Vibrational spectroscopic methods are widely used in the molecular diagnostics of carcinogenesis. Collagen, a component of connective tissue, plays a special role as a biochemical marker of pathological changes in tissues. The vibrational bands of collagens are very promising to distinguish between normal colon tissue, benign and malignant colon polyps. Differences in these bands indicate changes in the amount, structure, conformation and the ratio between the individual structural forms (subtypes) of this protein. The screening of specific collagen markers of colorectal carcinogenesis was carried out based on the FTIR and Raman (λex 785 nm) spectra of colon tissue samples and purified human collagens. It was found that individual types of human collagens showed significant differences in their vibrational spectra, and specific spectral markers were found for them. These collagen bands were assigned to specific vibrations in the polypeptide backbone, amino acid side chains and carbohydrate moieties. The corresponding spectral regions for colon tissues and colon polyps were investigated for the contribution of collagen vibrations. Mentioned spectral differences in collagen spectroscopic markers could be of interest for early ex vivo diagnosis of colorectal carcinoma if combine vibrational spectroscopy and colonoscopy.
- MeSH
- kolagen MeSH
- kolonoskopie * metody MeSH
- kolorektální nádory * diagnóza MeSH
- lidé MeSH
- Ramanova spektroskopie metody MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Colorectal cancer is one of the most common and often fatal cancers in humans, but it has the highest chance of a cure if detected at an early precancerous stage. Carcinogenesis in the colon begins as an uncontrolled growth forming polyps. Some of these polyps can finally be converted to colon cancer. Early diagnosis of adenomatous polyps is the main approach for screening and preventing colorectal cancer, and vibration spectroscopy can be used for this purpose. This work is focused on evaluating FTIR and Raman spectroscopy as a tool in the ex vivo analysis of colorectal polyps, which could be important for the early diagnosis of colorectal carcinoma. Multivariate analyses (PCA and LDA) were used to assist the spectroscopic discrimination of normal colon tissue, as well as benign and malignant colon polyps. The spectra demonstrated evident differences in the characteristic bands of the main tissue constituents, i.e., proteins, nucleic acids, lipids, polysaccharides, etc. Suitable models for discriminating the three mentioned diagnostic groups were proposed based on multivariate analyses of the spectroscopic data. LDA classification was especially successful in the case of a combined set of 55 variables from the FTIR, FT Raman and dispersion Raman spectra. This model can be proposed for ex vivo colorectal cancer diagnostics in combination with the colonoscopic extraction of colon polyps for further testing. This pilot study is a precursor for the further evaluation of the diagnostic potential for the simultaneous in vivo application of colonoscopic Raman probes.
- Publikační typ
- časopisecké články MeSH
Prevalence of tumors and the search for effective diagnostic approach is a very topical issue worldwide. According to the Czech National Cancer Registry (CNCR), colon and lung cancers are the most common types of cancer in the Czech Republic. This review is focused on brief literal survey of known, widely used and newly evolving methods suitable for early diagnosis of the mentioned cancer diseases.
- MeSH
- biologické markery MeSH
- časná detekce nádoru MeSH
- endoskopie MeSH
- imunologické testy MeSH
- interpretace statistických dat MeSH
- kolorektální nádory * diagnostické zobrazování diagnóza prevence a kontrola MeSH
- lidé MeSH
- mikroskopie metody MeSH
- nádory plic * diagnostické zobrazování diagnóza prevence a kontrola MeSH
- plošný screening klasifikace MeSH
- Ramanova spektroskopie * metody MeSH
- spektroskopie infračervená s Fourierovou transformací * klasifikace metody přístrojové vybavení MeSH
- statistika jako téma klasifikace MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
- přehledy MeSH
Raman optical activity (ROA) is inherently sensitive to the secondary structure of biomolecules, which makes it a method of interest for finding new approaches to clinical applications based on blood plasma analysis, for instance the diagnostics of several protein-misfolding diseases. Unfortunately, real blood plasma exhibits strong background fluorescence when excited at 532 nm; hence, measuring the ROA spectra appears to be impossible. Therefore, we established a suitable method using a combination of kinetic quenchers, filtering, photobleaching, and a mathematical correction of residual fluorescence. Our method reduced the background fluorescence approximately by 90%, which allowed speedup for each measurement by an average of 50%. In addition, the signal-to-noise ratio was significantly increased, while the baseline distortion remained low. We assume that our method is suitable for the investigation of human blood plasma by ROA and may lead to the development of a new tool for clinical diagnostics.
- MeSH
- fluorescence MeSH
- krevní plazma chemie MeSH
- lidé MeSH
- optická otáčivost MeSH
- Ramanova spektroskopie přístrojové vybavení metody MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Colorectal cancer is one of the most abundant causes of cancer deaths in the world. At an early stage, the established clinical procedures have low reliability and sensitivity. Therefore, we tested a novel approach based on chiroptical methods such as electronic circular dichroism (ECD) and Raman optical activity (ROA). These methods are suitable for detecting slight changes in the 3D structure of chiral biomolecules, some of which may be caused by pathological processes occurring during cancer growth. Fifty-five blood plasma samples were analyzed using the combination of ECD and ROA supplemented by conventional Raman and FT-IR spectroscopy. All obtained spectra were evaluated together by linear discriminant analysis. The accuracy of sample discrimination reached 100% and the subsequent leave-one-out cross-validation resulted in 93% sensitivity and 81% specificity. The achieved results indicate that chiroptical methods supplemented by Raman and FT-IR spectroscopy might be new supporting and minimally invasive tools in the clinical diagnosis of colon cancer.
- MeSH
- cirkulární dichroismus * MeSH
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- nádory tračníku krev diagnóza MeSH
- Ramanova spektroskopie * MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- studie případů a kontrol MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Chiroptical methods are widely used in structural and conformational analyses of biopolymers. The application of these methods to investigations of biofluids would provide new avenues for the molecular diagnosis of protein-misfolding diseases. In this work, samples of human blood plasma and hen egg white were analyzed using a combination of conventional and chiroptical methods: ultraviolet absorption/electronic circular dichroism (UV/ECD), Fourier transform infrared absorption/vibrational circular dichroism (FTIR/VCD), and Raman scattering/Raman optical activity (Raman/ROA). For comparison, the main components of these substances--human serum albumin (HSA) and ovalbumin (Ova)--were also analyzed by these methods. The ultraviolet region of the ECD spectrum was analyzed using the CDNN CD software package to evaluate the secondary structures of the proteins. The UV/ECD, FTIR/VCD, and Raman/ROA spectra of the substances were quite similar to those of the corresponding major proteins, while some differences were also detected and explained. The conclusions drawn from the FTIR/VCD and Raman/ROA data were in good agreement with the secondary structures calculated from ECD. The results obtained in this work demonstrate that the chiroptical methods used here can be applied to analyze not only pure protein solutions but also more complex systems, such as biological fluids.
- MeSH
- aminokyseliny chemie MeSH
- cirkulární dichroismus metody MeSH
- krevní proteiny analýza chemie MeSH
- lidé MeSH
- Ramanova spektroskopie metody MeSH
- sekundární struktura proteinů * MeSH
- sérový albumin analýza MeSH
- software MeSH
- spektrofotometrie ultrafialová metody MeSH
- spektroskopie infračervená s Fourierovou transformací metody MeSH
- stereoizomerie MeSH
- vaječný bílek analýza MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Polysaccharide films containing chitosan, methylcellulose, and a mixture of these polysaccharides in various ratios were prepared and modified with meso-tetrakis(4-sulfonatophenyl)porphyrin in an aqueous medium at pH 7. The modified films were compared with the initial films using spectroscopic methods and microscopic imaging. Electronic (UV-vis absorption, electronic circular dichroism (ECD)) and vibrational (FTIR and Raman) spectra showed that the porphyrin macrocycles had a strong affinity toward chitosan and did not interact with the methylcellulose. The total porphyrin uptake depended on the chitosan: methylcellulose ratio and pure methylcellulose films did not retain porphyrin macrocycles. ECD measurements detected the presence of optically active porphyrin species bound to the films. SEM and AFM images confirmed that the porphyrin macrocycles caused structural changes on the film surface and within the film layer.
- MeSH
- absorpce MeSH
- biokompatibilní materiály chemická syntéza MeSH
- chitosan chemie MeSH
- cirkulární dichroismus MeSH
- koncentrace vodíkových iontů MeSH
- lékové transportní systémy metody MeSH
- methylcelulosa chemie MeSH
- mikroskopie elektronová rastrovací MeSH
- molekulární struktura MeSH
- porfyriny chemie MeSH
- Ramanova spektroskopie MeSH
- spektroskopie infračervená s Fourierovou transformací MeSH
- voda MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
