Soil erosion and its control in Chile - An overview

La erosión puede deberse a causas naturales, erosión geológica o acelerada. Esta última se induce con la actividad antrópica y los agentes primarios agua y viento, es la forma de degradación más severa del suelo. La degradación del suelo precede a la erosión acelerada, como la compactación, disminución del contenido de materia orgánica, perdida de la estructura de suelo, pobre drenaje interno y problemas asociados a la acidificación del suelo. La erosión puede ser controlada conservando la cobertura protectora vegetal, con la creación de barreras contra los agentes erosivos y modificaciones en el paisaje que permiten controlar el monto y la tasa de escorrentía superficial. Las rotaciones culturales bien planificadas aumentan la calidad del suelo y reducen la erosión. Para lograr un control efectivo sobre la erosión, es necesario mejorar la calidad de la estructura mediante manejos culturales que incluyen cultivos mejorados y con retornos de materia orgánica en forma de residuos de cosecha y guanos, y prácticas de laboreo que no dañan a la estructura. Una labranza conservadora del suelo mejora su calidad al incrementar los niveles en materia orgánica, mejorando la estructura, aireación e infiltración. Las siembras y labores del suelo que se realizan en curva de nivel también reducen la perdida del suelo.Accelerate erosion in Chile is a consequence from land use that degrade soil such as compaction, loss of organic matter and soil structure. The erosion is favored by the very hilly landscape of the country that increases erosivity index and the high erodibility given by an elevated annual rate of rainfall with irr egular distribution . Several experiences have demonstrated that adequate crop management and crop rotations can minimize erosion. The most effective control is achieved conserving and improving soil structure with management systems that include regular use of soil- improving crops, return of crop residues and tillage practices, thus avoiding unnecessary breakdown soil or compacted soil structure. Conservation tillage increased organic matter levels improving stabile soil structure, aeration and infiltration

Blockade of insulin-like growth factors increases efficacy of paclitaxel in metastatic breast cancer

Breast cancer remains the leading cause of cancer death in women owing to metastasis and the development of resistance to established therapies. Macrophages are the most abundant immune cells in the breast tumor microenvironment and can both inhibit and support cancer progression. Thus, gaining a better understanding of how macrophages support cancer could lead to the development of more effective therapies. In this study, we find that breast cancer-associated macrophages express high levels of insulin-like growth factors 1 and 2 (IGFs) and are the main source of IGFs within both primary and metastatic tumors. In total, 75% of breast cancer patients show activation of insulin/IGF-1 receptor signaling and this correlates with increased macrophage infiltration and advanced tumor stage. In patients with invasive breast cancer, activation of Insulin/IGF-1 receptors increased to 87%. Blocking IGF in combination with paclitaxel, a chemotherapeutic agent commonly used to treat breast cancer, showed a significant reduction in tumor cell proliferation and lung metastasis in pre-clinical breast cancer models compared to paclitaxel monotherapy. Our findings provide the rationale for further developing the combination of paclitaxel with IGF blockers for the treatment of invasive breast cancer, and Insulin/IGF1R activation and IGF+ stroma cells as potential biomarker candidates for further evaluation

Effects of FVB/NJ and C57Bl/6J strain backgrounds on mammary tumor phenotype in inducible nitric oxide synthase deficient mice

The ability to genetically manipulate mice has led to rapid progress in our understanding of the roles of different gene products in human disease. Transgenic mice have often been created in the FVB/NJ (FVB) strain due to its high fecundity, while gene-targeted mice have been developed in the 129/SvJ-C57Bl/6J strains due to the capacity of 129/SvJ embryonic stem cells to facilitate germline transmission. Gene-targeted mice are commonly backcrossed into the C57Bl/6J (B6) background for comparison with existing data. Genetic modifiers have been shown to modulate mammary tumor latency in mouse models of breast cancer and it is commonly known that the FVB strain is susceptible to mammary tumors while the B6 strain is more resistant. Since gene-targeted mice in the B6 background are frequently bred into the polyomavirus middle T (PyMT) mouse model of breast cancer in the FVB strain, we have sought to understand the impact of the different genetic backgrounds on the resulting phenotype. We bred mice deficient in the inducible nitric oxide synthase (iNOS) until they were congenic in the PyMT model in the FVB and B6 strains. Our results reveal that the large difference in mean tumor latencies in the two backgrounds of 53 and 92 days respectively affect the ability to discern smaller differences in latency due to the Nos2 genetic mutation. Furthermore, the longer latency in the B6 strain enables a more detailed analysis of tumor formation indicating that individual tumor development is not stoichastic, but is initiated in the #1 glands and proceeds in early and late phases. NO production affects tumors that develop early suggesting an association of iNOS-induced NO with a more aggressive tumor phenotype, consistent with human clinical data positively correlating iNOS expression with breast cancer progression. An examination of lung metastases, which are significantly reduced in PyMT/iNOS(−/−) mice compared with PyMT/iNOS(+/+) mice only in the B6 background, is concordant with these findings. Our data suggest that PyMT in the B6 background provides a useful model for the study of inflammation-induced breast cancer

Blockade of insulin-like growth factors increases efficacy of paclitaxel in metastatic breast cancer.

Breast cancer remains the leading cause of cancer death in women owing to metastasis and the development of resistance to established therapies. Macrophages are the most abundant immune cells in the breast tumor microenvironment and can both inhibit and support cancer progression. Thus, gaining a better understanding of how macrophages support cancer could lead to the development of more effective therapies. In this study, we find that breast cancer-associated macrophages express high levels of insulin-like growth factors 1 and 2 (IGFs) and are the main source of IGFs within both primary and metastatic tumors. In total, 75% of breast cancer patients show activation of insulin/IGF-1 receptor signaling and this correlates with increased macrophage infiltration and advanced tumor stage. In patients with invasive breast cancer, activation of Insulin/IGF-1 receptors increased to 87%. Blocking IGF in combination with paclitaxel, a chemotherapeutic agent commonly used to treat breast cancer, showed a significant reduction in tumor cell proliferation and lung metastasis in pre-clinical breast cancer models compared to paclitaxel monotherapy. Our findings provide the rationale for further developing the combination of paclitaxel with IGF blockers for the treatment of invasive breast cancer, and Insulin/IGF1R activation and IGF+ stroma cells as potential biomarker candidates for further evaluation

Contributions of thrombin targets to tissue factor-dependent metastasis in hyperthrombotic mice

Tumor cell tissue factor (TF)-initiated coagulation supports hematogenous metastasis by fibrin formation, platelet activation, and monocyte/macrophage recruitment. Recent studies identified host anticoagulant mechanisms as a major impediment for successful hematogenous tumor cell metastasis

Gene Classification Based on Amino Acid Motifs and Residues: The DLX (distal-less) Test Case

BACKGROUND:Comparative studies using hundreds of sequences can give a detailed picture of the evolution of a given gene family. Nevertheless, retrieving only the sequences of interest from public databases can be difficult, in particular, when working with highly divergent sequences. The difficulty increases substantially when one wants to include in the study sequences from many (or less well studied) species whose genomes are non-annotated or incompletely annotated. METHODOLOGY/PRINCIPAL FINDINGS:In this work we evaluate the usefulness of different approaches of gene retrieval and classification, using the distal-less (DLX) gene family as a test case. Furthermore, we evaluate whether the use of a large number of gene sequences from a wide range of animal species, the use of multiple alternative alignments, and the use of amino acids aligned with high confidence only, is enough to recover the accepted DLX evolutionary history. CONCLUSIONS/SIGNIFICANCE:The canonical DLX homeobox gene sequence here derived, together with the characteristic amino acid variants here identified in the DLX homeodomain region, can be used to retrieve and classify DLX genes in a simple and efficient way. A program is made available that allows the easy retrieval of synteny information that can be used to classify gene sequences. Maximum likelihood trees using hundreds of sequences can be used for gene identification. Nevertheless, for the DLX case, the proposed DLX evolutionary is not recovered even when multiple alignment algorithms are used

Diseases of the salivary glands in infants and adolescents

<p>Abstract</p> <p>Background</p> <p>Diseases of the salivary glands are rare in infants and children (with the exception of diseases such as parotitis epidemica and cytomegaly) and the therapeutic regimen differs from that in adults. It is therefore all the more important to gain exact and extensive insight into general and special aspects of pathological changes of the salivary glands in these age groups. Etiology and pathogenesis of these entities is still not yet fully known for the age group in question so that general rules for treatment, based on clinical experience, cannot be given, particularly in view of the small number of cases of the different diseases. Swellings of the salivary glands may be caused by acute and chronic inflammatory processes, by autoimmune diseases, by duct translocation due to sialolithiasis, and by tumors of varying dignity. Clinical examination and diagnosis has also to differentiate between salivary gland cysts and inflammation or tumors.</p> <p>Conclusion</p> <p>Salivary gland diseases are rare in childhood and adolescence. Their pattern of incidence differs very much from that of adults. Acute and chronic sialadenitis not responding to conservative treatment requires an appropriate surgical approach. The rareness of salivary gland tumors is particularly true for the malignant parotid tumors which are more frequent in juvenile patients, a fact that has to be considered in diagnosis and therapy.</p

Lrp4 Modulates Extracellular Integration of Cell Signaling Pathways in Development

The extent to which cell signaling is integrated outside the cell is not currently appreciated. We show that a member of the low-density receptor-related protein family, Lrp4 modulates and integrates Bmp and canonical Wnt signalling during tooth morphogenesis by binding the secreted Bmp antagonist protein Wise. Mouse mutants of Lrp4 and Wise exhibit identical tooth phenotypes that include supernumerary incisors and molars, and fused molars. We propose that the Lrp4/Wise interaction acts as an extracellular integrator of epithelial-mesenchymal cell signaling. Wise, secreted from mesenchyme cells binds to BMP's and also to Lrp4 that is expressed on epithelial cells. This binding then results in the modulation of Wnt activity in the epithelial cells. Thus in this context Wise acts as an extracellular signaling molecule linking two signaling pathways. We further show that a downstream mediator of this integration is the Shh signaling pathway

Minimally invasive application of botulinum toxin A in patients with idiopathic rhinitis

<p>Abstract</p> <p>Background</p> <p>Nasal hypersecretion due to idiopathic rhinitis can often not be treated sufficiently by conventional medication. Botulinum toxin A (BTA) has been injected into the nasal mucosa in patients with nasal hypersecretion with a reduction of rhinorrhea lasting for about 4 to 8 weeks. Since the nasal mucosa is well supplied with glands and vessels, the aim of this study was to find out if the distribution of BTA in the nasal mucosa and a reduction of nasal hypersecretion can also be reached by a minimally invasive application by sponges without an injection.</p> <p>Methods</p> <p>Patients were randomly divided into two groups. The effect of BTA (group A, C, D) or saline as placebo (group B) was investigated in 20 patients with idiopathic rhinitis by applying it with a sponge soaked with BTA (40 units each nostril) or saline. Subgroups C and D contained these patients of group A and B who did not improve in symptoms one week after the original treatment (either BTA or saline) who then received the alternative medication. Changes of symptoms (rhinorrhea, nasal obstruction) were scored by the patients in a four point scale and counted (consumption of tissues, sneezing) in a diary. The patients were followed up weeks 1, 2, 4, 8 and 12.</p> <p>Results</p> <p>There was a clear reduction of the amount of secretion in group A compared to group B, C and D. This did not correlate with the tissue consumption, which was comparably reduced in group A and B, but reduced less in group C and D. Sneezing was clearly reduced in group A but comparably unchanged in group B and C and increased in group D. Nasal congestion remained unchanged.</p> <p>Conclusion</p> <p>In some patients with therapy-resistant idiopathic rhinitis BTA applied with a sponge is a long-lasting and minimal invasive therapy to reduce nasal hypersecretion.</p