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Biomedical subjects

S Evans

Publications and source records attributed to S Evans.

At least 37 records · Page 2Linked to original sources
PubMed2004

Predictors of attrition in HIV-positive subjects with peripheral neuropathic pain.

The objective of this paper was to identify predictors of attrition in a study designed to assess whether cognitive behavioural therapy (CBT) was more helpful than supportive therapy (SP) in reducing pain associated with peripheral neuropathy in HIV-positive patients. Sixty-one subjects were randomized into either CBT or SP for six weekly one-hour sessions. Twenty-eight subjects dropped out before week six. Demographic variables such as age, gender, ethnicity, socioeconomic status and level of education were not predictive of attrition. However, higher scores on the Hamilton Depression Inventory (HAM-D, 17-item) (t (59) = - 0.09, p<0.05) were predictive. These findings suggest that while dropouts were not more physically ill (e.g. CD4 counts, viral loads and opportunistic infections were not statistically higher), they reported greater psychological distress.

Cognitive Behavioral Therapy↗
PubMed2004

Home enteral feeding audit.

OBJECTIVE: To determine the main problems that families experience in the first month after their child is discharged from hospital on home enteral tube feeds (HETF) in terms of obtaining feed and equipment, managing tube feeding and accessing health professionals. METHODS: A multiple choice/short answer questionnaire was used to interview 81 parents/carers of children aged 0-16 years discharged from a supra regional children's hospital on HETF for the first time between December 2001 and August 2003. Questions addressed issues such as: contact with the home delivery company (HDC); delivery of feed and equipment; training; ability to access help; illnesses associated with tube feeding; and understanding of procedures post-discharge. RESULTS: The main problems identified were: delayed first deliveries (> or =7 days post-discharge; 47%); equipment missing from the first delivery (41%); difficulty obtaining a prescription from the general practitioner (GP) (17%); changing to different equipment post-discharge with minimal training on the new equipment (26%). CONCLUSIONS: There were many problems with delays in delivery of equipment, incorrect equipment and changing of equipment when patients were first discharged on HETF. Significant improvements are necessary in organization of home enteral feeding systems when patients are first discharged.

Adolescent↗
PubMed2004

Cadmium-induced apoptosis in oyster hemocytes involves disturbance of cellular energy balance but no mitochondrial permeability transition.

Exposure to environmentally prevalent heavy metals such as cadmium can have detrimental effects on a variety of commercially and ecologically important species such as oysters. Since Cd(2+) is known to induce apoptosis in immune cells of vertebrates, we have investigated the effects of this metal on isolated oyster hemocytes, the main cellular immune defense in mollusks. Enhanced apoptosis of these cells could conceivably create immunosuppressed conditions in these organisms and result in reduced disease resistance and increased opportunistic infection, resulting in decline of their populations. Cd(2+) exposure induced apoptosis in oyster hemocytes in a dose-dependent manner in the range of 10-100 micromol l(-1), as indicated by the translocation of phosphatidylserine to the outer leaflet of the plasma membrane. At higher concentrations (200-1000 micromol l(-1)), there was no further increase in apoptosis but a significant increase in the level of necrosis. In stark contrast to vertebrate immune cells, there was no decrease in the mitochondrial membrane potential or activation of caspases in response to Cd(2+) in the apoptotic range. Surprisingly, Cd(2+) exposure in this range did cause a significant decrease in intracellular ATP levels, indicating a severe disturbance of energy metabolism. Similarly, Cd(2+) exposure of isolated mitochondria resulted in partial uncoupling of mitochondria but no difference in mitochondrial membrane potential. The results demonstrate that the important environmental pollutant Cd(2+) induces apoptosis in oyster immune cells and does so through a mitochondria/caspase-independent pathway, suggesting that a novel, perhaps ancient, apoptotic pathway is active in these cells. Furthermore, it appears that the observed decrease in ATP production during apoptosis is not due to the loss of the mitochondrial proton-motive force but is more likely to be due to inhibition of the F(0)/F(1)-ATPase and/or mitochondrial ADP/ATP or substrate transport.

Adenosine Triphosphate↗
PubMed2003

Nissen fundoplication has a vagolytic effect on the lower esophageal sphincter.

BACKGROUND: Laparoscopic Nissen fundoplication is an increasingly utilized option for the treatment of gastroesophageal reflux disease (GERD). However, many questions remain as to the mechanism by which this operation prevents GERD in those without hiatal hernias or incompetent lower esophageal sphincters (LES). It is known that these patients experience reflux due to excess transient lower esophageal sphincter relaxations (TLESR), inappropriate and short-lived relaxation of the LES and crural diaphragm. The purpose of this study was to determine if Nissen fundoplication affects the neural pathways involved in the TLESR reflex. METHODS: Five dogs were anesthetized and intubated. Both vagal nerves and the right phrenic nerve were isolated. A continuous water perfusion manometric catheter was situated at the LES. The nerves were then electrically stimulated and the resultant pressure at the LES measured at baseline, and during and after an open Nissen fundoplication. RESULTS: The mean LES pressures before dissection, after esophago-gastric mobilization, and after fundoplication were 47 +/- 13 mmHg, 21 +/- 9 mmHg, and 14 +/- 4 mmHg, respectively. All differences were significant. There was no change noted in LES pressure with stimulation of either or both of the phrenic nerves without concomitant vagal stimulation. CONCLUSION: Nissen fundoplication may prevent GERD in those without a hiatal hernia or incompetent LES by disrupting the efferent vagal fibers to the LES. Such fibers mediate TLESR which are responsible for GERD in these patients.

Animals↗
PubMed2003

User involvement in UK cancer services: bridging the policy gap.

Recent UK government initiatives aim to increase user involvement in the National Health Service (NHS) in two ways: by encouraging service users to take an active role in making decisions about their own care; and by establishing opportunities for wider public participation in service development. The purpose of this study was to examine how UK cancer service users understand and relate to the concept of user involvement. The data were collected through in-depth interviews, which were analysed for content according to the principles of grounded theory. The results highlight the role of information and communication in effective user involvement. Perhaps more importantly, this study suggests that the concept of user involvement is unclear to many cancer service users. This paper argues the need for increased awareness and understanding of what user involvement is and how it can work.

Adult↗
PubMed2003

Endoluminal ultrasonography before retrograde endopyelotomy: can the results match laparoscopic pyeloplasty?

OBJECTIVE: To present the results of endopyelotomy using endoluminal ultrasonography (EUS) to identify crossing vessels, as the success rates of endopyelotomy are generally lower than pyeloplasty, especially in patients with crossing vessels. PATIENTS AND METHODS: Forty-one consecutive patients who underwent EUS before a planned retrograde endopyelotomy were analysed retrospectively. EUS was used to direct the endopyelotomy incision for patients with crossing vessels. Treatment was considered successful if the patient was asymptomatic and unobstructed or improved on renography. The results were compared to those from 18 patients treated by laparoscopic pyeloplasty, some of whom had undergone EUS. RESULTS: Crossing vessels were identified in 27 of the 41 patients (66%). Primary treatment consisted of endopyelotomy for 26 patients and laparoscopic pyeloplasty for 15. The overall success rate for 24 endopyelotomy patients with an adequate follow-up (mean 19 months) was 71%, with more success in patients with no crossing vessels (11 of 13 (85%) vs six of 11 (55%)). Of the 18 patients treated by laparoscopic pyeloplasty (mean follow-up 15.1 months) 17 were successful. CONCLUSION: The results for endopyelotomy were disappointing in patients with crossing vessels, despite using EUS. The results suggest that patients with crossing vessels should be treated by laparoscopic pyeloplasty. More data are needed to compare endopyelotomy with laparoscopic pyeloplasty in patients with no crossing vessels.

Adolescent↗
PubMed2003

Could ultrasonography be used by an anaesthetist to identify a specified lumbar interspace before spinal anaesthesia?

BACKGROUND: Insertion of a needle into the lumbar subarachnoid space may cause damage to the spinal cord. Current techniques to identify a safe interspace have limitations. Ultrasound was investigated as a means to improve anatomical accuracy. METHODS: Seventeen patients attending for elective magnetic resonance imaging (MRI) of the spine were studied. Ultrasonic identification of the L3-4 interspace was attempted by an anaesthetist and a marker was placed. A radiologist identified the anatomical location of the marker on the MRI scan. RESULTS: Thirteen out of 17 markers were at the L3-4 interspace; four were at the L2-3 interspace. CONCLUSIONS: These results suggest that ultrasonography may be a useful adjunct to safe subarachnoid anaesthesia.

Adult↗
PubMed2003

X-ray refraction effects: application to the imaging of biological tissues.

The purpose of this study was to explore the potential of refraction contrast X-ray imaging of biological tissues. Images of dissected mouse lungs, heart, liver and legs were produced using the medical beamline at the Elettra Synchrotron at Trieste, Italy. The technique used was diffraction enhanced imaging. This utilizes a silicon crystal positioned between the tissue sample and the detector to separate refracted X-rays from transmitted and scattered radiation by Bragg diffraction. The contrast in the images produced is related to changes in the X-ray refractive index of the tissues, resulting in remarkable clarity compared with conventional X-ray images based on absorption effects. These changes were greatest at the boundaries between different tissues, giving a marked edge enhancement effect and three-dimensional appearance to the images. The technique provides a way of imaging a property of biological tissues not yet exploited, and further studies are planned to identify specific applications in medical imaging.

Animals↗
PubMed2002

Potential role of endocrine gastrin in the colonic adenoma carcinoma sequence.

The role of hyper-gastrinaemia in the incidence of colonic cancer remains to be clarified. The aim of this study was to determine whether cholecystokinin-2 (CCK-2) receptor expression predicts the sensitivity of human colonic adenomas to the proliferative effects of serum hyper-gastrinaemia. Gene expression of the classical (74 kDa) CCK-2 receptor in human colonic adenoma specimens and cell lines, was quantified by real-time PCR. Western blotting, using a CCK-2 receptor antiserum, confirmed protein expression. A transformed human colonic adenoma was grown in SCID mice, with hyper-gastrinaemia induced by proton pump inhibitors. CCK-2 receptor blockade was achieved by using neutralising antiserum. Both human colonic adenoma cell lines and biopsies expressed CCK-2 receptor mRNA at levels comparable with CCK-2 receptor transfected fibroblasts and oxyntic mucosa. Western blotting confirmed immunoreactive CCK-2 receptor bands localised to 45, 74 and 82.5 kDa. Omeprazole and lansoprazole-induced hyper-gastrinaemia (resulting in serum gastrin levels of 34.0 and 153.0 pM, respectively) significantly increased the weight of the human adenoma grafts (43% (P=0.016) and 70% (P=0.014), respectively). The effect of hypergastrinaemia on tumour growth was reversed by use of antiserum directed against the CCK-2 receptor. Hyper-gastrinaemia may promote proliferation of human colonic adenomas that express CCK-2 receptor isoforms.

Adenocarcinoma↗
PubMed2002

Dynamic nature of early organ dysfunction determines outcome in acute pancreatitis.

BACKGROUND: All patients with organ dysfunction are currently classified as having severe acute pancreatitis. The aim of this study was to characterize the systemic inflammatory response syndrome (SIRS) and early organ dysfunction in patients with acute pancreatitis and the relationship with overall mortality. METHODS: Patients with predicted severe acute pancreatitis of less than 48 h duration had daily organ dysfunction scores and SIRS criteria calculated. These features were then correlated with outcome. RESULTS: Of 121 patients, 68 (56 per cent) did not develop organ dysfunction; only two of these patients died (mortality rate 3 per cent). Fifty-three (44 per cent) had early organ dysfunction, of whom 11 died (21 per cent). Organ dysfunction and persistent SIRS were both associated with an increased mortality rate, but on multivariate analysis only deteriorating organ dysfunction was an independent determinant of survival. CONCLUSION: Early organ dysfunction in acute pancreatitis usually resolves and in itself has no significant influence on mortality. In contrast, worsening organ dysfunction was associated with death in more than half of the patients (11 of 20); it is this group of patients who should be classified as having severe acute pancreatitis.

Acute Disease↗
PubMed2002

Changes in risk factors for cardiovascular disease with body fat loss in obese women.

BACKGROUND: Current guidelines for obesity management emphasize the improvements in health risks associated with weight losses of 5-10% initial weight. However, most of the data is derived from periods of acute weight loss and may not represent the true effect in the longer term or in obese but otherwise healthy individuals. This study examines the temporal changes in risk factors for cardiovascular disease with weight change over 52 weeks. METHODS: In total, 57 overweight women (age 43.7 +/- 9.1 years, mean BMI of 31.7 kg/m2, range 27.2-38.5 kg/m2) with no other significant medical history, entered a milk-based, low-energy weight loss programme for 12 weeks and were then monitored without further intervention until 52 weeks. Weight, fat mass, fasting plasma insulin, lipids and blood pressure were measured at 0, 12, 24 and 52 weeks. RESULTS: The mean weight change in sequential periods was -11.6% (p < 0.0001), +1.1% (p = 0.02) and +5.2% (p < 0.0001). The change from baseline to 1 year being -6.0% (p < 0.0001) an 11% (p < 0.0001) reduction in initial body fat mass. Initial weight loss (0-12 weeks) was positively correlated with greater longer term weight loss (0-52 weeks, r = 0.75, p < 0.0001) and not with weight regain (12-52 weeks, r = 0.14, p = 0.28). Despite significant improvements in insulin sensitivity, lipid profile and blood pressure (BP) with acute weight loss, in the group overall, only benefits in BP were maintained after 52 weeks. However, improvements in insulin sensitivity were sustained in those who maintained more than 5% weight loss, and those with higher baseline metabolic risk had greater benefits with weight loss. Change in waist circumference was better than BMI or fat mass in predicting improvements in metabolic risk in these obese women. CONCLUSIONS: This study suggests, in otherwise apparently healthy obese women, the rationale of targeting individuals most likely to benefit from weight management. Most importantly it highlights the need to focus on achieving initial weight losses of greater than 10% to maintain longer term losses of at least 5% and the associated health benefits.

Adipose Tissue↗
PubMed2002

The viral envelope is a major determinant for the induction of lymphoid and myeloid tumours by avian leukosis virus subgroups A and J, respectively.

Among the six envelope subgroups of avian leukosis virus (ALV) that infect chickens, subgroups A (ALV-A) and J (ALV-J) are the most pathogenic and widespread among commercial chicken populations. While ALV-A is predominantly associated with lymphoid leukosis (LL) and less frequently with erythroblastosis (EB), ALV-J mainly induces tumours of the myeloid lineage. In order to examine the basis for the lineage specificity of tumour induction by these two ALV subgroups, we constructed two chimeric viruses by substituting the env genes into the reciprocal proviral clones. The chimeric HPRS-103(A) virus carrying the subgroup A env gene is identical to ALV-J prototype virus HPRS-103 except for the env gene, and the chimeric RCAS(J) virus carrying the subgroup J env gene is identical to the parent replication-competent ALV-A vector RCAS except for the env gene. In experimentally inoculated chickens, HPRS-103(A) virus induced LL and EB similar to ALV-A isolates such as RAV-1, while RCAS(J) virus induced myeloid leukosis (ML) and EB, similar to ALV-J, suggesting that the env gene is the major determinant for the lineage-specific oncogenicity. There were genetic differences in susceptibility to tumour induction between line 0 and line 15(I) chickens, indicating that in addition to the env gene, other viral or host factors could also serve as determinants for oncogenicity. Induction of both LL and ML by the two chimeric viruses occurred through the activation of c-myc, while the EB tumours were induced by activation of the c-erbB oncogene.

Alpharetrovirus↗
PubMed2001

Ablation of Cypher, a PDZ-LIM domain Z-line protein, causes a severe form of congenital myopathy.

Cypher is a member of a recently emerging family of proteins containing a PDZ domain at their NH(2) terminus and one or three LIM domains at their COOH terminus. Cypher knockout mice display a severe form of congenital myopathy and die postnatally from functional failure in multiple striated muscles. Examination of striated muscle from the mutants revealed that Cypher is not required for sarcomerogenesis or Z-line assembly, but rather is required for maintenance of the Z-line during muscle function. In vitro studies demonstrated that individual domains within Cypher localize independently to the Z-line via interactions with alpha-actinin or other Z-line components. These results suggest that Cypher functions as a linker-strut to maintain cytoskeletal structure during contraction.

Actinin↗