Red White Blood Drsadiah

7/29/2019 Red White Blood Drsadiah

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RED AND WHITE BLOOD CELLS

WBC (leucocytes) : Granulocytes (PMN) neutrophils

basophils

eosinophils

Monocytes macrophage

Lymphocytes L.B. antibodies

L.T. cellular immune

mechanism


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Neutrophils : - phagocytose bacteria

- role in acute inflammation

Basophils : - contain histamin & heparin

- role in immunologic hypersensitivity reactions

Eosinophils : - allergic reactions

- parasitic infectionsMonocytes : - precursor of macrophages

- phagocytosis

Lymphocytes : role in chronic inflammation

Neutrophils & lymphocytes : quantitatively major classes in

normal blood


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RBC (Erythrocytes)

Function : delivering O2 from lung to the tissue and helping

disposal of CO2 & proton from the tissueStructure : - simple, composed of concentrated solution of Hb

(95% of intracell protein) surrounded by a mem-

brane

- no intracellular organelles

- non nucleated

- biconcave shape (discoid) increase surface-

volume ratio fascilitating gas exchange- contains cytoskeletal components determine

shape


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RBC count: - men : 4.6 - 6.2 million / L ~ 14 18 g/dL Hb

- women: 4.2 - 5.4 million / L ~ 12 16 g/dL Hb

Total number in circulation : 2.5 x 1013

Hematocrit (packed cell volume / PCV) : - men : 42 - 52%

- women : 37 - 47%

Life span : 120 days

Reticulocytes ( 1% of total RBC count ) :

- contain ribosome & endoplasmic reticulum active in protein

synthesis.

- in hemolytic anemias : - life span RBC : shortened

- reticulocytes


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* Production of RBC (erythropoiesis) is regulated by erythro-

poietin

H erythropoietin : - glycoprotein of 166 A.A (34 kDa)

- synthesized by kidney, released inresponse to hypoxia to the bone

marrow : interacts with RBC progenitor :

(via specific receptor)

1. Burst -forming unit erythroid (BFU E) proliferate &differentiate

2. Colony-forming unit erythroid (CFU E) proliferate

& differentiate

Requires the cooperation of IL-3, insulin like growth factor

cDNA encoding erythrop. recombinant erythrop. : treatment

of anemia due to renal failure


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* Production of WBC is regulated by :

hematopoietic growth factors :

- glycoprotein

- specific cell surface receptor on target cells via intra

cell signals gene expression promoting differentiation

1. Granulocyte colony stimulating factor ( G-CSF) :

specific, inducing granulocytes

2. Granulocyte-macrophage col. stim. F (GM-CSF) :

affects variety of progenitor cells induces granulocytes,

macrophages & eosinophils

Neutropenia : - production of neutrophils is depressed

- in patients treated with chemotherapeutic /

after bone marrow transplantation develop

infections

G - CSF is useful


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METABOLISM OF RBC

Glycolysis

GlucosePentose-P pathway NADPH

* Glycolysis: - lactate

- ATP

- 2,3 Bis-P glycerate (BPG/DPG)

- NADH

1. ATP: - maintain biconcave shape

- regulation of ion transport :- Na+ - K+- ATPase. Ca2+-ATPase

- anion exchange protein

- water in and out of the cell


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2. 2,3 BPG: modulating O2 affinity of Hb

Glycolysis1,3 Bis-P-glycerate Glucose

ADP B-P-glyceratemutase

2,3 Bis-P-glycerateATP

Pi

3-P-glycerate 2,3 Bis-P-glyceratephosphatase

Pyruvate


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3. NADH:

RBC posses a system:

NADH-cytochrome b5 met Hb-reductase system reduced

Fe3+ Fe2+

Hb Fe3+ Cyt.b5 red NAD

Met Hb

Hb Fe2+ Cyt.b5 ox NADH

Cyt b5 reductase(met Hb reductase)


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* PPP NADPH, catalyzed by glucose 6-P dehydrogenase

. (G6PD)

Function of NADPH : reduced GSSG GSH

GSSG GSH

glutathion reductase

NADPH + H+ NADP+

G-SH: counteract the action of toxic peroxides protect RBC

from oxidative damage


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* Entry of glucose into RBC : facilitated diffusion by means

of glucose transporter (glucose permease) : GLUT I :

- 2% of protein RBC membrane

- specific for D glucose & related D hexose

- affinity for D glucose is highest

- inhibited by glucose analog (phloretin)

- not insulin dependent

- contain 12 transmembrane (hydrophobic) helical

segment

- function by generating a gated pore in the

membrane ( conformationally dependent on the

presence of glucose)


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During metab. RBC generates oxidants oxidative stress

& damage : - superoxide (O2), peroxide (H2O2)

- peroxyl radicals : ROO*

- hydroxyl radicals : OH* (reactive), react with

proteins, nucleic acid, lipids & other mol alter

structure

tissue damage

RBC contains cytosolic enzymes to protect from oxidative

stress : - superoxide dismutase

- catalase

- glutathion peroxidase (Se)


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* Superoxide (O2

) :

- formed by autooxidation of Hb met Hb (3%)

- dismutates spontan H2O + O2

or by superoxide dismutase:

O2+ O2

+ 2H+ H2O2 + O2

* H2O2 : - catalase H2O2 H2O + O2

- myeloperoxidase : H2O2 + X+ H+ HOX + H2O

(neutrophils) X = Cl,Br, SCN

- glutathion peroxidase : H2O2 + 2G - SH GSSG +

2H2O

R-O-O-H + 2GSH GSSG + H2O+ ROH


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* OH* & OH

: formed from H2O2:

- nonenzymatic (Fenton reaction), catalyzed by Fe2+

Fe2+ + H2O2 Fe3+ + OH* + OH

- Iron catalyzed (Haber-Weiss reaction)

O2+H2O2 O2 + OH* + OH

O2 released Fe ions from ferritin production of OH*

mechanism of tissue injury due to iron overload


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* Pro oxidants : compounds & reactions capable of

generating toxic oxygen species

* Anti-oxidants : compounds & reactions disposing toxic

oxygen species, scavenging, suppressing their formation or

opposing their actions (include : NADPH, GSH, vit C, vit E)

Normal : appropriate pro-oxidant-antioxidant balance

Shifted toward pro-oxidant :- production of oxygen species (chemicals, drugs)

- antioxidants level (inactivation of enzymes)

oxidative stress cell damage


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* Def. G6PD (mutation: > 300 genetic variants) hemolytic. An.

- consumpsion of beans : Vicia faba (contains oxidants)

- drugs : sulfonamides, primaquine

- chemicals : naphthalene

generation of H2O2 or O2-

Normal : H2O2 is disposed by catalase & glutathion peroxidase

( GSSG)

* RBC with def.G6PD : cannot regenerate GSH

impair the ability to dispose H2

O2

& O2

radicals

- oxidation ofSH groups in protein

- peroxidation of lipid membranes lysis of RBC membr.

- oxidation of-SH group of Hb precipitates inside RBC

Heinz Bodies


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* Fe2+ of Hb is susceptible to oxidation by superoxide met Hb

Normal blood: very small amount of met Hb

* Methemoglobinemia : - inherited

- acquired : ingestion of certain drugs

(sulfonamides), chemicals (aniline)

Inherited : - def. Met Hb reductase:

- abnormal Hb (Hb M) : mutation changes A.A

residue to which heme is attached altering affinity

for O2 favoring oxidation

* Cyanosis : bluish discoloration of skin & mucous membrane

- deoxy Hb in arterial blood

- met. Hb (>10%)Treatment : - mild met Hb (def.enz) : ingest methylene blue or

ascorbic acid ( reducing agents)

- acute massive met Hb (ingest chemicals)

methylene blue I.V.


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The membrane is a bilayer composed of about 50% lipid and

50% protein.

The major lipid classes are phospholipids and cholesterol; the

major phospholipids are phosphatidylcholine (PC), phospha-

tidylethanolamine(PE), and phosphatidylserine (PS) along

with sphingomyelin (Sph). The choline-containing phospholipids, PC and Sph, pre-

dominate in the outer leaflet and the amino-containing

phospholipid (PE and PS) in the inner leaflet.

Glycosphingolipids (GSLs) (neutral GSLs, gangliosides, and

complex species, including the ABO blood group substances)

constitute about 5 10% of the total lipid.

Membrane of RBC


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Analysis by SDS PAGE shows that the membrane contains

about 10 major proteins and more than 100 minor species.

The major proteins (which include spectrin, ankyrin, the anion

exchange protein, actin, and band 4.1) have been studied

intensively, and the principal features of their disposition

(eg, integral or peripheral ), structure and function have

been established.

Many of the proteins are glycoproteins (eg, the glycophorins)

containing O or N linked (or both) oligosaccharide chains

located on the external surface of the membrane.

Membrane of RBC


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Major Proteins of The Membrane of Human RBC

Skeleton

Coomassie Blue stain

Membrane

PAS stain

Glycophorins

Actin

G3PD

Globin

Anion exchange

protein

1

22.12.22.32.6

Spectrin

Ankyrinand

Isoforms

Membrane

5

6

7

3

4.14.2


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Membrane of RBC

* SDS - page analysis : 10 major proteins

some are glycoproteins : staining with periodic acid schiff (PAS)

* Sensitive staining methods or two-dimensional gel electro-phoresis : minor components (glucose transporter)

Integral membrane proteins:

* Anion exchange protein :

- transmembr. glycoprot C term. : on external surface

N term. : on cytosolic surface

- multipass membrane protein

- dimer forms tunnel exchange Cl- for HCO3-

- N-term. binds many proteins : Hb, Pr.4.1, 4.2, ankyrin &

several glycolytic enzymes.


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* Glycophorins A, B, & C : - transmembrane glycoprot

- single pass

Glycoph. A :

- 131 A.A., 60% is glycosylated

- N-term. contains 16 oligosach. chains, extrudes out from

the surface

- contains sialic acid (90% of sialic acid of RBCmembrane)

- transmembrane segment (23 A.A), helical

- C-term. extrudes into cytosol, binds Pr.4.1 - spectrin

- polymorphism MN blood group system

- contains binding sites for influenza virus & plasmodium

falciparum

Peripheral membrane proteins


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Peripheral membrane proteins

- peripheral cytoskeletal protein

- attached to the inner membrane

- preserving shape & flexibility of membrane* Spectrin :

- 2 polypeptides : - spectrin 1 ( -chain)

- spectrin 2 ( -chain)

- 100 nm length, anti paralel

- loosely intertwined dimer

- one dimer interact with another head-to-head tetramer

- 4 binding sites for : - self association- ankyrin

- actin

- Pr.4.1


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*Ankyrin : - pyramid-shaped

- binds spectrin & binds tightly band-3

- sensitive to proteolysis bands: 2.2,2.3,2.6 all

derived from band 2.1

* Actin : - short, double-helical filaments of F-actin

- binds tail end of spectrin dimer & Pr.4.1.

* Protein 4.1: - globular protein

- binds to tail end of spectrin, near actin binding

site Pr.4.1-spectrin-actin complex

- binds to glycophorins A & C

attaching thecomplex to membrane

- interact with membr. P.L connecting lipid bilayer

to cytoskeleton


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* Abnormal spectrin ( amount or structure) hereditary

spherocytosis & elliptocytosis

Hereditary spherocytosis:

- spherocytes in peripheral blood

- hemolytic anemia, splenomegaly

- def.amount or abnormal structure of spectrin no

tightly binds the other proteins weakens the membr.

spherocytic shape

- subject to destruction in spleen

shortening life incirculation , curable by splenectomy


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Hereditary elliptocytosis :

- genetic ~ her. spherocytosis

- elliptic, disk.like shape

- abnormal spectrin

- some cases : abnormal of band 4.1 / glycophorin C


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Blood group system

The surface of RBC : - covered with specific antigenic

determinants

- 100 blood group determinants

21 H blood group system

The best known : - ABO system

- Rhesus (Rh) system

important in blood

transfusion

ABO system


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ABO system

RBC membrane of individuals contain one blood group

substance : type A, type B, type AB, or type OType A : - do not produce antibodies A,

- posses antibodies B agglutinate type B /type AB blood

Type B : anti A antibodies agglutinate type A /type AB blood

Type AB : neither anti A nor anti B antibodies universalrecipient

Type O : neither A nor B substance posses antibodiesto both A & B universal donor

ABO substance


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ABO substance

ABO substance : complex oligosaccharida : glycosphingolipid

H. substance : - precursor of A & B substance

- O blood group substance- specific oligosach formed by the action of

fucosyltransferase which adds fucose to peri-

pheral galactose of its precursor (heterosach.)

* Definite correlation between gene activity - specific glycosyl

transferase synthesis - oligosaccharida structure

H. gene : codes fucosyl transferase

ABO gene : - located on long arm of chromosome 9

- 3 alleles : - A & B : codominant

- O : recessive

4 phenotypic products : A,B, AB, O substance

A gene : encodes N acetyl galactosamine (GalNAc)


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A gene : encodes N-acetyl galactosamine (GalNAc)

trasnferase adds terminal Gal Nac to O substanceB gene : encodes galactosyl transferase : adding gal. residue

to O substance

O gene : encodes inactive enzyme

Type AB posses both enzyme - 2 oligosach. chains :- 1 type A chain, 1 type B chain

* Specificity of ABO blood types is determined by sugars

GalNAc : immuno determinant of blood type A

galactose : immuno determinant of blood type B

Removal of Gal NAc from type A erithrocytes or galactose

from type B erythrocytes convert both type to Oerythrocytes


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Rhesus (Rh) system

* 3 closely linked genes is involved, located on chromosome 1

the products : C or c, E or e, D or d* D (RhO) antigen : - major antigen Rh factor

- integral membr. protein (30 kDa)

- interact with membr. p -lipids antigenicity

* 15% caucasians lack the antigen Rh - negativeA female (Rh - neg) is transfused with Rh. pos. blood and

become pregnant, if her infant is Rh - pos lysis ofinfants erythrocytes ( hemolytic disease of the new born)

ANEMIA


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ANEMIA- Blood contain fewer erythrocytes / decreased Hb content

- Caused by many factors

decreased O2 carrying capacity impaired O2 delivery to the tissue

symptoms : - fatigue- faintness

- headache

- lack of concentration

The causes are varies 3 broad categories :1. Decreased number of RBC due to shortened life span

- abn. Hb : HbS, HbC, thalassemia

- abn. membr. prot.defect cell shape : spherocytosis- abn. enzyme : G6PD def.

- infection : malaria

- immun. desorders : hemolytic disease of the newborn

2. Decreased production of RBC

- impaired Hb synthesis : Fe Def.

- defect in stem cell maturation : Vit. B12 def.

3. Abnormal red cell

The bod has compensator mechanism dela ing the


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The body has compensatory mechanism delaying the

onset of anemia

Impaired O2 delivery

* Increasing 2,3 DPG synthesis modulates O2 affinity of

Hb O2

dissociates more readily at low O2

tension in the

tissues Hb function more efficient

* Releasing erithropoietin accelerates RBC maturation in

bone marrow

* In hemolytic anemia bone marrow produces more cells &

sometimes are released prematurely reticulocytes in

circulation

Hemolytic anemia


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Hemolytic anemia

- Increased rate of RBC destruction

- Jaundice- Hb in urine dark colour (black water fever)

* Inherited hemolytic anemia

1. RBC membr. defects

spherocytosis - spherocytes

- defect in spectrin - actin network

- membr. is leaky to Na+ activity ofNa+- K+- ATP ase demand for

ATP ( high glycolytic rate)


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2. Abnormal Hb : single A.A. substitution in - chain

Hb S sickle cell anemia

Hb C, Hb D, Hb E

decreased solubility in deoxy- form

3. Thalassemia : synthesis of globin chains are depressed

- - thal

- - thal


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4. Abnormal enzyme

- G6Pd def.G6PD gene : on x - chromosome

- all RBC are affected in males & homozygous females

- heterozygous females : part of RBC with full enzyme

activity & the remainder with

no G6PD activity

- Pyruvate kinase def.

- Met Hb reductase def.


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* Acquired Hem. An

- malaria

- bacterium : clostridium welchii

- snake venoms, spider

- mismatched blood transfusion

- hemolytic disease of the newborn

releases P lipase

lysis cell membr.

Neutrophils


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Neutrophils

- active aerobic glycolysis, active PPP

- moderate oxidative phosphorylation

- rich in lysosomal enzymes

- contain : - unique enzyme : - myeloperoxidase (MPO)

- NADPH oxidase

- defensins (20 33 A.A) kill bacteria- lactoferrin (Fe-binding prot.)

inhibit growth of

bacteria

- CD 11a / CD 18, CD 11b / CD 18, CD 11c / CD18

integrins (adhesion molecules)

- receptors Fc fragments of IgG : bind Fcfragments of IgG

Neutrophils : motile phagocytic cells defense againstbacterial infection role in acute inflammation

B t i t ti t i fl t


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Bacteria enter tissues acute inflammatory responseA variety of agents are released from cells & plasma proteins

vascular permeability tissue edema- mast cells & basophils histamin- platelets serotonin- neutrophils platelet activating factor (PAF), eicosanoids

- plasma Pr.

- C3a, C4a, C5a, from complement syst.- bradykinin & fibrin split products

- neutrophils are recruited from blood stream into the

tissue by chemotactic factors (C5a, leukotrienes)

- adhesion of neutrophils to endothel cells is mediated by

integrins & specific receptor in endothel

- neutrophil is activated turn on metabolic processesinvolved in phagocytosis & killing of bacteria


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Integrins : - surface protein

- hetero dimers, contain & subunit

subunit contain : extracell, transmembr. &

intracell segments:

extracell segm. : binds ligands (specific prot. of

extracell matrix / surfaces of other cells

intracell segm. : binds various proteins of

cytoskeleton

link outsides of cells to their insides- involved in adhesion cells to cells or to specific

components of extracell matrix

A ti ti f t hill l t l t ti ti


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Activation of neutrophills ~ platelets activation

- specific receptor

- interaction with - bacteria,

- binding of chemotactic factors

- antibody antigen complexes

Ca2+ intracell - secretion of granules content- motility

ready to destroy bacteria

- rapid increase in O2 consumption (respiratory burst)rapid utilization of O2 produce large amount ofreactive derivates of O2 : O2

, H2O2, OH* & OCl


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- electron transport chain system : NADPH oxidase :

- cytochrome b558 : - in the plasma membr.

- heterodimer : 2 polypeptides

(91 kDa & 22 kDa)

- 2 cytoplasmic polypeptides ( 47 kDa & 67 kDa) :

recruited to plasma membr.

- NADPH : generated by PPP


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O2 formed is discharged to outside of cell or into phago -

lysosomes kill bacteria :combined action of : - pH, O2

, HOCl- defensins, cathepsin G

- certain cationic proteins

O2 H2O2 : spontan or by superoxide dismutaseO2

+ O2 + 2H+ H2O2 + O2

H2O2 MPO HOCl : powerful oxidant, highly microbicidaldisposed of by glut. peroxidase / catalase


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Genetic def. in NADPH oxidase syst.

- recurrent infection

- widespread granulomas in skin, lung & lymph nodes

Some patients respond to treatment with - interferontranscription of 91 kDa component


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Mutations in genes for the polypeptide components

of the NADPH oxidase system

Diminished production of superoxide ion

and other active derivatives of oxygen

Diminished killing of certain bacteria

Recurrent infections and formation of tissuegranulomas in order to wall off surviving bacteria


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Neutrophils contain proteinases (lysosomal enz.)

- elastase, collagenase, gelatinase, cathepsin G

- hydrolyze elastin. collagen & other protein in

extracell matrix tissue damage- inactive in normal neutrophils

- small amount are released into normal tissues &

increasing during inflammation

- the activities are normally controlled by anti -

proteinases in plasma & extracell fluid : forming

complex inhibition


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Antiproteinases : - 1 antitrypsin,

- 2 macroglob,

- 1 anti-chymotrypsin

Genetic def. of1 antitrypsin excessive action of elastase digest pulmonary tissue participate in the cause of

emphysema


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Hemolytic anemia

Causes :1. Outside membrane

- hypersplenisme- immunologic abnormalities (transfusion reactions)

- toxins - certain bacteria (clostridium)

- snakes venoms2. Within the membrane

- abnormalities of protein (her. spherocytosis

& her elliptocytosis)3. Inside RBC

- hemoglobinopathies ( sickle cell anemia)

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Red White Blood Drsadiah