Detecting metabolic differences in fetal and adult sheep adipose and skeletal muscle tissues

The primary metabolic pathway required to produce ATP differs as a result of tissue type, developmental stage and substrate availability. We utilized molecular and histological techniques to define the metabolic status in foetal and adult, adipose and skeletal muscle tissues. Redox ratios of these tissues were also determined optically by two‐photon microscopy. Adult perirenal adipose tissue had a higher optical redox ratio than fetal perirenal adipose tissue, which aligned with glycolysis being used for ATP production; whereas adult skeletal muscle had a lower optical redox ratio than fetal skeletal muscle, which aligned with oxygen demanding oxidative phosphorylation activity being utilized for ATP production. We have compared traditional molecular and microscopy techniques of metabolic tissue characterization with optical redox ratios to provide a more comprehensive report on the dynamics of tissue metabolism.     

Behavioral and mammary responses of adult female rhesus to strange infants

Approximately 90% of gonadally intact, ovariectomized, or postmenopausal feral-born multiparous rhesus macaques immediately behaved maternally and displayed strong attachment to unfamiliar neonatal rhesus infants offered to them, even though the females had not lived with infants for at least 12 months. Females showing such behavior and attachment also showed fluid secretion from their nipples even, in some cases, without oral stimulation of the nipples by the infant. Adult laboratory-reared nulliparous females did not adopt infants, although identically reared primiparous females adequately cared for their own first infants.     

Sugar transport asymmetry in human erythrocytes--the effect of bulk haemoglobin removal and the addition of methylxanthines

1. The glucose transport asymmetry of intact human red cells has been shown to be retained in pink erythrocyte ghosts (a preparation of membranes in which 95% of the red cell haemoglobin has been removed). 2. 3-Isobutyl-1-methylxanthine inhibits net glucose efflux in intact cells and ghosts and also net influx in cells. 5mM theophylline inhibits net efflux in ghosts. The inhibition type is mixed. The major effect is a decrease in the V value for net flux but a small increase in Km also occurs. 3-Isobutyl-1-methylxanthine binds the transport system from the external solution only. 3. Exchange flux of glucose shows virtually no inhibition by 3-isobutyl-1-methylxanthine. 4. The results are discussed in terms of models for sugar transport. A model consistent with the observed pattern of inhibition would be one in which transport is rate-limited by the membrane and in which net and exchange flux occur via separate transport cycles.     

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.     

In utero substrate restriction by placental insufficiency or maternal undernutrition decreases optical redox ratio in foetal perirenal fat

Intrauterine growth restriction (IUGR) can result from reduced delivery of substrates, including oxygen and glucose, during pregnancy and may be caused by either placental insufficiency or maternal undernutrition. As a consequence of IUGR, there is altered programming of adipose tissue and this can be associated with metabolic diseases later in life. We have utilised two sheep models of IUGR, placental restriction and late gestation undernutrition, to determine the metabolic effects of growth restriction on foetal perirenal adipose tissue (PAT). Two-photon microscopy was employed to obtain an optical redox ratio, which gives an indication of cell metabolism. PAT of IUGR foetuses exhibited higher metabolic activity, altered lipid droplet morphology, upregulation of cytochrome c oxidase subunit genes and decreased expression of genes involved in growth and differentiation. Our results indicate that there are adaptations in PAT of IUGR foetuses that might be protective and ensure survival in response to an IUGR insult.