Clinical Spectroscopy最新文献

In this contribution, data will be presented that suggest that certain cancer markers or their surrogates can be detected by infrared spectral imaging methodology. In particular, the co-localization of certain regions in spectral images with PD-L1-postive immunohistochemical response suggests that either the PD-L1 protein or a surrogate associated with its presence are detectable. In the case of Her2/neu, an analysis of mean spectral signatures of over forty thousand individual spectra revealed small, but statistically significant spectral differences between cancer marker positive and negative tissues in spectral regions associated with protein phosphorylation.

The development of a label-free, non-destructive and safe analytical method such as Raman spectroscopy for assessing cartilage degradation is highly desirable. Compared to non-optical imaging modalities, Raman mapping offers a more sensitive means of directly assessing the chemical composition of cartilage in three-dimensional space and the potential to monitor cartilage degeneration to inform intervention and treatment strategies. Herein, we report the application of Raman spectroscopic methods ex vivo and at arthroscopy to identify molecular alterations in cartilage specimens containing minor focal lesions characteristic of the early disease phase. Our initial ex vivo analysis, obtained by single-point Raman spectroscopy of cartilage samples, supports previous findings based on S-O stretching vibration bands associated with sulphated glycosaminoglycans (sGAGs). We extended the analyses to the high-wavenumber region where we observed that vibrational bands assigned to C-H and O-H stretching modes discriminated early cartilage alterations from healthy cartilage samples. Furthermore, we performed a proof-of-concept in-clinic study using a custom-built optical probe to acquire Raman spectral measurements for the first time in patients undergoing arthroscopy of knee joints. Spectra were obtained with adequate signal-to-noise ratios that similarly discriminated between lesion and adjacent cartilage sites and identified reductions in sGAGs in apparently healthy cartilage. Building on this, we present initial results from Raman mapping to spatially resolve the molecular constituents of cartilage through its depth and across a lesion. Mapping revealed a non-uniform and reduced sGAG distribution within the lesion and peripheral cartilage that was otherwise visually normal, similar to the in-clinic observations, showing that the degradative influence of the lesion extended beyond its border. This was accompanied by a decreased fluorescence signal intensity, which suggests that fluorescence may provide valuable information as an adjunct to the Raman signal in discriminating normal and degenerating cartilage. This work demonstrates the value of Raman mapping over single-point Raman measurements for the analysis of the anisotropy of articular cartilage and highlights the potential of the technology for in vivo articular joint arthroscopy applications.

Pancreatic cancer is one of the most aggressive and lethal malignant neoplasms in the world and 5-year survival rate still remains below 10%. Although, there are many reasons for that, one definitely is the lack of early and unique diagnostic tools for pancreatic cancer screening, which somehow correlates with no sufficient knowledge about cancer’s molecular nature. This article aims to prove the concept that an application of molecular spectroscopic methods including FTIR hyperspectral imaging and Raman hyperspectral mapping, combined with proper tissue pre-processing and analytical algorithms, allows differentiating benign and malignant pancreatic glands with good precision.

The erythrocytes obtained from patients diagnosed with Plasmodium falciparum or Plasmodium vivax infection (two groups of five patients each) and treated in the Department of Infectious Diseases, University Hospital in Kraków, were measured using the Raman spectroscopy method (1–2 cells of each patient) and then compared with the results from these patients during their convalescence. Principal Component Analysis (PCA) was used to determine the variance between the Raman spectra. Changes in the heme structure were observed by the v₄ oxidation state marker and by other heme and hemozoin marker bands, as well as protein side chains marker bands. The recognized Raman bands allow to differentiate changes taking place in the red blood cells during the development of Plasmodium falciparum from Plasmodium vivax. The 1385 cm⁻¹ Asp band along with the 1587 cm⁻¹ Gln vibrations at the beginning of hospitalization specify the invasion of P. falciparum that occurs with the basigin receptor which requires respective protein glycosylation. The 1361 cm⁻¹ and 1544 cm⁻¹ Trp bands indicate the invasion stage of the P. vivax parasite, and the formation of the ligand-receptor complex. To our knowledge, this is the first Raman spectroscopic observation that we can distinguish Plasmodium species.

Infrared spectral pathology has gained significant attention in the last few years, since it has been demonstrated to be able to readily identify cancerous tissue in biopsy samples. The Infrared technique, however, normally requires tissue sections to be mounted on infrared transparent slides. Unfortunately, these slides are both expensive and particularly frangible. In addition, mounting samples on specialist slides is an additional step in the sample preparation workflow, which ideally should be avoided. Applying infrared imaging directly to the H&E stained tissue on the glass slides that are normally used by pathologists, could help the infrared imaging technique be incorporated into current cancer diagnosis work flow and lower the total cost of detection. The disadvantage of using glass slides is that the spectral range available is restricted to just the high wavenumber region (2500–3600 cm⁻¹). In this work a study has been conducted on 120 breast tissues biopsy cores from different patients, to demonstrate that with the limited spectral information, breast cancer can be identified from the H&E glass slides. A four-class histological Adboost classification model has been constructed. Optimisation of the classification threshold was carried out to reduce the number of false negatives. Using a threshold of 0.1 the cancerous cores could be detected with an accuracy of 95.8 %. This was incorporated into a simple traffic light system that could be used as a prescreening tool. This work, demonstrating the use of infrared spectral pathology on standard pathology samples slide, thus goes some way to overcome one of the barriers to successful translation of the infrared technique into the clinic.

Analysis of bodily fluids using vibrational spectroscopy has attracted increasing attention in recent years. In particular, infrared spectroscopic screening of blood products, particularly blood serum, for disease diagnostics has been advanced considerably, attracting commercial interests. However, analyses requiring quantification of endogenous constituents or exogenous agents in blood are less well advanced. Recent advances towards this end are reviewed, focussing on infrared and Raman spectroscopic analyses of human blood serum. The importance of spectroscopic analysis in the native aqueous environment is highlighted, and the relative merits of infrared absorption versus Raman spectroscopy are considered, in this context. It is argued that Raman spectroscopic analysis is more suitable to quantitative analysis in liquid samples, and superior performance for quantification of high and low molecular weight components, is demonstrated. Applications for quantitation of viral loads, and therapeutic drug monitoring are also discussed.

The development of a new fast, portable and reagent-free diagnostic technique for hepatitis B (HBV) and hepatitis C (HCV) viruses would be an enormous benefit to society. Here, we evalulate the ability of Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) spectroscopy combined with multivariate data analysis to classify human serum samples based on the presence of HBV and HCV infection. Sera samples were prepared using three different methodologies: i) Sera depsoited onto glass cover slips, airdried and placed onto the ATR crystal. ii) Whole serum dried directly onto the ATR crystal. iii) Serum separated into high and low molecular weight compounds using a filtration approach and the high molecular weight fraction placed directly onto the ATR-FTIR diamond window and dried. For methodology i) the Partial Least Squares Discriminate Analysis (PLS-DA) calibration set included 313 (70 %) samples and the validation set 93 (30 %) samples. For HBV vs control the sensitivity and specificity was found to be 69.4 % and 73.7 % (10 latent variables (LV)), respectively. For HCV vs control the sensitivity and specificity was 51.3 % and 90.9 % (LV 11), respectively. In the second set of experiments the serum samples were dried directly onto the ATR diamond. PLS-DA models were constructed using 144 (70 %) samples for the calibration set and tested using an independent test set containing 62 (30 %) samples. For HBV versus control the sensitivity and the specificity was 84.4 % and 93.1 %, respectively (LV 8). For HCV versus control the sensitivity and specificity was 80.0 % and 97.2 %, respectively (LV 9). For HBV versus HCV the sensitivity and the specificity was 77.4 % and 83.3 %, respectively (LV 5). To increase the sensitivity and specificity serum sample was fractionated into high and low molecular weight components. In PLS-DA cross validated model (LV 8) the sensitivity and specificity was 87.5 % and 94.9 %, respectively for HBV vs control (high molecular concentrate). The PLS-DA cross-validated model (LV 8) for HCV vs control high molecular fraction produced a sensitivity and specificity of 81.6 % and 89.6 %, respectively. No linear correlation was observed for sera samples spiked with known viral loads using Partial Least Squares Regression (PLS-R) modelling.

Spectra of positive serum (HBV and HCV) showed a strong band observed at 1631 cm⁻¹, which was absent in the spectra of controls and assigned to the β-pleated sheet protein marker of immunoglobulin (Ig). A band at 1093 cm⁻¹, observed in spectra of HBV infected sera, was assigned to CC and COmodes of polysaccharide N-glycan from hepatitis B surface antigen (HBsAg). The assignment was confirmed by atomic force microsocpy infrared (AFM-IR) spectroscopy of the isolated protein. This band represents a unique marker for HBV infection. In summary, ATR-FTIR spectroscopy is a powerful tool to study blood composition and identify potential disease marke