Effect of adrenaline on glucose kinetics during exercise in adrenalectomised humans

1. The role of adrenaline in regulating hepatic glucose production and muscle glucose uptake during exercise was examined in six adrenaline deficient, bilaterally adrenalectomised humans. Six sex and age matched healthy individuals served as controls (CON).

2. Adrenalectomised subjects cycled for 45 min at 68 ± 1% maximum pulmonary Oμ uptake (VOμ,max), followed by 15 min at 84 ± 2% VOμ,max without (−ADR) or with (+ADR) adrenaline infusion, which elevated plasma adrenaline levels (45 min, 4·49 ± 0·69 nmol l¢; 60 min, 12·41 ± 1·80 nmol l¢; means ± s.e.m.). Glucose kinetics were measured using [3_ÅH]glucose.

3. Euglycaemia was maintained during exercise in CON and −ADR, whilst in +ADR plasma glucose was elevated. The exercise induced increase in hepatic glucose production was similar in +ADR and −ADR; however, adrenaline infusion augmented the rise in hepatic glucose production early in exercise. Glucose uptake increased during exercise in +ADR and −ADR, but was lower and metabolic clearance rate was reduced in +ADR.

4. During exercise noradrenaline and glucagon concentrations increased, and insulin and cortisol concentrations decreased, but plasma levels were similar between trials. Adrenaline infusion suppressed growth hormone and elevated plasma free fatty acids, glycerol and lactate. Alanine and â_hydroxybutyrate levels were similar between trials.

5. The results demonstrate that glucose homeostasis was maintained during exercise in adrenalectomised subjects. Adrenaline does not appear to play a major role in matching hepatic glucose production to the increase in glucose clearance. In contrast, adrenaline infusion results in a mismatch by simultaneously enhancing hepatic glucose production and inhibiting glucose clearance.

Must Dewey and Kierkegaard’s inquiry for world peace be violent?

Amongst the many aims of education, surely the pursuit of global peace must be one of the most significant.The mandate of UNESCO is to pursue world peace through education by primarily promoting collaboration.The sort of collaboration that UNESCO endorses involves democratic dialogue,where various persons from differing backgrounds can come together,listen,negotiate and discuss possible ways in which peace might be pursued.While this sort of democratic dialogue with its associated free intellectual inquiry is more readily acceptable for issues dealing with problems in the realm of physical nature, it is not so easily tolerated in the realm of ethics and values. Indeed inquiry into the realm of ethics by Kierkegaard has been described by Levinas to be a form of violence. Similarly John Dewey’s work has been included in a list of the ten most harmful books by some conservatives in the United States because he promoted inquiry into morals and religion. Dewey argued against the assumption that there are two-realms—one physical and one moral.He and Kierkegaard both encouraged democratic inquiry into ethics,which is the sort of collaboration recognised by UNESCO as being necessary if we are to pursue world peace.Yet such investigations can be considered by some to be violent and harmful. It is argued here that pursuing inquiries into ethics and aims of education,while appearing to challenge the status quo, should not be construed as being violent but rather should be understood as democratic and educative.

The influence of unburnt patches and distance from refuges on post-fire bird communities

Predicting the response of faunal communities to fire presents a challenge for land managers worldwide because the post-fire responses of species may vary between locations and fire events. Post-fire recovery can occur via nucleated recovery from in situ surviving populations or by colonization from ex situ populations. Fine-scale spatial patterns in the patchiness of fires and the proximity of burnt sites to source populations may contribute to both the variability in post-fire responses and the processes by which populations recover. We examined the avifauna at recently burnt sites within extensive semi-arid shrublands of south-eastern Australia, including 72 sites < 5 years since fire and 26 sites 10 years since fire. Study sites represented a gradient of increasing distance from ‘unburnt’ vegetation (i.e. > 27 years since fire) and varied in the presence or absence of small (25–900 m2) unburnt patches of vegetation. For sites < 5 years since fire, species richness was higher at sites closer to unburnt vegetation and at sites containing unburnt patches. These patterns were no longer evident at sites of 10 years since fire. The probability of occurrence of three of seven bird species modelled decreased with increasing distance to unburnt vegetation, but this pattern was evident only at sites burnt uniformly. One species was found almost exclusively at patchily burnt sites. These results are consistent with the hypothesis that proximity to unburnt vegetation enhances post-fire occupancy, and that colonization from ex situ populations is an important process for post-fire recovery of avifauna. Additionally, small unburnt patches enhance the rapid recovery of assemblages post-fire. These patterns are important for understanding the dynamics of post-fire population recovery. We recommend that management of fire for ecological purposes should explicitly consider the role that the spatial attributes of fires play in determining the post-fire community.

Clutch size for Mediterranean loggerhead turtles (Caretta caretta)

We investigated the number of eggs laid and the total clutch volume for loggerhead turtles (Caretta caretta L.) nesting on the Greek island of Cephalonia (38° 09′ N, 20° 33′ E) during 1990. Both the number of eggs laid and clutch volume were positively related to female body size, and the mean explained variation for these relationships (36·6% and 37·7%, respectively) were not significantly different. Clutch volume decreased as the season progressed because individuals laid successively smaller clutches. The inter-nesting interval (range 15–19 days) did not significantly influence the number of eggs laid or clutch volume. For individuals seen laying more than once, female size in combination with the number of a clutch in relation to all the clutches observed for that individual, together explained 65·5% of the variation in clutch volume.

Relationships of nicotianamine and other amino acids with nickel, zinc and iron in Thlaspi hyperaccumulators

Experimental evidence suggests that nicotianamine (NA) is involved in the complexation of metal ions in some metal-hyperaccumulating plants. Closely-related nickel (Ni)- and zinc (Zn)-hyperaccumulating species were studied to determine whether a correlation exists between the Ni and Zn concentrations and NA in foliar tissues. A liquid chromatography–mass spectrometry (LC-MS) procedure was developed to quantify the NA and amino acid contents using the derivatizing agent 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate. A strong correlation emerged between Ni and NA, but not between Zn and NA. Concentrations of NA and l-histidine (His) also increased in response to higher Ni concentrations in the hydroponic solution supplied to a serpentine population of Thlaspi caerulescens. An inversely proportional correlation was found between the iron (Fe) and Ni concentrations in the leaves. Correlations were also found between Zn and asparagine. The results obtained in this study suggest that NA is involved in hyperaccumulation of Ni but not Zn. The inverse proportionality between the Ni and Fe concentrations in the leaf may suggest that Ni and Fe compete for complexation to NA.