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Biomedical subjects

P Powers

Publications and source records attributed to P Powers.

At least 19 recordsLinked to original sources
PubMed2004

Nurses' clinical decision-making regarding the management of pain.

Effective pain management remains an elusive goal within the profession of nursing. While considerable improvement has occurred, patients continue to experience inappropriate levels of pain. To date, research has focused on objective factors that influence pain management. Few studies have examined attitudinal factors that may influence nurses' decision-making. This quasi-experiment was based on preliminary data showing that nurses' preconceived notions regarding certain patient groups influenced their management of pain. An intervention was tested for its' effect on nurses' preconceived notions regarding specific patient groups. A significant difference in a positive direction was found. Nurses were more willing to spend time and energy managing pain across all patient groups following the intervention.

Adult↗
PubMed2004

Nurses' clinical decision-making regarding the management of pain.

Effective pain management remains an elusive goal within the profession of nursing. While considerable improvement has occurred, patients continue to experience inappropriate levels of pain. To date, research has focused on objective factors that influence pain management. Few studies have examined attitudinal factors that may influence nurses' decision-making. This quasi-experiment was based on preliminary data showing that nurses' preconceived notions regarding certain patient groups influenced their management of pain. An intervention was tested for its' effect on nurses' preconceived notions regarding specific patient groups. A significant difference in a positive direction was found. Nurses were more willing to spend time and energy managing pain across all patient groups following the intervention.

Adult↗
PubMed2000

Establishing guidelines for pharmacotherapy trials in bulimia nervosa and anorexia nervosa.

OBJECTIVE: This paper addresses the lack of a standard protocol for pharmacotherapy trials for patients with bulimia nervosa (BN) and anorexia nervosa (AN). METHOD: Twenty-two surveys were sent to established researchers in the field of eating disorders to elicit their opinions regarding medication trials, including baseline laboratory tests, the optimal length/frequency of medication management sessions, and the information that should or should not be included in these sessions. RESULTS: Sixteen of 22 researchers completed and returned the survey. Their answers are the basis of the data presented. DISCUSSION: We propose a battery of screening laboratory tests for both conditions. We suggest 30-45-min initial medication management sessions in both AN and BN trials with 15-min follow-ups to be held weekly for AN subjects, and weekly for 2 weeks, then biweekly for 2 weeks, then monthly, for BN subjects. We also recommend that published trials should include explicit details of medication management.

Anorexia Nervosa↗
PubMed2000

A case of tuberculosis in Memphis.

The resurgence of tuberculosis has been of increasing concern to public health. Laryngeal and cutaneous tuberculosis have long been regarded as two of the most infectious forms of the disease. In this article, we re-emphasize the public health consequences of a case of laryngeal TB, which must be considered in the differential diagnosis of a patient with persistent fever, cough, weight loss, and hoarseness.

Adult↗
PubMed1999

Ca2+ sparks in embryonic mouse skeletal muscle selectively deficient in dihydropyridine receptor alpha1S or beta1a subunits.

Ca2+ sparks are miniature Ca2+ release events from the sarcoplasmic reticulum of muscle cells. We examined the kinetics of Ca2+ sparks in excitation-contraction uncoupled myotubes from mouse embryos lacking the beta1 subunit and mdg embryos lacking the alpha1S subunit of the dihydropyridine receptor. Ca2+ sparks occurred spontaneously without a preferential location in the myotube. Ca2+ sparks had a broad distribution of spatial and temporal dimensions with means much larger than those reported in adult muscle. In normal myotubes (n = 248 sparks), the peak fluorescence ratio, DeltaF/Fo, was 1.6 +/- 0.6 (mean +/- SD), the full spatial width at half-maximal fluorescence (FWHM) was 3.6 +/- 1.1 micrometer and the full duration of individual sparks, Deltat, was 145 +/- 64 ms. In beta-null myotubes (n = 284 sparks), DeltaF/Fo = 1.9 +/- 0.4, FWHM = 5.1 +/- 1.5 micrometer, and Deltat = 168 +/- 43 ms. In mdg myotubes (n = 426 sparks), DeltaF/Fo = 1 +/- 0.5, the FWHM = 2.5 +/- 1.1 micrometer, and Deltat = 97 +/- 50 ms. Thus, Ca2+ sparks in mdg myotubes were significantly dimmer, smaller, and briefer than Ca2+ sparks in normal or beta-deficient myotubes. In all cell types, the frequency of sparks, DeltaF/Fo, and FWHM were gradually decreased by tetracaine and increased by caffeine. Both results confirmed that Ca2+ sparks of resting embryonic muscle originated from spontaneous openings of ryanodine receptor channels. We conclude that dihydropyridine receptor alpha1S and beta1 subunits participate in the control of Ca2+ sparks in embryonic skeletal muscle. However, excitation-contraction coupling is not essential for Ca2+ spark formation in these cells.

Animals↗
PubMed1997

Body composition and source of weight loss after bariatric surgery.

BACKGROUND: Little is known about the composition and source of weight loss after bariatric surgery for morbid obesity. PURPOSE: This study was undertaken to determine changes in weight, body mass index (BMI), lean body weight (LBW), fat weight (FW) and left ventricular cardiac mass (LVM) following vertical banded gastroplasty (VBG). METHODS: After VBG for morbid obesity, 26 women and four men (mean age = 39.1 years) were weighed and had body composition analysis undertaken at intervals. Thirteen patients underwent echocardiography preoperatively and 1 year postoperatively to determine change in LVM and LVM index. RESULTS: Over 12 months there was significant weight loss for all weight parameters examined (p < 0.05). Fat weight loss was most significant; total weight loss and reduction of BMI were significant but less so than fat loss (Wilcoxon's signed ranks test). LBW loss had the smallest contribution to weight loss (p < 0.0001). There was a significant loss of LVM and posterior cardiac wall thickness (p < 0.05). CONCLUSIONS: VBG can lead to loss of lean body weight and left ventricular mass, and more dramatically, fat weight, body weight, and BMI. Cardiac mass and lean body mass are preferentially conserved relative to body fat with weight loss after VBG.

Adult↗
PubMed1996

Ardeparin (low-molecular-weight heparin) vs graduated compression stockings for the prevention of venous thromboembolism. A randomized trial in patients undergoing knee surgery.

BACKGROUND: Deep vein thrombosis is common in patients undergoing major knee surgery. Static graduated compression stockings effectively prevent venous thrombosis in general surgery. Because of the demonstrated prophylactic efficacy of pneumatic compression in knee surgery, the similar efficacy of static graduated compression and pneumatic compression in neurosurgery, and the easier use of static graduated compression in knee surgery, graduated static compression stockings were used as the control arm in our clinical trial. Although low-molecular-weight heparin had been shown to be effective in general surgery and hip replacement, its efficacy was unproved in knee surgery. METHODS: A double-blind, randomized trial compared the combination of low-molecular-weight heparin and graduated compression stockings with graduated compression stockings alone in patients undergoing major knee surgery. Patients received either ardeparin (Normiflo) (low-molecular-weight heparin), 0.005 mL/kg (50 anti-Xa U/Kg), or placebo. Both were administered subcutaneously twice daily commencing 12 to 24 hours after surgery and continued for 14 days or until discharge, if sooner. Both study groups wore graduated compression stockings. Bilateral venography was performed on day 14, or sooner if the patient was ready for discharge. RESULTS: One hundred twenty-two patients were allocated to receive ardeparin and 124 received placebo. Ninety-six patients in the ardeparin group and 103 in the placebo group had evaluable venograms. Deep vein thrombosis was detected in 28 patients in the ardeparin group and in 60 in the placebo group. Proximal deep vein thrombosis was detected in two patients who received ardeparin and 16 who received placebo. One patient in each group, both of whom did not have venography, experienced pulmonary embolism. Thus, deep vein thrombosis or pulmonary embolism was detected in 29 (29.9%) of the 97 patients in the ardeparin group and in 61 (58.7%) of the 104 patients in the placebo group, a relative risk reduction of 49% (P < 00.1). The rate of major bleeding in the ardeparin group was 2.5%, compared with 2.4% in the placebo group. CONCLUSION: Ardeparin administered postoperatively twice daily is effective and safe for the prevention of venous thrombosis in patients undergoing major knee surgery. Whereas graduated compression stockings have been shown to be effective prophylactic agents in general surgery and neurosurgery, they have little effect in knee surgery.

Aged↗
PubMed1996

Stable isotope model for assessing production of short chain fatty acids from colon-derived sugar: application in pigs.

Sugar reaching the colon because of intestinal maldigestion or malabsorption may be fermented to acetate and other short-chain fatty acids, resulting in stimulation of colonic water absorption and cell proliferation. To explore this phenomenon in more detail, we have developed a stable isotope model for estimating the fraction of colon-derived glucose or lactose that is fermented to acetate, propionate and butyrate. In an initial application of the model, [d3]-acetate and either [1-(13)C]-glucose or [D-1-(13)C]-lactose were infused into the cecum or colon of piglets, and plateau plasma acetate enrichment was monitored in the carotid artery. In acutely anesthetized piglets, the fractions of glucose and lactose fermented to acetate were 17.0 and 20.0%, respectively. In a chronically catheterized piglet, fermentation was higher (34.2%). When conducted in chronically catheterized animals or via a colostomy or ileostomy in infants, this model may be used to determine how age, previous surgery or antibiotic therapy affects the efficiency of colonic assimilation of carbohydrate.

Acetates↗
PubMed1996

Discourse analysis as a methodology for nursing inquiry.

Discourse analysis is a relatively recent form of inquiry without a strict step-by-step method. The methodology of discourse analysis has a longer history in Continental Europe than in other countries. The complex theoretical assumptions, the goals and the target (discourse) have been explicated, but the methodology may be applied in different ways. This paper will describe discourse analysis and give examples of some of the possible variations. It is the claim of this paper that discourse analysis deserves consideration as a methodology for nursing inquiry.

Female↗
PubMed1996

Galactose-containing carbohydrates are preferentially absorbed in the neonatal pig colon.

Previous studies on the piglet colon in newborns cleared of bacterial metabolic activity showed a capacity for lactose absorption. Colonic absorption occurred at a flux rate equal to the assimilation of lactose by the small intestine but by a process that did not involve either glucose-galactose sodium cotransport or simple diffusion. Surprisingly, colonic lactose transport did not require either fermentation or cleavage of the disaccharide for uptake. Experiments were designed to test the selectivity of the colonic transport process for a variety of carbohydrates. Colonic tissues from 4-7-d-old piglets were mounted in Ussing chambers and the mucosal-to-serosal flux of radiolabeled carbohydrates was compared with that of lactose. The results showed a 3-4-fold greater flux of galactose-containing sugars as compared with glucose-containing carbohydrates at concentrations up to 40 mM. Even lactulose, a synthetic disaccharide assumed to require bacterial digestion before assimilation, was transported readily. N-Acetylgalactosamine, a component of colonic mucus, inhibited the flux of lactose, whereas N-acetylglucosamine did not. Similarly, lactosylated BSA inhibited lactose flux, whereas nonlactosylated BSA did not. The capacity of the colon of the newborn to differentiate moieties as similar as glucose and galactose suggests an absorptive process for carbohydrates with a high degree of discrimination.

Animals↗
PubMed1995

Inadequacy of intravenous heparin therapy in the initial management of venous thromboembolism.

To determine the adequacy of initial anticoagulation by intravenous heparin for patients who have deep venous thrombosis (DVT), and the factors that influence delayed anticoagulation, independent, duplicate chart review of 63 consecutive patients who had venography-proven DVT was conducted. Adequate heparinization (AH) was defined as an activated partial thromboplastin time (PTT) of more than 1.5 times the normal laboratory control. The proportions of patients achieving AH within 24 hours and 48 hours of initial heparin bolus were 46% and 62%, respectively. Patients who weighed more were less likely to achieve AH (p < 0.05), while patients receiving care from the thromboembolism service were more likely to achieve AH (p < 0.05). Low initial infusion rate was strongly but not significantly predictive of inadequate anticoagulation (p = 0.06). The mean heparin bolus and initial infusion rates were significantly lower than those suggested in the literature (p < 0.01). The AH rates were comparable to historical controls but suboptimal compared with the rates of 66% at 24 hours and 81% at 48 hours reported in association with heparin nomogram use (p < 0.05). A heparin nomogram is likely to achieve consistently higher rates of adequate heparinization.

Aged↗
PubMed1995

Heart transplantation in an 8-month-old girl. 10th anniversary report.

In 1984, Dr. Denton A. Cooley led a surgical team that implanted a cardiac allograft in an 8-month-old girl who had end-stage cardiac disease secondary to endocardial fibroelastosis. At that time, experience with cardiac transplantation in infants was limited, and the long-term effects of the procedure were cause for concern. Ten years later, our patient is a healthy 4th-grade student who enjoys a remarkably normal life. She has grown and developed quite satisfactorily, and her heart has enlarged in proportion to her overall somatic growth. Long-term immunosuppression has produced no adverse effects, and the child's medical problems have differed little from those of her peers. This landmark case has yielded preliminary answers to a number of important questions about cardiac transplantation in infants and has confirmed our original opinion that the procedure is well warranted in selected patients.

Child↗
PubMed1995

Optimal duration of oral anticoagulant therapy: a randomized trial comparing four weeks with three months of warfarin in patients with proximal deep vein thrombosis.

The optimal duration of oral anticoagulant therapy for patients with acute proximal deep vein thrombosis (DVT) is uncertain. Based on the hypothesis that a normal impedance plethysmogram (IPG) following DVT defines a group of patients at low risk of recurrent venous thromboembolism (VTE), a trial was conducted to evaluate the efficacy of only four weeks of warfarin. Patients with venographically confirmed acute proximal DVT who had received four weeks of warfarin after initial heparin and whose four week IPG was normal were allocated to either continue warfarin (targeted International Normalized Ratio 2.0 to 3.0) for a further eight weeks or receive placebo. Patients with an abnormal four week IPG received warfarin for a further eight weeks. Based on clinical characteristics at the time of the qualifying thrombosis, all patients were classified as having either continuing or transient risk factors for recurrent VTE. During the eight weeks following randomization, nine (8.6%) of the 105 placebo patients developed recurrent VTE compared to one (0.9%) of the 109 warfarin patients, P = 0.009. Over the entire 11 months of follow-up, 12 placebo patients developed recurrence compared to seven warfarin patients, P = 0.3. Nineteen of the 192 patients with an abnormal four week IPG experienced recurrence during the nine months after discontinuing warfarin. In the 301 patients who received three months of warfarin in the randomized trial or in the cohort study, all 26 recurrent events were in the 212 patients with continuing risk factors.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

The evaluation of a cell dispersion method of sputum examination.

In recent studies, sputum smear cell counts were found to be reproducible and usefully applied to research in asthma and other airway conditions. However, cell definition on the smears is poor, and the procedure is tedious and has limited utility. The objective of this study is to improve the methods of sputum examination. The subjects used in this study were people with bronchitis or asthma from whom sputum could be obtained. By inverted microscopy, portions of fresh sputum were selected to exclude salivary contamination. These portions were exposed to different volumes of dithiothreitol for varied time intervals. We used the resulting cell suspensions to perform total cell counts and prepare cytospins for differential cell counts and immunohistochemical stains for GM-CSF, EG2, TNF alpha and IL-8. Cytospins were compared with smears for differential cell counts on the same sputum specimens. Excellent cell dispersion and definition in cytospins could be observed. The time required for differential cell counting on cytospins was reduced and cytospin counts were more reproducible than smears. Greater duration of treatment of sputum with dithiothreitol tended to increase total cell counts and significantly decreased EG2 staining but had no effect on differential cell counts or the cytokine cell components. Therefore the proposed method of sputum examination involving cell dispersion and use of cytospins overcomes a number of the disadvantages of the examination of smears.

Cell Count↗
PubMed1994

Use of Hirulog in the prevention of venous thrombosis after major hip or knee surgery.

BACKGROUND: The study objective was to determine whether Hirulog, a direct thrombin inhibitor, has potential efficacy and safety in the prevention of deep vein thrombosis (DVT) in orthopedic patients. A phase 2 open-label, dose-escalating design was used to study 222 unselected patients undergoing major hip or knee surgery in tertiary-care, university-affiliated hospitals. METHODS AND RESULTS: Subcutaneous Hirulog was initiated postoperatively. Patients were evaluated for bleeding and symptomatic pulmonary embolism, and mandatory bilateral venography was performed before discharge. Dose escalations were made on the basis of observed rates of bleeding and venous thrombosis. There were five dosage regimens used: 0.3 mg/kg every 12 hours, 0.6 mg/kg every 12 hours, 1.0 mg/kg every 12 hours for 3 days followed by 0.6 mg/kg every 12 hours for up to 11 days, 1.0 mg/kg every 12 hours, and 1.0 mg/kg every 8 hours. One hundred seventy-seven patients who had technically adequate bilateral venography or objectively documented pulmonary embolism were included in the primary analysis of efficacy. The highest dosage regimen (1.0 mg/kg every 8 hours) provided the lowest rates of total DVT (17%) and proximal DVT (2%), both of which were significantly lower (P = .010 and P = .023, respectively) than the pooled rates of total (43%) and proximal (20%) DVT seen with the first four regimens. Bleeding rates were low (< 5%) with all regimens. CONCLUSIONS: This study demonstrates that 1.0 mg/kg Hirulog every 8 hours started postoperatively is potentially efficacious and safe for the prevention of DVT after major hip or knee surgery.

Aged↗
PubMed1993

Exclusion of malignant hyperthermia susceptibility (MHS) from a putative MHS2 locus on chromosome 17q and of the alpha 1, beta 1, and gamma subunits of the dihydropyridine receptor calcium channel as candidates for the molecular defect.

Malignant hyperthermia (MH) is a potentially lethal pharmacogenetic disease with autosomal dominant inheritance triggered by exposure to commonly used inhalational anaesthetics or depolarising muscle relaxants. A MHS locus has been identified on human chromosome 19q12-q13.2 and the gene for the skeletal muscle calcium release channel of sarcoplasmic reticulum (ryanodine receptor) (RYR1) is considered a candidate for the molecular defect. However, MH has been shown to be genetically heterogeneous, and in the ensuing search for other MHS genes, a locus on chromosome 17q has been proposed, and the gene for the adult muscle sodium channel (SCN4A) was suggested as a candidate. We performed linkage studies using polymorphic microsatellite markers for subunits of the skeletal muscle dihydropyridine (DHP) receptor, CACNL1A3 mapped to chromosome 1q, as well as C-ACNLB1 and CACNLG, the latter two localised on chromosome 17q11.2-q24 in proximity to the proposed MHS2 and the SCN4A loci, and we also included markers for the loci D17S250, D17S579, NM23 (NME1), GH1, and SCN4A from that region. Our results exclude the alpha 1, beta 1 and gamma subunit of the DHP receptor as well as the SCN4A locus from that region. Our results exclude the alpha 1, beta 1, and gamma subunit of the DHP receptor as well as the SCN4A locus as candidates for the molecular defect in MHS for these pedigrees where also the RYR1 on chromosome 19q13.1 has been excluded. A multipoint analysis excludes the disease from the entire 84 cM interval containing the proposed MHS locus on chromosome 17q.(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗
PubMed1991

Primary structure of the goat beta-globin locus control region.

The goat beta-globin cluster is composed of a triplicated four-gene set. A locus control region (LCR) containing elements homologous to 5'DNase I hypersensitive sites (HS) 1, 2, and 3 of the human beta-globin LCR has been identified at the 5' end of this locus. We determined 10.2 kb of nucleotide sequence from the goat beta-globin locus control region. Self-comparison of this sequence by dot matrix analysis revealed the presence of six complete and three incomplete artiodactyl repeats. A novel repeated element, termed D repeat, was also identified. Southern blotting analysis demonstrated that these elements exist in the goat genome as a low to medium frequency interspersed repeat family. The absence of any other large region of self-homology (direct or inverted) in the goat LCR suggests that 5'HSs 1, 2, and 3 did not arise through duplication, but rather evolved independently. By comparing goat 5'HS 1 to those of human, rabbit, and mouse, we show a greater than 80% conservation in sequence between the four species. This level of evolutionary conservation suggests that 5'HS 1 plays an important role in the regulation of beta-globin loci.

Animals↗