51 research outputs found
Analyse de la qualité physico-chimique des eaux souterraines de la communauté des Mzamza, au voisinage des eaux usées
Analyze of the physicochemical quality of Mzamza’s communityof ground waters, around waste waters In the Mzamza’s community, characterized by an important agricultural potentiality especially in the perimeters irrigated by domestic and industrial water, ground waters are prone to several possibilities of contamination. However in this zone, the ground waters are considered as an important resource used to drink water and irrigation. The objective of this study is, on the one hand, to try to evaluate the impact of the wastes water’s re-use on the physicochemical quality of wells’water in the zone of study and, on the other hand, to determine its quality refering to the standards of potability or irrigation. The results obtained showed that the concentrations of the elements considered (principal pollutants and indicators of pollution) are high in waste waters and ground waters.The ratio of adsorption of sodium (SAR) enabled us to qualifie groundwaters intended to the irrigation, and the causes of salinisation of the soil when using it in this domain.Several determining factors were highlighted in the contamination of ground waters by these pollutants, namely: the contribution of nitrogenized fertilizers, the nature of soil, the lithology, the permeability of the aquifer and the outdistances well compared to the sources of pollution which are waste waters
Study of the chemical composition of argan oil according to the shape of the fruit
The aim of this study was to investigate the effect of phenotypic diversity of argan fruit with different morphological characteristics (fusiform, oval, apiculate and spherical) on fat and protein content, inflexibility and fat chemical composition, oil acids and sterols. To investigate the links of argan fruit shape with the chemical composition of argan oil, with the help of native communities, 4 different fruit shapes (fusiform, apiculate, spherical and oval) were selected, which were harvested from the same place (Tamanar) in Essaouira province (South Plain region, Western Morocco). After harvesting the fruit of the argan tree, 100 samples were taken from each form. They were crushed to destroy the core. After extraction of hexane with Soxhlet, fat content, protein level, unsaponifiable content, composition of fatty acids and sterols in fat were determined. The results showed that the oval shape is the best shape of argan fruit because their kernels contain more than 50% fat and a higher percentage of unsaponifiables. The results on fatty acids and sterols showed that argan oil contained 80% of unsaturated fatty acids. The results also showed that the main products of the sterol composition in argan oil were schottenol (or Δ-7-stigmasterol) (42.8 and 46.4%) and spinasterol (39.8 and 45.6%). The study of the chemical composition showed that there was no correlation between the shape of the fruit of the argan tree and the composition of fatty acids. Depending on the shape of the argan fruit, fatty acids and sterols were not only related to the shape but also to the nature of the soil and its altitude, longitude and distance from the sea
Evaluating the cost and gain from genetic resistance to Hessian fly (Mayetiola destructor (say)) in durum wheat in Morocco using recombinant inbred lines
Durum wheat (Triticum turgidum L. var. durum) is an important food crop in the Mediterranean region. Hessian fly is the most important insect pest of wheat in the dry land areas in Morocco. Breeding wheat for genetic resistance to pests is the most sustainable control strategy because genetic resistance brings yield advantage under pest attack. However, there are fears that this resistance could have its price in terms of yield potential under pest free situation. The objective of this study was to quantify the yield gains in the presence of H. fly and verify the assumption of resistance cost in the absence of the pest. One hundred and eighty recombinant inbred lines of durum wheat (RILs) derived from the crosses (CI115 / Bzaiz-AHF/CM829/Cando -H25) segregated for Hessian fly resistance and adapted to dry areas were planted in two experimental domains of INRA, differing in Hessian fly infestation levels (Sidi El Aidi and Jemaa-Shaim) in the 2012-2013 season. Plants were evaluated for agronomic and phenological traits as well as for yield components. The data indicated that under severe H. fly attacks, the yield losses avoided by resistant lines may reach 100% and that under pest free situation, the mean values of each parameter measured are similar between resistant and susceptible groups of lines. These results indicated that resistance had no negative effect on genetic potential of studied characters in this case study. In addition, the phenotypic correlations between different traits are similar between groups under differing situations and this confirms the above results. The conclusion is that incorporating genetic resistance to Hessian fly has a positive effect on phenological and agro-morphologic traits, as well as on yield and yield components under H. fly attack, and has no negative effect on these parameters in a fly free situation
Xenograft models of head and neck cancers
Head and neck cancers are among the most prevalent tumors in the world. Despite advances in the treatment of head and neck tumors, the survival of patients with these cancers has not markedly improved over the past several decades because of our inability to control and our poor understanding of the regional and distant spread of this disease. One of the factors contributing to our poor understanding may be the lack of reliable animal models of head and neck cancer metastasis. The earliest xenograft models in which human tumor cells were grown in immunosuppressed mice involved subcutaneous implantation of human head and neck cancer cell lines. Subcutaneous xenograft models have been popular because they are easy to establish, easy to manage, and lend themselves to ready quantitation of the tumor burden. More recently, orthotopic xenograft models, in which the tumor cells are implanted in the tumor site of origin, have been used with greater frequency in animal studies of head and neck cancers. Orthotopic xenograft models are advantageous for their ability to mimic local tumor growth and recapitulate the pathways of metastasis seen in human head and neck cancers. In addition, recent innovations in cell labeling techniques and small-animal imaging have enabled investigators to monitor the metastatic process and quantitate the growth and spread of orthopically implanted tumors. This review summarizes the progress in the development of murine xenograft models of head and neck cancers. We then discuss the advantages and disadvantages of each type of xenograft model. We also discuss the potential for these models to help elucidate the mechanisms of regional and distant metastasis, which could improve our ability to treat head and neck cancers
Highly variable response to cytotoxic chemotherapy in carcinoma-associated fibroblasts (CAFs) from lung and breast
<p>Abstract</p> <p>Background</p> <p>Carcinoma-associated fibroblasts (CAFs) can promote carcinogenesis and tumor progression. Only limited data on the response of CAFs to chemotherapy and their potential impact on therapy outcome are available. This study was undertaken to analyze the influence of chemotherapy on carcinoma-associated fibroblasts (CAFs) <it>in vitro </it>and <it>in vivo</it>.</p> <p>Methods</p> <p>The <it>in vivo </it>response of stromal cells to chemotherapy was investigated in 22 neoadjuvant treated breast tumors on tissue sections before and after chemotherapy. Response to chemotherapy was analyzed <it>in vitro </it>in primary cultures of isolated CAFs from 28 human lung and 9 breast cancer tissues. The response was correlated to <it>Mdm2</it>, <it>ERCC1 </it>and <it>TP53 </it>polymorphisms and <it>TP53 </it>mutation status. Additionally, the cytotoxic effects were evaluated in an <it>ex vivo </it>experiment using cultured tissue slices from 16 lung and 17 breast cancer specimens.</p> <p>Results</p> <p>Nine of 22 tumors showed a therapy-dependent reduction of stromal activity. Pathological response of tumor or stroma cells did not correlate with clinical response. Isolated CAFs showed little sensitivity to paclitaxel. In contrast, sensitivity of CAFs to cisplatinum was highly variable with a GI50 ranging from 2.8 to 29.0 ÎĽM which is comparable to the range observed in tumor cell lines. No somatic <it>TP53 </it>mutation was detected in any of the 28 CAFs from lung cancer tissue. In addition, response to cisplatinum was not significantly associated with the genotype of <it>TP53 </it>nor <it>Mdm2 </it>and <it>ERCC1 </it>polymorphisms. However, we observed a non-significant trend towards decreased sensitivity in the presence of <it>TP53 </it>variant genotype. In contrast to the results obtained in isolated cell culture, in tissue slice culture breast cancer CAFs responded to paclitaxel within their microenvironment in the majority of cases (9/14). The opposite was observed in lung cancer tissues: only few CAFs were sensitive to cisplatinum within their microenvironment (2/15) whereas a higher proportion responded to cisplatinum in isolated culture.</p> <p>Conclusion</p> <p>Similar to cancer cells, CAF response to chemotherapy is highly variable. Beside significant individual/intrinsic differences the sensitivity of CAFs seems to depend also on the cancer type as well as the microenvironment.</p
Conditionally Replicating Adenovirus Expressing TIMP2 Increases Survival in a Mouse Model of Disseminated Ovarian Cancer
Ovarian cancer remains difficult to treat mainly due to presentation of the disease at an advanced stage. Conditionally-replicating adenoviruses (CRAds) are promising anti-cancer agents that selectively kill the tumor cells. The present study evaluated the efficacy of a novel CRAd (Ad5/3-CXCR4-TIMP2) containing the CXCR4 promoter for selective viral replication in cancer cells together with TIMP2 as a therapeutic transgene, targeting the matrix metalloproteases (MMPs) in a murine orthotopic model of disseminated ovarian cancer. An orthotopic model of ovarian cancer was established in athymic nude mice by intraperitonal injection of the human ovarian cancer cell line, SKOV3-Luc, expressing luciferase. Upon confirmation of peritoneal dissemination of the cells by non-invasive imaging, mice were randomly divided into four treatment groups: PBS, Ad-ΔE1-TIMP2, Ad5/3-CXCR4, and Ad5/3-CXCR4-TIMP2. All mice were imaged weekly to monitor tumor growth and were sacrificed upon reaching any of the predefined endpoints, including high tumor burden and significant weight loss along with clinical evidence of pain and distress. Survival analysis was performed using the Log-rank test. The median survival for the PBS cohort was 33 days; for Ad-ΔE1-TIMP2, 39 days; for Ad5/3-CXCR4, 52.5 days; and for Ad5/3-CXCR4-TIMP2, 63 days. The TIMP2-armed CRAd delayed tumor growth and significantly increased survival when compared to the unarmed CRAd. This therapeutic effect was confirmed to be mediated through inhibition of MMP9. Results of the in vivo study support the translational potential of Ad5/3-CXCR4-TIMP2 for treatment of human patients with advanced ovarian cancer
The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance
INTRODUCTION
Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic.
RATIONALE
We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs).
RESULTS
Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants.
CONCLUSION
Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century
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