optical constants
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OBJECTIVE: In this experimental study, we aimed to determine whether platelet-rich plasma (PRP) is a suitable preservative for dermo-epidermal grafts. An additional objective was to investigate how long grafts can be stored without biological degradation. METHODS: We compared pig skin graft preservation using PRP versus saline solution and crystalloid Custodiol®, which is used for hypothermic preservation of organs for transplantation. Grafts (10 × 10 mm) were placed on gauze impregnated with one of the tested solutions, and stored for 3, 7, 11, and 15 days at a constant temperature of 4°C. We evaluated a total of 240 pig skin samples: 120 by histopathology and 120 by fluorescence optical microscopy. RESULTS: Overall, Custodiol® solution appeared to be the best medium for preservation of dermo-epidermal grafts, with beneficial properties manifested on days 7 and 11. Although we expected PRP to be a better preservative than saline, this was not confirmed by our results, as we found no significant difference between these two media. In fact, by day 3, the histopathological results were better with standard saline solution than with PRP. On day 15, with each tested solution, some samples showed histological changes that are incompatible with graft viability. CONCLUSION: Overall, Custodiol® appears to be the best medium for dermo-epidermal graft preservation. Moreover, the present findings suggest a maximum graft storage time of 11 days in all of the tested solutions. We do not recommend using grafts stored for 15 days, due to isolated signs of graft biodegradation with all solutions.
- Publikační typ
- časopisecké články MeSH
Current molecular diagnostics of prostate cancer relies on detection of elevated levels of PSA protein in serum, but its specificity has been questioned due to its higher levels also in non-malignant prostate diseases. A long non-coding RNA biomarker, PCA3, demonstrated excellent specificity for prostate cancer, and thus has become an interesting alternative to PSA monitoring. Its detection utilizes mostly reverse transcription PCR with optical detection, making the protocol longer and more expensive. To avoid PCR, we have developed an electrochemical assay coupled with LAMP, an isothermal amplification technique showing high sensitivities at constant temperatures and shorter reaction times. We amplified PCA3 RNA as well as PSA mRNA (serving as a control), hybridized LAMP products on magnetic beads and measured them with chronoamperometry at carbon electrode chips. We show good sensitivity and specificity for both biomarkers in prostate cancer cell lines, and successful detection of PCA3 in clinical samples, i.e., urine samples from 11 prostate cancer patients and 7 healthy controls, where we obtained excellent correlation with clinical data. This is to our knowledge a first such attempt to apply electrochemistry to determine two RNA biomarkers directly in urine samples of prostate cancer patients in a minimally invasive diagnostics format.
- MeSH
- antigeny nádorové * genetika MeSH
- biologické markery MeSH
- lidé MeSH
- nádorové biomarkery genetika MeSH
- nádory prostaty * diagnóza genetika MeSH
- prostatický specifický antigen MeSH
- RNA MeSH
- senzitivita a specificita MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
INTRODUCTION: This study aimed to evaluate changes in facial size and shape in children and their relationship to the changes in height and weight. METHODS: One hundred and thirteen healthy children aged between 6 and 13 years were followed annually for 2 consecutive years. The facial morphology was captured in 12-month intervals (from T1 to T2 and from T2 to T3) using a 3-dimensional stereophotogrammetric optical scanner; the body height and weight were recorded simultaneously. The changes in facial size and shape were analyzed with geometric morphometrics. Multiple regression mixed-effects models were exploited for evaluation of the association between the changes of facial size or shape and age at the beginning of the observation, gender, and change of height and weight. RESULTS: The centroid size (reflecting facial size) increased from T1 to T2 and T2 to T3 in boys and girls. In contrast, the facial shape did not change during both 12-month observation periods (T1 to T2 and T2 to T3) either in boys or girls. Of 2 multiple regression mixed-effects models, only the model with the change of natural logarithm of centroid size as a dependent variable was statistically significant (P <0.001; adjusted r2 = 0.29). It showed that height and weight changes were associated with a change of the facial size (with weight change having a greater effect than height change: adjusted r2 = 0.25 for weight change and adjusted r2 = 0.106 for height change). CONCLUSIONS: Most changes in the facial morphology observed in our cohort were associated with increasing facial size. In contrast, the shape of the face remained relatively constant. Body height and weight gains were associated with the change of the facial size only. However, only 29% of the variation in facial size was explained by height or weight changes during growth.
- MeSH
- dítě MeSH
- fotogrammetrie MeSH
- hmotnostní přírůstek MeSH
- lidé MeSH
- mladiství MeSH
- následné studie MeSH
- obličej * anatomie a histologie diagnostické zobrazování MeSH
- tělesná výška * MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- mladiství MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Cíl: Cílem studie bylo analyzovat předozadní poměr optické mohutnosti rohovky (AP poměr), provést komparaci výsledných hodnot s hodnotami teoretických modelů oka a definovat vliv použití individuální hodnoty poměru na aproximaci celkové mohutnosti rohovky. Materiál a metody: Do souboru bylo zařazeno celkem 406 očí. Každý pacient podstoupil vyšetření na OCT (RTVue XR) s TCP módem, dle kterého byl stanoven AP poměr rohovky, dále byly stanoveny biometrické parametry oka (Lenstar LS900). Vzájemný vztah biometrických parametrů oka a individuální hodnoty AP poměru byl hodnocen pomocí Pearsonova korelačního koeficientu. V analýze byly výsledky AP poměru komparovány s vybranými schématickými modely oka. Za využití Gaussových vztahů byla dosazením hodnoty AP poměru realizována teoretická kalkulace celkové optické mohutnosti rohovky (KG), která byla komparována s reálně naměřenou celkovou optickou mohutností (TCP). Výsledky: Průměrná hodnota z individuálně stanovených AP poměrů byla rovna 1,17 ±0,02. Nejčetněji zastoupeným intervalem (33,74 %) byl 1,17–1,18 hodnoty AP poměru, přičemž naprostá většina očí (79,56 %) byla v rozsahu 1,15–1,20. Teoretické hodnoty celkové optické mohutnosti rohovky se statisticky významně lišily (p < 0,05) od TCP (kromě modelu oka dle Liou-Brennana, kdy p = 0,06). Nejnižší průměrná diference hodnot byla nalezena pro schématický model dle Navarra. Závislost hodnot měřeného AP poměru a biometrických parametrů dosáhla střední negativní korelace (r = -0,50 pro p < 0,05) s parametrem zakřivení zadní plochy rohovky (Rp) a dále slabá negativní korelace s průměrem limbu WtW (r = -0,26 pro p < 0,05) a slabá pozitivní s centrální tloušťkou rohovky CCT (r = 0,17 pro p < 0,05). Závěr: Předpoklad konstantní hodnoty AP poměru dle vybraných schématických modelů oka se statisticky významně liší od reálně naměřených hodnot a byla pro něj definována pouze negativní slabá korelace s velikostí průměru limbu. Použitím výsledné průměrné hodnoty stanoveného AP poměru (1,17 ±0,02) bylo docíleno nižší diference reálné a kalkulované celkové optické mohutnosti rohovky.
Aims: The aim of the study was to analyse the values of the anteroposterior corneal optical power ratio (AP ratio), to compare the resulting values with those of theoretical models of the eye, and to define the effect of using an individual ratio value on the approximation of the total corneal power. Material and Methods: A total of 406 eyes were included. Each patient underwent an OCT (RTVue XR) examination, according to which the AP ratio of the cornea was determined, as well as the biometric parameters of the eye (Lenstar LS900). The correlation between the biometric parameters of the eye and the individual AP ratio values was evaluated using Pearson’s correlation coefficient. In the analysis, the AP ratio results were compared with selected schematic models of the eye. Using Gaussian equations, a theoretical calculation of the total corneal optical power (KG) was performed, by fitting the AP ratio value and comparing it with the actually measured total corneal power (TCP). Results: The mean value of the individually determined AP ratio was 1.17 ±0.02. The most frequently represented interval (33.74 %) was 1.17 to 1.18 AP ratio values, with the vast majority of eyes (79.56 %) in the range of 1.15 to 1.20. Individual values of total corneal optical power were statistically significantly different (p < 0.05) from the theoretical values of TCP (except in the Liu-Brennan eye model, where p = 0.06). The lowest mean difference of values was found for the Navarro schematic model. The dependence of the measured AP ratio values and biometric parameters reached a moderate negative correlation (r = -0.50 for p < 0.05) with the parameter corneal posterior surface curvature (Rp), as well as a weak negative correlation with limbal diameter WtW (r = -0.26 for p < 0.05) and a weak positive correlation with central corneal thickness CCT (r = 0.17 for p < 0.05). Conclusion: The assumption of a constant value of the AP ratio according to the selected schematic models of the eye is statistically significantly different from the actual measured values and was defined to have only a negative weak correlation with the size of the limbus diameter. Using the resulting average value of the determined AP ratio (1.17 ±0.02), a lower difference between real and calculated total corneal optical power was achieved.
Electrochemical (EC) detection of DNA biomarkers represents an interesting tool in molecular oncology due to its sensitivity, simplicity, low cost or rapid times of measurement. However, majority of EC assays, same as most optical-based techniques, require preceding DNA extraction step to remove other cellular components, making these assays more laborious and time-consuming. One option to circumvent this is to use LAMP (loop-mediated amplification), an isothermal amplification technique that can amplify DNA directly in crude lysates in a short time at a constant temperature. Here, we coupled the LAMP reaction with EC readout to detect DNA from the two most common oncogenic human papillomavirus (HPV) types that cause cervical cancer in women, i.e. HPV 16 and HPV 18, directly in crude lysates without a need for DNA extraction step. We show that in crude lysates, the LAMP reaction was superior to PCR, with very good selectivity on a panel of cancer cell lines and with high sensitivity, enabling detection of HPV DNA from as few as 10 cells. As a proof of principle, we applied the assay to nineteen clinical samples both from uninfected women and from women suffering from cervical precancerous lesions caused by HPV 16 or HPV 18 genotypes. Clinical samples were simply boiled for 5 min in homogenization buffer without DNA extraction step, and amplified with LAMP. We obtained excellent concordance of our assay with PCR, reaching 100% sensitivity for both genotypes, 81.82% specificity for HPV 16 and 94.12% specificity for HPV 18. Proposed assay could be a straightforward, simple, rapid and sensitive alternative for early diagnostics of precancerous cervical lesions.
There is a constant need for the development of easy-to-operate systems for the rapid and unambiguous identification of bacterial pathogens in drinking water without the requirement for time-consuming culture processes. In this study, we present a disposable and low-cost lab-on-a-chip device utilizing a nanoporous membrane, which connects two stacked perpendicular microfluidic channels. Whereas one of the channels supplies the sample, the second one attracts it by potential-driven forces. Surface-enhanced Raman spectrometry (SERS) is employed as a reliable detection method for bacteria identification. To gain the effect of surface enhancement, silver nanoparticles were added to the sample. The pores of the membrane act as a filter trapping the bodies of microorganisms as well as clusters of nanoparticles creating suitable conditions for sensitive SERS detection. Therein, we focused on the construction and characterization of the device performance. To demonstrate the functionality of the microfluidic chip, we analyzed common pathogens (Escherichia coli DH5α and Pseudomonas taiwanensis VLB120) from spiked tap water using the optimized experimental parameters. The obtained results confirmed our system to be promising for the construction of a disposable optical platform for reliable and rapid pathogen detection which couples their electrokinetic concentration on the integrated nanoporous membrane with SERS detection.
- MeSH
- design vybavení MeSH
- kovové nanočástice chemie MeSH
- laboratoř na čipu * MeSH
- mikrofluidní analytické techniky přístrojové vybavení MeSH
- pitná voda mikrobiologie MeSH
- Ramanova spektroskopie přístrojové vybavení MeSH
- stříbro chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The study of optical affinity biosensors based on plasmonic nanostructures has received significant attention in recent years. The sensing surfaces of these biosensors have complex architectures, often composed of localized regions of high sensitivity (electromagnetic hot spots) dispersed along a dielectric substrate having little to no sensitivity. Under conditions such that the sensitive regions are selectively functionalized and the remaining regions passivated, the rate of analyte capture (and thus the sensing performance) will have a strong dependence on the nanoplasmonic architecture. Outside of a few recent studies, there has been little discussion on how changes to a nanoplasmonic architecture will affect the rate of analyte transport. We recently proposed an analytical model to predict transport to such complex architectures; however, those results were based on numerical simulation and to date, have only been partially verified. In this study we measure the characteristics of analyte transport across a wide range of plasmonic structures, varying both in the composition of their base plasmonic element (microwires, nanodisks, and nanorods) and the packing density of such elements. We functionalized each structure with nucleic acid-based bioreceptors, where for each structure we used analyte/receptor sequences as to maintain a Damköhler number close to unity. This method allows to extract both kinetic (in the form of association and dissociation constants) and analyte transport parameters (in the form of a mass transfer coefficient) from sensorgrams taken from each substrate. We show that, despite having large differences in optical characteristics, measured rates of analyte transport for all plasmonic structures match very well to predictions using our previously proposed model. These results highlight that, along with optical characteristics, analyte transport plays a large role in the overall sensing performance of a nanoplasmonic biosensor.
Most embryonic ventricular cardiomyocytes are quite uniform, in contrast to the adult heart, where the specialized ventricular conduction system is molecularly and functionally distinct from the working myocardium. We thus hypothesized that the preferential conduction pathway within the embryonic ventricle could be dictated by trabecular geometry. Mouse embryonic hearts of the Nkx2.5:eGFP strain between ED9.5 and ED14.5 were cleared and imaged whole mount by confocal microscopy, and reconstructed in 3D at 3.4 μm isotropic voxel size. The local orientation of the trabeculae, responsible for the anisotropic spreading of the signal, was characterized using spatially homogenized tensors (3 × 3 matrices) calculated from the trabecular skeleton. Activation maps were simulated assuming constant speed of spreading along the trabeculae. The results were compared with experimentally obtained epicardial activation maps generated by optical mapping with a voltage-sensitive dye. Simulated impulse propagation starting from the top of interventricular septum revealed the first epicardial breakthrough at the interventricular grove, similar to experimentally obtained activation maps. Likewise, ectopic activation from the left ventricular base perpendicular to dominant trabecular orientation resulted in isotropic and slower impulse spreading on the ventricular surface in both simulated and experimental conditions. We conclude that in the embryonic pre-septation heart, the geometry of the A-V connections and trabecular network is sufficient to explain impulse propagation and ventricular activation patterns.
- Publikační typ
- časopisecké články MeSH
This study presents a mathematical model, which expresses the absorbance of a photosynthetic sample as a non-linear polynomial of selected reference absorbance. The non-linearity is explained by inhomogeneities of a product of pigment concentration and light path length in the sample. The quadratic term of the polynomial reflects the extent of inhomogeneities, and the cubic term is related to deviation of the product distribution from a symmetric one. The model was tested by measurements of suspension of unstacked tobacco thylakoid membranes of different chlorophyll concentrations in cuvettes of different thicknesses. The absorbance was calculated from the diffuse transmittance and reflectance of sample, illuminated by perpendicular collimated light. The evaluated quantity was a sensitivity defined as the relative difference between the sample absorbance and the reference absorbance to the reference absorbance. The non-linearity of sample absorbance was demonstrated by a characteristic deviation of the sensitivity spectrum from a constant value. The absorbance non-linearity decreased on an increase of the product of pigment concentration and cuvette thickness. The model suggests that the sieve and detour effects influence the absorbance in a similar way. The model may be of interest in modeling of leaf or canopy optics including light absorption and scattering.
- MeSH
- chlorofyl metabolismus MeSH
- fotosyntéza účinky záření MeSH
- listy rostlin fyziologie účinky záření MeSH
- pigmentace účinky záření MeSH
- světlo MeSH
- tabák fyziologie účinky záření MeSH
- technologie dálkového snímání MeSH
- teoretické modely * MeSH
- tylakoidy účinky záření MeSH
- Publikační typ
- časopisecké články MeSH
Granulocytic early progenitors and terminally differentiated - mature granulocytes with segmented nuclei were studied using computer-assisted diameter and heterochromatin optical image densitometry to provide more information on the nuclear size and heterochromatin condensation state. Bone marrow smears of patients suffering from chronic myeloid leukaemia untreated as well as treated with "specific" anti-leukaemic therapy with imatinib mesylate are a convenient model for such study because they possess a satisfactory number of cells for diameter and optical density measurements. In addition, the identification of developmental stages of granulocytes is very easy and the morphology is not different from that in not-leukaemic persons. As it was expected, the mean diameter of nuclear segments in fully differentiated and mature granulocytes was much smaller than that in non-segmented nuclei of early granulocytic precursors. Therefore, no wonder that the heterochromatin condensation state in nuclear segments of mature granulocytes was much larger than in non-segmented nuclei of granulocytic progenitors. On the other hand, the sum of mean diameters of all nuclear segments per cell was close to the mean nuclear diameter of early granulocytic progenitors. The heterochromatin condensation state in granulocytic progenitors or fully differentiated mature granulocytes exhibited marked stability and did not change after the anti-leukaemic therapy. In addition, Barr bodies of characteristic drumstick appearance bearing inactive X chromosome in interphase nuclei of mature granulocytes in fertile female patients exhibited a heterochromatin condensation state similar to nuclear segments. This heterochromatin condensation state was also stable and constant, and was not apparently influenced by the anti-leukaemic therapy.
- MeSH
- biologické modely MeSH
- buněčná diferenciace * MeSH
- buněčný rodokmen * MeSH
- chronická myeloidní leukemie patologie MeSH
- denzitometrie metody MeSH
- granulocyty patologie MeSH
- heterochromatin chemie MeSH
- lidé MeSH
- prekurzorové buňky granulocytů patologie MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
