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To become competent killer cells, CD8(+) T cells require stimulation through signal transduction pathways associated with the T-cell receptor, costimulatory molecules such as CD28, and cytokine receptors such as the interleukin (IL)-2 receptor. We used wortmannin and LY294002, two inhibitors of phosphatidylinositol 3-kinase (PI3-K), to study the role of PI3-K in mouse cytotoxic T-lymphocyte (CTL) induction in response to mitogenic anti-CD3 antibody. Anti-CD3-induced CD8(+) T-cell proliferation and CTL development were inhibited dose dependently by both PI3-K inhibitors. IL-2 synthesis by anti-CD3-activated CD8(+) T cells was also diminished by PI3-K inhibition. PI3-K inhibition resulted in a modest decrease in anti-CD3-induced CD4(+) T-cell proliferation but failed to affect IL-2 expression by anti-CD3-activated CD4(+) T cells. PI3-K inhibition during CTL induction resulted in decreased levels of mRNAs coding for granzyme B, perforin, and Fas ligand. In addition, CTL induced in the presence of PI3-K inhibitors failed to conjugate normally with P815 target cells. Exogenous IL-2 did not reverse the effects of PI3-K inhibition on CD8(+) T-cell proliferation and CTL induction. These results support the conclusion that PI3-K activation is involved in T-cell receptor, CD28, and IL-2 receptor signaling of CD8(+) T cells. PI3-K is, therefore, an important component of multiple signal transduction pathways involved in CTL generation. 相似文献
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Denis F. Noubouossie Phu Quoc Lê Francis Corazza France Debaugnies Laurence Rozen Alina Ferster Anne Demulder 《American journal of hematology》2012,87(2):145-149
Changes in several components of the clotting system are well documented in sickle cell disease (SCD) patients. However, whether the global hemostatic potential of these patients is altered is still unclear. Calibrated automated thrombogram® method of thrombin generation (TG) was used to characterize the hemostatic potential of 83 SCD children (75 SS, 6 SC, and 2 Sβ thal) at steady‐state as compared with 50 controls of the same range of age. TG was triggered using 1 pM tissue factor and 4 μM phospholipids with and without thrombomodulin. Thirteen SCD children were also evaluated during vaso‐occlusive crisis. Protein C activity, free protein S and D‐dimers levels were measured in parallel. SCD patients showed higher rates of thrombin formation, higher thrombin peak height (with and without thrombomodulin), and higher endogenous thrombin potential (ETP) than controls in the presence of thrombomodulin. Reduction of ETP (RETP) in the presence of thrombomodulin was lower in SCD group compared with controls and correlated both with protein C and protein S levels. ETP, RETP, peak height, and velocity index of TG correlated with D‐dimers. Compound heterozygous patients showed an intermediate hemostatic phenotype at steady‐state. No significant difference was observed when comparing TG parameters during vaso‐occlusive crisis to those obtained at steady‐state in the same patients. The global hemostatic potential is increased and reflects the hypercoagulable state of SCD patients even at steady‐state. The relevance of this finding with respect to the risk of thrombotic complications of the disease needs further investigation. Am. J. Hematol. 2011. © 2011 Wiley‐Liss, Inc. 相似文献
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Patrick P. Coll MD AGSF Steven Phu MSc Samah H. Hajjar MBBS Ben Kirk PhD Gustavo Duque MD PhD Pam Taxel MD 《Journal of the American Geriatrics Society》2021,69(5):1388-1398
Osteoporosis and sarcopenia are common in older adults. Osteoporosis is a systemic skeletal disease characterized by low bone mass and microarchitectural deterioration of bone tissue, with a consequent increase in bone fragility and susceptibility to fracture. Bone fractures can result in changes in posture, pain, the need for surgical repair and functional impairment. Sarcopenia is the progressive and generalized loss of skeletal muscle mass, strength and/or physical performance. Older adults with sarcopenia experience increased risk of frailty, disability, hospitalizations, mortality, and a reduced quality of life. In this narrative review we provide guidance regarding the prevention of both osteoporosis and sarcopenia, including interventions that prevent both conditions from occurring, recommended screening and treatment to prevent progression. 相似文献
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Activated protein C decreases plasminogen activator-inhibitor activity in endothelial cell-conditioned medium 总被引:12,自引:0,他引:12
van Hinsbergh VW; Bertina RM; van Wijngaarden A; van Tilburg NH; Emeis JJ; Haverkate F 《Blood》1985,65(2):444-451
Confluent cultures of endothelial cells from human umbilical cord were used to study the effect of activated human protein C (APC) on the production of plasminogen activators, plasminogen activator-inhibitor, and factor VIII-related antigen. Addition of APC to the cells in a serum-free medium did not affect the production of tissue-type plasminogen activator (t-PA) or factor VIII-related antigen; under all measured conditions, no urokinase activity was found. However, less plasminogen activator-inhibitor activity accumulated in the conditioned medium in the presence of APC. This decrease was dose dependent and could be prevented by specific anti-protein C antibodies. No decrease was observed with the zymogen protein C or with diisopropylfluorophosphate-inactivated APC. APC also decreased the t-PA inhibitor activity in endothelial cell-conditioned medium in the absence of cells, which suggests that the effect of APC is at least partly due to a direct effect of APC on the plasminogen activator- inhibitor. High concentrations of thrombin-but not of factor Xa or IXa-- had a similar effect on the t-PA inhibitor activity. The effect of APC on the plasminogen activator-inhibitor provides a new mechanism by which APC may enhance fibrinolysis. The data suggest that activation of the coagulation system may lead to a secondary increase of the fibrinolytic activity by changing the balance between plasminogen activator(s) and its (their) fast-acting inhibitor. 相似文献
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Introduction
Cobalamin deficiency may result in hematologic characteristics similar to thrombotic microangiopathy (TMA). To facilitate diagnosis, we reviewed reported cases of acquired cobalamin deficiency presenting with TMA features (c.def-TMA).Methods
A literature search identified reports of c.def-TMA. Deficiency was defined as B12 levels of <118?pmol/L. Corrected reticulocyte counts and reticulocyte production indexes were calculated. Clinical features were presented as proportion abnormal and results summarized as medians and interquartile ranges (IQR).Results
Patient level data was extracted from 41 identified cases. Median age (years) was 43 (30–55) with 21/41 (51%) being female. Cobalamin deficiency was noted in 35/40 (87.5%) but fold increases in MMA and HC were 30 and 6, respectively. The etiology was pernicious anemia in 28/41 (68%) cases. Anemia was both universal and severe, with hemoglobin levels of 55?g/L (4.7–6.6). Hypersegmented neutrophils were noted in 23/37 (62%), schistocytes in 29/38 (76%) and median LDH levels 3981?U/L (2004–5467). The RPI was <3.0% in all patients. Thrombocytopenia occurred in 33/41 (80.5%) with a median platelet count of 91?×?109/L (42–112). Plasma infusion or exchange was initiated in 14/41 (34%) with associated complications in 2 cases.Conclusion
Reticulocytopenia (RPI of <3.0%) was a universal finding that aids in differentiating c.def-TMA from other causes of hemolysis. C.def-TMA was associated with severe anemia, generally mild-moderate thrombocytopenia, and significant elevations in LDH. 相似文献10.
Tran Dac Phu Vu Ngoc Long Nguyen Tran Hien Phan Trong Lan Wayne Lowe Michelle S. McConnell Michael F. Iademarco Jeffrey M. Partridge James C. Kile Trang Do Patrick J. Nadol Hien Bui Diep Vu Kyle Bond David B. Nelson Lauren Anderson Kenneth V. Hunt Nicole Smith Paul Giannone John Klena Denise Beauvais Kristin Becknell Jordan W. Tappero Scott F. Dowell Peter Rzeszotarski May Chu Carl Kinkade 《MMWR. Morbidity and mortality weekly report》2014,63(4):77-80