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Biomedical subjects

A Jones

Publications and source records attributed to A Jones.

At least 235 records · Page 13Linked to original sources
PubMed1999

Functional genomics in Caenorhabditis elegans: An approach involving comparisons of sequences from related nematodes.

Comparative genomic analysis was used to investigate the gene structure of the bli-4 locus from two related Caenorhabditis species, C. elegans and C. briggsae. In C. elegans, bli-4 is a complex gene encoding a member of the kex2/subtilisin-like family of proprotein convertases. Genomic sequence comparisons coupled with RT-PCR analysis identified five additional coding exons that had not been identified previously using standard recombinant DNA techniques. The C. briggsae gene was able to rescue both viable blistered and developmentally arrested mutants of C. elegans bli-4, demonstrating functional conservation. In addition, deletion analysis of conserved sequences outside of coding regions, combined with phenotypic rescue experiments, identified regulatory elements that alter the expression of the bli-4 gene. These results demonstrate the utility of genomic sequence comparisons of homologous genes in related species as an effective tool with which to dissect the functional information of complex genes.

Alternative Splicing↗
PubMed1999

Critical pathways for postoperative care after simple congenital heart surgery.

OBJECTIVE: To evaluate the clinical, financial, and parent/patient satisfaction impact of critical pathways on the postoperative care of pediatric cardiothoracic patients with simple congenital heart lesions. STUDY DESIGN: Critical pathways were developed by pediatric intensive care nurses and implemented under the direction of pediatric cardiothoracic surgeons. PATIENTS AND METHODS: Critical pathways were used during a 12-month study on 46 postoperative patients with simple repair of atrial septal defect (ASD), coarctation of the aorta (CoA), and patent ductus arteriosus (PDA). Using the study criteria, a control group of 58 patients was chosen from 1993. Prospective and control group data collected included postoperative intubation time, total laboratory tests, arterial blood gas utilization, morphine utilization, time in the pediatric intensive care unit, total hospital stay, total hospital charges, total hospital cost, and complications. Variances from the critical pathway and satisfaction data were also recorded for study patients. RESULTS: Resource utilization was reduced after implementation of critical pathways. Significant reductions were seen in total hours in the pediatric intensive care unit, total number of laboratory tests, postoperative intubation times, arterial blood gas utilization, morphine utilization, length of hospitalization (ASD, 4.9 to 3.1 days; CoA, 5.2 to 3.2 days; and PDA, 4.1 to 1.4 days; all P < 0.05), total hospital charges (ASD, $16,633 to $13,627; CoA, $14,292 to $8319; and PDA, $8249 to $4216; all P < 0.05), and total hospital costs. There was no increase in respiratory complications or other complications. Patients and families were generally satisfied with their hospital experience, including analgesia and length of hospitalization. CONCLUSIONS: Implementation of critical pathways reduced resource utilization and costs after repair of three simple congenital heart lesions, without obvious complications or patient dissatisfaction.

Aortic Coarctation↗
PubMed1999

The National Home and Hospice Care Survey: 1996 summary.

OBJECTIVE: This report presents data about agencies providing home and hospice care, their current patients, and their discharges. The data are presented in 159 tables according to standard sets of descriptive variables. The tables are grouped into five categories: agencies, home health care current patients, home health care discharges, hospice care current patients, and hospice care discharges. Data are presented on agency characteristics, demographic characteristics, utilization measures, and health and functional status of current patients and discharges. METHODS: The data used for this report are from the National Center for Health Statistics' 1996 National Home and Hospice Care Survey. This is a sample survey through which data are collected on the use of home health and hospice care agencies in the United States. The data were collected by personal interview using three questionnaires and two sampling lists.

Adolescent↗
PubMed1999

Aspects of motivation of a volunteer AIDS care team program.

The South Carolina AIDS Care Team Program, directed by The Ecumenical AIDS Ministry, a component of the South Carolina Christian Action Council, provides emotional and supportive services to people living with HIV and AIDS. A sample of volunteer care team members participated in five focus groups as part of a process evaluation. Care teams were asked to participate based on years since training (new vs. experienced), race (white vs. African American), and location (urban vs. rural). Volunteers were motivated to become involved in a care team through previous contact with a person with AIDS, a general sense of altruism, and influences from their faith community. Due to the emotionally demanding nature of the work, motivation to remain a volunteer was also examined. It was discovered that a support system, the expression of faith, support of their faith community, and coping with the death of a care partner were essential elements for sustaining care team involvement. The implications of this study are useful to volunteer programs through faith communities to meet the growing need of people living with HIV and AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Would you take blood through a venflon?

One way of saving junior doctors' time and patients' pain is to take blood samples through a venflon immediately after its insertion. This is not, however, universal practise as some believe the results, especially urea and electrolytes, are unreliable. We have surveyed junior doctors in our hospital about this practise and prospectively compared venflon and vein blood samples.

Blood Specimen Collection↗
PubMed1998

Does quality of reports of randomised trials affect estimates of intervention efficacy reported in meta-analyses?

BACKGROUND: Few meta-analyses of randomised trials assess the quality of the studies included. Yet there is increasing evidence that trial quality can affect estimates of intervention efficacy. We investigated whether different methods of quality assessment provide different estimates of intervention efficacy evaluated in randomised controlled trials (RCTs). METHODS: We randomly selected 11 meta-analyses that involved 127 RCTs on the efficacy of interventions used for circulatory and digestive diseases, mental health, and pregnancy and childbirth. We replicated all the meta-analyses using published data from the primary studies. The quality of reporting of all 127 clinical trials was assessed by means of component and scale approaches. To explore the effects of quality on the quantitative results, we examined the effects of different methods of incorporating quality scores (sensitivity analysis and quality weights) on the results of the meta-analyses. FINDINGS: The quality of trials was low. Masked assessments provided significantly higher scores than unmasked assessments (mean 2.74 [SD 1.10] vs 2.55 [1.20]). Low-quality trials (score < or = 2), compared with high-quality trials (score > 2), were associated with an increased estimate of benefit of 34% (ratio of odds ratios [ROR] 0.66 [95% CI 0.52-0.83]). Trials that used inadequate allocation concealment, compared with those that used adequate methods, were also associated with an increased estimate of benefit (37%; ROR=0.63 [0.45-0.88]). The average treatment benefit was 39% (odds ratio [OR] 0.61 [0.57-0.65]) for all trials, 52% (OR 0.48 [0.43-0.54]) for low-quality trials, and 29% (OR 0.71 [0.65-0.77]) for high-quality trials. Use of all the trial scores as quality weights reduced the effects to 35% (OR 0.65 [0.59-0.71]) and resulted in the least statistical heterogeneity. INTERPRETATION: Studies of low methodological quality in which the estimate of quality is incorporated into the meta-analyses can alter the interpretation of the benefit of intervention, whether a scale or component approach is used in the assessment of trial quality.

Bias↗
PubMed1998

Quantification of microbial productivity via multi-angle light scattering and supervised learning.

This article describes the use of chemometric methods for prediction of biological parameters of cell suspensions on the basis of their light scattering profiles. Laser light is directed into a vial or flow cell containing media from the suspension. The intensity of the scattered light is recorded at 18 angles. Supervised learning methods are then used to calibrate a model relating the parameter of interest to the intensity values. Using such models opens up the possibility of estimating the biological properties of fermentor broths extremely rapidly (typically every 4 sec), and, using the flow cell, without user interaction. Our work has demonstrated the usefulness of this approach for estimation of yeast cell counts over a wide range of values (10(5)-10(9) cells mL-1), although it was less successful in predicting cell viability in such suspensions.

Biotechnology↗
PubMed1998

Interleukin (IL)-4-independent induction of immunoglobulin (Ig)E, and perturbation of T cell development in transgenic mice expressing IL-13.

Recent studies using interleukin (IL)-4-deficient animals have highlighted the existence of IL-4-independent immunoglobulin (Ig)E induction. We have established transgenic mice expressing IL-13 from a transgene comprising a genomic fragment containing the IL-13 gene and the human CD2 locus control region. The transgenes were expressed in lymphoid tissues and induced by T cell activators, suggesting regulation by elements of the IL-13 promoter. IL-13 transgenic lines expressed 10-100-fold higher levels of serum IgE than their littermate controls, but had normal levels of other serum Ig isotypes. Elevated IgE levels were also detected in sera from IL-4-deficient mice carrying IL-13 transgenes, indicating that IL-4 is not required for IL-13-induced IgE expression in the mouse. Expression of IL-13 also perturbed the development of thymocytes. Although thymocyte development was normal up to 4 wk of age, thymocyte number decreased dramatically thereafter, reaching 10% of normal by 10 wk, and despite normal size and appearance, histological examination demonstrated that transgenic thymi contained only small foci of thymocytes. The reduction in thymocyte number was due mainly to a depletion of CD4(+)CD8(+) thymocytes, and did not affect significantly the composition of peripheral T cell populations. These data indicate that expression of IL-13 transgenes in vivo can regulate IgE production in the mouse, and that IL-13 may also influence thymocyte development.

Animals↗
PubMed1998

Methodology and reports of systematic reviews and meta-analyses: a comparison of Cochrane reviews with articles published in paper-based journals.

CONTEXT: Review articles are important sources of information to help guide decisions by clinicians, patients, and other decision makers. Ideally, reviews should include strategies to minimize bias and to maximize precision and be reported so explicitly that any interested reader would be able to replicate them. OBJECTIVE: To compare the methodological and reporting aspects of systematic reviews and meta-analyses published by the Cochrane Collaboration with those published in paper-based journals indexed in MEDLINE. DATA SOURCES: The Cochrane Library, issue 2 of 1995, and a search of MEDLINE restricted to 1995. STUDY SELECTION: All 36 completed reviews published in the Cochrane Database of Systematic Reviews and a randomly selected sample of 39 meta-analyses or systematic reviews published in journals indexed by MEDLINE in 1995. DATA EXTRACTION: Number of authors, trials, and patients; trial sources; inclusion and exclusion criteria; language restrictions; primary outcome; trial quality assessment; heterogeneity testing; and effect estimates. Updating by 1997 was evaluated. RESULTS: Reviews found in MEDLINE included more authors (median, 3 vs 2; P<.001), more trials (median, 13.5 vs 5; P<.001), and more patients (median, 1280 vs 528; P<.001) than Cochrane reviews. More Cochrane reviews, however, included a description of the inclusion and exclusion criteria (35/36 vs 18/39; P<.001) and assessed trial quality (36/36 vs 12/39; P<.001). No Cochrane reviews had language restrictions (0/36 vs 7/39; P<.01). There were no differences in sources of trials, heterogeneity testing, or description of effect estimates. By June 1997, 18 of 36 Cochrane reviews had been updated vs 1 of 39 reviews listed in MEDLINE. CONCLUSIONS: Cochrane reviews appear to have greater methodological rigor and are more frequently updated than systematic reviews or meta-analyses published in paper-based journals.

Meta-Analysis as Topic↗
PubMed1998

alpha-conotoxin EpI, a novel sulfated peptide from Conus episcopatus that selectively targets neuronal nicotinic acetylcholine receptors.

We have isolated and characterized alpha-conotoxin EpI, a novel sulfated peptide from the venom of the molluscivorous snail, Conus episcopatus. The peptide was classified as an alpha-conotoxin based on sequence, disulfide connectivity, and pharmacological target. EpI has homology to sequences of previously described alpha-conotoxins, particularly PnIA, PnIB, and ImI. However, EpI differs from previously reported conotoxins in that it has a sulfotyrosine residue, identified by amino acid analysis and mass spectrometry. Native EpI was shown to coelute with synthetic EpI. The peptide sequence is consistent with most, but not all, recognized criteria for predicting tyrosine sulfation sites in proteins and peptides. The activities of synthetic EpI and its unsulfated analogue [Tyr15]EpI were similar. Both peptides caused competitive inhibition of nicotine action on bovine adrenal chromaffin cells (neuronal nicotinic ACh receptors) but had no effect on the rat phrenic nerve-diaphragm (muscle nicotinic ACh receptors). Both EpI and [Tyr15]EpI partly inhibited acetylcholine-evoked currents in isolated parasympathetic neurons of rat intracardiac ganglia. These results indicate that EpI and [Tyr15]EpI selectively inhibit alpha3beta2 and alpha3 beta4 nicotinic acetylcholine receptors.

Amino Acid Sequence↗
PubMed1998

Mouse cerebellar granule cell differentiation: electrical activity regulates the GABAA receptor alpha 6 subunit gene.

GABAA receptor alpha6 subunit gene expression marks cerebellar granule cell maturation. To study this process, we used the Deltaalpha6lacZ mouse line, which has a lacZ reporter inserted into the alpha6 gene. At early stages of postnatal cerebellar development, alpha6-lacZ expression is mosaic; expression starts at postnatal day 5 in lobules 9 and 10, and alpha6-lacZ is switched on inside-out, appearing first in the deepest postmigratory granule cells. We looked for factors regulating this expression in cell culture. Membrane depolarization correlates inversely with alpha6-lacZ expression: granule cells grown in 25 mM [K+]o for 11-15 d do not express the alpha6 gene, whereas cultures grown for the same period in 5 mM [K+]o do. This is influenced by a critical early period: culturing for >/=3 d in 25 mM [K+]o curtails the ability to induce the alpha6 gene on transfer to 5 mM [K+]o. If the cells start in 5 mM [K+]o, however, they still express the alpha6-lacZ gene in 25 mM [K+]o. In contrast to granule cells grown in 5 mM [K+]o, cells cultured in 25 mM [K+]o exhibit no action potentials, mEPSCs, or mIPSCs. In chronic 5 mM [K+]o, factors may therefore be released that induce alpha6. Blockade of ionotropic and metabotropic GABA and glutamate receptors or L-, N-, and P/Q-type Ca2+ channels did not prevent alpha6-lacZ expression, but inhibition of action potentials with tetrodotoxin blocked expression in a subpopulation of cells.

6-Cyano-7-nitroquinoxaline-2,3-dione↗