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Biomedical subjects

E Ellis

Publications and source records attributed to E Ellis.

At least 19 recordsLinked to original sources
PubMed2007

Physical activity and health: evidence from a study of deprived communities in England.

This study aims to explore the relationship between physical activity levels and the self-reported health status of residents living in deprived communities in England. A cross-sectional interview survey was conducted in communities in receipt of funding from the New Deal for Communities (NDC) regeneration programme. A sample of 848 addresses was selected by random sampling from within each of the 39 NDC areas, and one adult from each household was selected for interview. A total of 19 574 residents were interviewed between July and October 2002. The main outcome measures were physical activity level and health status assessed using four self-reported health measures: health in the last 12 months, health change in the last 12 months, long-standing illness or disability and a mental health-related quality-of-life score. There are large regional and demographic variations in respect of NDC residents' physical activity levels. The areas with the lowest levels of physical activity are mainly located in northern industrial towns. Residents who did little or no physical activity were more than twice as likely to feel that their health was not good (adjusted OR 2.54, 95% CI 2.35-2.75).

Adolescent↗
PubMed2005

Reducing inequalities in access to health care: developing a toolkit through action research.

PROBLEM: Healthcare organisations are expected both to monitor inequalities in access to health services and also to act to improve access and increase equity in service provision. DESIGN: Locally developed action research projects with an explicit objective of reducing inequalities in access. SETTING: Eight different health care services in the Yorkshire and Humber region, including community based palliative care, general practice asthma care, hospital based cardiology clinics, and termination of pregnancy services. KEY MEASURES FOR IMPROVEMENT: Changes in service provision, increasing attendance rates in targeted groups. STRATEGIES FOR CHANGE: Local teams identified the population concerned and appropriate interventions using both published and grey literature. Where change to service provision was achieved, local data were collected to monitor the impact of service change. EFFECTS OF CHANGE: A number of evidence based changes to service provision were proposed and implemented with variable success. Service uptake increased in some of the targeted populations. LESSONS LEARNT: Interventions to improve access must be sensitive to local settings and need both practical and managerial support to succeed. It is particularly difficult to improve access effectively if services are already struggling to meet current demand. Key elements for successful interventions included effective local leadership, identification of an intervention which is both evidence based and locally practicable, and identification of additional resources to support increased activity. A "toolkit" has been developed to support the identification and implementation of appropriate changes.

Asthma↗
PubMed2002

The response of posteroanterior lumbar stiffness to repeated loading.

Lumbar posteroanterior (PA) responses are determined by manual examination and are used to guide treatment decisions and interpret changes in symptoms within and between treatments. Mechanical devices that simulate manual assessment have been developed to measure lumbar PA responses. The two variables used to describe lumbar PA responses to mechanical loading are stiffness coefficient K and displacement D30. The purpose of this study was to investigate the behaviour of lumbar PA responses with repeated loading over time. Lumbar PA responses at L4 were measured in 18 pain-free subjects using a mechanical device. Measurements were made for five consecutive loading cycles on three test occasions. The responses were compared between the five cycles within a single test occasion and between three test occasions. An identical procedure was also used to test a set of elastic springs for comparison. There was a significant increase in both stiffness coefficient K and displacement D30 between the first cycle and subsequent cycles of a single test occasion on human subjects. This response which demonstrates an increase in stiffness and displacement between the first and subsequent cycles can be considered a normal response to PA loading. PA stiffness remains constant over several tests both within one day and between days.

Adult↗
PubMed2002

GH is a regulator of IGF2 promoter-specific transcription in human liver.

The regulation of the insulin-like growth factor-II gene (IGF2) is complex and involves the usage of four promoters resulting in different 5' untranslated regions, but with a common translated product. The IGF2 gene product is a mitogenic and survival factor that has been suggested to be important for a normal fetal development and cancer. In this paper we present evidence suggesting that the human IGF2 gene is regulated by GH, and that this regulation occurs in a promoter-specific way. Three lines of evidence support this finding. First, in vivo data from patients treated with GH (one injection or daily injections for 5 consecutive days) showed an increase in the IGF2 P2 promoter derived transcript after acute treatment, and of the P4 promoter transcript after short-term treatment while the P1 promoter derived transcript did not show any significant change. Secondly, isolated human liver cells treated with GH for 2 h displayed an upregulation of the P2 promoter derived transcript. Thirdly, employing transfection experiments in GH-receptor positive CHO cells with P2 and P4 promoter-luciferase constructs, an upregulation by GH was evident, while a P1 promoter construct was unresponsive. We suggest that GH may be a physiological regulator of IGF2 in humans.

Analysis of Variance↗
PubMed2001

From brain to bile. Evidence that conjugation and omega-hydroxylation are important for elimination of 24S-hydroxycholesterol (cerebrosterol) in humans.

The brain is the almost exclusive site of formation of 24S-hydroxycholesterol in man, and there is a continuous flux of this oxysterol across the blood-brain barrier into the circulation. The hepatic metabolism of 24S-hydroxycholesterol was studied here by three different approaches: incubation of tritium-labeled 24S-hydroxycholesterol with human primary hepatocytes, administration of tritium-labeled 24S-hydroxycholesterol to a human volunteer, and quantitation of free and conjugated 24S-hydroxycholesterol and its neutral metabolites in ileocecal fluid from patients with ileal fistulae. 24S-Hydroxycholesterol as well as 24R-hydroxycholesterol were converted into bile acids by human hepatocytes at a rate of about 40% of that of the normal intermediate in bile acid synthesis, 7 alpha-hydroxycholesterol. There was also a conversion of 24S-hydroxycholesterol into conjugate(s) of 5-cholestene-3 beta,24S,27-triol at a rate similar to the that of conversion into bile acids. When administered to a human volunteer, labeled 24S-hydroxycholesterol was converted into bile acids at about half the rate of simultaneously administered labeled 7 alpha-hydroxycholesterol. Free, sulfated, and glucuronidated 24S-hydroxycholesterol and 5-cholestene-3 beta,24,27-triol were identified in ileocecal fluid. The excretion of these steroids was about 3.5 mg/24 h, amounting to more than 50% of the total estimated flux of 24S-hydroxycholesterol from the brain. It is concluded that 24S-hydroxycholesterol is a less efficient precursor to bile acids and that about half of it is conjugated and eliminated in bile as such or as a conjugate of a 27-hydroxylated metabolite. The less efficient metabolism of 24S-hydroxycholesterol may explain the surprisingly high levels of this oxysterol in the circulation and is of interest in relation to the suggested role of 24S-hydroxycholesterol as a regulator of cholesterol homeostasis.

Bile↗
PubMed2001

Ionizing radiation modulates vascular endothelial growth factor (VEGF) expression through multiple mitogen activated protein kinase dependent pathways.

We investigated the role of radiation-induced mitogen activated protein kinase (MAPK) pathway activity in the regulation of proliferation, cell survival and vascular endothelial growth factor (VEGF) production in primary astrocytes and in T9 and RT2 glioblastoma cells derived from Fisher 344 rats. In these cells, ionizing radiation (2 Gy) caused activation of the MAPK pathway which was blocked by specific inhibitor drugs. Blunting of radiation-induced MAPK activity weakly enhanced radiation-induced apoptosis 24 h after exposure in RT2 cells. Furthermore, blunting of MAPK activation weakly enhanced the ability of radiation to reduce RT2 cell growth in clonogenic growth assays. These findings argue that inhibition of MAPK signaling reduces proliferation and enhances cell killing by ionizing radiation in transformed astrocytes. Proliferation and survival of cancer cells has been linked in vivo to enhanced expression of angiogenic growth factors. Recently we demonstrated that the gene product of a novel rodent radiation-responsive gene, progression elevated gene 3 (PEG-3), could enhance vascular endothelial growth factor (VEGF) promoter activity in rodent fibroblasts, leading to increased VEGF protein levels and tumorigenic behavior in vivo. Thus PEG-3 and VEGF expression could be expected to directly correlate with the oncogenic potential of transformed cells. RT2 cells expressed more PEG-3 and VEGF protein than T9 cells, and were more tumorigenic in vivo than T9 cells. Radiation activated the PEG-3 promoter via MAPK signaling and ectopic over-expression of PEG-3 enhanced both basal MAPK activity and basal VEGF promoter activity. Basal MAPK activity partially correlated with basal VEGF promoter activity and VEGF protein levels in primary astrocytes, T9 and RT2 cells. Radiation increased the activity of the VEGF promoter and VEGF protein levels in primary astrocytes, T9 and RT2 cells which were dependent upon MAPK function. Furthermore, inhibition of AP-1 transcription factor signaling by dominant negative c-Jun (TAM67) also significantly reduced basal, and to a lesser extent radiation-induced, VEGF promoter function in RT2 cells. Collectively, our data demonstrate that radiation-induced MAPK signaling can both protect cells from radiation-induced cell death as well as enhance protein levels of pro-angiogenic factors such as VEGF. Enhanced VEGF expression in RT2 cells may be mediated via MAPK and JNK pathway signaling which converges upon the AP-1 transcription factor complex.

Amino Acid Chloromethyl Ketones↗
PubMed2001

Primary cultures of human hepatocytes but not HepG2 hepatoblastoma cells are suitable for the study of glycosidic conjugation of bile acids.

To define the role of glycosidic conjugation of bile acids in humans, an in vitro model system is desirable. We studied the formation of glycosidic conjugates of bile acids in primary cultures of human hepatocytes, isolated from organ donor liver, and the human hepatoblastoma cell line, HepG2. Cells were incubated with 100 microM bile acids (chenodeoxycholic, CDCA; hyodeoxycholic, HDCA; and isoursodeoxycholic acids, isoUDCA) and 1-2 mM uridine diphosphoglycosides (UDP-glucose, UDP-Glc; UDP-glucuronic acid, UDP-GlcA, and UDP-N-acetylglucosamine, UDP-GlcNAc), and octyl glucoside. Media were analysed by electrospray-/gas chromatography-mass spectrometry and electrospray with collision induced dissociation. Primary cultures of human hepatocytes formed glycosidic bile acid conjugates with UDP-sugars (6alpha-Glc-HDCA, 6alpha-GlcA-HDCA, and 7beta-GlcNAc-isoUDCA) and octyl glucoside as sugar donors (3alpha-Glc-CDCA). HDCA was completely metabolised to either Glc-HDCA, a compound yet not found in vivo, or GlcA-HDCA. No glycosidic bile acid conjugate was found in media from experiments with HepG2. Thus, primary cultures of human hepatocytes, but not HepG2, are suitable in vitro systems for the study of glycosidic bile acid conjugation reactions.

Acetylglucosamine↗
PubMed2001

The use of a pressure manometer enhances student physiotherapists' performance during manual hyperinflation.

The purpose of this study was to determine the effect of using a pressure manometer on the delivery of target airway pressures during manual hyperinflation by student physiotherapists in the laboratory and clinical environments. Manual hyperinflations were delivered under control and feedback conditions where the feedback condition involved manual hyperinflation with a pressure manometer. Compared with control conditions, the availability of a manometer significantly decreased the mean absolute error (9.5 +/- 0.9 cm H2O to 1.4 +/- 0.2 cm H2O) and mean variable error (2.2 +/- 0.3 cm H2O to 1.3 +/- 0.1cm H2O) of peak airway pressures during manual hyperinflation. In addition, the availability of a manometer negated the influence of environment on accuracy. Therefore, the availability of a pressure manometer provided an effective clinical tool that was easily used to provide feedback regarding the peak airway pressures delivered during manual hyperinflation.

Adult↗
PubMed2001

Bite forces after open or closed treatment of mandibular condylar process fractures.

PURPOSE: This study compared maximum voluntary bite forces in patients who received either open or closed treatment for fractures of the mandibular condylar process. PATIENTS AND METHODS: One hundred fifty-five patients (127 male, 28 female) with unilateral fractures of the mandibular condylar process (91 treated closed and 64 treated open) were included in this study. Maximum voluntary bite forces were measured at 6 weeks, 6 months, and 1, 2, and 3 years after fracture. At each trial, unilateral maximum voluntary bite force was measured at 4 different tooth positions bilaterally using a standard transducer. Electromyography (EMG) of the masseter muscles was also recorded during the bite force measurements, and ratios of the working/balancing side EMG were calculated. Analysis of the data was performed using standard statistical methods. RESULTS: The only significant difference between the 2 samples was in the level of fractures on the condylar process. No patients treated open had fractures of the "head" of the condylar process, whereas there were 11 in the group treated closed. No differences were observed in maximum voluntary bite forces between the 2 treatment groups at any time period, or were there correlations between bite force magnitude and location of the fracture, displacement of the fracture, or any other variable studied. Both groups showed a significant recovery of maximum bite force from the 6-week to the 6-month testing session. For both groups, working/balancing EMG ratios were significantly greater when subjects were biting on the side opposite the fracture. When biting on that side, the working/balancing EMG ratios were higher in the closed treatment group, but the difference did not reach significance. CONCLUSIONS: Maximum voluntary bite forces in patients treated for mandibular condylar process fractures do not differ significantly when treatment is open or closed. Neuromuscular adaptations to the fractured mandibular condylar process occur in both groups.

Adolescent↗
PubMed2001

The relationship between surgical changes in dentofacial morphology and changes in maximum bite force.

PURPOSE: This study determined whether patients with greater surgical changes, and presumably greater normalization of their skeletal morphology, showed greater increases in their maximum voluntary bite forces after orthognathic surgery. PATIENTS AND METHODS: A total of 104 adult patients (32 males and 72 females) treated with 1 of 8 different orthognathic surgical procedures were examined. Patients' presurgical and postsurgical morphologic and biomechanical measurements were taken from lateral cephalograms. Measurements known to be related to maximum bite force were used in the analysis. Patients' presurgical and postsurgical maximum bite forces were measured at 8 tooth positions (ie, right and left incisors, canines, premolars and molars). RESULTS: Presurgical and postsurgical morphology and biomechanics variables were strongly correlated with each other, suggesting that orthognathic surgery produced relatively little change in patients' overall craniofacial form. Maximum voluntary bite forces were primarily correlated with variables relating to jaw size-both before and after surgery. No correlations were noted between the increases in maximum voluntary bite forces and surgically produced changes in skeletal morphology and the biomechanics variables. CONCLUSIONS: Factors other than surgically produced changes in skeletal morphology are responsible for increases in maximum voluntary bite force after orthognathic surgery.

Adult↗
PubMed2001

Portrait of the physiotherapy profession.

As a profession integral to health promotion, prevention, acute care and rehabilitation physiotherapy plays an essential role in the health care system. This paper explores the nature of physiotherapy, the role of physiotherapy in health care, the practice of physiotherapy internationally, the education of physiotherapists, the regulation of physiotherapy practice and the maintenance of practice standards.

Allied Health Occupations↗
PubMed2001

The challenges of conducting clinical research: one research team's experiences.

Conducting clinical research is an exciting and a rewarding endeavor. Each project is unique and, because of this uniqueness, research studies require considerable planning. Regardless of all the upfront planning, challenges will occur throughout the life of the study. Clinical research projects are rife with obstacles that range from the lack of administrative and physician support to subject attrition. Some of the challenges, such as subject dropout, are not unexpected, whereas other unanticipated issues can blindside a research team. This case study examines several such challenges experienced in one longitudinal study and presents the solutions engineered by the research team to keep the project on track.

Cardiac Output, Low↗
PubMed2001

Clinical implications of sex in acute temporomandibular disorders.

BACKGROUND: Previous research on temporomandibular disorders, or TMDs, has been somewhat limited, with studies having low numbers of subjects, restricting the focus to women or looking at patients already diagnosed with chronic TMD. Because early intervention is beneficial, it is important to understand the symptoms that men and women have in the acute stage of TMD. METHODS: A total of 233 patients (161 women, 72 men) with acute TMD symptoms were assessed with a battery of biopsychosocial measures. Patients were diagnosed as having TMD on the basis of research diagnostic criteria, or RDC, or RDC, for TMD. After six months, patients were reassessed to determine whether they continued to have pain, thus classifying them as having chronic TMD. The authors found that 153 patients (47 men, 106 women) had developed a chronic condition, while 80 patients (25 men, 55 women) no longer reported pain (nonchronic). RESULTS: Female and male patients who developed chronic TMD differed significantly from patients who had acute symptoms that subsided. Women who developed chronic TMD exhibited significantly more psychosocial distress and impairment than women who did not develop chronic TMD, in terms of Diagnostic and Statistical Manual, Fourth Edition, or DSM-IV, diagnoses; Beck Depression Inventory, or BDI, scores; Minnesota Multiphasic Personality Inventory scores; Multidimensional Pain Inventory, or MPI, scores; and physical and psychological measures assessed with the RDC for TMD. Men who developed chronic TMD differed significantly from men who did not develop chronic TMD, in that they exhibited more impairment in terms of DSM-IV diagnoses and BDI and RDC measures. CONCLUSIONS: These findings provide evidence that significant differences exist between men and women in regard to acute TMD symptoms. CLINICAL IMPLICATIONS: The biopsychosocial differences between men and women suggest that some treatments may be more beneficial for women than for men.

Acute Disease↗
PubMed2000

Mechanical injury alters volume activated ion channels in cortical astrocytes.

UNLABELLED: Although astrocytic swelling is likely to mediate brain edema and high ICP after traumatic brain injury, the mechanism is not understood. We employed whole cell patch clamp electrophysiology and a stretch injury model to understand whether volume regulating ion currents are altered following cell injury. Mixed rat astrocytes and neurons were co-cultured on deformable silastic membranes. Mild-moderate cell injury was produced using a timed pulse of pressurized air to deform the silastic substrates by 6.5 mm. Then, ion currents were recorded with patch clamp methods. Cells were held at -65 mV and were stepped to +10 mV to monitor current changes. RESULTS: In unstretched astrocytes, small amplitude currents were obtained under isotonic conditions. Hypotonic solution activated an outwardly-rectifying current which reversed near -40 mV. This current resembled a previously reported anion current whose activation may restore cell volume by mediating a net solute efflux. In contrast, stretch injured cells exhibited a large amplitude, nonrectifying current. This current was not due to non-specific ionic leakage, since it was fully suppressed by the cation channel blocker gadolinium. Activation of novel stretch-activated cation currents may exacerbate cell swelling in injured astrocytes. Stretch injured astrocytes thus express a dysfunctional cation current as opposed to an osmoregulatory anion current. This mechanism, if present in vivo, may contribute to the cytotoxic swelling seen after traumatic brain injury.

Animals↗
PubMed2000

Open treatment of condylar process fractures: assessment of adequacy of repositioning and maintenance of stability.

PURPOSE: This study was designed to determine how well fractured condylar processes were reduced and the stability of the internal fixation in a group of patients whose fractures were treated by open reduction. PATIENTS AND METHODS: Sixty-one patients treated by open reduction and internal fixation for unilateral condylar process fractures were studied prospectively using Towne's and panoramic radiographs. The radiographs were made before surgery, and immediately, 6 weeks, and 6 months postoperatively. The images were traced and digitized, and the position of the fractured condylar process was statistically compared with the position of the nonfractured condylar process in both the coronal and sagittal planes. Additionally, 2 observers examined the images and assessed these same 2 factors. RESULTS: After surgery, the difference in position between the fractured and nonfractured sides averaged less than 2 degrees (not significantly different), indicating good reduction of the fractures. However, subsequently, between 10% and 20% of condylar processes had postsurgical changes in position of more than 10 degrees. CONCLUSIONS: This study showed that it is possible to anatomically reduce the fractured condylar process, but changes in position of the condylar fragment may then result from a loss of fixation.

Bone Plates↗
PubMed2000

Morphologic and biomechanical correlates with maximum bite forces in orthognathic surgery patients.

PURPOSE: The purpose of this study was to determine which factors of craniofacial morphology best predict maximum bite forces and jaw muscle strength (based on [electromyogram] EMG/force slopes) in patients selected for various orthognathic surgical procedures. These factors were then compared for their ability to separate orthognathic surgery patients by their clinical diagnosis. PATIENTS AND METHODS: Standard lateral cephalograms were taken of 121 orthognathic surgery patients (before treatment) and 80 control subjects to establish multivariate sagittal and biomechanical factors of craniofacial form. Maximum and submaximal bite forces were recorded at 8 tooth positions for each subject. EMG activity was recorded for 3 pairs of muscles (anterior temporalis, posterior temporalis, and superficial masseter) during the isometric bites. The EMG and bite force measurements were used to calculate EMG/force slopes as a measure of jaw muscle strength. The study looked for significant correlations between the morphologic factors and maximum bite force or jaw muscle strength. RESULTS: Factor analysis determined 12 sagittal and 6 biomechanical factors. However, only 3 of the sagittal and 4 of the biomechanical factors were significantly correlated with maximum bite force or jaw muscle strength. Factors reflecting jaw size were correlated with maximum bite forces and jaw muscle strength but generally did not separate patient groups. The factor most strongly correlated with maximum bite forces separated patients by their relative difference between anterior and posterior facial height. The factor for anteroposterior maxillomandibular discrepancies was not correlated with maximum bite force or jaw muscle strength. CONCLUSIONS: Many cephalometric measurements used to diagnose craniofacial deformities and to assign patients to particular orthognathic surgical procedures are not correlated with maximum bite forces or jaw muscle strength. Only measurements reflecting relative differences between anterior and posterior facial height are both strongly correlated with maximum bite force and reflect assignment of surgical procedures.

Adult↗