Search PubMed⌕ Search

Biomedical subjects

L James

Publications and source records attributed to L James.

At least 55 records · Page 3Linked to original sources

Mobilizing positive reinforcement in communities to reduce youth access to tobacco.

A community intervention to mobilize positive reinforcement for not selling tobacco to young people was evaluated. The intervention had five components: (a) mobilization of community support, (b) merchant education, (c) changing consequences to clerks for selling or not selling to those under 18, (d) publicity about clerks' refusals to sell, and (e) feedback to store owners or managers about the extent of their sales to adolescents. A multiple baseline design experiment was conducted, in which two small Oregon communities received the intervention, while two other continued in baseline. Outlets' willingness to sell was assessed repeatedly by teenage volunteers. The intervention significantly reduced the proportion of stores willing to sell. Mobilizing social and material reinforcement for stores not selling tobacco to young people is a viable means of reducing such sales. It may be especially valuable in communities where laws against sales to minors go unenforced.

Adolescent↗

Experimental evaluation of a modular approach to mobilizing antitobacco influences of peers and parents.

The experimental evaluation of two components of a community intervention to prevent adolescent tobacco use are described. Youth antitobacco activities (e.g., peer quizzes, sidewalk art, poster and T-shirt giveaways, etc.) and family communications activities (pamphlets to parents and student quizzes of parents) were evaluated in two time-series experiments, each of which was conducted in two experimental and one control community. Students in Grades 6 and 8 and their parents were assessed in a series of four phone surveys in the first experiment and six phone surveys in the second. Implementation of the youth antitobacco and family communications activities led to significantly greater exposure of young people to antitobacco information. They led to increases in parent and youth knowledge about tobacco use and more negative attitudes toward tobacco. In Experiment 2, youths in intervention communities had significantly lower rated intentions to smoke. The findings suggest the value of a modular approach to community interventions for influencing the social context relevant to the onset of adolescent tobacco use.

Adolescent↗

Standard error and sample size determination for estimation of probabilities based on a test variable.

A method of sample size determination for estimation of probabilities based on a test variable is presented. Applications to estimation of sensitivity and specificity of medical tests are the focus of this research, although the methods can be applied to other areas of study such as engineering reliability. Examples are given for determining sample sizes required for the classification of patients with cutaneous lupus erythematosus based on the incidence of several markers. In this example, the test variable is the number of markers present. The methodology employs a weighted average of model-based and non-model-based estimates of the probability with the weights determined by the closeness to or the confidence in the given model. Formulas and charts required for determining sample size are provided for test variables that can be modeled by the binomial, Poisson, or normal distributions, i.e., for the most commonly encountered distributions for counting events (binomial and Poisson) and for measurements (normal). However, the methods given can be applied to any distribution, including multivariate. Especially when relatively small probabilities (the rare events) are being estimated, the techniques provided assistance in safeguarding against undersampling brought on by unwarranted confidence in a test variable distribution and against oversampling required for high accuracy in non-model-based probability estimators.

Epidemiologic Methods↗

Glycylcyclines bind to the high-affinity tetracycline ribosomal binding site and evade Tet(M)- and Tet(O)-mediated ribosomal protection.

N,N-dimethylglycylamido (DMG) derivatives of 6-demethyl-6-deoxytetracycline and doxycycline bind 5-fold more effectively than tetracycline to the tetracycline high-affinity binding site on the Escherichia coli 70S ribosome, which correlates with a 10-fold increase in potency for inhibition of E. coli cell-free translation. The potencies of DMG-doxycycline and DMG-6-demethyl-6-deoxytetracycline were unaffected by the ribosomal tetracycline resistance factors Tet(M) and Tet(O) in cell-free translation assays and whole-cell bioassays with a conditional Tet(M)-producing E. coli strain.

Anti-Bacterial Agents↗

Family centred outreach for forensic psychiatry clients.

This paper will describe issues arising from a National Mental Health Project funded programme. This programme which is currently operating in Victoria, aims to provide assertive outreach support to the families of clients who have a psychiatric disability with a forensic history, and to the clients themselves. The support offered to families and clients by the Epistle Post Release Service was provided on the basis that patients with a major mental illness are prone to stress-related breakdown. By addressing their needs in a community setting, together with the provision of psychoeducation, emotional support and practical assistance, anxiety levels are diminished in both families and clients with the result that relapse and reoffending rates are reduced.

Community Health Nursing↗

Identification and cloning in yeast artificial chromosomes of a region of elevated loss of heterozygosity on chromosome 1p31.1 in human breast cancer.

We have mapped a region of high loss of heterozygosity in breast cancer to a 2-cM interval between the loci D1S430 and D1S465 on chromosome 1p31.1. This region shows allelic imbalance in around 60% of breast tumors. As part of a strategy to clone the target gene(s) within this interval, we have generated a yeast artificial chromosome contig spanning over 7 Mb. YACs from the CEPH and Zeneca (formerly ICI) libraries have been obtained by screening with PCR-based STSs from the region for both previously identified loci and newly isolated STSs. The YACs have been assembled into a contig by a combination of approaches, including analysis of their STS content, generation of new STSs from the ends of key YACs, and long-range restriction mapping. These YAC clones provide the basis for complete characterization of the region of high loss in breast cancer and for the ultimate identification of the target gene(s).

Base Sequence↗

Identification of soluble and membrane-bound isoforms of the murine flt3 ligand generated by alternative splicing of mRNAs.

We have recently described a novel hematopoietic growth factor, referred to as the flt3 ligand, that stimulates the proliferation of sub-populations of hematopoietic cells that are enriched for stem and progenitor cells. This factor is a transmembrane protein that undergoes proteolytic cleavage to generate a soluble form of the protein. We have isolated additional flt3 ligand isoforms by PCR that contain an extra exon and encode what are predicted to be either a soluble form of the ligand or a longer version of the transmembrane protein. We have also isolated cDNAs from murine T cell libraries that encode an isoform of the flt3 ligand that has an unusual C-terminus. This isoform results from a failure to splice out an intron during mRNA processing. The protein encoded by this cDNA is expressed on the cell surface, where it is biologically active. However, this novel isoform does not appear to give rise to a soluble form of the protein. Regulation of mRNA splicing is likely to control the generation of cell bound or soluble forms of this hematopoietic growth factor. Genetic mapping studies localize the gene encoding the flt3 ligand to the proximal portion of mouse chromosome 7 and to human chromosome 19q13.3.

Alternative Splicing↗

Effect of L-carnitine treatment on very low density lipoprotein kinetics in the hyperlipidemic rabbit.

This study examined the hypolipidemic effect of 4 weeks of L-carnitine treatment (170 mg/kg b.w./day) in New Zealand White rabbits fed a high fat diet (5% corn oil/0.5% cholesterol). Specifically, [3H] glycerol and [125I] very low density lipoprotein (VLDL) turnover studies were conducted to examine the effect of treatment on VLDL kinetics. The masses of plasma VLDL-triglycerides (VLDL-TG) and VLDL-apoprotein B (VLDL-apoB) were significantly increased by the high-fat diet. Four weeks of treatment with L-carnitine significantly reduced these masses. Kinetic analysis indicated that fat feeding reduced the fractional catabolic rates (FCRs) of VLDL-TG and VLDL-apoB relative to chow-fed controls. The transport of these VLDL components was not altered by the diet. L-carnitine treatment had no effect on the FCRs of VLDL-TG and VLDL-apoB or on the transport of VLDL-apoB. Yet, treatment significantly lowered the transport of VLDL-TG. These data indicate that the lipid-lowering effect of L-carnitine in this animal model was due, in part, to a decrease in the transport and not due to an alteration in the fractional catabolic rate of VLDL-TG.

Animals↗

Maintenance of serum albumin levels in pediatric burn patients: a prospective, randomized trial.

A prospective, randomized trial was performed to determine whether maintaining serum albumin levels in burned pediatric patients had any effect on morbidity and mortality. Patients < 19 years of age with burns > 20% total body surface area were randomized to receive supplemental albumin to maintain levels 2.5 to 3.5 g/dL ("High Albumin") or were given albumin only if levels dropped < 1.5 g/dL ("Low Albumin") after completing burn shock resuscitation. The 36 patients in the Low Albumin group were well matched for age, burn size, depth of injury, and inhalation injury when compared with the High Albumin group (34 patients). As expected, serum albumin levels were significantly lower in the Low Albumin group when compared with the High Albumin group. No differences between groups were noted for resuscitation needs, maintenance fluid requirements, urine output, tube feedings received, days of antibiotic treatment, or ventilatory requirements. No differences in hematology, electrolytes, or nutritional laboratories were found. Finally, length of stay, complication rate, and mortality were not affected by albumin treatment. Albumin supplementation to maintain normal serum levels does not seem to be warranted in previously healthy children who suffer severe burns and who receive adequate nutrition.

Adolescent↗

Molecular characterization of a family of ligands for eph-related tyrosine kinase receptors.

A family of tyrosine kinase receptors related to the product of the eph gene has been described recently. One of these receptors, elk, has been shown to be expressed only in brain and testes. Using a direct expression cloning technique, a ligand for the elk receptor has been isolated by screening a human placenta cDNA library with a fusion protein containing the extracellular domain of the receptor. This isolated cDNA encodes a transmembrane protein. While the sequence of the ligand cDNA is unique, it is related to a previously described sequence known as B61. Northern blot analysis of human tissue mRNA showed that the elk ligand's mRNA is 3.5 kb long and is found in placenta, heart, lung, liver, skeletal muscle, kidney and pancreas. Southern blot analysis showed that the gene is highly conserved in a wide variety of species. Both elk ligand and B61 mRNAs are inducible by tumour necrosis factor in human umbilical vein endothelial cells. In addition, both proteins show promiscuity in binding to the elk and the related hek receptors. Since these two ligand sequences are similar, and since elk and hek are members of a larger family of eph-related receptor molecules, we refer to these ligands as LERKs (ligands for eph-related kinases).

Amino Acid Sequence↗

Cloning of the human homologue of the murine flt3 ligand: a growth factor for early hematopoietic progenitor cells.

Using a fragment of the murine flt3 ligand as a probe, we have succeeded in cloning a human flt3 ligand from a human T-cell lambda gt10 cDNA library. The human and murine ligands are 72% identical at the amino acid level. Analysis of multiple cDNA clones shows that alternative splicing of the human flt3 mRNA can occur at a number of positions. A recombinant soluble form of the human flt3 ligand stimulates the proliferation and colony formation of a subpopulation of human bone marrow cells that are CD34+ and are enriched for primitive hematopoietic cells. In addition, the human flt3 ligand also stimulates the proliferation of cells expressing murine flt3 receptors. Northern blot analysis shows widespread expression of flt3 ligand mRNA transcripts in human tissues.

Amino Acid Sequence↗

DNA rearrangements proximal to the EVI1 locus associated with the 3q21q26 syndrome.

Specific rearrangements involving 3q21 and 3q26 are well documented in acute myeloid leukemia (AML). Aberrant expression of the Ecotropic virus integration-1 (EVI1) gene, located at 3q26, has been reported in individuals with AML and translocations or inversions of chromosome 3 long arm. We have studied six individuals with AML and inv(3)(q21q26) for disruptions to the EVI1 locus by in situ hybridization and long-range mapping. EVI1 transcripts have been detected in the blast cells of the two individuals available for expression studies. We derived a YAC containing the EVI1 gene and showed that it crossed the 3q26 inversion breakpoints in three of four cases examined. Pulsed field analysis detected aberrant fragments 3' of the EVI1 gene in all six patients. The orientation of the gene was established and the locations of the breakpoints were refined by in situ hybridization using phage clones from this region.

Base Sequence↗

Randomized trial comparing weekly versus 3-week chemotherapy in small-cell lung cancer: a Cancer Research Campaign trial.

PURPOSE: A randomized trial of chemotherapy, given on either a 1-week or a 3-week schedule, was performed in small-cell lung cancer (SCLC) patients. The aim was to determine if weekly scheduling produced survival superior to conventional treatment. PATIENTS AND METHODS: Four hundred thirty-eight patients with SCLC with either limited disease (LD; 276 patients) or good-prognosis extensive disease (ED; 162 patients) were randomized. Weekly chemotherapy was 12 alternating cycles of ifosfamide/doxorubicin and cis-platin/etoposide (PE), while 3-week treatment was six alternating cycles of cyclophosphamide/doxorubicin/vincristine (CAV) and PE. Thoracic irradiation was administered 3 weeks after completion of chemotherapy to LD patients who attained a complete response (CR) or partial response (PR). Patients were well matched for clinical characteristics and prognostic factors. RESULTS: Overall response was the same in both arms: 82.3% (39.4% CR) with weekly and 81.1% (36.9% CR) with 3-week treatment. The median survival (MS) durations were 10.8 and 10.6 months for weekly and 3-week chemotherapy, respectively. The 2-year survival rates were 11.8% and 11.7% in the weekly and 3-week arms, respectively. Received dose-intensity (DI) was 73.9% of projected for weekly treatment and 92.7% for 3-week treatment. Hematologic toxicity was the major dose-limiting toxicity for the weekly treatment. CONCLUSION: This trial excludes at 90% power a benefit of greater than 10% for 2-year survival for weekly treatment. The received DI was reduced to a greater extent with weekly treatment, mainly due to hematologic toxicity.

Adult↗

LERK-2, a binding protein for the receptor-tyrosine kinase ELK, is evolutionarily conserved and expressed in a developmentally regulated pattern.

We have isolated and characterized cDNA clones that encode the rat homologue of a binding protein, LERK-2, for the receptor tyrosine kinase, elk. The cDNAs contain an open reading frame of 1527 nucleotides capable of encoding a protein 345 amino acid residues in length. The nucleotide sequence of the present clones is > 90% identical to the previously identified human LERK-2 cDNA, and the predicted proteins encoded by the rat and human clones are identical at 95% of amino acid residues. Recombinant proteins expressed from the rat cDNAs bind to elk with high affinity, similar to recombinant human LERK-2 and an endogenously-expressed rat elk-binding protein. Expression of the rat LERK-2 mRNA was detected in embryonic brain, kidney, lung, skeletal muscle, thymus, liver, and heart, and diminished in the early post-natal period. Significant LERK-2 mRNA expression in the young adult rat was restricted to the lung, kidney, heart and testes.

Amino Acid Sequence↗

Molecular cloning of a ligand for the flt3/flk-2 tyrosine kinase receptor: a proliferative factor for primitive hematopoietic cells.

Cloning of a ligand for the murine flt3/flk-2 tyrosine kinase receptor was undertaken using a soluble form of the receptor to identify a source of ligand. A murine T cell line, P7B-0.3A4, was identified that appeared to express a cell surface ligand for this receptor. A cDNA clone was isolated from an expression library prepared from these cells that was capable, when transfected into cells, of conferring binding to a soluble form of the flt3/flk-2 receptor. The cDNA for this ligand encodes a type I transmembrane protein that stimulates the proliferation of cells transfected with the flt3/flk-2 receptor. A soluble form of the ligand stimulates the proliferation of defined subpopulations of murine bone marrow and fetal liver cells as well as human bone marrow cells that are highly enriched for hematopoietic stem cells and primitive uncommitted progenitor cells.

Amino Acid Sequence↗