bluuebunny/crossref_metadata_2025_split huggingface dataset:
Signal transduction involved in the platelet adenylate cyclase sensitization associated with PGH2/TxA2 receptor desensitization
Authors: Elalamy Ismail , Emadi Sharareh , Boris Vargaftig B. , Hatmi Mohamed 
Published: November 2003

The exposure of human platelets to prostaglandin H2 analogue (PGH2, U46619) induces homologous desensitization and a concomitant adenylate cyclase (AC) sensitization.We demonstrate the involvement of phospholipase C (PLC) in this enzyme sensitization. Pre‐incubation of platelets with neomycin, a PLC activity inhibitor, prevented AC sensitization but not PGH2/thromboxane (Tx)A2 receptor desensitization. PGH2/TxA2 receptor desensitization, although necessary, is not sufficient to induce AC sensitization, since neomycin, which prevents AC sensitization, failed to prevent receptor desensitization. Inositol phosphate formation, determined in parallel, was also inhibited. Interestingly, no guanylate cyclase sensitization was noted, suggesting a specific relationship between PGH2/TxA2 receptor desensitization and AC sensitization. In addition, using alkaline phosphatase, a dephosphorylating enzyme, and the tyrosine kinase inhibitor erbstatin, we examined the role of phosphorylation–dephosphorylation on AC sensitization. Effectively, alkaline phosphatase, which has no effect by itself, enhances the cAMP production triggered by prostacyclin in control but not in desensitized platelets. In contrast, erbstatin failed to modify this synthesis, indicating the non‐involvement of tyrosine kinase pathway in this process.Our results indicate that the AC sensitization was mediated by PLC and also suggest the participation of other mechanisms, including phosphorylation–dephosphorylation processes. This specific enzyme sensitization may be relevant for the in vivo modulation of platelet activation, in different thrombotic diseases with an increased TxA2 generation.
Restoration of genetic diversity in the dry forest treeSwietenia macrophylla(Meliaceae) after pasture abandonment in Costa Rica
Authors: Céspedes M. , Gutierrez M. V. , Holbrook N. M. , J. Rocha O. 
Published: November 2003

AbstractWe studied the levels of genetic diversity ofSwietenia macrophylla(big leaf mahogany) in five successional plots in the Santa Rosa National Park, Guanacaste, Costa Rica. We selected sites with different lengths of time since the last major disturbance (typically fire): 6, 9, 15 and 20 years. In addition, we also included a patch of mature forest that had experienced selective logging and other human activity in the past 100 years. Genetic diversity was assessed using five polymorphic DNA microsatellite loci. We found a total of 21 alleles in the five loci examined, in which the number of alleles present varied among the five sites studied. Allelic diversity varied between sites ranging from 20 to 14 alleles, and our data revealed that earlier successional sites have more alleles than older sites. There was significant heterogeneity in allele frequencies between sites; however, genetic differentiation between populations was low (FST = 0.063) indicating that most of the variation was found within sites and extensive gene flow between sites. In addition, our analysis also showed that genetic diversity of adult trees does not solely determine the diversity of seedlings and saplings found around them, also supporting the existence of extensive gene flow. The impact of these findings for the design of conservation strategies for tropical dry forests trees is discussed.
Geographic and habitat partitioning of genetically distinct zooxanthellae (Symbiodinium) in Acropora corals on the Great Barrier Reef
Authors: Ulstrup K. E. , Van Oppen M. J. H. 
Published: November 2003

AbstractIntra‐ and intercolony diversity and distribution of zooxanthellae in acroporid corals is largely uncharted. In this study, two molecular methods were applied to determine the distribution of zooxanthellae in the branching corals Acropora tenuis and A. valida at several reef locations in the central section of the Great Barrier Reef. Sun‐exposed and shaded parts of all colonies were examined. Single‐stranded conformational polymorphism analysis showed that individual colonies of A. tenuis at two locations harbour two strains of Symbiodinium belonging to clade C (C1 and C2), whereas conspecific colonies at two other reefs harboured a single zooxanthella strain. A. valida was found to simultaneously harbour strains belonging to two distinct phylogenetic clades (C and D) at all locations sampled. A novel method with improved sensitivity (quantitative polymerase chain reaction using Taqman™ fluorogenic probes) was used to map the relative abundance distribution of the two zooxanthella clades. At two of the five sampling locations both coral species were collected. At these two locations, composition of the zooxanthella communities showed the same pattern in both coral species, i.e. correlation with ambient light in Pioneer Bay and an absence thereof in Nelly Bay. The results show that the distribution of genetically distinct zooxanthellae is correlated with light regime and possibly temperature in some (but not all) colonies of A. tenuis and A. valida and at some reef locations, which we interpret as acclimation to local environmental conditions.
Long‐term population isolation in the endangered tropical tree species Caesalpinia echinata Lam. revealed by chloroplast microsatellites
Authors: Lira C. F. , Cardoso S. R. S. , Ferreira P. C. G. , Cardoso M. A. , Provan J. 
Published: November 2003

AbstractHabitat fragmentation represents the single most serious threat to the survival of tropical ecosystems. In formulating strategies to counteract the detrimental effects of fragmentation, knowledge of the levels and patterns of genetic diversity within and between natural populations is vital to the establishment of any conservation programme. We utilized polymorphic chloroplast microsatellite markers to analyse genetic diversity in populations of the endangered tropical tree Caesalpinia echinata Lam. representing the entire extant range of the species. Levels of within‐population diversity were low, with only two of seven populations studied displaying any variation. The vast majority of the genetic variation was partitioned between geographical regions (36%) and between populations within regions (55%). These levels of genetic structuring, coupled with a calculated pollen‐to‐seed flow ratio of ≈ 6.7:1, suggest that there has been little gene flow between the three major geographical regions over an extended period. Thus, the current tripartite distribution of the species is more consistent with the existence of separate glacial refugia, rather than reflecting any anthropogenic effects.
Selection‐induced variation at the pantophysin locus (PanI) in a Norwegian fjord population of cod (Gadus morhuaL.)
Authors: Karlsson S. , Mork J. 
Published: November 2003

AbstractA total of 1290 cod (Gadus morhuaL.), sampled between 1985 and 1999 from a spawning area in the Trondheimsfjord, Norway, were assayed for the nuclear‐encoded locusPanI(pantophysin). The majority of samples were taken during the spawning season at two nearby sampling locations at depths of 100 and 60 m, respectively. Genetic analysis revealed significant effects of cohort, sex and sampling location on allele frequencies atPanI. The contribution of each of these three factors to the total among‐sample diversity (FST) of 8.01% atPanI was estimated to be 3.78, 2.55 and 1.68%, respectively. Sign tests revealed a significant excess of heterozygotes at both sampling locations in females; a significant excess of heterozygotes in males was observed at one of the localities. Mutation, genetic drift and immigration do not appear to contribute significantly to the observed genetic heterogeneity atPanI, leaving natural selection as the main explanatory factor for the Hardy–Weinberg imbalance. The dynamics of the selection atPanI appear to be complex. Analysis of age, sex and cohort proved crucial to disentangle putative explanatory factors from their secondary effects.
Phylogeography of the fungal pathogenHistoplasma capsulatum
Authors: Kasuga Takao , White Thomas J. , Koenig Gina , Mcewen Juan , Restrepo Angela , Castañeda Elizabetha , Da Silva Lacaz Carlos , Heins‐Vaccari Elisabeth M. , De Freitas Roseli S. , Zancopé‐Oliveira Rosely M. , Qin Zhenyu , Negroni Ricardo , Carter Deidre A. , Mikami Yuzuru , Tamura Miki , Taylor María Lucía , Miller Georgina F. , Poonwan Natteewan , Taylor John W. 
Published: November 2003

AbstractUntil recently,Histoplasma capsulatumwas believed to harbour three varieties, var.capsulatum(chiefly a New World human pathogen), var.duboisii(an African human pathogen) and var.farciminosum(an Old World horse pathogen), which varied in clinical manifestations and geographical distribution. We analysed the phylogenetic relationships of 137 individuals representing the three varieties from six continents using DNA sequence variation in four independent protein‐coding genes. At least eight clades were idengified: (i) North American class 1 clade; (ii) North American class 2 clade; (iii) Latin American group A clade; (iv) Latin American group B clade; (v) Australian clade; (vi) Netherlands (Indonesian?) clade; (vii) Eurasian clade and (viii) African clade. Seven of eight clades represented genetically isolated groups that may be recognized as phylogenetic species. The sole exception was the Eurasian clade which originated from within the Latin American group A clade. The phylogenetic relationships among the clades made a star phylogeny.Histoplasma capsulatumvar.capsulatumindividuals were found in all eight clades. The African clade included all of theH. capsulatumvar.duboisiiindividuals as well as individuals of the other two varieties. The 13 individuals of var.farciminosumwere distributed among three phylogenetic species. These findings suggest that the three varieties ofHistoplasmaare phylogenetically meaningless. Instead we have to recognize the existence of genetically distinct geographical populations or phylogenetic species. Combining DNA substitution rates of protein‐coding genes with the phylogeny suggests that the radiation ofHistoplasmastarted between 3 and 13 million years ago in Latin America.
Genetic consequences of white‐tailed deer (Odocoileus virginianus) restoration in Mississippi
Authors: Deyoung Randy W. , Demarais Stephen , Honeycutt Rodney L. , Rooney Alejandro P. , Gonzales Robert A. , Gee Kenneth L. 
Published: November 2003

AbstractWhite‐tailed deer (Odocoileus virginianus) were nearly extirpated from the southeastern USA during the late 19th and early 20th centuries. Recovery programmes, including protection of remnant native stocks and transplants from other parts of the species’ range, were initiated in the early 1900s. The recovery programmes were highly successful and deer are presently numerous and continuously distributed throughout the southeastern USA. However, the impact of the recovery programmes on the present genetic structure of white‐tailed deer remains to be thoroughly investigated. We used 17 microsatellite DNA loci to assess genetic differentiation and diversity for 543 white‐tailed deer representing 16 populations in Mississippi and three extra‐state reference populations. There was significant genetic differentiation among all populations and the majority of genetic variation (≥ 93%) was contained within populations. Patterns of genetic structure, genetic similarity and isolation by distance within Mississippi were not concordant with geographical proximity of populations or subspecies delineations. We detected evidence of past genetic bottlenecks in nine of the 19 populations examined. However, despite experiencing genetic bottlenecks or founder events, allelic diversity and heterozygosity were uniformly high in all populations. These exceeded reported values for other cervid species that experienced similar population declines within the past century. The recovery programme was successful in that deer were restored to their former range while maintaining high and uniform genetic variability. Our results seem to confirm the importance of rapid population expansion and habitat continuity in retaining genetic variation in restored populations. However, the use of diverse transplant stocks and the varied demographic histories of populations resulted in fine‐scale genetic structuring.
Nonconcordant evolutionary history of maternal and paternal lineages in Adriatic sturgeon
Authors: Ludwig A. , Congiu L. , Pitra C. , Fickel J. , Gessner J. , Fontana F. , Patarnello T. , Zane L. 
Published: November 2003

AbstractAlthough analyses of intraspecific variability are an important prerequisite for species identification assays, only a few studies have focused on population genetics and historical biogeography of sturgeon species. Here we present the first study on genetic variability of the last remaining Adriatic sturgeon, Acipenser naccarii, derived from mitochondrial and nuclear DNA. Our mitochondrial DNA analyses arranged individuals into three distinguished mitochondrial DNA haplogroups (Po1, Po2 and Buna). Two haplogroups (Po1 and Buna) were correlated to geographical distribution, whereas the third (Po2) was not. It was, however, very closely related to one lineage of its Ponto‐Caspian sister species, A. gueldenstaedtii. The distribution of nuclear markers (microsatellites and amplified fragment length polymorphism) was strongly correlated to geographical distribution. An assignment test based on nuclear data placed no specimen of A. naccarii to A. gueldenstaedtii and vice versa. Therefore, the presence of gueldenstaedtii‐like haplotypes within the Po population is either the result of a postglacial introgression or an ancestral polymorphism and does not indicate a hybrid population. The most valuable tool for forensic species identification purposes is one diagnostic deletion separating all A. naccarii from A. gueldenstaedtii. As both A. naccarii populations are genetically differentiated, stocking of sturgeon from the Po River in Italy into waters of the Buna River would jeopardize the genetic differences between both populations and should thus be avoided.
Genetic variation and founder effects in the parasitoid wasp,Diaeretiella rapae(M’intosh) (Hymenoptera: Braconidae: Aphidiidae), affecting its potential as a biological control agent
Authors: Baker D. A. , Loxdale H. D. , Edwards O. R. 
Published: November 2003

AbstractThe effects of recent colonization on the aphid parasitoid,Diaeretiella rapae(M’Intosh) (Hymenoptera: Braconidae: Aphidiidae), in Western Australia were investigated. When compared with populations from the Old World, the results of a microsatellite analysis show that the insects have low allelic length and low allele frequency variation, revealing that these individuals experienced a significant founder effect. Marked genetic differentiation between populations was also revealed, which has potentially important implications for host utilization in this species when introduced to a new geographical area(s). Low genetic variation and gene flow in a founder population could limit evolutionary potential in Australia, including the ability of a population to mount a response to newly introduced hosts, such as the Russian wheat aphid,Diuraphis noxia(Mordvilko). Although the actual importance of genetic diversity in the success of biological control agents is unclear, current theory concerning the potential impact of genetic bottlenecks on additive genetic variance is discussed.
Effects of Colletotrichum gloeosporioides f. sp. malvae on plant development and blomass of non‐target field crops under controlled and field conditions
Authors: MORTENSEN K. , MAKOWSKI R. M. D. 
Published: November 2003

SummaryAs part of the registration requirements for bioherbicides in Canada. Colletorihum gloeosporioides (Pen.) Penz., and Sace. f. sp. malvae (C. g. malvae). a naturally occurring pathogen on Malva pusilla Sm. (round‐leaved mallow), was tested under controlled conditions for its effect and disease developmeiu on ten non‐target crops: oilseed rape, flax, entil, mustard, saf‐flower. sugar beel sunflower, wheat, okra and cotton. All crops except okra and cotton were also tested in the field at Regina and Indian Head. Saskatchewan, When applied at 12 times the recommended field rate (120 × 106 spores m‐2), this fungus was shown to have no adverse etfect on yield or plant development under controlled or field conditions on any of the crops or crop cultivars tested, except in safflower Safflower was susceptible under controlled conditions and under field conditions the cuttivar 'S‐208’showed significantly lower biomass in treated vs. untreated plots in one of threer growing seasons. Therefore, this fungus is not recommended for use in safflower, but can be safely used as a bioherbicide in the other crops tested under field coitditions. C. g. malvae was registered as the first bioherbicide in Canada in 1992.
Persistence of imazamethabenz‐methyl in soils after autumn and spring applications to wheat
Authors: JENSEN K. I. N. , GAUL S. O. , KIMBALL E. R. , SPECHT E. G. 
Published: November 2003

SummaryImazathabenz‐methyl dissipated rapidly in sandy and sandy loam field soils in Nova Scotia. Canada, seeded to wheat (Triticum aestivam L.).The time to 50% loss of herbicide residues in the 0‐10 cm soil zone was about 3‐4 weeks after October applications and about 2.5 weeks after June ones. After October applications, there was further loss of >60% of the remaining parent herbicide during the winter and early spring despite periods of prolonged snow cover and freezing, or near freezing, soil temperatures. After October applications, imazamethabenz‐methyl residues in May‐collected samples from the 10‐20 and 20‐30 cm soil zones ranged from 40% to 80% and from 15% to 40%, respectively of those extracted from the 0‐10 cm zone over four sites. Precipitation in the month after October applications ranged from 105 to 180 mm. which suggests leaching may play an important role in dissipation at times of the year when precipitation greatly exceeds evapotranspiration. Levels of the phytoioxic free acid ranged from 15% to 35% of the parent herbicide in selected samples. These residues had no effect on spring wheat replacement crops. The effect of the herbicide on replacement crops may also be influenced by the soil pH. A laboratory study demonstrated that as soil pH increased from 4.1 to 6.5. degradation of imazamethabenz‐methyl increased with a corresponding increase in free acid formation.
Nurses resisting information technology
Authors: Timmons Stephen 
Published: November 2003

TIMMONS S.Nursing Inquiry2003;10: 257–269Nurses resisting information technologyResistance in the workplace, by nurses, has not been extensively studied from a sociological perspective. In this paper, nurses’ resistance to the implementation and use of computer systems is described and analysed, on the basis of semistructured interviews with 31 nurses in three UK NHS hospitals. While the resistance was not ‘successful’, in that it did not prevent the implementation of the systems, it nonetheless persisted. Resistance took a wide variety of forms, including attempts to minimise or ‘put off’ use of the systems, and extensive criticism of the systems, though outright refusal to use them was very rare. Resistance was as much about the ideas and ways of working that the systems embodied as it was about the actual technology being used. The patterns of resistance can best be summed up by the phrase ‘resistive compliance’.
Rational choice(s)? Rethinking decision‐making on breast cancer risk and screening mammography
Authors: Vahabi Mandana , Gastaldo Denise 
Published: November 2003

VAHABI M. and GASTALDO D. Nursing Inquiry 2003; 10: 245–256 Rational choice(s)? Rethinking decision‐making on breast cancer risk and screening mammography Women who refrain from undergoing breast cancer screening are believed to be uninformed about risks and usually labeled as irrational. Our purpose in writing this paper is to challenge the traditional notion of rational behaviour, illustrating with qualitative data that people's rationality is influenced by their socio‐cultural and political identities. We explore three major themes: (1) cultural explanations regarding intention to use screening mammography (2) (dis)trust in science and expert opinion, and (3) self‐responsibility and self‐surveillance in caring for one's body. Understanding that women rely on different risk discourses to make decisions about their health should aide researchers, health professionals, and the community in better understanding alternative ways of conceptualizing people's health‐related behaviours when they do not coincide with health authorities recommendations.
Anaesthetic and perioperative management of paediatric organ recipients in nontransplant surgery
Authors: Kostopanagiotou Georgia , Smyrniotis Vassilios , Arkadopoulos Nikolaos , Contis John , Briassoulis George , Kostopanagiotou Elias 
Published: November 2003

SummaryThe number and success rate of paediatric organ transplantation continue to improve yearly, and the number of transplanted children presenting for either elective or emergency nontransplant surgery is expected to increase accordingly. The general considerations related to any transplant recipient are the physiological and pharmacological problems of allograft denervation, the side effects of immunosuppression, the risk of infection, and the potential for rejection. Preoperative assessment of transplant recipients undergoing non‐transplant surgery should focus on graft function, the risk of infection, and function of other organs. Local, regional, or general anaesthesia can be safely delivered to transplant recipients. Specific anaesthetic considerations related to the type of transplantation, have an impact directly on anaesthetic and perioperative management. Since anaesthetists and surgeons in hospitals who are not involved in transplantations, may be required to manage paediatric transplant recipients, the reviews of the existing experience in this field will be valuable tools in their hands.
Laryngeal mask airway guided fibreoptic tracheal intubation in a child with a lingual thyroglossal duct cyst
Authors: Yang Sin Young , Son Soo Chang 
Published: November 2003

SummaryThe establishment of a tracheal airway with direct laryngoscopy can either be difficult or impossible in children with airway pathology. Multiple direct laryngoscopic attempts cause oedema and/or bleeding with subsequent difficult ventilation. The techniques utilizing the laryngeal mask airway (LMATM) and the fibreoptic bronchoscope have been reported. The case of a child with lingual thyroglossal duct cyst in which the LMA was useful to secure the airway and as a conduit for fibreoptic tracheal intubation is reported.