bluuebunny/crossref_metadata_2025 huggingface dataset:
Monoclonal gammopathy of undetermined significance and smouldering multiple myeloma: emphasis on risk factors for progression
Authors: Kyle Robert A. , Rajkumar S. Vincent
Published: November 2007

Monoclonal gammopathy of undetermined significance (MGUS) is characterized by a serum monoclonal protein <30 g/l, <10% plasma cells in the bone marrow, and absence of end‐organ damage (CRAB–hypercalcaemia, renal insufficiency, anaemia, or bone lesions). MGUS is present in 3% of persons >50 years and in 5% >70 years of age. The risk of progression to multiple myeloma (MM) or a related disorder is 1% per year. Patients with risk factors consisting of an abnormal serum free light chain ratio, non‐immunoglobulin G (IgG) MGUS, and an elevated serum M protein ≥15 g/l had a risk of progression at 20 years of 58%, compared with 37% with two risk factors present, 21% with one risk factor present, and 5% when none of the risk factors were present. Smouldering (asymptomatic) multiple myeloma is characterized by having a serum IgG or IgA monoclonal protein of 30 g/l or higher and/or 10% or more plasma cells in the bone marrow but no evidence of end‐organ damage. The cumulative probability of progression to active MM or amyloidosis was 51% at 5 years, 66% at 10 years and 73% at 15 years; the median time to progression was 4·8 years.
Gene expression and pathway analysis of immune thrombocytopenic purpura
Authors: Sood Ruchira , Wong Wendy , Gotlib Jason , Jeng Michael , Zehnder James L
Published: November 2007

A global expression profile of peripheral blood from patients with immune thrombocytopenic purpura (ITP) was performed that identified an ITP‐specific signature, which also included interferon (IFN)‐induced genes. Several genes correlated with ITP have been shown to be associated with expression signatures in systemic lupus erythematosis and rheumatoid arthritis, indicating an overlap with other autoimmune disorders. Pathway analysis demonstrated that IFN signalling, death receptor and protein ubiquitination pathways were associated with ITP. These results provide the first glimpse of the genes and pathways consistently aberrant in ITP, identifying new targets for investigations of pathogenesis and treatment of ITP.
Photochemically enhanced delivery of a cell‐penetrating peptide nucleic acid conjugate targeting human telomerase reverse transcriptase: effects on telomere status and proliferative potential of human prostate cancer cells
Authors: Folini M. , Bandiera R. , Millo E. , Gandellini P. , Sozzi G. , Gasparini P. , Longoni N. , Binda M. , Daidone M. G. , Berg K. , Zaffaroni N.
Published: November 2007

Abstract.  Objectives: Peptide nucleic acids (PNAs) are DNA mimics that have been demonstrated to be efficient antisense/antigene tools in cell‐free systems. However, their potential as in vivo regulators of gene expression has been hampered by their poor uptake by living cells, and strategies need to be developed for their intracellular delivery. This study has aimed to demonstrate the possibility (i) of efficiently delivering a PNA, which targets mRNA of the catalytic component of human telomerase reverse transcriptase (hTERT), into DU145 prostate cancer cells through a combined approach based on conjugation of the PNA to Tat internalizing peptide (hTERT‐PNA‐Tat) and subsequent photochemical internalization, and (ii) to interfere with telomerase function. Materials and methods: Treated cells were analysed for telomerase activity, hTERT expression, growth rate, ability to undergo apoptosis and telomere status. Results: After exposure to light, DU145 cells treated with hTERT‐PNA‐Tat and the photosensitiser TPPS2a showed dose‐dependent inhibition of telomerase activity, which was accompanied by marked reduction of hTERT protein expression. A dose‐dependent decline in DU145 cell population growth and induction of caspase‐dependent apoptosis were also observed from 48 h after treatment. Such an antiproliferative effect was associated with the presence of telomeric dysfunction, as revealed by cytogenetic analysis, in the absence of telomere shrinkage, and with induction of DNA damage response as suggested by the increased expression of γ‐H2AX. Conclusions: Our results (i) indicate photochemical internalization as an efficient approach for intracellular delivery of chimaeric PNAs, and (ii) corroborate earlier evidence suggesting pro‐survival and anti‐apoptotic roles of hTERT, which are independent of its ability to maintain telomere length.
Functional role of CCCTC binding factor in insulin‐stimulated cell proliferation
Authors: Gao J. , Li T. , Lu L.
Published: November 2007

Abstract.  Objectives: CCCTC binding factor (CTCF) is a nuclear protein containing an 11‐zinc‐finger DNA‐binding domain. CTCF plays important roles in the regulation of epigenetics and gene transcription. As a multifunctional protein, CTCF is also involved in the regulation of cell proliferation and of apoptosis. However, mechanisms underlining the regulatory function of CTCF in mediating growth factor‐ and cytokine‐stimulated cell fate are largely unknown. Materials and Methods: The effect of CTCF on insulin‐induced ML‐1 cell proliferation was investigated by studying insulin‐stimulated extracellular signal‐regulated kinase (Erk) and Akt signalling pathways, and the alterations of CTCF activity in these cells. Results: The present study demonstrates that insulin‐induced human haematopoietic myeloblastic ML‐1 cell proliferation requires increased CTCF expression. Inhibition of Erk and Akt pathways with specific blockers or by dominantly negative expression of Erk and Akt mutants markedly suppressed expression of CTCF and resulted in retardation of cell proliferation. Furthermore, insulin‐induced ML‐1 cell proliferation was significantly enhanced by overexpression of cDNA encoding full‐length CTCF. In contrast, ML‐1 cell proliferation was inhibited by knocking down CTCF mRNA using specific small interference RNA. Conclusions: Our results indicate that CTCF is indeed a protein with multifunctional activity that plays a significant role in modulating signalling pathways to mediate insulin‐induced ML‐1 cell proliferation.
A unified model of sigmoid tumour growth based on cell proliferation and quiescence
Authors: Kozusko F. , Bourdeau M.
Published: November 2007

Abstract.  Objectives: A class of sigmoid functions designated generalized von Bertalanffy, Gompertzian and generalized Logistic has been used to fit tumour growth data. Various models have been proposed to explain the biological significance and foundations of these functions. However, no model has been found to fully explain all three or the relationships between them. Materials and Methods: We propose a simple cancer cell population dynamics model that provides a biological interpretation for these sigmoids’ ability to represent tumour growth. Results and Conclusions: We show that the three sigmoids can be derived from the model and are in fact a single solution subject to the continuous variation of parameters describing the decay of the proliferation fraction and/or cell quiescence. We use the model to generate proliferation fraction profiles for each sigmoid and comment on the significance of the differences relative to cell cycle‐specific and non‐cell cycle‐specific therapies.
Quantification of allochthonous nutrient input into freshwater bodies by herbivorous waterbirds
Authors: HAHN S. , BAUER S. , KLAASSEN M.
Published: November 2007

1. Waterbirds are considered to import large quantities of nutrients to freshwater bodies but quantification of these loadings remains problematic. We developed two general models to calculate such allochthonous nutrient inputs considering food intake, foraging behaviour and digestive performance of waterbirds feeding in terrestrial habitats: an intake model (IM), mainly based on an allometric relationship for energy requirements and a dropping model (DM), based on allometric relationships for defaecation.

2. Reviewed data of nitrogen (N) and phosphorus (P) content of herbivorous food varied according to diet type (foliage, seeds and roots), season and fertilization. For model parameterization average foliage diet contained 38.20 mg N g−1 and 3.21 mg P g−1 (dry weight), whereas mean faeces composition was 45.02 mg N g−1 and 6.18 mg P g−1.

3. Daily allochthonous nutrient input increased with body mass ranging from 0.29 g N and 0.03 g P in teals Anas crecca to 5.69 g N and 0.57 g P in mute swans Cygnus olor. Results from IM differed from those of DM from ducks to swans by 63–108% for N and by −4 to 23% for P. Model uncertainty was lowest for the IM and mainly caused by variation in estimates of food retention time (RT). In DM food RT and dropping mass determined model uncertainty in similar extent.

4. Exemplarily applying the models to Dutch wetlands resulted in mean annual contribution of herbivorous waterbirds to allochthonous nutrient loading of 382.8 ± 167.1 tonnes N a−1and 34.7 ± 2.3 tonnes P a−1, respectively, which corresponds to annual surface‐water loadings of 1.07 kg N ha−1 and 0.10 kg P ha−1.

5. There was a distinct seasonal pattern with peak loadings in January, when bird abundances were highest. Lowest inputs were in August, when bird abundance and nutrient content in food was low and birds foraged less in terrestrial habitats. Three‐quarters of all nutrient input was contributed by greater white‐fronted goose Anser albifrons, greylag goose Anser anser, wigeon Anas penelope and barnacle goose Branta leucopsis alone.

6. We provide general, easy to use calculation methods for the estimation of allochthonous nutrient inputs by waterbirds, which are applicable to a range of waterbird species, a variety of potential diets and feeding behaviours, and across spatial scales. Such tools may greatly assist in the planning and execution of management actions for wetland nutrient budgets.
Indirect effects of a parasite on a benthic community: an experiment with trematodes, snails and periphyton
Authors: BERNOT RANDALL J. , LAMBERTI GARY A.
Published: November 2007

1. Few studies have directly addressed the role played by parasites in the structure and function of ecosystems. Parasites influence the behaviour, reproduction and overall fitness of their hosts, but have been usually overlooked in community and ecosystem‐level studies. We investigated the effects of trematode parasites on snail–periphyton interactions.

2.Physa  acuta(Gastropoda: Pulmonata) snails infected with the trematodePosthodiplostomum minimum(often >30% of within‐shell biomass) grazed more rapidly than uninfected snails. Trematode effects on snail grazing indirectly affected the standing stock and community structure of periphyton. Populations of snails with 50% infected individuals reduced algal biomass by 20% more than populations with lesser (10% or 0%) infection rates.

3. The algaCladophora glomeratadominated periphyton communities grazed by snail populations with 50% infection rates, whereas diatoms and blue–green algal taxa dominated when grazed by snail populations with lower infection rates.

4. Thus, trematodes indirectly affected periphyton communities by altering host snail behaviour, a trait‐mediated indirect effect. These results indicate that trematodes can indirectly influence benthic community structure beyond simple population fitness, with possible related effects on ecosystem function.
Assessment of long‐term changes in habitat availability for Arctic charr (Salvelinus alpinus) in a temperate lake using oxygen profiles and hydroacoustic surveys
Authors: JONES IAN D. , WINFIELD IAN J. , CARSE FIONA
Published: November 2007

1. Hydroacoustics (2002–04) and long‐term oxygen data (1969–2004) have been used in conjunction to examine the habitat of Arctic charr in the north and south basins of Windermere, U.K., a temperate lake subjected to cultural eutrophication and subsequent nutrient management.

2. Since 1969 there has been a gradual decline in the oxygen concentration in the bottom waters of both basins of 0.03–0.04 mg L−1year−1, resulting in up to 43% of the volume of the south basin having an oxygen concentration <5 mg L−1 in the early autumn.

3. Hydroacoustic data indicate that most Arctic charr routinely avoid the upper 10 m of the water column irrespective of temperature, with the implication that an observed gradual warming of the lake has not yet directly impacted upon their habitat.

4. In recent years there has been a behavioural response of the Arctic charr population to migrate vertically to avoid oxygen concentrations <2.3–3.1 mg L−1. Further, the depth of the lower bound of the Arctic charr population is shown to be highly correlated with the deep water oxygen concentration throughout the year prior to autumnal overturn.
Long‐term dynamics and community structure of freshwater gastropods exposed to parasitism and other environmental stressors
Authors: GÉRARD CLAUDIA , CARPENTIER ALEXANDRE , PAILLISSON JEAN‐MARC
Published: November 2007

1. Freshwater communities are subject to various abrupt environmental disturbances and increasing pollution levels in their habitat. According to the nature and the periodicity of disturbances (i.e. punctuated, recurrent or continuous), one may expect different kinds of response of the target gastropod communities.

2. The gastropod community of a French lake has been investigated for 10 years to study its responses to three main environmental disturbances: supra‐seasonal droughts, recurrent proliferations of cyanobacteria and parasitism by trematodes. The relationship between this latter factor, considered as a continuous stressor, and the gastropod community was a particular focus.

3. A total of 13 280 gastropods belonging to 17 species (mostly Pulmonata with Planorbidae as the dominant family) have been sampled in the lake over the 10‐year time series. Species composition of the gastropod community varied strongly during the study period as did species richness (0–14, mean of 6.5 ± 0.4 species) and abundance of gastropods (0–4456, mean of 192 ± 72 individuals). Trematode larvae belonging to 11 morphotypes of cercariae were detected in 15 of the 17 species of gastropods and had a total prevalence of 2.9%.

4. Droughts (punctuated stressor) were responsible for the disappearance of nearly all gastropod species, and thus represent a severe environmental stressor for them. Nevertheless, the extent of this stressor was limited since the gastropod community was highly resilient.

5. Recurrent proliferations of toxic cyanobacteria (recurrent stressor) coincided with the large decline of the gastropod community, corresponding to a strong decrease in abundance and species richness. Intoxication of gastropods by toxic cyanobacteria was demonstrated by the bioaccumulation of microcystins in all gastropod tissues.

6. Trematode parasitism (continuous stressor) did not affect the gastropod community despite the possibly strong impact of parasites on some host species (those with monthly prevalence as high as 100% at some times). Indeed, abundance and species richness of gastropods were scarcely influenced by trematode prevalence or species richness.
Northern map turtles (Graptemys geographica) derive energy from the pelagic pathway through predation on zebra mussels (Dreissena polymorpha)
Authors: BULTÉ GRÉGORY , BLOUIN‐DEMERS GABRIEL
Published: November 2007

1. Zebra mussels (Dreissena polymorpha) derive their energy from the pelagic energy pathway by filtering plankton. Because zebra mussels occur in high densities in littoral habitats, they potentially constitute an important trophic link between littoral consumers and pelagic energy sources. Northern map turtles (Graptemys geographica) are widespread in North America and consume zebra mussels.

2. We used stable isotopes analyses to quantify the flow of energy from the pelagic pathway to northern map turtles and to infer the contribution of zebra mussels to map turtle biomass. We then built a bioenergetic model to estimate the annual intake of zebra mussels by northern map turtles in Lake Opinicon, Ontario, Canada.

3. Stable isotopes analyses indicated that zebra mussels constitute between 0% and 14% of the diet of males and between 4% and 36% of the diet of females. Assuming that zebra mussels account for all of the pelagic contribution, we estimated that map turtles consume 3200 kg of zebra mussels annually. Because female map turtles are much larger than males and consume more zebra mussels, they are responsible for 95% of the zebra mussel biomass ingested annually.

4. The pelagic pathway supports an important part of the standing crop biomass of map turtles in Lake Opinicon. We highlight the importance of freshwater turtles in lake ecosystems. Unravelling the trophic interactions mediated by freshwater turtles will lead to a more integrated picture of lake ecosystems.
Double‐square‐root one‐way wave equation prestack tau migration in heterogeneous media
Authors: Cheng Jiubing , Ma Zaitian , Geng Jianhua , Wang Huazhong
Published: November 2007

In this paper, source‐receiver migration based on the double‐square‐root one‐way wave equation is modified to operate in the two‐way vertical traveltime (τ) domain. This tau migration method includes reasonable treatment for media with lateral inhomogeneity. It is implemented by recursive wavefield extrapolation with a frequency‐wavenumber domain phase shift in a constant background medium, followed by a phase correction in the frequency‐space domain, which accommodates moderate lateral velocity variations. More advanced τ‐domain double‐square‐root wave propagators have been conceptually discussed in this paper for migration in media with stronger lateral velocity variations. To address the problems that the full 3D double‐square‐root equation prestack tau migration could meet in practical applications, we present a method for downward continuing common‐azimuth data, which is based on a stationary‐phase approximation of the full 3D migration operator in the theoretical frame of prestack tau migration of cross‐line constant offset data. Migrations of synthetic data sets show that our tau migration approach has good performance in strong contrast media. The real data example demonstrates that common‐azimuth prestack tau migration has improved the delineation of the geological structures and stratigraphic configurations in a complex fault area.

Prestack tau migration has some inherent robust characteristics usually associated with prestack time migration. It follows a velocity‐independent anti‐aliasing criterion that generally leads to reduction of the computation cost for typical vertical velocity variations. Moreover, this τ‐domain source‐receiver migration method has features that could be of help to speed up the convergence of the velocity estimation.
Prevalence and technical quality of root fillings in Dakar, Senegal
Authors: Touré B. , Kane A. W. , Sarr M. , Ngom C. T. H. , Boucher Y.
Published: November 2007

Aim  To examine the prevalence and technical quality of root fillings and the periapical status of root‐filled teeth in a subpopulation of Dakar, Senegal.

Methodology  Full‐mouth periapical radiographs were obtained from 208 consecutive adults presenting as new patients to the Dental Service of the University. The occurrence and technical quality of root fillings were assessed for each root according to the apical extent of the root fillings and its density. The periapical status was evaluated using the Periapical Index Scoring System with a PAI > 2 indicating periapical disease. The presence of coronal restorations and posts was also noted. Statistical analysis was performed with the chi‐square test with a significance level set at P < 0.05%.

Results  Of the 6234 teeth examined, 2.6% were root filled. A PAI > 2 was associated with 56.1% of the filled roots. Only 17.7% of the root fillings were technically acceptable and 26.2% of these were associated with a PAI > 2. In roots with unacceptable root fillings, 62.5% had a PAI > 2. Unacceptable root fillings were associated with a higher prevalence of periapical disease (P < 0.001). A post was seen in 18.9% of the filled roots with 66.2% associated with a PAI > 2. A permanent coronal restoration was present in 78.5% of the filled roots, of which 50.7% had a PAI > 2 vs 75.7% for no permanent restoration. At least one periapical lesion was seen in 59.6% of the subjects.

Conclusion  The results indicate a low prevalence of teeth with radiographic periapical disease, a low prevalence of root‐filled teeth and a high prevalence of unacceptable root fillings.
Influence of multiple clinical use on fatigue resistance of ProTaper rotary nickel‐titanium instruments
Authors: Vieira E. P. , França E. C. , Martins R. C. , Buono V. T. L. , Bahia M. G. A.
Published: November 2007

Aim  To examine the influence of clinical use on the occurrence of deformation and fracture and on the fatigue resistance of ProTaper rotary instruments.

Methodology  Root canal treatments were performed on patients using the ProTaper rotary system. Ten sets of instruments were used by an experienced endodontist, each set in five molars. Another 10 sets of instruments were used by the same operator, each set in eight molars. In addition, 10 sets of instruments were used, each set in five molars, by undergraduate students with no clinical experience with the system. After clinical use, S1, S2, F1 and F2 instruments were analysed for damage by optical and scanning electron microscopy. The used sets, along with a control group of 12 sets of new instruments, were then tested in a bench device for fatigue resistance.

Results  The use of the ProTaper rotary instruments by an experienced endodontist allowed for the cleaning and shaping of the root canal system of up to eight molars without fracture. During the students work, six instruments fractured. Fatigue resistance decreased upon clinical use for all instruments analysed.

Conclusions  Fatigue resistance of used instruments was reduced, but no significant change was observed amongst the instruments used for shaping the canals of five and eight molars. Operator experience affected the occurrence of fracture and plastic deformation during shaping.
Dental behavioural management problems and dental caries prevalence in 3‐ to 6‐year‐old Swedish children born preterm
Authors: BROGÅRDH‐ROTH SUSANNE , STJERNQVIST KARIN , MATSSON LARS
Published: November 2007

Background.  Today, most children born preterm survive without major impairments. But high frequencies of cognitive and behavioural difficulties arise. Studies on dental behavioural management problems (DBMP) in these children are lacking. In addition, studies on caries prevalence are few and inconclusive.

Aim.  This study aims to compare the frequency of behavioural problems and poor compliance with dental treatment in preschool children born preterm with those born full‐term. The prevalence of caries was also studied.

Methods.  The study group included 187 children born between 23 and 32 weeks of gestation. The control group constituted full‐term children matched by age, sex, immigrant background, and dental operator. DBMP, number of dental visits, missed appointments, and caries between ages 3 and 6 were noted.

Results.  At age 3, but not at age 6, the prevalence of DBMP at clinical examinations was significantly higher in preterm children compared with the control group. Of the children who received dental treatments during preschool years, preterm children displayed significantly more DBMP. No significant difference in dental visits or in caries prevalence was found. Preterm children, however, missed significantly more dental appointments.

Conclusion.  Children born preterm display a higher prevalence of DBMP at dental examinations and treatments during preschool years.
Enhancing staff attitudes, knowledge and skills in supporting the self‐determination of adults with intellectual disability in residential settings in Hong Kong: a pretest–posttest comparison group design
Authors: Wong P. K. S. , Wong D. F. K.
Published: November 2007

Background  The ecological perspective recognizes the critical role that is played by rehabilitation personnel in helping people with intellectual disability (ID) to exercise self‐determination, particularly in residential settings. In Hong Kong, the authors developed the first staff training programme of its kind to strengthen the competence of personnel in this area. The purpose of this study was to examine the effectiveness of staff training in enhancing residential staff's attitudes, knowledge and facilitation skills in assisting residents with ID to exercise self‐determination.

Methods  A pretest–posttest comparison group design was adopted. Thirty‐two participants in an experimental group attended a six‐session staff training programme. A 34‐item self‐constructed scale was designed and used for measuring the effectiveness of the staff training.

Results  The results showed that the experimental group achieved statistically significant positive changes in all domains, whereas no significant changes were found in the comparison group.

Conclusions  The findings provided initial evidence of the effectiveness of staff training that uses an interactional attitude–knowledge–skills model for Chinese rehabilitation personnel. The factors that contributed to its effectiveness were discussed and recommendations for future research were made.
Influence of antibiotic therapy on serum levels of reactive oxygen species in ovariectomized bitches
Authors: MUTINATI M. , SPEDICATO M. , MANCA R. , TRISOLINI C. , MINOIA G. , RIZZO A. , SCIORSCI R. L.
Published: November 2007

This study was conducted on 60 ovariectomized bitches. The objectives were to measure the mean reactive oxygen species (ROS) concentrations before, during and after surgery, and to investigate the effect of the administration of five different antibiotic treatments: amoxicillin, benzylpenicillin/dihydrostreptomycin, sulfametazine/sulfamerazine/sulfathiazole, enrofloxacin, lincomycin/spectinomycin. The first value recorded represented the mean ROS concentration in anestral bitches and constitutes a reference level with which to compare the subsequent measurements. After premedication, induction of anesthesia and during maintenance and surgery, ROS serum concentrations showed constant values until the end of surgery. After surgery and during antibiotic administration, an increase in ROS concentration occurred, which differed among the five groups in relation to the antibiotics employed. The lowest increases occurred in the groups treated with the combination of lincomycin/spectinomycin, and with amoxicillin; whereas the highest increases were detected in the group treated with enrofloxacin. The three other antibiotics showed an intermediate level of influence on oxidative status.
Genetic variation and phylogeography of free‐living mouse species (genusMus) in the Balkans and the Middle East
Authors: MACHOLÁN M. , VYSKOČILOVÁ M. , BONHOMME F. , KRYŠTUFEK B. , ORTH A. , VOHRALÍK V.
Published: November 2007

This work presents a study of the distribution and pattern of variation throughout the ranges of three free‐living mouse species of the genusMus—M. macedonicus,M. spicilegus, and aM. cypriacus— based on sequencing of two segments of the mitochondrial DNA (mtDNA) control region. The study shows a similar level of variability in the three species and suggests their recent population expansion. The highest proportion of variation is found within populations indicating low genetic structuring. Phylogenetic analysis confirms the significant divergence of a mitochondrial lineage ofM. macedonicusfrom Israel, recently described as a new subspecies,M. macedonicus spretoides. Conversely, no genetic hiatus is revealed between European and Asian populations ofM. macedonicus macedonicus. Although phylogenetic relationships amongM. spicileguspopulations could not be unravelled precisely, the results suggest a recent westward expansion of the species. The mtDNA divergence betweenM. macedonicusandM. spicilegusis 7.3%, suggesting their split betweenc.700 000 and 1 million years ago. These dates correspond with a coalescent estimate about 720 000 years ago. On the other hand,M. cypriacusappeared almost twice as divergent from the former species (4.5%) as from the latter (8.8%) suggesting a divergence ofc.430 000–610 000 years ago (coalescent ≈ 490 000 years ago) and 830 000–1.2 million years ago (coalescent ≈ 780 000 years ago), respectively. Approximate times of population expansion have also been estimated for all taxa and groups of populations. Existence of several glacial refuges and various colonization scenarios are discussed; since all estimated divergence times fall within interglacial periods it seems that climatic oscillations did not play a crucial role in the evolution of the three species.
High variation and strong phylogeographic pattern among cpDNA haplotypes in Taxus wallichiana (Taxaceae) in China and North Vietnam
Authors: GAO L. M. , MÖLLER M. , ZHANG X.‐M. , HOLLINGSWORTH M. L. , LIU J. , MILL R. R. , GIBBY M. , LI D.‐Z.
Published: November 2007

We studied the phylogeography of Chinese yew (Taxus wallichiana), a tree species distributed over most of southern China and adjacent regions. A total of 1235 individuals from 50 populations from China and North Vietnam were analysed for chloroplast DNA variation using polymerase chain reaction–restriction fragment length polymorphism of the trnL‐F intron‐spacer region. A total of 19 different haplotypes were distinguished. We found a very high level of population differentiation and a strong phylogeographic pattern, suggesting low levels of recurrent gene flow among populations. Haplotype differentiation was most marked along the boundary between the Sino‐Himalayan and Sino‐Japanese Forest floristic subkingdoms, with only one haplotype being shared among these two subkingdoms. The Malesian and Sino‐Himalayan Forest subkingdoms had five and 10 haplotypes, respectively, while the relatively large Sino‐Japanese Forest subkingdom had only eight. The strong geography–haplotype correlation persisted at the regional floristic level, with most regions possessing a unique set of haplotypes, except for the central China region. Strong landscape effects were observed in the Hengduan and Dabashan mountains, where steep mountains and valleys might have been natural dispersal barriers. The molecular phylogenetic data, together with the geographic distribution of the haplotypes, suggest the existence of several localized refugia during the last glaciation from which the present‐day distribution may be derived. The pattern of haplotype distribution across China and North Vietnam corresponded well with the current taxonomic delineation of the three intraspecific varieties of T. wallichiana.
Mechanical barriers to introgressive hybridization revealed by mitochondrial introgression patterns inOhomopterusground beetle assemblages
Authors: NAGATA NOBUAKI , KUBOTA KOHEI , YAHIRO KATSURO , SOTA TEIJI
Published: November 2007

To reveal the role of diverged body size and genital morphology in reproductive isolation among closely related species, we examined patterns of, and factors limiting, introgressive hybridization between sympatricOhomopterusground beetles in central Japan using mitochondrial NADH dehydrogenase subunit 5 (ND5) gene sequences. We sampled 17 local assemblages that consisted of two to five species and estimated levels of interspecific gene flow using the genetic distance,DA, and maximum‐likelihood estimates of gene flow. Sharing of haplotypes or haplotype lineages was detected between six of seven species that occurred in the study areas, indicating mitochondrial introgression. The intensity and direction of mitochondrial gene flow were variable among species pairs. To determine the factors affecting introgression patterns, we tested the relationships between interspecificDAand five independent variables: difference in body size, difference in genital size, phylogenetic relatedness (nuclear gene sequence divergence), habitat difference, and species richness of the assemblage. Body and genital size differences contributed significantly to preventing gene flow. Thus, mechanical isolation mechanisms reduce the chance of introgressive hybridization between closely related species. Our results highlight the role of morphological divergence in speciation and assemblage formation processes through mechanical isolation.
Loss of synaptophysin and synaptosomal‐associated protein 25‐kDa (SNAP‐25) in elderly Down syndrome individuals
Authors: Downes E. C. , Robson J. , Grailly E. , Abdel‐All Z. , Xuereb J. , Brayne C. , Holland A. , Honer W. G. , Mukaetova‐Ladinska E. B.
Published: November 2007

Aims: This study quantified the density of the synaptic proteins synaptophysin and synaptosomal‐associated protein 25‐kDa (SNAP‐25) in brains from elderly Down's syndrome individuals. Methods: Six areas (frontal, occipital, parietal and temporal lobes, cerebellum and hippocampus) of post mortem brains from elderly Down's syndrome (DS) individuals (with reported functional memory problems and pathologically established Alzheimer's disease) and elderly controls were studied. Results: Collectively in the six brain areas studied, there were significantly lower levels of both synaptophysin and SNAP‐25 immunostaining in the DS group compared with controls. The elderly control group displayed a significant decrease in the densities of synaptophysin and SNAP‐25 as a function of age at death (AAD; P ≤ 0.001), whereas the DS group only showed a significant decrease as a function of AAD for synaptophysin. Assessing synaptic density as a function of Braak stage (BST) revealed a significant decrease in synaptophysin density for both groups. SNAP‐25 was only significantly decreased as a function of BST in the DS group. Synaptic protein density was also shown to vary according to gender. Thus, both DS and control female subjects had a higher synaptic density of SNAP‐25 than their male counterparts. In contrast, male DS and control individuals had a significantly greater density of synaptophysin than females. Conclusions: These results indicate that elderly DS individuals have lower synaptic densities of both analysed proteins than cognitively intact elderly individuals. Although AAD and BST show varying significance to decreases in protein density for both DS and control groups, results suggest that gender differences also play a role in the type of synaptic protein lost in elderly DS individuals.
Increased levels of reactive oxygen species and expression of a cytoplasmic aconitase/iron regulatory protein 1 homolog during the early response of maize pulvini to gravistimulation
Authors: CLORE A. M. , DOORE S. M. , TINNIRELLO S. M. N.
Published: November 2007

The maize (Zea mays L.) stem pulvinus is a disc of tissue located apical to each node that functions to return a tipped stem to a more upright position via increased cell elongation on its lower side. We investigated the possibility that reactive oxygen species (ROS) and hydrogen peroxide (H2O2), in particular, are involved in the gravitropic response of the pulvinus prior to initiation of the growth response by employing the cytochemical stain 3,3′‐diaminobenzidine (DAB). DAB polymers were found in the bundle sheath cells of gravistimulated pulvini in association with amyloplasts after 1 min of gravistimulation, and the signal spread throughout the cytosol of these cells by 30 min. Furthermore, treatment of maize stem explants containing pulvini with 1 mm H2O2 on their upper sides caused reversal of bending polarity. Similar, though less dramatic, results were obtained via application of 1 mm ascorbic acid to the lower side of the explants. In addition, we determined that a maize cytoplasmic aconitase/iron regulatory protein 1 (IRP1) homolog is up‐regulated in the pulvinus bundle sheath cells after gravistimulation using suppressive subtractive hybridization PCR (SSH PCR), real‐time RT‐PCR and in situ hybridization. Although we do not yet know the role of the IRP1 homolog in the pulvinus, the protein is known to be a redox sensor in other systems. Collectively, our results point to an increase in ROS quite early in the gravitropic signalling pathway and its possible role in determining the direction of bending of the pulvini. We speculate that an ROS burst may serve to link the physical phenomenon of amyloplast sedimentation to the changes in cellular biochemistry and gene expression that facilitate directional growth.
Adjuvant Effects of Bacillus Calmette–Guerin DNA or CpG‐oligonucleotide in the Immune Response to Taenia solium Cysticercosis Vaccine in Porcine
Authors: Guo Y.‐J. , Wu D. , Wang K.‐Y. , Sun S.‐H.
Published: November 2007

The immune stimulation properties of CpG‐oligonucleotides (CpG‐ODN) containing a central unmethylated CpG motif could be useful for vaccination against parasite infection. However, the high cost of synthetic CpG‐ODN has limited its use in veterinary vaccines. In this study, we investigated whether genomic DNA derived from Mycobacterium bovis bacillus Calmette–Guerin (BCG‐DNA) could be used as an effective adjuvant to enhance the immunogenicity and the protective capacity of recombinant cC1 antigen (rcC1) against pig cysticercosis. Pigs were vaccinated with rcC1 plus CpG‐containing DNA adjuvants (BCG‐DNA or CpG‐ODN) or rcC1 alone. Immunization with rcC1 alone induced a Th1‐biased response, whereas coadministration of rcC1 with BCG‐DNA or CpG‐ODN increased levels of IgG2, IFN‐γ, percentage of CD8+ and specific proliferation of peripheral blood mononuclear cells. Four weeks after the last immunization, pigs were infected with Taenia solium eggs. A high level of protection (81%) was induced by rcC1 immunization that was not significantly increased by the CpG‐containing DNA. These data indicate that coadministration of rcC1 plus BCG‐DNA or CpG‐ODN significantly enhanced Th1 response but did not improve the level of the protection induced.
Regulatory CD4+CD25+ T Cells Prevent Thymic Dysfunction in Experimental Chronic Colitis
Authors: Veltkamp C. , Ruhwald R. , Veltkamp R. , Giese T. , Stremmel W.
Published: November 2007

Chronic colitis in T‐cell deficient Tgε26 mice develops due to a dysfunction of the thymus which generates colitogenic T cells after bone marrow (BM) transplantation. Regulatory CD4+CD25+ T cells have been shown to prevent colitis in this model by normalizing the peripheral T‐cell pool. We tested the hypothesis that T‐cell normalization takes place in the thymus. Tgε26 mice were transplanted with BM (BM→Tgε26 mice) and consequently received either CD4+CD25+ or CD4+CD25− cells from syngenic wild type mice. Furthermore, untransplanted Tgε26 mice received CD4+CD25+ or CD4+CD25− cells or complete mesenteric lymph node cells. Transfer of regulatory. CD4+CD25+ cells normalized the total number of thymocytes and the percentage and number of double positive CD4+CD8+ cells in transplanted mice while percentage of single positive CD4+ and CD8+ thymocytes in BM→Tgε26 mice was reduced upon CD4+CD25+ transfer. Timing of CD4+CD25+ cell injection was important as transfer later than 7 days after BM transplantation failed to prevent abnormal thymic T‐cell distribution in BM→Tgε26 mice. Isolated CD4+CD25+ cell transfer without preceding BM transplantation failed to reconstitute thymic architecture. Differences of thymic cell composition could not be exclusively explained by presence or absence of colitis, respectively, because 19 days after BM transplantation when both groups showed no histological signs of colitis, animals transferred with CD4+CD25+ T cells had a significantly higher percentage and number of CD4+CD25+ thymocytes and CD4+Foxp3+ cells than BM→Tgε26 mice. In conclusion, early CD4+CD25+ cotransfer prevents thymic dysfunction which underlies immune‐mediated bowel inflammation in BM→Tgε26 mice.
TNF‐α is Secreted by Monocytes in Transit to become Macrophages, but not by Peripheral Blood Monocytes, following OK‐432 (Lyophilized S. pyogenes) Stimulation
Authors: Olsnes C. , Stavang H. , Olofsson J. , Aarstad H. J.
Published: November 2007

OK‐432, penicillin‐killed Streptococcus pyogenes, is used in treating lymphangiomas and carcinomas. We have studied proinflammatory interleukin (IL) secretion following OK‐432 stimulation of total blood, peripheral blood mononuclear cell (PBMC) and purified monocytes in vitro. OK‐432 stimulation of purified monocytes gave IL‐1β, IL‐1RA, IL‐6, IL‐12p40 and tumour necrosis factor (TNF)‐α response. OK‐432 stimulation of cells within blood did, however, not yield TNF‐α secretion. When PBMC or monocytes were cultured in low‐attachment wells a decreased IL secretion was observed compared to adherent cells. Inhibition of Syk kinase with piceatannol, only at high, non‐specific doses, but not PI3 kinase inhibition with LY294002 or Wortmannin, decreased monocyte IL response to OK‐432. This shows that β1–3‐integrin receptor function is not necessary for monocyte OK‐432‐stimulated TNF‐α secretion. Direct blockage of the β2‐integrin (CD18) receptor by anti‐CD18 antibody was also unable to prevent the stimulating effects of OK‐432 in human monocytes. On the other hand, Syk phosphorylation is elevated upon adherence of monocytes and this is further increased by OK‐432 stimulation, as shown by Western blot. The Fc‐receptor was also ruled out as a main receptor of the OK‐432 monocyte response. In conclusion, TNF‐α secretion is only found in monocytes removed from blood. This TNF‐α secretion is not mediated through the β1–3‐integrin receptors. OK‐432 may act as a target‐seeking substance whereby only monocytes adhered, e.g. to a tumour cell, become cytotoxic in part explaining why OK‐432 is well suited as a cancer treatment drug.
Intentional Pathogen Killing – or Denial of Substrate?
Authors: Cunliffe J.
Published: November 2007

For years, the accepted view in immunology has been that a core function of the immune system is to identify and eliminate invading micro‐organisms (generally referred to as ‘pathogens’). Metaphorically, the system locates, chases, attacks, kills, disposes of and eliminates ‘pathogens’. This is encapsulated in the phrase ‘intentional pathogen killing’. This purpose has remained, more or less, unchallenged until the 1990s but its authority is now becoming suspect. In a series of published articles, I have suggested that the core function of the immune (or morphostatic) system is to dispose of tissue debris (mess/non‐mess discrimination) and restore order. The debris of degenerating cells provides a rich source of nutrients for micro‐organisms. Could it be that the major goal of the immune system is to rapidly dispose of such debris? This strategy could lead to a ‘denial‐of‐nutrient‐substrate’ that starves invading bacteria out of contention and, in consequence, suppresses infection. This perspective can be adapted to encompass the patho‐physiology of other infective organisms. While this perspective sits well with the morphostasis model, it could also be applied to other models.
Naïve Donor Responses to Schistosoma mansoni Soluble Egg Antigens
Authors: Reis E. A. G. , Azevedo T. M. , McBride A. J. A. , Harn D. A. , Reis M. G.
Published: November 2007

Schistosome infection induces profound Th‐biasing and immune suppression. Although much has been examined in mice, few studies have examined responses of naïve humans to schistosome antigens. In this study, we examined the response of naïve human peripheral blood mononuclear cells (nPBMC) to stimulation with Schistosoma mansoni soluble egg antigen (SEA) using a priming in vitro (PIV) assay. We found that SEA induced a pronounced CD4+ T‐helper cell response based on cytokine secretion and phenotyping markers. SEA‐stimulated nPBMC (SEA cells) at day 7 post‐priming and after the first recall consisted predominantly of Th0‐like CD4+ T cells. Following the second recall, the majority of donor (10/12) responses were Th2‐like. The cell population consisted of approximately 64% CD4+, 17% CD8+high, 12% CD19+, and 7% CD23+ cells. The CD4+ population also expressed HLA‐DR+, CD54+, CD45RO+ and CD25+ whereas the CD19+ cells expressed CD80 and CD86. Following priming, we detected high levels of IL‐6, IFN‐γ, IL‐12p40, IL‐10 and IL‐5. Upon restimulation, SEA cells secreted IL‐5 and high levels of IL‐10, typical of a Th2‐like response. The data presented herein shows that the majority of naïve donor dendritic cells, following stimulation with SEA, prime and clonally expand SEA‐specific T cells towards a Th2‐type response. However, two donors responded with an atypical response, producing IFN‐γ coincident with low levels of IL‐10. Whether this differential response was due to HLA or other genes was not determined but is currently under investigation.
A rapid, whole‐tissue determination of the functional fraction of PSII after photoinhibition of leaves based on flash‐induced P700 redox kinetics
Authors: Losciale Pasquale , Oguchi Riichi , Hendrickson Luke , Hope Alexander B. , Corelli‐Grappadelli Luca , Chow Wah Soon
Published: November 2007

Assaying the number of functional PSII complexes by the oxygen yield from leaf tissue per saturating, single‐turnover flash, assuming that each functional PSII evolves one oxygen molecule after four flashes, is one of the most direct methods but time‐consuming. The ratio of variable to maximum Chl fluorescence yield (Fv/Fm) in leaves can be correlated with the oxygen yield per flash during a progressive loss of PSII activity associated with high‐light stress and is rapid and non‐intrusive, but suffers from being representative of chloroplasts near the measured leaf surface; consequently, the exact correlation depends on the internal leaf structure and on which leaf surface is being measured. Our results show that the average Fv/Fm of the adaxial and abaxial surfaces has a reasonable linear correlation with the oxygen yield per flash after varied extents of photoinactivation of PSII. However, we obtained an even better linear correlation between (1) the integrated, transient electron flow (Σ) to P700+, the dimeric Chl cation in PSI, after superimposing a single‐turnover flash on steady background far‐red light and (2) the relative oxygen yield per flash. Leaves of C3 and C4 plants, woody and herbaceous species, wild‐type and a Chl‐b‐less mutant, and monocot and dicot plants gave a single straight line, which seems to be a universal relation for predicting the relative oxygen yield per flash from Σ. Measurement of Σ is non‐intrusive, representative of the whole leaf tissue, rapid and applicable to attached leaves; it may even be applicable in the field.
A single mitochondrial haplotype and nuclear genetic differentiation in sympatric colour morphs of a riverine cichlid fish
Authors: KOBLMÜLLER S. , SEFC K. M. , DUFTNER N. , KATONGO C. , TOMLJANOVIC T. , STURMBAUER C.
Published: November 2007

Some of the diversity of lacustrine cichlid fishes has been ascribed to sympatric divergence, whereas diversification in rivers is generally driven by vicariance and geographic isolation. In the riverine Pseudocrenilabrus philander species complex, several morphologically highly distinct populations are restricted to particular river systems, sinkholes and springs in southern Africa. One of these populations consists of a prevalent yellow morph in sympatry with a less frequent blue morph, and no individuals bear intermediate phenotypes. Genetic variation in microsatellites and AFLP markers was very low in both morphs and one single mtDNA haplotype was fixed in all samples, indicating a very young evolutionary age and small effective population size. Nevertheless, the nuclear markers detected low but significant differentiation between the two morphs. The data suggest recent and perhaps sympatric divergence in the riverine habitat.