Encapsulation of Human Umbilical Cord Mesenchymal Stem Cells in LunaGel Photocrosslinkable Extracellular Matrix and Subcutaneous Transplantation in Mice.

Stem cells have significant potential in regenerative medicines. However, a major issue with implanting stem cells in the regeneration of new tissue is the methods to implant them and cell viability and functions before and after implantation. Here we developed a simple yet effective method that used photo-crosslinkable gelatin-based hydrogel (LunaGelTM) as a scaffold for the encapsulation, expansion, and eventually, transplantation of human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) into mice subcutaneously. We demonstrated the proliferation and maintenance of the original expression of mesenchymal stem cell markers as well as the ability to differentiate into mesoderm-derived cells. The hydrogel was highly stable with no signs of degradation after 20 days in PBS. The hUC-MSCs remained viable after transplantation into mice's subcutaneous pockets and migrated to integrate with the surrounding tissues. We showed a collagen-rich layer surrounding the transplanted cell-laden scaffold indicating the effects of growth factors secreted by the hUC-MSCs. A connective tissue layer was found between the implanted cell-laden scaffold and the collagen layer, and immunohistochemical staining results suggested that this tissue was derived from the MSCs which migrated from within the scaffold. The results, thus, also suggested a protective effect the scaffold has on the encapsulated cells from the antibodies and cytotoxic cells of the host immune system.

Stem cell sheet fabrication from human umbilical cord mesenchymal stem cell and Col-T scaffold.

Today, stem cell therapy has been shown to be a remarkable progress and an important application in the regeneration of defective tissues and organs. To deliver stem cells to the injured area, several methods have been proposed such as an intravenous infusion, direct damaged tissue injection, or stem cell sheet transplantation. In this study, we aimed to fabricate a stem cell sheet by culturing human umbilical cord mesenchymal stem cells (hUC-MSCs) on a Col-T scaffold to recover the structure and function of damaged tissues. The results showed that cells reach confluent on the scaffold surface 18 h after seeding. These stem cells were able to survive and proliferate on Col-T scaffold. The average tensile strength of the stem cell sheet was 2.65 MPa. The sheet reached the sterile standards when tested for total bacteria, Candida albicans, Pseudomonas aeruginosa, and Staphylococcus aureus according to Circular number 06/2011/TT-BYT of Vietnam Ministry of Health. In addition, the stem cell sheet was non-toxic when evaluated for exposure toxicity and fluid toxicity according to iSO-10993. Importantly, 5 days after culturing on the Col-T scaffold, the seeded hUC-MSCs were still possessed all properties of MSC such as spindle-shaped, adhesive, could differentiate into mesoderm-derived cells, showed to be CD90, CD105, CD73 positive and CD45, CD34, CD11b, CD19, HLA-DR negative. In summary, our study was successful in creating a stem cell sheet from hUC-MSCs and Col-T scaffold for subsequent in vivo transplantation in the future.

Attending Reviews of Residents Correlate with ABR Qualifying (Core) Examination Failure.

RATIONALE AND OBJECTIVES: Since the American Board of Radiology (ABR) instituted the new system of board certification, there has been much discussion as to the test's validity. We decided to evaluate if subjective evaluation of resident performance correlated with ABR Qualifying (Core) Examination performance at this single institution. MATERIALS AND METHODS: Data regarding resident evaluation scores by attending physicians and passage of board examinations was gathered regarding residents who had taken the ABR Qualifying (Core) Examination from 2013 through 2019 for a total of 42 residents, eight of whom failed the ABR Qualifying (Core) Examination on their first attempt. A univariate analysis comparing scores with resident passage or failure of the ABR Qualifying (Core) Examination on the first attempt and analyses correcting for class year only and class year and number of evaluations was performed. RESULTS: The non-weighted average evaluation score of years 1, 2, and 3 was 80.24% for those who failed the ABR Qualifying (Core) Examination and 83.71 % for those who passed. On univariate analysis along with analyses correcting for class year only and class year along with number of evaluations, there was a statistically significant correlation with decreased evaluation scores averaged over the three years of residency and failure of the ABR Qualifying (Core) Examination (p = 0.0102, p = 0.003, and p = 0.0043). The statistical significance held for the average numerical score in each individual year of training in all analyses except for year 1 of the univariate analysis (p = 0.1264). CONCLUSION: At the studied institution, there was a statistically significant correlation between lower subjective faculty evaluation scores and failure of the ABR Qualifying (Core) Examination.

Anti-Aging Effects of a Serum Based on Coconut Oil Combined with Deer Antler Stem Cell Extract on a Mouse Model of Skin Aging.

Anti-aging is one of the top goals in the field of health care and aesthetics. Anti-aging cosmetics derived from nature are oriented to long-term development, bringing safety to users and being environmentally friendly. The aim of this study was to develop an anti-aging cosmetic formulation process based on coconut oil in combination with deer antler stem cell extract. The results show that the presence of deer antler stem cell extract added to the foundation made the serum product highly stable and helped improve skin aging significantly after 2 weeks of use. The skin site where the serum product was applied showed a smooth and elastic skin surface, with very few fine lines and shallow wrinkles. Serum reduced the number of wrinkles (48.09% compared to commercial serum (ME) and 60.31% compared to positive control (PC)), reduced skin recovery time (39.31% compared to ME and 67.1% of PC) after two weeks of use. After 2 weeks of use, collagen density increased 10.18% compared to ME and 63.76% compared to control. Epidermal thickness increased by 106.1% compared to PC and 121.7% compared to ME.

Draft genome sequence data of Streptomyces sp. SS1-1, an endophytic strain showing cytotoxicity against the human lung cancer A549 cell line.

We report in this article the cytotoxicity of Streptomyces sp. SS1-1 against the human lung cancer A549 cell line, its draft genome sequence and a total of 20 predicted secondary metabolite biosynthetic gene clusters. Streptomyces sp. SS1-1 was an endophytic bacterial strain isolated from the plant Catharanthus roseus in Ho Chi Minh City, Vietnam. When cultured in the PY medium, this strain shows a cytotoxic effect on the A549 cell line. The draft genome of Streptomyces sp. SS1-1 has four contigs of total 7,815,656 bp and the GC content of this genome is 72.2%. AntiSMASH analysis reveals 20 putative biosynthetic gene clusters for the largest contig. The genome sequencing of Streptomyces sp. SS1-1 is essential for the molecular identification of gene cluster(s) responsible for secondary metabolite(s) with cytotoxic activity.

Predictors for Failing the American Board of Radiology Core Examination.

OBJECTIVE. Since the American Board of Radiology (ABR) instituted its new board certification pathway, our residency program has had more residents fail the core examination than was typical with the prior pathway. We performed a single-center retrospective study to evaluate predictors of ABR core examination failure. MATERIALS AND METHODS. Data regarding U.S. Medical Licensing Examination (USMLE) steps 1 and 2, ACR diagnostic radiology in-training examinations, the number of image interpretations, academic degree (doctor of medicine or doctor of osteopathy), status as an American or foreign medical graduate, and Alpha Omega Alpha national medical honor society status were gathered and evaluated through logistic regression and generalized additive logistic regression. Data were gathered for all residents who took the ABR core examination from 2013 to 2017. RESULTS. Six of 30 residents (20%) failed the ABR core examination on the first attempt. The ACR in-training examination scores for 1st- and 3rd-year residents were significantly related to ABR core examination failure (p = 0.027 and p = 0.035, respectively), with significant nonlinearity (p = 0.037 and p = 0.033, respectively). The suggested baseline percentile score was the 30th percentile for 1st-year residents and the 20th percentile for 3rd-year residents. USMLE step 1 and 2 scores were significantly related to ABR core examination failure (p = 0.041 and p = 0.043, respectively), without significant nonlinearity (p = 0.35 and p = 0.09, respectively). However, residents with scores of less than 220 on USMLE steps 1 and 2 seemed to be at risk. CONCLUSION. Low scores on USMLE steps 1 and 2 and 1st- and 3rd-year ACR in-training examinations were associated with ABR core examination failure. If validated more broadly, these cutoffs may serve as predictors of ABR core examination failure and may facilitate identification and remediation of at-risk residents.