Lineage-specific differentiation of osteogenic progenitors from pluripotent stem cells reveals the FGF1-RUNX2 association in neural crest-derived osteoprogenitors.

Human pluripotent stem cells (hPSCs) can provide a platform to model bone organogenesis and disease. To reflect the developmental process of the human skeleton, hPSC differentiation methods should include osteogenic progenitors (OPs) arising from three distinct embryonic lineages: the paraxial mesoderm, lateral plate mesoderm, and neural crest. Although OP differentiation protocols have been developed, the lineage from which they are derived, as well as characterization of their genetic and molecular differences, has not been well reported. Therefore, to generate lineage-specific OPs from human embryonic stem cells and human induced pluripotent stem cells, we employed stepwise differentiation of paraxial mesoderm-like cells, lateral plate mesoderm-like cells, and neural crest-like cells toward their respective OP subpopulation. Successful differentiation, confirmed through gene expression and in vivo assays, permitted the identification of transcriptomic signatures of all three cell populations. We also report, for the first time, high FGF1 levels in neural crest-derived OPs-a notable finding given the critical role of fibroblast growth factors (FGFs) in osteogenesis and mineral homeostasis. Our results indicate that FGF1 influences RUNX2 levels, with concomitant changes in ERK1/2 signaling. Overall, our study further validates hPSCs' power to model bone development and disease and reveals new, potentially important pathways influencing these processes.

Atrial flutter with multilevel atrioventricular block and cyclical occurrence of varying QRS morphologies.

An electrocardiogram showing atrial flutter in which varying ratios of AV conduction and the cyclical recurrence of varying QRS morphologies are observed is presented.

Nurturing environmental champions: exploring the influence of environmental-specific servant leadership on environmental performance in the hospitality industry.

This study investigates the impact of environmental-specific servant leadership (ESSL) on environmental performance (EP) in the context of the hospitality industry. It further examines the mediating roles of environmental concern (EC) and employees' pro-social attitude (EPSA) in this relationship. Drawing on a sample of hospitality organizations, data was collected using self-report questionnaires from employees. Structural equation modeling (SEM) was employed to analyze the data and test the proposed model. The results demonstrate a positive and significant relationship between ESSL and EP in the hospitality industry. Furthermore, the study reveals that EC and EPSA play a mediating role in the relationship between ESSL and EP. The findings highlight the importance of ESSL in driving environmental performance and underscore the significance of fostering EC and EPSA among employees. Organizations can benefit from developing and nurturing ESSL leaders who inspire and motivate employees to embrace sustainability practices and contribute to a more environmentally responsible and sustainable industry.

The differential diagnosis of trunk and extremity dermal and sub-dermal lesions referred to a musculoskeletal oncology service.

OBJECTIVES: To determine the differential diagnosis of dermal and sub-dermal soft tissue masses which do not extend to the deep fascia that are referred to a specialist musculoskeletal oncology service. MATERIALS AND METHODS: Review of all patients referred to a specialist musculoskeletal oncology service over a 13-month period with a dermal or sub-dermal soft tissue mass which did not extend to the deep fascia based on MRI appearances. Data collected included age, gender, site and maximal lesion size, and final histological diagnosis for biopsied and/or excised lesions. RESULTS: 56 patients were included, 21 (37.5%) males and 35 (62.5%) females with mean age 49.75 years (range 5-86 years). 3 patients had 2 lesions making a total of 59 lesions, 11 (18.6%) dermal and 48 (81.4%) sub-dermal. Histological diagnosis was available in 44 (74.6%) cases, of which 11 (25%) were non-neoplastic, 23 (52.3%) were benign neoplasms, and 10 (22.7%) were malignant neoplasms. Although older age at presentation and greater mean maximal tumour dimension were seen with malignant lesions, these did not reach statistical significance (p = 0.154 and 0.102 respectively). There was also no relationship between skin involvement from sub-dermal lesions and malignancy, but 5 of 6 dermal lesions which showed an exophytic growth pattern were malignant. CONCLUSIONS: The differential diagnosis of dermal and sub-dermal lesions which do not reach the deep fascia is wide with a malignant lesion being the cause in almost one-quarter of cases.