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Biomedical subjects

J Lyon

Publications and source records attributed to J Lyon.

At least 19 recordsLinked to original sources
PubMed2001

CORD9 a new locus for arCRD: mapping to 8p11, estimation of frequency, evaluation of a candidate gene.

PURPOSE: To determine the locus of the mutant gene causing autosomal recessive cone-rod dystrophy (arCRD) in a consanguineous pedigree, to evaluate a candidate gene expressed in retina that maps to this locus, and to estimate the percentage of arCRD cases caused by mutations in this gene. METHODS: DNAs from family members were genotyped for markers covering the entire genome at an average spacing of approximately 9 centimorgans (cM). The data were input into a pedigree computer program to produce output files used to calculate lod scores. Significant linkage was revealed at 8cen, prompting the genotyping of a number of additional markers. Exons of a candidate gene were sequenced directly by standard fluorescent dideoxy methods. Haplotype analysis was performed with markers in this locus in 13 multiplex and 2 simplex CRD families in which neither parent had disease. RESULTS: Four-point linkage analysis gave a maximum lod score of approximately 7.6 at both D8S1769 and GATA101H09 in the large consanguineous family. Recombination events defined an interval of 8.7 cM between D8S1820 and D8S532 within which the gene must lie. This 8p11 locus (CORD9) is immediately distal to but distinct from the RP1 autosomal dominant RP (adRP) locus. Two islands of homozygosity were found in this locus: The alleles of 6 of 10 markers in one of the islands and 2 of 4 in the other were homozygous. The UniGene cluster Hs.8719 (UniGene System, provided by the National Center for Biotechnology Information and available at http://www.ncbi.nlm.nih.gov/UniGene), which tags a gene with significant homology to Dual Specificity Phosphatase 3, maps within the CORD9 interval and is highly expressed in the retina. To evaluate this gene as a potential disease candidate, intron-exon structure was determined, and exons were screened in the consanguineous family. No variants were found that could be related to disease. Haplotype analysis of 15 other families with CRD, using markers at CORD9, excluded this locus in 9 of 15. CONCLUSIONS: A new arCRD locus (CORD9) has been identified corresponding to a yet unidentified gene in the 8.7-cM interval D8S1820-D8S532. No mutations were found in one candidate gene in affected members of the primary study family. Haplotype analysis of a cohort of 13 multiplex and 2 simplex families with CRD ruled out the CORD9 gene in 9 of 15 of the families. To date, a total of 126 loci carrying gene mutations causing various forms of retinal degeneration have been mapped, and the mutant gene has been identified in 64 of them. However, only 2 loci for arCRD have been documented. This is the report of a third.

Chromosome Mapping↗
PubMed2000

Cross-sectionally derived hysterectomy prevalence for correcting uterine and ovarian cancer incidence rates and probabilities.

PURPOSE: This paper presents a cross-sectional method for deriving age-specific hysterectomy prevalence. The influence of hysterectomy prevalence on uterine and ovarian cancer incidence rates and probabilities is illustrated.METHODS: Hysterectomy prevalence estimates are derived from cross-sectional data using a life table method. Analysis is based on hysterectomy data from the Utah Hospital Discharge Data Base and cancer cases recorded by the Utah Cancer Registry, 1995-1997.RESULTS: Correction for hysterectomy prevalence increases cancer incidence rates, more so at older ages, such that by ages 85 and older the increase is 92% for uterine cancers of the cervix and corpus, and 17% for ovarian cancer. Over the life span, correction for hysterectomy prevalence increases the estimated number per 100,000 developing these diseases by 195 (from 603 to 798) for uterine cervical cancer, 1,553 (from 2,580 to 4,133) for corpus uterine cancer, and 911 (1,674 to 2,585) for ovarian cancer.CONCLUSIONS: The utility of the cross-sectional method for deriving hysterectomy prevalence is that it does not require several years of data to obtain reasonable estimates. Correction for hysterectomy prevalence has a large effect on the cancer rates and probabilities, providing a more accurate representation of the risk and burden of these cancers.

Journal Article↗
PubMed1999

A novel cofactor for p300 that regulates the p53 response.

The ability of p53 to function as a transcription factor is instrumental in facilitating the response to cellular stress, and p300/CBP proteins, which act as coactivators for diverse transcription factors, participate in regulating p53 activity. We report a novel cofactor for p300 that facilitates the p53 response by augmenting p53-dependent transcription and apoptosis. JMY and p300 associate in physiological conditions, and, during the cellular stress response, the p300/JMY complex is recruited to activated p53. The bax gene is efficiently activated by JMY, and protein isoforms that arise through alternative splicing alter the functional outcome of the p53 response. The results provide compelling evidence that the p300/JMY coactivator complex plays a central role in facilitating the p53 response.

Apoptosis↗
PubMed1999

In charge but not in control: the management of teaching relationships by adults with low perceived power.

The paradoxical use of punitive force by adults with low perceived power was explored in teaching interactions. Punitive force was measured by the intensity of physical effort used in operating controls that displayed negative feedback to child trainees. Women who differed in perceived power were assigned to (a) situations in which they had high, low, or ambiguous control and (b) responsive, unresponsive, or ambiguously responsive children. Women with low perceived power--when given ambiguous control--were more likely than other women to (a) use high levels of punitive force and (b) show elevated levels of autonomic arousal. Arousal, in turn, partially mediated the relationship between perceived power and use of force. Women with low perceived power were also more likely to attribute intentionality to children whose behavior was ambiguous. Results were interpreted as having implications for violence within adult-child relationships.

Adult↗
PubMed1998

Characterization of exon skipping mutants of the COP1 gene from Arabidopsis.

The removal of introns from pre-mRNA requires accurate recognition and selection of the intron splice sites. Mutations which alter splice site selection and which lead to skipping of specific exons are indicative of intron/exon recognition mechanisms involving an exon definition process. In this paper, three independent mutants to the COP1 gene in Arabidopsis which show exon skipping were identified and the mutations which alter the normal splicing pattern were characterized. The mutation in cop1-1 was a G-->A change 4 nt upstream from the 3' splice site of intron 5, while the mutation in cop1-2 was a G-->A at the first nucleotide of intron 6, abolishing the conserved G within the 5' splice site consensus. The effect of these mutations was skipping of exon 6. The mutation in cop1-8 was G-->A in the final nucleotide of intron 10 abolishing the conserved G within the 3' splice site consensus and leading to skipping of exon 11. The splicing patterns surrounding exons 6 and 11 of COP1 in these three mutant lines of Arabidopsis provide evidence for exon definition mechanisms operating in plant splicing.

Arabidopsis↗
PubMed1995

Nucleated erythrocyte count in newborn infants with left-sided congenital diaphragmatic hernia: relationship with the need for extracorporeal membrane oxygenation and survival.

Inadequate cardiac output in fetuses with left-sided congenital diaphragmatic hernia may cause chronic hypoxia and increased erythropoiesis. Postnatal nucleated erythrocyte counts were measured in 28 newborn infants with left-sided congenital diaphragmatic hernia who were eligible for extracorporeal membrane oxygenation (ECMO). Nucleated erythrocyte counts were lowest in infants who survived without ECMO, intermediate in survivors requiring ECMO, and highest in infants who died despite ECMO.

Analysis of Variance↗
PubMed1994

Effects of probenecid on the pharmacokinetics and pharmacodynamics of adinazolam in humans.

The effects of probenecid (2 gm) on the pharmacokinetics, pharmacodynamics, and uricosuric effects of adinazolam and N-desmethyladinazolam were assessed after single dose administration of adinazolam mesylate sustained-release tablets (60 mg) in a randomized, four-way crossover, double-blind study involving 16 healthy male volunteers. Probenecid decreased adinazolam oral clearance, renal N-desmethyladinazolam clearance, and the amount of N-desmethyladinazolam excreted in the urine. Probenecid increased the N-desmethyladinazolam/adinazolam AUC ratio, adinazolam maximum concentration (Cmax), N-desmethyladinazolam Cmax, and N-desmethyladinazolam time to reach Cmax. Uric acid renal clearance was increased significantly by adinazolam or probenecid administration compared with placebo; however, coadministration of adinazolam plus probenecid had no additive effect on uric acid clearance. Psychomotor performance was decreased in the adinazolam plus probenecid treatment compared with the adinazolam treatment. Probenecid potentiated the psychomotor effects of adinazolam after coadministration of the compounds, predominantly because of alterations in N-desmethyladinazolam pharmacokinetics. Therefore the adinazolam dose may need to be reduced when coadministered with probenecid.

Administration, Oral↗
PubMed1994

The role of Myb proteins in normal and neoplastic cell proliferation.

The c-myb protooncogene is the prototype of a gene family that contains two other recently described members, A-myb and B-myb. The c-myb gene encodes a transcription regulatory protein, c-Myb, that has distinct DNA-binding domain structure and binding specificity compared with unrelated transcription factors. All three members of the myb protein family, however, display a high degree of homology within their DNA-binding domain, suggesting that they may regulate transcription of a similar set of target genes. We examine here whether, by implication, the individual members of the myb gene family play analogous roles within the cell, in particular focusing on their potential functions in the control of cell proliferation. Expression of both c-myb and B-myb is subject to regulation in the cell cycle, transcripts of these genes being induced within the G1 phase of the cell cycle and persisting at maximal levels through S phase. Consistent with this timing of expression, inhibition of c-Myb and B-Myb synthesis by treatment of cells with anti-sense oligonucleotides indicates that both proteins are required for transition from the G1 to S phase of the cell cycle. The c-Myb and B-Myb proteins cannot be considered as analogs, however, as they show certain differences in trans-activation activity of their target genes. Moreover, while superficially similar, expression of c-myb and B-myb is not coordinated, and it is conceivable that their products have quite distinct functions in the regulation of cell proliferation. The ubiquitous expression of B-myb in cycling cells and its strict regulation during late G1 suggest a universal function for B-Myb in G1 to S phase transition. Consistent with this conclusion, B-myb transcription is controlled by the transcription factor E2F, which has been implicated in cell cycle regulation of a number of genes involved in DNA synthesis. The restricted tissue tropism of c-myb expression and its regulation by certain growth factors such as IL-2 suggest a specific function in transduction of extrinsic proliferation (and differentiation) signals. The role of A-myb in the cell remains to be determined; however, its expression shows no correlation with cell cycling, implying that it has no direct role in cell proliferation. Recent data show that the necessity for c-myb function in proliferation of a number of cell types provides a promising opportunity for intervention in the treatment of certain tumors.

Animals↗
PubMed1994

A diabetic day in the outback.

Isolated communities present particular problems for patients with chronic conditions. This article studies information gained from a 'diabetic day' held in our community, the aim of which was to assess our present standard of care and to provide our diabetic community with much easier access to specialised health care workers.

Administration, Oral↗
PubMed1994

Management of upper respiratory tract infections by telephone.

We surveyed Utah general internists (N = 134) regarding their attitudes toward and practices associated with telephone management of upper respiratory tract infections. The questionnaire contained 3 case vignettes--viral upper respiratory tract infection, streptococcal pharyngitis, and acute infectious epiglottitis--and a series of questions were asked about telephone diagnosis, management preferences (clinic versus telephone), and telephone management practices. The 53 respondents (40%) were able to make important diagnostic distinctions about upper respiratory tract infections from a written vignette. As the likelihood of a complicated or serious condition increased, patients would be appropriately triaged for clinical evaluation. Most internists would make a written record of the telephone conversation. Only 1 internist of the 53 would charge for telephone management.

Acute Disease↗
PubMed1993

Social cognitions as organizers of autonomic and affective responses to social challenge.

Autonomic and affective responses to children were assessed as a function of adult perceptions of interpersonal control. Women (N = 160) interacted with and provided feedback to computer-simulated children who "behaved" responsively or unresponsively on a computer game. Women were categorized as low in perceived control (PC) if they attributed high control to children but low control to self over negative events on the Parent Attribution Test. As predicted, low-PC women were maximally reactive to child characteristics, manifesting peak levels of defensive arousal (increased level of heart rate and electrodermal activity) and negative affect with unresponsive children and minimal levels of arousal and negative affect with responsive children. Intermediate response levels were shown by high-PC Ss. We interpreted results as suggesting mediating factors that may operate in dysfunctional interaction patterns previously found for low-PC caregivers.

Adult↗
PubMed1993

Detection of antisense transcripts in transgenic plants by RT-PCR.

A reverse transcriptase-polymerase chain reaction (RT-PCR) where one oligonucleotide primer is end-labelled has been used to analyse expression in transgenic plants carrying antisense gene constructs. Specific detection of both sense and antisense RNA transcripts of the spliceosomal protein gene, U2B'', was achieved using the same pair of oligonucleotide primers. To maintain specificity, a reaction step in which reverse transcriptase was inactivated and RNA digested was found to be essential.

Base Sequence↗