bluuebunny/crossref_metadata_2025 huggingface dataset:
Skin friction blistering: computer model
Authors: Xing Malcolm , Pan Ning , Zhong Wen , Maibach Howard
Published: February 2007

Background/purpose: Friction blisters, a common injury in sports and military operations, can adversely effect or even halt performance. Given its frequency and hazardous nature, recent research efforts appear limited. Blistering can be treated as a delamination phenomenon; similar issues in materials science have been extensively investigated in theory and experiment. An obstacle in studying blistering is the difficulty of conducting experiment on humans and animals. Computer modeling thus becomes a preferred tool.

Method: This paper used a dynamic non‐linear finite‐element model with a blister‐characterized structure and contact algorithm for outer materials and blister roof to investigate the effects on deformation and stress of an existing blister by changing the friction coefficient and elastic modulus of the material in contact with the blister.

Results: Through the dynamics mode and harmonic frequency approach, we demonstrated that the loading frequency leads to dramatic changes of displacement and stress in spite of otherwise similar loading. Our simulations show that an increased friction coefficient does not necessarily result in an increase in either the stress on the hot spot or blister deformation; local maximum friction stress and Von Mises stress exist for some friction coefficients over the wide range examined here. In addition, the stiffness of contact material on blistering is also investigated, and no significant effects on deformation and Von Mises stress are found, again at the range used. The model and method provided here may be useful for evaluating loading environments and contact materials in reducing blistering incidents.

Conclusion: The coupling finite‐element model can predict the effects of friction coefficient and contacting materials&apos stiffness on blister deformation and hot spot stress.
Selection for contextual fear conditioning affects anxiety‐like behaviors and gene expression
Authors: Ponder C. A. , Kliethermes C. L. , Drew M. R. , Muller J. , Das K. , Risbrough V. B. , Crabbe J. C. , Gilliam T. Conrad , Palmer A. A.
Published: February 2007

Conditioned fear and anxiety‐like behaviors have many similarities at the neuroanatomical and pharmacological levels, but their genetic relationship is less well defined. We used short‐term selection for contextual fear conditioning (FC) to produce outbred mouse lines with robust genetic differences in FC. The high and low selected lines showed differences in fear learning that were stable across various training parameters and were not secondary to differences in sensitivity to the unconditioned stimulus (foot shock). They also showed a divergence in fear potentiated startle, indicating that differences induced by selection generalized to another measure of fear learning. However, there were no differences in performance in a Pavlovian approach conditioning task or the Morris water maze, indicating no change in general learning ability. The high fear learning line showed greater anxiety‐like behavior in the open field and zero maze, confirming a genetic relationship between FC and anxiety‐like behavior. Gene expression analysis of the amygdala and hippocampus identified genes that were differentially expressed between the two lines. Quantitative trait locus (QTL) analysis identified several chromosomal regions that may underlie the behavioral response to selection; cis‐acting expression QTL were identified in some of these regions, possibly identifying genes that underlie these behavioral QTL. These studies support the validity of a broad genetic construct that includes both learned fear and anxiety and provides a basis for further studies aimed at gene identification.
A Study on Variances in Multivariate Analyses of Oral Implant Outcome
Authors: Herrmann Irene , Kultje Christina , Holm Sture , Lekholm Ulf
Published: February 2007

Background:  Elaborate studies have shown that interdependency exists between implants being placed in the same patient/jaw. Therefore, interdependency ought to be an important aspect to address, whenever performing statistical analyses of oral implant outcomes. A Jackknife method could be an option when conducting statistical evaluations of oral implant failure prognoses.

Purpose:  The aim of this study was to evaluate whether a statistical difference can be detected by using the Jackknife method in conjunction with life table analyses and/or a log rank test of four different combinations of jaw density and quantity.

Materials and Methods:  Four multicenter studies were pooled and adjusted in order to create a research database consisting of 486 patients and 1,737 implants in preparation for the Jackknife resampling method. Combinations of jaw shapes and bone qualities were constructed to select at‐risk patients.

Statistical Methods:  Life tables with confidence intervals were calculated and a log rank test was used to determine whether a statistical difference between the combinations could be established.

Results:  Both statistical analyses, after the Jackknife resampling method, showed that patients with poor bone quality and resorbed jaws (combination IV) had a statistically higher risk of implant failure.

Conclusion:  By rearranging data using the Jackknife method, standardized statistical tests seem to work well even when the study population tested was affected by interdependency.
Immediately Restored, Single‐Tapered Implants in the Anterior Maxilla: Prosthodontic and Aesthetic Outcomes After 1 Year
Authors: Hall James A. G. , Payne Alan G. T. , Purton David G. , Torr Brendan , Duncan Warwick J. , De Silva Rohana Kumara
Published: February 2007

Background:  Conventional implant protocols advocate a two‐stage technique with a load‐free, submerged healing period. Recent studies suggest that immediate restoration of single implants may be a viable treatment option.

Purpose:  The purpose of this study was to evaluate prosthodontic and aesthetic peri‐implant mucosal outcomes of immediately restored, Southern single‐tapered implants in the anterior maxilla after 1 year.

Materials and Methods:  Participants (mean age: 43.25 years; range: 23–71 years) satisfying specified inclusion criteria were randomly allocated to conventional two‐stage restoration (control group; n=14) and immediate restoration groups (test group; n =14) in a randomized controlled clinical trial. Tapered, roughened‐surface Southern implants were placed using a standardized technique, and implant level bone impressions were made. Provisional screw‐retained crowns, out of occlusion, were placed at second‐stage surgery after 26 weeks for the conventional restoration group, and within 4 hours of implant placement for the immediate restoration group. Both groups had definitive screw‐retained metal‐ceramic crowns placed in occlusion 8 weeks later. Peri‐implant mucosal response and papilla index were recorded 4 weeks after definitive crown placement to allow for mucosal maturation and at 1 year. Prosthodontic and aesthetic outcomes were assessed using established criteria.

Results:  There were no significant differences within, or between, the control and test groups for age, gender, bone quality or quantity, implant stability measurements at surgery, or implant length. There were no significant differences in the implant success rate as determined by radiographic bone loss and stability tests after 1 year. There were no significant differences in prosthodontic maintenance, peri‐implant mucosal response, and papilla index between the two groups over 1 year.

Conclusions:  Tapered, roughened‐surface implants immediately restored with single provisional crowns at surgery and definitive crowns 8 weeks later were as prosthodontically and aesthetically successful as conventionally restored two‐stage implants during the first year of service. Restoring single implants immediately with screw‐retained crowns is an efficient procedure, but the short‐term outcome is by no means superior to a conventional two‐stage approach.
Influence of Transducer Orientation on OsstellTM Stability Measurements of Osseointegrated Implants
Authors: Veltri Mario , Balleri Piero , Ferrari Marco
Published: February 2007

Background:  Resonance frequency (RF) analysis is frequently used to monitor implant stability in patients. The influence of transducer orientation on RF of implants placed in jawbone has not been evaluated.

Purpose:  The aim of this study was to evaluate to what extent transducer orientation influences RF. The second aim was to evaluate if measurements taken with any particular orientation would best relate to marginal bone levels.

Materials and Methods:  Nine patients edentulous in the upper jaw received 55 implants 3 years before this study. They underwent clinical and radiographic evaluation. Using OsstellTM (Integration Diagnostics AB, Göteborg, Sweden), four RF measurements were made for each implant. Measurements were obtained with the transducer cantilever placed buccally (B), distally (D), palatally (P), and mesially (M).

Results:  All implants were clinically stable. Significant differences resulted between the measurements perpendicular to the bony crest (B, P) and the parallel ones (M, D). A tendency of negative correlation was found between marginal bone levels and implant stability quotient (ISQ) measurements; however, this correlation was not statistically significant.

Conclusions:  In conclusion, when measuring the RF of dental implants using the Osstell, it has to be taken into account that the transducer orientation influences the measurement. It seems therefore advisable to standardize the orientation. Moreover, although there was a tendency, any statistical significant correlation between ISQ values and marginal bone levels could not be established.
Cloning and sequencing of ovine Flt3 ligand
Authors: Chan S. S. M. , Lyons N. , McConnell I. , Blacklaws B. A.
Published: February 2007

A cDNA (879 bp) containing the complete open reading frame of ovine Fms‐related tyrosine kinase 3 ligand (Flt3‐L) was amplified by reverse transcriptase polymerase chain reaction (RT‐PCR), cloned and sequenced. The deduced amino acid sequence has 97.6% similarity with bovine Flt3‐L isoform 1 and shares the long cytoplasmic domain observed in bovine Flt3‐L but not in human Flt3‐L.
The Effect of Patient Age and Other Factors on the Maintenance of Permanent Hemodialysis Vascular Access
Authors: Hayakawa Kunihiro , Miyakawa Shinzaburo , Hoshinaga Kiyotaka , Hata Kenichi , Marumo Ken , Hata Makoto
Published: February 2007

Abstract:  The objective of the present study was to investigate whether patient age is associated with vascular access failure during maintenance hemodialysis. Thus, patients who had a successful permanent hemodialysis vascular access installed (Group N: 314 cases), and those who required vascular access revision (Group R: 108 patients) were studied. To assess the association between patient age and the risk of vascular access failure, Cox proportional hazards regression was used to determine hazard ratios (HR) and 95% confidence intervals (CI). We found that in Group N, the significant risk factors were age, gender, and diabetes mellitus (95% CI: 1.004–1.013, 0.380–0.827, 1.279–2.859). Using a univariate analysis model, significant hazard ratios (HR) were found with ages of 60 (CI: 1.062–2.302), 65 (CI: 1.052–2.280), and 70 (CI: 1.082–2.537) years, with the largest HR at 70 years of age (HR: 1.657). In contrast, in Group R, multivariate analysis using Cox proportional hazards identified only one prognostic variable, the location of the vascular access. In Group R, univariate analysis models showed that age was not a significant factor. We conclude that our data show that age is a risk factor for the successful maintenance of initial permanent hemodialysis vascular access. Other risk factors include gender and diabetes mellitus. However, these factors were not related to the successful maintenance of revised vascular access.
THE TEACHING OF FOOD RHEOLOGY
Authors: MULLER H. G. , WARD A. G.
Published: February 2007

A brief account of the rheology course for undergraduates at the Procter Department of Food and Leather Science of Leeds University is given. Both the practical and theoretical approaches are considered. The former deals with present methods of rheological assessment, the latter should provide a sound foundation for future rheological research.
THE TEXTURE TESTER, PRINCIPLES AND SELECTED APPLICATIONS*
Authors: SZCZESNIAK ALINA S. , EINSTEIN MAJORIE , E RICHARD E. PABST R.
Published: February 2007

An automatic, self‐cleaning, recording instrument for testing textural properties of bite‐size food pieces is described. The unit can be fitted with several types of test cells; results obtained with the shear cell are reported. Forces to break, compress, shear and push the food through the blades were identified from the recorded force‐displacement curves. Typical curves for a variety of foods are given and applications of the unit to testing cold cereals, peas, fruit pieces etc. are described. The instrument lends itself well to generating data for construction of force distribution patterns which may describe geometrically small foods better than the average force reading.
Angiostrongylus vasorum (French heartworm) in a dog imported into Australia
Authors: Tebb AI , Johnson VS , Irwin PJ
Published: February 2007

This report describes a case of Angiostonglyus vasorum infection, sometimes referred to as French heartworm disease, in a dog imported into Western Australia from the United Kingdom. Diagnosis was made by identification of first stage larvae on fine needle aspiration of a consolidated lung lobe. First stage larvae were also identified in the faeces by the Baermann technique. The main clinical signs in this case were coughing and tachypnoea. The dog was treated successfully with fenbendazole at 50 mg/kg once daily for 10 days.
Assortative mating and patterns of inheritance indicate that the three crossbill taxa in Scotland are species
Authors: Summers Ron W. , Dawson Robert J. G. , Phillips Ron E.
Published: February 2007

There are three breeding taxa of crossbills in highland Scotland, the common crossbill Loxia curvirostra, parrot crossbill L. pytyopsittacus and endemic Scottish crossbill L. scotica. These taxa show no genetic differentiation in neutral DNA (microsatellites and mitochondrial DNA), but do show some differentiation in morphology and have distinct calls. Mating patterns and bill size inheritance were examined to test four different hypotheses for their genetic similarity: (1) the three taxa belong to the same species and differences in bill sizes are caused by phenotypic plasticity, (2) the taxa are a result of genetic polymorphism at a single locus, (3) the taxa largely act as species but occasionally cross‐breed, such that gene flow results in genetic homogenisation of part of the genome, and (4) the taxa are fully reproductively isolated species but diverged only recently, such that insufficient time has passed for neutral DNA to differentiate by genetic drift. Hypotheses 1 and 2 could be excluded because wild crossbills mated assortatively with respect to bill depth (a measure of bill size) and bill depth was highly heritable; narrow‐sense heritabilities of 0.58 for female and 0.71 for male Scottish crossbills. Only two of 46 pairs (4.3%) were not assortative by bill size. Pairing was strongly assortative by flight calls (50 out of 52 pairs, 96.2%) and excitement calls (88 out of 93 pairs, 94.6%). Therefore, the three crossbill taxa do not cross‐mate freely, nor do they seem totally reproductively isolated (excluding hypothesis 4). Thus, the results mostly favour hypothesis 3. The small amount of gene flow among crossbill taxa may contribute to the lack of genetic differentiation in neutral DNA. However, this appears to be insufficient not to classify them as species, as long as the calls can be regarded as diagnostic.
Regional sympathetic denervation affects the relation between canine local myocardial blood flow and oxygen consumption
Authors: Alders David J. C. , Cornelussen Richard N. , Prinzen Frits W. , Specht Patricia A. C. , Noble Mark I. M. , Drake‐Holland Angela J. , De Kanter Frans J. J. , Van Beek Johannes H. G. M.
Published: February 2007

Myocardial blood flow and oxygen consumption are heterogeneously distributed. Perfusion and myocardial oxygen consumption are closely correlated in the normal heart. It is unknown how this metabolism–perfusion relation is influenced by sympathetic denervation. We investigated this question in seven chloralose‐anaesthetized dogs, 3–4 weeks after regional sympathetic denervation of the left circumflex coronary artery area of supply of the left ventricle. Measurements were made of local myocardial blood flow (MBF, in ml min−1 (g dry wt)−1), measured with microspheres, and myocardial oxygen consumption (
, in μmol min−1 (g dry wt)−1) in the same location, calculated from the 13C spectrum of tissue extracts after intracoronary infusion of 3–13C‐lactate. Since both innervated and denervated regions are subject to the same arterial pressure, lower blood flow indicates higher resistance. Mean MBF was 5.56 ml min−1 (g dry wt)−1 (heterogeneity of 3.47 ml min−1 (g dry wt)−1) innervated, 7.48 ml min−1 (g dry wt)−1 (heterogeneity of 3.62 ml min−1 (g dry wt)−1) denervated (n.s.). Significant linear relations were found between MBF and
of individual samples within the innervated and denervated regions. The slopes of these relations were not significantly different, but the adjusted mean was significantly higher in the denervated regions (+1.92 ml min−1 (g dry wt)−1, an increase of 38% of the mean MBF at the pooled mean
, P= 0.028, ANCOVA). The ratio
(in ml μmol−1) was significantly higher, being 0.296 ± 0.167 ml μmol−1 in the denervated region compared with the innervated region, 0.216 ± 0.126 ml μmol−1, P= 0.0182, Mann–Whitney U test. These results indicate that sympathetic tone under chloralose anaesthesia imposes a moderate vasoconstrictive effect in the myocardium that is not detected by comparison of the mean blood flow or resistance.
Brain superoxide as a key regulator of the cardiovascular response to emotional stress in rabbits
Authors: Mayorov Dmitry N.
Published: February 2007

Cardiovascular reactivity, an abrupt increase in blood pressure and heart rate in response to emotional stress, is a risk factor for hypertension and heart disease. Brain angiotensin II (Ang II) type 1 (AT1) receptor is increasingly recognized as an important regulator of cardiovascular reactivity. Given that a wide variety of AT1 receptor signalling pathways exists in neurones, the precise molecular mechanisms that underlie central cardiovascular actions of Ang II during emotional stress are yet to be determined. Growing evidence, however, indicates that reactive oxygen species, and in particular superoxide (·O2−), are important intracellular messengers of many actions of brain Ang II. In particular, studies employing microinjection of ·O2− scavengers directly into the rostral ventrolateral medulla (RVLM) and dorsomedial hypothalamus of rabbits have shown that the activation of AT1 receptor–·O2− signalling is required for full manifestation of the cardiovascular response to emotional stress. This role of ·O2− appears to be highly specific, because ·O2− scavengers in the RVLM do not alter the sympathoexcitatory response to baroreceptor unloading or sciatic nerve stimulation. The subcellular mechanisms for the stress‐induced ·O2− production are likely to include the activation of NADPH oxidase and are essentially independent of nitric oxide. This review summarizes current knowledge of redox‐sensitive signalling mechanisms in the brain that regulate cardiovascular effects of stress. Additionally, it presents initial evidence that ·O2− may be less important in the activation of central pressor pathways mediating cardiovascular arousal associated with appetitive events, such as food anticipation and feeding.
The effects of inhibitory and facilitatory intracortical circuits on interhemispheric inhibition in the human motor cortex
Authors: Lee Hubert , Gunraj Carolyn , Chen Robert
Published: February 2007

Inhibitory and facilitatory intracortical pathways regulating motor cortical output can be studied non‐invasively in humans with transcranial magnetic stimulation. These circuits include short‐interval intracortical inhibition (SICI), long‐interval intracortical inhibition (LICI) and intracortical facilitation (ICF). Stimulation of the motor cortex also inhibits the contralateral motor cortex (interhemispheric inhibition, IHI) at short (∼10 ms, IHI10) or long intervals (∼40 ms, IHI40). We investigated how SICI, ICF, and LICI influence IHI10 and IHI40. We hypothesize that intracortical circuits will have similar effects on IHI and cortical output neurons: SICI and LICI will decrease IHI, and ICF will increase it. Motor evoked potentials were recorded from the first dorsal interosseous muscles bilaterally in 10 healthy subjects. We compared IHI10 and IHI40 alone to IHI10 and IHI40 elicited in the presence of SICI, ICF, or LICI. Our results showed that SICI and LICI reduced IHI10, IHI40 and corticospinal output to a similar degree. ICF increased corticospinal output but had no effect on either IHI10 or IHI40. The different effects of ICF on corticospinal excitability and IHI suggest the transcallosal fibres mediating IHI and the corticospinal output system arise from different neuronal populations. SICI and LICI produce more global inhibition with similar effects on the transcallosal and descending corticospinal circuits.
BK potassium channels facilitate high‐frequency firing and cause early spike frequency adaptation in rat CA1 hippocampal pyramidal cells
Authors: Gu Ning , Vervaeke Koen , Storm Johan F.
Published: February 2007

Neuronal potassium (K+) channels are usually regarded as largely inhibitory, i.e. reducing excitability. Here we show that BK‐type calcium‐activated K+ channels enhance high‐frequency firing and cause early spike frequency adaptation in neurons. By combining slice electrophysiology and computational modelling, we investigated functions of BK channels in regulation of high‐frequency firing in rat CA1 pyramidal cells. Blockade of BK channels by iberiotoxin (IbTX) selectively reduced the initial discharge frequency in response to strong depolarizing current injections, thus reducing the early spike frequency adaptation. IbTX also blocked the fast afterhyperpolarization (fAHP), slowed spike rise and decay, and elevated the spike threshold. Simulations with a computational model of a CA1 pyramidal cell confirmed that the BK channel‐mediated rapid spike repolarization and fAHP limits activation of slower K+ channels (in particular the delayed rectifier potassium current (IDR)) and Na+ channel inactivation, whereas M‐, sAHP‐ or SK‐channels seem not to be important for the early facilitating effect. Since the BK current rapidly inactivates, its facilitating effect diminishes during the initial discharge, thus producing early spike frequency adaptation by an unconventional mechanism. This mechanism is highly frequency dependent. Thus, IbTX had virtually no effect at spike frequencies < 40 Hz. Furthermore, extracellular field recordings demonstrated (and model simulations supported) that BK channels contribute importantly to high‐frequency burst firing in response to excitatory synaptic input to distal dendrites. These results strongly support the idea that BK channels play an important role for early high‐frequency, rapidly adapting firing in hippocampal pyramidal neurons, thus promoting the type of bursting that is characteristic of these cells in vivo, during behaviour.
Pattern Separation in the Dentate Gyrus and CA3 of the Hippocampus
Authors: Leutgeb Jill K. , Leutgeb Stefan , Moser May-Britt , Moser Edvard I.
Published: February 2007

Theoretical models have long pointed to the dentate gyrus as a possible source of neuronal pattern separation. In agreement with predictions from these models, we show that minimal changes in the shape of the environment in which rats are exploring can substantially alter correlated activity patterns among place-modulated granule cells in the dentate gyrus. When the environments are made more different, new cell populations are recruited in CA3 but not in the dentate gyrus. These results imply a dual mechanism for pattern separation in which signals from the entorhinal cortex can be decorrelated both by changes in coincidence patterns in the dentate gyrus and by recruitment of nonoverlapping cell assemblies in CA3.
Predation Risk Affects Reproductive Physiology and Demography of Elk
Authors: Creel Scott , Christianson David , Liley Stewart , Winnie John A.
Published: February 2007

Elk (Cervus elaphus) in the Greater Yellowstone Ecosystem alter patterns of aggregation, habitat selection, vigilance, and foraging in the presence of wolves (Canis lupus). Antipredator behaviors like these can reduce predation risk but are also likely to carry costs. Data from five elk populations studied for 16 site years showed that progesterone concentrations (from 1489 fecal samples) declined with the ratio of elk to wolves. In turn, progesterone concentrations were a good predictor of calf recruitment in the subsequent year. Together, these data suggest that wolves indirectly affect the reproductive physiology and the demography of elk through the costs of antipredator behavior.
Multipotent
Drosophila
Intestinal Stem Cells Specify Daughter Cell Fates by Differential Notch Signaling
Authors: Ohlstein Benjamin , Spradling Allan
Published: February 2007

The adult
Drosophila
midgut contains multipotent intestinal stem cells (ISCs) scattered along its basement membrane that have been shown by lineage analysis to generate both enterocytes and enteroendocrine cells. ISCs containing high levels of cytoplasmic Delta-rich vesicles activate the canonical Notch pathway and down-regulate Delta within their daughters, a process that programs these daughters to become enterocytes. ISCs that express little vesiculate Delta, or are genetically impaired in Notch signaling, specify their daughters to become enteroendocrine cells. Thus, ISCs control daughter cell fate by modulating Notch signaling over time. Our studies suggest that ISCs actively coordinate cell production with local tissue requirements by this mechanism.
Starch Fossils and the Domestication and Dispersal of Chili Peppers (
Capsicum
spp. L.) in the Americas
Authors: Perry Linda , Dickau Ruth , Zarrillo Sonia , Holst Irene , Pearsall Deborah M. , Piperno Dolores R. , Berman Mary Jane , Cooke Richard G. , Rademaker Kurt , Ranere Anthony J. , Raymond J. Scott , Sandweiss Daniel H. , Scaramelli Franz , Tarble Kay , Zeidler James A.
Published: February 2007

Chili peppers (
Capsicum
spp.) are widely cultivated food plants that arose in the Americas and are now incorporated into cuisines worldwide. Here, we report a genus-specific starch morphotype that provides a means to identify chili peppers from archaeological contexts and trace both their domestication and dispersal. These starch microfossils have been found at seven sites dating from 6000 years before present to European contact and ranging from the Bahamas to southern Peru. The starch grain assemblages demonstrate that maize and chilies occurred together as an ancient and widespread Neotropical plant food complex that predates pottery in some regions.
Molecular Epidemiology of Astrovirus Infection in Infants in Wuhan, China
Authors: Liu Man-Qing , Yang Bei-Fang , Peng Jin-Song , Zhou Dun-Jin , Tang Li , Wang Bin , Liu Yu , Sun Shi-Hong , Ho Wen-Zhe
Published: February 2007

We report the molecular epidemiology of astrovirus infection in 335 infants with diarrhea in Wuhan City, China. Astrovirus RNA was detected in the stool specimens of 33 children (9.87%). Genotyping analysis indicated that 23 out of 24 astroviruses identified were classified as belonging to genotype 1, with highest identity (>98%) to a Mongolian strain.
Worldwide Occurrence of Feline Hemoplasma Infections in Wild Felid Species
Authors: Willi Barbara , Filoni Claudia , Catão-Dias José L. , Cattori Valentino , Meli Marina L. , Vargas Astrid , Martínez Fernando , Roelke Melody E. , Ryser-Degiorgis Marie-Pierre , Leutenegger Christian M. , Lutz Hans , Hofmann-Lehmann Regina
Published: February 2007

While hemoplasma infections in domestic cats are well studied, almost no information is available on their occurrence in wild felids. The aims of the present study were to investigate wild felid species as possible reservoirs of feline hemoplasmas and the molecular characterization of the hemoplasma isolates. Blood samples from the following 257 wild felids were analyzed: 35 Iberian lynxes from Spain, 36 Eurasian lynxes from Switzerland, 31 European wildcats from France, 45 lions from Tanzania, and 110 Brazilian wild felids, including 12 wild felid species kept in zoos and one free-ranging ocelot. Using real-time PCR, feline hemoplasmas were detected in samples of the following species: Iberian lynx, Eurasian lynx, European wildcat, lion, puma, oncilla, Geoffroy's cat, margay, and ocelot. “CandidatusMycoplasma haemominutum” was the most common feline hemoplasma in Iberian lynxes, Eurasian lynxes, Serengeti lions, and Brazilian wild felids, whereas “CandidatusMycoplasma turicensis” was the most prevalent in European wildcats; hemoplasma coinfections were frequently observed. Hemoplasma infection was associated with species and free-ranging status of the felids in all animals and with feline leukemia virus provirus-positive status in European wildcats. Phylogenetic analyses of the 16S rRNA and the partial RNase P gene revealed that most hemoplasma isolates exhibit high sequence identities to domestic cat-derived isolates, although some isolates form different subclusters within the phylogenetic tree. In conclusion, 9 out of 15 wild felid species from three different continents were found to be infected with feline hemoplasmas. The effect of feline hemoplasma infections on wild felid populations needs to be further investigated.
Distribution Study ofChlamydia trachomatisSerovars among High-Risk Women in China Performed Using PCR-Restriction Fragment Length Polymorphism Genotyping
Authors: Gao Xing , Chen Xiang-Sheng , Yin Yue-Ping , Zhong Ming-Ying , Shi Mei-Qin , Wei Wan-Hui , Chen Qiang , Peeling Rosanna W. , Mabey David
Published: February 2007

This was one of the first epidemiological studies in China focused on genitalChlamydia trachomatisserotype distribution in high-risk female populations usingomp1gene-based restriction fragment length polymorphism analysis. One thousand seven hundred seventy cervical swab samples from women attending sexually transmitted disease clinics and female sex workers in six cities in China (Shenzhen and Guangzhou in southern China, Nanjing and Shanghai in eastern China, and Nanning and Chengdu in southwestern China) were subjected to serovar genotyping. The proportion ofomp1genes successfully amplified in 240C. trachomatisplasmid-positive samples was 94.2% (226/240). Serotypes E (n= 63; 27.9%), F (n= 53; 23.5%), G (n= 28; 12.4%), and D (n= 25; 11.1%) were most prevalent. Though there was no significant difference in the geographic distribution ofC. trachomatis, serotype E was predominant in the South (32.1%) and East (27.1%), while serotype F was predominant in the Southwest (28.3%). Serotype F infection was associated with young age and single status. Serovar G was associated with lower abdominal pain; 47.5% of asymptomatic patients were infected with serovar E. These results provide information on distribution of genitalC. trachomatisserotypes among high-risk women in China and indicate that high-risk women, including those who are asymptomatic, can be infected with multiple serovars ofC. trachomatis, revealing exposure to multiple sources of infection. Although the scope for generalizations is limited by our small sample size, our results showing clinical correlations with genotypes are informative.
Analysis of Hepatitis C Virus Superinfection Exclusion by Using Novel Fluorochrome Gene-Tagged Viral Genomes
Authors: Schaller Torsten , Appel Nicole , Koutsoudakis George , Kallis Stephanie , Lohmann Volker , Pietschmann Thomas , Bartenschlager Ralf
Published: February 2007

Studies of the complete hepatitis C virus (HCV) life cycle have become possible with the development of an infectious cell culture system using the genotype 2a isolate JFH-1. Taking advantage of this system in the present study, we investigated whether HCV infection leads to superinfection exclusion, a state in which HCV-infected cells are resistant to secondary HCV infection. To discriminate between viral genomes, we inserted genes encoding fluorescent proteins in frame into the 3′-terminal NS5A coding region. These genomes replicated to wild-type levels and supported the production of infectious virus particles. Upon simultaneous infection of Huh-7 cells, coreplication of both viral genomes in the same cell was detected. However, when infections were performed sequentially, secondary infection was severely impaired. This superinfection exclusion was neither due to a reduction of cell surface expression of CD81 and scavenger receptor BI, two molecules implicated in HCV entry, nor due to a functional block at the level of virus entry. Instead, superinfection exclusion was mediated primarily by interference at the level of HCV RNA translation and, presumably, also replication. In summary, our results describe the construction and characterization of viable monocistronic HCV reporter genomes allowing detection of viral replication in infected living cells. By using these genomes, we found that HCV induces superinfection exclusion, which is primarily due to interference at a postentry step.
Polybasic KKR Motif in the Cytoplasmic Tail of Nipah Virus Fusion Protein Modulates Membrane Fusion by Inside-Out Signaling
Authors: Aguilar Hector C. , Matreyek Kenneth A. , Choi Daniel Y. , Filone Claire Marie , Young Sophia , Lee Benhur
Published: February 2007

The cytoplasmic tails of the envelope proteins from multiple viruses are known to contain determinants that affect their fusogenic capacities. Here we report that specific residues in the cytoplasmic tail of the Nipah virus fusion protein (NiV-F) modulate its fusogenic activity. Truncation of the cytoplasmic tail of NiV-F greatly inhibited cell-cell fusion. Deletion and alanine scan analysis identified a tribasic KKR motif in the membrane-adjacent region as important for modulating cell-cell fusion. The K1A mutation increased fusion 5.5-fold, while the K2A and R3A mutations decreased fusion 3- to 5-fold. These results were corroborated in a reverse-pseudotyped viral entry assay, where receptor-pseudotyped reporter virus was used to infect cells expressing wild-type or mutant NiV envelope glycoproteins. Differential monoclonal antibody binding data indicated that hyper- or hypofusogenic mutations in the KKR motif affected the ectodomain conformation of NiV-F, which in turn resulted in faster or slower six-helix bundle formation, respectively. However, we also present evidence that the hypofusogenic phenotypes of the K2A and R3A mutants were effected via distinct mechanisms. Interestingly, the K2A mutant was also markedly excluded from lipid rafts, where ∼20% of wild-type F and the other mutants can be found. Finally, we found a strong negative correlation between the relative fusogenic capacities of these cytoplasmic-tail mutants and the avidities of NiV-F and NiV-G interactions (P= 0.007,r2= 0.82). In toto, our data suggest that inside-out signaling by specific residues in the cytoplasmic tail of NiV-F can modulate its fusogenicity by multiple distinct mechanisms.
Nodavirus RNA Replication Protein A Induces Membrane Association of Genomic RNA
Authors: Van Wynsberghe Priscilla M. , Chen Hau-Ren , Ahlquist Paul
Published: February 2007

Positive-strand RNA virus genome replication occurs in membrane-associated RNA replication complexes, whose assembly remains poorly understood. Here we show that prior to RNA replication, the multifunctional, transmembrane RNA replication protein A of the nodavirus flock house virus (FHV) recruits FHV genomic RNA1 to a membrane-associated state in both
Drosophila melanogaster
and
Saccharomyces cerevisiae
cells. Protein A has mitochondrial membrane-targeting, self-interaction, RNA-dependent RNA polymerase (RdRp), and RNA capping domains. In the absence of RdRp activity due to an active site mutation (A
D692E
), protein A stimulated RNA1 accumulation by increasing RNA1 stability. Protein A
D692E
stimulated RNA1 accumulation in wild-type cells and in
xrn1
−
yeast defective in decapped RNA decay, showing that increased RNA1 stability was not due to protein A-mediated RNA1 recapping. Increased RNA1 stability was closely linked with protein A-induced membrane association of the stabilized RNA and was highly selective for RNA1. Substantial N- and C-proximal regions of protein A were dispensable for these activities. However, increased RNA1 accumulation was eliminated by deleting protein A amino acids (aa) 1 to 370 but was restored completely by adding back the transmembrane domain (aa 1 to 35) and partially by adding back peripheral membrane association sequences in aa 36 to 370. Moreover, although RNA polymerase activity was not required, even small deletions in or around the RdRp domain abolished increased RNA1 accumulation. These and other results show that prior to negative-strand RNA synthesis, multiple domains of mitochondrially targeted protein A cooperate to selectively recruit FHV genomic RNA to membranes where RNA replication complexes form.
Epstein-Barr Virus Transcription Activator Rta Upregulates Decoy Receptor 3 Expression by Binding to Its Promoter
Authors: Ho Cheng-Hsun , Hsu Chen-Fang , Fong Pei-Fen , Tai Shyh-Kuan , Hsieh Shie-Liang , Chen Chi-Ju
Published: February 2007

Decoy receptor 3 (DcR3) is a soluble decoy receptor belonging to the tumor necrosis factor receptor superfamily that is overexpressed in various malignant tumor types. DcR3 has been implicated in tumor cell survival by inhibiting apoptosis and by interfering with immune surveillance. A previous study showed that DcR3 expression is associated with Epstein-Barr virus (EBV)-positive lymphomas but rarely with non-EBV-positive B-cell lymphomas, suggesting that the presence of EBV may affect DcR3 expression. Here, we demonstrated enhanced DcR3 expression upon EBV reactivation in P3HR1 cells and in EBV-infected 293 cells. This enhancement, however, could not be detected in 293 cells infected with EBV with BRLF1 deleted. We found that EBV transactivator, Rta, could upregulate DcR3 expression by direct binding to an Rta-responsive element (RRE) located in the DcR3 promoter region and that this RRE is important for Rta-mediated DcR3 expression. Overexpressing CREB-binding protein (CBP) further enhanced Rta-dependent DcR3 expression, suggesting Rta-dependent DcR3 transcription activity is mediated by CBP. Previously, Rta was shown to enhance phosphatidylinositol-3 kinase (PI3-K) activity. However, Rta-transduced PI 3-K activity plays a minor role in DcR3 expression. This is the first report to demonstrate that Rta upregulates a cellular gene by direct binding to an RRE.
Rotavirus NSP1 Inhibits Expression of Type I Interferon by Antagonizing the Function of Interferon Regulatory Factors IRF3, IRF5, and IRF7
Authors: Barro Mario , Patton John T.
Published: February 2007

Secretion of interferon (IFN) by virus-infected cells is essential for activating autocrine and paracrine pathways that promote cellular transition to an antiviral state. In most mammalian cells, IFN production is initiated by the activation of constitutively expressed IFN regulatory factor 3, IRF3, which in turn leads to the induction of IRF7, the “master regulator” of IFN type I synthesis (alpha/beta IFN). Previous studies established that rotavirus NSP1 antagonizes IFN signaling by inducing IRF3 degradation. In the present study, we have determined that, in comparison to wild-type rotaviruses, rotaviruses encoding defective NSP1 grow to lower titers in some cell lines and that this poor growth phenotype is due to their failure to suppress IFN expression. Furthermore, we provide evidence that rotaviruses encoding wild-type NSP1 subvert IFN signaling by inducing the degradation of not only IRF3, but also IRF7, with both events occurring through proteasome-dependent processes that proceed with similar efficiencies. The capacity of NSP1 to induce IRF7 degradation may allow rotavirus to move across the gut barrier by enabling the virus to replicate in specialized trafficking cells (dendritic cells and macrophages) that constitutively express IRF7. Along with IRF3 and IRF7, NSP1 was found to induce the degradation of IRF5, a factor that upregulates IFN expression and that is involved in triggering apoptosis during viral infection. Our analysis suggests that NSP1 mediates the degradation of IRF3, IRF5, and IRF7 by recognizing a common element of IRF proteins, thereby allowing NSP1 to act as a broad-spectrum antagonist of IRF function.
Self-reported health problems and sickness absence in different age groups predominantly engaged in physical work
Authors: Taimela Simo , Lr Esa , Malmivaara Antti , Tiekso Jaakko , Sintonen Harri , Justn Selina , Aro Timo
Published: February 2007

Objectives:

To study the associations between self-reported health problems and sickness absence from work.

Methods:

The results of a questionnaire survey were combined with archival data of sickness absence of 1341 employees 88 males; 62 blue-collar in the construction, service and maintenance work within one corporation in Finland. Sex, age and occupational grading were controlled as confounders. A zero-inflated negative binomial ZINB regression model was used in the statistical analysis of sickness absence data.

Results:

The prevalence of self-reported health problems increased with age, from 23 in 1830-year-olds to 54 in 5561-year-olds. However, in those aged 1830 years, 71 had been absent from work and in those aged 5561 years this proportion was 53. When health problems and occupational grading were accounted for in the ZINB model, age as such was not associated with the number of days on sick leave, but the young workers still had higher propensity for any sickness absence than the old. Self-rated future working ability and musculoskeletal impairment were strong determinants of sickness absence. Among those susceptible to taking sick leave, the estimated mean number of absence days increased by 14 for each rise of 1 unit of the impairment score scale 010.

Conclusions:

Young subjects had surprisingly high probability for sickness absence although they reported better health than their older colleagues. A higher total count of absence days was found among subjects reporting health problems and poorer working ability, regardless of age, sex and occupational grade. These findings have implications for both management and the healthcare system in the prevention of work disability.
Comparison of clinical and electrodiagnostic features in B12 deficiency neurological syndromes with and without antiparietal cell antibodies
Authors: Misra U K , Kalita J
Published: February 2007

Background and aims

This study was undertaken to compare the clinical and electrodiagnostic (Edx) features in autoimmune and nutritional vitamin B12 deficiency neurological syndromes.

Methods

Consecutive patients with vitamin B12 deficiency neurological syndromes were evaluated and blood counts, red blood cell indices, serum chemistry, thyroid function, HIV serology, antiparietal cell antibody (APCA), serum B12, bone marrow and spinal MRI assessed. EDx studies included nerve conduction, tibial somatosensory (SEP) and motor evoked potential (MEP) to the tibialis anterior, and visual evoked potential (VEP). The results were compared between APCA positive and negative groups.

Results

57 patients aged 17–80 years (mean 45.3) were studied; 48 were vegetarians. The presenting clinical syndromes were myeloneuropathy in 25, myelopathy in 14, myeloneuroencephalopathy in 13, myeloencephalopathy in four and behavioural abnormality only in one patient. Spinal MRI in 47 patients revealed posterior spinal cord hyperintensity in 21 and cord atrophy in six. Nerve conduction was abnormal in 15%, MEP in 56.6%, SEP in 87.3% and VEP in 63.6% of patients. At 3 months, 31 patients had complete, 11 partial and three poor recovery. APCA was positive in 49% of patients. There was no difference in clinical, MRI or Edx findings or outcome between the APCA positive and negative groups.

Conclusion

APCA was positive in 49% of patients with B12 deficiency neurological syndrome but their clinical, MRI and Edx changes were not different from the APCA negative group. Neurological manifestations may be caused by B12 deficiency itself rather than the underlying cause.
Blood pressure and ageing
Authors: Pinto Elisabete
Published: February 2007

Isolated systolic hypertension, an elevation in systolic but not diastolic pressure, is the most prevalent type of hypertension in those aged 50 or over, occurring either de novo or as a development after a long period of systolic-diastolic hypertension with or without treatment. The increase in blood pressure with age is mostly associated with structural changes in the arteries and especially with large artery stiffness. It is known from various studies that rising blood pressure is associated with increased cardiovascular risk. In the elderly, the most powerful predictor of risk is increased pulse pressure due to decreased diastolic and increased systolic blood pressure. All evidence indicates that treating the elderly hypertensive patient will reduce the risk of cardiovascular events. However, there is no evidence yet for the very elderly. This population is particularly susceptible to side effects of treatments and the reduction of blood pressure, although reducing the risk of cardiovascular events such as stroke, may result in increased mortality.
THE SPIN PUZZLE: RECENT RESULTS FROM THE HERMES EXPERIMENT
Authors:   FOR THE HERMES COLLABORATION., FANTONI ALESSANDRA
Published: February 2007

The HERMES experiment at DESY has been designed to study the spin structure of the nucleon. Impressive results have been obtained not only in inclusive processes but also for semi-inclusive and exclusive processes in deep-inelastic lepton scattering, helping to clarify the spin puzzle of the nucleon.
CP VIOLATION IN B DECAYS
Authors:   FOR THE BABAR COLLABORATION., BIASINI MAURIZIO
Published: February 2007

We present recent results on CP violation in the B meson system from the BABAR experiment at the PEP II asymmetric e+e- collider. We discuss the study of CP violation in B-mixing and present measurements of unitarity-triangle angles α, β, and constraints on γ.
NEAR THRESHOLD η MESON PRODUCTION IN dp COLLISIONS
Authors:   COSY-11 COLLABORATION., Piskor-Ignatowicz C. , Smyrski J. , Moskal P. , Adam H.-H. , Budzanowski A. , Czerwiński E. , Czyżykiewicz R. , Gil D. , Grzonka D. , Janusz M. , Jarczyk L. , Kamys B. , Khoukaz A. , Klaja P. , Majewski J. , Oelert W. , Przerwa J. , Ritman J. , Rożek T. , Sefzick T. , Siemaszko M. , Täschner A. , Winter P. , Wolke M. , Wüstner P. , Zipper W.
Published: February 2007

Preliminary results of recent measurements of the near threshold η meson production in the dp → dpη reaction are presented. The experiment was performed at the COSY-Juelich accelerator with the use of the COSY-11 detection system. Data were taken for three values of deuteron beam momenta corresponding to excess energies of 3.2, 6.1 and 9.2 MeV. The energy dependence of the total cross section confirms a strong effect of the final state interaction.