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Biomedical subjects

J Elliott

Publications and source records attributed to J Elliott.

At least 127 records · Page 7Linked to original sources
PubMed1997

Alpha-adrenoceptors in equine digital veins: evidence for the presence of both alpha1 and alpha2-receptors mediating vasoconstriction.

Rings of equine digital vein examined under conditions of isometric tension recording constricted to alpha-adrenoceptor agonists with an order of potency of 5-bromo-6-[2-imidazolin-2-yl-amino]-quinoxaline bitartrate (UK 14304) = noradrenaline > 6-Allyl-2-amino-5,6,7,8-tetrahydro-4H-thiazolo-(4,5-d) azepine (BHT-920) > phenylephrine > dopamine > methoxamine. The maximum force generated was greatest for the non-selective agonist noradrenaline and lowest for the alpha2-selective agonist BHT-920 with the other agonists between these two extremes. Selective inactivation of alpha1-adrenoceptors (achieved by treating yohimbine-protected tissues with phenoxybenzamine) reduced the maximum responses of all agonists, the EC50 values of UK 14304, BHT-920 and noradrenaline and increased the EC50 values of phenylephrine and methoxamine. Prazosin (30 nM) had no inhibitory effect on responses to low concentrations of BHT-920 and UK 14304 and caused competitive inhibition of responses to phenylephrine and noradrenaline giving pKb values of 8.49 +/- 0.18 and 8.23 +/- 0.14, respectively. Yohimbine (0.1 microM) caused significant competitive inhibition of responses to BHT-920 and noradrenaline with calculated pKb values of 8.43 +/- 0.11 for BHT-920 and 7.43 +/- 0.31 for noradrenaline and non-competitive inhibition of responses to UK 14304. 2-[2-methoxy-1,4-benzodioxan-2-yl]-2-imidazoline (RX 821002; 10 nM) caused competitive inhibition of responses to BHT-920 (pKb 9.04 +/- 0.27) and dopamine (pKb 8.2 +/- 0.2). These data indicate that equine digital veins possess both post-synaptic alpha1 and alpha2-adrenoceptors.

Adrenergic alpha-Agonists↗
PubMed1997

Energy consumption in children with myelomeningocele: a comparison between reciprocating gait orthosis and hip-knee-ankle-foot orthosis ambulators.

This study compared the differences in energy efficiency (energy cost) in children with myelomeningocele ambulating with either reciprocating gait orthoses (RGOs) or hip-knee-ankle-foot orthoses (HKAFOs). There were 15 children who ambulated with RGOs and 11 children braced and ambulating in HKAFOs. Velocity was measured in m/s, energy consumption was measured in mL/kg/min, and energy cost (energy consumption/velocity) was measured in mL/kg/m. Children in HKAFOs had a significantly higher energy consumption rate than children in RGOs. However, children who swing through in a HKAFO have a significantly faster velocity than children who ambulate with the RGO using a reciprocating pattern. The increased energy cost in the RGO group is influenced by their slower velocity, just as the decreased energy cost in the HKAFO group is influenced by their increased velocity. Therefore it appears that children in HKAFOs are more energy efficient than children in RGOs.

Adolescent↗
PubMed1997

Nitric oxide production by equine articular cells in vitro.

Recent research in several species has suggested nitric oxide (NO) as a mediator of articular cartilage damage and an inhibitor of cartilage matrix neosynthesis. This study investigated NO production by cultured equine articular chondrocytes in response to 2 arthritogenic molecules, namely lipopolysaccharide (LPS) and interleukin-1 beta (IL-1 beta), and compared NO production by cultured equine synoviocytes stimulated with LPS. Synoviocytes exhibited a low basal level of NO synthesis (measured as nitrite, a NO metabolite) that was neither significantly increased nor decreased by exposure to LPS. Basal NO synthesis by synoviocytes was not significantly reduced by competitive inhibitors of nitric oxide synthase (NOS). In contrast, chondrocytes treated with LPS or IL-1 beta synthesised nitrite in a dose-related manner. Inhibitors of NOS suppressed nitrite production to below the basal levels of release of unstimulated cells. Dexamethasone, an inhibitor of induction of the inducible isoform of NOS (iNOS), reduced nitrite synthesis by LPS-stimulated chondrocytes. Western blot analysis revealed expression, in response to LPS, of protein in the same molecular weight range as iNOS identified in other species. This work demonstrates that equine chondrocytes have the capacity to synthesise NO, although its exact roles in cartilage metabolism have yet to be determined.

Animals↗
PubMed1997

The Ilizarov method in nonunion, malunion and infection of fractures.

We have reviewed a series of 56 consecutive patients treated by the Ilizarov circular fixator for various combinations of nonunion, malunion and infection of fractures. We used segmental excision, distraction osteogenesis and gradual correction of the deformity as appropriate. Treatment was effective in eliminating 40 out of 46 nonunions and all 22 infections. There were two cases of refracture some months after removal of the frame, both of which healed securely in a second frame. Correction of malunion was good in the coronal plane but there was a tendency to anterior angulation, often occurring in the regenerate bone rather than at the original fracture site, after removal of the frame. This was associated with very slow maturation of regenerate bone in some patients, occurring largely, but not exclusively, in those who smoked heavily. Patients expressed high levels of satisfaction with the outcome, despite relatively modest improvements in pain and function, presumably because their longstanding and intractable nonunion had been treated. None the less, the degree of satisfaction correlated strongly with the degree of improvement in pain and function. We emphasise the importance of a multidisciplinary team in the assessment and support of patients undergoing long and demanding treatment. The Ilizarov method is valuable, but research is needed to overcome the problems of delayed maturation of the regenerate and slow or insecure healing of the docking site.

Adolescent↗
PubMed1997

1997 HIMSS/Hewlett-Packard leadership survey results. Survey results highlight infrastructure--the building block approach to IT strategy.

"Infrastructure" is the buzzword that emerged from the 1997 HIMSS/Hewlett-Packard Leadership Survey. Of the 1,220 survey respondents, 37 percent identified upgrading infrastructure as the most significant IT projects their organizations undertook over the last year. "In the past, organizations were not deliberately against building infrastructure; they just did not know what it takes," says researcher and survey analyst John Pollock, Princeton, N.J. "It is evident now they are looking more at the framework." Increasing pressure to achieve a competitive advantage has led to a real interest in integrating healthcare delivery systems, he explains.

Attitude of Health Personnel↗
PubMed1997

Healthcare IS industry top 100. HBOC tops out 100.

The Healthcare Informatics Top 100 ranks the leading information system software providers to the healthcare industry by revenues. Due to the limited focus of the healthcare IS industry, many Top 100 companies serve other markets in addition to IS or healthcare. Thus, to most accurately compare companies, we asked cross-industry companies and companies with non-IS specific offerings to separate out those revenues specific to healthcare information systems. For some companies this proved an impossible task. In such cases, we relied on estimated revenues provided by professional sources throughout the industry. (Such companies are marked by an asterisk on the Top 100 list). According to industry analyst Sheldon I. Dorenfest of Sheldon I. Dorenfest & Associates, Chicago, the healthcare information systems marketplace can be divided into three parts: sales of computer and networking equipment account for 62 percent of revenue, software and software associated management services account for 33 percent, and consultation and other management services account for 5 percent. The Healthcare Informatics Top 100 features companies offering software and software associated management services as primary source of revenue (this includes resales of hardware and networking equipment). Companies not eligible for the Top 100 include investment companies, and companies for which consulting, non-software management services, or hardware or medical equipment is the primary source of revenue.

Commerce↗
PubMed1996

Low-normal or excessive body mass index: newly identified and powerful risk factors for death and other complications with percutaneous coronary intervention.

Recognized risk factors account for only a small portion of the variance in the 4% to 10% incidence of major ischemic events associated with percutaneous coronary intervention. Body mass index (BMI) (body weight in kg/[height in m]2) is a clinically useful estimate of body fat and has been shown to correlate with mortality from several causes. We sought to evaluate the effect of BMI as a potential risk factor for the complications of percutaneous coronary intervention in 3,571 consecutive percutaneous coronary intervention patients treated at a single referral center. Patients were prospectively divided into the nonobese (BMI < or = 25), mildly obese (BMI 26-35), and very obese (BMI > 35), based on accepted definitions. Multiple logistic regression analyses were used to determine the correlates of major complications from 25 candidate variables, including BMI < or = 25 (n = 614 patients) and BMI > 35 (n = 275 patients), recorded prospectively in a relational database. Death occurred in 2.8% of the BMI < or = 25 group, in 3.7% of the BMI > 35 group, and in 0.9% of the BMI 26-34 group (p < 0.001), but there was no difference in the incidence of other ischemic events. Blood product transfusion was required in 12% of the BMI < or = 25 group, in 7% of the BMI 25-34 group, and in 8% of the BMI > 35% group (p = 0.003). Multivariate analysis, after adjustment for other significant correlates, demonstrated that both BMI < or = 25 (odds ratio [OR] = 2.7, p = 0.005) and BMI > 35 (OR = 7.4, p < 0.001) were independent correlates of death. Low-normal or high BMI is a newly described and powerful risk factor for in-hospital death after percutaneous coronary intervention.

Aged↗
PubMed1996

Activation of a yeast pseudo DNA methyltransferase by deletion of a single amino acid.

The biological methylation cytosine bases in DNA is central to such diverse phenomena as restriction and modification in bacteria, repeat induced point-mutation (RIPing) in fungi and for programming gene expression patterns in vertebrates. Structural studies on HhaI DNA methyltransferase, together with the sequence comparisons of around 40 cytosine-specific DNA methyltransferases, have recently provided a molecular framework for understanding the mechanism of action of the related group of enzymes that catalyse this base modification. There are, however, a number of organisms, including Saccharomyces cerevisiae, Schizosaccharomyces pombe and Drosophila melanogaster, which have no detectable DNA methylation. Here we report that the product of the pmt1 gene recently identified in S. pombe, which contains most of the primary structure elements of a typical cytosine-specific DNA methyltransferase, is catalytically inert owing to the insertion of a Ser residue between the Pro-Cys motif found at the active site of all such DNA methyltransferases. Following deletion of this Ser residue, catalytic activity is restored and, using a range of DNA binding experiments, it is shown that the enzyme recognises and methylates the sequence CC(A/T)GG, the same sequence that is modified by the product of the Escherichia coli dcm gene. The pmt gene of S. pombe therefore encodes a pseudo DNA methyltranferase, which we have called psiM.SpoI.

Base Sequence↗
PubMed1996

Sex differences in corticosteroid binding in the rat brain: an in vitro autoradiographic study.

Several previous studies have raised the possibility of sex differences in the distribution of corticosteroid receptors in the brain. The direction and magnitude of these differences have, however, remained controversial. In the present study, we have re-examined the concentrations of mineralocorticoid (MR) and glucocorticoid (GR) receptors in the brains of male and female rats at varying times (1 to 6 days) after combined gonadectomy (GDX) and adrenalectomy (ADX). Cytosol binding assays confirmed the presence of higher MR levels in short-term (3-day) GDX-ADX males. This difference disappeared by 6 days after surgery, as receptor levels in females rose to be equivalent to those in males. Using an improved in vitro autoradiographic method, the distribution of MR and GR was studied in males and females 3 days after GDX-ADX. The distribution of MR and GR in the brains of these rats was similar in the two sexes. MR binding in the male, however, was significantly greater than that in the female throughout the principal cell fields of the hippocampus. Measurements of circulating corticosterone levels at the time of GDX-ADX suggest that this sex difference may reflect a more rapid recovery of the MR system in males than in females following the stress-induced rise in corticosterone secretion occurring at the time of surgery.

Adrenal Cortex Hormones↗
PubMed1996

Noise levels in a cardiac surgical intensive care unit: a preliminary study conducted in secret.

Noise in hospitals frequently exceeds recommended levels and has detrimental psychological and physiological effects on patients and staff. The aim of this study was to record the noise levels within the cardiac surgical intensive care unit (CSICU) environment in secret. The device used was a CEL Instruments environmental noise meter concealed in a dummy box featuring temperature and humidity digital displays. It allowed greater than 16 hours recording time at a 1-minute resolution. The 24-hour period was covered by overlapping recordings. The data collected were downloaded onto a personal computer for analysis. The maximum sound level recorded was 100.9 decibel level (dBA), 1 min Lmax (the maximum sound level occurring in a 1-min period). The minimum sound level was 61.3 dBA 1 min Lmax. The continuous background noise was at its lowest at 57.5 dBA 1 min equivalent continuous sound pressure levels (Leq) and at its peak 77.3 dBA 1 min Leq. Noise in the CSICU was above the recommended levels for patients and staff well-being. Future studies will be designed to establish a correlation between sound levels and events.

Cardiac Surgical Procedures↗
PubMed1996

Treatment of refractory Wegener's granulomatosis with humanized monoclonal antibodies.

Conventional immunosuppression for systemic vasculitides is limited by substantial side-effects, cumulative drug toxicity and refractoriness in some patients. Six Wegener's granulomatosis patients who had been refractory to conventional therapy for at least 6 months, were treated with humanized monoclonal antibodies specific to lymphocyte CD52 or CD4 antigens. Diagnosis was on clinicopathological grounds, supported by the presence of autoantibodies to Proteinase 3. Histological evidence of persistent disease activity was obtained for each patient. Humanized monoclonal anti-CD52, with or without anti-CD4, was given intravenously up to 40 mg/day for up to 10 days. Remission, (programmed withdrawal of drug therapy without return of refractory disease) was achieved in all patients. Cytotoxic drugs were discontinued at the time of monoclonal antibody treatment and not used again; steroids were withdrawn gradually. Four patients relapsed at 1.5, 5, 10 and 18 months, and were treated successfully with further monoclonal antibody therapy alone. Three years after the study began, five patients are well; one patient died at surgery whilst in remission. Humanized monoclonal antilymphocyte antibodies may provide an effective treatment in patients with systemic vasculitis which is refractory to steroids or cytotoxic agents, or who are intolerant of these drugs.

Adoptive Transfer↗