Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0032463 (polycythemia vera)
 3,374 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recently new radioimmunoassay methods have been established to measure plasma concentrations of beta-thromboglobulin (beta-TG) and platelet factor 4 (PF4), platelet release products which are set free when platelets aggregate. Plasma concentrations of beta-TG and PF4 were investigated in disorders with increased thromboembolic risk. Extremely high concentrations of these platelet proteins were found in patients with venous thrombosis, pulmonary embolism, polycythemia vera, and chronic renal failure. Moderately increased beta-TG and PF4 levels were observed in patients with peripheral vascular disease, coronary artery disease, chronic rheumatoid arthritis, multiple myeloma, and diabetes mellitus. These data indicate, that plasma concentrations of beta-TG and PF4 are useful parameters for the evaluation of the "in vivo" platelet activity. By using these new methods for clinical applications special blood sampling conditions have been taken into account; moreover one has to consider that the plasma levels of the platelet "release products" are dependent from renal function.
 ...
PMID:[Clinical significance of the radioimmunological determination of beta-thromboglobulin and platelet factor 4]. 9 43

We examined the conditions necessary for performing a reliable erythropoietin (EPO) assay based on CFU-E colony formation in fetal mouse liver cell (FMLC) microcultures using 96-well microtiter plates. Both linearity of colony numbers with the number of cells plated and comparison among the colony ratios at various densities of seeding cells indicated that the colonies originated from a single progenitor cell when 7500 or fewer cells were plated into individual microtiter wells. About a twofold CFU-E enrichment in 12- to 13-day FMLC was achieved by Ficoll-Paque centrifugation. Plasma treated with acid-boiling stimulated the colony formation most and contained no colony inhibitor. Dose-response curve for the plasma was parallel to the EPO standard curve. The "erythroid colony-stimulating activity" in the plasma was additive to that in the standard EPO, and was completely neutralized by a monoclonal antibody against recombinant human EPO. Using the assay procedure thus established, plasma EPO titer was determined in normal subjects, in patients with nonuremic anemia and polycythemia vera, and in dialysis patients with chronic renal failure. The use of different preparations of standard EPO resulted in a significant difference in the titers because their dose-response curves differed from one another. An inverse relationship was found between EPO titers and hemoglobin concentrations in the nonuremic anemic patients, but not in the dialysis patients with about one half the normal EPO level.
 ...
PMID:Improved microbioassay for plasma erythropoietin based on CFU-E colony formation. 162 57

Splenic erythropoiesis was demonstrated by surface counting of 59Fe in 129 of 1,350 ferrokinetic studies performed over a 15 year period. These 129 studies were carried out in 108 patients, including 40 with chronic myelogenous leukemia (CML), 24 with agnogenic myeloid metaplasia (AMM), 18 with polycythemia vera (PV), six with a myelodysplastic syndrome, five with acute leukemia, three with prostate or breast carcinoma, two each with aplastic anemia or Hodgkin's disease, and one each with idiopathic thrombocythemia, multiple myeloma, chronic renal failure, or treated hypopituitarism. Splenomegaly was present in 83% of the studies and hepatomegaly in 72%. Grade II-III myelofibrosis was demonstrated in 62% of the cases. Hepatic erythropoiesis was present in 77% of the studies (only 38% in PV), and marrow erythropoiesis was undetectable in 33%. Total erythropoiesis was about twice normal (range 0.2 to 8 times normal) but was ineffective to varying degrees in 86% of the studies. Relationships between organomegaly, myelofibrosis, and extramedullary erythropoiesis, as well as differences among clinical disorders, are discussed. Differences observed between CML in chronic or blastic phase suggested that the erythroid cell line was involved in the proliferative process. It is concluded that splenic erythropoiesis 1) is encountered in a variety of clinical conditions; 2) is not necessarily associated with splenomegaly or myelofibrosis, even in the myeloproliferative disorders; 3) is part of a predominantly extramedullary (in the liver as well as in the spleen), expanded, and largely inefficient total erythropoiesis; and 4) can be evaluated in a semiquantitative manner by surface counting.
 ...
PMID:Ferrokinetic study of splenic erythropoiesis: relationships among clinical diagnosis, myelofibrosis, splenomegaly, and extramedullary erythropoiesis. 275 9

Out of 2,474 bone marrow biopsies we have observed 330 cases (13.3%) with presence of lymphoid nodules (LN). LN were frequent in old age (24.6% over 80 years), in females (17%) and in some diseases, such as rheumatoid arthritis and systemic lupus erythematosus (73.7% of the cases), partial aplasia (34%), hypersplenism (30.4%), hemopoietic dysplasia (25%), chronic renal failure (20.4%), polycythemia vera (20.2%), idiopathic thrombocytopenic purpura (18.8%), acute leukemia (17.7%). Nodular lymphoid hyperplasia of the bone marrow was found especially in systemic autoimmune diseases (26.3%), hypersplenism (9.8%), preleukemia (7.3%) and acute leukemia (4.2%). The presence of excessive medullary LN could indicate a bone marrow microenvironment damage, possibly of autoimmune origin.
 ...
PMID:Lymphoid nodules and nodular lymphoid hyperplasia in bone marrow biopsies. 393 2

Bioassays for human erythropoietin are cumbersome, time-consuming, and insensitive. The purification of human erythropoietin (EP) had provided small quantities of highly bioactive EP (approximately 70,000 U/mg) required for the development of an EP radioimmunoassay (RIA). The RIA for EP described in this investigation, can detect 5 mU/ml of EP in the assay tube; the serum concentration of EP in normal individuals ranged from less than 18 to 81 mU/ml with a mean value of 29 mU/ml. In contrast, nine patients with severe aplastic anemia had markedly elevated serum EP concentrations with a mean value of 3,487 mU/ml, range 984--6,434 mU/ml. In this RIA, patients with Polycythemia vera had consistently undetectable EP concentrations, less than 18 mU/ml. Eleven patients with chronic renal failure had a higher mean serum EP concentration (40.5 mU/ml) than normal individuals, but the range (less than 18-115 mU/ml) overlapped that of normals. By immunologic and gel chromatographic criteria, EP measured in serum was similar to standard urinary EP. The EP immunoassay that we have developed has sufficient sensitivity and specificity not only to quantitate the elevated serum EP levels found in aplastic anemia but also to discriminate decreased from normal serum concentrations of EP in most circumstances. This simple, reliable RIA has provided the necessary framework upon which to increase our understanding of the importance of EP in hematopoiesis.
 ...
PMID:Serum concentrations of erythropoietin measured by radioimmunoassay in hematologic disorders and chronic renal failure. 727 May 48

The myeloproliferative disorders (MPDs) are clonal disorders of the hematopoietic stem cell and classified as polycythemia vera (PV), essential thrombocythemia (ET), or agnogenic myeloid metaplasia (AMM), depending on the main hematopoietic lineage involved. Primary renal parenchymal lesions are not commonly reported in these cases. We conducted a retrospective analysis of 138 consecutive patients with MPD to determine the frequency of renal parenchymal complications. Five patients (3.6%) (two PV, two ET, one AMM) were found to have focal segmental glomerulosclerosis (FSGS) and diffuse mesangial sclerosis, presenting as proteinuria in all the cases and progressing to chronic renal failure in two cases. A possible common risk factor was a high platelet count, because abnormal platelet activation in MPD has been shown to contribute to the development of glomerulosclerosis. The pathophysiologic basis of our observations and the implications in management of MPD patients remain to be studied.
 ...
PMID:Focal segmental glomerulosclerosis and mesangial sclerosis associated with myeloproliferative disorders. 1056 Nov 46

IgA nephropathy (IgAN) is one of the most frequent forms of glomerulonephritis (GN). However, its association with polycythemia vera (PV) has rarely been described. We report a case of IgAN combined with PV. The patient was a 46-year-old male with chronic renal failure, heavy proteinuria and erythrocytosis. He also presented hypertension and hematuria as well as splenomegaly, high arterial oxygen saturation and elevated leukocyte alkaline phosphatase activity. Possible causes of secondary erythrocytosis were ruled out. The renal biopsy revealed mesangial proliferative GN with predominant IgA deposition in mesangium. He was diagnosed as having IgAN and PV concomitantly. After administration of hydroxyurea, enalapril and felodipine, blood cell count and blood pressure normalized, while azotemia persisted. There was also a partial remission of the heavy proteinuria. We describe a case of IgAN associated with PV, and possible pathophysiologic relationships between two diseases are discussed with review of the literature.
 ...
PMID:IgA nephropathy in a patient with polycythemia vera. Clinical manifestation of chronic renal failure and heavy proteinuria. 1216 77

Pseudohyperkalemia is defined as a serum potassium concentration 0.4 mEq/l greater than the plasma concentration. The basis of this phenomenon is the release of intracellular potassium from platelets, leukocytes, or erythrocytes, commonly in the setting of extreme leukocytosis (> 10 x 10(4)/microl) or thrombocytosis (> 60 x 10(4)/microl). We report a case of pseudohyperkalemia in a patient with chronic renal failure and polycythemia vera without the finding of severe leukocytosis or thrombocytosis (white blood cell count 1.88 x 10(4)/microl and platelet count 37.9 x 10(4)/microl, respectively). The serum potassium concentration was 8.2 mEq/l, while the plasma potassium level was 6.4 mEq/l in a sample obtained simultaneously. The concentrations of platelet factor IV and beta-thromboglobulin, known to be markers of platelet activation, were greater than 100 ng/ml and 200 ng/ml, respectively, indicating that platelet activation may have been related to the development of pseudohyperkalemia in this patient. These findings suggest that pseudohyperkalemia should be considered when hyperkalemia is seen in a patient with chronic renal failure and myeloproliferative disorders.
 ...
PMID:Pseudohyperkalemia occurring in a patient with chronic renal failure and polycythemia vera without severe leukocytosis or thrombocytosis. 1250 68

Ultraviolet-based therapy has been used to treat various pruritic conditions including pruritus in chronic renal failure, atopic dermatitis, HIV, aquagenic pruritus and urticaria, solar, chronic, and idiopathic urticaria, urticaria pigmentosa, polycythemia vera, pruritic folliculitis of pregnancy, breast carcinoma skin infiltration, Hodgkin's lymphoma, chronic liver disease, and acquired perforating dermatosis, among others. Various mechanisms of action for phototherapy have been posited. Treatment limitations, side effects, and common dosing protocols are reviewed.
 ...
PMID:Ultraviolet phototherapy for pruritus. 1629 8

Erythropoietin (EPO) is the principal haematopoietic growth factor of the red blood cell line. Its major role is to stimulate the red blood cell production. EPO synthesis by peritubular cells in the kidney is regulated by oxygen concentration and must lead adaptation of the organism to face many different physiological situations. An imbalance can lead either to anaemia or polycythemia. Synthetic EPO, so-called recombinant, has definitively changed the treatment in the anaemia of chronic renal failure and regularly find new indications, legal (anaemia of cancer, anaemia of chronic inflammatory syndromes, myelodysplastic syndromes, neurology, cardiology...) or illegal (doping substance in sport). This article reviews the physiology, the role and the indications of EPO in clinical routine practice and define why and how EPO should be measured. We also focus on the analytical requirements for serum EPO concentration determination, especially in the differential diagnosis of polycythemias (secondary polycythemia/Polycythemia Vera).
 ...
PMID:[Erythropoietin: indications and measurement]. 1978 22


1 2 Next >>