Analytic procedure for the evaluation of copper intermetallic diffusion in electroplated gold coatings with energy dispersive X-ray microanalysis.

A method for the determination of the intermetallic diffusion coefficient in the Cu-Au system is described based on energy dispersive X-ray techniques. XRF and EDS analysis were used to measure the thickness of the electroplated gold coating and the copper diffused through it, respectively. This information was used to obtain the diffusion coefficient through an equation based on Fick's law. Colour measurements and metallographic section analysis of the samples were also performed to evaluate alternative methods for a qualitative determination of diffusion rate. The thickness of the gold layer was chosen in agreement with what is used in decorative and functional applications (<1 µm). The measurements were performed on samples heated in a range of temperatures between 100 °C and 200 °C from 12 to 96 h. The results obtained follow a linear trend between the logarithm of the diffusion coefficient and the inverse of the temperature and are in line with the values found in the literature.

Structure and mineralization of the spearing mantis shrimp (Stomatopoda; Lysiosquillina maculata) body and spike cuticles.

Stomatopoda is a crustacean order including sophisticated predators called spearing and smashing mantis shrimps that are separated from the well-studied Eumalacotraca since the Devonian. The spearing mantis shrimp has developed a spiky dactyl capable of impaling fishes or crustaceans in a fraction of second. In this high velocity hunting technique, the spikes undergo an intense mechanical constraint to which their exoskeleton (or cuticle) has to be adapted. To better understand the spike cuticle internal architecture and composition, electron microscopy, X-ray microanalysis and Raman spectroscopy were used on the spikes of 7 individuals (collected in French Polynesia and Indonesia), but also on parts of the body cuticle that have less mechanical stress to bear. In the body cuticle, several specificities linked to the group were found, allowing to determine the basic structure from which the spike cuticle has evolved. Results also highlighted that the body cuticle of mantis shrimps could be a model close to the ancestral arthropod cuticle by the aspect of its biological layers (epi- and procuticle including exo- and endocuticle) as well as by the Ca-carbonate/phosphate mineral content of these layers. In contrast, the spike cuticle exhibits a deeply modified organization in four functional regions overprinted on the biological layers. Each of them has specific fibre arrangement or mineral content (fluorapatite, ACP or phosphate-rich Ca-carbonate) and is thought to assume specific mechanical roles, conferring appropriate properties on the entire spike. These results agree with an evolution of smashing mantis shrimps from primitive stabbing/spearing shrimps, and thus also allowed a better understanding of the structural modifications described in previous studies on the dactyl club of smashing mantis shrimps.

Power of Scanning Electron Microscopy and Energy Dispersive X-Ray Analysis in Rapid Microbial Detection and Identification at the Single Cell Level.

The demand for rapid, consistent and easy-to-use techniques for detecting and identifying pathogens in various areas, such as clinical diagnosis, the pharmaceutical industry, environmental science and food inspection, is very important. In this study, the reference strains of six food-borne pathogens, namely, Escherichia coli 0157: H7 ATCC 43890, Cronobacter sakazakii ATCC 29004, Salmonella Typhimurium ATCC 43971, Staphylococcus aureus KCCM 40050, Bacillus subtilis ATCC 14579, and Listeria monocytogenes ATCC 19115, were chosen for scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis. In our study, the time-consuming sample preparation step for the microbial analysis under SEM was avoided, which makes this detection process notably rapid. Samples were loaded onto a 0.01-µm-thick silver (Ag) foil surface to avoid any charging effect. Two different excitation voltages, 10 kV and 5 kV, were used to determine the elemental information. Information obtained from SEM-EDX can distinguish individual single cells and detect viable and nonviable microorganisms. This work demonstrates that the combination of morphological and elemental information obtained from SEM-EDX analysis with the help of principal component analysis (PCA) enables the rapid identification of single microbial cells without following time-consuming microbiological cultivation methods.

A scoping study of component-specific toxicity of mercury in urban road dusts from three international locations.

This scoping study presents an investigation of the total and bioaccessible mercury concentrations in road dust (RD) from three international urban sites, where a one-off sampling campaign was conducted at each. This was done to address the hypothesis that the matrix in which mercury is found influences its ability to become accessible to the body once inhaled. For that purpose, the samples were analysed for total and pulmonary bioaccessible mercury and the data compared to the chemical structure of individual particles by SEM. The results obtained from this study suggest that a high mercury content does not necessarily equate to high bioaccessibility, a phenomenon which could be ascribed to the chemical character of the individual particles. It was found that the Manchester samples contained more pulmonary soluble mercury species (as determined by elemental associations of Hg and Cl) in comparison to the other two samples, Curitiba, Brazil, and Johannesburg, South Africa. This finding ultimately underlines the necessity to conduct a site-specific in-depth analysis of RD, to determine the concentration, chemical structure and molecular speciation of the materials within the complex matrix of RD. Therefore, rather than simply assuming that higher bulk concentrations equate to more significant potential human health concerns, the leaching potential of the metal/element in its specific form (for example as a mineral) should be ascertained. The importance of individual particle behaviour in the determination of human health risk is therefore highlighted.

Valoración del ángulo de la cámara anterior mediante biomicroscopia ultrasónica, gonioscopia y examen de Van Herick / Evaluation of the angle of the anterior chamber using ultrasound biomicroscopy, gonioscopy and a Van Herick examination

Objetivo: Comparar la medición del ángulo de la cámara anterior mediante biomicroscopia ultrasónica (UBM), gonioscopia y examen de Van Herick. Métodos: Se realizó un estudio comparativo observacional entre 3 métodos diferentes para la estimación del ángulo iridocorneal. Fueron evaluados 30 sujetos con ángulos abiertos y cerrados a través del examen con UBM, gonioscopia y Van Herick. En la valoración con UBM y gonioscopia se incluyeron en el análisis todos los cuadrantes; en la estimación de Van Herick se analizaron los cuadrantes nasal y temporal. Todos los exámenes incluyeron la valoración de ambos ojos en condiciones de iluminación fotópica y escotópica. Estos hallazgos fueron comparados con la prueba de concordancia kappa. Resultados: No hubo diferencia estadísticamente significativa entre los 3métodos para evaluar el estado del ángulo iridocorneal. La consistencia entre UBM y gonioscopia fue mejor (kappa 0,93) con relación a la estimación del ángulo con Van Herick (kappa 0,83). Conclusiones: Los exámenes UBM, gonioscopia y Van Herick tienen resultados comparables. La gonioscopia en primera instancia estaría indicada como prueba de rutina para identificación de cierre angular

Objective: To compare the measurement of the angle of the anterior chamber using ultrasound biomicroscopy (UBM), gonioscopy and the Van Herick examination. Methods: An observational comparative study was carried out between 3different methods for the estimation of the iridocorneal angle. A total of 30 subjects with open and closed angles were evaluated using UBM, gonioscopy and Van Herick. In the UBM and gonioscopy assessment all the quadrants were included in the analysis, and in the Van Herick examination the nasal and temporal quadrant were also analysed. All the examinations included the assessment of both eyes under photo-optical and scotopic illumination conditions. These findings were compared with the kappa concordance test. Results: There was no statistically significant difference between the 3 methods in the evaluation of the state of the iridocorneal angle. The consistency between UBM and gonioscopy was better (kappa 0.93) in relation to the estimation of the angle with Van Herick (kappa 0.83). Conclusions: The UBM, gonioscopy and Van Herick examinations have comparable results, although gonioscopy in the first instance would be indicated as a routine test for identification of angular closure

In-situ preparation of plant samples in ESEM for energy dispersive x-ray microanalysis and repetitive observation in SEM and ESEM.

The Extended Low Temperature Method (ELTM) for the in-situ preparation of plant samples in an environmental scanning electron microscope enables carrying out repetitive topographical and material analysis at a higher resolution in the vacuum conditions of a scanning electron microscope or in the low gas pressure conditions of an environmental scanning electron microscope. The method does not require any chemical intervention and is thus suitable for imaging delicate structures rarely observable with common treatment methods. The method enables both sample stabilization as close to their native state as possible, as well as the transfer of the same sample from a low vacuum to an atmospheric condition for sample storage or later study. It is impossible for wet samples in the environmental scanning electron microscope. Our studies illustrate the high applicability of the ELTM for different types of plant tissue, from imaging of plant waxes at higher resolution, the morphological study of highly susceptible early somatic embryos to the elemental microanalysis of root cells. The method established here provides a very fast, universal and inexpensive solution for plant sample treatment usable in a commercial environmental scanning electron microscope equipped with a cooling Peltier stage.

Analysis of Minerals Produced by hFOB 1.19 and Saos-2 Cells Using Transmission Electron Microscopy with Energy Dispersive X-ray Microanalysis.

This video presents the use of transmission electron microscopy with energy dispersive X-ray microanalysis (TEM-EDX) to compare the state of minerals in vesicles released by two human bone cell lines: hFOB 1.19 and Saos-2. These cell lines, after treatment with ascorbic acid (AA) and ß-glycerophosphate (ß-GP), undergo complete osteogenic transdifferentiation from proliferation to mineralization and produce matrix vesicles (MVs) that trigger apatite nucleation in the extracellular matrix (ECM). Based on Alizarin Red-S (AR-S) staining and analysis of the composition of minerals in cell lysates using ultraviolet (UV) light or in vesicles using TEM imaging followed by EDX quantitation and ion mapping, we can infer that osteosarcoma Saos-2 and osteoblastic hFOB 1.19 cells reveal distinct mineralization profiles. Saos-2 cells mineralize more efficiently than hFOB 1.19 cells and produce larger mineral deposits that are not visible under UV light but are similar to hydroxyapatite (HA) in that they have more Ca and F substitutions. The results obtained using these techniques allow us to conclude that the process of mineralization differs depending on the cell type. We propose that, at the cellular level, the origin and properties of vesicles predetermine the type of minerals.

[Electronic probe analysis of enamel remineralization effect of casein phosphopeptide-amorphous calcium phosphate promoted by different concentrations of fluorine].

Objective: To evaluate the remineralization effect and mechanism of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) with different concentrations of fluorine on demineralized enamel using electronic probe. Methods: Extracted premolar teeth for orthodontic purpose were immersed into lactic acid gel to prepare artificial white spot lesions (10 teeth in each group). Then the specimens were randomly assigned to three groups: Control group, with 5% of the CPP-ACP+deionized water; Group A with 5% CPP-ACP+500 mg/L F(-) and Group B with 5% CPP-ACP+900 mg/L F(-). The teeth in each group were soaked in different solutions for 4 days and then were measured using electron probe tester. The changes of contents among the three groups were compared. Results: No statistically significant difference in the percentage of fluorine was found in the control group before and after treatment (P=0.06), and the difference in the percentage of fluorine quality in the other two groups was statistically significant (P<0.05). Statistically significant difference was found between calcium oxide and phosphorus peroxide in the three groups before and after mineralization (P<0.05). The percentage change of fluorine mass in group B [(0.107±0.035)%] was significantly greater than that in group A [(0.057±0.038)%] (P<0.05), while fluorine mass in group A was significantly greater than that in control group [(0.013±0.019)%] (P<0.05). In group A and group B, the change in quality of calcium oxide and phosphorus peroxide was significantly greater than that in control group (P<0.05), while no significant difference was found between group A and group B (P>0.05). Conclusions: The addition of fluorine in CPP-ACP increased the transport and penetration of calcium, phosphorus and fluorine on enamel surface.

Energy Dispersive X-ray (EDX) microanalysis: A powerful tool in biomedical research and diagnosis.

The Energy Dispersive X-ray (EDX) microanalysis is a technique of elemental analysis associated to electron microscopy based on the generation of characteristic Xrays that reveals the presence of elements present in the specimens. The EDX microanalysis is used in different biomedical fields by many researchers and clinicians. Nevertheless, most of the scientific community is not fully aware of its possible applications. The spectrum of EDX microanalysis contains both semi-qualitative and semi-quantitative information. EDX technique is made useful in the study of drugs, such as in the study of drugs delivery in which the EDX is an important tool to detect nanoparticles (generally, used to improve the therapeutic performance of some chemotherapeutic agents). EDX is also used in the study of environmental pollution and in the characterization of mineral bioaccumulated in the tissues. In conclusion, the EDX can be considered as a useful tool in all works that require element determination, endogenous or exogenous, in the tissue, cell or any other sample.

In Situ Detection and Single Cell Quantification of Metal Oxide Nanoparticles Using Nuclear Microprobe Analysis.

Micro-analytical techniques based on chemical element imaging enable the localization and quantification of chemical composition at the cellular level. They offer new possibilities for the characterization of living systems and are particularly appropriate for detecting, localizing and quantifying the presence of metal oxide nanoparticles both in biological specimens and the environment. Indeed, these techniques all meet relevant requirements in terms of (i) sensitivity (from 1 up to 10 µg.g-1 of dry mass), (ii) micrometer range spatial resolution, and (iii) multi-element detection. Given these characteristics, microbeam chemical element imaging can powerfully complement routine imaging techniques such as optical and fluorescence microscopy. This protocol describes how to perform a nuclear microprobe analysis on cultured cells (U2OS) exposed to titanium dioxide nanoparticles. Cells must grow on and be exposed directly in a specially designed sample holder used on the optical microscope and in the nuclear microprobe analysis stages. Plunge-freeze cryogenic fixation of the samples preserves both the cellular organization and the chemical element distribution. Simultaneous nuclear microprobe analysis (scanning transmission ion microscopy, Rutherford backscattering spectrometry and particle induced X-ray emission) performed on the sample provides information about the cellular density, the local distribution of the chemical elements, as well as the cellular content of nanoparticles. There is a growing need for such analytical tools within biology, especially in the emerging context of Nanotoxicology and Nanomedicine for which our comprehension of the interactions between nanoparticles and biological samples must be deepened. In particular, as nuclear microprobe analysis does not require nanoparticles to be labelled, nanoparticle abundances are quantifiable down to the individual cell level in a cell population, independently of their surface state.

Value of immunohistochemical expression of podocalyxin in active lupus nephritis / Valor de la expresión inmunohistoquímica de la podocalixina en la nefritis lúpica activa

Podocalyxin is an electronegative sialoglycoprotein that prevents the podocyte foot process from collapsing. The aim of this study was to detect an association between the glomerular immunohistochemical (IHC) expression of podocalyxin and the degree of podocyte effacement detected by electron microscopy, and to evaluate the role of podocalyxin IHC expression as a novel marker for disease activity in lupus nephritis (LN). Methods: Thirty-two renal biopsies of active lupus nephritis patients were studied. Clinical assessment by the systemic lupus activity measure (SLAM-R) score and laboratory data were included [serum creatinine, 24-h urinary protein, antinuclear antibodies (ANA), anti-double-strand DNA antibodies (anti-dsDNA), C3 and C4]. Light (L/M) and electron microscopic (E/M) examination was conducted. Podocyte loss was evaluated by immunohistochemistry with monoclonal anti-podocalyxin antibodies by means of a semiquantitative score that was graded from 0 to 4+ according to the percentage of glomerular involvement. Results: 22 cases (68.8%) with LN class IV, 6 (18.8%) with class III and 4 (12.5%) with class V. The mean age was (25.41±10.13) years. There was a significant negative correlation between IHC podocalyxin score and LN class, and NIH activity parameters such as leukocyte infiltration, endocapillary proliferation, fibrinoid necrosis and cellular crescent and disease activity index but not chronicity index. There was a highly significant negative correlation between IHC podocalyxin and podocyte effacement by E/M (rs=−0.903, P=0.000), and E/M immune deposits (r=−0.53, P=0.001), and a significant association with degree of proteinuria, ANA and SLAM score (P<0.05). Conclusions: Podocyte loss indicated by podocalyxin immunohistochemical expression reflects the degree of activity and severity of LN and the degree of podocyte effacement by E/M (AU)

La podocalixina es una sialoglicoproteína electronegativa que evita el colapso del proceso podocitario. Nuestro objetivo fue detectar una asociación entre la expresión inmunohistoquímica (IHQ) glomerular de la podocalixina y el grado de borramiento podocitario detectado mediante microscopia electrónica, además de evaluar la función de la expresión IHQ de la podocalixina como un nuevo marcador de la actividad de la enfermedad en la nefritis lúpica (NL). Métodos: Se evaluaron 32 biopsias renales de pacientes con NL activa. Se incluyeron la evaluación clínica mediante la puntuación de la determinación de la actividad del lupus sistémico (systemic lupus activity measure, SLAM-R) y datos analíticos (creatinina sérica, proteína en la orina de 24h, anticuerpos antinucleares [AAN], anticuerpos anti-ADN de doble cadena [anti-ADNdc], C3 y C4). Evaluación mediante microscopio de luz (M/L) y microscopio electrónico (M/E). La evaluación de la pérdida podocitaria se realizó mediante inmunohistoquímica con anticuerpos antipodocalixina monoclonales, por medio de una puntuación semicuantitativa que se clasificó de 0 a 4+ en función del porcentaje de afectación glomerular. Resultados: Encontramos 22 (68,8%) casos con clase IV de NL, 6 (18,8%) con clase III y 4 (12,5%) con clase V. La media de edad fue de 25,41±10,13 años. Se observó una asociación negativa significativa entre la puntuación de la podocalixina en la IHQ con la clase de NL y los parámetros de actividad del NIH, como la infiltración leucocitaria, la proliferación endocapilar, la necrosis fibrinoide y los drepanocitos y el índice de actividad de la enfermedad, pero no el índice de cronicidad. Se observó una correlación negativa muy significativa entre la podocalixina en la IHQ y el borramiento podocitario mediante M/E (rs=−0,903; p=0,000), depósitos inmunes mediante M/E (r=−0,53; p=0,001) y una asociación significativa con el grado de proteinuria, AAN y puntuación en el índice SLAM (p<0,05). Conclusiones: La pérdida podocitaria indicada mediante la expresión IQH de la podocalixina refleja el grado de actividad y la intensidad de la NL, así como el grado de borramiento podocitario mediante M/E (AU)

Backscattered electron imaging and elemental analysis of rapidly frozen plant cells using variable accelerating voltage.

Rapidly frozen rosemary leaves were observed at variable accelerating voltages in a low-vacuum scanning electron microscope equipped with a cryo transfer system. After water was sublimated from the fractured face of the leaf, distinct backscattered electron (BSE) images were obtained depending on the accelerating voltages applied. At 5 kV, surface cell wall structure was observed, whereas at 10 and 15 kV chloroplasts lining the inside of the cell wall and membrane were visualized. With energy dispersive X-ray microanalysis, elemental information corresponding to the BSE images was obtained. Besides visualization of the structures and elemental composition close to the living state, information on layers at different depths from the surface could be detected by varying the accelerating voltage in this system.

Quantitative imaging of Candida utilis and its organelles by soft X-ray Nano-CT.

Soft X-ray microscopy has excellent characteristics for imaging cells and subcellular structures. In this paper, the yeast strain, Candida utilis, was imaged by soft X-ray microscopy and three-dimensional volumes were reconstructed with the SART-TV method. We performed segmentation on the reconstruction in three dimensions and identified several types of subcellular architecture within the specimen cells based on their linear absorption coefficient (LAC) values. Organelles can be identified by the correlation between the soft X-ray LAC values and the subcellular architectures. Quantitative analyses of the volume ratio of organelles to whole cell in different phases were also carried out according to the three-dimensional datasets. With such excellent features, soft X-ray imaging has a great influence in the field of biological cellular and subcellular research.

Medición del contenido del cobre en especímenes biológicos / Measurement of copper content in biological specimens

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Laboratory cryo x-ray microscopy for 3D cell imaging.

Water-window x-ray microscopy allows two- and three-dimensional (2D and 3D) imaging of intact unstained cells in their cryofixed near-native state with unique contrast and high resolution. Present operational biological water-window microscopes are based at synchrotron facilities, which limits their accessibility and integration with complementary methods. Laboratory-source microscopes have had difficulty addressing relevant biological tasks with proper resolution and contrast due to long exposure times and limited up-time. Here we report on laboratory cryo x-ray microscopy with the exposure time, contrast, and reliability to allow for routine high-spatial resolution 3D imaging of intact cells and cell-cell interactions. Stabilization of the laser-plasma source combined with new optics and sample preparation provide high-resolution cell imaging, both in 2D with ten-second exposures and in 3D with twenty-minute tomography. Examples include monitoring of the distribution of carbon-dense vesicles in starving HEK293T cells and imaging the interaction between natural killer cells and target cells.

Biochemistry of malaria parasite infected red blood cells by X-ray microscopy.

Red blood cells infected by the malaria parasite Plasmodium falciparum are correlatively imaged by tomography using soft X-rays as well as by scanning hard nano-X-ray beam to obtain fluorescence maps of various elements such as S and Fe. In this way one can deduce the amount of Fe bound either in hemoglobin or in hemozoin crystals in the digestive vacuole of the malaria parasite as well as determine the hemoglobin concentrations in the cytosols of the red blood cell and of the parasite. Fluorescence map of K shows that in the parasite's schizont stage the K concentration in the red blood cell cytosol is diminished by a factor of seven relative to a pristine red blood cell but the total amount of K in the infected red blood cell is the same as in the pristine red blood cell.

Análisis experimental mediante vibrometría láser doppler en huesos temporales de cadáver fresco de una nueva prótesis de maleovestibulopexia / A new malleostapedotomy prosthesis. Experimental analysis by laser doppler vibrometer in fresh cadaver temporal bones

Introducción y objetivos. Confirmar en temporales frescos de cadáver el comportamiento óptimo teórico (previamente determinado en un modelo computadorizado del oído medio humano) de una nueva prótesis de sustitución osicular total así como objetivar la facilidad de colocación de la misma. Finalmente comprobamos su estabilidad tras ser colocada puesto que el diseño de esta nueva prótesis evita, teóricamente, su movilización o extrusión al anclarse directamente en el mango del martillo. Material y métodos. En el estudio analizamos, mediante vibrometría láser doppler, el comportamiento mecanoacústico de una nueva prótesis de recambio osicular total en el oído medio humano utilizando 10 huesos temporales de cadáver fresco. Resultados. El diseño de la prótesis impide su desplazamiento o extensión y facilita su colocación en el oído medio. La función de transferencia de los temporales a quienes se implantó la nueva prótesis se superpone con la del oído medio intacto antes de la colocación de la prótesis lo que sugiere un comportamiento mecanoacústico óptimo de la misma. Conclusiones. La prótesis de titanio evaluada en este estudio presenta un comportamiento mecanoacústico superponible al del oído medio intacto, lo que se suma a la facilidad de colocación y estabilidad posquirúrgica conviertiéndola en un diseño de prótesis a tener en cuenta ante una reconstrucción osicular total (AU)

Introduction and objectives. One of the problems with total ossicular replacement prostheses is their stability. Prosthesis dislocations and extrusions are common in middle ear surgery. This is due to variations in endo-tympanic pressure as well as design defects. The design of this new prosthesis reduces this problem by being joined directly to the malleus handle. The aim of this study is to confirm adequate acoustic-mechanical behaviour in fresh cadaver middle ear of a new total ossicular replacement prosthesis, designed using the finite elements method. Methods. Using the doppler vibrometer laser, we analysed the acoustic-mechanical behaviour of a new total ossicular replacement prosthesis in the human middle ear using 10 temporal bones from fresh cadavers. Results. The transfer function of the ears in which we implanted the new prosthesis was superimposed over the non-manipulated ear. This suggests optimum acoustic-mechanical behaviour. Conclusions. The titanium prosthesis analysed in this study demonstrated optimum acoustic-mechanical behaviour. Together with its ease of implantation and post-surgical stability, these factors make it a prosthesis to be kept in mind in ossicular reconstruction (AU)

Evaluation of the infection process by Lecanicillium fungicola in Agaricus bisporus by scanning electron microscopy / Evaluación del proceso de infección por Lecanicillium fungicola en Agaricus bisporus por microscopia electrónica de barrido

Background. Lecanicillium fungicola causes dry bubble disease in Agaricus bisporus mushrooms leading to significant economic losses in commercial production. Aims. To monitor the infection process of L. fungicola in Brazilian strains of A. bisporus. Methods. The interaction between the mycelium of L. fungicola (LF.1) and three strains of A. bisporus (ABI 7, ABI 11/14 and ABI 11/21) was studied. Electron microscopy and X-ray microanalyses of vegetative growth and basidiocarp infection were evaluated. Results. Micrographs show that the vegetative mycelium of the Brazilian strains of A. bisporus is not infected by the parasite. The images show that the pathogen can interlace the hyphae of A. bisporus without causing damage, which contributes to the presence of L. fungicola during the substrate colonization, allowing their presence during primordial formation of A. bisporus. In the basidiocarp, germ tubes form within 16h of infection with L. fungicola and the beginning of penetration takes place within 18h, both without the formation of specialized structures. Conclusions. Scanning electron microscopy enabled the process of colonization and reproduction to be observed within the formation of phialides, conidiophores and verticils of L. fungicola. The formation of calcium oxalate crystals by the pathogen was also visible using the X-ray microanalysis, both at the hyphae in the Petri plate and at basidiocarp infection site (AU)

Antecedentes. Lecanicillium fungicola es el agente causal de la enfermedad de la mole seca en Agaricus bisporus, responsable de importantes pérdidas económicas en la producción comercial de esta seta. Objetivos. Comprobar el proceso de infección de L. fungicola en cepas brasileñas de A. bisporus. Métodos. Se estudió la interacción entre el micelio de L. fungicola (LF.1) y tres cepas de A. bisporus (ABI 7, ABI 11/14 y ABI 11/21). Se evaluaron mediante microscopia electrónica y microanálisis de rayos X el crecimiento vegetativo y la infección de los basidiocarpos. Resultados. Las micrografías muestran que el micelio vegetativo de las cepas brasileñas de A. bisporus no resultó afectado por la infección del parásito. Las imágenes muestran también cómo el agente patógeno puede entrelazar las hifas de A. bisporus sin causar daños, lo que contribuye a la perpetuación de L. fungicola durante la colonización del sustrato y durante la formación de los primordios de A. bisporus. En el basidiocarpo, los tubos germinales se forman después de 16h de la infección con L. fungicola y el comienzo de la penetración tiene lugar tras 18h, sin formación de estructuras especializadas. Conclusiones. La microscopia electrónica permite observar el proceso de colonización y reproducción con la formación de fiálides, conidióforos y verticilos de L. fungicola. La formación de cristales de oxalato de calcio por parte del agente patógeno también fue visible mediante el microanálisis por rayos X, tanto en la infección de las hifas en placa de Petri como en la de los basidiocarpos (AU)

Actualización en el carcinoma de células de Merkel: Epidemiología, etiopatogenia, clínica, diagnóstico y estadificación / Update on Merkel cell carcinoma: epidemiology, etiopathogenesis, clinical features, diagnosis, and staging

El carcinoma de células de Merkel (CCM) es un tumor poco frecuente, con un curso evolutivo muy agresivo, que con frecuencia origina recidivas locorregionales y metástasis. Asienta predominantemente en zonas fotoexpuestas en pacientes ancianos. Su incidencia se ha cuadriplicado en las últimas décadas debido al envejecimiento de la población y a un mayor diagnóstico gracias al uso de técnicas inmunohistoquímicas. La patogénesis del CCM no está clara, pero la radiación ultravioleta, la inmunosupresión y la presencia del poliomavirus MCPyV en el genoma del tumor parecen desempeñar un papel fundamental en el desarrollo de esta neoplasia. El objetivo de este artículo es realizar una revisión actualizada sobre los diferentes aspectos de la epidemiología, la etiopatogenia y la clínica del CCM. A su vez, detallamos los aspectos histológicos e inmunohistoquímicos necesarios para su diagnóstico y revisamos la estadificación por su importante trascendencia en el pronóstico de estos pacientes

Merkel cell carcinoma (MCC) is a rare, highly aggressive tumor, and local or regional disease recurrence is common, as is metastasis. MCC usually develops in sun-exposed skin in patients of advanced age. Its incidence has risen 4-fold in recent decades as the population has aged and immunohistochemical techniques have led to more diagnoses. The pathogenesis of MCC remains unclear but UV radiation, immunosuppression, and the presence of Merkel cell polyomavirus in the tumor genome seem to play key roles. This review seeks to update our understanding of the epidemiology, etiology, pathogenesis, and clinical features of MCC. We also review histologic and immunohistochemical features required for diagnosis. MCC staging is discussed, given its great importance in establishing a prognosis for these patients

Quantitative x-ray microanalysis of model biological samples in the SEM using remote standards and the XPP analytical model.

It is shown that accurate x-ray microanalysis of frozen-hydrated and dry organic compounds, such as model biological samples, is possible with a silicon drift detector in combination with XPP (exponential model of Pouchou and Pichoir matrix correction) software using 'remote standards'. This type of analysis is also referred to as 'standardless analysis'. Analyses from selected areas or elemental images (maps) were identical. Improvements in x-ray microanalytical hardware and software, together with developments in cryotechniques, have made the quantitative analysis of cryoplaned frozen-hydrated biological samples in the scanning electron microscope a much simpler procedure. The increased effectiveness of pulse pile-up rejection renders the analysis of Na, with ultrathin window detectors, in the presence of very high concentrations of O, from ice, more accurate. The accurate analysis of Ca (2 mmol kg-1 ) in the presence of high concentrations of K is possible. Careful sublimation of surface frost from frozen-hydrated samples resulted in a small increase in analysed elemental concentrations. A more prolonged sublimation from the same resurfaced sample and other similar samples resulted in higher element concentrations.