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The Etiology of the Antiphospholipid Syndrome
Published in Howard J.A. Carp, Recurrent Pregnancy Loss, 2020
Sara De Carolis, Giuseppina Monteleone, Cristina Garufi, Rotem Inbar, Miri Blank, Yehuda Shoenfeld
Furthermore, aPL may influence the placental circulation by attacking certain placental epitopes such as Annexin A5, a potent anticoagulant protein. Annexin V, found on the apical surface of placental syncytiotrophoblast, forms a protective shield on the phospholipid surface, blocking phospholipids from becoming available for coagulation reactions. The annexin-V shield could be damaged by either binding to anti-annexin-V or preventing its binding to the PL membrane, or by blocking autoantibodies against annexin-V/PL [36]. Anti-annexin-V autoantibodies have been detected in patients with systemic lupus erythematosus (SLE) and APS associated with pregnancy loss, while reduced levels of annexin-V have been observed on the placental villi of women with aPL, recurrent pregnancy loss, and a thrombogenic background [37].
The Labeling of Peptides with Positron-Emitting Radionuclides: The Importance of PET in Cancer Diagnosis
Published in Marco Chinol, Giovanni Paganelli, Radionuclide Peptide Cancer Therapy, 2016
Stefano Papi, Nicoletta Urbano, Esteban R. Obenaus, Marco Chinol
Apoptosis, or programmed cell death, plays a crucial role in development of cancer. Cells that are deficient in their apoptotic response can potentially become tumorigenic. Annexin V is a 36-kDa protein that binds with high affinity (dissociation constant about 10 nM) to phosphatidylserine (PS), a phospholipid that is normally found only on the interior of the cell membrane but is redistributed to the exterior of the cell membrane in the early stages of apoptosis. The highly regulated apoptosis pathway can thus be imaged in its early phase by specific binding with radiolabeled annexin V.
Imaging Apoptosis
Published in Martin G. Pomper, Juri G. Gelovani, Benjamin Tsui, Kathleen Gabrielson, Richard Wahl, S. Sam Gambhir, Jeff Bulte, Raymond Gibson, William C. Eckelman, Molecular Imaging in Oncology, 2008
The annexin A5 is a 36-kDa serum protein including 320 amino acids that binds specifically to the exposed PS in presence of calcium ions (23–25). This nanomolar affinity between annexin A5 and PS has been shown to be a specific signal for the phagocytosis of apoptotic bodies by macrophages (26).
High fragmentation in platelet concentrates impacts the activation, procoagulant, and aggregatory capacity of platelets
Published in Platelets, 2023
Nahreen Tynngård, Aseel Alshamari, Per Sandgren, Dermot Kenny, Ana Maria Vasilache, Mohammad R. Abedi, Sofia Ramström
To address this, we studied PCs with different initial compositions in regard to platelet fragmentation and its impact on storage-induced changes in activation potential. A novel flow cytometry protocol was used, which simultaneously evaluates five important platelet functions described below. PAC-1 binds to the active conformational form of the fibrinogen receptor GPIIb/IIIa, necessary for platelet aggregation [6]. Annexin V binds to phosphatidylserine (PS), needed for assembly of the prothrombinase complex on platelets. Loss of DiIC1(5) staining indicates decreased mitochondrial membrane potential as occurs in procoagulant platelets [7]. P-selectin and LAMP-1 exposures are signs of α-granule release and lysosomal exocytosis, respectively [8]. Furthermore, the protocol allows for the analysis of platelet subpopulations, e.g., normal-sized platelets, the formation of smaller, procoagulant platelets, and platelet fragments (microparticles), which normally appear following strong stimulation of the platelets [9]. Furthermore, aggregation capacity and release of soluble platelet activation markers were determined.
Does LH supplementation in poor responders affect granulosa cells apoptosis rate in ART? A prospective randomised controlled trial
Published in Journal of Obstetrics and Gynaecology, 2022
Sebnem Alanya Tosun, Enis Ozkaya, Basak Aru, Gulderen Yanikkaya Demirel, Ebru Cogendez, Mehmet Sipahi
Flow cytometry is an actual technique used to detect GCs (about 5000 per follicle) and CD45 monoclonal antibody is useful to remove the white blood cell fraction to improve the accuracy of isolating them. During the apoptosis process, phosphatidylserine (PS) translocates from the inner side of the plasma membrane to the outer side and causes the asymmetric shape of the plasma membrane as an early event. Annexin V is a calcium-dependent phospholipid-binding protein that strongly interacts with PS (van Engeland et al. 1998). Additionally, co-staining with propidium iodide (PI) and analysing by flow cytometry, GCs are assessable as viable cells (annexin V− PI−), early apoptotic cells (annexinV+ PI−), late apoptotic cells (annexin V+ PI+) and necrotic cells (annexinV−PI+) (Fan et al. 2019). There was no significant effect of hyaluronidase treatment on cell viability and apoptosis rates.
The Safe Soluble Compound Dehydroascorbic Acid Inhibits Various Upstream and Downstream Effectors of PI3K and KRAS Signaling Pathways in Undruggable PIK3CA/KRAS-Mutant Colorectal Cancer Stem-Like Cells
Published in Nutrition and Cancer, 2021
Fahimeh Kalbkhani, Ali Pirnejad, Sohrab Sam, Mohammad Reza Sam
Apoptosis was analyzed by a double-staining method using Annexin-V FLOUS/Propidium iodide (PI) labeling solution according to the manufacturer's instructions. In apoptotic cells, the membrane phospholipid phosphatidylserine, which is normally found in the internal portion of the cell membrane, is translocated to the outer leaflet of the plasma membrane, thereby exposing phosphatidylserine to the external environment. Annexin-V is a calcium-dependent phospholipid binding protein that has an affinity for phosphatidyl serine and is useful in identifying apoptotic cells. PI binds to cellular DNA is useful in identifying necrotic cells. LS174T cells were treated with 100-, 500-, and 1000 μM L-DHA for 48 h. Thereafter, the cells were washed twice with sterile cold PBS buffer and after centrifugation, cell pellets were then resuspended in 100 μl of 1× binding buffer at a density of 5 × 105 cells/ml with FITC-Annexin V. The cells were gently mixed and incubated in the dark at room temperature for 20 min. To differentiate cells with membrane damage, PI solution was added to the cell suspension prior to the flow cytometric analysis using a fluorescence-activated cell sorter (Dako, USA). Early apoptosis was defined as cells positive for Annexin V-FITC only. Late apoptosis was defined as cells positive for Annexin V-FITC and PI, and necrotic cells were defined as cells positive for PI only.