The relationship of monodentate and bidentate coordinated uranium(VI) sulfate in aqueous solution

The coordination of U(VI) sulfate complexes has been investigated by uranium L III-edge EXAFS and HEXS measurements with the aim to distinguish monodentate and bidentate coordinated sulfate in aqueous solution. UV-vis absorption spectroscopy has been used to differentiate the species and to determine the species distribution as a function of the [SO4 2−]/[UO2 2+] ratio. A monodentate coordination prevails in solutions with [SO4 2−]/[UO2 2+] ratio of 1, where UO2SO4 is the dominant species. Besides the dominating monodentate sulfate a small amount of bidentate sulfate could be observed, indicating that two isomers may exist for UO2SO4. With increasing [SO4 2−]/[UO2 2+] ratio the UO2(SO4)2 2− species becomes the main species. The uranium atom of this species is coordinated by two bidentate sulfate groups.

The detection and management of root resorption lesions using intraoral radiography and cone beam computed tomography - an in vivo investigation

AIM

To compare the accuracy of intraoral periapical radiography with cone beam computed tomography (CBCT) for the detection and management of resorption lesions.

METHODOLOGY

Digital intraoral radiographs and CBCT scans were taken of patients with internal resorption (n = 5), external cervical resorption (n = 5) and no resorption (controls) (n = 5). A 'reference standard' diagnosis and treatment plan was devised for each tooth. Sensitivity, specificity, positive predictive values, negative predictive values and receiver operator characteristic (ROC) curves, as well as the reproducibility of each technique were determined for diagnostic accuracy and treatment option chosen.

RESULTS

The intraoral radiography ROC Az values were 0.780 and 0.830 for diagnostic accuracy of internal and external cervical resorption respectively. The CBCT ROC Az values were 1.000 for both internal and external cervical resorption. There was a significantly higher prevalence (P = 0.028) for the correct treatment option being chosen with CBCT (%) compared with intraoral radiographs (%).

CONCLUSION

CBCT was effective and reliable in detecting the presence of resorption lesions. Although digital intraoral radiography resulted in an acceptable level of accuracy, the superior accuracy of CBCT may result in a review of the radiographic techniques used for assessing the type of resorption lesion present. CBCT's superior diagnostic accuracy also resulted in an increased likelihood of correct management of resorption lesions.

A phase I trial of the HSP90 inhibitor, alvespimycin (17-DMAG) administered weekly, intravenously, to patients with advanced, solid tumours

3534

Background: alvespimycin (17-dimethylaminoethylamino-17-demethoxygeldanamycin, 17-DMAG) inhibits N-terminal ATPase activity of Heat Shock Protein 90 (HSP90). Chaperone interactions are altered such that client proteins are targeted for degradation. The plethora of HSP90 client proteins offers the potential of simultaneous blockade across multiple, oncogenic signalling pathways. Methods: the maximum tolerated dose, at which ≤ 1/6 patients experienced dose limiting toxicity (DLT) was determined by dose-doubling (3+3) design. PK and PD biomarker data were used to define a biologically effective dose (BED). PK (LC/MS/MS) and PD (western blot) assays were validated and compliant with European clinical trial legislation. Cancer Research UK and the NCI were co-sponsors. Results: twenty five patients, median age 58 (range 38–78) years, received 475 infusions at doses between 2.5 and 106 mg/m2. Dose doubling was possible to 80mg/m2 when grade 2 toxicity, including dry eye and blurred vision (2/5 patients) occurred. At 106mg/m2 DLT were observed (grade 3 fatigue, diarrhoea, dehydration and grade 4 hypotension, AST rise) in 2/4 patients, one patient died from cardiac arrest. PK data were as follows; plasma t = 24.6 ± 8.6 hr, Vss 468 ± 383 L (mean ± SD) and clearance 27.7 L/hr (range 8.26 - 153). Maximum plasma concentration increased proportionally with alvespimycin dose, area under the curve was only linear ≤ 80 mg/m2. PD changes (HSP72 induction) in peripheral blood mononuclear cells were detected ≥ 20 mg/m2. HSP90 inhibition (client protein depletion and HSP72 induction) was not readily detected until 106 mg/m2. Tumour samples confirmed HSP90 inhibition 24 hours after 17-DMAG in 1/1 and 2/4 patients given 106 and 80 mg/m2, respectively. Two partial responses one, confirmed, in a patient with hormone refractory prostate cancer and one, investigator assessed, in a patient with melanoma occurred. Both remain on study after 27 and 18 months, respectively. Nine patients (36%) have been on trial ≥16 weeks. Conclusions: The recommended phase II dose of alvespimycin is 80 mg/m2 weekly. PK and PD data support this as a BED.

No significant financial relationships to disclose.

Predicting response to irinotecan/5-fluorouracil (5-FU) chemotherapy for advanced colorectal cancer based on gene expression in primary tumour

e14558

Background: Despite improvements in the treatment of advanced colorectal cancer (CRC), there remains a subset of patients who fail to benefit from chemotherapy. The identification of predictive response markers has been limited by the relative scarcity of metastatic tumour samples for molecular analysis, prompting a need to consider surrogate models for generation of predictive markers. Methods: We performed gene expression profiling of archived formalin fixed paraffin-embedded (FFPE) colorectal primary tumours (dating from 2001–2007) from 40 patients who received irinotecan/5-FU chemotherapy as first line treatment for advanced disease. Patients were classified as responders/non-responders based on radiological response. Gene expression profiling was performed using the Almac Diagnostics Colorectal Disease Specific Array (DSA). Data was analysed using Genespring GX v7.3. Principal Components Analysis (PCA) was used to separate responding and non-responding patients based on the tumour- derived expression data. Predictive classifiers were constructed using several class prediction methods. The performance of the classifiers was assessed by leave-one-out cross-validation. Results: 37 samples passed data QC assessments for inclusion in predictive analysis. PCA using genes passing a t-test and 1.5-fold change filter demonstrated clear separation between responding and non-responding patients. Predictive modelling using the k-nearest neighbour and Support Vector Machine (SVM) algorithms with Fishers exact test as feature selection method each generated seven different predictive classifiers containing 5 to 35 genes; these had an average predictive accuracy of 80%. Predictive modelling of this dataset is ongoing and these encouraging initial results will be extended to a larger patient cohort. Conclusions: DNA microarray profiling has been used to generate gene signatures predictive of response to irinotecan/5-FU therapy in advanced CRC; importantly, these predictive signatures have been generated from FFPE colorectal primary tumour facilitating their independent validation in large patient cohorts and potential clinical implementation in the event of successful validation.

[Table: see text]

Randomized phase II study of decitabine in combination with carboplatin compared with carboplatin alone in patients with recurrent advanced ovarian cancer

5562

Background: Experimental and clinical data (Gifford et al, Clin Cancer Res. 2004) indicate the potential importance of methylation in mediating resistance to carboplatin in ovarian cancer. A previous phase I trial (Appleton et al, J Clin Oncol. 2007) established the feasibility of combining carboplatin with the demethylating agent decitabine on a day 1 + 8 q4 weekly (w) schedule and PD data provided evidence of target cell demethylation. Methods: Patients (pt) with ovarian cancer relapsing 6–12 months following first line treatment were randomised to receive either 6 cycles of carboplatin AUC 6 q4 w (Arm A), or 90 mg/m2 decitabine as a 6 hour infusion on day 1 and carboplatin AUC 6 on day 8 q4 w (Arm B). The primary endpoint was response rate. An interim analysis was planned after 11 patients were enrolled into Arm B. Results: 29 pt were enrolled. After the first 4 pt had been treated (at 90 mg/m2 decitabine) the frequency of dose delays due to neutropenia was considered unacceptable, and therefore the starting dose of decitabine was reduced to 45 mg/m2 for the subsequent 11 pt. 7 out of 14 pt in Arm A completed 6 cycles compared with 0 of 11 in Arm B (at 45 mg/m2 decitabine). Grade 2/3 hypersensitivity reactions were more common in Arm B than Arm A (64% vs. 21%), as were prolonged treatment delays due to neutropenia (36% vs. 10%). At the interim analysis, in the 11 pt treated with 45mg/m2 (Arm B), there were no RECIST responses, while 2 pt had short-lived CA125 responses (59 and 63 days). In contrast 6 of 14 patients in Arm A had RECIST responses consistent with the expected efficacy of carboplatin in this population. Conclusions: The lack of efficacy, as well as the difficulties in treatment delivery in Arm B, led the project team to conclude that the study should be closed. With this dose and schedule, decitabine is ineffective in reversing carboplatin resistance. Further investigations are ongoing to understand (a) the apparent increased incidence of hypersensitivity and (b) the trend towards reduced efficacy in Arm B.

[Table: see text]

Mortality in bronchiectasis: a long-term study assessing the factors influencing survival

There is little literature about the mortality associated with bronchiectasis. The aim of the present study was to investigate factors affecting mortality in patients with bronchiectasis. In total, 91 patients were examined for aetiology, pulmonary function tests, high-resolution computed tomography, sputum microbiology and quality of life scores and were then followed over 13 yrs. Overall, 29.7% of the patients died. On multivariate analysis, age, St George's Respiratory Questionnaire activity score, Pseudomonas aeruginosa infection, total lung capacity (TLC), residual volume/TLC and the transfer factor coefficient were all independently associated with mortality. In patients with moderate to severe bronchiectasis, mortality is associated with a degree of restrictive and obstructive disease, poor gas transfer and chronic pseudomonas infection. These features should guide future research into disease progression, and identify those patients needing intensive treatment.

Arsenic in food and water--a brief history

Arsenic has been used for millenia. Although it has been known for many years that arsenic is soon fatal when ingested at high doses, the effects of low dosages became apparent in the 1980s. The full societal implications are only now becoming clear. It is now known to pose the highest calculated risk of any substance regulated by the US Environmental Protection Agency (EPA); high concentrations have been found in drinking water in many countries. In Bangladesh, in particular, the number of people suffering from over exposure vastly exceeds the number affected by the catastrophic accident at Chernobyl. This article shows the development of the human understanding about chronic arsenic poisoning with Bangladesh as a particular example.

The effects of a twelve-week home walking program on cardiovascular parameters and fatigue perception of individuals with multiple sclerosis: a pilot study

PURPOSE

To investigate the effects of a 12-week home walking program on cardiovascular parameters, fatigue perception, and walking distance in persons with multiple sclerosis (MS).

METHODS

Twelve ambulatory persons with MS, not currently participating in exercise were randomly assigned to control (C) or experimental groups (EX). Pretest data collection included resting HR, BP, fatigue perception (Fatigue Severity Scale), and 6-minute walk test. EX received a home walking program (30 min, 3 x week, x 12 weeks), using a modification of Karvonen's formula to calculate HR range. A HR monitor was used to adjust walking speed. The C group refrained from any regular exercise. Posttest data were collected at week 12 and analyzed using the Mann-Whitney U Test.

RESULTS

No statistically significant differences were noted between groups in any measured parameters; however, walking distance and Physiologic Cost Index did improve in the exercise group.

CONCLUSION

No adverse events or increase in fatigue levels related to the exercise intervention were reported in this study. This home walking program may not be of sufficient intensity to elicit significant cardiovascular changes. Abnormal cardiac responses have been documented in this population, which may have affected the results. Clinicians may need to use alternate measures to assess fitness in this population.

Procalcitonin in stable and unstable patients with bronchiectasis

Presently used markers of infection in bronchiectasis are inadequate to judge stability or make decisions about antibiotic treatment during bacterial exacerbations. Procalcitonin (PCT) is a new marker that has been used in community-acquired pneumonia and promises to allow much more specific and sensitive monitoring of patients with bacterial infections. This is the first study assessing its use in bronchiectasis. Thirty-eight consecutive inpatients and 63 consecutive outpatients were included in the study. All patients had PCT, other inflammatory markers, and a symptom score recorded. Inpatients had these values repeated at day 5 and 10 of their stay, while receiving intravenous antibiotics. Outpatients: PCT levels were generally low in the outpatient group. PCT was significantly correlated to C-reactive protein. Higher levels were associated with increased symptoms (P = 0.09) and an increased likelihood of antibiotic prescription (P = 0.007). Inpatients: As a group, inflammatory markers were significantly higher than in the outpatient group (P = 0.007). There was no correlation between the levels of PCT and the other inflammatory markers. PCT concentrations were generally low (as with other markers), which may reflect mucosal infection. Larger studies are needed, but PCT seems unlikely to be able to guide treatment of an exacerbation in bronchiectasis. PCT may offer more promise as a measure of stability.

Review of wheat improvement for waterlogging tolerance in Australia and India: the importance of anaerobiosis and element toxicities associated with different soils

BACKGROUND AND AIMS

The lack of knowledge about key traits in field environments is a major constraint to germplasm improvement and crop management because waterlogging-prone environments are highly diverse and complex, and the mechanisms of tolerance to waterlogging include a large range of traits. A model is proposed that waterlogging tolerance is a product of tolerance to anaerobiosis and high microelement concentrations. This is further evaluated with the aim of prioritizing traits required for waterlogging tolerance of wheat in the field.

METHODS

Waterlogging tolerance mechanisms of wheat are evaluated in a range of diverse environments through a review of past research in Australia and India; this includes selected soils and plant data, including plant growth under waterlogged and drained conditions in different environments. Measurements focus on changes in redox potential and concentrations of diverse elements in soils and plants during waterlogging.

KEY RESULTS

(a) Waterlogging tolerance of wheat in one location often does not relate to another, and (b) element toxicities are often a major constraint in waterlogged environments. Important element toxicities in different soils during waterlogging include Mn, Fe, Na, Al and B. This is the first time that Al and B toxicities have been indicated for wheat in waterlogged soils in India. These results support and extend the well-known interactions of salinity/Na and waterlogging/hypoxia tolerance.

CONCLUSIONS

Diverse element toxicities (or deficiencies) that are exacerbated during waterlogging are proposed as a major reason why waterlogging tolerance at one site is often not replicated at another. Recommendations for germplasm improvement for waterlogging tolerance include use of inductively coupled plasma analyses of soils and plants.

Comparison of accessory performance using a novel ERCP mechanical simulator

BACKGROUND AND STUDY AIMS

There is a paucity of in vitro methods for evaluating ERCP accessories. We hypothesize that the time taken to perform a simulated single stent or multiple stents placement is different for stenting systems with or without the capability of intraductal ductal release (IDR) of the guide wire.

PATIENTS AND METHODS

We conducted an un-blinded in vitro comparison of ERCP accessories using a mechanical simulator during hands-on ERCP practice workshops. A total of 21 U.S. participants and 20 Chinese participants with various level of ERCP experience took part in the different practice workshops. Accessories with and without the capability of intraductal release of guide wire were compared. Total time required for completing a simulated stenting procedure with single or multiple stents and the respective simulated fluoroscopy time were recorded.

RESULTS

There was no significant difference in the time taken for placement of a single stent using either stenting systems. Stenting system capable of intraductal release of the guide wire required significantly shorter time to complete placement of three stents.

CONCLUSIONS

Using time required to complete a specific task, i. e. biliary stenting, the mechanical simulator permits the performance of different accessories by the same group of operators to be evaluated objectively.

The importance of controlling carbon not emissions or mpg*

In management of carbon dioxide concentrations in the atmosphere, the authors argue that it is far superior to control upstream where the carbon leaves the ground in a limited number of places than further downstream as carbon dioxide is released in a myriad of locations. The authors note that none of the proposals being discussed politically assure this, and they control sector by sector, allowing undesirable room for special interests to be excluded from control.

An unsupervised conditional random fields approach for clustering gene expression time series

MOTIVATION

There is a growing interest in extracting statistical patterns from gene expression time-series data, in which a key challenge is the development of stable and accurate probabilistic models. Currently popular models, however, would be computationally prohibitive unless some independence assumptions are made to describe large-scale data. We propose an unsupervised conditional random fields (CRF) model to overcome this problem by progressively infusing information into the labelling process through a small variable voting pool.

RESULTS

An unsupervised CRF model is proposed for efficient analysis of gene expression time series and is successfully applied to gene class discovery and class prediction. The proposed model treats each time series as a random field and assigns an optimal cluster label to each time series, so as to partition the time series into clusters without a priori knowledge about the number of clusters and the initial centroids. Another advantage of the proposed method is the relaxation of independence assumptions.

Partial mixture model for tight clustering of gene expression time-course

Background

Tight clustering arose recently from a desire to obtain tighter and potentially more informative clusters in gene expression studies. Scattered genes with relatively loose correlations should be excluded from the clusters. However, in the literature there is little work dedicated to this area of research. On the other hand, there has been extensive use of maximum likelihood techniques for model parameter estimation. By contrast, the minimum distance estimator has been largely ignored.

Results

In this paper we show the inherent robustness of the minimum distance estimator that makes it a powerful tool for parameter estimation in model-based time-course clustering. To apply minimum distance estimation, a partial mixture model that can naturally incorporate replicate information and allow scattered genes is formulated. We provide experimental results of simulated data fitting, where the minimum distance estimator demonstrates superior performance to the maximum likelihood estimator. Both biological and statistical validations are conducted on a simulated dataset and two real gene expression datasets. Our proposed partial regression clustering algorithm scores top in Gene Ontology driven evaluation, in comparison with four other popular clustering algorithms.

Conclusion

For the first time partial mixture model is successfully extended to time-course data analysis. The robustness of our partial regression clustering algorithm proves the suitability of the combination of both partial mixture model and minimum distance estimator in this field. We show that tight clustering not only is capable to generate more profound understanding of the dataset under study well in accordance to established biological knowledge, but also presents interesting new hypotheses during interpretation of clustering results. In particular, we provide biological evidences that scattered genes can be relevant and are interesting subjects for study, in contrast to prevailing opinion.

Pseudomonas aeruginosa, cyanide accumulation and lung function in CF and non-CF bronchiectasis patients

In patients with cystic fibrosis (CF) and non-CF bronchiectasis, Pseudomonas aeruginosa is the most important respiratory pathogen. It is able to synthesise hydrogen cyanide, a potent inhibitor of cellular respiration. The present study investigated whether cyanide is present in the sputum of CF and non-CF bronchiectasis patients infected with P. aeruginosa, and whether the detection of cyanide affected lung function. Cyanide was measured in sputum using a cyanide ion selective electrode. Cyanide was detected in sputum from 15 out of 25 CF and non-CF bronchiectasis patients with current P. aeruginosa infection; however, it was not detected in any of the 10 patients without this organism. Maximum levels were 130 microM (mean+/-SE 72+/-6.6 microM). Concurrent lung function data were available on all 21 P. aeruginosa-infected CF patients; the group with measurable sputum cyanide (n = 11) was not different from those without (n = 10) on the basis of age or sex. However, those with detectable cyanide had significantly poorer lung function than those without (forced expiratory volume in one second (% predicted) 26.8+/-3.8 versus 46.0+/-6.7%; forced vital capacity (% pred) 44.4+/-4.9 versus 60.1+/-7.7%). Cyanide is detectable in sputum from cystic fibrosis and non-cystic fibrosis bronchiectasis patients infected with Pseudomonas aeruginosa, and is also associated with impaired lung function.

Human leucocyte antigen class II association in idiopathic bronchiectasis, a disease of chronic lung infection, implicates a role for adaptive immunity

The aetiology of idiopathic bronchiectasis, a lung disease where chronic inflammation and bacterial infection leads to progressive lung damage, is unknown. A possible role for natural killer cells has been highlighted previously. However, a role for adaptive immunity is suggested by the presence of CD4 and CD8 T cells in diseased lung tissue. Evidence of a human leucocyte antigen (HLA) class II disease association would further implicate a role for adaptive immunity. To establish if there is any HLA association, we analysed HLA-A, HLA-B, HLA-DQA1, HLA-DQB1 and HLA-DRB1 alleles in patients with idiopathic bronchiectasis and controls. Genomic DNA from 92 adults with idiopathic bronchiectasis and 101 healthy controls was analysed by polymerase chain reaction with sequence-specific primers. We found an increase in the prevalence of HLA-DRB1*01 DQA1*01/DQB1*05 genes in idiopathic bronchiectasis; that is, the HLA-DR1, DQ5 haplotype (odds ratio 2.19, 95% confidence interval 1.15-4.16, P = 0.0152) compared with control subjects. The association with HLA-DR1, DQ5 implicates a role for CD4 T cells restricted by these molecules in susceptibility to the progressive lung damage seen in this disease. This may operate either through influencing susceptibility to specific pathogens or to self-reactivity and requires further investigation.