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Biomedical subjects

M J Clark

Publications and source records attributed to M J Clark.

At least 37 records · Page 2Linked to original sources
PubMed1999

The effects of an intervention campaign to enhance seat belt use on campus.

The national health objectives for the year 2000 called for an increase in the use of safety restraints to 85% of motor vehicle occupants. An assessment on one campus indicated that only 79% of those observed were wearing seat belts. Nursing faculty and students undertook a multimodal intervention campaign to increase seat belt use in the campus community. Observed use of seat belts increased to 81% after the week-long intervention consisting of reminder banners, media coverage, permanent reminder signs, roll-over demonstrations, a presentation on the need for seat belt use, and distribution of seat belt use pledge cards. Although the increase was small, it was statistically significant and could represent considerable savings in healthcare costs if even 2% of the population could be saved from serious injury by using seat belts. In addition, the change in seat belt use represented a decline of nearly 10% in the number of nonusers.

California↗
PubMed1999

Older people's use of ambulance services: a population based analysis.

OBJECTIVE: To investigate the use of emergency and non-urgent ambulance transport services by people aged 65 years and over. SETTING: The study was undertaken in Queensland where the Queensland Ambulance Services (QAS) is the sole provider of emergency pre-hospital and non-urgent ambulance services for the entire state. METHODS: The age and sex of 351,000 emergency and non-urgent cases treated and transported by the QAS from July 1995 to June 1996 were analysed. RESULTS: People aged 65 years and over who comprise 12% of the population utilise approximately one third of the emergency and two thirds of the non-urgent ambulance resources provided in Queensland. While the absolute number of occasions of service for females for emergency services is higher than for males, when the data are stratified for age and sex, males have higher rates of emergency ambulance service utilisation than females across every age group, and particularly in older age groups. Gender differences are also found for non-urgent ambulance usage. The absolute number of occasions of service for older females aged 65 and over using non-urgent ambulance transport is high, but utilisation patterns on stratified data reveal similar gender usage patterns across most age groupings, except at the older age groupings where male usage greatly exceeds female usage. CONCLUSIONS: As the aged are disproportionately high users of ambulance services, it will become increasingly important for ambulance services to plan for the projected increase in the aged population. Emergency pre-hospital care is one of the few health services along the continuum of care where male usage patterns are higher than those of females. More information needs to be obtained on the age and presenting characteristics of those people who are multiple users of the ambulance service. Such information will assist service planners.

Adolescent↗
PubMed1999

Opioid efficacy in a C6 glioma cell line stably expressing the human kappa opioid receptor.

A C6 glioma cell line stably transfected with the human kappa opioid receptor (kappaOR) was used to characterize receptor binding and G protein activation via the kappaOR by a comprehensive series of opioid ligands. The ligand-binding affinity for [3H]5alpha,7alpha, 8beta(-)-N-methyl-N-(7-Cl-pyrrolidinyl)-1-oxaspiro(4, 5)dec-8-yl)benzene acetamide (U69593) was similar to that observed in monkey brain membranes and was 10-fold lower in the presence of sodium and GDP. Both peptide and nonpeptide agonists maximally stimulated [35S]GTPgammaS binding. The stimulation of [35S]GTPgammaS binding was blocked by pretreatment of cells with pertussis toxin. Partial stimulation of [35S]GTPgammaS binding via the kappaOR was observed for several ligands that are antagonists at the mu opioid receptor, suggesting an additional mechanism of drug action. The ability of isomers of tifluadom and levallorphan to stimulate [35S]GTPgammaS binding indicates that the chiral carbon of levallorphan, a benzomorphan derivative, imparts a greater degree of stereoselectivity than does the chiral carbon in the benzodiazepine derivative tifluadom. In addition, (-)tifluadom, the less potent isomer of tifluadom, which is also a gamma-aminobutyric acidA receptor agonist, stimulated [35S]GTPgammaS binding. In contrast, d-pentazocine, (+)SKF10047, (+)cyclazocine, and d-ethylketocyclazocine displayed no agonist activity. kappaOR-selective antagonist norbinaltorphimine competitively inhibited the stimulation of [35S]GTPgammaS binding by the active isomers of ethylketocyclazocine, cyclazocine, and nalorphine to the same degree, indicating that all three ligands are eliciting an effect via the kappaOR. The results suggest that these cells express a homogeneous population of kappaOR, and that their [35S]GTPgammaS-binding properties make them an excellent means to assess kappaOR efficacy.

Analgesics, Opioid↗
PubMed1998

Delta opioid receptor down-regulation is independent of functional G protein yet is dependent on agonist efficacy.

Chronic treatment of C6 glioma cells stably expressing the rat delta opioid receptor (C6delta) with full agonists resulted in receptor down-regulation. Chronic [D-Ser2,L-Leu5]enkephalyl-Thr treatment caused a decrease in cell surface as well as a decrease in agonist-stimulated [35S]guanosine-5'-O-(3-thio)triphosphate binding. Treatment with full agonists for 12 hr resulted in a 90% decrease in receptor number that was paralleled by a decrease in the ability of agonist to stimulate [35S]guanosine-5'-O-(3-thio)triphosphate binding and inhibit forskolin-stimulated adenylyl cyclase. Of the remaining receptors, a smaller fraction of receptors (41 +/- 4 vs. 56 +/- 4% in control) exhibited high affinity for agonist as compared to receptors in control membranes. Elimination of functional guanosine triphosphate binding protein (G protein) by Pertussis toxin pretreatment did not alter the ability of agonist to down regulate receptor. We hypothesized that agonist affinity (not efficacy) would be a predictor of an agonist's ability to down-regulate receptor. However, we found that only full agonists were able to down-regulate receptor number, G protein activation and adenylyl cyclase inhibition. Chronic exposure to partial agonist 7-spiroindinooxymorphone, which has a very high affinity for the receptor, as well as morphine, did not cause receptor down-regulation. Taken together, these results suggest that full agonists alter receptor conformation such that the altered conformation is recognized by G protein as well as proteins involved in receptor down-regulation. In addition, down-regulation is independent of agonist-mediated G protein activation and subsequent down-stream signaling.

Adenylyl Cyclase Inhibitors↗
PubMed1997

Life in the fast lane. An evaluation of an accelerated RN-MSN program.

The Pew Health Commission on professional education has recommended innovative educational programs to promote career mobility among nurses. To assure continued quality of nursing education in the face of innovation, the Philip Y. Hahn School of Nursing conducted a comprehensive evaluation of its accelerated RN-MSN program. Designed to enhance career advancement in the profession, the program was evaluated after its fourth year of operation using the Discrepancy Evaluation Model (DEM). Based on comparison with both relative and absolute standards, the program shortened the time required to obtain BSN and MSN degrees and appeared to reverse declining enrollments in the baccalaureate nursing program. Accelerated students were as successful as other masters nursing students in specific courses and in the program in general. Adverse program effects included declining enrollments in some under-graduate courses and the increased complexity of advising.

Career Mobility↗
PubMed1997

Nursing education: focus on flexibility.

Curricular change requires input from both service and education. However, it is sometimes difficult to obtain a complete picture of nursing practice from the clinical arena. The curriculum committee of the University of San Diego Philip Y. Hahn School of Nursing conducted a study with focus groups comprised of nurses from several different areas of practice to obtain information for curriculum changes. Both the focus group process and its outcomes are reported here. Flexibility was the key theme that emerged from all of the focus group sessions. Other themes were categorized in terms of issues addressed and included professional issues, healthcare systems issues, nursing education issues, and advanced practice issues. The focus group strategy proved to be an effective means of gaining the broad spectrum of insights needed for curriculum revision.

California↗
PubMed1997

Opioid efficacy in a C6 glioma cell line stably expressing the delta opioid receptor.

A C6 glioma cell line stably transfected with the rat delta opioid receptor (C6delta) was used to characterize receptor binding and G protein activation by both peptide and nonpeptide delta opioid ligands. The ligand binding affinities for [3H]naltrindole and [3H]pCl-[D-Pen2,D-Pen5]enkephalin (DPDPE) were similar to those observed in monkey brain membranes. The nonpeptide agonists, BW373U86 and SNC80, as well as peptide agonist [D-Ser2, L-Leu5]enkephalyl-Thr maximally stimulated [35S]GTPgammaS binding by 640, 654 and 576%, respectively, over basal. The peptide agonists, DPDPE and deltorphin II, both stimulated [35S]GTPgammaS binding by 375%. Etorphine, diprenorphine, oxymorphindole and 7-spiroindanyloxymorphone were also partial agonists in this assay, although they were less efficacious than deltorphin II. Stimulation of [35S]GTPgammaS binding by agonists was blocked completely by pertussis toxin pretreatment. Both delta-1 and delta-2 selective antagonists 7-benzylidenenaltrexone and a benzofuran analog of naltrindole displayed high affinity for the cloned receptor (0.04 and 0.08 nM) and antagonized the stimulation of [35S]GTPgammaS binding by BW373U86 and DPDPE with similar potencies. Other evidence suggesting the lack of receptor subtypes includes the finding that stimulation of [35S]GTPgammaS binding by receptor subtype selective ligands DPDPE and deltorphin II was not additive. BW373U86, SNC80 and DPDPE maximally inhibited forskolin-stimulated adenylyl cyclase. These cells highly express a homogeneous population of delta opioid receptor that couple to inhibitory Go/Gi proteins. Ligand affinity for the delta opioid receptor correlates with ligand EC50 values for stimulation of [35S]GTPgammaS binding.

Adenylate Cyclase Toxin↗
PubMed1996

Characterization of opioid agonist efficacy in a C6 glioma cell line expressing the mu opioid receptor.

In C6 glioma cells stably expressing a homogeneous population of the cloned rat mu opioid receptor, the binding affinities of opioid agonists and subsequent activation of G protein were examined. Opioid receptor number in membranes of these cells was high (10-30 pmol/mg protein [3H]diprenorphine binding sites). Opioids were found to bind to the receptor with high affinity [Tyr-D-Ala-Gly-(Me)Phe-Gly-ol (DAMGO) 0.23 nM; sufentanil 0.034 nM; morphine 0.16 nM]. Activation of G protein by opioid agonists was examined by measuring the stimulation of guanosine-5'-O-(3-[35S]thio)triphosphate ([35S]GTP gamma S) binding. Sufentanil increased [35S]GTP gamma S binding by 326% with an EC50 value of 2.39 nM. Agonist stimulation of [35S]GTP gamma S binding was stereoselective, naltrexone-reversible, and pertussis toxin-sensitive. The "intrinsic activity" of opioids at the mu receptor was reflected by the magnitude of agonist-mediated activation of G protein. The rank order of the stimulation of [35S]GTP gamma S binding was etonitazene = sufentanil = DAMGO = PLO17 = fentanyl > morphine > profadol > meperidine > butorphanol = nalbuphine = pentazocine > cyclazocine = nalorphine > levallorphan > naltrexone. High affinity binding of ligands to the mu opioid receptor was reduced by the addition of sodium and guanosine diphosphate at concentrations used in the [35S]GTP gamma S binding assay. Ligand affinity was reduced in a manner correlating with "intrinsic activity". DAMGO, 1229-fold, nalbuphine 35-fold, naltrexone, 3-fold. The results presented show that the stable expression of the rat mu opioid receptor in C6 cells provides an effective tool to examine opioid receptor signal transduction mechanisms and evaluate the activity of novel opioids at the mu receptor.

Animals↗
PubMed1995

enabled, a dosage-sensitive suppressor of mutations in the Drosophila Abl tyrosine kinase, encodes an Abl substrate with SH3 domain-binding properties.

Genetic screens for dominant second-site mutations that suppress the lethality of Abl mutations in Drosophila identified alleles of only one gene, enabled (ena). We report that the ena protein contains proline-rich motifs and binds to Abl and Src SH3 domains, ena is also a substrate for the Abl kinase; tyrosine phosphorylation of ena is increased when it is coexpressed in cells with human or Drosophila Abl and endogenous ena tyrosine phosphorylation is reduced in Abl mutant animals. Like Abl, ena is expressed at highest levels in the axons of the embryonic nervous system and ena mutant embryos have defects in axonal architecture. We conclude that a critical function of Drosophila Abl is to phosphorylate and negatively regulate ena protein during neural development.

Amino Acid Sequence↗
PubMed1995

Acuity classification in the urgent care setting.

Efforts to control costs but provide accessible services have led to the development of urgent care centers. Viable urgent care centers must provide cost-effective care while maintaining quality. This requires staff allocation appropriate to patient needs as well as volume. Few articles have been written on patient acuity systems that permit optimal urgent care center staffing. Sharp Rees-Stealy Medical Centers have developed an acuity system for use in the urgent care center.

Acute Disease↗
PubMed1995

Acoustic characteristics of American English vowels.

The purpose of this study was to replicate and extend the classic study of vowel acoustics by Peterson and Barney (PB) [J. Acoust. Soc. Am. 24, 175-184 (1952)]. Recordings were made of 45 men, 48 women, and 46 children producing the vowels /i,I,e, epsilon,ae,a, [symbol: see text],O,U,u, lambda,3 iota/ in h-V-d syllables. Formant contours for F1-F4 were measured from LPC spectra using a custom interactive editing tool. For comparison with the PB data, formant patterns were sampled at a time that was judged by visual inspection to be maximally steady. Analysis of the formant data shows numerous differences between the present data and those of PB, both in terms of average frequencies of F1 and F2, and the degree of overlap among adjacent vowels. As with the original study, listening tests showed that the signals were nearly always identified as the vowel intended by the talker. Discriminant analysis showed that the vowels were more poorly separated than the PB data based on a static sample of the formant pattern. However, the vowels can be separated with a high degree of accuracy if duration and spectral change information is included.

Adult↗
PubMed1995

Using a public health nursing model to assess and plan for health needs at a summer day camp.

The epidemiologic prevention process model (EPPM; Clark, 1992) was designed to guide community health nursing practice and research. The model incorporates epidemiologic, nursing, and public health perspectives and directs assessment of health needs and the planning, implementation, and evaluation of health care services at primary, secondary, and tertiary levels of prevention. The EPPM was used to assess needs for nursing services at a summer day camp and to plan to meet those needs. Assessment indicated that underlying factors in each of four components of the model (human biology, environment, lifestyle, and the health system) contributed to needs for nursing services. Assessment data were used to derive community nursing diagnoses and to plan interventions to meet identified health care needs. In this application, the EPPM was found to be an effective way of organizing and interpreting findings and of translating those findings into improved health care services in a camp setting.

Adolescent↗
PubMed1994

Specificity of bone morphogenetic protein-related factors: cell fate and gene expression changes in Drosophila embryos induced by decapentaplegic but not 60A.

Reported assays of the bone morphogenetic proteins (BMPs) have not in general revealed specific functions for the different proteins, belying the specificity implied by the evolutionary conservation and distinct expression patterns of the genes encoding BMPs. We have used assays of developmental function to show that the two Drosophila homologues of the BMPs, decapentaplegic (dpp) and 60A, that both induce ectopic bone formation in mammalian assay systems, have distinct effects in Drosophila development. A binary expression system using the yeast transcriptional activator GAL4 directed identical patterns of tissue and temporally specific dpp and 60A expression. When dpp enhancer elements drove GAL4 expression, GAL4-responsive dpp transgenes rescued dpp mutant phenotypes, but GAL4-responsive 60A transgenes did not. Ectopic ectodermal expression of dpp during gastrulation respecified the dorsal/ventral pattern of the embryo. In contrast, ectopic 60A expression had no detectable effects on embryonic development but led to defects in adult structures or lethality during metamorphosis. Expression of 60A in cells expressing dpp did not interfere with dpp functions, indicating that dysfunctional heterodimers did not form at sufficient levels to inhibit dpp. These specific developmental responses in Drosophila indicate that in vivo functions of BMP-like factors can be more specific than indicated by the ectopic bone formation assays and that the Drosophila embryo provides an assay system sensitive to the structural differences that contribute to BMP specificity in vivo.

Amino Acid Sequence↗
PubMed1993

Seat belt use on a university campus.

Observed seat belt use on a private university campus was compared with use by the general population of the state in which the university is located. It was expected, given the higher educational level and socioeconomic status of the university population, that seat belt use would be higher than it is for the general population. The results of the study indicated that seat belt use by members of the university community was actually significantly lower than that reported statewide. The statistically significant difference was even greater for front-seat passengers than for drivers on campus.

Data Collection↗
PubMed1993

Dose quantities and instrumentation for measuring environmental gamma radiation during emergencies.

The dosimetry for exposure to gamma radiation in the environment is reviewed, including the factors used to convert measurements of traceable quantities to effective dose equivalent. A value of 0.70 Sv Gy-1 is widely used to convert air kerma or absorbed dose-to-air to effective dose equivalent, but recent work shows that a value of 0.86 Sv Gy-1 is more appropriate for deposited radionuclides. The arguments are reviewed and the implications of using operational dose equivalent quantities defined by the International Commission on Radiation Units and Measurements are considered. For planar deposited sources in the environment, it is shown that the use of ambient dose equivalent quantities without applying conversion factors, could significantly overestimate effective dose equivalent. In contrast, the adoption of the new effective dose quantity defined by the International Commission on Radiological Protection in Publication 60 will have a small impact on conversion factors for gamma radiation in the environment. Practical aspects of measurement are also considered, and five instruments suitable for measuring environmental gamma radiation have been evaluated in the laboratory and in field tests. The instruments include models with scintillation detectors, a Geiger-Müller detector, and a high-pressure ionization chamber, the choice being influenced by those commonly used in European Community countries for routine and emergency monitoring. The main disadvantage of all the instruments is the lack of spectral information, so a straightforward emergency instrument capable of discriminating between natural and artificial radionuclides has also been evaluated.

Accidents↗
PubMed1993

Dosage-sensitive modifiers of Drosophila abl tyrosine kinase function: prospero, a regulator of axonal outgrowth, and disabled, a novel tyrosine kinase substrate.

In the absence of the Drosophila abl protein-tyrosine kinase (PTK), loss-of-function mutations in either disabled or prospero have dominant phenotypic effects on embryonic development. Molecular and genetic characterizations indicate that the products of these genes interact with the abl PTK by different mechanisms. The interaction between abl and prospero, which encodes a nuclear protein required for correct axonal outgrowth, is likely to be indirect. In contrast, the product of disabled may be a substrate for the abl PTK. The disabled protein is colocalized with abl in axons, its predicted amino acid sequence contains 10 motifs similar to the major autophosphorylation site of abl, and the protein is recognized by antibodies to phosphotyrosine.

Amino Acid Sequence↗