The architectural design of urban space and its influence in the communities of parasites in two areas of Buenos Aires City with different circulation dynamic of companion animals

Las excretas de mascotas constituyen un factor de riesgo para la transmisión urbana de zoonosis parasitarias. La abundancia de excretas depende del número de animales, de la posibilidad de acceso y el uso de distintos espacios urbanos. En plazas y parques públicos los animales deambulan acompañados por personas; en parques y jardines privados, el acceso y circulación está restringido a aquellos animales cuyos dueños habitan en el predio. El objetivo de este trabajo fue determinar si las barreras artificiales antropogénicas, condicionantes del tránsito de animales, limitan la dispersión de enteroparásitos. En áreas con desplazamiento restringido (BPLA) y con circulación libre (PP), fueron colectadas heces (BPLA: n=39; PP: n=50) y suelo (BPLA: n=20; PP: n=20) y procesadas por métodos convencionales. La frecuencia de especies en cada ambiente y para cada tipo de muestra fue comparada por el test de Diferencia de Proporciones. Las diferencias entre el número de especies parasitarias en cada matriz ambiental fueron establecidas con el test de Mann-Whitney (alfa=0,05). La similitud de las comunidades fue determinada con el Índice cualitativo de Sorensen (ICS). La proporción de muestras positivas en BPLA fue mayor que en PP (Tierra: 1,0 vs. 0,70; p<0,05 y Heces 0,56 vs. 0,32; p<0,05). En suelo, no se detectaron helmintos; el número de especies por unidad de muestreo fue mayor en BPLA que en PP (Mann-Whitney: U=300; p<0,01) así como la frecuencia relativa de Cryptosporidium sp. (1,0 vs. 0,56; p=0,0006); la riqueza de especies fue similar (ICS=0,8). El confinamiento de animales domésticos urbanos y la restricción de su desplazamiento al espacio verde cercado de su peridomicilio determinan el grado de contaminación fecal del suelo, agravado por el mal hábito higiénico de los propietarios. En estas situaciones, el suelo concentraría algunas formas infectivas y facilitaría su transmisión, realimentando los ciclos de infección y reinfección parasitaria.The presence of canine and feline faeces is a known risk factor for the transmission of zoonotic parasitoses. Their dispersion is tightly linked to the mobility of its hosts and their capability of contaminating such environments with faecal matter, and the latter will be clearly influenced by the ability of entering and exiting such area. Different uses of the urban space where the hosts inhabit may affect precisely that aptitude. It was hypothesized that certain artificial barriers created by urban settings, such as walls and fences, could limit the dispersion of parasitoses as they would limit the mobility of their hosts. The objective of this study was to determine if there were any differences between the communities of intestinal parasites found in excreta and soil samples within two bordering areas, one with restricted circulation (BPLA) and another one without such restrictions (PP). Faecal (BPLA: n=39; PP: n=50) and soil (BPLA: n=20; PP: n=20) samples were collected, processed according to the Willis and the Bacigalupo–Rivero techniques, and diagnosed by optical microscopy of fresh smears, lugol, Kinyoun and modified Ziehl-Neelsen stain. In order to establish statistical differences between the frequencies for all parasite species found in either environment for each sample type, the two populations‟ Difference in Proportions Test was performed. To assess communities‟ similarity, the Sorensen index was utilized and to determine if there were differences between the number of different species per sample the Mann–Whitney test was applied. Statistical differences were found in the total frequency of faeces and soil samples positive for any parasitic form, being higher in BPLA in both cases (p&lt;0, 05). On the other hand, there were no statistical differences for any particular species in any of the two sample types studied, with the exception of Cryptosporidium sp. that proved to be higher in BPLA soil samples (p&lt;0,01). The Sorensen index to compare the similarity among faecal and soil communities found in each urban environment were both 0,8. However, the Mann-Whitney test showed that there were a statistically major number of species per soil sample in BPLA than in PP. When taking these results into consideration, it could be inferred that urban architectonic barriers restricting pet displacements tend toward a raise of faecal contamination, thus increasing the chance of transmission of the studied pathogens, and accelerating cycles of transmission and reinfection.En "Documentos relacionados" se encuentra el link para acceder a la versión en español del artículo.Asociación Parasitológica Argentin

Plastic changes in the spinal cord in motor neuron disease.

In the present paper, we analyze the cell number within lamina X at the end stage of disease in a G93A mouse model of ALS; the effects induced by lithium; the stem-cell like phenotype of lamina X cells during ALS; the differentiation of these cells towards either a glial or neuronal phenotype. In summary we found that G93A mouse model of ALS produces an increase in lamina X cells which is further augmented by lithium administration. In the absence of lithium these nestin positive stem-like cells preferentially differentiate into glia (GFAP positive), while in the presence of lithium these cells differentiate towards a neuronlike phenotype (III-tubulin, NeuN, and calbindin-D28K positive). These effects of lithium are observed concomitantly with attenuation in disease progression and are reminiscent of neurogenetic effects induced by lithiumin the subependymal ventricular zone of the hippocampus

3D Bioprinted Human Skeletal Muscle Constructs for Muscle Function Restoration

A bioengineered skeletal muscle tissue as an alternative for autologous tissue flaps, which mimics the structural and functional characteristics of the native tissue, is needed for reconstructive surgery. Rapid progress in the cell-based tissue engineering principle has enabled in vitro creation of cellularized muscle-like constructs; however, the current fabrication methods are still limited to build a three-dimensional (3D) muscle construct with a highly viable, organized cellular structure with the potential for a future human trial. Here, we applied 3D bioprinting strategy to fabricate an implantable, bioengineered skeletal muscle tissue composed of human primary muscle progenitor cells (hMPCs). The bioprinted skeletal muscle tissue showed a highly organized multi-layered muscle bundle made by viable, densely packed, and aligned myofiber-like structures. Our in vivo study presented that the bioprinted muscle constructs reached 82% of functional recovery in a rodent model of tibialis anterior (TA) muscle defect at 8 weeks of post-implantation. In addition, histological and immunohistological examinations indicated that the bioprinted muscle constructs were well integrated with host vascular and neural networks. We demonstrated the potential of the use of the 3D bioprinted skeletal muscle with a spatially organized structure that can reconstruct the extensive muscle defects

Computational Modelling of Tissue-Engineered Cartilage Constructs

Cartilage is a fundamental tissue to ensure proper motion between bones and damping of mechanical loads. This tissue often suffers damage and has limited healing capacity due to its avascularity. In order to replace surgery and replacement of joints by metal implants, tissue engineered cartilage is seen as an attractive alternative. These tissues are obtained by seeding chondrocytes or mesenchymal stem cells in scaffolds and are given certain stimuli to improve establishment of mechanical properties similar to the native cartilage. However, tissues with ideal mechanical properties were not obtained yet. Computational models of tissue engineered cartilage growth and remodelling are invaluable to interpret and predict the effects of experimental designs. The current model contribution in the field will be presented in this chapter, with a focus on the response to mechanical stimulation, and the development of fully coupled modelling approaches incorporating simultaneously solute transport and uptake, cell growth, production of extracellular matrix and remodelling of mechanical properties.publishe

Flow cytometric cell cycle analysis of muscle precursor cells cultured within 3D scaffolds in a perfusion bioreactor

It has been widely demonstrated that perfusion bioreactors improve in vitro three\u2010dimensional (3D) cultures in terms of high cell density and uniformity of cell distribution; however, the studies reported in literature were primarily based on qualitative analysis (histology, immunofluorescent staining) or on quantitative data averaged on the whole population (DNA assay, PCR). Studies on the behavior, in terms of cell cycle, of a cell population growing in 3D scaffolds in static or dynamic conditions are still absent. In this work, a perfusion bioreactor suitable to culture C2C12 muscle precursor cells within 3D porous collagen scaffolds was designed and developed and a method based on flowcytometric analyses for analyzing the cell cycle in the cell population was established. Cells were extracted by enzymatic digestion of the collagen scaffolds after 4, 7, and 10 days of culture, and flow cytometric live/dead and cell cycle analyses were performed with Propidium Iodide. A live/dead assay was used for validating the method for cell extraction and staining. Moreover, to investigate spatial heterogeneity of the cell population under perfusion conditions, two stacked scaffolds in the 3D domain, of which only the upstream layer was seeded, were analyzed separately. All results were compared with those obtained from static 3D cultures. The live/dead assay revealed the presence of less than 20% of dead cells, which did not affect the cell cycle analysis. Cell cycle analyses highlighted the increment of cell fractions in proliferating phases (S/G2/M) owing to medium perfusion in long\u2010term cultures. After 7\u201310 days, the percentage of proliferating cells was 8\u201312% for dynamic cultures and 3\u20135% for the static controls. A higher fraction of proliferating cells was detected in the downstream scaffold. From a general perspective, this method provided data with a small standard deviation and detected the differences between static and dynamic cultures and between upper and lower scaffolds. Our methodology can be extended to other cell types to investigate the influence of 3D culture conditions on the expression of other relevant cell markers

Lamina X of the spinal cord in motor neuron disease

Lamina X of spinal cord in motor neuron diseas