bluuebunny/crossref_metadata_2025_split huggingface dataset:
Women with the Prothrombophilic HPA-1b Genotype of Platelet Integrin αIIbβ3 Are at Increased Risk of Intrauterine Growth Restriction.
Authors: Gerhardt Andrea , Howe Nadja , Kruessel Jan S. , Bender Hans G. , Scharf Rudiger E. , Zotz Rainer B. 
Published: October 2019

Abstract
Background: Disturbances in the placental vascular development with endothelial inflammation and thrombotic occlusion of the placental vasculature are associated with fetal intrauterine growth restriction (IGR). As shown in previous studies, the HPA-1b allele of the b subunit of the essential platelet integrin αIIbβ3, also known as glycoprotein IIb–IIIa, can be associated with increased platelet thrombogenicity, leading to arterial vascular occlusion also triggered by inflammatory endothelial alterations. We performed a case-control study to assess HPA-1b as risk determinant for fetal IGR.
Materials and Methods: Fifty two women with fetal IGR (defined by birth weight below the 5th- and 10th percentile for gestational age and sex) were evaluated. Women with other reasons of IGR (history of venous thrombosis, fetal loss, and preeclampsia) were excluded. The fetuses were born alive after the 24th week of gestation. As control subjects, 307 normal women with at least one previous pregnancy and no previous pregnancy complication were included.
Results: There was a significant risk association of the HPA-1b/1b genotype (birth weight below 5% percentile: odds ratio (OR) 6.3 (95% confidence interval (CI) 1.4–21); birth weight below 10% percentile: OR 4.6 (95% CI 1.4–15). OR for the HPA-1b/1b genotype (birth weight below 5% percentile) in subgroups with increased levels of fibrinogen (above median > 284mg/dl) were 17.7 (95% CI 2.9–106) and increased levels of FVIII:C (above median > 147%) were 22.1 (95% CI 3.8–127). No significant difference between the genotype distribution was found in patients with low levels of fibrinogen and/or FVIII:C. Similar results were found for women with IGR with a birth weight below the 10% percentile. There was no significant risk association for factor V Leiden G1691A, prothrombin G20210A mutation, and MTHFR 677TT.
Conclusions: The platelet receptor genotype HPA-1b/1b is significantly associated with IGR. As possible pathological mechanism, an increased HPA-1b-associated thrombogenicity of platelets leading to IGR via interaction with an inflammatory vascular process and/or via increased levels of FVIII:C or plasma fibrinogen have to be considered. Pharmacological control of the observed platelet thrombogenicity in patients at risk may be of clinical relevance. In consequence, it will be of importance to examine whether this critical subgroup of patients can benefit from prevention with specific antiplatelet agents.
Calcein and the Labile Iron Pool.
Authors: Soe-Lin Shan , Buss Joan L. , Tang Evelyn , Ponka Prem 
Published: October 2019

Abstract
The labile iron pool is a putative cytosolic compartment of loosely bound, redox-active, chelator-accessible iron. Iron contained within this pool is thought to influence the activity of iron regulatory proteins (IRPs), which bind to iron response elements (IRE) during low iron conditions; this association blocks the translation of ferritin mRNA, and stabilizes transferrin receptor mRNA. High levels of labile iron have been shown to promote oxidative stress. As this pool has such profound effects upon cellular iron homeostasis, there has been great interest in the development of methods to measure labile iron. Calcein, a fluorescent iron chelator, has been widely used to monitor the labile iron pool. When the non-fluorescent acetoxymethyl ester moiety (calcein-AM), enters cells, it is immediately cleaved by cytosolic esterases to its cell-impermeable, fluorescent calcein form. Iron binding to calcein quenches its fluorescence, which can subsequently be recovered following the loss of its iron to a stronger chelator. The difference in fluorescence between the bound and unbound calcein forms is thought to be proportional to the labile iron pool itself. While this method has been commonly exploited, it is unknown whether calcein may over-estimate the size of the labile pool by stripping iron from sources where it may be loosely bound, or by intercepting iron during its passage from one compartment to another. Although it is believed that calcein exerts very little direct influence on cellular iron homeostasis and acts only as a passive sensor of labile iron, some recent evidence from our lab indicates that this may not be the case. We have observed that incubation with calcein results in the activation of IRP-2 and stabilization of HIF-1α, a potent physiological regulator governing the expression of genes involved in oxygen sensing and iron metabolism. Furthermore, we have found that the size of the labile iron pool as measured by calcein was proportional to the amount of calcein loaded in HeLa and K562 cell lines. These findings suggest that calcein may be able to perturb cellular iron homeostasis, and may not accurately reflect the size of the labile iron pool. While calcein may still be used for comparative purposes under identically controlled conditions, its usefulness as a quantifying agent should be regarded with caution.
Iron Chelation, Cell Cycle-Dependent Kinases and HIV-1 Transcription.
Authors: Ammosova Tatyana , Debebe Zufan , Niu Xiaomei , Richardson Des R. , Jerebtsova Marina , Ray Patricio , Gordeuk Victor R. , Nekhai Sergei 
Published: October 2019

Abstract
Iron chelation leads to reduced cell cycle-dependent kinase 2 (CDK2) activity (reviewed in Biochim Biophys Acta2002;1603:31–46). Elongation of HIV-1 transcription is mediated by the interaction of HIV Tat with host cell cycle-dependent kinase 9 (CDK9)/cyclin T1, which phosphorylates the C-terminal domain of RNA polymerase II, and our recent studies indicate that CDK2 is also required for Tat-dependent transcription. We hypothesized that iron chelation may inhibit HIV transcription via reduced activity of cell cycle-dependent kinases. We utilized 2-hydroxy-1-naphthylaldehyde isonicotinoyl hydrazone (311; previously shown to inhibit CDK2 expression) and 4-[3,5-bis-(hydroxyphenyl) -1,2,4-triazol-1-yl]-benzoic acid (ICL670) to chelate intracellular iron. We analyzed the effect of these chelators on HIV-1 transcription using HeLa MAGI and CEM-GFP T-cells containing an integrated HIV-1 promoter and infected with adenovirus expressing HIV-1 Tat protein. Both chelators inhibited Tat-induced HIV-1 transcription, most profoundly in CEM-GFP T-cells. The chelators also inhibited one round of HIV-1 replication in CEM-T cells infected with pseudotyped HIV-1 virus. Treatment of HeLa MAGI and CEM-GFP T-cells with iron chelators decreased CDK9 protein levels and, to a lesser extent, CDK2 protein levels. Our findings provide evidence that iron chelators may inhibit HIV-1 transcription by altering expression of CDK9 and CDK2.
Myoglobin Is a Nitrite Reductase That Generates NO and Regulates Mitochondrial Respiration.
Authors: Shiva Sruti , Huang Zhi , MacArthur Peter H. , Ringwood Lorna A. , Gladwin Mark T. 
Published: October 2019

Abstract
Previous studies have demonstrated that nitrite is an endocrine store of NO that may play an important role in hypoxic vasodilation. Nitrite can be converted to NO enzymatically by deoxyhemoglobin, in a reaction that is under allosteric control with a maximum reaction rate near the hemoglobin P50. In this study, we characterize the nitrite reductase activity of deoxymyoglobin, which reduces nitrite approximately 50-times faster than deoxyhemoglobin due to its lower redox potential. Spectrophotometric measurements show the deoxymyoglobin-nitrite reaction to be second order and linearly dependent on deoxymyoglobin, nitrite and proton concentration with a bimolecular rate constant of 11.7 M−1s−1 at pH 7.4 at 37 degrees Celsius. Using this bimolecular rate constant, we calculate that at physiological concentrations of nitrite (20uM) and myoglobin (25uM), NO will be generated at a rate of 2.85 nM/sec. Since the IC50 of inhibition of mitochondrial respiration is approximately 100nM at physiological oxygen tensions (5–10 μM), we hypothesized that the myoglobin-dependent reduction of nitrite could regulate mitochondrial respiration. Indeed, the addition of deoxymyoglobin in conjunction with nitrite to isolated rat liver mitochondria resulted in the inhibition of respiration, while myoglobin or nitrite alone had no effect. The addition of nitrite to rat heart homogenate, which contains both myoglobin and mitochondria, resulted in a measurable production of NO (with 1mM nitrite addition) and the inhibition of mitochondrial respiration (with 25μM nitrite addition) that was not significantly changed by the addition of the xanthine oxidase inhibitor allopurinol. These data corroborate previous studies demonstrating that NO generated from nitrite reduction can escape heme autocapture to mediate biological responses and confirm that the regulation of mitochondrial respiration by the nitrite-myoglobin reaction is relevant even in a physiological milieu. These data have implications for the modulation of hypoxic respiration, nitrite-dependent hypoxic signaling in tissue, and the regulation of oxygen gradients in the microcirculation.
Ascorbic Acid Catalyzes Nitric Oxide Production from Nitrite Ions.
Authors: Sibmooh Nathawut , Piknova Barbora , Schechter Alan N. 
Published: October 2019

Abstract
We have previously shown that nitrite ions can be reduced by hemoglobin to nitric oxide (NO), a ubiquitous signaling molecule and potent vasodilator. Nitrite serves as a stable tissue and vascular source for NO production; the reduction reaction is maximal at about 50% oxygen saturation values and is enhanced at low pH but little is known about other effectors of this reaction. In the current work, we studied the effect of ascorbic acid on nitrite reduction under physiological conditions using chemiluminescence to quantify NO production. In physiological buffer, this reaction has a rate constant of about 1×10−5 M−1.s−1. Thus, a significant production of NO would likely occur in plasma only at pharmacological levels of ascorbic acid (> 1 mM) although lowering pH below 7.0 markedly enhances this reaction. Loading human erythrocytes with 0.5 mM dehydroascorbic acid, which is in redox equilibrium with ascorbic acid and which can significantly raise intracellular ascorbic acid levels, increased basal levels of nitrite ions from 42±9.0 nM to 98±56 nM. Uptake of nitrite ions into erythrocytes by incubation in 10 μM nitrite was increased about 1.5 fold by dehydroascorbic acid and the half-time of nitrite loss was slowed to the same extent. Ascorbic acid also reduced free ferric heme in erythrocytes and plasma to ferrous heme which catalyzed the reduction of nitrite to NO with a rate constant of 2.3×103 M−1.s−1 under physiological conditions. However, free ferrous ions did not significantly produce NO in physiological buffer (rate constant = 1.8×10−2 M−1.s−1). The reaction of ferrous heme with nitrite was not affected by heme binding to proteins such as hemopexin and albumin, or erythrocyte membranes. These results suggest that physiological levels of ascorbic acid (20–80 μM in plasma and erythrocytes) may act to catalyze NO production in the blood by promoting the reduction of nitrite ions by free ferrous heme and by increasing intra-erythrocytic levels of nitrite ions which can be reduced to NO by deoxyhemoglobin.
Induction of Human γ Globin Gene Expression by Histone Deacetylase Inhibitors.
Authors: Cao Hua 
Published: October 2019

In previous studies we have showed that HDAC inhibitors including hydroxamic acid derivatives of short chain fatty acids butyryl hydroxamate, propionyl hydroxamate, subericbis hydroxamic acid (SBHA), and suberoylanilide hydroxamic acid (SAHA), are potent inducers of γ globin gene expression in in vitro luciferase assays and in cultures of human adult erythroid progenitor cells. In this present study, we used μLCR Aγ transgenic mice to test whether these compounds can also induce γ gene expression in vivo. We found that in addition to γ gene induction these compounds have considerable erythropoiesis activity. Thus, Propionyl and butyryl hydroxamate increased reticulocytes of mice by 71% and 139%, the in vivo BFUe counts by 75% and 51% and the in vivo γ gene expression by 33.9% and 71% respectively. SBHA and SAHA had no erythropoietic activity in vivo. We conclude that Hydroxamic acid derivatives can stimulate both the in vivo erythropoiesis and fetal globin production in a thalassemic murine model.
Cyclic depsipeptide FK228 is a highly potent histone deacetylase inhibitor, currently in clinical trials in cancer patients. We investigated whether FK228 also functions as inducer of human γ globin gene expression and compared Hb F induction by FK228 to that of four other HDAC inhibitors, including hydroxamic acids (TSA), synthetic benzamides (MS-275), and two cyclic tetrapeptides, Apicidin and HC-Toxin. Our results showed that FK228 is the most potent fetal hemoglobin inducer among all the HDAC inhibitors tested in our laboratory. In a concentration of 0.84 nanomolar, FK228 induces γ gene promoter activity in the dual luciferase assay by 7.81 fold. In the human erythroid progenitor cell cultures it increases the levels of γ mRNA by 8.48 fold in a concentration of 0.143 nM. In contrast, fetal hemoglobin induction by other HDAC inhibitors is achieved in concentrations that are 100 to 1000 fold higher. We conclude that FK228 is a promising compound for induction of Hb F in patients with sickle cell disease and thalassemia.
Evolution of Transfusion Requirement in Algerian Thalassemic Major (TM) and Intermediate (TI) Patients Treated with Hydroxyurea (HU).
Authors: Bradai Mohamed , Pissard Serge , Abad Mohand Tayeb , Dechartres Agnes , Ribeil Jean-Antoine , Landais Paul , De Montalembert Mariane 
Published: October 2019

Abstract
Context: Benefits of HU treatment in thalassemic patients are controversial. Most studies agree that HU decreases transfusion requirements in patients with TI, whereas results in patients with TM are inconsistent.
Objectives: To assess the proportion of good responders to HU and the factors associated with good response.
Methods: We initiated HU treatment in 54 thalassemic patients (9 TI and 45 TM). Median ages at first transfusion were 57 months (32–252) in TI and 13 months (4–60) in TM patients. Median ages at inclusion were 12.4 years (4.4–54.9) in TI and 9.9 years (2.0–21.0) in TM patients. Median numbers of erythrocyte concentrates (EC) transfused the year before HU were 3 (1–9) in TI and 12 (8–16) in TM patients (10–65). Good response was defined as more than 70% decrease of transfusional needs one year after beginning HU, partial response as a decrease between 40 and 70%, and non response as a decrease of less than 40%. Patients were transfused when their hemoglobin (Hb) level was < 6g/dL; not transfused when Hb was > 7 g/dL; decision to transfuse was based on clinical status for Hb level between 6 and 7 g/dL. Mean HU dose was 17 ± 2 mg/kg/d (13–21). Mean follow-up was 29.3 ± 14 months.
Results: Eight (90%) TI and 20 (44.5%) TM patients had a good response to HU. No TI and 9 (20%) TM patients had a partial response to HU. One (10%) TI and 16 (35,5%) TM patients had no response to HU. Clinical and hematological tolerance were good except for one 55 yr old TI patient who developed in the 3rd year of treatment an acute myeloblastic leukemia. Retrospectively, a malignant transformation of a pre-existent myeloproliferative disorder can not be excluded and the responsibility of HU is questionable. A better response to HU was associated with a later beginning of transfusion (p=0.02), a higher pre-HU Hb (p= 0.0004), codon 6(-A) mutation (p= 0.002), and with TI diagnosis (p=0.03). On the contrary, Gγ-158 C/C genotype (Xmn1−/−) (p= 0.0001) was associated with a worse response. After adjustment, decrease of transfusional needs was associated with the number of CE transfused the year before HU treatment (p= 0.001), Xmn1 polymorphism (p= 0.003) and the age at the beginning of HU (p=0.03) but not with the type of thalassemia. In conclusion, HU may represent an alternative to transfusions for both TI and TM patients in countries with limited blood supplies when beginning early.
Splenic Synthesis of Factor VIII: Basis for Transplant Therapy of Hemophilia A.
Authors: Suh Matthew Y. , Dada Shirine , Azpurua Humberto , Flynn Evelyn , Briscoe David M. , Kim Heung B. 
Published: October 2019

Abstract
Synthesis of factor VIII by liver sinusoidal endothelial cells has been documented, and liver transplantation for end stage liver disease has been shown to cure concomitant hemophilia A. Given the irreversible nature of liver transplantation, the spleen is an alternate organ of interest in transplant therapy to cure hemophilia A. Factor VIII gene expression in the spleen has been documented by RT-PCR (Hollestelle, M. J. et al, 2001, Thromb Haemost86:855–61), and a recent report of living related splenic transplantation for hemophilia A has shown symptom-free survival up to 4 years (Jiang, H. C. et al, 2006, Transplant Proc38:1483). However, it is unclear which cell populations in the spleen synthesize factor VIII. Immunohistochemistry of murine spleen showed factor VIII staining of the sinusoidal endothelial cells as expected. Surprisingly, clusters of large mononuclear cells in the red pulp also intensely stained for factor VIII. CD31 staining revealed same pattern of sinusoidal endothelial cells and large mononuclear cells in the red pulp. Single cell suspensions of murine spleen analyzed by flow cytometry corroborated significant factor VIII expression (47–70% of all splenic cells). At least 60% of splenic cells were CD31+ CD45+, and these CD31+ CD45+ cells showed significant factor VIII expression (38–48%). When CD31+ cells were depleted by magnetic cell sorting, there was still a subgroup of cells expressing factor VIII (approximately 50%). In summary, we have shown that a significant proportion of splenic cells synthesize factor VIII by flow cytometry and immunohistochemistry. In addition to the sinusoidal endothelial cells, CD31+ CD45+ cells (possibly the large mononuclear cells seen on immunohistochemistry) contribute to splenic synthesis of factor VIII. Based on CD31 depletion study, there is still an unidentified group of cells (CD31-) that contributes to factor VIII synthesis. Further characterization of these cells and an in vivo study in a murine hemophilia A model have been initiated. We conclude that the spleen is a viable source of factor VIII and may be useful in cell-based and/or organ transplant therapy of hemophilia A.
Neutrophils from Cystic Fibrosis Patients Are Defective in Killing of Phagocytosed Pseudomonas aeruginosa.
Authors: Wang Guoshun , Valentine Vincent G. , Lanson Nicholas A. , Leidal Kevin , Zhang Qiang , Lombard Gisele , Thompson Connie , Viswanathan Anand , Nauseef William M. , Wang Guangdi , Painter Richard G. 
Published: October 2019

Abstract
Cystic fibrosis (CF), the most common genetic disease in Caucasians, is caused by mutations of the gene encoding the CF transmembrane conductance regulator (CFTR), a cAMP-regulated chloride channel. CF has long been recognized as an epithelial disease whose most severe complications often occur in the lung. The clinical manifestations include persistent bacterial infection, prominent neutrophil infiltration and small airway obstruction. Even though dramatic advances have been made towards understanding of CF pathogenesis, the link between the CFTR chloride channel defect and a clinical defect in bacterial eradication has not been fully established. Our published data demonstrated that CFTR is expressed in human neutrophils and their phagolysosomes. CF neutrophils are defective in the chlorination of phagocytosed Pseudomonas aeruginosa (PAO1), indicating defective intraphagolysosomal hypochlorous acid (HOCl) production. In the current report, we assessed the bacterial killing abilities of neutrophils from CF and normal individuals. Percoll-purified peripheral blood neutrophils were incubated with opsonized PAO1 at a ratio of 1:1 or 1:50. To define the role of chloride in the killing process, two different Ringer’s buffers with either 0 mM chloride or 135 mM chloride were exploited. At various time points (0, 15, 30 and 60 minutes) after incubation of neutrophils with bacteria, samples were aliquoted to assay for viable bacteria. After correction for bacterial growth over the experimental period, the bacterial viability at each time point relative to that of the initial value was obtained. Two-way ANOVA tests indicated that CF neutrophils had a significantly lower initial rate of killing of PAO1 than that in normal controls. This defect is more pronounced under the condition of high bacterial load and low extracellular chloride. Surprisingly, the low extracellular chloride significantly affected neutrophil-mediated bacterial killing even for the normal neutrophils, suggesting the dependence of this ion in the killing process. Our data provide evidence to suggest the potential role of CFTR in supplying intraphagolysosomal chloride to produce hypochlorous acid (HOCl), an oxidant essential for the killing of HOCl-sensitive bacteria.
A Phase II Study of Nilotinib, a Novel Tyrosine Kinase Inhibitor Administered to Imatinib-Resistant and -Intolerant Patients with Chronic Myelogenous Leukemia (CML) in Chronic Phase (CP).
Authors: le Coutre Philipp , Bhalla Kapil , Giles Francis , Baccarani Michele , Ossenkoppele Gert J. , Hochhaus Andreas , Gattermann Norbert , Rafferty Teresa , Haque Ariful , Weitzman Aaron , Kantarjian Hagop 
Published: October 2019

Abstract
Nilotinib is a potent, highly selective, aminopyrimidine inhibitor which in vitro is 30-fold more potent than imatinib and active against 32/33 imatinib resistant Bcr-Abl mutations. This open-label study was designed to evaluate the safety and efficacy, as defined by hematologic/cytogenetic response rates (HR/CyR) of nilotinib administered at a daily dose of 400 mg bid to imatinib resistant or intolerant CML-CP patients. Daily doses of nilotinib could be escalated to 600 mg BID for patients who did not adequately respond to treatment, and in the absence of safety concerns. Data are available for 132 patients including 91 (69%) with imatinib resistance and 41 (31%) imatinib intolerant. Of the 132 patients, 45 (34%) had a CHR at baseline and 87 (66%) did not. Overall 77 (58%) patients had additional chromosomal abnormalities at baseline, and 16 (12%) had extramedullary involvement. Median age was 58 (range 26–85) years and the median time from first diagnosis to treatment was 57 (range 5–275) months. There were 72 males and 60 females. Nearly half (49%) of the patients had CML for ≥ 5 years and the median overall duration of prior imatinib was 978 days (range 9 to 3468). Treatment with nilotinib is ongoing for 82 of the 132 (62%) patients. A total of 50 (38%) patients have discontinued treatment (26 for adverse events, 15 for disease progression, 7 for other/administrative reasons, and there were two patient deaths (one myocardial infarction in a patient with previous infarctions noted on autopsy, and one with progressive disease). The median duration of nilotinib exposure was 226 (range 3–379) days. The median average dose intensity (mg/days) for all patients, with and without dose escalations, was 800 (range 134 to 1106). CHR was reported in 60 of 87 (69%) patients without a baseline CHR. The median time to CHR was 1.4 months (range 0.3 to 13). Major CyR was observed in 55 (42%), of which 33 (25%) were complete, 22 (17%) partial, 10 (8%) minor, 15 (11%) minimal, 21 (16%) had no cytogenetic response and 4 (3%) had disease progression. The median time to MCyR was 2.6 months (range 0.9 to 8.4). Overall the most frequent Grade 3 or 4 adverse events included thrombocytopenia 34 (26%), neutropenia in 24 (18%), elevated serum lipase in 10 (8%) and anemia in 9 (7%). In summary, nilotinib has demonstrated significant clinical activity as defined by 69% CHR and 42% MCR rates, and an acceptable safety and tolerability profile in patients with imatinib resistant or intolerant CML-CP. Updated information will be presented at the meeting.