A high-density microsatellite consensus map for bread wheat (Triticum aestivum L.)

A microsatellite consensus map was constructed by joining four independent genetic maps of bread wheat. Three of the maps were F(1)-derived, doubled-haploid line populations and the fourth population was 'Synthetic' x 'Opata', an F(6)-derived, recombinant-inbred line population. Microsatellite markers from different research groups including the Wheat Microsatellite Consortium, GWM, GDM, CFA, CFD, and BARC were used in the mapping. A sufficient number of common loci between genetic maps, ranging from 52 to 232 loci, were mapped on different populations to facilitate joining the maps. Four genetic maps were developed using MapMaker V3.0 and JoinMap V3.0. The software CMap, a comparative map viewer, was used to align the four maps and identify potential errors based on consensus. JoinMap V3.0 was used to calculate marker order and recombination distances based on the consensus of the four maps. A total of 1,235 microsatellite loci were mapped, covering 2,569 cM, giving an average interval distance of 2.2 cM. This consensus map represents the highest-density public microsatellite map of wheat and is accompanied by an allele database showing the parent allele sizes for every marker mapped. This enables users to predict allele sizes in new breeding populations and develop molecular breeding and genomics strategies.

Experience with femoro-popliteal vein as a conduit for vascular reconstruction in infected fields

OBJECTIVE

to review the outcome of femoro-popliteal vein grafts for arterial reconstruction in the presence of sepsis.

PATIENTS AND METHODS

twenty-six patients underwent 27 arterial reconstructions with femoro-popliteal vein in the presence of infection. Five had mycotic aneurysms (3 aortic, 1 iliac and 1 femoral), 21 had prosthetic graft infections (9 aortic, 8 femoro-femoral, 2 axillo-femoral, 1 ilio-femoral and 1 femoral dacron patch) and one underwent superior mesenteric artery reconstruction following ischaemic small bowel perforation.Arterial reconstruction followed debridement of infected tissue, removing any infected graft, povidone iodine washout and appropriate antibiotic cover. Where possible, new grafts were placed in a clean field or wrapped in omentum. Four femoral anastomoses were covered by rectus femoris flaps.

RESULTS

there was one early postoperative death (4%) and no limb loss. All others remained free from infection with patent grafts at 1 month to 5 years (median 22 months). Three major wound infections healed without exposing the graft. One infarcted rectus femoris flap required removal. Donor limb swelling was transient. Five required percutaneous angioplasty and one underwent open profundaplasty within 3 months.

CONCLUSION

femoro-popliteal vein reconstruction with debridement and appropriate antibiotic therapy is recommended for the treatment of arterial or graft infections.

Hydrothermal recharge and discharge across 50 km guided by seamounts on a young ridge flank

Hydrothermal circulation within the sea floor, through lithosphere older than one million years (Myr), is responsible for 30% of the energy released from plate cooling, and for 70% of the global heat flow anomaly (the difference between observed thermal output and that predicted by conductive cooling models). Hydrothermal fluids remove significant amounts of heat from the oceanic lithosphere for plates typically up to about 65 Myr old. But in view of the relatively impermeable sediments that cover most ridge flanks, it has been difficult to explain how these fluids transport heat from the crust to the ocean. Here we present results of swath mapping, heat flow, geochemistry and seismic surveys from the young eastern flank of the Juan de Fuca ridge, which show that isolated basement outcrops penetrating through thick sediments guide hydrothermal discharge and recharge between sites separated by more than 50 km. Our analyses reveal distinct thermal patterns at the sea floor adjacent to recharging and discharging outcrops. We find that such a circulation through basement outcrops can be sustained in a setting of pressure differences and crustal properties as reported in independent observations and modelling studies.

Use of superficial femoral/popliteal veins for suprainguinal arterial reconstruction in the presence of infection

Background

Mycotic aneurysms and graft infection in the aortoiliac region provide formidable technical challenges and carry a high morbidity and mortality rate with either of the standard techniques of in situ antibiotic-bonded prosthetic reconstruction or extra-anatomical bypass. This study investigated the use of autologous superficial femoral/popliteal vein (SFPV) for arterial reconstruction in ten patients with arterial or graft infections of the aortoiliac region.

Methods

Two patients with mycotic aortic aneurysms and four with aortic graft infections underwent aortoiliac replacement with SFPV after thorough debridement and/or excision of infected graft material. Three infected femorofemoral grafts were replaced in situ with reversed SFPV and an infected axillofemoral graft was converted to an iliofemoral reversed SFPV graft. All patients received appropriate antibiotic therapy and were followed by regular postoperative duplex imaging. Preoperative femoral vein duplex imaging was performed in eight of ten patients to confirm suitability as a graft.

Results

Nine of the ten patients survived with a functioning graft and without limb loss or evidence of infection at 3–30 months. One patient died from myocardial infarction after operation. Two patients had minor swelling of one leg. Three patients required angioplasty of anastomotic stenoses detected by duplex surveillance at 6 weeks.

Conclusion

SFPV is an excellent conduit for aortic or iliac reconstruction in the presence of infection. Duplex imaging is useful to confirm the suitability of deep veins for use as a graft and for postoperative surveillance.

Evidence-based practice

This article provides an insight into the philosophical assumptions underpinning evidence-based practice (EBP). Lois Goding and Keith Edwards believe that EBP has often been adopted within nursing, midwifery and health visiting without careful consideration of the nature of such evidence. This article explores the issues surrounding different research methodologies and methods, in particular the dichotomous relationships between positivism, constructivism and postmodernism. The authors believe that nursing involves complex, intangible human behaviour that demands an interpretative, holistic approach investigating perceptions rather than a reductionist approach.

Development and mapping of SSR markers for maize

Microsatellite or simple sequence repeat (SSR) markers have wide applicability for genetic analysis in crop plant improvement strategies. The objectives of this project were to isolate, characterize, and map a comprehensive set of SSR markers for maize (Zea mays L.). We developed 1051 novel SSR markers for maize from microsatellite-enriched libraries and by identification of microsatellite-containing sequences in public and private databases. Three mapping populations were used to derive map positions for 978 of these markers. The main mapping population was the intermated B73 x Mo17 (IBM) population. In mapping this intermated recombinant inbred line population, we have contributed to development of a new high-resolution map resource for maize. The primer sequences, original sequence sources, data on polymorphisms across 11 inbred lines, and map positions have been integrated with information on other public SSR markers and released through MaizeDB at URL:www.agron.missouri.edu. The maize research community now has the most detailed and comprehensive SSR marker set of any plant species.

Toward positional cloning of Vgt1, a QTL controlling the transition from the vegetative to the reproductive phase in maize

Vgt1 (Vegetative to generative transition 1) is a quantitative trait locus (QTL) for flowering time in maize (Zea mays L.). Vgt1 was initially mapped in a ca. 5-cM interval on chromosome bin 8.05, using a set of near-isogenic lines (NILs) in the genetic background of the late dent line N28, with the earliness allele introgressed from the early variety Gaspé Flint. A new large mapping population was produced by crossing N28 and one early NIL with a ca. 6-cM long Gaspé Flint introgression at the Vgt1 region. Using PCR-based assays at markers flanking Vgt1, 69 segmental NILs homozygous for independent crossovers near the QTL were developed. When the NILs were tested in replicated field trials for days to pollen shed (DPS) and plant node number (ND), the QTL followed a Mendelian segregation. Using bulk segregant analysis and AFLP profiling, 17 AFLP markers linked to the QTL region were identified. Statistical analysis indicated a substantial coincidence of the effects of Vgt1 on both DPS and ND. Vgt1 was mapped at ca. 0.3 cM from an AFLP marker. As compared to DPS, the higher heritability of ND allowed for a more accurate assessment of the effects of Vgt1. The feasibility of the positional cloning of Vgt1 is discussed.

A major gene effect on fasting insulin and insulin sensitivity in familial combined hyperlipidemia

The most common inherited dyslipidemia, familial combined hyperlipidemia (FCHL), is associated with insulin resistance. Whether insulin sensitivity in these families is inherited is not known. Therefore, we investigated the inheritance of insulin sensitivity in 352 nondiabetic family members from 37 families with FCHL, 105 of whom had undergone testing using the hyperinsulinemic-euglycemic clamp technique for the measurement of insulin sensitivity. First, complex segregation analysis of fasting insulin levels (both unadjusted and age-, age(2)-, and BMI-adjusted) was used for modeling of the variance in fasting insulin levels. In these analyses, Mendelian codominant inheritance (P = 0.320 for unadjusted and P = 0.295 for adjusted insulin values) was not rejected over the most general model and fit the data significantly better than the sporadic model (P < 0.001). Polygenic and environmental models were rejected (P < 0.001). The Mendelian codominant model explained 44 and 45% of the variance in unadjusted and adjusted fasting insulin levels, respectively. The proposed genotypes of this locus, based on segregation analysis, were associated with directly measured insulin sensitivity in 105 FCHL family members who underwent the hyperinsulinemic-euglycemic clamp (P < 0.001). These results provide evidence for a major gene regulating insulin sensitivity in FCHL families. Possible pleiotropic effects of this insulin sensitivity locus on dyslipidemias in FCHL remain to be elucidated.

Comparative analysis of the Band 4.1/ezrin-related protein tyrosine phosphatase Pez from two Drosophila species: implications for structure and function

The FERM-PTPs are a group of proteins that have FERM (Band 4.1, ezrin, radixin, moesin homology) domains at or near their N-termini, and PTP (protein tyrosine phosphatase) domains at their C-termini. Their central regions contain either PSD-95, Dlg, ZO-1 homology domains or putative Src homology 3 domain binding sites. The known FERM-PTPs fall into three distinct classes, which we name BAS, MEG, and PEZ, after representative human PTPs. Here we analyze Pez, a novel gene encoding the single PEZ-class protein present in Drosophila. Pez cDNAs were sequenced from the distantly related flies Drosophila melanogaster and Drosophila silvestris, and found to be highly conserved except in the central region, which contains at least 21 insertions and deletions. Comparison of fly and human Pez reveals several short conserved motifs in the central region that are likely protein binding sites and/or phosphorylation sites. We also identified novel invertebrate members of the BAS and MEG classes using genome data, and generated an alignment of vertebrate and invertebrate FERM domains of each class. 'Specialized' residues were identified that are conserved only within a given class of PTPs. These residues highlight surface regions that may bind class-specific ligands; for PEZ, these residues cluster on and near FERM subdomain F1. Finally, the PTP domain of fly Pez was modeled based on known PTP tertiary structures, and we conclude that Pez is likely a functional phosphatase despite some unusual features of the active site cleft sequences. Biochemical confirmation of this hypothesis and genetic analysis of Pez are currently underway.

Genetic variability among archival cultures of Salmonella typhimurium

The existence in our laboratory of over 10000 Salmonella typhimurium LT2 cultures sealed in agar stab vials for 33-46 years offers an opportunity for evolutionary and mutational studies. In each of 77 vials examined, 10(3)-10(5) colony forming units per vial were recovered (less than 0.01% of the original population) even after decades of undisturbed storage. Considerable genetic variability was observed in these populations. Three genetic variables, chromosome fragment size as determined by pulsed-field gel electrophoresis, extensive mutational reversions from nutritional auxotrophy to prototrophy, and differences in protein content as assayed by sodium dodecyl sulfate polyacrylamide gel electrophoresis, were measured.

Chitosan as a nonviral gene delivery system. Structure-property relationships and characteristics compared with polyethylenimine in vitro and after lung administration in vivo

Chitosan is a natural cationic linear polymer that has recently emerged as an alternative nonviral gene delivery system. We have established the relationships between the structure and the properties of chitosan-pDNA polyplexes in vitro. Further, we have compared polyplexes of ultrapure chitosan (UPC) of preferred molecular structure with those of optimised polyethylenimine (PEI) polyplexes in vitro and after intratracheal administration to mice in vivo. Chitosans in which over two out of three monomer units carried a primary amino group formed stable colloidal polyplexes with pDNA. Optimized UPC and PEI polyplexes protected the pDNA from serum degradation to approximately the same degree, and they gave a comparable maximal transgene expression in 293 cells. In contrast to PEI, UPC was non toxic at escalating doses. After intratracheal administration, both polyplexes distributed to the mid-airways, where transgene expression was observed in virtually every epithelial cell, using a sensitive pLacZ reporter containing a translational enhancer element. However, the kinetics of gene expression differed - PEI polyplexes induced a more rapid onset of gene expression than UPC. This was attributed to a more rapid endosomal escape of the PEI polyplexes. Although this resulted in a more efficient gene expression with PEI polyplexes, UPC had an efficiency comparable to that of commonly used cationic lipids. In conclusion, this study provides insights into the use of chitosan as a gene delivery system. It emphasises that chitosan is a nontoxic alternative to other cationic polymers and it forms a platform for further studies of chitosan-based gene delivery systems.

A comparison of professionals' and patients' understanding of asthma: evidence of emerging dualities?

Despite an increase in the provision of services to patients with asthma, morbidity from the disease remains high. Recent research (outside asthma) has raised the possibility that patients may develop a conceptualisation of illnesses which is not entirely compatible with the prevailing biomedical view. This paper compares the way in which health care professionals and patients with asthma described various aspects of the illness, using an approach which considered the type of knowledge which might be used to construct the respective conceptualisations of asthma. A qualitative method is empliyed, using focus groups. Eight focus groups were convened, four of professionals and four of patients with asthma. Following the initial data analysis, the results were reviewed linguistically, with particular attention to the use of metaphor.The health care professionals and patients participating in this study agreed broadly in their explanations of the aetiology and drug treatment of asthma. The data suggest lack of congruence in the development of treatment strategies and locus of control. Health care professionals and patients in this study used linguistically different metaphors to represent the disease: the former more frequently used metaphors evoking on-going processes, the latter visualising the chest (in their use of metaphor) as a static container, emptying and filling throughout the course of the disease. Two commentaries from philosophical and anthropological literature are considered in order to offer theoretical accounts relevant to this interpretation. The data suggest an emerging duality in the approach to treatment plans, in the roles played by professionals and patients with asthma, and in the different types of knowledge used by professionals and patients to construct their respective working models of asthma.