesa1 and Gloria Vasque . NETosis . Autoimmune Diseases
/ 2013
5. Elsherif L, Sciaky N, Metts CA, et al. Machine Learning to Quantitate
Neutrophil NETosis. Sci Rep. 2019;9(1):16891.
77. 6.. Bryan G. Yipp, Paul Kubes; NETosis: how vital is it?. Blood 2013; 122
(16): 2784–2794
7. Boilard,E., Fortin, P. Mitochondria drive NETosis and inflammation in
SLE. Nat Rev Rheumatol 12, 195–196 (2016
8. Xavier Bosch. Systemic Lupus Erythematosus and the Neutrophil. N Engl
J Med 2011; 365:758-760
9. Nicoletta Sorvillo. Circulation Research. Extracellular DNA NET-Works
With Dire Consequences for Health, Volume: 125, Issue: 4,
References