Biomedical subjects

S Wheeler

Publications and source records attributed to S Wheeler.

At least 19 recordsLinked to original sources

PubMed2006

Communication of HIV viral load to guide sexual risk decisions with serodiscordant partners among San Francisco men who have sex with men.

The objective of this study was to estimate frequency and correlates of discussing HIV viral load (VL) with serodiscordant sex partners to guide decisions about sexual activities among men who have sex with men (MSM). We conducted a cross-sectional survey of 573 San Francisco MSM. Among 507 who knew their HIV status, 397 (78%) were familiar with the term 'viral load', and half (n=199) had a serodiscordant partner in the prior year. These 199 respondents (n=130 [65%] HIV-positive; n=69 [35%] HIV-negative) were the focus of this analysis. A majority (n=111, 56%) discussed VL in the prior year with serodiscordant partners specifically to guide decisions about sexual risk behaviour. Discussion was more common among HIV-positive than HIV-negative participants (adjusted odds ratio [AOR], 3.5; 95% confidence interval [CI], 1.6-7.6), and African Americans compared to whites (AOR, 3.7; 95% CI, 1.5-9.5). HIV-negative men who discussed VL were more concerned about becoming infected, but also more willing to engage in risky behaviour with a partner whose VL is undetectable, than men not discussing VL. Some HIV-negative men may be discussing VL to engage in higher risk behaviour upon learning of an HIV-positive partner's undetectable VL. Interventions targeting MSM should explain that while risk of transmission is likely reduced with a low blood plasma VL, it is not necessarily eliminated.

Adult↗

PubMed2003

Paclitaxel plus platinum-based chemotherapy versus conventional platinum-based chemotherapy in women with relapsed ovarian cancer: the ICON4/AGO-OVAR-2.2 trial.

BACKGROUND: Despite improvements in the treatment of ovarian cancer, most patients develop recurrent disease within 3 years of diagnosis. There is no agreed second-line treatment at relapse. We assessed paclitaxel plus platinum chemotherapy as such treatment. METHODS: In parallel international, multicentre, randomised trials, between January, 1996, and March, 2002, 802 patients with platinum-sensitive ovarian cancer relapsing after 6 months of being treatment-free were enrolled from 119 hospitals in five countries. Patients were randomly assigned paclitaxel plus platinum chemotherapy or conventional platinum-based chemotherapy. Analysis was by intention to treat, except for toxic effects. FINDINGS: With a median follow-up of 42 months, 530 patients have died. Survival curves showed a difference in favour of paclitaxel plus platinum (hazard ratio 0.82 [95% CI 0.69-0.97], p=0.02), corresponding to an absolute difference in 2-year survival of 7% between the paclitaxel and conventional treatment groups (57 vs 50% [95% CI for difference 1-12]), and median survival of 5 months (29 vs 24 months [1-11). 717 patients developed progressive disease or died. The progression-free survival curves show a difference in favour of paclitaxel plus platinum (hazard ratio 0.76 [0.66-0.89], p=0.0004), corresponding to an absolute difference in 1-year progression-free survival of 10% (50 vs 40% [4-15]) and in median progression-free survival of 3 months (13 vs 10 months [1-5]). INTERPRETATION: Paclitaxel plus platinum chemotherapy seems to improve survival and progression-free survival among patients with relapsed platinum-sensitive ovarian cancer compared with conventional platinum-based chemotherapy.

Aged↗

PubMed2003

Stochastic resonance on two-dimensional arrays of bistable oscillators in a nonlinear optical system.

We describe an experimental realization of stochastic resonance in two-dimensional arrays of coupled nonlinear oscillators. The experiment is implemented using an optoelectronic system composed of a liquid crystal light valve in a feedback loop with external, spatially variable noise being added through a liquid crystal display. The behavior of the system differs from previously studied uniform arrays, showing a high signal-to-noise ratio at the output for a broad range of input noise. We show that this behavior is qualitatively the same as that exhibited by computer models where the nonlinear elements of the array have a distribution of biases applied to their switching thresholds.

Journal Article↗

PubMed2002

Absorption of biologically active peptide hormones from the small intestine of rat.

Absorption of the 4, 10 and 34 amino acid forms of gastrin from the small intestine has been investigated in anaesthetized rats. The method of assessment of successful absorption of the hormone into the systemic circulation was when the amount of acid secreted by the stomach over consecutive 15-min periods was increased. When the natural hormones were infused into the ileum in a relatively high dose, there was no increase in gastric acid secretion, indicating that they had not been absorbed. Each of the forms of gastrin was conjugated at the free amino terminus to the carboxyl group of cholic acid. Subsequent infusion of the conjugated form of gastrin into the ileum, this time in relatively low doses, resulted in substantial and prolonged increases in gastric acid secretion, indicating that these hormones had been successfully absorbed. In addition, conjugation of the 10 and 34 amino acid forms of gastrin with cholic acid was shown to increase markedly the potency in evoking an increase in gastric acid secretion in response to intravenous injection of the hormone. Absorption of the gastrin conjugates was specific to the ileum thus indicating that they had been absorbed through the bile salt transporters.

Absorption↗

PubMed2001

Combining speech recognition software with Digital Imaging and Communications in Medicine (DICOM) workstation software on a Microsoft Windows platform.

This presentation describes our experience in combining speech recognition software, clinical review software, and other software products on a single computer. Different processor speeds, random access memory (RAM), and computer costs were evaluated. We found that combining continuous speech recognition software with Digital Imaging and Communications in Medicine (DICOM) workstation software on the same platform is feasible and can lead to substantial savings of hardware cost. This combination optimizes use of limited workspace and can improve radiology workflow.

Humans↗

PubMed2001

The complementarity of phenomenology, hermeneutics and existentialism as a philosophical perspective for nursing research.

The focus of this paper draws on the thinking of Husserl, Dilthey and Heidegger to identify elements of the phenomenological movement that can provide focus and direction for qualitative research in nursing. The authors interpret this tradition in two ways: emphasizing the possible complementarity of phenomenology, hermeneutics and existentialism, and demonstrating how these emphases ask for grounding, reflexivity and humanization in qualitative research. The paper shows that the themes of grounding, reflexivity and humanization are particularly important for nursing research.

Data Collection↗

PubMed2001

Efficacy and safety of oral sildenafil in men with erectile dysfunction and spinal cord injury.

OBJECTIVE: To assess the efficacy of sildenafil in men with spinal cord injury (SCI) and erectile dysfunction (ED). METHODS: Seventeen men with SCI were selected from February to September 1998 for sildenafil treatment of ED. The initial dose of 25 mg was increased by 25-mg increments as needed. Patients underwent baseline physical examination and answered questions from the abridged International Index of Erectile Function before and during therapy. RESULTS: Sixteen patients tolerated therapy; 1 developed hypotension and discontinued therapy. There was significant improvement in erectile function (P < .05) after 5.3 +/- 2.2 months when compared with baseline or previous therapies (P < .05). Of the 17 patients, 94% recommended sildenafil to others. Six of these 16 patients were available for long-term follow-up. There was further significant improvement in quality of erection (P < .05), but no change in satisfaction. CONCLUSION: Sildenafil is effective and well tolerated in men with SCI and ED.

Administration, Oral↗

PubMed2000

Telephone triage: SAVED by the form.

Explore the source record for details and available documents.

Abbreviations as Topic↗

PubMed1999

Denial: a conceptual analysis.

The term denial is used in nursing to describe a client's behavior. A random sample of 18 articles published in English from 1990 to 1999 was identified for conceptual analysis using Rogers' methodology. The 2 main definitions identified ranged from an adaptive to maladaptive coping process. Anxiety or perceived threats evolving from situational or maturational crises were antecedents. Events that followed typically resulted in either positive or negative outcomes. Related concepts used most often were avoidance, unrealistic hopefulness, and repression.

Adaptation, Psychological↗

PubMed1999

Epilepsy and religious experiences: Voodoo possession.

Epileptic seizures have a historical association with religion, primarily through the concept of spirit possession. Five cases where epileptic seizures were initially attributed to Voodoo spirit possession are presented. The attribution is discussed within the context of the Voodoo belief system.

Adult↗

PubMed1999

Once-weekly resistance exercise improves muscle strength and neuromuscular performance in older adults.

OBJECTIVE: To determine the effect of frequency of resistive training on gain in muscle strength and neuromuscular performance in healthy older adults. DESIGN: A randomized controlled trial with subjects assigned either to high-intensity resistance training 1 (EX1), 2 (EX2), or 3 (EX3) days per week for 24 weeks or to a control group (CO). SETTING: An exercise facility at an academic medical center. SUBJECTS: Forty-six community-dwelling healthy men (n = 29) and women (n = 17) aged 65 to 79 years. INTERVENTION: Progressive resistance training consisting of three sets of eight exercises targeting major muscle groups of the upper and lower body, at 80% of one-repetition maximum (1-RM) for eight repetitions, either 1, 2, or 3 days per week. MEASURES: Dynamic muscle strength (1-RM) using isotonic equipment every 4 weeks, bone mineral density and body composition by dual energy X-ray absorptiometry (DXA), and neuromuscular performance by timed chair rise and 6-meter backward tandem walk. RESULTS: For each of the eight exercises, muscle strength increased in the exercise groups relative to CO (P < .01), with no difference among EX1, EX2 and EX3 groups at any measurement interval. Percent change averaged 3.9 +/- 2.4 (CO), 37.0 +/- 15.2 (EX1), 41.9 +/- 18.2 (EX2), and 39.7 +/- 9.8 (EX3). The time to rise successfully from the chair 5 times decreased significantly (P < .01) at 24 weeks, whereas improvement in the 6-meter backward tandem walk approached significance (P = .10) in the three exercise groups compared with CO. Changes in chair rise ability were correlated to percent changes in quadriceps strength (r = -0.40, P < .01) and lean mass (r = -0.40, P < .01). CONCLUSIONS: A program of once or twice weekly resistance exercise achieves muscle strength gains similar to 3 days per week training in older adults and is associated with improved neuromuscular performance. Such improvement could potentially reduce the risk of falls and fracture in older adults.

Absorptiometry, Photon↗

PubMed1999

Rapid disappearance of zaleplon from breast milk after oral administration to lactating women.

Five lactating mothers were administered the therapeutic dose of zaleplon (10 mg) orally in an open-label, single-dose, pharmacokinetic study. Plasma and breast milk were sampled through 8 hours after dose administration for subsequent determinations of zaleplon and its major, though inactive, plasma metabolite 5-oxo-zaleplon. Zaleplon concentrations peaked in plasma and milk approximately 1 hour after dosing and then disappeared rapidly. The mean terminal half-life was slightly greater than 1 hour. Milk concentrations "mirrored" plasma concentrations closely with no discernible delay between peak times. The average milk-to-plasma (M/P) concentration ratio for zaleplon was approximately 0.50 over the time course. 5-oxo-zaleplon was undetectable in all but one milk sample. The maximum exposure of an infant to zaleplon during a feeding at peak milk concentrations was estimated to range from 1.28 micrograms to 1.66 micrograms, corresponding to 0.013% to 0.017% of the maternal dose or 0.320 microgram/kg to 0.415 microgram/kg for a 4 kg infant. The results indicate that zaleplon taken by a nursing mother is transferred through breast milk to her infant in very small quantities that are unlikely to be clinically important.

Acetamides↗

PubMed1998

A case series of 71 patients referred to a hospital-based occupational and environmental medicine clinic for occupational asthma.

In a ten-year period at the Occupational and Environmental Medicine Program (OEMP) of the University of Washington in Seattle, 71 patients were determined by attending physicians to have work-related asthma. In this cross-sectional descriptive study, we describe these patients. Data were obtained from a database maintained by the OEMP and from chart reviews. We found that the three most common specific agents causing asthma were isocyanates, red cedar, and crabs. At least one pulmonary function study was available for all patients and was positive in 56 patients (79%). Among the 71 asthma cases reported in this article, 18 (25%) were attributed to reactive airways dysfunction syndrome (RADS); 19 (27%) to exacerbation of pre-existing asthma; 27 (38%) to sensitization; and 7 (10%) had undetermined causes. We conclude that occupational asthma presents as a result of diverse exposures in multiple work settings and with an array of characteristics. Prevention efforts need to recognize this diversity.

Adult↗

PubMed1997

Prevention of central venous catheter-related bloodstream infection by use of an antiseptic-impregnated catheter. A randomized, controlled trial.

BACKGROUND: Bloodstream infection related to short-term use of noncuffed central venous catheters is a common and serious problem. Technologic innovations to reduce the risk for these infections are needed. OBJECTIVE: To determine 1) the efficacy of a novel antiseptic catheter in preventing central venous catheter-related infection, 2) patient tolerance of this catheter, and 3) the sources of bloodstream infection originating from noncuffed, multilumen central venous catheters. DESIGN: Randomized, controlled clinical trial. SETTING: Medical-surgical intensive care unit of a 450-bed university hospital. PARTICIPANTS: 158 adults scheduled to receive a central venous catheter; 403 catheters were studied. INTERVENTION: Participants received either a standard triple-lumen polyurethane catheter or a catheter that was indistinguishable from the standard catheter and was impregnated with chlorhexidine and silver sulfadiazine. MEASUREMENTS: Catheters were studied for colonization and catheter-related bloodstream infection at removal; local and systemic effects of catheters were assessed. The origin of each catheter-associated bloodstream infection was sought by culturing all potential sources (skin, catheter segments, hubs, and infusate) and confirmed by restriction-fragment DNA subtyping. RESULTS: Antiseptic catheters were less likely to be colonized at removal than control catheters (13.5 compared with 24.1 colonized catheters per 100 catheters; relative risk, 0.56 [95% CI, 0.36 to 0.89]; P = 0.005) and were nearly fivefold less likely to produce bloodstream infection (1.0 compared with 4.7 infections per 100 catheters; 1.6 compared with 7.6 infections per 1000 catheter-days; relative risk, 0.21 [CI, 0.03 to 0.95]; P = 0.03). In the control group, 8 catheter-related bloodstream infections were caused by Staphylococcus aureus, gram-negative bacilli, enterococci, or Candida species; no infections with these organisms occurred in the antiseptic catheter group (P = 0.003). No adverse effects from the antiseptic catheter were seen, and none of the 122 isolates obtained from infected catheters in either group showed in vitro resistance to chlorhexidine-silver sulfadiazine. Cost-benefit analysis indicated that the antiseptic catheter should prove cost-beneficial if an institution's rate of catheter-related bacteremia with noncuffed central venous catheters is at least 3 infections per 1000 catheter-days). CONCLUSIONS: The chlorhexidine-silver sulfadiazine catheter is well tolerated, reduces the incidence of catheter-related infection, extends the time that noncuffed central venous catheters can be safely left in place for the short term, and should allow cost savings.

Adult↗

PubMed1997

Direct preparation of cyclodextrin monophosphates.

Aqueous solutions of cyclodextrins and inorganic metaphosphate at pH 4, upon drying and subsequent warming, produce mixtures of isomeric monophosphate esters which are amenable to separation by anion-exchange chromatography. The products are characterised by enzymatic, mass, and NMR spectroscopic analysis. The methodology provides a route to these derivatives by a single reaction.

Carbohydrate Sequence↗

PubMed1997

Suitability of bone marrow from HIV-1-infected donors for retrovirus-mediated gene transfer.

Bone marrow samples from 21 human immunodeficiency virus type 1 (HIV-1)-infected subjects were evaluated for their suitability for retrovirus-mediated gene transduction with anti-HIV-1 genes. The percentages of CD34+ cells that could be isolated from the mononuclear fraction of bone marrow samples were determined. Fifteen of the 21 marrow samples had normal percentages of CD34+ cells isolated by immunomagnetic methods. All seven donors with CD4 counts > 100/mm3 had normal percentages of CD34+ cells; of 14 patients with low CD4 cell counts (< 100/mm3), 5 had reduced and 9 had normal percentages of CD34+ cells. Samples of the marrow were plated in a methylcellulose colony-forming unit (CFU) assay to determine the clonogenic capacity of the progenitor cells. Overall, the marrow samples from HIV-infected donors showed a 44% reduction in CFU derived from the mononuclear cell fraction and a 75% reduction in CFU derived from the isolated CD34+ cell fraction, when compared to marrow samples from uninfected donors. Isolated CD3+ cells were transduced with retroviral vectors containing various anti-HIV-1 genes to determine their susceptibility to gene transfer. Transduction of the clonogenic CD34+ cells by retroviral vectors did not differ among marrow samples from 13 HIV-1+ donors and 9 uninfected donors. Long-term bone marrow cultures established from the transduced CD34+ cells demonstrated equivalent survival of clonogenic progenitor cells from both HIV-1-infected and uninfected marrows. Toxicity from expression of the anti-HIV-1 genes was not observed; the percentages of clonogenic progenitor cells that survived in cultures transduced by vectors carrying anti-HIV-1 genes were similar to those transduced by the control LN vectors. Stromal cells cultured from marrow samples from HIV-1-infected donors showed similar growth kinetics, hematopoietic support function, and enhancement of retrovirus-mediated transduction of CD34+ cells as seen with stromal cells cultured from uninfected marrow donors. Semi-quantitative polymerase chain reaction (PCR) was performed before and after ex vivo transduction to determine the frequency of HIV-1-containing cells in the CD34+ cell preparations. Although HIV-1+ cells were present at low levels in the mononuclear cell fractions of some of the marrow samples, the CD34+ cell preparation from only one marrow sample contained detectable HIV-1 positive cells (< 1 positive cell/100,000 by PCR) prior to transduction. None of the CD34+ cell preparations contained detectable HIV-1 after transduction. These studies demonstrate that HIV-1-infected patients are candidates for retrovirus-mediated transduction of anti-HIV-1 genes in bone marrow gene therapy clinical trials.

Adolescent↗

PubMed1997

An investigation into the relative merits of pituitary adenylate cyclase-activating polypeptide (PACAP-27) and vasoactive intestinal polypeptide as vagal neuro-transmitters in exocrine pancreas of rats.

Pancreatic exocrine secretions were collected over 15 min periods and analysed in terms of weight of juice, total HCO3- and total protein in anaesthetized and pithed rats. Pituitary adenylate cyclase-activating polypeptide (PACAP) (i.v.) evoked a serous HCO3- secretion which contained relatively little protein, together with a marked vasodepressor action. The latter was still maximal at lower doses of PACAP, which evoked diminished pancreatic secretions. The effects of PACAP were similar to those evoked by the same dose of VIP and by cervical vagal stimulation, while secretion evoked a much larger secretion of fluid and HCO3-. The time courses of the PACAP-evoked secretions were significantly delayed compared with those of VIP. In the pithed rat, PACAP caused the same level of pancreatic secretions as in the anaesthetized rat, though this was now accompanied by a substantial pressor response which was blocked by phentolamine or prazosin, indicating that it was alpha 1-adrenoceptor mediated. VIP caused a depressor response in the pithed rat, as well as the same level of pancreatic secretions as in the anaesthetized rat. The putative VIP antagonist [Lys1,Pro25,Arg3,4,Tyr6]-VIP (abbreviated as VIPi) caused a selective and significant reduction in the HCO3- secretion evoked by VIP and blocked the vasodepressor response caused by VIP. By contrast, VIPi did not antagonize either the secretory or vasodepressor actions of PACAP. Unilateral electrical stimulation of the cervical vagus nerve evoked significant increases in the weight of juice, total protein and total HCO3- secreted. When preceded by injection of VIPi, vagally evoked secretions were unchanged in terms of weight of juice and total protein but had a significantly reduced HCO3- content. These results are consistent with the release of VIP, though not PACAP, as a vagal neurotransmitter in the exocrine pancreas.

Animals↗

PubMed1997

Anger attacks and treatment nonadherence in a perinatal psychiatry clinic.

Anger attacks are common in depressive disorders. High levels of anger have been associated with treatment nonadherence in medical and psychiatric patients. In this study we examined the relationship between anger attacks and treatment nonadherence in a perinatal psychiatry clinic that treats pregnant and postpartum women. Treatment adherence was examined by chart review. Patients with anger attacks at initial assessment were more likely to drop out of treatment than were patients without anger attacks at initial assessment (11/34 vs. 2/21; one-tailed Fisher's exact test p < .05). Treatment nonadherence among pregnant and postpartum women with anger attacks may be an important problem because of its impact on treatment outcome and because anger in depressed mothers is frequently directed at their children.

Adult↗