bluuebunny/crossref_metadata_2025 huggingface dataset:
Serial studies of methylation of CDKN2B and CDKN2A in relapsed acute promyelocytic leukaemia treated with arsenic trioxide
Authors: Au Wing‐Yan , Fung Alvin T. , Ma Edmond S. , Chan Cheuk‐Hung , Wong Kit‐Fai , Chim Chor‐Sang , Liang Raymond H. , Kwong Yok‐Lam
Published: October 2005

Ninety consecutive patients with acute promyelocytic leukaemia were investigated for promoter methylation of CDKN2B (alias p15) and CDKN2A (alias p16) in disease relapse and progression. CDKN2B methylation was significantly more frequent at first relapse (30/36, 83%) than at presentation (48/77, 62%) (P = 0·025), while CDKN2A methylation appeared unaffected. Both acquisition and loss of CDKN2B methylation happened at relapse, with acquisition more frequent. No significant increase in CDKN2B and CDKN2A methylation occurred at more advanced relapses. At first or subsequent relapses, owing to highly effective salvage by arsenic trioxide, CDKN2B methylation did not impact on event‐free survival or overall survival.
A form of circulating interleukin-6 receptor component soluble gp130 as a potential interleukin-6 inhibitor in inflammatory bowel disease
Authors: Mitsuyama K , Tomiyasu N , Suzuki A , Takaki K , Takedatsu H , Masuda J , Yamasaki H , Matsumoto S , Tsuruta O , Toyonaga A , Sata M
Published: October 2005

The presence and the role of soluble gp130, the soluble form of a component of the interleukin (IL)-6 receptor complex, were investigated in inflammatory bowel disease. The serum concentrations of soluble gp130 were increased in ulcerative colitis (active disease, median, 93·5 ng/ml; interquartile range, 26–125 ng/ml; inactive disease, 81 ng/ml, 24·8–137·3 ng/ml) and to a lesser extent in Crohn’s disease (active disease, 66 ng/ml, 44·4–87·6 ng/ml; inactive disease, 63 ng/ml, 43·5–82·5 ng/ml) compared to normal controls (43 ng/ml, 27–59 ng/ml). Paired analysis of serum samples showed a decrease of IL-6 and soluble IL-6 receptor concentrations in both diseases and an increase of soluble gp130 concentrations, especially in ulcerative colitis, just after the resolution of disease exacerbation. Size fractionation of the serum revealed that a part of the IL-6 co-eluted with soluble gp130 and soluble IL-6 receptor. The IL-6-induced proliferation of murine B9 hybridoma was enhanced by recombinant soluble IL-6 receptor, whereas the proliferation was inhibited by recombinant soluble gp130. These results indicate that soluble gp130 may function as a natural inhibitor of the IL-6 actions in inflammatory bowel disease.
Oral administration of a new soluble branched β-1,3-D-glucan is well tolerated and can lead to increased salivary concentrations of immunoglobulin A in healthy volunteers
Authors: Lehne G , Haneberg B , Gaustad P , Johansen P W , Preus H , Abrahamsen T G
Published: October 2005

The soluble branched yeast β-1,3-D-glucan (SBG) belongs to a group of carbohydrate polymers known to exert potent immunomodulatory effects when administered to animals and humans. A new oral solution of SBG has been developed for local application to the oropharyngeal and oesophageal mucosa in order to strengthen the defence mechanisms against microbial and toxic influences. In the present study oral administration of SBG has been investigated primarily for assessment of safety and tolerability in an early phase human pharmacological study (phase I). Eighteen healthy volunteers were included among non-smoking individuals. The study was an open 1 : 1 : 1 dose-escalation safety study consisting of a screening visit, an administration period of 4 days and a follow-up period. Groups of six individuals received SBG 100 mg/day, 200 mg/day or 400 mg/day, respectively, for 4 consecutive days. The dose increase was allowed after a careful review of the safety data of the lower dose group. No drug-related adverse event, including abnormalities in vital signs, was observed. By inspection of the oral cavity only minor mucosal lesions not related to the study medication were seen in seven subjects. Repeated measurements of β-glucan in serum revealed no systemic absorption of the agent following the oral doses of SBG. In saliva, the immunoglobulin A concentration increased significantly for the highest SBG dose employed. SBG was thus safe and well tolerated by healthy volunteers, when given orally once daily for 4 consecutive days at doses up to 400 mg.
Effects of phosphorus enrichment and grazing snails on modern stromatolitic microbial communities
Authors: ELSER James J. , SCHAMPEL JOHN H. , GARCIA‐PICHEL FERRAN , WADE BRIAN D. , SOUZA VALERIA , EGUIARTE LUIS , ESCALANTE ANA , FARMER JACK D.
Published: October 2005

1. The effects of phosphorus enrichment and grazing snails on a benthic microbial community that builds stromatolic oncolites were examined in an experiment at Rio Mesquites, Cuatro Ciénegas, Mexico. Chemical analyses of stream water samples indicated that overall atomic ratios of total nitrogen (N) to total phosphorus (P) were approximately 110, indicating a strong potential for P‐limitation of microbial growth.

2. Phosphorus enrichment involved addition of 5 μmol Na2HPO4 L−1 to streamside microcosms receiving intermittent inputs of stream water while grazer manipulation involved removal of the dominant grazer, the snail Mexithauma quadripaludium. After 7 weeks, we examined responses in organic matter content, C : N : P ratios, metabolism (P removal, primary production, dark respiration, and calcification), and microbial community structure using molecular fingerprinting of 16S rRNA genes.

3. Manipulation of snails did not affect response variables measured in these treatments (organic matter, C : P ratio, P removal rate). However, P enrichment significantly decreased the C : P and N : P ratios of surficial materials in the oncolites (organic matter content was unchanged), increased net and gross photosynthesis (oxygen consumption in the dark was unchanged), increased rates of calcification, and increased diatoms relative to cyanobacteria. Heterotrophic Eubacteria and Archaea were only modestly affected. Thus, our results indicate weak grazing effects but strong impacts of P in this benthic system.

4. We hypothesise that a state of severe P‐limitation is imposed on autotrophic production in this food web due, at least in part, to co‐precipitation of phosphate during calcite deposition. This produces severe P‐limitation of the benthic algae and cyanobacteria, resulting in high C : P ratio of microbial mats relative to the biomass of photoautotrophs (phytoplankton, terrestrial foliage) in other ecosystems. In turn, this high C : P ratio is likely to generate severe stoichiometric constraints on the herbivores, thus limiting their populations and resulting in weak overall grazing impacts.
Response of grazing snails to phosphorus enrichment of modern stromatolitic microbial communities
Authors: ELSER JAMES J. , SCHAMPEL JOHN H. , KYLE MARCIA , WATTS JAMES , CARSON EVAN W. , DOWLING THOMAS E. , TANG CAROL , ROOPNARINE PETER D.
Published: October 2005

1. The effects of added phosphorus (P) on the growth, P and RNA : DNA contents, and survivorship of snails grazing on laminated microbial mats (living ‘stromatolites’) were examined in the Rio Mesquites at Cuatro Ciénegas, Mexico (total P, c. 0.60 μmol L−1) to test the hypothesis that strong P‐limitation of microautotroph growth produces a stoichiometric constraint on herbivores because of mineral P‐limitation.

2. In a 3‐week experiment performed in summer 2001, addition of phosphorus (+15 μmol L−1) resulted in a strong decline in stromatolite biomass C : P ratio from very high levels (c. 2300 : 1 by atoms) to moderate levels (c. 550 : 1). The endemic hydrobiid snail Mexithauma quadripaludium responded to P‐enrichment with elevated body P content and higher RNA : DNA ratios, especially for small animals likely to be actively growing. This positive response is consistent with the existence of a stoichiometric constraint on snail growth.

3. In a longer experiment (8 weeks) involving a more moderate P enrichment (+5 μmol L−1) in summer 2002, P enrichment reduced stromatolite C : P ratio from moderate values in control treatments (c. 750) to very low values (<100 : 1). Snails responded to stromatolite P‐enrichment with increased body P content but, in contrast to the first experiment, with lower RNA : DNA ratio, lower growth rates, and higher mortality.

4. These contrasting results suggest that both very high and very low biomass C : P ratios in stromatolites are detrimental to M. quadripaludium performance, leading us to hypothesise that these herbivores live on a ‘stoichiometric knife edge’.
CD45: all is not yet crystal clear
Authors: Holmes Nick
Published: October 2005

CD45 has been recognized as an important player in regulating signalling in lymphocytes. However, compared with tyrosine kinases, phosphatases are still poorly understood in terms of the details of their specificity and regulation. Here, the recent progress in understanding the biology of the first recognized receptor tyrosine phosphatase, CD45, is reviewed.
A realist study of the mechanisms of cardiac rehabilitation
Authors: Clark Alexander M , Whelan Heather K , Barbour Rosaline , MacIntyre Paul D
Published: October 2005

Aim.  The aim of this paper is to report patients’ experiences of cardiac rehabilitation and perceptions of the mechanisms and contexts influencing its long‐term effectiveness.

Background.  Cardiac rehabilitation programmes for the secondary prevention of coronary heart disease are common. The effects of these programmes, however, can be inconsistent and little is known of the personal and contextual factors that influence service effectiveness.

Method.  Forty‐seven participants with a formal diagnosis of coronary heart disease who had attended a programme of cardiac rehabilitation in Scotland 3 years previously were included in focus groups to discuss their perceptions and experiences (30 males and 17 females). The data were generated in 2002 and analysed using the realist approach of Pawson and Tilley (1997).

Results.  Participants’ accounts indicated that the didactic content of cardiac rehabilitation was not strongly linked to longer‐term health behaviour change. The main positive effects of cardiac rehabilitation were related to the effect of participation on mediating social and body‐focused mechanisms that were triggered when the rehabilitation setting was perceived to be safe. Social mechanisms identified included social comparisons, camaraderie, and social capital. Body‐focused mechanisms included greater knowledge of personal physical boundaries and a greater trust in the heart‐diseased body. Collectively, these mechanisms had a positive effect on confidence that was perceived as being imperative to maintain health behaviour change.

Conclusions.  More support is required to promote health behaviour change after the completion of cardiac rehabilitation. Use of community‐based exercise services and conventional or web‐based support groups for coronary heart disease patients should be encouraged, as these appear to extend the positive health effects of the mechanisms that promote behaviour change. At the completion of cardiac rehabilitation programmes, patients should be referred to safe and appropriate community‐based exercise services. Further research is needed to examine the effects on health outcomes of mechanisms and contexts related to cardiac rehabilitation.
Introducing older people to the theory of gerotranscendence
Authors: Wadensten Barbro
Published: October 2005

Aim. This paper reports a study whose aims were to introduce the theory of gerotranscendence to a group of older people; to give participants in the group an opportunity to discuss their ageing process; to study how participants described their ageing in relation to the theory; and to gather participants’ opinions about discussing their ageing in a group.

Background. The theory of gerotranscendence states that human development is a process extending into old age. Guidelines had previously been derived for its practical use in the care of older people, aiming to promote their development towards gerotranscendence.

Methods. A qualitative descriptive approach was taken, and older people were invited to participate in group sessions at a day centre. At the sessions, participants discussed their ageing, and a video presentation about the theory of gerotranscendence was shown at one of the sessions. They were encouraged to discuss the description of the ageing process presented in the video and to link this to their own experiences of growing old. The discussion in each session was tape‐recorded and transcribed verbatim. Data were analysed and categorized using qualitative methods. The data were collected in 2002.

Findings. All women had an experience of ageing that was in some way in line with the theory's description, and they more or less agreed that this description of ageing was in accordance with their own ageing. They considered that it was interesting and fruitful to discuss ageing in a group. They felt that introduction of the view of ageing offered by the theory of gerotranscendence was beneficial because it gave them a more positive view of ageing which also allowed them to be as they were.

Conclusion. It is possible to arrange this type of group activity for older people, resulting in possibilities to use aspects of the theory of gerotranscendence as an intervention in gerontological nursing.
Evaluation of an action research project in ophthalmic nursing practice
Authors: Waterman Heather , Harker Rona , MacDonald Heather , McLaughlan Rita , Waterman Christine
Published: October 2005

Aim.  This paper reports the evaluation phase of an action research project that promoted face‐down posturing of patients following vitreo‐retinal surgery for macular hole to enhance patient outcomes. The evaluation phase identified areas of practice needing further development from the perspectives of those involved with the care of patients.

Background.  To achieve best results following surgical repair of macular hole, patients are required to posture face down for several weeks. As a consequence, patients complain of severe back and neck ache and find it difficult to persist with the posturing. Work to advance nursing practice as surgical developments occur has relevance beyond ophthalmology and the particular context of this project.

Method.  The first three phases of this action research – problem identification, planning and action – have been reported in another paper. Throughout the project an action research group comprising of representatives of key stakeholders were actively involved in researching and changing practice. During the evaluation phase, a qualitative methodology was chosen. Interviews with 17 members of staff from the inpatient area were carried out to elicit their perspectives on the posturing of patients. Qualitative interviews were selected to facilitate comparison with interview data from Phase 1. Data analysis ran concurrently with data collection, so that one could inform the other.

Findings.  Overall, nurses and healthcare support workers felt that patients were more agreeable to posturing and after surgery began to posture more quickly. Communication was still an issue in some instances, and patients having urgent as opposed to planned surgery were found to be more difficult to prepare and the psychological care of patients still posed problems for nursing staff.

Conclusions.  The evaluation suggests that improvements in the care of this group of patients have occurred. A 10‐point plan to promote face‐down posturing has been developed which will be of use to practitioners in other settings. Some aspects of practice remain less well‐understood, for example, the psychological care of patients.
Lizard habitat partitioning on islands: the interaction of local and landscape scales
Authors: Buckley Lauren B. , Roughgarden Joan
Published: October 2005

Aim This study addresses how species resolve environmental differences into biological habitats at multiple, interacting spatial scales. How do patterns of local habitat use change along an elevation gradient? How do patterns of local habitat partitioning interact with partitioning at a landscape scale?

Location Northern and southern Lesser Antilles islands, West Indies.

Methods We document howAnolisDaudin, 1802 lizards partition habitat locally at sites along a landscape‐scale elevation gradient. We examine habitat partitioning both with and without interspecific interactions in the predominately flat northern Lesser Antilles islands and in the more mountainous southern islands.

Results Anoles partition local habitat along perch‐height and microclimate axes. Northern‐group sympatric anoles partition local habitat by perch height and have overlapping distributions at the landscape scale. Southern‐group sympatric anoles partition local habitat by microclimate and specialize in particular habitats at the landscape scale. In both the northern and southern groups, species use different perch heights and microclimates only in areas of species overlap along the elevation gradient.

Main conclusions We demonstrate the interaction between local‐ and landscape‐scale habitat partitioning. In the case of microclimate partitioning, the interaction results from the use of thermal physiology to partition habitat at multiple scales. This interaction prompts the question of whether habitat partitioning developed ‘local‐out’ or ‘landscape‐in’. We pose this dichotomy and present a framework for its resolution.
The relative importance of local, regional and historical factors determining the distribution of plants in fragmented riverine forests: an emergent group approach
Authors: Hérault Bruno , Honnay Olivier
Published: October 2005

Aim To investigate how local, regional and historical factors shape the herbaceous plant communities in fragmented riverine forests, and how the community composition and species richness of these fragments is related to the interplay between the environmental factors and specific plant life‐trait combinations.

Location Riverine forest fragments in the Grand‐duché de Luxembourg.

Methods Forest fragments were surveyed for their abundance in herbaceous plant species. All plant species where clustered into Emergent Groups (EG) by means of a formal classification based on 14 life‐history traits. Within each EG, the local, regional and historical factors were related to the community composition using partial Canonical Correspondence Analyses (pCCA) and to the species richness using Generalized Linear Models (GLMs). The EG colonization ability was characterized by means of logistic regressions.

Results We defined and characterized seven EGs, among which three consisted of forest specialist species (barochorous perennials, short geophytes and zoochorous perennials), which exhibited specific life‐trait combinations: large and short‐lived seeds and/or vernal phenology. Differences in EG composition between forest fragments were mainly explained by local environmental factors such as soil productivity and pH. The richness of barochorous perennials and short geophytes was well predicted by the historical and regional factors. The colonization ability appeared very low for barochorous perennials and short geophytes.

Main conclusions Local environmental conditions appear to drive the differentiation of the riverine forest plant communities owing to the specific habitat requirements of many forest species. Spatial and temporal forest discontinuities affect the richness of forest specialist species, due to dispersal and/or recruitment limitations. The emergent group approach enhances the understanding of the relative influence of local, regional and historical factors by distinguishing between forest specialists from generalists or ‘matrix’ species, which have a masking effect.
Input data, analytical methods and biogeography of Elegia (Restionaceae)
Authors: Moline P. M. , Linder H. P.
Published: October 2005

Aim  The aim of this paper is to determine the optimal methods for delimiting areas of endemism for Elegia L. (Restionaceae), an endemic genus of the Cape Floristic Region. We assess two methods of scoring the data (presence–absence in regular grids, or in irregular eco‐geographical regions) and three methods for locating biogeographical centres or areas of endemism, and evaluate one method for locating biotic elements.

Location  The Cape Floristic Region (CFR), South Africa.

Methods  The distribution of all 48 species of Elegia was mapped as presence–absence data on a quarter‐degree grid and on broad habitat units (eco‐geographical areas). Three methods to delimit areas of endemism were applied: parsimony analysis of endemism (PAE), phenetic cluster analysis, and NDM (‘endemism’). In addition, we used presence–absence clustering (‘Prabclus’) to delimit biotic elements. The performances of these methods in elucidating the geographical patterns in Elegia were compared, for both types of input data, by evaluating their efficacy in maximizing the proportion of endemics and the number of areas of endemism.

Results  Eco‐geographical areas perform better than quarter‐degree grids. The eco‐geographical areas are potentially more likely to track the distribution of species. The phenetic approach performed best in terms of its ability to delimit areas of endemism in the study area. The species richness and the richness of range‐restricted species are each highest in the south‐western part of the CFR, decreasing to the north and east. The phytogeographical centres identified in the present study are the northern mountains, the southern mountains (inclusive of the Riviersonderend Mountains and the Cape Peninsula), the Langeberg range, the south coast, the Cape flats, and the west coast.

Main conclusions  This study demonstrates that (1) eco‐geographical areas should be preferred over a grid overlay in the study of biogeographical patterns, (2) phenetic clustering is the most suitable analytical method for finding areas of endemism, and (3) delimiting biotic elements does not contribute to an understanding of the biogeographical pattern in Elegia. The areas of endemism in Elegia are largely similar to those described in other studies, but there are many detailed differences.
Serum γ‐glutamyltransferase and risk of type 2 diabetes mellitus in men and women from the general population
Authors: MEISINGER C. , LÖWEL H. , HEIER M. , SCHNEIDER A. , THORAND B. ,   FOR THE KORA STUDY GROUP
Published: October 2005

Objectives.  To examine gender‐specific associations between γ‐glutamyltransferase (GGT) and incident type 2 diabetes mellitus in a representative population‐based sample in Germany.

Design.  Prospective population‐based study.

Methods.  The study was based on 1851 men and 1836 women (aged 25–64 years) who participated in the first Monitoring Trends and Determinants on Cardiovascular Diseases (MONICA) Augsburg Survey 1984/1985, and who were free of diabetes at baseline. Incident cases of type 2 diabetes were assessed using follow‐up questionnaires in 1987/1988, 1997/1998 and 2002/2003 and were validated with medical records. Gender‐specific hazard ratios (HRs) were estimated from Cox proportional hazard models.

Results.  A total of 172 cases of incident type 2 diabetes amongst men and 109 amongst women were registered during a mean follow‐up period of 14.7 years. In both sexes the risk of type 2 diabetes increased with increasing levels of serum GGT. After multivariable adjustment HRs for incident type 2 diabetes across GGT categories (<25th, <50th, <75th, <87.5th and ≥87.5th percentiles) were 1.0, 1.81, 2.37, 3.41 and 4.24 (P‐value for trend <0.0001) in men and 1.0, 1.42, 1.48, 1.95 and 2.41 (P‐value for trend 0.0179) in women. Obesity appeared to be more strongly associated with type 2 diabetes in women with GGT equal or greater than the median compared to women with GGT below the median. However, in men the association between obesity and type 2 diabetes was almost identical in the two groups.

Conclusions.  The GGT is an important predictor for incident type 2 diabetes in men and women from the general population.
Unbiased estimation of relative reproductive success of different groups: evaluation and correction of bias caused by parentage assignment errors
Authors: ARAKI HITOSHI , BLOUIN MICHAEL S.
Published: October 2005

Parentage assignment is widely applied to studies on mating systems, population dynamics and natural selection. However, little is known about the consequence of assignment errors, especially when some parents are not sampled. We investigated the effects of two types of error in parentage assignment, failing to assign a true parent (type A) and assigning an untrue parent (type B), on an estimate of the relative reproductive success (RRS) of two groups of parents. Employing a mathematical approach, we found that (i) when all parents are sampled, minimizing either type A or type B error insures the minimum bias on RRS, and (ii) when a large number of parents is not sampled, type B error substantially biases the estimated RRS towards one. Interestingly, however, (iii) when all parents were sampled and both error rates were moderately high, type A error biased the estimated RRS even more than type B error. We propose new methods to obtain an unbiased estimate of RRS and the number of offspring whose parents are not sampled (zWz), by correcting the error effects. Applying them to genotypic data from steelhead trout (Oncorhynchus mykiss), we illustrated how to estimate and control the assignment errors. In the data, we observed up to a 30% assignment error and a strong trade‐off between the two types of error, depending on the stringency of the assignment decision criterion. We show that our methods can efficiently estimate an unbiased RRS and zWz regardless of assignment method, and how to maximize the statistical power to detect a difference in reproductive success between groups.
Tempo and mode of speciation in the Baja California disjunct fish species Anisotremus davidsonii
Authors: BERNARDI GIACOMO , LAPE JENNIFER
Published: October 2005

The Baja California region provides a natural setting for studying the early mechanisms of allopatric speciation in marine systems. Disjunct fish populations from several species that occur in the northern Gulf of California and northern Pacific coast of Baja California, but are absent from its southern shores, were previously shown to be genetically isolated, making them excellent candidates for studying allopatry. In addition, one of these species, the sargo Anisotremus davidsonii, has two pairs of congeneric Panamic trans‐isthmian geminate species that allow for internal molecular clock calibration. Phylogeographic and demographic approaches based on mitochondrial (cytochrome b) and nuclear (S7 ribosomal protein) sequences showed that A. davidsonii entered the gulf from the south, and later colonized the Pacific coast, approximately 0.6–0.16 million years ago. Pacific coast colonization may have used a route either around the southern cape of Baja California or across the peninsula through a natural seaway. However, while several seaways have been described from different geological times, none matches the dates of population disjunction, yet much geological work remains to be done in that area. At the present time, there is no evidence for dispersal around the southern tip of the Baja California Peninsula. Signatures of incipient allopatric speciation were observed, such as the reciprocal monophyly of disjunct populations for the mitochondrial marker. However, other characteristics were lacking, such as a strong difference in divergence and coalescence times. Taken together, these results suggest that disjunct populations of A. davidsonii may be consistent with the earliest stages of allopatric speciation.
Population genetic analysis identifies source–sink dynamics for two sympatric garter snake species (Thamnophis elegans and Thamnophis sirtalis)
Authors: MANIER MOLLIE K. , ARNOLD STEVAN J.
Published: October 2005

Population genetic structure can be shaped by multiple ecological and evolutionary factors, but the genetic consequences of these factors for multiple species inhabiting the same environment remain unexplored. We used microsatellite markers to examine the population structures of two coexisting species of garter snake, Thamnophis elegans and Thamnophis sirtalis, to determine if shared landscape and biology imposed similar population genetic structures. These snakes inhabit a series of ponds, lakes and flooded meadows in northern California and tend to converge on prey type wherever they coexist. Both garter snakes had comparable effective population sizes and bidirectional migration rates (estimated using a maximum‐likelihood method based on the coalescent) with low but significant levels of genetic differentiation (FST = 0.024 for T. elegans and 0.035 for T. sirtalis). Asymmetrical gene flow revealed large source populations for both species as well as potential sinks, suggesting frequent extinction–recolonization and metapopulation dynamics. In addition, we found a significant correlation between their genetic structures based on both pairwise FSTs for shared populations (P = 0.009) and for bidirectional migration rates (P = 0.024). Possible ecological and evolutionary factors influencing similarities and differences in genetic structure for the two species are discussed. Genetic measures of effective population size and migration rates obtained in this study are also compared with estimates obtained from mark–recapture data.
The polysaccharide capsule of the pathogenic fungus Cryptococcus neoformans enlarges by distal growth and is rearranged during budding
Authors: Zaragoza Oscar , Telzak Andrew , Bryan Ruth A. , Dadachova Ekaterina , Casadevall Arturo
Published: October 2005

The capsule of Cryptococcus neoformans can undergo dramatic enlargement, a phenomenon associated with virulence. A prior study that used Ab to the capsule as a marker for older capsular material concluded that capsule growth involved the intermixing of new and old capsular material with displacement of older capsular polysaccharide towards the surface. Here we have revisited that question using complement (C), which binds to capsular polysaccharide covalently, and cannot redistribute by dissociation and binding at different sites. The experimental approach involved binding of C to cells with small capsules, inducing capsule growth, and following the location of C relative to the cell wall as the capsule enlarged. C remained close to the cell wall during capsule growth, indicating that capsule enlargement occurred by addition of new polysaccharide near the capsule edge. This conclusion was confirmed by an independent method that employed radioactive metabolic labelling of newly synthesized capsule with 3H‐mannose followed by gradual capsular stripping with γ‐radiation. Capsule growth proceeded to a certain size, which was a function of cell size, and was not degraded when the cells were transferred to a non‐inducing medium. During budding, an opening appeared in the capsule of the mother cell that permitted the nascent bud to separate. Scanning EM suggested that a physical separation formed between the capsules of the mother and daughter cells during budding, which may avoid mixture between both capsules. Our results indicate that C. neoformans capsular enlargement also occurs by apical growth and that budding results in capsular rearrangements.
P1 plasmid partition: in vivo evidence for the ParA‐ and ParB‐mediated formation of an anchored parS complex in the absence of a partner parS
Authors: Edgar Rotem , Biek Donald , Yarmolinsky Michael
Published: October 2005

ParA and ParB proteins and cis‐acting site, parS, are required to partition plasmid P1 faithfully to daughter cells. The process may initiate from plasmids paired by ParB at which recruited ParA then acts to effect the separation. We previously reported evidence for ParB‐mediated pairing of parS sites on plasmids in the absence of ParA. In DNA gyrase‐inhibited cells, the pairing prevented diffusion of transcription‐generated positive supercoils. This supercoil trapping was almost entirely in plasmid dimers, where the location of the parS sites in cis facilitated their pairing. Here we show that the addition of ParA blocked supercoil diffusion also in plasmid monomers. The possibility that this result is attributed to an enhancement by ParA of ParB‐mediated pairing in trans is consistent with our finding that ParA appeared to partially suppress the pairing defect of two mutant ParB proteins. However, enhanced pairing alone could not account for the diffusion barrier in plasmid monomers; it was manifest in monomers even when they were largely devoid of partners in the same cell. Apparently, ParA altered the ParB–parS complex such that it could no longer swivel, most likely by anchoring it, a reaction of probable relevance to partition.
Porphyromonas gingivalis‐induced platelet aggregation in plasma depends on Hgp44 adhesin but not Rgp proteinase
Authors: Naito Mariko , Sakai Eiko , Shi Yixin , Ideguchi Hiroshi , Shoji Mikio , Ohara Naoya , Yamamoto Kenji , Nakayama Koji
Published: October 2005

Evidence from recent epidemiological studies suggests a link between periodontal infections and increased risk of atherosclerosis and related cardiovascular and cerebrovascular events in human subjects. One of the major pathogens of periodontitis, Porphyromonas gingivalis, has the ability to aggregate human platelets in platelet‐rich plasma (PRP). Mechanism of P. gingivalis‐induced platelet aggregation in PRP was investigated. Proteinase inhibitors toward Arg‐gingipain (Rgp) and Lys‐gingipain (Kgp) did not suppress P. gingivalis‐induced platelet aggregation in PRP, whereas the Rgp inhibitor markedly inhibited P. gingivalis‐induced platelet aggregation using  washed  platelets.  Mutant  analysis  revealed  that P. gingivalis‐induced platelet aggregation in PRP depended on Rgp‐, Kgp‐ and haemagglutinin A (HagA)‐encoding genes that intragenically coded for adhesins such as Hgp44. Hgp44 adhesin on the bacterial cell surface, which was processed by Rgp and Kgp proteinases, was essential for P. gingivalis‐induced platelet aggregation in PRP. P. gingivalis cell‐reactive IgG in plasma, and FcγRIIa receptor and to a lesser extent GPIbα receptor on platelets were found to be a prerequisite for P. gingivalis‐induced platelet aggregation in PRP. These results reveal a novel mechanism of platelet aggregation by P. gingivalis.
Cytopathic changes and pro‐inflammatory cytokines induced by Naegleria fowleri trophozoites in rat microglial cells and protective effects of an anti‐Nfa1 antibody
Authors: OH Y.‐H. , JEONG S.‐R. , KIM J.‐H. , SONG K.‐J. , KIM K. , PARK S. , SOHN S. , SHIN H.‐J.
Published: October 2005

Naegleria fowleri, a free‐living amoeba, causes fatal primary amoebic meningoencephalitis in experimental animals and humans. The nfa1 gene (360 bp) was previously cloned from a cDNA library of pathogenic N. fowleri by immunoscreening, and produced a 13·1‐kDa recombinant protein that showed pseudopodia‐specific localization by immunocytochemistry. On the basis of an idea that the pseudopodia‐specific Nfa1 protein seems to be involved in the pathogenicity of N. fowleri, the cytopathic activity of N. fowleri trophozoites co‐cultured with rat microglial cells was observed, and the effects of an anti‐Nfa1 antibody in a co‐culture system were elucidated. Using light, scanning and transmission electron microscopy, it was seen that N. fowleri trophozoites in contact with microglial cells produced vigorous pseudopodia and a food‐cup structure. Microglial cells were destroyed by N. fowleri trophozoites as seen from necrotic cell death in a time‐dependent manner. In a51Cr release assay, N. fowleri showed 17·8%, 24·9%, 54·6% and 98% cytotoxicity against microglial cells at 3, 6, 12 and 24 h post‐incubation, respectively. However, when anti‐Nfa1 antibody was added in a coculture system, N. fowleri cytotoxicity was reduced to 15·5%, 20·3%, 46·7% and 66·9%, respectively. Moreover, microglial cells co‐cultured with N. fowleri trophozoites secreted the pro‐inflammatory cytokines, TNF‐α, IL‐1β and IL‐6. In the presence of anti‐Nfa1 antibody, the secretion of TNF‐α was slightly, but not significantly, decreased.
The stimulating effects of ethylene and auxin on petiole elongation and on hyponastic curvature are independent processes in submerged Rumex palustris
Authors: COX MARJOLEIN C. H. , PEETERS ANTON J. M. , VOESENEK LAURENTIUS A. C. J.
Published: October 2005

The flooding‐tolerant plant species Rumex palustris (Sm.) responds to complete submergence with stimulation of petiole elongation mediated by the gaseous hormone ethylene. We examined the involvement of auxin in petiole elongation. The manipulation of petiolar auxin levels by removing the leaf blade, or by addition of synthetic auxins or auxin transport inhibitors, led to the finding that auxin plays an important role in submergence‐induced petiole elongation in R. palustris. A detailed kinetic analysis revealed a transient effect of removing the auxin source (leaf blade), explaining why earlier studies in which less frequent measurements were taken failed to identify any role for auxin in petiole elongation. We previously showed that the onset of stimulated petiole elongation depends on a more upright petiole angle being reached by means of hyponastic (upward) curvature, a differential growth process that is also regulated by ethylene and auxin. This raised the possibility that both ethylene and auxin stimulate elongation only indirectly by influencing hyponastic growth. We show here that the action of ethylene and auxin in promoting petiole elongation in submerged R. palustris is independent of the promoting effect that these hormones also exert on the hyponastic curvature of the same petiole.
NMR metabolite profiling analysis reveals changes in phospholipid metabolism associated with the re‐establishment of desiccation tolerance upon osmotic stress in germinated radicles of cucumber
Authors: AVELANGE‐MACHEREL M.‐H. , LY‐VU B. , DELAUNAY J. , RICHOMME P. , LEPRINCE O.
Published: October 2005

The adaptation of metabolism is thought to play a role in the acquisition of desiccation tolerance (DT). However, the importance of such a role and whether specific regulatory pathways exist remain to be assessed. Using in vitro31P and 13C nuclear magnetic resonance (NMR) spectroscopy and biochemical assays, we analysed metabolite profiles of perchloric extracts from germinating radicles of cucumber to identify changes in carbon and phosphate metabolism associated with DT. Emerged radicles measuring 2 mm long can be rendered tolerant to desiccation by incubation in a polyethylene glycol (PEG) solution with a water potential of −1.5 MPa. However, in 4‐mm‐long emerged radicles, this treatment was ineffective. This manipulable system enabled the discrimination of changes in metabolites associated with DT from those associated with the response to osmotic stress. Independent of radicle length, the PEG treatment resulted in an increase in sucrose (Suc) content, whereas glucose (Glc), fructose (Fru) and the hexose phosphate pool, as well as phosphoenolpyruvate decreased three‐ to fourfold. In addition, three derivatives arising early during phospholipid catabolism (glycerylphosphorylcholine, glycerylphosphorylethanolamine and glycerylphosphorylinositol) appeared in the PEG‐treated radicles. Interestingly, phospholipid degradation was much more pronounced in osmotically challenged radicles that remain sensitive to drying. This was proved by the appearance of catabolites, such as phosphocholine and phosphoethanolamine, solely in 4 mm PEG‐treated radicles. Furthermore, glycerol‐3‐phosphate and its derivative 3‐phosphoglycerate increased significantly. Our data suggest that the metabolic response leading to the re‐establishment of DT is not entirely identical to that of an osmotic response. It is inferred that membrane remodelling and/or increased phospholipid catabolism is an adaptive response common to osmotic adjustment and DT but is controlled differently in tolerant and sensitive radicles.
Reduced levels of volatile emissions in jasmonate‐deficientspr2tomato mutants favour oviposition by insect herbivores
Authors: SÁNCHEZ‐HERNÁNDEZ CARLA , LÓPEZ MERCEDES G. , DÉLANO‐FRIER JOHN P.
Published: October 2005

Tomato plants release volatile organic compounds (VOCs) following insect or mechanical damage. In this study, the constitutive and wound‐induced emission levels of VOCs in suppressor of prosystemin‐mediated responses2 (spr2) mutant plants, compromised in linolenic acid (LA) and jasmonic acid (JA) synthesis, and in 35S::prosystemin (35S::prosys) plants, having upregulated direct defence responses, were compared. Thespr2mutants produced constitutively lower levels of VOCs, which were nonetheless increased in response to (a)biotic damage, although at lower levels than wild‐type (Wt) and35S::prosysplants. No significant differences in VOC emissions were detected between the latter two genotypes, thereby suggesting that systemin does not regulate indirect defence responses, whereas differences in fatty acid composition inspr2plants led to the predominant emission of saturated C6 volatiles in response to wounding. The expression of 1‐deoxy‐d‐xylulose 5‐phosphate synthase (DXS2), a key gene involved in VOC synthesis in the chloroplast, was only upregulated inManduca sextaL.‐damaged Wt and35S::prosysplants. However, its expression was restored inspr2plants by exogenous LA or JA, suggesting that abated VOC emissions inspr2plants are correlated with loweredDXS2expression. Bioassays with two different insects showed that adult females significantly preferredspr2plants, indicating that lowered levels of VOCs in tomato influence plant selection by insects during oviposition.
Relationship of measles vaccination with anaemia and malaria in western Kenya
Authors: Desai Meghna R. , Holtz Timothy H. , Helfand Rita , Terlouw Dianne J. , Wannemuehler Kathleen A. , Kariuki Simon K. , Shi Ya Ping , Nahlen Bernard L. , Ter Kuile Feiko O.
Published: October 2005

Objective  Mild viral illness, including that following immunization with live attenuated measles virus (LAMV), has been associated with transient decreases in haemoglobin (Hb) and cellular immune response that may persist for several weeks. In areas of intense malaria transmission, such as western Kenya, infants experience a progressive drop in Hb until age 9–10 months and one‐third may have Hb < 8 g/dl. These children may be at risk of developing severe anaemia with further haematological insult. The objective of this paper was to determine if immunization with LAMV was associated with increased risk of transient anaemia and malaria infection.

Methods  Data from previous cross‐sectional surveys (n = 5970) and one cohort study (n = 546) conducted among pre‐school children were analyzed retrospectively.

Results  Measles vaccination coverage between 12 and 23 months of age ranged from 44.8% to 62.7%. Hb concentrations in children aged 6–23 months with documented measles immunization within the previous 14 or 30 days (n = 103) were similar to those with no history of measles immunization in the previous 90 days (n = 996); mean differences [95% confidence interval (CI)] by 30 days were: in cross‐sectional surveys, −0.49 g/dl (−1.12, 0.14); in the cohort study, −0.032 g/dl (−0.52, 0.46). Similarly, the risk of malaria parasitemia or severe to moderate anaemia did not differ.

Conclusion  These data do not suggest that the transient decrease in Hb and cellular immune response after immunization with LAMV results in clinically significant changes in the risk of subsequent severe to moderate anaemia or malaria in young children living in malaria‐endemic regions.
Bipolaris keratomycosis
Authors: Saha Rumpa , Das Shukla
Published: October 2005

A case of mycotic keratitis caused by Bipolaris spicifera is reported. The corneal ulcer developed after 1 week of treatment with corticosteroids and antibiotics. Septate, branched, dematiaceous hyphal elements were detected in the corneal scrapings on two occasions and repeated cultures were positive for this fungus. The infection was resolved with natamycin and itraconazole although the corneal opacity remained and the patient is now waiting for a keratoplasty.
Superficial mycoses due to Trichophyton violaceum in Athens, Greece: a 15‐year retrospective study
Authors: Frangoulis E. , Papadogeorgakis H. , Athanasopoulou B. , Katsambas A.
Published: October 2005

This is a retrospective study on the superficial mycoses due to Trichophyton violaceum in the greater Athens area for the last 15 years – 1989–2003. During this period 104 patients were found to have an infection due to T. violaceum– an incidence rate of 0.75% of all dermatophytosis. Of the patients 59 were Greeks, 15 Greek Gypsies and 30 immigrants mostly from Albania (50%). Of them 58 were children, 46 adults (mainly women, 34 cases). Trichophyton violaceum infection was presented with a variety of manifestations (127 cases). The prevailing was tinea capitis present in 85 patients – 57 children, 24 women and four men (women : men 6 : 1). Tinea capitis together with other forms of the infection was found in 14 patients. Tinea facie, corporis, manuum, barbae and unguium were seen in nineteen patients. The isolation rate of T. violaceum infection in the Greek population remained at a low level for three decades after the mid‐1960s. However, a substantial increase in the isolation rate is observed in the mid‐1990s attributed mainly to the influx of economic immigrants from countries where the infection is endemic.
Expression of double‐stranded RNA‐activated protein kinase in small‐size peripheral adenocarcinoma of the lung
Authors: Roh Mee Sook , Kwak Ju Young , Kim Su Jin , Lee Hyun Wook , Kwon Hyuk Chan , Hwang Tae Ho , Choi Phil Jo , Hong Young Seoub
Published: October 2005

The authors investigated the protein expression of double‐stranded RNA‐activated protein kinase (PKR), which was identified by using a previous cDNA microarray study, to discover PKR's correlations with several pathological parameters and to elucidate its role in neoplastic transformation and progression of lung adenocarcinomas. Immunohistochemistry for PKR was performed and a semiquantitative scoring method was calculated based on staining intensity and percentage of immunoreactive tumor cells (high vs low) for one bronchioloalveolar carcinoma (BAC), 16 adenocarcinomas consisting of BAC and invasive carcinoma (mixed) and 21 invasive adenocarcinomas without BAC (invasive). The BAC had high‐grade expression and the mixed type tended to more frequently show high‐grade expression than the invasive type (P = 0.028). There were no significant associations with age, tumor size, lymph node metastasis, lymphovascular invasion or the pathological stage. The Kaplan–Meier survival curves demonstrated that the patients with high‐grade PKR expression had significantly shorter survival periods than those patients with low‐grade PKR expression (P = 0.018). These results do not support the concept of PKR as a tumor suppressor in small‐size peripheral adenocarcinomas of the lung.