Chapter 100 Megaloblastic Anemias (Part 3) docx

... polyglutamate derivatives) act as coenzymes in the transfer of single-carbon units (Fig. 100- 1 and Table 100- 2). Two of these reactions are involved in purine and one in pyrimidine synthesis necessary ... for S-adenosylmethionine (SAM), the universal methyl donor involved in > ;100 methyltransferase reactions (Fig. 100- 1). ... of the folate coenzyme is not recycled during thymid...

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... cobalamin per liter of plasma DHF, dihydrofolate; THF, tetrahydrofolate. Chapter 100. Megaloblastic Anemias (Part 2) IF is produced in the gastric parietal cells of the fundus and body ... derivatives; (2) they usually contain a single carbon unit (Table 100- 2), and (3) 70–90% of natural folates are folate-polyglutamates. Table 100- 2 Biochemical Reactions of Folate Co...

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... proteinuria Tropical sprue Transcobalamin II deficiency Fish tapeworm Chapter 100. Megaloblastic Anemias (Part 7) Ineffective Hemopoiesis There is an accumulation of unconjugated ... randomly selected, young, adult Indian vegans, but the deficiency usually does not progress to megaloblastic anemia since the diet of most vegans is not totally lacking cobalamin and th...

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... disease. Blood 109:412, 2007 He Q et al: Amnionles function is required for cubilin brush- border Megaloblastic Anemia Not Due to Cobalamin or Folate Deficiency or Altered Metabolism This may ... Antiviral nucleoside analogues used in treatment of HIV infection may also cause macrocytosis and megaloblastic marrow changes. In the rare disease orotic aciduria, two consecutive enzymes...

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... myelodysplasia Chapter 100. Megaloblastic Anemias (Part 1) Harrison's Internal Medicine > Chapter 100. Megaloblastic Anemias Megaloblastic Anemias: Introduction The megaloblastic anemias ... or abnormalities of cobalamin metabolism (see Tables 100- 3, 100- 4) Folate deficiency or abnormalities of folate metabolism (see Table 100- 5) Therapy with anti...

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... starvation, or the methylfolate trap. Chapter 100. Megaloblastic Anemias (Part 4) Biochemical Basis of Megaloblastic Anemia The common feature of all megaloblastic anemias is a defect in DNA synthesis ... 5,10- methylene-THF is reduced in either cobalamin or folate deficiency. An alternative theory for megaloblastic anemia in cobalamin or folate deficiency is misinc...

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... explain its reported association with a lower risk for colorectal cancer. Other Chapter 100. Megaloblastic Anemias (Part 5) An underlying maternal folate metabolic abnormality has also been ... severe homocystinuria (blood levels 100 µmol/L) due to deficiency of one of three enzymes, methionine synthase, MHTFR, or cystathionine synthase (Fig. 100- 1), suffer from vascular d...

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... Chapter 100. Megaloblastic Anemias (Part 6) Psychiatric disturbance is common in both folate and cobalamin deficiencies. ... with considerable anisocytosis and poikilocytosis, are the main feature (Fig. 100- 2A ). The MCV is usually > ;100 fL unless a cause of microcytosis (e.g., iron deficiency or thalassemia trait) ... (e.g., dopamine) as well as of proteins, phospho...

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... Addison's disease. It is also associated with hypogammaglobulinemia, with Chapter 100. Megaloblastic Anemias (Part 8) Table 100- 4 Malabsorption of Cobalamin May Occur in the Following Conditions ... Europeans but occurs in all countries and ethnic groups. The overall incidence is about 120 per 100 000 population in the United Kingdom (UK). The ratio of incidence i...

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... mutations is found. In Norway, mutation of the gene for AMN has been reported. Chapter 100. Megaloblastic Anemias (Part 9) Serum Antibodies Two types of IF immunoglobulin G antibody may be ... Congenital Cobalamin Malabsorption; Autosomal Recessive Megaloblastic Anemia, MGA1) This autosomally recessive disease is the most common cause of megaloblastic anemia due to cobal...

Ngày tải lên: 07/07/2014, 04:20