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At least 397 records · Page 22Linked to original sources
PubMed1995

Thrombopoietin is not responsible for the thrombocytosis observed in patients with acute myeloid leukemias and the 3q21q26 syndrome.

Patients with acute myeloblastic leukaemia (AML) and chromosomic abnormalities of the 3q21;q26 region have striking dysmegakaryopoiesis and normal or increased platelet counts. Leukaemic cells ectopically express the Evi-1 gene which maps to human chromosome 3q26:q27. Thrombopoietin (TPO) has been cloned recently and shown to be the major hormone stimulating both megakaryocytopoiesis and thrombopoiesis. The TPO gene maps to human chromosome 3q26. For this report we studied four patients with typical 3q21:q26 syndrome. Karyotype analysis showed inv(3)(q21;q26) in three cases and t(3:3)(q21;q26) in one case. Although high levels of Evi-1 transcripts could be detected in mRNA isolated from the bone marrow cells of these patients by Northern blot analysis, no TPO transcripts were detectable by RT-PCR technique on the same mRNA samples. These results demonstrate that TPO gene transcription is not activated in patients with 3q26 chromosomic abnormality, and that abnormal TPO production is not responsible for the observed thrombocytosis.

Acute Disease↗
PubMed1991

Platelet apheresis for extreme thrombocytosis in an 11-year-old girl with CML.

This report describes the dramatic reduction in the platelet count and ablation of symptoms by consecutive platelet apheresis in a young girl with CML who presented with an extremely high platelet count of 10,320 x 10(9)/l. Extreme thrombocytosis, although quite rare, can be symptomatic and life-threatening in paediatric patients and should be considered an emergency. The mechanical removal of platelets by apheresis is effective therapy and should begin as soon as possible.

Child↗
PubMed1984

Platelet glyoxalases in thrombocytosis.

In platelets of patients suffering from thrombocytosis due to myeloproliferative disorders, glyoxalase I activity is significantly higher than in controls (P less than 0.01), while glyoxalase II levels are the same (P less than 0.3). The cellular concentration of glutathione is also increased in patients. Km values for methylglyoxal (glyoxalase I) and S-lactoylglutathione (glyoxalase II) are identical both in normal and pathological subjects, as are the thermostability of the two enzymes. The higher activity observed for glyoxalase I in patients could be related to a specific role of this enzyme in platelets.

Adult↗
PubMed1988

Use of splenic volume estimation to distinguish primary thrombocythaemia from reactive thrombocytosis.

Splenic volume was measured by visual assessment of planar images of the spleen, and also by single photon emission computerised tomography (SPECT) using 99mtechnetium tin colloid, in a group of 33 patients with primary thrombocythaemia (PT) or reactive thrombocytosis. Volumes greater than 337 cm3 correlated strongly though not absolutely with PT, all patients with volumes greater than this figure being in the PT group. Simple visual assessment of planar images by an experienced observer matched measured splenic volumes very closely.

Adult↗
PubMed1994

Circulating megakaryocytic progenitor cells in patients with primary thrombocythaemia and reactive thrombocytosis: results using a serum-deprived culture assay and a positive detection technique.

A serum-free culture method was used to study the growth of megakaryocytic progenitor cells (CFU-Meg) from patients with elevated platelet counts. The culture technique was combined with immunocytochemistry (APAAP, CD61) for the identification of CFU-Meg derived cells in cytopreparations of cells eluted from the culture dishes. Twenty-six patients with primary thrombocythaemia (14 untreated patients, UPT, 12 treated patients, TPT), 14 patients with reactive thrombocytosis (RT) and 9 normal individuals were studied. Unstimulated growth of CD61-positive cells was detected in 8/14 UPT, 8/12 TPT, 12/14 RT and 5/9 normal subjects (with mean CD61-positive cell counts of 75, 579, 236 and 7 per cytopreparation respectively). Cultures supplemented with interleukin 3 contained CD61-positive cells in 11/14 UPT, 7/12 TPT, 14/14 RT and 5/9 normal subjects (with mean CD61-positive cell counts of 157, 589, 250 and 7 per cytopreparation respectively). Thus, this serum-free culture technique combined with sensitive positive identification of CFU-Meg derived cells failed to discriminate between PT and RT. These results cast doubt on the usefulness of serum-free culture assays for the detection of unstimulated CFU-Meg growth in the differential diagnosis of patients with elevated platelet counts.

Antibodies, Monoclonal↗
PubMed1998

Impact of endogenous thrombopoietin levels on the differential diagnosis of essential thrombocythaemia and reactive thrombocytosis.

By using the newly commercialized Quantikine human TPO immunoassay, plasma thrombopoietin (TPO) concentrations were measured in 12 patients with essential thrombocythaemia (ET), 13 patients with reactive thrombocytosis (RT) and 11 healthy volunteers. For the healthy volunteers the mean plasma TPO concentration was 21.1+/-11.0 pg/ml. The mean plasma TPO concentration in the group of RT was slightly lower (16.4+/-8.6 pg/ml) but did not differ significantly from the control group. The mean plasma TPO concentration in ET patients (44.1+/-45.2 pg/ml) was significantly (p<0.05) higher than the mean for RT patients, but did not differ statistically from the mean of healthy volunteers. These data suggest a defective clearance of plasma TPO in patients with ET.

Adult↗
PubMed1976

Reversible thrombocytosis and anemia due to miconazole therapy.

Miconazole was administered intravenously in six consecutive patients with, active coccidioidal infection. Such treatment was associated with progressive anemia and thrombocytosis. The hematological abnormalities appeared to be dose related and potentially reversible. Bone marrow studies demonstrated erythroid hypoplasia and increased or active platelet production in three subjects. No hemorrhagic or thrombotic episodes were identified. It is suggested that careful hematological monitoring be performed in subjects undergoing systemic miconazole therapy.

Adolescent↗
PubMed1979

Thrombocytosis in low birthweight infants: a physiological phenomenon in infancy.

Prematurity has traditionally been connected with thrombocytopenia, although this is unlikely to be associated with prematurity itself but rather with serious illnesses in such infants. Platelet counts were measured in 117 healthy preterm infants with birthweights less than 2000 g, who were followed up from 2 weeks to 6 months. In this series the platelet counts were high compared with those in previous reports, and also compared with what is considered normal for term infants. The 95% range was between 160 and 675 X 10(9)/1, with a median value of 375 X 10(9)/1. The data suggest that thrombocytosis is a phenomenon related to prematurity.

Humans↗
PubMed1979

Thrombocytosis, circulating platelet aggregates, and neurological dysfunction.

In 12 patients whose neurological dysfunction was associated with thrombocytosis or evidence of abnormal platelet activation, or both, correction of the platelet disorder corresponded with reversal of the neurological symptoms. This suggests that platelet abnormalities may, in certain cases, produce several syndromes of neurological dysfunction, presumably as a result of obstruction of the cerebral microcirculation.

Adolescent↗
PubMed1978

Polyarteritis presenting with thrombocytosis and palliated by plasma exchange.

A 66-year-old patient with polyarteritis nodosa presented with thrombocytosis and was found to have circulating immune complexes. Treatment by plasma exchange produced symptomatic improvement and lowered both the platelet count and the level of immune complexes. While plasma exchange is a useful technique in investigating the pathogenesis of the disease, predisolone is a more convenient way of treating it.

Aged↗
PubMed2000

Trisomy 14 with thrombocytosis and monocytosis.

It has been reported that trisomy 14 is associated with myeloid malignancies, but a case with increased platelet count has also been reported. However, the clinical significance of trisomy 14 is still uncertain. We report a patient with trisomy 14 with thrombocytosis and a gradual increase in monocytosis. He was treated with hydroxyurea, cytarabine and aclarubicin in low doses and his quality of life was maintained for a period of about 1 year from blastic crisis. Hydroxyurea, cytarabine or aclarubicin in low doses may be the treatment of choice for trisomy 14 patients with respect to the patients' quality of life.

Aclarubicin↗
PubMed1993

Myelodysplastic syndrome with thrombocytosis in a patient with Klinefelter's syndrome.

We report herein a patient with Klinefelter's syndrome associated with refractory anemia with excess of blasts in transformation, a subtype of myelodysplastic syndrome (MDS). The MDS developed with karyotypic abnormality involving t(4;7)(q21;q11), and was characteristic of marked thrombocytosis and marrow infiltration by many atypical megakaryocytes. The patient also had diabetes mellitus and a disturbed immune system. To our knowledge, this is the fifth reported case of MDS in patients with Klinefelter's syndrome in the literature.

Anemia, Refractory, with Excess of Blasts↗
PubMed1989

Primary (essential) thrombocythemia versus initial (hyperplastic) stages of agnogenic myeloid metaplasia with thrombocytosis--a critical evaluation of clinical and histomorphological data.

In 40 patients (17 male, 23 female, median age 57 years) with the presumptive diagnosis of primary (essential) thrombocythemia (PTH) according to the diagnostic requirements of the Polycythemia-Vera-Study-Group (PVSG) a follow-up study and a histological evaluation of initial trephine biopsies of the bone marrow were performed. Thorough review of the hematological data during the lengthy course of disease (observation time ranging from 1.5-10.5 years) and the histomorphology of the bone marrow implied a discrimination into two groups of patients. Group I patients (n = 26; 10 male, 16 female) were compatible with PTH according to our follow-up studies. Group II patients consisted of 14 cases (7 male, 7 female) which suggested retrospectively early hyperplastic stages of agnogenic myeloid metaplasia (AMM) with concomitant thrombocytosis. In PTH (group I patients) there was a sustained elevation of the platelet count lasting for several years accompanied by stable other blood values. Early AMM (group II patients) was characterized by an insidious decline of the initially elevated thrombocyte count, starting in a few patients already 4-6 months after admission. In AMM there was further an increase in hepatosplenomegaly observable together with the level of LDH and the score of the leukocyte alkaline phosphatase, and finally an evolution of a leukoerythroblastic blood picture could be noticed. Initial histopathology of the bone marrow revealed a profound proliferation of a not severely dysplastic megakaryopoiesis in group I patients (PTH) and a normal content of reticulin fibers. In early thrombocythemic AMM (group II patients) conspicuous abnormalities of megakaryocytes were accompanied by a slight to moderate increase in argyrophilic fibers and a left-shifted neutrophilic granulocyto- as well as erythropoiesis. These differences of certain histomorphological features could be substantiated by morphometric analysis. Our findings suggest that even the rigid requirements for the diagnosis of PTH as proposed by the PVSG may not be sufficiently restrictive to exclude patients with early hyperplastic stages of thrombocythemic AMM.

Biopsy, Needle↗
PubMed1987

The significance of thrombocytosis in old age.

We performed a retrospective study on 21 patients, aged 70 years or more, affected by polycythemia vera (PV) or essential thrombocythemia (ET). As controls, we evaluated 10 younger ET patients. The results indicate that in older ET subjects there was a lower incidence of hemorrhagic and thrombotic complications than in younger patients and PV patients. However, platelet number and platelet function tests were similar in all the patients studied. We suppose that an increase in hematocrit as seen in PV is much more dangerous as compared to an isolated increase in platelet count, and that thrombocytosis alone in old age can be an isolated expression of a natural involution of blood marrow similar to myelofibrosis.

Adult↗
PubMed1985

Megakaryocytopoiesis in different forms of thrombocytosis and thrombocytopenia: identification of megakaryocyte precursors by immunostaining of intracytoplasmic factor-VIII-related antigen.

Megakaryocytopoiesis was investigated with a polyclonal (26 cases) and a monoclonal (20 cases) antibody to factor-VIII-related antigen (factor VIII RAg) with the indirect peroxidase-antiperoxidase (PAP) method on air-dried bone marrow aspirates (BM). Numerous megakaryocyte precursors were identified in 5 patients with essential thrombocythemia (ET) and the 2 patients with acute myelogeneous leukaemia (AML) after recovery from therapeutic aplasia. Small megakaryocyte precursors were rare in controls (C), patients with reactive thrombocytosis (RT) and immune thrombocytopenia (IT). In 2 patients with severe alcoholism the number of mature megakaryocytes increased after 5 and 7 days of abstinence, respectively.

Antibodies, Monoclonal↗
PubMed1983

Thrombocytosis and microthrombocytosis: a clinical evaluation of 372 cases.

Data on 372 patients with thrombocytosis (TC), defined as a platelet count over 500 X 10(9)/1, were accumulated in a non-biased fashion. Surgery, per se, was a common cause of TC and malignancy, if uncomplicated by infection, bleeding or surgery, was a less common cause of TC than suggested in previous surveys. The reasons for these apparent differences are discussed. Postoperative TC resolved within 30 days of surgery in the absence of complications. Transient reactive TC due to a variety of causes was accompanied by a significant fall in platelet volume in contrast to the megathrombocytosis found in postsplenectomy and myeloproliferative TC.

Anemia, Hypochromic↗