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S Hillier

Publications and source records attributed to S Hillier.

At least 19 recordsLinked to original sources
PubMed2006

Sediment influence on congener-specific PCB bioaccumulation by Mytilus edulis: a case study from an intertidal hot spot, Clyde Estuary, UK.

An intertidal site in the Clyde Estuary, UK, was selected to evaluate the role of sediment geochemistry on the bioaccumulation of polychlorinated biphenyls (PCBs) by mussels (Mytilus edulis). The area had previously been identified as showing anomalously high levels of PCB contamination (over 1,500 microg kg(-1) total PCB in sediment, 22 congeners). Samples of surface sediment and M. edulis were collected from two closely located sites, one within the anomalous area and another representing typical PCB contamination in the estuary. Sediment samples were separated into grain size fractions and analysed for a range of biomarker compounds, PCBs and sediment mineralogy. The anomalous site showed an atypical association of PCBs with sediment properties, despite both locations showing influence of both petrogenic and pyrogenic organic contamination. Interrogation of data using correlation and principal component analysis showed that sediment mineralogy as well as organic matter composition influenced PCB congener distribution. One sediment source was found to control the PCB concentration in mussels at both locations and clay mineralogy appears to control PCB uptake by biota with preference for higher molecular weight congeners. Overall bioavailability is determined by sediment TOC.

Animals↗
PubMed2005

The implications of integrated assessment and modelling studies for the future remediation of chromite ore processing residue disposal sites.

Chromite ore processing residue (COPR) waste from a former chromium chemical works (1830-1968) is still contaminating groundwater in Glasgow, Scotland, with carcinogenic hexavalent chromium, Cr(VI). An integrated analytical, experimental and modelling approach has identified and accounted for mineral phases and processes responsible for the retention and release of Cr(VI) under prevailing field conditions. Both the nature of mineral phase retention and the buffered high pH of the sites, however, militate against direct remediative treatment of the source material, for example by the application of generic methods (e.g. FeSO4) that have been successfully employed elsewhere for the reduction of Cr(VI) to Cr(III) in other matrices. The interception and treatment of groundwater to remove Cr(VI) and the capping of sites to reduce human exposure to airborne Cr(VI)-contaminated dust may well be more realistic and effective, at least in the short to medium term.

Chromium↗
PubMed2005

Role of oxalic acid overexcretion in transformations of toxic metal minerals by Beauveria caledonica.

The fungus Beauveria caledonica was highly tolerant to toxic metals and solubilized cadmium, copper, lead, and zinc minerals, converting them into oxalates. This fungus was found to overexcrete organic acids with strong metal-chelating properties (oxalic and citric acids), suggesting that a ligand-promoted mechanism was the main mechanism of mineral dissolution. Our data also suggested that oxalic acid was the main mineral-transforming agent. Cadmium, copper, and zinc oxalates were precipitated by the fungus in the local environment and also in association with the mycelium. The presence of toxic metal minerals often led to the formation of mycelial cords, and in the presence of copper-containing minerals, these cords exhibited enhanced excretion of oxalic acid, which resulted in considerable encrustation of the cords by copper oxalate hydrate (moolooite). It was found that B. caledonica hyphae and cords were covered by a thick hydrated mucilaginous sheath which provided a microenvironment for chemical reactions, crystal deposition, and growth. Cryo-scanning electron microscopy revealed that mycogenic metal oxalates overgrew parental fungal hyphae, leaving a labyrinth of fungal tunnels within the newly formed mineral matter. X-ray absorption spectroscopy revealed that oxygen ligands played a major role in metal coordination within the fungal biomass during the accumulation of mobilized toxic metals by B. caledonica mycelium; these ligands were carboxylic groups in copper phosphate-containing medium and phosphate groups in pyromorphite-containing medium.

Biodegradation, Environmental↗
PubMed2004

Quantitative assessment of the effects of agricultural practices designed to reduce 137Cs and 90Sr soil-plant transfer in meadows.

Agricultural practices (ploughing and reseeding, addition of lime and fertiliser) were tested as a feasible remediation strategy to reduce 137Cs (RCs) and 90Sr (RSr) soil-plant transfer in natural meadows in areas affected by the Chernobyl fallout. Field experiments were carried out for 2 years at six sites, covering dry and wet meadows. Observed results at field scale showed that ploughing plus reseeding provoked the main reduction in RSr transfer, with no further reduction after liming, while ploughing + reseeding + K fertiliser led to the maximum decrease in RCs transfer at most sites. The direct effects of agricultural practices on the exchange complex and soil solution composition were quantified by subsequent soil analyses. At the doses applied, lime did not affect the Ca + Mg concentrations in the exchange complex and soil solution of the ploughed soils, thus suggesting that the decrease in RSr transfer on treated plots was mainly due to the changes in the plant species after reseeding. With respect to RCs, changes in the K+NH4+ concentrations in the exchange complex and soil solution were consistent with changes in soil-plant transfer. Finally, RSr and RCs soil-plant transfer in ploughed plots was well predicted from soil properties, such as the solid-liquid distribution coefficient, the ionic composition of the soil solution and the exchangeable cations, with Pearson correlation coefficients of 0.98 and 0.86, respectively, between calculated and experimental log transfer factors.

Agriculture↗
PubMed2004

[The respective roles of gonadotrophins on follicular growth and oocyte maturation].

Around 400 follicles sequentially mature and ovulate during an average woman's reproductive lifetime. Follicular growth to the stage of antrum formation is independent of gonadotrophic stimulation and might be dependent of androgen exposure. During the follicular phase, effects of LH must be considered according to the stages of follicular development: in the early follicular phase, LH acts through specific receptors, constitutively present on thecal cells, for stimulating androgen production. Androgens seem to be positively involved in the folliculogenesis in primates. Indeed, a positive correlation has been recently established between androgen receptor expression and follicular cell proliferation. Nevertheless, LH, beyond a certain ceiling level, suppresses granulosa proliferation, and initiates atresia or premature luteinisation. The development-related response to LH shown by the pre-ovulatory follicle raises the possibility that exogenous LH might be used as an adjunct to therapy with exogenous FSH in clinical ovulation induction regimens where the aim is to induce monovulation. Rec LH will allow the opportunity to provide LH support in a flexible and responsive way, with the possibility of fine tuning FSH action on follicular development. Availability of pure, standalone LH will allow a re-evaluation of follicular stimulation based on physiological principles, leading to new treatment protocols.

Androgens↗
PubMed2003

Does induction of plastic change in motor cortex improve leg function after stroke?

Combined peripheral nerve and brain stimulation ("dual stimulation") induces changes in the excitability of normal motor cortex. The authors sought to establish whether dual stimulation would also induce motor cortex plasticity and associated functional improvements in nine stroke patients with chronic stable hemiparesis. Following 4 weeks of daily dual stimulation, improvements were seen in some neurophysiological and functional measures. This technique may offer therapeutic opportunities in some stroke patients.

Adult↗
PubMed2003

Role of quantitative mineralogical analysis in the investigation of sites contaminated by chromite ore processing residue.

A range of techniques, normally associated with mineralogical studies of soils and sediments, has been used to characterise the solid materials found on sites contaminated with chromite ore processing residue (COPR). The results show that a wide range of minerals are present, many of which are found extensively in high-temperature synthetic systems such as cements and clinkers and their low temperature hydration products. Thus, the minerals in COPR can be divided into three main categories: unreacted feedstock ore (chromite); high temperature phases produced during chromium extraction (brownmillerite, periclase and larnite); and finally, minerals formed under ambient weathering conditions on the disposal sites (brucite, calcite, aragonite, ettringite, hydrocalumite, hydrogarnet). Apart from chromite, chromium occurs in brownmillerite, ettringite, hydrocalumite and hydrogarnet. Detailed study of the chemistry and stoichiometry of chromium-bearing phases in conjunction with phase abundance provides a quantitative description of the solid state speciation of Cr(III) and Cr(VI) in and amongst these minerals and in the COPR as a whole. Of the total chromium present in the samples most, approximately 60-70% is present as Cr(III) in chromite, whilst brownmillerite also represents a significant reservoir of Cr(III) which is approximately 15% of the total. The remaining chromium, between 20 and 25%, is present as Cr(VI) and resides mainly in hydrogarnet, and to a slightly lesser extent in hydrocalumite. In the latter, it is present principally in an exchangeable anionic form. Chromium (VI) is also present in ettringite, but quantitatively ettringite is a much less important reservoir of Cr(VI), accounting for approximately 3% of total chromium in one sample, but less than 1% in the other two. This description provides insight into the processes likely to control the retention and release of Cr(VI) from COPR-contaminated sites. Such information is of particular value in chemical modelling of the system, in risk assessment and in the development of methods of informed remediation.

Journal Article↗
PubMed2001

Influences on hospital admission for asthma in south Asian and white adults: qualitative interview study.

OBJECTIVE: To explore reasons for increased risk of hospital admission among south Asian patients with asthma. DESIGN: Qualitative interview study using modified critical incident technique and framework analysis. SETTING: Newham, east London, a deprived area with a large mixed south Asian population. PARTICIPANTS: 58 south Asian and white adults with asthma (49 admitted to hospital with asthma, 9 not admitted); 17 general practitioners; 5 accident and emergency doctors; 2 out of hours general practitioners; 1 asthma specialist nurse. MAIN OUTCOME MEASURES: Patients' and health professionals' views on influences on admission, events leading to admission, general practices' organisation and asthma strategies, doctor-patient relationship, and cultural attitudes to asthma. RESULTS: South Asian and white patients admitted to hospital coped differently with asthma. South Asians described less confidence in controlling their asthma, were unfamiliar with the concept of preventive medication, and often expressed less confidence in their general practitioner. South Asians managed asthma exacerbations with family advocacy, without systematic changes in prophylaxis, and without systemic corticosteroids. Patients describing difficulty accessing primary care during asthma exacerbations were registered with practices with weak strategies for asthma care and were often south Asian. Patients with easy access described care suggesting partnerships with their general practitioner, had better confidence to control asthma, and were registered with practices with well developed asthma strategies that included policies for avoiding hospital admission. CONCLUSIONS: The different ways of coping with asthma exacerbations and accessing care may partly explain the increased risk of hospital admission in south Asian patients. Interventions that increase confidence to control asthma, confidence in the general practitioner, understanding of preventive treatment, and use of systemic corticosteroids in exacerbations may reduce hospital admissions. Development of more sophisticated asthma strategies by practices with better access and partnerships with patients may also achieve this.

Adult↗
PubMed2001

Particulate composition and origin of suspended sediment in the R. Don, Aberdeenshire, UK.

Characterising the nature and origin of suspended particulate and colloidal matter in surface waters is a necessary first step in determining the role of these materials in the transport of pollutants. With this aim in mind, samples of suspended sediment were collected from the R. Don, Scotland, and analysed by a combination of X-ray diffraction (XRD) and vertically attenuated infrared spectroscopy (VATIR). Additionally, the carbon and nitrogen contents of the sediment were measured. Samples were collected at eight sites along the river from the headwaters to the mouth, twice during periods of base flow, and once during a storm. During the base flows, the amount of suspended solids was typically no more than 1-10 mg l(-1), whereas the high flow samples contained up to 150 mg l(-1). XRD showed that the crystalline component of the high flow samples consisted of the clay minerals illite, chlorite, kaolin, hydroxy-interlayered vermiculite, and a 10/14 A regularly interstratified mica/vermiculite. Non-clay components included quartz, feldspars, amphibole and goethite. Kaolin progressively increased in relative abundance downstream. The clay mineralogy of base flow samples was more or less identical to high flow samples but the non-clay components were reduced and, additionally, talc and calcite were present. The identification of many of the crystalline components was confirmed by VATIR, and amorphous silica was identified, particularly in base flow samples. Organic components were identified as wax, protein, and humate/fulvate. Proportionally more protein and wax components relative to silicates occurred in base flow samples, whereas the humate/fulvate component was most clearly identified in samples from the storm. Organic matter contents ranged from approximately 24% during base flow to 13% during the storm, whilst the C/N ratio showed a progressive decrease downstream, irrespective of flow conditions. Both the characteristics of the mineralogy and the organic matter suggested that topsoils were the primary source of the suspended sediment in the R. Don. However, the presence of talc and calcite were believed to fingerprint ground water sources, which together with the in-stream production of diatoms, may have accounted for a significant mass fraction of the suspended particulate matter during base flows.

Calcium Carbonate↗
PubMed2000

Fluoride in drinking water and risk of hip fracture in the UK: a case-control study.

BACKGROUND: Although the benefits of water fluoridation for dental health are widely accepted, concerns remain about possible adverse effects, particularly effects on bone. Several investigators have suggested increased rates of hip fracture in places with high concentrations of fluoride in drinking water, but this finding has not been consistent, possibly because of unrecognised confounding effects. METHODS: We did a case-control study of men and women aged 50 years and older from the English county of Cleveland, and compared patients with hip fracture with community controls. Current addresses were ascertained for all participants; for those who agreed to an interview and who passed a mental test, more detailed information was obtained about lifetime residential history and exposure to other known and suspected risk factors for hip fracture. Exposures to fluoride in water were estimated from the residential histories and from information provided by water suppliers. Analysis was by logistic regression. FINDINGS: 914 cases and 1196 controls were identified, of whom 514 and 527, respectively, were interviewed. Among those interviewed, hip fracture was strongly associated with low body-mass index (p for trend <0.001) and physical inactivity (p for trend <0.001). Estimated average lifetime exposure to fluoride in drinking water ranged from 0.15 to 1.79 ppm. Current residence in Hartlepool was a good indicator for high lifetime exposure to fluoride. After adjustment for potential confounders, the odds ratio associated with an average lifetime exposure to fluoride > or =0.9 ppm was 1.0 [95% CI 0.7-1.5]. INTERPRETATION: There is a low risk of hip fracture for people ingesting fluoride in drinking water at concentrations of about 1 ppm. This low risk should not be a reason for withholding fluoridation of water supplies.

Aged↗
PubMed2000

Invasive disease due to group B Streptococcus in pregnant women and neonates from diverse population groups.

From 1993 through 1996, surveillance for invasive disease due to group B Streptococcus (GBS) in neonates aged <7 days and in peripartum pregnant women was performed in a racially and ethnically diverse cohort in 4 cities in the United States. In a birth population of 157,184, 130 neonatal cases (0.8 per 1000) and 54 maternal cases (0.3 per 1000) were identified. Significant correlates with neonatal disease were black or Hispanic race and a birth weight <2500 g. The attack rate for peripartum maternal infection varied widely by city and may have been influenced by the frequency of administration of intrapartum antibiotics or of evaluating febrile women by performance of blood cultures. Pregnancy loss or GBS disease in the infant occurred in 28% of these maternal cases. Among neonatal and maternal GBS isolates, serotypes Ia (34%-37%) and III (25%-26%) predominated, and type V was frequent (14%-23%). These results provide a description of invasive GBS perinatal infection during the period in which guidelines for prevention were actively disseminated.

Age Distribution↗
PubMed1999

Lead mineral transformation by fungi.

Pyromorphite (Pb5(PO4)3Cl), the most stable lead mineral under a wide range of geochemical conditions [1], can form in urban and industrially contaminated soils [2] [3] [4] [5]. It has been suggested that the low solubility of this mineral could reduce the bioavailability of lead, and several studies have advocated pyromorphite formation as a remediation technique for lead-contaminated land [3] [5] [6], if necessary using addition of phosphate [6]. Many microorganisms can, however, make insoluble soil phosphate bioavailable [7] [8] [9] [10], and the solubilisation of insoluble metal phosphates by free-living and symbiotic fungi has been reported [11] [12] [13] [14] [15]. If pyromorphite can be solubilised by microbial phosphate-solubilising mechanisms, the question arises of what would happen to the released lead. We have now clearly demonstrated that pyromorphite can be solubilised by organic-acid-producing fungi, for example Aspergillus niger, and that plants grown with pyromorphite as sole phosphorus source take up both phosphorus and lead. We have also discovered the production of lead oxalate dihydrate by A. niger during pyromorphite transformation, which is the first recorded biogenic formation of this mineral. These mechanisms of lead solubilisation, or its immobilisation as a novel lead oxalate, have significant implications for metal mobility and transfer to other environmental compartments and organisms. The importance of considering microbial processes when developing remediation techniques for toxic metals in soils is therefore emphasised.

Aspergillus niger↗
PubMed1997

The pathomorphologic changes that accompany the resolution of cervical radiculopathy. A prospective study with repeat magnetic resonance imaging.

STUDY DESIGN: A prospective study with independent clinical and radiologic review. OBJECTIVE: To assess whether regression of cervical intervertebral disc herniations accompanied and correlated with clinical improvement in patients recovering from cervical radiculopathy without undergoing surgical intervention. SUMMARY OF BACKGROUND DATA: The study subjects were 13 consecutive patients, nine men (69%) and four women (31%), presenting with cervical radiculopathy. All patients but one had objective neurologic signs. All patients had large posterolateral cervical intervertebral disc herniations demonstrated by magnetic resonance imaging. METHODS: Pain was controlled by serial periradicular and epidural corticosteroid injections. Patients were finally examined and discharged from care because of sustained pain control at an average of 6 months (range, 2-12 months). They were interviewed subsequently over the telephone by an independent clinician and rescanned at an average of 12 months (range, 4-31 months). The scans were reviewed by an independent radiologist masked to the sequence of the scans. RESULTS: Regression of cervical disc herniations was demonstrated in 12 of the 13 patients. All patients had made a satisfactory clinical recovery, but the one with the herniation that had not regressed suffered from persistent minor symptoms. CONCLUSIONS: Most cervical disc herniations regress with time and without the need for surgical resection. Thus, surgical intervention can be avoided with adequate pain control, allowing the herniation time to regress.

Adrenal Cortex Hormones↗
PubMed1996

Outcome of cervical radiculopathy treated with periradicular/epidural corticosteroid injections: a prospective study with independent clinical review.

This prospective study with independent clinical review was set up to monitor the clinical outcome of patients when using serial periradicular/epidural corticosteroid injection techniques in managing cervical radiculopathy. Over a 10 year period, between 1986 and 1995, a consecutive series of 68 secondary referral patients presenting with cervical radiculopathy were entered into the study. There were 57 men (84%) and 11 women (16%) of average age 47 years (range 31-65 years). The average duration of symptoms prior to presentation was 2 months (range 1-12 months). All patients apart from one had neurological signs. Of the 64 patients (94%) who underwent imaging, relevant pathology thought to correlate with the clinical presentation was demonstrated in all but one patient. Serial periradicular/ epidural corticosteroid injections were used to control pain; an average of 2.5 injections was administered per patient (range 1-6). Patients underwent a final clinical examination when their pain had remained satisfactorily under control for an average of 7 months (range 1-23 months). They subsequently were reassessed, by an independent clinician, at an average of 39 months (range 4-112 months) after initial presentation, via a telephone interview. Despite the fact that all 68 patients were potential surgical candidates, they all made a satisfactory recovery without the need for surgical intervention. Forty-eight patients (76%) did not experience any arm pain, and of the 15 patients (24%) who did, this improved from 10 to an average of 2 (range 1-4) on a 10-point pain scale. Thus, patients with cervical radiculopathy make a satisfactory recovery with serial periradicular/epidural corticosteroid injections without the need for surgical intervention.

Adrenal Cortex Hormones↗
PubMed1996

Bacterial colonization of the vagina during pregnancy in four ethnic groups. Vaginal Infections and Prematurity Study Group.

OBJECTIVE: Our purpose was determine whether there are ethnic differences in vaginal colonization with organisms reputed to be associated with preterm delivery. STUDY DESIGN: In seven urban medical centers in the United States from 1984 to 1989, 13,747 predominantly low-socioeconomic-status women at 23 to 26 weeks' gestation were grouped according to ethnic origin. Each had a vaginal culture for multiple organisms and Gram's stain and pH test to diagnose bacterial vaginosis. Multivariate analyses with adjustment for maternal age, insurance status, marital status, smoking history, education level, age at first sexual intercourse, and number of male partners in the past year were also performed to determine the odds ratio for a black woman versus a white woman having a positive test result. RESULTS: For nearly every organism studied, Asian-Pacific Islander and white women had the lowest percentages of positive test results whereas black women had the highest. When black and white women are compared, black women were more likely to be colonized with Chlamydia trachomatis, 16% versus 5%; Neisseria gonorrhoeae, 2.5% versus 0.4%; Bacteroides sp., 25% versus 14%; bacterial vaginosis, 23% versus 9%; and the four other organisms evaluated. Adjustment for potential confounders including certain health behaviors did not markedly change the risk of a black woman having a positive test result, with the odds ratios for colonization with each organism ranging from 1.8 to 6.4. CONCLUSIONS: Highly significant differences exist in vaginal colonization patterns among women of different ethnic groups, with the highest rates of potentially pathogenic organisms observed in black women and the lowest in Asian-Pacific Islander women. Differences in health behaviors do not explain the variation in colonization rates.

Adult↗