Fiber characterization involves testing optical fibers to ensure they are suitable for the intended transmission system. Key tests include inspecting connectors for contamination, measuring insertion loss, return loss, and dispersion. Optical time domain reflectometers locate events along the fiber such as splices, macrobends, and breaks. High contamination can significantly increase loss and reflections compared to clean connections. Precise characterization is needed to validate fiber plant performance.
Optical fiber communication uses glass or plastic fibers to transmit light signals for telecommunication. Light from a laser or LED is transmitted through the fiber's core using total internal reflection. Optical fibers have advantages over copper cables including higher bandwidth, less signal degradation, lighter weight, and immunity to electromagnetic interference. Fiber systems use single-mode or multi-mode fibers depending on the transmission distance and bandwidth needs.
Optical fiber is a flexible transparent fiber made of glass or plastic that transmits light and is used for fiber-optic communication. It consists of a core that light travels through, surrounded by cladding and a protective buffer coating. Light is reflected down the fiber by the coating and emerges from the other end with little loss. Optical fiber has advantages over copper wire like higher bandwidth, less signal degradation over longer distances, and non-flammability. Common applications include use by cable companies, utilities, LANs, and broadcasting.
The document discusses various topics related to optical fibers including:
1. Attenuation in optical fibers is caused by material or impurity losses, scattering losses, absorption losses, and bending losses.
2. Different types of attenuation in fibers include intrinsic losses, Fresnel losses, and ray scattering losses. Absorption losses occur due to ion impurities and include intrinsic and extrinsic absorption.
3. Dispersion in fibers includes intermodal and intramodal dispersion. Intermodal dispersion is caused by different propagation delays between modes, while intramodal dispersion includes material and waveguide dispersion.
This document discusses optical fiber communication, including its evolution, structure, working principle, classification, advantages and applications. Optical fiber communication transmits light pulses through fiber to exchange information over long distances. Historically it was first proposed in 1880 and lasers were introduced as light sources in 1960. Optical fibers are classified as single mode or multi-mode depending on the number of modes light can propagate through. They work on the principle of total internal reflection. Optical fiber communication is used for telecommunication networks, cable TV, and military applications due to its high bandwidth, security and flexibility.
Fiber optics measurement Technique by mitesh kumarMitesh Kumar
The document discusses fiber optic measurement techniques, including using an optical time domain reflectometer (OTDR) to measure fiber attenuation and locate faults by launching light pulses and measuring backscatter, as well as using a power meter to directly measure signal loss in a link by comparing readings with and without the device under test. Proper procedures are outlined for ensuring accurate OTDR and power meter readings, and other fiber optic measurement tools like those made by EXFO are presented for evaluating chromatic dispersion and polarization mode dispersion.
This document discusses optical fiber communication and ray optics models. It begins by introducing different types of rays in optical fibers including meridional, skew, guided, and leaky rays. It then covers ray theory transmission and the ray model. Key aspects of meridional, skew, and leaky rays are defined. The document also discusses step index and graded index optical fibers as well as their characteristics and applications.
Fiber characterization involves testing optical fibers to ensure they are suitable for the intended transmission system. Key tests include inspecting connectors for contamination, measuring insertion loss, return loss, and dispersion. Optical time domain reflectometers locate events along the fiber such as splices, macrobends, and breaks. High contamination can significantly increase loss and reflections compared to clean connections. Precise characterization is needed to validate fiber plant performance.
Optical fiber communication uses glass or plastic fibers to transmit light signals for telecommunication. Light from a laser or LED is transmitted through the fiber's core using total internal reflection. Optical fibers have advantages over copper cables including higher bandwidth, less signal degradation, lighter weight, and immunity to electromagnetic interference. Fiber systems use single-mode or multi-mode fibers depending on the transmission distance and bandwidth needs.
Optical fiber is a flexible transparent fiber made of glass or plastic that transmits light and is used for fiber-optic communication. It consists of a core that light travels through, surrounded by cladding and a protective buffer coating. Light is reflected down the fiber by the coating and emerges from the other end with little loss. Optical fiber has advantages over copper wire like higher bandwidth, less signal degradation over longer distances, and non-flammability. Common applications include use by cable companies, utilities, LANs, and broadcasting.
The document discusses various topics related to optical fibers including:
1. Attenuation in optical fibers is caused by material or impurity losses, scattering losses, absorption losses, and bending losses.
2. Different types of attenuation in fibers include intrinsic losses, Fresnel losses, and ray scattering losses. Absorption losses occur due to ion impurities and include intrinsic and extrinsic absorption.
3. Dispersion in fibers includes intermodal and intramodal dispersion. Intermodal dispersion is caused by different propagation delays between modes, while intramodal dispersion includes material and waveguide dispersion.
This document discusses optical fiber communication, including its evolution, structure, working principle, classification, advantages and applications. Optical fiber communication transmits light pulses through fiber to exchange information over long distances. Historically it was first proposed in 1880 and lasers were introduced as light sources in 1960. Optical fibers are classified as single mode or multi-mode depending on the number of modes light can propagate through. They work on the principle of total internal reflection. Optical fiber communication is used for telecommunication networks, cable TV, and military applications due to its high bandwidth, security and flexibility.
Fiber optics measurement Technique by mitesh kumarMitesh Kumar
The document discusses fiber optic measurement techniques, including using an optical time domain reflectometer (OTDR) to measure fiber attenuation and locate faults by launching light pulses and measuring backscatter, as well as using a power meter to directly measure signal loss in a link by comparing readings with and without the device under test. Proper procedures are outlined for ensuring accurate OTDR and power meter readings, and other fiber optic measurement tools like those made by EXFO are presented for evaluating chromatic dispersion and polarization mode dispersion.
This document discusses optical fiber communication and ray optics models. It begins by introducing different types of rays in optical fibers including meridional, skew, guided, and leaky rays. It then covers ray theory transmission and the ray model. Key aspects of meridional, skew, and leaky rays are defined. The document also discusses step index and graded index optical fibers as well as their characteristics and applications.
Nerves conduction study, Axonal loss vs DemyelinationAhmad Shahir
This document summarizes the key differences between axonal loss and demyelination lesions as assessed by nerve conduction studies. Axonal loss lesions typically show decreased amplitudes with normal or slightly slowed conduction velocities and distal latencies. Demyelination lesions are characterized by markedly slowed conduction velocities below 75% of the lower limit of normal or prolonged distal latencies over 130% of the upper limit, indicating primary demyelination. The document discusses various patterns that can be seen on nerve conduction studies for both types of lesions and their clinical implications.
1) Recent advances in understanding the pathophysiology of motor neuron disease include insights into excitotoxicity, oxidative stress, mitochondrial defects, impaired axonal transport, protein aggregation, inflammation, and neurotrophic factor deficits.
2) Riluzole remains the only FDA-approved drug shown to modestly prolong survival for patients with ALS, though Edaravone may also provide benefits for certain subgroups. Experimental therapies targeting genes, antioxidants, neurotrophic factors, and other mechanisms are under investigation.
3) Making an accurate diagnosis involves evaluating the patient's history, physical exam, electrodiagnostic testing, imaging, and sometimes genetic or biomarker analysis to differentiate ALS from other conditions.
Nerve conduction studies and electromyography are used to diagnose disorders of the peripheral nervous system including motor and sensory neurons, nerve roots, plexuses, peripheral nerves, neuromuscular junctions, and muscles. The document provides details on the anatomy and physiology relevant to nerve conduction studies and electromyography. It then describes the fundamentals and technical aspects of performing nerve conduction studies to evaluate motor, sensory, and mixed nerves. Common conduction study patterns are presented to characterize axonal loss, demyelination, myopathies, and neuromuscular junction disorders. Late responses including F-waves, H-reflexes, and axon reflexes are also summarized.
EEG measures the electrical activity of the brain through electrodes placed on the scalp. It can detect different wave patterns associated with different brain states. Evoked potentials involve stimulating a sensory pathway and measuring the electrical response along the pathway. This allows localization of lesions. Somatosensory evoked potentials involve stimulating a peripheral nerve like the median nerve and measuring the response along the pathway to detect spinal cord or brain injuries. Auditory evoked potentials involve measuring the brainstem response to a click stimulus to detect acoustic neuromas or other posterior fossa lesions. Both evoked potentials and EMG monitoring are used during surgery to detect injuries.
The following ppt gives overview about Optical Communication and the underlying principle with the general overview of all the contents for optical communication
This document discusses junctionless transistors as an alternative to traditional transistors. Junctionless transistors have no p-n junctions and instead use uniformly doped semiconductor material. They offer advantages like simpler fabrication without implantation or annealing steps, reduced short channel effects, higher carrier mobility, and lower leakage current. However, they can have greater threshold voltage variability than conventional transistors. The document provides details on the structure and operation of junctionless transistors, comparing them to traditional transistors and discussing their potential to enable further device miniaturization.
This document provides information about optical fiber communication systems. It discusses the key components of these systems including optical sources, modulators, optical fibers as the transmission medium, and photodetectors. It also outlines the historical development of fiber optic technology from early experiments in the late 19th century to current commercial systems. The advantages of optical fiber communication over electrical transmission are highlighted such as higher bandwidth, longer transmission distances, and immunity to electromagnetic interference.
There are two main types of optical fiber signal loss: scattering and absorption. Scattering losses include Rayleigh scattering caused by molecular irregularities and Mie scattering caused by larger defects. Absorption losses are caused by intrinsic material properties like ultraviolet and infrared absorption in silica glass, as well as extrinsic impurities introduced during manufacturing. Proper fiber design and high material purity can minimize these signal losses to enable effective optical fiber communication.
Minimally invasive spine surgeries (MISS) aim to minimize soft tissue damage during spinal procedures. MISS techniques using tubular retractors or endoscopes have been applied to procedures like discectomy, decompression, and fusion. MISS may provide benefits over open techniques like less blood loss, shorter hospital stays, and faster recovery. However, MISS also has disadvantages like a steep learning curve, dependence on technology, and higher initial costs. The applications of MISS continue to expand but further research is still needed to fully understand its advantages and disadvantages.
A Comparative Study of the Clinical and Functional Outcome Anterior Cruciate ...TheRightDoctors
A Comparative Study of the Clinical and Functional Outcome Anterior Cruciate Ligament Reconstruction Using Transportal and Transtibial Approach for Femoral Tunnel Drilling-Dr. Adarsh Reddy
1) What is Fiber Optics?
2) Structure of Fiber Optics.
3) Modes of Fiber Optics.
4) How It Is made.
5) Communication System.
6) Evolution of Fiber Optics.
7) Advantages/ Disadvantages.
8) Applications of Fiber Optics.
9) Conclusion.
Dr. Sunil Kumar Sharma's document discusses various functional neuroimaging modalities including fMRI, PET, and SPECT. It provides details on how each modality works, its advantages and disadvantages, and examples of its applications in mapping brain functions and depicting disease-related changes. Specific conditions discussed in relation to imaging findings include dementia, Parkinsonism, brain tumors, and epilepsy.
This presentation describes the common conditions, anatomy and the ideal ways to do and perform nerve conduction studies in lower limbs. It is nicely depicted with self explanatory pictures.
1. The document discusses optical fibers, specifically step index fibers. It describes step index fibers as having a core with a constant refractive index n1 surrounded by a cladding with a slightly lower refractive index n2.
2. It discusses several factors that determine the number of propagating modes in a step index fiber, including the V-number which is a function of the core radius, wavelengths, and refractive index differences. Fibers with V<2.405 support only one mode.
3. Dispersion effects in step index fibers include intermodal dispersion from different propagation speeds of fiber modes, and material dispersion from the wavelength dependence of the core refractive index.
Cortical dysplasia is a malformation of cortical development caused by abnormal neuronal migration or organization during brain development. It can cause intractable epilepsy and neurodevelopmental disorders like autism. The lecture discusses normal brain development and corticogenesis. It then covers specific malformations including focal cortical dysplasia, describing their histopathology and clinical correlates. Recent research suggests focal disruptions of cortical layering found in children with autism may represent early cortical dysplasia, providing insight into a potential cause of autism.
This document discusses photonic crystal fibers (PCFs). PCFs are composed of nanostructures that affect photon propagation through periodic refractive indices, similar to how semiconductor crystals affect electron motion. PCFs can guide light through two mechanisms: index guiding and photonic bandgap guiding. They have properties like endless single mode operation, large mode areas, and tunable dispersion. Special PCFs include double core fibers, highly birefringent fibers, and hollow core bandgap fibers. PCFs offer advantages over standard fibers like flexibility in core size and wavelengths used. Challenges include difficult fabrication and limited operating frequencies.
Optical fiber communication-Presented by Kiran DevkotaSujit Jha
This document discusses optical fiber communication and fiber optic cables. It covers the following key points:
- Fiber optics uses light to transmit information through glass or plastic strands. Unlike copper transmission, it is not electrical in nature.
- The basic components of a fiber optic cable are the core that carries light, cladding surrounding the core, a coating for protection, and a cable jacket.
- Fiber materials include silica glass, plastic, and plastic-clad fibers. Single-mode fiber has a small core for long distances, while multimode fiber has a larger core for short distances.
- Fiber optic communication has advantages like large bandwidth, small size, electrical isolation, and low
This document provides an overview of peripheral neuropathy, including:
1. It describes the anatomy of peripheral nerves and different types of peripheral neuropathies such as mononeuropathy, mononeuropathy multiplex, polyneuropathy, polyradiculopathy, and plexopathy.
2. It outlines the various clinical presentations of peripheral neuropathy including sensory, motor, and autonomic symptoms as well as patterns of nerve fiber involvement.
3. It discusses the etiology, clinical course, investigations and management of different peripheral neuropathies.
Nerves conduction study, Axonal loss vs DemyelinationAhmad Shahir
This document summarizes the key differences between axonal loss and demyelination lesions as assessed by nerve conduction studies. Axonal loss lesions typically show decreased amplitudes with normal or slightly slowed conduction velocities and distal latencies. Demyelination lesions are characterized by markedly slowed conduction velocities below 75% of the lower limit of normal or prolonged distal latencies over 130% of the upper limit, indicating primary demyelination. The document discusses various patterns that can be seen on nerve conduction studies for both types of lesions and their clinical implications.
1) Recent advances in understanding the pathophysiology of motor neuron disease include insights into excitotoxicity, oxidative stress, mitochondrial defects, impaired axonal transport, protein aggregation, inflammation, and neurotrophic factor deficits.
2) Riluzole remains the only FDA-approved drug shown to modestly prolong survival for patients with ALS, though Edaravone may also provide benefits for certain subgroups. Experimental therapies targeting genes, antioxidants, neurotrophic factors, and other mechanisms are under investigation.
3) Making an accurate diagnosis involves evaluating the patient's history, physical exam, electrodiagnostic testing, imaging, and sometimes genetic or biomarker analysis to differentiate ALS from other conditions.
Nerve conduction studies and electromyography are used to diagnose disorders of the peripheral nervous system including motor and sensory neurons, nerve roots, plexuses, peripheral nerves, neuromuscular junctions, and muscles. The document provides details on the anatomy and physiology relevant to nerve conduction studies and electromyography. It then describes the fundamentals and technical aspects of performing nerve conduction studies to evaluate motor, sensory, and mixed nerves. Common conduction study patterns are presented to characterize axonal loss, demyelination, myopathies, and neuromuscular junction disorders. Late responses including F-waves, H-reflexes, and axon reflexes are also summarized.
EEG measures the electrical activity of the brain through electrodes placed on the scalp. It can detect different wave patterns associated with different brain states. Evoked potentials involve stimulating a sensory pathway and measuring the electrical response along the pathway. This allows localization of lesions. Somatosensory evoked potentials involve stimulating a peripheral nerve like the median nerve and measuring the response along the pathway to detect spinal cord or brain injuries. Auditory evoked potentials involve measuring the brainstem response to a click stimulus to detect acoustic neuromas or other posterior fossa lesions. Both evoked potentials and EMG monitoring are used during surgery to detect injuries.
The following ppt gives overview about Optical Communication and the underlying principle with the general overview of all the contents for optical communication
This document discusses junctionless transistors as an alternative to traditional transistors. Junctionless transistors have no p-n junctions and instead use uniformly doped semiconductor material. They offer advantages like simpler fabrication without implantation or annealing steps, reduced short channel effects, higher carrier mobility, and lower leakage current. However, they can have greater threshold voltage variability than conventional transistors. The document provides details on the structure and operation of junctionless transistors, comparing them to traditional transistors and discussing their potential to enable further device miniaturization.
This document provides information about optical fiber communication systems. It discusses the key components of these systems including optical sources, modulators, optical fibers as the transmission medium, and photodetectors. It also outlines the historical development of fiber optic technology from early experiments in the late 19th century to current commercial systems. The advantages of optical fiber communication over electrical transmission are highlighted such as higher bandwidth, longer transmission distances, and immunity to electromagnetic interference.
There are two main types of optical fiber signal loss: scattering and absorption. Scattering losses include Rayleigh scattering caused by molecular irregularities and Mie scattering caused by larger defects. Absorption losses are caused by intrinsic material properties like ultraviolet and infrared absorption in silica glass, as well as extrinsic impurities introduced during manufacturing. Proper fiber design and high material purity can minimize these signal losses to enable effective optical fiber communication.
Minimally invasive spine surgeries (MISS) aim to minimize soft tissue damage during spinal procedures. MISS techniques using tubular retractors or endoscopes have been applied to procedures like discectomy, decompression, and fusion. MISS may provide benefits over open techniques like less blood loss, shorter hospital stays, and faster recovery. However, MISS also has disadvantages like a steep learning curve, dependence on technology, and higher initial costs. The applications of MISS continue to expand but further research is still needed to fully understand its advantages and disadvantages.
A Comparative Study of the Clinical and Functional Outcome Anterior Cruciate ...TheRightDoctors
A Comparative Study of the Clinical and Functional Outcome Anterior Cruciate Ligament Reconstruction Using Transportal and Transtibial Approach for Femoral Tunnel Drilling-Dr. Adarsh Reddy
1) What is Fiber Optics?
2) Structure of Fiber Optics.
3) Modes of Fiber Optics.
4) How It Is made.
5) Communication System.
6) Evolution of Fiber Optics.
7) Advantages/ Disadvantages.
8) Applications of Fiber Optics.
9) Conclusion.
Dr. Sunil Kumar Sharma's document discusses various functional neuroimaging modalities including fMRI, PET, and SPECT. It provides details on how each modality works, its advantages and disadvantages, and examples of its applications in mapping brain functions and depicting disease-related changes. Specific conditions discussed in relation to imaging findings include dementia, Parkinsonism, brain tumors, and epilepsy.
This presentation describes the common conditions, anatomy and the ideal ways to do and perform nerve conduction studies in lower limbs. It is nicely depicted with self explanatory pictures.
1. The document discusses optical fibers, specifically step index fibers. It describes step index fibers as having a core with a constant refractive index n1 surrounded by a cladding with a slightly lower refractive index n2.
2. It discusses several factors that determine the number of propagating modes in a step index fiber, including the V-number which is a function of the core radius, wavelengths, and refractive index differences. Fibers with V<2.405 support only one mode.
3. Dispersion effects in step index fibers include intermodal dispersion from different propagation speeds of fiber modes, and material dispersion from the wavelength dependence of the core refractive index.
Cortical dysplasia is a malformation of cortical development caused by abnormal neuronal migration or organization during brain development. It can cause intractable epilepsy and neurodevelopmental disorders like autism. The lecture discusses normal brain development and corticogenesis. It then covers specific malformations including focal cortical dysplasia, describing their histopathology and clinical correlates. Recent research suggests focal disruptions of cortical layering found in children with autism may represent early cortical dysplasia, providing insight into a potential cause of autism.
This document discusses photonic crystal fibers (PCFs). PCFs are composed of nanostructures that affect photon propagation through periodic refractive indices, similar to how semiconductor crystals affect electron motion. PCFs can guide light through two mechanisms: index guiding and photonic bandgap guiding. They have properties like endless single mode operation, large mode areas, and tunable dispersion. Special PCFs include double core fibers, highly birefringent fibers, and hollow core bandgap fibers. PCFs offer advantages over standard fibers like flexibility in core size and wavelengths used. Challenges include difficult fabrication and limited operating frequencies.
Optical fiber communication-Presented by Kiran DevkotaSujit Jha
This document discusses optical fiber communication and fiber optic cables. It covers the following key points:
- Fiber optics uses light to transmit information through glass or plastic strands. Unlike copper transmission, it is not electrical in nature.
- The basic components of a fiber optic cable are the core that carries light, cladding surrounding the core, a coating for protection, and a cable jacket.
- Fiber materials include silica glass, plastic, and plastic-clad fibers. Single-mode fiber has a small core for long distances, while multimode fiber has a larger core for short distances.
- Fiber optic communication has advantages like large bandwidth, small size, electrical isolation, and low
This document provides an overview of peripheral neuropathy, including:
1. It describes the anatomy of peripheral nerves and different types of peripheral neuropathies such as mononeuropathy, mononeuropathy multiplex, polyneuropathy, polyradiculopathy, and plexopathy.
2. It outlines the various clinical presentations of peripheral neuropathy including sensory, motor, and autonomic symptoms as well as patterns of nerve fiber involvement.
3. It discusses the etiology, clinical course, investigations and management of different peripheral neuropathies.
Competitive Intelligence to Decision Pattern by Elijah EzenduElijah Ezendu
Competitive Intelligence to Decision Pattern (CIDP) is a method of rating Corporate Competitive Intelligence Operations through patterns of systemic flow from Competitive Intelligence to Decision, thereby providing appropriate classification ranging from AAAAAAAA to DDDDDDDD.
This document summarizes key information about Guillain-Barré syndrome (GBS) and related acute inflammatory neuropathies. It describes the incidence and subtypes of GBS, including typical symptoms such as weakness and sensory disturbances. Electrodiagnostic findings are outlined, including conduction block, prolonged distal latencies, and reduced nerve conduction velocities supportive of demyelination. The time course of GBS and potential etiologies like infection are mentioned. Chronic inflammatory demyelinating polyneuropathy (CIDP) and multifocal motor neuropathy are also summarized, with details on clinical features and electrodiagnostic patterns that help differentiate these conditions from GBS.
This document summarizes information presented at a conference on immune-mediated neuropathies and treatment options for patients who do not respond to conventional therapies. It discusses various subtypes of chronic inflammatory demyelinating polyneuropathy (CIDP) and provides treatment guidelines. For patients who do not respond initially, it recommends reconsidering the diagnosis or trying immunosuppressant drugs, and more research is needed to determine their effectiveness for CIDP.
This document provides diagnostic criteria for chronic inflammatory demyelinating polyneuropathy (CIDP), including:
1) Clinical criteria for typical and atypical CIDP with inclusion/exclusion factors.
2) Definite, probable, and possible electrophysiological criteria involving compound muscle action potential tests.
3) Supportive diagnostic criteria including cerebrospinal fluid analysis, MRI findings, nerve conduction studies, and nerve biopsy results.
It also outlines inclusion/exclusion criteria and supportive criteria specifically for diagnosing pure sensory CIDP without motor involvement.
Therapeutic apheresis involves separating blood components outside the body to remove substances causing disease symptoms. There are two main types: donor apheresis produces blood components, while therapeutic apheresis treats diseases by removing toxins, antibodies, lipids, etc. from the blood. Therapeutic plasma exchange is commonly used to treat various autoimmune and inflammatory conditions by removing pathogenic substances from plasma. Guidelines provide evidence-based recommendations on appropriate uses of therapeutic apheresis. Conditions like Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy, and myasthenia gravis often respond well to therapeutic apheresis.
CIDP is a chronic acquired demyelinating neuropathy. It has two patterns - a continuous progressive course over months to years or a relapsing course with partial recovery between episodes. Diagnosis requires documentation of demyelination through electrodiagnostic testing, CSF analysis and sometimes nerve biopsy. Treatment includes corticosteroids, IVIG and plasmapheresis, which are effective in around 50-70% of patients. Corticosteroids are usually the first line treatment, starting with high dose prednisone and slowly tapering as response occurs.
Immunoglobulins market to 2019 demand in primary immunodeficiency (pi) and ...Reports Corner
GBI Research's report "Immunoglobulins Market to 2019 - Demand in Primary Immunodeficiency (PI) and Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) Potentially Supplemented by Approvals for Alzheimer's Disease" provides in-depth analysis of the global immunoglobulin market. The report analyzes the markets for immunoglobulin products in the US, the top five European countries (the UK, Germany, France, Italy and Spain) and Japan.
https://www.reportscorner.com/reports/20855/Immunoglobulins-Market-to-2019---Demand-in-Primary-Immunodeficiency-(PI)-and-Chronic-Inflammatory-Demyelinating-Polyneuropathy-(CIDP)-Potentially-Supplemented-by-Approvals-for-Alzheimers-Disease/
This document describes a case of a 32-year-old male who presented with weakness in all four limbs that progressed over a week. Based on examination and investigations, he was diagnosed with recurrent quadriparesis likely due to an autoimmune etiology of chronic inflammatory demyelinating polyneuropathy (CIDP) associated with systemic lupus erythematosus (SLE). He showed improvement in symptoms with intravenous steroids and plasma exchange.
Global Intravenous Immunoglobulin Market (By Application, Types and Geography...Allied Market Research
IVIG is a sterile solution of antibodies collected from healthy donors, which is administered through the veins into the body. Currently, the immunoglobulin industry is growing on account of increasing FDA/EMA approvals and government support. IVIG usage against the conditions within the criteria (i.e. FDA/EMA approved indications) have increased greatly and the largest increase found in Chronic Inflammatory demyelinating polyneuropathy (CIDP), Hypogammaglobulinemia and immunodeficiency diseases.
The GBS|CIDP Foundation International has officially recognized Mr. Sait Mentes Birlik as a Liaison for the organization in Turkey. As a Liaison, Mr. Birlik will represent the Foundation by conducting patient visitations in hospitals and raising awareness and support for Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy, and related conditions. The GBS|CIDP Foundation International is a global non-profit organization founded in 1980 to support individuals affected by GBS, CIDP, and related syndromes through programs focused on support, education, research, and advocacy.
This document provides information about chronic inflammatory demyelinating polyneuropathy (CIDP), including:
1) CIDP is an autoimmune disorder where the immune system attacks the peripheral nervous system, specifically targeting the myelin insulation around nerves.
2) Symptoms include numbness, tingling, muscle weakness, loss of reflexes, and abnormal sensations that typically start distally and progress proximally.
3) Diagnosis involves nerve conduction studies showing signs of demyelination in multiple nerves as well as EMG findings such as prolonged latencies and conduction blocks. Nerve biopsy may also show signs of inflammation and demyelination.
The document discusses the anatomy and types of neuropathies. It begins by describing the basic anatomy of nerves including neurons, axons, and myelin sheaths. It then defines and compares different types of neuropathies such as neuronopathies, radiculopathies, plexopathies, mononeuropathies, and polyneuropathies. Specific conditions like diabetic neuropathy, Guillain-Barré syndrome, and Charcot-Marie-Tooth disease are also summarized.
This document discusses different types of EMG electrodes used to measure jitter, including concentric needle electrodes and single fiber EMG electrodes. It presents data from studies measuring jitter with these electrodes in various muscles. Specifically, it shows jitter measurements are higher with concentric needle electrodes than single fiber electrodes in muscles from myasthenia gravis patients. The document also reviews the sensitivity of different diagnostic tests for myasthenia gravis, with jitter analysis and repetitive nerve stimulation having high sensitivity to detect the condition.
Bio molecular epigenetic mechanisms of unexplained complex condition neuro-...DOTTGIACOMORAO
Meccanismi biomolecolari epigenetici , disfunzione mitocondriale secondaria, modulazione della protein kinase C neuronale,oxidative and nitrosative stress endogenous molecules danger signals (DAMPs ) attività della alpha-N-acetylgalactosaminidase nella immuno-europatogenesi delle Sindromi immuno-neuro tossiche correlati a xenobiotici ambientali( endocrine disruptor, metalli pesanti, particolato ultrafine, micotossine)
IPOTESI DI MECCANISMI FISIOPATOGENETICI DI BASE
Alterazioni di meccanismi epigenetici: gli xenobiotici interferiscono sulla omeostasi della espressione genica a vari livelli:trascrizionale espressione dei recettori nucleari
,posttraduzionale (la modificazione post-traslazionale delle proteine (folding) delle glicoproteine)
aumento dello stress ossidativo associato ad un esaurimento de sisistemi antiossidanti cellulari;
ridotta capacità di detossificazione, polimorfismi genetici codificanti enzimi di resistenza stress ossidativo delle metallotioneine che modicano la tossicocinetica determinando
bioaccumulo di xenobiotici e metalli pesanti con maggiore suscettibilità e tossicità agli stessi
disfunzione Mitocondriale secondaria,: molti metalli solventi dinitrofenolo ,clorofenoli stirene agiscono da disaccoppiante della fosforilazione ossidativa inibiscono la ANT;
Disfunzione del citoscheletro repertati addotti di metalli pesanti sulla actina;
concentrazioni di piombo picomolecolari interferiscono con la proteinchinasi C nel cervello
tali alterazioni biochimiche si manifestano con
disregolazione del neuro–endocrino–immunitario, cross talk,disfunzione delle interazioni complesse tra il sistema immunitario e il sistema nervoso :
limbic neural sensitization. Studi su cavie supportano l’ipotesi del limbic system sensitization per la multiple chemical sensitivity : esposizione ripetuta a formaldeide ripetute produce plasticità neuronale che si manifesta come una maggiore sensibilità ai farmaci dopaminergici, una maggiore paura condizionata per l'odore associato con un evento avversione,e una maggiore prevenzione di odori, alterazioni del sonno affaticamento.
Lumache acquatiche da siti minerari si sono evoluti pe rrilevare ed evitare i metalli pesanti.
le lumache sono in grado di persistere perché hanno sviluppato la capacità di ridurre al minimo la loro esposizione a metalli evitando attivamente metalli nel loro ambiente
la cronica ripetuta a bassa intensità di stimolazione potrebbe provocare kindling dell'asse limbico-ipotalamico-pituitario.
Kindling potrebbe verificarsi anche per la stimolazione ad alta intensità dell'asselimbico-ipotalamico-pituitario.
Una volta che questo sistema è eccitato può sostenere un alto livello di eccitazione con minimo stimolo esternoe alla fine uesto potrebbe portare a ipocortisolismo.
Attività di sequestro può estendersi alle strutture adiacenti dell 'asse limbico-ipotalamico-pituitaria nel cervello,ch epotrebbe essere responsabile dei sintomi diversi che si verificano nella
Le modificazioni ambientali e le alterazioni degli stili di vita verificatesi negli ultimi decenni hanno favorito il moltiplicarsi di reazioni allergiche nella popolazione mondiale. Nell’ambito delle allergie Respiratorie, il risultato solo parziale raggiunto finora dai vaccini ed i pesanti effetti collaterali mostrati dai farmaci comunemente usati (antistaminici, cortisonici, etc.) ci ha da tempo stimolato a sperimentare l’efficacia dell’agopuntura su queste patologie.
Gli ottimi risultati ottenuti con la popolazione adulta ci hanno spinto a verificare la validità di questo approccio anche con individui allergici in età evolutiva.
Scopo di questo lavoro è presentare i risultati preliminari fin qui ottenuti.
1. “Neuropatie periferiche: S. di Guillain Barrè, Neuropatia
multifocale motoria, CIDP, Miastenia Gravis.
Immunomodulazione e terapia con immunoglobuline”
Ada Francia
Università ‘Sapienza’ di Roma
2.
3.
4. Autoreactive T-lymphocytes are activated by APCs in
the systemic immune compartment; these activated
neuritogenic lymphocytes cross the BNB in order to
enter the PNS. Within the PNS, T cells activate
macrophages that enhance phagocytic activity,
production of cytokines, the release of toxic
mediators and proinflammatory cytokines,
propagating demyelination and axonal loss. The
termination of the inflammatory response is mediated,
in part,by macrophages by the induction of T-cell
apoptosis and the release of anti-inflammatory
cytokines. APC, antigen-presenting cells; BNB,
blood–nerve barrier; PNS, peripheral nervous system
5. Uso di Ig e.v. nelle malattie neurologiche
Malattie Classe di evidenza
Sindrome di Guillain-Barrè I
CIDP Trattamenti acuti I
Trattamenti cronici III
MMN I
Polineuropatie con MGUS IgM I
IgG/IgA III
Miastenia grave Crisi miasteniche I
Trattamenti cronici IV
Miosite Dermatomiosite I
Polimiosite III/IV
Corpi inclusi I
Sindrome di Stiff-person I
Neuromiotonia III/IV
Sindromi Paraneoplastiche Sindrome di Lambert-Eaton II
Encefaliti limbiche / Polineuropatie /
degenerazione cerebellare subacuta
III/IV
Sclerosi Multipla R-R I
S P I
P P
Remielinizzazione I
8. Guillain Barrè Epidemiologia
• 1.2-1.9/100-000 in Europa;
• 0.6-4/100.00 nel mondo;
• 2/3 dei casi seguono ad infezioni
(Mycoplasma pneumoniae, Citomegalovirus,
Campylobacter),vacccinazioni
• Incidenza di interventi chirurgici e traumatismi
.
13. ….Perche’
• Minore effetto sulla tossicità degli
anticorpi antiganglioside;
• Attivazione del complemento;
• Inibizione dell’azione “depurativa” dei
macrofagi;
• Inibizione del processo di
remielinizzazione
14. Miastenia gravis
• 1672 prima descrizione;
• 1960 prime terapie (cortisonici,
immunosoppressivi);
• 1970 Plasmaferesi;
• Anni ‘80 immunoglobuline e.v.
19. Crisi miastenica
• Acuta , grave compromissione della
funzionalità respiratoria che richiede
trattamento terapeutico intensivo….
• Terapia aferetica;
• Terapia con Immunoglobuline endovena
20. Poliradicoloneuropatia infiammatoria
demielinizzante cronica (CIDP)
Malattia immuno mediata prevalenza 1-2/100.000 adulti
Andamento: progressivo
recidivante
Sintomi :80% motori e sensitivi
20% solo motori
<1% solo sensitivi
Diagnosi differenziale:
21. Meccanismi eziopatogenetici non chiari:
• Attivazione delle cellule T ( Pollard, 2002).
• Anticorpi diretti contro proteine meiliniche (Allen et al., 2005).
• Studi hanno mostrato presenza di cellule T regolatorie nei
nell’endonervio di nervi colpiti (Illes et al., 2000; Hayday and
Tigelaar, 2003).
Possibili meccanismi d’azione
delle immunoglobuline:
•Inibizione produzione anticorpi
•Neutralizzazione anticorpi patogeni
•Diminuzione della citotossicità anticorpo
dipendentente attraverso il blocco del
recettore Fc sui macrofagi
22. Criteri Diagnostici
CRITERI CLINICI INDISPENSABILI
1. ipostenia simmetrica prossimale ai 4 arti per almeno 2 mesi
2. deficit sensitivi meno importanti
3. ipo/areflessia profonda
4. talvolta coinvolgimento dei nervi cranici
5. decorso cronico o remissioni e ricadute.
DIAGNOSI LABORATORISTICA
1. Presenza, nel LIQUOR, di dissociazione albumino-citologica.
EMG
1. VdC rallentate
2. Blocchi di conduzione
3. Aumento delle latenze distali
24. Evidenza nei trials :
(The cochrane Library 2009, Issue 4)
•miglioramento della disabilità dopo infusione di
IVIg almeno per 2 -6 settimane rispetto al placebo
•similare efficacia rispetto a plasmaferesi e
prednisolone x os , ma in alcuni studi benefici IVIg
per 24 ed anche 48 settimane
CIDP
25. NEUROPATIA MOTORIA MULTIFOCALE (MMN)
Nel 1985, Parry e Clarke hanno studiato la conduzione nervosa in 2 pazienti con una
sindrome del secondo motoneurone caratterizzata da una perdita di forza progressiva,
asimmetrica e distale senza disturbi sensitivi e hanno rinvenuto, allo studio
elettrofisiologico, la presenza di blocchi di conduzione motoria. Subito dopo sono stati
descritti altri casi con caratteristiche cliniche e neurofisiologiche simili.
E’ caratterizzata clinicamente da:
•Debolezza lentamente progressiva e asimmetrica prevalentemente distale ,AASS>AAII
(dorsiflessione polso e piede, ridotta prensione);
•Crampi muscolari, fascicolazioni in 2/3 dei pazienti;
•Riduzione dei riflessi osteo-tendinei.
•Atrofia muscolare che si sviluppa gradualmente negli anni.
•Paralisi unilatarale o bilaterale del nervo frenico può insorgere anche all’esordio.
•Raro coinvolgimento dei nervi cranici
•Assenza di disturbi sensitivi.
Maschi:femmine:2,6
Età media d’esordio: 40 anni (range 20-70 aa) con insorgenza nell’80% tra i 20 e i 50 aa
Prevalenza: 1-2/100.000
27. DIAGNOSI DIFFERENZIALE
Jan-Thies H Van Asseldonk, Hessel Franssen, Renske M Van den Berg-Vos, John H J Wokke, Leonard H
Van den Berg Lancet Neurol 2005; 4: 309–19
28. DIAGNOSI
NEUROFISIOLOGIA: Caratteristica presenza di blocchi di conduzione. Anche se…
La degenerazione assonale e l’entità del blocco di conduzione sono in relazione con il
grado e la reversibilità del deficit di forza. L’atrofia muscolare, la bassa ampiezza del
CMAP a livello distale, i patterns di denervazione e di reinnervazione rappresentano
elementi elettromiografici tipici in pazienti con MMN, anche in quelli con breve durata di
malattia.
LABORATORIO: elevati titoli di IgM contro il Ganglioside GM1nel 50% dei casi
(range 22- 85%)
Positività anche in altre patologie del secondo motoneurone, SLA, CIDP e in soggetti sani
suggerendo sensibilità e specificità limitate
Ma in patologie diverse da MMN titoli anticorpali bassi
Una metanalisi suggerisce che la probabilità di diagnosi di MMN in presenza di clinica
congrua e positività di IgM anti GM1 sale dal 20% al 50-85%
NEUROIMAGING : MRI potrebbe aiutare a differenziare MMN da altre patologie del secondo
motoneurone; iperintensità di segnale in T2 nel 40–50% dei pazienti con MMN.
29. Patofisiologia
BIOPSIA: Pochi studi effettuati dimostrano maggiore coinvolgimento assonale. Sporadici
infiltrati infiammatori rispetto alla CIDP (meccanismo patogenetico diverso). Alcuni quadri
mostrano sia degenerazione assonale che demielinizzazione.
IMMUNOPATOLOGIA: La positiva risposta a terapie, il riscontro di IgM anti GM1, l’espressione
di tale ganglioside a livello assonale e della membrana mielinica suggeriscono un possibile
ruolo eziopatogenetico delle IgM anti GM1.
Il coinvolgimento selettivo delle fibre motorie potrebbe essere dovuto a differenze nella
composizione e distribuzione del ganglioside tra le fibre motorie e sensitive.
In alcuni studi eseguiti su animali da esperimento, e stata dimostrata sia la
demielinizzazione anticorpo-mediata che il blocco dei canali del sodio voltaggio dipendenti a
livello dei nodi di Ranvier.
Ma i siti di legame degli anti GM1 e i canali del sodio non sono colocalizzati. Inoltre,
nell’uomo IgM anti-GM1 modulano l’omeostasi intracellulare del calcio , probabilmete per
attivazione di canali di tipo L presenti anche nelle fibre motorie.
Non è dimostrato l’assoluto ruolo patogenetico di tali anticorpi (possibili altri fattori)
30. Il meccanismo che sottende alla distruzione dell’assone nella
MMN e alla generazione dei blocchi di conduzione non è ancora
completamente chiarito. Dubbia permane, inoltre, la loro
interdipendenza. Alcuni studi hanno ipotizzato e confermato
l’esistenza di un meccanismo etiopatogenetico comune che causi
il blocco di conduzione in alcuni assoni e la degenerazione
assonale in altri.
Tali studi dimostrano, infatti, che gli anticorpi anti-GM1 che si
legano ad alcuni epitopi presenti a livello dell’assolemma nodale e
della mielina paranodale determinano sia il blocco di conduzione
che la degenerazione assonale, mentre il loro legame ad epitopi
dei motoneuroni spinali determinerebbe soltanto la perdita
dell’assone.
31. TERAPIA
Ig ev TERAPIA DI PRIMA SCELTA!
da 0.4 g/kg a settimana fino a 1–2 g/kg per 2-5 gg al mese o in fase di ricaduta
o immediatamente prima, di solito dopo 3-8 settimane.
durata dell’efficacia: alcune settimane necessità di terapia di
mantenimento nella maggiorparte dei casi
Riduzione dell’efficacia dopo un lungo periodo di trattamento
Necessari studi di efficacia sui trattamenti a lungo termine e standardizzazione
delle dosi
32. Possibili meccanismi d’azione delle Ig ev
• Modulazione di autoanticorpi
specifici
• Inibizione dell’attivazione del
complemento e della
formazione del MAC
• Modulazione dei ricettori Fc
• Soppressione di citochine e
molecole di adesione
• Modulazione delle funzioni
cellule-T
• Interferenza con il
riconoscimento di antigeni
• Possibile effetto sulla
remielinizzazione
MG, LEMS, SPS,
DM, GBS, CIDP, MG
GBS, CIDP
Miopatie infiammatorie,
neuropatie demielinizzanti,
MG
GBS, CDP, Miopatie
infiammatorie
GBS, CDP
33. Effetti delle Ig e.v.
sui linfociti B e anticorpi
•Anti-idiotipo contro le membrane recettori di cellule B
•Fc-mediato con inibizione di anticorpi produttori di Cellule B
•Anticorpi anti-CD 5 diretti contro un sottoinsieme di cellule B
•Interferenza con la differenziazione dei linfociti B
•Inibizione della produzione di IL-6 necessaria alla secrezione di
anticorpi dalle plasmacellule
•Induzione di apoptosi dei linfociti B
•Neutralizzazione degli auto-anticorpi anti-idiotipo mediata
•Aumento del catabolismo di anticorpi attraverso l’FcRn intracellulare
34. Effetti delle Ig e.v. sul Complemento
• Legame con C1
• Legame con C3b
• Legame con C4
• Aumento del consumo diC3b
• Legame con l’anafilotossina C3a e C5a
35. Meccanismi delle Ig e.v. che influenzano
le cellule T
•Anticorpi contro la catena β del recettore dei linfociti T
•Anticorpi contro CD4 e CD8
•Solubilizzazione di CD4 e CD8
•Anticorpi contro molecole HLA
•Anticorpi contro superantigeni
•Anticorpi contro i recettori CCRS delle chemochine
•Inibizione della maturazione delle cellule dendritiche
•Inibizione dell’attivazione dei linfociti T
36. Ig e.v. e migrazione cellulare
•Modulazione della espressione delle
molecole di adesione tipo ICAM
•Anticorpi contro integrine
•Anticorpi contro RGD
•Anticorpi contro CCRS
37. Effetti Fc mediati delle Ig e.v.
• Complemento
• Fagociti
• Citokine
• Metabolismo IgG
• IG e.v. legano C1q, C3b, e C4
• ↑ Consumo di C3b
• Blocco dei recettori Fc
• Induzione dell’espressione dei recettori
inibitori FcγIIB
• Inibizione dei linfociti B
• Induzione della secrezione di citochine
e produzione NO
• Blocco dell’ FcRn (protettivo)
38. Proposto meccanismo d’azione delle Igev sull’immuinità cellulare (Durandy et al
Clinical and experimental immunology 2009
40. CIDP ..CASISTICA PERSONALE
PAZIENTI
20 F
15M
ETA’ 21 78
DURATA MALATTIA 3 mesi 6
anni
TERAPIA:
•CORTISONICA 19
•PLASMAFERETICA 8
•IMMUNOSOPPRESSIVA 5
•NESSUNA 5
FOLLOW UP:
•LIBERO DA TERAPIA 5
•ANCORA IN TRATTAMENTO 7
•TERAPIAADDITIVA 6
•DROP OUT 2
41. ELEMENTI PROGNOSTICI FAVOREVOLI
• ETA’ NON AVANZATA DEL PAZIENTE
• DURATA DI MALATTIA INFERIORE A 1 ANNO
• ASSENZA DI DISCREPANZA DEL DEFICIT TRA ARTI
SUPERIORI E INFERIORI
• PREVALENTE COINVOLGIMENTO MOTORIO
• PRECOCE APPROCCIO TERAPEUTICO
..CASISTICA PERSONALE
42. SINDROME DI GUILLAIN BARRE’
..CASISTICA PERSONALE
PAZIENTI
9 F
16 M
ETA’ 30 57
DURATA MALATTIA 2 gg. 1 sett.
TERAPIA:
•CORTISONICA 10
•PLASMAFERETICA 6
•NESSUNA 9
PER I 9 PAZIENTI SONO STATI
ESEGUITI DA 2 A 3 CICLI DI
IMMUNOGLOBULINE.
IL MIGLIORAMENTO E’
INIZIATO ALLA 3° SETTIMANA
44. CONSIDERAZIONI ….MG
• RISPOSTA POSITIVA IN TUTTI I PAZIENTI
• DIMINUZIONE DELLE TERAPIE PREESISTENTI
• PER OGNI PAZIENTE SONO STATI EFFETTUATI 3 CICLI DI
TERAPIA INFUSIONALE CON INTERVALLI DI 28 GIORNI
• NECESSITA’ DI TRATTAMENTI A CADENZA SEMESTRALE
IN 5 PAZIENTI
• L’ANDAMENTO ANTICORPALE E’ RISULTATO NON
CORRELABILE
CASISTICA PERSONALE
45. Ann. Neurol. 2009
Pharmacokinetics of Intravenous
Immunoglobulin and Outcome in
Guillain-Barre´ Syndrome.
K. Kuitwaard, J. de Gelder, A. P. Tio Gillen, W.
C. J. Hop.T. van Gelder, A. W. van
Toorenenbergen, P. A. van Doorn, and B. C.
Jacobs
46. Conclusioni
• Le immunoglobuline (IVIg),rivestono un ruolo importante nel trattamento di
molti disordini neuroimmunologici;
• Attualmente molti degli effetti terapeutici delle immunoglobuline sono ascrivibili a
meccanismi multipli tra loro collegati;
• ll trattamento con IVIg è da considerarsi di prima scelta nella sindrome di
Guillain Barrè, CIDP, MMN
• Sicuro effetto si evidenzia nella miastenia “non responder” e nelle crisi
miasteniche; sono di seconda scelta per la dermatomiosite e per la stiff-person
syndrome;
• Possibili nuove indicazioni includono: la sindrome post-polio, la narcolessia, la
m. di Alzheimer, le neuropatie dolorose, alcune forme di epilessia
• Un maggiore uso di IVIg potrebbe avere un risvolto negativo sulla spesa
sanitaria ma solo nell’immediato.
• Nuove formilazioni: Ig sottocute