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At least 1,297 records · Page 72Linked to original sources
PubMed1985

Platelet immune complex interaction in pathogenesis of Kawasaki disease and childhood polyarteritis.

The role of platelets in the pathogenesis of vasculitis and the formation of coronary artery aneurysms was studied in 19 children with Kawasaki disease and five with polyarteritis. All patients with Kawasaki disease developed thrombocytosis in the third week of illness. The peak platelet count was significantly correlated (p less than 0.005) with the subsequent development of coronary artery aneurysms. The rise in platelet count was associated with the appearance in the circulation of a factor that induced aggregation and serotonin release in normal platelets. This factor was shown to be of high molecular weight, and its activity was lost at low pH--features suggestive of an immune complex. Immune complexes, detected by precipitation with polyethylene glycol, also appeared in the circulation as the platelet count increased. These complexes induced platelet aggregation, and there was a significant correlation (p less than 0.001) between the concentrations of IgG and IgA in the polyethylene glycol precipitated material and the platelet aggregating activity. Similar platelet aggregating activity was also detected in patients with polyarteritis but followed a different time course, persisting in the circulation for several months in association with continued disease activity. These findings imply that different mechanisms have a role in distinct phases of Kawasaki disease. The initial feverish phase (probably infective) is probably followed by an immune complex vasculitis that occurs when antibodies to the initiating agent appear in the circulation. The immune complexes aggregate platelets and induce release of serotonin. Platelet derived vasoactive mediators may increase vascular permeability and facilitate further deposition of complexes in the tissues.

Aneurysm↗
PubMed2006

[Evaluation of V617F mutation of JAK2 in negative chromosome Philadelphia chronic myeloproliferative disorders].

BACKGROUND AND OBJECTIVE: Polycythemia vera (PV) and essential thrombocytemia (ET) are chronic myeloproliferative diseases (MPD) characterized by overactive hemopoiesis. A single point mutation of JAK2 (Val617Phe) has been detected in PV, ET and myelofibrosis (MF). The aim of this work was to investigate the JAK2 mutation in patients with MPD and to compare the results to those of the endogenous formation of BFU-E erythroid colonies (EEC). Finally, different sources of hematopoietic cells to obtain DNA were evaluated. PATIENTS AND METHOD: In this work 146 patents were studied (81 MPD: 27 PV, 28 ET, 11 MF and 15 with myeloid chronic leukemia). Moreover, 28 patients showed secondary polycythemias or reactive thrombocytosis, 8 MPD/myelodysplastic syndromes and 29 other disorders. In 54 patients, EEC were also evaluated. Peripheral blood cells were used as source of DNA in 122 patients, bone marrow in 33, cells from BFU-E in 14 and cells from EEC in 24 patients. Their DNA samples were analyzed using an allele-specific polimerase chain reaction methodology. RESULTS: The JAK2 mutation was present in 96% of PV patients, 59% of ET and 63.6% of MF. None of the remaining patients showed this mutation. Diagnostic agreement was excellent between EEC and the mutation (kappa index = 0.93; 97% positive agreement and 95% negative agreement). DNA was obtained in 119 out of 122 samples from peripheral blood, in all patients with bone marrow, and in 50% of patients with BFU-E or EEC. In 7 cases, samples from different cell sources were studied. Their results were identical. CONCLUSIONS: The V617F mutation of JAK2 is present in most of PV patients and half of those with MF or ET. There is an excellent concordance with the EEC results.

DNA↗
PubMed1998

Changes in serum thrombopoietin levels after splenectomy.

To clarify the role of thrombopoietin (c-Mpl ligand, TPO) in 'hypersplenic' thrombocytopenia, we used an enzyme-linked immunosorbent assay to examine changes in serum TPO levels accompanied with splenectomy in 6 patients with liver cirrhosis, 4 patients with gastric cancer, and 2 patients with lymphoid malignancies. We also measured serum levels of other thrombopoietic cytokines such as interleukin-6 (IL-6) and erythropoietin. Platelet counts reached a maximum at day 14 after splenectomy in all subjects. In patients with liver cirrhosis, a lower elevation of platelet counts was observed compared with that in patients with gastric cancer. Serum TPO levels gradually elevated after splenectomy and reached a maximum 3.5 days after splenectomy in noncirrhotic patients, whereas peak serum TPO levels were delayed until day 7 in the cirrhosis group. IL-6 and erythropoietin showed similar kinetics between cirrhotic and noncirrhotic patients. These findings suggest that transient thrombocytosis after splenectomy may be associated with an alteration in the site of TPO catabolism by platelets from spleen to the blood and that deterioration of TPO production may play a role in thrombocytopenia in liver cirrhosis.

Adult↗
PubMed2001

Increment of the platelet count in temporal arteritis: response to therapy and ischemic complications.

Temporal arteritis (TA) is a vasculitis involving mainly cranial branches of the aorta that can lead to ischemic complications such as amaurosis or ischemic stroke. Increment in the platelet count has been described in the acute period of the disease. We studied retrospectively the platelet count in patients with TA, its association with ischemic complications and quantified its response to therapy. We found thrombocytosis in 44% of 34 patients with TA, with a mean reduction in the platelet count of 25.1% after therapy. We were also able to quantify the increment in the platelet count at the onset of the disease and its response to prednisone in a group of 5 patients. We did not find any relation between platelet count and ischemic complications of the disease or the result of the temporal artery biopsy. In conclusion TA is associated with an increase in the platelet count, with a 25% reduction after prednisone therapy. These two determinations are not related to ischemic complications of the disease.

Aged↗
PubMed1989

Danazol and internal carotid artery thrombosis.

The case of a 47-year-old woman suffering from a CT-assessed ischemic right hemisphere stroke, which occurred after a 2-month treatment with danazol (a synthetic androgen), is reported. The patient's thrombocytosis in association with danazol treatment and its possible correlations with the thrombotic event are discussed.

Carotid Artery Thrombosis↗
PubMed1991

Interleukin-6-producing pheochromocytoma.

A 42-year-old female with high fever and headache was admitted. Physical examination revealed hypertension, thrombocytosis with megakaryocytosis, hyperfibrinogenemia, and high level of serum noradrenaline. After operation of extramedullary pheochromocytoma, all symptoms disappeared and findings became normal. The supernatant of tumor culture showed high levels of interleukin-6.

Adrenal Gland Neoplasms↗
PubMed1987

Spontaneous formation of megakaryocyte progenitors (CFU-MK) in primary thrombocythaemia.

An improved plasma clot culture method for CFU megakaryocytes (MK) has been developed with a higher plating efficiency and easier identification and enumeration of MK colonies by an indirect immunoperoxidase staining using a monoclonal antibody specific to the platelet glycoprotein IIb/IIIa complex. This technique has been used to study megakaryocytopoiesis in 20 normal individuals, 4 recently diagnosed patients with untreated primary thrombocythaemia (PT) and 2 patients with secondary thrombocytosis (ST). An increased number of MK colonies was evident in peripheral blood (mean 115 +/- 31 CFU-MK/5 X 10(5) seeded cells or 206 +/- 91/ml) and to a lesser extent in bone marrow (mean 188 +/- 26 CFU-MK/5 X 10(5) seeded cells or 696 +/- 103/ml) of PT patients as compared to controls (mean 11 +/- 4/5 X 10(5) seeded cells or 13 +/- 3/ml of peripheral blood and 153 +/- 15/5 X 10(5) seeded cells or 319 +/- 43/ml of bone marrow). There was a very obvious difference between PT patients and the others (controls plus ST patients) because CFU-MK growth with no added stimulus (PHA-LCM or PHA-LCM and normal serum) could be seen in PT patients only.

Blood Cells↗
PubMed1980

Hematological abnormalities in scleroderma. A study of 180 cases.

Hematological abnormalities in scleroderma indicate a specific complication of the disease itself, or an associated illness. Among 180 patients with scleroderma, anemia was detected in 25% and was attributed to chronic inflammatory disease (usually an overlap syndrome), bleeding mucosal telangiectases as part of the CREST syndrome, intestinal malabsorption, and microangiopathic hemolysis. Leukocytosis, present in 14%, was correlated with active myopathy and/or advanced visceral involvement while leukopenia was suggestive of a crossover with systemic lupus erythematosus. Thrombocytopenia was often a manifestation of microangiopathy, and thrombocytosis was associated with an arteritis or a tumor syndrome.

Anemia↗
PubMed1977

Chronic myelogenous leukemia with elevated leukocyte alkaline phosphatase, positive indirect Coombs' test, neutrophilic leukocytosis and unusual cytogenetical findings.

An unusual case of chronic myelogeous leukemia (CML) is reported which was characterized by leukocytosis without a shift to the left, elevated leukocyte alkaline phosphatase, positive indirect Coombs' test, anemia and thrombocytosis, as well as the absence of hepatosplenomegaly. The diagnosis of CML was ascertained by the presence of Philadelphia chromosome with translocation of its deleted arms on the short arms on the short arms of a chromosome No. 6. The possible relationship between the chromosomal aberration and the unusual hematological and clinical features of this case is discussed.

Adult↗
PubMed1980

Clotting changes in two patients with longitudinal sinus thrombosis.

Two patients with angiographically proven longitudinal sinus thrombosis were studied from a coagulation point of view. In the first case, marked primary thrombocytosis was found. This patient was treated with aspirin, dipyridamole and radioactive phosphorus. In the second case, fibrinogen and whole blood plasma viscosity were elevated. This patient developed deep vein thrombosis of the left leg a few weeks after the cerebral episode and was treated with coumarin drugs. The importance of a coagulation study in every patient with cerebral vein thrombosis is emphasized.

Adult↗
PubMed1992

Histiocytic lymphophagocytic panniculitis (Rosai-Dorfman disease): a case report.

A 68-year-old woman presented with a symmetrical enlargement of the face and submandibular area associated with essential thrombocytosis. Biopsy of the lesions revealed a septal and lobular panniculitis disclosing a lymphohistiocytic and plasma cell proliferation with lymphophagocytosis by histiocytes, compatible with Rosai-Dorfman disease. The lesions regressed spontaneously without therapy over a period of 4 months. Diagnosis was confirmed by electron-microscopic examination and immunocytochemical presence of S-100 antigen within the histiocytic cells. A 2-year follow-up did not demonstrate any evidence of recurrence.

Aged↗
PubMedDate not supplied

Leukocytosis in rabbits with diet-induced atherosclerosis.

In cholesterol-fed rabbits the extent of monocyte involvement in atherogenesis may be influenced by the level of circulating leukocytes during hypercholesterolemia. We characterized the leukocytosis in rabbits fed either a 0.25% or a 0.1% cholesterol-enriched diet (0.25% or 0.1% rabbits, respectively). Circulating leukocytes were elevated by 1 week of feeding, and the elevation was sustained for at least 30 weeks. Differential counts were unchanged. Immature leukocytes were not seen, indicating that the leukocytosis was not due to premature release of bone marrow cells. Animals were free of bacterial or parasitic disease; selected rabbits with leukocytosis had normal body temperatures. Spleen weights averaged at least 100% higher in 0.25% rabbits but did not show histological evidence for hematopoiesis that could account for the leukocytosis. At approximately 22 weeks there was a second rise in leukocytosis in bilirubinemic 0.25% rabbits, suggesting that in the late stages of hypercholesterolemia, leukocytosis is related to liver failure. Cholesterol-fed rabbits also showed thrombocytosis. Existing leukocytosis and hypercholesterolemia were reversed to pretreatment levels by switching the rabbits to chow diets. In bone marrow from 0.25% rabbits, the mean number of cells per gram was greater (p less than 0.05) than that from normocholesterolemic rabbits. In 0.25% rabbits, the fraction of blood mononuclear cells showing phagocytosis of immunoglobulin G-coated red blood cells did not differ from that of controls, suggesting an unchanged population of these cells with regard to Fc and phagocytic function during hypercholesterolemia. These data suggest an effect (direct or indirect) of hypercholesterolemia on the production of leukocytes in the bone marrow and/or on the circulation kinetics of leukocytes in the blood.

Animals↗
PubMed1993

The effects of olive oil, hydrogenated palm oil, and omega-3 fatty acid-enriched diets on megakaryocytes and platelets.

Unsaturated fatty acids are thought to prevent thrombotic and arteriosclerotic disease, whereas saturated fatty acids are thought to increase the incidence of these disorders. However, the effects of these diets on megakaryocytes and platelets are not well understood. We compared the effects of diets enriched with 8.4% olive oil, 8.4% hydrogenated palm oil, or 10.2% omega-3 fatty acid ethyl esters on guinea pig megakaryocytes and platelets. In plasma, changes in fatty acid composition reflected the composition of each diet. However, in platelets and megakaryocytes, hydrogenated palm oil induced a decrease in 16:0 and an increase in 18:2 while the olive oil diet caused a marked increase in 18:1 and a decrease in most other fatty acids. The differences in the effects of the diets on cellular versus plasma fatty acids suggest that megakaryocytes and platelets have an extensive capacity to regulate their fatty acid composition. Thrombocytosis occurred with the omega-3 fatty acid-enriched diet: 12.9 +/- 1.78 x 10(5) compared with 7.45 +/- 1.08 x 10(5) platelets per microliter of platelet-rich plasma in control animals. There was an increase in megakaryocyte size, ploidy, and morphological stage (cytoplasmic maturation) with the omega-3 fatty acid-enriched diet but not with the other diets. The omega-3 fatty acid-enriched diet decreased platelet thromboxane production while the other diets had no effect. Platelet hypersensitivity was suggested in collagen aggregation studies with olive oil but not with the hydrogenated palm oil diet. Although saturated fatty acid diets are thought to be atherogenic, this diet had no affect on platelet function.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1968

Kinetics of thrombopoiesis.

Measurements of megakaryocyte number, volume, nuclear number, and cytoplasmic granulation were compared in animals with induced thrombocytosis, normal platelet counts, and induced thrombocytopenia for 4- and 10-day periods. Thrombopoiesis, as measured by megakaryocytic mass and (35)S incorporation into platelets, appeared to be regulated by the demand for circulating platelets. In addition, two mechanisms were operative in the alteration of thrombopoiesis. The first mechanism involved the regulation of endomitosis in the immature megakaryocytes which in turn determined the subsequent volume of platelet-producing cytoplasm. The second mechanism regulated the number of megakaryocytes formed from the precursor, "stem cell," compartment.

Animals↗
PubMed1969

Measurement of thrombopoiesis in rabbits using 75selenomethionine.

Incorporation of (75)selenomethionine ((75)SeM) has been used to study platelet production in rabbits. Radioactivity of platelets was low after the intravenous administration of (75)SeM and rose to a maximum approximately 3 days after administration. Platelet radioactivity was independent of concurrent plasma levels. The life span of rabbit platelets, as estimated with this technique, was 4-5 days. In vivo reutilization of (75)SeM previously incorporated into plasma proteins was not detected. In vitro incorporation of (75)SeM by platelets in platelet-rich plasma was not demonstrated. Acute hemorrhage 24 hr before administration of (75)SeM increased the incorporation of (75)SeM into platelets. Transfusion-induced thrombocytosis reduced the incorporation of (75)SeM to approximately 30% of that observed in control animals. Suppression of bone marrow function with nitrogen mustard resulted in decreased numbers of platelets in the circulation, and a decrease in incorporation of (75)SeM. Delayed appearance of (75)SeM was observed in circulating platelets during recovery from marrow suppression. Injection of 75-225 ml of plasma from thrombocytopenic donors into normal rabbits increased incorporation of (75)SeM into platelets while normal plasma did not have this effect. The rate of appearance of (75)SeM in circulating platelets appears to provide a sensitive and specific method for the study of production of platelets by megakaryocytes. The data suggest more rapid entry of platelets into the circulation, and a sustained increase in incorporation of (75)SeM into platelet protein after stimulation of platelet production. The results are consistent with the concept of a humoral agent (thrombopoietin) that acts on megakaryocytes to regulate platelet production.

Animals↗
PubMed1985

Philadelphia chromosome-positive chronic myelogenous leukemia following apparent acute lymphoblastic leukemia.

The observation that Philadelphia chromosome-positive acute lymphoblastic leukemia (ALL) may progress to chronic myelogenous leukemia (CML) has been well-documented among adult patients but reported only rarely in children. In this report, we describe a pediatric patient with atypical ALL, who subsequently went on to develop classical adult-type CML. This patient is unique and important because of the unusual clinical findings that she exhibited during the "ALL" phase, namely, extreme thrombocytosis, marrow fibrosis, and persistent splenomegaly, which heralded the onset of frank CML. It is suggested that the patient with presumed, but atypical, ALL be carefully evaluated for CML presenting in lymphoblastoid crisis, and that all patients with the morphologic diagnosis of ALL undergo complete cytogenetic and immunologic marker studies to confirm the diagnosis.

Bone Marrow↗
PubMedDate not supplied

Alpha interferon as initial treatment of essential thrombocythemia. Analysis after two years of follow-up.

AIMS AND BACKGROUND: Recombinant alpha-interferon has been shown to be effective in essential thrombocythemia and in thrombocytosis associated with other myeloproliferative disorders. PATIENTS AND METHODS: Twenty-five untreated patients were enrolled in our study from May 1989 to April 1992. Recombinant alpha interferon-2b was administered at an initial dose of 2 megaunits (MU)/m2 three times a week at escalating doses to 5 MU/m2 or the maximum tolerated dose. The mean follow-up for patients still in treatment at the time of this report was 35.9 months (range, 24-63). RESULTS: Fourteen patients (56%) had achieved a complete remission by a mean time of 152 days; 6 patients (24%) had achieved a good partial remission by a mean of 180 days. In addition to the favorable effect on platelet count, a marked improvement in clinical symptoms was observed. Treatment had to be discontinued in 9 patients (36%), 5 for toxicity (3 neurologic, 1 anemia and 1 severe hypertriglyceridemia) at a median of 155 days from the beginning of therapy (range, 30-400). Four patients refused to continue therapy because of low tolerance (flu-like syndrome) at mean of 160 days from the beginning of therapy (range, 34-301). CONCLUSIONS: In our study, lower doses were administered compared with previous short-time trials. The present data show that interferon is an effective alternative to cytostatic agents in long-term treatment of patients with essential thrombocythemia, even when used at lower dosages.

Adult↗
PubMed2002

Discrimination of polycythemias and thrombocytoses by novel, simple, accurate clonality assays and comparison with PRV-1 expression and BFU-E response to erythropoietin.

Essential thrombocythemia (ET) and polycythemia vera (PV) are clonal myeloproliferative disorders that are often difficult to distinguish from other causes of elevated blood cell counts. Assays that could reliably detect clonal hematopoiesis would therefore be extremely valuable for diagnosis. We previously reported 3 X-chromosome transcription-based clonality assays (TCAs) involving the G6PD, IDS, and MPP1 genes, which together were informative in about 65% of female subjects. To increase our ability to detect clonality, we developed simple TCA for detecting the transcripts of 2 additional X-chromosome genes: Bruton tyrosine kinase (BTK) and 4-and-a-half LIM domain 1 (FHL1). The combination of TCA established the presence or absence of clonal hematopoiesis in about 90% of female subjects. We show that both genes are subject to X-chromosome inactivation and are polymorphic in all major US ethnic groups. The 5 TCAs were used to examine clonality in 46 female patients along with assays for erythropoietin-independent erythroid colonies (EECs) and granulocyte PRV-1 mRNA levels to discriminate polycythemias and thrombocytoses. Of these, all 19 patients with familial polycythemia or thrombocytosis had polyclonal hematopoiesis, whereas 22 of 26 patients with clinical evidence of myeloproliferative disorder and 1 patient with clinically obscure polycythemia were clonal. Interestingly, interferon alpha therapy in 2 patients with PV was associated with reversion of clonal to polyclonal hematopoiesis. EECs were observed in 14 of 14 patients with PV and 4 of 12 with ET, and increased granulocyte PRV-1 mRNA levels were found in 9 of 13 patients with PV and 2 of 12 with ET. Thus, these novel clonality assays are useful in the diagnosis and follow-up of polycythemic conditions and disorders with increased platelet levels.

Adolescent↗