DOCSLIB.ORG

Bilirubin and Jaundice 0-3 Days 40-80 Days

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Bilirubin and Jaundice 0-3 Days 40-80 Days Sources of bilirubin production in the rat Early Bilirubin Late Bilirubin 15% 65% Bilirubin and Jaundice 0-3 Days 40-80 Days Increased Erythropoiesis Red Cell Non- Senescence Hemoglobin Sources (liver) Sources of bilirubin production in the rat, as adduced from studies of the labeling of plasma bilirubin in Gunn rats and bile bilirubin in normal rats. Pathways of Bilirubin Synthesis and Catabolism NADPH NADP Bone Reticuloendothelial Hemin + Marrow RBCs System (RES) N N Hgb Hgb Fe Fe OH NADPH O2 Globin Heme Precursors NADP NN Biliverdin Myoglobin Globin N N + Non-Hgb Heme Fe Heme COO COO Proteins NN Bilirubin O2 CO heme-oxygenase complex Fe Fe (II) + COO COO Porphogens Shunt OH HO Free Bilirubin – Albumin Complex Pathway hydroxyheme-oxygenase complex N N OH HO NADPH H Conjugated NADP NH N Urine Bilirubin 68mg 2mg N N Urobilinogen in H Biliverd OOC COO N N reductase 70mg C biliverdin HH Fecal OOC COO Urobilinogen Stercobilin Pigments bilirubin Labeling of RBC hemoglobin and fecal stercobilin 0.3 N of haemin N N of stercobilin of N 15 15 B 0.1 0.2 X X 0.08 X X 0.06 X 0.1 X 0.04 A X X X X X X 0.02 X X X B: Atomexcess % A: Atomexcess % 20 40 60 80 100 120 140 160 180 Times ( days) Labeling of red cell hemoglobin and fecal stercobilin in a normal human given 15N orally 1 BILIRUBIN CONJUGATION IN MICROSOMES INVOLVES TWO STEPS, MEDIATED BY ONE BILIRUBIN-UDPGA TRANSFERASE BILIRUBINS: C O H UDPGA H O H UNCONJUGATED C N N O (ligandin) (UCB) O N N H O H H 1 O C C O GA UDPGA O UDP MONO- H H TRANSFERASE C N N O UDPGA MDR2 GLUCURONIDE O N N OATP H O H H (BMG) O C 2 C O GA O H H C N N O UDP DIGLUCURONIDE O N N H H (BDG) O Conjugation prevents GA O C internal H-bonding by the -COOH groups of Bilirubin A. OATP MDR2 B. (=cMOAT) CH2 CH Me UROBILINOGENS ARE FORMED BY β CO (excreted via lungs) Me A B CH2 CH2 CO2H DECONJUGATION AND REDUCTION OF NH N α Fe γ Fe (reutilized) N NH BILIRUBINS BY INTESTINAL BACTERIA C CH CH CO H H2C CH D 2 2 2 CO H CO H δ 2 2 Me Me CONJUGATED BILIRUBIN CH2 CH2 CH2 CH2 A UROBILINOGEN Me CH Me CH CH Me 2 2 Me CH COOGA COOGA CH BCDCH COOH COOH A. A CH2 O N N N N O H H H H M M BILIRUBIN – IX α (planar structure) M M N UNCONJUGATED N N H H N BILIRUBIN H H D H H2C CH A N H H H H 2 B. B N N H N V M COOH COOH C E M O O O M V O BILIRUBIN – IX α (convoluted structure) M M M E COOH COOH N N O O Deconju- H H C. OH O O OO HO H Reduction HO C C OH gation N H OH HO CH2 CH CH N CH2 2 2 Me Me CH CH2 CH2 Me Me CH V M CH CH M = Methyl CH2 O O + 8H O N N N N O 2 GA H H H H E = Ethyl M V BILIRUBIN - IX α DIGLUCURONIDE V = Vinyl 2 Bilirubinuria in Jaundice UNCONJUGATED PLASMA BILIRUBIN (B) CONJUGATED P L A S M A (A=ALBUMIN) U R I NO BILIRUBIN N BILIRUBIN ++ E FRACTIONAL DIAZO REACTION OF PLASMA RR SO H 3 Fast Direct + reaction N+ N CONJUGATED BILIRUBIN SO3H DIAZO REAGENT Slow Indirect + reaction N+ N UNCONJUGATED BILIRUBIN TOTAL DIAZO REACTION OF PLASMA RR CONJUGATED SO3H BILIRUBIN + + ACCELERATOR N+ (ALCOHOL, CAFFEINE) N UNCONJUGATED BILIRUBIN TOTAL – DIRECT = INDIRECT 3 Phototherapy for neonatal jaundice h p Sn-PP Liver Co-PP Liver g m / 2.5 16 n i b u r i l i 2.0 b l 12 o m n ( 1.5 e s 8 a n e 1.0 g y x O 4 e 0.5 m e H 0 8 16 24 0 2 4 6 8 10 (hours) (days) Time Effect of Sn-protoporphyrin (Sn-PP) and CO-protoporphyrin (Co-PP) when administered once at a dose of 50 μmol/kg body wt on hepatic heme oxygenase activity in the rat. Bile-Duct RAT PBC Treatment for Neonatal Jaundice Sn-PP 10.0 Ligation (50 ) 18 Prevention of kernicterus Control 7.5 16 14 5.0 Sn-PP 12 Plasma Bilirubin mg/dl Bilirubin Plasma 2.5 10 -40 2 4 012 34567 Time (days) Effect of Sn-protoporphyrin (Sn-PP) (100 μmol/kg body wt) administered at 4d before and on the day of surgery on hyperbilirubinemia in the bile-duct-ligated rat. Effect of Sn-PP (2 x 0.25 μmol/kg body wt) on the levels of serum bilirubin in a patient with primary biliary cirrhosis (PBC). COOH COOH UGT1 gene CH2 CH2 CH2 CH2 5’ 3’ Me CH Me CH2 CH2 Me Me CH CH BCDCH A CH2 O N N N N O H H H H 1J 1I 1H 1G 1F 1E 1D 1C 1B 1A 234 5 mRNA Bilirubin IX α B-UGT1 COOH COOH CH Phenol 2 CH2 CH2 CH2 Me CH2 Me CH2 Me CH Me CH UGTs CH CH CH2 O N N N N O H H H H Bilirubin IX β NH2 COOH substrate binding site UDPGA membrane binding site spanning Structure of the α and β isomers of bilirubin IX. In the IXβ isomer (and in the enzyme region γ and δ isomers, not shown) the propionic acid groups are moved to positions 285 amino acids 246 amino acids other than those indicated on the central pyrrole rings B and C of bilirubin IXα. 4 Unconjugated Hyperbilirubinemia Characteristics Crigler-Najjar Type I Gilbert Syndrome Plasma bilirubin 340-860 μM 50-85 μM (fluctuates) Plasma BSP retention at 45 Normal Usually normal; elevated min in a minority of cases Hepatic bilirubin-UDPGT Undetectable 30-50% of normal activity Effect of Phenobarbital on No effect Reduction plasma bilirubin Pigments in bile Small amounts of unconjugated Increased proportion of bilirubin monoglucuronide Prevalence Rare 2-7% of population Prognosis Kernicterus Benign Animal Model Gunn rat Bolivian Squirrel Monkey Mutation UDPGT null UDPGT promoter A(TA)6TAA Chronic conjugated hyperbilirubinemias Characteristic Dubin-Johnson Syndrome Rotor Syndrome Jaundice Appearance of liver Grossly black Normal Histology of liver Dark pigment; predominantly in Normal centrilobular areas; otherwise normal Serum bilirubin Elevated, usually between 2 and 5 mg%, Elevated, usually between 2 Conjugated bilirubin occasionally as high as 20 mg%; and 5 mg%, occasionally as predominantly direct-reacting high as 20 mg%; Unconjugated bilirubin predominantly direct- reacting Routine liver function Normal except for bilirubin Normal except for bilirubin tests 45-min plasma BSP Normal or elevated; secondary rise at 90 min Elevated; no secondary rise at Cholestatic Hemolysis Defect in Hepatocellular retention 90 min Conjugation Urinary Normal total >80% as coproporphyrin I Elevated total; elevated coproporphyrin proportion of coproporphyrin I but <80% Mode of inheritance Autosomal recessive Autosomal recessive Intrahepatic Extrahepatic Prevalence Uncommon (1:1300 in Persian Jews) Rare Prognosis Benign Benign Mutation MRP2 Jaundice Conjugated bilirubin Unconjugated bilirubin Cholestatic Hemolysis Defect in Hepatocellular Conjugation Intrahepatic Extrahepatic 5 Liver Function Tests • Bilirubin • PT (Prothrombin time) •Glucose • Cholesterol • ALT (alanine aminotransferase) • AST (aspartate aminotransferase) • Alkaline phosphatase • GGT (γ-glutamyltranspeptidase) Imaging • Ultrasound •CT scan Bilirubin • Liver-spleen scan Metabolism • Radionuclide biliary scan •Blood • ERCP (endoscopic retrograde •Conjugated & cholangiopancreatography) Conjugated • Transhepatic cholangiography •Urine – Urobilinogen •Stool – Stercobilin plus 3 O minus Fe Jaundice ↑ BR V minus CO α M Conjugated bilirubin M D A V COOH COOH N N CH CH δ CH2 2 2 CH2 Unconjugated bilirubin Fe β Me CH Me CH2 CH2 Me Me CH N N CH CH A BCCH D ↑ ALT ↑ AP M C B M 2 O N N N N O H H H H γ CH2 CH2 Hemolysis Defect in Cholestatic CH2 CH2 Hepatocellular Bilirubin IX α Conjugation COOH COOH Nl BD Dilated BD Ferroprotoporphyrin IX (Protoheme) Intrahepatic Extrahepatic Conversion of protoheme (ferroprotoporphyrin IX) to bilirubin IXα. Cleavage of the protoporphyrin ring occurs selectively at the α-methene bridge. The bridge carbon atom is oxidized to carbon monoxide. 6 BILIRUBIN IS PRODUCED BY OXIDATION OF HEME AND REDUCTION OF THE RESULTANT BILIVERDIN HEME BILIRUBIN IXα M = Methyl Pr Pr H2 E = Ethyl C M M γ M Pr = Propionyl M N N N N H H β Fe δ H N H N N N BILIVERDIN IXα V α M V M Pr Pr O O C M M H V V M M Biliverdin O & Heme 2 N N Reductase + NADPH Oxygenase H NADP H N H N V M NADP+ Fe3+ O O NADPH CO M V cMOAT MDR2 7 8.
Load more

Recommended publications
  • Hyperbilirubinemia
    Porphyrins Porphyrins (Porphins) are cyclic tetrapyrol compounds formed by the linkage )). of four pyrrole rings through methenyl bridges (( HC In the reduced porphyrins (Porphyrinogens) the linkage of four pyrrole rings (tetrapyrol) through methylene bridges (( CH2 )) The characteristic property of porphyrins is the formation of complexes with the metal ion bound to nitrogen atoms of the pyrrole rings. e.g. Heme (iron porphyrin). Proteins which contain heme ((hemoproteins)) are widely distributed e.g. Hemoglobin, Myoglobin, Cytochromes, Catalase & Tryptophan pyrrolase. Natural porphyrins have substituent side chains on the eight hydrogen atoms numbered on the pyrrole rings. These side chains are: CH 1-Methyl-group (M)… (( 3 )) 2-Acetate-group (A)… (( CH2COOH )) 3-Propionate-group (P)… (( CH2CH2COOH )) 4-Vinyl-group (V)… (( CH CH2 )) Porphyrins with asymmetric arrangement of the side chains are classified as type III porphyrins while those with symmetric arrangement of the side chains are classified as type I porphyrins. Only types I & III are present in nature & type III series is more important because it includes heme. 1 Heme Biosynthesis Heme biosynthesis occurs through the following steps: 1-The starting reaction is the condensation between succinyl-CoA ((derived from citric acid cycle in the mitochondria)) & glycine, this reaction is a rate limiting reaction in the hepatic heme synthesis, it occurs in the mitochondria & is catalyzed by ALA synthase (Aminolevulinate synthase) enzyme in the presence of pyridoxal phosphate as a cofactor. The product of this reaction is α-amino-β-ketoadipate which is rapidly decarboxylated to form δ-aminolevulinate (ALA). 2-In the cytoplasm condensation reaction between two molecules of ALA is catalyzed by ALA dehydratase enzyme to form two molecules of water & one 2 molecule of porphobilinogen (PBG) which is a precursor of pyrrole.
    [Show full text]
  • Porphyrins & Bile Pigments
    Bio. 2. ASPU. Lectu.6. Prof. Dr. F. ALQuobaili Porphyrins & Bile Pigments • Biomedical Importance These topics are closely related, because heme is synthesized from porphyrins and iron, and the products of degradation of heme are the bile pigments and iron. Knowledge of the biochemistry of the porphyrins and of heme is basic to understanding the varied functions of hemoproteins in the body. The porphyrias are a group of diseases caused by abnormalities in the pathway of biosynthesis of the various porphyrins. A much more prevalent clinical condition is jaundice, due to elevation of bilirubin in the plasma, due to overproduction of bilirubin or to failure of its excretion and is seen in numerous diseases ranging from hemolytic anemias to viral hepatitis and to cancer of the pancreas. • Metalloporphyrins & Hemoproteins Are Important in Nature Porphyrins are cyclic compounds formed by the linkage of four pyrrole rings through methyne (==HC—) bridges. A characteristic property of the porphyrins is the formation of complexes with metal ions bound to the nitrogen atom of the pyrrole rings. Examples are the iron porphyrins such as heme of hemoglobin and the magnesium‐containing porphyrin chlorophyll, the photosynthetic pigment of plants. • Natural Porphyrins Have Substituent Side Chains on the Porphin Nucleus The porphyrins found in nature are compounds in which various side chains are substituted for the eight hydrogen atoms numbered in the porphyrin nucleus. As a simple means of showing these substitutions, Fischer proposed a shorthand formula in which the methyne bridges are omitted and a porphyrin with this type of asymmetric substitution is classified as a type III porphyrin.
    [Show full text]
  • Determination of Urinary Porphyrin by DEAE-Cellulose Chromatography and Visual Spectrophotometry
    A n n a l s o f C l i n i c a l a n d L a b o r a t o r y S c i e n c e , Vol. 4, No. 1 Copyright © 1974, Institute for Clinical Science Determination of Urinary Porphyrin by DEAE-Cellulose Chromatography and Visual Spectrophotometry MARTHA I. WALTERS, P h .D.* Ohio Valley Hospital, Steubenville, OH 43952 ABSTRACT A simple, reliable and rapid method for the isolation and determination of urinary porphyrins is described. Both uroporphyrin and coproporphyrin are quantitatively adsorbed by DEAE cellulose. Urobilinogen, urobilin, and bili­ rubin are removed with sodium acetate. The isolated porphyrins, eluted with 1 N HC1, are measured spectrophotometrically, and the excretion is related to that of creatinine. Porphyrin excretion was studied in normal adults and children, and in patients with disorders of porphyrin metabolism ( e.g., in lead poisoning, hemolytic anemia, hepatic disease and porphyria) in order to eval­ uate the method. The coefficient of variation of replicate analyses of a sample containing 200 ¡xg porphyrin per gm creatinine was 3.5 percent. The correlation coefficient between 83 duplicate analyses was 0.993. Introduction or adsorption onto an adsorbant followed Patients with porphyria show great in­ by elution. Methods combining extraction creases in the excretion of uroporphyrin, and adsorption have been the most com­ coproporphyrin and their precursors indi­ monly used,3’12 but procedures employing cating a primary abnormality of porphyrin ion-exchange chromatography,11’13 electro­ synthesis (figure 1). In addition to these phoresis,4’10 and thin-layer chromatogra­ disorders, there are a number of diseases phy15’16 also have been described.
    [Show full text]
  • PORPHYRIA by PROFESSOR CHARLES GRAY King's College Hospital Medical School, London
    i86 Postgrad Med J: first published as 10.1136/pgmj.32.366.186 on 1 April 1956. Downloaded from PORPHYRIA By PROFESSOR CHARLES GRAY King's College Hospital Medical School, London Three types of porphyria are recognized The involvement of the central nervous system clinically: (i) A congenital, or photo-sensitive, leads to irregularly distributed flaccid paralyses, form, (2) an acute intermittent form and (3) a sometimes involving only a single muscle group, chronic or mixed form. Although on clinical sometimes involving most of the striated muscle of grounds these differ greatly from one another so the body. The clinical picture is very varied, that they have been regarded as distinct diseases, it however, and the neurological features may be now seems possible that this is not so. They are limited to ptosis, a facial palsy, diplopia, disphonia usually regarded as uncommon diseases but it is or dysphasia. Many cases have been erroneously likely that as they become more widely known they diagnosed as hysteria, acute psychosis, polio- will more frequently be recognized. The por- myelitis or encephalitis. These neurological phyrias are characterized by an abnormal excretion manifestations are essentially those of a poly- of porphyrins or of porphyrin derivatives. Normal neuritis and histological studies reveal a patchy urine and faeces contain minute quantities of degeneration of peripheral nerves and anterior porphyrins and only small increases in the horn cells. When the bulbar centres are affected quantities' excreted occur in such conditions as there is early respiratory failure and rapid death.by copyright. pernicious anaemia, liver disease, lead poisoning, On the other hand, if recovery occurs it may be poliomyelitis and various forms of haemolytic remarkably complete even in the most serious anaemia.
    [Show full text]
  • A High Urinary Urobilinogen / Serum Total Bilirubin Ratio Reported in Abdominal Pain Patients Can Indicate Acute Hepatic Porphyria
    A High Urinary Urobilinogen / Serum Total Bilirubin Ratio Reported in Abdominal Pain Patients Can Indicate Acute Hepatic Porphyria Chengyuan Song Shandong University Qilu Hospital Shaowei Sang Shandong University Qilu Hospital Yuan Liu ( [email protected] ) Shandong University Qilu Hospital https://orcid.org/0000-0003-4991-552X Research Keywords: acute hepatic porphyria, urinary urobilinogen, serum total bilirubin Posted Date: June 14th, 2021 DOI: https://doi.org/10.21203/rs.3.rs-587707/v1 License: This work is licensed under a Creative Commons Attribution 4.0 International License. Read Full License Page 1/10 Abstract Background: Due to its variable symptoms and nonspecic laboratory test results during routine examinations, acute hepatic porphyria (AHP) has always been a diagnostic dilemma for physicians. Misdiagnoses, missed diagnoses, and inappropriate treatments are very common. Correct diagnosis mainly depends on the detection of a high urinary porphobilinogen (PBG) level, which is not a routine test performed in the clinic and highly relies on the physician’s awareness of AHP. Therefore, identifying a more convenient indicator for use during routine examinations is required to improve the diagnosis of AHP. Results: In the present study, we retrospectively analyzed laboratory examinations in 12 AHP patients and 100 patients with abdominal pain of other causes as the control groups between 2015 and 2021. Compared with the control groups, AHP patients showed a signicantly higher urinary urobilinogen level during the urinalysis (P < 0.05). However, we showed that the higher urobilinogen level was caused by a false- positive result due to a higher level of urine PBG in the AHP patients. Hence, we used serum total bilirubin, an upstream substance of urinary urobilinogen synthesis, for calibration.
    [Show full text]
  • Porphyrins and Bile Pigments: Metabolism and Disorders Dr
    Porphyrins and bile pigments: metabolism and disorders Dr. Jaya Chaturvedi Porphyrins • Porphyrins are cyclic compounds formed by the linkage of four pyrrole rings through methyne (ÓHC—) bridges.In the naturally occurring porphyrins, various side chains replace the eight numbered hydrogen atoms of the pyrroles. • Porphyrins have had different structures depend on side chains that are attached to each of the four pyrrole rings. For example; Uroporphyrin, coporporphyyrin and protoporphyrin IX (heme). • The most prevalent metalloporphyrin in humans is heme, which consists of one ferrous (Fe2+) iron ion coordinated at the center of the tetrapyrrole ring of protoporphyrin IX. What is bilirubin? •Bilirubin is a yellowish pigment found in bile, a fluid made by the liver. •The breakdown product of Hgb from injured RBCs and other heme containing proteins. •Produced by reticuloendothelial system •Released to plasma bound to albumin •Hepatocytes conjugate it and excrete through bile channels into small intestine. Bilirubin di-glucoronid Structure of heme: • Heme structure: a porphyrin ring coordinated with an atom of iron side chains: methyl, vinyl, propionyl • Heme is complexed with proteins to form: • Hemoglobin, myoglobin and cytochromes Pathway of Heme Biosynthesis. Heme biosynthesis begins in the mitochondria from glycine and succinyl- CoA, continues in the cytosol, and ultimately is completed within the mitochondria. The heme that it produced by this biosynthetic pathway is identified as heme b. PBG: porphobilinogen; ALA: δ- aminolevulinic
    [Show full text]
  • Conversion of Amino Acids to Specialized Products
    Conversion of Amino Acids to Specialized Products First Lecture Second lecture Fourth Lecture Third Lecture Structure of porphyrins Porphyrins are cyclic compounds that readily bind metal ions (metalloporphyrins)—usually Fe2+ or Fe3+. Porphyrins vary in the nature of the side chains that are attached to each of the four pyrrole rings. - - Uroporphyrin contains acetate (–CH2–COO )and propionate (–CH2–CH2–COO ) side chains; Coproporphyrin contains methyl (–CH3) and propionate groups; Protoporphyrin IX (and heme) contains vinyl (–CH=CH2), methyl, and propionate groups Structure of Porphyrins Distribution of side chains: The side chains of porphyrins can be ordered around the tetrapyrrole nucleus in four different ways, designated by Roman numerals I to IV. Only Type III porphyrins, which contain an asymmetric substitution on ring D are physiologically important in humans. Physiologically important In humans Heme methyl vinyl 1) Four Pyrrole rings linked together with methenyle bridges; 2) Three types of side chains are attached to the rings; arrangement of these side chains determines the activity; 3) Asymmetric molecule 3) Porphyrins bind metal ions to form metalloporphyrins. propionyl Heme is a prosthetic group for hemoglobin, myoglobin, the cytochromes, catalase and trptophan pyrrolase Biosynthesis of Heme The major sites of heme biosynthesis are the liver, which synthesizes a number of heme proteins (particularly cytochrome P450), and the erythrocyte-producing cells of the bone marrow, which are active in hemoglobin synthesis. Heme synthesis occurs in all cells due to the requirement for heme as a prosthetic group on enzymes and electron transport chain. The initial reaction and the last three steps in the formation of porphyrins occur in mitochondria, whereas the intermediate steps of the biosynthetic pathway occur in the cytosol.
    [Show full text]
  • Recent Studies Ofthe Urobilin Problem1
    J Clin Pathol: first published as 10.1136/jcp.16.1.1 on 1 January 1963. Downloaded from J. clin. Path. (1963), 16, 1 --Recent studies of the urobilin problem1 C. J. WATSON2 From the Department of Medicine, University of Minnesota Hospital, Minneapolis, Minn. It is now almost a century since Jaffe (1868, 1869) 1961). Sjostrand (1949) demonstrated that this is described urobilin. It would manifestly be an imposi- lost as CO, an important observation not yet tion on your patience if I were to attempt any com- exploited to any extent by clinical investigators. It is prehensive treatment of the ensuing history of this intriguing that the opening of the porphyrin ring to topic, but I shall strive to bring together for you a form bile pigment involves only the ix bridge carbon. few of what seem to me the more important mile- A number of years ago Schwartz and I (Watson and stones in their relation to recent studies. For reasons Schwartz, 1942) converted the bilirubins from each that will become apparent, the term urobilin, both of a series of human fistula biles to urobilinogen, on historical and clinical chemical grounds, is best thence to a crystalline urobilin, which was shown to applied to a group of closely related substances. be the same in all instances, i.e., 9, ax in type. Gray, Under ordinary circumstances the urobilin group is Nicholson, and Nicolaus (1958) at King's College related mainly to destruction of the haemoglobin of Hospital, using a much more elegant and precise circulating red cells. Other possible sources will be method depending on oxidation to monopyrrolic referred to later.
    [Show full text]
  • Abdulrahem Batool Bdour
    34 Batool bdour Abdulrahem ... Diala Abu-Hassan Hello there, in this lecture we’ll talk about Heme, the irony unit in the heart of a number of proteins, stay tuned! It’s going to get colorful towards the end. Amino acids are used to synthesize a variety of other molecules with specialized functions. And today we’ll talk about ◆ Porphyrins’ structure: It’s a cyclic structure composed of four pyrrole rings, connected This is a pyrrole ring together. In each ring there’s a nitrogen towards the center of with 2 side chains porphyrin structure and there are two side chains coming out from each ring. Heme: Is a porphyrin with a ferrous atom (Fe2+) in the middle. It’s the most prevalent metalloporphyrin in humans. Heme is found in hemoglobin, myoglobin, the cytochromes, catalase, nitric oxide synthase, and peroxidase. Hemeproteins are rapidly synthesized and degraded. 6–7g of hemoglobin are synthesized each day to replace heme lost through the normal turnover of erythrocytes Porphyrins differ from each other in the side chains that come out of the pyrrole ring and the order or distribution of these side chains. Side chains Example: On the sides of this box, we have the structures of two porphyrins: uroporphyrin I & uroporphyrin III. There are two types of side chains that are repeated on each pyrrole ring, designated A and P which stand for acetate and propionate. How to differentiate between these two porphyrins? we look at the order of these side chains. On A, B & C pyrroles of both porphyrins, A and P Uroporphyrin I (1) are in the order A-P/A-P/A-P.
    [Show full text]
  • Interpretation of Urine Analysis
    UNDERSTANDING URINALYSIS Slides __________________________________________________________________________________________________________ Urine Analysis Interpretation of • Appearance or color • Specific gravity • pH Urine Analysis • Leukocyte esterase March 2015 • Nitrites • Urobilinogen • Bilirubin • Glucose • Ketones • Protein • Blood • Microscopic examination Denise K Link, MPAS, PA-C The University of Texas Southwestern Medical Center [email protected] Proper Specimen Collection Routine Urine Analysis Appearance Chemical tests (dipstick) • Teach every patient how to collect proper specimen • pH 1. Clean-catch midstream • Protein 2. In patients with indwelling urinary catheters, a • Glucose recently produced urine sample should be obtained • Ketones (directly from the catheter tubing) • Blood 3. Best examined when fresh. Chemical composition • Urobilinogen of urine changes with standing and formed • Bilirubin elements degenerate with time • Nitrites • Leukocyte esterase 4. Refrigerated is best when infection is suspected • Specific gravity 5. First voided morning urine is ideal when evaluating suspected glomerulonephritis Microscopic examination of spun urinary sediment Urine Analysis with Microscopy Dipstick Methodology • Paper tabs impregnated with chemical reagents • Reagents are chromogenic • Reagents are timed developed • Some rxns are highly specific • Other are sensitive to the presence of interfering substances or extremes of pH • Rapid, semiquantitative assessment of urinary characteristics © 2015 National Kidney Foundation,
    [Show full text]
  • 7 Bilirubin Metabolism
    #7 Bilirubin metabolism Objectives : ● Definition of bilirubin ● The normal plasma concentration of total bilirubin ● Bilirubin metabolism : - Bilirubin formation - Transport of bilirubin in plasma - Hepatic bilirubin transport - Excretion through intestine ● Other substances conjugated by glucuronyl transferase. ● Differentiation between conjugated & unconjugated bilirubin ● Other substances excreted in the bile ● Definition of Jaundice ● Classification of jaundice ( Prehepatic / Hepatic / poat-hepatic ). Doctors’ notes Extra Important Resources: 435 Boys’ & Girls’ slides | Guyton and Hall 12th & 13th edition Editing file [email protected] 1 Overview- mind map Porphyrin Metabolism (Boys’ slides) : ● Porphyrins are cyclic compounds that readily bind metal ions usually Fe2+ or +3 Fe which can carry O2. ● Porphyrins are heterocyclic macrocycles composed of four modified pyrrole (a colorless, toxic, liquid, five-membered ring compound, C4 H5 N) subunits interconnected at their α carbon atoms via methine bridges (=CH-). ● The most prevalent porphyrin in the human is heme, which consists of one ferrous (Fe2+ ) iron ion coordinated in the center of tetrapyrrole ring of protoporphyrin IX. ● Structure of Hemoglobin showing the polypeptides backbone that are composed of four subunits: 2 α and 2 β subunits. Every subunit is consisted of one ferrous (Fe2+ ) iron ion coordinated in the center porphyrin compound. The most prevalent porphyrin in the human is heme Definition of bilirubin : ● Bilirubin is the end product of heme degradation derived from breakdown senescent (aging) erythrocytes by mononuclear phagocytes system specially in the spleen, liver and bone marrow. (It is the water insoluble breakdown product of normal heme catabolism). ● Bilirubin is the greenish yellow pigment excreted in bile, urine and feces. ● The major pigment present in bile is the orange compound bilirubin.
    [Show full text]
  • Clinical Biochemistry Liver Function Tests
    مرحلة ثالثة الدراسة الصباحية Clinical Biochemistry Liver function tests The liver is the largest organ in the body It is located below the diaphragm in the right upper quadrant of the abdominal cavity and extended approximately from the right 5th rib to the lower border of the rib cage. The liver is separated into a right and left lobe, separated by the falciform ligament. The right is much larger than the left. Functions of liver ① Excretory function: bile pigments, bile salts and cholesterol are excreted in bile into intestine. ② Metabolic function: liver actively participates in carbohydrate, lipid, protein, mineral and vitamin metabolisms. ③ Hematological function: liver is also produces clotting factors like factor V, VII. Fibrinogen involved in blood coagulation is also synthesized in liver. It synthesizes plasma proteins and destruction of erythrocytes. ④ Storage functions: glycogen, vitamins A, D and B12, and trace element iron are stored in liver. ⑤ Protective functions and detoxification: Ammonia is detoxified to urea. kupffer cells of liver perform phagocytosis to eliminate foreign compounds. Liver is responsible for the metabolism of xenobiotic. 1 م.م. وفاء حفظي عجام Classification of liver functions test Classified based on the major functions of liver: ① Excretion: Measurement of bile pigments, bile salts. ② Serum enzymes: Transaminase (ALT, AST), alkaline phosphate (ALP), 5’-nucleotidase, LDH isoenzyme. ③ Synthetic function: Prothrombin time, serum albumin. ④ Detoxification : Excretion: Bilirubin Bilirubin is the main bile pigment that is formed from the breakdown of heme in red blood cells. The broken down heme travels to the liver, where it is secreted into the bile by the liver. Serum bilirubin Normally, a small amount of bilirubin circulates in the blood.
    [Show full text]