Carbon dioxide tolerance studies

Human tolerance to exposure of carbon dioxide environmen

Increased adrenal secretion of norepinephrine and epinephrine after endotoxin and its reversal with corticosteroids

Two groups of dogs were subjected to an LD60 of E. coli endotoxin. Group II animals were pretreated with 30 mg/kg of methyl prednisolone sodium succinate before the intravenous endotoxin. All animals had hypotension and diminished cardiac index after endotoxin administration.The nonsteroid dogs, Group I, demonstrated increased adrenal secretion of norepinephrine and epinephrine. Arterial plasma catecholamines were comparable. Group II steroid-treated animals demonstrated lower adrenal secretion of norepinephrine and epinephrine when compared to Group I, nonsteroid animals. These results demonstrate that pretreatment with pharmacologic doses of synthetic corticosteroids exerts a specific effect on the adrenal medulla in endotoxin shock that profoundly limits adrenal catecholamine release.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22090/1/0000514.pd

Finite size effects near the onset of the oscillatory instability

A system of two complex Ginzburg - Landau equations is considered that applies at the onset of the oscillatory instability in spatial domains whose size is large (but finite) in one direction; the dependent variables are the slowly modulated complex amplitudes of two counterpropagating wavetrains. In order to obtain a well posed problem, four boundary conditions must be imposed at the boundaries. Two of them were already known, and the other two are first derived in this paper. In the generic case when the group velocity is of order unity, the resulting problem has terms that are not of the same order of magnitude. This fact allows us to consider two distinguished limits and to derive two associated (simpler) sub-models, that are briefly discussed. Our results predict quite a rich variety of complex dynamics that is due to both the modulational instability and finite size effects

Global stability properties of a hyperbolic system arising in pattern formation

Global stability properties of a hyperbolic system arising in pattern formatio