Thyroid Peroxidase (TPO), a dimeric, membrane-bound glycoprotein found in the thyroid follicular lumen, catalyses the biosynthesis of thyroxine, and is also a major autoantigen in autoimmune thyroid disease (AITD). TPO molecules undergo posttranslational modifications such as glycosylation, heme incorporation, dimer formation, and proteolytic processing in the N-terminal region. Due to propepti...

OBJECTIVES To assess the significance of thyroid autoimmune screening in alopecia areata (AA) patients in Saudi population, and to determine whether there is a difference in thyroid autoimmune susceptibility between mild and severe AA. METHODS In a prospective case-control study, we included 50 alopecia totalis (AT) and alopecia universalis (AU) patients, 50 age- and gender-matched patients w...

Thrombopoietin (TPO) was evaluated for efficacy in a placebo-controlled study in rhesus monkeys with concurrent administration of either granulocyte/macrophage colony-stimulating factor (GM-CSF) or granulocyte CSF, (G-CSF). Rhesus monkeys were subjected to 5 Gy total-body irradiation (TBI), resulting in 3 weeks of profound pancytopenia, and received either TPO 5 microg/kg intravenously (I.V.) a...

Thrombopoietin (TPO) has recently been cloned and shown to regulate megakaryocyte and platelet production by activating the cytokine receptor c-mpl. To determine whether TPO is the only ligand for c-mpl and the major regulator of megakaryocytopoiesis, TPO deficient mice were generated by gene targeting. TPO-/- mice have a >80% decrease in their platelets and megakaryocytes but have normal level...

Thrombopoietin (TPO) regulates megakaryopoiesis and platelet production. In the adult, TPO is mainly produced by the liver and the kidneys. This study focuses on fetal and neonatal TPO mRNA expression. In 26 human fetuses and preterm neonates, samples from liver, kidney, spleen, lung, and bone marrow were extracted for total RNA. We measured platelet counts, TPO serum concentrations by enzymeli...

Thrombopoietin (TPO) isolated from thrombocytopenic plasma of various animal species has previously been shown to comprise only truncated forms of the molecule, presumably generated by proteolysis. Native TPO has now been partially purified from normal human plasma by immunoaffinity chromatography and was confirmed to be biologically active. Gel filtration in the presence of SDS revealed that T...

Multiple lines of evidence indicate that thrombopoietin (TPO) contributes to the development of hematopoietic stem cells (HSC), supporting their survival and proliferation in vitro. To determine whether TPO supports the impressive expansion of HSC observed following transplantation, we transplanted normal marrow cells into lethally irradiated Tpo(-/-) and Tpo(+/+) mice and quantified HSC self-r...

Thrombopoietin (TPO), originally described as an activity in the serum of thrombocytopenic animals that leads to increased production of platelets, has recently been isolated and cloned. Its closest relative in the cytokine superfamily, erythropoietin (EPO), is transcriptionally regulated during anemia, and it was expected that TPO would similarly be regulated during thrombocytopenia. We induce...

BACKGROUND Data from several studies support the hypothesis that thrombopoietin (TPO) plasma levels are regulated via circulating platelet (PLT) numbers by binding to PLT TPO receptors (TPO-Rs). In this study, PLT numbers and TPO plasma levels were measured following the transfusion of unmanipulated, sham-saturated, and TPO-R-saturated PLT preparations to provide additional in vivo evidence for...

Thrombopoietin (TPO) regulates megakaryopoiesis and platelet production. In the adult, TPO is mainly produced by the liver and the kidneys. This study focuses on fetal and neonatal TPO mRNA expression. In 26 human fetuses and preterm neonates, samples from liver, kidney, spleen, lung, and bone marrow were extracted for total RNA. We measured platelet counts, TPO serum concentrations by enzyme-l...