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Biomedical subjects

P Foster

Publications and source records attributed to P Foster.

At least 19 recordsLinked to original sources
PubMed2006

Urrets-Zavalia syndrome as a complication of argon laser peripheral iridoplasty.

OBJECTIVE: To report on 8 patients who developed prolonged mydriasis after argon laser peripheral iridoplasty (ALPI). DESIGN: Retrospective case series. METHODS: A review of the charts of 8 patients with persistent occludable angles after laser iridotomy who developed mydriasis after undergoing ALPI. RESULTS: 12 eyes of 8 patients (mean age 50.2, standard deviation 6.9, range 40-61 years) developed persistent dilatation. 7 of 8 patients had plateau iris syndrome. Only one patient had a decrease in visual acuity. Intraocular pressure increased only in 1 eye and remained stable or decreased in the others. Of the 8 patients, 7 had blurred vision, 2 had photophobia, 4 had glare and 1 had discomfort. The pupillary response to pilocarpine instillation was minimal or absent. Mydriasis eventually resolved in all eyes without treatment. CONCLUSION: ALPI can be complicated by mydriasis unresponsive to pilocarpine. Mydriasis and accompanying symptoms resolved spontaneously within 1 year in most patients.

Adult↗
PubMed2004

Systematic review: is ingestion of paracetamol or non-steroidal anti-inflammatory drugs associated with exacerbations of inflammatory bowel disease?

AIM: To examine the published evidence on the association between paracetamol or non-steroidal anti-inflammatory drugs and relapse in inflammatory bowel disease. METHODS: Medline searches were performed till June 2004 and Embase till April 2003. Abstracts published in Gut and Gastroenterology from 1999 to 2004 were hand-searched. Twenty-nine relevant abstracts and papers were identified. RESULTS: Twenty-two patients with relapse of inflammatory bowel disease following exposure to non-steroidal anti-inflammatory drugs have been described in case-reports. Four patients were re-exposed to non-steroidal anti-inflammatory drugs and relapsed again. Two had relapsed after taking a cyclo-oxygenase 2 inhibitor. One study described increased inflammatory activity and clinical relapse in some patients after challenge with naproxen or nabumetone. Fifteen epidemiological studies were identified. All had small sample sizes and many had methodological problems. Six studies found evidence for an association between non-steroidal anti-inflammatory drug use and relapse of inflammatory bowel disease, but the association was significant in only two. Three studies suggested a relationship between paracetamol use and exacerbations of inflammatory bowel disease. CONCLUSIONS: Non-steroidal anti-inflammatory drugs may precipitate a relapse in some patients with inflammatory bowel disease. This may be an idiosyncratic reaction. The published evidence does not support the view that non-steroidal anti-inflammatory drugs are important in inducing relapse of inflammatory bowel disease. There is weak evidence that paracetamol may be more important.

Acetaminophen↗
PubMed2004

Long-term effects of advice to consume a high-protein, low-fat diet, rather than a conventional weight-loss diet, in obese adults with type 2 diabetes: one-year follow-up of a randomised trial.

AIMS/HYPOTHESIS: This study compared the long-term weight loss and health outcomes at 1-year follow-up, after a 12-week intensive intervention consisting of two low-fat, weight-loss diets, which differed in protein content. METHODS: We randomly assigned 66 obese patients (BMI: 27-40 kg/m2) with type 2 diabetes to either a low-protein (15% protein, 55% carbohydrate) or high-protein diet (30% protein, 40% carbohydrate) for 8 weeks of energy restriction (approximately 6.7 MJ/day) and 4 weeks of energy balance. Subjects were asked to maintain the same dietary pattern for a further 12 months of follow-up. RESULTS: The study was completed by 38 of the subjects, with equal dropouts in each group. At Week 64, weight reductions against baseline were -2.2+/-1.1 kg (low protein) and -3.7+/-1.0 kg (high protein), p<0.01, with no diet effect. Fat mass was not different from baseline in either group. At Week 12, both diets reduced systolic and diastolic blood pressure by 6 and 3 mm Hg respectively, but blood pressure increased more with weight regain during follow-up in the low-protein group (p< or =0.04). At Week 64, both diets significantly increased HDL cholesterol and lowered C-reactive protein concentrations. There was no difference in the urinary urea : creatinine ratio at baseline between the two groups, but this ratio increased at Week 12 (in the high-protein group only, p<0.001, diet effect), remaining stable during follow-up in both diets. CONCLUSIONS/INTERPRETATION: A high-protein weight-reduction diet may in the long term have a more favourable cardiovascular risk profile than a low-protein diet with similar weight reduction in people with type 2 diabetes.

Adipose Tissue↗
PubMed2004

Partitioning of trace metals between soft tissues and shells of Patella aspera.

This paper describes the partitioning of iron, manganese, zinc, copper, cadmium, cobalt, nickel and lead between the soft tissues and the shells of the gastropod mollusc Patella aspera. Specimens of the limpet P. aspera were collected from a clean coastal marine site (CMS) and from an estuarine contaminated site (ECS) on the south coast of Portugal. Fe and Zn concentrations were significantly lower on both populations and less variable in the shells than in the soft tissues. In contrast Mn concentrations were higher in the shells than in the soft tissues at ECS. The partitioning factor (PF), defined as the ratio between the mean metal concentrations in soft tissues and in the shells, was maximum for iron and minimum for manganese. Between the soft tissues and the shells, only manganese at ECS recorded a significant relationship between metal concentrations, suggesting that the mechanism that controls the accumulation of this essential metal in both tissues was different from the others. From the obtained data, in biomonitoring sewage contamination studies, shells of P. aspera can be considered as a good indicator for Mn while the soft tissues for Zn. As copper, cadmium, nickel and cobalt concentrations were much higher in the soft tissues than in the shells (< 0.1 microg g(-1)), this indicates that the shells were not a good indicator for these metals because they do not reflect the environmental bioavailability as do the soft tissues.

Animals↗
PubMed2003

Methods for sampling and analysis of tropospheric ethanol in gaseous and aqueous phases.

In this paper, we report on techniques for sampling and measuring ethanol in both the gas and aqueous phases of the lower troposphere. In the gas phase, the best sampling conditions were ensured by adsorption on Hayesep Q with a Chromosorb W AW coated with LiCl dryer (method 1) or by cryogenic trapping (method 2). An intercomparison campaign showed good agreement between both methods under various conditions. Method 1 (adsorption on Hayesep Q with dryer) is easier to set up and to carry away from the laboratory. Method 2 (cryogenic trapping) requires longer sampling time (up to 60 min while method 1 requires only 10-15 min). Method 1 is adapted to high concentrations of ethanol (>20 ppb) and low relative humidity (<30%). Method 2 gives more accurate results than method 1 for low ethanol concentrations (1-20 ppb). Comparing these results to previous studies, it is clear that sampling with appropriate solid adsorbents or with stainless steel canisters (with appropriate humidified air and short storage time) is adapted to urban or industrial environments where ethanol concentrations are high. Cryogenic sampling must be preferred for remote places where ethanol concentrations are low. Three techniques were tested for sampling ethanol in the liquid phase, namely solid phase microextraction, purge and trap injection, and direct injection. Among those, the latter was chosen for field measurements of ethanol in rain samples at an urban location. These first ever results at an urban location show concentrations ranging from <1 to 5 microM in rains, which agree with the expected range of concentrations. However, the purge and trap method showed detection limits that were 50 times lower and should be preferred for liquid phase ethanol measurements in rural and remote locations. Combining cryogenic trapping for the gas phase (method 2) and direct injection for the liquid phase is convenient and well adapted for a multiphase study of ethanol in the atmosphere, where simultaneous measurements in both phases are needed.

Adsorption↗
PubMed2003

Carcinoid tumour of the terminal ileum simulating Crohn disease.

Carcinoid tumours are often difficult to diagnose because of obscure or non-specific symptoms. Two cases of ileal carcinoid are reported in whom the diagnosis was delayed as the symptoms and small-bowel series were thought to be consistent with Crohn disease. This report emphasizes the difficulties of diagnosing carcinoid by conventional radiological methods. Ileal carcinoid should be considered in the differential diagnosis of Crohn disease, particularly in elderly patients presenting with chronic recurrent symptoms.

Carcinoid Tumor↗
PubMed2002

Increased competition may promote species coexistence.

It is a mainstay of community ecology that local exclusion of species will result if competitive pressures become too large. The pattern of exclusion may be complicated, but the qualitative orthodoxy has changed little since the pioneering work of Lotka, Volterra, and Gause--no two species can occupy the same niche. Stated in a more precise form, the higher the intensity of interspecific competition in an assemblage of species, the fewer the number of species that can coexist in perpetuity. We suggest that this orthodoxy results from "linear" thinking, and that if the classical equations are formulated more realistically with attendant nonlinearities, the orthodoxy breaks down and higher levels of competition may actually increase the likelihood that species will avoid competitive exclusion. Furthermore, this increased probability of coexistence at higher levels of competition is accompanied by characteristic dynamic patterns: (i) at lower levels of competition, after all extinction events have occurred, remaining species follow irregular chaotic patterns; (ii) at higher levels of competition, when most species coexist, all species are entrained in a single large limit cycle; (iii) the transient behavior appears to correspond to a special case of chaos, uniform phase chaotic amplitude.

Ecology↗
PubMed2002

Minor and trace elements in the shell of Patella aspera (Röding 1798).

Specimens of the limpet Patella aspera were collected from a clean, coastal marine site and a contaminated estuary on the south coast of Portugal. The shells were analysed individually for their minor (Mg, Sr) and trace element (Fe, Mn, Zn) content. Mean concentrations of these elements in the shell of P. aspera were 4651, 1318, 35.8, 29.9 and 5.5 microg g(-1), respectively. The elemental concentrations exhibited both a marked intra- and inter-population variability. Despite the variability within individual populations, significant differences in the trace element composition were apparent between the shells taken from the two sites. Small shells (< 2 g) provided the best resolution between sites for both manganese and iron. Differences in zinc were best resolved for larger shells. The shell of P. aspera has an extraordinarily high magnesium concentration, which is insensitive to gross salinity differences, and a trace metal assemblage that can be interpreted in terms of environmental exposure. On these grounds, it is recommended that the shell of P. aspera is a tissue for potential use in environmental trace metal monitoring.

Animals↗
PubMed2001

Seventh Day Syndrome--acute hepatocyte apoptosis associated with a unique syndrome of graft loss following liver transplantation.

AIM: The aim of this study is to describe a unique 7th day syndrome (7DS), quite different from other causes of post-transplantation allograft dysfunction in a group of orthotopic liver transplant (OLT) patients who needed retransplantation. METHODS: A retrospective analysis of 594 consecutive OLT over an 8-year period revealed that 10 patients developed allograft dysfunction approximately 7 days following an initially normal graft function. RESULTS: The features included: (a) severe liver failure; (b) sudden peak of extremely high liver enzymes at approximately day 7; (c) serial liver biopsy findings of central lobular hemorrhage with minimal inflammatory cell infiltrate and (d) an explant with no evidence of vascular thrombosis. The biochemical and morphometric pathological data of these patients were compared with data of patitents who had early acute rejection (AR), hepatic artery thrombosis (HAT), primary nonfunction (PNF), severe sepsis and no dysfunction. Lastly, serial liver core biopsies and explants were tested for evidence of apoptosis, which revealed a significantly higher number of apoptotic hepatocytes in 7DS compared to all control groups. CONCLUSIONS: Seventh Day Syndrome is a distinct entity associated with early graft dysfunction characterized by a marked apoptosis of hepatocytes. Fas receptor activation or other pathways of program cell death may be implicated in occurrence of 7DS.

Acute Disease↗
PubMed2001

Follow-up of patients with unexplained syncope and inducible ventricular tachyarrhythmias: analysis of the AVID registry and an AVID substudy. Antiarrhythmics Versus Implantable Defibrillators.

INTRODUCTION: A prospective registry and substudy were conducted in the Antiarrhythmics Versus Implantable Defibrillators (AVID) Study to clarify the prognosis and recurrent event rate, risk factors, and impact of implantable cardioverter defibrillator (ICD) therapy in patients with unexplained syncope, structural heart disease, and inducible ventricular tachyarrhythmias. METHODS AND RESULTS: Included in the AVID registry were patients from all participating sites who had "out of hospital syncope with structural heart disease and EP-inducible VT/VF with symptoms." In addition, 13 collaborating sites provided more in-depth clinical and electrophysiologic data as part of a formal prospective substudy. Patients in the substudy were followed by local investigators for recurrent arrhythmic events and mortality. Registry patients were tracked for fatal outcomes by the National Death Index. A total of 429 patients with syncope were entered in the AVID registry, of whom 80 participated in the substudy. Of the substudy patients, 21 patients (26%) had inducible polymorphic ventricular tachycardia/ventricular fibrillation (VT/VF), 11 patients (14%) had sustained monomorphic VT <200 beats/min, and 48 patients (60%) had sustained monomorphic VT > or = 200 beats/min. The ICD was used as sole therapy in 75% of the syncope substudy patients (and with antiarrhythmic drug in an additional 9%) and in 59% of the syncope registry patients. Survival rates at 1 and 3 years were 93% and 74% for the substudy patients and 90% and 74% for the registry patients, respectively. Survival of the syncope substudy patients (predominantly treated by ICD) was similar to the VT patients treated by ICD and superior to the VT patients treated by an antiarrhythmic drug (P = 0.05) in the randomized main trial. Mortality events in the substudy were marginally predicted by ejection fraction (P = 0.06) but not by electrophysiologic study-induced arrhythmia. The significant predictor of increased mortality in the registry was age (P = 0.003) and of reduced mortality was treatment with ICD (P = 0.006). CONCLUSION: The results of these analyses support the role of the ICD as primary antiarrhythmic therapy in patients with unexplained syncope, structural heart disease, and inducible VT/VF at electrophysiologic study.

Anti-Arrhythmia Agents↗
PubMed2000

A comparative study of the ability of calcitonin gene-related peptide and adrenomedullin(13 - 52) to modulate microvascular but not thermal hyperalgesia responses.

Calcitonin gene-related peptide (CGRP), a neuropeptide, is a potent vasodilator. Adrenomedullin (ADM) is suggested to be produced by vascular cells in inflamed tissue. ADM shares some structural homology with CGRP. We have compared the ability of CGRP and ADM to modulate microvascular and thermal hyperalgesic responses in rat skin. Vasodilator activity was assessed by laser Doppler flowmetry, inflammatory oedema by the extravascular accumulation of intravenously-injected labelled albumin, and neutrophil accumulation by tissue myeloperoxidase, in dorsal skin. Hyperalgesia was assessed by a thermal hyperalgesimeter in paw skin. ADM (10-300 pmol) was 3 fold less potent than CGRP (3-100 pmol) as a direct vasodilator. CGRP (30 pmol) potentiated oedema formation induced by mediators of increased microvascular permeability, as expected (P<0.01). However, ADM (30-100 pmol) was without a potentiating effect, although ADM (300 pmol) was effective (P<0.01). By comparison ADM (100 pmol) potentiated neutrophil accumulation induced by interleukin-1beta (P<0.05), whereas CGRP (30 pmol) did not. No thermal hyperalgesia was observed to either CGRP or ADM, when given as single or repeated treatments. Thus despite a dilator activity neither CGRP nor ADM appears to mediate hyperalgesic activity in the periphery. However ADM, like CGRP, has the ability to potentiate inflammatory oedema formation and, in addition, ADM can potentiate neutrophil accumulation. ADM may, as suggested for CGRP, act as a modulator of the vascular phases of inflammation. The property of the two compounds of evoking differential microvascular responses and neutrophil accumulation may be due to differing mechanisms of action.

Adrenomedullin↗
PubMed2000

The quantitative measurement of autoantibodies to thyroglobulin and thyroid peroxidase by automated microparticle based immunoassays in Hashimoto's disease, Graves' disease and a follow-up study on postpartum thyroid disease.

The aim of this study was to investigate the association between various autoimmune thyroid diseases and the presence of anti-TPO and anti-Tg antibodies using two novel automated microparticle based immunoassays developed for the AxSYM analyzer. Serum samples from 65 individuals with Hashimoto's Disease, 38 with Graves' Disease and 80 UK blood donors were assayed. In addition, samples were taken from 50 women known to be positive for TPO antibodies, for up to 24 weeks following delivery. Precision for both assays ranges from 5.7-9.1% CV, while analytical sensitivity was determined to be 1.0 IU/ml for Anti-Tg and 0.3 IU/ml for Anti-TPO. The Anti-TPO test showed positive results in 86% of Hashimoto's Disease and 87% of Graves' Disease. The figures obtained for Anti-Tg were 58% and 73% respectively. Specificity was 94% with Anti-TPO and 99% with Anti-Tg. The postpartum women were divided into 2 groups, group A remained symptomless while group B developed thyroid dysfunction. Within the 2 groups, medians calculated at each time point were compared between and within groups using the Mann-Whitney Rank Sum Test or the Kruskal-Wallis One Way ANOVA on Ranks. Anti-TPO baseline levels (week 6) were statistically different between both groups (median 36 vs. 167 IU/ml, p = 0.002). In group A, the median values increased from 36 to 87 IU/ml within the observation period, although the difference was not statistically significant. In group B, antibody titres showed a statistically significant increase from 168 IU/ml (week 6) up to 676 IU/ml after 20 weeks (p < 0.001). Anti-Tg baseline levels were not statistically different between the two groups. In group A, the median values did not change significantly over time (range: 47-86 IU/ml) whereas antibody titres in group B showed a statistically significant increase from 79 IU/ml (week 6) to 276 IU/ml after 24 weeks (p = 0.002). Results obtained indicate that these assays provide useful tools for the quantitative determination of autoantibodies in both primary diagnosis as shown with the Hashimoto's disease and Graves' disease samples and patient follow-up as demonstrated with the postpartum samples. The automation and high precision of the assays make them perfectly suited to routine diagnostic use.

Autoanalysis↗