INTRODUCTION TO PATHOLOGY ( cell adaptation and 4 aspects of disease.)
Summary
TLDRThis video script from Shine Tech's YouTube channel offers an introduction to pathology, defining it as the scientific study of disease. It outlines the four evolutionary steps of a disease: etiology, pathogenesis, morphologic changes, and functional derangement or clinical significance. The script also delves into cell adaptation, detailing its types—hypertrophy, atrophy, hyperplasia, and metaplasia—exploring their causes and implications in both physiological and pathological contexts. The aim is to provide a foundational understanding of how diseases evolve and how cells adapt or respond to various stimuli.
Takeaways
- 🔬 Pathology is the scientific study of disease, focusing on its causes, mechanisms, and effects on the body.
- 🧬 Disease is defined as an abnormal variation in the structure or function of the body's parts.
- 📈 The evolution of a disease typically involves four steps: etiology, pathogenesis, morphologic changes, and functional derangement or clinical significance.
- 🧐 Etiology refers to the cause or causes of a disease, including primary causes and idiopathic cases where the cause is unknown.
- 🛠 Pathogenesis is the process by which the disease's cause operates to produce pathological and clinical manifestations.
- 🔍 Morphologic changes are structural alterations in cells or tissues that occur as a result of pathogenesis.
- 🔬 Morphologic changes can be gross, visible to the naked eye, or microscopic, requiring a microscope to observe.
- 🏥 Clinical significance pertains to how morphologic changes in organs affect their function and lead to the signs and symptoms of a disease.
- 💊 Cell adaptation is a response to stress, where cells may undergo reversible changes in number, size, phenotype, or function.
- 🌱 There are four types of cell adaptation: hypertrophy (increase in cell size), atrophy (reduction in cell size), hyperplasia (increase in cell number), and metaplasia (change in cell type).
- 🚫 Cell injury can lead to reversible or irreversible changes, with irreversible injury ultimately resulting in cell death through necrosis or apoptosis.
Q & A
What is pathology?
-Pathology is the scientific study of disease, focusing on the causes, mechanisms, and effects of diseases on the body's structure and function.
What are the four evolutionary steps of a disease?
-The four evolutionary steps of a disease are etiology (the cause), pathogenesis (the mechanisms through which the cause operates), morphologic changes (structural alterations in cells or tissues), and functional derangement or clinical significance (the clinical features or symptoms of the disease).
What is the difference between primary etiology and idiopathic disease?
-Primary etiology refers to diseases where the cause is known, while idiopathic diseases are those where the cause remains unknown.
What is the term used to describe the period from exposure to a disease-causing agent to the first manifestation of signs and symptoms?
-This period is known as the incubation period or latent stage.
How are morphologic changes categorized in the context of disease?
-Morphologic changes can be categorized as gross morphologic changes, which are visible to the naked eye, and microscopic morphologic changes, which require a microscope to observe.
What is cell adaptation and why is it important?
-Cell adaptation refers to reversible changes in the number, size, phenotype, metabolic activity, or function of cells in response to changes in their environment. It is important because it represents the cell's initial response to stress, which can prevent cell injury or death if successful.
What are the four types of cell adaptation mentioned in the script?
-The four types of cell adaptation are hypertrophy (increase in cell size), atrophy (reduction in cell size), hyperplasia (increase in the number of cells), and metaplasia (a change in cell type).
What causes atrophy in cells?
-Atrophy can be caused by decreased workload or disuse, denervation, diminished blood supply, inadequate nutrition, loss of endocrine stimulation, and aging.
How does hypertrophy differ from hyperplasia?
-Hypertrophy involves an increase in the size of cells, often without the formation of new cells, resulting in an increase in the size of the organ. Hyperplasia, on the other hand, involves an increase in the number of cells, often due to increased cell proliferation.
What is metaplasia and how does it occur?
-Metaplasia is a type of cellular adaptation where one adult cell type is replaced by another adult cell type, usually in response to a particular stress. It occurs through the reprogramming of stem cells to differentiate along a new pathway, rather than a phenotypic change of already differentiated cells.
Can you provide an example of physiological hyperplasia?
-An example of physiological hyperplasia is the proliferation of glandular epithelium in the female breast during puberty and pregnancy, which is stimulated by hormones.
Outlines
🔬 Introduction to Pathology and Disease Evolution
The video begins with an introduction to pathology, defined as the scientific study of disease. It explains that a disease is an abnormal variation in the body's structure or function. The script outlines the four evolutionary steps of a disease: etiology (the cause), pathogenesis (mechanisms of disease), morphologic changes (structural alterations in cells or tissues), and functional derangement or clinical significance (the clinical manifestations or symptoms). The video promises to explore these steps in detail, starting with etiology and moving through to the causes of cell injury.
🧬 Etiology and Pathogenesis in Disease Development
This paragraph delves deeper into the concept of etiology, which refers to the causes and contributing factors of a disease, and distinguishes between primary etiology and idiopathic cases. It then transitions to pathogenesis, which describes the processes through which the disease's cause leads to pathological and clinical manifestations. The discussion includes the concepts of the incubation period and the latent stage, emphasizing the progression from etiology to pathogenesis and the resulting morphologic changes in cells and tissues.
📚 Morphologic Changes and Clinical Significance
The script continues by detailing morphologic changes, which are structural alterations following pathogenesis and can be either gross or microscopic. It explains that these changes impact the organ's function and lead to clinical features, which are the signs and symptoms of a disease. The paragraph also touches on the causes, prognosis, and the importance of understanding the morphological changes in determining the clinical significance of a disease.
🛠 Cell Adaptation Mechanisms in Response to Stress
The focus shifts to cell adaptation, which is the cell's response to stress through reversible changes in number, size, phenotype, metabolic activity, or function. The video outlines four types of cell adaptation: hypertrophy, atrophy, hyperplasia, and metaplasia. It emphasizes that adaptation is the cell's initial response to stress, which can either be successful or lead to reversible or irreversible injury, ultimately resulting in cell death.
🏗️ Types of Cellular Adaptation: Hypertrophy and Atrophy
This section discusses two types of cellular adaptation: hypertrophy, an increase in cell size leading to organ enlargement, and atrophy, a reduction in cell size due to loss of substance. It explains the causes of atrophy, such as decreased workload, denervation, diminished blood supply, inadequate nutrition, loss of endocrine stimulation, and aging. Hypertrophy is presented as the opposite, occurring when cells have a limited capacity to divide and can be either physiological, as seen in athletes, or pathological, as in cardiac enlargement due to hypertension.
🌱 Hyperplasia and Metaplasia: Cellular Adaptation Responses
The video script describes hyperplasia as an increase in the number of cells within an organ due to proliferation, which can be physiological, such as in the female breast during puberty and pregnancy, or pathological, such as endometrial hyperplasia. It also introduces metaplasia, a change where one adult cell type is replaced by another in response to stress, and explains that this adaptation arises from the reprogramming of stem cells rather than a change in already differentiated cells.
🔄 Metaplasia: Adaptation Through Cell Type Replacement
The final paragraph focuses on metaplasia as a type of cellular adaptation where a sensitive cell type is replaced by another that can better withstand adverse conditions. It distinguishes between connective tissue metaplasia, seen in muscle tissue with calcium accumulation, and epithelial metaplasia, which occurs in habitual smokers where normal columnar epithelial cells are replaced by stratified squamous epithelium to adapt to the stress of smoke inhalation.
Mindmap
Keywords
💡Pathology
💡Disease
💡Etiology
💡Pathogenesis
💡Morphologic Changes
💡Functional Derangement
💡Cell Adaptation
💡Hypertrophy
💡Atrophy
💡Hyperplasia
💡Metaplasia
Highlights
Pathology is defined as the scientific study of disease.
A disease is an abnormal variation in the structure or function of the body.
Diseases evolve through four steps: etiology, pathogenesis, morphologic change, and functional derangement or clinical significance.
Etiology refers to the cause or causes of a disease, with known causes termed primary etiology and unknown causes termed idiopathic.
Pathogenesis involves the mechanisms through which the cause of a disease operates to produce pathological and clinical manifestations.
Morphologic changes are structural alterations in cells or tissues following pathogenesis.
Morphologic changes can be gross or microscopic, observable with the naked eye or requiring a microscope.
Functional derangement or clinical significance refers to the impact of morphological changes on the normal function of an organ and the resulting clinical features.
Causes of disease can include trauma, toxins, infections, immunological abnormalities, and genetic abnormalities.
Cell adaptation is a reversible change in response to environmental changes, including hypertrophy, atrophy, hyperplasia, and metaplasia.
Hypertrophy is an increase in cell size, resulting in an increase in the size of the organ, and can be physiological or pathological.
Atrophy is the shrinkage of cells due to the loss of cell substance, leading to reduced function but not cell death.
Hyperplasia is an increase in the number of cells in an organ, which can be physiological, such as hormonal hyperplasia, or pathological.
Metaplasia involves a change in one adult cell type being replaced by another adult cell type to withstand adverse environments.
Connective tissue metaplasia can occur in mesenchymal cells, leading to bone formation in soft tissues due to calcium accumulation.
Epithelial metaplasia is observed in habitual smokers, where normal columnar epithelial cells are replaced by stratified squamous epithelium to adapt to smoke exposure.
The video concludes with a summary of the steps in the evolution of disease and the types of cell adaptation.
Transcripts
hello there welcome to shine Tech's
YouTube channel in this video we're
going to look at introduction to
pathology so in this video we're going
to Define what pathology is then from
there we're going to look at the steps
in the evolution of disease and then
from there we're also going to look at
cell injury cell death
adaptation and cell adaptation then from
there we're going to finally look at the
causes of the of cell injury so to begin
with let's define what pathology is so
pathology is simply the study a
scientific study of disease scientific
study
of of disease so in pathology we study
diseases so what is a disease a disease
is simply an abnormal variation in
structure or function of any part of the
body so if you there is an abnormal
variation in the function or structure
of any part of the body that is called a
disease and a disease will take four
evolutionary steps so these are the
steps the evolutional steps in a disease
so the first step is iology and then
from there the disease will is going to
progress to
pathogenesis after pathogenesis we have
morphologic change and then from there
we have a functional dment or clinical
significance so these are the
evolutional steps
in in a of a disease okay so I'm going
to look at these steps one by one in
detail so these are the four aspects of
the disease Okay so
let's start by looking at etiology so
the term iology simply refers to the
cause or the
causes and mod and modifying factors
which are responsible for the initiation
and progression of a disease so when you
look at this term iology what should
come into your mind is the cause of a
disease so iology is simply the cause of
a disease and if the cause of that
disease is known that is referred to as
primary iology and if it is not known
then we say it is idop idop idiophatic
okay so that is about theology then from
the cause of the disease we move on to
what we call pathogenesis okay so
pathogenesis is simply the
mechanisms through which the cause
operates to produce to produce
pathological and clinical
manifestation okay so the mechanisms the
processes through which the cause okay
through which the iology operates to
produce pathological and clinical
manifestation is what we call
pathogenesis of a disease so and this
pathogenesis could take place in Latin
stage or incubation period which is the
period from exposure to the first
manifestation of signs and symptoms that
is Inc incubation period and the latent
stages from exposure to
B to subclinical to subclinical Onset
that is what we call lent stage okay
then from there the from pathogenesis we
are going to progress
to what we call morphologic changes okay
so I've looked at etiology I've looked
at pathogenesis which is the mechanisms
through which now the cause operates to
produce what we call to produce clinical
features or clinical manifestations
which are the signs and symptoms now
those mechanisms are what we call
pathogenesis so so after
penesis we're going to proceed to
morphologic changes so morphologic
changes these are structure
alterations in cells or tissues so it
can be in
cells or in tissues that occurs
following pathogenesis okay so we have
the cause then that cause causes what we
call theology will progress to progress
to pathogenesis where the mechanisms
takes place
now those mechanisms are going to cause
alterations in the cells or tissues okay
now those alterations that are which
occurs following pathogenesis are what
we call morphologic changes and these
morphologic changes they can be gross
morphologic changes or microscopic
morphologic changes so those morphologic
changes which we are able to see with
our naked eyes are what we call G
morphologic changes and those ones which
require the a of a microscope to for us
to see the changes which has occurred in
cells or tissues then those are called
microscopic changes so from morphologic
changes we move on now to the last uh
evolutional step of a disease which is
functional derangement and clinical
significance so here now we have um the
morphological changes in the organ will
now influence the normal function of the
organ okay the morphologic changes in
the organ influence the normal function
of the organ and determines the clinical
features so from the morphological
changes we have alterations in the cells
and tissues now those alterations will
bring about what we call clinical
features which are the
and symptoms of a disease okay and then
from there clinical features also have a
cause and prognosis of the disease okay
so those were the four uh aspects of a
disease or we can call them the steps in
the evolution of disease which are the
uh
iology
uh we have iology and then we have our
pathogenesis morphologic changes which
are of two type gross morphology
morphologic change and we also have
microscopic morphologic change and then
from there the last one is the
functional derangement or clinical
significance which are the signs in
symptoms now the disease has developed
okay then uh let's also look at um uh
the next part which is cell injury cell
death and adaptation but before we look
at this let's summarize the last part
where we say uh we talk we have talked
about the evolution or steps of a
disease which are the
iology first one is iology so iology or
the cause of the disease a disease can
be caused by a lot of things and one of
them is uh
trauma okay trauma can cause can be a
cause of a disease and then have toxin
toxin
which are which can come from chemicals
or from microbes then from there we have
infections we have immunological
abnomalities those are some of the
environmental causes of disease and then
from there we have genetic abnormalities
all those are going to lead to what we
call iology and from iology we're going
to progress
to pathogenesis which involves the
mechanism of the disease what happens
after that that cause has been
introduced in the body What mechanisms
takes place is what we call
pathogenesis then after pathogenesis
pathogenesis which are the mechanisms
are going to cause um alteration they
going to cause changes in the tissues
and cells okay so those changes are what
we call morphological changes or
morphologic abnormalities then these
morphological changes are now going to
lead to what we call clinical manifest
vations which are the signs and symptoms
so in a nutshell that is all about the
steps in the evolution of disease or we
can call them them the four aspects of
the disease so let's now move on to cell
injury cell death and adaptation but
mainly we're going to focus on Cell
adaptation in this
video okay so we have a normal cell in
the body okay so that normal cell if um
subjected to a stress that cell is going
to adapt to that uh situation to that
environment okay there is a stress which
is stressing the cell then that cell
first of all it will adapt to that
situation okay let's say there is a
chemical which has been ingested or a
drug okay so the cell will try to adapt
to the environment and then from there
if it fails to adapt then it is going to
have a reversible injury okay so if that
uh stimulus is injurious then uh the
cell will be reversibly injured meaning
this injury can be uh this cell can be
reversed to the normal situation the
normal way or the normal the cell can
revers to its normal
uh functions then from there if um the
injury is severe then the cell is going
to uh be irreversibly injured okay so if
it is irreversibly injured that cell
can't be revered to its normal way or it
normal function then eventually that
cell is going to die okay so that will
lead to cell death so a cell can die in
in two ways which is by necrosis or by
apoptosis okay yeah so but in this video
our main focus is cell
adaptation of which if a cell is
stressed the first thing will be to
adapt to that situation okay and then
cell adaptation is of four types we have
hypertrophy atrophy hyper plasure and
meta pleasure so these are the four
types of cell
adaptation okay so what is cell
adaptation so cell adaptation these are
reversible changes in the number okay so
it can be in the number size
phenotype metabolic activity or function
of cells in response to changes in their
environment okay so a cell will try to
adapt in several ways either by Chang in
the number in the size the phenotype or
metabolic activities or even a function
okay so the changes in the function size
number and phenotype U of cells in
response to changes in their environment
is referred to as cellular adaptation
and as I have already said it is of four
types cell will try to adapt via
hypertrophy atrophy hyper pleasure and
meta pleasure so now let's now look at
what really are these types of
adaptation are like hypertrophy what is
hypertrophy what happens and what are
some of the changes the cells undergo in
hypertrophy atrophy hyper plasure and
meta plure so let's now start by looking
at atrophy first as a type of adaptation
so under atropy trophy the cell will try
to uh shrink uh this is
simply shrinkage in the cell in the size
of cells by the loss of cell substance
first of
all this trophy is simply simply means
growth and this a means uh reduced okay
reduced so atrophy simply reduced in the
growth of cell substance okay so the
cell this is simply shrinkage in the
size of cells by the loss of cell
substance that is atrophy or in other
words you can just say reduced in the
size of the cell is atrophy then from
there atrophic
cells may just have diminished function
but they are not dead Okay atrophic
cells are not not de they may just have
diminished reduced functions okay but
they are not de but now what are the
causes of atrophy reduced in the cell
substance reduction in the cell
substance what might cause that okay so
some of the
causes uh here we have decreased
workload or disuse okay so if the cell
is not used it is going to reduce in
size it is going to be at
okay
reduced or decreased workload like for
example if um if the heart overworks
what will happen is that the myocardial
tissue is going to increase that is
hypertrophy so it is going to increase
but in some other parts if the cells are
not used then they are going to undergo
they're going to be atrophied they're
going to reduce in size then from there
the other cause is
denervation denervation okay loss of
innovation to the cell can cause atrophy
then we also have diminished blood
supply we know that blood supplies
nutrients and oxygen to tissues now if
that Supply is reduced automatically the
cell is going to be atrophied then the
other thing is inadequate nutrition
inadequate nutrition you do not have
adequate nutrients for the cell to
increase in size so the cell will be
atrophied then loss of endocrine
stimulation okay that cell is no longer
stimulated then it is going to atropy
then aging which is s now atrophy in old
age mostly cells will undergo or be
atrophied so those are some of the
causes of atrophy then from there we
have what we call hypertrophy
okay so hypertrophy hyper that is
increased then trophy we say it is
growth so increased in the growth okay
so hypertrophy is an
increase okay an increase in the what in
the size of cells resulting in an
increase in the size of the organ so we
have an increase in cell size meaning
hypertrophy simply
the opposite of atrophy in atrophy we
had reduction in cell grow and then here
we have an
increased uh growth in the cell okay
then there are no new cells which are
formed in pure hypertrophy in pure
hypertrophy we do not have new cells
which are formed okay just larger cell
containing okay larger just larger cells
okay the cells will just increase in
size then they are going to contain
increased amount of structural proteins
and organel okay so the organel are
going to increase in size and then the
structure proteins are also going to
increase okay so hypertrophy occurs when
cells have a limited capacity to divide
okay most organs which have
limited capacity of cells to divide
that's where mostly hypertrophy takes
place okay so hypertrophy can be
physiological or pathological so under
physiological uh hypertrophy we have um
like for example skeletal muscle tissue
in body builders okay so skeletal muscle
in body builders we becomes hyper
hypertrophied like they increase in the
in size as we are able to view few
muscles of a body builder so that is an
example of a physiological it's a normal
normal thing it's not an abnormal so
when you talk about physiological
meaning it's a normal uh thing okay so
skto muscle tissue in body builders is
simply an example of physiological
hypertrophy now pathological hypertrophy
here we talking about abnormalities
something which is not normal so we can
see phys logical hypertrophy in cardiac
enlargement in hypertension or iotic
valve diseases okay so in um
cardiac
hypertension we have an
increased uh blood pressure okay so the
heart is overworking so due to
overworking the mardum is going to
increase in size it is going to become
hypertrophy okay th is going to increase
in size and then in iotic valve disease
there is um stenosis of of the valve
there from
the uh left ventricle to the Iota we
have what we call the iotic valve there
so if this valve is not functioning
properly okay then the heart you have to
pump blood with
um High pressure so that that blood can
flow in that valve in that defected
valve so to do so it is has
to to increase its muscle tissue okay it
stried muscle tissue has to increase in
size so so that it overcomes this
obstacle which is on the way which which
is called iotic Val disease itic valves
tenoc okay the valves have become
rigid so they are not functioning
properly so the heart has to pump blood
with strength so that will cause the
cells of the heart to be
hypertrophied okay to increase in size
to overcome that obstacle that
derangement which has occurred there so
we can see pathological hypertrophy in
Artic valve diseases and also in cardiac
enlargement in
hypertension okay so that's all about
hypertrophy now let's move on to what we
call hyper pleasure so hyper also we are
talking about the increase then pleasure
is simply number so here we're talking
about the increase in the number of
cells so an increase in the number of
cells in an
organ okay in an organ that stems from
from increased proliferation so this
this increase should come from
proliferation okay where we have cells
which are dividing and then the number
of cells increases that is what we call
hyperplasia and it can also be
physiological or pathological so
physiological hyperplasia here we are
talking about
proliferation okay normal proliferation
of cells like for example pration of
glandular Epi of the female breast at
puberty and during pregnancy we normally
see breast being enlarged that is an
example of
physiological hyperplasia the increase
in number of granular cells in the
breast of a female that is an example of
physiologic go hyperplasia and that is
called hormonal hyperplasia why because
it is stimulated by hormones okay there
are hormones which are responsible for
stimulation of these cells to undergo
what we call hyperplasia that is
hormonal hyperplasia and then we also
have uh another example where we have
res residual tissue growth after removal
or loss of part of an organ a good
example here is the liver so if the
liver is damaged or you cut the piece of
the liver is going to to grow back it is
going to grow and uh uh and be be go
back to its normal it normal structure
so that is what we call compensatory
hyperplasia so hyperplasia is of two
type have hormonal hyperplasia and
composor Hyper pressure and
physiological hyper pressure then from
there hyper pressure can also be
pathologic okay can also be pathologic
and examples of pathologic hyper plasure
here we talking about endometrial
hyperplasia okay endometrial hyperplasia
which is the lining of the uterus which
we call the
endometrium increases in uh the number
of cells there increases after the
mation period there in females the
endometrium is going to increase the
cells there are going to increase and
that is what we call endometrial
hyperplasia but now if this thing is uh
abnormal
if we have abnormal production of
ovarian estrogen and separation of
progesteron what will happen is that the
number of cells in the endometrial is
going to increase it's going to be
excessive why because we have excessive
stimulation of release of estrogen and
that is going to cause what we call
endometrial hyperplasia and then we are
going to see
bleeding okay we going to see vinal
bleeding that is now what we call indom
material hyper plas and it can lead to
cancer okay then from there apart from
indom Material pleasure this
pathological hyperplasia can also be
seen in benign Pro prostatic hyperplasia
in males this is caused by androgens
over production of androgens is going to
cause benign Pro
protic hyper plure so these are the
examples of pathologic hyper plure then
from hyper plasure we have what we call
metaplasia as a type of cellular
adaptation okay so metaplasia met
pleasure is simply a change in which one
adult cell type okay it can be epia or
methos cells okay so we have a change in
one adult cell
type is replaced by another adult cell
type okay so we have uh cell type which
is being replaced by an another type of
another adult cell type here okay so now
this type of cellular
adaptation in this type of cell
adaptation a cell type which is
sensitive to a particular stress okay so
a cell type which is sensitive to a
particular stress is going to be
replaced by another cell type which is
better able to
withstand adverse environment so we have
a stress okay a stress which is being
applied on a sensitive cell type so that
sensitive cell type is going to be
replaced by another cell type which will
be able to with stand okay that adverse
uh environment then that is what we call
Meta
pleasure okay so it
arises okay it arises by
reprogramming of stem cells to
differentiate along a new pathway rather
than a phenotypic change of already
differentiated cells so here we have
reprogramming of stem cells are being
reprogrammed to produce a new
pathway okay new types of cells
reprogramming of these stem cells to
produce new types of
cells not from uh not from
already differentiated cells okay but
from the stem
cells the stem cells are going to uh to
differentiate to replace the already
differentiated cells that's how this uh
mechanism of metapure takes place then
we have it is of two types we have what
we call connective tissue metap pleasure
have connective tissue metap pleasure
which occurs in mesos cells where we
have have uh bone occasionally formed in
soft tissues due to accumulation of
calcium this is mainly seen in muscle
tissue where if we have accumulation of
calcium then we are going to see uh bone
formation in that tissue in those selfy
tissues due to accumulation of calcium
then the other type is Epal metaplasia
so we have connective tissue metaplasia
and EP eal metapure so Epal
metapure this one occurs in habitual
cigarette smokers those who are
frequently smoke okay where the normal
cated colum epia cells of the tracha and
broni are often replaced by stratified
squ ethereum so have a sensitive tissue
type which is
cated Colum
Epal cell which is being replaced by
another Epal cell type which is
stratified squ Mass eperium this is done
to adapt to the current situation or to
the environment in uh where now we have
smoke okay okay in cigarette smokers we
have a stress okay as in form of smoke
so this sensitive serated colia is going
now to be repaced the stem cells are
going to form new cells which are
stratified SOS eperium to replace the
cated col etherum and that is
a that is what we call ethereal meta
pleasure so thank you very much for
watching don't forget to like And
subscribe and leave your comment in the
comment section see you in the next
video where we're going to talk about
cell injury and uh cell cell
death
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