Endotoxemia increases relative perfusion to dorsal-caudal lung regions.

Changes in the spatial distribution of perfusion during acute lung injury and their impact on gas exchange are poorly understood. We tested whether endotoxemia caused topographical differences in perfusion and whether these differences caused meaningful changes in regional ventilation-to-perfusion ratios and gas exchange. Regional ventilation and perfusion were measured in anesthetized, mechanically ventilated pigs in the prone position before and during endotoxemia with the use of aerosolized and intravenous fluorescent microspheres. On average, relative perfusion halved in ventral and cranial lung regions, doubled in caudal lung regions, and increased 1.5-fold in dorsal lung regions during endotoxemia. In contrast, there were no topographical differences in perfusion before endotoxemia and no topographical differences in ventilation at any time point. Consequently, endotoxemia increased regional ventilation-to-perfusion ratios in the caudal-to-cranial and dorsal-to-ventral directions, resulting in end-capillary PO2 values that were significantly lower in dorsal-caudal than ventral-cranial regions. We conclude that there are topographical differences in the pulmonary vascular response to endotoxin that may have important consequences for gas exchange in acute lung injury.     

A protocol for micropropagation of Alpinia galanga

Emerging buds of rhizome of Alpinia galanga Willd produced shoots and roots simultaneously when cultured in MS medium supplemented with kinetin 3.0 mg l^-1. Each explanted shoot bud produced 8 shoots in average and roots simultaneously within 8 weeks. Shoot proliferation could be continued even after a year by transferring each divided shoot explant to the same medium. Regenerated plantlets could be sucessfully transferred to soil where they grew well within 10–12 weeks with 80% survivality. This revised version was published online in June 2006 with corrections to the Cover Date.     

Above- and Below-ground Production of Young Scots Pine (Pinus sylvestris L.) Trees after Three Years of Growth in the Field under Elevated CO2

Scots pine (Pinus sylvestris L.) seedlings were grown for 3years in the ground in open top chambers and exposed to twoconcentrations of atmospheric CO₂(ambient or ambient + 400 µmol mol^-1) without addition of nutrients and water. Biomassproduction (above-ground and below-ground) and allocation, aswell as canopy structure and tissue nitrogen concentrationsand contents, were examined by destructive harvest after 3 years.Elevated CO₂increased total biomass production by 55%, reducedneedle area and needle mass as indicated, respectively, by lowerleaf area ratio and leaf mass ratio. A relatively smaller totalneedle area was produced in relation to fine roots under elevatedCO₂. The proportion of dry matter in roots was increased byelevated CO₂, as indicated by increased root-to-shoot ratioand root mass ratio. Within the root system, there was a significantshift in the allocation towards fine roots. Root litter constituteda much higher fraction of fine roots in trees grown in the elevatedCO₂than in those grown in ambient CO₂. Growth at elevated CO₂causeda significant decline in nitrogen concentration only in theneedles, while nitrogen content significantly increased in branchesand fine roots (with diameter less than 1 mm). There were nochanges in crown structure (branch number and needle area distribution).Based upon measurements of growth made throughout the 3 years,the greatest increase in biomass under elevated CO₂took placemainly at the beginning of the experiment, when trees grownin elevated CO₂had higher relative growth rates than those grownunder ambient CO₂; these differences disappeared with time.Symptoms of acclimation of trees to growth in the elevated CO₂treatmentwere observed and are discussed. Copyright 2000 Annals of BotanyCompany Elevated CO₂, Pinus sylvestris, biomass production, allocation, fine roots, root litter, crown structure, nitrogen, C/N ratio     

Human Discrimination of the Angular Velocity of the Vertical Movement of an Acoustic Image in Opposite Directions

The discrimination of the angular velocity of ventrodorsal and dorsoventral movement of an acoustic image was studied in nine test subjects. The experiments were performed using an apparent movement produced by consecutive activation of loudspeakers located along an arc in the vertical plane. The differential thresholds were measured by the minimum increment method. As the velocity of an acoustic image movement in opposite directions increased, the values of its mean absolute differential thresholds increased monotonically. Regression lines plotted by linear approximation of these values did not differ significantly.     

The role of Asn14 in the stability and conformation of the reactive-site loop of winged bean chymotrypsin inhibitor: crystal structures of two point mutants Asn14-->Lys and Asn14-->Asp.

A double-headed chymotrypsin inhibitor, WCI, from winged bean seeds was cloned for structural and biochemical studies. The inhibitor was subjected to two point mutations at a conserved position, Asn14. This residue, known to have a pivotal role in stabilizing the first reactive-site loop (Gln63-Phe68) of the inhibitor, is highly conserved in the sequences of the other members of Kunitz (STI) family as well as in the sequences of Kazal family of serine protease inhibitors. The mutants, N14K and N14D, were subjected to biochemical assay and their characteristics were compared with those of the recombinant inhibitor (rWCI). Crystallographic studies of the recombinant and the mutant proteins are discussed. These studies were primarily aimed at understanding the importance of the protein scaffolding towards the conformational rigidity of the reactive-site loop. Our analysis reveals that, as the Lys14 side chain takes an unusual fold in N14K and the Asp14 side chain in N14D interacts with the loop residues by water-mediated hydrogen bonds, the canonical conformation of the loop has remained effectively intact in both the mutant structures. However, minor alterations such as a 2-fold increase in the inhibitory affinity towards the cognate enzyme were observed.