Publications by authors named "Sergei Kuznetsov"

80 Publications

Can Radiographic Tumor Volume of Oral Squamous Cell Carcinoma Help Predict Clinical and Pathological Tumor Features?

J Oral Maxillofac Surg 2021 Jun 12. Epub 2021 Jun 12.

Associate Professor, Department of Oral and Maxillofacial Surgery, Louisiana State University Health Sciences Center, New Orleans, LA.

Purpose: Radiographic tumor volume (RTV) of oral squamous cell carcinoma (SCC) is seldom measured in practice. Aims of the study are to estimate RTV of SCC and to investigate its relationship with clinical and pathological stage, tumor margin status, recurrence, and need for chemo/radiation.

Methods: The design is a retrospective cohort study. The predictor variable is SCC RTV. The primary outcome variables are clinical and pathological tumor size. The secondary outcomes are margin status and postoperative chemo/radiation. Tumor dimensions were measured on preoperative maxillofacial or neck computer tomography images with contrast. Information on patient and tumor characteristics was obtained. Pearson correlation, t test, ANOVA and log rank test were used for statistical analysis. The significance level was set at .05.

Results: Thirty-six subjects aged 36 to 86 were included in the study. Positive association was found between clinical T stage and RTV (P = .0003) and between pathologic T stage and RTV (P = .002). Mean value of RTV was significantly higher in the group with positive margins (P = .0004). RTV was significantly higher in cancers requiring adjuvant chemo/radiation (P = .033). Mean RTV for patients with recurrence was 1.86 cm as compared to 1.29 cm for patients with no recurrence. Higher tumor volumes were more likely to be associated with recurrence.

Conclusions: RTV is a variable that is readily available to head and neck surgeons. RTV is associated with clinical and pathological tumor sizes, margin status, need for adjuvant chemo/radiation and tumor recurrence.
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http://dx.doi.org/10.1016/j.joms.2021.06.012DOI Listing
June 2021

Fluorescent bacterial biosensor /pTdcR-TurboYFP sensitive to terahertz radiation.

Biomed Opt Express 2021 Feb 5;12(2):705-721. Epub 2021 Jan 5.

Laboratory of Molecular Biotechnologies of Federal research center Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences, 10 Lavrentiev Aven., Novosibirsk, 630090, Russia.

A fluorescent biosensor /pTdcR-TurboYFP sensitive to terahertz (THz) radiation was developed via transformation of () cells with plasmid, in which the promotor of the gene controls the expression of yellow fluorescent protein TurboYFP. The biosensor was exposed to THz radiation in various vessels and nutrient media. The threshold and dynamics of fluorescence were found to depend on irradiation conditions. Heat shock or chemical stress yielded the absence of fluorescence induction. The biosensor is applicable to studying influence of THz radiation on the activity of promotor that is involved in the transport and metabolism of threonine and serine in .
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http://dx.doi.org/10.1364/BOE.412074DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7901329PMC
February 2021

Bone Marrow Stromal Cell Assays: In Vitro and In Vivo.

Methods Mol Biol 2021 ;2230:379-396

Sapienza University of Rome, Rome, Italy.

Populations of bone marrow stromal cells (BMSCs, also known as bone marrow-derived "mesenchymal stem cells") contain a subset of cells that are able to recapitulate the formation of a bone/marrow organ (skeletal stem cells, SSCs). It is now apparent that cells with similar but not identical properties can be isolated from other skeletal compartments (growth plate, periosteum). The biological properties of BMSCs, and these related stem/progenitor cells, are assessed by a variety of assays, both in vitro and in vivo. Application of these assays in an appropriate fashion provide a great deal of information on the role of BMSCs, and the subset of SSCs, in health and in disease.
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http://dx.doi.org/10.1007/978-1-0716-1028-2_23DOI Listing
March 2021

The Post-Translational Modifications, Localization, and Mode of Attachment of Non-Covalently Bound Glucanosyltransglycosylases of Yeast Cell Wall as a Key to Understanding their Functioning.

Int J Mol Sci 2020 Nov 5;21(21). Epub 2020 Nov 5.

Department of Molecular Biology, Faculty of Biology, Lomonosov Moscow State University, Moscow 119991, Russia.

Glucan linked to proteins is a natural mega-glycoconjugate (mGC) playing the central role as a structural component of a yeast cell wall (CW). Regulation of functioning of non-covalently bound glucanosyltransglycosylases (ncGTGs) that have to remodel mGC to provide CW extension is poorly understood. We demonstrate that the main ncGTGs Bgl2 and Scw4 have phosphorylated and glutathionylated residues and are represented in CW as different pools of molecules having various firmness of attachment. Identified pools contain Bgl2 molecules with unmodified peptides, but differ from each other in the presence and combination of modified ones, as well as in the presence or absence of other CW proteins. Correlation of Bgl2 distribution among pools and its N-glycosylation was not found. Glutathione affects Bgl2 conformation, probably resulting in the mode of its attachment and enzymatic activity. Bgl2 from the pool of unmodified and monophosphorylated molecules demonstrates the ability to fibrillate after isolation from CW. Revealing of Bgl2 microcompartments and their mosaic arrangement summarized with the results obtained give the evidence that the functioning of ncGTGs in CW can be controlled by reversible post-translational modifications and facilitated due to their compact localization. The hypothetical scheme of distribution of Bgl2 inside CW is represented.
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http://dx.doi.org/10.3390/ijms21218304DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7663962PMC
November 2020

Temperature Sensing in the Short-Wave Infrared Spectral Region Using Core-Shell NaGdF:Yb, Ho, [email protected] Nanothermometers.

Nanomaterials (Basel) 2020 Oct 9;10(10). Epub 2020 Oct 9.

Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow,119991, Russia.

The short-wave infrared region (SWIR) is promising for deep-tissue visualization and temperature sensing due to higher penetration depth and reduced scattering of radiation. However, the strong quenching of luminescence in biological media and low thermal sensitivity of nanothermometers in this region are major drawbacks that limit their practical application. Nanoparticles doped with rare-earth ions are widely used as thermal sensors operating in the SWIR region through the luminescence intensity ratio (LIR) approach. In this study, the effect of the shell on the sensitivity of temperature determination using NaGdF nanoparticles doped with rare-earth ions (REI) Yb, Ho, and Er coated with an inert NaYF shell was investigated. We found that coating the nanoparticles with a shell significantly increases the intensity of luminescence in the SWIR range, prevents water from quenching luminescence, and decreases the temperature of laser-induced heating. Thermometry in the SWIR spectral region was demonstrated using synthesized nanoparticles in dry powder and in water. The core-shell nanoparticles obtained had intense luminescence and made it possible to determine temperatures in the range of 20-40 °C. The relative thermal sensitivity of core-shell NPs was 0.68% °C in water and 4.2% °C in dry powder.
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http://dx.doi.org/10.3390/nano10101992DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7601673PMC
October 2020

Study on the effects of terahertz radiation on gene networks of by means of fluorescent biosensors.

Biomed Opt Express 2020 Sep 25;11(9):5258-5273. Epub 2020 Aug 25.

Laboratory of Molecular Biotechnologies of Federal Research Center Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences, 10 Lavrentiev Avenue, Novosibirsk 630090, Russia.

Three novel fluorescent biosensors sensitive to terahertz (THz) radiation were developed via transformation of () cells with plasmids, in which a promotor of genes , , or controls the expression of a fluorescent protein. The biosensors were exposed to THz radiation from two sources: a high-intensity pulsed short-wave free electron laser and a low-intensity continuous long-wave IMPATT-diode-based device. The threshold and dynamics of fluorescence were found to depend on radiation parameters and exposure time. Heat shock or chemical stress yielded the absence of fluorescence induction. The biosensors are evaluated to be suitable for studying influence of THz radiation on the activity of gene networks related with considered gene promoters.
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http://dx.doi.org/10.1364/BOE.400432DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7510871PMC
September 2020

Optimization of upconversion luminescence excitation mode for deeper in vivo bioimaging without contrast loss or overheating.

Methods Appl Fluoresc 2020 Mar 2;8(2):025006. Epub 2020 Mar 2.

Prokhorov General Physics Institute of the Russian Academy of Sciences, Vavilova Str. 38, Moscow, 119991, Russia.

Upconversion nanoparticles have attracted considerable attention as luminescent markers for bioimaging and sensing due to their capability to convert near-infrared (NIR) excitation into visible or NIR luminescence. However, the wavelength of about 970 nm is commonly used for the upconversion luminescence excitation, where the strong absorption of water is observed, which can lead to laser-induced overheating effects. One of the strategies for avoiding such laser-induced heating involves shifting the excitation into shorter wavelengths region. However, the influence of wavelength change on luminescent images quality has not been investigated yet. In this work, we compare wavelengths of 920, 940 and 970 nm for upconversion luminescence excitation in the thickness of biological tissues in terms of detected signal intensity and obtained image quality (contrast and signal-to-background ratio). Studies on biological tissue phantoms with various scattering and absorbing properties were performed to analyze the influence of optical parameters on the depth and contrast of the images obtained under 920-970 nm excitation. It was shown that at the same power the excitation wavelength shift reduces the detected signal intensity and the resulting image contrast. Visualization of biological tissue samples using shorter excitation wavelengths 920 and 940 nm also reduces signal-to-background ratio (S/B) of the obtained images. The S/B of the obtained images amounted to 2, 6 and 8 for 920, 940 and 970 nm, respectively. It was demonstrated that pulse-periodic excitation mode is preferable for obtaining high quality luminescent images of biological tissues deep layers and minimize overheating. Short pulse durations (duty cycle 20%) don't result in heating even for 1 W cm pumping power density and allow obtaining high luminescence intensity, which provides good images quality.
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http://dx.doi.org/10.1088/2050-6120/ab7782DOI Listing
March 2020

Labyrinth Metasurface for Biosensing Applications: Numerical Study on the New Paradigm of Metageometries.

Sensors (Basel) 2019 Oct 11;19(20). Epub 2019 Oct 11.

Antennas Group-TERALAB, Universidad Pública de Navarra, Campus Arrosadía, 31006 Pamplona, Spain.

The use of metasurfaces operating in the terahertz regime as biosensor devices has attracted increased interest in recent years due to their enhanced sensitivity and more accurate detection capability. Typical designs are based on the replica of relatively simple unit cells, usually called metaatoms. In a previous paper, we proposed a new paradigm for ultrasensitive thin-film sensors based on complex unit cells, called generically metageometries or labyrinth metasurfaces. Here, we extend this concept towards biosensing, evaluating the performance of the labyrinth as a fungi detector. The sensing capabilities are numerically evaluated and a comparison with previous works in this field is performed, showing that metageometries improve the performance compared to metaatoms both in sensitivity and figure of merit, by a factor of more than four. In particular, we find that it is able to detect five fungi elements scattered on the unit cell, equivalent to a concentration of only 0.004/µm.
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http://dx.doi.org/10.3390/s19204396DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6833032PMC
October 2019

OCT-elastography-based optical biopsy for breast cancer delineation and express assessment of morphological/molecular subtypes.

Biomed Opt Express 2019 May 4;10(5):2244-2263. Epub 2019 Apr 4.

Privolzhsky Research Medical University, Nizhny Novgorod, Russia.

Application of compressional optical coherence elastography (OCE) for delineation of tumor and peri-tumoral tissue with simultaneous assessment of morphological/molecular subtypes of breast cancer is reported. The approach is based on the ability of OCE to quantitatively visualize stiffness of studied samples and then to perform a kind of OCE-based biopsy by analyzing elastographic B-scans that have sizes ~several millimeters similarly to bioptates used for "gold-standard" histological examinations. The method relies on identification of several main tissue constituents differing in their stiffness in the OCE scans. Initially the specific stiffness ranges for the analyzed tissue components (adipose tissue, fibrous and hyalinized tumor stroma, lymphocytic infiltrate and agglomerates of tumor cells) are determined via comparison of OCE and morphological/molecular data. Then assessment of non-tumor/tumor regions and tumor subtypes is made based on percentage of pixels with different characteristic stiffness ("stiffness spectrum") in the OCE image, also taking into account spatial localization of different-stiffness regions. Examples of high contrast among benign (or non-invasive) and several subtypes of invasive breast tumors in terms of their stiffness spectra are given.
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http://dx.doi.org/10.1364/BOE.10.002244DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6524573PMC
May 2019

Reduced vs. standard dose native E. coli-asparaginase therapy in childhood acute lymphoblastic leukemia: long-term results of the randomized trial Moscow-Berlin 2002.

J Cancer Res Clin Oncol 2019 Apr 6;145(4):1001-1012. Epub 2019 Mar 6.

Department of Pediatric Oncology/Hematology, Regional Oncological Hospital, Orenburg, Russia.

Purpose: Favorable outcomes were achieved for children with acute lymphoblastic leukemia (ALL) with the first Russian multicenter trial Moscow-Berlin (ALL-MB) 91. One major component of this regimen included a total of 18 doses of weekly intramuscular (IM) native Escherichia coli-derived asparaginase (E. coli-ASP) at 10000 U/m during three consolidation courses. ASP was initially available from Latvia, but had to be purchased from abroad at substantial costs after the collapse of Soviet Union. Therefore, the subsequent trial ALL-MB 2002 aimed at limiting costs to a reasonable extent and also at reducing toxicity by lowering the dose for standard risk (SR-) patients to 5000 U/m without jeopardizing efficacy.

Methods: Between April 2002 and November 2006, 774 SR patients were registered in 34 centers across Russia and Belarus, 688 of whom were randomized. In arm ASP-5000 (n = 334), patients received 5000 U/m and in arm ASP-10000 (n = 354) 10 000 U/m IM.

Results: Probabilities of disease-free survival, overall survival and cumulative incidence of relapse at 10 years were comparable: 79 ± 2%, 86 ± 2% and 17.4 ± 2.1% (ASP-5000) vs. 75 ± 2% and 82 ± 2%, and 17.9 ± 2.0% (ASP-10000), while death in complete remission was significantly lower in arm ASP-5000 (2.7% vs. 6.5%; p = 0.029).

Conclusion: Our findings suggest that weekly 5000 U/mE. coli-ASP IM during consolidation therapy are equally effective, more cost-efficient and less toxic than 10000 U/m for SR patients with childhood ALL.
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http://dx.doi.org/10.1007/s00432-019-02854-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6435612PMC
April 2019

In Vivo Formation of Stable Hyaline Cartilage by Naïve Human Bone Marrow Stromal Cells with Modified Fibrin Microbeads.

Stem Cells Transl Med 2019 06 14;8(6):586-592. Epub 2019 Feb 14.

Biotechnology and Radiobiology Laboratory, Hadassah - Hebrew University Medical Center, Sharett Institute of Oncology, Jerusalem, Israel.

Osteoarthritic and other types of articular cartilage defects never heal on their own. Medicinal and surgical approaches are often ineffective, and the supply of autologous chondrocytes for tissue engineering is very limited. Bone marrow stromal cells (BMSCs, also known as bone marrow-derived mesenchymal stem cells) have been suggested as an adequate cell source for cartilage reconstruction. However, the majority of studies employing BMSCs for cartilage tissue engineering have used BMSCs predifferentiated into cartilage prior to implantation. This strategy has failed to achieve formation of stable, hyaline-like cartilage, resistant to hypertrophy in vivo. We hypothesized that in vitro predifferentiation of BMSCs is not necessary when cells are combined with an adequate scaffold that supports the formation of stable cartilage in vivo. In this study, naïve (undifferentiated) human BMSCs were attached to dehydrothermally crosslinked stable fibrin microbeads (FMBs) without and with other scaffolds and implanted subcutaneously into immunocompromised mice. Optimal formation of abundant, hypertrophy-resistant, ectopic hyaline-like cartilage was achieved when BMSCs were attached to FMBs covalently coated with hyaluronic acid. The cartilage that was formed was of human origin and was stable for at least 28 weeks in vivo. Stem Cells Translational Medicine 2019;8:586-592.
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http://dx.doi.org/10.1002/sctm.18-0129DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6525579PMC
June 2019

THz Sensing With Anomalous Extraordinary Optical Transmission Hole Arrays.

Sensors (Basel) 2018 Nov 9;18(11). Epub 2018 Nov 9.

Antennas Group-TERALAB, Universidad Pública de Navarra, Campus Arrosadía, 31006 Pamplona, Spain.

Subwavelength hole array (HA) metasurfaces support the so-called extraordinary optical transmission (EOT) resonance that has already been exploited for sensing. In this work, we demonstrate the superior performance of a different resonant regime of HA metasurfaces called anomalous EOT, by doing a thorough numerical and experimental study of its ability in thin-film label-free sensing applications in the terahertz (THz) band. A comprehensive analysis using both the regular and anomalous EOT resonances is done by depositing thin layers of dielectric analyte slabs of different thicknesses on the structures in different scenarios. We carry out a detailed comparison and demonstrate that the best sensing performance is achieved when the structure operates in the anomalous EOT resonance and the analyte is deposited on the non-patterned side of the metasurface, improving by a factor between 2 and 3 the results of the EOT resonance in any of the considered scenarios. This can be explained by the comparatively narrower linewidth of the anomalous EOT resonance. The results presented expand the reach of subwavelength HAs for sensing applications by considering the anomalous EOT regime that is usually overlooked in the literature.
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http://dx.doi.org/10.3390/s18113848DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6263774PMC
November 2018

Nanoantenna structures for the detection of phonons in nanocrystals.

Beilstein J Nanotechnol 2018 5;9:2646-2656. Epub 2018 Oct 5.

Semiconductor Physics, Technische Universitaet Chemnitz, 09126, Chemnitz, Germany.

We report a study of the infrared response by localized surface plasmon resonance (LSPR) modes in gold micro- and nanoantenna arrays with various morphologies and surface-enhanced infrared absorption (SEIRA) by optical phonons of semiconductor nanocrystals (NCs) deposited on the arrays. The arrays of nano- and microantennas fabricated with nano- and photolithography reveal infrared-active LSPR modes of energy ranging from the mid to far-infrared that allow the IR response from very low concentrations of organic and inorganic materials deposited onto the arrays to be analyzed. The Langmuir-Blodgett technology was used for homogeneous deposition of CdSe, CdS, and PbS NC monolayers on the antenna arrays. The structural parameters of the arrays were confirmed by scanning electron microscopy. 3D full-wave electromagnetic simulations of the electromagnetic field distribution around the micro- and nanoantennas were employed to realize the maximal SEIRA enhancement for structural parameters of the arrays whereby the LSPR and the NC optical phonon energies coincide. The SEIRA experiments quantitatively confirmed the computational results. The maximum SEIRA enhancement was observed for linear nanoantennas with optimized structural parameters determined from the electromagnetic simulations. The frequency position of the feature's absorption seen in the SEIRA response evidences that the NC surface and transverse optical phonons are activated in the infrared spectra.
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http://dx.doi.org/10.3762/bjnano.9.246DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6204786PMC
October 2018

Combinatorial cassettes to systematically evaluate tissue-engineered constructs in recipient mice.

Biomaterials 2018 12 24;186:31-43. Epub 2018 Sep 24.

Biosystems & Biomaterials Division, National Institute of Standards & Technology, Gaithersburg, MD, USA. Electronic address:

Ectopic bone formation in mice is the gold standard for evaluation of osteogenic constructs. By regular procedures, usually only 4 constructs can be accommodated per mouse, limiting screening power. Combinatorial cassettes (combi-cassettes) hold up to 19 small, uniform constructs from the time of surgery, through time in vivo, and subsequent evaluation. Two types of bone tissue engineering constructs were tested in the combi-cassettes: i) a cell-scaffold construct containing primary human bone marrow stromal cells with hydroxyapatite/tricalcium phosphate particles (hBMSCs + HA/TCP) and ii) a growth factor-scaffold construct containing bone morphogenetic protein 2 in a gelatin sponge (BMP2+GS). Measurements of bone formation by histology, bone formation by X-ray microcomputed tomography (μCT) and gene expression by quantitative polymerase chain reaction (qPCR) showed that constructs in combi-cassettes were similar to those created by regular procedures. Combi-cassettes afford placement of multiple replicates of multiple formulations into the same animal, which enables, for the first time, rigorous statistical assessment of: 1) the variability for a given formulation within an animal (intra-animal variability), 2) differences between different tissue-engineered formulations within the same animal and 3) the variability for a given formulation in different animals (inter-animal variability). Combi-cassettes enable a more high-throughput, systematic approach to in vivo studies of tissue engineering constructs.
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http://dx.doi.org/10.1016/j.biomaterials.2018.09.035DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6282169PMC
December 2018

Nanoantenna-assisted plasmonic enhancement of IR absorption of vibrational modes of organic molecules.

Beilstein J Nanotechnol 2017 3;8:975-981. Epub 2017 May 3.

Semiconductor Physics, Technische Universität Chemnitz, D-09107 Chemnitz, Germany.

Nanoantenna-assisted plasmonic enhancement of IR absorption and Raman scattering was employed for studying the vibrational modes in organic molecules. Ultrathin cobalt phthalocyanine films (3 nm) were deposited on Au nanoantenna arrays with specified structural parameters. The deposited organic films reveal the enhancement of both Raman scattering and IR absorption vibrational modes. To extend the possibility of implementing surface-enhanced infrared absorption (SEIRA) for biological applications, the detection and analysis of the steroid hormone cortisol was demonstrated.
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http://dx.doi.org/10.3762/bjnano.8.99DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5433160PMC
May 2017

Novel antimitotic agents related to tubuloclustin: synthesis and biological evaluation.

Mol Divers 2017 Aug 8;21(3):547-564. Epub 2017 May 8.

Institute of Biological Sciences, University of Rostock, 18059, Rostock, Germany.

Tubuloclustin [N-(7-adamant-2-yloxy-7-oxoheptanoyl)-N-deacetylcolchicine], a highly cytotoxic anti-tubulin compound is known for its ability to promote microtubule disassembly followed by the formation of tubulin clusters of unique morphology. Three series of antimitotic agents related to tubuloclustin were designed and synthesized in order to enhance the molecular diversity of "tubuloclustin-like" family of compounds. The series of compounds with modified adamantane moiety was highly potent in cytotoxic effect on human lung carcinoma A549 cells (EC50 = 6-400 nM) and was active in affecting the microtubule arrays and induction of strong tubulin clusterization. In two other sets of compounds, the colchicine moiety of tubuloclustin was replaced by podophyllotoxin or combretastatin A-4. All combretastatin A-4 derivatives displayed noticeable cytotoxic activity ([Formula: see text]) but their effect on microtubules depended on the position of the linker attachment. Podophyllotoxin derivatives were also toxic to A549 cells ([Formula: see text]) and caused both microtubule depolymerization and some tubulin clustering. The data obtained gave additional evidence that the whole panel of C7-colchicine, podophyllotoxin and combretastatin derivatives could manifest clustering effect, and the strength of this effect correlated with cytotoxic activity of the compounds.
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http://dx.doi.org/10.1007/s11030-017-9739-6DOI Listing
August 2017

Manufacturing Differences Affect Human Bone Marrow Stromal Cell Characteristics and Function: Comparison of Production Methods and Products from Multiple Centers.

Sci Rep 2017 04 27;7:46731. Epub 2017 Apr 27.

Cell Processing Section, Department of Transfusion Medicine, Clinical Center; National Institutes of Health, Bethesda, Maryland, USA.

Human bone marrow stromal cells (BMSCs, also known as bone marrow-derived mesenchymal stem cells) are manufactured using many different methods, but little is known about the spectrum of manufacturing methods used and their effects on BMSC characteristics and function. Seven centers using, and one developing, Good Manufacturing Practices (GMP) processes were surveyed as to their production methods. Among the seven centers, all used marrow aspirates as the starting material, but no two centers used the same manufacturing methods. Two to four BMSC lots from each center were compared using global gene expression. Among the twenty-four BMSC lots from the eight centers intra-center transcriptome variability was low and similar among centers. Principal component analysis and unsupervised hierarchical clustering analysis separated all the lots from five centers into five distinct clusters. BMSCs from six of the eight centers were tested for their ability to form bone and support hematopoiesis by in vivo transplantation (defining features of BMSCs). Those from all six centers tested formed bone, but the quantity formed was highly variable and BMSCs from only three centers supported hematopoiesis. These results show that differences in manufacturing resulted in variable BMSC characteristics including their ability to form bone and support hematopoiesis.
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http://dx.doi.org/10.1038/srep46731DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5406832PMC
April 2017

Localized surface plasmons in structures with linear Au nanoantennas on a SiO/Si surface.

Beilstein J Nanotechnol 2016 26;7:1519-1526. Epub 2016 Oct 26.

Semiconductor Physics, Technische Universität Chemnitz, Chemnitz, Germany.

The study of infrared absorption by linear gold nanoantennas fabricated on a Si surface with underlying SiO layers of various thicknesses allowed the penetration depth of localized surface plasmons into SiO to be determined. The value of the penetration depth derived experimentally (20 ± 10 nm) corresponds to that obtained from electromagnetic simulations (12.9-30.0 nm). Coupling between plasmonic excitations of gold nanoantennas and optical phonons in SiO leads to the appearance of new plasmon-phonon modes observed in the infrared transmission spectra the frequencies of which are well predicted by the simulations.
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http://dx.doi.org/10.3762/bjnano.7.145DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5238630PMC
October 2016

Upconversion microparticles as time-resolved luminescent probes for multiphoton microscopy: desired signal extraction from the streaking effect.

J Biomed Opt 2016 09;21(9):96002

A. M. Prokhorov General Physics Institute, Russian Academy of Sciences, Vavilov Street, 38, Moscow 119991, RussiabNational Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Kashirskoe Highway, 31, Moscow, 115409, Russia.

The great interest in upconversion nanoparticles exists due to their high efficiency under multiphoton excitation. However, when these particles are used in scanning microscopy, the upconversion luminescence causes a streaking effect due to the long lifetime. This article describes a method of upconversion microparticle luminescence lifetime determination with help of modified Lucy–Richardson deconvolution of laser scanning microscope (LSM) image obtained under near-IR excitation using nondescanned detectors. Determination of the upconversion luminescence intensity and the decay time of separate microparticles was done by intensity profile along the image fast scan axis approximation. We studied upconversion submicroparticles based on fluoride hosts doped with Yb3+-Er3+ and Yb3+-Tm3+ rare earth ion pairs, and the characteristic decay times were 0.1 to 1.5 ms. We also compared the results of LSM measurements with the photon counting method results; the spread of values was about 13% and was associated with the approximation error. Data obtained from live cells showed the possibility of distinguishing the position of upconversion submicroparticles inside and outside the cells by the difference of their lifetime. The proposed technique allows using the upconversion microparticles without shells as probes for the presence of OH? ions and CO2 molecules.
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http://dx.doi.org/10.1117/1.JBO.21.9.096002DOI Listing
September 2016

Selective Pyroelectric Detection of Millimetre Waves Using Ultra-Thin Metasurface Absorbers.

Sci Rep 2016 Feb 16;6:21079. Epub 2016 Feb 16.

Novosibirsk State University, Pirogova St. 2, Novosibirsk, 630090, Russian Federation.

Sensing infrared radiation is done inexpensively with pyroelectric detectors that generate a temporary voltage when they are heated by the incident infrared radiation. Unfortunately the performance of these detectors deteriorates for longer wavelengths, leaving the detection of, for instance, millimetre-wave radiation to expensive approaches. We propose here a simple and effective method to enhance pyroelectric detection of the millimetre-wave radiation by combining a compact commercial infrared pyro-sensor with a metasurface-enabled ultra-thin absorber, which provides spectrally- and polarization-discriminated response and is 136 times thinner than the operating wavelength. It is demonstrated that, due to the small thickness and therefore the thermal capacity of the absorber, the detector keeps the high response speed and sensitivity to millimetre waves as the original infrared pyro-sensor does against the regime of infrared detection. An in-depth electromagnetic analysis of the ultra-thin resonant absorbers along with their complex characterization by a BWO-spectroscopy technique is presented. Built upon this initial study, integrated metasurface absorber pyroelectric sensors are implemented and tested experimentally, showing high sensitivity and very fast response to millimetre-wave radiation. The proposed approach paves the way for creating highly-efficient inexpensive compact sensors for spectro-polarimetric applications in the millimetre-wave and terahertz bands.
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http://dx.doi.org/10.1038/srep21079DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4754684PMC
February 2016

Multi-modal optical imaging characterization of atherosclerotic plaques.

J Biophotonics 2016 10 25;9(10):1009-1020. Epub 2015 Nov 25.

Nizhny Novgorod State Medical Academy, 603005 Minin and Pozharsky Sq., 10/1, Nizhny Novgorod, Russia.

We combined cross-polarization optical coherence tomography (CP OCT) and non-linear microscopy based on second harmonic generation (SHG) and two-photon-excited fluorescence (2PEF) to assess collagen and elastin fibers and other vascular structures in the development of atherosclerosis, including identification of vulnerable plaques, which remains an important clinical problem and imaging application. CP OCT's ability to visualize tissue birefringence and cross-scattering adds new information about the microstructure and composition of the plaque. However its interpretation can be ambiguous, because backscattering contrast may have a similar appearance to the birefringence related fringes. Our results represent a step towards minimally invasive characterization and monitoring of different stages of atherosclerosis, including vulnerable plaques. CP OCT image of intimal thickening in the human coronary artery. The dark stripe in the cross-polarization channel (arrow) is a polarization fringe related to the phase retardation between two eigen polarization states. It is histologically located in the area of the lipid pool, however this stripe is a polarization artifact, rather than direct visualization of the lipid pool.
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http://dx.doi.org/10.1002/jbio.201500223DOI Listing
October 2016

Missense mutation in the PTEN promoter of a patient with hemifacial hyperplasia.

Bonekey Rep 2015 29;4:654. Epub 2015 Jul 29.

Childrens Hospital Los Angeles , Los Angeles, CA, USA ; Center for Craniofacial Molecular Biology, University of Southern California , Los Angeles, CA, USA ; Craniofacial and Skeletal Diseases Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health , Bethesda, MD , USA.

The cellular mechanisms involved in the asymmetric facial overgrowth syndrome, hemifacial hyperplasia (HFH), are not well understood. This study was conducted to compare primary cell cultures from hyperplastic and normal HFH bone for cellular and molecular differences. Primary cultures developed from biopsies of a patient with isolated HFH showed a twofold difference in cell size and cell number between hyperplastic and normal bone. Microarray data suggested a 40% suppression of PTEN (phosphatase-tensin homolog) transcripts. Sequencing of the PTEN gene and promoter identified novel C/G missense mutation (position -1053) in the regulatory region of the PTEN promoter. Western blots of downstream pathway components showed an increase in PKBa/Akt1 phosphorylation and TOR (target of rapamcyin) signal. Sirolimus, an inhibitor of TOR, when added to overgrowth cells reversed the cell size, cell number and total protein differences between hyperplastic and normal cells. In cases of facial overgrowth, which involve PTEN/Akt/TOR dysregulation, sirolimus could be used for limiting cell overgrowth.
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http://dx.doi.org/10.1038/bonekey.2015.21DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4520444PMC
August 2015

Human bone marrow stromal cell confluence: effects on cell characteristics and methods of assessment.

Cytotherapy 2015 Jul 14;17(7):897-911. Epub 2015 Apr 14.

Department of Transfusion Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA. Electronic address:

Background Aims: Ex vivo expansion and serial passage of human bone marrow stromal cells (BMSCs, also known as bone marrow-derived mesenchymal stem cells) is required to obtain sufficient quantities for clinical therapy. The BMSC confluence criteria used to determine passage and harvest timing vary widely, and the impact of confluence on BMSC properties remains controversial. The effects of confluence on BMSC properties were studied and confluence-associated markers were identified.

Methods: BMSC characteristics were analyzed as they grew from 50% to 100% confluence, including viability, population doubling time, apoptosis, colony formation, immunosuppression, surface marker expression, global gene expression and microRNA expression. In addition, culture supernatant protein, glucose, lactate and pH levels were analyzed.

Results: Confluence-dependent changes were detected in the expression of several cell surface markers: 39 culture supernatant proteins, 26 microRNAs and 2078 genes. Many of these surface markers, proteins, microRNAs and genes have been reported to be important in BMSC function. The pigment epithelium-derived factor/vascular endothelial growth factor ratio increased with confluence, but 80% and 100% confluent BMSCs demonstrated a similar level of immunosuppression of mixed lymphocyte reactions. In addition, changes in lactate and glucose levels correlated with BMSC density.

Conclusions: BMSC characteristics change as confluence increases. 100% confluent BMSCs may have compromised pro-angiogenesis properties but may retain their immunomodulatory properties. Supernatant lactate and glucose levels can be used to estimate confluence and ensure consistency in passage and harvest timing. Flow cytometry or microRNA expression can be used to confirm that the BMSCs have been harvested at the appropriate confluence.
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http://dx.doi.org/10.1016/j.jcyt.2015.03.607DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4461557PMC
July 2015

Discovering structural alerts for mutagenicity using stable emerging molecular patterns.

J Chem Inf Model 2015 May 7;55(5):925-40. Epub 2015 May 7.

†Normandie Université, Caen, France.

This study is dedicated to the introduction of a novel method that automatically extracts potential structural alerts from a data set of molecules. These triggering structures can be further used for knowledge discovery and classification purposes. Computation of the structural alerts results from an implementation of a sophisticated workflow that integrates a graph mining tool guided by growth rate and stability. The growth rate is a well-established measurement of contrast between classes. Moreover, the extracted patterns correspond to formal concepts; the most robust patterns, named the stable emerging patterns (SEPs), can then be identified thanks to their stability, a new notion originating from the domain of formal concept analysis. All of these elements are explained in the paper from the point of view of computation. The method was applied to a molecular data set on mutagenicity. The experimental results demonstrate its efficiency: it automatically outputs a manageable number of structural patterns that are strongly related to mutagenicity. Moreover, a part of the resulting structures corresponds to already known structural alerts. Finally, an in-depth chemical analysis relying on these structures demonstrates how the method can initiate promising processes of chemical knowledge discovery.
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http://dx.doi.org/10.1021/ci500611vDOI Listing
May 2015

Molecular profile of clonal strains of human skeletal stem/progenitor cells with different potencies.

Stem Cell Res 2015 May 25;14(3):297-306. Epub 2015 Feb 25.

Craniofacial and Skeletal Diseases Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Department of Health and Human Services, Bethesda, MD 20892, USA. Electronic address:

Bone marrow stromal cells (BMSCs, also known as bone marrow-derived mesenchymal stem cells) are fibroblastic reticular cells, a subset of which is composed of multipotent skeletal stem cells (SSCs). SSCs/BMSCs are able to recreate a bone/marrow organ in vivo. To determine differences between clonogenic multipotent SSCs and similarly clonogenic but non-multipotent BMSCs, we established single colony-derived strains (SCDSs, initiated by individual Colony Forming Unit-Fibroblasts) and determined their differentiation capacity by vivo transplantation. In this series of human SCDSs (N=24), 20.8% formed fibrous tissue (F), 66.7% formed bone (B), and 12.5% formed a bone/marrow organ, and thus were multipotent (M). RNA isolated from 12 SCDSs just prior to transplantation was analyzed by microarray. Although highly similar, there was variability from one SCDS to another, and SCDSs did not strictly segregate into the three functional groups (F, B or M) by unsupervised hierarchical clustering. We then compared 3 F-SCDSs to 3 M-SCDSs that did segregate. Genes associated with skeletogenesis, osteoblastogeneis, hematopoiesis, and extracellular matrix were over-represented in M-SCDSs compared with F-SCDSs. These results highlight the heterogeneity of SSCs/BMSCs, even between functionally similar SCDSs, but also indicate that differences can be detected that may shed light on the character of the SSC.
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http://dx.doi.org/10.1016/j.scr.2015.02.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4439347PMC
May 2015

Planar holographic metasurfaces for terahertz focusing.

Sci Rep 2015 Jan 13;5:7738. Epub 2015 Jan 13.

1] Optical and Semiconductor Devices Group, Department of Electrical and Electronic Engineering, Imperial College London, SW7 2BT, London, UK [2] Centre for Plasmonics and Metamaterials, Imperial College London, London SW7 2AZ, United Kingdom [3] Centre for Terahertz Science and Engineering, Imperial College London, London SW7 2AZ, United Kingdom.

Scientists and laymen alike have always been fascinated by the ability of lenses and mirrors to control light. Now, with the advent of metamaterials and their two-dimensional counterpart metasurfaces, such components can be miniaturized and designed with additional functionalities, holding promise for system integration. To demonstrate this potential, here ultrathin reflection metasurfaces (also called metamirrors) designed for focusing terahertz radiation into a single spot and four spaced spots are proposed and experimentally investigated at the frequency of 0.35 THz. Each metasurface is designed using a computer-generated spatial distribution of the reflection phase. The phase variation within 360 deg is achieved via a topological morphing of the metasurface pattern from metallic patches to U-shaped and split-ring resonator elements, whose spectral response is derived from full-wave electromagnetic simulations. The proposed approach demonstrates a high-performance solution for creating low-cost and lightweight beam-shaping and beam-focusing devices for the terahertz band.
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http://dx.doi.org/10.1038/srep07738DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4291574PMC
January 2015

Bone marrow skeletal stem/progenitor cell defects in dyskeratosis congenita and telomere biology disorders.

Blood 2015 Jan 12;125(5):793-802. Epub 2014 Dec 12.

Skeletal Biology Section, Craniofacial and Skeletal Diseases Branch, National Institute of Dental and Craniofacial Research.

Dyskeratosis congenita (DC) is an inherited multisystem disorder, characterized by oral leukoplakia, nail dystrophy, and abnormal skin pigmentation, as well as high rates of bone marrow (BM) failure, solid tumors, and other medical problems such as osteopenia. DC and telomere biology disorders (collectively referred to as TBD here) are caused by germline mutations in telomere biology genes leading to very short telomeres and limited proliferative potential of hematopoietic stem cells. We found that skeletal stem cells (SSCs) within the BM stromal cell population (BMSCs, also known as BM-derived mesenchymal stem cells), may contribute to the hematologic phenotype. TBD-BMSCs exhibited reduced clonogenicity, spontaneous differentiation into adipocytes and fibrotic cells, and increased senescence in vitro. Upon in vivo transplantation into mice, TBD-BMSCs failed to form bone or support hematopoiesis, unlike normal BMSCs. TERC reduction (a TBD-associated gene) in normal BMSCs by small interfering TERC-RNA (siTERC-RNA) recapitulated the TBD-BMSC phenotype by reducing proliferation and secondary colony-forming efficiency, and by accelerating senescence in vitro. Microarray profiles of control and siTERC-BMSCs showed decreased hematopoietic factors at the messenger RNA level and decreased secretion of factors at the protein level. These findings are consistent with defects in SSCs/BMSCs contributing to BM failure in TBD.
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http://dx.doi.org/10.1182/blood-2014-06-566810DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4311227PMC
January 2015

Ca2+-mediated mitochondrial reactive oxygen species metabolism augments Wnt/β-catenin pathway activation to facilitate cell differentiation.

J Biol Chem 2014 Oct 14;289(40):27937-51. Epub 2014 Aug 14.

From Electrochemical Signaling in Development and Disease, Max-Delbrück-Center for Molecular Medicine, Robert-Rössle-Strasse 10, D-13125 Berlin-Buch and

Emerging evidence suggests that reactive oxygen species (ROS) can stimulate the Wnt/β-catenin pathway in a number of cellular processes. However, potential sources of endogenous ROS have not been thoroughly explored. Here, we show that growth factor depletion in human neural progenitor cells induces ROS production in mitochondria. Elevated ROS levels augment activation of Wnt/β-catenin signaling that regulates neural differentiation. We find that growth factor depletion stimulates the release of Ca(2+) from the endoplasmic reticulum stores. Ca(2+) subsequently accumulates in the mitochondria and triggers ROS production. The inhibition of mitochondrial Ca(2+) uptake with simultaneous growth factor depletion prevents the rise in ROS metabolism. Moreover, low ROS levels block the dissociation of the Wnt effector Dishevelled from nucleoredoxin. Attenuation of the response amplitudes of pathway effectors delays the onset of the Wnt/β-catenin pathway activation and results in markedly impaired neuronal differentiation. Our findings reveal Ca(2+)-mediated ROS metabolic cues that fine-tune the efficiency of cell differentiation by modulating the extent of the Wnt/β-catenin signaling output.
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http://dx.doi.org/10.1074/jbc.M114.573519DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4183826PMC
October 2014

Generation of clinical grade human bone marrow stromal cells for use in bone regeneration.

Bone 2015 Jan 24;70:87-92. Epub 2014 Jul 24.

Department of Transfusion Medicine, Warren G. Magnuson Clinical Center, National Institutes of Health, Department of Health and Human Services, Bethesda, MD, USA; Cell Processing Section, Department of Transfusion Medicine, Warren G. Magnuson Clinical Center, National Institutes of Health, Department of Health and Human Services, Bethesda, MD, USA.

In current orthopaedic practice, there is a need to increase the ability to reconstruct large segments of bone lost due to trauma, resection of tumors and skeletal deformities, or when normal regenerative processes have failed such as in non-unions and avascular necrosis. Bone marrow stromal cells (BMSCs, also known as bone marrow-derived mesenchymal stem cells), when used in conjunction with appropriate carriers, represent a means by which to achieve bone regeneration in such cases. While much has been done at the bench and in pre-clinical studies, moving towards clinical application requires the generation of clinical grade cells. What is described herein is an FDA-approved cell manufacturing procedure for the ex vivo expansion of high quality, biologically active human BMSCs. This article is part of a Special Issue entitled Stem Cells and Bone.
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http://dx.doi.org/10.1016/j.bone.2014.07.020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4268331PMC
January 2015

Directed differentiation of human induced pluripotent stem cells toward bone and cartilage: in vitro versus in vivo assays.

Stem Cells Transl Med 2014 Jul 22;3(7):867-78. Epub 2014 May 22.

Craniofacial and Skeletal Diseases Branch, Division of Intramural Research, National Institute of Dental and Craniofacial Research, NIH, U.S. Department of Health and Human Services, Bethesda, Maryland, USA; The NIH Stem Cell Unit, Division of Intramural Research, National Institute of Neurological Disorders and Stroke, NIH, U.S. Department of Health and Human Services, Bethesda, Maryland, USA; Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, Maryland, USA

The ability to differentiate induced pluripotent stem cells (iPSCs) into committed skeletal progenitors could allow for an unlimited autologous supply of such cells for therapeutic uses; therefore, we attempted to create novel bone-forming cells from human iPSCs using lines from two distinct tissue sources and methods of differentiation that we previously devised for osteogenic differentiation of human embryonic stem cells, and as suggested by other publications. The resulting cells were assayed using in vitro methods, and the results were compared with those obtained from in vivo transplantation assays. Our results show that true bone was formed in vivo by derivatives of several iPSC lines, but that the successful cell lines and differentiation methodologies were not predicted by the results of the in vitro assays. In addition, bone was formed equally well from iPSCs originating from skin or bone marrow stromal cells (also known as bone marrow-derived mesenchymal stem cells), suggesting that the iPSCs did not retain a "memory" of their previous life. Furthermore, one of the iPSC-derived cell lines formed verifiable cartilage in vivo, which likewise was not predicted by in vitro assays.
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http://dx.doi.org/10.5966/sctm.2013-0154DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4073820PMC
July 2014
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