Teaching Entrepreneurship And Micro-Entrepreneurship: An International Perspective

Entrepreneurship is an integral part of business education.  However, the concept is often confused or used synonymously with capitalism, perhaps because entrepreneurship is one of the four factors of production and profit maximization is considered as the single most important topic in teaching theory of the firm.  Using risk as the key variable in separating the domains of a capitalist and an entrepreneur, Schumpeter used innovation as the main function of an entrepreneur.  The popularity of micro-credit in the 1980s extended Schumpeter’s work to micro-entrepreneurship, popularly dubbed as “entrepreneurship with less”.  This paper traces the origin of the concept of entrepreneurship knowledge and extends it to micro-entrepreneurship with a goal of enhancing an understanding of the concept in the sphere of international business education

Tarjetas de crédito y su relación con las consultas a las centrales de riesgo en instituciones financieras, Marcona - 2021

El presente trabajo de investigación titulado: “Tarjetas de crédito y su relación con las Consultas a las Centrales de Riesgo en Instituciones Financieras, Marcona – 2021”, tuvo como objetivo analizar la relación de las tarjetas de crédito con las consultas a las centrales de riesgo en instituciones financieras, Marcona – 2021. El estudio tuvo un enfoque cuantitativo, de tipo aplicado, diseño no experimental, transversal, correlacional; tuvo como población a 22 personas, funcionarios de entidades financieras, la técnica empleada fue la encuesta con el instrumento cuestionario. Para la obtención de resultados se realizó un análisis descriptivo mediante el software SPSS V.25, que permitió determinar el Rho de Spearman de 0,795 y una significancia de 0,000 entre las variables Tarjetas de crédito y Centrales de riesgo. Se concluyó que las Tarjetas de crédito y las Centrales de riesgo tienen una relación positiva alta y estadísticamente significativa, esto debido a que los funcionarios realizan las consultas a las centrales de riesgo, al momento de colocar a los usuarios, las Tarjetas de crédito clásica, oro y platino y revolving, ya que estos productos se les asigna una línea de crédito según la calificación del cliente en las Centrales de riesgo

Evidence of meaningful levels of Trypanosoma cruzi in platelet concentrates from seropositive blood.

BACKGROUND: According to the reported cases of transfusion-acquired Trypanosoma cruzi infection, the risk of T. cruzi transfusion transmission appears to be higher with platelet (PLT) products than with other blood components. The aim of this study was to investigate by quantitative real-time polymerase chain reaction (qPCR) the parasitic load detected in leukoreduced plasma and PLT concentrates collected by apheresis from seropositive T. cruzi blood donors and compare them with peripheral whole blood (WB). STUDY DESIGN AND METHODS: During 2011 to 2013, a prospective study was carried out in a group of blood donors originating from Chagas-endemic areas but who are now living on the island of Majorca, Spain. Leukoreduced plasma and PLT concentrates were collected by apheresis from seropositive blood donors with detectable parasitemias in peripheral WB. RESULTS: Seropositivity was found in 23 of 1201 donors studied (1.9%), and T. cruzi DNA with less than 1 parasite equivalent/mL was detected in peripheral WB in 60.86% (14 of 23) of these. The study in blood components obtained by apheresis from these donors showed that T. cruzi DNA with a mean ± SD parasitic load of 5.33 ± 6.12 parasite equivalents/mL was detected in 100% of the PLT concentrate samples. Parasite DNA was undetectable in the extract taken from plasma collected from donors with a positive qPCR in peripheral WB. CONCLUSION: The higher parasitic load found in PLT concentrates compared to plasma and peripheral WB would explain the higher transfusion transmission risk of Chagas disease associated with PLT transfusions described in the reported cases of transfusion-acquired T. cruzi infection

Extracellular vesicles-mediated intercellular communication: roles in the tumor microenvironment and anti-cancer drug resistance.

The tumor microenvironment represents a complex network, in which tumor cells not only communicate with each other but also with stromal and immune cells. Current research has demonstrated the vital role of the tumor microenvironment in supporting tumor phenotype via a sophisticated system of intercellular communication through direct cell-to-cell contact or by classical paracrine signaling loops of cytokines or growth factors. Recently, extracellular vesicles have emerged as an important mechanism of cellular interchange of bioactive molecules. Extracellular vesicles isolated from tumor and stromal cells have been implicated in various steps of tumor progression, such as proliferation, angiogenesis, metastasis, and drug resistance. Inhibition of extracellular vesicles secretion, and thus of the transfer of oncogenic molecules, holds promise for preventing tumor growth and drug resistance. This review focuses on the role of extracellular vesicles in modulating the tumor microenvironment by addressing different aspects of the bidirectional interactions among tumor and tumor-associated cells. The contribution of extracellular vesicles to drug resistance will also be discussed as well as therapeutic strategies targeting extracellular vesicles production for the treatment of cancer

Detection and Quantification of Viable and Nonviable Trypanosoma cruzi Parasites by a Propidium Monoazide Real-Time Polymerase Chain Reaction Assay.

Molecular techniques based on real-time polymerase chain reaction (qPCR) allow the detection and quantification of DNA but are unable to distinguish between signals from dead or live cells. Because of the lack of simple techniques to differentiate between viable and nonviable cells, the aim of this study was to optimize and evaluate a straightforward test based on propidium monoazide (PMA) dye action combined with a qPCR assay (PMA-qPCR) for the selective quantification of viable/nonviable epimastigotes of Trypanosoma cruzi PMA has the ability to penetrate the plasma membrane of dead cells and covalently cross-link to the DNA during exposure to bright visible light, thereby inhibiting PCR amplification. Different concentrations of PMA (50-200 μM) and epimastigotes of the Maracay strain of T. cruzi (1 × 105-10 parasites/mL) were assayed; viable and nonviable parasites were tested and quantified by qPCR with a TaqMan probe specific for T. cruzi In the PMA-qPCR assay optimized at 100 μM PMA, a significant qPCR signal reduction was observed in the nonviable versus viable epimastigotes treated with PMA, with a mean signal reduction of 2.5 logarithm units and a percentage of signal reduction > 98%, in all concentrations of parasites assayed. This signal reduction was also observed when PMA-qPCR was applied to a mixture of live/dead parasites, which allowed the detection of live cells, except when the concentration of live parasites was low (10 parasites/mL). The PMA-qPCR developed allows differentiation between viable and nonviable epimastigotes of T. cruzi and could thus be a potential method of parasite viability assessment and quantification

Strategies for reducing the risk of transfusion-transmitted leishmaniasis in an area endemic for Leishmania infantum: a patient- and donor-targeted approach

Background. In the Balearic Islands, as in other areas of the Mediterranean basin, there is a significant proportion of asymptomatic Leishmania (L.) infantum-infected blood donors, who may represent an important threat to transfusion safety. The Balearic Islands blood bank, located in an area endemic for L. infantum, carried out a study of donors and patients to investigate the impact of this infectious disease on blood safety in the region. Materials and methods. Twenty asymptomatic Leishmania-infected blood donors were followed-up between 2008 and 2011 to investigate the evolution of Leishmania infection in asymptomatic carriers. Their blood was periodically tested for anti-Leishmania antibodies by western blot and for Leishmania DNA by quantitative polymerase chain reaction (qPCR). Additionally, the prevalence of L. infantum infection was investigated in a group of 68 multiply transfused patients to ascertain the risk of transfusion-transmitted leishmaniasis (TTL) in the region, taking into account regular blood component production practices such as pre-storage leucodepletion and pathogen reduction technology. Results. All 20 donors remained asymptomatic over the study period (2008-2011). Most donors had repeatedly positive qPCR results, either persistently or intermittently, but showed no symptoms of Leishmaniasis. Levels of parasitaemia were remarkably low in asymptomatic donors, with values ≤1 parasite/mL. Despite multiple transfusions received over 15 years, no transfused patient studied was infected with L. infantum. Discussion. L. infantum-infected donors can remain asymptomatic for at least 3 years. In our region, no cases of TTL were detected, despite an active search in multiply transfused patients. This seems to be related to two independent variables: (i) a low concentration of the parasite in the peripheral blood of asymptomatic carriers and (ii) the application of methods with proven efficacy against TTL, such as leucodepletion and pathogen reduction technology

The Role Of MicroRNA-375 In Head And Neck Squamous Cell Carcinoma Invasion

Despite advances in treatment, the five-year survival rate for patients with head and neck squamous cell carcinoma (HNSCC) has shown little improvement in recent decades. MicroRNAs regulate multiple processes involved in carcinogenesis and cancer progression and have been identified as potential diagnostic and prognostic markers. We conducted microRNA expression profiling of HNSCC patient and paired normal samples to identify microRNAs with significantly altered expression. We identified miR375 as the most consistently downregulated miRNA in tumor samples. Patients in the lowest quartile of miR-375 tumor:normal (T:N) expression showed significantly decreased disease-specific survival, increased incidence of locoregional recurrence and distant metastasis. We evaluated possible mechanisms by which miR-375 expression would cause altered HNSCC invasion. Stable transductant cell lines with increased expression of miR-375 were generated from HNSCC cell lines utilizing lentiviral constructs expressing either the precursor form of miR-375 or an empty vector control. We observed that HNSCC cells with increased miR-375 expression exhibited significantly reduced cell invasion in vitro. We also observed that elevated miR-375 expression suppressed matrix degradation as well as the frequency of mature invadopodia. In addition, higher miR-375 expression led to significant reductions in the secreted levels and mRNA expression levels of specific proteases. We utilized a quantitative proteomic strategy, stable isotope labeling with amino acids in cell culture (SILAC) and reverse-phase liquid chromatography mass spectrometry (RPLC-MS) to compare differences in protein abundance between UMSCC1 expressing high or low levels of miR-375. The top candidates that emerged were L-plastin and vimentin. We identified runt-related transcription factor 1 (RUNX1) as a miR-375 target candidate that regulates vimentin and L-plastin expression. We also showed that knockdown of L-plastin and vimentin reduced cell invasion. In summary, we have identified miR-375 as potential prognostic marker of poor outcome and metastasis in HNSCC. We demonstrated that increased miR-375 expression levels in HNSCC cells suppressed cell invasion in part through reduced invadopodial function. These effects may occur through suppression of RUNX1, which can drive expression of vimentin and L-plastin

Detection and Quantification of Viable and Nonviable Trypanosoma cruzi Parasites by a Propidium Monoazide Real-Time Polymerase Chain Reaction Assay.

Molecular techniques based on real-time polymerase chain reaction (qPCR) allow the detection and quantification of DNA but are unable to distinguish between signals from dead or live cells. Because of the lack of simple techniques to differentiate between viable and nonviable cells, the aim of this study was to optimize and evaluate a straightforward test based on propidium monoazide (PMA) dye action combined with a qPCR assay (PMA-qPCR) for the selective quantification of viable/nonviable epimastigotes of Trypanosoma cruzi PMA has the ability to penetrate the plasma membrane of dead cells and covalently cross-link to the DNA during exposure to bright visible light, thereby inhibiting PCR amplification. Different concentrations of PMA (50-200 μM) and epimastigotes of the Maracay strain of T. cruzi (1 × 105-10 parasites/mL) were assayed; viable and nonviable parasites were tested and quantified by qPCR with a TaqMan probe specific for T. cruzi In the PMA-qPCR assay optimized at 100 μM PMA, a significant qPCR signal reduction was observed in the nonviable versus viable epimastigotes treated with PMA, with a mean signal reduction of 2.5 logarithm units and a percentage of signal reduction > 98%, in all concentrations of parasites assayed. This signal reduction was also observed when PMA-qPCR was applied to a mixture of live/dead parasites, which allowed the detection of live cells, except when the concentration of live parasites was low (10 parasites/mL). The PMA-qPCR developed allows differentiation between viable and nonviable epimastigotes of T. cruzi and could thus be a potential method of parasite viability assessment and quantification

The effectiveness of riboflavin and ultraviolet light pathogen reduction technology in eliminating Trypanosoma cruzi from leukoreduced whole blood

BACKGROUNDThe parasitic Chagas disease is caused by the protozoan Trypanosoma cruzi, which is mainly transmitted by insect vectors. Other infection routes, both in endemic and in nonendemic areas, include organ and marrow transplantation, congenital transmission, and blood transfusion. Asymptomatic chronic chagasic individuals may have a low and transient parasitemia in peripheral blood and, consequently, they can unknowingly transmit the disease via blood transfusion. Riboflavin and ultraviolet (UV) light pathogen reduction is a method to reduce pathogen transfusion transmission risk based on damage to the pathogen nucleic acids.STUDY DESIGN AND METHODSIn this study, we tested the effectiveness of this technology for the elimination of T. cruzi parasites in artificially contaminated whole blood units (WBUs) and thus for decreasing the risk of T. cruzi transfusion transmission. The contaminated WBUs were leukoreduced by filtration and treated with riboflavin and UV light. The level of pathogen reduction was quantified by a real-time polymerase chain reaction (qPCR) and a real-time reverse transcription-polymerase chain reaction (RT-qPCR) as a viability assay.RESULTSThe RNA (cDNA) quantification of the parasites showed a more than 99% reduction of viable T. cruzi parasites after leukoreduction and a complete reduction (100%) after the riboflavin and UV light treatment.CONCLUSIONRiboflavin and UV light treatment and leukoreduction used in conjunction appears to eliminate significant amounts of viable T. cruzi in whole blood. Both strategies could complement other blood bank measures already implemented to prevent the transmission of T. cruzi via blood transfusion

Evidence of meaningful levels of Trypanosoma cruzi in platelet concentrates from seropositive blood.

BACKGROUND: According to the reported cases of transfusion-acquired Trypanosoma cruzi infection, the risk of T. cruzi transfusion transmission appears to be higher with platelet (PLT) products than with other blood components. The aim of this study was to investigate by quantitative real-time polymerase chain reaction (qPCR) the parasitic load detected in leukoreduced plasma and PLT concentrates collected by apheresis from seropositive T. cruzi blood donors and compare them with peripheral whole blood (WB). STUDY DESIGN AND METHODS: During 2011 to 2013, a prospective study was carried out in a group of blood donors originating from Chagas-endemic areas but who are now living on the island of Majorca, Spain. Leukoreduced plasma and PLT concentrates were collected by apheresis from seropositive blood donors with detectable parasitemias in peripheral WB. RESULTS: Seropositivity was found in 23 of 1201 donors studied (1.9%), and T. cruzi DNA with less than 1 parasite equivalent/mL was detected in peripheral WB in 60.86% (14 of 23) of these. The study in blood components obtained by apheresis from these donors showed that T. cruzi DNA with a mean ± SD parasitic load of 5.33 ± 6.12 parasite equivalents/mL was detected in 100% of the PLT concentrate samples. Parasite DNA was undetectable in the extract taken from plasma collected from donors with a positive qPCR in peripheral WB. CONCLUSION: The higher parasitic load found in PLT concentrates compared to plasma and peripheral WB would explain the higher transfusion transmission risk of Chagas disease associated with PLT transfusions described in the reported cases of transfusion-acquired T. cruzi infection