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Biomedical subjects

N Carey

Publications and source records attributed to N Carey.

At least 37 records · Page 2Linked to original sources
PubMed1996

Tools to incorporate some psychological and organizational issues during the development of computer-based systems.

The organization, findings and outcomes of a joint industrial/academic project are described. The principal goal of the project was to develop and test some tools through which people involved in system development can incorporate explicit consideration of certain key psychological and organizational issues. Five tools developed for this purpose are outlined. These are concerned with the design of work organization, job design, the allocation of tasks between humans and computers, usability and task analysis. The use of the tools is described in a 'live' system development project in a large company. The authors briefly review the extent to which these tools meet a set of pre-specified requirements, compare their approach with those of Mumford (1986) and Lim et al. (1992), and make explicit what claims they are making of these tools.

Computer Systems↗
PubMed1995

A novel homeodomain-encoding gene is associated with a large CpG island interrupted by the myotonic dystrophy unstable (CTG)n repeat.

Myotonic dystrophy (DM) is associated with a (CTG)n trinucleotide repeat expansion in the 3'-untranslated region of a protein kinase-encoding gene, DMPK, which maps to chromosome 19q13.3. Characterisation of the expression of this gene in patient tissues has thus far generated conflicting data on alterations in the steady state levels of DMPK mRNA, and on the final DMPK protein levels in the presence of the expansion. The DM region of chromosome 19 is gene rich, and it is possible that the repeat expansion may lead to dysfunction of a number of transcription units in the vicinity, perhaps as a consequence of chromatin disruption. We have searched for genes associated with a CpG island at the 3' end of DMPK. Sequencing of this region shows that the island extends over 3.5 kb and is interrupted by the (CTG)n repeat. Comparison of genomic sequences downstream (centromeric) of the repeat in human and mouse identified regions of significant homology. These correspond to exons of a gene predicted to encode a homeodomain protein. RT-PCR analysis shows that this gene, which we have called DM locus-associated homeodomain protein (DMAHP), is expressed in a number of human tissues, including skeletal muscle, heart and brain.

Amino Acid Sequence↗
PubMed1995

Comparison of CTG repeat length expansion and clinical progression of myotonic dystrophy over a five year period.

Myotonic dystrophy (DM) is associated with an underlying CTG trinucleotide repeat expansion at a locus on chromosome 19q13.3. We have determined the repeat length in 23 DM patients with varying clinical severity of symptoms and various sizes of repeat amplification. We confirm that as in previous studies there is no strong correlation between repeat length and clinical symptoms but find that the repeat length in peripheral blood cells of patients increases over a time span of five years indicating continuing mitotic instability of the repeat throughout life. Repeat length progression does not appear to be indicative of clinical progression but age probably is. The degree of expansion correlates with the initial repeat size and 50% of the patients with continuing expansions showed clinical progression of their disease symptoms over the five year study period.

Adolescent↗
PubMed1995

Direct molecular analysis of myotonic dystrophy in the German population: important considerations in genetic counselling.

Myotonic dystrophy (DM) is associated with the expansion and instability of a trinucleotide (CTG) repeat at the DM locus on chromosome 19. Direct genomic analysis in the German population was carried out on 18 DM families, six families with equivocal diagnosis, 69 subjects with equivocal clinical diagnosis, and 100 controls using the polymerase chain reaction (PCR) and a refined Southern protocol. In the majority of the cases molecular analysis confirmed the clinical diagnosis. These included seven cases of congenital DM (CDM) with widely differing gene expansions and instabilities. In most DM families the expanded fragment became larger in successive generations, but we also identified four families with contractions and two families that showed stability of the enlarged fragment during transmission. In four clinically defined DM patients we were unable to detect enlarged CTG repeats. Sequencing of each exon of the DM gene in two of these patients failed to show any mutations. Our cases have important implications for genetic counselling of DM families, highlighting both the diagnostic value of direct genomic analysis and its limitations.

Adult↗
PubMed1994

Sequence variation in the gp135 gene of Maedi visna virus strain EV1.

We have used the PCR and HIRT DNA obtained from MVV-infected tissue culture cells as a template to generate a number of independently derived clones representing overlapping fragments of the gp135 region (env) of Maedi visna virus (MVV) strain EV1. Sequencing these clones revealed that homology between selected regions of gp135 ranged from 93.2% to 99.8%. Four hypervariable regions and one large highly conserved region have been identified. These data provide information on the variability of EV1 env, which extends and complements the data previously available on env variability between geographically distinct isolates of MVV.

Amino Acid Sequence↗
PubMed1994

Myotonic disorders and periodic paralysis.

The myotonias are a diverse set of diseases, variable in presentation, often difficult to diagnose and, until now, treated with only a limited degree of success. Recent genetic advances have pinpointed many of the mutations that underlie these disorders and have demonstrated that there may be different causative genetic mutations underlying the same phenotype. This chapter summarizes the genetic data currently available for these disorders and attempts to link these to their clinical features. In some instances this is conceptually relatively straightforward but in others, particularly DM, the manner in which the mutation leads to the observed phenotype is very unclear and can be used as a paradigm for some of the more puzzling aspects of modern human genetics. Some suggestions are put forward on how the unusual mutation seen in DM can lead to highly variable symptoms between individual patients, and how the mutation can be transmitted unstably through a pedigree.

Humans↗
PubMed1993

Use of recombinant gp135 to study epitope-specific antibody responses to maedi visna virus.

The envelope glycoprotein gp135 of the ovine lentivirus maedi visna virus (MVV) is the main target for neutralising antibody in vivo, however little is known about the specific regions of gp135 which elicit this neutralising response. We have used the polymerase chain reaction (PCR) to generate overlapping fragments of the gp135 gene which have been expressed as fusion proteins in the yeast Ty-VLP system. These fusion proteins have been used to analyse the antibody response to gp135 in MVV infected sheep and we are able to identify at least three distinct regions of gp135 to which antibodies are directed. The approach described in this paper provides a rapid and simple method of generating overlapping fusion proteins with which to carry out epitope mapping studies.

Animals↗
PubMed1993

The detection of problem analytes in a single proficiency test challenge in the absence of the Health Care Financing Administration rule violations.

The Clinical Laboratory Improvement Act of 1988 (CLIA 88) has dramatically changed proficiency testing (PT) practices having mandated (1) satisfactory PT for certain analytes as a condition of laboratory operation, (2) fixed PT limits for many of these "regulated" analytes, and (3) an increased number of PT specimens (n = 5) for each testing cycle. For many of these analytes, the fixed limits are much broader than the previously employed Standard Deviation Index (SDI) criteria. Paradoxically, there may be less incentive to identify and evaluate analytically significant outliers to improve the analytical process. Previously described "control rules" to evaluate these PT results are unworkable as they consider only two or three results. We used Monte Carlo simulations of Kodak Ektachem analyzers participating in PT to determine optimal control rules for the identification of PT results that are inconsistent with those from other laboratories using the same methods. The analysis of three representative analytes, potassium, creatine kinase, and iron was simulated with varying intrainstrument and interinstrument standard deviations (si and sg, respectively) obtained from the College of American Pathologists (Northfield, Ill) Quality Assurance Services data and Proficiency Test data, respectively. Analytical errors were simulated in each of the analytes and evaluated in terms of multiples of the interlaboratory SDI. Simple control rules for detecting systematic and random error were evaluated with power function graphs, graphs of probability of error detected vs magnitude of error. Based on the simulation results, we recommend screening all analytes for the occurrence of two or more observations exceeding the same +/- 1 SDI limit. For any analyte satisfying this condition, the mean of the observations should be calculated. For analytes with sg/si ratios between 1.0 and 1.5, a significant systematic error is signaled by the mean exceeding 1.0 SDI. Significant random error is signaled by one observation exceeding the +/- 3-SDI limit or the range of the observations exceeding 4 SDIs. For analytes with higher sg/si, significant systematic or random error is signaled by violation of the screening rule (having at least two observations exceeding the same +/- 1 SDI limit). Random error can also be signaled by one observation exceeding the +/- 1.5-SDI limit or the range of the observations exceeding 3 SDIs. We present a practical approach to the workup of apparent PT errors.

Bias↗
PubMed1991

Making things worse.

Explore the source record for details and available documents.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Do you feel powerless when a patient refuses medication?

1. Because a client legally has the right to refuse medication, the nurse can only recommend, advise, suggest, or urge the patient to comply. Consequently, it is important to understand the nurse's response to patient refusal of medication. 2. Overall, nurses were more apt to identify with indirect indicators than they were to identify words that address the concept directly (control and powerlessness). 3. The most common hazard identified in a medication refusal event was the potential for injury, and the individuals most at risk were the nurse giving the medication and other personnel on the unit. 4. The most prominent nursing response to medication refusal was counseling. Nearly all the nurse subjects believed that the medication refusal event negatively influenced nursing care, the patient/nurse interaction, and patient teaching.

Adult↗
PubMed1982

A candidate reference method for uric acid in serum. II. Interlaboratory testing.

We describe the interlaboratory testing of a candidate Reference Method (Part I) for uric acid in serum. The method is based on the ultrasound spectrophotometric quantitation of uric acid before and after incubation with uricase. A comprehensive investigation involving 12 laboratories was organized to document the transferability, intra- and interlaboratory precision, and general reliability of the candidate Reference Method. The interlaboratory CV with this method was about 2 to 6% for uric acid concentrations ranging from 0.12 to 0.60 mmol/L. The results detailed here demonstrate that the method can be successfully duplicated among different laboratories.

Evaluation Studies as Topic↗
PubMed1980

The construction and characterisation of plasmid vectors suitable for the expression of all DNA phases under the control of the E. coli tryptophan promoter.

A DNA fragment flanked in the E. coli genome by Hinf I sites and containing the E. coli tryptophan promoter-operator and nucleotides specifying the leader sequence and first seven amino acids of trp E, has been cloned in the Hind III site of pBR322 with the aid of Hind III linkers. The Hind III site upstream from the trp promoter in the transcriptional sense was deleted to generate a Hind III cloning vector, designated pWT111, suitable for the expression of cloned DNA sequences as fusion products. Derivatives of this plasmid were constructed, designated pWT121 and pWT131, whose Hind III cloning sites differ with respect to their translation phasing relative to the initiator ATG of the trp E gene. Both pWT121 and pWT131 have a higher copy number per cell than pWT111. The tetracycline genes of all three plasmids are under trp promoter control and could be used to monitor the transcription of foreign genes inserted at the Hind III site of the vectors.

Cloning, Molecular↗
PubMed1980

Complete structure of the hemagglutinin gene from the human influenza A/Victoria/3/75 (H3N2) strain as determined from cloned DNA.

The complete sequence of a hemagglutinin (HA) gene of a recent human influenza A strain, A/Victoria/3/75, is 1768 nucleotides long and contains the information for 567 amino acids. It codes for a signal peptide of 16 amino acids, the HA1 chain of the mature hemagglutinin of 329 amino acids, a connecting region between HA1 and HA2 consisting of a single arginine residue and the HA2 portion of 221 amiino acids. The sequence is compared with the hemagglutinin of two members of other subtypes, the human H2 strain A/Jap/305/57 and the avian Hav1 strain A/FPV/Rostock/34, and with one of the same H3 subtype, A/Memphis/3/72. To align the HA1 chain of different major subtypes several deletions/insertions of single amino acids must be invoked, but two more extensive differences are found at both ends, one leading to an extension of the amino terminal sequence of HA1 and the other (four residues) occurring in the region processed away between HA1 and HA2. Comparison of the HA1 of two H3 strains suggests that drift probably depends on single base mutations, some of which change antigenic determinants. The HA2 region, which apparently is not involved in the immune response, is highly conserved even between different subtypes, and single base substitutions account for all the observed diversity. A hydrophobic segment of 24 residues is present in the same position close to the carboxyl terminus of HA2 in both Victoria and FPV, and presumably functions in implantation into the lipid bilayer. The many conserved features not only in HA2 but also in HA1 suggest a rather rigid architecture for the whole hemagglutinin molecule.

Amino Acid Sequence↗