99 research outputs found

    Effect of stage of lactation on the physical and chemical composition of Drâa goat milk

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    Raw milk characterization constitutes a preliminary and an important step to take account in order to obtain an optimal technological valorization. Among other factors, breed, feed and stage of lactation are the most important factors that influenced cheese making and other dairy products valorization. Thus, this study proposes to analyze the physicochemical composition of Drâa goat milk and to study raw milk fluctuations throughout a complete lactation period. The study was carried out in the Experimental Station of Errachidia (Southern Morocco). In this context, sixteen goats were selected and sampled every week during a period of 160 days (average lactation length). A total of 128 samples of raw goat milk were analyzed according to international standards. Analyses were focused to determination of pH, acidity, density, Dry Matter (DM), Solids Non Fat (SNF), ash, fat and Total Nitrogenous Matter (TNM). Average values were about 17.8°D for acidity, 13.3% for Dry Matter, 0.73% for ash, 4.16% for fat and 3.60% for Total Nitrogenous Matter. In general, theses values are largely situated in the upper level of the range suggested by several Moroccan and foreign researchers for other goat species. On the other hand, the evolution of physical and chemical parameters throughout  lactation stages showed that dry matter, fat content and total nitrogenous matter increased significantly throughout the lactation period; the opposite was found for density (p<0.001). No significant (p>0.05) changes were shown for milk acidity and the average found was around 17°D. Content of milk ash increased significantly during the late lactation stage compared to the earliest and the opposite was observed for pH.The results of the  present investigation show that Drâa goat milk is rich with desirable  components like fat and protein for dairy product manufacturers, and that the late lactation stage seems to be the best period to ensure an optimum technological valorization.Key words: Goat, Morocco, milk, physicochemical, lactatio

    Copepod community along the Mediterranean coast of Morocco (Southwestern Alboran Sea) during spring

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    Copepod community along the Mediterranean Moroccan coast was investigated, for the first time, during April 2013. Total abundance varied from 53 to 4557 ind. m-3 and high values were found in coastal waters. Oithona nana and Paracalanus parvus dominated in the entire area and species diversity was decreasing from the West to the East. Hierarchical clustering revealed three groups of stations, depending on their geographic position (western, central and eastern areas). Indicator species analysis pointed out that Clausocalanus furcatus and Gaetanus sp. were significantly associated with Group I, Clausocalanus sp., Centropages sp. and Centropages chierchiae with Group II, whereas Temora longicornis was significantly associated with Group III. Detrended Correspondence Analysis based on the species abundance and environmental variables (temperature, salinity, chlorophyll-a), highlighted a more or less similar setting of stations which was related to salinity and temperature. The presence of three anticyclonic gyres at the northern part of the study area is suggested as the major factor acting on the variability of copepod community along the Mediterranean Moroccan coast

    Dynamic Analysis of an Annular Plate Resting on the Surface of an Elastic Half-Space with Distributive Properties

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    This work gives a semi-analytical approach for the dynamic analysis of a plate of annular shape resting on the surface of an elastic half-space with distributive properties. Such calculations have been associated with significant mathematical challenges, often leading to unrealizable computing processes. Therefore, the dynamic analysis of beams and plates interacting with the surfaces of elastic foundations has to date not been completely solved. To advance this work, the deflections of the plate are determined by the Ritz method, and the displacements of the surface of elastic half-space are determined by studying Green's function. The coupling of these two studies is achieved by a mixed method, which allows determination of reactive forces in the contact zone and, hence, the determination of other physical magnitudes. Natural frequencies, natural shapes, and the dynamic response of a plate due to external harmonic excitation are determined. Validation with a Winkler problem illustrates the distributive property effects on the results of the dynamic analysis

    Prevention of chronic rejection in mouse aortic allografts by combined treatment with CTLA4-Ig and anti-CD40 ligand monoclonal antibody

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    Background. In this study, using a murine model of aortic allotransplantation, the role of blockade of signaling through CD28/B7 and CD40/CD40 ligand costimulatory pathways in the evolvement of posttransplant vasculopathy was examined. Methods. Aortic allografts were transplanted across C57BL/10J (H2b)→C3H (H2(k)) strain combinations. Transient or more stable blockade of second signaling was achieved by either a single injection or multiple injections of CTLA4-Ig fusion protein (200 μg/dose i.p.) and/or anti-CD40 ligand (CD40L) monoclonal antibody (250 μg i.m.). At day 30 after transplantation, the grafts were harvested for histopathological and immunohistochemical examination. Results. Similar to allografts of untreated animals, aortic allografts obtained from recipients treated with either CTLA4-Ig or anti-CD40L monoclonal antibody alone exhibited marked narrowing of the lumen primarily due to concentric intimal thickening caused by proliferation of α-smooth muscle actin-positive cells. Contemporaneous treatment, however, with either a single injection or multiple injections of CTLA4-Ig and anti-CD40L monoclonal antibody resulted in marked diminution of intimal thickening. Interestingly, concurrent prolonged inhibition of CD28/B7 and CD40/ CD40L pathways resulted in complete abrogation of the development of posttransplant arteriopathy. Conclusion. These data suggest that a more stable disruption of signaling through costimulatory pathways may be required to obviate the development of posttransplant vasculopathy

    Abrogation of chronic rejection in a murine model of aortic allotransplantation by prior induction of donor-specific tolerance

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    Aortic allotransplantation in mice has been well established as a model of choice to study the evolvement of chronic rejection, the etiopathology of which is believed to be that of immune origin. This has prompted the postulation that prior induction of donor-specific tolerance would attenuate or abrogate the underlying events that culminate in posttransplant arteriosclerosis. To study the effects of donor-specific tolerance on chronic rejection, we performed orthotopic liver transplantation without immunosuppression in mice 30 days before aortic allotransplantation across C57Bl/10J (H2b)→C3H (H2(k)) strain combinations (group III). Aortic allografting in syngeneic (group I; C3H→C3H) and allogeneic (group II, C57Bl/10J→C3H) animals served as controls. No morphological changes were evidenced in the transplanted aortas in group I animals. Contrarily, aortic allografts in group H animals underwent a self-limiting acute cellular rejection, which resolved completely and was succeeded by day 30 after transplantation by histopathological changes pathognomonic of chronic rejection. There was evidence for diffuse myointimal thickening, progressive concentric luminal narrowing, and patchy destruction of internal elastic membranes resulting in massive vascular obliteration by day 120 after transplantation. It was of interest that no arteriosclerotic changes were observed for the duration of follow-up (up to 120 days after transplantation) in transplanted aortas (liver donor-type) harvested from animals in group III. However, vasculopathy was prominent in third-party aortic grafts transplanted into tolerant recipients. Taken together, these data suggest that prior induction of tolerance abrogates the development of chronic rejection; this protection seems to be donor specific

    Evidence for the presence of multilineage chimerism and progenitors of donor dendritic cells in the peripheral blood of bone marrow-augmented organ transplant recipients

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    We have postulated that the donor leukocyte microchimerism plays a seminal role in the acceptance of allografts by inducing and perpetuating variable degree of donor-specific nonreactivity in long-surviving organ recipients. Limited information is available, however, concerning the phenotype and function of these chimeric cells in humans. The unequivocal presence of donor dendritic cells (DCs), a prominent lineage in the microchimerism observed in rodents and clinical organ recipients, was difficult to demonstrate in bone marrow (BM)-augmented organ transplant recipients. This enigma was resolved by the recent description of a method for propagating circulating human DCs from their progenitors by culture in a medium enriched with granulocyte-macrophage colony-stimulating factor and interleukin 4, a condition known to inhibit outgrowth of monocytes, thus providing a selective growth advantage to committed progenitors of the myeloid lineage. Cells from BM-augmented organ recipients and normal control subjects harvested from 12- to 14-day cultures exhibited dendritic morphology and potent allostimulatory capacity. Using appropriate primers, the presence of donor DNA was verified by polymerase chain reaction within the lineage(null)/class II(bright) sorted DC. Phenotypic analysis of cultured DCs from BM-augmented patients, unlike that of controls, exhibited a marked down- regulation of B7-1 (CD80) while retaining normal levels of expression of B7- 2 (CD86) cell surface molecules. The presence of donor DNA was also confirmed by polymerase chain reaction in individually sorted lineage+ (T, B, and NK) cells and macrophages, suggesting that the chimerism in BM-augmented patients is multilineage. The presence of progenitors of donor DCs in the peripheral blood of BM-augmented patients further substantiates the already convincing evidence of stem cell engraftment

    Placental transfer of the polybrominated diphenyl ethers BDE-47, BDE-99 and BDE-209 in a human placenta perfusion system: an experimental study

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    <p>Abstract</p> <p>Background</p> <p>Polybrominated diphenyl ethers (PBDEs) have been widely used as flame retardants in consumer products. PBDEs may affect thyroid hormone homeostasis, which can result in irreversible damage of cognitive performance, motor skills and altered behaviour. Thus, in utero exposure is of very high concern due to critical windows in fetal development.</p> <p>Methods</p> <p>A human ex vivo placenta perfusion system was used to study the kinetics and extent of the placental transfer of BDE-47, BDE-99 and BDE-209 during four-hour perfusions. The PBDEs were added to the maternal circulation and monitored in the maternal and fetal compartments. In addition, the perfused cotyledon, the surrounding placental tissue as well as pre-perfusion placental tissue and umbilical cord plasma were also analysed. The PBDE analysis included Soxhlet extraction, clean-up by adsorption chromatography and GC-MS analysis.</p> <p>Results and Discussion</p> <p>Placental transfer of BDE-47 was faster and more extensive than for BDE-99. The fetal-maternal ratios (FM-ratio) after four hours of perfusion were 0.47 and 0.25 for BDE-47 and BDE-99, respectively, while the indicative permeability coefficient (IPC) measured after 60 minutes of perfusion was 0.26 h<sup>-1 </sup>and 0.10 h<sup>-1</sup>, respectively. The transport of BDE-209 seemed to be limited. These differences between the congeners may be related to the degree of bromination. Significant accumulation was observed for all congeners in the perfused cotyledon as well as in the surrounding placental tissue.</p> <p>Conclusion</p> <p>The transport of BDE-47 and BDE-99 indicates in utero exposure to these congeners. Although the transport of BDE-209 was limited, however, possible metabolic debromination may lead to products which are both more toxic and transportable. Our study demonstrates fetal exposure to PBDEs, which should be included in risk assessment of PBDE exposure of women of child-bearing age.</p

    Kidney/Bone Marrow Transplantation.

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    Within the past few years, a new conceptual view of transplantation has emerged, based on the observation that renal transplant recipients with extremely long (27-29 years) graft survival all have had evidence of donor cells in their peripheral blood, skin, and lymph nodes. They were thus chimeric. This led to the theory that chimerism is necessary for successful long-term engraftment. It also led to the next logical step of attempting to augment chimerism by transplanting donor bone marrow at the time of organ transplantation. Early reports of combined organ/bone marrow transplantation have suggested that it is safe and is associated with reasonable outcomes. In this paper, we discuss the outcome in the first 30 patients undergoing combined kidney/bone marrow transplantation

    Critical care service delivery across healthcare systems in low-income and low-middle-income countries: protocol for a systematic review

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    Introduction- Critical care in low-income and low-middle income countries (LLMICs) is an underdeveloped component of the healthcare system. Given the increasing growth in demand for critical care services in LLMICs, understanding the current capacity to provide critical care is imperative to inform policy on service expansion. Thus, our aim is to describe the provision of critical care in LLMICs with respect to patients, providers, location of care and services and interventions delivered. Methods and analysis- We will search PubMed/MEDLINE, Web of Science and EMBASE for full-text original research articles available in English describing critical care services that specify the location of service delivery and describe patients and interventions. We will restrict our review to populations from LLMICs (using 2016 World Bank classifications) and published from 1 January 2008 to 1 January 2020. Two-reviewer agreement will be required for both title/abstract and full text review stages, and rate of agreement will be calculated for each stage. We will extract data regarding the location of critical care service delivery, the training of the healthcare professionals providing services, and the illnesses treated according to classification by the WHO Universal Health Coverage Compendium. Ethics and dissemination- Reviewed and exempted by the Stanford University Office for Human Subjects Research and IRB on 20 May 2020. The results of this review will be disseminated through scholarly publication and presentation at regional and international conferences. This review is designed to inform broader WHO, International Federation for Emergency Medicine and partner efforts to strengthen critical care globally

    On the operator equation {AXBXD=EAXB-XD=E}

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