bluuebunny/crossref_metadata_2025 huggingface dataset:
Stabilization of dissolved organic matter by aluminium: a toxic effect or stabilization through precipitation?
Authors: Scheel T. , Jansen B. , Van Wijk A. J. , Verstraten J. M. , Kalbitz K.
Published: October 2008

Carbon mineralization in acidic forest soils can be retarded by large concentrations of aluminium (Al). However, it is still unclear whether Al reduces C mineralization by direct toxicity to microorganisms or by decreased bioavailability of organic matter (OM) because dissolved organic matter (DOM) is precipitated by Al. We conducted an incubation experiment (6 weeks) with two DOM solutions (40 mg C litre−1) derived from two acidic forests and possessing large differences in composition. Aluminium was added to the solutions in realistic ranges for acidic soils (1.6–24 mg Al litre−1) at pHs of 3.8 and 4.5, to achieve differences in Al speciation. We determined different Al species, including the potentially toxic Al3+, by Diffusive Gradients in Thin Films (DGT) to evaluate toxic effects on microorganisms. Precipitation of OM increased with larger amounts of added Al and higher pH, and we measured a larger fraction of dissolved ‘free’ Al at pH 3.8 than at pH 4.5. Organic matter degradation decreased significantly with Al addition, and we found more organic matter degraded at pH 3.8 than at pH 4.5 for the respective Al additions. Consequently, the observed reduction in OM degradation (i.e. stabilization) cannot be explained by toxic effects of ‘free’ Al. However, C stabilization correlated significantly with C precipitation. The pH did not influence C stabilization directly, but determined the amount of C being precipitated. Phosphorus was removed along with OM by precipitation, which possibly also affected C stabilization. We conclude that C stabilization upon Al addition did not result from toxic effects, but was caused by reduced bioavailability of OM after its precipitation. The reduction in OM degradation by 65% is of great relevance for the overall C stabilization in acidic forest soils. Increasing pH and decreasing Al concentrations upon recovery from acidic deposition should therefore not result in decreased stabilization of precipitated OM.
Drought‐induced tree death in savanna
Authors: FENSHAM R. J. , FAIRFAX R. J. , WARD D. P.
Published: October 2008

Increasing densities of woody plants in savannas has been attributed to both elevated atmospheric CO2 and reduced burning with grazing management, such that the biome could represent a substantial carbon sink. However, we show that extreme droughts (less than two‐thirds expected rainfall over 3 years) occur in the drier half of the savanna biome and can cause substantial tree death. An Australian case study reveals that a net increase in tree cover over five decades of above‐average rainfall was offset by sudden tree death during drought. The relationship between woody cover change and rainfall is moderated by competition with growth being facilitated by low woody cover and drought‐induced death more likely as the woody component of savanna increases. The results are not supportive of a sustained increase in the woody component of xeric savannas resulting from CO2 fertilization or land management. Extensive tree death in savanna regions will become a stark consequence of climate change if predictions of increasing severity and frequency of drought are realized.
Mitigation of adverse effects of rising CO2 on a planktonic herbivore by mixed algal diets
Authors: URABE JOTARO , WAKI NAOKO
Published: October 2008

Putative future increase in atmospheric CO2 is expected to adversely affect herbivore growth due to decrease in contents of key nutrients such as nitrogen and phosphorus (P) relative to carbon in primary producers including plant and algal species. However, as many herbivores are polyphagous and as the response of primary producers to elevated CO2 is highly species‐specific, effects of elevated CO2 on herbivore growth may differ between feeding conditions with monospecific and multiproducer diets. To examine this possibility, we performed CO2 manipulation experiments under a P‐limited condition with a planktonic herbivore, Daphnia, and three algal species, Scenedesmus obliquus (green algae), Cyclotella sp. (diatoms) and Synechococcus sp. (cyanobacteria). Semibatch cultures with single algal species (monocultures) and multiple algal species (mixed cultures) were grown at ambient (360 ppm) and high CO2 levels (2000 ppm) that were within the natural range in lakes. Both in the mono‐ and mixed cultures, algal steady state abundance increased but algal P : C and N : C ratios decreased when they were grown at high CO2. As expected, Daphnia fed monospecific algae cultured at high CO2 had decreased growth rates despite increased algal abundance. However, when fed mixed algae cultured at high CO2, especially consisting of diatoms and cyanobacteria or the three algal species, Daphnia maintained high growth rates despite lowered P and N contents relative to C in the algal diets. These results imply that algal diets composed of multiple species can mitigate the adverse effects of elevated CO2 on herbivore performance, although the magnitude of this mitigation depends on the composition of algal species involved in the diets.
Elevated air temperature alters an old‐field insect community in a multifactor climate change experiment
Authors: VILLALPANDO SHAWN N. , WILLIAMS RAY S. , NORBY RICHARD J.
Published: October 2008

To address how multiple, interacting climate drivers may affect plant–insect community associations, we sampled insects that naturally colonized a constructed old‐field plant community grown for over 2 years under simultaneous CO2, temperature, and water manipulation. Insects were sampled using a combination of sticky traps and vacuum sampling, identified to morphospecies and the insect community with respect to abundance, richness, and evenness quantified. Individuals were assigned to four broad feeding guilds in order to examine potential trophic level effects. Although there were occasional effects of CO2 and water treatment, the effects of warming on the insect community were large and consistent. Warming significantly increased Order Thysanoptera abundance and reduced overall morphospecies richness and evenness. Nonmetric multidimensional scaling found that only temperature affected insect community composition, while a Sørensen similarity index showed less correspondence in the insect community between temperature treatments compared with CO2 or soil water treatments. Within the herbivore guild, elevated temperature significantly reduced richness and evenness. Corresponding reductions of diversity measures at higher trophic levels (i.e. parasitoids), along with the finding that herbivore richness was a significant predictor of parasitoid richness, suggest trophic‐level effects within the insect community. When the most abundant species were considered in temperature treatments, a small number of species increased in abundance at elevated temperature, while others declined compared with ambient temperature. Effects of temperature in the dominant insects demonstrated that treatment effects were limited to a relatively small number of morphospecies. Observed effects of elevated CO2 concentration on whole‐community foliar N concentration did not result in any effect on herbivores, which are probably the most susceptible guild to changes in plant nutritional quality. These results demonstrate that climatic warming may alter certain insect communities via effects on insect species most responsive to a higher temperature, contributing to a change in community structure.
Predominant role of water in regulating soil and microbial respiration and their responses to climate change in a semiarid grassland
Authors: LIU WEIXING , ZHANG ZHE , WAN SHIQIANG
Published: October 2008

Climate change can profoundly impact carbon (C) cycling of terrestrial ecosystems. A field experiment was conducted to examine responses of total soil and microbial respiration, and microbial biomass to experimental warming and increased precipitation in a semiarid temperate steppe in northern China since April 2005. We measured soil respiration twice a month over the growing seasons, soil microbial biomass C (MBC) and N (MBN), microbial respiration (MR) once a year in the middle growing season from 2005 to 2007. The results showed that interannual variations in soil respiration, MR, and microbial biomass were positively related to interannual fluctuations in precipitation. Laboratory incubation with a soil moisture gradient revealed a constraint of the temperature responses of MR by low soil moisture contents. Across the 3 years, experimental warming decreased soil moisture, and consequently caused significant reductions in total and microbial respiration, and microbial biomass, suggesting stronger negatively indirect effects through warming‐induced water stress than the positively direct effects of elevated temperature. Increased evapotranspiration under experimental warming could have reduced soil water availability below a stress threshold, thus leading to suppression of plant growth, root and microbial activities. Increased precipitation significantly stimulated total soil and microbial respiration and all other microbial parameters and the positive precipitation effects increased over time. Our results suggest that soil water availability is more important than temperature in regulating soil and microbial respiratory processes, microbial biomass and their responses to climate change in the semiarid temperate steppe. Experimental warming caused greater reductions in soil respiration than in gross ecosystem productivity (GEP). In contrast, increased precipitation stimulated GEP more than soil respiration. Our observations suggest that climate warming may cause net C losses, whereas increased precipitation may lead to net C gains in the semiarid temperate steppe. Our findings highlight that unless there is concurrent increase in precipitation, the temperate steppe in the arid and semiarid regions of northern China may act as a net C source under climate warming.
Hope, expectations and recovery from illness: a narrative synthesis of qualitative research
Authors: Wiles Rose , Cott Cheryl , Gibson Barbara E.
Published: October 2008

Aim.  This paper is a report of a narrative literature review conducted to explore how expectations and wants are distinguished in empirical research on hope and illness and the related issues of realistic hope and temporality.

Background.  Particularized hope has been identified as comprising wants and expectations. The distinction is important in relation to debates around ‘realistic’ hopes, the temporal dimension of hope and hope‐sustaining strategies.

Data sources.  A systematic search of the literature was undertaken for qualitative research papers published between January 1996 and July 2007 relating to hope and recovery in adults with physical ill health. Seven papers were identified.

Review methods.  A narrative synthesis approach was adopted and the papers were appraised for quality using the Critical Appraisal Skills Programme method. Textual descriptions and tabulation were used to compare central themes and thematic analysis was used to explore the findings.

Results.  A lack of conceptual clarity in relation to hope as a want or an expectation was identified. Healthcare professionals’ role in encouraging ‘realistic’ hopes emerged as problematic because of the lack of understanding about the possible benefits of hope and difficulties in identifying ‘realistic’ hopes. There has been limited research exploring temporality and the impact of hope‐sustaining activities.

Conclusion.  The lack of clarity about particularized hope, its dimensions, properties or different forms limits knowledge about the conditions under which hope is a positive force versus when it can be damaging. Distinguishing conceptually between hope as a want and hope as an expectation has potential value in improving healthcare practice and informing future investigations.
Cross‐disciplinary demands of multihost pathogens
Authors: HAYDON DANIEL T.
Published: October 2008

The dynamics of infectious disease spread depend on host population contact structure. Heterogeneities in this contact structure can arise from various forms of demographic and spatial phenomena. Craft et al. (this issue) have constructed an exploratory simulation model of the spread of canine distemper virus through a multispecies carnivore community. Each species in this community is modelled with a contact structure reflecting host social organization, ranging behaviour, and likely interspecific contact patterns. The results are used to infer the possible roles of different species in determining the observed spatio‐temporal incidence of canine distemper virus in Serengeti lions during an outbreak in 1993–94.
The impact of lifestyle on the physical fitness of primary school children
Authors: Chung Joanne WY , Chung Louisa MY , Chen Bob
Published: October 2008

Aims.  To compare the physical fitness levels of Hong Kong and mainland Chinese school children and to study the association between any differences and their respective lifestyles.

Background.  Genes and lifestyle are both factors contributing to health. Hong Kong is a Chinese city with distinctive lifestyle features such as a different diet and different entertainment and education from the rest of China. Using samples of the same ethnicity and investigating differences in the physical fitness parameters between Hong Kong and mainland Chinese school children might reveal the impact of some lifestyle factors on health.

Design.  Survey.

Method.  Primary school children (n = 522) were recruited. Demographic data were collected by questionnaire. Physical fitness tests were carried out.

Results.  Significant differences were found in height, body weight, sit and reach, long jump, running 50 m and lung capacity. Hong Kong children were found to be taller and heavier at ages 6 and 7, but heavier with similar height to that of mainland children at ages 8–12. Other results showed better physical fitness on the part of mainland children.

Discussion.  Although the people of Hong Kong share the same ethnicity as the majority of mainland Chinese, the eastern‐mixed‐with‐western diet, education and entertainment of Hong Kong children differ greatly. The findings in terms of physical fitness revealed variations in body build, flexibility, cardiovascular function and muscle power between the two groups.

Conclusion.  Lifestyle could possibly be a key factor and predictor of physical fitness, providing strong evidence to support the interaction between lifestyle and genes in their impact on our health.

Relevance to clinical practice.  Lifestyle could possibly be a key factor and predictor of physical fitness and health outcomes. The finding of this study may enhance the identification of healthy lifestyle which may improve health outcomes in children.
Swedish and Chinese nurses’ conceptions of ethical problems: a comparative study
Authors: Silén Marit , Tang Ping Fen , Ahlström Gerd
Published: October 2008

Aim.  To investigate Swedish and Chinese nurses’ conceptions of ethical problems and workplace stress and ascertain whether there are differences between the nurses in the two countries and between types of clinics.

Background.  Nursing can be regarded as an ethical practice and ethical problems are one type of problems nurses have to deal with.

Design.  The research design was comparative and quantitative.

Methods.  A questionnaire was used. The study was carried out at one hospital in China and two hospitals in Sweden. One hundred and thirty‐six Chinese nurses and 137 Swedish nurses participated.

Results.  There was a statistical difference between nurses working in the different countries regarding commonest stated ethical problem. The Swedish nurses indicated a greater number of ethical problems than the Chinese nurses. The latter felt irritated, dissatisfied or sad at work or after work more often than the Swedish nurses. Forty‐one per cent of the nurses in both countries thought there was a modest or rather big difference between the current and the desired quality of nursing.

Conclusions.  The findings were partially the same in the two countries and this underlines the importance of looking at ethical problems from an organisational perspective.

Relevance to clinical practice.  The findings also show the need for a reduction of nurses’ workload as well as the importance of assuring that nurses have the knowledge they need to carry out their work. The communication between nurses and other members of the health‐care team, patients and relatives also needs to be improved.
Injured road users’ health‐related quality of life after telephone intervention: a randomised controlled trial
Authors: Franzén Carin , Brulin Christine , Stenlund Hans , Björnstig Ulf
Published: October 2008

Objective.  To investigate whether nursing intervention via telephone follow‐up can affect health‐related quality of life among road users in the postinjury phase.

Background.  Injuries in the traffic environment often cause both physical impairment and psychological trauma. Therefore, it is important to investigate whether nursing via telephone follow‐up after discharge could affect health‐related quality of life among injured road users.

Design.  A randomised controlled study.

Method.  Between April 2003–April 2005, car occupants, cyclists and pedestrians, aged 18–70 years, all injured in the traffic environment, were randomly assigned to an intervention (n = 288) or control group (n = 280). All patients were initially managed by one emergency department with the intervention group being followed up by nurse led telephone follow‐up three weeks after discharge, while the control group did not receive any telephone follow‐up. Data were collected from a mail survey using the non‐disease‐specific health‐related quality of life instrument EQ5D, at baseline and after six months.

Results.  In general, the intervention group rated significantly higher health‐related quality of life than the control group. This difference was most pronounced in the group of those provided with advice as part of telephone follow‐up and significantly for the general health status. Car occupants gained most advantage from the nursing telephone follow‐up, with significantly lower problems in the dimensions of pain/discomfort and usual activities.

Conclusion.  Nursing intervention via telephone follow‐up was effective at increasing the health‐related quality of life of injured road users. Early identification of the concerns of the injured and specific advice provided by the intervening nurse seems to be of greatest weight. Thus, more research is needed regarding the usefulness of early support and the advantage of this from a health economic perspective.

Relevance to clinical practice.  There is a need for changes in attitudes and working routines to identify individuals with low health‐related quality of life and to give more extensive support from this point of view.
Factors associated with the prevalence of violent behaviour among residents living in nursing homes
Authors: Isaksson Ulf , Åström Sture , Sandman Per‐Olof , Karlsson Stig
Published: October 2008

Aim.  The aim of this study was to investigate the associations between environmental and organisational factors as well as resident and caregiver characteristics in nursing home wards with a high respectively low prevalence of residents with violent behaviour.

Background.  Earlier studies have indicated that different factors are related to violent behaviour among residents living in nursing homes, such as environmental and organisational variations, and resident and caregiver characteristics. However, few studies have simultaneously examined the relationship between these factors.

Design.  A cross‐sectional descriptive survey design.

Methods.  The study was performed in 10 nursing homes consisting of 33 wards. Data were collected using the Multi‐Dimensional Dementia Assessment Scale and the Geriatric Rating Scale. Variables concerning organisation and environment were gathered by means of a questionnaire. Differences between wards with high (HPW) or low prevalence of violence (LPW) were analysed.

Results.  In HPWs, the prevalence of behaviour and psychiatric symptoms, residents needing assistance with dressing and psychological workload were found to be higher, while job satisfaction was lower compared to LPWs. This study has also shown that caregivers in HPWs had less experience of working with older people and they experienced their working climate as less positive. Furthermore, HPWs had more residents, lower caregiver‐to‐resident ratio and longer corridors, and caregivers in these wards experienced more difficulties to supervise the residents.

Conclusion.  This study has shown that the prevalence of residents with violent behaviour is significantly associated with other behavioural and psychiatric symptoms and ADL (activities of daily life)‐functions, as well as caregivers’ experiences of job satisfaction and psychological workload.

Relevance to clinical practice.  This study underlines the importance of a multifactorial approach to understand the prevalence of violent behaviour, including the physical environment, organisational factors, as well as characteristics of the resident and the caregiver.
Development and psychometric testing of the Cancer Knowledge Scale for Elders
Authors: Su Ching‐Ching , Chen Yuh‐Min , Kuo Bo‐Jein
Published: October 2008

Aim.  To develop the Cancer Knowledge Scale for Elders and test its validity and reliability.

Background.  The number of elders suffering from cancer is increasing. To facilitate cancer prevention behaviours among elders, they shall be educated about cancer‐related knowledge. Prior to designing a programme that would respond to the special needs of elders, understanding the cancer‐related knowledge within this population was necessary. However, extensive review of the literature revealed a lack of appropriate instruments for measuring cancer‐related knowledge. A valid and reliable cancer knowledge scale for elders is necessary.

Design.  A non‐experimental methodological design was used to test the psychometric properties of the Cancer Knowledge Scale for Elders.

Methods.  Item analysis was first performed to screen out items that had low corrected item‐total correlation coefficients. Construct validity was examined with a principle component method of exploratory factor analysis. Cancer‐related health behaviour was used as the criterion variable to evaluate criterion‐related validity. Internal consistency reliability was assessed by the KR‐20. Stability was determined by two‐week test–retest reliability.

Results.  The factor analysis yielded a four‐factor solution accounting for 49·5% of the variance. For criterion‐related validity, cancer knowledge was positively correlated with cancer‐related health behaviour (r = 0·78, p < 0·001). The KR‐20 coefficients of each factor were 0·85, 0·76, 0·79 and 0·67 and 0·87 for the total scale. Test–retest reliability over a two‐week period was 0·83 (p < 0·001).

Conclusion.  This study provides evidence for content validity, construct validity, criterion‐related validity, internal consistency and stability of the Cancer Knowledge Scale for Elders. The results show that this scale is an easy‐to‐use instrument for elders and has adequate validity and reliability.

Relevance to clinical practice.  The scale can be used as an assessment instrument when implementing cancer education programmes for elders. It can also be used to evaluate the effects of education programmes.
Older people and inflammatory bowel disease: a systematic review
Authors: Smith Graeme D , Watson Roger , Thompson David R
Published: October 2008

Aims and objectives.  To review the literature on inflammatory bowel disease in older and younger people and to identify whether they included a nursing or psychosocial perspective, or were informed by theories of ageing.

Background.  Inflammatory bowel disease, manifested as Crohn’s disease and ulcerative colitis, affects younger and older people and is associated with a range of psychosocial factors. Nurses have an important role to play in caring for people with inflammatory bowel disease.

Methods.  A systematic review of literature related to inflammatory bowel disease and older people was carried out using the MEDLINE, CINAHL EMBASE and Cochrane databases between 1990–2006.

Conclusions.  Generally speaking, the clinical features of inflammatory bowel disease are similar in younger and older people, as are indications for surgery, survival and the usual wide spectrum of severity of disease. Corticosteroid treatment carries additional risk for older people. The studies used both retrospective and prospective designs, with the former using patient records, and the latter using follow‐up of patients with inflammatory bowel disease. Sample sizes were adequate for statistical analyses but there was no reference to reliability or validity of data collection methods. None of the studies considered psychosocial aspects, or the role of nurses in caring for people with inflammatory bowel disease. A specific gerontological perspective was lacking from the papers reviewed. While the clinical features of inflammatory bowel disease are similar in younger and older people, with the bimodal distribution of age of onset of inflammatory bowel disease, the possibility exists that quality of life and adjustment in older people depend on age of onset. This has not been investigated. Future lines of enquiry taking psychosocial aspects of inflammatory bowel disease into account in older people are explored.

Relevance to clinical practice.  Nurses play an increasingly important role in the assessment and management of inflammatory bowel disease patients. Little is known about factors which could predict poorer psychosocial health and the impact non‐intestinal manifestations may have on this in older people with inflammatory bowel disease.
The relationship between coping and psychological and physical adjustment in rheumatoid arthritis: a literature review
Authors: Ramjeet Janet , Smith Jane , Adams Malcolm
Published: October 2008

Aim. This systematic review examines how specific coping strategies are associated with psychological and physical outcomes in rheumatoid arthritis.

Background and methods. Rheumatoid arthritis is a long‐term condition that people cope with but it is unclear whether specific coping strategies have an effect on mood and function. Therefore a systematic review was undertaken of the coping with arthritis literature and 174 studies were initially included. Further examination determined that 31 studies (11 longitudinal and 20 cross sectional) were finally included in the review. The 31 studies were clinically and methodologically diverse; therefore the analysis of results was a qualitative synthesis. Coping strategies that contributed to the prediction of outcomes were allocated to a new structure for the classification of coping.

Results. The results demonstrated there was not sufficient, consistent evidence to support the overall view that individual coping strategies contributed to longitudinal outcomes in rheumatoid arthritis. However, major differences in the design of included studies may have hindered the comparison of results. There was some evidence from longitudinal studies that patients who used resting, inactivity, etc. (helplessness category) experienced negative outcomes. Avoidance (escape) was the most common overall category associated with predominantly negative outcomes in both cross‐sectional and longitudinal studies.

Conclusions. There was generally limited evidence to suggest an association between coping strategies and outcomes but the design of studies and the lack of clarity about coping strategies were identified as problems. This study used a new framework for the conceptualisation of coping strategies, thus contributing to further examining the utility of coping strategies and contributing to their redefinition.

Relevance to clinical practice. The use of helplessness (inactivity and passive coping) and escape/avoidant coping strategies, including denial and wishful thinking, could be identified and addressed by nurses and other health professionals to reduce the associated negative outcomes.
Antacids in the initial management of metallic zinc ingestion in dogs
Authors: Van Der MERWE D. , TAWDE S.
Published: October 2008

Zinc poisoning in dogs, following ingestion of post‐1982 U.S. one cent coins is an increasingly common toxicological syndrome causing gastrointestinal abnormalities, hemolytic anemia, pancreatitis and renal failure. Thermodynamic laws predict that the rate of the chemical reaction between HCl and metallic zinc, which releases absorbable zinc anions, is dependent on pH. The significance of the relation between pH and dissolution is, however, apparently contradicted by the fact that recent veterinary toxicology texts are silent on the use of antacids in the early management of zinc ingestion in dogs. A series of experiments were conducted to test the hypotheses that the degree to which zinc dissolution is pH dependent is likely to be of clinical importance and that the use of antacids will be of benefit in preventing zinc poisoning in dogs that had ingested metallic zinc. Zinc dissolution was strongly dependent on pH in an exponential manner, indicating that clinically achievable upward adjustment of gastric pH using antacids is likely to have significant effects on the rate of zinc absorption in dogs. These data clearly support the use of antacids during the initial treatment of metallic zinc ingestion in dogs.
Functional analysis of the large periplasmic loop of the Escherichia coli K‐12 WaaL O‐antigen ligase
Authors: Pérez José M. , McGarry Megan A. , Marolda Cristina L. , Valvano Miguel A.
Published: October 2008

WaaL is a membrane enzyme implicated in ligating undecaprenyl‐diphosphate (Und‐PP)‐linked O antigen to lipid A‐core oligosaccharide. We determined the periplasmic location of a large (EL5) and small (EL4) adjacent loops in the Escherichia coli K‐12 WaaL. Structural models of the EL5 from the K‐12, R1 and R4 E. coli ligases were generated by molecular dynamics. Despite the poor amino acid sequence conservation among these proteins, the models afforded similar folds consisting of two pairs of almost perpendicular α‐helices. One α‐helix in each pair contributes a histidine and an arginine facing each other, which are highly conserved in WaaL homologues. Mutations in either residue rendered WaaL non‐functional, since mutant proteins were unable to restore O antigen surface expression. Replacements of residues located away from the putative catalytic centre and non‐conserved residues within the centre itself did not affect ligation. Furthermore, replacing a highly conserved arginine in EL4 with various amino acids inactivates WaaL function, but functionality reappears when the positive charge is restored by a replacement with lysine. These results lead us to propose that the conserved amino acids in the two adjacent periplasmic loops could interact with Und‐PP, which is the common component in all WaaL substrates.
Phytophthora infestans in a subtropical region: survival on tomato debris, temporal dynamics of airborne sporangia and alternative hosts
Authors: Lima M. A. , Maffia L. A. , Barreto R. W. , Mizubuti E. S. G.
Published: October 2008

Little is known about inoculum dynamics of late blight caused by Phytophthora infestans in tropical/subtropical areas, particularly in Brazil. The objectives of the present study were to assess (i) the survival of the pathogen on stems, leaflets and tomato fruits, either buried or not in soil; (ii) the pathogenicity of P. infestans to mostly solanaceous plant species commonly found in Brazil that could act as inoculum reservoir; and (iii) the temporal dynamics of airborne sporangia. Phytophthora infestans survived in tomato plant parts for less than 36 days under greenhouse and field conditions. In greenhouse tests, pathogen structures were detected earlier on crop debris kept in dry than in wet soil conditions. Isolates of two clonal lineages of P. infestans, US‐1 from tomato, and BR‐1 from potato, were inoculated on 43 plant species. In addition to potato and tomato, Petunia × hybrida and Nicotiana benthamiana were susceptible to the pathogen. Airborne inoculum was monitored with Rotorod and Burkard spore traps as well as with tomato and potato trap plants. Sporangia were sampled in most weeks throughout 2004 and in the first two weeks of 2005. Under tropical/subtropical conditions, airborne inoculum is abundant and is more important to late blight epidemics than inoculum from crop debris or alternative hosts.
Quantitative evolution of aggressiveness of powdery mildew under two‐cultivar barley mixtures
Authors: Marshall B. , Newton A. C. , Zhan J.
Published: October 2008

The effects of cultivar mixtures on the evolution of aggressiveness of barley powdery mildew (Blumeria graminis f.sp. hordei) were modelled. It was found that the rate and direction of evolution of pathogen aggressiveness in a race‐non‐specific system and value at equilibrium, depends on initial resistance levels, proportions of component cultivars, autodeposition rates, the relative magnitude of the benefit of autoinfection, and the cost of alloinfection of spores. In the model, mixing cultivars in any proportions tended to reduce the aggressiveness of pathogens at equilibrium compared with pure stands, but this effect decreased when two mixture components were extremely unbalanced in proportion. Under low and medium autodeposition rates, the best control of the evolution of the pathogen was achieved by mixing two components in roughly equal proportions. The magnitude of aggressiveness at equilibrium increased as autodeposition rates increased. Though the level of initial resistance of mixture components did not have an impact on the aggressiveness of pathogens at equilibrium, it strongly influenced the transient values of aggressiveness and therefore the total amount of disease caused over an evolutionary period. The cost to the pathogen of alloinfection and benefit of autoinfection per se did not affect the final level of aggressiveness, but did affect the time to reach equilibrium. However, the ratio of the cost to the benefit did influence the final aggressiveness of the pathogen.
The Pseudomonas syringae type III effector AvrRpm1 induces significant defenses by activating the Arabidopsis nucleotide‐binding leucine‐rich repeat protein RPS2
Authors: Kim Min Gab , Geng Xueqing , Lee Sang Yeol , Mackey David
Published: October 2008

Plant disease resistance (R) proteins recognize potential pathogens expressing corresponding avirulence (Avr) proteins through ‘gene‐for‐gene’ interactions. RPM1 is an Arabidopsis R‐protein that triggers a robust defense response upon recognizing the Pseudomonas syringae effector AvrRpm1. Avr‐proteins of phytopathogenic bacteria include type III effector proteins that are often capable of enhancing virulence when not recognized by an R‐protein. In rpm1 plants, AvrRpm1 suppresses basal defenses induced by microbe‐associated molecular patterns. Here, we show that expression of AvrRpm1 in rpm1 plants induced PR‐1, a classical defense marker, and symptoms including chlorosis and necrosis. PR‐1 expression and symptoms were reduced in plants with mutations in defense signaling genes (pad4, sid2, npr1, rar1, and ndr1) and were strongly reduced in rpm1 rps2 plants, indicating that AvrRpm1 elicits defense signaling through the Arabidopsis R‐protein, RPS2. Bacteria expressing AvrRpm1 grew more on rpm1 rps2 than on rpm1 plants. Thus, independent of its classical ‘gene‐for‐gene’ activation of RPM1, AvrRpm1 also induces functionally relevant defenses that are dependent on RPS2. Finally, AvrRpm1 suppressed host defenses and promoted the growth of type III secretion mutant bacteria equally well in rps2 and RPS2 plants, indicating that virulence activity of over‐expressed AvrRpm1 predominates over defenses induced by weak activation of RPS2.
Serological prevalence of echinococcosis and risk factors for infection among children in rural communities of southern Ningxia, China
Authors: Yang Yu Rong , Craig Philip S. , Vuitton Dominique A. , Williams Gail M. , Sun Tao , Liu Tian Xi , Boufana Belgees , Giraudoux Patrick , Teng Jing , Li Yanbin , Huang Ling , Zhang Wei , Jones Malcolm K. , McManus Donald P.
Published: October 2008

Objective To assess the usefulness of serology as an indicator ofEchinococcustransmission for developing preventive measures against echinococcosis in rural communities.

Methods Cross‐sectional survey in 2002 among 861 children aged 7 to 18 years in Xiji County, Ningxia, China. Before ultrasound abdominal examination, a questionnaire was used to identify socioeconomic, sanitary and hygiene risk factors for echinococcal infection; filter paper blood samples were collected from each child for specific antibody detection using EmP (Echinococcus multilocularis) and EgB (Echinococcus granulosus) antigens.

Results Transmission of bothE. multilocularisandE. granulosusoccur in this area. Serological prevalence was far higher than disease prevalence in this age range. We found no gender‐related differences of seroprevalence among the children, suggesting an equal chance of exposure to echinococcal egg‐contaminated environments. The seroprevalence distribution was associated with changes in the ecology of wild hosts forE. multiloculariscontamination, and with changes in socio‐geographic features of the communities forE. granulosuscontamination.

Conclusions Serological data obtained for children in mass surveys of echinococcosis appear to be a comprehensive and useful tool to monitor changes of transmission dynamics in humans and provide ‘warning signals’ to decision makers for the instigation of specific control measures against the disease.
Hydroxyzine and cetirizine pharmacokinetics and pharmacodynamics after oral and intravenous administration of hydroxyzine to healthy dogs
Authors: Bizikova Petra , Papich Mark G. , Olivry Thierry
Published: October 2008

Pharmacokinetic parameters of hydroxyzine and its active metabolite cetirizine were determined after oral and intravenous administration of 2 mg kg−1 of hydroxyzine to six healthy dogs. Plasma drug levels were determined with high‐pressure liquid chromatography. Pharmacodynamic studies evaluated the suppressive effect on histamine and anticanine IgE‐mediated cutaneous wheal formation. Pharmacokinetic and pharmacodynamic correlations were determined with computer modelling. The mean systemic availability of oral hydroxyzine was 72%. Hydroxyzine was rapidly converted to cetirizine regardless of the route of administration. The mean area‐under‐the‐curve was eight and ten times higher for cetirizine than hydroxyzine after intravenous and oral dosing, respectively. After oral administration of hydroxyzine, the mean peak concentration of cetirizine was approximately 2.2 µg mL−1 and that of hydroxyzine 0.16 µg mL−1. The terminal half‐life for cetirizine varied between 10 and 11 h after intravenous and oral administration of hydroxyzine. A sigmoidal relationship was fit to the data comparing cetirizine plasma concentration to wheal suppression. Maximum inhibition (82% and 69% for histamine and anticanine IgE‐mediated skin reactions, respectively) was observed during the first 8 h, which correlated with a plasma concentration of cetirizine greater than 1.5 µg mL−1. Pharmacological modelling suggested that increasing either hydroxyzine dosages or frequencies of administration would not result in histamine inhibition superior to that obtained with twice daily hydroxyzine at 2 mg kg−1. In conclusion, there was rapid conversion of hydroxyzine to cetirizine. The reduction of wheal formation appeared almost entirely due to cetirizine. Pharmacodynamic modelling predicted that maximal antihistamine effect would occur with twice daily oral administration of hydroxyzine at 2 mg kg−1.
Impulsivity as a determinant and consequence of drug use: a review of underlying processes
Authors: de Wit Harriet
Published: October 2008

Impulsive behaviors are closely linked to drug use and abuse, both as contributors to use and as consequences of use. Trait impulsivity is an important determinant of drug use during development, and in adults momentary ‘state’ increases in impulsive behavior may increase the likelihood of drug use, especially in individuals attempting to abstain. Conversely, acute and chronic effects of drug use may increase impulsive behaviors, which may in turn facilitate further drug use. However, these effects depend on the behavioral measure used to assess impulsivity. This article reviews data from controlled studies investigating different measures of impulsive behaviors, including delay discounting, behavioral inhibition and a newly proposed measure of inattention. Our findings support the hypothesis that drugs of abuse alter performance across independent behavioral measures of impulsivity. The findings lay the groundwork for studying the cognitive and neurobiological substrates of impulsivity, and for future studies on the role of impulsive behavior as both facilitator and a result of drug use.
Heavy drinking relates to positive valence ratings of alcohol cues
Authors: Pulido Carmen , Mok Alex , Brown Sandra A. , Tapert Susan F.
Published: October 2008

A positive family history of alcohol use disorders (FH) is a robust predictor of personal alcohol abuse and dependence. Exposure to problem‐drinking models is one mechanism through which family history influences alcohol‐related cognitions and drinking patterns. Similarly, exposure to alcohol advertisements is associated with alcohol involvement and the relationship between affective response to alcohol cues and drinking behavior has not been well established. In addition, the collective contribution that FH, exposure to different types of problem‐drinking models (e.g. parents, peers) and personal alcohol use have on appraisal of alcohol‐related stimuli has not been evaluated with a large sample. We investigated the independent effects of FH, exposure to problem‐drinking models and personal alcohol use on valence ratings of alcohol pictures in a college sample. College students (n = 227) completed measures of personal drinking and substance use, exposure to problem‐drinking models, FH and ratings on affective valence of 60 alcohol pictures. Greater exposure to non‐familial problem‐drinkers predicted greater drinking among college students (β = 0.17, P < 0.01). However, personal drinking was the only predictor of valence ratings of alcohol pictures (β = −0.53, P < 0.001). Personal drinking level predicted valence ratings of alcohol cues over and above FH, exposure to problem‐drinking models and demographic characteristics. This suggests that positive affective responses to alcohol pictures are more a function of personal experience (i.e. repeated heavy alcohol use) than vicarious learning.
Proof‐of‐concept human laboratory study for protracted abstinence in alcohol dependence: effects of gabapentin
Authors: Mason Barbara J. , Light John M. , Williams Lauren D. , Drobes David J.
Published: October 2008

There is a need for safe medications that can effectively support recovery by treating symptoms of protracted abstinence that may precipitate relapse in alcoholics, e.g. craving and disturbances in sleep and mood. This proof‐of‐concept study reports on the effectiveness of gabapentin 1200 mg for attenuating these symptoms in a non‐treatment‐seeking sample of cue‐reactive, alcohol‐dependent individuals. Subjects were 33 paid volunteers with current Diagnostic and Statistical Manual of Mental Disorders‐IV alcohol dependence and a strength of craving rating 1 SD or greater for alcohol than water cues. Subjects were randomly assigned to gabapentin or placebo for 1 week and then participated in a within‐subjects trial where each was exposed to standardized sets of pleasant, neutral and unpleasant visual stimuli followed by alcohol or water cues. Gabapentin was associated with significantly greater reductions than placebo on several measures of subjective craving for alcohol as well as for affectively evoked craving. Gabapentin was also associated with significant improvement on several measures of sleep quality. Side effects were minimal, and gabapentin effects were not found to resemble any major classes of abused drugs. Results suggest that gabapentin may be effective for treating the protracted abstinence phase in alcohol dependence and that a randomized clinical trial would be an appropriate next step. The study also suggests the value of cue‐reactivity studies as proof‐of‐concept screens for potential antirelapse drugs.
Identifying the neural circuitry of alcohol craving and relapse vulnerability
Authors: Heinz Andreas , Beck Anne , Grüsser Sabine M. , Grace Anthony A. , Wrase Jana
Published: October 2008

With no further intervention, relapse rates in detoxified alcoholics are high and usually exceed 80% of all detoxified patients. It has been suggested that stress and exposure to priming doses of alcohol and to alcohol‐associated stimuli (cues) contribute to the relapse risk after detoxification. This article focuses on neuronal correlates of cue responses in detoxified alcoholics. Current brain imaging studies indicate that dysfunction of dopaminergic, glutamatergic and opioidergic neurotransmission in the brain reward system (ventral striatum including the nucleus accumbens) can be associated with alcohol craving and functional brain activation in neuronal systems that process attentional relevant stimuli, reward expectancy and experience. Increased functional brain activation elicited by such alcohol‐associated cues predicted an increased relapse risk, whereas high brain activity elicited by affectively positive stimuli may represent a protective factor and was correlated with a decreased prospective relapse risk. These findings are discussed with respect to psychotherapeutic and pharmacological treatment options.
Anticaries effect of compounds extracted from Galla Chinensis in a multispecies biofilm model
Authors: Xie Q. , Li J. , Zhou X.
Published: October 2008

Introduction:  Galla Chinensis is a leaf gall known to have some antibacterial effects. Using an in vitro biofilm model of dental plaque, the present study aimed to evaluate the anticaries effects of Galla Chinensis and its chemical fractions.

Methods:  A four‐organism bacterial consortium (Streptococcus sanguis, Streptococcus mutans, Actinomyces naeslundii, Lactobacillus rhamnosus) was grown on hydroxyapatite (HA) discs, bovine enamel blocks, and glass surfaces in a continuous culture system and exposed to repeated solution pulses. Galla Chinensis extracts, sucrose solutions, and sodium fluoride solutions were pulsed into different flow cells. The pH value of the planktonic phase in each flow cell was recorded and the bacteria colonizing the biofilm on the HA discs were counted. Enamel blocks were observed using a polarized microscope and lesion depth was evaluated. The biofilm morphology was examined with a fluorescence microscope and the images captured were analyzed on an image analysis system.

Results:  When Galla Chinensis extract, its chemical fraction, or fluoride was added to the sucrose solution, the planktonic phase pH remained higher than that in the sucrose alone. A lower level of colonization on the HA surface was also observed in the groups to which Galla Chinensis and fluoride were added compared with the control sucrose group, and this was reflected in both the total viable count and the biofilm imaging, which showed fewer cariogenic bacteria and a less compact biofilm, respectively. Enamel demineralization in both the fluoride group and the Galla Chinensis group was significantly less than that in the sucrose group.

Conclusions:  Galla Chinensis and fluoride may inhibit the cariogenicity of the oral biofilm. Galla Chinensis appears to be a promising source of new agents that may prevent dental caries.