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J Evans

Publications and source records attributed to J Evans.

At least 37 records · Page 2Linked to original sources
PubMed2005

Reaction of SO2 with AuCeO2(111): importance of O vacancies in the activation of gold.

Synchrotron-based high-resolution photoemission was used to study the adsorption and chemistry of SO(2) on AuCeO(2)(111) and AuO(x)CeO(2) surfaces. The heat of adsorption of the molecule on Au nanoparticles supported on stoichiometric CeO(2)(111) was 4-7 kcalmol larger than on Au(111). However, there was negligible dissociation of SO(2) on the AuCeO(2)(111) surfaces. The full decomposition of SO(2) was observed only after introducing O vacancies in the ceria support. AuO(x)CeO(2) surfaces were found to be much less chemically active than AuCeO(2)(111) or AuCeO(2-x)(111) surfaces. The active sites in {Au + AuO(x)}ceria catalysts should involve pure gold nanoparticles in contact with O vacancies.

Journal Article↗
PubMed2005

Positron emission tomography does not add to computed tomography for the diagnosis and staging of pancreatic cancer.

BACKGROUND: Positron emission tomography (PET) has been proposed for pancreatic cancer diagnosis and staging. METHODS: 112 patients with suspected pancreatic cancer underwent 18F-fluoro-2-deoxy-D-glucose gamma camera PET and computed tomography (CT), of whom 62 also had laparoscopic ultrasonography and 70 underwent abdominal exploration for potential resection. The final diagnosis was malignancy in 78 and benign disease in 34 patients (25 with chronic pancreatitis). RESULTS: The diagnostic sensitivity and specificity for PET were 73 and 60% compared to 89 and 65% for CT respectively (Cohen's kappa = 0.59). In 30 patients CT was equivocal with cancer in 14 and benign disease in 16. PET correctly diagnosed 13 of these patients (cancer in 6 and benign disease in 7), interpreted 4 as equivocal (cancer in 3 and benign disease in 1) but was incorrect in the remaining 13 patients (cancer in 5 and benign disease in 8). The sensitivity and specificity for detecting small volume metastatic disease were 20 and 94% for CT and 22 and 91% for PET, respectively. CONCLUSION: PET had a similar accuracy to that of CT for imaging pancreatic cancer but it did not provide any additional information in patients with equivocal CT findings and currently would seem of little benefit for the staging of pancreatic cancer.

Adult↗
PubMed2005

The successful treatment of chylous effusions in malignant disease with octreotide.

Chylous effusions in adults are commonly associated with malignant disease. Although the condition is rare, their occurrence presents a significant management problem. A review of the literature demonstrates the high mortality of this condition in the past from cachexia and infection or after surgical attempts at correction. The first report of somatostatin use in chylous effusions was a decade ago. Since 2000, case reports of successful treatment in infants and neonates with intravenous somatostatin or octreotide have been published. For adults, few reports exist. We describe a case series of seven patients, all with malignancy. In each case, there was a systematic approach to treatment using subcutaneous octreotide and a fat-free diet, resulting in complete resolution of the condition. Although no guidelines are available for the management of chylous effusions, our non-invasive approach avoided lymphangiogram, surgery and allowed early discharge.

Aged↗
PubMed2005

HMG-CoA reductase inhibitors (statins) decrease MMP-3 and MMP-9 concentrations in abdominal aortic aneurysms.

BACKGROUND: An imbalance in matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) are implicated in AAA formation. 3-Hydroxy-3-methylglutaryl coenzyme-A reductase inhibitors (statins) are known to reduce MMP levels. The aim of this study was to investigate the in vivo effect of statins on MMP levels in AAA. METHODS: Infra-renal aortic biopsies were obtained from the anterior sac of 63 patients undergoing asymptomatic repair. Seventeen patients were taking a statin pre-operatively, while 46 were not. The concentrations of MMP-1, -2, -3, -8, -9, -13, TIMP-1 and TIMP-2 were quantified using ELISA. RESULTS: There was no difference in the concentration of MMP-1, -2, -8, -13, TIMP-1 or -2 in patients taking versus not taking a statin pre-operatively. In contrast levels of MMP-9 and MMP-3 were significantly lower in patients taking a statin. CONCLUSIONS: These data demonstrate that statins decrease MMP-9 and MMP-3 levels and represent a potential pharmacotherapy in established AAA.

Aged↗
PubMed2005

Early and late complications after pancreatic necrosectomy.

BACKGROUND: Surgery for pancreatic necrosis is associated with a high morbidity and mortality. The aim of this study was to review the incidence of early and late complications after pancreatic necrosectomy in a large contemporary series of patients. METHODS: The clinical outcomes of 88 patients who underwent pancreatic necrosectomy between 1997 and 2003 were reviewed. RESULTS: The median age was 55.5 (range, 18-85) years, 54 (61%) were males, 68 (77%) had primary pancreatic infection, 71 (81%) had >50% necrosis, and the median admission Acute Physiology and Chronic Health Evaluation score was 9 (range, 1-21). Median time to surgery was 31 (range, 1-161) days; 47 patients underwent minimally invasive necrosectomy and 41 open necrosectomy; 81 (92%) of patients had complications postoperatively, and 25 (28%) died. Multiorgan failure (odds ratio = 3.4, P = .05) and hemorrhage (odds ratio = 6.1, P = .03) were the only independent predictors of mortality. During a median follow-up of 28.9 months, 39 (62%) of 63 surviving patients had one or more late complications: biliary stricture in 4 (6%), pseudocyst in 5 (8%), pancreatic fistula in 8 (13%), gastrointestinal fistula in 1 (2%), delayed collections in 3 (5%), and incisional hernia in 1 (2%); intervention was required in 10 (16%) patients. Sixteen (25%) of 63 surviving patients developed exocrine insufficiency, and 19 (33%) of 58 without prior diabetes mellitus developed endocrine insufficiency. CONCLUSIONS: Almost all patients undergoing necrosectomy developed significant early or late complications or both. Multiorgan failure and postoperative hemorrhage were independent predictors of mortality. Long-term follow-up was important because 62% developed complications, and 16% of those with complications required surgical or endoscopic intervention.

APACHE↗
PubMed2005

Isolation and characterization of strains of Flavobacterium columnare from Brazil.

Flavobacterium columnare is an important pathogen of freshwater fish, implicated in skin and gill disease, often causing high mortality. An outbreak of skin disease in fingerling and adult Nile tilapia, Oreochromis niloticus (L.), cultivated in a recirculation system, was investigated. Four strains were isolated and characterized by biochemical reactions, enzyme production, fatty acid profile and analysis of the 16S-23S rDNA intergenic spacer region. All strains were identified as F. columnare. Experimental infection assays with one of these strains (BZ-5-02) were conducted and pathogenicity (by intramuscular route) was demonstrated in Nile tilapia and channel catfish, Ictalurus punctatus (Rafinesque). This is the first report of characterization of Brazilian strains of F. columnare.

Animals↗
PubMed2005

Outcome of pregnancy in a woman with an increased body mass index.

OBJECTIVE: To show the increased risk of adverse outcomes in labour and fetomaternal morbidity in obese women (BMI > 30). DESIGN: A population-based observational study. SETTING: University Hospital of Wales. The study sample was drawn from the Cardiff Births Survey, a population-based database comprising of a total of 60,167 deliveries in the South Glamorgan area between 1990 and 1999. Population Primigravid women with a singleton uncomplicated pregnancy with cephalic presentation of 37 or more weeks of gestation with accurate information regarding height and weight recorded at the booking visit (measured by the midwives) were included in the study. METHODS: Comparisons were made between women with a body mass index of 20-30 and those with more than 30. SPSS version 10 was used for statistical analysis. Student's t test, chi(2) and Fisher's exact tests were used wherever appropriate. MAIN OUTCOME MEASURES: Labour outcomes assessed were risk of postdates, induction of labour, mode of delivery, failed instrumental delivery, macrosomia and shoulder dystocia. Maternal adverse outcomes assessed were postpartum haemorrhage, blood transfusion, uterine and wound infection, urinary tract infection, evacuation of uterus, thromboembolism and third- or fourth-degree perineal tears. Fetal wellbeing was assessed using Apgar <7 at 5 minutes, trauma and asphyxia, cord pH < 7.2, babies requiring neonatal ward admissions, tube feeding and incubator. RESULTS: We report an increased risk [quoted as odds ratio (OR) and confidence intervals CI)] of postdates, 1.4 (1.2-1.7); induction of labour, 1.6 (1.3-1.9); caesarean section, 1.6 (1.4-2); macrosomia, 2.1 (1.6-2.6); shoulder dystocia, 2.9 (1.4-5.8); failed instrumental delivery, 1.75 (1.1-2.9); increased maternal complications such as blood loss of more than 500 mL, 1.5 (1.2-1.8); urinary tract infections, 1.9 (1.1-3.4); and increased neonatal admissions with complications such as neonatal trauma, feeding difficulties and incubator requirement. CONCLUSION: Obese women appear to be at risk of intrapartum and postpartum complications. Induction of labour appears to be the starting point in the cascade of events. They should be considered as high risk and counselled accordingly.

Adult↗
PubMed2005

Surgery in the treatment of acute pancreatitis--minimal access pancreatic necrosectomy.

Between 5% and 10% of patients with acute pancreatitis will develop infected pancreatic necrosis. Traditional open surgery for this condition carries a mortality rate of up to 50%, and therefore a number of less invasive techniques have been developed, including radiological drainage and a minimal access retroperitoneal approach. No randomised controlled trials have been published which compare these techniques. Indications for minimal access surgery are the same as for open surgery, i.e. infected pancreatic necrosis or failure to improve with extensive sterile necrosis. Access is obtained to the pancreatic necrosis via the left loin and necrosectomy performed using an operating nephroscope, and this often requires several procedures to remove all necrotic tissue. The cavity is continuously irrigated on the ward in between procedures. The results of this approach are encouraging, with less systemic upset to the patient, a lower incidence of post-operative organ failure when compared with open surgery, and a reduced requirement for ITU support. There is also a trend towards a lower mortality rate, although this does not reach statistical significance on the data published so far. Current evidence suggests that a minimal access approach to pancreatic necrosis is feasible, well tolerated and beneficial for the patient when compared with open surgery.

Dilatation↗
PubMed2005

Overexpression of telomerase confers growth advantage, stress resistance, and enhanced differentiation of ESCs toward the hematopoietic lineage.

Embryonic stem cells (ESCs) are capable of extended self-renewal and maintenance of pluripotency even after many population doublings. This is supported by high levels of telomerase activity and enhanced antioxidant protection in ESCs, both of which are downregulated during differentiation. To examine the role of telomerase for ESC self-renewal and differentiation, we overexpressed the reverse transcriptase subunit (Tert) of murine telomerase in ESCs. Increased telomerase activity enhances the self-renewal ability of the Tert-overexpressing ESCs, improves their resistance to apoptosis, and increases their proliferation. The differentiated progeny of wild-type ESCs express little Tert and show shortening of telomeric overhangs. In contrast, the progeny of Tert-overexpressing ESCs maintain high telomerase activity, as well as the length of G-rich overhangs. In addition, these cells accumulate lower concentrations of peroxides than wild-type cells, implying greater resistance to oxidative stress. Finally, differentiation toward hematopoietic lineages is more efficient as a result of the continued expression of Tert. Microarray analysis revealed that overexpression of Tert altered expression of a variety of genes required for extended self-renewal and lifespan. Our results suggest that telomerase functions as a "survival enzyme" in ESCs and its differentiated progeny by protecting the telomere cap and by influencing the expression patterns of stress response and defense genes. This results in improved proliferation of ESCs and more efficient differentiation, and these results might have profound consequences for stem cell-replacement therapies.

Animals↗
PubMed2004

Diffusion tensor imaging for the assessment of upper motor neuron integrity in ALS.

BACKGROUND: High angular resolution diffusion tensor imaging (HARD) is an MRI technique that exploits the mobility of water molecules to yield maps of structural order and directionality of white matter tracts with greater precision than six-direction diffusion tensor imaging (DTI) schemes. OBJECTIVE: To assess whether HARD is more sensitive than conventional MRI or neurologic assessment in detecting the upper motor neuron (UMN) pathology of patients with ALS. METHODS: Twenty-five patients with definite UMN clinical signs and 23 healthy volunteers underwent conventional MRI. HARD datasets were collected from a subset of these participants plus four patients with isolated lower motor neuron (LMN) signs. ALS symptom severity was assessed by a neurologist, the conventional MR images were reviewed by neuroradiologists, and the DTI maps were subject to quantitative region of interest analysis. RESULTS: Motor cortex hypointensity on T2-weighted images and corona radiata hyperintensity on proton density-weighted images distinguished patients with UMN involvement from volunteers with 100% specificity, but only 20% sensitivity. Fractional anisotropy (FA) was reduced in the posterior limb of the internal capsule in patients with UMN involvement compared to volunteers. A FA threshold value with a sensitivity of 95% to detect patients with ALS (including those with isolated LMN signs) had a specificity of 71%. CONCLUSIONS: High angular resolution diffusion tensor imaging may be more sensitive than conventional MRI or neurologic assessment to the upper motor neuron (UMN) pathology of ALS, but it lacks the specificity required of a diagnostic marker. Instead, it is potentially useful as a quantitative tool for monitoring the progression of UMN pathology.

Adult↗
PubMed2004

Fungal infection but not type of bacterial infection is associated with a high mortality in primary and secondary infected pancreatic necrosis.

INTRODUCTION: Knowledge of microbiology in the prognosis of patients with necrotizing pancreatitis is incomplete. AIM: This study compared outcomes based on primary and secondary infection after surgery for pancreatic necrosis. METHOD: From a limited prospective database of pancreatic necrosectomy, a retrospective case note review was performed (October 1996 to April 2003). RESULTS: 55 of 73 patients had infected pancreatic necrosis at the first necrosectomy. 25 of 47 patients had resistant bacteria to prophylactic antibiotics (n = 21) or did not receive prophylactic antibiotics (n = 4), but this was not associated with a higher mortality (9 of 25) compared to those with sensitive organisms (4 of 22). Patients with fungal infection (n = 6) had a higher initial median (95% CI) APACHE II score compared to those without (11 (9-13) verus 8.5 (7-10), p = 0.027). Five of six patients with fungal infection died compared to 13 of 47 who did not (p = 0.014). With the inclusion of secondary infections 21 (32%) of 66 patients had fungal infection with 10 (48%) deaths compared to 11 (24%) of 45 patients without fungal infection (p = 0.047). CONCLUSION: Whether associated with primary or secondary infected pancreatic necrosis, fungal but not bacterial infection was associated with a high mortality.

Bacterial Infections↗
PubMed2004

Dynamic cardiorespiratory interaction during head-up tilt-mediated presyncope.

In 28 healthy adults, we compared the dynamic interaction between respiration and cerebral autoregulation in 2 groups of subjects: those who did and did not develop presyncopal symptoms during 70 degrees passive head-up tilt (HUT), i.e., nonpresyncopal (23 subjects) and presyncopal (5 subjects). Airflow, CO2, cerebral blood flow velocity (CBF), ECG, and blood pressure (BP) were recorded. To determine whether influences of mean BP (MBP) and systolic SP (SBP) on CBF were altered in presyncopal subjects, coherencies and transfer functions between these variables and mean and peak CBF (CBFm and CBFp) were estimated. To determine the influence of end-tidal CO2 (ETco2) on CBF, the relative CO2 reactivity (%change in CBFm per mmHg change in ETco2) was calculated. We found that in presyncopal subjects before symptoms during HUT, coherence between SBP and CBFp was higher (P=0.02) and gains of transfer functions between BP (MBP and SBP) and CBFm were larger (MBP, P=0.01; SBP, P=0.01) in the respiratory frequency region. In the last 3 min before presyncope, presyncopals had a reduced relative CO2 reactivity (P=0.005), likely a consequence of the larger decrease in ETco2. We hypothesize that the CO2-mediated increase in resistance attenuates autoregulation such that the relationship between systemic and cerebral hemodynamics is enhanced. Our results suggest that an altered cardiorespiratory interaction involving cerebral hemodynamics may contribute in the cascade of events during tilt that culminate in unexplained syncope.

Adult↗
PubMed2004

Hereditary pancreatic endocrine tumours.

The two main types of hereditary pancreatic neuroendocrine tumours are found in multiple endocrine neoplasia type 1 (MEN-1) and von Hippel-Lindau disease (VHL), but also in the rarer disorders of neurofibromatosis type 1 and tuberous sclerosis. This review considers the major advances that have been made in genetic diagnosis, tumour localization, medical and surgical treatment and palliation with systemic chemotherapy and radionuclides. With the exception of the insulinoma syndrome, all of the various hormone excess syndromes of MEN-1 can be treated medically. The role of surgery however remains controversial ranging from no intervention (except enucleation for insulinoma), intervening for tumours diagnosed only by biochemical criteria, intervening in those tumours only detected radiologically (1-2 cm in diameter) or intervening only if the tumour diameter is > 3 cm in diameter. The extent of surgery is also controversial, although radical lymphadenectomy is generally recommended. Pancreatic tumours associated with VHL are usually non-functioning and tumours of at least 2 cm in diameter should be resected. Practice guidelines recommend that screening in patients with MEN-1 should commence at the age of 5 years for insulinoma and at the age of 20 years for other pancreatic neuroendocrine tumours and variously at 10-20 years of age for pancreatic tumours in patients with VHL. The evidence is increasing that the life span of patients may be significantly improved with surgical intervention, mandating the widespread use of tumour surveillance and multidisciplinary team management.

Endocrine Gland Neoplasms↗
PubMed2004

The role of orthodontics and oral and maxillofacial surgery in the management of obstructive sleep apnoea - a single case report.

Obstructive sleep apnoea (OSA) is a potentially fatal breathing disorder, yet is widely under-diagnosed. It is a multi-factorial condition associated with high morbidity, a degree of mortality and is associated with an increase risk of car crashes. A case is presented which demonstrates the inter-disciplinary approach to this condition and the successful treatment through mandibular advancement by orthodontic means followed by orthognathic surgery. The experience of this patient illustrates the importance of the disciplines of orthodontics and oral and maxillofacial surgery in the multi-disciplinary management of these patients.

Continuous Positive Airway Pressure↗
PubMed2004

A postal survey of hydrosalpinx management prior to IVF in the United Kingdom.

BACKGROUND: In the last decade, numerous studies have demonstrated concern about the presence of hydrosalpinx and its management in patients undergoing IVF. We evaluated the current management of hydrosalpinx prior to IVF treatment in the UK. METHODS: A total of 117 postal survey, anonymous, sealed questionnaires were sent to all IVF centres in the UK, to determine the policy for the management of hydrosalpinx in infertile women prior to IVF treatment. RESULTS: There were 88 (75%) responders, of which 80 (91%) indicated that they discussed the effect of hydrosalpinx on IVF outcome. Ten (12%) units did not recommend treatment of hydrosalpinx prior to IVF treatment, while 30 (36%), 27 (33%) and 16 (19%) recommended treatment weakly, strongly and very strongly respectively. The treatment options offered by clinicians were laparoscopic salpingectomy (75%), open salpingectomy (45%), salpingostomy (40%), proximal tubal occlusion (34%), transvaginal songraphic (TVS) aspiration during oocyte collection (23%) and TVS aspiration before oocyte collection (10%). The frequency of use varied from one option of treatment to another. Only 28% of the responders had a protocol or guidelines for the management of hydrosalpinx. CONCLUSIONS: More attention should be given to patients with hydrosalpinx prior to IVF treatment and patients should be counselled about the negative effect of hydrosalpinx on IVF outcome. There is a wide variation in the management of hydrosalpinx prior to IVF treatment in the UK and many treatment options may be questionable, as they are not yet based on evidence.

Ambulatory Care Facilities↗
PubMed2004

Human lead exposure in England from approximately 5500 BP to the 16th century AD.

Lead concentration and isotope ratio data are presented for the tooth enamel of 77 individuals buried in England and spanning approximately 5000 years from the Neolithic until the 16th century AD. Whereas other tissues may be affected by diagenesis in the burial environment, the Pb concentration of tooth enamel is directly related to childhood exposure. This record is preserved post-mortem and over archaeological time. Tooth enamel Pb concentrations in the prehistoric period appear to be variable within the range 0.04 to approximately 0.4 ppm, with occasional higher levels. The Romano-British and medieval periods show a marked increase in Pb exposures with enamel concentrations reaching up to approximately 40 ppm. These exposures would today be associated with industrial pollution. Exposures appear to be highly variable compared with modern people, however, with many medieval individuals having very low enamel Pb concentrations comparable with prehistoric people. Lead isotope data refine this picture. We distinguish between the diverse isotopic ratios we believe to be characteristic of 'natural' exposure to Pb-from geological sources via the diet-and the much narrower isotopic range characteristic of exposure to technological Pb from ore sources. Taken together the data suggest that the maximum concentrations associated with 'non-technological' exposure at any period are approximately 0.5-1.0 ppm, similar to that reported for modern people in England.

Adult↗