Daily rhythms in physiology may affect the pharmacokinetics of a drug. The aim of this study was to evaluate 24-hour variation in the pharmacokinetics of the CYP3A substrate midazolam. Oral (2 mg) and intravenous (1 mg) midazolam was administered at six timepoints throughout the 24-hour period in 12 healthy volunteers. Oral bioavailability (population mean value [RSE%] of 0.28 (7.1%)) showed 24...

Latitudinal clines in circadian rhythms have consistently been described in various plant species, with the most recent examples appearing in soybean cultivars and in monkey flower natural populations. These latitudinal clines provide evidence that natural variation in circadian rhythms is adaptive, but it is still unclear what adaptive benefits this variation confers, particularly because circ...

Percentage non-toxic bait interference is currently used by local authorities to monitor brushtail possum control operations but the validity of the method has not been established. Two models have been proposed to estimate an index of possum density (possums per bait) from a log-transformation of percentage bait interference. In two trials, percentage bait interference and the density index de...

BACKGROUND Measurement of late-night salivary cortisol concentrations is increasingly used as a screening test in suspected Cushing's syndrome. Cortisol concentrations are typically extremely low in late-night samples and discordant assay-specific reference ranges have been reported. Therefore, the aim of our study was to assess the analytical performance of the first automated cortisol immunoa...

BACKGROUND Variation in circadian rhythms and nocturnality may, hypothetically, be related to or independent of genetic variation in photoperiodic mediation of seasonal changes in physiology and behavior. We hypothesized that strain variation in photoperiodism between photoperiodic F344 rats and nonphotoperiodic Harlan Sprague Dawley (HSD) rats might be caused by underlying variation in clock f...

UNLABELLED The aim of this study was to determine whether the amount of growth response to mechanical compression and the underlying mechanism differed with night-time or day-time loading, relative to full time loading. Mechanical compression (nominally 0.1 MPa stress) was applied across tibial and tail vertebral growth plates of growing Sprague-Dawley rats. Four groups of animals were tested: ...

It has been demonstrated that cytokine activities are under neuroendocrine control, recently mainly exerted by the pineal gland through the circadian secretion of its main hormone melatonin (MLT). It is mainly released during the night, but at present it is still unclear which relation exists between MLT and the circadian secretion of cytokines. This study was performed to evaluate the circadia...

PURPOSE This study was designed to determine whether the amount of endochondral growth response to mechanical compression and the underlying growth mechanism differed with night-time or day-time loading, relative to full-time loading. METHODS Mechanical compression (nominally 0.1 MPa stress) was applied across tibial and tail vertebral growth plates of growing Sprague-Dawley rats. Four groups...

Increased atmospheric [CO2] could theoretically lead to increased forest productivity (‘CO2 fertilization’). This mechanism was hypothesized as a possible explanation for biomass increases reported from tropical forests in the last 301 years. We used unique long-term records of annually measured stands (eighteen 0.5 ha plots, 10 years) and focal tree species (six species, 24 years) to assess th...