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Biomedical subjects

R Waugh

Publications and source records attributed to R Waugh.

At least 19 recordsLinked to original sources
PubMed2004

Long-term outcome of radiological-guided insertion of implanted central venous access port devices (CVAPD) for the delivery of chemotherapy in cancer patients: institutional experience and review of the literature.

Central venous access port devices (CVAPD) are necessary for delivery of prolonged infusional chemotherapy or in patients with poor peripheral venous access. Previous studies of Hickman catheters report complication rates in about 45% of patients. Our aim was to assess the early and late complication rate, and duration that the CVAPD remained functional, following insertion by interventional radiologists in patients with solid tumours. A prospective study was undertaken in 110 consecutive patients who had insertion of 111 subclavian CVAPD. The median age of patients was 57 years (range 17-83), 64 were females; 68 patients (61%) had gastrointestinal tumours and 25 (23%) had breast cancer. CVAPD were successfully implanted in all but one patient. There were four (4%) immediate major complications: thrombosis 2 and pneumothorax 2. Nine patients (8%) had bruising or pain. Four devices (4%) became infected. In total, 100 CVAPD (90%) were either removed as planned at the end of treatment (n=23) after a median 203 days, or remained in situ for a median of 237 days (7-1133). Premature removal occurred in eight patients due to infection (n=4), thrombosis (n=3) or faulty device (n=1). Four patients were lost to follow-up. Radiological insertion of CVAPD is safe and convenient with low rates of complications.

Antineoplastic Agents↗
PubMed2003

Selection of highly informative and user-friendly microsatellites (SSRs) for genotyping of cultivated potato.

Characterization of nearly 1,000 cultivated potato accessions with simple sequence repeats (SSRs; also referred to as microsatellites) has allowed the identification of a reference set of SSR markers for accurate and efficient genotyping. In addition, 31 SSRs are reported here for a potato genetic map, including new map locations for 24 of them. A first criterion for this proposed reference set was ubiquity of the SSRs in the eight landrace cultivar groups of the potato, Solanum tuberosum. All SSRs tested in the present study displayed the same allele phenotypes and allele size range in the diverse germplasm set as in the advanced potato cultivar germplasm in which they were originally discovered. Thirteen of 13 SSR products from all cultivar groups are shown to cross-hybridize with the corresponding SSR product of the source cultivar to ascertain sequence homology. Other important SSR selection criteria are quality of amplification products, locus complexity, polymorphic index content, and well-dispersed location on a potato genetic map. Screening of 156 SSRs allowed the identification of a highly informative and user-friendly set comprising 18 SSR markers for use in characterization of potato genetic resources. In addition, we have identified true- and pseudo-multiplexing SSRs for even greater efficiency.

Alleles↗
PubMed2003

Dissection of resistance to soil-borne yellow-mosaic-inducing viruses of barley (BaMMV, BaYMV, BaYMV-2) in a complex breeders' cross by means of SSRs and simultaneous mapping of BaYMV/BaYMV-2 resistance of var. 'Chikurin Ibaraki 1'.

Ninety-three F(1)-derived doubled haploid (DH) lines from a complex breeders' cross involving the Japanese genotype 'Chikurin Ibaraki 1', which is resistant to barley mild mosaic virus (BaMMV) and two strains of barley yellow mosaic virus (BaYMV and BaYMV-2), three susceptible varieties ('Hamu', 'Julia' and a breeding line) and cv. 'Carola', which carries rym4 conferring resistance to BaMMV and BaYMV, were analysed for resistance to BaMMV, BaYMV and BaYMV-2. The DH lines fell into four phenotypic classes. In addition to completely resistant and susceptible genotypes, DHs were observed which were either resistant to BaMMV and BaYMV or to BaYMV and BaYMV-2. For BaMMV and BaYMV-2 resistance, segregation ratios approaching 1r:1s were observed, suggesting the presence of single resistance genes. In contrast, the segregation ratio for BaYMV fits a 3r:1s segregation ratio, suggesting the presence of two independently inherited genes. From the genetic analysis, we conclude that a resistance locus effective against BaYMV and BaYMV-2 originates from Chikurin Ibaraki 1 and segregates independently from the Carola-derived rym4 resistance that is effective against BaYMV and BaMMV. The BaMMV resistance in Chikurin Ibaraki 1 has probably been lost during population development. This hypothesis was tested using a simple-sequence repeat (SSR) marker (Bmac29) linked to rym4. All BaMMV-resistant DH lines supported amplification of the rym4-resistance diagnostic allele. To identify the genetic location of the Chikurin Ibaraki 1-derived resistance against BaYMV/BaYMV-2, bulked DNA samples were constructed from the four resistance classes, and bulked segregant analysis was performed using a genome-wide collection of SSRs. Differentiating alleles were observed at two linked SSRs on chromosome 5H. The location of this BaYMV/BaYMV-2 resistance locus was confirmed and further resolved by linkage analysis on the whole population using a total of five linked SSRs.

Genes, Plant↗
PubMed2003

Development and characterization of recombinant chromosome substitution lines (RCSLs) using Hordeum vulgare subsp. spontaneum as a source of donor alleles in a Hordeum vulgare subsp. vulgare background.

The ancestor of barley (Hordeum vulgare subsp. spontaneum) may be a source of novel alleles for crop improvement. We developed a set of recombinant chromosome substitution lines (RCSLs) using an accession of H. vulgare subsp. spontaneum (Caesarea 26-24, from Israel) as the donor and Hordeum vulgare subsp. vulgare 'Harrington' (the North American malting quality standard) as the recurrent parent via two backcrosses to the recurrent parent, followed by six generations of selfing. Here we report (i) the genomic architecture of the RCSLs, as inferred by simple sequence repeat (SSR) markers, and (ii) the effects of H. vulgare subsp. spontaneum genome segment introgressions in terms of three classes of phenotypes: inflorescence yield components, malting quality traits, and domestication traits. Significant differences among the RCSLs were detected for all phenotypes measured. The phenotypic effects of the introgressions were assessed using association analysis, and these were referenced to quantitative trait loci (QTL) reported in the literature. Hordeum vulgare subsp. spontaneum, despite its overall inferior phenotype, contributed some favorable alleles for agronomic and malting quality traits. In most cases, the introgression of the ancestral genome resulted in a loss of desirable phenotypes in the cultivated parent. Although disappointing from a plant breeding perspective, this finding may prove to be a useful tool for gene discovery.

Alleles↗
PubMed2002

Analysis of potential duplicates in barley gene bank collections using re-sampling of microsatellite data.

Redundant duplication among putative Nordic spring barley material held at 12 gene banks worldwide was studied using 35 microsatellite primer pairs covering the entire barley genome. These microsatellite markers revealed an average of 7.1 alleles per locus, and a range of 1 to 17 different alleles per locus. Similarity of accession name was initially used to partition the 174 repatriated accessions into 36 potential duplicate groups, and one group containing 36 apparently unique or unrelated accessions. This partitioning was efficient to produce a distribution of mainly small average genetic distances within potential duplicate groups compared to distances from the group of unique accessions. However, comparisons within potential duplicate groups still contained large genetic distances of the same size as distances between unique accessions indicating classification errors. A bootstrap approach based on re-sampling of both microsatellite markers and alleles within marker loci was used to test for homogeneity within potential duplicate groups. The test was used in each group for sequential elimination of accessions with a significantly large average genetic distance to identify a homogeneous group. Such genetically homogeneous groups of two or more accessions were identified in 22 among the 36 potential duplicate groups studied. Results from the genetic analysis of some potential duplicate groups supported previous conclusions based on passport data through inclusion of the historically most-original accession in the genetically homogeneous group. In other potential duplicate groups the apparently most-original accession according to passport data was not included in the homogeneous set of accessions, indicating that this most-original accession does not have duplicate accessions in the group. During the present study the largest average genetic distance accepted in any homogeneous group was smaller than the smallest distance declared significant in any group, with a threshold average genetic distance of approximately 0.14. The results are discussed with respect to the identification of duplicate accessions within potential duplicate groups, as well as the elimination of genetic off types in such groups. Furthermore, large barley gene bank collections may be screened for potential duplicates with genetic distances below the suggested threshold of 0.14.

Gene Library↗
PubMed2002

QTLs for grain carbon isotope discrimination in field-grown barley.

In several crops including cereals, carbon isotope discrimination (Delta) has been associated with drought tolerance in terms of water-use efficiency and yield stability in drought-prone environments. By using a complete genetic map generated from 167 recombinant inbred lines from a cross between Tadmor and Er/Apm, QTLs associated with grain Delta have been detected in barley grown in three Mediterranean field environments, two differing only in water availability. Ten QTLs were identified: one was specific to one environment, two presented interaction with the environment, six presented main effects across three or two environments and one presented both effects. Heading date did not contribute to the environment (E) and G x E effects acting on Delta. Seasonal rainfall and the ratio of rainfall to evapo-transpiration made large contributions to the environmental effect, but their influence on G x E was weaker. Eight QTLs for Delta co-located with QTLs for physiological traits related to plant water status and/or osmotic adjustment, and/or for agronomic traits previously measured on the same population. Some perspectives in terms of characterising drought tolerance are evoked.

Biomarkers↗
PubMed2002

Integrin activation by divalent ions affects neutrophil homotypic adhesion.

Activation of beta 2 integrins on leukocytes, via receptor clustering or affinity changes, is a key step in the inflammatory response. To evaluate the importance of integrin affinity changes for the formation of adhesive contacts, divalent cations were used to modulate beta 2-integrin affinity without causing a general activation of neutrophils. Two neutrophils were brought into repeated contact with micropipettes and the probability of forming an adhesive contact was measured for neutrophils exposed to different cations. In the presence of magnesium and manganese, which induce a high affinity integrin conformation, the adhesion frequency was 12%-14%. In the presence of calcium (which stabilizes the low-affinity state) the frequency of adhesion was reduced (2.4 +/- 2.1%) and in the absence of divalent cations there were no adhesive contacts. The adhesive probability was not affected by addition of soluble VCAM-1, but was significantly reduced to 7 +/- 3% in the presence of magnesium plus a soluble form of ICAM-1. Addition of a blocking anti-beta 2-integrin Fab fragment also significantly reduced the probability of forming an adhesive contact to 4 +/- 2%. Thus increased beta 2-integrin affinity promotes homotypic neutrophil adhesion during cell collisions, but the adhesion strength is weak compared to forces observed in cell arrest and migration.

Calcium↗
PubMed2001

Paediatric pelvic imaging: optimisation of dose and technique using digital grid-controlled pulsed fluoroscopy.

BACKGROUND: An audit of paediatric pelvic radiographs identified deficiencies in gonad shield placement and radiographic technique. OBJECTIVE: A technique using grid-controlled fluoroscopy (GCF), with hard copy images in frame grab and digital spot image (DSI) format was evaluated to optimise gonad shield placement and reduce the dose given to children with Perthes disease and Developmental Hip Dysplasia (DDH) attending for pelvic radiography. MATERIALS AND METHODS: Phantom and patient dose surveys of conventional and fluoroscopic techniques were carried out. Image quality and radiation dose were compared for the frame grab and DSI techniques. Retrospective evaluation was undertaken to compare their clinical acceptability. RESULTS: Both fluoroscopic techniques gave considerably less radiation than conventional non-grid radiography (67-83%, P < 0.05). The frame grab technique gave less radiation than DSI (P < 0.05). There was no significant difference in the clinical acceptability scores of the DSI and frame grab images. CONCLUSION: Fluoroscopy acquired images are now used since the fluoroscopic techniques give much less dose than conventional radiography and provide images of sufficient quality for clinical assessment. Indeed, as there was no significant difference in clinical usefulness between the frame grab and DSI techniques, it is planned to use frame grab alone, thus gaining additional dose saving.

Adolescent↗
PubMed2001

Paediatric pelvic imaging: improvement in gonad shield placement by multidisciplinary audit.

BACKGROUND: In 1996, there were local reports of poor gonad protection for paediatric pelvic radiographs. OBJECTIVES: To investigate the nature of the problem and make necessary improvements. MATERIALS AND METHODS: A retrospective audit of 218 paediatric pelvic radiographs was undertaken in 1997. Each radiograph was assessed for the presence of a gonad shield, appropriateness of the device and its position. A multidisciplinary team was formed with representation from radiology, radiography, orthopaedics and medical physics to investigate ways of improving technique and reducing patient dose. These included radiographer training and the introduction of digital fluoroscopy as an alternative imaging technique in follow-up patients. There were further rounds of data collection in 1998 and 1999. RESULTS: In round 1, a gonad shield was present in 77.9 % of boys' films and 76 % of girls' films where one should have been, increasing to 85.2 % and 85.4 % respectively by round 3 of the audit (P < 0.05). Only 31.6 % of boys' devices and 21.9 % of girls' devices were correctly positioned in round 1, increasing to 78.3 % and 94.3 %, respectively, by round 3 of the audit (P < 0.05). After round 1, no inappropriate devices were used. CONCLUSION: Audit was an effective tool in gaining the resources needed to improve technique and reduce radiation exposure in children. The multidisciplinary approach was vital in the success of this project.

Child, Preschool↗
PubMed2001

Physical mapping across an avirulence locus of Phytophthora infestans using a highly representative, large-insert bacterial artificial chromosome library.

The oomycete plant pathogen Phytophthora infestans is the causal agent of late blight, one of the most devastating diseases of potato worldwide. As part of efforts to clone avirulence (Avr) genes and pathogenicity factors from P. infestans, we have constructed a bacterial artificial chromosome (BAC) library from an isolate containing six Avr genes. The BAC library comprises clones with an average insert size of 98 kb and represents an estimated 10 genome equivalents. A three-dimensional pooling strategy was developed to screen the BAC library for amplified fragment length polymorphism (AFLP) markers, as this type of marker has been extensively used in construction of a P. infestans genetic map. Multiple positive clones were identified for each AFLP marker tested. The pools were used to construct a contig of 11 BAC clones in a region of the P. infestans genome containing a cluster of three avirulence genes. The BAC contig is predicted to encompass the Avr11 locus but mapping of the BAC ends will be required to determine if the Avr3 and Avr10 loci are also present in the BAC contig. These results are an important step towards the positional cloning of avirulence genes from P. infestans, and the BAC library represents a valuable resource for largescale studies of oomycete genome organisation and gene content.

Chromosomes, Artificial, Bacterial↗
PubMed2001

Linkages between facial expressions of anger and transient myocardial ischemia in men with coronary artery disease.

The authors examined whether facial expressions of emotion would predict changes in heart function. One hundred fifteen male patients with coronary artery disease underwent the Type A Structured Interview, during which time measures of transient myocardial ischemia (wall motion abnormality and left ventricular ejection fraction) were obtained. Facial behavior exhibited during the ischemia measurement period was videotaped and later coded by using the Facial Action Coding System (P. Ekman & W. V. Friesen, 1978). Those participants who exhibited ischemia showed significantly more anger expressions and nonenjoyment smiles than nonischemics. Cook-Medley Hostility scores did not vary with ischemic status. The findings have implications for understanding how anger and hostility differentially influence coronary heart disease risk.

Adult↗
PubMed2001

Improved survival after endoluminal repair with second-generation prostheses compared with open repair in the treatment of abdominal aortic aneurysms: a 5-year concurrent comparison using life table method.

PURPOSE: The aim of this study was to compare the outcome of consecutive patients with abdominal aortic aneurysm (AAA) treated concurrently by means of open repair (OR) and endoluminal repair (ER) with second-generation prostheses by the same surgeons during a defined interval. METHODS: Between May 1995 and December 1998 second-generation (low profile, fully supported, modular) endoprostheses were implanted in 148 patients. These patients, together with 135 patients treated concurrently with OR during the same period, comprised the study group of 283 patients. Patient selection was based on aneurysm morphology. Those patients who were anatomically suitable for ER were treated with this method. The ER and OR groups were similar with regard to age, sex, and size of AAA. The ER group contained high-risk patients considered unfit for OR (n = 46), and the OR group contained high-risk patients who were anatomically unsuitable for ER (n = 19). Outcome criteria in both groups were survival and successful aneurysm repair. Success in the ER group was defined as exclusion of the aneurysm sac and stability or reduction in AAA maximum transverse diameter. Persistent endoleaks were classified as failures, regardless of whether they were subsequently corrected with secondary endovascular intervention. Data were analyzed with the life table method. The minimum period of follow-up for all patients was 18 months. RESULTS: The perioperative mortality rate was 5.9% in the OR group and 2.7% in the ER group (not significant). There was a statistically significant difference between the survival curves of the two groups in favor of the ER group when analyzed with the log-rank test (P =.004). The Kaplan-Meier curve for graft failure for the ER group revealed a 3-year graft success probability of 82%. Survival probability with successful repair in the OR group at 3 years was 85%. CONCLUSIONS: A concurrent comparison of ER with second-generation prostheses versus OR demonstrated a significant difference in survival in favor of the ER group. The probability of survival with successful repair at 3 years was similar in both groups.

Aged↗
PubMed2000

Exercise and weight loss reduce blood pressure in men and women with mild hypertension: effects on cardiovascular, metabolic, and hemodynamic functioning.

BACKGROUND: Lifestyle modifications have been recommended as the initial treatment strategy for lowering high blood pressure (BP). However, evidence for the efficacy of exercise and weight loss in the management of high BP remains controversial. METHODS: One hundred thirty-three sedentary, overweight men and women with unmedicated high normal BP or stage 1 to 2 hypertension were randomly assigned to aerobic exercise only; a behavioral weight management program, including exercise; or a waiting list control group. Before and following treatment, systolic and diastolic BPs were measured in the clinic, during daily life, and during exercise and mental stress testing. Hemodynamic measures and metabolic functioning also were assessed. RESULTS: Although participants in both active treatment groups exhibited significant reductions in BP relative to controls, those in the weight management group generally had larger reductions. Weight management was associated with a 7-mm Hg systolic and a 5-mm Hg diastolic clinic BP reduction, compared with a 4-mm Hg systolic and diastolic BP reduction associated with aerobic exercise; the BP for controls did not change. Participants in both treatment groups also displayed reduced peripheral resistance and increased cardiac output compared with controls, with the greatest reductions in peripheral resistance in those in the weight management group. Weight management participants also exhibited significantly lower fasting and postprandial glucose and insulin levels than participants in the other groups. CONCLUSIONS: Although exercise alone was effective in reducing BP, the addition of a behavioral weight loss program enhanced this effect. Aerobic exercise combined with weight loss is recommended for the management of elevated BP in sedentary, overweight individuals.

Adult↗
PubMed2000

UK CropNet: a collection of databases and bioinformatics resources for crop plant genomics.

The UK Crop Plant Bioinformatics Network (UK CropNet) was established in 1996 in order to harness the extensive work in genome mapping in crop plants in the UK. Since this date we have published five databases from our central UK CropNet WWW site (http://synteny.nott.ac.uk/) with a further three to follow shortly. Our resource facilitates the identification and manipulation of agronomically important genes by laying a foundation for comparative analysis among crop plants and model species. In addition, we have developed a number of software tools that facilitate the visualisation and analysis of our data. Many of our tools are made freely available for use with both crop plant data and with data from other species.

Crops, Agricultural↗