Longin Niemczyk

Prof. Dr. Longin Niemczyk

orcid

Research Focus & Metrics

Academic Career Length

23Years (2004-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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14 June 2018 in BioMed Research International
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Journal Article
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KCKatarzyna Czarzasta
Katarzyna Czarzasta
ACAgnieszka Cudnoch-Jedrzejewska
Agnieszka Cudnoch-Jedrzejewska
LNLongin Niemczyk
Longin Niemczyk
RWRobert Wrzesien
Robert Wrzesien
Marcin TkaczykMarcin Tkaczyk
Marcin Tkaczyk
Stanisław NiemczykStanisław Niemczyk
Stanisław Niemczyk
It is believed that the vasopressinergic system plays an important role in the pathogenesis of chronic kidney disease (CKD). The aim of this study was to evaluate the effect of CKD on changes in vasopressin system expression in the kidney cortex in rats with nephrectomy. The study was performed on 4 groups of Sprague Dawley (SPRD) rats: a control group (CN), 1/2 nephrectomy (N1/2), 2/3 nephrectomy (N2/3), and 5/6 nephrectomy (N5/6). Blood and the kidney cortex were collected to evaluate plasma copeptin concentrations and mRNA expressions of V1a vasopressin receptors (V1aR) and V2 vasopressin receptors (V2R) and V1aR, V2R, and aquaporin 2 (AQP2) protein levels. V1aR and V2R mRNA expression in the kidney cortex was significantly lower in theCNgroup compared with the other groups. In contrast, the V1aR, V2R, and AQP2 protein levels were significantly higher in theCNgroup compared with all of the nephrectomized groups. Plasma copeptin concentration was significantly lower in theCNgroup than in the nephrectomized groups. CKD caused significant changes in the expression of the vasopressinergic system. Further research is needed to explain the mechanisms of the impact of the vasopressinergic system on the kidney in CKD.

14 January 2023 in Nutrients
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LNLongin Niemczyk
Longin Niemczyk
Katarzyna RomejkoKatarzyna Romejko
Katarzyna Romejko
KSKatarzyna Szamotulska
Katarzyna Szamotulska
DSDaniel Schneditz
Daniel Schneditz
Stanisław NiemczykStanisław Niemczyk
Stanisław Niemczyk
Background: Intradialytic hypotension (IDH) is a frequent complication of hemodialysis (HD). Current methods of IDH prevention are insufficient. Methods: We analyzed the intradialytic time course of systolic (SBP), diastolic (DBP), mean arterial (MAP), pulse pressure (PP), and heart rate (HR) in a group of chronic kidney disease (CKD) patients. First, 30 min into HD, a 40% glucose solution was injected into the venous line of the extracorporeal circulation at a dose of 0.5 g/kg of dry weight. Pressures and HR were measured in frequent intervals. Relative volume overload was determined by bioimpedance spectroscopy. Results: Thirty-five participants were studied. SBP increased after 5, 10, and 20 min of glucose infusion. DBP increased after 2 and 3 h and also at the end of HD. PP increased after 5, 10, and 20 min of glucose infusion and fell after the 2nd and 3rd hour and also at the end of HD. MAP increased after 2 and 3 h of glucose injection and at the end of HD. Significant interactions of the time course of SBP, DBP, MAP, with HR at baseline and of the time course of PP with fluid overload were observed. Symptomatic hypotensive episodes were absent. Conclusions: Glucose infusions during HD prevent symptomatic IDH and do not cause severe hypertensive episodes.

1 March 2021 in Diabetes Research and Clinical Practice
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Journal Article
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LNLongin Niemczyk
Longin Niemczyk
DSDaniel Schneditz
Daniel Schneditz
AWAnna Wojtecka
Anna Wojtecka
KSKatarzyna Szamotulska
Katarzyna Szamotulska
JSJerzy Smoszna
Jerzy Smoszna
Stanisław NiemczykStanisław Niemczyk
Stanisław Niemczyk
The disposal of a glucose bolus was studied to identify glucose metabolism in patients with and without type 2 diabetes mellitus (T2DM) during their regular hemodialysis (HD) treatment. Plasma glucose, insulin, and c-peptide concentrations were measured during a 60 min observation phase following a rapid glucose infusion (0.5g/kg dry weight). Glucose disposition and elimination rates were determined from kinetic analysis, and insulinogenic index was calculated. Insulin resistance (RHOMA) was determined by homeostatic model assessment (HOMA). 35 HD patients (14 with T2DM) distinguished by a higher age (median: 70 vs. 55 y, p<0.01) in T2DM patients were studied. Glucose kinetic data showed only small differences between patients with or without T2DM, but as RHOMA measured in all patients increased, a larger fraction of glucose was removed by the extracorporeal system (r=0.430, p=0.01). One hour after glucose bolus injection the glucose level was not different from that before HD also in patients with T2DM (p=0.115). The larger glucose amount recovered in dialysate in patients with increasing RHOMA indicates that impaired glucose disposal could be measured during HD using a non-invasive dialysis quantification approach without blood sampling. Glucose infusion during HD is safe also in patients with T2DM.

16 December 2022 in Nutrients
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Journal Article
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LNLongin Niemczyk
Longin Niemczyk
KBKatarzyna Buszko
Katarzyna Buszko
DSDaniel Schneditz
Daniel Schneditz
AWAnna Wojtecka
Anna Wojtecka
Katarzyna RomejkoKatarzyna Romejko
Katarzyna Romejko
Stanisław NiemczykStanisław Niemczyk
Stanisław Niemczyk
Background: The quality of autonomic blood pressure (BP) control can be assessed by the entropy of serial BP data. The aim of this study was to evaluate the effect of hemodialysis (HD) and glucose infusion (GI) on amplitude aware permutation entropy (AAPE) of hemodynamic variables during HD in chronic kidney disease patients with and without type-2 diabetes mellitus (DM). Methods: Twenty-one patients without DM (NDO) and ten with DM were studied. Thirty minutes after the start of HD, a 40% glucose solution was administered. Hemodynamic data were extracted from continuous recordings using the Portapres® system. Results: AAPE decreased during HD in all patients and all hemodynamic signals with the exception of AAPE of mean and diastolic BP in DM patients. GI led to an increase in AAPE for cardiac output in all patients, while AAPE for heart rate and ejection time increased only in DM studies, and AAPE for systolic, diastolic, and mean arterial pressure, as well as total peripheral resistance, increased only in NDO patients. Conclusions: The reduction in entropy during HD indicates impaired autonomic control in response to external perturbations. This state is partially reversed by the infusion of glucose with differences in central and peripheral responsiveness in DM and NDO patients.

1 January 2012
Verified
Journal Article
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Stanisław NiemczykStanisław Niemczyk
Stanisław Niemczyk
LNLongin Niemczyk
Longin Niemczyk
KRKatarzyna Romejko-Ciepielewska
Katarzyna Romejko-Ciepielewska

1 January 2021 in Oxidative Medicine and Cellular Longevity
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Journal Article
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LNLongin Niemczyk
Longin Niemczyk
Jolanta MałyszkoJolanta Małyszko
Jolanta Małyszko
Nowadays, the high prevalence of kidney diseases and their related complications, including endothelial dysfunction and cardiovascular disease, represents one of the leading causes of death in patients with chronic kidney diseases. Renal failure leads to accumulation of uremic toxins, which are the main cause of oxidative stress development. The renal replacement therapy appears to be the best way to lower uremic toxin levels in patients with end‐stage renal disease and reduce oxidative stress. At this moment, despite the increasing number of recognized toxins and their mechanisms of action, it is impossible to determine which of them are the most important and which cause the greatest complications. There are many different types of renal replacement therapy, but the best treatment has not been identified yet. Patients treated with diffusion methods have satisfactory clearance of small molecules, but the clearance of medium molecules appears to be insufficient, but treatment with convection methods cleans medium molecules better than small molecules. Hence, there is an urgent need of new more validated, appropriate, and reliable information not only on toxins and their role in metabolic disorders, including oxidative stress, but also on the best artificial renal replacement therapy to reduce complications and prolong the life of patients with chronic kidney disease.