Induction of primitive streak and mesendoderm formation in monolayer hESC culture by activation of TGF-β signaling pathway by Activin B

AbstractHuman embryonic stem cells (hESCs) have the ability to differentiate into all human cells, however controlling the differentiation has always been a challenge. In the present study we have investigated the direct differentiation of hESCs on MEFs by using TGF-β signaling pathway activators Activin A and Activin B. Activation of the TGF-β pathway with Activin B in low serum highly induced primitive streak and mesendoderm formation after 24h, which included up-regulation of SOX 17 and BRACHYURY protein and gene expression. Continuous stimulation with Activin B in 2% serum further induced mesendoderm formation by increased gene expression of Brachyury, SOX17, MEOX and FOX at the same time we found down-regulation of neuroectodermal marker genes. Further, by stimulating the mesodermal cells by BMP-2 we succeeded to induce mesenchymal like cells with high expression of mesenchymal markers including; MEOX, FOX, RUNX2, COL1 and OSTEOPONTIN. In conclusion we have directed the differentiation of hESCs as monolayer to primitive streak like cells with Activin B and further into pure mesoderm and mesenchymal like cells by BMP-2

Aging of marrow stromal (skeletal) stem cells and their contribution to age-related bone loss

AbstractMarrow stromal cells (MSC) are thought to be stem cells with osteogenic potential and therefore responsible for the repair and maintenance of the skeleton. Age related bone loss is one of the most prevalent diseases in the elder population. It is controversial whether MSC undergo a process of aging in vivo, leading to decreased ability to form and maintain bone homeostasis with age. In this review we summarize evidence of MSC involvement in age related bone loss and suggest new emerging targets for intervention

Powers, duties and liabilities of company directors:A comparative study of the law and practice in the UK and Saudi Arabia

Due to the globalisation of business and the concept of borderless business activities, these new phenomena need business management to be open and adopt and practice management’ skills with the international in mind, and give good consideration to the circumstances of the internationalisation of the business through directors having powers as provided under contract and law. The financial crises in previous years have demonstrated the importance of directors’ duties to manage the company's affairs properly; these crises were a result of many cases of fraud and mismanagement. The directors’ duties in the UK and the KSA have been codified to enhance the clarity of the law and make it easier for the responsibilities of directors towards the company and others to be understood. It also aims to prevent fraud and mismanagement that causes corporate collapse. This study investigates and analyses the powers, duties and liabilities of the directors in Saudi Arabia and the UK in order to demonstrate the extent to which these regulation work effectively. This is by a critical evaluation of relevant legislation and case law on the subject matter of the study and demonstrating practical problems, which may result from some legislation. By doing this, the study provides an accurate picture of the directors' powers, duties and liabilities, and provides solutions to practical problems of legislation in the same context

Saudi Arabia Science Teachers' Trends in Science Teaching Practices of Teaching Related Scientific Activities According to their Supervisors' Prospective and the Supervisors Estimates of The Importance of Such Practices

This paper investigated the Trends in Science Teaching Practices in-classroom science related activities among general education science teachers in Saudi Arabia from their supervisors’ perspectives. In addition, the supervisor's point of view about the importance of scientific related instructional activities was assessed. The data were collected through a validated questionnaire (19 items), which was administered to a random sample of 60 science supervisors (32 males, 28 females) from various parts of the Kingdome of Saudi Arabia. The results revealed that supervisors judged classroom activities of science teachers as teacher-centered rather than student-centered. As for supervisors’ estimates of the importance of teaching activities, the results indicated that they believed that the most important teaching activities were: developing the skills of science processes, and "impementing experiments to verify the information, and providing students with correct scientific ideas. The results showed that the least important activities were those that made the students active participants in the learning process. It was concluded that science supervisors were inclined to traditional activities that made the teacher and not the student the central core for the learning process

History and Genetics of Retinoblastoma

The history of retinoblastoma (RB) goes back to 1597 when Pieter Pawius of Amsterdam described a tumor that resembled retinoblastoma. “Fungus haematodes” was the first term used to describe retinoblastoma. Later, the American Ophthalmological Society approved the term retinoblastoma in 1926. The retinoblastoma protein is encoded by the RB1 gene located at 13q14. The functioning model of the tumor suppressor genes was first proposed by Alfred Knudson in the 1970s who precisely explained the hereditary mechanism of retinoblastoma. If both alleles of this gene are mutated, the protein is inactivated and this results in the development of retinoblastoma. One mutation can be either germline or somatic and the second one is always somatic. Differentiation between sporadic and germline retinoblastoma variants requires the identification of the RB1 germline status of the patient. This identification is important for assessing the risk of additional tumors in the same eye, the other eye, and the risk of secondary tumors. Thus, genetic testing is an important component of the management of all children diagnosed with retinoblastoma. In this chapter, we will go over the history, genetics, and counseling for patients with retinoblastoma

CDH1 and IL1-beta expression dictates FAK and MAPKK-dependent cross-talk between cancer cells and human mesenchymal stem cells

Is Figure S1 showing transfer of cellular components between hMSCs and cancer cells. (DOCX 214 kb

Bone morphogenetic protein 2 (BMP2) induces growth suppression and enhances chemosensitivity of human colon cancer cells

Additional file 5: Figure S4. BMP2 expression in CRC cell lines from the Cancer Cell Line Encyclopedia. Data are presented as mRNA expression (Log2)

In vitro differentiation of human skin-derived multipotent stromal cells into putative endothelial-like cells

<p>Abstract</p> <p>Background</p> <p>Multipotent stem cells have been successfully isolated from various tissues and are currently utilized for tissue-engineering and cell-based therapies. Among the many sources, skin has recently emerged as an attractive source for multipotent cells because of its abundance. Recent literature showed that skin stromal cells (SSCs) possess mesoderm lineage differentiation potential; however, the endothelial differentiation and angiogenic potential of SSC remains elusive. In our study, SSCs were isolated from human neonatal foreskin (hNFSSCs) and adult dermal skin (hADSSCs) using explants cultures and were compared with bone marrow (hMSC-TERT) and adipose tissue-derived mesenchymal stem cells (hADMSCs) for their potential differentiation into osteoblasts, adipocytes, and endothelial cells.</p> <p>Results</p> <p>Concordant with previous studies, both MSCs and SSCs showed similar morphology, surface protein expression, and were able to differentiate into osteoblasts and adipocytes. Using an endothelial induction culture system combined with an in vitro matrigel angiogenesis assay, hNFSSCs and hADSSCs exhibited the highest tube-forming capability, which was similar to those formed by human umbilical vein endothelial cells (HUVEC), with hNFSSCs forming the most tightly packed, longest, and largest diameter tubules among the three cell types. CD146 was highly expressed on hNFSSCs and HUVEC followed by hADSSCs, and hMSC-TERT, while its expression was almost absent on hADMSCs. Similarly, higher vascular density (based on the expression of CD31, CD34, vWF, CD146 and SMA) was observed in neonatal skin, followed by adult dermal skin and adipose tissue. Thus, our preliminary data indicated a plausible relationship between vascular densities, and the expression of CD146 on multipotent cells derived from those tissues.</p> <p>Conclusions</p> <p>Our data is the first to demonstrate that human dermal skin stromal cells can be differentiated into endothelial lineage. Hence, SSCs represents a novel source of stem/stromal cells for tissue regeneration and the vascularization of engineered tissues. Moreover, the CD146 investigations suggested that the microenvironmental niche might contribute to direct stromal cells multipotency toward certain lineages, which warrants further investigation.</p