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A Cresswell

Publications and source records attributed to A Cresswell.

10 recordsLinked to original sources
PubMed2001

Use of amplified fragment length polymorphism markers to assess genetic diversity of Lolium species from Portugal.

We evaluated the use of amplified fragment length polymorphism (AFLP) markers to distinguish genotypes, populations and species of Lolium. Accessions of two species Lolium perenne and Lolium multiflorum and their hybrid Lolium x hybridum, collected by the Institute of Grass and Environmental Research in 1995 from locations across Portugal, were used. The genetic variation within and between populations from the extremes of latitude and altitude was determined and assessed. Three primer pair combinations generated 765 polymorphic bands. Principal coordinate analysis of similarities between 127 plants showed high dimensionality in the data. Axes 1-3 were associated primarily with species differences, axes 4-14 with population differences within species and axis 15 onwards with within population differences. UPGMA analysis confirmed the groupings. The three populations of L. perenne formed a discrete cluster widely separated from all other populations. There were two distinct groups of L. x hybridum, of which one was similar to and overlapped with L. multiflorum and the second formed a distinct cluster. Analyses of individual bands showed that every inter- and intraspecific contrast involved a different sets of bands, again confirming the high dimensionality of the data. No single band was strictly diagnostic of any population or species. Nevertheless, the UPGMA analysis showed little or no overlap between populations. Thus, despite the high ratio of within-to-between population genetic variance, the full AFLP banding pattern of each genotype is a relatively reliable fingerprint diagnostic of its parent population. The high dimensionality implies that many different factors contribute to the differences observed. This adds to the potential value of the methodology, since it implies that there is a reasonably high likelihood of finding bands relevant to a given environmental gradient or other factor influencing the distribution of genetic diversity.

Cluster Analysis↗
PubMed2000

Compartment syndrome in a patient with X-linked agammaglobulinaemia and ecthyma gangrenosum. Case report.

Compartment syndrome is a surgical emergency that requires immediate decompression. We know of no documented cases that describe ecthyma gangrenosum as a primary cause of compartment syndrome. We present a case of a baby with x-linked agammaglobulinaemia who developed compartment syndrome associated with systemic Pseudomonas aeruginosa infection and ecthyma gangrenosum of the leg. He was treated by debridement and fasciotomies followed by primary closure and skin grafting and made an uneventful recovery.

Agammaglobulinemia↗
PubMed2000

The nitrogen handling characteristics of white clover (Trifolium repens L.) cultivars and a perennial ryegrass (Lolium perenne L.) cultivar.

Ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.) have contrasting responses to soil mineral N availability and clover has the ability to fix atmospheric N(2) symbiotically. It has been hypothesized that these differences are the key to understanding grass-clover coexistence and vegetative dynamics in pastures. However, the whole plant response of clover and ryegrass to mineral N availability has not been fully characterized and inter-cultivar variability in the N-handling dynamics of clover has not been assessed. A detailed experimental study to address these issues was undertaken. For all clover cultivars and ryegrass, mass specific mineral N uptake rates (of whole plants) were similar saturating functions of mineral N availability. For all clover cultivars total N assimilation rates, whole plant C : N ratios and root : shoot ratios were independent of mineral N availability. Clover growth rates were also independent of mineral N availability except for a slight (<10%) reduction at very low N availability levels. Specific N(2) fixation rate (whole plant) was precisely controlled to ensure fixation balanced the deficit between mineral N uptake and the total N assimilation required to maintain constant whole plant C : N ratio. There was always a deficit between N uptake and the total N assimilation required to maintain C : N ratio. Consequently, some N(2) fixation remained engaged even at high mineral N availability levels. All inter-cultivar variation in N(2) fixation dynamics could be attributed to variations in growth rate. Clover mass specific growth rate declined as plant size increased. Ryegrass specific growth rate, whole plant C : N ratio and root : shoot ratio were dependent on N availability. Increased N availability led to increased growth rate and decreased C : N and root : shoot ratios. Specific growth rate was also dependent on plant size, growth rate declining as plant size increased. It is concluded that clover inter-cultivar variation in field performance is unlikely to be a consequence of variation in N-handling characteristics. Inter-cultivar differences in growth rate are likely to be a much more important source of variation.

Nitrogen↗
PubMed2000

Predictors of infectious complications after burn injuries in children.

BACKGROUND: Infections are the major life-threatening complication of burn injury and occur with the greatest frequency in children. Knowledge of their occurrence and management, however, is extrapolated from studies in adults. We performed a prospective study of infectious complications in burned children. OBJECTIVE: To delineate epidemiology, risk factors and microbiology of infections in burned children where burn care and surgical interventions are optimal. METHODS: Children hospitalized for burns were entered into prospective study. Characteristics of the burn injury were assessed, and active surveillance for infections was performed. RESULTS: Seventy patients were entered [mean age, 42 months; mean total body surface area (TBSA), burn 15%]. Twenty-seven percent of patients developed 39 infections: 13 involved the burn wound (burn wound sepsis, 6; graft loss, 5; and cellulitis, 2); 13 were catheter-associated septicemia; 13 involved other sites (i.e. pneumonia, 4; urinary tract infection, 3; bacteremia, 2; endocarditis, 1; myocardial abscess, 1; toxin-mediated syndrome, 1; and otitis media, 1). Twenty-three infections were caused by a single organism, 9 infections by more than 1 organism and in 7 infections defined by CDC criteria no organism was recovered. Organisms causing infection were: Staphylococcus aureus, 19; Candida albicans, 4; Pseudomonas aeruginosa, 4; coagulase-negative Staphylococcus, 4; Enterococcus sp., 3; Escherichia coli, 1; Klebsiella oxytoca, 1; Serratia marcescens, 1; Streptococcus pneumoniae, 1; Streptococcus pyogenes, 1; Aspergillus fumigatus, 1; and Candida parapsilosis, 1. Burn mechanism (flame and inhalation), extent (TBSA >30%) and depth (full thickness) were risk factors for infection; young age and site of burn were not. CONCLUSION: The most common infections occurring in burn children are burn wound infections and catheter-associated septicemia. Characteristics of burn injury predict risk of infection. Children with flame and inhalation injury, TBSA burned >30% and full thickness burns are at high risk of infectious complications.

Burns↗
PubMed1999

Preparatory trunk motion accompanies rapid upper limb movement.

Evaluation of trunk movements, trunk muscle activation, intra-abdominal pressure and displacement of centres of pressure and mass was undertaken to determine whether trunk orientation is a controlled variable prior to and during rapid bilateral movement of the upper limbs. Standing subjects performed rapid bilateral symmetrical upper limb movements in three directions (flexion, abduction and extension). The results indicated a small (0.4-3.3 degrees) but consistent initial angular displacement between the segments of the trunk in a direction opposite to that produced by the reactive moments resulting from limb movement. Phasic activation of superficial trunk muscles was consistent with this pattern of preparatory motion and with the direction of motion of the centre of mass. In contrast, activation of the deep abdominal muscles was independent of the direction of limb motion, suggesting a non-direction specific contribution to spinal stability. The results support the opinion that feedforward postural responses result in trunk movements, and that orientation of the trunk and centre of mass are both controlled variables in relation to rapid limb movements.

Abdominal Muscles↗
PubMed1993

Phylogenetic grouping and identification of Rhizobium isolates on the basis of random amplified polymorphic DNA profiles.

Through the use of a single, random 15mer as a primer, between 1 and 12 DNA amplification products were obtained per strain from a selection of 84 Rhizobium and Bradyrhizobium isolates. A principal-coordinate analysis was used to analyse the resulting amplified DNA profiles and it was possible to assign isolates to specific groupings. Within the species Rhizobium leguminosarum, the biovar phaseoli formed a distinct group from the other biovars of the species, viciae and trifolii, which grouped together. Isolates of Rhizobium meliloti and Bradyrhizobium species formed their own clear, specific groups. Although it was possible to identify individual isolates on the basis of differences in their amplified DNA profiles, there was evidence that some amplified segments were conserved among individuals at the biovar and species levels.

Base Sequence↗
PubMed1992

Characterisation of Rhizobium isolates by amplification of DNA polymorphisms using random primers.

The use of single random primers, selected in the absence of target sequence information, has been shown to be effective in producing DNA amplifications that provide fingerprints which are unique to individual organisms. DNA amplification by random priming was applied to the DNA from isolates of Rhizobium leguminosarum biovar trifolii. Amplification products were produced using a number of primers, and the resulting fingerprints allowed strain differentiation. However, the effectiveness of primers was dependent upon length and GC content. It was also possible to amplify DNA directly from cells in culture and in nodule tissue. Lysis of these cells was achieved simply through heat applied in the initial DNA denaturation stage of the thermal reaction. The ability to produce varied amplification patterns from different Rhizobium isolates, especially directly from nodules, gives this method potential for use in examining genetic structures and relationships in Rhizobium populations.

Base Sequence↗
PubMedDate not supplied

Study of antibiotic prophylaxis during burn wound debridement in children.

Twenty-three children completed a randomized, prospective, partially blinded study performed to assess the need and effectiveness of antibiotic prophylaxis at the time of burn wound debridement and grafting. Patients with a total body surface area (TBSA) burn less than 35% were randomized to receive cefazolin or placebo. Patients with burns of 35% or more TBSA were randomized to receive cefazolin or targeted antibiotics based on surveillance cultures. Blood cultures were obtained at commencement, immediately after, and 24 hours after surgical debridement. Quantitative cultures and histologic examination of biopsied burn wounds were performed. Burn wound infection occurred in three patients with burns of less than 35% TBSA, two in the cefazolin group and one in the placebo group. Quantitative tissue cultures and histologic examination did not predict either infection. During the four procedures in three patients with 35% or more TBSA, three were randomized to receive cefazolin, and one targeted antibiotics. All receiving cefazolin developed burn wound infection. Quantitative tissue culture was more than 10(5) colony-forming units per gram in all, whereas histologic examination was positive in one. In our patients with less than 35% burn, cefazolin was not necessary, and in those with 35% or more burn, it was not effective.

Antibiotic Prophylaxis↗