Teratogenic effects of excess glucose on head-fold rat embryos in culture.

Rat embryos explanted at nine and one-half days of gestation (early head-fold stages) were cultured for 48 hours in rotating bottles containing rat serum and a gas phase. Addition of 12-15 mg/ml of D-glucose to the culture medium resulted in severe abnormalities and retarded development in a high proportion of embryos, whether or not the osmolarity increase brought about by the addition of glucose was corrected. The raised osmolarity, however, increased the frequency and severity of malformations observed. L-glucose produced no abnormalities, though embryonic development was retarded.     

Nutrient requirements of rat embryos undergoing organogenesis in vitro

Rat embryos at the head-fold stage were cultured in rotating bottles for 2 days in rat serum extensively dialysed against glucose-free BSS, and to which various energy sources and nutrients were added. Optimum growth and differentiation, virtually indentical with that obtained in while serum and to that seen during the corresponding period in vivo, were obtained with the addition of glucose and certain vitamins: pantothenic acid and riboflavin had a general beneficial effect on development, i-inositol suppressed neural tube defects, and folic acid significantly improved growth of the embryos.     

Rheological properties of cross-linked hyaluronan-gelatin hydrogels for tissue engineering

Hydrogels that mimic the natural extracellular matrix (ECM) are used in three-dimensional cell culture, cell therapy, and tissue engineering. A semi-synthetic ECM based on cross-linked hyaluronana offers experimental control of both composition and gel stiffness. The mechanical properties of the ECM in part determine the ultimate cell phenotype. We now describe a rheological study of synthetic ECM hydrogels with storage shear moduli that span three orders of magnitude, from 11 to 3 500 Pa, a range important for engineering of soft tissues. The concentration of the chemically modified HA and the cross-linking density were the main determinants of gel stiffness. Increase in the ratio of thiol-modified gelatin reduced gel stiffness by diluting the effective concentration of the HA component.