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Biomedical subjects

S Mackey

Publications and source records attributed to S Mackey.

At least 19 recordsLinked to original sources
PubMed2001

Psychiatric health service areas in the southeast.

Analysis of small areas in psychiatric health services research is sensitive to the choice of geographic units. To partially overcome the arbitrary aspects of political boundaries, service areas can be synthesized from empirical data on consumer migration patterns. Using patient flow data from 1991 Medicare discharges, we completed an agglomerative cluster analysis to generate psychiatric health service areas (PHSAs) and found that the optimal solution contained 75 PHSAs. Solutions greater than 75 clusters had high rates of area fragmentation and small single-county clusters. Psychiatric resource supply and health status indicators should be analyzed using expanded geographic units.

Catchment Area, Health↗
PubMed2000

Towards a definition of wellness.

The term 'wellness' is widely referred to in the nursing literature, yet its meaning remains elusive. Definitions vary widely, if they are provided. Lack of consensus regarding the definition of wellness contributes to fragmentation of access to research findings and limits understanding and action in wellness practice. This paper looks beyond individual definitions of the terms 'wellness' and 'health' to examine some conceptual similarities which may contribute to the debate.

Attitude to Health↗
PubMed1999

Therapeutic massage: an education program for rural and remote workers in the palliative care field.

This paper, drawing upon data from a Rural Health, Support, Education and Training (RHSET) funded project, focuses on the evaluation of a massage education program developed specifically for rural and remote palliative care workers. An 8 week pilot massage education course was run for palliative care workers in the Albury-Wodonga area and, from this course, an instructional video education package on massage has been developed. The program was evaluated by using a questionnaire, journals and focus group interviews. Feedback from participants was incorporated into both the pilot course and final education package, which was consistent with the action research framework. The major findings of the project were that skill development in the therapeutic use of massage was attained and that job satisfaction was indeed achieved by palliative care workers.

Attitude of Health Personnel↗
PubMed1998

Effects of diet and exercise in men and postmenopausal women with low levels of HDL cholesterol and high levels of LDL cholesterol.

BACKGROUND: Guidelines established by the National Cholesterol Education Program (NCEP) promote exercise and weight loss for the treatment of abnormal lipoprotein levels. Little is known, however, about the effects of exercise or the NCEP diet, which is moderately low in fat and cholesterol, in persons with lipoprotein levels that place them at high risk for coronary heart disease. METHODS: We studied plasma lipoprotein levels in 180 postmenopausal women, 45 through 64 years of age, and 197 men, 30 through 64 years of age, who had low high-density lipoprotein (HDL) cholesterol levels (< or =59 mg per deciliter in women and < or =44 mg per deciliter in men) and moderately elevated levels of low-density lipoprotein (LDL) cholesterol (>125 mg per deciliter but <210 mg per deciliter in women and >125 mg per deciliter but <190 mg per deciliter in men). The subjects were randomly assigned to aerobic exercise, the NCEP Step 2 diet, or diet plus exercise, or to a control group, which received no intervention. RESULTS: Dietary intake of fat and cholesterol decreased during the one-year study (P<0.001), as did body weight, in women and men in either the diet group or the diet-plus-exercise group, as compared with the controls (P<0.001) and the exercise group (P<0.05), in which dietary intake and body weight were unchanged. Changes in HDL cholesterol and triglyceride levels and the ratio of total to HDL cholesterol did not differ significantly among the treatment groups, for subjects of either sex. The serum level of LDL cholesterol was significantly reduced among women (a decrease of 14.5+/-22.2 mg per deciliter) and men (a decrease of 20.0+/-17.3 mg per deciliter) in the diet-plus-exercise group, as compared with the control group (women had a decrease of 2.5+/-16.6 mg per deciliter, P<0.05; men had a decrease of 4.6+/-21.1 mg per deciliter, P<0.001). The reduction in LDL cholesterol in men in the diet-plus-exercise group was also significant as compared with that among the men in the exercise group (3.6+/-18.8 mg per deciliter, P<0.001). In contrast, changes in LDL cholesterol levels were not significant among the women (a decrease of 7.3+/-18.9 mg per deciliter) or the men (10.8+/-18.8 mg per deciliter) in the diet group, as compared with the controls. CONCLUSIONS: The NCEP Step 2 diet failed to lower LDL cholesterol levels in men or women with high-risk lipoprotein levels who did not engage in aerobic exercise. This finding highlights the importance of physical activity in the treatment of elevated LDL cholesterol levels.

Adult↗
PubMed1998

Massage as a nursing intervention: using reflection to achieve change in practice.

The process of reflection can be used by nurse educators to more fully understand the nature of nursing practice and to actively use that understanding to bring about change through education. This paper documents a process of reflection carried out by a nurse educator within an action research project. The project was intended to assist palliative care nurses to learn the skill of massage and successfully integrate this therapy into their practice. Reflection takes place before the action to achieve change is implemented, in order to identify factors which will affect the development and implementation of the project. The reflection includes discussion of methodological issues, consideration of the influence of massage and holism in nursing practice and the influence of practice and institutional factors on palliative care nursing.

Health Services Research↗
PubMed1996

Simultaneous multipolar radiofrequency ablation in the monopolar mode increases lesion size.

Delivery of radiofrequency (RF) energy from the distal tip of electrophysiology catheters produces lesions that may be too small to ablate arrhythmogenic sites during a single application of RF energy. To produce larger lesions, we delivered RF energy via a quadripolar catheter in which all four electrodes were connected in unipolar fashion. The catheter (Webster Labs) had a 4-mm tip, 2-mm ring electrodes, and 2-mm interelectrode distance. Lesion size was compared using RF energy delivered in a multipolar configuration with that delivered only to the distal tip using fresh bovine ventricular tissue. In vivo, RF lesions were made in dogs using the distal tip as well as all four poles of the same catheter inserted percutaneously. RF energy was delivered using a constant voltage at a frequency of 400 kHz. Preliminary experiments were conducted to determine the maximum power deliverable without coagulation using each electrode configuration. The use of simultaneous multipolar RF ablation produced significantly larger lesions both in vitro and in vivo. The length of the lesion was increased by a factor of approximately 2 in both the in vitro and in vivo experiments. There was a trend toward an increasing depth of the lesion by simultaneously applying RF energy to all four electrodes. Lesion width was significantly increased in the in vivo studies. We concluded that simultaneous multipolar delivery of RF energy produces larger lesions than can be obtained with delivery of RF energy to the distal tip alone. This technique may offer a means of increasing lesion size, leading to a decrease in the number of applications of RF energy necessary for ablation of arrhythmias.

Animals↗
PubMed1996

Comparison of gold versus platinum electrodes on myocardial lesion size using radiofrequency energy.

During radiofrequency (RF) catheter ablation of arrhythmias, temperatures that approach 100 degrees C cause a coagulum to form on the ablation electrode that results in an increase in electrical impedance and prevents further energy delivery. Since gold has nearly four times the thermal conductivity as platinum, the metal commonly used, it was postulated that gold tip electrodes could deliver more power and produce deeper lesions because of its greater heat dissipation from the electrode-tissue interface to the circulating blood. To test this hypothesis, RF energy was applied to fresh bovine ventricular myocardium using 6 French catheters with 2-mm long distal electrodes made from gold or platinum. Similar studies were also conducted using 7 French catheters with 4-mm long distal electrodes. Maximum lesion depth was defined as that produced with the level of energy just below that causing an impedance rise. A maximum lesion depth of 6.2 +/- 0.7 mm (mean +/- SD) was obtained with the gold 2-mm electrode and 4.7 +/- 0.5 mm with the platinum electrode (P = 0.003). The 4-mm gold electrode produced a maximum lesion depth of 7.2 +/- 1.4 mm, while a catheter with a 4-mm platinum electrode caused a maximum lesion depth of 5.8 +/- 0.7 mm (P = 0.05). We conclude that deeper lesions should be able to be made when RF energy is delivered to a gold rather than platinum tip electrode.

Animals↗
PubMed1994

Regulation of protein kinase C by transforming growth factor beta 1 in rat costochondral chondrocyte cultures.

Transforming growth factor beta (TGF-beta) regulates the proliferation and differentiation of chondrocytes; however, the mechanism of TGF-beta signal transduction remains unclear. We examined whether the response to TGF-beta is mediated by protein kinase C activity in chondrocytes at different stages of maturation. The aims were to examine the effect of recombinant human TGF-beta 1 (rhTGF-beta 1) on protein kinase C in rat costochondral chondrocyte cultures; determine the major isoform present; assess the involvement of phospholipase C or tyrosine kinases; determine whether genomic or nongenomic pathways are involved; and test whether these mechanisms differ as a function of the stage of cell maturation. Dose-dependent increases in protein kinase C activity were observed in confluent, fourth-passage cultures of rat costochondral growth zone and resting zone chondrocytes treated with rhTGF-beta 1. In growth zone cells, elevated activity was observed at 12 h and decreased markedly by 24 h. In resting zone cells, elevated activity was observed at 9 h, maximum stimulation occurred at 12 h, and activity returned to baseline levels after 48 h. Immunoprecipitation studies showed protein kinase C alpha is the major isoform present in both untreated and treated cells. Neither the phospholipase C inhibitor, U73122, nor the tyrosine kinase inhibitor, genistein, significantly reduced the protein kinase C response to rhTGF-beta 1. Actinomycin D and cycloheximide, inhibitors of transcription and translation, produced dose-dependent inhibition of rhTGF-beta 1 stimulated protein kinase C activity in both resting zone and growth zone chondrocytes. The time course of activation and insensitivity to U73122 suggest that phospholipase C-mediated events are not involved in rhTGF-beta 1 stimulation of protein kinase C in costochondral chondrocytes. Similarly, because genistein had no effect, tyrosine kinases are not implicated. Rather, the reduction in protein kinase C activity observed when rhTGF-beta 1 is administered along with actinomycin D or cycloheximide indicates that new gene expression and protein synthesis are required for the response. These results indicate that the effect of rhTGF-beta 1 is mediated by protein kinase C; however, it is very slow and may require new protein kinase C production, perhaps via a cytokine cascade. Moreover, the classic mechanism of activation of protein kinase C by phospholipase C was not found, suggesting a novel mechanism of activation. Finally, the effects of rhTGF-beta 1 on protein kinase C are dependent on the state of cell maturation with respect to onset and duration of response.

Animals↗
PubMed1994

True Blue.

Explore the source record for details and available documents.

Drama↗
PubMed1993

Maturation-dependent regulation of protein kinase C activity by vitamin D3 metabolites in chondrocyte cultures.

Vitamin D3 metabolites regulate the differentiation of chondrocytes isolated from the growth zone or resting zone of rat costochondral cartilage. Since some of the direct membrane effects of vitamin D metabolites are nongenomic, we hypothesized that protein kinase C (PKC) plays a role in signal transduction for these chondrocyte differentiation factors and that the regulation of PKC by the vitamin D metabolites is cell maturation dependent. Confluent, fourth passage cultures of growth zone and resting zone chondrocytes were treated with vitamin D3 metabolites for up to 24 h, lysed, and cell extracts assayed for kinase activity using a specific PKC substrate peptide. The addition of 1,25-(OH)2D3 to growth zone cell cultures resulted in a rapid dose-dependent stimulation of PKC, significant at 10(-9)-10(-7) M, beginning at 3 min and sustained until 90 min; 1,25-(OH)2D3 had no effect on PKC activity in resting zone chondrocyte cultures. The addition of 24,25-(OH)2D3 to resting zone cultures showed a slower PKC activation, with significant stimulation seen at 90-360 min for 10(-8)-10(-7) M 24,25-(OH)2D3. However, 24,25-(OH)2D3 had no effect on PKC activity in growth zone cell cultures at all times and concentrations examined. The specificity of PKC stimulation by the vitamin D3 metabolites was verified using a specific pseudosubstrate region peptide inhibitor, which reduced PKC activity when included in the reaction mixture. Pretreatment of the cultures with U73, 122, a phospholipase C inhibitor, decreased 1,25-(OH)2D3-stimulated PKC activity but had no effect upon 24,25-(OH)2D3-induced activity. The tyrosine kinase inhibitor, genistein, did not inhibit the PKC response in either vitamin D3 metabolites-treated culture. Neither actinomycin D nor cycloheximide affected 1,25-(OH)2D3-induced PKC activity in growth zone chondrocyte cultures, while both compounds inhibited 24,25-(OH)2D3-induced activity in resting zone chondrocyte cultures. The results of this study indicate that vitamin D metabolites stimulate PKC activity in a metabolite- and cell-maturation-specific manner. Effects of 1,25-(OH)2D3 appear to be nongenomic, whereas the effects of 24,25-(OH)2D3 probably involve a genomic mechanism.

24,25-Dihydroxyvitamin D 3↗
PubMed1990

Desensitization of muscarinic M1 receptors of murine neuroblastoma cells (clone N1E-115) without receptor down-regulation and protein kinase C activity.

Acute desensitization of M1 muscarinic receptor-mediated responses (cyclic GMP formation and inositol phosphate release) was studied in murine neuroblastoma cells (N1E-115 clone). After a 45-min incubation at 37 degrees of N1E-115 cells either in monolayer or in suspension, with the muscarinic agonist carbachol (1 mM), the receptor-mediated cyclic GMP response to carbachol was nearly completely lost. This loss was associated with greater than 80% loss of carbachol-mediated inositol phosphate release. The protein kinase C activator phorbol 12-myristate 13-acetate (PMA) inhibited both responses with similar potencies. Carbachol or PMA reduced by 30-40% the number of muscarinic receptor sites for antagonist and agonist on intact cells (determined in binding assays using [3H]N-methylscopolamine) only for cells in monolayer and not for those in suspension. PMA but not carbachol pretreatment of cells in monolayer or in suspension caused a translocation of [3H]phorbol 12,13-dibutyrate binding and protein kinase C activity. In addition, desensitization to carbachol occurred in cells largely depleted of protein kinase C by chronic exposure to PMA. Thus, agonist-mediated down-regulation is not needed for muscarinic M1 receptor desensitization, which may be a result of the activation of a receptor-activated kinase different from protein kinase C.

Animals↗
PubMed1988

The effect of diet on plasma lipids, lipoproteins, and coronary heart disease.

The role that diet plays in the management of plasma lipid levels is discussed in this review. It has long been recognized that saturated fatty acids and cholesterol raise the plasma cholesterol level whereas polyunsaturated fatty acids lower it. Recently, the effects of other dietary constituents in the management of plasma lipid levels have been established. In particular, monounsaturated fatty acids, soluble fiber, and vegetarian diets favorably affect plasma lipid levels. Overweight and obesity adversely affect plasma lipid levels. Omega-3 fatty acids are hypotriglyceridemic, and high carbohydrate diets low in saturated fatty acids are hypocholesterolemic. Further work is required to establish the long-term consequences of alcohol and coffee consumption on the plasma lipid response. A variety of alternative dietary strategies can be employed in conjunction with traditional dietary recommendations (i.e., reduce total fat, especially saturated fatty acids and dietary cholesterol) for the management of plasma lipid levels. The expected plasma total cholesterol (specifically low-density-lipoprotein cholesterol) reduction is approximately 10% to 20% when dietary saturated fatty acids and cholesterol are decreased to less than or equal to 7% of calories and less than or equal to 200 mg of cholesterol per day. Further dietary modifications, such as increasing soluble fiber, may lead to additional reductions of 1% to 10% in plasma total cholesterol.

Alcohol Drinking↗