193 research outputs found

    Transferrin receptor expression and the regulation of placental iron uptake

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    Placental transferrin receptors, located at the apical side of syncytiotrophoblast, mediate placental iron uptake. Regulation of transferrin receptors on the fetal-maternal exchange area could be a major determinant in the regulation of trans-placental iron transport. Transferrin receptor expression in cultured human term cytotrophoblasts is on a much lower level than in choriocarcinoma cells, with a higher proportion of receptors located on the cell surface. Differentiation of cells, either due to longer culture periods or to 8-bromo-cAMP treatment does not lead to an increase of transferrin receptor expression. In vitro, the level of expression is largely regulated by the cellular density in the culture dishes. Low cellular occupancy of the dish leads to a high level of transferrin receptors. Treatment with iron-sources results in a down regulation of transferrin receptors. Thus, though the level of transferrin receptors in cultured normal trophoblast is at a constant level, unaffected by differentiation, high levels of maternal transferrin-iron availability can lead to a decrease in placental iron uptake. This feed-back mechanism makes placental iron uptake independent of maternal iron stores

    The children anticoagulation and pharmacogenetics study (CAPS): Developing a dosing algorithm for acencocoumarol in paediatric patients

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    Background: Dosing of vitamin K antagonists (VKA) in paediatric patients is complex. The large variability in VKA dose requirement asks for elucidating the factors associated with this variability and taking these into account when defining the dose for a patient. For warfarin, paediatric dosing algorithms have been developed, but not for acenocoumarol. Objectives: To develop a dosing algorithm for acenocoumarol in pediatric patients with and without genetic information. Methods: This multicentre retrospective follow-up study was carried out in Dutch anticoagulation clinics and children's hospitals. Patients were selected when they used acenocoumarol for >1 month between January 1995 and December 2014 and were ≤18 years of age. The primary outcome was the mean daily dose during a stable period. A stable period was defined as ≥3 consecutive international normalized ratio measurements within therapeutic range over a period of ≥3 weeks. Clinical information (including height, weight and indication) and saliva samples for genotyping of CYP2C9 (∗2 and ∗3), VKORC1, CYP4F2, CYP2C18 and CYP3A4 (∗1B and ∗22) were collected. Linear regression was used to analyse their association with the log mean stable dose. Results: In total, 175 patients were included of whom 86 patients had a stable period and no missing clinical information (clinical algorithm cohort) and of 80 also genetic information was available (genetic algorithm cohort). The mean age at the stable period was 9 years. The most common indications were Fontan circulation, prosthetic heart valve, deep venous thrombosis and dilated cardiomyopathy. The clinical algorithm, containing body surface area and indication, explained 45.0% of the variability in dose requirement of acenocoumarol. By adding the genotypes of VKORC1, CYP2C18, and CYP2C9∗2/∗3, 61.8% of the variability was explained (genetic algorithm). Conclusions: Clinical factors had the largest impact on the required dose of acenocoumarol in pediatric patients. Including genetic factors in the algorithm, and especially VKORC1, increased this with 16.8%

    Incidence of bleeding and thrombotic events in non-institutionalized paediatric patients using warfarin in the united kingdom

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    Background: Dosing of vitamin K antagonists (VKA) is complex with large inter- and intra-individual variability in patients' required VKA dose. Over- and underdosing can result in bleeding and thrombotic events. The incidence of these events in paediatric patients on warfarin therapy in a European population is unknown. Objectives: To estimate the incidence of bleeding and thrombotic events in warfarin using paediatric patients in the UK and to characterise patients who do or do not experience a bleeding or thrombotic event. Methods: Data were obtained from the UK CPRD in the period between January 1998 and November 2016. Using a cohort design, we identified all patients with ≥1 prescription for warfarin and who were ≤18 years. The date of the first prescription marked the start of the follow-up. Follow-up was classified into periods of warfarin use and non-use. Patients were followed until 19 years of age, death or departure from the practice. The incidence of non-fatal bleeding and thrombotic events was assessed using both information from CPRD and the linked Hospital Episode Statistics (HES). Fatal events were identified usings the linked mortality data from the Office for National Statistics (ONS). For calculating the incidence of thrombotic events only patients without a history of thrombosis were included. Results: In total, 685 patients were identified (median age 15 years, 45.4% female) of whom 372 could be linked to the HES and ONS databases. The incidence of bleeding and thrombotic events during warfarin use was 4.08 and 1.27/100 patient years, respectively. The incidence of bleeding events during non-use was 2.65/100 patient years (relative risk 1.58, 95% confidence interval [0.89-2.80]). Only 2 fatal events occurred, one bleeding and one thrombotic event. Patients with a bleeding event tended to have a higher percentage of INR measurements with a value above 4 (9.4 vs 3.9%) and a lower fraction below 2 (18.4 vs 39.1%) compared to patients without a bleeding event during the whole follow-up. Patients with a thrombotic event showed the opposite trend, a higher percentage of INRs below 2 (45.8 vs 29.5%) and a lower percentage of INRs above 4 (2.7 vs 5.3%). All differences were not statistically significant which maybe due to the small sample size. Conclusions: The incidence of bleeding events was higher than of thrombotic events. The trends in percentages of INRs under and above therapeutic range suggest that keeping the INR within range could decrease the occurence of these events

    Characteristics and quality of oral anticoagulation treatment in pediatric patients in the Netherlands based on the CAPS cohort

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    Essentials: The knowledge of quality and safety of acenocoumarol and phenprocoumon use in children is limited. We used data from a multicenter retrospective follow-up study in children in the Netherlands. The quality of anticoagulation control in the first month of use was low, but improved thereafter. No thromboembolic events occurred, however bleeding events occurred in 1-3 out of 10 patients. Summary: Background: The use of vitamin-K antagonists in pediatric patients is rare and information on the quality and safety of treatment with acenocoumarol and phenprocoumon is limited. Objectives: To assess the quality, safety and effectiveness during the first year of acenocoumarol and phenprocoumon treatment in pediatric patients in the Netherlands. Methods: The Children Anticoagulation and Pharmacogenetics Study (C

    Allogeneic Stem Cell Transplantation From HLA-Mismatched Donors for Pediatric Patients with Acute Lymphoblastic Leukemia Treated According to the 2003 BFM and 2007 International-BFM Studies: Impact of Disease Risk on Outcomes.

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    Summary Rational Allogeneic HSCT is beneficial for pediatric patients with relapsed or (very) high-risk ALL in remission. A total of 1115 consecutive patients were included in the ALL SCT 2003 BFM study and the ALL SCT 2007-International study and were stratified according to relapse risk (Standard vs. High vs. Very High Risk of Relapse) and donor type (Matched Sibling vs. Matched Donor vs. Mismatched Donor). Patients and methods A total of 148 patients (60% male, median age 8.7 years; B-cell precursor ALL: 75%) were transplanted from MMD, which was defined as either less than 9/10 HLA-compatible donors or less than 5/6 unrelated cord blood after myelo-ablative conditioning regimen (TBI-based: 67%) for HRR (n=42) or VHRR disease (n=106). The stem cell source was either BM (n=31), unmanipulated PBSCs (n=28), T-cell ex vivo depleted PBSCs (n=59) or cord blood (n=25). The median follow-up was 5.1 years. Results The 4-year OS and EFS was 56±4% and 52±4%, respectively, for the entire cohort. Patients transplanted from MMD for HRR disease obtained remarkable 4-y OS and EFS values of 82±6% and 80±6%, respectively, while VHRR patients obtained values of 45±5% and 42±5% (p Conclusion HSCT with a mismatched donor is feasible in pediatric ALL patients but leads to inferior results compared to HSCT with better matched donors, at least for patients transplanted for VHRR. The results are strongly affected by disease status. The main cause of treatment failure is still relapse, highlighting the urgent need for interventional strategies after HSCT for patients with residual leukemia before and/or after transplantatio

    Модель взаємовідносин між державою та фінансово-промисловими групами для різних бізнес-систем

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    Мета дослідження - визначення пріоритетів та стратегічних напрямків формування ефективної моделі взаємодії української держави з вітчизняними фінансово-промисловими групами в сучасних умовах економічного розвитку

    The impact of donor type on the outcome of pediatric patients with very high risk acute lymphoblastic leukemia. A study of the ALL SCT 2003 BFM-SG and 2007-BFM-International SG

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    Allogeneic HSCT represents the only potentially curative treatment for very high risk (VHR) ALL. Two consecutive international prospective studies, ALL-SCT-(I)BFM 2003 and 2007 were conducted in 1150 pediatric patients. 569 presented with VHR disease leading to any kind of HSCT. All patients >2 year old were transplanted after TBI-based MAC. The median follow-up was 5 years. 463 patients were transplanted from matched donor (MD) and 106 from mismatched donor (MMD). 214 were in CR1. Stem cell source was unmanipulated BM for 330 patients, unmanipulated PBSC for 135, ex vivo T-cell depleted PBSC for 62 and cord-blood for 26. There were more advanced disease, more ex vivo T-cell depletion, and more chemotherapy based conditioning regimen for patients transplanted from MMD as compared to those transplanted from MSD or MD. Median follow up (reversed Kaplan Meier estimator) was 4.99 years, median follow up of survivals was 4.88, range (0.01–11.72) years. The 4-year CI of extensive cGvHD was 13 ± 2% and 17 ± 4% (p = NS) for the patients transplanted from MD and MMD, respectively. 4-year EFS was statistically better for patients transplanted from MD (60 ± 2% vs. 42 ± 5%, p < 0.001) for the whole cohort. This difference does not exist if considering separately patients treated in the most recent study. There was no difference in 4-year CI of relapse. The 4-year NRM was lower for patients transplanted from MD (9 ± 1% vs. 23 ± 4%, p < 0.001). In multivariate analysis, donor-type appears as a negative risk-factor for OS, EFS, and NRM. This paper demonstrates the impact of donor type on overall results of allogeneic stem cell transplantation for very-high risk pediatric acute lymphoblastic leukemia with worse results when using MMD stem cell source
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