Search PubMed⌕ Search

Biomedical subjects

E Henderson

Publications and source records attributed to E Henderson.

At least 91 records · Page 5Linked to original sources
PubMed1993

Prolonged and multipatient use of prefilled disposable oxygen humidifier bottles: safety and cost.

OBJECTIVES: Multipatient use and prolonged use of prefilled disposable oxygen humidifier bottles (Aquapak 301, Respiratory Care, Inc., Arlington Heights, IL) were evaluated by performing microbiologic monitoring and a cost analysis on bottles used for varying numbers of patients and lengths of time. METHODS: Humidifiers were hung for a maximum of one month. Monitoring was conducted in 6 different nursing areas. Quantitative cultures were done for aerobes and Legionella. Reusable humidifier bottles also were monitored. RESULTS: Cultures were obtained from 1,311 disposable and 60 reusable humidifiers. No significant bacterial contamination was detected in the prefilled disposable oxygen humidifier units. Ten percent of the reusable bottles were contaminated by organisms associated with skin flora. CONCLUSIONS: Multipatient use and increased duration of use of disposable humidifiers result in cost savings without increasing patient risk. Restricted multipatient use of prefilled disposable oxygen humidifier bottles for a period of one month is a safe and cost-efficient practice.

Alberta↗
PubMed1993

A multicentre, double-blind, placebo-controlled trial of quinapril in mild, chronic heart failure.

Angiotensin converting enzyme (ACE) inhibitors are of proven value in patients with severe chronic heart failure (CHF). Studies of the effects of ACE inhibitors on exercise capacity and quality of life in mild CHF have produced conflicting results. We have studied the effects of quinapril, a new ACE inhibitor with a relatively short plasma half-life, in mild CHF. Once daily (o.d.) dosing was compared with twice daily (b.i.d.) dosing in a three-way cross-over, double-blind, placebo-controlled trial. Thirty-two patients (two female), mean age 59 (range 32-76) years were enrolled in three cardiology centres in the U.K. in 29 patients, and non-ischaemic in three. The mean (range) radionuclide ejection fraction was 20.4% (8%-47%). Following full familiarization with the protocol, the treadmill exercise time (modified Bruce protocol) was determined for each patient during a placebo run-in phase, and at the end of each of three 8-week double-blind treatment phases with quinapril o.d., quinapril b.i.d. (maximal total daily dose 20 mg) and placebo. Three patients were withdrawn due to adverse events while receiving quinapril (unstable angina, exacerbation of CHF and arrhythmia); there were no deaths and no patient was withdrawn due to hypotension. Mean exercise time (the primary end-point) was 65 s and 53 s longer in patients receiving quinapril o.d. and b.i.d. respectively compared to placebo (both P < 0.01, ANOVA). There was no significant period effect during the trial and no significant difference between the two quinapril dosing regimens. Quinapril had no significant effect on secondary end-points including ejection fraction, functional class and quality of life.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Three-dimensional imaging of living neurons and glia with the atomic force microscope.

The atomic force microscope (AFM) was used to directly image hippocampal neurons and glia. Using chemically fixed and living cells it was possible to reconstruct three-dimensional cell structure and detect sub-cellular features such as the nucleus, mitochondria and filaments. By repeatedly scanning a single living cell we observed the movement of filaments beneath the cell membrane. Furthermore, by controlling the force applied to the scanning tip, nanosurgery was performed to selectively remove cells from the culture substratum. Thus, the atomic force microscope offers the opportunity to gain three-dimensional information about living cells and to observe the behavior of cellular components by imaging through the intact cell membrane.

Animals↗
PubMed1993

Humidity effects on atomic force microscopy of gold-labeled DNA on mica.

Recent work in atomic force microscopy (AFM) of deoxyribonucleic acid (DNA) has relied on immobilizing DNA molecules by drying a small volume of buffered DNA solution onto cleaved mica. When imaging in air, relative humidity has been known to affect both the resolution and measured height of the DNA strands. We present data of measured height versus humidity for DNA and attached gold labels, and we propose a model for this data based on swelling of coadsorbed buffer salts upon exposure to moisture. In this model, small particles (e.g., DNA) stay near the top of the swelling salt layer, whereas larger particles (e.g., gold spheres) tend to be anchored down to the substrate until a moderate humidity is reached. At high humidity (around 65%), the salt layer becomes fluid-like and susceptible to tip-induced motion; the salts are either removed from the scan area or aggregate into island structures, depending on initial salt concentration on the surface.

Aluminum Silicates↗
PubMed1992

Hodgkin disease survivors at increased risk for problems in psychosocial adaptation. The Cancer and Leukemia Group B.

BACKGROUND: The long-term psychosocial adaptations of 273 survivors of advanced Hodgkin disease were assessed to determine the nature and extent of problems experienced and to identify those at high risk for maladaptation. METHODS: Hodgkin disease survivors were identified who initially had been treated in clinical trials within the Cancer and Leukemia Group B from 1966 to 1986, were currently disease free, and had completed treatment for a minimum of 1 year. All survivors had advanced Hodgkin disease (with disease diagnosed at a mean age of 28 years). Survivors were at a mean age of 37 years at the time of interview (6.3 years after treatment completion), and 60% were male. Survivors were interviewed over the telephone 7-10 days after questionnaires were mailed to them concerning their psychological, social, vocational, and sexual functioning. RESULTS: Psychological distress was found to be elevated by one standard deviation (SD) above that of healthy subjects on the Brief Symptom Inventory, and 22% met the criterion suggested for a psychiatric diagnosis. In addition, the following problems were reported by survivors to be a consequence of having had Hodgkin disease: denial of life (31%) and health (22%) insurance, sexual problems (37%), conditioned nausea in response to reminders of chemotherapy (39%), and a negative socioeconomic effect (36%). Survivors found to be at high risk for maladaptation were: men earning less than $15,000 per year or who were currently unemployed; unmarried individuals; those with serious illnesses since treatment completion; and those who were less educated. CONCLUSIONS: These findings suggest that including a routine assessment of these factors would help to target survivors in need of additional evaluation and treatment.

Adaptation, Psychological↗
PubMed1992

Actin filament dynamics in living glial cells imaged by atomic force microscopy.

Observation of filamentous actin (F-actin) in living cells is currently limited to the resolution of the light microscope. Higher resolution procedures require sample fixation and preclude dynamic studies. The atomic force microscope (AFM) can image and manipulate samples at very high, sometimes atomic resolution by scanning a fine tip over the surface of interest and detecting physical interactions between the tip and sample. This study demonstrates that F-actin can be readily resolved in living cells with the AFM and that the dynamic properties of F-actin are easily observed.

Actin Cytoskeleton↗
PubMed1992

Pregnancy outcome in survivors of advanced Hodgkin disease.

BACKGROUND: Pregnancy outcome was reported by 139 survivors of advanced Hodgkin disease treated on nine protocols of Cancer and Leukemia Group B from 1966 to 1986. METHODS: These patients provided data on 302 singleton pregnancies of a duration of at least 20 weeks that occurred before, during, or after treatment for Hodgkin disease (252, 26, and 24 pregnancies, respectively). RESULTS: There were 4 perinatal deaths, as compared with 5.7 expected. Cancer subsequently developed in 2 offspring (expected, 1.2). However, 22 newborn infants had low a birth weight, exceeding the expected number of 13.7 (relative risk 1.6; 95% confidence interval, 1.0-2.4). The excess number of low weight births occurred primarily during the period of Hodgkin disease diagnosis and treatment but is based on small numbers. CONCLUSION: No increase in adverse outcome occurred in pregnancies that antedated the development of Hodgkin disease.

Adult↗
PubMed1992

Imaging and nanodissection of individual supercoiled plasmids by atomic force microscopy.

The atomic force microscope (AFM) was used to image supercoiled plasmid DNA deposited on a mica surface in either a hydrated or desiccated state. Hydrated plasmid was precisely cut by the scanning tip at a location determined by the instrument operator. Small pieces of DNA (100-150 nm in length) were excised and deposited adjacent to the dissected plasmid, demonstrating that it is possible to remove and manipulate genomic DNA fragments, unresolvable by light microscopy, from defined chromosomal locations by AFM.

DNA, Superhelical↗
PubMed1992

Formation of novel hairpin structures by telomeric C-strand oligonucleotides.

Telomeres are specialized structures at the ends of chromosomes that are required for long term chromosome stability and replication of the chromosomal terminus. Telomeric DNA consists of simple repetitive sequences with one strand G-rich relative to the other, C-rich, strand. Evolutionary conservation of this feature of telomeric repeat sequences suggests that they have specific structural characteristics involved in telomere function. Absorbance thermal denaturation, chemical modification and non-denaturing gel electrophoretic analyses showed that telomeric C-strand oligonucleotides form stable non-Watson-Crick hairpin structures containing C.C+ base pairs. Formation of such hairpins may facilitate previously reported G-strand exclusive interactions.

Animals↗
PubMed1992

Dehydroepiandrosterone (DHEA) and synthetic DHEA analogs are modest inhibitors of HIV-1 IIIB replication.

Down-regulation of Epstein-Barr virus (EBV) induced transformation of human lymphocytes in vitro by dehydroepiandrosterone (DHEA), a naturally occurring human steroid secreted by the adrenal gland has been demonstrated. This article reports on the effects of DHEA and its novel synthetic analogs 16 alpha-fluoro-5-androsten-17-one (8354) and 3 beta-hydroxy-16 alpha-fluoro-5 alpha-androstan-17-one (OH8356) on human immunodeficiency virus (HIV-1) replication. Treatment with DHEA, 8354, or OH8356 resulted in a modest down-regulation of HIV-1 replication in phytohemagglutinin-stimulated peripheral blood lymphocytes as measured by syncytia formation, release of p24 antigen, and accumulation of reverse transcriptase activity. DHEA and 8354 also reduced syncytia formation in HIV-1-infected SupT1 lymphoblasts. DHEA and synthetic analogs of DHEA, which have been shown previously to have antiproliferative effects, now are shown to reduce HIV-1 replication. DHEA or synthetic analogs of DHEA could provide an alternative and/or adjuvant for HIV-1 infection.

Androstenes↗
PubMed1992

The use of an exponential protocol for bicycle and treadmill exercise testing in patients with chronic cardiac failure.

We have studied a standardized exercise protocol suitable for use with a treadmill or bicycle (STEEP protocol) and compared it with a modified Bruce treadmill protocol in a group of patients with chronic cardiac failure. The STEEP protocol has been previously validated in normal subjects. Exercise time (6.79 +/- 2.42 vs 5.34 +/- 1.95 min, P < 0.05) and peak VO2 (16.66 +/- 4.09 vs 15.01 +/- 3.72 ml.min-1.kg-1, P < 0.05) were greater with the STEEP treadmill compared with the bicycle protocol, but VO2 was very similar at equal exercise stages in both modalities. Heart rate and respiratory exchange ratio tended to be greater during bicycle exercise at equal stages. Exercise time was greater with the modified Bruce protocol (9.00 +/- 3.02 min, P < 0.05) than with either STEEP protocol, but peak VO2 (17.13 +/- 4.52 ml.min-1.kg-1) was similar to that obtained with the STEEP treadmill test. We conclude that the STEEP protocol may be used to test patients with chronic cardiac failure, and that exercise times relate well in both treadmill and bicycle. The protocol should prove useful in studies involving a wide range of exercise capacities or both bicycle and treadmill exercise.

Aged↗
PubMed1992

Urinary collagen crosslinks reflect the radiographic severity of knee osteoarthritis.

The collagen crosslinks deoxypyridinoline and pyridinoline are indices of mature collagen breakdown and reflect increased bone turnover. Urinary levels were found to be significantly raised in a group of 59 women with knee OA compared to 110 female controls from the general population. Levels of the crosslinks correlated significantly with X-ray grade of all subjects including women from the general population with mild, often asymptomatic, disease. These correlations were not diminished after adjustment for age and weight.

Aged↗
PubMed1992

T lymphocyte adhesion to fibronectin (FN): a possible mechanism for T cell accumulation in the rheumatoid joint.

The accumulation of T cells within the joint is responsible for the perpetuation of synovitis. This process is partly regulated by selective binding to endothelium. However, adhesion to extra-cellular matrix proteins, like FN, may also be important. FN binding is mediated by certain members of the VLA (beta 1 integrin) family of proteins. To investigate the role of Tc-FN interactions in synovitis the binding of synovial fluid (SF) and peripheral blood (PB) T cells to FN-coated wells, and the expression of cell surface VLA molecules on these cells by double label immunofluorescence, were studied. SF T cells bound better to FN than PB T cells. VLA alpha 4 and VLA beta 1 but not VLA alpha 5 were up-regulated on SF compared with PB T cells. Anti-VLA alpha 4, VLA beta 1 and VLA alpha 5 MoAbs inhibited the binding of SF T cells to FN. The increased binding of SF T cells to FN could have been related to activation and/or to their predominantly memory phenotype. Purified resting memory or naive T cells bound poorly to FN. In contrast, compared with SF T cells, concanavalin A-activated T cells showed a very similar level of binding to FN, comparable expression of VLA molecules and the same pattern of inhibition of binding to FN by MoAbs. Thus, VLA molecules may play an important role in the retention of T cells in the joint and since T cells can be activated via VLA-FN interactions, this mechanism may perpetuate chronic inflammation.

Arthritis, Rheumatoid↗
PubMed1992

Atomic force microscopy of conventional and unconventional nucleic acid structures.

Images of conventional (Watson-Crick base paired) and unconventional (G4 RNA) nucleic acid structures have been obtained by atomic force microscopy. The images are reproducibly generated from samples deposited on freshly cleaved mica. Periodic substructural features are evident in fibres observed in both cases. In the case of G4 RNA, tip-induced formation of large fibres is observed.

DNA↗
PubMed1992

Increased circulating atrial natriuretic factor concentrations in patients with chronic heart failure after inhibition of neutral endopeptidase: effects on diastolic function.

OBJECTIVE: +/- Candoxatrilat was used to raise atrial natriuretic factor (ANF) concentrations in patients with heart failure, and the effects on left ventricular systolic and diastolic function were studied to determine the contribution of peripheral and central mechanisms to the haemodynamic effects. DESIGN: This was a single blind, randomised comparison of +/- candoxatrilat and placebo in patients with mild heart failure. All patients received two intravenous doses of +/- candoxatrilat and two placebo doses on four consecutive days. SETTING: A teaching hospital department of cardiology. PATIENTS: Six men (mean age 52 years) with mild heart failure (New York Heart Association class II) due to ischaemic heart disease (four patients) or dilated cardiomyopathy (two patients) were included. Mean ejection fraction was 37.5% and mean peak oxygen consumption was 20.4 ml/min/kg. MAIN OUTCOME MEASURES: Plasma ANF concentrations, haemodynamic indices and left ventricular diastolic function measured by early to atrial filling rate (E:A ratio) with Doppler echocardiography were determined before and after +/- candoxatrilat and placebo. RESULTS: +/- Candoxatrilat caused a threefold rise of plasma ANF compared with placebo (p < 0.005), but there was no significant change in heart rate, blood pressure, or cardiac output. Mean right atrial pressure fell from 6.7 to 4.7 mmHg (NS) and pulmonary artery wedge pressure fell from 9.2 to 6.7 mmHg (p < 0.05). Doppler echocardiographic measurements of transmitral blood flow showed a significant fall in peak early left ventricular filling velocity from 39.5 to 34.2 cm/s (p < 0.05), along with a non-significant rise in peak atrial filling velocity from 39.7-41.6 cm/s after +/- candoxatrilat. The E:A ratio, a Doppler index of left ventricular diastolic function, fell from a mean of 1.04 to 0.87 (p < 0.05). CONCLUSIONS: +/- Candoxatrilat increased plasma ANF concentrations and reduced right atrial and pulmonary artery wedge pressures. No evidence of an improvement in left ventricular systolic or diastolic function was found, so the fall in preload was due to peripheral effects, either an increase in venous capacitance or a fall in circulating blood volume.

Atrial Natriuretic Factor↗