Evaluation of the utility of the Vigileo FloTrac(™) , LiDCO(™) , USCOM and CardioQ(™) to detect hypovolaemia in conscious volunteers: a proof of concept study

It is important to detect and treat hypovolaemia; however, detection is particularly challenging in the conscious, spontaneously breathing patient. Eight healthy male volunteers were monitored using four minimally invasive monitors: Vigileo FloTrac(™) ; LiDCOrapid(™) ; USCOM 1A; and CardioQ(™) oesophageal Doppler. Monitor output and clinical signs were recorded during incremental venesection of 2.5% estimated blood volume aliquots to a total of 20% blood volume removed. A statistically significant difference from baseline stroke volume was detected after 2.5% blood loss using the LiDCO (p = 0.007), 7.5% blood loss using the USCOM (p = 0.019), and 12.5% blood loss using the CardioQ (p = 0.046) and the FloTrac (p = 0.028). Receiver operator characteristic curves for predicting > 10% blood loss had areas under the curve of 0.68-0.82. The minimally invasive cardiac output devices tested can detect blood loss by a reduction in stroke volume in awake volunteers, and may have a role in guiding fluid replacement in conscious patients with suspected hypovolaemia.

Electrochemical detection of commercial silver nanoparticles: identification, sizing and detection in environmental media

The electrochemistry of silver nanoparticles contained in a consumer product has been studied. The redox properties of silver particles in a commercially available disinfectant cleaning spray were investigated via cyclic voltammetry before particle-impact voltammetry was used to detect single particles in both a typical aqueous electrolyte and authentic seawater media. We show that particle-impact voltammetry is a promising method for the detection of nanoparticles that have leached into the environment from consumer products, which is an important development for the determination of risks associated with the incorporation of nanotechnology into everyday products.

Experimental field estimation of organic nitrogen formation in tree canopies

The content of organic N has been shown in many studies to increase during the passage of rain water through forest canopies. The source of this organic N is unknown, but generally assumed to come from canopy processing of wet or dry-deposited inorganic N. There have been very few experimental studies in the field to address the canopy formation or loss of organic N. We report two studies: a Scots pine canopy exposed to ammonia gas, and a Sitka spruce canopy exposed to ammonium and nitrate as wet deposition. In both cases, organic N deposition in throughfall was increased, but only represented a small fraction (<10%) of the additional inorganic N supplied, suggesting a limited capacity for net organic N production, similar in both conifer canopies under Scottish summertime conditions, of less than 1.6 mmol N m(-2) mth(-1) (equivalent to 3 kg N ha(-1) y(-1)).

Stress responses of Calluna vulgaris to reduced and oxidised N applied under 'real world conditions'

Effects and implications of reduced and oxidised N, applied under 'real world' conditions, since May 2002, are reported for Calluna growing on an ombrotrophic bog. Ammonia has been released from a 10 m line source generating monthly concentrations of 180-6 microg m(-3), while ammonium chloride and sodium nitrate are applied in rainwater at nitrate and ammonium concentrations below 4mM and providing up to 56 kg N ha(-1) year(-1) above a background deposition of 10 kg N ha(-1) year(-1). Ammonia concentrations, >8 microg m(-3) have significantly enhanced foliar N concentrations, increased sensitivity to drought, frost and winter desiccation, spring frost damage and increased the incidence of pathogen outbreaks. The mature Calluna bushes nearest the NH3 source have turned bleached and moribund. By comparison the Calluna receiving reduced and oxidised N in rain has shown no significant visible or stress related effects with no significant increase in N status.

Effects of nitrogen with and without acidified sulphur on an ectomycorrhizal community in a Sitka spruce (Picea sitchensis Bong. Carr) forest

This preliminary study investigated the effects of enhanced nitrogen (NH4NO3 at 48 kg ha(-1) y(-1)), sulphur (Na2SO4 at 50 kg ha(-1) y(-1)), acidified nitrogen and sulphur (H2SO4 + NH4NO3) at pre-stated doses (pH 2.5), and acidified nitrogen and sulphur deposition at double these doses on the ectomycorrhizal community associated with a 13-year-old Sitka spruce (Picea sitchensis) forest. Sulphur deposition had little impact on below ground ectomycorrhizal diversity, but stimulated sporocarp production. Nitrogen inputs increased below ground colonisation compared to acidified nitrogen and sulphur, largely due to an increase in Tylospora fibrillosa colonisation. Sporocarp production and ectomycorrhizal root colonisation by Lactarius rufus were reduced in the nitrogen treated plots. These observations suggest that nitrogen deposition to a young plantation may suppress ectomycorrhizal fungi producing large sporocarps. It is proposed that enhanced nitrogen deposition increases ectomycorrhizal nitrogen assimilation, consuming more carbon and leaving less for extrametrical mycelium and sporocarp development.

Throughfall chemistry and canopy interactions in a Sitka spruce plantation sprayed with six different simulated polluted mist treatments

Throughfall chemistry was studied in a mature Sitka spruce plantation in order to investigate canopy interactions, such as nitrogen absorption, cation leaching, and neutralization of rainfall passing through the canopy. The plantation had been exposed to six different simulated mist treatments including N (NH(4)NO(3)) and S (H(2)SO(4) at pH 2.5) in four replicated blocks since 1996. Throughfall and rainfall were collected from May to September 2000. The results showed that 30-35% of the applied N was retained by the canopy. There were linear relationships between the loss of H(+) and increased K(+), Mg(2+) and Ca(2+) deposition through the canopy. However these increases in K(+), Mg(2+) and Ca(2+) deposition accounted for only about 50% of total neutralization of the acidity. The relationship between the anion deficits in throughfall and the loss of H(+) implied that weak organic acid anions were involved in the neutralization of the acidity in throughfall.

A comparison of monoclonal antibody immobilization of platelet antigen (MAIPA) and immunobead methods for detection of GPIIb/IIIa antiplatelet antibodies in immune thrombocytopenic purpura

In this study we have compared two assays for the detection of autoantibodies GpIIb/IIIa, platelet bound and in serum, in immune thrombocytopenic purpura (ITP). Both assays were found to have a similar sensitivity, but the monoclonal antibody immobilization of platelet antigen (MAIPA) assay was more reproducible than the immunobead assay. The MAIPA and immunobead assay demonstrated an 81% concordance of results for serum antibody detection and a 78% concordance for platelet-associated antibody detection, with an 8-12% incidence of false positive or negative results.

Stem growth reduction in mature Sitka spruce trees exposed to acid mist

An eighteen-year-old clone of Sitka spruce (Picea sitchensis (Bong.) Carr) growing in the field was used to evaluate the whole tree response of 'mature' Sitka spruce to acid mist treatment. The mist, an equimolar mixture of H(2)SO(4) and NH(4)NO(3) at pH 2.5 with or without particles (soda glass ballotini < 20 microm diameter), was applied twice weekly (equivalent to 4 mm precipitation week(-1)) throughout the growing season, May-November 1990-1992. The annual dose of S, N, H applied as mist (at 51, 48 and 3.3 kg ha(-1), respectively) was 2.5 times that measured in the Scottish uplands. Throughout the experiment there was no evidence of visible injury symptoms, yet there was a highly significant reduction (p < 0.02) in the stem-area increment relative to the stem area at the start, measured using vernier dendrometer bands. There was no significant difference between the (acid mist + particle) and the acid mist only treatments. The mean relative stem-area increment over two complete growing seasons (1991-1992) was 65% for control trees, but only 53% for acid-misted trees.

A phase II study of interferon-alpha, interleukin-2 and 5-fluorouracil in advanced renal carcinoma: clinical data and laboratory evidence of protease activation

OBJECTIVE

To confirm the activity and evaluate the toxicity of the combination of subcutaneous interferon-alpha (IFN-alpha) and interleukin-2 (IL-2) with intravenous 5-fluorouracil (5-FU) in patients with advanced and recurrent renal carcinoma and of performance status 0-2. Additionally, to examine protease, complement and neutrophil activation as potential mediators of IL-2 toxicity.

PATIENTS AND METHODS

Fifty-five patients were treated in an 8-week cycle with IFN-alpha (6 MU/m2 on day 1 in weeks 1 and 4 and thrice weekly in weeks 2-3, and 9 MU/m2 thrice weekly in weeks 5-8) IL-2 (20 MU/m2 on days 3-5 in weeks 1 and 4 and 5 MU/m2 thrice weekly in weeks 2-3) and 5-FU (750 mg/m2 on day 1 of weeks 5-8). Patients responding to the first cycle were eligible to continue with further cycles. Toxicity and effects on quality of life were assessed using World Health Organization criteria and the Rotterdam Symptom Checklist and Hospital Anxiety and Depression Scale. Serum levels of C3a, prekallikrein and elastase-alpha 1 proteinase inhibitor (elastase-alpha 1-antitrypsin) were assayed in a subset of patients before, during and after the administration of high-dose IL-2 in week 1.

RESULTS

There were partial remissions in nine patients, with responses in 24% (95% CI 10-38%) of evaluable patients and 16% of all patients. Amongst 25 evaluable patients who had undergone nephrectomy, the response rate was 32% (95% CI 14-50%), whereas there was only one response amongst 22 patients who had not undergone nephrectomy. The median survival for patients with stable disease or partial remission exceeded 22 months. Outcome and survival were related to performance status, number of sites of metastases and nephrectomy. This group of patients was of relatively poor performance status and 18 patients (36%) failed to complete one 8-week treatment cycle. Cardiovascular and renal toxicities were less than those seen with intravenous IL-2 schedules but 44% of patients experienced at least one grade III toxicity and only 14% reported less than two grade II toxicities. Plasma levels of elastase-alpha 1 proteinase inhibitor exceeded the normal range in three of seven patients tested before treatment and increased in all seven patients after treatment with IL-2. The same three patients had raised levels of C3a before treatment and in all patients examined, C3a increased after treatment with IL-2. In contrast, plasma prekallikrein concentrations were below normal before treatment and decreased further afterwards.

CONCLUSIONS

This study confirms the activity of this regimen in patients of good performance status, with limited sites of disease and in those who are fit for nephrectomy, but also showed that treatment was associated with considerable toxicity. The administration of IL-2 is associated with protease activation which may be a suitable target for pharmacological intervention in attempts to ameliorate toxicity.

Particulate and dissolved organic carbon in cloud water in southern Scotland

Total particulate carbon (TPC), which includes both elemental carbon and particulate organic carbon, total suspended particulate matter (TSP) and dissolved organic carbon (DOC) were measured in 53 cloud water samples collected using a passive 'Harp-wire' cloud collector at weekly intervals at a hill-top site in southern Scotland (Dunslair Heights, 602 m above sea level) between December 1990 and April 1992. The concentrations of TPC, TSP and DOC were in the range 0.03-6.9 mg 1(-1) (median 1.05 mg l(-1)), 2.6-51.6 mg l(-1) (median 13.6 mg l(-1)) and 0.-14 mg l(-1) (median 3.6 mg l(-1)), respectively. The concentrations of TPC, TSP and DOC were greatest in winter (December-February), up to 6.9, 42 and 4.6 mg l(-1) respectively in 1990-1991 and up to 6.0, 51 and 14 mg l(-1), respectively, in 1991-1992. Particulate carbon in cloud water samples comprised 1-47% of the TSP. Concentrations of major anions (Cl(-), NO(-)(3), SO(2-)(4)) and pH were measured on the same water samples. Estimates of cloud liquid water content from January to April 1992 were derived from measured wind speeds and volumes of water collected. These estimates suggested that the air contained up to 1.2 microg TPC m(-3), 16 microg TSP m(-3) and 2.3 microg DOC m(-3), which are typical of concentrations to be expected in rural air. There was no correlation between concentrations of DOC in cloud water and either TPC or TSP, indicating that the sources and partitioning of DOC and TPC in the atmosphere are different. The largest concentrations of TPC coincided with the largest concentrations of non-marine sulphate, and although there was a significant linear correlation between the two sets of data, the log-transformed data were not correlated. Concentrations of TPC were significantly correlated with concentrations of other particulate matter (TSP-TPC), suggesting that similar sources and/or partitioning processes were involved in determining concentrations in cloud. Concentrations of DOC in cloud were significantly correlated (p < 0.02) with concentrations of nitrate, suggesting that sources of DOC were related to the emission and chemistry of nitrogen oxides. The very large concentrations of particulate carbon, especially in winter, indicate that carbon-catalysed oxidation of sulphur dioxide by molecular oxygen in cloud water may be a significant pathway when concentrations of hydrogen peroxide are small.

Pollution in the upland environment

As part of a study on the effects of pollutants on forests, a long-term monitoring programme has been operating at two sites (602 and 275 m above sea level (a.s.l.)) in Glentress Forest, south-east Scotland, since June 1987. At these sites, equipment has been recording 20-min data for weather parameters, and cloud and rain event frequency, duration and intensity. The chemical composition of bulk cloud and rainwater has been measured. Cloudwater detection and collection has been made using passive 'Harp wire' gauges (with a cross-sectional area of 0.047 m2) strung with polypropylene filament and having a typical collection efficiency of 29% when compared with independent measurements of windspeed and liquid water content. During 1988, the annual rainfall at the upper site was 1213 mm, occurring over 1776 h. The equivalent cloudwater deposition to a forest with a drag coefficient of 0.06 was estimated to be 375 mm over 1936 h. A 'typical cloud event' lasted 4.5 h and would deposit to forests at a rate of 0.2 mm h(-1). There were significantly higher loadings of suspended particulate material (> 0.2 microm) in cloudwater (mean 18.42, max. 94.5 mg litre(-1)) compared with rainwater (mean 2.6, max. 25.6 mg litre(-1)). There were similar differences in ion concentrations, e.g. for H+ in cloudwater (mean 163, max. 1259 microm) and in rainwater (mean 33, max. 262 microM). It is concluded that cloudwater deposition represents a major pathway for pollutant transfer to the upland environment, especially where the surface vegetation is efficient at capturing cloudwater, i.e. forests. The consequences of this increased pollutant loading to forests and water catchments are yet to be assessed.

Orographic enhancement of snowfall

Field studies have been conducted at a hill site in Scotland to measure the variation with altitude of wet deposition by snowfall. The results showed that, due to wind drift effects, snowflakes were captured very inefficiently by snow collectors. It was therefore not possible to measure an increase in precipitation with altitude. The average concentrations of principal ions dissolved in the snow water were calculated over a two-month period. The results showed that the concentrations increased by factors of between 1.4 and 1.9 with an altitude rise of 400 m. A model of the orographic enhancement of snowfall by the seeder-feeder effect showed that the orographic enhancements of precipitation and pollutant deposition were significantly greater for snowfall than for rainfall. The wind drift of snow crystals and the evaporation of precipitation in dry valley air were important in determining the patterns of deposition.