Developing environment-specific water quality guidelines for suspended particulate matter

It is generally well recognised that suspended particulate matter (SPM), from nano-scale particles to sand-sized sediments, can cause serious degradation of aquatic ecosystems. However, at present there is a poor understanding of the SPM conditions that water quality managers should aim to achieve in contrasting environments in order to support good ecological status. In this article, we analyse long-term SPM data collected from a wide range of reference-condition temperate environments in the UK (638 stream/river sites comprising 42 different ecosystem-types). One-way analysis of variance reveals that there is a statistically significant difference (p < 0.001) between the background SPM concentrations observed in contrasting ecosystems that are in reference condition (minimal anthropogenic disturbance). One of the 42 ecosystems studied had mean background concentrations of SPM in excess of the current European Union (EU) water quality guideline, despite being in reference condition. The implications of this finding are that the EU's current blanket water quality guideline (25 mg L(-1) for all environments) is inappropriate for this specific ecosystem-type which will be non-compliant with the guideline regardless of the intensity of land-use. The other 41 ecosystems studied had mean concentrations below the current EU water quality guideline. However, this does not necessarily mean that the guideline is appropriate for these ecosystems, as previous research has demonstrated that detrimental impacts can be experienced by some freshwater organisms, of all trophic levels, when exposed to concentrations below 25 mg L(-1). Therefore, it is suggested here that it is likely that some ecosystems, particularly those with mean concentrations in the 0.00-5.99 mg L(-1) range, require much lower guideline values in order to be effectively protected. We propose a model for predicting environment-specific water quality guidelines for SPM. In order to develop this model, the 638 reference condition sites were first classified into one of five mean background SPM ranges (0.00-5.99, 6.00-11.99, 12.00-17.99, 18.00-23.99 and >24.00 mg L(-1)). Stepwise Multiple Discriminant Analysis (MDA) of these ranges showed that a site's SPM range can be predicted as a function of: mean annual air temperature, mean annual precipitation, mean altitude of upstream catchment, distance from source, slope to source, channel width and depth, the percentage of catchment area comprised of clay, chalk, and hard rock solid geology, and the percentage of the catchment area comprised of blown sand as the surface (drift) material. The MDA technique, with cross-validation (Wilks-Lambda 0.358, p 0.000), can predict the correct or the next closest SPM range of a site in 90% of cases. This technique can also predict SPM range membership in a probabilistic manner, allowing for an estimate of uncertainty to be made in the allocation of a site to an environment-specific SPM range.

Ethical conflicts and moral distress experienced by paediatric residents during their training

BACKGROUND

Paediatric residents experience numerous ethical conflicts; some of these are experienced by all paediatricians, while others are specifically related to residency training. It has been reported that medical students often feel that they are placed in positions that compromise their own ethical principles. A study in the United States showed that interns frequently face examples of unethical and/or unprofessional conduct among staff.

OBJECTIVES

To identify the ethical conflicts and moral distress experienced by paediatric residents during their training.

METHODOLOGY

Data were collected from four focus groups, which were organized according to the four separate years of residency training. Focus groups consisting of four to 10 participants were led by a research assistant. The focus groups were recorded by an audio device and transcribed verbatim; all data that would identify any of the participants or staff were eliminated. Data analysis involved a modified thematic analysis. The study was approved by the Research Ethics Board at the Hospital for Sick Children in Toronto, Ontario.

RESULTS

While residents occasionally face traditional paediatric ethical issues, such as 'do not resuscitate' orders, more often they experience conflicts because of their inexperience and their place in the hierarchy of the medical care team, particularly when there is disagreement between trainees and senior staff. Their ability to deal and cope with these issues changes as they go through their training. Many residents in the first part of their training were more frustrated and confused with ethical conflicts. In these cases, residents found their best support from their peers and other senior residents. Residents in the later years of training seemed more accustomed to ethical issues. Furthermore, almost all of the residents believed that other members of their health care team have acted in an unethical or unprofessional way.

CONCLUSION

Paediatric residents experience significant ethical conflicts and moral distress. Understanding these ethical issues will help those responsible for postgraduate medical education to review or revise the ethics curriculum in keeping with the current moral distress experienced by residents, and help to mentor and guide trainees.

What are RBC-transfusion-dependence and -independence?

The term RBC-transfusion-dependence is widely-used by hematologists to describe a condition of severe anemia typically arising when erythropoiesis is reduced such that a person continuously requires ≥1 RBC-transfusions over a specified interval. Defining a person as RBC-transfusion-dependent has important implications in diverse hematological disorders especially because it strongly-correlated with decreased survival. Conversely, becoming RBC-transfusion-independent or receiving fewer RBC-transfusions over a specified interval is defined as improvement or response in many disease- and/or therapy-setting. Whether this correlates with improved survival is controversial. We used a structured expert-panel consensus panel process to define RBC-transfusion-dependence and -independence or improvement. We suggest these definitions may prove useful to persons studying or treating these diseases.

Timely Troponins Avoid Admissions: Clinical Assessment of Undifferentiated Chest Pain

Background

Undifferentiated chest pain is a common presentation to acute medicine units. Targeted appropriately timed troponin analysis may reduce unnecessary admissions and relieve bed shortages. We investigated how reliably cardiac chest pain was identified clinically, whether patients had appropriately timed cardiac enzyme analysis, and implications upon rates of admission.

Method

A prospective data collection was completed on 100 consecutive patients admitted with undifferentiated chest pain to an acute receiving unit over 41 days. We excluded patients with acute coronary syndrome or myocardial infarction already confirmed or excluded. Troponin results were retrospectively documented.

Results

Of 100 patients admitted, 67 were thought to have cardiac type chest pain as their only or significant differential diagnosis, and 10 were subsequently confirmed as ACS or MI. Not all patients with cardiac type chest pain were assessed in accordance with SIGN guidelines. 38 patients were admitted overnight solely to await the result of troponin analysis, with a total of 411.5 hours spent waiting at an estimated cost of over £7400.

Conclusion

This study supports the extension of hours of troponin analysis or instant point of care (bedside) cardiac enzyme testing as a cost effective measure, warranting further examination in terms of laboratory service provision.

High pressure study of BaFe2As2--the role of hydrostaticity and uniaxial stress

We investigate the evolution of the electrical resistivity of BaFe(2)As(2) single crystals with pressure. The samples used were from the same batch, grown using a self-flux method, and showed properties that were highly reproducible. Samples were pressurized using three different pressure media: pentane-isopentane (in a piston-cylinder cell), Daphne oil (in an alumina anvil cell) and steatite (in a Bridgman cell). Each pressure medium has its own intrinsic level of hydrostaticity, which dramatically affects the phase diagram. An increasing uniaxial pressure component in this system quickly reduces the spin density wave order and favours the appearance of superconductivity, which is similar to what is seen in SrFe(2)As(2).

Pelvic vein reflux in female patients with varicose veins: comparison of incidence between a specialist private vein clinic and the vascular department of a National Health Service district general hospital

Objectives

Mounting evidence suggests that pelvic vein reflux is an important contributing factor to recurrent varicose veins. We compared the incidence in our specialist private unit (Unit A) with that of a District General Hospital (Unit B).

Methods

Results of all female patient lower limb duplex ultrasound (LLDUS) and transvaginal pelvic ultrasound (TVUS) scans performed over a one-year period were retrospectively reviewed. Patients with refluxing veins emanating from the abdomen or pelvis on LLDUS (non-saphenous reflux) routinely proceeded to TVUS in Unit A.

Results

In Unit A, non-saphenous reflux on LLDUS was present in 90–462 female patients (19.5%). In 81.1% of these, TVUS confirmed reflux in truncal pelvic veins (incidence 15.8%). In Unit B, non-saphenous reflux was present in 60–279 female patients (21.5%).

Conclusion

One in five women presenting with varicose veins have reflux of non-saphenous origin. This is the case in specialist and non-specialist units. One in six has associated pelvic vein reflux.

179. CHARACTERISATION OF THE IN VITRO FUNCTION OF ACTIVIN AC

Activins are members of the TGF-β superfamily that signal via type II and type I receptor subunits and intracellular Smads1. Activin A stimulates FSH release from the pituitary and is also a potent growth and differentiation factor in many physiological systems2. Over-expression of the activin-βC subunit in vitro leads to a reduction in activin A and an increase in activin AC3. Transgenic mice over-expressing activin-βC show decreased circulating activin A, implying that activin AC may also be formed in vivo4. Recently recombinant activin AC has become available, therefore this study examines the in vitro function and mechanism of action of activin AC. Activin AC stimulates FSH release in LβT2 cells and is a negative growth regulator in LNCaP cells, however the potency of activin AC is 8-10 fold less than activin A. Incubation of LNCaP cells with activin receptor antibodies (ALK4, ActRIIA, ActRIIB) abolishes the growth inhibitory effects of activin AC. Activin AC binds to ActRIIB, however a 20-30 fold decrease in both the potency and affinity of activin AC is evident compared to activin A. In addition, activin AC increases Smad-2 phosphorylation. These results indicate activin AC utilises the same receptors and intracellular signalling molecules as activin A. The activin A antagonists, follistatin and activin C4, also antagonise the growth inhibitory effects of activin AC and reduce Smad-2 phosphorylation and Smad-4 expression. This study shows for the first time that the in vitro function of activin AC is similar to activin A, albeit at a lower potency and provides the impetus to determine the physiological role of activin AC in vivo.

Retinol-binding protein 4 and insulin resistance in polycystic ovary syndrome

OBJECTIVE

Polycystic ovary syndrome (PCOS) is an insulin-resistant state with insulin resistance being an established therapeutic target; however, measurement of insulin resistance remains challenging. We aimed to 1) determine serum retinol-binding protein 4 (RBP4) levels (purported to reflect insulin resistance) in women with PCOS and control subjects, 2) examine the relationship of RBP4 to conventional markers of insulin resistance, and 3) examine RBP4 changes with interventions modulating insulin resistance in overweight women with PCOS.

RESEARCH DESIGN AND METHODS

At baseline, 38 overweight women (BMI >27 kg/m(2)) with PCOS and 17 weight-matched control subjects were compared. Women with PCOS were then randomly assigned to 6 months of a higher-dose oral contraceptive pill (OCP) (35 microg ethinyl estradiol/2 mg cyproterone acetate) or metformin (1 g b.i.d.). Outcome measures were insulin resistance (total insulin area under the curve) on an oral glucose tolerance test, RBP4, and metabolic/inflammatory markers.

RESULTS

Overweight women with PCOS were more insulin resistant than control subjects, yet RBP4 levels were not different in women with PCOS versus those in control subjects (35.4 +/- 4.3 vs. 28.9 +/- 3.1 microg/ml, P = 0.36). RBP4 correlated with cholesterol and triglycerides but not with insulin resistance. Metformin improved insulin resistance by 35%, whereas the OCP worsened insulin resistance by 33%. However, RBP4 increased nonsignificantly in both groups (43.7 +/- 6.3 vs. 42.6 +/- 5.5 microg/ml, P = 0.92).

CONCLUSIONS

Overweight women with PCOS were more insulin resistant than control subjects, but this finding was not reflected by RBP4 levels. RBP4 correlated with lipid levels but not with insulin resistance markers. RBP4 levels did not change when insulin resistance was reduced by metformin or increased by the OCP. These data suggest that RBP4 is not a useful marker of insulin resistance in PCOS but may reflect other metabolic features of this condition.

Management of Cannabis and Psychostimulant Use among General Practice Patients

While regular and heavy cannabis and psychostimulant use has been associated with significant health and psychological impairments, the extent to which their use is being identified and managed by general practitioners (GPs) remains unclear. The aim of this study was to explore the management of cannabis- and psychostimulant-related problems in Australian general practice. Data from the Bettering the Evaluation and Care of Health (BEACH) study of general practice between April 2000 and March 2007 were analysed. BEACH is an ongoing national study of general practice activity in Australia. It was estimated that during this period GPs in Australia managed illicit drug use about 55,000 times per year and that cannabis and psychostimulants made up 3.2% and 1.6%, respectively, of all encounters at which the illicit drug was specified. The only difference in patient demographics between patients in the two drug groups was that cannabis users were younger than psychostimulant users. Cannabis users were more likely to be managed concurrently for psychotic symptoms but less likely to be treated with antipsychotics. Conversely, patients using psychostimulants were more likely to be prescribed an antipsychotic and/or an anxiolytic for their presenting drug problem. These results suggest that GPs do manage problematic cannabis and psychostimulant use among their patients, and thus should be supported in carrying out appropriate screening, intervention and referral.