bluuebunny/crossref_metadata_2025 huggingface dataset:
QT Interval Measurement
Authors: Charbit Beny , Samain Emmanuel , Merckx Paul , Funck-Brentano Christian
Published: January 2006

Background

Assessment of repolarization duration is often recommended to avoid administration of QT-prolonging drugs in patients with prolonged QTc interval, a frequent situation in the postoperative period. Bazett QT correction inappropriately increases QTc when heart rate is increased, and the use of the Fridericia formula may avoid a falsely prolonged QTc interval. The authors assessed automatic QT interval measurement to detect prolonged QTc interval (women >450 ms; men >440 ms) in the postoperative setting.

Methods

Automatic and manual electrocardiograms were performed in 108 patients after anesthesia. Automatic electrocardiographic measurement used the Bazett formula. Manual measurements were made from each electrocardiogram and used as the reference. Agreement between the two methods was analyzed. Bazett and Fridericia QT corrections were compared in this population.

Results

Agreement between automatic and manual measurements was low. The Fridericia correction, but not the Bazett correction, was independent from heart rate and allowed adequate QT correction. Sensitivity of automatic measurements to detect prolonged QTc-Bazett interval was 54%. Automatic QTc-Bazett interval less than 430 ms ruled out a manual prolonged QTc interval. When automatic QTc-Bazett was greater than 430 ms, this value was converted according to Fridericia. Automatic QTc-Fridericia greater than 430 ms identified all patients with prolonged manual QTc with a negative predictive error of 0% (95% confidence interval, 0-7%). QTc-Fridericia can be approximated by respectively adding or subtracting 5% to the uncorrected QT for each increase or decrease by 10 beats/min in heart rate from 60 beats/min.

Conclusions

Automatic QTc-Bazett measurement, if abnormal, associated with calculation of QTc-Fridericia reliably identifies patients in whom manual QTc measurement must be performed to confirm postoperative prolonged QTc interval.
Effects of General Anesthesia on Anandamide Blood Levels in Humans
Authors: Schelling Gustav , Hauer Daniela , Azad Shahnaz Christina , Schmoelz Martin , Chouker Alexander , Schmidt Michael , Hornuss Cyrill , Rippberger Markus , Briegel Josef , Thiel Manfred , Vogeser Michael
Published: January 2006

Background

The endocannabinoid system includes G-protein-coupled cannabinoid receptors, the endocannabinoids N-arachidonoylethanolamine (anandamide) and 2-arachidonoylglycerol, and multiple enzymes involved in the biosynthesis and degradation of endocannabinoids, including the anandamide metabolizing enzyme fatty acid amide hydrolase. Endocannabinoids play an important role in the physiologic control of sleep, pain processing, and emesis. The authors therefore investigated the effects of general anesthesia on the endocannabinoid system in humans.

Methods

The authors measured whole blood levels of anandamide in 12 patients after induction of general anesthesia with etomidate (an agent shown to have no effect on anandamide levels) and maintenance of anesthesia with the volatile agent sevoflurane as well as in 12 patients undergoing total intravenous anesthesia with propofol, a known inhibitor of fatty acid amide hydrolase in the mouse brain. Anandamide levels were measured using high-performance liquid chromatography-tandem mass spectrometry at four time points (before and at 10, 20, 30, and 40 min after induction of anesthesia).

Results

Patients of the sevoflurane group showed a significant decline in anandamide levels from induction of anesthesia to 40 min after induction, whereas anandamide levels in patients of the propofol group remained unchanged (type III sum of squares = 1725.66, F = 162.60, P < 0.001, repeated-measures analysis of variance).

Conclusion

General anesthesia influences the endocannabinoid system in a drug-dependent way, which may explain side effects of general anesthetics such as psychomimetic and antiemetic properties of propofol and the high incidence of postoperative nausea and vomiting after volatile anesthetics. These findings suggest new targets for anesthetic drug development.
Expansion of Gas Bubbles by Nitrous Oxide and Xenon
Authors: Benavides Rodrigo , Maze Mervyn , Franks Nicholas P.
Published: January 2006

Background

Nitrous oxide is well known to expand gas bubbles trapped in enclosed spaces and is contraindicated in situations where this may occur. Xenon, an anesthetic gas with similar physical properties to nitrous oxide, is also likely to expand gas bubbles, and it has been predicted that microbubbles in the circulation may expand dramatically when exposed to xenon. Because of the possibility that xenon will be used during cardiopulmonary bypass surgery, a procedure that is likely to introduce microbubbles into the circulation, the authors reinvestigated the extent to which xenon expands gas bubbles in aqueous solution.

Methods

Gas bubbles of either air or oxygen were formed in an aqueous solution, and their size was monitored using optical microscopy when they were exposed to a rapidly flowing solution of xenon, nitrous oxide, or a xenon-oxygen mixture.

Results

Both nitrous oxide and xenon rapidly expanded air bubbles, although nitrous oxide caused a much larger expansion. The observed expansion was not greatly dependent on the initial size of the bubble but was significantly greater at lower temperatures. Under conditions relevant to cardiopulmonary bypass surgery (50% xenon-50% oxygen, 30 degrees C), the increase in diameter was modest (9.7 +/- 0.8%).

Conclusions

Although xenon does expand small air and oxygen bubbles, the extent to which this occurs under clinically relevant conditions of concentration and temperature is modest.
Increased Expression of Cyclooxygenase and Nitric Oxide Isoforms, and Exaggerated Sensitivity to Prostaglandin E2, in the Rat Lumbar Spinal Cord 3 Days after L5–L6 Spinal Nerve Ligation
Authors: O’Rielly Darren D. , Loomis Christopher W.
Published: January 2006

Background

Spinal prostaglandins seem to be important in the early pathogenesis of experimental neuropathic pain. Here, the authors investigated changes in the expression of cyclooxygenase and nitric oxide synthase (NOS) isoforms in the lumbar, thoracic, and cervical spinal cord and the pharmacologic sensitivity to spinal prostaglandin E2 (PGE2) after L5-L6 spinal nerve ligation (SNL).

Methods

Male Sprague-Dawley rats, fitted with intrathecal catheters, underwent SNL or sham surgery 3 days before experimentation. Paw withdrawal threshold was monitored for up to 20 days. Immunoblotting, spinal glutamate release, and behavioral testing were examined 3 days after SNL.

Results

Allodynia (paw withdrawal threshold < or = 4 g) was evident 1 day after SNL and remained stable for 20 days. Paw withdrawal threshold was unchanged (P > 0.05) from baseline (> 15 g) after sham surgery except for a small but significant decrease on day 20. Cyclooxygenase 2, neuronal NOS, and inducible NOS were significantly increased in the ipsilateral lumbar dorsal horn after SNL. Expression in the contralateral dorsal horn and ventral horns (lumbar segments) or bilaterally (thoracic and cervical segments) was unchanged from sham controls. This was accompanied by a significant decrease in both the EC50 of PGE2-evoked glutamate release and the ED50 of PGE2 on brush-evoked allodynia. Enhanced sensitivity to PGE2 was localized to lumbar segments of SNL animals and attenuated by SC-51322 or S(+)-ibuprofen, but not R(-)-ibuprofen (100 mum).

Conclusion

The increased expression of cyclooxygense-2, neuronal NOS, and inducible NOS and the enhanced sensitivity to PGE2 in spinal segments affected by SNL support the hypothesis that spinal prostanoids play an early pathogenic role in experimental neuropathic pain.
Amino terminus of the SARS coronavirus protein 3a elicits strong, potentially protective humoral responses in infected patients
Authors: Zhong Xiaofen , Guo Zufeng , Yang Huanghao , Peng Lisheng , Xie Yong , Wong Tin-Yau , Lai Sik-To , Guo Zhihong
Published: January 2006

The 3a protein of severe acute respiratory syndrome (SARS)-associated coronavirus is expressed and transported to the plasma membrane in tissue cells of infected patients. Its short N-terminal ectodomain was found to elicit strong humoral responses in half of the patients who had recovered from SARS. The ectodomain-specific antibodies from the convalescent-phase plasma readily recognized and induced destruction of 3a-expressing cells in the presence of the human complement system, demonstrating their potential ability to provide immune protection by recognizing and eliminating SARS coronavirus-infected cells that express the target protein. In addition, when coupled to a carrier protein, the ectodomain peptide elicited 3a-specific antibodies in mice and rabbit at high titres. These results showed that the N terminus of the 3a protein is highly immunogenic and elicits potentially protective humoral responses in infected patients. Therefore, the short extracellular domain may be a valuable immunogen in the development of a vaccine for infectious SARS.
Biological, antigenic and phylogenetic characterization of the flavivirus Alfuy
Authors: May Fiona J. , Lobigs Mario , Lee Eva , Gendle Debra J. , Mackenzie John S. , Broom Annette K. , Conlan James V. , Hall Roy A.
Published: January 2006

Alfuy virus (ALFV) is classified as a subtype of the flavivirus Murray Valley encephalitis virus (MVEV); however, despite preliminary reports of antigenic and ecological similarities with MVEV, ALFV has not been associated with human disease. Here, it was shown that ALFV is at least 104-fold less neuroinvasive than MVEV after peripheral inoculation of 3-week-old Swiss outbred mice, but ALFV demonstrates similar neurovirulence. In addition, it was shown that ALFV is partially attenuated in mice that are deficient in α/β interferon responses, in contrast to MVEV which is uniformly lethal in these mice. To assess the antigenic relationship between these viruses, a panel of monoclonal antibodies was tested for the ability to bind to ALFV and MVEV in ELISA. Although the majority of monoclonal antibodies recognized both viruses, confirming their antigenic similarity, several discriminating antibodies were identified. Finally, the entire genome of the prototype strain of ALFV (MRM3929) was sequenced and phylogenetically analysed. Nucleotide (73 %) and amino acid sequence (83 %) identity between ALFV and MVEV confirmed previous reports of their close relationship. Several nucleotide and amino acid deletions and/or substitutions with putative functional significance were identified in ALFV, including the abolition of a conserved glycosylation site in the envelope protein and the deletion of the terminal dinucleotide 5′-CUOH-3′ found in all other members of the genus. These findings confirm previous reports that ALFV is closely related to MVEV, but also highlights significant antigenic, genetic and phenotypic divergence from MVEV. Accordingly, the data suggest that ALFV is a distinct species within the serogroup Japanese encephalitis virus.
Insertion and deletion analyses identify regions of non-structural protein 5A of Hepatitis C virus that are dispensable for viral genome replication
Authors: Liu Shuanghu , Ansari Israrul H. , Das Subash C. , Pattnaik Asit K.
Published: January 2006

Hepatitis C virus (HCV) non-structural protein 5A (NS5A) plays an essential role in viral genome replication. A series of transposon-mediated insertion mutants and deletion mutants of NS5A was used to examine the colony-forming ability of HCV subgenomic replicons encoding the mutant proteins. The results reveal that two regions of NS5A can tolerate insertions: one spanning residues 240–314, which contain the interferon sensitivity-determining region (ISDR), and the other spanning residues 349–417 at the carboxy terminus. The majority of these sites also tolerated insertion of enhanced green fluorescent protein. Furthermore, replicons encoding NS5A with deletions in ISDR or in the carboxy-terminal regions were replication-competent, indicating that these regions of NS5A are not necessary for replication. Taken together, the results suggest that the central region spanning the ISDR and the carboxy-terminal region of the molecule are dispensable for the functions of NS5A in viral genome replication.
Identification and genome characterization of Heliothis armigera cypovirus types 5 and 14 and Heliothis assulta cypovirus type 14
Authors: Li Yang , Tan Li , Li Yanqiu , Chen Wuguo , Zhang Jiamin , Hu Yuanyang
Published: January 2006

Genomic characterization of Heliothis armigera cypovirus (HaCPV) isolated from China showed that insects were co-infected with several cypoviruses (CPVs). One of the CPVs (HaCPV-5) could be separated from the others by changing the rearing conditions of the Heliothis armigera larvae. This finding was further confirmed by nucleotide sequencing analysis. Genomic sequences of segments S10–S7 from HaCPV-14, S10 and S7 from HaCPV-5, and S10 from Heliothis assulta CPV-14 were compared. Results from database searches showed that the nucleotide sequences and deduced amino acid sequences of the newly identified CPVs had high levels of identity with those of reported CPVs of the same type, but not with CPVs of different types. Putative amino acid sequences of HaCPV-5 S7 were similar to that of the protein from Rice ragged stunt virus (genus Oryzavirus, family Reoviridae), suggesting that CPVs and oryzaviruses are related more closely than other genera of the family Reoviridae. Conserved motifs were also identified at the ends of each RNA segment of the same virus type: type 14, 5′-AGAAUUU…CAGCU-3′; and type 5, 5′-AGUU…UUGC-3′. Our results are consistent with classification of CPV types based on the electrophoretic patterns of CPV double-stranded RNA.
Analysis of protein–protein interactions in the feline calicivirus replication complex
Authors: Kaiser William J. , Chaudhry Yasmin , Sosnovtsev Stanislav V. , Goodfellow Ian G.
Published: January 2006

Caliciviruses are a major cause of gastroenteritis in humans and cause a wide variety of other diseases in animals. Here, the characterization of protein–protein interactions between the individual proteins of Feline calicivirus (FCV), a model system for other members of the family Caliciviridae, is reported. Using the yeast two-hybrid system combined with a number of other approaches, it is demonstrated that the p32 protein (the picornavirus 2B analogue) of FCV interacts with p39 (2C), p30 (3A) and p76 (3CD). The FCV protease/RNA polymerase (ProPol) p76 was found to form homo-oligomers, as well as to interact with VPg and ORF2, the region encoding the major capsid protein VP1. A weak interaction was also observed between p76 and the minor capsid protein encoded by ORF3 (VP2). ORF2 protein was found to interact with VPg, p76 and VP2. The potential roles of the interactions in calicivirus replication are discussed.
Neuropathogenesis of herpesvirus papio 2 in mice parallels infection with Cercopithecine herpesvirus 1 (B virus) in humans
Authors: Rogers Kristin M. , Ritchey Jerry W. , Payton Mark , Black Darla H. , Eberle R.
Published: January 2006

Cercopithecine herpesvirus 1 (monkey B virus; BV) produces extremely severe and usually fatal infections when transmitted from macaque monkeys to humans. Cercopithecine herpesvirus 16 (herpesvirus papio 2; HVP2) is very closely related to BV, yet cases of human HVP2 infection are unknown. However, following intramuscular inoculation of mice, HVP2 rapidly invades the peripheral nervous system and ascends the central nervous system (CNS) resulting in death, very much like human BV infections. In this study, the neurovirulence of HVP2 in mice was further evaluated as a potential model system for human BV infections. HVP2 was consistently neurovirulent when administered by epidermal scarification, intracranial inoculation and an eye splash. Quantitative real-time PCR, histopathology and immunohistochemistry were used to follow the temporal spread of virus following skin scarification and to compare the pathogenesis of neurovirulent and apathogenic isolates of HVP2. Apathogenic isolates were found to be capable of reaching the CNS but were extremely inefficient at replicating within the CNS. It is concluded that neurovirulent strains of HVP2 exhibit a pathogenesis in mice that parallels that observed in human BV infections and that this model system may prove useful in dissecting the viral determinants underlying the extreme severity of zoonotic BV infections.
The cytoplasmic domain of the F protein of Human respiratory syncytial virus is not required for cell fusion
Authors: Branigan Patrick J. , Day Nicole D. , Liu Changbao , Gutshall Lester L. , Melero José A. , Sarisky Robert T. , Vecchio Alfred M. Del
Published: January 2006

The cytoplasmic domains of the fusion proteins encoded by several viruses play a role in cell fusion and contain sites for palmitoylation associated with viral protein trafficking and virus assembly. The fusion (F) protein ofHuman respiratory syncytial virus(HRSV) has a predicted cytoplasmic domain of 26 residues containing a single palmitoylated cysteine residue that is conserved in bovine RSV F protein, but not in the F proteins of other pneumoviruses such as pneumonia virus of mice, human metapneumovirus and avian pneumovirus. The cytoplasmic domains in other paramyxovirus fusion proteins such as Newcastle disease virus F protein play a role in fusion. In this study, it was shown that deletion of the entire cytoplasmic domain or mutation of the single cysteine residue (C550S) of the HRSV F protein had no effect on protein processing, cell-surface expression or fusion.
Human herpesvirus 6 envelope cholesterol is required for virus entry
Authors: Huang Honglan , Li Yongmei , Sadaoka Tomohiko , Tang Huanmin , Yamamoto Takahito , Yamanishi Koichi , Mori Yasuko
Published: January 2006

In this study, the role of cholesterol in the envelope of human herpesvirus 6 (HHV-6) was examined by using methyl-β-cyclodextrin (MβCD) depletion. When cholesterol was removed from HHV-6 virions with MβCD, infectivity was abolished, but it could be rescued by the addition of exogenous cholesterol. HHV-6 binding was affected slightly by MβCD treatment. In contrast, envelope cholesterol depletion markedly affected HHV-6 infectivity and HHV-6-induced cell fusion. These results suggest that the cholesterol present in the HHV-6 envelope plays a prominent role in the fusion process and is a key component in viral entry.
Polymorphs of p-nitrophenol as studied by variable-temperature X-ray diffraction and calorimetry: comparison with m-nitrophenol
Authors: Wójcik Grażyna , Mossakowska Izabela
Published: January 2006

Crystal structures of two polymorphic forms of p-nitrophenol have been determined at several temperatures between 120 and 375 K. The thermal expansion tensor has been determined for both polymorphs. The rigid-body mean-square amplitudes of molecular translations and librations and the amplitudes of the internal torsions of the nitro group have been calculated at different temperatures. Differential scanning calorimetry was used to find the temperature and enthalpy of the polymorphic transformation. The results were compared with those recently obtained for m-nitrophenol polymorphs. Some conclusions concerning the polymorphism of p- and m-nitrophenols are presented.
Structure model for the τ(μ) phase in Al–Cr–Si alloys deduced from the λ phase by the strong-reflections approach
Authors: Zhang H. , He Z.B. , Oleynikov P. , Zou X. D. , Hovmöller S. , Kuo K. H.
Published: January 2006

There are very obvious common features in the electron diffraction patterns of the λ and τ(μ) phases in the Al–Cr–Si system. The positions of the strong reflections and their intensity distributions are similar for the two structures. The relation of the reciprocal lattices of the λ and τ(μ) phases is studied. By applying the strong-reflections approach, the structure factors of τ(μ) are deduced from the corresponding structure factors of the known λ phase. Rules for selecting reflections for the strong-reflections approach are described. Similar to that of λ, the structure of τ(μ) contains six layers stacked along the
c
axis in each unit cell. There are 752 atoms in each unit cell, 53 of them are unique. The corresponding composition of the τ(μ) model is Al3.82 − x
CrSi
x
. Simulated electron diffraction patterns from the structure model are in good agreement with the experimental ones. The arrangement of interpenetrated icosahedral clusters in the τ(μ) phase is discussed.
Neutron diffraction analysis of deuterium transfer in chiral β-thiolactam formation in the crystalline state
Authors: Hosoya Takaaki , Uekusa Hidehiro , Ohashi Yuji , Ohhara Takashi , Tanaka Ichiro , Niimura Nobuo
Published: January 2006

Since N,N-dibenzyl-1-cyclohexenecarbothioamide is photo-isomerized to the optically active β-thiolactam with the retention of the single-crystal form, the mechanism of chirality induction was identified by X-ray crystal structure analyses during the process of the reaction [Hosoya et al. (2002). Bull. Chem. Soc. Jpn, 75, 2147–2151]. In order to clarify the mechanism of hydrogen transfer in the reaction, the H atoms of the benzyl groups were replaced with deuterium atoms. The crystal structure after photoisomerization was analyzed by neutron diffraction. One of four deuterium atoms of the two benzyl groups is transferred to the C atom of the cyclohexene ring. The absolute configuration of the —C*HD— group (chiral methylene) in the photoproduct β-thiolactam revealed that the deuterium atom occupies the equatorial position. This suggests that the deuterium atom is not transferred from the benzyl group of a neighbouring molecule, but from one of the benzyl groups within the molecule.
Determination of network of residues that regulate allostery in protein families using sequence analysis
Authors: Dima Ruxandra I. , Thirumalai D.
Published: January 2006

Allosteric interactions between residues that are spatially apart and well separated in sequence are important in the function of multimeric proteins as well as single‐domain proteins. This observation suggests that, among the residues that are involved in long‐range communications, mutation at one site should affect interactions at a distant site. By adopting a sequence‐based approach, we present an automated approach that uses a generalization of the familiar sequence entropy in conjunction with a coupled two‐way clustering algorithm, to predict the network of interactions that trigger allosteric interactions in proteins. We use the method to identify the subset of dynamically important residues in three families, namely, the small PDZ family, G protein–coupled receptors (GPCR), and the Lectins, which are cell‐adhesion receptors that mediate the tethering and rolling of leukocytes on inflamed endothelium. For the PDZ and GPCR families, our procedure predicts, in agreement with previous studies, a network containing a small number of residues that are involved in their function. Application to the Lectin family reveals a network of residues interspersed throughout the C‐terminal end of the structure that are responsible for binding to ligands. Based on our results and previous studies, we propose that functional robustness requires that only a small subset of distantly connected residues be involved in transmitting allosteric signals in proteins.
On the value of information: studying changes in patch assessment abilities through learning
Authors: A. Vásquez Rodrigo , Grossi Bruno , Natalia Márquez I.
Published: January 2006

Little is known about how animals acquire and use prior information, particularly for Bayesian patch assessment strategies. Because different patch assessment strategies rely upon distinct capabilities to obtain information, we analyzed whether foragers can alter their foraging strategy when they exploit predictable patches with periodic renewal. For this, we evaluated if learning contribute to increase foraging efficiency by improving patch assessment abilities in degus (Octodon degus), a diurnal caviomorph rodent from central Chile. Single degus exploited pairs of depleting patches that were renewed daily. During the initial two days of the experiment, degus exploited patches in agreement with a fixed‐time strategy, i.e. at the population level, giving‐up densities (GUD) were not distinguishable from density‐independence (i.e. consumption proportional to initial patch densities), and richer patches were under‐exploited. After day five, degus improved significantly their assessment strategy, showing agreement with Bayesian information updating. However, on day 15 and afterwards, degus foraged patches in agreement with a prescient strategy, because GUDs across patches indicated positive density‐dependence and equalization of GUDs. Although highly variable, the GUD ratio between rich and poor patches decreased significantly throughout time. Within‐subject data showed that as subjects learned patch qualities they showed a tendency toward GUD equalization and differentiation from density‐independence. By the end of the experiment, degus allocated more time to richer patches during the initial period of each trial, and allocated similar amounts of time by the end of trials. Further, the first visit of a session was significantly biased toward the rich patch by the final days of the experiment. The results suggest that assessment abilities can change when exploiting novel but predictable patches. When degus can incorporate adequate environmental information, prior and current information may become accurate enough to make animals exploit patches efficiently.
Phenotypic plasticity in reproductive traits induced by food availability in a lacertid lizard, Takydromus septentrionalis
Authors: Du Wei‐Guo
Published: January 2006

Understanding the proximate determinants of phenotypic variations in life‐history traits can provide powerful insights into a species’ life‐history strategies. I experimentally manipulated availability of food (high vs low) to examine plasticity in the reproductive traits of northern grass lizards, Takydromus septentrionalis (Lacertidae), from eastern China. Food availability significantly affected reproductive frequency and thereby seasonal reproductive output, but had little effect on reproductive output per clutch. Low‐food females postponed reproduction and produced less clutches in the reproductive season than did high‐food females. After producing their second clutches, low‐food females were in lower body condition than the high‐food counterparts. By the end of the experiment, however, all females exhibited similar body condition. Clutch size and clutch mass differed between the first and second clutches but not between the treatments. Egg size and phenotypic traits of hatchlings (body size, morphology and locomotor performance) in T. septentrionalis did not vary significantly from first to second clutches nor between the two treatments. These results support optimal egg size (offspring) theory. Female T. septentrionalis “decide” whether or not to reproduce largely based on current energy intake; lowered feeding rates thus delay oviposition and reduce reproductive frequency. In contrast, clutch size, egg size and relative clutch mass remain unchanged.
Community structure of canopy arthropods associated toQuercus crassifolia×Quercus crassipescomplex
Authors: Tovar‐Sánchez Efraín , Oyama Ken
Published: January 2006

Quercus crassifoliaandQ. crassipesare dominant species in temperate forests of central Mexico and hybridize between each other when they occur in sympatry. Oak canopies contain a considerable portion of arthropod diversity and the hybrid zones can provide new habitats to epiphyte fauna. We tested if the establishment of hybrids in contact zones with their parental hosts increases the species diversity of canopy arthropods assuming that hybrid trees constitute new genotypes of potential new habitats to small organisms. We examined the effect of hybridization on some community structure parameters (diversity, composition, similarity and density of arthropod fauna) of canopy arthropods compared to their parental species in a hybrid zone located in central Mexico. We employed 17 leaf morphological traits and six diagnostic RAPD primers to identify parental and hybrid plants. The RAPDs marker showed unidirectional introgression towardsQ.crassifolia, and were detected hybrid (F1), backcrosses and introgression individual trees. In total, 30 oak canopies were fogged during rainy and dry season. We recognized 532 taxa of arthropods belonging to 22 orders associated with tree canopies. The taxonomic status of host‐trees may be an important factor in the arthropod community structure and that seasonality (dry and rainy) is not a factor that could modify their organization. Trees ofQ. crassipesregistered the highest densities of arthropod fauna followed by hybrid hosts (F1); trees originated by backcrosses towardsQ. crassifoliaregistered a significant less arthropod density than F1hybrids; and trees ofQ. crassifoliahad the lowest density. Hybrid plants andQ. crassipesindividuals had higher diversity (H′) of arthropods thanQ. crassifoliaplants. Hybrid plants had also more rare species in both seasons in comparison with parental species. This study suggests that hybrid oaks act as a center of biodiversity by accumulating arthropods of both parental and different species including a considerable number of rare species.
Diversity: between neutrality and structure
Authors: Pueyo Salvador
Published: January 2006

Here I present an integrated framework for species abundance distributions (SADs) that goes beyond the neutral theory without relying on complex mechanistic models. I give some general mathematical results on the relationship between SADs and their underlying dynamics, and analyse an extensive set of marine phytoplankton data in order to test the neutral theory against this broader framework.

The main theoretical and empirical results are: (i) the logseries, which is the SAD produced by simple neutral models without migration, is quite robust in response to additional factors, including some forms of niche segregation; (ii) when there is a small but significant deviation from a logseries, the SAD will generally have the form of a power law, regardless of the specific mechanisms; (iii) when the deviation is moderate, the SAD will generally have the form of a lognormal, regardless of the specific mechanisms; (iv) although in a wide range of situations neutral and non‐neutral dynamics cannot be distinguished from the SAD alone, some empirical SADs do have the fingerprint of non‐neutrality: this is the case of marine dinoflagellates, in contrast to marine diatoms, which adjust to neutral theory predictions. The results for marine phytoplankton illustrate that both neutral and non‐neutral mechanisms coexist in nature, and seem to have different weights in different groups of organisms.

In addition to the above findings, I discuss several related contributions and point out some important pitfalls in the literature.
Bayes’ theorem and its applications in animal behaviour
Authors: McNamara John M. , Green Richard F. , Olsson Ola
Published: January 2006

Bayesian decision theory can be used to model animal behaviour. In this paper we give an overview of the theoretical concepts in such models. We also review the biological contexts in which Bayesian models have been applied, and outline some directions where future studies would be useful. Bayesian decision theory, when applied to animal behaviour, is based on the assumption that the individual has some sort of “prior opinion” of the possible states of the world. This may, for example, be a previously experienced distribution of qualities of food patches, or qualities of potential mates. The animal is then assumed to be able use sampling information to arrive at a “posterior opinion”, concerning e.g. the quality of a given food patch, or the average qualities of mates in a year. A correctly formulated Bayesian model predicts how animals may combine previous experience with sampling information to make optimal decisions. We argue that the assumption that animals may have “prior opinions” is reasonable. Their priors may come from one or both of two sources: either from their own individual experience, gained while sampling the environment, or from an adaptation to the environment experienced by previous generations. This means that we should often expect to see “Bayesian‐like” decision‐making in nature.
Is delayed selfing adjusted to chemical cues of density in the freshwater snail Physa acuta?
Authors: Henry Pierre‐Yves , Vimond Ludovic , Lenormand Thomas , Jarne Philippe
Published: January 2006

Delayed selfing allows self‐fertile organisms to reproduce even in the absence of mate, and is thought to have evolved as a reproductive assurance strategy. In animal species with strong inbreeding depression, the time during which selfing should be postponed in the absence of mates (referred to as the waiting time) is predicted to have evolved as a function of inbreeding depression, resource reallocation and survival. Under the same theoretical perspective, variation in population density should trigger the evolution of a plastic adjustment of the waiting time. A condition is that individuals should be able to perceive environmental cues (e.g. chemicals) of the density of potential mates. These predictions were tested here using the hermaphroditic freshwater snail Physa acuta, based on two experiments in which rearing water was conditioned such as to manipulate the probability of mate encounter through chemical signals emitted by snails. First, a choice trial experiment showed that the exploration behaviour of individuals is sensible to chemical signals. The second experiment aimed at documenting fitness components (age at first reproduction, growth before and after reproduction, and fecundity over a three‐week period) under five treatments (20 individuals per treatment) with different water‐conditioning and access to mate. As predicted theoretically, this experiment detected the occurrence of a waiting time (11 days) and resource reallocation to growth when comparing individuals from pure water (no chemicals) and outcrossing individuals. However, the waiting time and resource reallocation to future fecundity did not increase with increasing chemical cues of conspecifics density. There is therefore no evidence that delayed selfing is plastic and adjusted according to mate encounter probability.
The role of site, habitat, seasonality and competition in determining the nightly activity patterns of psammophilic gerbils in a centrifugally organized community
Authors: Wasserberg Gideon , P. Kotler Burt , Abramsky Zvika
Published: January 2006

Major ecological forces affecting diel activity patterns include predation, competition, resource dynamics, and ambient conditions. In this work we studied if, how, and why the nocturnal activity patterns of two gerbil species differed with respect to site, habitat, season, and inter‐specific competition. The study system included two gerbil species‐Gerbillus pyramidum and G. andersoni allenbyi in a sandy landscape composed of three habitats‐shifting, semi‐stabilized, and stabilized sand habitats. Conforming to previous studies, in the semi‐stabilized sand habitat clear temporal partitioning in activity times occurred, with G. pyramidum being active earlier in the night and G. a. allenbyi being active in the later part of the night. As shown in previous studies in a different, more xeric site, removal of G. pyramidum demonstrated that this activity pattern is the result of interference competition by the latter on the former. Nocturnal activity pattern differed between habitats and seasons. Temporal partitioning occurred in the semi‐stabilized sand habitat where both gerbil species were common. In the shifting sand habitat, G. pyramidum activity pattern was similar to that in the semi‐stabilized sand habitat, but at a lower level. In the stabilized sand habitat where G. a. allenbyi occurred alone, its activity was the highest among the three habitats and was fairly constant throughout the night. Temporal partitioning occurred in the fall and early summer, but not in the early spring. The roles of predation risk, competition and resource dynamics in determining the gerbils’ temporal activity together with their implications for community structure, are discussed.
Tradeoffs between food abundance and predation danger in spatial usage of a stopover site by western sandpipers,Calidris mauri
Authors: Pomeroy Andrea C.
Published: January 2006

Foragers use a variety of anti‐predator behaviours to increase their safety from predators. While foraging, animals should alter usage within or between sites to balance the benefits of feeding with the costs of predation. I tested how the distribution of food abundance and predation danger interacts to explain spatial usage (i.e. distance from shore) by migratory western sandpipers (Calidris mauri) at Boundary Bay, British Columbia, Canada, during northward and southward migrations. At Boundary Bay there are opposing spatial gradients in the distribution of food abundance and safety from predators. Predation danger for sandpipers is high near the shoreline where there is approach cover for falcons and decreases with distance from shore. Food abundance for sandpipers declines as distance from the shoreline increases. Food and danger attributes at Boundary Bay also differ temporally, such that food abundance is higher during southward migration, and predation danger is higher during northward migration. The spatial usage by western sandpipers balances the tradeoff between the opposing spatial gradients in food and safety. For both migratory periods spatial usage of the mudflat by sandpipers is highest at distances from the shoreline where food abundance and predation danger are intermediate. During the northward migration sandpiper usage is highest between 150 and 500 m from the shoreline, and during the southward migration sandpiper usage is highest between 100 and 600 m from the shoreline. Despite temporal differences in food and danger attributes, spatial usage of the site by sandpipers does not differ between migratory periods. Understanding how the distribution of food abundance and predation danger interact to affect the within site usage by shorebirds has important implications for assessments of site quality.
Feedback structures of northern small rodent populations
Authors: Lima Mauricio , A. Berryman Alan , Chr. Stenseth Nils
Published: January 2006

Regular oscillations of northern small rodents (lemmings, voles and mice) have fascinated ecologists for decades. In particular, cycles exhibited by Fennoscandian voles have inspired population ecologists to propose several hypotheses for their underlying causes. Although there is now some agreement that the interaction with specialist predators is involved, many aspects remain enigmatic, one being the precise ecological mechanism involved in the first‐order feedback effect (i.e. direct density dependence). In this paper we evaluate the relative importance of first and second‐order negative feedback on small rodent dynamics in 64 data sets, assess the evidence of non‐linearity in the feedback structure, and look for similarities and/or differences between species and places. A clear feature of our analysis was the highly consistent pattern of first‐order dynamics across species and locations, suggesting the importance of intra‐specific interactions independent of local environmental conditions. Second‐order feedback generally showed a large degree of variation and appears to be strongly dependent on environmental conditions and locality. There seems to be no consistent latitudinal pattern or non‐linearity in the feedback responses. We conclude that northern small rodent populations are basically regulated by both highly consistent first‐order feedback (e.g. intra‐specific competition, functional responses of generalist predators) and less consistent, site‐specific second‐order effects (e.g. numerical responses of specialist predators or food plants).
A preliminary in vitro study into the use of IL‐1Ra gene therapy for the inhibition of intervertebral disc degeneration
Authors: Le Maitre Christine L. , Freemont Anthony J. , Hoyland Judith A.
Published: January 2006

Conventional therapies for low back pain (LBP) are purely symptomatic and do not target the cause of LBP, which in approximately 40% of cases is caused by degeneration of the intervertebral disc (DIVD). Targeting therapies to inhibit the process of degeneration would be a potentially valuable treatment for LBP. There is increasing evidence for a role for IL‐1 in DIVD. A natural inhibitor of IL‐1 exists, IL‐1Ra, which would be an ideal molecular target for inhibiting IL‐1‐mediated effects involved in DIVD and LBP. In this study, the feasibility of ex vivo gene transfer of IL‐1Ra to the IVD was investigated. Monolayer and alginate cultures of normal and degenerate human intervertebral disc (IVD) cells were infected with an adenoviral vector carrying the IL‐1Ra gene (Ad‐IL‐1Ra) and protein production measured using an enzyme‐linked immunosorbent assay. The ability of these infected cells to inhibit the effects of IL‐1 was also investigated. In addition, normal and degenerate IVD cells infected with Ad‐IL‐1Ra were injected into degenerate disc tissue explants and IL‐1Ra production in these discs was assessed. This demonstrated that both nucleus pulposus and annulus fibrosus cells infected with Ad‐IL‐1Ra produced elevated levels of IL‐1Ra for prolonged time periods, and these infected cells were resistant to IL‐1. When the infected cells were injected into disc explants, IL‐1Ra protein expression was increased which was maintained for 2 weeks of investigation. This in vitro study has shown that the use of ex vivo gene transfer to degenerate disc tissue is a feasible therapy for the inhibition of IL‐1‐mediated events during disc degeneration.
A vitellogenic‐like carboxypeptidase expressed by human macrophages is localized in endoplasmic reticulum and membrane ruffles
Authors: Harris James , Schwinn Nicole , Mahoney James A. , Lin Hsi‐Hsien , Shaw Michael , Howard Chris J. , Da Silva Rosangela P. , Gordon Siamon
Published: January 2006

Carboxypeptidase, vitellogenic‐like (CPVL) is a serine carboxypeptidase of unknown function that was first characterized in human macrophages. Initial studies suggested that CPVL is largely restricted to the monocytic lineage, although it may also be expressed by cells outside the immune system. Here, we use a new monoclonal antibody to characterize the properties and localization of CPVL in human macrophages to elucidate a possible function for the protease. CPVL is up‐regulated during the maturation of monocytes (MO) to macrophages, although the protein can be seen in both. In primary macrophages, CPVL is glycosylated with high mannose residues and colocalizes with markers for endoplasmic reticulum, while in MO it is more disperse and less clearly associated with endoplasmic reticulum. CPVL is highly expressed in lamellipodia and membrane ruffles, which also concentrate markers of the secretory pathway (MIP‐1α and tumour necrosis factor‐α) and major histocompatibility complex (MHC) class I and II molecules. CPVL can be seen on early latex bead and Candida albicans phagosomes, but it is not retained in the maturing phagosome, unlike MHC class I/II. CPVL has a mixed cytosolic and membrane‐associated localization but is not detectable on the outer plasma membrane. We propose that CPVL may be involved in antigen processing, the secretory pathway and/or in actin remodelling and lamellipodium formation.
Early and late immunohistochemical and ultrastructural changes associated with functional impairment of the lachrymal gland following external beam radiation
Authors: Hakim Samer G. , Schroder Christina , Geerling Gerd , Lauer Isabel , Wedel Thilo , Kosmehl Hartwig , Driemel Oliver , Jacobsen Hans‐Christian , Trenkle Thomas , Hermes Dirk , Sieg Peter
Published: January 2006

The aim of this study was to investigate scintigraphic, immunohistological and ultrastructural changes associated with radiation‐induced dysfunction of the lachrymal gland in an established experimental animal model. Ten rabbits were randomized into two groups and used for the study; in the control as well as experimental group, the Schirmer‐test, lachrymal gland scintigraphy, and immunohistological and ultrastructural investigations were carried out prior to irradiation and 72 h as well as 1 month after single‐dose irradiation with 15 Gy. Seventy‐two hours after irradiation, secretion reduction evaluated by the Schirmer‐test was evident. At this phase, we could observe a decrease in the expression of α‐SMA and a re‐distribution of tenascin‐C matrix. Ultrastructural changes of acinar and myoepithelial cells were noticed; simultaneously, disturbance in the primary 99mTcO4– uptake as well as significant reduction of the lachrymal ejection fraction was assessed scintigraphically. These changes were still evident 1 month following irradiation but became less intensive. Single‐dose irradiation with 15 Gy implicates a functional impairment of the lachrymal gland, which is associated with early immunohistological and ultrastructural alterations. These changes may represent objective surrogate parameters for radiogenic dysfunction and prerequisites for further investigations on radioprotection of lachrymal glands during radiotherapy of the periorbital region.
Immunohistochemical and genetic features of gastric and metastatic liver gastrointestinal stromal tumors: Sequential analyses
Authors: Kikuchi Hirotoshi , Yamashita Kimihiro , Kawabata Toshiki , Yamamoto Masayoshi , Hiramatsu Yoshihiro , Kondo Kenji , Baba Megumi , Ohta Manabu , Kamiya Kinji , Tanaka Tatsuo , Suzuki Shohachi , Kitagawa Kyoko , Kitagawa Masatoshi , Sugimura Haruhiko , Konno Hiroyuki
Published: January 2006

Metastatic gastrointestinal stromal tumors (GIST) have an extremely poor prognosis; however, their immunohistochemical and genetic features have not been assessed satisfactorily and the mechanisms responsible for their high malignant potential remain unclear. We examined the immunohistochemical differences between gastric GIST and metastatic lesions in the liver of four patients who had undergone a postgastrectomy hepatectomy for metachronous liver metastases. We also carried out genetic analysis of the tumors in three of the four cases. In all cases, the immunoreactivity profiles, including KIT (CD117), CD34, smooth muscle actin (SMA), desmin, S‐100 and vimentin, were similar between the gastric and metastatic tumors, but the Ki67 labeling index in the metastatic GIST was higher than that of the primary GIST. Interestingly, in the case who had received neoadjuvant imatinib therapy before gastrectomy, its therapeutic effect was observed in most of the primary lesion, with the exception of a specific small area with high cellularity. Genetic analysis revealed no acquired mutations in the c‐kit or PDGFRA genes in the metastatic lesions in any of the patients, but loss of heterozygosity (LOH) of the c‐kit gene was observed mainly in the metastatic tumors in two of the three cases. Furthermore, in the case of neoadjuvant imatinib therapy, LOH of the c‐kit gene was shown in the high cellularity area in the primary lesion and metastatic liver GIST. It is suggested that LOH of the c‐kit gene is an important event that leads to imatinib resistance and metastatic progression of GIST. In conclusion, both gastric and metastatic GIST had almost the same immunohistochemical features, except for their proliferative activity, and LOH of the c‐kit gene played an important role in the process of liver metastasis. (Cancer Sci 2006; 97: 127 – 132)