1/22. The platelets in preleukemia and myelomonocytic leukemia. Ultrastructural cytochemistry and cytogenetics.light and electron microscopic studies of platelets from 16 patients with myelomonocytic leukemia or "preleukemia" revealed major morphologic alterations in 15 and minor ones in 1. Although variable in severity from case to case, the changes present followed a distinct pattern. In most cases there were two platelet populations, one morphologically normal and one morpholigically abnormal. The most salient changes pertained to size (giant forms), shape (the platelets being rounded and probably spheroidal), decrease or absence of the microtubules, and increase in immature elements. A striking feature was the variation in size and shape of the granules, with truly giant forms (up to 2.5 mum) being present. In cytogenetic studies in 14 cases, there was no correlation between the chromosomal changes and the various types of platelet anomalies.- - - - - - - - - - ranking = 1keywords = giant (Clic here for more details about this article) |
2/22. Sebastian platelet syndrome: two Japanese families originally diagnosed with May-Hegglin anomaly.Ultrastructural studies of granulocytes were performed on two unrelated patients with hereditary thrombocytopenia, giant platelets, and inclusion bodies in granulocytes. Each patient had been diagnosed with May-Hegglin anomaly. In both cases, inclusion bodies in granulocytes consisted of clusters of ribosomes and small segments of rough endoplasmic reticulum. Additional clinical features suggesting Alport syndrome were lacking in these propositi and their family members. These observations imply that the patients were affected not with May-Hegglin anomaly but with Sebastian platelet syndrome. They would thus represent the seventh and eighth families known to carry this hereditary disease.- - - - - - - - - - ranking = 0.5keywords = giant (Clic here for more details about this article) |
3/22. paris-Trousseau syndrome platelets in a child with Jacobsen's syndrome.The thrombocytopenia in an infant with clinical features of Jacobsen's syndrome characterized by multiple congenital anomalies, cardiac defects, psychomotor retardation, and deletion of chromosome 11 at 11q23.3 has been evaluated. Study of his platelets in the electron microscope revealed giant alpha granules in his cells identical in appearance to those reported in the family with paris-Trousseau syndrome. As a result, the paris-Trousseau syndrome appears to be a variant of the Jacobsen syndrome, and the thrombocytopenia observed in all cases of chromosome 11q23.3 deletion due to dysmegakaryopoieses. Giant alpha granules are frequently observed in normal platelets during long-term storage and may form in Jacobsen and paris-Trousseau platelets during prolonged residence in the bone marrow.- - - - - - - - - - ranking = 0.5keywords = giant (Clic here for more details about this article) |
4/22. Spontaneous platelet aggregation with congenital giant platelet containing large granules and thick membrane.Inherited giant platelet disorders are a heterogeneous group of disorders. In the current study, a patient was reported with moderate bleeding tendency, giant platelets, and spontaneous platelet aggregation, which were not affected by the administration of aspirin or ticlopidine. The electron microscopy of platelets showed a black and thick plasma membrane with crystal-like fine hairs in the exterior coat and more large and variously shaped granules in the cytoplasm. The expression of glycoprotein (GP) Ib, GP IIb, and GP IIIa on platelet surface was normal, and no mutations in genes for GP Ib alpha, GP Ib beta, and GP IX were detected. These phenomena are so distinguishable from those of Mondreal platelet syndrome and other hereditary giant platelet disorders, that we propose that this patient probably has a novel platelet disorder, which has not yet been reported.- - - - - - - - - - ranking = 3.5keywords = giant (Clic here for more details about this article) |
5/22. Hereditary giant platelet syndrome. Absence of collagen-induced coagulant activity and deficiency of factor-XI binding to platelets.The platelets from two related patients with the hereditary giant platelet syndrome were examined. They were larger than normal but otherwise ultrastructurally normal; they contained increased storage pools of adenine nucleotides and heparin-neutralizing activity and took up serotonin at an increased rate. They aggregated normally with ADP and collagen but failed to aggregate with bovine factor viii and ristocetin. Some change in shape occurred with ADP, and the reduction in adenylate energy change after addition of ADP to platelet-rich plasma was smaller than normal. Platelet coagulant activities including contact product forming activity, intrinsic factor-Xa forming activity and platelet factor 3 activity were normal or increased, but collagen-induced coagulant activity was absent whether tested in washed platelet suspensions or platelet-rich plasma. Platelet washing experiments showed decreased binding of factors V and VIII to hereditary giant platelets and no detectable factor xi in washed platelet suspensions. It is concluded that (1) the hereditary giant platelets studied lacked a binding mechanism for factors, V, VIII and XI; (2) the normal development of collagen-induced coagulant activity apparently depends upon the binding of factor xi to the platelet membrane; and (3) the defective prothrombin consumption observed in these patients may have resulted from the failure of their platelets to bind factor xi.- - - - - - - - - - ranking = 3.5keywords = giant (Clic here for more details about this article) |
6/22. The bernard-soulier syndrome: hereditary giant platelet disease.A patient with the Bernard-Soulier or hereditary giant platelet syndrome, in whom the characteristic morphological features were present and the in vitro abnormalities of platelet aggregation were demonstrated, is reported. Although rare, this syndrome is important, since surgical procedures may be carried out under cover of infused allogeneic platelets.- - - - - - - - - - ranking = 2.5keywords = giant (Clic here for more details about this article) |
7/22. Giant platelets in a case of deletion 11q24-qter confirmed by fluorescence in situ hybridization.Here we report the association of giant platelets and an increase in platelet volume in a 19-month-old black female with de novo del 11q24-qter. The deletion, which was visible on karyotype, was further confirmed and more precisely localized by fluorescence in situ hybridization studies (FISH) that showed the deletion to lie distal to the MLL gene region (11q23). Clinically, the case presented less severe symptoms than Jacobsen syndrome-the well known partial deletion of the distal end of chromosome 11. Platelet glycoproteins CD 41, CD 42a, C 42b, CD 61, and PAC-1 were also assayed and found to be normally expressed. To our knowledge, giant platelets are described for the first time in the relevant deleted region.- - - - - - - - - - ranking = 1keywords = giant (Clic here for more details about this article) |
8/22. Sebastian syndrome: report of the first case in a South American family.The Sebastian syndrome (SS) is a MYH9-related disorders, which are an extremely infrequent group of four autosomal dominant illnesses. SS consist of giant platelets, leukocyte inclusions and thrombocytopenia. To our knowledge, there are no case reports of this syndrome in south america. The propositus was a 35-year-old Argentine woman with a history of purpuric lesions in her lower limbs and thrombocytopenia. Idiopathic thrombocytopenia purpura (ITP) was previously diagnosed, but she did not respond to treatment with steroids. family history failed to provide any evidence of hearing loss, easy bruising, nephritis, renal failure or cataracts. The patient and 11 members of her family were evaluated. The diagnosis of SS was established by demonstrating giant platelets, thrombocytopenia and leukocyte inclusions in peripheral smear in two relatives and by peripheral smear and electronic microscopy in the propositus. MYH9-related disorders should be suspected whenever a patient has a low platelet count or a bleeding diathesis of unknown origin. In these cases, the history, carefully peripheral smear exam, immunocytochemistry and electronic microscopy will be of great help. Differentiation ITP with SS is important to avoid unnecessary diagnostic studies and treatments.- - - - - - - - - - ranking = 1keywords = giant (Clic here for more details about this article) |
9/22. May-Hegglin anomaly: a rare cause of thrombocytopenia.A family with four and an unrelated family with three individuals affected by the May-Hegglin anomaly are described. Platelet counts were markedly reduced and were correctly determined only in the counting chamber. bleeding time and platelet aggregation were always normal, but platelet nucleotide concentrations (ATP and ADP) were elevated. The platelet glycoprotein complexes Ib/IX, IIb/IIIa and Ia/IIa were quantitatively normal. Platelet-associated IgG was slightly elevated, although thrombocytopenia was presumably not caused by an immunological mechanism. Morphological investigations showed giant platelets and spindle-shaped inclusion bodies in the granulocytes, while their function (phagocytic capacity, radical production) was normal. To exclude hereditary types of thrombocytopenia, morphological and family investigations are required to avoid misdiagnosis with far-reaching diagnostic and therapeutic consequences.- - - - - - - - - - ranking = 0.5keywords = giant (Clic here for more details about this article) |
10/22. Hereditary nephritis, platelet disorders and deafness-Epstein's syndrome.A 14-year-old boy with persistent proteinuria (1.6-4.0 g/day), microscopic haematuria, moderate hypertension, macrothrombocytopenia (giant platelets, platelet number 30 x 10(9)/l) and a familial sensorineural hearing loss (the father and the brother were also affected) was studied. kidney biopsy revealed a diffuse mesangial proliferation, and a focal thickening of the glomerular basement membrane was seen on electron microscopy. A normal number of megakaryocytes was observed in bone marrow aspirates. The aggregation response of the platelets to collagen, epinephrine and adenosine diphosphate (ADP) was decreased. The platelet number was slightly diminished, platelets were of normal size in both parents and the brother, and showed a decreased aggregability in response to collagen, epinephrine and ADP in the brother and mother. No functional abnormality of the platelets was observed in the father. urinalysis and kidney function were normal in the family members. This boy with nephritis, platelet disorders and hearing loss corresponds to Epstein's syndrome.- - - - - - - - - - ranking = 0.5keywords = giant (Clic here for more details about this article) |
| | Next -> |