Search PubMed⌕ Search

Biomedical subjects

J Beynon

Publications and source records attributed to J Beynon.

At least 37 records · Page 2Linked to original sources
PubMed1998

Differential expression of a senescence-enhanced metallothionein gene in Arabidopsis in response to isolates of Peronospora parasitica and Pseudomonas syringae.

The metallothionein gene, LSC54, shows increased expression during leaf senescence in Brassica napus and Arabidopsis thaliana. A number of abiotic and biotic stresses have been shown to induce senescence-like symptoms in plants and, to investigate this further, the promoter of the LSC54 gene was cloned and fused to the GUS gene and transformed into Arabidopsis. The promoter was highly induced during leaf senescence and also in response to wounding; histochemical analysis indicated that this induction was localised to a few cells close to the wound site. The transgenic Arabidopsis tissue was infected with compatible and incompatible isolates of both the fungal biotroph, Peronospora parasitica and the bacterial necrotroph, Pseudomonas syringae. Incompatible isolates induced rapid cell death (the hypersensitive response) at the site of infection and, with both pathogens, early, localised expression of the GUS gene was observed. In contrast, relatively slow induction of the GUS gene was seen in the compatible interaction and this was correlated with the appearance of senescence-like symptoms in the biotrophic interaction and cell death by necrosis that occurred in response to the necrotrophic pathogen. These results suggest that there are common steps in the signalling pathways that lead to cell death in the hypersensitive response, pathogen induced necrosis and senescence.

Arabidopsis↗
PubMed1998

Genetic characterization of RRS1, a recessive locus in Arabidopsis thaliana that confers resistance to the bacterial soilborne pathogen Ralstonia solanacearum.

The soilborne, vascular pathogen Ralstonia solanacearum, the causative agent of bacterial wilt, was shown to infect a range of Arabidopsis thaliana accessions. The pathogen was capable of infecting the Col-5 accession in an hrp-dependent manner, following root inoculation. Elevated bacterial population levels were found in leaves of Col-5, 4 to 5 days after root inoculation by the GMI1000 strain. Bacteria were found predominantly in the xylem vessels and spread systematically throughout the plant. The Nd-1 accession of A. thaliana was resistant to the GMI1000 strain of R. solanacearum. Bacterial concentrations detected in leaves of Nd-1, inoculated with an hrp+ strain of R. solanacearum, were only slightly higher than those detected in the susceptible accession, Col-5, following inoculation with a strain whose hrp gene cluster was deleted. Leaf inoculation of the GMI1000 strain on the resistant accession Nd-1 induced the formation of lesions in the older leaves of the rosette whereas the same strain of R. solanacearum provoked complete wilting of Col-5. Resistance to strain GMI1000 of R. solanacearum segregated as a simply inherited recessive trait in a genetic cross between Col-5 and Nd-1. F9 recombinant inbred lines generated between these two accessions were used to map a locus, RRS1, that was the major determinant of resistance between restriction fragment length polymorphism markers mi83 and mi61 on chromosome V. This region of the A. thaliana genome is known to contain many other pathogen recognition capabilities.

Arabidopsis↗
PubMed1997

Evaluating an osteoporosis service using a focus group.

Evaluation of any service should determine whether the service meets patients' perceived needs as well as their identified medical needs. This article describes the use of a focus group to evaluate a service for women with a diagnosis of osteoporosis.

Aged↗
PubMed1997

Enoxaparin, a low-molecular-weight heparin suppresses prothrombin activation more effectively than unfractionated heparin in patients treated for venous thromboembolism.

Although unfractionated heparin (UFH) is standard therapy for venous thromboembolism, there is a clinical failure rate of up to 10%. Newer treatment strategies include low-molecular-weight heparins (LMWH). As part of an international study comparing the efficacy and safety of enoxaparin, a LMWH versus UFH in patients with venous thromboembolism, we studied the effects of enoxaparin and UFH on the plasma concentrations of two activation peptides, fragment 1 + 2 (F1 + 2), and thrombin-antithrombin III (TAT) complexes. We hypothesized that enoxaparin would be more effective in suppressing activation of coagulation. Intravenous heparin was given by bolus injection followed by infusion. There were 2 enoxaparin treatment groups (1 mg/kg s.c., bid and 1.5 mg/kg s.c. daily). Plasma samples were obtained from 11 patients in the enoxaparin group and 6 patients in the heparin group prior to and at 6 hour intervals after initiating therapy. Clinical characteristics of the enoxaparin and UFH patient groups were similar. TAT concentrations were not statistically different between groups at any treatment interval. However, plasma F1 + 2 concentrations differed significantly (p < 0.05); concentrations in the enoxaparin group were consistently lower over time than in the UFH group. These results suggest that this LMWH is more effective in suppressing ongoing thrombosis in vivo than UFH in patients with venous thrombosis.

Adult↗
PubMed1997

Surgical management of anorectal incontinence due to internal anal sphincter deficiency.

BACKGROUND: The aetiology, surgical management and outcome in 15 patients with anorectal incontinence due to internal and sphincter (IAS) deficiency as a result of previous anal surgery (n = 14) or penetrating trauma (n = 1) was studied. METHODS: The degree of anorectal incontinence was scored by the Cleveland Clinic system; median score was 14 (range 11-16) before surgery. In all patients the anal sphincter mechanism was assessed by endoanal ultrasonography. Thirteen of the 15 patients underwent either rotation (n = 5), island (n = 5) or advancement (n = 3) anoplasty to correct the contour defect in the anal canal. In the remaining two patients direct IAS repair was performed. RESULTS: Four of the 13 patients who underwent anoplasty developed wound breakdown as the result of infection (n = 3) or inadvertent suture removal (n = 1). A defunctioning stoma was required in three of these patients but all of these have been closed. At median follow-up of 34 (range 6-72) months, all patients who underwent anoplasty have normal defaecatory control and a median continence score of 2 (range 0-4). Direct IAS repair produced no symptomatic improvement in either patient. CONCLUSION: These results suggest that anoplasty deserves further evaluation in the treatment of anorectal incontinence due to discrete IAS defects, but that the place of IAS repair remains uncertain.

Adult↗
PubMed1995

A case of pneumatosis coli managed by restorative proctectomy and ileal pouch-anal anastomosis.

Pneumatosis coli is a rare condition in which gas filled cysts occur in the wall of the intestines. Most symptomatic patients can be managed conservatively but those who fail medical management or who develop bowel obstruction will require surgery. Surgery usually involves a limited colectomy with a potential for recurrence. We describe a case of pneumatosis coli managed successfully by restorative proctocolectomy and ileal pouch-anal anastomosis.

Anastomosis, Surgical↗
PubMed1994

Alfalfa yield response to inoculation with recombinant strains of Rhizobium meliloti with an extra copy of dctABD and/or modified nifA expression.

The construction of rhizobial strains which increase plant biomass under controlled conditions has been previously reported. However, there is no evidence that these newly constructed strains increase legume yield under agricultural conditions. This work tested the hypothesis that carefully manipulating expression of additional copies of nifA and dctABD in strains of Rhizobium meliloti would increase alfalfa yield in the field. The rationale for this hypothesis is based on the positive regulatory role that nifA plays in the expression of the nif regulon and the fact that a supply of dicarboxylic acids from the plant is required as a carbon and energy source for nitrogen fixation by the Rhizobium bacteroids in the nodule. These recombinant strains, as well as the wild-type strains from which they were derived, are ideal tools to examine the effects of modifying or increasing the expression of these genes on alfalfa biomass. The experimental design comprised seven recombinant strains, two wild-type strains, and an uninoculated control. Each treatment was replicated eight times and was conducted at four field sites in Wisconsin. Recombinant strain RMBPC-2, which has an additional copy of both nifA and dctABD, increased alfalfa biomass by 12.9% compared with the yield with the wild-type strain RMBPC and 17.9% over that in the uninoculated control plot at the site where soil nitrogen and organic matter content was lowest. These increases were statistically significant at the 5% confidence interval for each of the three harvests made during the growing season. Strain RMBPC-2 did increase alfalfa biomass at the Hancock site; however, no other significant increases or decreases in alfalfa biomass were observed with the seven other recombinant strains at that site. At three sites where this experiment was conducted, either native rhizobial populations or soil nitrogen concentrations were high. At these sites, none of the recombinant strains affected yield. We conclude that RMBPC -2 can increase alfalfa yields under field conditions of nitrogen limitation, low endogenous rhizobial competitors, and sufficient moisture.

Base Sequence↗
PubMed1994

Rectum.

Explore the source record for details and available documents.

Humans↗
PubMed1993

Anal endosonography and correlation with in vitro and in vivo anatomy.

The endosonographic anatomy of the anal sphincters was studied by in vivo and in vitro correlation with anatomical dissection. Fourteen fresh anorectal specimens (eight abdominoperineal resection, six post mortem) were scanned in a water-bath with sequential dissection and correlation with the ultrasonographic images. Accurate anatomical identification of the layers during dissection was confirmed histologically. Anal endosonography was performed during operation in 12 patients to validate the in vitro findings. The in vivo study confirmed the in vitro results. Basic endosonographic anatomy has been clarified and inaccuracies in the previous description of the longitudinal muscle and external anal sphincter corrected.

Adult↗