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1.
Environ Res ; 259: 119432, 2024 Jun 27.
Article in English | MEDLINE | ID: mdl-38944104

ABSTRACT

The Mediterranean Basin has experienced substantial land use changes as traditional agriculture decreased and population migrated from rural to urban areas, which have resulted in a large forest cover increase. The combination of Landsat time series, providing spectral information, with lidar, offering three-dimensional insights, has emerged as a viable option for the large-scale cartography of forest structural attributes across large time spans. Here we develop and test a comprehensive framework to map forest above ground biomass, canopy cover and forest height in two regions spanning the most representative biomes in the peninsular Spain, Mediterranean (Madrid region) and temperate (Basque Country). As reference, we used lidar-based direct estimates of stand height and forest canopy cover. The reference biomass and volume were predicted from lidar metrics. Landsat time series predictors included annual temporal profiles of band reflectance and vegetation indices for the 1985-2023 period. Additional predictor variables including synthetic aperture radar, disturbance history, topography and forest type were also evaluated to optimize forest structural attributes retrieval. The estimates were independently validated at two temporal scales, i) the year of model calibration and ii) the year of the second lidar survey. The final models used as predictor variables only Landsat based metrics and topographic information, as the available SAR time-series were relatively short (1991-2011) and disturbance information did not decrease the estimation error. Model accuracies were higher in the Mediterranean forests when compared to the temperate forests (R2 = 0.6-0.8 vs. 0.4-0.5). Between the first (1985-1989) and the last (2020-2023) decades of the monitoring period the average forest cover increased from 21 ± 2% to 32 ± 1%, mean height increased from 6.6 ± 0.43 m to 7.9 ± 0.18 m and the mean biomass from 31.9 ± 3.6 t ha-1 to 50.4 ± 1 t ha-1 for the Mediterranean forests. In temperate forests, the average canopy cover increased from 55 ± 4% to 59 ± 3%, mean height increased from 15.8 ± 0.77 m to 17.3 ± 0.21m, while the growing stock volume increased from 137.8 ± 8.2 to 151.5 ± 3.8 m3 ha-1. Our results suggest that multispectral data can be successfully linked with lidar to provide continuous information on forest height, cover, and biomass trends.

2.
Gels ; 10(4)2024 Mar 28.
Article in English | MEDLINE | ID: mdl-38667649

ABSTRACT

In this study, bismuth- and iron-embedded carbon xerogels (XG) were obtained using a modified resorcinol formaldehyde sol-gel synthesis method followed by additional enrichment with iron content. Pyrolysis treatment was performed at elevated temperatures under Ar or N2 atmosphere to obtain nanocomposites with different reduction yields (XGAr or XGN). The interest was focused on investigating the extent to which changes in the pyrolysis atmosphere of these nanocomposites impact the structure, morphology, and electrical properties of the material and consequently affect the electroanalytical performance. The structural and morphological particularities derived from X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) measurements revealed the formation of the nanocomposite phases, mostly metal/oxide components. The achieved performances for the two modified electrodes based on XG treated under Ar or N2 atmosphere clearly differ, as evidenced by the electroanalytical parameters determined from the detection of heavy metal cations (Pb2+) or the use of the square wave voltammetry (SWV) technique, biomarkers (H2O2), or amperometry. By correlating the differences obtained from electroanalytical measurements with those derived from morphological, structural, and surface data, a few utmost important aspects were identified. Pyrolysis under Ar atmosphere favors a significant increase in the α-Fe2O3 amount and H2O2 detection performance (sensitivity of 0.9 A/M and limit of detection of 0.17 µM) in comparison with pyrolysis under N2 (sensitivity of 0.5 A/M and limit of detection of 0.36 µM), while pyrolysis under N2 atmosphere leads to an increase in the metallic Bi amount and Pb2+ detection performance (sensitivity of 8.44 × 103 A/M and limit of detection of 33.05 pM) in comparison with pyrolysis under Ar (sensitivity of 6.47·103 A/M and limit of detection of 46.37 pM).

3.
Gels ; 9(11)2023 Oct 31.
Article in English | MEDLINE | ID: mdl-37998958

ABSTRACT

Multifunctional materials based on carbon xerogel (CX) with embedded bismuth (Bi) and iron (Fe) nanoparticles are tested for ultrasensitive amperometric detection of lead cation (Pb2+) and hydrogen peroxide (H2O2). The prepared CXBiFe-T nanocomposites were annealed at different pyrolysis temperatures (T, between 600 and 1050 °C) and characterized by X-ray diffraction (XRD), Raman spectroscopy, N2 adsorption, dynamic light scattering (DLS), and electron microscopies (SEM/EDX and TEM). Electrochemical impedance spectroscopy (EIS) and square wave anodic stripping voltammetry (SWV) performed at glassy carbon (GC) electrodes modified with chitosan (Chi)-CXBiFe-T evidenced that GC/Chi-CXBiFe-1050 electrodes exhibit excellent analytical behavior for Pb2+ and H2O2 amperometric detection: high sensitivity for Pb2+ (9.2·105 µA/µM) and outstanding limits of detection (97 fM, signal-to-noise ratio 3) for Pb2+, and remarkable for H2O2 (2.51 µM). The notable improvements were found to be favored by the increase in pyrolysis temperature. Multi-scale parameters such as (i) graphitization, densification of carbon support, and oxide nanoparticle reduction and purification were considered key aspects in the correlation between material properties and electrochemical response, followed by other effects such as (ii) average nanoparticle and Voronoi domain dimensions and (iii) average CXBiFe-T aggregate dimension.

4.
Molecules ; 28(2)2023 Jan 04.
Article in English | MEDLINE | ID: mdl-36677533

ABSTRACT

The hydration process of Portland cement is still not completely understood. For instance, it is not clear what produces the induction period, which follows the initial period of fast reaction, and is characterized by a reduced reactivity. To contribute to such understanding, we compare here the hydration process of two cement samples, the simple cement paste and the cement paste containing calcium nitrate as an accelerator. The hydration of these samples is monitored during the induction period using two different low-field nuclear magnetic resonance (NMR) relaxometry techniques. The transverse relaxation measurements of the 1H nuclei at 20 MHz resonance frequency show that the capillary pore water is not consumed during the induction period and that this stage is shortened in the presence of calcium nitrate. The longitudinal relaxation measurements, performed at variable Larmor frequency of the 1H nuclei, reveal a continuous increase in the surface-to-volume ratio of the capillary pores, even during the induction period, and this increase is faster in the presence of calcium nitrate. The desorption time of water molecules from the surface was also evaluated, and it increases in the presence of calcium nitrate.

5.
Materials (Basel) ; 15(14)2022 Jul 14.
Article in English | MEDLINE | ID: mdl-35888366

ABSTRACT

Bone scaffolds must fulfil numerous and sometimes contradictory characteristics: biocompatibility, bioactivity, high porosity, and appropriate mechanical strength. To tackle some of these issues, this study has several aims for the development of such scaffolds for dentistry applications: (i) to utilize appropriate materials (ceramics and sponges) and to introduce a novel, potentially performant ceramic material; (ii) to characterize the obtained scaffolds by using a range of methods; (iii) to compare and to correlate the assessment results with the scope to validate them reciprocally. There are two commercially available dental ceramics (i.e., Ceramco iC Natural Enamel (E) and Ceramco iC Natural Dentine (D), (DeguDent GmbH, Hanau-Wolfgang, Deutschland)) that are considered, as well as a new-developed porcelain (ceramic C). To obtain porous structures of scaffolds, each ceramic is introduced in two different sponges: a denser one, green (G) and a less dense one, blue (B). A total of 60 samples are manufactured and divided in six study groups, obtained by combining the above materials: GE, BE, GD, BD, GC, and BC (where the first letter represents the sponge type and the second one the utilized ceramic). Several methods are applied to characterize their chemical composition, as well as their macro- and micro-porosity: X-ray Diffraction (XRD), apparent porosity measurements, scanning electronic microscopy (SEM), and confocal microscopy (CM). The latter two methods image the inner (porous) and the outer/cortical (denser) areas of the samples. The results show a good porosity (i.e., dimensions and uniformity of pores) of around 65% for the final group BC, with satisfactory values of around 51% for BD and GC. A certain correlation is made between SEM, CM, and the apparent porosity results. The biocompatibility of the new ceramic C is demonstrated. Finally, a necessary trade-off is made with the mechanical strength of the obtained scaffolds, which was also evaluated. From this point of view, Group BD has the highest compressive strength of around 4 MPa, while Group BC comes second, with around 2 MPa. This trade-off between porosity and mechanical strength suggests a choice between Groups BC and BD, which are the best with regard to the porosity and mechanical strength criterium, respectively.

6.
Microsc Microanal ; : 1-13, 2022 Mar 01.
Article in English | MEDLINE | ID: mdl-35229707

ABSTRACT

Carbon xerogel nanocomposites with integrated Bi and Fe particles (C­Bi­Fe) represent an interesting model of carbon nanostructures decorated with multifunctional nanoparticles (NPs) with applicability for electrochemical sensors and catalysts. The present study addresses the fundamental aspects of the catalyzed growth of nano-graphites in C­Bi­Fe systems, relevant in charge transport and thermo-chemical processes. The thermal evolution of a C­Bi­Fe xerogel is investigated using different pyrolysis treatments. At lower temperatures (~750°C), hybrid bismuth iron oxide (BFO) NPs are frequently observed, while graphitization manifests under more specific conditions such as higher temperatures (~1,050°C) and reduction yields. An in situ heating TEM experiment reveals graphitization activity between 800 and 900°C. NP motion is directly correlated with textural changes of the carbon support due to the catalyzed growth of graphitic nanoshells and nanofibers as confirmed by HR-TEM and electron tomography (ET) for the graphitized sample. An exponential growth model for the catalyst dynamics enables the approximation of activation energies as 0.68 and 0.29­0.34 eV during reduction and graphitization stages. The results suggest some similarities with the tip growth mechanism, while oxygen interference and the limited catalyst­feed gas interactions are considered as the main constraints to enhanced growth.

7.
Acta Endocrinol (Buchar) ; 17(2): 274-277, 2021.
Article in English | MEDLINE | ID: mdl-34925580

ABSTRACT

BACKGROUND: Hidradenitis suppurativa (HS) is a chronic, debilitating disease with a profound impact on the quality of life of patients. OBJECTIVES: To describe a rare case of HS with postmenopausal onset, to review the literature data regarding late onset HS and to discuss the current knowledge on the role of endocrine abnormalities in the development of HS. CASE REPORT: We report the case of a 68-year-old patient in whom HS occurred 10 years after menopause. She was referred to our clinic for the presence of an open fistula on the left groin, fibrotic scars and visible alteration of the vulvar anatomy due to numerous surgical interventions. The patient shared features of the metabolic syndrome (obesity, arterial hypertension, dyslipidemia, aortic atherosclerosis), but showed no signs of virilism and no hormonal abnormality. HS was controlled using antiseptics, topical retinoids and antibiotics. CONCLUSIONS: This case is of particular interest given the late onset of HS, long time after menopause. The development of HS requires a complex interaction between genetic predisposing factors, endocrine dysregulation, metabolic alterations, bacterial overgrowth and an aberrant inflammatory response. Evidence points to an important role of sex-hormones in the emergence and progression of the disease, but the underlying mechanisms are still unclear. A better understanding of HS pathogenesis is needed to elucidate the precise way in which endocrine factors influence the disease onset and course. This would guide the way to novel therapies and a better control of this challenging disease.

8.
Materials (Basel) ; 14(9)2021 Apr 27.
Article in English | MEDLINE | ID: mdl-33925656

ABSTRACT

The design and development of ceramic structures based on 3D scaffolding as dental bone substitutes has become a topic of great interest in the regenerative dentistry research area. In this regard, the present study focuses on the development of two scaffold-type structures obtained from different commercial dental ceramics by employing the foam replication method. At the same time, the study underlines the physicochemical features and the biological profiles of the newly developed scaffolds, compared to two traditional Cerabone® materials used for bone augmentation, by employing both the in vitro Alamar blue proliferation test at 24, 48 and 96 h poststimulation and the in ovo chick chorioallantoic membrane (CAM) assay. The data reveal that the newly developed scaffolds express comparable results with the traditional Cerabone® augmentation masses. In terms of network porosity, the scaffolds show higher pore interconnectivity compared to Cerabone® granules, whereas regarding the biosafety profile, all ceramic samples manifest good biocompatibility on primary human gingival fibroblasts (HGFs); however only the Cerabone® samples induced proliferation of HGF cells following exposure to concentrations of 5 and 10 µg/mL. Additionally, none of the test samples induce irritative activity on the vascular developing plexus. Thus, based on the current results, the preliminary biosecurity profile of ceramic scaffolds supports the usefulness for further testing of high relevance for their possible clinical dental applications.

9.
J Nanosci Nanotechnol ; 21(4): 2323-2333, 2021 04 01.
Article in English | MEDLINE | ID: mdl-33500048

ABSTRACT

In order to obtain a multifunctional nanocomposite material-for electrochemical sensors and photocatalytic applications, structures based on Bi, Fe and TiO2 were grown inside carbon xerogel supports (BiFeCX and BiFeCX-TiO2). First, a wet polymer containing Bi and Fe salts was obtained by following a modified resorcinol-formaldehyde based sol-gel route, followed by drying in ambient conditions, and pyrolysis under inert atmosphere. Then, through TiCl4 hydrolysis, TiO2 nanoparticles were deposited on the BiFeCX xerogel leading to BiFeCX-TiO2. The morphological and structural characterization of the investigated nanocomposites consisted in X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy and N2 adsorption measurements, revealing porous carbon structures with embedded nanoparticles and the particularities driven by the pyrolysis and TiCl4 treatment. The new modified electrodes based on BiFeCX or BiFeCX-TiO2 nanocomposite materials, kept in a chitosan matrix (Chi) and deposited on a glassy carbon (GC) electrode surface (GC/Chi-BiFeCX or GC/Chi-BiFeCX-TiO2), were obtained and investigated for Pb(II) voltammetric detection and H2O2 amperometric detection. Moreover, the BiFeCX-TiO2 nanocomposite was tested for the photocatalytic degradation of methyl orange. The great potential of BiFeCX nanocomposite material for developing electrochemical sensors, or BiFeCX-TiO2 for sensors application and photocatalytic application was demonstrated.

10.
Molecules ; 26(1)2020 Dec 29.
Article in English | MEDLINE | ID: mdl-33383893

ABSTRACT

Multifunctional Bi- and Fe-modified carbon xerogel composites (CXBiFe), with different Fe concentrations, were obtained by a resorcinol-formaldehyde sol-gel method, followed by drying in ambient conditions and pyrolysis treatment. The morphological and structural characterization performed by X-ray diffraction (XRD), Raman spectroscopy, N2 adsorption/desorption porosimetry, scanning electron microscopy (SEM) and scanning/transmission electron microscopy (STEM) analyses, indicates the formation of carbon-based nanocomposites with integrated Bi and Fe oxide nanoparticles. At higher Fe concentrations, Bi-Fe-O interactions lead to the formation of hybrid nanostructures and off-stoichiometric Bi2Fe4O9 mullite-like structures together with an excess of iron oxide nanoparticles. To examine the effect of the Fe content on the electrochemical performance of the CXBiFe composites, the obtained powders were initially dispersed in a chitosan solution and applied on the surface of glassy carbon electrodes. Then, the multifunctional character of the CXBiFe systems is assessed by involving the obtained modified electrodes for the detection of different analytes, such as biomarkers (hydrogen peroxide) and heavy metal ions (i.e., Pb2+). The achieved results indicate a drop in the detection limit for H2O2 as Fe content increases. Even though the current results suggest that the surface modifications of the Bi phase with Fe and O impurities lower Pb2+ detection efficiencies, Pb2+ sensing well below the admitted concentrations for drinkable water is also noticed.


Subject(s)
Bismuth/chemistry , Carbon/chemistry , Hydrogen Peroxide/analysis , Iron/chemistry , Lead/analysis , Nanostructures/chemistry , Electrochemical Techniques/instrumentation , Electrochemical Techniques/methods , Electrodes , Equipment Design , Gels/chemistry , Metals, Heavy/analysis
11.
Platelets ; 29(6): 602-609, 2018 Sep.
Article in English | MEDLINE | ID: mdl-28960117

ABSTRACT

Involvement of signal transducer and activator of transcription 3 (STAT3) in inflammation is well known. Recently, a role for STAT3 in platelet activation and platelet production has been suggested. Platelets exhibit important immune functions and engagement of STAT3 in platelet physiology may link inflammation and hemostasis. This study investigated the effects of STAT3 loss-of-function mutations and single nucleotide polymorphisms (SNPs) in STAT3 on glycoprotein VI (GPVI)-mediated platelet activation and platelet numbers in humans. Two cohorts were studied. The first cohort concerned patients with STAT3 loss-of-function mutations. Platelet numbers were investigated in eight patients and GPVI-mediated platelet activation was functionally tested in four patients. Additional experiments were performed to investigate underlying mechanisms. The second cohort concerned 334 healthy volunteers and investigated the consequences of SNPs in STAT3 on GPVI-mediated platelet activation and platelet numbers. Platelet activation was lower in STAT3 loss-of-function patients at baseline and after stimulation of the GPVI receptor, reflected by decreased P-selectin expression. This was independent of gene transcription. Blockade of the adenosine di-phosphate (ADP) pathway resulted in a further decrease of P-selectin expression, particularly in STAT3 loss-of-function patients. In contrast, the SNPs in STAT3 did not influence GPVI-mediated platelet activation. Also, platelet numbers were not affected by STAT3 loss-of-function mutations, nor was there an association with the SNPs. In conclusion, STAT3 signaling does not seem to play a major role in thrombopoiesis. We confirm that STAT3 is involved in GPVI-mediated platelet activation in humans, independent of gene transcription. GPVI-mediated platelet activation is highly dependent on secondary ADP release. Our findings suggest that STAT3 modulation may affect inflammation, hemostasis, and their interaction.


Subject(s)
Blood Platelets/metabolism , STAT3 Transcription Factor/metabolism , Hemostasis , Humans , Mutation , Signal Transduction
12.
World J Gastroenterol ; 21(6): 1728-37, 2015 Feb 14.
Article in English | MEDLINE | ID: mdl-25684937

ABSTRACT

Biological drugs opened up new horizons in the management of inflammatory bowel diseases (IBD). This study focuses on access to biological therapy in IBD patients across 9 selected Central and Eastern European (CEE) countries, namely Bulgaria, the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Romania and Slovakia. Literature data on the epidemiology and disease burden of IBD in CEE countries was systematically reviewed. Moreover, we provide an estimation on prevalence of IBD as well as biological treatment rates. In all countries with the exception of Romania, lower biological treatment rates were observed in ulcerative colitis (UC) compared to Crohn's disease despite the higher prevalence of UC. Great heterogeneity (up to 96-fold) was found in access to biologicals across the CEE countries. Poland, Bulgaria, Romania and the Baltic States are lagging behind Hungary, Slovakia and the Czech Republic in their access to biologicals. Variations of reimbursement policy may be one of the factors explaining the differences to a certain extent in Bulgaria, Latvia, Lithuania, and Poland, but association with other possible determinants (differences in prevalence and incidence, price of biologicals, total expenditure on health, geographical access, and cost-effectiveness results) was not proven. We assume, nevertheless, that health deterioration linked to IBD might be valued differently against other systemic inflammatory conditions in distinct countries and which may contribute to the immense diversity in the utilization of biological drugs for IBD. In conclusion, access to biologicals varies widely among CEE countries and this difference cannot be explained by epidemiological factors, drug prices or total health expenditure. Changes in reimbursement policy could contribute to better access to biologicals in some countries.


Subject(s)
Anti-Inflammatory Agents/therapeutic use , Biological Products/therapeutic use , Colitis, Ulcerative/drug therapy , Crohn Disease/drug therapy , Practice Patterns, Physicians'/trends , Anti-Inflammatory Agents/adverse effects , Anti-Inflammatory Agents/economics , Biological Products/adverse effects , Biological Products/economics , Colitis, Ulcerative/diagnosis , Colitis, Ulcerative/economics , Colitis, Ulcerative/epidemiology , Colitis, Ulcerative/immunology , Crohn Disease/diagnosis , Crohn Disease/economics , Crohn Disease/epidemiology , Crohn Disease/immunology , Drug Costs , Europe, Eastern/epidemiology , Health Services Accessibility/trends , Healthcare Disparities/trends , Humans , Insurance, Health, Reimbursement , Practice Patterns, Physicians'/economics , Prevalence , Treatment Outcome
13.
Radiat Prot Dosimetry ; 162(1-2): 167-70, 2014 Nov.
Article in English | MEDLINE | ID: mdl-25071243

ABSTRACT

The radiotherapy centres are using linear accelerators equipped with multi-leaf collimators (MLCs) for treatments of various types of cancer. For superficial cancers located at a maximum depth of 3 cm high-energy electrons are often used, but MLC cannot be used together with electron applicators. Due to the fact that the tumour shape is not square (as electron applicators), searching for different materials that can be used as absorbents or shields for the protection of adjacent organs is of paramount importance. This study presents an experimental study regarding the transmitted dose through some laboratory-made materials when subjected to electron beams of various energies (ranging from 6 to 15 MeV). The investigated samples were composite materials consisting of silicon rubber and micrometre aluminium particles with different thicknesses and various mass fraction of aluminium. The measurements were performed at a source surface distance of 100 cm in the acrylic phantom. The experimental results show that the transmitted dose through tested samples is ranging between ∼1.8 and 90%, depending on the electron beam energy, sample thickness and sample composition. These preliminary results suggest that the analysed materials can be used as absorbers or shields in different applications in radiotherapy and radioprotection.


Subject(s)
Electrons , Particle Accelerators/instrumentation , Photons , Radiation Protection , Aluminum/chemistry , Humans , Monte Carlo Method , Phantoms, Imaging , Radiotherapy Dosage , Silicon/chemistry
14.
J Med Life ; 5(1): 101-4, 2012 Feb 22.
Article in English | MEDLINE | ID: mdl-22574096

ABSTRACT

RATIONALE: About 95% of prostate cancers are adenocarcinoamas. Depending on the detection method used, neuroendocrine cells are found in 10% to 100% of prostate cancer specimens. OBJECTIVE: A 64-year-old patient was diagnosed in 2006 with adenocarcinoma of the prostate, PSA 4.1 ng/ml, Gleason 6, T3b, positive PSA immunohistochemistry. METHODS AND RESULTS: The patient was started on hormone therapy: orchidectomy followed by flutamide 750 mg/day for three years, and underwent radiotherapy 6400 R. The patient was asymptomatic for three years. In 2009, the patient complained of perineal and rectal pain, but the PSA remained normal. In 2010, the patient underwent TUR of the prostate for acute urinary retention. Pathological exam revealed Gleason 8 adenocarcinoma of the prostate (different pathologist suggested Gleason 9) and foci of neuroendocrine cells. Immunohistochemistry detected 15-20% positivity for Cromogranin A and 10% for synaptophysin. The patient developed multiple liver metastases in October 2010 and underwent five cycles of etoposide, carboplatin. The patient died of liver failure in March 2011. DISCUSSION: Regarding prevalence, neuroendocrine differentiation is the second phenotype after prostate adenocarcinoma, but still remains undiagnosed. It is resistant to radiation therapy and chemotherapy. Detection of the neuroendocrine differentiation is recommended during the clinical, biochemical, histopathological and immunohistochemical follow up of prostate cancer patients treated by EBRT and / or androgen deprivation.


Subject(s)
Adenocarcinoma/pathology , Carcinoma, Neuroendocrine/pathology , Cell Transdifferentiation/physiology , Prostatic Neoplasms/pathology , Adenocarcinoma/diagnostic imaging , Adenocarcinoma/radiotherapy , Aged , Carcinoma, Neuroendocrine/diagnostic imaging , Carcinoma, Neuroendocrine/radiotherapy , Fatal Outcome , Humans , Immunohistochemistry , Liver Neoplasms/secondary , Magnetic Resonance Imaging , Male , Prostate-Specific Antigen/analysis , Prostatic Neoplasms/diagnostic imaging , Prostatic Neoplasms/radiotherapy , Radiotherapy/methods , Romania , Synaptophysin/analysis , Tomography, X-Ray Computed
15.
J Am Soc Hypertens ; 4(3): 116-27, 2010.
Article in English | MEDLINE | ID: mdl-20470996

ABSTRACT

The impressive cardiovascular morbidity and mortality of chronic kidney disease (CKD) patients is attributable in a significant proportion to endothelial dysfunction (ED), arterial stiffness, and vascular calcifications. Abnormal vascular reactivity in these patients is more pronounced compared with other high-risk populations, but remains undiagnosed in the usual clinical setting. We briefly review the most important causes and risk factors of ED, oxidative stress, and inflammation related to arterial stiffness. We describe the main methods of ED investigation and the importance of using potential biomarkers together with classic techniques for a more comprehensive assessment of this condition. These methods include evaluation of: forearm blood flow by plethysmography, skin microcirculation by laser Doppler, and flow-mediated vasodilation by Doppler ultrasound imaging. Applanation tonometry is an easy-to-handle tool that allows a clinically reliable assessment of arterial stiffness and is also useful in quantifying endothelium-dependent and -independent vascular reactivity. We also discuss the diagnostic and therapeutic impact of new markers of ED in the CKD population. Improvement of endothelial function is an important challenge for clinical practice, and there are relatively few therapeutical strategies available. Therefore, a combined biomarker and bedside investigational approach could be a starting point for developing optimal therapeutic tools.


Subject(s)
Biomarkers/metabolism , Endothelium, Vascular/physiopathology , Kidney Failure, Chronic/physiopathology , Vasodilation/physiology , Endothelium, Vascular/metabolism , Humans , Kidney Failure, Chronic/metabolism
16.
IEEE Trans Med Imaging ; 25(3): 297-311, 2006 Mar.
Article in English | MEDLINE | ID: mdl-16524086

ABSTRACT

This paper introduces a novel nonlinear multiscale wavelet diffusion method for ultrasound speckle suppression and edge enhancement. This method is designed to utilize the favorable denoising properties of two frequently used techniques: the sparsity and multiresolution properties of the wavelet, and the iterative edge enhancement feature of nonlinear diffusion. With fully exploited knowledge of speckle image models, the edges of images are detected using normalized wavelet modulus. Relying on this feature, both the envelope-detected speckle image and the log-compressed ultrasonic image can be directly processed by the algorithm without need for additional preprocessing. Speckle is suppressed by employing the iterative multiscale diffusion on the wavelet coefficients. With a tuning diffusion threshold strategy, the proposed method can improve the image quality for both visualization and auto-segmentation applications. We validate our method using synthetic speckle images and real ultrasonic images. Performance improvement over other despeckling filters is quantified in terms of noise suppression and edge preservation indices.


Subject(s)
Algorithms , Artifacts , Image Enhancement/methods , Image Interpretation, Computer-Assisted/methods , Imaging, Three-Dimensional/methods , Ultrasonography/methods , Artificial Intelligence , Humans , Models, Biological , Models, Statistical , Nonlinear Dynamics , Pattern Recognition, Automated/methods , Reproducibility of Results , Sensitivity and Specificity
17.
Conf Proc IEEE Eng Med Biol Soc ; 2005: 6429-32, 2005.
Article in English | MEDLINE | ID: mdl-17281740

ABSTRACT

This paper introduces a novel multiscale nonlinear wavelet diffusion (MNWD) method for ultrasound speckle suppression and edge enhancement. It considers wavelet diffusion as an approximation to nonlinear diffusion within the framework of the dyadic wavelet transform. Consequently, this knowledge is exploited in the design of a speckle suppression filter with an edge enhancement feature. MNWD takes advantage of the sparsity and multiresolution properties of wavelet, and the iterative edge enhancement feature of nonlinear diffusion. In our algorithm, speckle is suppressed by employing the iterative multiscale diffusion on the wavelet coefficients, while the edges of the image are enhanced by using an iterative signal compensation process. We validate the proposed method using synthetic and real echocardiographic images. Performance improvement over other traditional denoising filters is quantified in terms of noise suppression and structural preservation indices. The application of the proposed method is demonstrated by the segmentation of the echocardiographic image using the active contour.

18.
Rom J Morphol Embryol ; 45: 63-72, 1999.
Article in English | MEDLINE | ID: mdl-15847380

ABSTRACT

The aim was to evaluate the cellular immune response in atypical tuberculosis and granulomatous inflammation consistent with tuberculosis (TBC), negative histochemically for acid-fast bacilli and analysed by PCR for Mycobacterium tuberculosis (MT) detection in paraffin-embedded tissue. Thirty six samples of differently localized atypical tuberculous lesions and granulomatous tuberculoid lesions negative for acid fast bacilli and 4 positive cases on Ziehl-Nielsen stain were analysed by PCR for MT detection and were tested immunohistochemically (IHC) for the cellular immune response in the granulomas and perigranulomatous tissue. The samples selected were: 7 pulmonary and 33 extrapulmonary specimens, especially lymph nodes. Histologically, the atypical tuberculous lesions contained supurative necrosis, defective granulomas and cellular polymorphism. The epithelioid cells showed frequent mitoses. The immunoprofile of cells was polymorphous. L26 positive small lymphocytes were found in nodular lymphoid aggregates surrounding granulomas. A significantly increased number of positive UCHL1 cells were found in 33 out of the 40 analysed cases, with a larger percentage of CD4 positive T cells (81.8% of cases). CD44 was positive in multinucleated giant cells (17.5% of cases), epithelioid cells (60% of cases) and lymphocytes (30% of cases). CD68 was localized in multinucleated giant cells and epithelioid cells, in a 4%, respectively 62.5% of cases. The PCR was performed in all 40 cases; the tissue samples were heterogeneous (lung, lymph nodes, lever, nasopharynx, etc.) and needed a good quality extraction of DNA. Performing a control PCR for Beta Globin tested the extraction; a good result was obtained in 31 cases (77.5%); from these, 19 cases had amplification for IS 6110. The cellular immune response in the atypical tuberculous lesions was similar in cases with and without acid-fast bacilli, but positive for PCR. In the most cases with negative PCR reaction, it was due to a deficient fixation of the material. The T lymphocytes were numerous in all types of tuberculous granulomas, with the prominence of CD4 positive subtype. The immunoprofile of the epithelioid cells, positive for CD44 and CD68, presenting frequently mitoses suggests an activate state in a possible relationship to the T-cell-mediated immune response in tuberculosis.


Subject(s)
Granuloma/immunology , Lung/microbiology , Tuberculosis, Pulmonary/immunology , Antigens, CD/immunology , Epithelioid Cells/immunology , Epithelioid Cells/microbiology , Epithelioid Cells/pathology , Female , Granuloma/diagnosis , Granuloma/microbiology , Granuloma/pathology , Humans , Immunohistochemistry , Kupffer Cells/immunology , Kupffer Cells/microbiology , Kupffer Cells/pathology , Lung/immunology , Lung/pathology , Lymph Nodes/immunology , Lymph Nodes/microbiology , Lymph Nodes/pathology , Lymphocytes/immunology , Male , Mycobacterium tuberculosis/genetics , Mycobacterium tuberculosis/isolation & purification , Necrosis , Paraffin Embedding , Polymerase Chain Reaction , Tuberculosis, Pulmonary/diagnosis , Tuberculosis, Pulmonary/microbiology , Tuberculosis, Pulmonary/pathology
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