The effect of the polymerized bovine haemoglobin solution, Hb-200, on endothelial function in isolated arterial rings from rats

Haemoglobin-based oxygen carriers have been developed as 'blood substitutes'. Early cross-linked haemoglobins caused marked vasoconstriction, however, polymerized haemoglobin solutions, such as the bovine product haemoglobin glutamer-200 (bovine) (Hb-200), are said to have lesser vascular effects. The aim of this study was to quantify the effect of Hb-200 on isolated rat arterial rings. The actions of Hb-200 were investigated using rings of aorta and second-order mesenteric arteries from female Wistar rats. The arterial rings were mounted for isometric tension recording. Addition of Hb-200 (1 microM) to arterial rings, precontracted with phenylephrine (50-70% maximum phenylephrine-induced tone), resulted in vasoconstriction. Addition of Hb-200 to arteries precontracted with phenylephrine and relaxed with acetylcholine (1 microM) also caused contraction. Furthermore preincubation with Hb-200 (1 microM) enhanced the response to phenylephrine (1 nm to 10 microM) and impaired acetylcholine-induced relaxation (10 nm to 10 microM). Responses to Hb-200 were similar to those in response to the nitric oxide (NO) synthase inhibitor, NG-nitro-l-arginine methyl ester (L-NAME, 100 microM), alone or in combination with Hb-200. These data demonstrate that Hb-200 has a significant vasoconstrictor effect similar to L-NAME. Thus the vascular actions of Hb-200 are consistent with activity as a NO scavenger. This may have implications for the clinical use of Hb-200.     

Predicting sapstain and degrade in fallen trees following storm damage in a Pinus radiata forest

Storm damage in production forests constitutes a major source of economic loss world wide, yet the retrieval of salvageable timber remains problematic. In particular, an inability to anticipate when sapstain and degrade will appear hampers the planning of log recovery operations. A study was conducted to monitor the deterioration of fallen trees following two winter storms causing wind and snow damage in a Pinus radiata plantation forest in the upper South Island of New Zealand. Percentage sapstain, incidence of basidiomycete decay fungi, and frequency of bark beetle infestation increased, while percentage sapwood moisture content decreased, over a period of 1 year. These changes proceeded more rapidly in fallen trees that were severed at stump height, to simulate breakage, than in those that were left partially rooted. There was little beetle activity at the time of the storms, but Arhopalus ferus (Coleoptera: Cerambycidae), and Hylastes ater, Hylurgus ligniperda and Pachycotes peregrinus (Coleoptera: Curculionidae: Scolytinae), were collected in flight traps during the following spring and summer. The predominant fungal species associated with sapstain was Diplodia pinea, while Ophiostoma piceae and Grosmannia huntii were isolated near the end of the period. The main decay fungi obtained were Phlebiopsis gigantea, Stereum sanguinolentum, and Schizophyllum commune. A generalized linear mixed model was constructed to predict the development of sapstain in fallen trees for conditions prevailing during the study after a storm at the same time of year. According to the model, a 10 m long butt log of 22 cm mid length diameter will have minimal stain (<10% of the cross sectional area affected) when cut from severed stems up to 4 months after the storm; if taken from still-rooted trees this period will extend to 1 year. However, because of large between-tree variation, economically productive log recovery will also depend on the proportion of trees that lie below an acceptable sapstain threshold. Further research is needed to determine regional and seasonal influences on the development of sapstain in fallen trees.     

Changes in the Doppler waveform of the ovine femoral artery following infusion of vasoactive agents: a preliminary study

The aim of this study was to investigate whether femoral artery pulsatility index (PI) can be used as an indicator of vasomotor tone in the digit of an ungulate species by measuring the change in PI induced by infusion of vasoactive agents in halothane-anaesthetised sheep. Intra-arterial infusion of the vasoconstrictor phenylephrine (9 microg min(-1)) tended to increase waveform PI (3.89-6.24, n=4, P=0.100). Infusion of a low dose (3 microg min(-1)) of the vasodilator sodium nitroprusside did not alter femoral artery PI, however infusion of a higher dose (30 microg min(-1)) tended to increase PI (5.39-6.70, n=5, P=0.059). During these studies heart rate, mean ABP and p(a)CO(2) did not change significantly. The tendency for PI to increase in response to vasodilation was unexpected and the mechanism involved is unclear. It appears that femoral artery PI cannot be used to predict vasomotor tone in the digit of the anaesthetised sheep.     

The impact of stratospheric ozone recovery on the Southern Hemisphere westerly jet

In the past several decades, the tropospheric westerly winds in the Southern Hemisphere have been observed to accelerate on the poleward side of the surface wind maximum. This has been attributed to the combined anthropogenic effects of increasing greenhouse gases and decreasing stratospheric ozone and is predicted to continue by the Intergovernmental Panel on Climate Change/Fourth Assessment Report (IPCC/AR4) models. In this paper, the predictions of the Chemistry-Climate Model Validation (CCMVal) models are examined: Unlike the AR4 models, the CCMVal models have a fully interactive stratospheric chemistry. Owing to the expected disappearance of the ozone hole in the first half of the 21st century, the CCMVal models predict that the tropospheric westerlies in Southern Hemisphere summer will be decelerated, on the poleward side, in contrast with the prediction of most IPCC/AR4 models.     

Deep-sea macroplanktonic sea cucumbers: suspended sediment feeders captured from deep submergence vehicle

Observations in situ confirm the swimming and feeding behavior in previously unreported dense assemblages of the holothurian Peniagone diaphana, at a depth of 2000 meters, off southern California. Proximate analysis of captured specimens indicates that this organism may represent a numerically significant, but low organic content member of many near-bottom deep-sea communities.     

Assembly of cell regulatory systems through protein interaction domains

The sequencing of complete genomes provides a list that includes the proteins responsible for cellular regulation. However, this does not immediately reveal what these proteins do, nor how they are assembled into the molecular machines and functional networks that control cellular behavior. The regulation of many different cellular processes requires the use of protein interaction domains to direct the association of polypeptides with one another and with phospholipids, small molecules, or nucleic acids. The modular nature of these domains, and the flexibility of their binding properties, have likely facilitated the evolution of cellular pathways. Conversely, aberrant interactions can induce abnormal cellular behavior and disease. The fundamental properties of protein interaction domains are discussed in this review and in detailed reviews on individual domains at Science's STKE at http://www.sciencemag.org/cgi/content/full/300/5618/445/DC1.