Are spacers made from sealed cold-drink bottles as effective as conventional spacers?
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Administration, Inhalation↗
Biomedical subjects
G Brown
Publications and source records attributed to G Brown.
A randomized controlled trial of strapping to prevent post-stroke shoulder pain.
OBJECTIVE: To determine whether strapping the shoulder in hemiplegic stroke patients: (1) prevents the development, or reduces the severity, of shoulder pain, (2) preserves range of movement in the shoulder, and (3) improves the functional outcomes for the arm and patient overall. DESIGN: A prospective, randomized, single-blind controlled trial of shoulder strapping versus no strapping. SETTING: Care of the elderly wards in a teaching hospital, Christchurch, New Zealand. SUBJECTS: All patients admitted with an acute hemiplegic stroke, who had persisting weakness of shoulder abduction. INTERVENTION: The treatment group had their affected shoulder strapped for six weeks from randomization in addition to standard physiotherapy. MAIN OUTCOME MEASURES: All subjects were assessed at entry (week 0), at end of the treatment phase (week 6) and two months later (week 14). A visual analogue scale (VAS) was used to assess shoulder pain severity whereas shoulder range of movement to the point of pain (SROMP) assessed passive range of movement and pain. Functional Independence Measure (FIM), Motor Assessment Scale (MAS) and Rankin Disability Index measured functional outcomes. RESULTS: Ninety-eight subjects participated (49 strapped, 49 controls). Intention to treat analysis showed no significant difference in pain, range of movement or functional outcomes after the intervention phase or at the final assessment. However there were trends for less pain at six weeks (VAS, p = 0.11) and better final upper limb function (MAS, p = 0.16) in strapped patients. Skin reactions were uncommon (6.1%). The presence of neglect or sensory loss, but not subluxation, at baseline was independently associated with poor outcome. Range of movement was lost early (mean difference SROMP between hemiplegic and contralateral shoulders at baseline = 15.2 degrees (95% CI 10.9-19.5)) and continued throughout the study. Shoulder strapping did not alter the rate at which range of movement was lost. CONCLUSIONS: No significant benefit with shoulder strapping was demonstrated and reasons for this are discussed. Range of movement in the hemiplegic shoulder is lost very early and any preventive treatments need to begin within the first 1-2 days after a stroke.
Aged↗
Cell adhesion and motility depend on nanoscale RGD clustering.
Integrin adhesion receptors play a crucial role in regulating interactions between cells and extracellular matrix (ECM). Integrin activation initiates multiple intracellular signaling pathways and results in regulation of cell functions such as motility, proliferation and differentiation. Two key observations regarding the biophysical nature of integrin-mediated cell-matrix interactions motivated the present study: (1) cell motility can be regulated by modulating the magnitude of cell-substratum adhesion, by varying cell integrin expression level, integrin-ECM binding affinity or substratum ECM surface density; and (2) integrin clustering enables assembly of multiple cytoplasmic regulatory and structural proteins at sites of aggregated integrin cytoplasmic domains, activating certain intracellular signalling pathways. Here, using a minimal integrin adhesion ligand, YGRGD, we test the hypothesis that ligand clustering can affect cell migration in a manner related to its modulation of cell-substratum adhesion. We employ a synthetic polymer-linking method, which allows us to independently and systematically vary both the average surface density and the local (approx. 50 nm scale) spatial distribution of the YGRGD peptide, against a background otherwise inert with respect to cell adhesion. In this system, the ligand was presented in three alternative spatial distributions: singly, in clusters with an average of five ligands per cluster, or in clusters with an average of nine ligands per cluster; for each of these spatial distributions, a range of average ligand densities (1,000-200,000 ligands/micrometer(2)) were examined. Cluster spacing was adjusted in order to present equivalent average ligand densities independently of cluster size. The murine NR6 fibroblast cell line was used as a model because its migration behavior on ECM in the presence and absence of growth factors has been well-characterized and it expresses integrins known to interact with the YGRGD peptide. Using time-lapse videomicroscopy and analysis of individual cell movement paths, we find that NR6 cells can migrate on substrata where adhesion is mediated solely by the YGRGD peptide. As previously observed for migration of NR6 cells on fibronectin, migration speed on YGRGD is a function of the average surface ligand density. Strikingly, clustering of ligand significantly reduced the average ligand density required to support cell migration. In fact, non-clustered integrin ligands support cell attachment but neither full spreading nor haptokinetic or chemokinetic motility. In addition, by quantifying the strength of cell-substratum adhesion, we find that the variation of cell speed with spatial presentation of YGRGD is mediated via its effect on cell adhesion. These effects on motility and adhesion are also observed in the presence of epidermal growth factor (EGF), a known motility-regulating growth factor. Variation in YGRGD presentation also affects the organization of actin filaments within the cell, with a greater number of cells exhibiting stress fibers at higher cluster sizes of YGRGD. Our observations demonstrate that cell motility may be regulated by varying ligand spatial presentation at the nanoscale level, and suggest that integrin clustering is required to support cell locomotion.
3T3 Cells↗
Small, efficient hammerhead ribozymes.
The hammerhead ribozyme is able to cleave RNA in a sequence-specific manner. These ribozymes are usually designed with four basepairs in helix II, and with equal numbers of nucleotides in the 5' and 3' hybridizing arms that bind the RNA substrate on either side of the cleavage site. Here guidelines are given for redesigning the ribozyme so that it is small, but retains efficient cleavage activity. First, the ribozyme may be reduced in size by shortening the 5' arm of the ribozyme to five or six nucleotides; for these ribozymes, cleavage of short substrates is maximal. Second, the internal double-helix of the ribozyme (helix II) may be shortened to one or no basepairs, forming a miniribozyme or minizyme, respectively. The sequence of the shortened helix + loop II greatly affects cleavage rates. With eight or more nucleotides in both the 5' and the 3' arms of a miniribozyme containing an optimized sequence for helix + loop II, cleavage rates of short substrates are greater than for analogous ribozymes possessing a longer helix II. Cleavage of gene-length RNA substrates may be best achieved by miniribozymes.
Base Sequence↗
Condom promotion in microbicide trials.
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Anti-Infective Agents↗
Monocytically differentiating HL60 cells proliferate rapidly before they mature.
1alpha,25-Dihydroxyvitamin D(3) (D(3)) provokes growth arrest and monocytic differentiation in myeloid cells. Although it is usually assumed that the cellular events leading to growth arrest start within one cell cycle of D(3) addition, there is also evidence that D(3) provokes the expression of proliferation-related genes and accelerates cell division. Herein we clarify the relationship between proliferation and maturation in differentiating HL60 cells. Cells were cultured singly, D(3) was added at various stages of the cell cycle, the progeny were counted, and the proportions of mature monocytes were determined. Initially, the D(3)-treated cells proliferated at an accelerated rate, and they matured only later. If cells encountered D(3) early in G1 they divided two to four times before maturing, and if they encountered D(3) later in the cell cycle they underwent an extra division. Indomethacin slows HL60 cell multiplication by prolonging G1, and when these slower-growing cells were exposed to D(3), they matured after the usual period but underwent one division less than indomethacin-free cells. Contrary to common assumptions, we conclude that promyeloid cells do not initiate growth arrest or monocytic maturation immediately after exposure to D(3). Instead, an encounter with D(3) early in G1 sets in train a complex differentiation program. This consists of 2-3 days of rapid proliferation-probably employing cell cycles with a shortened G1 phase-that is followed by growth arrest and maturation. As a result, a single D(3)-treated promyeloid cell gives rise to 10 or more mature monocytes. These observations not only explain why "differentiating" cells express proliferation-related characteristics soon after D(3) addition, but they also show that the process of D(3)-induced monocytic differentiation is much more complex than has previously been realized.
Anti-Inflammatory Agents↗
Inhibition of mitochondrial function in HL60 cells is associated with an increased apoptosis and expression of CD14.
The myelomonocytic cell line HL60 can be induced by a variety of chemical agents to differentiation to either neutrophils or monocytes. Examination of gene expression, by differential display, in cells induced to monocytes with 1alpha,25-dihydroxyvitamin D(3) or neutrophils with all-trans retinoic acid (ATRA) identified a number of clones with altered patterns of expression over the period of differentiation. One of these clones was the mitochondrial gene NADH dehydrogenase subunit 4 (ND4) which showed a differential pattern of expression between the neutrophil and monocyte lineages. The potential of mitochondrial inhibitors to induce differentiation was investigated by treating the HL60 cells with either the NADH dehydrogenase inhibitor, Rotenone, the complex III inhibitor, Antimycin A, or the highly specific mitochondrial ATP-synthase inhibitor, Oligomycin. Although functional assays of differentiation did not produce any positive results, all the inhibitors resulted in a dramatic increase in CD14 expression at day 1, with CD38 markers not observed until day 3. The increased expression of CD14 was accompanied by a decrease in viability and all CD14 positive cells were also positive for Annexin V, a marker of apoptosis. These results suggest that inhibition of the components of the mitochondrial pathways may lead to the marking of some cells, via CD14, for cell death, whilst allowing commitment to differentiation to occur in the surviving population.
ADP-ribosyl Cyclase↗
Home-made spacers for bronchodilator therapy in children with acute asthma: a randomised trial.
BACKGROUND: A metered-dose inhaler (MDI) with spacer is the best way to deliver bronchodilator therapy for treatment of acute asthma. In developing countries, commercially produced spacers are generally unavailable or too costly. We tested the efficacy of home-made spacers (500 mL plastic bottle, polystyrene cup) compared with a conventional spacer for delivery of a beta2 agonist via MDI for children with acute asthma. METHODS: We studied children aged 5 to 13 years with acute asthma, stratified into those with mild airways obstruction (peak expiratory flow [PEF] 60-79% of predicted value) or moderate to severe airways obstruction (PEF 20-59% of predicted value). A beta2 agonist (fenoterol hydrobromide) was given via MDI and one of four randomly assigned spacers (conventional spacer, sealed 500 mL plastic bottle, unsealed 500 mL bottle, 200 mL polystyrene cup). Clinical score, pulmonary function tests, and oximetry were recorded at baseline and 15 min after treatment. If a second bronchodilator treatment was needed, nebulised fenoterol was given and the assessment repeated 15 min later. Primary outcome measures were changes in clinical score and pulmonary function, and need for and response to nebulisation. FINDINGS: 88 children were eligible for study. In 44 children with moderate to severe airways obstruction, a cup gave significantly less bronchodilation (median increase in: forced expiratory volume in 1 s [FEV1] 0%; PEF 12%) compared with the conventional spacer (37%; 59%), sealed bottle (33%; 36%), or unsealed bottle (18%; 21%, p<0.05 for difference between groups). Nebulisation was required by ten of 11 who had used a cup, nine of 11 who had used an unsealed bottle, eight of 11 who had used a sealed bottle, and only four of 11 who had used a conventional spacer. After nebulisation, improvement in FEV1 (15.5%) and PEF (26%) was more marked in children who had used a cup than in those who had used a conventional spacer (5.5% FEV1; 4% PEF), sealed bottle (3%; 0%), or unsealed bottle (7%; 9%). For 44 children with mild airways obstruction, response to bronchodilator was similar for all spacers and need for nebulisation was not associated with use of a particular spacer. INTERPRETATION: A conventional spacer and sealed 500 mL plastic bottle produced similar bronchodilation, an unsealed bottle gave intermediate improvement in lung function, and a polystyrene cup was least effective as a spacer for children with moderate to severe airways obstruction. Use of bottle spacers should be incorporated into guidelines for asthma management in developing countries.
Administration, Inhalation↗
Underascertainment of child abuse mortality in the United States.
CONTEXT: Mortality figures in the United States are believed to underestimate the incidence of fatal child abuse. OBJECTIVES: To describe the true incidence of fatal child abuse, determine the proportion of child abuse deaths missed by the vital records system, and provide estimates of the extent of abuse homicides in young children. DESIGN AND SETTING: Retrospective descriptive study of child abuse homicides that occurred over a 10-year period in North Carolina from 1985-1994. CASES: The Medical Examiner Information System was searched for all cases of children younger than 11 years classified with International Classification of Diseases, Ninth Revision codes E960 to E969 as the underlying cause of death and homicide as the manner of death. A total of 273 cases were identified in the search and 259 cases were reviewed after exclusion of fetal deaths and deaths of children who were not residents of North Carolina. MAIN OUTCOME MEASURE: Child abuse homicide. RESULTS: Of the 259 homicides, 220 (84.9%) were due to child abuse, 22 (8.5%) were not related to abuse, and the status of 17 (6.6%) could not be determined. The rate of child abuse homicide increased from 1.5 per 100000 person-years in 1985 to 2.8 in 1994. Of all 259 child homicides, the state vital records system underrecorded the coding of those due to battering or abuse by 58.7%. Black children were killed at 3 times the rate of white children (4.3 per 100000 vs 1.3 per 100000). Males made up 65.5% (133/203) of the known probable assailants. Biological parents accounted for 63% of the perpetrators of fatal child abuse. From 1985 through 1996, 9467 homicides among US children younger than 11 years were estimated to be due to abuse rather than the 2973 reported. The ICD-9 cause of death coding underascertained abuse homicides by an estimated 61.6%. CONCLUSIONS: Using medical examiner data, we found that significant underascertainment of child abuse homicides in vital records systems persists despite greater societal attention to abuse fatalities. Improved recording of such incidences should be a priority so that prevention strategies can be appropriately targeted and outcomes monitored, especially in light of the increasing rates.
Black or African American↗
L-selectin interactions with novel mono- and multisulfated Lewisx sequences in comparison with the potent ligand 3'-sulfated Lewisa.
The cell adhesion molecule L-selectin binds to 3'-sialyl-Lewis (Le)x and -Lea and to 3'-sulfo-Lex and -Lea sequences. The binding to 3'-sialyl-Lex is strongly affected by the presence of 6-O-sulfate as found on oligosaccharides of the counter receptor, GlyCAM-1; 6-O-sulfate on the N-acetylglucosamine (6-sulfation) enhances, whereas 6-O-sulfate on the galactose (6'-sulfation) virtually abolishes binding. To extend knowledge on the specificity of L-selectin, we have investigated interactions with novel sulfo-oligosaccharides based on the Lex pentasaccharide sequence. We observe that, also with 3'-sulfo-Lex, the 6-sulfation enhances and 6'-sulfation suppresses L-selectin binding. The 6'-sulfation without 3'-sialyl or 3'-sulfate gives no binding signal with L-selectin. Where the 6-sulfo,3'-sialyl-Lex is on an extended di-N-acetyllactosamine backbone, additional 6-O-sulfates on the inner galactose and inner N-acetylglucosamine do not influence the binding. Although binding to the 6,3'-sulfo-Lex and 6-sulfo, 3'-sialyl-Lex sequences is comparable, the former is a more effective inhibitor of L-selectin binding. This difference is most apparent when L-selectin is in paucivalent form (predominantly di- and tetramer) rather than multivalent. Indeed, as inhibitors of the paucivalent L-selectin, the 3'-sulfo-Lex series are more potent than the corresponding 3'-sialyl-Lex series. Thus, for synthetic strategies to design therapeutic oligosaccharide analogs as antagonists of L-selectin binding, those based on the simpler 3'-sulfo-Lex (and also the 3'-sulfo-Lea) would seem most appropriate.
Carbohydrate Sequence↗
Bistratene A induces a microtubule-dependent block in cytokinesis and altered stathmin expression in HL60 cells.
Bistratene A is a cyclic polyether which affects cell cycle progression and can induce phosphorylation of cellular proteins. Treatment of HL60 cells with 100 ng/ml bistratene A was found to inhibit cytokinesis but had no effect on DNA synthesis and nuclear division. Consequently, bistratene A-treated cells became polyploid and multinucleate. In association with the development of this phenotype, the cytoplasmic protein stathmin was biphasically phosphorylated and levels of expression were doubled. Immunostaining of binucleate cells (bistratene A for 24 h) revealed increased alpha-tubulin localization where the cleavage furrow might be expected to form, i.e., along the equatorial plane. Treatment of these binucleate cells with the microtubule depolymerizing agent nocadazole promoted cleavage furrow formation and partially ameliorated the bistratene A-induced block in cell division. These findings implicate the polymerization status of microtubules and stathmin function in the regulation of cytokinesis.
Acetamides↗
Whistle blowing. In on the act?
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Hospitals, Public↗
Adsorption of Au ferrihydrites using Au-LIII edge XAFS spectroscopy.
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Journal Article↗
Rural background and clinical rural rotations during medical training: effect on practice location.
BACKGROUND: Providing health care services in rural communities in Canada remains a challenge. What affects a family medicine resident's decision concerning practice location? Does the resident's background or exposure to rural practice during clinical rotations affect that decision? METHODS: Cross-sectional mail survey of 159 physicians who graduated from the Family Medicine Program at Queen's University, Kingston, Ont., between 1977 and 1991. The outcome variables of interest were the size of community in which the graduate chose to practise on completion of training (rural [population less than 10,000] v. nonrural [population 10,000 or more]) and the size of community of practice when the survey was conducted (1993). The predictor or independent variables were age, sex, number of years in practice, exposure to rural practice during undergraduate and residency training, and size of hometown. RESULTS: Physicians who were raised in rural communities were 2.3 times more likely than those from nonrural communities to choose to practise in a rural community immediately after graduation (95% confidence interval 1.43-3.69, p = 0.001). They were also 2.5 times more likely to still be in rural practice at the time of the survey (95% confidence interval 1.53-4.01, p = 0.001). There was no association between exposure to rural practice during undergraduate or residency training and choosing to practise in a rural community. INTERPRETATION: Physicians who have roots in rural Canada are more likely to practise in rural Canada than those without such a background.
Adult↗
Metabolism of 1alpha,25(OH)2D3 and its 20-epi analog integrates clonal expansion, maturation and apoptosis during HL-60 cell differentiation.
Induction of growth arrest and monocyte differentiation of HL-60 leukemia cells by 1alpha,25 dihydroxyvitamin D3 (1alpha,25(OH)2D3) is well established. By contrast, we have observed, that 1alpha,25(OH)2D3 and its metabolites play separate roles in clonal expansion and survival of differentiating HL-60 cells. Cells that had differentiated by 48 h (CD14 positive) grew slower than control cells, whereas CD14 negative cells were growing faster at this time point. Inhibiting 1alpha,25(OH)2D3 or 1alpha,25(OH)2-20-epi-D3 metabolism, by the 25(OH)D3-24-hydroxylase inhibitor ketoconazole, abolished hyperproliferation of CD14 negative cells. Instead, both the onset of differentiation and subsequent apoptosis were enhanced. These events were associated with immediate up-regulation of the cyclin-dependent kinase inhibitor p21(waf1) and a lack of sustained expression, respectively. Stimulation and inhibition of growth by vitamin D3-related compounds was observed to be concentration and metabolite specific. Low amounts of 1alpha,25(OH)2-20-epi-D3 and 1alpha,24,25(OH)3-20-epi-D3 stimulated HL-60 cell growth. At higher concentrations, 1alpha,25(OH)2-20-epi-D3 was a more potent inducer than 1alpha,24,25(OH)3-20-epi-D3 of HL-60 differentiation; 1alpha,25(OH)2-20-epi-24-oxo-D3 was exclusively pro-differentiative at all concentrations. 1alpha,25(OH)2-20-epi-D3 and 1alpha,24,25(OH)3-20-epi-D3 stimulated proliferation of KG-1a leukemia cells, but neither of these compounds nor 1alpha,25(OH)3-20-epi-24-oxo-D3 exerted pro-differentiative effects on these cells. These findings shed new light on the pro- and anti-proliferative effects of 1alpha,25(OH)2D3 and lead to the postulate that metabolism of 1alpha,25(OH)2D3 and its 20-epi analog regulates different subsets of genes so as to co-ordinate population expansion and the differentiation process. Furthermore, 1alpha,25(OH)2D3 metabolism and/or sensitivity to the effects of metabolites may be altered in transformed cells to derive a clonal advantage.
Apoptosis↗
Long stay care and the NHS. Scottish health resource utilisation groups measure is helpful.
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Aged↗
Estrone potentiates myeloid cell differentiation: a role for 17 beta-hydroxysteroid dehydrogenase in modulating hemopoiesis.
Hormones such as 1 alpha, 25-dihydroxy vitamin D3 (D3), all-trans retinoic acid, and 9-cis retinoic acid stimulate differentiation of myeloid progenitor cells via their interaction with specific hormone receptors. However, the sensitivity of cells to these agents is not merely governed by the expression of their receptors and the availability of ligand to bind them. Recent studies from our group suggested that the actions of D3 and retinoids on myelopoiesis also are influenced by endogenous mechanisms involving other steroid hormones. In this study we examined the influence of local estrogen metabolism on the differentiation of HL60 cells and normal primitive myeloid progenitor cells. Quantitative thin-layer chromatography (TLC) analyses showed that HL60 and normal cells are able to generate estrone (E1) from estradiol (E2). Neither cell population generated significant amounts of E2 from E1. Reverse transcriptase polymerase chain reaction and Northern analyses confirmed that normal and leukemic myeloid progenitor cells expressed mRNA for the type I and IV isoforms of 17 beta-hydroxysteroid dehydrogenase. Conversion of E2 to E1 was upregulated within 24 hours when HL60 cells were treated with either all-trans retinoic acid or D3 at doses that induce their differentiation toward neutrophils or monocytes, respectively. Similarly, D3-induced monocyte differentiation of normal myeloid progenitor cells was associated with increased capacity to generate E1 from E2. When HL60 cells or normal myeloid progenitor cells were exposed to exogenous E1 they became more sensitive to the differentiation-inducing effects of D3. Data presented provide further evidence for the local modulation of myelopoiesis by intracrine mechanisms. In particular, our findings suggest that local metabolism of steroids by normal as well as leukemic myeloid cells influences their responsiveness to D3 and retinoids.
17-Hydroxysteroid Dehydrogenases↗
Mechanisms of ischaemic damage to central white matter axons: a quantitative histological analysis using rat optic nerve.
The mechanism of ischaemic injury to white matter axons was studied by transiently depriving rat optic nerves in vitro of oxygen and glucose. Light and electron microscopic analysis showed that increasing periods of oxygen/glucose deprivation (up to 1 h) caused, after a 90-min recovery period, the appearance of increasing numbers of swollen axons whose ultrastructure indicated that they were irreversibly damaged. This conclusion was supported by experiments showing that the damage persisted after a longer recovery period (3 h). To quantify the axonal pathology, an automated morphometric method, based on measurement of the density of swollen axons, was developed. Omission of Ca2+ from the incubation solution during 1 h of oxygen/glucose deprivation (and for 15 min either side) completely prevented the axonopathy (assessed following 90 min recovery). Omission of Na+ was also effective, though less so (70% protection). The classical Na+ channel blocker, tetrodotoxin (1 microM), provided 92% protection. In view of this evidence implicating Na+ channels in the pathogenesis of the axonal damage, the effects of three different Na+ channel inhibitors, with known neuroprotective properties towards gray matter in in vivo models of cerebral ischaemia, were tested. The compounds used were lamotrigine and the structurally-related molecules, BW619C89 and BW1003C87. All three compounds protected the axons to varying degrees, the maximal efficacies (observed at 30 to 100 microM) being in the order: BW619C89 (>95% protection) > BW1003C87 (70%) > lamotrigine (50%). At a concentration affording near complete protection (100 microM), BW619C89 had no significant effect on the optic nerve compound action potential. Experiments in which BW619C89 was added at different times indicated that its effects were exerted during two distinct phases, one (accounting for about 50% protection) was during the early stage of oxygen/glucose deprivation itself and the other (also about 50%) during the first 15 min of recovery in normal incubation solution. The results are consistent with a pathophysiological mechanism in which Na+ entry through tetrodotoxin-sensitive Na+ channels contributes to Na+ loading of the axoplasm which then results in a lethal Ca2+ overload through reversed Na(+)-Ca2+ exchange. The identification of BW619C89 as a compound able to prevent oxygen/glucose deprivation-induced injury to white matter axons without affecting normal nerve function opens the way to testing the importance of this pathway in white matter injury in vivo.
Animals↗