Jan Křemen

Dr. Jan Křemen

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Research Focus & Metrics

Academic Career Length

8Years (2019-Present)

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

Representative Publications

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12 December 2019 in Scientific Reports
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Petra FrýdlováPetra Frýdlová
Petra Frýdlová
JMJana Mrzílková
Jana Mrzílková
MŠMartin Šeremeta
Martin Šeremeta
JKJan Křemen
Jan Křemen
JDJan Dudak
Jan Dudak
PZPetr Zach
Petr Zach
Squamate reptiles are considered to exhibit indeterminate growth. Nevertheless, current literature disputes the available definitions of this growth type, presents new theoretical models, and questions its universality in cold-blooded vertebrates. We have followed up on our previous research employing micro-CT to explore growth plate cartilage (GPC) in the epiphysis of long bones, which is responsible for longitudinal skeletal growth by the endochondral ossification process. We focused on numerous and highly diversified group of the Iguania clade comprising Acrodonta (agamas and chameleons) and Pleurodonta (“iguanas”). We recorded the absence of GPC in most of the examined adult Pleurodonta specimens and interpret it as an irreversible arrest of skeletal growth. This finding clearly rejects the universality of indeterminate growth in lizards. On the other hand, we found apparent GPC preservation in most of the adult specimens belonging to Acrodonta. This suggests a preserved ability to continue body growth throughout most of their life. We discuss the uncovered disparity between Acrodonta and Pleurodonta and emphasize the importance of GPC degradation timing.

23 April 2023 in Cells
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Journal Article
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ZWZdeněk Wurst
Zdeněk Wurst
BKBarbora Birčák Kuchtová
Barbora Birčák Kuchtová
JKJan Křemen
Jan Křemen
ALAnastasiya Lahutsina
Anastasiya Lahutsina
Ibrahim IbrahimIbrahim Ibrahim
Ibrahim Ibrahim
JMJana Mrzílková
Jana Mrzílková
The volume reduction of the gray matter structures in patients with Alzheimer’s disease is often accompanied by an asymmetric increase in the number of white matter fibers located close to these structures. The present study aims to investigate the white matter structure changes in the motor basal ganglia in Alzheimer’s disease patients compared to healthy controls using diffusion tensor imaging. The amounts of tracts, tract length, tract volume, quantitative anisotropy, and general fractional anisotropy were measured in ten patients with Alzheimer’s disease and ten healthy controls. A significant decrease in the number of tracts and general fractional anisotropy was found in patients with Alzheimer’s disease compared to controls in the right caudate nucleus, while an increase was found in the left and the right putamen. Further, a significant decrease in the structural volume of the left and the right putamen was observed. An increase in the white matter diffusion tensor imaging parameters in patients with Alzheimer’s disease was observed only in the putamen bilaterally. The right caudate showed a decrease in both the diffusion tensor imaging parameters and the volume in Alzheimer’s disease patients. The right pallidum showed an increase in the diffusion tensor imaging parameters but a decrease in volume in Alzheimer’s disease patients.

1 January 2020 in BioMed Research International
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Journal Article
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JMJ Mrzilkova
J Mrzilkova
PMP Michenka
P Michenka
MSM Seremeta
M Seremeta
JKJan Křemen
Jan Křemen
JDJ Dudak
J Dudak
PZPetr Zach
Petr Zach
We performed micro‐CT imaging of the vascular blood supply in the interscapular area of the brown adipose tissue in three mice with the use of intravascular contrast agent Aurovist™. Resulting 3D data rendering was then adapted into 2D resolution with visualization using false color system and grayscale images. These were then studied for the automatic quantification of the blood vessel density within this area. We found the highest most occurring density within arterioles or venules representing smaller blood vessels whereas with the increase of the vessel diameters a lower percentage rate of their presence was observed in the sample. Our study shows that micro‐CT scanning in combination with Aurovist™ contrast is suitable for anatomical studies of interscapular area of brown adipose tissue blood vessel supply.