Search PubMed⌕ Search

Biomedical subjects

L Jones

Publications and source records attributed to L Jones.

At least 37 records · Page 2Linked to original sources
PubMed2001

Femoral pseudoaneurysm thrombinjection.

BACKGROUND: The risk of pseudoaneurysm (PSA) increases with the number of catheterizations performed for cardiovascular diagnosis and therapy. Thrombin injection, or "thrombinjection," is an alternative to ultrasound-guided compression or surgical repair. Thrombinjection is effective and economical, but the specter of systemic arterial thrombosis hinders its wide application. We report cautionary steps taken prior to injection and lessons learned during our first 20 cases. METHODS AND RESULTS: Thrombinjection was performed under ultrasound (US) guidance in 12 women and 8 men with PSA after femoral catheterization. PSA varied in size from 17 to 39 mm with neck openings from 1.5 to 3.9 mm. Under local anesthesia and US longitudinal view, a 20-gauge US needle tip was placed in the PSA away from the neck. With 12 cases under 600 units, 100 to 2,300 units of thrombin (1,000 U/mL) were injected slowly. Slow injection, positioning of the ball of thrombus formed at the needle tip, probe compression, and combined or interchangeable use of US color flow and B-mode were the essential techniques utilized. All PSA thrombosed successfully on the first treatment. One patient had fever and another returned for compression treatment of a second, not recurrent, PSA. CONCLUSIONS: Successful thrombinjection was accomplished by focusing on common femoral artery PSA with small neck openings, avoiding arteriovenous fistulas, and using standard thrombin concentration, US needle, state of the art ultrasonography, slow injection, thrombus ball positioning, and adjunctive probe compression.

Adult↗
PubMed2001

Tautomeric energetics of xanthine oxidase substrates: xanthine, 2-oxo-6-methylpurine, and lumazine.

The stability of the tautomers of each of the three important substrates of xanthine oxidase, xanthine, 2-oxo-6-methylpurine, and lumazine, was examined by quantum mechanical calculations. The geometries of these tautomers were optimized at the AM1, Hartree-Fock (HF/6-31G), and hybrid Hartree-Fock/density functional theory (B3LYP/6-31G(d)) levels of theory. The single point energies of some of the more stable tautomers for each of the substrates were calculated at the B3LYP/6-311 +G(2d,p) level of theory. The Conductor Polarized Continuum Model (CPCM) was used to evaluate the solvent effects on the relative stabilities of these tautomers. The calculations clearly identify the lowest energy tautomeric form for xanthine and lumazine. On the other hand, there appear to be three tautomers for 2-oxo-6-methylpurine, with only minor energetic differences in vacuo. In water, however, only one of them predominates. The lowest energy tautomers presumably represent the predominant tautomeric forms at the molybdenum center of xanthine oxidase during catalysis. Implications of these computational results are discussed in the context of enzyme catalysis.

Catalysis↗
PubMed2001

System, environmental, and policy changes: using the social-ecological model as a framework for evaluating nutrition education and social marketing programs with low-income audiences.

A variety of nutrition education interventions and social marketing initiatives are being used by the Food Stamp Program to improve food resource management, food safety, dietary quality, and food security for low-income households. The Social-Ecological Model is proposed as a theory-based framework to characterize the nature and results of interventions conducted through large public/private partnerships with the Food Stamp Program. In particular, this article suggests indicators and measures that lend themselves to the pooling of data across counties and states, with special emphasis on systems, environment, and public policy change within organizations at the community and state levels.

Food Services↗
PubMed2001

Increased hepatic oxidative DNA damage in patients with hepatocellular carcinoma.

Since oxidative DNA damage plays a role in experimental carcinogen-induced cancers, the purpose of the present study was to determine if hepatic oxidative DNA damage was increased in patients with HCC compared to patients with benign hepatic tumors or hepatic metastases (non-HCC) or to patients with end-stage alcoholic liver disease undergoing liver transplantation. Oxidative DNA damage was assessed by 8-hydroxy-2'-deoxyguanosine (8-OH-dG). Results showed that peritumoral 8-OH-dG was markedly increased in HCC (N= 51) (180 +/- 74 vs 32 +/- 58-OH-dG/10(6)dG for tumor, P < 0.005) in contrast to patients with non-HCC (N = 17), in whom the peritumoral 8-OH-dG did not differ from that in tumor (39 +/- 7 vs. 31 +/- 108-OH-dG/10(6)dG). Oxidative DNA damage can be both mutagenic and carcinogenic; our data suggested it will be important in future studies to determine the chronology of this type of liver injury relative to hepatocarcinogenesis.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2001

Percutaneous retrograde varicocele embolisation using tungsten embolisation coils: a five year audit.

OBJECTIVE: To assess the efficacy of percutaneous retrograde varicocele embolisation using Spirale tungsten coils over a period of five years. PATIENTS AND METHODS: Fifty consecutive patients underwent local anaesthetic day case varicocele embolisation via a right femoral approach. Venous anatomy was identified and classified. Morbidity and recurrence were recorded at three month clinical follow up. RESULTS: The procedurewas technically successful in 94% of the patients. The varicocele recurred in 16%, the majority of whom had complex venous anatomy. 8% of the patients complained of discomfort at follow up. CONCLUSIONS: Although the coils used in this study have been withdrawn, a high technical success rate is described with failure being predominantly due to complex venous anatomy.

Adolescent↗
PubMed2001

Desmosomal adhesion regulates epithelial morphogenesis and cell positioning.

Desmosomes are intercellular junctions of epithelia and are of widespread importance in the maintenance of tissue architecture. We provide evidence that desmosomal adhesion has a function in epithelial morphogenesis and cell-type-specific positioning. Blocking peptides corresponding to the cell adhesion recognition (CAR) sites of desmosomal cadherins block alveolar morphogenesis by epithelial cells from mammary lumen. Desmosomal CAR-site peptides also disrupt positional sorting of luminal and myoepithelial cells in aggregates formed by the reassociation of isolated cells. We demonstrate that desmosomal cadherins and E-cadherin are comparably involved in epithelial morphoregulation. The results indicate a wider role for desmosomal adhesion in morphogenesis than has previously been considered.

Animals↗
PubMed2001

Size constraints for targeting post-transcriptional gene silencing and for RNA-directed methylation in Nicotiana benthamiana using a potato virus X vector.

Using a recombinant potato virus X (PVX) vector, we investigated the relationship between the length of RNA sequence identity with a transgene and the ability to promote post-transcriptional gene silencing (PTGS) and transgene methylation. The lower size limit required for targeting reporter transgene mRNA de novo using PTGS was 23 nucleotides (nt) of complete identity, a size corresponding to that of small RNAs associated with PTGS in plants and RNA interference (RNAi) in animals. The size and sequence specificity were also explored for PTGS-associated transgene methylation and for the targeting of the vector RNA. The PTGS-competent short sequences resulted in similar patterns of methylation. In all cases, including specific sequences of 33 nt with or without symmetrical cytosine residues, the methylation was distributed throughout the transcribed region of the transgene. In contrast, short sequences lacking symmetrical cytosines were less efficient at promoting PTGS of the transgene mRNA. Short gfp sequences in the PVX vector provided as effective a target for the degradation of viral RNA as was found for PVX carrying the complete gfp cDNA. Short sequences were able to initiate PTGS of an endogenous gene, phyotene desaturase, although this occurred in the absence of DNA methylation. This experimental approach provides important insights into the relationship between short RNA sequences and PTGS.

DNA Methylation↗
PubMed2001

Cloning and characterization of irregular xylem4 (irx4): a severely lignin-deficient mutant of Arabidopsis.

A severe lignin mutant, irx4, has been identified in Arabidopsis thaliana as a result of its collapsed xylem phenotype. In contrast to previously described irx mutants, irx4 plants have 50% less lignin than wild-type plants, whilst the cellulose and hemicellulose content remained unchanged. These alterations in the composition of irx4 secondary cell walls had a dramatic effect on the morphology and architecture of the walls, which expand to fill most of the cell, and also on the physical properties of irx4 stems. Further analysis indicated that the irx4 mutation occurred in a cinnamoyl-CoA reductase (CCR) gene within a highly conserved intron splice site sequence of intron 2. As a result, CCR mRNA transcripts were incorrectly spliced. Transgenic plants expressing an IRX3 promoter-CCR cDNA construct were used to generate a series of plants with varying degrees of lignin content in order to assess the role of lignin content in determining the physical properties of Arabidopsis stems.

Aldehyde Oxidoreductases↗
PubMed2001

Food and nutritional care in hospitals: how to prevent undernutrition--report and guidelines from the Council of Europe.

In 1999 the Council of Europe decided to collect information regarding Nutrition programmes in hospitals and for this purpose a network consisting of national experts from eight of the Partial Agreement member states was established. The aim was to review the current practice in Europe regarding hospital food provision, to highlight deficiencies and to issue guidelines to improve the nutritional care and support of hospitalized patients. Five major problems seemed to be common in this context: 1) lack of clearly defined responsibilities; 2) lack of sufficient education; 3) lack of influence of the patients; 4) lack of co-operation among all staff groups; and 5) lack of involvement from the hospital management. To solve the problems highlighted, a combined 'team-effort' is needed from national authorities and all staff involved in the nutritional care and support, including hospital managers.

Europe↗
PubMed2001

The pituitary response to ovine corticotropin-releasing hormone is enhanced in obese men and correlates with insulin resistance.

Hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis in central obesity has been demonstrated in women. We studied the corticotropin (ACTH) and cortisol response to ovine corticotropin releasing hormone (oCRH) and its association to parameters of adiposity and insulin resistance in a group of 19 healthy obese (BMI > 25 kg/m2) and 9 non-obese men. Relative insulin resistance was assessed by the homeostatic model assessment (HOMA IR). Baseline ACTH was similar, while cortisol was lower in the obese group. The ACTH response to oCRH was significantly higher in the obese group. ACTH incremental area under the curve (iAUC) correlated with age, HOMA IR, and sagittal diameter but not with leptin. In multiple regression analysis, only HOMA IR was an independent predictor of ACTH iAUC. In conclusion, obese men have hyperactivity of the HPA axis at the pituitary level, which appears to be linked to insulin resistance.

Adrenocorticotropic Hormone↗
PubMed2001

The ex vivo wettability of soft contact lenses.

PURPOSE: To investigate the ex vivo wettability of Etafilcon A contact lenses over an eight hour period of wear and observe the influence of surfactant pre-treatment. METHODS: Etafilcon A hydrogel lenses, comprising poly[2-hydroxyethyl methacrylate-co-methacrylic acid] and 58% water, were soaked for 12 hours in either 0.9% saline (control) or a 1% aqueous solution of poloxamine 1107 (treated). The advancing and receding contact angles were subsequently determined ex vivo after various periods of wear in six adapted contact lens wearers using a single-blind, randomised protocol. Contact angles were measured with a dynamic contact angle tensiometer, using the Wilhelmy plate technique. Patient comfort scores were recorded and the static surface tensions of the probe fluids assessed. RESULTS: Control lenses exhibited no change in wetting angles over time, indicating a lack of surface modification by components within the tear film. Treated lenses exhibited a significantly reduced advancing angle (p < 0.001) and hysteresis angle (p < 0.001) when compared with control lenses. In addition, treated lenses were consistently rated as being more comfortable than control lenses (p = 0.04). CONCLUSIONS: This study has shown clearly that new Etafilcon A lenses do not exhibit significant changes in wettability during the initial four hour wearing period. Pre-treatment of such lenses with a polymeric surfactant results in wetting of the lenses due to the adsorption of surfactant. The surfactant is retained by the lens for at least eight hours of wear, resulting in significant improvements in subjective comfort, especially over the first 30 minutes of wear.

Adolescent↗
PubMed2001

Instant vertebral assessment: a noninvasive dual X-ray absorptiometry technique to avoid misclassification and clinical mismanagement of osteoporosis.

The presence of a vertebral fracture significantly increases the risk of future fracture, classifies a patient with "clinical" osteoporosis, and usually results in treatment for osteoporosis. However, the majority of vertebral fractures are silent, and lateral X-rays (the standard method for identification) are not routinely obtained. Instant vertebral assessment (IVA), a technology that utilizes dual X-ray absorptiometry (DXA), provides rapid assessment of vertebral fractures and is highly correlated with vertebral fractures, as assessed on standard lateral spine X-rays. To assess the role of IVA in patient management, we examined standard bone mineral density (BMD) of the spine, total hip, and femoral neck and spine IVA by DXA in 482 participants screened for an osteoporosis study, who had no previous knowledge of vertebral fractures. Using World Health Organization (WHO) guidelines, subjects were classified using BMD at the spine, total hip, femoral neck, or any combination of these central sites. In addition, we considered subjects as osteoporotic if they had vertebral fractures independent of low bone density. We found that vertebral fractures assessed by IVA were present in 18.3% of asymptomatic postmenopausal women recruited for this study. The sensitivity of BMD alone to diagnose osteoporosis based on either a vertebral fracture or low BMD using WHO criteria ranged from 40 to 74%. This means that between 26 and 60% of osteoporotic individuals could have potentially been missed. Furthermore, 11.0-18.7% of clinically osteoporotic individuals would have been classified as normal by BMD criteria alone. We conclude that IVA is a useful adjunct in the clinical identification of osteoporosis and may prevent mismanagement of osteoporotic patients.

Absorptiometry, Photon↗
PubMed2001

Molecular analysis of the genomic inversion and insertion of AF10 into MLL suggests a single-step event.

The interstitial insertion of genetic material from one chromosome into another can achieve the type of gene-gene fusions more usually associated with chromosome translocations. An example of such an interstitial insertion, which has created an MLL-AF10 fusion in an acute myeloid leukaemia, has been analysed at the genomic level. The genomic fusion, which resulted in the juxtaposition of 3' AF10 sequence to 5' MLL sequence, was identified within MLL and AF10 intronic sequences. It was further established that the remaining 3' MLL sequence, from exon 6 onwards, was fused to novel sequence of unknown origin (named FM3 for fused to MLL 3'). The points of fusion of these 5' and 3' portions of MLL matched to adjacent nucleotides and lay between exons 5 and 6. The FM3 sequence was shown to be from chromosome arm 10p and located close to AF10 in a proximal position. It was subsequently demonstrated that in the leukaemia a third fusion existed between 5' AF10 and the FM3 sequence at a point immediately downstream from its fusion to MLL. It was therefore concluded that the MLL-AF10 gene fusion is the result of a simultaneous transposition of genetic material into the MLL gene and the joining of the remaining free ends on chromosome 10. This kind of event, characterised completely here for the first time, is a means to achieve a fusion when the genes involved lie in opposite orientations and results in three genomic junctions.

Adult↗
PubMed2001

URI and antibiotics.

Explore the source record for details and available documents.

Anti-Bacterial Agents↗
PubMed2001

Mutations of the secondary cell wall.

It has not been possible to isolate a number of crucial enzymes involved in plant cell wall synthesis. Recent progress in identifying some of these steps has been overcome by the isolation of mutants defective in various aspects of cell wall synthesis and the use of these mutants to identify the corresponding genes. Secondary cell walls offer numerous advantages for genetic analysis of plant cell walls. It is possible to recover very severe mutants since the plants remain viable. In addition, although variation in secondary cell wall composition occurs between different species and between different cell types, the composition of the walls is relatively simple compared to primary cell walls. Despite these advantages, relatively few secondary cell wall mutations have been described to date. The only secondary cell wall mutations characterised to date, in which the basis of the abnormality is known, have defects in either the control of secondary cell wall deposition or secondary cell wall cellulose or lignin biosynthesis. These mutants have, however, provided essential information on secondary cell wall biosynthesis.

Arabidopsis↗