Analysis of ovarian tumor pathology by Fourier Transform Infrared Spectroscopy

<p>Abstract</p> <p>Background</p> <p>Ovarian cancer is the second most common cancer among women and the leading cause of death among gynecologic malignancies. In recent years, infrared (IR) spectroscopy has gained attention as a simple and inexpensive method for the biomedical study of several diseases. In the present study infrared spectra of normal and malignant ovarian tissues were recorded in the 650 cm^-1to 4000 cm^-1region.</p> <p>Methods</p> <p>Post surgical tissue samples were taken from the normal and tumor sections of the tissue. Fourier Transform Infrared (FTIR) data on twelve cases of ovarian cancer with different grades of malignancy from patients of different age groups were analyzed.</p> <p>Results</p> <p>Significant spectral differences between the normal and the ovarian cancerous tissues were observed. In particular changes in frequency and intensity in the spectral region of protein, nucleic acid and lipid vibrational modes were observed. It was evident that the sample-to-sample or patient-to-patient variations were small and the spectral differences between normal and diseased tissues were reproducible.</p> <p>Conclusion</p> <p>The measured spectroscopic features, which are the spectroscopic fingerprints of the tissues, provided the important differentiating information about the malignant and normal tissues. The findings of this study demonstrate the possible use of infrared spectroscopy in differentiating normal and malignant ovarian tissues.</p

Photodegradation of organic pollutants RhB dye using UV simulated sunlight on ceria based TiO2 nanomaterials for antibacterial applications

To photo-catalytically degrade RhB dye using solar irradiation, CeO2 doped TiO2 nanocomposites were synthesized hydrothermally at 700 °C for 9 hrs. All emission spectra showed a prominent band centered at 442 nm that was attributed to oxygen related defects in the CeO2-TiO2 nanocrystals. Two sharp absorption bands at 1418 cm−1 and 3323 cm−1 were attributed to the deformation and stretching vibration, and bending vibration of the OH group of water physisorbed to TiO2, respectively. The photocatalytic activities of Ce-TiO2 nanocrystals were investigated through the degradation of RhB under UV and UV+ visible light over a period of 8 hrs. After 8 hrs, the most intense absorption peak at 579 nm disappeared under the highest photocatalytic activity and 99.89% of RhB degraded under solar irradiation. Visible light-activated TiO2 could be prepared from metal-ion incorporation, reduction of TiO2, non-metal doping or sensitizing of TiO2 using dyes. Studying the antibacterial activity of Ce-TiO2 nanocrystals against E. coli revealed significant activity when 10 μg was used, suggesting that it can be used as an antibacterial agent. Its effectiveness is likely related to its strong oxidation activity and superhydrophilicity. This study also discusses the mechanism of heterogeneous photocatalysis in the presence of TiO2

Role of Minor Groove Width and Hydration Pattern on Amsacrine Interaction with DNA

Amsacrine is an anilinoacridine derivative anticancer drug, used to treat a wide variety of malignancies. In cells, amsacrine poisons topoisomerase 2 by stabilizing DNA-drug-enzyme ternary complex. Presence of amsacrine increases the steady-state concentration of these ternary complexes which in turn hampers DNA replication and results in subsequent cell death. Due to reversible binding and rapid slip-out of amsacrine from DNA duplex, structural data is not available on amsacrine-DNA complexes. In the present work, we designed five oligonucleotide duplexes, differing in their minor groove widths and hydration pattern, and examined their binding with amsacrine using attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. Complexes of amsacrine with calf thymus DNA were also evaluated for a comparison. Our results demonstrate for the first time that amsacrine is not a simple intercalator; rather mixed type of DNA binding (intercalation and minor groove) takes place between amsacrine and DNA. Further, this binding is highly sensitive towards the geometries and hydration patterns of different minor grooves present in the DNA. This study shows that ligand binding to DNA could be very sensitive to DNA base composition and DNA groove structures. Results demonstrated here could have implication for understanding cytotoxic mechanism of aminoacridine based anticancer drugs and provide directions to modify these drugs for better efficacy and few side-effects

Structural investigation of idarubicin-DNA interaction: Spectroscopic and molecular docking study

Mechanistic understanding of interaction of drugs with their target molecule is important for development of new drug therapy regimes. Idarubicin (IDR) is a potent chemotherapeutic agent used to treat variety of cancers. Structural and conformational studies associated with binding of IDR on DNA double helix were investigated through spectroscopic techniques and molecular docking studies. Interaction studies were done by preparing different molar ratios of IDR with constant DNA concentration under physiological conditions. FTIR spectroscopy, UV-vis spectroscopy, CD spectroscopy were used to analyze interaction between IDR and DNA. FUR results suggest IDR binds at major groove of DNA duplex via guanine and cytosine bases. UV-vis spectroscopy result indicates IDR gets intercalated between the DNA bases. The calculated binding constant shows that IDR is a moderate binder. Slight perturbation in the native B-conformation of DNA was observed in all IDR-DNA molar ratios examined. In silico investigation of IDR binding with DNA is in agreement with our experimental results, providing structural insight into DNA binding properties of IDR

Carboplatin interaction with calf-thymus DNA: A FTIR spectroscopic approach

Carboplatin is a chemotherapeutic drug, used for the treatment of different types of cancers, particularly solid tumors. Carboplatin, like other platinum containing drugs, exerts its cytotoxic effect through DNA binding via cross-linking. It forms interstrand and intrastrand cross-linking with DNA. Intrastrand crosslinking is dominant and believed to be conferring antitumoral efficacy of the drug. This cross-linking results in alteration of DNA winding and bending, which hampers DNA replication and transcription and finally leads to cell death. In the present work, we studied the interaction of carboplatin with calfthymus DNA in buffer solution under physiological conditions. Different concentrations of carboplatin were incubated with a constant DNA concentration to form carboplatin–DNA complexes. These complexes were studied with Fourier Transform Infrared (FTIR) spectroscopy and circular dichroism (CD)spectroscopy to understand the binding modes of carboplatin with DNA and its effect on DNA conformation.The results showed that carboplatin binds to DNA through direct interaction of platin–DNA bases (guanine, thymine, adenine and cytosine), with a small perturbation of phosphate group of DNA backbone, while DNA remains in the B-conformation. DNA aggregation was also observed at higher drug concentrations

Raman spectroscopic evaluation of DNA adducts of a platinum containing anticancer drug

Mechanistic understanding of the interaction of drugs with their target molecules is important for better understanding of their mode of action and to improve their efficacy. Carboplatin is a platinum containing anticancer drug, used to treat different type of tumors. In the present work, we applied Raman spectroscopy to study the interaction of carboplatin with DNA at molecular level using different carboplatin-DNA molar ratios. These Raman spectroscopic results provide comprehensive understanding on the carboplatin-DNA interactions and indicate that DNA cross-linked adducts formed by carboplatin are similar to cisplatin adducts. The results indicate that guanine N7 and adenine N7 are the putative sites for carboplatin interaction. It is observed that carboplatin has some affinity toward cytosine in DNA. Phosphate sugar backbone of DNA showed conformation perturbation in DNA which were easily sensible at higher concentrations of carboplatin. Most importantly, carboplatin interaction induces intermediate A- and B-DNA conformations at the cross-linking sites

Construction of spatial-coherence spectral filters using a Fourier-achromat system

Theoretical investigations made not long ago regarding the construction of spatial-coherence spectral filters (SCSFs) are rendered into experiments by designing and fabricating a Fourier-achromat experimental setup analyzed in the theoretical studies. It is shown that the phenomenon of spectral shift due to spatial coherence also known as the Wolf effect can be exploited to make special types of low-pass and band-pass spectral filters with special spectral characteristics that are not shown by the conventional filters. A Fourier-achromat is employed to construct the SCSFs. The experimental results within the experimental limitations and measurement uncertainty agree well with the theory. These filters might find applications in (i) astronomy (in the search of particular spectral lines) (ii) developing spectrum-selective optical interconnects or (iii) in cryptography

Axicon aberration leading to short-range nondiverging optical array and elliptical dark hollow beam

We propose a unique method for producing nondiverging optical array and elliptical hollow beam in a controlled manner using aberration patterns generated from oblique illumination of axicon. The optical arrays with propagation invariance property are persisted for short ranges in the focal depth, whereas diverging array with a constant number of bright spots is produced beyond bottle beam. The measured variation in the geometrical parameters of obliquely illuminated axicon setup has facilitated precise control on the dimension of optical array and shape of the elliptical hollow beam, respectively. The theoretical analysis confirms the experimental results for the generation of short-range nondiverging optical array and elliptical dark hollow beam with fine control. To the best of our knowledge, this is the first experimental approach to extend the potential of axicon beyond generation of Bessel and circular hollow beams

DNA Interaction Studies of an Anticancer Plant Alkaloid, Vincristine, Using Fourier Transform Infrared Spectroscopy

The binding of vincristine with DNA has been investigated using Fourier transform infrared spectroscopy. Various changes in the double helical structure of DNA after addition of vincristine have been examined. It is evident from Fourier transform infrared results that vincristine–DNA interaction occurs through guanine and cytosine base pairs. External binding of vincristine with phosphate backbone of the DNA is also observed. Vincristine perturbs guanine band at 1714 cm−1, cytosine band at 1488 cm−1, and the phosphate vibrations at 1225 and 1086 cm−1. The UV–visible spectra of vincristine–DNA complex show hypochromic and bathochromic shifts, indicating the intercalation of vincristine into the double helical structure of DNA. Both intercalative and external binding modes are observed for vincristine binding with DNA, with an estimated binding constant K = 1.0 × 103 M−1