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Dive into the research topics where Maciej Niedźwiecki is active.

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Featured researches published by Maciej Niedźwiecki.


Journal of Chromatography A | 2016

Hydrophilic interaction chromatography combined with dispersive liquid–liquid microextraction as a preconcentration tool for the simultaneous determination of the panel of underivatized neurotransmitters in human urine samples

Lucyna Konieczna; Anna Roszkowska; Maciej Niedźwiecki; Tomasz Bączek

A simple and sensitive method using dispersive liquid-liquid microextraction (DLLME) followed by liquid chromatography coupled to mass spectrometry (LC-MS) with a hydrophilic interaction chromatography (HILIC) column was developed for the simultaneous determination of 13 compounds of different polarities, comprising monoamine neurotransmitters (dopamine, norepinephrine, epinephrine and serotonin) along with their respective precursors and metabolites, in human urine samples. The microextraction procedure was based on the fast injection of a mixture of ethanol (disperser solvent) and dichloromethane (extraction solvent) into a human urine sample, forming a cloudy solution in the Eppendorf tube. After centrifugation, the sedimented phase was collected and subsequently analyzed by LC-HILIC-MS in about 12min without a derivatization step. The separation was performed on an XBridge Amide™ BEH column 3.0×100mm, 3.5mm and the mobile phase consisted of phase A: 10mM ammonium formate buffer in water pH 3.0 and phase B: 10 mM ammonium formate buffer in acetonitrile, under gradient program elution. Tyrosine, tryptophan, 5-hydroxytryptophan, dopamine, epinephrine, norepinephrine, serotonin, 3-methoxytyramine, 5-hydroxyindole-3-acetic acid, 3,4-dihydroxy-l-phenylalanine and norvaline (internal standard) were detected in the positive ionization mode. While vanillylmandelic acid, homovanillic acid, 3,4-dihydroxyphenylacetic acid and 3,4-dihydroxybenzylamine (internal standard) were detected in the negative ionization mode. Parameters influencing DLLME and LC-HILIC-MS were investigated. Under the optimum conditions, the proposed method exhibited a low detection limit (5-10ngmL(-1)), and good linearity with R between 0.9991 and 0.9998. The recoveries in human urine samples were 99.0%±3.6%. for the 13 studied biogenic amines with intra- and inter-day RSDs of 0.24-9.55% and 0.31-10.0%, respectively. The developed DLLME-LC-MS method could be successfully applied for the determination of trace amounts of polar endogenous compounds, such as neurotransmitters, in human urine samples, including samples with a reduced volume obtained from pediatric patients.


Pediatric Diabetes | 2009

Difficulties or mistakes in diagnosing type 1 diabetes in children?—demographic factors influencing delayed diagnosis

Małgorzata Pawłowicz; Dorota Birkholz; Maciej Niedźwiecki; Anna Balcerska

Background: Diabetic ketoacidosis (DKA) development in children with new‐onset type 1 diabetes (T1DM) is often the main consequence of delayed diagnosis.


Journal of Pharmaceutical and Biomedical Analysis | 2012

Topotecan exposure estimation in pediatric acute myeloid leukemia supported by LC-MS-based drug monitoring and pharmacokinetic analysis.

Tomasz Bączek; Lucyna Konieczna; Mariusz Belka; Lucyna Maciejka-Kapuścińska; Jakub Wiśniewski; Maciej Niedźwiecki; Anna Balcerska; Elżbieta Adamkiewicz-Drożyńska; Jacek Wachowiak

Individualization of the topotecan dosing can reduce inter-patient variability, toxicity, and at the same time increases chemotherapy efficacy. Topotecan dosing based on simultaneous drug monitoring and pharmacokinetic analysis can yield more accurate and precise estimation of the topotecan systemic exposure than that attainable with the fixed dosing approach. Therefore, a combined approach could provide a tool assisting the clinicians in individualization of the topotecan dosing. The aim of the study was to estimate the topotecan exposure in pediatric patients with acute myeloid leukemia (AML) based on the plasma concentration-time data and using the pharmacokinetic analysis. The primary goal was achieve the correct estimation of the target plasma area against the topotecan concentration-time curve (AUC) in a 5 day course of cladribine followed by monitored topotecan in pediatric patients with recurrent/refractory AML. A sensitive and selective reversed-phase liquid chromatographic-mass spectrometry (LC-MS) assay was developed to quantify total topotecan in the human plasma samples. This method, with its lower quantification limit of 1 ng/ml, was validated over a linear range of 1-150 ng/ml. Under the proposed approach, the topotecan dosing was selected so as to achieve the final AUC value of 140±20 ng/ml h. The presented analytical and pharmacokinetic data demonstrate that the proposed approach can be a practical, useful, efficient, and accurate tool for individualizing the topotecan dosing in children with AML.


Journal of Chromatography A | 2018

Bioanalysis of underivatized amino acids in non-invasive exhaled breath condensate samples using liquid chromatography coupled with tandem mass spectrometry

Lucyna Konieczna; Magdalena Pyszka; Magdalena Okońska; Maciej Niedźwiecki; Tomasz Bączek

Exhaled breath condensate (EBC) is receiving increased attention as a novel, entirely non-invasive technique for collecting biomarker samples. This increased attention is due to the fact that EBC is simple, effort independent, rapid, can be repeated frequently, and can be performed on young children and patients suffering from a variety of diseases. By having a subject breathe tidally through a cooling system for 15-20u202fmin, a sufficient amount of condensate is collected for analysis of biomarkers in clinical studies. However, bioanalysis of EBC involves an unavoidable sample preparation step due to the low concentration of its components. Thus, there is a need for a new and more sensitive analytical method of assessing EBC samples. While researchers have considered analyses of single and small quantities of amino acids - for example, those connected with leukemia - no one has previously attempted to simultaneously analyze a panel of 23 amino acids. Moreover, the present study is well-justified, as prior studies focusing on single amino acids and leukemia at the moment of diagnosis and during chemotherapy (33u202fdays of treatment) are inconsistent. In the present study, amino acids were separated using an XBridge Amide column (3u202fmmu202f×u202f100u202fmm, 3.5u202fμm). The mobile phase consisted of 10u202fmM of ammonium buffer in water with a pH of 3 (Phase A) and 10u202fmM ammonium buffer in acetonitrile (Phase B) under gradient program elution. The analytes were detected in electrospray positive ionization mode. Under optimal conditions, the proposed method exhibited limits of quantification (LOQ) in the range of 0.05-0.5u202fng/mL, and good linearity, with the determination coefficient (R2) falling between 0.9904 and 0.9998. The accuracy in human exhaled breath condensate samples ranged between 93.3-113.3% for the 23 studied amino acids, with intra- and inter-day coefficient of variation (CVs) of 0.13-9.92% and 0.17-10.53%, respectively. To demonstrate the liquid chromatography with hydrophilic interaction with electrospray source coupled to tandem mass spectrometry (LC-HILIC-ESI-MS/MS) methods applicability for biomedical investigations, it was verified and applied to determine amino acids in pediatric patients with leukemia. These tests confirmed that glutamine, arginine, homoarginine, asparagine, histidine, methionine, proline, hydroxyproline, threonine, tyrosine, and valine were present in significantly higher levels in pediatric leukemia patients than in the healthy control group. The developed assay is an attractive alternative to standard analytical methods, because it allows for the non-invasive, fast, sensitive, and reliable analysis of amino acids without derivatization in EBC.


Advances in Clinical and Experimental Medicine | 2018

Imatinib in the treatment of chronic myeloid leukemia in children and adolescents is effective and well tolerated: Report of the Polish Pediatric Study Group for the Treatment of Leukemias and Lymphomas

Małgorzata Janeczko-Czarnecka; Maryna Krawczuk-Rybak; Irena Karpińska-Derda; Maciej Niedźwiecki; Katarzyna Musioł; Magdalena Ćwiklińska; Katarzyna Drabko; Katarzyna Mycko; Tomasz Ociepa; Katarzyna Pawelec; Danuta Januszkiewicz-Lewandowska; Marek Ussowicz; Blanka Rybka; Renata Ryczan-Krawczyk; Andrzej Kołtan; Grażyna Karolczyk; Agnieszka Zaucha-Prażmo; Wanda Badowska; Krzysztof Kałwak

BACKGROUNDnChronic myeloid leukemia (CML) constitutes only 2-3% of all leukemias in pediatric patients. Philapelphia chromosome and BCR-ABL fusion are genetic hallmarks of CML, and their presence is crucial for targeted molecular therapy with tyrosine kinase inhibitors (TKIs), which replaced hematopoietic stem cell transplantation (HSCT) as a standard first-line therapy. The disease in pediatric population is rare, and despite molecular and clinical similarities to CML in adults, different approach is needed, due to the long lifetime expectancy and distinct developmental characteristics of affected children.nnnOBJECTIVESnThe objective of this study is to evaluate treatment with imatinib in Polish pediatric patients with CML.nnnMATERIAL AND METHODSnWe analyzed the results of treatment with imatinib in 57 pediatric patients (June 2006 - January 2016) from 14 Polish pediatric hematology and oncology centers.nnnRESULTSnIn the study group, 40 patients continued imatinib (median follow-up: 23.4 months), while in 17 the treatment was terminated (median follow-up: 15.1 months) due to therapy failure. In the latter group, 13 patients underwent HSCT, while 4 switched to second-generation TKIs. The 5-year overall survival rate (OS) in the study group was 96%, and the 5-year event-free survival (EFS) was 81%.nnnCONCLUSIONSnOur results confirm that the introduction of TKI therapy has revolutionized the treatment of CML in the pediatric population by replacing the previous method of treatment with HSCT and allowing a high percentage of OS and EFS.


Pediatric Hematology and Oncology | 2017

Outcome of acute lymphoblastic leukemia in children with down syndrome—Polish pediatric leukemia and lymphoma study group report

Joanna Zawitkowska; Teresa Odój; Katarzyna Drabko; Agnieszka Zaucha-Prażmo; Julia Rudnicka; Michał Romiszewski; Michał Matysiak; Kinga Kwiecińska; Magdalena Ćwiklińska; Walentyna Balwierz; Joanna Owoc-Lempach; Katarzyna Derwich; Jacek Wachowiak; Maciej Niedźwiecki; Elżbieta Drożyńska; Joanna Trelinska; Wojciech Mlynarski; Andrzej Kołtan; Mariusz Wysocki; Renata Tomaszewska; Tomasz Szczepański; Marcin Płonowski; Maryna Krawczuk-Rybak; Tomasz Ociepa; Tomasz Urasiński; Agnieszka Mizia-Malarz; Grażyna Sobol-Milejska; Grażyna Karolczyk; Jerzy Kowalczyk

ABSTRACT Children with Down syndrome (DS) have a 20-fold increased risk of developing leukemia compared with the general population. The aim of the study was to analyze the outcome of patients diagnosed with Down syndrome and acute lymphoblastic leukemia (ALL) in Poland between the years 2003 and 2010. A total of 1848 children were diagnosed with ALL (810 females and 1038 males). Of those, 41 (2.2%) had DS. The children were classified into three risk groups: a standard-risk group—14 patients, an intermediate-risk group—24, a high-risk group—3. All patients were treated according to ALLIC 2002 protocol. The median observation time of all patients was 6.1 years, and in patients with DS 5.3 years. Five-year overall survival (OS) was the same in all patients (86% vs 86%, long-rank test, p = .9). The relapse-free survival (RFS) was calculated as 73% in patients with DS and 81% in patients without DS during a median observation time (long-rank test, p = .3). No statistically significant differences were found in the incidence of nonrelapse mortality between those two groups of patients (p = .72). The study was based on children with ALL and Down syndrome who were treated with an identical therapy schedule as ALL patients without DS, according to risk group. This fact can increase the value of the presented results.


Medical and Biological Sciences | 2016

Improvement of cure after hematopoietic stem cel transplantations in children

Jan Styczynski; Robert Dębski; Anna Krenska; Krzysztof Czyżewski; Sylwia Kołtan; Ninela Irga-Jaworska; Magdalena Szalewska; Maciej Niedźwiecki; Joanna Stefanowicz; Elżbieta Adamkiewicz-Drożyńska; Marcin Płonowski; Elzbieta Leszczynska; Maryna Krawczuk-Rybak; Tomasz Ociepa; Tomasz Urasiński; Mariusz Wysocki

Wstep. Transplantacja komorek krwiotworczych (HSCT) jest wazną metodą terapeutyczną w wielu wrodzonych i nabytych chorobach, w tym nowotworowych, zespolach niewydolności szpiku oraz zaburzeniach immunologicznych i metabolicznych. Celem pracy jest analiza wynikow HSCT w pojedynczym ośrodku pediatrycznym w okresie 12 lat. Pacjenci i metodyka. Analizie poddano wyniki przeszczepien wykonanych w latach 2003-2015 w Klinice Pediatrii, Hematologii i Onkologii w Bydgoszczy. Transplantacje analizowano w trzech przedzialach czasowych: 2004-2007, 2008-2011 oraz 2012-2015. Wyniki. Wykonano 318 HSCT, w tym 186 alloge-nicznych (68 zgodnych rodzinnych i 118 od dawcow alternatywnych) oraz 132 autologiczne. Średnie przezycie po HSCT, wyznaczone metodą Kaplana-Meiera wynioslo 8,1 lat. Calkowite prawdopodobienstwo przezycia (pOS) wynioslo 0,64±0,03; pOS po allo-HSCT wynosi 0,62±0,04, a po auto-HSCT 0,67±0,05. Nie wykazano znamiennych roznic w pOS zarowno po allo-HSCT, jak i po auto-HSCT pomiedzy drugim (2008-2011) i trzecim (2012-2015) analizowanym okresie. Jednakze, pOS bylo wyzsze w dru-gim i trzecim okresie w stosunku do okresu pierwszego (2004-2007), zarowno dla wszystkich pacjentow, jak i u pacjentow po auto-HSCT. W grupie pacjentow allo-HSCT, uzyskano wzrost pOS o ponad 20% (43% vs 66% vs 64% w kolejnych przedzialach czasu; ns). Wnioski. Wyniki HSCT uzyskiwane aktualnie w na-szym ośrodku są porownywalne z wynikami podawanymi w miedzynarodowych rejestrach.


European Journal of Haematology | 2018

Clinical characteristics and analysis of treatment result in children with Ph-positive acute lymphoblastic leukaemia in Poland between 2005 and 2017

Joanna Zawitkowska; Monika Lejman; Agnieszka Zaucha-Prazmo; Katarzyna Drabko; Marcin Płonowski; Joanna Bulsa; Michał Romiszewski; Agnieszka Mizia-Malarz; Andrzej Kołtan; Katarzyna Derwich; Grażyna Karolczyk; Tomasz Ociepa; Magdalena Ćwiklińska; Joanna Trelinska; Joanna Owoc-Lempach; Maciej Niedźwiecki; Aleksandra Kiermasz; Jerzy Kowalczyk

The aim of this study was to analyse the clinical characteristics and outcome of children diagnosed with Ph+ ALL.


Clinical & Developmental Immunology | 2018

CD4+CD25highCD127low/−FoxP3+ Regulatory T Cell Subpopulations in the Bone Marrow and Peripheral Blood of Children with ALL: Brief Report

Maciej Niedźwiecki; O. Budziło; M. Zieliński; Elżbieta Adamkiewicz-Drożyńska; L. Maciejka-Kembłowska; Tomasz Szczepański; P. Trzonkowski

CD4+CD25highCD127low/−FoxP3+ regulatory T cells (Tregs) are currently under extensive investigation in childhood acute lymphoblastic leukemia (ALL) and in other human cancers. Usually, Treg cells maintain the immune cell homeostasis. This small subset of T cells has been, in fact, considered to be involved in the pathogenesis of autoimmune diseases and progression of acute and chronic leukemias. However, whether Treg dysregulation in CLL and ALL plays a key role or it rather represents a simple epiphenomenon is still a matter of debate. Treg cells have been proposed as a prognostic indicator of the clinical course of the disease and might also be used for targeted immune therapy. Our study revealed statistically higher percentage of Treg cells in the bone marrow than in peripheral blood in the group of 42 children with acute lymphoblastic leukemia. By analyzing Treg subpopulations, it was shown that only memory Tregs in contact with leukemic antigens showed statistically significant differences. We noticed a low negative correlation between Treg cells in the bone marrow and the percentage of blasts (R = −0.36) as well as a moderate correlation between Treg cells in the bone marrow and Hb level (R = +0.41) in peripheral blood before therapy. The number of peripheral blood blasts on day 8th correlates negatively (R = −0.36) with Tregs. Furthermore, statistical analysis revealed low negative correlation between the number of Tregs in the bone marrow and the minimal residual disease measured on day 15th, the percentage of blasts in the bone marrow and leukocytosis after 15 days of chemotherapy. These results indicate the influence of Tregs on the final therapeutic effect.


Endokrynologia Polska | 2012

Analysis of the impact of environmental and social factors, with a particular emphasis on education, on the level of metabolic control in type 1 diabetes in children

Anna Stefanowicz; Dorota Birkholz; Małgorzata Myśliwiec; Maciej Niedźwiecki; Radosław Owczuk; Anna Balcerska

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Andrzej Kołtan

Nicolaus Copernicus University in Toruń

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Katarzyna Drabko

Medical University of Lublin

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Magdalena Ćwiklińska

Jagiellonian University Medical College

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Marcin Płonowski

Medical University of Białystok

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Maryna Krawczuk-Rybak

Medical University of Białystok

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Agnieszka Zaucha-Prażmo

Nicolaus Copernicus University in Toruń

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Jacek Wachowiak

Poznan University of Medical Sciences

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