Site-specific water quality guidelines: 1. Derivation approaches based on physicochemical, ecotoxicological and ecological data

Generic water quality guidelines (WQGs) are developed by countries/regions as broad scale tools to assist with the protection of aquatic ecosystems from the impacts of toxicants. However, since generic WQGs cannot adequately account for the many environmental factors that may affect toxicity at a particular site, site-specific WQGs are often needed, especially for high environmental value ecosystems. The Australian and New Zealand Guidelines for Fresh and Marine Water Quality provide comprehensive guidance on methods for refining or deriving WQGs for site-specific purposes. This paper describes three such methods for deriving site-specific WQGs, namely: (1) using local reference water quality data, (2) using biological effects data from laboratory-based toxicity testing, and (3) using biological effects data from field surveys. Two case studies related to the assessment of impacts arising from mining operations in northern Australia are used to illustrate the application of these methods. Finally, the potential of several emerging methods designed to assess thresholds of ecological change from field data for deriving site-specific WQGs is discussed. Ideally, multiple lines of evidence approaches, integrating both laboratory and field data, are recommended for deriving site-specific WQGs.

Changes in plasma amino acids during conditioning therapy prior to bone marrow transplantation: Their relevance to antioxidant status

Bone marrow transplant (BMT) recipients undergo a bimodal regimen of conditioning therapy, the precise prescription being dependent upon the primary disease of the individual patient. Generally, this treatment consists of chemotherapy and total body irradiation prior to transplantation, although the latter may or may not be included in the regimen. We have investigated amino acid metabolism and oxidant status in in a small series of BMT recipients before and after conditioning therapy.Plasma amino acids were measured by HPLC on 10 BMT recipients prior to commencing conditioning therapy, and again one week later before transplantation. In addition some general nutritional parameters and antioxidant components were measured. A marked decrease in the plasma concentration of a number of amino acids, especially those concerned with antioxidants, was observed over the 7 days of conditioning therapy.There is also a significant reduction in antioxidant capability, as reflected by measurements of glutathione and erythrocyte glutathione peroxidase (GSHPx), which may have an influence upon post-transplant recovery and graft function. Such a reduction in antioxidant concentrations may also have an influence upon the erythrocyte and platelet support required post-grafting.The data presented in this paper adds to the evidence for the conditional essentiality of some amino acids such as taurine and glutamine, and may support the case for specific antioxidant intervention treatment prior to, and/or after conditioning therapy together with monitoring antioxidant status during the post-grafting period.

Multispecies coexistence of trees in tropical forests: spatial signals of topographic niche differentiation increase with environmental heterogeneity

Neutral and niche theories give contrasting explanations for the maintenance of tropical tree species diversity. Both have some empirical support, but methods to disentangle their effects have not yet been developed. We applied a statistical measure of spatial structure to data from 14 large tropical forest plots to test a prediction of niche theory that is incompatible with neutral theory: that species in heterogeneous environments should separate out in space according to their niche preferences. We chose plots across a range of topographic heterogeneity, and tested whether pairwise spatial associations among species were more variable in more heterogeneous sites. We found strong support for this prediction, based on a strong positive relationship between variance in the spatial structure of species pairs and topographic heterogeneity across sites. We interpret this pattern as evidence of pervasive niche differentiation, which increases in importance with increasing environmental heterogeneity.

Oral choline supplementation for postoperative pain

BACKGROUND

Activation of nicotinic receptors with nicotine has been shown to reduce post-surgical pain in clinical and preclinical studies. Choline is a selective agonist at α7-type nicotinic receptors that does not have addictive or sympathetic activating properties. It is anti-nociceptive in animal studies. We conducted a double-blind randomized trial of oral choline supplementation with lecithin to aid in the treatment of pain after gynaecological surgery.

METHODS

Sixty women having open gynaecological surgery were randomly assigned to receive 20 g of lecithin before surgery or placebo. Plasma choline concentration and tumour necrosis factor (TNF) were measured. Pain report was the primary outcome measure.

RESULTS

We achieved a small but statistically significant increase in choline after surgery with oral supplementation. Plasma TNF was not decreased and pain report was not different between groups at rest or with movement. There were no adverse effects of treatment.

CONCLUSIONS

Oral supplementation with lecithin during the perioperative period resulted in very slow absorption and thus only a small increase in plasma choline was achieved. This concentration was inadequate to reduce TNF as has been shown in other studies. The absence of an anti-inflammatory effect was likely related to our failure to demonstrate efficacy in pain reduction.

Video-assisted structured teaching to improve aseptic technique during neuraxial block

BACKGROUND

Teaching epidural catheter insertion tends to focus on developing manual dexterity rather than improving aseptic technique which usually remains poor despite increasing experience. The aim of this study was to compare epidural aseptic technique performance, by novice operators after a targeted teaching intervention, with operators taught aseptic technique before the intervention was initiated.

METHODS

Starting July 2008, two groups of second-year anaesthesia residents (pre- and post-teaching intervention) performing their 4-month obstetric anaesthesia rotation in a university affiliated centre were videotaped three to four times while performing epidural procedures. Trained blinded independent examiners reviewed the procedures. The primary outcome was a comparison of aseptic technique performance scores (0-30 points) graded on a scale task-specific checklist.

RESULTS

A total of 86 sessions by 29 residents were included in the study analysis. The intraclass correlation coefficient for inter-rater reliability for the aseptic technique was 0.90. The median aseptic technique scores for the rotation period were significantly higher in the post-intervention group [27.58, inter-quartile range (IQR) 22.33-29.50 vs 16.56, IQR 13.33-22.00]. Similar results were demonstrated when scores were analysed for low, moderate, and high levels of experience throughout the rotation.

CONCLUSIONS

Procedure-specific aseptic technique teaching, aided by video assessment and video demonstration, helped significantly improve aseptic practice by novice trainees. Future studies should consider looking at retention over longer periods of time in more senior residents.

Abstract P6-07-10: Luminal A vs. Basal-like Breast Cancer: time dependent changes in the risk of relapse in the absence of treatment

Background: Numerous retrospective analyses of prospective randomized clinical trials of patients treated with adjuvant tamoxifen and chemotherapy have demonstrated that the breast cancer intrinsic subtype Luminal A tumors generally have favorable early initial outcomes, while basal-like tumors are associated with a marked risk of early relapse. To determine the extended natural history of the intrinsic subtypes across two decades of follow up the PAM50 “non-commercial open source bioinformatics” qPCR assay was conducted on node negative tumors accrued through the Cooperative Breast Cancer Tissue Registry (CBCTR) from patients who did not receive systemic therapy.

Methods: Intrinsic subtype calls were obtained from 331 CBCTR cases treated with local interventions only. Tumors were classified into Luminal A (LumA), Luminal B (LumB), HER2-enriched (HER2-E) and Basal-like (BLBC), and correlated relapse-free (RFS). Patient survival and hazard rate were estimated using Kaplan-Meier plots and log-rank test. Multivariable Cox regression analyses were used to determine the significance of the intrinsic subtypes, adjusted with standard clinicopathological variables including tumor size, age at diagnosis, grade, radiation therapy treatment, centralized reviewed estrogen receptor, progesterone receptor and human epidermal growth factor 2 status measured by immunohistochemistry. Patients were diagnosed from 1978 to 1992, with a mean follow-up time of 13 years (range 0.5–31).

Results: Of the 331 tumors tested, 51% of cases were classified as LumA, 18% as LumB, 11% as HER2-E and 20% as BLBC. Although LumA was associated with the best outcome for the first 10-year of follow-up, the final number of RFS events were eventually comparable with those observed for BLBC with prolonged follow up (Table 1). In the multivariable Cox model, only BLBC tumors were associated with worse prognosis than LumA with borderline significance (Hazard ratio: 2.0 (95% CI 0.9–5), p = 0.07). BLBC had the highest hazard rates for the first 5 years (7% at first year to 5% at 5 yr), consistent with previous observations. Interestingly, in the absence of treatment, the slow growing LumA subtype had a gradual increase of hazard for an RFS event from 3% at 5 yrs to 4% at 10 yrs to 7% at 20 yrs. The hazard rates of LumA cross with those of BLBC at 10 years.

Abstract P3-06-09: Test of association between Ki67 index of early breast cancer and local relapse after adjuvant hypofractionated radiotherapy

Introduction: There is a strong inverse association between the proliferation indices of early- and late-responding normal tissues and their sensitivity to radiotherapy fraction size. The aim of this study is to test for association between Ki67 index and the fractionation sensitivity of breast cancer. The hypothesis is that tumours with high Ki67 indices are relatively insensitive to fraction size and be over-represented in tumours relapsing after hypofractionated, radiotherapy.

Methods: Between 1986 and 2003, the START pilot and START A trials tested 2 test dose levels of a 13-fraction regimen (3.0 or 3.3 Gy & 3.0 or 3.2 Gy fractions, respectively) in 5 weeks against 25 fractions of 2.0 Gy following primary surgery for early breast cancer. Primary tumour blocks of patients with local tumour relapse were collected for immunohistochemistry (IHC) for Ki67 (manual counting in whole sections), HER2, ER & PR (Allred quick scores in tissue sections). Ki67 was assumed to be log normally distributed with a standard deviation of 0.5–0.9. Assuming evaluable blocks for 240 patients, a standardised detectable difference of 0.45 (90%+ power, 5% significance level) corresponded to a detectable difference in geometric means of 5–10%.

Results: From a total of 3646 patients entered into the START pilot and START A trials, 261 local tumour relapses were recorded at a median follow up of 8.4 years (range 0.9–17.5) and 7.2 (range 0.7–11.9) years respectively. Blocks from 213 patients were recovered, of which 176 were evaluable by IHC. There was no significant difference in proliferation between tumours relapsing after conventional and hypofractionated radiotherapy, with mean Ki67 scores of 7.63 (95%CI: 5.06–11.5) and 5.33 (95CI%: 3.86–7.35), respectively. Mean Ki67 scores in 48 primary triple negative tumours (TNT) that relapsed locally were 15.74 (95%CI: 8.53–29.06) after conventional and 7.52 (95%CI: 3.51–16.1) after hypofractionated radiotherapy, but TNT were equally represented (28%) in both groups.

Conclusion: An association between proliferative indices and fractionation sensitivity in breast tumours has not been demonstrated. If confirmed, it suggests that genetic and epigenetic features unrelated to proliferation are sources of inter-tumour variation in fractionation sensitivity.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-06-09.