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D Atkins

Publications and source records attributed to D Atkins.

At least 55 records · Page 3Linked to original sources
PubMed1997

Testing the hypothesis of the multidimensional model of anorexia nervosa in adolescents.

This study statistically tested six hypothesized risk factors of the model for anorexia nervosa. Forty-three adolescents with anorexia nervosa and 85 controls were administered the EAT, EDI, and FES. In addition, 43 parents of anorexics and 85 parents of controls completed the Family History Data Sheet, the FES, and the Perfect Child Questionnaire. Three of six hypothesized risk factors were confirmed: family history of depression, feelings of ineffectiveness, and poor interceptive awareness. Log-linear analysis indicated that the hierarchical model that best fit the data had significant two-way interactions with anorexia nervosa, G2 (11, N = 128) = 65.87, p < .001. In addition, alcohol and drug abuse or dependence figured prominently in the family history of patients with anorexia nervosa. The multidimensional model for anorexia nervosa holds up as an exploratory model of this condition in the adolescent age group.

Adolescent↗
PubMed1997

Lichen planus-like histopathologic characteristics in the cutaneous graft-vs-host reaction. Prognostic significance independent of time course after allogeneic bone marrow transplantation.

BACKGROUND: The discrimination between acute and chronic graft-vs-host disease (GVHD) after allogeneic bone marrow transplantation (BMT) is important because the treatment regimens and prognosis differ. OBJECTIVES: To identify whether accepted histopathologic criteria of a graft-vs-host reaction (GVHR) alone or in combination accurately reflect clinical phase of disease, to correlate patterns with clinical outcome, and to identify any concordance between inflammation and epidermal changes of a GVHR. DESIGN: Skin biopsy specimens were analyzed according to histologically defined standards. SETTING: This study was performed in a tertiary care hospital. PATIENTS: One hundred seventy-three skin biopsy specimens (10 days before to 1326 days after BMT) from 83 patients undergoing allogeneic BMT for various malignant neoplasms were selected for study. A consecutive 12-month sample was used. MAIN OUTCOME MEASURES: The main measures in this study were statistical correlations between histopathologic findings and time after BMT, the outcome of BMT, and the correlations between selected histopathologic criteria. RESULTS: Fully evolved histologic features of chronic lichenoid GVHR in the specimens occurred across a wide time range (33-832 days after BMT) and were associated with a 5.6-fold increased risk for death (P = .02) from GVHD. Histologic features of acute GVHR in the specimens also occurred across a wide time range (14-481 days after BMT) and were associated with a 2.2-fold increased risk for death; this finding was not statistically significant (P = .11). Inflammation of the upper dermis was significantly associated with acanthosis and epidermal cell necrosis (P < .001 and P < .001, respectively, for bandlike pattern), confirming the importance of this finding as a criterion for the diagnosis of a GVHR. Blinded evaluation of a subset of specimens for the diagnosis of acute vs chronic GVHR resulted in wide interobserver variation. CONCLUSIONS: This study demonstrates the following: specific histologic parameters in skin biopsy specimens do not consistently separate acute from chronic GVHD as defined by days after BMT; independent of time course, fully evolved histopathologic characteristics of a lichen planus-like GVHR is associated with a greater likelihood of death from GVHD; and identification of upper dermal inflammation correlates with the epidermal features of GVHR and should be included in the diagnostic scheme.

Acute Disease↗
PubMed1996

Comparison of three 3' non-coding regions in Schizosaccharomyces pombe expression vectors: efficiencies of transcription termination and mRNA 3'-end formation.

Analysis of an established Schizosaccharomyces pombe episomal shuttle vector suggested that inefficient transcription termination was deleterious to plasmid function. We undertook a study to determine if transcription in the presence and absence of 3'-processing within a vector could affect the ability of the plasmid to transform, transcribe and translate the RNA produced. This report provides an analysis of the effects that three S. pombe 3' non-coding regions have on the transformation and expression efficiencies of a fission yeast plasmid vector. The 3' regions from adh1, act1 and ura4 were tested for their ability to terminate and process adh1 promoter-driven transcription of a lacZ reporter gene. Differences between the 3'-processing sequences were observed, with transcription termination mediated by the ura4 3' region being more efficient than termination by the 3' regions of adh1 and act1. We show that plasmids containing inefficient transcription termination signals result in readthrough transcription and reduced transformation efficiencies. In addition, the readthrough transcripts containing 3' non-coding regions show impaired translation efficiencies. We describe an S. pombe vector (pURAS) with a high transformation efficiency that directs the production of highly translatable, discrete-sized transcripts.

Gene Dosage↗
PubMed1996

Developing evidence-based clinical practice guidelines: lessons learned by the US Preventive Services Task Force.

The US Preventive Services Task Force is an expert panel established by the federal government in 1984 to develop evidence-based practice guidelines on screening tests and other preventive services. Its recommendations are published elsewhere. This article explores the lessons learned in the process of developing and disseminating the recommendations. Topics include project organization (analytic philosophy, project sponsorship, panel composition, topic selection); the review of evidence (selecting outcome measures for judging effectiveness, constructing "causal pathways," searching the literature, rating the evidence, synthesizing the results); crafting recommendations (extrapolation, assessing magnitude, balancing risks and benefits, addressing costs, dealing with insufficient data, separating science from policy); peer review; collaboration with other groups; evaluating impact on clinicians' knowledge, attitudes, and behavior; updating recommendations; and defining a research agenda. The lessons learned suggest potential refinements in the future work of the task force and other groups engaged in guideline development.

Diffusion of Innovation↗
PubMed1996

pH sensitivity of Schizosaccharomyces pombe: effect on the cellular phenotype associated with lacZ gene expression.

We report on a series of experiments in Schizosaccharomyces pombe to detect the blue-colour colony phenotype associated with expression of the Escherichia coli lacZ gene. Increasing the pH in solid minimal medium to optimize blue colony colour revealed a pH-sensitive phenotype in auxotrophic strains requiring uracil and leucine as external supplements. This phenotype was observed among common S. pombe stock strains, 5-fluoroorotic acid (5-FOA)selected strains, and random genetic segregants. Growth of prototrophic S. pombe strains 972 and 975 or the adenine auxotrophic strain NCYC 1860 were unaffected by an increase in external pH. Analysis of genetic segregants from three independent crosses indicated that a single auxotrophic marker (ura4- or leu1-32) was sufficient for yeast cell-growth inhibition when the medium pH was increased above 6.6. In contrast, growth of a Saccharomyces cerevisiae strain isogenic to AH22, requiring uracil, leucine and histidine, was unaffected by changes in the pH of the medium. These observations suggest that uptake of uracil and leucine into S. pombe cells is compromised by alterations in external pH. Our results have implications for detection of the lacZ gene-encoded bluecolour colony phenotype in S. pombe, which is optimized by growth in the presence of 5-bromo-4-chloro-3-indolyl- "beta"-D-galactoside (Xgal) at pH 7.0. We discuss the conditions under which this blue-colour phenotype can be routinely observed in S. pombe.

Galactosides↗
PubMed1995

Gene regulation by antisense RNA in the fission yeast Schizosaccharomyces pombe.

This report describes experiments designed to demonstrate the suitability of the fission yeast Schizosaccharomyces pombe as a host for antisense RNA regulation. A lacZ gene-expressing yeast strain was constructed and used as a host for the expression of a series of antisense RNAs complementary to various regions of the target lacZ mRNA. All lacZ antisense genes were placed under control of the thiamine-repressible nmt1 promoter of S. pombe and expressed from episomal plasmids. For each antisense plasmid a corresponding sense control plasmid was constructed. All lacZ antisense genes were shown to express antisense RNAs of the expected size at equivalent steady-state levels. beta-Galactosidase activity in transformed cells expressing the long, short 5' or short 3' lacZ antisense RNAs was shown to be reduced by 45%, 20%, and 10%, respectively, relative to control transformants. Further experiments indicated that antisense RNA regulation in this system was conditional and reversible, with the observed reduction of beta-galactosidase activity being dependent on the transcription of lacZ antisense RNA. Our results represent the first successful example of antisense RNA regulation of gene expression in yeast and establish S. pombe as an experimental model for the biochemical analysis of antisense RNA regulation.

Base Sequence↗
PubMed1995

Expression and analysis of the green fluorescent protein gene in the fission yeast Schizosaccharomyces pombe.

This report demonstrates that the Aequorea victoria green fluorescence protein (gfp) gene product will fluoresce in the fission yeast Schizosaccharomyces pombe when expressed from an episomal expression vector. Fluorescence was readily detectable at both the colony and single cell level. Application of fluorescence-activated cell sorting (FACS) techniques showed that gfp-expressing cells could be detected when they were as rare as 1% of a total yeast population. Quantitative analysis of gfp-expressing cells constituting as little as 5% of a total population was possible. These observations establish the suitability of the gfp gene for use in S. pombe and, in combination with FACS, offers an experimental strategy for quantitative analysis of gene expression in yeast populations.

Base Sequence↗
PubMed1995

[Prolactin producing hypophyseal carcinoma. Case report of an extremely rare metastatic tumor].

A 59-year-old male patient was transnasally operated on because of a pituitary adenoma with hypopituitarism. A second operation and X-ray therapy followed a half year later due to recurrent tumor. Both neoplasmas were classified as sparsely granulated prolactin cell adenomas. Immunohistochemical studies revealed strong immunoreactivity for prolactin and FSH in the tumor cells of both the pituitary adenoma and the recurrent tumor. Two years later the prolactin plasma levels were extremely elevated. A tumor in the liver was identified. Biopsy revealed a solid endocrine tumor containing prolactin by immunohistology. Due to structural and immunohistological similarities this tumor could be identified as a metastasis of the pituitary tumor. After 5 months of therapy the patient died from thrombembolism. Post-mortem studies confirmed the diagnosis of a metastasizing prolactin-secreting pituitary carcinoma. Only six similar cases have been reported in the literature. Our case report confirms the experience with 35 definite pituitary carcinomas reparted in the current literature: malignant pituitary tumors develop after pituitary surgery and can be identified not from the pituitary tumor, but only from its metastases.

Combined Modality Therapy↗
PubMed1995

The ade6 gene of the fission yeast as a target for antisense and ribozyme RNA-mediated suppression.

A genetic system for the analysis of antisense and ribozyme mechanisms is a much needed experimental tool, and yeast represent a favorable organism on which to base such a system. We have shown previously that the fission yeast Schizosaccharomyces pombe has potential to satisfy the requirements of such a system. This report describes experiments designed to determine if antisense and ribozyme RNA-mediated gene suppression will be generally applicable to other genes in S. pombe. Antisense and ribozyme RNAs designed to suppress the ade6 gene were expressed at high levels from episomal expression vectors. The ade6 gene was chosen as a target as mutations within the gene confer adenine auxotrophy and a red colony phenotype, and it was expected that antisense or ribozyme RNA-mediated mutant phenocopies would exhibit the same readily detectable phenotype. No phenotypic indication of ade6 suppression was detected in transformed yeast, and ade6 target mRNA was analyzed by primer extension and Northern analysis. Initially, conflicting results were obtained from these techniques, which were determined to be due to duplex formation between antisense and target RNA in vitro. No detectable reduction in the ade6 mRNA levels was found, and it was concluded that the gene was not suppressed by the antisense or ribozyme RNAs tested. These results confirm that in S. pombe as with other organisms, the susceptibility of genes to RNA-mediated suppression may be gene specific and that design of antisense and ribozyme genes will be an empirical process.

Adenine↗
PubMed1995

The expression of antisense and ribozyme genes targeting citrus exocortis viroid in transgenic plants.

Four ribozyme and antisense genes targeting citrus exocortis viroid (CEVd) positive- and negative-strand RNA molecules were constructed and used to transform the tomato Lycopersicon lycopersicum cv. UC82B. The tomato is a readily transformable plant and will support replication of CEVd following mechanical inoculation. The ribozyme genes contained three hammerhead catalytic motifs with long hybridizing arms and synthetic RNA transcripts were shown to cleave the target CEVd RNA molecule in vitro. Homozygous transgenic plants were produced from independent transformants expressing either ribozymes or antisense constructs. Inoculation of transgenic seedlings expressing antisense constructs targeting the negative-strand CEVd RNA molecule with CEVd resulted in a moderate reduction in the accumulation of CEVd RNA. In contrast, similarly inoculated transgenic plants expressing constructs targeting the positive-strand CEVd RNA molecule resulted in an increase in the rate of CEVd RNA accumulation. Addition of the ribozyme motifs to the antisense genes did not enhance their efficiency in the suppression of viroid replication and a moderation or elimination of the observed antisense effects was seen in plants expressing the corresponding catalytic RNA-encoding genes.

Citrus↗
PubMed1994

Overproduction and purification of Mycobacterium tuberculosis chaperonin 10.

The overexpression of the Mycobacterium tuberculosis chaperonin 10 (Cpn10)-encoding gene was accomplished using baculovirus expression vectors. The product was immunoreactive with a Cpn10 monoclonal antibody (mAb) and had an electrophoretic mobility identical to authentic Cpn10. The baculovirus system was most successful in terms of reaching nearly the full expression potential of the system. Recombinant Cpn10 was purified from recombinant baculovirus-infected Spodoptera frugiperda cells by isoelectrofocussing and size-exclusion chromatography. The baculovirus vector and purification methodology described represent a very powerful system for the large-scale production of the M. tuberculosis Cpn10 which may allow us to undertake structure-function analysis.

Animals↗
PubMed1994

The risk of myocardial infarction associated with the combined use of estrogens and progestins in postmenopausal women.

BACKGROUND: While observational studies have suggested that unopposed estrogens reduce the incidence of coronary disease in postmenopausal women, there are few data on the effect of combined therapy with estrogens and progestins--a regimen adopted in recent years to minimize the risk of endometrial hyperplasia and cancer. In clinical trials, the addition of progestins has an adverse effect on serum lipid levels, and these lipid effects have raised the question of whether combined estrogen-progestin therapy increases the risk of coronary disease compared with the use of estrogen alone. METHODS: We conducted a population-based, case-control study among enrollees of Group Health Cooperative of Puget Sound. Cases were postmenopausal women who sustained an incident fatal or nonfatal myocardial infarction in 1986 through 1990. Controls were a stratified random sample of female Group Health Cooperative enrollees frequency matched to the cases by age and calendar year. We reviewed the medical records of the 502 cases and 1193 controls and conducted brief telephone interviews with consenting survivors. The health maintenance organization's computerized pharmacy database was used to ascertain the use of postmenopausal hormones. For the primary analysis of current use, we classified women into one of three groups: (1) nonusers of hormones; (2) users of estrogens alone; or (3) users of combined therapy including both estrogens and progestins. Each group of hormone users was compared with nonusers. RESULTS: After adjustment for potential confounding factors, the risk ratio of myocardial infarction associated with current use of estrogens alone was 0.69 (95% confidence interval, 0.47 to 1.02); and the risk ratio of myocardial infarction associated with current use of combined therapy was 0.68 (95% confidence interval, 0.38 to 1.22). Duration of combined-therapy use was relatively short, averaging less than 2 years in cases and controls. CONCLUSIONS: In this case-control study, the reduced risk of myocardial infarction associated with the use of estrogens alone was consistent with previous observational studies. Although the 95% confidence interval only excluded a risk above 1.22, the current use of combined therapy was not associated with an adverse effect on the incidence of myocardial infarction in postmenopausal women.

Aged↗
PubMed1994

Artificial ribozyme and antisense gene expression in Saccharomyces cerevisiae.

A sensitive, quantitative reporter gene-based experimental system for the in vivo analysis of hammerhead ribozyme and antisense gene function in Saccharomyces cerevisiae is described. The system was constructed to test the activity of ribozyme and antisense genes targeting the chloramphenicol acetyltransferase gene (CAT) in both a cis and trans configuration relative to the target. When both target and ribozyme or antisense genes were transcribed in the same mRNA from an expression vector, CAT expression was reduced by up to 90%. Although the cis-positioned ribozyme molecule cleaved the target RNA in vitro, the steady state RNA levels of these chimeric transcripts were increased several fold relative to control mRNAs. This observation indicates a mechanism of suppression of CAT gene expression other than duplex-dependent degradation of mRNA. When the ribozyme or antisense genes were transcribed in trans from a plasmid-based expression vector, expression of a CAT gene integrated into a chromosome was unaffected. The effect of the cis-located RNA molecules may be dependent on an interaction requiring co-localization of ribozyme or antisense and target mRNAs during or immediately after target gene transcription. The failure of such a co-localization of these RNAs when synthesized in trans may contribute to the lack of efficacy seen in the trans-acting ribozymes or antisense RNAs. These observations are consistent with other studies reporting inefficient trans-acting ribozyme and antisense activity in S. cerevisiae.

Chloramphenicol O-Acetyltransferase↗
PubMed1994

Antisense gene expression in yeast.

The use of antisense and ribozyme RNA to modulate gene expression is emerging as an effective genetic technique. A compilation of successful antisense gene suppression experiments reveals the absence of reports on the use of the yeast Saccharomyces cerevisiae as a host. We examine the field of antisense and ribozyme use in S. cerevisiae and discuss that this result is not due to any lack of attempts and may reflect unique features of S. cerevisiae biology. In an attempt to learn from cellular RNA physiology we review evidence for naturally occurring antisense RNA regulation. Although there are many examples of well characterised overlapping RNA transcripts there is, as yet, no clear evidence suggesting complementary RNA-dependent gene regulation in S. cerevisiae. The application of artificial antisense and ribozyme genes is then discussed with an emphasis on the role of yeast as a model system for the systematic and genetic analysis of antisense and ribozyme RNA function. In addition, potential reasons for the lack of attempts to use antisense or ribozyme genes to create pseudogenetic mutants are considered. We conclude that the application of successful antisense and ribozyme strategies in yeast may have to address features of S. cerevisiae RNA biology and offer experimental approaches that may identify some of these features.

Cell Cycle↗
PubMed1994

The Internet: will this highway serve the digital library?

The future of the biomedical enterprise and the biomedical libraries that serve it is tied closely to digital information. The changing nature of this type of information will create new pressures on libraries, particularly in health care organizations. Libraries must learn to deal with these pressures. Currently, libraries depend on the Internet primarily for connections to resources and other libraries; thus enhancements to the Internet will impact the libraries of the present and future significantly. This paper provides an overview of the technical capabilities that will be available in the near to midterm, what libraries will be able to do with those capabilities, and how libraries can position themselves to take advantage of the impending changes.

Computer Communication Networks↗