Re: H Kaur Book Spectroscopy Pdf 17
Blair Capellas
An inability to discern resistant cells from bulk tumour cell population contributes to poor prognosis in Glioblastoma. Here, we compared parent and recurrent cells generated from patient derived primary cultures and cell lines to identify their unique molecular hallmarks. Although morphologically similar, parent and recurrent cells from different samples showed variable biological properties like proliferation and radiation resistance. However, total RNA-sequencing revealed transcriptional landscape unique to parent and recurrent populations. These data suggest that global molecular differences but not individual biological phenotype could differentiate parent and recurrent cells. We demonstrate that Raman Spectroscopy a label-free, non-invasive technique, yields global information about biochemical milieu of recurrent and parent cells thus, classifying them into distinct clusters based on Principal-Component-Analysis and Principal-Component-Linear-Discriminant-Analysis. Additionally, higher lipid related spectral peaks were observed in recurrent population. Importantly, Raman spectroscopic analysis could further classify an independent set of naïve primary glioblastoma tumour tissues into non-responder and responder groups. Interestingly, spectral features from the non-responder patient samples show a considerable overlap with the in-vitro generated recurrent cells suggesting their similar biological behaviour. This feasibility study necessitates analysis of a larger cohort of naïve primary glioblastoma samples to fully envisage clinical utility of Raman spectroscopy in predicting therapeutic response.
Raman spectroscopy (RS) is a vibrational spectroscopic technique based on inelastic scattering of light where the energy of photons scattered by the sample is different from the incident photon due to transfer of energy to or from the vibrational modes of molecules in the sample. This technique can be applied on live cells and is sensitive enough to detect subtle biochemical changes in the cells. Because of these reasons, Raman spectroscopy is being extensively explored in the disease diagnosis13,14,15. RS has shown promising results in the diagnosis of several cancers including cervical, lung, oral and brain tumours16,17,18,19,20,21. Most of the studies on brain tumours have focused on in vivo and ex vivo diagnosis of tumours including gliomas, followed by recent studies on surgical demarcation to determine the precise tumour margins22,23,24,25. Recent studies have also shown the utility of Raman spectroscopy and Stimulated Raman Scattering microscopy in detecting the brain regions infiltrated with tumour cells during the course of surgery and distinguishing them from the normal tissue26,27. The spectroscopic technique has further been used for evaluating the tumour response upon radiation treatment identifying treatment associated changes in tumour28,29,30. Further, RS has been explored for detecting radio-response in cervical cancers, predicting radiation response in 2RT and 5RT tissues31 and in oral cancers delving the feasibility of classifying a parental SCC cell line and its radio-resistant 50Gy and 70Gy clones32. An exploratory study in predicting recurrence of oral squamous cell carcinoma was also performed on a smaller cohort using serum Raman spectroscopy by our group33. Although such remarkable advances in Raman spectroscopy have enabled better tumour detection, Raman spectroscopy has not been explored for detection of the resistant tumour cells from parent population.
As an alternative, Raman spectroscopy- a sensitive technique based on vibrational spectroscopy known to provide holistic information about the biochemical changes inherent to the sample, was evaluated for the detection of these recurrent cells. Using Raman Spectroscopy, we were able to distinguish the recurrent cells from the parent populations of primary patient cultures and cell lines. Raman spectral features in the recurrent cells revealed significantly different biological composition seen in lipid, DNA and protein content of these cells. Variations were also seen in the spectral features of individual recurrent and patient samples in the form of minor spectral shifts and intensity-related differences. These inter-sample differences apparent between parent (or recurrent) populations from different origins were however, less significant than spectral features characteristic to parent and recurrent cells. PCA and PCA-LDA highlighted these global features specific to both parent and recurrent cells and brought about classification between parent and recurrent populations from different samples. However, variation was seen in the recurrent cells from SF268 which revealed higher DNA content and lower protein content as compared to the parent cells. This cell line also demonstrated atypical behaviour in different biological assays; this unusual biological behaviour of SF268 cell line could be the basis for the observed findings. The variability observed with respect to SF268 cell line may be reflective of the heterogeneity existing in GBM and may lead to a reduced sensitivity of any analytical method aimed at detecting recurrent cells.
Our preliminary findings indicate potential of RS in identifying recurrent cells separately from the parent cells using cellular resistance model. Since cell line based model systems do not adequately represent the heterogeneous GBM disease, we examined Raman spectra of an independent cohort of tumour samples where we found that RS could classify these tissues based on their therapy response. Nevertheless, extensive studies on larger cohort of primary GBM patients before any radio-chemotherapy intervention need to be undertaken to confirm the present findings. These studies can then set the stage for clinical translation of Raman spectroscopy for glioblastoma prognostics.
For establishment of radio-resistant populations, samples were irradiated using 60Co-γ Bhabhatron-2 radiator (ACTREC, Tata Memorial Centre). Three independent batches of recurrent population were derived from parent population of two patient samples (PS1 and PS2) and two cell lines U87MG, SF268 and were assessed using different biological assays and Raman spectroscopy.
E.K. Designed and performed experiments, acquired and analysed data, wrote the manuscript. A.S. Acquired and analysed Raman spectroscopy data, contributed to manuscript writing. A.N.A. Acquired RS data from GBM tissues. J.R. helped with the experiments. A.D., R.C. and N.G. analysed transcriptome sequencing data. A.M. acquired patient samples. M.K.C. Designed and analysed Raman spectroscopy experiments, provided input in the manuscript writing. S.D. Conceptualized the studies, designed experiments, analysed data and wrote the manuscript.
We have carried out metabolic profiling of the plasma of treatment-naïve and ART-suppressed perinatally HIV-infected children and uninfected controls using 1H nuclear magnetic resonance (NMR) spectroscopy followed by statistical analysis and annotation.
Citation: Kaur S. U, Oyeyemi BF, Shet A, Gopalan BP, D. H, Bhavesh NS, et al. (2020) Plasma metabolomic study in perinatally HIV-infected children using 1H NMR spectroscopy reveals perturbed metabolites that sustain during therapy. PLoS ONE 15(8): e0238316.
In this study, we profiled the plasma metabolome of treatment-naïve and ART-suppressed HIV-infected children, and compared them with that of uninfected controls using NMR spectroscopy. Our data suggests perturbed levels of metabolites in treatment-naïve perinatally HIV-infected children compared to uninfected controls. The ART appears to normalize majority of metabolites in perinatally HIV-infected children under treatment; some metabolites like lactate, phosphoenolpyruvic acid, oxoglutaric acid, oxaloacetic acid, myoinositol and glutamine remain elevated either due to previous exposure to HIV or ART itself.
The present study gives a brief introduction to sum-frequency generation (SFG) vibrational spectroscopy with an overview of the role of second-order nonlinear optical process. Here, we have emphasized on theoretical aspects of the SFG spectroscopy and the spectral analysis to extract the molecular structure and orientation of interfacial molecules. The interfacial structural information of various polymer materials plays an important role to determine properties like adhesion, friction, and wettability. Therefore, we have investigated the molecular structure of polydimethylsiloxane (PDMS) polymer films at the air/polymer interface by using SFG spectroscopy. The vibrational signatures of the PDMS polymer and the intensity of the SFG signal are recorded by varying the molecular weight of the PDMS polymer. The average orientation tilt angle and angular distribution width of methyl groups for each PDMS polymer are determined. The SFG results reveal the change in the intensity of SFG signals and the change in molecular tilt angle and angular distribution of methyl groups at air/PDMS film interface with the variation in the molecular weight of PDMS. The SFG spectral analysis reveals that the molecular tilt angle of the methyl group varies from 49 to 75 with respect to the surface normal and the angular distribution varies from 0 to 30 for all the PDMS polymer samples. It is interesting to find that the tilt angle of the methyl functional group of the PDMS polymer at the air/polymer interface can be controlled by varying the molecular weight of the polymer.
N2 - The present study gives a brief introduction to sum-frequency generation (SFG) vibrational spectroscopy with an overview of the role of second-order nonlinear optical process. Here, we have emphasized on theoretical aspects of the SFG spectroscopy and the spectral analysis to extract the molecular structure and orientation of interfacial molecules. The interfacial structural information of various polymer materials plays an important role to determine properties like adhesion, friction, and wettability. Therefore, we have investigated the molecular structure of polydimethylsiloxane (PDMS) polymer films at the air/polymer interface by using SFG spectroscopy. The vibrational signatures of the PDMS polymer and the intensity of the SFG signal are recorded by varying the molecular weight of the PDMS polymer. The average orientation tilt angle and angular distribution width of methyl groups for each PDMS polymer are determined. The SFG results reveal the change in the intensity of SFG signals and the change in molecular tilt angle and angular distribution of methyl groups at air/PDMS film interface with the variation in the molecular weight of PDMS. The SFG spectral analysis reveals that the molecular tilt angle of the methyl group varies from 49 to 75 with respect to the surface normal and the angular distribution varies from 0 to 30 for all the PDMS polymer samples. It is interesting to find that the tilt angle of the methyl functional group of the PDMS polymer at the air/polymer interface can be controlled by varying the molecular weight of the polymer.
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