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D Nash

Publications and source records attributed to D Nash.

At least 55 records · Page 3Linked to original sources
PubMed1994

Expert systems. Assisting formulary decision making in the ambulatory setting.

In this article, the author reviews the application of a computer-assisted decision support system to their formulary decision-making process. Basic information is presented describing expert systems, which are a type of computer-assisted decision support system, and their advantages and disadvantages. A specific example of an expert system, 'RXPERT', is described. 'RXPERT' is a prototype expert system that models the decision-making process for an ambulatory (nonhospital) formulary. This formulary is the underpinning of the prescription drug benefit programme for the nearly 1 million residents of Saskatchewan, Canada. In the current formulary decision process, each drug product is evaluated by 2 separate committees, with the third and final decision resting with the Ministry of Health. The first committee, the Drug Quality Assessment Committee (DQAC), comprises members with expertise in medicine, pharmacology, clinical pharmacy, pharmaceutics, statistics, and regulatory processes. The DQAC evaluates information from the drug manufacturer and other independent sources, and makes an initial assessment with respect to clinical aspects of alternative therapies and generic interchangeability. The committee then makes its recommendation to the Saskatchewan Formulary Committee (SFC). The SFC reviews the recommendation of the DQAC and considers the administrative and economic implications of accepting the product for the patient, the programme, and healthcare professionals' practice. The SFC either reaffirms the recommendation of the DQAC or modifies it based on further review, and forwards its recommendation to the Ministry of Health. Finally, the Ministry of Health reviews the evaluation and determines the drug's formulary status.(ABSTRACT TRUNCATED AT 250 WORDS)

Decision Making, Computer-Assisted↗
PubMed1993

The adenosine2 gene of Drosophila melanogaster encodes a formylglycineamide ribotide amidotransferase.

Drosophila melanogaster genomic DNA spanning an adenosine2 gene rearrangement breakpoint (in cytological map region 26B1-2) was cloned and a composite ade2 base sequence was derived from this DNA and from a corresponding cDNA. Based on genetic evidence, the ade2 gene is thought to encode the purine biosynthetic enzyme formylglycineamide ribotide amidotransferase (FGARAT). The cDNA hybridizes to a 4.8-kb message that encodes a 1354 amino acid polypeptide with extensive similarity to Escherichia coli FGARAT. The D. melanogaster FGARAT amino acid sequence is considerably more like that of the E. coli enzyme than is the FGARAT of B. subtilis, which has two polypeptides with, collectively, 969 amino acids. It is suggested that the taxonomically anomalous similarity between the eukaryotic FGARAT and that from E. coli may indicate horizontal exchange of genetic material. On the basis of substantially greater conservation of sequences shared by all three species compared with those present only in E. coli and D. melanogaster, we suggest that no radical alteration of enzymatic function accompanied the transition between the single-gene and the two-gene state.

Amino Acid Sequence↗
PubMed1992

Gut associated lymphoid tissue in the cotton rat (Sigmodon hispidus) and its response to protein restriction.

We examined age and nutritional related changes in the distribution and size of gut associated lymphoid tissues in the intestinal tract of cotton rats (Sigmodon hispidus). Peyer's patches in the small intestine are prominent, ranging from four to 13, and increase in size (surface area) with age. The average Peyer's patch in the adult cotton rat measured 23.9 mm2. Lymphoid tissue in the cecum was primarily limited to a large aggregate located in the vermiform appendix, which increased in size with age. Age related changes in the number of visible lymphoid follicles in the large intestine were highly significant, increasing from 24.8 in juveniles to 45.1 in adults. Weights of dissectable Peyer's patch tissue in animals consuming a low protein diet were significantly lower in juveniles and greater in subadults compared to those on high protein diets. Relative weights of Peyer's patch tissue averaged 84 to 95% more in low protein-fed animals than in the group on the high quality protein diet. Our results suggest that peripheral lymphoid tissues in wild cotton rats are more resistant to protein deficiencies than other tissues in the body and could be a useful index for assessing nutritional status.

Aging↗
PubMed1992

P & T Committee response to evolving technologies: preparing for the launch of high-tech, high-cost products. Roundtable discussion.

P & T Committees are entering an exciting era in which the introduction of biotechnology-derived pharmaceuticals is providing life-saving opportunities for conditions for which there was little or no hope for a cure. The P & T Committee at Thomas Jefferson University Hospital has anticipated the challenge that these novel therapeutics present, and has already positioned itself for the pending approval of the first therapeutic human monoclonal antibody. Nebacumab (HA-1A, formerly known as Centoxin; by Centocor) will be used for the treatment of gram-negative sepsis. Although this antiendotoxin has a good side effect profile, its use also carries a high price tag. This will raise several difficult ethical issues once the product is introduced. In this exclusive Hospital Formulary roundtable, members of Thomas Jefferson's P & T Committee and Technology Assessment Subcommittee provide their insights for responsibly managing a high-tech, high-cost product such as nebacumab.

Antibodies, Monoclonal↗
PubMed1990

Genetic analysis of the adenosine3 (Gart) region of the second chromosome of Drosophila melanogaster.

The Gart gene of Drosophila melanogaster is known, from molecular biological evidence, to encode a polypeptide that serves three enzymatic functions in purine biosynthesis. It is located in polytene chromosome region 27D. One mutation in the gene (ade3(1)) has been described previously. We report here forty new ethyl methanesulfonate-induced mutations selected aga!nst a synthetic deficiency of the region from 27C2-9 to ++28B3-4. The mutations were characterized cytogenetically and by complementation analysis. The analysis apparently identifies 12 simple complementation groups. In addition, two segments of the chromosome exhibit complex complementation behavior. The first, the 28A region, gave three recessive lethals and also contains three known visible mutants, spade (spd), Sternopleural (Sp) and wingless (wg); a complex pattern of genetic interaction in the region incorporates both the new and the previously known mutants. The second region is at 27D, where seven extreme semilethal mutations give a complex complementation pattern that also incorporates ade3(1). Since ade3(1) is defective in one of the enzymatic functions encoded in the Gart gene, we assume the other seven also affect the gene. The complexity of the complementation pattern presumably reflects the functional complexity of the gene product. The phenotypic effects of the mutants at 27D are very similar to those described for ade2 mutations, which also interrupt purine biosynthesis.

Adenosine↗
PubMed1989

Drosophila purine auxotrophy: new alleles of adenosine 2 exhibiting a complex visible phenotype.

New mutant alleles of the adenosine2 locus (ade2; 2-17.7) have been isolated using the eye-color phenotype exhibited by the prototype auxotrophic allele ade2 as the screening criterion. The new mutants form a single complementation group, suggesting that they all exhibit purine auxotrophy and defective formylglycineamide ribotide amidotransferase enzyme, like ade2. Tests carried out on particular new alleles confirm these suggestions. The new mutants all exhibit more extreme physical defects than the prototype. They have wing abnormalities like mutants defective in pyrmidine biosynthesis and reduced bristles like those defective in protein synthesis; thus they exhibit the combined visible phenotype of rudimentary wings, rosy eyes, and bobbed bristles. Cytogenetic analysis places the locus in the interband proximal to 26B1-2.

Adenosine↗
PubMed1989

Inhibition of Crimean-Congo hemorrhagic fever viral infectivity yields in vitro by ribavirin.

Ribavirin was evaluated as a potential therapeutic for Crimean-Congo hemorrhagic fever (CCHF). Viral yields for strains of CCHF virus from Europe, Asia, and Africa in African green monkey kidney (Vero) cells were markedly reduced by this drug. Some CCHF viral strains appeared more sensitive than others, but in general, ribavirin doses as low as 5 micrograms/ml caused a transient reduction of viral yields. A further reduction in viral yields was induced by a dose of 25 micrograms/ml, and evidence of viral replication was not demonstrated in cells treated with 50 or 250 micrograms/ml. In contrast, a dose of ribavirin at least 9 times greater was required to induce a comparable inhibitory effect on the yields of Rift Valley fever virus, for which the drug has been shown to inhibit replication in monkeys and rodents.

Animals↗
PubMed1986

Two Drosophila melanogaster mutations block successive steps of de novo purine synthesis.

Drosophila melanogaster purine auxotrophs ade2(1) and ade3(1) have been characterized biochemically. The ade2(1) strain is deficient in the fourth step of the de novo purine synthetic pathway catalyzed by phosphoribosylglycinamidine synthase (phosphoribosylformylglycinamide amidotransferase). The ade3(1) strain is deficient in the previous step catalyzed by phosphoribosylglycinamide formyltransferase (GART). The mutation responsible for the slightly leaky ade3(1) phenotype was characterized further. First, the mutant GART polypeptide was found to be of normal size and present at normal levels. Second, the GART-encoding region of the mutant was cloned, inserted into a yeast-Escherichia coli shuttle vector, and used to transform mutant yeast. Transformants showed very slight in vivo activity when compared to wild type, verifying that the mutation is in the GART coding sequence. Lastly, the region of the gene encoding GART activity from mutant and inbred parental strain flies was completely sequenced. A single base transition was found, leading to the substitution of a serine for a highly conserved glycine. These two mutations provide examples of blocks in the de novo purine synthetic pathway in a whole animal.

Acyltransferases↗
PubMed1986

Heterogeneity of lethals in a "simple" lethal complementation group.

Of 24 ethyl methanesulphonate-induced, recessive-lethal mutations in the region 9E1-9F13 of the X chromosome of Drosophila melanogaster, eight fall into a typically homogeneous lethal complementation group associated with the raspberry (ras) locus. Mutations in this group have previously been shown to be pleiotropic, affecting not only ras but also two other genetic entities, gua 1 and pur 1, which yield auxotrophic mutations.--The eight new mutations have been characterized phenotypically in double heterozygotes with gua 1, pur 1 and ras mutations. Despite their homogeneity in lethal complementation tests, the mutations prove quite diverse. For example, two mutations have little or no effect on eye color in double heterozygotes with ras2. The differences between the lethals are allele-specific and cannot be explained as a trivial outcome of a hypomorphic series.--Taken alone, the lethal complementation studies mask the complexity of the locus and the diversity of its recessive lethal alleles. By extension, we argue that the general use of lethal saturation studies provides an unduly simplified image of genetic organization. We suggest that the reason why recessive lethal mutations rarely present complex complementation patterns is that complex loci tend to produce mutations that affect several subfunctions.

Animals↗
PubMed1986

Capital payment under PPS: can hospitals still bloom?

Capital costs are presently treated as pass-through payments under PPS. However, this situation is only temporary and by Oct. 1, 1986, HCFA must endorse a proposal to incorporate capital costs into the framework of PPS. Several methods have been suggested--a capital add-on approach, a modified pass-through approach, and variations of these two approaches. Looking at a case study hospital--a large urban teaching center--results show that the modified pass-through approach is the most advantageous, providing the largest cash flow.

Capital Expenditures↗