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Determine if D-methionine (D-met) rescue prevents temporary threshold shift (TTS) from steady-state or impulse noise and determine D-met's impact on serum and cochlear antioxidant levels. D-met at 50, 100 or 200 mg/kg/doses were administered 0, 6 and 18 hours-post noise. ABRs at baseline and 24 hours post-noise measured TTS. Serum (SOD, CAT, GR, GPx) and cochlear (GSH, GSSG) antioxidant levels measured physiological influence. Three control groups, with impulse or steady-state or without noise, were saline-injected. Ten Chinchillas/group. D-met rescue did not significantly reduce TTS or impact serum CAT, SOD, GPx or GR levels vs. noise-exposed control groups, but TTS was greater in all groups relative to no-noise controls. D-met significantly elevated CAT at 50 mg/kg vs. steady-state controls and SOD at 200 mg/kg vs. impulse noise controls. D-met significantly reduced cochlear GSH/GSSG ratios in the 100 mg/kg D-met group vs. impulse noise controls. While D-met rescue has reduced permanent threshold shift in previous studies, it did not reduce TTS in this study. However, D-met rescue did alter selective serum and cochlear oxidative state changes 24 hours post-noise relative to controls. Results demonstrate TTS studies do not always predict PTS protection in otoprotectant experimental designs. [ABSTRACT FROM AUTHOR]

Objective: This exploratory Phase 2 clinical trial is the first determining safety and efficacy of oral D-methionine (D-met) in reducing cisplatin-induced ototoxicity. Design: Randomised parallel double-blind placebo-controlled exploratory Phase 2 study. Study samples: Fifty adult cancer patients received oral D-met or placebo before each cisplatin dose. Physical examination, blood collection and audiometry occurred at baseline and subsequent visits plus post-treatment audiometry. After attrition, final analysis included 27 patients. Results: Significant treatment group by ear and time (baseline vs. post-treatment) interactions occurred at 10 kHz and 11.2 kHz. Placebo and D-met groups differed in threshold shift for left ear at 11.2 kHz (mean difference = 22.97 dB [9.59, 36.35]). Averaging across ears, placebo group showed significant threshold shifts from baseline to post-treatment at 10 kHz (mean shift= −13.65 dB [−21.32,−5.98]), 11.2 kHz (−16.15 dB [−25.19,−7.12]), and 12.5 kHz (−11.46 dB [−19.18,−3.74]) but not 8 kHz (−8.65 dB [−17.86, 0.55]). The D-met group showed no significant threshold shifts (8 kHz: −1.25 dB [−7.75, 5.25]; 10 kHz:−3.93 dB [−8.89, 1.03]; 11.2 kHz:−4.82 dB [−11.21, 1.57]; 12.5 kHz:−3.68 dB [−11.57, 4.21]). Side effects did not significantly differ between groups. Conclusion: Oral D-met reduces cisplatin-induced ototoxicity in humans. [ABSTRACT FROM AUTHOR]

An extensive, well-preserved, Late Jurassic (c. 150 Ma) geothermal system at San Agustin farm in the Deseado Massif, Patagonia, Argentina, is described. This deposit, along with others previously known from the same region, partially fills a considerable gap between Cenozoic and scattered Palaeozoic hot spring localities reported worldwide. The San Agustin deposit is novel because it represents a large (1.4 [km.sup.2]) and nearly complete geothermal landscape. Siliceous hot spring facies, both subaerial and subaqueous, are exposed side by side in their original spatial and geological context, set amongst intrusive rhyolite domes and fluviolacustrine sediments. The Jurassic hot springs have preserved an entire local ecosystem containing microbes, arthropods, gastropods and plants exhibiting Lagerstatten-style preservation. Plant preservation, in particular, ranges from decayed litter, to seedling sprouts, and to dense stands in life orientation with intact anatomy. The San Agustin deposit shares some ecological, taphonomic and sedimentological characteristics with modern hot springs. As it formed in a pre-angiosperm world, it is akin to the famous hot spring-related Devonian Rhynie cherts of Scotland. It differs in having excellent exposure, and thus will probably contribute to a better understanding of biosignal preservation in extreme environments in the geological record. doi: 10.1144/0016-76492009-109

Silicified rocks at La Marciana farm, Deseado Massif, Argentinean Patagonia, represent an ancient hot-spring discharging into an active fluvial setting. Their fortuitous burial-erosion history and minimal post-depositional structural modification provide an unparalleled view of a complete, exhumed, late Jurassic geothermal landscape, and thus an opportunity to illuminate hot-spring geological context and palaeoenvironmental gradients. Geological mapping, stratigraphy and petrography revealed hydrothermal eruption events, the spring vent source, structural relationships, dimensions of the discharge apron, and hot-spring facies distributions. Remarkable similarities to Quaternary analogues from the Taupo Volcanic Zone, New Zealand, and Yellowstone National Park, USA, are apparent with respect to scale, spatial distribution of facies, and types of microbial and other palaeoenvironmentally significant fabrics. Keywords: Hot-springs, siliceous sinter, microbial fossils, Jurassic, Argentina.

Siliceous sinters form where nearly neutral pH, alkali chloride waters discharge at the surface ([less than or equal to]100 [degrees]C). They may preserve biogenic and abiogenic material and therefore archive paleoenvironmental settings. Freshly precipitated sinters undergo diagenesis through a five-step series of silica mineral phase changes, from opal-A to opal-A/CT to opal-CT to opal-C to quartz. Transformation rates vary among sinters because postdepositional conditions can accelerate or retard diagenesis, meanwhile preserving or destroying biosignals. We monitored alteration and diagenesis of newly precipitated, filamentous microbe-rich sinter during a two-year field experiment, where sinter was suspended inside a fumarole at Orakei Korako, Taupo volcanic zone, New Zealand. Patchy and complex diagenesis resulted from changes in environmental conditions, including variations in temperature, pH, and the intermittent deposition of sulfur. Throughout the experiment, opal-A was dissolved by acidic steam condensate, and reprecipitated locally. Quartz crystals grew on the sinter surface within 21 weeks. Previous reports of transformation rates from opal to quartz are on the order of thousands of years in duration. Thus, our results show that fumarolic overprinting accelerates diagenesis. Microbial preservation was not favorable because primary filamentous fabrics were obscured by deposition of opal-A microspheres, smooth silica infill, and sulfur. If ancient hydrothermal systems were among the likely places where early life flourished, it is necessary to distinguish between depositional features and those inherited during diagenesis. This near--real time experiment enabled observations on environmental controls of diagenetic change in silica minerals and illustrated the variability of conditions that can occur in nature during this complex process. Keywords: diagenesis, hot spring, sinter, microbial filaments, opal-A, quartz, fumarole, organomineral, biomineral, silica.

In an effort to construct a framework for understanding leadership development (LD), this paper examines the available evidence regarding exactly what organizations attempt to develop under the rubric of LD, [...]

Research has been conducted on viral transcriptional activator c-Jun-KIX domain complex. The structural; study of this complex has been carried out and the results demonstrate that Kix binding mode is different to the mechanisms involved in CRE response element binding domain.

Research demonstrates the association of complementing polar groups with buried and surface positions of proteins in protein folding as exemplified by a two-stranded coiled-coil design of the ACID-p1/BASE-p1 heterodimer. Data indicate that position-a Lys residues and Lys-Glu polar interactions impart a high level of structural feature to the heterodimer.

Research shows the effects of position 'a' buried Lys residues on coiled-coil oligomerization are dependent on the amino acid residues in close proximity. The electrostatic destabilization of the Fos homodimer is diminished by switching to oligomerization aided by a single buried Lys residue.