Łukasz Zdzisław Michałowski

Łukasz Zdzisław Michałowski

Department of Pathology, Medical University of Warsaw, Warsaw, Mazowieckie, Poland
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Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

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

Representative Publications

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9 August 2018 in International Journal of Computer Assisted Radiology and Surgery
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MBMichal Byra
Michal Byra
GSGrzegorz Styczynski
Grzegorz Styczynski
CSCezary Szmigielski
Cezary Szmigielski
PKPiotr Kalinowski
Piotr Kalinowski
ŁMŁukasz Zdzisław Michałowski
Łukasz Zdzisław Michałowski
ANAndrzej Nowicki
Andrzej Nowicki
Purpose The nonalcoholic fatty liver disease is the most common liver abnormality. Up to date, liver biopsy is the reference standard for direct liver steatosis quantification in hepatic tissue samples. In this paper we propose a neural network-based approach for nonalcoholic fatty liver disease assessment in ultrasound. Methods We used the Inception-ResNet-v2 deep convolutional neural network pre-trained on the ImageNet dataset to extract high-level features in liver B-mode ultrasound image sequences. The steatosis level of each liver was graded by wedge biopsy. The proposed approach was compared with the hepatorenal index technique and the gray-level co-occurrence matrix algorithm. After the feature extraction, we applied the support vector machine algorithm to classify images containing fatty liver. Based on liver biopsy, the fatty liver was defined to have more than 5% of hepatocytes with steatosis. Next, we used the features and the Lasso regression method to assess the steatosis level. Results The area under the receiver operating characteristics curve obtained using the proposed approach was equal to 0.977, being higher than the one obtained with the hepatorenal index method, 0.959, and much higher than in the case of the gray-level co-occurrence matrix algorithm, 0.893. For regression the Spearman correlation coefficients between the steatosis level and the proposed approach, the hepatorenal index and the gray-level co-occurrence matrix algorithm were equal to 0.78, 0.80 and 0.39, respectively. Conclusions The proposed approach may help the sonographers automatically diagnose the amount of fat in the liver. The presented approach is efficient and in comparison with other methods does not require the sonographers to select the region of interest.

9 November 2020 in Brain Structure and Function
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TDTomasz Andrzej Dziedzic
Tomasz Andrzej Dziedzic
ABArtur Balasa
Artur Balasa
MJMateusz P. Jeżewski
Mateusz P. Jeżewski
ŁMŁukasz Zdzisław Michałowski
Łukasz Zdzisław Michałowski
AMAndrzej Marchel
Andrzej Marchel
The aim of this literature review is to present a summary of the published literature relating the details of the different modifications of specimen preparation for white matter dissection with the Klingler technique. For this review, 3 independent investigators performed an electronic literature search that was carried out in the Pubmed, Scopus and Web of Science databses up to December 2019. Furthermore, we performed citation tracking for the articles missed in the initial search. Studies were eligible for inclusion when they reported details of at least the first 2 main steps of Klingler’s technique: fixation and freezing. A total of 37 full-text articles were included in the analysis. We included original anatomical studies in which human white matter dissection was performed for study purposes. The main three steps of preparation are the same in each laboratory, but the details of each vary between studies. Ten percent formalin is the most commonly used (34 studies) solution for fixation. The freezing time varied between 8 h and a month, and the temperature varied from − 5 to − 80 °C. After thawing and during dissections, the specimens were most often kept in formalin solution (13), and the concentration varied from 4 to 10%. Klingler’s preparation technique involves three main steps: fixation, freezing and thawing. Even though the details of the technique are different in most of the studies, all provide subjectively good quality specimens for anatomical dissections and studies.

20 April 2021 in Journal of the American Heart Association
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GSGrzegorz Styczynski
Grzegorz Styczynski
PKPiotr Kalinowski
Piotr Kalinowski
ŁMŁukasz Zdzisław Michałowski
Łukasz Zdzisław Michałowski
RPRafał Paluszkiewicz
Rafał Paluszkiewicz
BZBogna Ziarkiewicz‐Wróblewska
Bogna Ziarkiewicz‐Wróblewska
MSMaciej Sinski
Maciej Sinski
Background: The patients with nonalcoholic fatty liver disease demonstrate an increased cardiovascular risk. The adverse influence of liver abnormalities on cardiac function are among many postulated mechanisms behind this association. The aim of the study was to evaluate cardiac morphology and function in patients with morbid obesity referred for bariatric surgery with liver biopsy. Methods and Results: We evaluated with echocardiography 171 consecutive patients without known cardiac disease (median age 42 [interquartile range, 37–48] years, median body mass index 43.7 [interquartile range, 41.0–47.5], 67% female patients. Based on the liver biopsy results, there were 44 patients with nonalcoholic steatohepatitis (NASH), 69 patients with isolated steatosis, and 58 patients without steatosis. Patients with NASH demonstrated signs of left ventricular concentric remodeling and hyperdynamic circulation, including indexed left ventricular end‐diastolic diameter [cm/m 2 ]: NASH 1.87 [0.22]; isolated steatosis 2.03 [0.33]; without steatosis 2.01 [0.19], P =0.001; relative wall thickness: NASH 0.49±0.05, isolated steatosis 0.47±0.06, without steatosis 0.46±0.06, P =0.011; cardiac index [L/m 2 ]: NASH 3.05±0.54, isolated steatosis 2.80±0.44, without steatosis 2.79±0.50, P =0.013. After adjustment for sex, age, blood pressure, and heart rate, most of the measures of the left ventricular systolic and diastolic function, left atrial size, right ventricular function, and right ventricular size did not differ between groups. Conclusions: In a group of patients with extreme obesity, NASH was associated with left ventricular concentric remodeling and hyperdynamic circulation. Increased cardiac output in NASH may represent an additional risk factor for incident cardiovascular events in this population.

Verified
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PKPiotr Kalinowski
Piotr Kalinowski
WSWiktor Smyk
Wiktor Smyk
MNMałgorzata Nowosad
Małgorzata Nowosad
RPRafał Paluszkiewicz
Rafał Paluszkiewicz
ŁMŁukasz Zdzisław Michałowski
Łukasz Zdzisław Michałowski
MKMarcin Krawczyk
Marcin Krawczyk
The severity of hepatic steatosis is modulated by genetic variants, such as patatin-like phospholipase domain containing 3 (PNPLA3) rs738409, transmembrane 6 superfamily member 2 (TM6SF2) rs58542926, and membrane-bound O-acyltransferase domain containing 7 (MBOAT7) rs641738. Recently, mitochondrial amidoxime reducing component 1 (MTARC1) rs2642438 and hydroxysteroid 17-beta dehydrogenase 13 (HSD17B13) rs72613567 polymorphisms were shown to have protective effects on liver diseases. Here, we evaluate these variants in patients undergoing bariatric surgery. A total of 165 patients who underwent laparoscopic sleeve gastrectomy and intraoperative liver biopsies and 314 controls were prospectively recruited. Genotyping was performed using TaqMan assays. Overall, 70.3% of operated patients presented with hepatic steatosis. NASH (non-alcoholic steatohepatitis) was detected in 28.5% of patients; none had cirrhosis. The increment of liver fibrosis stage was associated with decreasing frequency of the MTARC1 minor allele (p = 0.03). In multivariate analysis MTARC1 was an independent protective factor against fibrosis ≥ 1b (OR = 0.52, p = 0.03) and ≥ 1c (OR = 0.51, p = 0.04). The PNPLA3 risk allele was associated with increased hepatic steatosis, fibrosis, and NASH (OR = 2.22, p = 0.04). The HSD17B13 polymorphism was protective against liver injury as reflected by lower AST (p = 0.04) and ALT (p = 0.03) activities. The TM6SF2 polymorphism was associated with increased ALT (p = 0.04). In conclusion, hepatic steatosis is common among patients scheduled for bariatric surgery, but the MTARC1 and HSD17B13 polymorphisms lower liver injury in these individuals.

24 September 2018 in Folia Histochemica et Cytobiologica
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BGBarbara Grzechocinska
Barbara Grzechocinska
FDFilip Andrzej Dabrowski
Filip Andrzej Dabrowski
ACAnna Cyganek
Anna Cyganek
MCMarcin Chlebus
Marcin Chlebus
CKChristopher Kobierzycki
Christopher Kobierzycki
MWMiroslaw Wielgos
Miroslaw Wielgos
Introduction. Endometrium undergoes regular, cyclic tissue remodeling mostly associated to the endocrine system status. It is well-known fact that steroid hormones are strongly responsible for changes in endometrium. The precise mechanism of their action is still under investigation. The aim of the study was to evaluate the expression of metalloproteinases 2 and 7 (MMP-2, -7) and tissue inhibitor of metalloproteinase 1 (TIMP-1) in human endometrium in relation to serum concentrations of estradiol and progesterone during different phases of menstrual cycle. Material and methods. The study material consisted of 52 biopsy samples; 12 obtained in the proliferative phase, 11 in the secretory phase and 29 during menstruation. Expression of MMP-2, MMP-7 and TIMP-1 was assessed by immunohistochemistry. Serum concentrations of estradiol and progesterone at time of biopsy were evaluated by immunochemistry assay. Results of the study were statistically assessed by linear regression model. Results. Increased serum concentration of estradiol was associated with increased MMP-2 expression in proliferative phase but decreased in secretory phase and during menstruation. No significant relationship was found between progesterone concentration and MMP-2 expression. Moreover, no difference in the expression of MMP-7 and TIMP-1 in the endometrium in relation to hormone levels and menstrual cycle phases were observed. Conclusions. The results of the study indicate that estradiol influence MMP-2 expression in the endometrium depends on the phase of menstrual cycle. Such relationships were not found for MMP-7 and TIMP-1 and further tests clarifying association between estradiol and MMPs are needed. Introduction. Endometrium undergoes regular, cyclic tissue remodeling mostly associated to the endocrine system status. It is well-known fact that steroid hormones are strongly responsible for changes in endometrium. The precise mechanism of their action is still under investigation. The aim of the study was to evaluate the expression of metalloproteinases 2 and 7 (MMP-2, -7) and tissue inhibitor of metalloproteinase 1 (TIMP-1) in human endometrium in relation to serum concentrations of estradiol and progesterone during different phases of menstrual cycle. Material and methods. The study material consisted of 52 biopsy samples; 12 obtained in the proliferative phase, 11 in the secretory phase and 29 during menstruation. Expression of MMP-2, MMP-7 and TIMP-1 was assessed by immunohistochemistry. Serum concentrations of estradiol and progesterone at time of biopsy were evaluated by immunochemistry assay. Results of the study were statistically assessed by linear regression model. Results. Increased serum concentration of estradiol was associated with increased MMP-2 expression in proliferative phase but decreased in secretory phase and during menstruation. No significant relationship was found between progesterone concentration and MMP-2 expression. Moreover, no difference in the expression of MMP-7 and TIMP-1 in the endometrium in relation to hormone levels and menstrual cycle phases were observed. Conclusions. The results of the study indicate that estradiol influence MMP-2 expression in the endometrium depends on the phase of menstrual cycle. Such relationships were not found for MMP-7 and TIMP-1 and further tests clarifying association between estradiol and MMPs are needed.

1 August 2019 in Atherosclerosis
Verified
Journal Article
Closed access
GSGrzegorz Styczyński
Grzegorz Styczyński
PKPiotr Kalinowski
Piotr Kalinowski
ŁMŁukasz Zdzisław Michałowski
Łukasz Zdzisław Michałowski
RPRafał Paluszkiewicz
Rafał Paluszkiewicz
BZBogna Ziarkiewicz-Wróblewska
Bogna Ziarkiewicz-Wróblewska
PJPiotr Jedrusik
Piotr Jedrusik