Given an abstract, generate a keyword (a noun phrase) that best describes the focus or contribution of the paper. Such keywords can be directly from the given abstract or outside it.

[Q]: Abstract: The steady state levels of the prodynorphin-derived opioid peptides, dynorphin A, dynorphin B, and alpha-neo-endorphin, have been extensively studied in the magnocellular/posterior pituitary system of the rat. To determine whether the rat system serves as a general model for prodynorphin processing in the mammalian posterior pituitary, we examined the steady state levels of prodynorphin-derived opioid peptides in the posterior pituitary systems of representatives of three diverse orders of mammals: guinea pig (order Rodentia), pig (order Artiodactyla), and rhesus monkey (order Primates). In each species studied there was evidence for species-specific deviations from the rat model. The most pronounced differences were observed with respect to the conversion of dynorphin A-(1-17) to dynorphin A-(1-8). In rodents, rats, and guinea pigs, under steady state conditions, the molar ratios of these forms are approximately 1:2 and 2.5:1, respectively. However, in the pig and rhesus monkey, the molar ratios of these forms are 10:1 and 14:1, respectively. Thus, under steady state conditions, the conversion of dynorphin A-(1-17) to dynorphin A-(1-8) appears to be a minor event in porcine and rhesus monkey posterior pituitary. Species-specific variations were also observed with respect to the steady state levels of alpha-neo-endorphin and dynorphin B-(1-13). In addition, the results of these studies suggest that the conversion of prodynorphin-derived opioids to leu-enkephalin probably represents a minor event in the species studied.
[A]: Animal

[Q]: Abstract: The effects of dobutamine on hemodynamic and oxygen transport were evaluated in 43 studies on 34 critically ill general (noncardiac) surgical patients. Dobutamine, beginning at a low dose (2.5 micrograms/kg X min) significantly increased cardiac index (CI), oxygen delivery (DO2), and oxygen consumption (VO2), while decreasing mean arterial pressure, pulmonary artery and wedge pressures, and systemic and pulmonary vascular resistances; blood gases, pH, and pulmonary shunt were not significantly changed. These effects were seen in postoperative and septic patients, as well as in patients with normal, low, and high control CI. These responses were poor in terminally ill and hypovolemic patients; however, when the latter were given additional fluids, their responses were markedly improved. The hemodynamic effects of dobutamine are well known, but the DO2 and VO2 effects, which suggest improved tissue perfusion, have not been appreciated.
[A]: Adolescence

[Q]: Abstract: The extensive range of specificities of T-cell receptors is generated, as for immunoglobulins, by rearrangement of genetic information. Much valuable information about rearrangement processes has been inferred by comparing DNA from (monoclonal) lymphoid lines with germ-line DNA and, for B cells, from rearrangements in some Abelson murine leukaemia virus-transformed cell lines. However, because it is difficult to isolate and grow precursor populations, it has not proved possible to study rearrangements occurring in normal untransformed cells in vitro. Here we show that a single T-cell precursor colonizing an alymphoid thymus lobe in organ culture can generate multiple receptor beta-chain gene rearrangements. These observations provide unequivocal evidence for the intra-thymic diversification of the T-cell repertoire. They also offer the possibility of investigating rearrangement and its control in the clonal progeny of a single normal T-cell precursor without the perturbations involved in the use of viral transformation or the production of T-cell hybridomas.
[A]:
Animal