bluuebunny/crossref_metadata_2025 huggingface dataset:
Differences between Midazolam and Propofol Sedation on Upper Airway Collapsibility Using Dynamic Negative Airway Pressure
Authors: Norton J Russell , Ward Denham S. , Karan Suzanne , Voter William A. , Palmer Linda , Varlese Anna , Rackovsky Ori , Bailey Peter
Published: May 2006

Background

Upper airway obstruction (UAO) during sedation can often cause clinically significant adverse events. Direct comparison of different drugs' propensities for UAO may improve selection of appropriate sedating agents. The authors used the application of negative airway pressure to determine the pressure that causes UAO in healthy subjects sedated with midazolam or propofol infusions.

Methods

Twenty subjects (12 male and 8 female) completed the study. After achieving equivalent levels of sedation, the subjects' ventilation, end-tidal gases, respiratory inductance plethysmographic signals, and Bispectral Index values were monitored for 5 min. Negative airway pressure was then applied via a facemask in steps of 3 cm H(2)O from -3 to -18 cm H(2)O. UAO was assessed by cessation of inspiratory airflow and asynchrony between abdomen and chest respiratory inductance plethysmographic signals.

Results

Equivalent levels of sedation were achieved with both drugs with average (+/- SD) Bispectral Index levels of 75 +/- 5. Resting ventilation was mildly reduced without any changes in end-tidal pressure of carbon dioxide. There was no difference between the drugs in the negative pressure resulting in UAO. Five female subjects and one male subject with midazolam and four female subjects and one male subject with propofol did not show any UAO even at -18 cm H(2)O. Compared with males, female subjects required more negative pressures to cause UAO with midazolam (P = 0.02) but not with propofol (P = 0.1).

Conclusions

At the mild to moderate level of sedation studied, midazolam and propofol sedation resulted in the same propensity for UAO. In this homogeneous group of healthy subjects, there was a considerable range of negative pressures required to cause UAO. The specific factors responsible for the maintenance of the upper airway during sedation remain to be elucidated.
Interaction of Propofol and Sevoflurane on Loss of Consciousness and Movement to Skin Incision during General Anesthesia
Authors: Harris Robert S. , Lazar Olga , Johansen Jay W. , Sebel Peter S.
Published: May 2006

Background

Loss of consciousness (LOC) and immobility to surgical incision seem to be mediated at different levels of the central nervous system. Pharmacologic studies of hypnotic agents have previously focused on combinations of either volatile or intravenous anesthetics. This study examined the combination of inhaled sevoflurane and intravenous propofol at these two clinically relevant anesthetic end points.

Methods

Thirty-six elective surgical patients were initially enrolled. Conditions approximating steady state were obtained for sevoflurane and target-controlled propofol infusions. Patients were sequentially evaluated for LOC (loud voice plus mild prodding) and immobility to surgical incision. The study was designed using the Dixon up-down method.

Results

The observed propofol effect target with 50% response plus sevoflurane (0.46% end-tidal concentration) was 1.2 microg/ml (95% confidence interval, 1.1-1.3 microg/ml). It was not significantly different from that predicted (1.5 microg/ml; 95% confidence interval, 1.2-1.7 microg/ml) by simple additivity. The effective plasma concentration of propofol that suppressed movement to skin incision in 50% of patients was 5.4 microg/ml (95% confidence interval, 4.8-6.0 microg/ml) plus sevoflurane (0.86%) and was not significantly different from that predicted by additivity (5.4 microg/ml; 95% confidence interval, 4.8-5.9 microg/ml). Both analyses had adequate power (90%) to detect a significant change (+/-19 to 25%) from predicted value. Repeated-measures analysis of variance identified a Bispectral Index value of 70 as the break point between those who responded at LOC or did not.

Conclusions

Propofol and sevoflurane interact in a simple additive manner to produce LOC and immobility to surgical incision, suggesting a common mechanism or a single site of action. These clinical observations are consistent with a single site of interaction at the gamma-aminobutyric acid type A receptor.
Preparation and Anesthetic Properties of Propofol Microemulsions in Rats
Authors: Morey Timothy E. , Modell Jerome H. , Shekhawat Dushyant , Grand Todd , Shah Dinesh O. , Gravenstein Nikolaus , McGorray Susan P. , Dennis Donn M.
Published: May 2006

Background

The lipophilicity of propofol has required dispersion in a soybean macroemulsion. The authors hypothesized that the anesthetic properties of propofol are preserved when reformulated as a transparent microemulsion rather than as a turbid macroemulsion and that the dose-response relation can be selectively modified by altering the microemulsion's surfactant type and concentration.

Methods

Microemulsions of propofol were formulated using purified poloxamer 188 (3%, 5%, 7%), and sodium salt of fatty acids (C(8), C(10), C(12)) in saline and characterized using ternary/binary diagrams, particle sizing, and stability upon dilution. Rats received propofol (10 mg . kg(-1) . min(-1)) as either a microemulsion or a conventional macroemulsion to determine these end points: induction (dose; stunned; loss of lash reflex, righting reflex, withdrawal to toe pinch) and recovery (recovery of lash, righting, withdrawal reflexes). After a 14-day recovery period, rats were crossed over into the opposite experimental limb.

Results

Forty-eight microemulsions (diameter, 11.9-47.7 nm) were formulated. Longer carbon chain length led to a marked increase in the volume of diluent necessary to break these microemulsions. All rats experienced anesthetic induction with successful recovery, although significantly greater doses of propofol were required to induce anesthesia with microemulsions irrespective of surfactant concentration or type than with macroemulsions. The sodium salt of C10 fatty acid microemulsion required the greatest dose and longest time for anesthetic induction.

Conclusion

Propofol microemulsions cause induction in rats similar to that from macroemulsions. The surfactant concentration and type markedly affect the spontaneous destabilization and anesthetic properties of microemulsions, a phenomenon suggesting a mechanism whereby dose-response relation can be selectively modified.
Blood Warming during Hemofiltration Can Improve Hemodynamics and Outcome in Ovine Septic Shock
Authors: Rogiers Peter , Sun Qinghua , Dimopoulos George , Tu Zizhi , Pauwels Dirk , Manhaeghe Cindy , Su Fuhong , Vincent Jean-Louis
Published: May 2006

Background

This study was designed to evaluate the effects of blood warming during hemofiltration on global and regional hemodynamics, plasma lactate, and 24-h survival during septic shock.

Methods

Twenty anesthetized and mechanically ventilated sheep underwent induction of peritonitis and, 4 h later, were treated by hemofiltration with (n = 10) or without (n = 10) blood warming.

Results

In the group without blood warming, body temperature decreased after starting hemofiltration and remained below baseline. In the other animals, body temperature stabilized at baseline level during hemofiltration and increased to a maximum of 40.8 degrees C thereafter. The group without warming experienced a decrease in blood pressure (from 90 mmHg to 38 mmHg) and cardiac output (from 4.0 l/min to 2.3 l/min). Metabolic acidosis and the increase in lactate were less marked when temperature was maintained. None of the animals without warming but all of the animals with warming survived to 16 h.

Conclusions

Differences in temperature during hemofiltration resulted in striking differences in hemodynamics, metabolic acidosis, and survival rate in this clinically relevant experimental model of septic shock.
Contrasting Effects of Colloid and Crystalloid Resuscitation Fluids on Cardiac Vascular Permeability
Authors: Jacob Matthias , Bruegger Dirk , Rehm Markus , Welsch Ulrich , Conzen Peter , Becker Bernhard F.
Published: May 2006

Background

Fluid extravasation may lead to myocardial edema and consequent reduction in ventricular function. Albumin is presumed to interact with the endothelial glycocalyx. The authors' objective was to compare the impact of different resuscitation fluids (human albumin, hydroxyethyl starch, saline) on vascular integrity.

Methods

In an isolated perfused heart model (guinea pig), Krebs-Henseleit buffer was augmented with colloids (one third volume 5% albumin or 6% hydroxyethyl starch 130/0.4) or crystalloid (0.9% saline). Perfusion pressure and vascular fluid filtration (epicardial transudate formation) were assessed at different flow rates. After global, stopped-flow ischemia (37 degrees C, 20 min), hearts were reperfused with the same resuscitation fluid additives. In a second series, the authors applied the respective perfusates after enzymatic digestion of the endothelial glycocalyx (heparinase, 10 U over 15 min).

Results

Both 5% albumin and 6% hydroxyethyl starch decreased fluid extravasation versus saline (68.4 +/- 5.9, 134.8 +/- 20.5, and 436.8 +/- 14.7 microl/min, respectively, at 60 cm H(2)O perfusion pressure; P < 0.05), the corresponding colloid osmotic pressures being 2.95, 5.45, and 0.00 mmHg. Digestion of the endothelial glycocalyx decreased coronary integrity in both colloid groups. After ischemia, a transient increase in vascular leak occurred with Krebs-Henseleit buffer containing hydroxyethyl starch and saline, but not with albumin. The authors observed no difference between intravascular and bulk interstitial colloid concentration in the steady state. Notwithstanding, electron microscopy revealed an intact endothelial glycocalyx and no interstitial edema in the albumin group.

Conclusion

Ex vivo, albumin more effectively prevented fluid extravasation in the heart than crystalloid or artificial colloid. This effect was partly independent of colloid osmotic pressure and may be attributable to an interaction of albumin with the endothelial glycocalyx.
Basal Heat Pain Thresholds Predict Opioid Analgesia in Patients with Postherpetic Neuralgia
Authors: Edwards Robert R. , Haythornthwaite Jennifer A. , Tella Prabhav , Max Mitchell B. , Raja Srinivasa
Published: May 2006

Background

A variety of analgesics have been studied in the treatment of postherpetic neuralgia, with several medications demonstrating some degree of efficacy. However, existing trials have documented large individual differences in treatment responses, and it is important to identify patient characteristics that predict the analgesic effectiveness of particular interventions. Several animal studies have indicated that reduced basal nociceptive sensitivity, in the form of relatively high heat pain thresholds, is associated with greater opioid analgesia, but this finding has not been applied to human studies of opioid treatment for chronic pain.

Methods

Using data from a previously published crossover trial of opioids and tricyclics in postherpetic neuralgia, the authors evaluated baseline thermal pain thresholds, assessed at a body site contralateral to the affected area, as a predictor of treatment responses.

Results

During opioid treatment, a greater reduction in pain and higher ratings of pain relief were observed in patients with relatively higher heat pain thresholds at baseline. Baseline pain thresholds did not predict responses to tricyclics or placebo. Interestingly, other individual-difference variables such as age and baseline pain intensity also significantly predicted opioid responses (i.e., higher baseline pain and younger age were related to greater opioid-associated pain reduction, with nearly 20% of the variance in opioid analgesia explained by these two factors).

Conclusions

These findings, which will require replication, suggest that pretreatment assessment of heat pain sensitivity might prove useful in identifying those patients most likely to respond to opioids.
Comparative Somatic and Visceral Antinociception and Neurotoxicity of Intrathecal Bupivacaine, Levobupivacaine, and Dextrobupivacaine in Rats
Authors: Muguruma Tomoko , Sakura Shinichi , Kirihara Yumiko , Saito Yoji
Published: May 2006

Background

The current study investigated whether racemic bupivacaine and its S(-)- and R(+)-enantiomers, levobupivacaine and dextrobupivacaine, differ in somatic and visceral antinociception and neurotoxicity when administered intrathecally in rats.

Methods

In experiment 1, rats intrathecally received 15 microl saline or 0.125, 0.25, 0.5, or 1% bupivacaine, levobupivacaine, or dextrobupivacaine. The tail-flick and colorectal distension tests were performed to assess somatic and visceral antinociceptive effects, respectively, for 180 min after injection. In experiment 2, rats given 0.25% anesthetic solutions were evaluated with colorectal distension-induced response in blood pressure and heart rate. In experiment 3, four groups of rats received a 1-h infusion of saline or 2.5% bupivacaine, levobupivacaine, or dextrobupivacaine. Additional rats received either 1.25% bupivacaine or levobupivacaine for 1 h. Four days after infusion, animals were assessed for persistent sensory impairment using the tail-flick test. Spinal cords and nerve roots were obtained for histologic analysis.

Results

In experiment 1, the three drugs produced similar time course effects and dose-effect relations in tail-flick latency. Colorectal distension thresholds and motor paralysis were slightly lower and less apparent, respectively, at some concentrations in rats given levobupivacaine than in those given the other agents. In experiment 2, colorectal distension-induced response in heart rate was less depressed in rats given levobupivacaine than in those given the other anesthetics. In experiment 3, three groups of rats given 2.5% anesthetic solutions developed similar significant increases in tail-flick latency and incurred similar morphologic damage. Two groups of rats receiving 1.25% anesthetic solutions were similar in functional impairment and nerve injury scores.

Conclusions

The results suggest that, when administered intrathecally in rats, bupivacaine and its R(+)- and S(-)-enantiomers are similar for somatic antinociception and neurotoxicity but slightly different in visceral antinociception and motor paralysis, in which levobupivacaine is less potent than the others.
Mitigation of Direct Neurotoxic Effects of Lidocaine and Amitriptyline by Inhibition of p38 Mitogen-activated Protein Kinase In Vitro and In Vivo
Authors: Lirk Philipp , Haller Ingrid , Myers Robert R. , Klimaschewski Lars , Kau Yi-Chuan , Hung Yu-Chun , Gerner Peter
Published: May 2006

Background

Local anesthetic-induced direct neurotoxicity (paresthesia, failure to regain normal sensory and motor function) is a potentially devastating complication of regional anesthesia. Local anesthetics activate the p38 mitogen-activated protein kinase (MAPK) system, which is involved in apoptotic cell death. The authors therefore investigated in vitro (cultured primary sensory neurons) and in vivo (sciatic nerve block model) the potential neuroprotective effect of the p38 MAPK inhibitor SB203580 administered together with a clinical (lidocaine) or investigational (amitriptyline) local anesthetic.

Methods

Cell survival and mitochondrial depolarization as marker of apoptotic cell death was assessed in rat dorsal root ganglia incubated with lidocaine or amitriptyline either with or without the addition of SB203580. Similarly, in a sciatic nerve block model, the authors assessed wallerian degeneration by light microscopy to detect a potential mitigating effect of MAPK inhibition.

Results

Lidocaine at 40 mm/approximately 1% and amitriptyline at 100 microm reduce neuron count, but coincubation with the p38 MAPK inhibitor SB203580 at 10 mum significantly reduces cytotoxicity and the number of neurons exhibiting mitochondrial depolarization. Also, wallerian degeneration and demyelination induced by lidocaine (600 mm/approximately 15%) and amitriptyline (10 mm/approximately 0.3%) seem to be mitigated by SB203580.

Conclusions

The cytotoxic effect of lidocaine and amitriptyline in cultured dorsal root ganglia cells and the nerve degeneration in the rat sciatic nerve model seem, at least in part, to be mediated by apoptosis but seem efficiently blocked by an inhibitor of p38 MAPK, making it conceivable that coinjection might be useful in preventing local anesthetic-induced neurotoxicity.
Blockade of the Complement C5a Receptor Reduces Incisional Allodynia, Edema, and Cytokine Expression
Authors: Clark J David , Qiao Yanli , Li Xiangqi , Shi Xiaoyou , Angst Martin S. , Yeomans David C.
Published: May 2006

Background

Activation of the complement system is one component of the inflammatory response. Various components of the complement system participate in killing foreign organisms, recruiting immune cells, enhancing edema, and stimulating cytokine formation. Complement-mediated enhancement of the inflammation surrounding surgical incisions may increase pain.

Methods

In these studies, the authors used a murine hind paw incisional model to study the role of the complement C5a receptor in supporting incisional inflammation. At baseline and at various time points after incision, they measured the effects of a highly selective C5a receptor antagonist on nociceptive thresholds, edema formation, and cytokine production in the skin surrounding the incision. They also measured changes in C5a receptor expression near the incisions.

Results

The once-daily injection of the C5a receptor antagonist AcF-[OPdChaWR] reduced mechanical allodynia and edema in the incised hind paw. A multiplexed cytokine assay revealed that 8 of the 18 cytokines examined showed significant increases in skin tissue abundance after incision. Distinct time courses for the patterns of elevation were seen, though some degree of resolution occurred for all cytokines within 96 h. For 7 of these 8 cytokines, the C5a receptor antagonist reduced the enhancement of expression. In addition, the authors found that the C5a receptor messenger RNA level increased 15-fold in the skin surrounding the incisions within 24 h and then slowly declined.

Conclusions

The tissue directly surrounding incisions in mouse hind paws undergoes large changes in the content of specific cytokines in addition to demonstrating edema and nociceptive sensitization. By blocking the receptor for one component of the complement system, C5a, all of these changes can be reduced. Complement receptor inhibitors may constitute a novel group of compounds useful in reducing the pain and swelling of surgical incisions.
Airway Management in Adults after Cervical Spine Trauma
Authors: Crosby Edward T. , Warltier David C.
Published: May 2006

Cervical spinal injury occurs in 2% of victims of blunt trauma; the incidence is increased if the Glasgow Coma Scale score is less than 8 or if there is a focal neurologic deficit. Immobilization of the spine after trauma is advocated as a standard of care. A three-view x-ray series supplemented with computed tomography imaging is an effective imaging strategy to rule out cervical spinal injury. Secondary neurologic injury occurs in 2-10% of patients after cervical spinal injury; it seems to be an inevitable consequence of the primary injury in a subpopulation of patients. All airway interventions cause spinal movement; immobilization may have a modest effect in limiting spinal movement during airway maneuvers. Many anesthesiologists state a preference for the fiberoptic bronchoscope to facilitate airway management, although there is considerable, favorable experience with the direct laryngoscope in cervical spinal injury patients. There are no outcome data that would support a recommendation for a particular practice option for airway management; a number of options seem appropriate and acceptable.
Prospective and Daily Measures of Acute Thoughts, Decisional Struggle, and Coping: Measurement Correspondence and the Prediction of Exercise in Young Adults
Authors: Gyurcsik Nancy C. , Johnson Elizabeth M. , Perrett Jamis J.
Published: May 2006

Information on the daily stability–variability of decision‐making social cognitions has not been obtained. Two purposes were: (1) to examine the correspondence between 1‐week prospective and daily measures of acute exercise thoughts, decisional struggle, coping frequency, and coping self‐efficacy and (2) prediction of moderate exercise. Seventy‐seven experienced exercisers (M age=22.36 years) completed a 1‐week prospective and daily measures of social cognitions. Prospective and aggregated daily acute thoughts were the only non‐correspondent measures. Aggregated daily acute thoughts were the only significant predictor of exercise (ßstandardized=.78, p<.01). Daily acute thoughts may be a determinant of moderate exercise in experienced exercisers due to the unpredictable nature of daily events, warranting attention to making daily exercise decisions.
Examination of a Measure of Racial Discrimination Among African American Adolescents1
Authors: Seaton Eleanor K.
Published: May 2006

The present study consisted of an empirical examination of the psychometric properties of the Index of Race‐Related Stress (IRRS) among 258 African American adolescents. Confirmatory factor analyses supported a 3‐component model (i.e., individual, collective/institutional, and cultural) of racial discrimination perceived by African American adolescents. The revised subscales of the IRRS were associated with another measure of racial discrimination as evidence of concurrent validity, and the subscales of the IRRS demonstrated adequate reliability. The results are consistent with previous research indicating that adolescent responses to perceived racial discrimination are distinct from adults'. Future research should consider the assessment of racial discrimination among African American adolescents to understand the relationship between perceptions of racial discrimination and indexes of mental and physical health.
Primary and Secondary Control in Achievement Settings: A Longitudinal Field Study of Academic Motivation, Emotions, and Performance1
Authors: Hall Nathan C. , Perry Raymond P. , Ruthig Joelle C. , Hladkyj Steven , Chipperfield Judith G.
Published: May 2006

The present research represents an application of Rothbaum et al.'s (1982) dual‐process model of perceived control to adaptation in achievement settings. This eight‐month longitudinal field study examined how primary and secondary control influenced end‐of‐year academic motivation (e.g., voluntary course withdrawal), emotions (e.g., stress, regret, pride), and performance (e.g., cumulative grade point average) in 703 first‐year college students. For successful students, primary control related to better performance, higher motivation, and more positive affect. For unsuccessful students, the combination of primary and secondary control resulted in optimal academic adjustment. Unsuccessful students who rely on primary at the expense of secondary control risk serious long‐term deficits in motivation and performance. These findings are discussed with respect to academic overconfidence and control‐enhancing treatments.
Ethnic Segregation and Perceived Discrimination in College: Mutual Influences and Effects on Social and Academic Life1
Authors: Levin Shana , Van Laar Colette , Foote Winona
Published: May 2006

This study examined relationships among same‐ethnicity friendships, perceptions of ethnic discrimination, and social and academic adjustment in college using a large longitudinal sample of White, Asian, Latino, and African American students. Results demonstrated that Latino students who had more in‐group friends during college exhibited reduced belonging and academic performance at the end of college. Perceived discrimination also had negative effects on Latino students' sense of belonging. For African American students, having more in‐group friends during college was related to enhanced academic commitment and motivation at the end of college. Perceiving more discrimination was also associated with enhanced academic motivation for African American students. Explanations for the divergent experiences of the two minority groups on campus are discussed.
Multiple Risk Factors for Frequent and Problem Gambling: Individual, Social, and Ecological
Authors: Welte John W. , Wieczorek William F. , Barnes Grace M. , Tidwell Marie‐Cecile O.
Published: May 2006

We analyzed data for a national U.S. telephone survey. Most likely to have gambled in the past year were those whose friends and families looked favorably on gambling, Catholics, young adults, and those who live close to a lottery outlet. Most likely to have gambled frequently in the past year were those whose friends look favorably on gambling and those who live close to a lottery outlet. Most likely to be problem gamblers were Blacks, those who smoke or who are alcohol dependent, and those who live in disadvantaged neighborhoods. The decision to gamble is influenced by social milieu and values, while risk for problem gambling is influenced by proneness to problem behaviors and by disadvantaged status. Availability of gambling influences all gambling involvement.
Future Professionals and Managers: Their Attitudes Toward Unions, Organizational Beliefs, and Work Ethic
Authors: Pesek James G. , Raehsler Rod D. , Balough Robert S.
Published: May 2006

The authors replicate and extend the research on future workers' union attitudes, organizational beliefs, and work ethic. Selected demographic and attitudinal data were collected from a sample of 644 students at a small, western Pennsylvania university. Compared to earlier research on pre‐employment predictors of union attitudes, this study is based on a much larger sample size and includes a cross‐section of majors. The results offer additional support for the family socialization process; in general, future professionals and business managers are more sympathetic to labor unions if they were children of union members. In addition, the results show that student major has a significant and systematic impact on both positive and negative union attitudes.
The MAP kinase‐encoding gene MgFus3 of the non‐appressorium phytopathogen Mycosphaerella graminicola is required for penetration and in vitro pycnidia formation
Authors: COUSIN ARNAUD , MEHRABI RAHIM , GUILLEROUX MORGANE , DUFRESNE MARIE , VAN DER LEE THEO , WAALWIJK CEES , LANGIN THIERRY , KEMA GERT H. J.
Published: May 2006

In eukaryotes, a family of serine/threonine protein kinases known as mitogen‐activated protein kinases (MAPKs) is involved in the transduction of a variety of extracellular signals and in the regulation of growth and development. We identified a MAPK‐encoding gene in Mycosphaerella graminicola strain IPO323 with high homology to the orthologous Fus3 gene of Saccharomyces cerevisiae and designated it MgFus3. Early colony development of the MgFus3 mutants during in vitro growth was similar to those of the wild‐type and ectopic controls, but at the later stages of growth MgFus3 mutants did not become melanized, showed altered polarized growth and were unable to produce aerial mycelia. The MgFus3 mutants were non‐pathogenic, and detailed microscopic analyses revealed that they failed to colonize the mesophyll tissue owing to the inability to penetrate stomata. Unlike the wild‐type strain, MgFus3 mutants were unable to differentiate pycnidia on plant‐derived media. Thus, in addition to the crucial role of MgFus3 in the regulation of penetration, it may also be involved in regulating asexual fructification. Hence, MgFus3 can be regarded as a multifunctional pathogenicity factor of M. graminicola.
Signalling pathways connecting mycotoxin production and sporulation
Authors: BRODHAGEN MARION , KELLER NANCY P.
Published: May 2006

Mycotoxin contamination of food and feed presents a serious food safety issue on a global scale, causing tremendous yield and economic losses. These toxins, produced largely by members of the generaAspergillusandFusarium, represent a subset of the impressive array of secondary metabolites produced by filamentous fungi. Some secondary metabolites are associated temporally and functionally with sporulation. InAspergillusandFusarium, sporulation and mycotoxin production are both regulated by G protein signalling pathways. G protein signalling pathways commonly regulate fungal development, stress response and expression of virulence traits. In addition, fungal development is influenced by external factors. Among these are lipids, and in particular, oxylipin signals, which may be derived from either the fungus or infected seeds. Regardless of origin, oxylipins have the potential to elicit profound changes in both sporulation and mycotoxin production in the fungus. Signal transduction via G protein signalling pathways represents one mechanism by which oxylipin signals might elicit these changes. Therefore, in this review we integrate discussion of oxylipin signals and of G protein signalling cascades as regulators of fungal development.
Heat shock proteins form part of a danger signal cascade in response to lipopolysaccharide and GroEL
Authors: Davies E L , Bacelar M M F V G , Marshall M J , Johnson E , Wardle T D , Andrew S M , Williams J H H
Published: May 2006

An increasing number of cell types, including peripheral blood mononuclear cells (PBMCs), have been demonstrated to release heat shock proteins (Hsps). In this paper we investigate further the hypothesis that Hsps are danger signals. PBMCs and Jurkat cells released Hsp70 (0.22 and 0.7 ng/106 cells, respectively) into medium over 24 h at 37°C. Release of Hsp70 was stimulated 10-fold by GroEL (P < 0.001) and more than threefold by lipopolysaccharide (LPS) (P < 0.001). Although Hsp60 could be detected in the medium of cells cultured at 37°C for 24 h, the low rates of release were due probably to cell damage. Significant release of Hsp60 was observed when Jurkat cells were exposed to GroEL (2.88 ng/106 cells) or LPS (1.40 ng/106 cells). The data are consistent with the hypothesis that Hsp70 and Hsp60 are part of a danger signalling cascade in response to bacterial infection.
Early apoptosis of monocytes contributes to the pathogenesis of systemic inflammatory response and of bacterial translocation in an experimental model of multiple trauma
Authors: Efstathopoulos N , Tsaganos T , Giamarellos-Bourboulis E J , Kaldis P , Nicolaou V , Papalois A , Koutoukas P , Papachristou G , Giamarellou H
Published: May 2006

The objective of this study was to investigate the occurrence of apoptosis of monocytes in an experimental model of multiple trauma and its probable correlation to bacterial translocation. Thirty-two rabbits were applied in three groups: A, controls; B, myotomy of the right femur; and C, myotomy and fracture of the right femur. Blood was sampled for the estimation of endotoxins [lipopolysaccharide (LPS)], tumour necrosis factor (TNF)-α, malondialdehyde (MDA) and isolation of peripheral blood mononuclear cells (PBMCs). PBMCs, derived after centrifugation over Ficoll, were incubated in flasks and apoptosis of non-adherent lymphocytes and adherent monocytes was estimated after staining for Annexin-V and flow cytometry. TNF-α of supernatants of cultured monocytes was also determined. Tissue segments were cultured after death. Median survival of groups A, B and C was > 14, > 14 and 9.00 days, respectively. Apoptosis of lymphocytes in group C was higher than group A at 2, 4 and 48 h and of monocytes in group C higher than group A at 2 and 4 hours. LPS in group C was higher than group A at 2, 4 and 48 h. Apoptosis of lymphocytes and monocytes was correlated positively with serum TNF-α and negatively with TNF-α of monocyte supernatants. Cultures of organ segments of group A were sterile. Pseudomonas aeruginosa was isolated from liver, lung and spleen in five animals in group B (45.45%) and in six in group C (54.54%). Early apoptosis of blood monocytes supervened after multiple trauma; the phenomenon was accompanied by apoptosis of blood lymphocytes and subsequent bacterial translocation.
Soil nutritional factors improve models of plant species distribution: an illustration with Acer campestre (L.) in France
Authors: Coudun Christophe , Gégout Jean‐Claude , Piedallu Christian , Rameau Jean‐Claude
Published: May 2006

Aim  To estimate the relative importance of climate and soil nutritional variables for predicting the distribution of Acer campestre (L.) in French forests.

Location  France.

Methods  We used presence/absence information for A. campestre in 3286 forest plots scattered all over France, coupled with climatic and edaphic data. More than 150 climatic variables (temperature, precipitation, solar radiation, evapotranspiration, water balance) were obtained using a digital elevation model (DEM) and a geographical information system (GIS). Six direct soil variables (pH, C/N ratio, base saturation rate, concentrations of calcium, magnesium and potassium) were available from EcoPlant, a phytoecological data base for French forests. Using a forward stepwise logistic regression technique, we derived two distinct predictive models for A. campestre; the first with climatic variables alone and the second with both climatic and edaphic variables.

Results  The distribution of A. campestre was poorly modelled when including only climatic variables. The inclusion of edaphic variables significantly improved the quality of predictions for this species, allowing prediction of patches of presence/absence within the study region.

Main conclusion  Soil nutritional variables may improve the performance of fine‐scale (grain) plant species distribution models.
Climate warming and the decline of amphibians and reptiles in Europe
Authors: Araújo M. B. , Thuiller W. , Pearson R. G.
Published: May 2006

Aim  We explore the relationship between current European distributions of amphibian and reptile species and observed climate, and project species potential distributions into the future. Potential impacts of climate warming are assessed by quantifying the magnitude and direction of modelled distributional shifts for every species. In particular we ask, first, what proportion of amphibian and reptile species are projected to lose and gain suitable climate space in the future? Secondly, do species projections vary according to taxonomic, spatial or environmental properties? And thirdly, what climate factors might be driving projections of loss or gain in suitable environments for species?

Location  Europe.

Methods  Distributions of species are modelled with four species–climate envelope techniques (artificial neural networks, generalized linear models, generalized additive models, and classification tree analyses) and distributions are projected into the future using five climate‐change scenarios for 2050. Future projections are made considering two extreme assumptions: species have unlimited dispersal ability and species have no dispersal ability. A novel hybrid approach for combining ensembles of forecasts is then used to group linearly covarying projections into clusters with reduced inter‐model variability.

Results  We show that a great proportion of amphibian and reptile species are projected to expand distributions if dispersal is unlimited. This is because warming in the cooler northern ranges of species creates new opportunities for colonization. If species are unable to disperse, then most species are projected to lose range. Loss of suitable climate space for species is projected to occur mainly in the south‐west of Europe, including the Iberian Peninsula, whilst species in the south‐east are projected to gain suitable climate. This is because dry conditions in the south‐west are projected to increase, approaching the levels found in North Africa, where few amphibian species are able to persist.

Main conclusions  The impact of increasing temperatures on amphibian and reptile species may be less deleterious than previously postulated; indeed, climate cooling would be more deleterious for the persistence of amphibian and reptile species than warming. The ability of species to cope with climate warming may, however, be offset by projected decreases in the availability of water. This should be particularly true for amphibians. Limited dispersal ability may further increase the vulnerability of amphibians and reptiles to changes in climate.
Acute Inflammatory and Neuropathic Pain in Lewis and Fischer Rats
Authors: Fecho K. , Valtschanoff J. G.
Published: May 2006

Inbred, histocompatible Lewis and Fischer 344 rats (LEW and FIS) have been used to identify an inverse relationship between hypothalamic‐pituitary‐adrenal (HPA) axis activity and susceptibility to autoimmune and chronic inflammatory disorders, with LEW showing blunted HPA axis activity and increased susceptibility toward the development of autoimmunity and chronic inflammation, and FIS showing the opposite relationship. In the present study, LEW and FIS were used to determine the relationship between HPA axis function and acute inflammatory pain (carrageenan‐induced hindpaw inflammation) and neuropathic pain (partial sciatic nerve ligation; PSNL). The results showed that carrageenan‐induced thermal and mechanical allodynia and hyperalgesia were greater in FIS than in LEW. Similarly, FIS showed more carrageenan‐induced hindpaw swelling and higher levels of myeloperoxidase (a measure of neutrophils) in the carrageenan‐inflamed hindpaw. After PSNL, LEW showed a profound mechanical allodynia and hyperalgesia, whereas mechanical sensitivity in FIS was unaltered. However, FIS, but not LEW, developed thermal allodynia and hyperalgesia after PSNL. These results provide strong evidence for a positive relationship between HPA axis activity and acute inflammatory pain. The results also support a relationship between HPA axis activity and neuropathic pain, but the relationship is complex and may depend on the pain assay.
Analysis of oxidative signalling induced by ozone in Arabidopsis thaliana
Authors: MAHALINGAM RAMAMURTHY , JAMBUNATHAN NIRANJANI , GUNJAN SAMIR KUMAR , FAUSTIN ENOCK , WENG HUA , AYOUBI PATRICIA
Published: May 2006

We are using acute ozone as an elicitor of endogenous reactive oxygen species (ROS) to understand oxidative signalling in Arabidopsis. Temporal patterns of ROS following a 6 h exposure to 300 nL L−1 of ozone in ozone‐sensitive Wassilewskija (Ws‐0) ecotype showed a biphasic ROS burst with a smaller peak at 4 h and a larger peak at 16 h. This was accompanied by a nitric oxide (NO) burst that peaked at 9 h. An analysis of antioxidant levels showed that both ascorbate (AsA) and glutathione (GSH) were at their lowest levels, when ROS levels were high in ozone‐stressed plants. Whole genome expression profiling analysis at 1, 4, 8, 12 and 24 h after initiation of ozone treatment identified 371 differentially expressed genes. Early induction of proteolysis and hormone‐responsive genes indicated that an oxidative cell death pathway was triggered rapidly. Down‐regulation of genes involved in carbon utilization, energy pathways and signalling suggested an inefficient defense response. Comparisons with other large‐scale expression profiling studies indicated some overlap between genes induced by ethylene and ozone, and a significant overlap between genes repressed by ozone and methyl jasmonate treatment. Further, analysis of cis elements in the promoters of ozone‐responsive genes also supports the view that phytohormones play a significant role in ozone‐induced cell death.
Adaptation to high salinity in poplar involves changes in xylem anatomy and auxin physiology
Authors: JUNGHANS U. , POLLE A. , DÜCHTING P. , WEILER E. , KUHLMAN B. , GRUBER F. , TEICHMANN T.
Published: May 2006

To investigate the physiological basis of salt adaptation in poplar, we compared the effect of salt stress on wood anatomy and auxin physiology of the salt‐resistant Populus euphratica and salt‐sensitive Populus × canescens. Both poplar species showed decreases in vessel lumina associated with increases in wall strength in response to salt, however, in P. euphratica at three‐fold higher salt concentrations than in P. × canescens. The predicted hydraulic conductivity of the wood formed under salt stress decreased in P. × canescens, while in P. euphratica, no significant effects of salt on conductivity and transpiration were observed. The concentration of free indole‐3‐acetic acid (IAA) decreased under salt stress in the xylem of both poplar species, but to a larger extent in P. × canescens than in P. euphratica. Only salt‐treated P. euphratica exhibited an increase in IAA‐conjugates in the xylem. Genes homologous to the auxin‐amidohydrolase ILL3 were isolated from the xylems of P. euphratica and P. × canescens. For functional analysis, the auxin‐amidohydrolase from P. × canescens was overexpressed in Arabidopsis. Transgenic Arabidopsis plants were more resistant to salt stress than the wild‐type plants. Increased sensitivity of the transgenic Arabidopsis to IAA‐Leu showed that the encoded hydrolase used IAA‐Leu as a substrate. These results suggest that poplar can use IAA‐amidoconjugates in the stem as a source of auxin to balance the effects of salt stress on auxin physiology.
13CO2 pulse‐labelling of photoassimilates reveals carbon allocation within and between tree rings
Authors: KAGAWA AKIRA , SUGIMOTO ATSUKO , MAXIMOV TROFIM C.
Published: May 2006

Post‐photosynthetic fractionation processes during translocation, storage and remobilization of photoassimilate are closely related to intra‐annual δ13C of tree rings, and understanding how these processes affect tree‐ring δ13C is therefore indispensable for improving the quality of climate reconstruction. Our first objective was to study the relationship between translocation path and phloem grain. We pulse‐labelled a branch of Larix gmelinii (Rupr.) Rupr. and later analysed the δ13C distribution in the stem. A 13C spiral translocation path closely related to the spiral grain was observed. Our second objective was to study the use of remobilized storage material for earlywood formation in spring, which is a suspected cause of the autocorrelation (correlation of ring parameters to the climate in the previous year) observed in (isotope) dendroclimatology. We pulse‐labelled whole trees to study how spring, summer and autumn photoassimilate is later used for both earlywood and latewood formation. Analysis of intra‐annual δ13C of the tree rings formed after the labelling revealed that earlywood contained photoassimilate from the previous summer and autumn as well as from the current spring. Latewood was mainly composed of photoassimilate from the current year’s summer/autumn, although it also relied on stored material in some cases. These results emphasize the need for separating earlywood and latewood for climate reconstruction work with narrow boreal tree rings.
Desiccation of the resurrection plant Craterostigma plantagineum induces dynamic changes in protein phosphorylation
Authors: RÖHRIG HORST , SCHMIDT JÜRGEN , COLBY THOMAS , BRÄUTIGAM ANNE , HUFNAGEL PETER , BARTELS DOROTHEA
Published: May 2006

Reversible phosphorylation of proteins is an important mechanism by which organisms regulate their reactions to external stimuli. To investigate the involvement of phosphorylation during acquisition of desiccation tolerance, we have analysed dehydration‐induced protein phosphorylation in the desiccation tolerant resurrection plant Craterostigma plantagineum. Several dehydration‐induced proteins were shown to be transiently phosphorylated during a dehydration and rehydration (RH) cycle. Two abundantly expressed phosphoproteins are the dehydration‐ and abscisic acid (ABA)‐responsive protein CDeT11‐24 and the group 2 late embryogenesis abundant (LEA) protein CDeT6‐19. Although both proteins accumulate in leaves and roots with similar kinetics in response to dehydration, their phosphorylation patterns differ. Several phosphorylation sites were identified on the CDeT11‐24 protein using liquid chromatography‐tandem mass spectrometry (LC‐MS/MS). The coincidence of phosphorylation sites with predicted coiled‐coil regions leads to the hypothesis that CDeT11‐24 phosphorylations influence the stability of coiled‐coil interactions with itself and possibly other proteins.
Resedimentation of cold pumiceous ignimbrite into water: facies transformations simulated in flume experiments
Authors: ALLEN S. R. , FREUNDT A.
Published: May 2006

Deposits and transport processes resulting from the resedimentation of cold, unconsolidated ignimbrite into water were simulated by flume experiments. The ignimbrite sample used was poorly sorted (σ = 2·4–3), fine ash‐rich (< 63 μm, 17–30 wt%) and included both dense lithic clasts (> 2000 kg m−3) and pumice (500 to ca 1300 kg m−3). As a result of the binding forces of the ash matrix, the experiments involved resedimentation from a steep front onto the floor (with or without an initial ramp) of the water‐filled tank under both still and wave‐generated conditions. Larger discrete collapse events were induced by oversteepening the sample front and by undercutting from wave action. The mass of the collapse and proportion of pore–space water strongly influenced the style of resedimentation and the deposits. Initial collapse events were from the top of the steep front and fell onto the floor. The largest, densest clasts were deposited as a lithic lag in a proximal sediment wedge or rolled down to a break‐in‐slope. Fine ash was transported in dilute turbidity currents, and coarse unsaturated pumice clasts floated off. Moderate collapse events generated high‐density turbidity currents, trapping pumice in the flow, causing them to saturate. These low‐density pumice clasts were easily remobilized by wave activity and passing currents and accumulated on the gentle slope at the bottom of the resedimented deposit. Large collapse events slumped, producing poorly sorted mounds similar in texture to the original starting material. As the matrix of the ignimbrite sample became saturated with water, moderate and large collapse events generated debrisflows and slurries that deposited massive, poorly sorted deposits. Furthermore, once more gentle slopes were established between the sample and deposit, small cascading grainflows deposited lithic clasts on the upper slopes and levees of pumice at the terminus of low‐relief, ash channels. The experiments show that, excluding large collapse events and debrisflows, resedimenting ignimbrite in water is effective at segregating low‐density pumice clasts from dense lithic clasts and fine ash. Experiments using fine‐ash poor ignimbrite and well‐sorted quartz sand for comparison formed an inherently unstable initial steep front that immediately collapsed by continuous grain avalanches. The grainflow deposits had textures similar to the fines‐poor starting material.
A mutation in the GTP hydrolysis site of Arabidopsis dynamin‐related protein 1E confers enhanced cell death in response to powdery mildew infection
Authors: Tang Dingzhong , Ade Jules , Frye Catherine A. , Innes Roger W.
Published: May 2006

We screened for mutants of Arabidopsis thaliana that displayed enhanced disease resistance to the powdery mildew pathogen Erysiphe cichoracearum and identified the edr3 mutant, which formed large gray lesions upon infection with E. cichoracearum and supported very little sporulation. The edr3‐mediated disease resistance and cell death phenotypes were dependent on salicylic acid signaling, but independent of ethylene and jasmonic acid signaling. In addition, edr3 plants displayed enhanced susceptibility to the necrotrophic fungal pathogen Botrytis cinerea, but showed normal responses to virulent and avirulent strains of Pseudomonas syringae pv. tomato. The EDR3 gene was isolated by positional cloning and found to encode Arabidopsis dynamin‐related protein 1E (DRP1E). The edr3 mutation caused an amino acid substitution in the GTPase domain of DRP1E (proline 77 to leucine) that is predicted to block GTP hydrolysis, but not GTP binding. A T‐DNA insertion allele in DRP1E did not cause powdery mildew‐induced lesions, suggesting that this phenotype is caused by DRP1E being locked in the GTP‐bound state, rather than by a loss of DRP1E activity. Analysis of DRP1E–green fluorescent protein fusion proteins revealed that DRP1E is at least partially localized to mitochondria. These observations suggest a mechanistic link between salicylic acid signaling, mitochondria and programmed cell death in plants.