transketolase in rbc

IMHA may be primary, secondary to neoplasia or other diseases, or may result from RBC organisms such as Mycoplasma Haemophilus. Elliptocytes result from abnormalities in spectrin and other membrane proteins and their interaction with the lipid bilayer. Also, thiamine can be assayed indirectly by assaying RBC transketolase and reassaying after adding excess thiamine pyrophosphate to the test tubes. Target cells result from a balanced excess accumulation of both cholesterol and phospholipids and form later in the course of cholestatic disease (i.e., 1 week later than acanthocytes) because of the slower rate of phospholipid (vs cholesterol) exchange. Looks like you’ve clipped this slide to already. Poikilocytosis is a qualitative measure of RBC shape. Abnormalities are graded as slight, moderate or marked (or 1+ to 4+). Clinical Aspects • Wernicke-Korsakoff syndrome : - Genetic disorder - Alteration in transketolase activity - Symptoms : mental disorder, loss of memory, partial paralysis • Pernicious anemia : transketolase activity increases. The Merck Manual of Diagnosis and Therapy 19th Edition - Copy. Iron deficiency, whatever the underlying cause, results in microcytic hypochromic anemia, often with mild to moderate poikilocytosis. Macrocytic red cells resembling reticulocytes may result that have abnormally high membrane cholesterol content. Phospholipids are asymmetrically distributed within the bilayer, with hydrophobic long chain fatty acids oriented towards the inner core of the membrane. Other poikilocytes result from membrane lipid and protein abnormalities that decrease deformability and make RBCs more fragile and susceptible to fragmentation and to oxidative stress. Nursing animals also are susceptible to iron deficiency. GANDHAM RAJEEV-BIOCHEMISTRY IMPORTANT QUESTIONS-RGUHS-2017, No public clipboards found for this slide. READ PAPER. Feline acanthocytes have few blunt projections and may appear to be misshapen RBCs. Abnormal RBC Morphology Caused by Electrolyte and Metabolic Abnormalities. NADPH is required for the reduction of glutathione, an antioxidant preventing excess hydrogen peroxide and free radicals from damaging RBC membranes. In addition to spherocytosis, RBC agglutination commonly occurs in IMHA. Other, more reliable lab markers include erythrocyte transketolase activity and RBC (red blood cells) thiamine diphosphate, but these tests are more expensive and don’t give quick results [64, 29]. Rouleau occurs with decreased negative charges on the RBC membrane caused by increased concentrations of positively-charged proteins in plasma (i.e., fibrinogen, immunoglobins), usually in association with chronic inflammatory disease. RBC morphology is assessed qualitatively on a well-made blood smear and includes RBC distribution, anisocytosis, poikilocytosis, polychromasia/hypochromasia, and inclusions or organisms. Vitamin B1 deficiency causes B er 1B er 1. • The occurrence & manifestation of Wernickes korsakoffs syndrome (encephalopathy) which is seen in alcoholics & those with thiamine deficiency is due to a genetic defect in the enzyme transketolase. Quantitative Evaluation of RBC Morphology. Thiamine can be assayed directly (eg, through Specialty Laboratories of Santa Monica, California). B1, Thiamine or thiamin . Dietary lipid also can affect RBC membrane lipid composition and morphology. In dogs and cats, iron deficiency most commonly is caused by chronic blood loss from gastrointestinal bleeding (ulcers, neoplasia), severe flea infestation, hematuria (neoplasia) or coagulopathies. Evaluation and interpretation of red blood cell (RBC) morphology is an important component of a complete blood count (CBC). Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. More than 50% of cats with liver disease have poikilocytosis (usually acanthocytes), and serum cholesterol concentrations are higher in cats with more severe poikilocytosis. Echinocytes and echinocytic elliptocytes (burr cells) have been reported in dogs with renal disease (glomerulonephritis) and in humans with uremia, where they are thought to reflect changes in the metabolic environment and are associated with decreased red cell lifespan. Target cells result from excess membrane relative to low intracellular hemoglobin concentration. Other causes of spherocytosis are coral snake envenomation and zinc toxicity. RBCs in uremic patients have decreased transketolase activity, increased susceptibility to oxidants, and decreased Na/K ATPase activity leading to altered shape, increased rigidity, and susceptibility to mechanical fragmentation. Eccentrocytes are another important clue to oxidative damage in canine RBCs and are formed by the adhesion of opposing inner cytoplasmic membranes. Shortly after receiving an anti-malarial drug, symptoms started to appear. RDW increases when microcytes and fragments form, and then normalizes. Glucose breakdown and synthesis are essential processes in the human body. Membrane enzymes depend on the integrity of phospholipids for normal function. Fusiform cells may be found in birds. Some new hematology analyzers determine the percentage and number of hypochromic (and hyperchromic) cells of different sizes. Spherocytes results from antibody binding to the RBC membrane, and subsequent removal of a portion of the membrane by a macrophage, usually in the spleen but also in liver and bone marrow. Once produced, the shape change usually is irreversible. hyponatremia (<136 mmol/L) as well as hypochloremia, low TCO2, hypo-osmolality, and hypocalcemia. Animals fed sunflower oil had more target cells and animals fed fish oil had more echinocytes compared with animals fed olive oil. Leptocytes and target cells (codocytes) also may be observed in hepatic insufficiency, especially in dogs and cats with portocaval shunts. Microangiopathy is the deposition of fibrin strands or microthrombi in small blood vessels. Because mature RBCs cannot synthesize lipids, they rely on a continuous exchange of lipids between their membranes and plasma lipoproteins for homeostasis. Movement of free cholesterol between plasma and lipid bilayer is rapid and dynamic; membrane phospholipid turnover with plasma is a passive process that occurs very slowly. The most common red cell shape abnormalities in dogs and cats with liver disease are echinocytes and/or acanthocytes (spur cells). During erythropoiesis and during the 2-5 months spent in circulation, RBCs are exposed to the biochemical milieu of plasma and are reliant on the availability of biochemical precursors needed for membrane and hemoglobin synthesis. Thiamine pyrophosphate is also a coenzyme of the transketolase system by which direct oxidation of glucose occurs in the cytoplasm of cells via the pentose phosphate pathway. In thiamine deficiency (also in pernicious anemia) transketolase activity is decreased in blood. These cells form when erythrocyte membranes contain excess cholesterol compared to phospholipids (increased cholesterol:phospholipid ratio), due to hypercholesterolemia or abnormal lipoprotein composition. Abnormal RBC Morphology Caused by Iron Deficiency. 54 55. RBC inclusions include basophilic stippling, Heinz bodies, Howell-Jolly bodies and RBC organisms, such as Mycoplasma hemophilus, Babesia canis, and Eperythrozoon spp. Abnormal RBC Morphology Caused by Immune-Mediated Disease. Vitamin B₂ (riboflavin) Characteristics. Animals fed olive oil had the highest percentage of normal discocytes, suggesting yet another beneficial aspect of this dietary fat. Heinz bodies in cats are often larger and usually single, compared with Heinz bodies in dogs. The lipid bilayer of the erythrocyte membrane is a permeability barrier composed of about equal amounts of cholesterol and phospholipids. Abnormal lipid metabolism alters the lipid composition of RBC membranes and reduces RBC deformability. The cytoskeleton helps determine and maintain the shape of red cells through the arrangement and interactions of cytoskeletal proteins. Phospholipases in rattlesnake and coral snake venom result in dose-dependent echinocytosis. If you continue browsing the site, you agree to the use of cookies on this website. Anisocytosis is a qualitative measure of variability in RBC size. If both macrocytes and microcytes are present, the MCV may be normal. RBC indices are quantitative indicators of RBC morphology. Olive oil is rich in monounsaturated fatty acids, whereas, sunflower oil is rich in linoleic and arachidonic acids (n-6 PUFAs), and fish oil is rich in n-3 PUFAs. Abnormal RBC Morphology Caused by Hepatic Disease. Polychromasia refers to the light blue color of immature RBCs (caused by residual RNA). Increased RDW may be a sensitive means of detecting early iron deficiency, especially in cats. Anemia is variable in severity, and can be mild or even absent. Polychromasia is the most important indicator of responsiveness to anemia, and may be further quantitated by counting reticulocytes. Altered lipoprotein metabolism also can inhibit the maturation of erythrocytes in the bone marrow, at the time at which they are discarding their nuclei and organelles and assuming a flexible biconcave shape. erythrocyte [ĕ-rith´ro-sīt] one of the formed elements in the peripheral blood, constituting the great majority of the cells in the blood. Target cells also may form because of decreased hemoglobin concentration secondary to altered iron metabolism, which may occur in hepatic insufficiency. Contents Introduction List of Abbreviations List of Acronyms of Cancer Organisations The Female Reproductive Organs Combined List of Abbreviations and Acronyms Introduction. Mary M. Christopher, DVM, PhD, DACVP, DECVCP The cytoskeleton delimits membrane deformability and confers the physical properties necessary for normal shape changes during circulation. See our Privacy Policy and User Agreement for details. The RDW is a quantitative index of variability in RBC size, and is increased in regenerative anemia and iron deficiency anemia. Red cell morphology may be altered by alterations in lipid, iron and oxidative metabolism, immune-mediated disease, mechanical fragmentation, and by electrolyte or metabolic abnormalities. RBC morphology may provide important diagnostic information regarding the underlying cause of anemia and systemic disease. Evaluation and interpretation of red blood cell (RBC) morphology is an important component of a complete blood count (CBC). Agglutination refers to small groups or clumps of RBCs that result from the interaction between bound antibodies on the surface of RBCs. Hypercholesterolemia usually is associated with severe cholestatic disease, and is accompanied in dogs and humans by increased serum levels of lipoprotein X as well as other abnormal lipoproteins. A well-nourished physician of Mediterranean heritage is suffering fatigue while doing missionary work in Africa. This section aims to provide a reference list of abbreviations and acronyms that are frequently used within oncology. [MN Chatterjea]Textbook of Medical Biochemistry (8th Ed.) Most shape changes result from alteration of the red cell membrane. You can change your ad preferences anytime. Thiamine Deficiency • The transketolase activity is measured in RBCs is an index of the thiamine status of an individual. Transaldolation reaction: Role: B1 is a coenzyme that helps the body produce energy, is involved in glucose, amino acid, lipid, and alcohol metabolism, and is required for the proper functioning of the nervous system, heart, and muscles. The type of shape abnormality must be specified. 16 Full PDFs related to this paper. The MCV may be increased (macrocytosis) or decreased (microcytosis). Animals with portocaval shunts and other hepatic diseases may develop "functional iron deficiency" with similar RBC morphologic changes. Increased MCH or MCHC is an artifact secondary to Heinz bodies, lipemia, or hemoglobinemia. The biochemical cause of echinocytosis in renal disease is unknown. With transfusion or iron treatment, the RDW again increases, as normocytic RBCs mix with microcytes. A high percentage of polychromatophilic cells (reticulocytes) may result in an increased MCV and decreased MCH or MCHC. Both hypochromasia and microcytosis may be difficult to assess visually, but usually are detectable with changes in RBC indices. It is catalysed by the enzyme transketolase and the coenzyme is Thaimine pyrophosphate (TPP). Other disorders that cause microangiopathy and RBC fragmentation are chronic disseminated intravascular coagulation, heartworm disease, valvular vegetative endocarditis, and glomerulonephritis. Red cell fragmentation (schistocytes, keratocytes, and blister cells) may occur in hepatic insufficiency when microangiopathy develops secondary to decreased coagulation factor production and clearance. Anemia is variably regenerative and characterized by microcytosis, hypochromasia (not always in cats), and increased RDW. Phases. University of California-Davis, School of Veterinary MedicineDavis, CA, Interpretation of Red Blood Cell Morphology (Advanced Level), World Small Animal Veterinary Association World Congress Proceedings, 2004, Mary M. Christopher, DVM, PhD, DACVP, DECVCP, University of California Davis, Department of Pathology, Microbiology, and Immunology School of Veterinary Medicine. RBC fragmentation is not usually seen in feline Heinz body hemolytic anemia, because the spleen does not contribute to RBC lysis. Now customize the name of a clipboard to store your clips. Hypochromic cells are almost always also microcytic. Glucose provides the required substrates for aerobic and anaerobic metabolism. Heinz bodies in dogs result in hemolysis, with poikilocytosis (keratocytes, schistocytes, a few spherocytes). MCH and MCHC indicate hemoglobin concentration; decreased values indicate hypochromasia. Echinocytosis has been linked to total body cation depletion in horses with colitis or with furosemide administration, and is associated with. Red cell shape is a result of both the environment of the cell and its metabolic status. When low numbers of spherocytes are seen with other types of poikilocytes, diseases causing RBC fragmentation are more likely. See our User Agreement and Privacy Policy. (For immature forms see erythrocytic series.) Your doctor may also perform a physical exam and look for deficiency symptoms. First Aid for the USMLE Step 1 2018. If you continue browsing the site, you agree to the use of cookies on this website. In cats with many large Heinz bodies, evaluation for ketosis is recommended. Abnormal RBC Morphology Caused by Mechanical Fragmentation. Echinocytes also have been described in dogs with neoplasia (lymphoma, hemangiosarcoma, mast cell tumor, carcinoma) and in people with sepsis. Fragmentation may result in schistocytes and acanthocytes; acanthocytes also may be seen in conjunction with renal disease-induced lipid abnormalities. These tumors are essentially giant masses of thrombotic blood vessels and sinuses. Lab tests indicate low RBC's and a urine test indicates the presence of free hemoglobin. Clipping is a handy way to collect important slides you want to go back to later. Download PDF Transfer of 2-carbon moiety i.e., active glycelaldehyde is known as transketolation. In cats, an increased percentage of Heinz bodies with no history of drug toxicity may reflect diet (e.g., onions, fish) or underlying disease, especially ketoacidotic diabetes mellitus, lymphoma, and hyperthyroidism. Originally thought to be an amine, the ‘e’ was dropped when the formula became known, but the spelling using the ‘e’ is still used in many texts and across the internet. K. Thornton, E. Villamor, in Encyclopedia of Food and Health, 2016 Nutritional Epidemiology. Erythrocyte (RBC) levels of metabolites of this system have been used to indicate thiamine status in experimental animals, including salmon and trout. Diagnostics: vitamin B 1 administration → ↑ RBC transketolase activity; In malnourished or alcohol-dependent patients, always administer thiamine before giving dextrose to decrease the risk of precipitating or exacerbating Wernicke encephalopathy. We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. Poikilocytes seen most often in iron deficiency are target cells, leptocytes, schistocytes, elliptocytes, and dacryocytes. Agglutination can falsely increase the MCV. Rouleaux also may form normally in feline blood and as an artifact due to slow drying of the blood smear. Abnormal RBC Morphology Caused by Oxidative Damage. Agglutination may be the only RBC morphologic abnormality in IMHA in cats, and must be differentiated from rouleaux. Glucose 6-phosphate for the production of NADPH (by the reduction of coenzyme NADP) and a Pentose sugar.. Changes in the distribution of the phospholipids may have profound effects on red cell shape and other cell properties. Cholesterol is in the free, unesterified form; phospholipids are a mixture of lecithin (phosphatidylcholine), phosphatidylethanolamine, sphingomyelin, phosphatidylserine, and phosphatidylinositol. Several commercial laboratories can perform this assay. URONIC ACID … Thiamin(e), vitamin B1, is spelled with and without an ‘e’. The combination of turbulent blood flow through sinuous and rough, neoplastic vessels yields a unique mix of schistocytes, acanthocytes, keratocytes, dacryocytes, blister cells, and a few spherocytes. Hypercholesterolemia and cholesterol uptake into red cell membranes is further enhanced in hepatic insufficiency and obstructive liver disease by decreased activity of lecithin cholesterol acyltransferase (LCAT), the enzyme responsible for cholesterol esterification, resulting in decreased production of cholesterol esters and a subsequent increase in free cholesterol. Pentose phosphate pathway is defined as the metabolic pathway that occurs in all living organisms, and it utilizes the first intermediate product of glycolysis, i.e. Oxidative damage to hemoglobin results in Heinz body formation (oxidation of globin chains) and/or methemoglobinemia (oxidation of iron). Liver disease is the most common causes of lipid-induced red cell shape changes because of its wide-ranging effects on phospholipid metabolism and plasma phospholipid concentrations. First Aid for the USMLE Step 1 2018 The principal proteins--spectrin, actin, protein 4.1, and ankyrin--form a hexagonal lattice that underlies and attaches to the lipid bilayer via trans-membrane proteins (band 3 and glycophorins). Glycolysis versus gluconeogenesis. Feline RBCs with Heinz bodies, especially those caused by oxidant drugs, also can undergo hemolysis, such that "ghost cells" are seen on blood smears. Nutritional epidemiology is the application of epidemiological methods to the study of how diet is related to health and disease in humans at the population level. Meaning of Pentose Phosphate Pathway. Acanthocyte membranes are enriched with cholesterol by 50% to 70%. This physician doesn't have a history of heavy alcohol consumption. Mukhammed Seidaly. Echinocytes (crenation) and torocytes may result from prolonged storage of blood in EDTA; target cells and stomatocytes may result from slow drying of the blood smear. While methemoglobinemia does not alter RBC morphology, Heinz bodies are visible as spherical, slightly refractile spots on the RBC; they are much more easily seen on new methylene blue-stained smears. Academia.edu is a platform for academics to share research papers. Hypochromasia refers to pale RBCs with a wide central pallor. In this presentation, I will discuss the pathophysiologic mechanisms of RBC morphologic alterations in dogs and cats (with an emphasis on shape changes) and their significance in the diagnosis of disease. RBCs passing through microangiopathic vessels are prone to mechanical fragmentation. Like RDW, anisocytosis is increased when microcytic or macrocytic RBC (or both) are present, or when spherocytes are present (which have normal MCV but appear smaller on smears). Spherocytes are primarily identified in dogs; they are difficult, if not impossible, to identify in cats. Splenic hemangiosarcoma is a disease that best characterizes microangiopathic fragmentation in dogs. In immune-mediated hemolytic anemia (IMHA), spherocytes are the sole or primary type of poikilocyte observed. Eccentrocytes that have become spherical with only a small tag of cytoplasm remaining are called pyknocytes. Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. RBC distribution abnormalities include rouleaux and agglutination. Cholesterol enrichment of the membrane expands the outer leaflet of the lipid bilayer, distorts cell contours, disturbs cell functions and accelerates cell destruction. RBC morphology may provide important diagnostic information regarding the underlying cause of anemia and systemic disease. Also known as: Vitamin F, Aneurin, Thiamine diphosphate (TDP) – physiologically active form. Download. Cats with liver disease also often have elliptocytes or ovalocytes, which suggest uncoupling of cytoskeletal proteins from the lipid bilayer secondary to changes in phospholipid composition.

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