Tissue engineering can be used to restore, maintain, or enhance tissues and organs. The potential impact of this field, however, is far broader-in the future, engineered tissues could reduce the need for organ replacement, and could greatly accelerate the development of new drugs that may cure patients, eliminating the need for organ transplants altogether.

Injury to articular cartilage predisposes that joint to further degeneration and eventually osteoarthritis. Recent studies have demonstrated the feasibility of using chondrocytes together with different biomaterial carriers as grafts for the repair of cartilage defects. The following study was undertaken to determine the effect of a variety of these materials on chondrocyte growth and extracellular matrix synthesis. We cultured chondrocytes on several commonly used materials and compared their rates of synthesis of proteoglycan and collagen. Additionally, we evaluated them in a closed culture recirculating system on these materials and compared them with standard culture techniques. This was done to see whether such a bioreactor-type system can be used to enhance the quality of in vitro reconstructed tissues. Our results demonstrated marked variability with respect to how chondrocytes responded to culture on the various materials. Bioabsorbable polymers such as polyglycolic acid (PGA)--enhanced proteoglycan synthesis, whereas collagen matrices stimulated synthesis of collagen. The use of the closed culture system, in general, improved the rates of synthesis of collagen and proteoglycan on the different material scaffolds. Exceptions were collagen synthesis on collagen matrices: use of the closed culture system did not enhance the rate of synthesis. Rates of proteoglycan synthesis on PGA scaffold initially was higher in the closed culture system but did not sustain a difference over the entire course of the 3-week culture period. This study demonstrates the importance of carrier material for the purpose of cartilage tissue reconstruction in vitro.

Most patients with active vitiligo (82% of 61) have antibodies to antigens of normal human melanocytes that can be detected by specific immunoprecipitation of radioiodinated, detergent-soluble, melanocyte macromolecules. Such antibodies were present in only 12% of patients with melanoma and in none of 35 patients with nonpigmentary skin diseases. The antibodies were directed to a common antigen(s) on melanocytes that was not present on normal fibroblasts or keratinocytes. These observations suggest that vitiligo is an autoimmune disease mediated by antibodies to melanocyte-associated antigen(s).

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The International Society for Stem Cell Research has updated its Guidelines for Stem Cell Research and Clinical Translation in order to address advances in stem cell science and other relevant fields, together with the associated ethical, social, and policy issues that have arisen since the last update in 2016. While growing to encompass the evolving science, clinical applications of stem cells, and the increasingly complex implications of stem cell research for society, the basic principles underlying the Guidelines remain unchanged, and they will continue to serve as the standard for the field and as a resource for scientists, regulators, funders, physicians,