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D White

Publications and source records attributed to D White.

At least 217 records · Page 12Linked to original sources
PubMed1991

Continuing education--within the intensive care unit. An essential requirement for promoting expert practice and reducing perceived staff stress.

This paper describes research designed to explore the relationship between perceived staff stress and continuing education needs for varying categories of registered nurses. A self rating instrument was used, a pilot study conducted and then data collected from registered nurses (n = 49) working in a general ICU. The data was analysed and compared in relation to perceived practice level, critical care nursing qualifications and time worked in ICU. The results demonstrated differences between those staff with critical care certificates and those without in relation to contributing factors to unpleasant stress, focus of continuing education sessions and involvement in continuing education.

Education, Nursing, Continuing↗
PubMed1990

Presence of a new microtubule cold-stabilizing factor in bull sperm dynein preparations.

Brain tubulin polymerized with dynein isolated from bull spermatozoa forms cold-stable microtubules, in contrast with microtubules made of brain tubulin polymerized by brain microtubule-associated proteins (MAPs). The level of cold-stable microtubules depends on the concentration of dynein used. Addition of dynein to cold-unstable microtubules renders these microtubules stable to cold. Although ATP and a non-hydrolysable ATP analogue increase the formation of microtubules made of tubulin and dynein, these nucleotides have no effect on dynein cold-stabilizing properties. The data suggests that a new factor, not involving the dynein ATPase active site and present in bull sperm dynein preparations, confers cold-stability to microtubules.

Adenosine Triphosphate↗
PubMed1990

Marketers hone their skills to reach target markets.

New challenges lie ahead for health care marketers. Marketers must communicate with several important groups: their own administration, the general public, employers, hospital employees, and, of course, physicians. And as budgets tighten, the methods used to communicate must become more creative and more efficient.

Attitude of Health Personnel↗
PubMed1990

Cell cycle-dependent transcriptional and post-transcriptional regulation of chloroplast gene expression in Chlamydomonas reinhardtii.

The regulated expression of five chloroplast genes in Chlamydomonas reinhardtii during a 24 hour cell cycle (12 hours light, 12 hours dark) was analyzed. Transcription rates of the genes encoding the two reaction center proteins of Photosystem I (psaA, psaB), the subunits alpha and beta (atpA, atpB) of chloroplast ATP synthase and for chloroplast elongation factor tu (EF-tu) were measured during the cell cycle. All genes are maximally transcribed at the beginning of the light period. Transcription was induced before the onset of illumination by a light-independent mechanism. Transcript abundance of the same genes during the cell cycle was determined by quantification of Northern blots hybridized with gene-specific probes. The atpA, atpB and psaB mRNAs were most abundant in the first 6 hours of the light period and decreased to about 15% of maximum in the dark. The abundance of psaA mRNA showed less variation and was maximal around the middle of the cell cycle. The EF-tu mRNA showed a maximum early in the light period, but decreased to almost undetectable levels in the second half of the light period. Because of the similar transcriptional patterns observed, the differential steady state levels of these chloroplast transcripts appeared to be regulated at the post-transcriptional level.

Blotting, Northern↗
PubMed1990

Fatty acid and lipopolysaccharide analyses of three Heliobacterium spp.

The cellular fatty acids from Heliobacterium chlorum, Heliobacterium gestii, and Heliobacillus mobilis were analyzed. The fatty acid contents of the three organisms were essentially the same, consisting of large amounts of branched chain and some mono-unsaturated fatty acids. Neither a phenol-water nor a phenol-petroleum ether-chloroform extraction of whole cells yielded lipopolysaccharide.

Bacteria↗
PubMed1990

Chemical modification of spinach plastocyanin using 4-chloro-3,5-dinitrobenzoic acid: characterization of four singly-modified forms.

Chemical modification of plastocyanin was carried out using 4-chloro-3,5-dinitrobenzoic acid, which has the effect of replacing positive charges on amino groups with negatively charged carboxyl groups. Four singly-modified forms were obtained which were separated using anion exchange FPLC. The four forms were modified at the N-terminal valine and at lysines 54, 71 and 77. The rates of reaction with mammalian cytochrome c were increased for all four modified plastocyanins. In contrast, the rates of reaction with cytochrome f were inhibited for the forms modified at residues 1, 54 and 77, whereas no effect was observed for the form modified at residue 71. Modification had no effect on either the midpoint redox potential or the reaction with K3Fe(CN)6. These results are consistent with a model in which charged residues on plastocyanin located at or near the binding site for cytochrome f recognize the positively-charged binding site on cytochrome f. In contrast, charged residues located at points on plastocyanin distant from the cytochrome f binding site recognize the net negative charge on the cytochrome f molecule. Based on these considerations, Glu-68 may be within the interaction sphere of cytochrome f, suggesting that cytochrome f may donate electrons to plastocyanin at either Tyr-83 or His-87.

Amino Acid Sequence↗
PubMed1990

A chamberless field exposure system for determining the effects of gaseous air pollutants on crop growth and yield.

A modification of the chamberless Zonal Air Pollution System (ZAPS) has been developed to permit the exposure of crops to various regimes of exposure to gaseous air pollutants under true field conditions. It provides 12 different levels and patterns of pollutant exposure, simulating a wide range of ambient conditions. The different levels and patterns of exposure are achieved through different rates of discharge of pollutant-enriched gas through manifolds suspended above individual plots. A feature of the layout is that, since the plots are grouped together in blocks of four, wind speed and direction dictate the actual exposure patterns received in any plot. For studies with ozone, O(3), enrichment of the ambient air occurs daily between 0700 and 2059 h (PDT). The overall O(3) concentration supplied to the manifolds is maintained proportional to that in the ambient air, except during the first 3 and the last 3 h of each enrichment period when enrichment is slowly increased and decreased, respectively, to provide smooth transitions from and to the ambient level. Additional control progressively reduces enrichment at low wind speeds. Over a season, the ZAPS results in typical unimodal distributions of concentrations on each plot, with good vertical mixing and reasonable horizontal distributions achieved by the large numbers of discharge orifices in the manifolds. Summary results from two seasons' experiments with processing peas are presented to provide examples of the use of the ZAPS to determine crop yield responses to ozone, based on simple linear regressions of yield against two different exposure indices.

Journal Article↗
PubMed1990

Delayed anterior decompression in patients with spinal cord and cauda equina injuries of the thoracolumbar spine.

Forty-nine patients with complete and incomplete injuries of the spinal cord or cauda equina who had undergone anterior decompression at a minimum of 3 months after injury were examined. Follow-up was from 12 months to 19 years. Postoperative neurologic improvement occurred in 46.5% of patients with incomplete injuries. If the surgery was performed less than 2 years after injury, neurologic improvement occurred in 68% with an improvement in Frankel grade of 32%. Bladder function improved in 27% of patients and if operated on less than 2 years after injury improvement occurred in 43%. Conus medullaris decompression resulted in a 50% improvement. There was an 83% improvement in the pattern of pain after decompression. Of 23 patients with preoperative spasticity, 10 improved but 6 were worse after surgery.

Adult↗
PubMed1990

In vitro and in vivo effects of monoclonal antibodies against T cell subsets on allogeneic and xenogeneic responses in the rat.

The Syrian hamster-to-rat represents an example of a concordant species difference, and therefore organ transplants using the hamster as the donor and the rat as the recipient are not rejected hyperacutely, as in discordant species combinations. Cellular mechanisms of xenogeneic rejection of hamster hearts by rats were studied both in vitro and in vivo, using monoclonal antibodies to rat T cell antigens. The results of this study reveal that CD4-positive cells of rats proliferated in vitro to both allogeneic stimulators and xenogeneic stimulators from a concordant strain, but required accessory cells of the responder phenotype to proliferate to discordant human stimulators. Monoclonal antibody therapy was used to prevent graft rejection in allogeneic and xenogeneic species combinations, using the rat as the recipient. Treatment with anti-CD4 antibodies was effective in prolonging allograft survival across a full MHC mismatch. No rejection occurred during antibody therapy, and long-term graft survival was achieved in 1/3 of transplanted grafts. The same monoclonal antibody therapy led to increased survival of grafts from hamster donors, but all of these grafts were rejected during therapy, and no long-term graft survival was achieved. Anti-CD8 antibody therapy, combined with anti-CD4 did not improve survival of hamster hearts in rats. Addition of cyclosporine to the anti-CD4 regimen also did not improve graft survival. Injection of an anti-T cell receptor antibody was no better than the anti-CD4 antibody in prolonging the survival times of heart grafts from the concordant xenogeneic species. These data suggest that the rejection of concordant xenogeneic tissue is not wholly a T cell-dependent phenomenon.

Animals↗
PubMed1990

Oxidation of Lignin-Related Aromatic Alcohols by Cell Suspensions of Methylosinus trichosporium.

Cell suspensions of Methylosinus trichosporium oxidized the aromatic alcohols benzyl alcohol, vanillyl alcohol, and veratryl alcohol to the corresponding aldehydes, and with the exception of vanillyl alcohol, the aldehydes were further oxidized to the corresponding aromatic acids. No other transformation was observed, and the methoxyl moieties attached to the aromatic nucleus remained intact. More than 70% of the alcohol oxidized could be accounted for by aldehyde and/or acid. Investigation of the inhibitor kinetics of EDTA or p-nitrophenylhydrazine (specific for NAD-independent methanol dehydrogenase in methylotrophs) on aromatic alcohol oxidation revealed noncompetitive inhibition in which the V(max) was decreased but the K(m) remained unchanged. The pattern of inhibition of aromatic alcohol oxidation matched that of methanol oxidation, and the K(m) values for all of the substrates were similar (12 to 16 mM). The results indicate that the initial step in the oxidation of aromatic alcohols was similar to that for methanol, and because oxidation was incomplete (i.e., only the corresponding aldehyde or acid was produced), there may be some biotechnological advantages in using whole cells of methylotrophs to facilitate aromatic biotransformations.

Journal Article↗
PubMed1990

High- versus standard-dose megestrol acetate in women with advanced breast cancer: a phase III trial of the Piedmont Oncology Association.

One hundred seventy-two patients with advanced breast cancer were randomized to receive oral standard-dose megestrol acetate (MA), 160 mg/d or high-dose MA, 800 mg/d. All but two patients had one prior trial of tamoxifen therapy for either metastatic disease (74%) or as adjuvant treatment (26%). Pretreatment characteristics were similar for both arms. High-dose MA resulted in a superior complete plus partial response rate (27% v 10%, P = .005), time to treatment failure (median, 8.0 v 3.2 months, P = .019), and survival (median, 22.4 v 16.5 months, P = .04) when compared with standard-dose therapy. These differences remained significant after adjustment for other covariates. Thirty-four patients were given high-dose MA after failure of standard-dose MA treatment, and none responded. Weight gain was the most distressing side effect, with 13% of standard-dose and 43% of high-dose patients gaining more than 20 lbs. Four major cardiovascular events occurred in patients receiving high-dose treatment and one in patients given standard doses. Other toxicity was modest. High-dose MA may represent a significant improvement in secondary endocrine therapy for advanced breast cancer patients refractory to initial endocrine treatment, but its use on a regular basis should be reserved until these results are confirmed by other clinical trials.

Adult↗
PubMed1990

Pharmacokinetics and dosage regimens of anti-inflammatory drugs.

The term anti-inflammatory drug, in its broadest sense, encompasses a number of very diverse compounds, ranging from steroids to non-steroidal anti-inflammatory drugs (NSAIDs) and from disease modifying agents (used in the treatment of canine rheumatoid arthritis) to chondroprotective agents (used in the treatment of osteoarthrosis and traumatic arthritis in the horse). For many of these drugs (eg, chondroprotective and disease modifying agents) the mode of action is unknown and even with steroids and NSAIDs there is no universal agreement on mechanism of action. It is therefore in many cases impossible to link pharmacokinetic data to a drug's pharmacodynamics, for example to an effect on a specific biochemical marker. Some agents, including corticosteroids, may have indirect modes of action, so that the pharmacodynamic half-life can be much longer than (and not clearly related to) the pharmacokinetic half-life. In other cases, clinical benefits may only become apparent after several weeks or even months. It can therefore be difficult or impossible to use classical pharmacokinetic approaches to set dosing intervals and dose rates for clinical use. To some extent, the position is more straightforward with NSAIDs. However, even with these drugs simple approaches are not possible and this paper will review briefly some of the studies undertaken in our laboratory which have attempted to utilize NSAID kinetics to set dosage schedules for clinical use.

Animals↗