Incubation

About: Incubation is a research topic. Over the lifetime, 5748 publications have been published within this topic receiving 126541 citations.

Maturation of cardiovascular control mechanisms in the embryonic emu (Dromiceius novaehollandiae).

Abstract: Our understanding of avian embryonic cardiovascular regulation has been based on studies in chickens. The present study was undertaken to determine if the patterns established in chickens are generally applicable to the emu, a ratite bird species. We studied cardiovascular physiology over the interval from 60% to 90% of the emu’s 50-day incubation period. During this period, embryonic emus exhibit a slight fall in resting heart rate (from 171·beats·min ‐1 to 154·beats·min ‐1 ) and a doubling of mean arterial pressure (from 1.2·kPa to 2.6·kPa). Exposures to 15% or 10% O2 initially decreased heart rate during the first period of emu incubation studied [60% of incubation (60%I)] but increased heart rate in the 90%I group. Arterial pressure responded to hypoxia with an initial depression (‐1.6·kPa) at 60%I and 70%I but showed no response during the later periods of incubation (80%I and 90%I). In addition, tonic stimulation of both cholinergic and adrenergic (α and β) receptors was present on heart rate at 70%I, with the cholinergic and βadrenergic tone increasing in strength by 90%I. Arterial pressure was dependent on a constant β-adrenergic and constant α-adrenergic tone from 60%I to 90%I. A comparison with embryonic white leghorn chickens over a similar window of incubation revealed that emus and white leghorn chickens both possess an adrenergic tone on heart rate and pressure but that only emus possess a cholinergic tone on heart rate. Collectively, these data indicate that the maturation of cardiovascular control systems differs between white leghorn chickens and emus, inviting investigation of additional avian species to determine other patterns.

Size, Growth, and Survival Are Reduced at Cool Incubation Temperatures in the Temperate Lizard Oligosoma suteri (Lacertilia: Scincidae)

Abstract: Reptile eggs from cool temperate environments often experience cool incubation conditions, which may have long-term consequences for individual fitness. We studied the effects of artificial incubation regimes on size, growth, and survival of New Zealand's only endemic oviparous lizard, Oligosoma suteri. Eggs were randomly distributed among three incubation temperatures (18, 22, 26 C) and two water potentials (−120 and −270 kPa). Hatchlings incubated at 22 C and −120 kPa were significantly larger for most measurements than hatchlings from other incubation treatments. Juveniles from the two higher incubation temperatures had more rapid growth and ultimately greater size by 12 months, as well as significantly higher survival to 18 months, than did 18 C incubated individuals. Hatchling size did not influence survival. Our data suggest that the restricted northern distribution of O. suteri results from ecological constraints caused by the negative effects of cool incubation temperatures on embryos and...

Evidence for Intracellular Aggregation of Hypericin and the Impact on its Photocytotoxicity in PAM 212 Murine Keratinocytes

Abstract: We have assessed photoinduced toxicity of hypericin in PAM 212 murine keratinocytes and the relationship between concentration, incubation time and light fluence to evaluate the effect of intracellular aggregation at high concentrations Confocal microscopy was used to establish the subcellular localization of hypericin at 5 and 50 μM and incubation times of 1 and 3 h From fluorescence uptake time course studies, intracellular hypericin was demonstrated to exist predominantly in the monomeric form for up to 26 h incubation at 5 μM However, there was a pronounced aggregation effect at 50 μM, with intracellular hypericin fluorescence levels initially showing an increase followed by a decrease with incubation time This effect was subsequently shown to exert an effect on the phototoxicity of hypericin On irradiation, the photocytotoxicity for 1 and 7 h incubation with 50 μM hypericin was comparable, whereas using 5 μM the photocytotoxicity showed good correlation with the intracellular fluorescence measurements at 1 and 7 h incubation

Modeling the Incubation Period of Inhalational Anthrax

Abstract: Ever since the pioneering work of Philip Sartwell, the incubation period distribution for infectious diseases is most often modeled using a lognormal distribution. Theoretical models based on underlying disease mechanisms in the host are less well developed. This article modifies a theoretical model originally developed by Brookmeyer and others for the inhalational anthrax incubation period distribution in humans by using a more accurate distribution to represent the in vivo bacterial growth phase and by extending the model to represent the time from exposure to death, thereby allowing the model to be fit to nonhuman primate time-to-death data. The resulting incubation period distribution and the dose dependence of the median incubation period are in good agreement with human data from the 1979 accidental atmospheric anthrax release in Sverdlovsk, Russia, and limited nonhuman primate data. The median incubation period for the Sverdlovsk victims is 9.05 (95% confidence interval = 8.0-10.3) days, shorter than previous estimates, and it is predicted to drop to less than 2.5 days at doses above 10(6) spores. The incubation period distribution is important because the left tail determines the time at which clinical diagnosis or syndromic surveillance systems might first detect an anthrax outbreak based on early symptomatic cases, the entire distribution determines the efficacy of medical intervention-which is determined by the speed of the prophylaxis campaign relative to the incubation period-and the right tail of the distribution influences the recommended duration for antibiotic treatment.