Cells of the nervous system: Neurons & Glial cells
▫ Neurons:
A neuron is Formed of:
Cell body:
▫ contains most of the cytoplasm & organelles
Cytoplasmic extensions:
▫ include an axon & many dendrites
Overvie
Presentation on Fatty Acid Biosynthesis in cell (Creation of fatty acids from acetyl-CoA and NADPH through the action of enzymes called fatty acid synthases).
Presentation on Fatty Acid Biosynthesis in cell (Creation of fatty acids from acetyl-CoA and NADPH through the action of enzymes called fatty acid synthases).
Metabolic Fate of Pyruvate and Cori cycle and Alanine cycle Cori & Alanine cy...Amany Elsayed
Metabolic Fate of Pyruvate and Cori cycle and Alanine cycle Cori & Alanine cycle and Lactate Dehydrogenase Deficiency (LDHA) and Malate aspartate shuttle (cycle) and Glycerol phosphate shuttle and Mitochondrial shuttle
All tissues have some capability for synthesis of the non-essential amino acids, amino acid remodeling, and conversion of non-amino acid carbon skeletons into amino acids and other derivatives that contain nitrogen. However, the liver is the major site of nitrogen metabolism in the body.
Cerebral circulation is the movement of blood through a network of cerebral arteries and veins supplying the brain. The rate of cerebral blood flow in an adult human is typically 750 milliliters per minute, or about 15% of cardiac output. Arteries deliver oxygenated blood, glucose and other nutrients to the brain. Veins carry "used or spent" blood back to the heart, to remove carbon dioxide, lactic acid, and other metabolic products.[1] Because the brain would quickly suffer damage from any stoppage in blood supply, the cerebral circulatory system has safeguards including autoregulation of the blood vessels. The failure of these safeguards may result in a stroke. The volume of blood in circulation is called the cerebral blood flow. Sudden intense accelerations change the gravitational forces perceived by bodies and can severely impair cerebral circulation and normal functions to the point of becoming serious life-threatening conditions.
Lipoprotein metabolism - (transport of lipids in the Blood)Ashok Katta
This presentation explains metabolism of lipoproteins (Chylomicron, VLDL, LDL, HDL) in very simple way. The presentation contains lots of animation to explain metabolism of individual lipoproteins.
Metabolic Fate of Pyruvate and Cori cycle and Alanine cycle Cori & Alanine cy...Amany Elsayed
Metabolic Fate of Pyruvate and Cori cycle and Alanine cycle Cori & Alanine cycle and Lactate Dehydrogenase Deficiency (LDHA) and Malate aspartate shuttle (cycle) and Glycerol phosphate shuttle and Mitochondrial shuttle
All tissues have some capability for synthesis of the non-essential amino acids, amino acid remodeling, and conversion of non-amino acid carbon skeletons into amino acids and other derivatives that contain nitrogen. However, the liver is the major site of nitrogen metabolism in the body.
Cerebral circulation is the movement of blood through a network of cerebral arteries and veins supplying the brain. The rate of cerebral blood flow in an adult human is typically 750 milliliters per minute, or about 15% of cardiac output. Arteries deliver oxygenated blood, glucose and other nutrients to the brain. Veins carry "used or spent" blood back to the heart, to remove carbon dioxide, lactic acid, and other metabolic products.[1] Because the brain would quickly suffer damage from any stoppage in blood supply, the cerebral circulatory system has safeguards including autoregulation of the blood vessels. The failure of these safeguards may result in a stroke. The volume of blood in circulation is called the cerebral blood flow. Sudden intense accelerations change the gravitational forces perceived by bodies and can severely impair cerebral circulation and normal functions to the point of becoming serious life-threatening conditions.
Lipoprotein metabolism - (transport of lipids in the Blood)Ashok Katta
This presentation explains metabolism of lipoproteins (Chylomicron, VLDL, LDL, HDL) in very simple way. The presentation contains lots of animation to explain metabolism of individual lipoproteins.
What is Alzheimer's disease? pathophysiology of disease, treatment of disease. If there is any update regarding the information provided, your comments are welcomed
Alzheimer's disease is a neurodegenerative disorder with severe dementia. Due to the accumulation of Beta-Amyloid proteins acetyl-choline producing neurons are getting degenerated. Alzheimer's disease is one of the most devastating brain disorders of elderly humans. It is an under-treated and under-recognized disease that is becoming a major public health problem.
Alzheimer's disease is a progressive disorder that causes brain cells to degenerate and die. It is the most common cause of dementia — a continuous decline in thinking, behavioral and social skills that disrupts a person's ability to function independently.
AD is the most common neurodegenerative disorder and it is clinically defined by a slowly progressing loss of cognitive functions, primarily memory impairment.
Similar to 1- metabolism of the brain (I) 2012-13.pdf (20)
1- Biochemical and molecular basis of lung diseases .pptMohamed Afifi
Recognize the biochemical structure and function of pulmonary surfactant
Discuss biochemical basis of respiratory distress syndrome
List the differences between collagen and elastin.
Identify the biochemical basis of lung emphysema due to alpha one antitrypsin deficiency.
Outline the biochemical and molecular basis of cystic fibrosis
Mention the diagnosis and treatment of cystic fibrosis
Definition f microorganism
A microorganism, or microbe, is an organism of microscopic size, which may exist in its single-celled form or as a colony of cells
Fate of Absorbed Amino Acids
Absorbed amino acids from diet are mixed with the amino acids produced from
hydrolysis of body protein and those synthesized in the body to form a common
amino acid pool (about 100g). This pool is drawn upon for anabolism and for
catabolism of amino acids.
Anabolic Fate
-These include the synthesis of proteins e.g. tissue, milk, and plasma proteins,
enzymes, and some hormones.
-They also include the synthesis of other nitrogenous substances e.g. glutathione,
adrenaline, thyroxine, melanin, niacin, purines, pyrimidines, aminosugars, and the
nitrogenous bases of phospholipids.
Catabolic Fate
-Most catabolic reactions are preceded by cleavage of the amino acids into ammonia
and the carbon skeleton (usually in the form of an -keto acid).
-The ammonia is mostly converted to urea, which is excreted in urine.
-Little ammonia is also excreted in urine. The carbon skeleton m
Cells of the nervous system: Neurons & Glial cells
▫ Glial cells:
most abundant cells, are of 3 main types
A. Microglia: Phagocytic (immune) cells,
B. Astrocytes: Support & nutrition of the neurons
(provide neurons with lactate from glucose and
regulate the content of ECF by removing K+ &
excess neurotransmitters)
C. Oligodendrocytes: form myelin sheathe in CNS
Schwan cells form myelin sheaths in PNS
Ependymal cells: line brain & spinal cord cavities
using their cilia to allow for the circulation of the
The starting template material is RNA not DNA ( as in PCR assays for the diagnosis of viral infections)
RNA cannot serve as a template for PCR, (RNA is not a substrate for the Taq DNA polymerases commonly utilised in PCR.) Therefore reverse transcription is combined with PCR to convert RNA into a complementary DNA (cDNA)) suitable for PCR
The first step in this procedure is to convert the RNA molecules into single-stranded complementary DNA (cDNA) (Figure 9.20). Once this preliminary step has been carried out, the PCR primers and Taq polymerase are added and the experiment proceeds exactly as in the standard technique
Sanger sequencing: the most popular method first devised by Fred Sanger and colleagues in the mid-1970
DNA to be sequenced serves as a template for DNA synthesis.
A DNA primer is designed to be a starting point for DNA synthesis by DNA polymerase on the strand of DNA to be sequenced.
Four individual DNA synthesis reactions are performed.
The four reactions include normal A, G, C, and T deoxynucleotide triphosphates (dNTPs), and each contains a low level of one of four dideoxynucleotide triphosphates (ddNTPs): ddATP, ddGTP, ddCTP, or ddTTP.
Sanger sequencing: the most popular method first devised by Fred Sanger and colleagues in the mid-1970
DNA to be sequenced serves as a template for DNA synthesis.
A DNA primer is designed to be a starting point for DNA synthesis by DNA polymerase on the strand of DNA to be sequenced.
Four individual DNA synthesis reactions are performed.
The four reactions include normal A, G, C, and T deoxynucleotide triphosphates (dNTPs), and each contains a low level of one of four dideoxynucleotide triphosphates (ddNTPs): ddATP, ddGTP, ddCTP, or ddTTP.Sanger sequencing: the most popular method first devised by Fred Sanger and colleagues in the mid-1970
DNA to be sequenced serves as a template for DNA synthesis.
A DNA primer is designed to be a starting point for DNA synthesis by DNA polymerase on the strand of DNA to be sequenced.
Four individual DNA synthesis reactions are performed.
The four reactions include normal A, G, C, and T deoxynucleotide triphosphates (dNTPs), and each contains a low level of one of four dideoxynucleotide triphosphates (ddNTPs): ddATP, ddGTP, ddCTP, or ddTTP.
Sanger sequencing: the most popular method first devised by Fred Sanger and colleagues in the mid-1970
DNA to be sequenced serves as a template for DNA synthesis.
A DNA primer is designed to be a starting point for DNA synthesis by DNA polymerase on the strand of DNA to be sequenced.
Four individual DNA synthesis reactions are performed.
The four reactions include normal A, G, C, and T deoxynucleotide triphosphates (dNTPs), and each contains a low level of one of four dideoxynucleotide triphosphates (ddNTPs): ddATP, ddGTP, ddCTP, or ddTTP.
The starting template material is RNA not DNA ( as in PCR assays for the diagnosis of viral infections)
RNA cannot serve as a template for PCR, (RNA is not a substrate for the Taq DNA polymerases commonly utilised in PCR.) Therefore reverse transcription is combined with PCR to convert RNA into a complementary DNA (cDNA)) suitable for PCR
The first step in this procedure is to convert the RNA molecules into single-stranded complementary DNA (cDNA) (Figure 9.20). Once this preliminary step has been carried out, the PCR primers and Taq polymerase are added and the experiment proceeds exactly as in the standard technique
The starting template material is RNA not DNA ( as in PCR assays for the diagnosis of viral infections)
RNA cannot serve as a template for PCR, (RNA is not a substrate f
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Care must be taken to preserve protein structure and function after it is removed
from its natural environment where it was stable.
• pH – To prevent denaturation or loss of function, proteins are placed in buffered
solutions at or near their native pH.
• Temperature – Protein purification is normally carried at low temperature ~ 0°C.
while some proteins are thermally stable at high temperatures.
• Inhibition of proteases
• Retardation of microbes that can destroy proteins
Sodium azide is often used
Salting-In: Most globular proteins tend to become
increasingly soluble as the ionic strength is raised due to
the addition of salt. This phenomenon is known as saltingin of proteins.
• Salting-out: As the salt concentration increases, this
lead to diminishment of electrostatic attraction between
protein molecules by the presence of abundant salt ions.
This phenomenon is known as salting-out of proteins.
• The salt concentration at which protein precipitates differs
from one protein to another.
• Salting out is one of the most commonly used protein
purification procedures.
• Ammonium sulfate is the most commonly used reagent
- High solubility (3.9 M in water at 0 ºC)
- High ionic strength solution can be made (up to 23.5 in
water at 0 ºC)
There are four steps of ion-exchange chromatography:
1. Equilibration – stabilization of the ion-exchangers with oppositely
charged ions in the buffer. E.g: Na+Cl2. Sample application and wash (Protein bound to the ion-exchangers
remain attached while other gets removed during wash)
3. Elution – Removal of bound protein from the ion exchangers with the
help of increased concentration of elution buffer.
4. Regeneration – Preparing the ion exchangers for the next round of
protein purification
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Size-Exclusion (or molecular
exclusion) Chromatography
•Molecules are separated
according to differences in their
size as they pass through a
hydrophilic polymer
•Polymer beads composed of
cross-linked dextran (dextrose)
which is highly and uniformly
porous (like Swiss cheese)
•Large proteins come out first
(can’t fit in pores), small proteins
come out last (get stuck in the
por
There are four steps of ion-exchange chromatography:
1. Equilibration – stabilization of the ion-exchangers with oppositely
charged ions in the buffer. E.g: Na+Cl2. Sample application and wash (Protein bound to the ion-exchangers
remain attached while othe
Willie Nelson Net Worth: A Journey Through Music, Movies, and Business Venturesgreendigital
Willie Nelson is a name that resonates within the world of music and entertainment. Known for his unique voice, and masterful guitar skills. and an extraordinary career spanning several decades. Nelson has become a legend in the country music scene. But, his influence extends far beyond the realm of music. with ventures in acting, writing, activism, and business. This comprehensive article delves into Willie Nelson net worth. exploring the various facets of his career that have contributed to his large fortune.
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Introduction
Willie Nelson net worth is a testament to his enduring influence and success in many fields. Born on April 29, 1933, in Abbott, Texas. Nelson's journey from a humble beginning to becoming one of the most iconic figures in American music is nothing short of inspirational. His net worth, which estimated to be around $25 million as of 2024. reflects a career that is as diverse as it is prolific.
Early Life and Musical Beginnings
Humble Origins
Willie Hugh Nelson was born during the Great Depression. a time of significant economic hardship in the United States. Raised by his grandparents. Nelson found solace and inspiration in music from an early age. His grandmother taught him to play the guitar. setting the stage for what would become an illustrious career.
First Steps in Music
Nelson's initial foray into the music industry was fraught with challenges. He moved to Nashville, Tennessee, to pursue his dreams, but success did not come . Working as a songwriter, Nelson penned hits for other artists. which helped him gain a foothold in the competitive music scene. His songwriting skills contributed to his early earnings. laying the foundation for his net worth.
Rise to Stardom
Breakthrough Albums
The 1970s marked a turning point in Willie Nelson's career. His albums "Shotgun Willie" (1973), "Red Headed Stranger" (1975). and "Stardust" (1978) received critical acclaim and commercial success. These albums not only solidified his position in the country music genre. but also introduced his music to a broader audience. The success of these albums played a crucial role in boosting Willie Nelson net worth.
Iconic Songs
Willie Nelson net worth is also attributed to his extensive catalog of hit songs. Tracks like "Blue Eyes Crying in the Rain," "On the Road Again," and "Always on My Mind" have become timeless classics. These songs have not only earned Nelson large royalties but have also ensured his continued relevance in the music industry.
Acting and Film Career
Hollywood Ventures
In addition to his music career, Willie Nelson has also made a mark in Hollywood. His distinctive personality and on-screen presence have landed him roles in several films and television shows. Notable appearances include roles in "The Electric Horseman" (1979), "Honeysuckle Rose" (1980), and "Barbarosa" (1982). These acting gigs have added a significant amount to Willie Nelson net worth.
Television Appearances
Nelson's char
Natural farming @ Dr. Siddhartha S. Jena.pptxsidjena70
A brief about organic farming/ Natural farming/ Zero budget natural farming/ Subash Palekar Natural farming which keeps us and environment safe and healthy. Next gen Agricultural practices of chemical free farming.
Artificial Reefs by Kuddle Life Foundation - May 2024punit537210
Situated in Pondicherry, India, Kuddle Life Foundation is a charitable, non-profit and non-governmental organization (NGO) dedicated to improving the living standards of coastal communities and simultaneously placing a strong emphasis on the protection of marine ecosystems.
One of the key areas we work in is Artificial Reefs. This presentation captures our journey so far and our learnings. We hope you get as excited about marine conservation and artificial reefs as we are.
Please visit our website: https://kuddlelife.org
Our Instagram channel:
@kuddlelifefoundation
Our Linkedin Page:
https://www.linkedin.com/company/kuddlelifefoundation/
and write to us if you have any questions:
info@kuddlelife.org
WRI’s brand new “Food Service Playbook for Promoting Sustainable Food Choices” gives food service operators the very latest strategies for creating dining environments that empower consumers to choose sustainable, plant-rich dishes. This research builds off our first guide for food service, now with industry experience and insights from nearly 350 academic trials.
"Understanding the Carbon Cycle: Processes, Human Impacts, and Strategies for...MMariSelvam4
The carbon cycle is a critical component of Earth's environmental system, governing the movement and transformation of carbon through various reservoirs, including the atmosphere, oceans, soil, and living organisms. This complex cycle involves several key processes such as photosynthesis, respiration, decomposition, and carbon sequestration, each contributing to the regulation of carbon levels on the planet.
Human activities, particularly fossil fuel combustion and deforestation, have significantly altered the natural carbon cycle, leading to increased atmospheric carbon dioxide concentrations and driving climate change. Understanding the intricacies of the carbon cycle is essential for assessing the impacts of these changes and developing effective mitigation strategies.
By studying the carbon cycle, scientists can identify carbon sources and sinks, measure carbon fluxes, and predict future trends. This knowledge is crucial for crafting policies aimed at reducing carbon emissions, enhancing carbon storage, and promoting sustainable practices. The carbon cycle's interplay with climate systems, ecosystems, and human activities underscores its importance in maintaining a stable and healthy planet.
In-depth exploration of the carbon cycle reveals the delicate balance required to sustain life and the urgent need to address anthropogenic influences. Through research, education, and policy, we can work towards restoring equilibrium in the carbon cycle and ensuring a sustainable future for generations to come.
Characterization and the Kinetics of drying at the drying oven and with micro...Open Access Research Paper
The objective of this work is to contribute to valorization de Nephelium lappaceum by the characterization of kinetics of drying of seeds of Nephelium lappaceum. The seeds were dehydrated until a constant mass respectively in a drying oven and a microwawe oven. The temperatures and the powers of drying are respectively: 50, 60 and 70°C and 140, 280 and 420 W. The results show that the curves of drying of seeds of Nephelium lappaceum do not present a phase of constant kinetics. The coefficients of diffusion vary between 2.09.10-8 to 2.98. 10-8m-2/s in the interval of 50°C at 70°C and between 4.83×10-07 at 9.04×10-07 m-8/s for the powers going of 140 W with 420 W the relation between Arrhenius and a value of energy of activation of 16.49 kJ. mol-1 expressed the effect of the temperature on effective diffusivity.
2. Learning Objectives:
• Explain the chemical composition of the brain,
nervous tissue and myelin
• Discuss the functions of Cholesterol in the CNS
• Identify the characteristic abnormalities in
Alzheimer’s Disease (AD)
• Explain the effects of some natural products on
AD
3. • Central Nervous System (CNS):
▫ Brain and Spinal cord
• Peripheral Nervous System (PNS):
▫ Receptors and Nerves (sensory & motor)
• The CNS is composed of two types of nervous tissues:
i) Gray matter which contains cell bodies,
ii) white matter which contains myelinated axons
Overview of the Nervous System
4. •Cells of the nervous system: Neurons & Glial cells
▫ Neurons:
–A neuron is Formed of:
–Cell body:
▫ contains most of the cytoplasm & organelles
–Cytoplasmic extensions:
▫ include an axon & many dendrites
Overview of the Nervous System (cont,)
5. • Cells of the nervous system: Neurons & Glial cells
▫ Glial cells:
– most abundant cells, are of 3 main types
A. Microglia: Phagocytic (immune) cells,
B. Astrocytes: Support & nutrition of the neurons
(provide neurons with lactate from glucose and
regulate the content of ECF by removing K+ &
excess neurotransmitters)
C. Oligodendrocytes: form myelin sheathe in CNS
– Schwan cells form myelin sheaths in PNS
– Ependymal cells: line brain & spinal cord cavities
using their cilia to allow for the circulation of the
CSF
Overview of the Nervous System (cont,)
6. Chemical composition of the brain
• About 80% of the brain tissue is water
• Most of the brain dry weight is lipids (cholesterol,
phospholipids & glycolipids)
• The remainder of the brain dry weight is proteins
mainly in the neurons and the glial cells
7.
8. Nervous tissue Lipids
•Phospholipids are the most abundant lipids in brain
•Brain Phospholipids are:
▫ Phosphatidylethanolamine (cephalin),
▫ Phosphatidylcholine (lethicin),
▫ Sphingomyelin,
▫ Phosphatidylinositol ,
▫ Phosphatidylserine
▫ Plasmalogen
9. Nervous tissue Lipids
•Cholesterol is the second most abundant substance in
the brain. About 25% of body cholesterol is present in
the nervous tissue.
•Most of cholesterol of adult brain is un-esterified.
Cholesterol easters are found in relatively high
concentrations at sites of active myelinization
•Many of the fatty acids in nervous tissue are
unsaturated and have long carbon chains.
•Brain galactolipids are Cerebrosides, Sulfatides &
Gangliosides
10. Nervous tissue Proteins:
•3 proteins have received some attention:
▫S-100:
–highly acidic protein: 30% of its amino acids are glutamic & aspartic acids
–found in large amounts in glial cells & in small amounts in neurons
–composed of 3 non-identical subunits & has a high affinity for Ca2+
▫Isozyme of enolase (2-phosphoglycerate phosphoenopyruvate)
–highly acidic protein
–found mainly in neurons
▫Both proteins have been implicated with memory or learning
ability of the brain
▫Calmodulin: is needed for the Ca2+-dependent:
–activation of cyclic nucleotide phosphodiesterase enzyme
–release of acetylcholine & nor-epinephrine from their vesicular stores.
11. Nervous tissue Proteins (cont.,):
•The Cytoskeleton of Neurons & Glial cells is made of:
▫ Microtubules:
– composed of both alpha and beta tubulin,
– important for cytoskeletal framework.
▫ Microfilaments:
– composed of actin;
– important for axoplasmic transport
▫ Neruofilaments:
– composed of tau proteins [microtubule-associated protein (MAP)]
– important for cytoskeletal integrity
– tau proteins interact with tubulin to stabilize microtubules, they
degenerate in Alzheimer’s disease through abnormal
phosphorylation
12.
13. • N.B.,
▫ Brain is the only tissue in which the breakdown
products of proteins and phospholipids are
extensively reutilized
▫ The retention and reutilization of brain protein
and lipid seems logical in view of the relative
impermeability of the "blood-brain barrier and
the resistance of the brain to deterioration
during long-term starvation.
14. Chemical composition of Myelin:
• Myelin is a lipid-rich structure formed of lipids and proteins
▫Lipids:
–Cholesterol,
–Phospholipids (phosphatidyl ethanolamine, plasmalogens,
phosphatidylcholine, phosphatidylserine, sphingomyelin &
phosphatidylinositol)
–Galactolipids (cerebrosides, sulphatides & ganglioisides)
–Myelin contains very high levels of cholesterol &
galactocerebrosides
–The major fatty acid associated with these complex lipids
is the mono-unsaturated oleic acid, with
polyunsaturated fatty acids being poorly represented
15. Chemical composition of Myelin (cont.):
▫Proteins:
–2 major myelin proteins in the CNS:
–Proteolipid protein (PLP) is the major myelin protein in CNS
it is an integral protein of oligodendrocyte plasma membrane
–Myelin basic protein (MBP): it is a peripheral protein of
oligodendrocyte plasma membrane; it contains lysine & arginine
–Both PLP & MBP promote the formation & stabilization of the
multilayered myelin structure
–In the PNS,
–Po (a glycoprotein) is the major myelin protein in PNS
–Myelin basic proteins (with some similarities and differences to
the CNS MBPs). The major MBP is designated P2.
–Both proteins have a similar structural role in maintaining myelin
structure, as in the CNS.
16.
17. • N.B.,
▫ Myelin is a tightly packed structure; the layers of
myelin are held together by protein/lipid and
protein/protein interactions, and any disruption can
lead to demyelination of the membrane
▫ Antibodies directed against MBPs elicit
experimental allergic encephalomyelitis (EAE),
which has become a model system for
understanding multiple sclerosis, a demyelinating
disease.
18. Demyelination:
• The importance of myelin in nerve transmission is
highlighted by the wide variety of demyelinating
diseases, all of which lead to neurological symptoms
• Demyelinating Diseases:
▫ Demylination of CNS
– e.g. multiple sclerosis (MS)
▫ Demyelination of PNS
– e.g. Guillain-Barre syndrome (GBS)
▫ Other relatively rare demyelinating diseases
19. • Multiple sclerosis (MS)
▫ MS is believed to result from a bacterial or viral
infection that triggers the formation of
autoimmune antibodies directed against
components of the nervous system leading to
antibody-mediated demyelination
▫ Clinical presentation of MS varies from a mild
disease to a rapidly progressive and fatal disease;
but, the most well-known presentation is the
relapsing-remitting type.
20. •Multiple sclerosis (MS) (cont,)
▫The primary injury to the CNS in MS is the loss of myelin
in the white matter, which interferes with nerve
conduction along the demyelinated area (the insulator is
lost)
▫The CNS compensates by stimulating the oligodendrocyte
to remyelinate the damaged axon, and when this occurs,
remission is achieved.
When it becomes too difficult to remyelinate large areas of
the CNS, the disease progresses
▫Agents that interfere with immune responses succeed in
keeping patients in remission for extended periods.
21. • Guillain-Barre syndrome (GBS)
▫GBS is an acute and progressive neuropathy
believed to result from an autoimmune response
triggered by an illness such as a respiratory or GIT
infection, or by certain vaccines, drugs or even
pregnancy.
• Other relatively rare demyelinating diseases
▫Due to Inherited mutations in Po (the major PNS
myelin protein) or in PLP (the major myelin
protein in the CNS); lead to altered function of
either Po or PLP. This leads to demyelination and
its subsequent clinical manifestations.
22. •Essential role in synaptic plasticity.
•Cholesterol imbalance causes hippocampal neuronal
degeneration.
•Dietary cholesterol increases cholesterol & all
phospholipids synthesis in the hippocampus & cortex
•It is believed that the initial pathophysiologic event
that triggers Alzheimer’s disease (AD) is the change in
the chemistry of soluble amyloid-beta (Aβ) protein
(the most important protein in AD research) due to
chronic modulation of CNS cholesterol.
Functions of Cholesterol in the CNS
23. Alzheimer’s Disease (AD) is Characterized
by Two Abnormalities
1.β Amyloid plaques:
▫ Clumps of insoluble Aβ proteins found in tissue
between nerve cells, along with degenerating
fragments of neurons, and other cells (astrocytes:
explaining astrocytosis seen in AD; glial cells:
explaining the increased incidence of glioma in AD
patients) .
▫ In addition, β amyloid plaques cause oxidative damage
in AD brains by generating free radicals (along with
mitochondrial abnormalities, inflammation, abnormal
antioxidant defense) that play a role in the
pathophysiology of AD.
24. 2.Neurofibrillary tangles:
▫ largely comprising the tau protein (bundles of
twisted filaments found within neurons).
▫ Normally: tau proteins augment the function of
neuronal microtubules. However, if they are
excessively phosphorylated they become
twisted into pairs of helical filaments that collect
in tangles, leading to microtubules
disintegration.
▫ The outcome: collapse of nerve-nerve
communication and finally neuron death.
25. Effects of Some Natural Products on AD
• Nicotinamide/niacinamide (vitamin B3):
▫ Reduce tau protein phosphorylation in AD
patients.
▫ Nicotinamide belongs to a group of compounds
known as: Histone Deacetylase (HDAC) Inhibitors,
that enhance memory.
▫ In rodent models of PD, HD, and ALS, these
compounds have protective effect on CNS.
26. • Curcuminoids in curcumin/turmeric
▫ Stimulate the innate immune system by
increasing the number of macrophages
which clears the β amyloid plaques.
▫ Anti-inflammatory & antioxidant properties
exert the following effects:
– Prevent the development of Aβ plaques in brain.
– Inhibit the formation and extension of Aβ fibrils.
– Destabilization of β amyloid plaques that have
already formed.
– Inhibit neurological proliferation.
27. References:
• Textbook of Biochemistry with clinical correlation 6th ed.
• Harper’s Biochemistry 26th ed.
• Wills’ Biochemical basis of Medicine 3rd ed.
• Koudinova NA, Berezov TT, Koudinova AR. Cholesterol
homeostasis failure: A unifying cause of synaptic degeneration.
Neurobiology of Lipids 3, 7, 2004