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Biomedical subjects

C Shaffer

Publications and source records attributed to C Shaffer.

18 recordsLinked to original sources
PubMed1999

Reliability and base rates of interpersonal themes in narratives from psychotherapy sessions.

We present an analysis of the reliability and base rates of the interpersonal contents of narratives told by patients in psychotherapy. Trained judges rated two samples, including 60 opiate-dependent patients in cognitive or psychodynamic therapy and 72 depressed patients in cognitive or interpersonal therapy. Using a comprehensive system based upon a circumplex model and involving 104 separate categories, we found that most categories of interpersonal behavior could be rated reliably. Potential problem categories were identified and strategies for increasing reliability are discussed. In particular, categories related to the concept of the introject (what the self does to the self) had low reliability. An analysis of the base rates of interpersonal themes revealed that issues related to autonomy/ assertion were most prevalent, although some differences between the two samples were evident. The implications of the results for research on narratives and models of psychotherapy are discussed.

Adult↗
PubMed1999

Aerosolization of P2Y(2)-receptor agonists enhances mucociliary clearance in sheep.

The purpose of this study was to determine whether aerosolized INS316 (UTP) stimulates lung mucociliary clearance (MCC) in sheep and, if so, to compare its effects with INS365, a novel P2Y(2)-receptor agonist. In the first series of studies, we used a previously described roentgenographic technique to measure tracheal mucus velocity (TMV), an index of MCC, before and for 4 h after aerosolization of INS316 (10(-1) M and 10(-2) M) and INS365 (10(-1) M and 10(-2) M), or normal saline in a randomized crossover fashion (n = 6). In a second series of studies, we compared the ability of these agents to enhance total lung clearance. For these tests, the clearance of inhaled technetium-labeled human serum albumin was measured serially over a 2-h period after aerosolization of 10(-1) M concentration of each agent (n = 7). Aerosolization of both P2Y(2)-receptor agonists induced significant dose-related increases in TMV (P < 0.05) compared with saline. The greatest increase in TMV was observed between 15 and 30 min after drug treatment. The highest dose (10(-1) M) of INS316 produced a greater overall stimulation of TMV than did INS365 (10(-1) M). Both compounds, compared with saline, induced a significant increase in MCC (P < 0.05) within 20 min of treatment. This enhancement in MCC began to plateau at 60 min. Although the response to INS316 started earlier, there was no significant difference between the clearance curves for the two compounds. We conclude that inhaled P2Y(2)-receptor agonists can increase lung MCC in sheep and that for P2Y(2)-receptor stimulation TMV accurately reflects changes in whole lung MCC.

Aerosols↗
PubMed1996

Equilibrium and transient state spectrophotometric studies of the mechanism of reduction of the flavoprotein domain of P450BM-3.

The flavoprotein domain of P450BM-3 (BMR), which is functionally analogous to eukaryotic NADPH-P450 oxidoreductases, contains both FAD and FMN. When BMR is titrated with NADPH or sodium dithionite under anaerobic conditions, addition of 2 electron equivalents per mole of BMR results in the reduction of the high potential flavin (FMN) without the accumulation of semiquinone intermediates. Additional sodium dithionite first produces some neutral, blue flavin semiquinone radical and, finally, fully reduced FADH2. During reduction with NADPH, an absorbance increase characteristic of the formation of a flavin-pyridine nucleotide charge-transfer complex was observed only during the addition of the second mole of NADPH per mole of BMR. On the basis of these results, we conclude that the midpoint reduction potential for the FMN semiquinone/FMNH2 couple is more positive than that for FMN/FMN semiquinone. The kinetics of reduction of BMR with NADPH were studied by stopped-flow spectrophotometry. With a 1:1 ratio of NADPH to BMR, the absorbance changes can be fit to five consecutive first order reactions with rate constants of 350 s-1, 130 s-1, 27 s-1, 2.3 s-1, and 0.05 s-1. These reactions are most probably the following: (a) complex formation between BMR and NADPH; (b) reduction of FAD with formation of the NADP(+)-FADH- charge-transfer complex; (c) transfer of the first electron from FADH- to FMN to form an anionic, red FMN semiquinone leaving the FAD as the neutral, blue semiquinone. Precise identification of intermediates beyond this point is difficult. In the presence of a 10-fold molar excess of NADPH, the absorbance changes and rate constants are somewhat different due to the formation of several additional reduced species of BMR. The rate of the first step increases, confirming that this is the formation of the NADPH-BMR complex. Our results indicate that the kinetic and thermodynamic control of the flavins in BMR is significantly different from that in microsomal P450 reductase. The low potential of the anionic FMN semiquinone can be utilized to reduce the P450 heme. When the anionic semiquinone becomes protonated, its potential becomes more positive and it is readily reduced to FMNH2, which is not capable of reducing P450.

Anaerobiosis↗
PubMed1996

Molecular characterization of the lysosomal acid phosphatase from Drosophila melanogaster.

In Drosophila, unlike humans, the lysosomal acid phosphatase (Acph-1) is a non-essential enzyme. It is also one of the most rapidly evolving gene-enzyme systems in the genus. In order to determine which parts of the enzyme are conserved and which parts are apparently under little functional constraint, we cloned the gene from Drosophila melanogaster via a chromosomal walk. Fragments from the gene were used to recover an apparently full-length cDNA. The cDNA was sub-cloned into a Drosophila transformation vector where it was under the control of the 5' promoter sequence of the hsp-70 gene. Three independent transformants were obtained; in each, Acph-1 expression from the cDNA was constitutive and not dependent on heat shock, as determined by densitometric analyses of the allozymic forms of the enzyme. The pattern of expression indicates the hsp-70 and endogenous Acph-1 promoters act together in some, but not all, tissues. The sequence of the cDNA was determined using deletions made with exonuclease III, and primers deduced from the cDNA sequence were used to sequence the genomic clone. Five introns were found, and putative 5' upstream regulatory sequences were identified. Amino acid sequence comparisons have revealed several highly conserved motifs between Drosophila Acph-1 and vertebrate lysosomal and prostatic acid phosphatases.

Acid Phosphatase↗
PubMed1995

Synthesis, deprotection, analysis and purification of RNA and ribozymes.

Improvements in the synthesis, deprotection and purification of oligoribonucleotides are described. These advances allow for reduced synthesis and deprotection times, while improving product yield. Coupling times are reduced by half using 5-ethylthio-1H-tetrazole (S-ethyltetrazole) as the activator. Base and 2'-O-t-butyldimethylsilyl deprotection with methylamine (MA) and anhydrous triethylamine/hydrogen fluoride in N-methylpyrrolidinone (TEA.HF/NMP), respectively, requires a fraction of the time necessitated by current standard methods. In addition, the ease of oligoribonucleotide purification and analysis have been significantly enhanced using anion exchange chromatography. These new methods improve the yield and quality of the oligoribonucleotides synthesized. Hammerhead ribozymes synthesized utilizing the described methods exhibited no diminution in catalytic activity.

Base Sequence↗
PubMed1993

Nurse manager characteristics and skills: curriculum implications.

If one accepts the premise that all nurses need knowledge of management and leadership, then schools of nursing need to design their curriculum to provide administrative content and learning experiences to adequately prepare nurses for leadership positions. This study assays the opinions of nurse unit managers about the relative importance of different characteristics and skills in effective job performance. A sample of 73 unit managers from six hospitals and two community health agencies ranked human relations and communication skills as most important. Nursing knowledge and clinical skills were ranked second. Experienced managers thought political savvy and business or management skills were more important than did novice managers. The results of this study are discussed in relation to curriculum issues in nursing management at both the baccalaureate and the graduate level.

Attitude of Health Personnel↗
PubMed1992

Manager responsibilities in community agencies and hospitals.

Nurse executives facilitate the success of unit managers through job design, control of organizational environment, and the selection and development of managers. This article reports the results of a descriptive study that assesses the responsibilities and activities of nursing unit managers in hospital and community health settings. This information may be used by nursing administrators when refining nursing unit manager roles within their agencies.

Community Health Centers↗
PubMed1991

Merging expertise and resources for research.

Nurse educators and nurse administrators share an interest in research. When a group of nursing administrators identified a need for research in their community hospital, a collaborative effort was initiated with a nurse educator from a nearby school of nursing. The successful collaborative effort proceeded through the four stages as identified by Keefe, Pepper, and Stoner (1988): Initiation, generation, incorporation, and validation. The activities and outcomes of each stage are described. The results of the collaborative effort were positive, creating advantages for all involved.

Diffusion of Innovation↗
PubMed1987

Inhibition by amiloride analogues of Na+-dependent hexose uptake in LLC-PK1/Cl4 cells.

Amiloride and four analogues of amiloride were shown to inhibit Na+-dependent, phlorizin-sensitive hexose uptake by a clone of pig kidney cells, LLC-PK1/Cl4. The analogues tested were: 5-(N-ethyl-N-isopropyl)amiloride (EIPA), 5-(N-methyl-N-isobutyl)amiloride (MIBA), 3',4'-dichlorobenzamil, and phenamil. The transport substrate was the nonmetabolizable glucose analogue alpha-methyl-D-glucoside. Blockade of Na+-K+ transport at the basolateral membranes or removal of divalent cations from the assay medium had little effect on the initial rate of hexose uptake, whereas MIBA remained an effective inhibitor under both conditions. The inhibitions by EIPA of Na+-H+ exchange and hexose-dependent Na+ uptake could be distinguished by appropriate choice of concentrations of the inhibitor. Hexose transport inhibition does not appear to be secondary to other known effects of the amilorides. Inhibition by all analogues is enhanced when they are tested in low (2 mM) Na+ medium, where they show half-maximal inhibition in the range of 100-300 microM. More detailed kinetic analysis of inhibition by EIPA shows it to be competitive with Na+ with a Ki of 73-107 microM. It is concluded that the amilorides are acting directly on the hexose transporter.

Amiloride↗
PubMed1983

Growth-dependent AIB and meAIB uptake in LLC-PK1 cells: effects of differentiation inducers and of TPA.

Cultured pig kidney cells designated LLC-PK1, previously shown to acquire Na+-dependent concentrative transport of hexoses as the cells become growth arrested, also show Na+-dependent concentrative uptake of the amino acid analogs alpha-aminoisobutyric acid (AIB) and (methyl) meAIB. This A system-like transport is most active in sparse, growing cultures and becomes stepped down at confluence. The cell/medium equilibrium distribution ratio of the lipophilic cation tetraphenylphosphonium ion (TPP+) decreases in parallel fashion, suggesting that a decrease in membrane potential may be a major factor in the stepdown. Differentiation inducers (hexamethylene bisacetamide) and phosphodiesterase inhibitors (theophylline, methylisobutyl xanthine) accelerate the stepdown, but even in the presence of these compounds addition of the tumor promoter 12-0-tetradecanoylphorbol-13-acetate (TPA) results in the maintenance of a high level of AIB and meAIB uptake. In all these respects the changes in A system-like amino acid transport are the reciprocal of those seen for concentrative hexose transport, although the driving force appears to be the same for both systems. The TPA analogs phorbol and 4-0-methyl TPA which are inactive in tumor promotion are inactive in this system as well. In confluent, already stepped-down cultures, addition of TPA leads to a rapid (2-6 hour) stimulation of AIB and meAIB uptake. The enhancement is sensitive to cycloheximide and actinomycin D. The ouabain-sensitive fraction of meAIB uptake is not markedly changed in the TPA-enhanced uptake, nor is the TPP+ distribution ratio elevated in TPA-treated cells, making it unlikely that the TPA effect is through an alteration in the membrane potential.

1-Methyl-3-isobutylxanthine↗
PubMed1982

Uptake of [3H]ouabain from the cell surface into the lysosomal compartment of HeLa cells.

[3H]Ouabain specifically bound at sublethal concentrations to Na,K-ATPase on the surface of HeLa cells is taken up (internalized) by the cells at a rate of three membrane equivalents of labeled sites per generation. Immediately following a pulse label with the glycoside, codistribution of radioactivity with the surface marker 5'-nucleotidase is found in both conventional sucrose-gradient fractionation and in fractionation following a digitonin treatment. At appropriate concentrations digitonin increases the buoyant density of the HeLa surface membrane and solubilizes the lysosomal marker beta-hexosaminidase (Tulkens et al., 1974). After internalization, [3H]ouabain is also solubilized by digitonin. A shear analysis is described which shows internalized ouabain and beta-hexosaminidase to be codistributed in a particulate fraction that is homogeneous with respect to shear; extrapolation to zero-shear shows that little or none of either marker is found in the soluble fraction of the cytosol. Both markers are coreleased from the particulate fraction by osmotic shock. Although internalized ouabain is subsequently released from these cells with a half-time of about 70 hr, apparently by exocytosis, the shear sensitivity of the remaining cell-associated ouabain does not change for up to 72 hr. Thus ouabain (together with Na,K-ATPase?) appears to be taken up from the surface into a lysosomal compartment and, by at least one criterion, this compartment does not change its physical properties with time, i.e., does not "age."

Biological Transport↗
PubMedDate not supplied

Faculty performance appraisal systems: procedures and criteria.

This study investigated the consensus among schools of nursing in (1) using the eight elements of effective performance appraisal identified in the literature and (2) identification of domains, dimensions, and subdimensions of faculty performance. Content analysis was done of actual policies, procedures, and forms from 86 schools with graduate programs. Performance appraisal systems were found to be in an early stage of development. There was substantive agreement on teaching, service, and research as domains, with 25% or fewer schools also using faculty development, professional practice, and/or administration. There was less consensus as to the attributes of domains. Specific dimensions and their assignment to domains, as well as recommendations to guide future development, are discussed.

Education, Nursing, Graduate↗
PubMedDate not supplied

Characteristics, perceived stressors, and coping strategies of patients who experience neurally mediated syncope.

PURPOSE: The purpose of this study was to describe the characteristics, perceived stressors, and coping strategies of patients who experience neurally mediated syncope. METHODS: Qualitative and quantitative analyses of 65 medical records including both written records and videotaped interviews were performed. FINDINGS: The most frequently reported health problems were gastrointestinal disturbances (61.3%), mood disturbances (56.5%), headaches (53.2%), and chronic fatigue (47.4%). Risk for injury was high, with 54.1% of subjects indicating that they had an episode that resulted in a fall and 44.3% indicating that they had sustained an injury as a result of syncope. Distressing symptoms such as fatigue, dizziness, nausea, chest pain, headache, confusion, and dyspnea often persisted for hours or days after an episode of syncope. Coping strategies included limiting or changing activities and avoiding injury. CONCLUSIONS: Neurally mediated syncope is a disruptive, distressing disorder that is a source of significant disability. Comprehensive care should include a holistic assessment of the impact of the disorder and appropriate referrals or interventions for psychologic, social, and occupational issues.

Adaptation, Psychological↗