A patient with a lifelong bleeding disorder is presented with a prolonged bleeding time and abnormal aggregation and secretion responses to arachidonic acid, thromboxane A2, PAF-acether and the divalent calcium ionophore A23187. Platelet alpha and dense granule contents and morphology appear normal. The proposed defect is due to an abnormality of a platelet intracellular calcium dependent process.

Toxoplasma gondii is an apicomplexan parasite with a broad host range of most warm-blooded mammals including humans, of which one-thirds of the human population has been infected worldwide which can cause congenital defects, abortion, and neonatal complications. Here, we developed a rapid diagnostic test (RDT) for T. gondii infection. Antigenic N-terminal half of the major surface antigen (SAG1...

BACKGROUND AND OBJECTIVES Toxoplasma gondii is an obligatory intracellular parasite which causes severe diseases in the fetus of pregnant women and immunocopmromised patients. Serological tests based on recombinant protein are one of the main diagnosis methods for the detection of specific antibodies in serum samples. Dense granule antigenic proteins derived from T. gondii (TgGRAs) are potentia...

Peroxynitrite (ONOO-) strongly inhibits agonist-induced platelet responses. However, the mechanisms involved are not completely defined. Using porcine platelets, we tested the hypothesis that ONOO- reduces platelet aggregation and dense granule secretion by inhibiting energy production. It was found that ONOO- (25-300 microM) inhibited collagen-induced dense granule secretion (IC50 = 55 +/- 7 m...

Toxoplasma gondii sporozoites form two parasitophorous vacuoles during development within host cells, the first (PV1) during host cell invasion and the second (PV2) 18 to 24 h postinoculation. PV1 is structurally distinctive due to its large size, yet it lacks a tubulovesicular network (C. A. Speer, M. Tilley, M. Temple, J. A. Blixt, J. P. Dubey, and M. W. White, Mol. Biochem. Parasitol. 75:75-...

Nonreplicating type I uracil auxotrophic mutants of Toxoplasma gondii possess a potent ability to activate therapeutic immunity to established solid tumors by reversing immune suppression in the tumor microenvironment. Here we engineered targeted deletions of parasite secreted effector proteins using a genetically tractable Δku80 vaccine strain to show that the secretion of specific rhoptry (RO...

A member of the RNA-binding protein family, T-cell intracellular antigen-1 (TIA1) regulates mRNA translation and splicing as well cellular stress by promoting granule formation. Variants TIA1 gene have implications in neurogenerative disorders including amyotrophic lateral sclerosis (ALS) frontotemporal dementia (FTD). Reproducible research on TIA1 would be enhan...

Monoclonal antibodies to insulin secretory granule membranes were obtained following immunization of mice with granule membranes purified from a rat transplantable insulinoma. The specificities of the antibodies were investigated by using binding assays with different insulinoma subcellular fractions, by indirect immunofluorescence studies with intact and permeabilized cells, and by immunoblott...

Gunmetal (gm/gm) is a recessively inherited mouse pigment dilution mutant that has high mortality and poor reproductive rates. In these studies, several hematologic defects were found associated with the mutation, including prolonged bleeding times, together with thrombocytopenia and increased platelet size. A unique feature is the presence of simultaneous abnormalities in two platelet organell...

Subcellular membrane and granule fractions derived from human platelets contain factor VIIII antigen and von Willebrand factor activity but not factor VII procoagulant activity. Circulating platelets constitute a significant reservoir of plasma factor VIII antigen, containing approximately 15% of the amount of factor VIII antigen present in platelet-poor plasma. The antibiotic ristocetin, which...