| 1. |
- Agarwal, Nisha Rani, 1987, et al.
(author)
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Investigation of psoriasis skin tissue by label-free multi-modal imaging: a case study on a phototherapy-treated patient
- 2019
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In: Psoriasis: Targets and Therapy. - 2230-326X. ; 9, s. 43-57
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Journal article (peer-reviewed)abstract
- Background: Psoriasis is a systemic inflammatory disease characterized by epidermal proliferation in the skin. Altered lipid metabolism is considered to be a central factor in the psoriatic etiopathogenesis. Thus, it is necessary to visualize chemical specificity of the samples for better medical diagnosis and treatment. Here, we investigate its role in the development of psoriatic lesions, before and after ultraviolet phototherapy, in a case study. Methods: The distribution and morphology of different lipids and fibrous proteins in psoriatic (lesional) tissues were visualized by two complementary label-free imaging techniques: 1) non-linear microscopy (NLM), providing images of lipids/proteins throughout the skin layers at submicrometer resolution; and 2) mass spectrometry imaging (MSI), offering high chemical specificity and hence the detection of different lipid species in the epidermal and dermal regions. A conventional method of histological evaluation was performed on the tissues, with no direct comparison with NLM and MSI. Results: Psoriatic tissues had a higher lipid content, mainly in cholesterol, in both the epidermal and dermal regions, compared to healthy tissues. Moreover, the collagen and elastin fibers in the psoriatic tissues had a tendency to assemble as larger bundles, while healthy tissues showed smaller fibers more homogeneously spread. Although phototherapy significantly reduced the cholesterol content, it also increased the amounts of collagen in both lesional and non-lesional tissues. Conclusion: This study introduces NLM and MSI as two complementary techniques which are chemical specific and can be used to assess and visualize the distribution of lipids, collagen, and elastin in a non-invasive and label-free manner.
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| 2. |
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| 3. |
- Agarwal, Nisha Rani, 1987, et al.
(author)
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Nonlinear Optical Properties of Polyynes: An Experimental Prediction for Carbyne
- 2016
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In: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 120:20, s. 11131-11139
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Journal article (peer-reviewed)abstract
- We present the experimental determination of the vibrational contribution to molecular second hyperpolarizability (gamma(vib)) of very long polyynes that have been recently made available thanks to progress in chemical synthesis. Based on a simple theoretical model, the available experimental data allow estimating the asymptotic behavior of the vibrational contribution to molecular hyperpolarizability for increasing chain length.
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| 4. |
- Agarwal, Nisha Rani, 1987, et al.
(author)
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SERS detection and DFT calculation of 2-naphthalene thiol adsorbed on Ag and Au probes
- 2016
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In: Sensors and Actuators, B: Chemical. - : Elsevier BV. - 0925-4005. ; 237, s. 545-555
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Journal article (peer-reviewed)abstract
- Two different surface enhanced Raman scattering (SERS) sensors are described, tested and compared against the detection of 2-naphthalenethiol (2NPT, a volatile compound) in both solution state as well as vapor phase. The first sensor is based on an optical fiber properly modeled to induce the adhesion of colloidal Ag nanoparticles on its surface. Excitation and detection of the Raman signal is performed through the optical fiber that can be used as in situ probe for the detection of molecules adsorbed on the SERS sensitized surface. The second SERS sensor is based on nanostructured substrates consisting of Au nanoparticles produced by pulsed laser deposition in presence of a controlled Ar atmosphere. Details at the nanometer scale were observed by SEM and TEM imaging to understand the size and structure of the islands formed as a function of deposition parameters that were selected in order to maximize their SERS response. The sensitivity of the substrates to volatile species was tested by letting evaporate controlled drops of a methanol solution of 2NPT in a chamber of known volume, where the substrate was placed. After complete evaporation of the drops, this provided an in-situ environment suitable for vapor phase measurements at known concentration. SERS spectra were collected after exposing the substrates to the environment within the chamber (vapor phase measurements) or dipping them in a solution for condensed state measurements. The complete absence of the SH stretching peak in the SERS spectra proves the covalent bonding of 2NPT to the metal substrates via the sulfur atom. DFT calculations, including metal-sulfur interaction, provide a good description of the observed SERS spectra. The reported data allow concluding that our SERS substrates are suitable for detection of volatile compounds.
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| 5. |
- Blockhuys, Stephanie, 1983, et al.
(author)
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Second harmonic generation for collagen I characterization in rectal cancer patients with and without preoperative radiotherapy
- 2017
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In: Journal of Biomedical Optics. - : SPIE-Intl Soc Optical Eng. - 1560-2281 .- 1083-3668. ; 22:10
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Journal article (peer-reviewed)abstract
- Rectal cancer is treated with preoperative radiotherapy (RT) to downstage the tumor, reduce local recurrence, and improve patient survival. Still, the treatment outcome varies significantly and new biomarkers are desired. Collagen I (Col-I) is a potential biomarker, which can be visualized label-free by second harmonic generation (SHG). Here, we used SHG to identify Col-I changes induced by RT in surgical tissue, with the aim to evaluate the clinical significance of RT-induced Col-I changes. First, we established a procedure for quantitative evaluation of Col-I by SHG in CDX2-stained tissue sections. Next, we evaluated Col-I properties in material from 31 non-RT and 29 RT rectal cancer patients. We discovered that the Col-I intensity and anisotropy were higher in the tumor invasive margin than in the inner tumor and normal mucosa, and RT increased and decreased the intensity in inner tumor and normal mucosa, respectively. Furthermore, higher Col-I intensity in the inner tumor was related to increased distant recurrence in the non-RT group but to longer survival in the RT group. In conclusion, we present a new application of SHG for quantitative analysis of Col-I in surgical material, and the first data suggest Col-I intensity as a putative prognostic biomarker in rectal cancer.
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| 6. |
- Blockhuys, Stephanie, 1983, et al.
(author)
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X-radiation enhances the collagen type I strap formation and migration potentials of colon cancer cells
- 2016
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In: Oncotarget. - : Impact Journals, LLC. - 1949-2553. ; 7:44, s. 71390-71399
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Journal article (peer-reviewed)abstract
- Rectal cancer treatment still fails with local and distant relapses of the disease. It is hypothesized that radiotherapy could stimulate cancer cell dissemination and metastasis. In this study, we evaluated the effect of X-radiation on collagen type I strap formation potential, i.e. matrix remodeling associated with mesenchymal cell migration, and behaviors of SW480, SW620, HCT116 p53(+/+) and HCT116 p53(-/-) colon cancer cells. We determined a radiation-induced increase in collagen type I strap formation and migration potentials of SW480 and HCT116 p53(+/+). Further studies with HCT116 p53(+/+), indicated that after X-radiation strap forming cells have an increased motility. More, we detected a decrease in adhesion potential and mature integrin beta 1 expression, but no change in non-muscle myosin II expression for HCT116 p53(+/+) after X-radiation. Integrin beta 1 neutralization resulted in a decreased cell adhesion and collagen type I strap formation in both sham and X-radiated conditions. Our study indicates collagen type I strap formation as a potential mechanism of colon cancer cells with increased migration potential after X-radiation, and suggests that other molecules than integrin beta 1 and non-muscle myosin II are responsible for the radiation-induced collagen type I strap formation potential of colon cancer cells. This work encourages further molecular investigation of radiation-induced migration to improve rectal cancer treatment outcome.
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| 7. |
- Chen, Xin, 1980, et al.
(author)
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Interplay of Energetics and ER Stress Exacerbates Alzheimer's Amyloid-beta (A beta) Toxicity in Yeast
- 2017
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In: Frontiers in Molecular Neuroscience. - : Frontiers Media SA. - 1662-5099. ; 10
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Journal article (peer-reviewed)abstract
- Alzheimer's disease (AD) is a progressive neurodegeneration. Oligomers of amyloid-beta peptides (A beta) are thought to play a pivotal role in AD pathogenesis, yet the mechanisms involved remain unclear. Two major isoforms of A beta associated with AD are A beta 40 and A beta 42, the latter being more toxic and prone to form oligomers. Here, we took a systems biology approach to study two humanized yeast AD models which expressed either A beta 40 or A beta 42 in bioreactor cultures. Strict control of oxygen availability and culture pH, strongly affected chronological lifespan and reduced variations during cell growth. Reduced growth rates and biomass yields were observed upon A beta 42 expression, indicating a redirection of energy from growth to maintenance. Quantitative physiology analyses furthermore revealed reduced mitochondria' functionality and ATP generation in A beta 42 expressing cells, which matched with observed aberrant mitochondria' structures. Genome-wide expression level analysis showed that A beta 42 expression triggered strong ER stress and unfolded protein responses. Equivalent expression of A beta 40, however, induced only mild ER stress, which resulted in hardly affected physiology. Using AD yeast models in well controlled cultures strengthened our understanding on how cells translate different A beta toxicity signals into particular cell fate programs, and further enhance their potential as a discovery platform to identify possible therapies.
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