Browsing by Author "Carneiro, Isa"
Now showing 1 - 10 of 21
Results Per Page
Sort Options
- Deregulated expression of selected histone methylases and demethylases in prostate carcinomaPublication . Quintela Vieira, Ana Filipa; Costa-Pinheiro, Pedro; Ramalho-Carvalho, João; Menezes, Francisco Duarte; Antunes, Luis; Carneiro, Isa; Oliveira, Jorge; Henrique, Rui; Jeronimo, CarmenProstate cancer (PCa), a leading cause of cancer-related morbidity and mortality, arises through the acquisition of genetic and epigenetic alterations. Deregulation of histone methyltransferases (HMTs) or demethylases (HDMs) has been associated with PCa development and progression. However, the precise influence of altered HMTs or HDMs expression and respective histone marks in PCa onset and progression remains largely unknown. To clarify the role of HMTs and HDMs in prostate carcinogenesis, expression levels of 37 HMTs and 20 HDMs were assessed in normal prostate and PCa tissue samples by RT-qPCR. SMYD3, SUV39H2, PRMT6, KDM5A, and KDM6A were upregulated, whereas KMT2A-E (MLL1-5) and KDM4B were downregulated in PCa, compared with normal prostate tissues. Remarkably, PRMT6 was the histone modifier that best discriminated normal from tumorous tissue samples. Interestingly, EZH2 and SMYD3 expression levels significantly correlated with less differentiated and more aggressive tumors. Remarkably, SMYD3 expression levels were of independent prognostic value for the prediction of disease-specific survival of PCa patients with clinically localized disease submitted to radical prostatectomy. We concluded that expression profiling of HMTs and HDMs, especially SMYD3, might be of clinical usefulness for the assessment of PCa patients and assist in pre-therapeutic decision-making.
- Diffuse reflectance and machine learning techniques to differentiate colorectal cancer ex vivoPublication . Fernandes, Luís; Carvalho, Sónia; Carneiro, Isa; Henrique, Rui; Tuchin, Valery V.; Oliveira, Hélder P.; Oliveira, LuísIn this study, we used machine learning techniques to reconstruct the wavelength dependence of the absorption coefficient of human normal and pathological colorectal mucosa tissues. Using only diffuse reflectance spectra from the ex vivo mucosa tissues as input to algorithms, several approaches were tried before obtaining good matching between the generated absorption coefficients and the ones previously calculated for the mucosa tissues from invasive experimental spectral measurements. Considering the optimized match for the results generated with the multilayer perceptron regression method, we were able to identify differentiated accumulation of lipofuscin in the absorption coefficient spectra of both mucosa tissues as we have done before with the corresponding results calculated directly from invasive measurements. Considering the random forest regressor algorithm, the estimated absorption coefficient spectra almost matched the ones previously calculated. By subtracting the absorption of lipofuscin from these spectra, we obtained similar hemoglobin ratios at 410/550 nm: 18.9-fold/9.3-fold for the healthy mucosa and 46.6-fold/24.2-fold for the pathological mucosa, while from direct calculations, those ratios were 19.7-fold/10.1-fold for the healthy mucosa and 33.1-fold/17.3-fold for the pathological mucosa. The higher values obtained in this study indicate a higher blood content in the pathological samples used to measure the diffuse reflectance spectra. In light of such accuracy and sensibility to the presence of hidden absorbers, with a different accumulation between healthy and pathological tissues, good perspectives become available to develop minimally invasive spectroscopy methods for in vivo early detection and monitoring of colorectal cancer.The application of machine learning methods to noninvasivelike diffuse reflectance spectra allowed us to reconstruct the absorption coefficient spectra of human healthy and pathological mucosa tissues from the colorectal wall. Consequently, we were able to obtain differentiated blood and pigment content in both tissues, which can be used for the development of new noninvasive diagnostic methods for colorectal cancer.
- Enhanced Ultraviolet Spectroscopy by Optical Clearing for Biomedical ApplicationsPublication . Carneiro, Isa; Carvalho, Sonia; Henrique, Rui; Selifonov, Alexey; Oliveira, Luís; Tuchin, Valery V.In this paper, we describe the combination of ultraviolet (UV) spectroscopy with the optical clearing technique to induce new tissue windows, evaluate their efficiency, study the diffusion properties of agents and discriminate cancer. The use of highly concentrated glycerol solutions has induced high efficiency clearing effects in the UV, both in human colorectal and gingival tissues. The protein dissociation rate obtained for colorectal tissues was approximately 3 times higher in pathological than in normal mucosa and the kinetics of diffuse reflectance in the UV allowed to estimate the diffusion coefficient for water in gingival mucosa at glycerol action as (1.78 ± 0.26) × 10 -6 cm 2 /s.
- Expression of EMT-related genes CAMK2N1 and WNT5A is increased in locally invasive and metastatic prostate cancerPublication . Carneiro, Isa; Vieira, Filipa Quintela; Lobo, João; Moreira-Barbosa, Catarina; Menezes, Francisco Duarte; Martins, Ana Teresa; Oliveira, Jorge; Silva, Regina; Jerónimo, Carmen; Henrique, RuiProstate cancer (PCa) varies clinically from very indolent, not requiring therapeutic intervention, to highly aggressive, entailing radical treatment. Currently, stratification of PCa aggressiveness is mostly based on Gleason score, serum PSA and TNM stage, but outcome prediction in an individual basis is suboptimal. Thus, perfecting pre-therapeutic discrimination between indolent and aggressive PCa, avoiding overtreatment is a major challenge. Epithelial to mesenchymal transition (EMT) allows epithelial cells to acquire mesenchymal properties, constituting a critical step in tumor invasion and metastization. Thus, we hypothesized that EMT-related markers might allow for improved assessment of PCa aggressiveness. Using RealTime ready Custom Panel 384 assay, 93 EMT-related genes were assessed in normal prostate tissues (NPT, n=5), stage pT2a+b-PCa (n=5) and stage pT3b-PCa (n=5), from which CAMK2N1, CD44, KRT14, TGFβ3 and WNT5A genes emerged as the most significantly altered. Expression levels were then evaluated in a larger series (16 NPT and 94 PCa) of frozen tissues using quantitative RT-PCR. Globally, CAMK2N1, CD44 and WNT5A displayed higher expression levels at higher stages and less differentiated PCa. CAMK2N1 and WNT5A immunoexpression analysis disclosed significantly lower expression in NPT and increasing proportion of high-expression cases from pT2a+b to pT3b and metastatic PCa. Furthermore, higher CAMK2N1 and WNT5A transcript levels associated with shorter disease-free and disease-specific survival. In multivariable analysis, a trend for WNT5A expression levels to independently predict DFS was disclosed (p=0.056). Globally, our findings suggest an association between PCa aggressiveness and increased expression of CAMK2N1 and WNT5A, reflecting the acquisition of effective EMT characteristics by PCa cells.
- Fast calculation of spectral optical properties and pigment content detection in human normal and pathological kidneyPublication . Botelho, Ana R.; Silva, Hugo F.; Martins, Inês S.; Carneiro, Isa; Carvalho, Sónia D.; Henrique, Rui M.; Tuchin, Valery V.; Oliveira, Luís M.A fast calculation method was used to obtain the spectral optical properties of human normal and pathological (chromophobe renal cell carcinoma) kidney tissues. Using total transmittance, total reflectance and collimated transmittance spectra acquired from ex vivo kidney samples, the spectral optical properties of both tissues, namely the absorption, the scattering and the reduced scattering coefficients, as well as the scattering anisotropy, dispersion and light penetration depth, were calculated between 200 and 1000 nm. Analysis of the mean ab sorption coefficient spectra of the kidney tissues showed that both contain melanin and lipofuscin, and that 83 % of the melanin in the normal kidney converts into lipofuscin in the pathological kidney.
- Kinetics of Optical Properties of Colorectal Muscle During Optical ClearingPublication . Carneiro, Isa; Carvalho, Sónia; Henrique, Rui; Oliveira, Luís; Tuchin, ValeryIn this paper, we describe a simple and indirect method to evaluate the kinetics of the optical properties for biological tissues under optical clearing treatments.We use the theoretical formalism in this method to process experimental data obtained from colorectal muscle samples to evaluate and characterize the dehydration and refractive index matching mechanisms.
- Kinetics of Optical Properties of Colorectal Muscle During Optical ClearingPublication . Carneiro, Isa; Carvalho, Sonia; Henrique, Rui; Oliveira, Luís; Tuchin, Valery V.In this paper, we describe a simple and indirect method to evaluate the kinetics of the optical properties for biological tissues under optical clearing treatments. We use the theoretical formalism in this method to process experimental data obtained from colorectal muscle samples to evaluate and characterize the dehydration and refractive index matching mechanisms.
- Kinetics of optical properties of colorectal Muscle during optical clearingPublication . Carneiro, Isa; Carvalho, Sónia; Henrique, Rui; Oliveira, Luís; Tuchin, ValeryIn this paper, we describe a simple and indirect method to evaluate the kinetics of the optical properties for biological tissues under optical clearing treatments.We use the theoretical formalism in this method to process experimental data obtained from colorectal muscle samples to evaluate and characterize the dehydration and refractive index matching mechanisms.
- Kinetics of optical properties of human colorectal tissues during optical clearing: a comparative study between normal and pathological tissuesPublication . Carneiro, Isa; Carvalho, Sónia; Silva, Vânia; Henrique, Rui; Oliveira, Luís; Tuchin, Valery V.To characterize the optical clearing treatments in human colorectal tissues and possibly to differentiate between treatments of normal and pathological tissues, we have used a simple indirect method derived from Mie scattering theory to estimate the kinetics of the reduced scattering coefficient. A complementary method to estimate the kinetics of the scattering coefficient is also used so that the kinetics of the anisotropy factor and of the refractive index are also calculated. Both methods rely only on the thickness and collimated transmittance measurements made during treatment. The results indicate the expected time dependencies for the optical properties of both tissues: an increase in the refractive index and anisotropy factor and a decrease in the scattering coefficients. The similarity in the kinetics obtained for normal and pathological tissues indicates that optical clearing treatments can be applied also in pathological tissues to produce similar effects. The estimated time dependencies using experimental spectral data in the range from 400 to 1000 nm allowed us to compare the kinetics of the optical properties between different wavelengths.
- Lipofuscin-Type Pigment as a Marker of Colorectal CancerPublication . Carvalho, Sónia; Carneiro, Isa; Henrique, Rui; Tuchin, Valery; Oliveira, LuísThe study of the optical properties of biological tissues for a wide spectral range is necessary for the development and planning of noninvasive optical methods to be used in clinical practice. In this study, we propose a new method to calculate almost all optical properties of tissues as a function of wavelength directly from spectral measurements. Using this method, and with the exception of the reduced scattering coefficient, which was obtained by traditional simulation methods, all the other optical properties were calculated in a simple and fast manner for human and pathological colorectal tissues. The obtained results are in good agreement with previous published data, both in magnitude and in wavelength dependence. Since this method is based on spectral measurements and not on discrete-wavelength experimental data, the calculated optical properties contain spectral signatures that correspond to major tissue chromophores such as DNA and hemoglobin. Analysis of the absorption bands of hemoglobin in the wavelength dependence of the absorption spectra of normal and pathological colorectal mucosa allowed to identify differentiated accumulation of a pigment in these tissues. The increased content of this pigment in the pathological mucosa may be used for the future development of noninvasive diagnostic methods for colorectal cancer detection.
- «
- 1 (current)
- 2
- 3
- »