Risk calculator to predict 30-day mortality in left-sided infective endocarditis. The EURO-ENDO score

Background/Introduction

Infective endocarditis (IE) is associated with high in-hospital mortality, despite improvements in therapeutic strategies. Nonetheless, there is no prospective risk model to estimate IE mortality.

Purpose

We sought to develop and validate a calculator to predict 30-day mortality risk regarding to perform surgery or medical treatment alone in left-sided IE.

Methods

This is a prospective, multicenter registry that included patients between January 2016 and March 2018 with a diagnosis of IE based on ESC 2015 diagnostic criteria. Patients with possible or definite left-sided IE were included in the analyses. Clinical, biological, microbiological and imaging data were collected. The primary end point was 30-day mortality in patients with left-sided IE. The risk calculator was based on multivariable Cox regression models. The accuracy of the logistic regression models was assessed by discrimination and calibration using C-statistic and Hosmer-Lemeshow test.

Results

Among 3116 patients included, 2171 patients presented left-sided IE and 257 patients (11.8%) died during the first 30 days of IE diagnosis. After multivariable Logistic regression analysis, eleven variables were associated with 30-days mortality and were included in the calculator: previous cardiac surgery, previous stroke/TIA, creatinine >2 mg/dL, S. aureus infection, embolic events on admission, heart failure or cardiogenic shock, vegetation size >14 mm, presence of abscess, severe regurgitation, double left-sided IE and no left valve surgery. There was an excellent correlation between the predicted 30-days mortality in both models with or without performing left valve surgery (area under the receiver operator curve: 0.798 and 0.758, respectively). Moreover, calibration by Hosmer-Lemeshow were 0.085 and 0.09, respectively).

Conclusion(s)

Our risk score in patients with left-sided IE provides an accurate individualized estimation of 30-day mortality according to perform or not perform left-valve surgery. It allows medical professionals to determine whether submitting patients to surgery or not, and thus improve their prognosis.

Funding Acknowledgement

Type of funding sources: None.

Predictors of mortality in patients with left-side infective endocarditis, the ESC-EORP EURO-ENDO registry

Background/Introduction

Infective endocarditis (IE) is associated with high in-hospital mortality, ranging from 16% to 25%, despite improvement in diagnostic and therapeutic strategies, mainly due to complications and heterogeneity of the disease. Baseline risk stratification is essential, in order to focus an aggressive management toward high-risk patients.

Purpose

We sought to assess the association between surgery and 30-day mortality rate as related to vegetation size.

Methods

The ESC-EORP EURO-ENDO registry is a prospective multicentre observational study of patients presenting with definite or possible IE in Europe and ESC-affiliated/non-affiliated countries. Patients were included from January 2016 to 31 March 2018 in 156 centers from 40 countries. Clinical data, blood test analysis and multi-modality imaging tests (echocardiography, computed tomography, PET-CT, magnetic resonance) were collected. Primary endpoint was 30-day mortality. Multivariable logistic regression analysis was performed to assess variables associated with 30-day mortality. Besides, univariable analysis was performed to assess best vegetation size cut-off related to 30-day mortality.

Results

Among 2171 patients with left-side IE, 257 patients (11.8%) died during the first 30 days of IE diagnosis. Patient characteristics and univariable analysis are summarized in TABLE 1. Cut-off value for best vegetation size related to 30-day mortality was vegetation length >14mm, with a HR =2.00 (95% CI 1.59–2.51, p<0.0001) and a Harrell's Concordance of 0.58. After multivariable logistic regression analysis, factors associated with 30-day mortality risk were: vegetation size >14mm (OR =2.68, 95% CI [1.96–3.67], p<0.0001), previous stroke or transient ischemic attack (TIA) (OR =1.60, 95% CI [1.07–2.40], p=0.0235), creatinine >2mg/dL (OR =2.45, 95% CI [1.73–3.47], p<0.0001), presence of embolic events (OR =2.64, 95% CI [1.86–3.74], p<0.0001), hemorrhagic stroke (OR=3.71, 95% CI [1.80–7.64], p=0.0004), presence of heart failure or cardiogenic shock (OR =3.50, 95% CI [2.57–4.77], p<0.0001) and no cardiac surgery during the event (OR =4.07, 95% CI [2.93–5.67], p<0.0001). The C-statistic of the logistic model to predict 30-day mortality was 0.795.

Conclusion

Left-side infective endocarditis had a high 30-day mortality rate (11.8%). Presence of a large vegetation size (>14mm), embolic events, hemorrhagic stroke, renal failure, presence of heart failure or cardiogenic shock were associated with an increase in 30-day mortality. Performing cardiac surgery had a protective effect.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): ESC-EORP EURO-ENDO project from the ESC society

Predictors of mortality in patients with right-side and cardiac device-related infective endocarditis, the esc-eorp euro-endo registry

Background/Introduction

Mortality in right-sided infective endocarditis (RSIE) and cardiac device-related IE (CDRIE) rates have increased mainly due derived complications and heterogeneity of the disease. A better understanding of associated risk factors to mortality in these entities are required in order to develop an efficient therapy.

Purpose

The aim of this study was to assess 30-day mortality rate and variables associated in RSIE and CDRIE.

Methods

The ESC-EORP EURO-ENDO registry is a prospective multicenter observational study of patients presenting with definite or possible IE in Europe and ESC-affiliated/non-affiliated countries. Patients were included from January 2016 to 31 March 2018 in 156 centers from 40 countries. Clinical data, blood test analysis and multi-modality imaging tests (echocardiography, computed tomography, PET-CT, magnetic resonance) were collected. Primary endpoint was 30-day mortality. Univariable analysis was performed to assess variables associated with 30-day mortality.

Results

Among 269 patients with RSIE, 24 patients (9.8%) died during the first 30-day of IE diagnosis. Cut-off value for best vegetation size related to 30-day mortality was vegetation length >19mm, with a HR = 2.88 (95% CI 1.26–6.58, p=0.01) and a Harrell's Concordance of 0.632. Factors associated with 30-days mortality by univariable analysis were: vegetation size >19mm (OR = 2.99, 95% CI [1.31–6.84], p=0.009), previous stroke or transient ischemic attack (OR = 5.10, 95% CI [1.19–21.88], p=0.029), HIV infection (OR = 3.52, 95% CI [1.03–12.10], p=0.046), chronic renal failure (OR = 2.66, 95% CI [1.06–6.71], p=0.038), congestive heart failure at admission (OR = 2.34, 95% CI [1.00–5.47], p=0.050) and severe regurgitation (OR = 3.77, 95% CI [1.56–9.09], p=0.003).

On the other side, among the 227 patients with CDRIE, 24 patients (8.8%) died during the first 30-day of IE diagnosis. Factors associated with an increase in 30-day mortality by univariate analysis were: age per 10 years (OR = 1.49, 95% CI [1.02–2.18], p=0.039), heart failure history (OR = 3.88, 95% CI [1.39–10.80], p=0.009), congestive heart failure on admission (OR = 5.80, 95% CI [2.31–14.55], p<0.001) and cardiogenic shock on admission (OR = 13.37, 95% CI [3.75–47.64], p<0.001). An increase in left ventricular ejection fraction (LVEF) per 10% was a protective factor (OR = 0.66, 95% CI [0.49–0.90], p=0.008).

Conclusions

Patients with RSIE and CDRIE had a not negligible 30-day mortality rate (9.8% and 8.8%, respectively). Factors associated with RSIE and CDRIE mortality are different; while in the right side location, the mortality was related with vegetation size and comorbidities, in the case of CDRIE, the mortality was mainly associated to the presence of heart failure.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Euro-Endo registry by European Society of Cardiology

HBO1 is required for the maintenance of leukaemia stem cells

Acute myeloid leukaemia (AML) is a heterogeneous disease characterized by transcriptional dysregulation that results in a block in differentiation and increased malignant self-renewal. Various epigenetic therapies aimed at reversing these hallmarks of AML have progressed into clinical trials, but most show only modest efficacy owing to an inability to effectively eradicate leukaemia stem cells (LSCs)1. Here, to specifically identify novel dependencies in LSCs, we screened a bespoke library of small hairpin RNAs that target chromatin regulators in a unique ex vivo mouse model of LSCs. We identify the MYST acetyltransferase HBO1 (also known as KAT7 or MYST2) and several known members of the HBO1 protein complex as critical regulators of LSC maintenance. Using CRISPR domain screening and quantitative mass spectrometry, we identified the histone acetyltransferase domain of HBO1 as being essential in the acetylation of histone H3 at K14. H3 acetylated at K14 (H3K14ac) facilitates the processivity of RNA polymerase II to maintain the high expression of key genes (including Hoxa9 and Hoxa10) that help to sustain the functional properties of LSCs. To leverage this dependency therapeutically, we developed a highly potent small-molecule inhibitor of HBO1 and demonstrate its mode of activity as a competitive analogue of acetyl-CoA. Inhibition of HBO1 phenocopied our genetic data and showed efficacy in a broad range of human cell lines and primary AML cells from patients. These biological, structural and chemical insights into a therapeutic target in AML will enable the clinical translation of these findings.

Questionnaire survey on medical futility and termination of resuscitation in cardiac arrest patients among emergency physicians in Hong Kong

INTRODUCTION

The perceptions of medical futility and decisions about termination of resuscitation (TOR) for out-of-hospital cardiac arrest (OHCA) are highly heterogeneous and dependent on the practice of the attending emergency physicians. The objective of this study was to report and investigate the knowledge, attitudes, and practices regarding medical futility and TOR during management of OHCA in Hong Kong.

METHODS

A cross-sectional survey was conducted among emergency medicine physicians in Hong Kong. The questionnaire assessed participants' background, knowledge, attitudes, and behaviours concerning medical futility and TOR in management of OHCA. Composite scores were calculated to reflect knowledge, attitudes, and practices of OHCA treatment. Subgroup analysis and multiple regression analysis were used to explore the relationship between participants' background, knowledge, attitudes, and behaviours.

RESULTS

The response rate to this survey was 57% (140/247). Independent predictors of less aggressive resuscitation in OHCA patients included status as a Fellow of the Hong Kong College of Emergency Medicine (β= -0.314, P=0.028) and being an Advanced Cardiac Life Support instructor (β= -0.217, P=0.032). There was no difference in aggressiveness of resuscitation in terms of years of clinical experience (β=0.015, P=0.921), knowledge of TOR (β=0.057, P=0.509), or attitudes about TOR (β= -0.103, P=0.214). The correlation between knowledge and attitudes was low (Spearman's coefficient=0.02, P=0.795).

CONCLUSION

Clinical practice and behaviour of TOR was not demonstrated to have associations with knowledge or attitude. Status as a Fellow of the Hong Kong College of Emergency Medicine or Advanced Cardiac Life Support instructor were the only two parameters identified that had significant relationships with earlier TOR in medically futile patients with OHCA.

Influence of Urban Green Space and Facility Accessibility on Exercise and Healthy Diet in Hong Kong

Background A cross-sectional study using a convenience sampling method was conducted to understand how green space and accessibility of common public open spaces in compact urban areas affect physical activity and healthy diets of residents. Methods A total of 554 residents completed a structured questionnaire on quality of life, physical activity level and healthy eating practice. Particularly, categories of physical activity and durations were obtained by using the short form Chinese International Physical Activity Questionnaire (IPAQ-C), then the Metabolic Equivalent of Task (MET)-minutes/week was calculated using the formulae (walking minutes × walking days × 3.3) + (moderate-intensity activity minutes × moderate days × 4.0) + (vigorous-intensity activity minutes × vigorous-intensity days × 8.0). The percentage of green space was calculated based on a spatial buffer with a 500 m radius from participants' geocoded addresses using a SPOT ('Satellite Pour l'Observation de la Terre' in French) satellite image-derived vegetation dataset. Parks, promenade and sports facilities were examples of open spaces. Results The sampled population who lived with green space averaged 10.11% ± 7.95% (ranged 1.56-32.90%), with the majority (90%) performing physical activities at medium and high levels. MET-minutes/week was significantly associated (Pearson r = 0.092; p < 0.05) with the green space percentage. Relatively active residents commonly used open spaces within the district for performing exercise, in particular, parks and promenades were mostly used by older residents, while sports facilities by the younger groups at age 25-44 and <25 years. Conclusions Current findings suggested promotion of exercise could be achieved by the design or redesign of built environment to include more parks accessible to the residents with the increase of vegetation.

Observations of tropospheric aerosols and NO2 in Hong Kong over 5years using ground based MAX-DOAS

In this paper, we present long term observations of atmospheric aerosols and nitrogen dioxide (NO₂) in Hong Kong using a Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) instrument. Ground based MAX-DOAS measurements were performed over 5years from December 2010 to November 2015. Vertical distribution profiles of aerosols and NO₂ were derived from MAX-DOAS O₄ and NO₂ observations by applying the optimal estimation method. Retrieved MAX-DOAS measurements of aerosols and NO₂ show good agreement with sun photometer observation of aerosol optical depths (AODs) and long path DOAS measurement of ground level NO₂ mixing ratios. Tropospheric vertical column densities (VCDs) of NO₂ derived from MAX-DOAS measurements are used to validate OMI satellite NO₂ observations. Daily data show reasonably good agreement with each other with Pearson correlation coefficient R=0.7. However, MAX-DOAS NO₂ VCDs are on average higher than OMI observations by a factor of 2. Introducing aerosols in the air mass factor calculation would enhance the OMI VCDs by 7-13%, the remaining discrepancy is mainly due to the differences in spatial coverage between the two instruments. Diurnal variation patterns of aerosols and NO₂ indicated significant contributions from local anthropogenic emissions. Analysis of air mass transport shows that the enhancement of surface aerosols and NO₂ concentrations mainly results from accumulation of local emissions under low wind speed conditions.

Effect of immunosuppressive therapies on survival of systemic lupus erythematosus: a propensity score analysis of a longitudinal cohort

Objectives The aim of this study was to study the relationship between immunosuppressive drug treatment and survival in patients with systemic lupus erythematosus (SLE). Methods Patients who fulfilled four or more American College of Rheumatology criteria for SLE were followed longitudinally. Clinical characteristics, use of immunosuppressive agents and mortality were reviewed. Cox regression was used to study the relationship between immunosuppressive treatment and survival, adjusted for age, sex, vascular risk factors, organ damage, the anti-phospholipid antibodies and a propensity score for the indication of individual immunosuppressive agent derived from separate regression models. Results A total of 803 SLE patients were studied (92% women; age of SLE onset 33.2±14 years; follow-up time 10.8±7.7 years). The frequencies of ever use of immunosuppressive agents were: high-dose prednisolone (≥0.6 mg/kg/day for ≥4 weeks) (85%), azathioprine (63%), cyclophosphamide (25%), mycophenolate mofetil (27%), the calcineurin inhibitors (23%) and hydroxychloroquine (69%). Ninety-seven patients (12%) died and 56 (7%) patients were lost to follow-up. The causes of death were infection (44%), cerebrovascular events (12%), cardiovascular events (10%) and malignancy (8.2%). Cox regression revealed that the ever use of high-dose prednisolone, mycophenolate mofetil, calcineurin inhibitors or cyclophosphamide was not significantly associated with improved survival. However, the ever use of hydroxychloroquine (hazard ratio 0.59 (0.37-0.93); P=0.02) and azathioprine (hazard ratio 0.46 (0.28-0.75); P=0.002) was significantly associated with reduced mortality (41% and 54%, respectively) after adjustment for the propensity score and other confounding factors. A similar beneficial effect of hydroxychloroquine and azathioprine on survival was also observed in patients with lupus nephritis. Conclusions In this longitudinal cohort of Chinese SLE patients, the ever use of hydroxychloroquine and azathioprine was significantly associated with a probability of better survival. Treatment with high-dose prednisolone, cyclophosphamide, mycophenolate mofetil or the calcineurin inhibitors was not associated with long-term survival benefit.

Biomass burning sources and their contributions to the local air quality in Hong Kong

In this paper, we present a quantitative estimation of the impacts of biomass burning emissions from different source regions to the local air quality in Hong Kong in 2014 using global chemistry transport model simulations, sun photometer measurements, satellite observations and local monitoring network data. This study focuses on two major biomass burning pollutants, black carbon aerosols and carbon monoxide (CO). The model simulations of atmospheric black carbon and CO show excellent agreement with sun photometer aerosol optical depth (AOD) measurements, satellite CO columns observations and local monitoring stations data. From the model simulation results, we estimated that biomass burning contributes 12% of total black carbon and 16% of atmospheric CO in Hong Kong on annual average. South East Asia shows the largest influence to the black carbon and CO levels in Hong Kong, accounts for 11% of the total atmospheric black carbon and 8% of CO. Biomass burning in North East Asia and Africa also show significant impacts to Hong Kong. Elevated levels of atmospheric black carbon aerosols and CO were observed during springtime (March and April) which is mainly due to the enhancement of biomass burning contributions. Black carbon and CO originating from biomass burning sources are estimated to contribute 40% of atmospheric black carbon and 28% of CO in Hong Kong during March 2014. An investigation focusing on the biomass burning pollution episode during springtime suggests the intensified biomass burning activities in the Indochinese Peninsula are the major sources of black carbon and CO in Hong Kong during the time.

International experts' practice in the antibiotic therapy of infective endocarditis is not following the guidelines

OBJECTIVE

The management of infective endocarditis (IE) may differ from international guidelines, even in reference centres. This is probably because most recommendations are not based on hard evidence, so the consensus obtained for the guidelines does not represent actual practices. For this reason, we aimed to evaluate this question in the particular field of antibiotic therapy.

METHODS

Thirteen international centres specialized in the management of IE were selected, according to their reputation, clinical results, original research publications and quotations. They were asked to detail their actual practice in terms of IE antibiotic treatment in various bacteriological and clinical situations. They were also asked to declare their IE-related in-hospital mortality for the year 2015.

RESULTS

The global compliance with guidelines concerning antibiotic therapy was 58%, revealing the differences between theoretical 'consensus', local recommendations and actual practice. Some conflicts of interest were also probably expressed. The adherence to guidelines was 100% when the protocol was simple, and decreased with the seriousness of the situation (Staphylococus spp. 54%-62%) or in blood-culture-negative endocarditis (0%-15%) that requires adaptation to clinical and epidemiological data.

CONCLUSION

Worldwide experts in IE management, although the majority of them were involved and co-signed the guidelines, do not follow international consensus guidelines on the particular point of the use of antibiotics.

Update and new approaches in the treatment of Castleman disease

First described 60 years ago, Castleman disease comprises a rare and heterogeneous cluster of disorders, characterized by lymphadenopathy with unique histological features and associated with cytokine-driven constitutional symptoms and biochemical disturbances. Although unicentric Castleman disease is curable with complete surgical excision, its multicentric counterpart is a considerable therapeutic challenge. The recent development of biological agents, particularly monoclonal antibodies to interleukin-6 and its receptor, allow for more targeted disease-specific intervention that promises improved response rates and more durable disease control; however, further work is required to fill knowledge gaps in terms of underlying pathophysiology and to facilitate alternative treatment options for refractory cases.

Outcome Determining Factors for displaced Intra-articular Calcaneal Fractures treated operatively

Introduction: Calcaneal fractures are caused by high energy trauma and mostly are intra-articular fractures. Nondisplaced intra-articular calcaneal fracture (IACF) can be treated non-operatively. However, displaced intra-articular need to be reduced and fixed anatomically to facilitate early ankle rehabilitation and minimize functional impairment. This study was done to find out the outcome of the IACF patients who underwent operative treatment.

Methods: 62 patients with IACF were selected in this study and had been followed up from June 2009 to May 2013. They were placed into two groups; the operative treated and non-operative treated groups. Bilateral ankle lateral view plain radiographs were taken for comparison of the Bohler and Gissane angles. Both groups of patients were assessed by the Maryland Foot Score (MFS) and the SF-36v2 general health survey questionnaire. The ability of the patients to perform activity of daily living (ADL) and /or return to work (RTW) was assessed as well.

Results: The operative treatment group of displaced IACF patients achieved no significant better scores in the mean MFS and SF-36v2 mean scores as compared to non operated cases. There was no difference in RTW between the 2 groups, but earlier ADL was recorded in the operated group. However, this study had found 5 associated factors which causes major effect to the patients’ outcome to treatment.

Conclusions: The patient’s compliance with post-operative rehabilitation regimen were found to be significantly related with the outcomes.

Effect of golimumab and pamidronate on clinical efficacy and MRI inflammation in axial spondyloarthritis: a 48-week open randomized trial

OBJECTIVES

To compare the effect of golimumab (GLM) and pamidronate (PAM) on clinical efficacy and magnetic resonance imaging (MRI) inflammation in axial spondyloarthritis (aSpA).

METHOD

Patients who fulfilled the Assessment of SpondyloArthritis Society (ASAS) criteria for aSpA and had active disease [Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score ≥ 4] were randomized in a 2:1 ratio to receive either GLM (50 mg) or PAM (60 mg) 4 weekly for 48 weeks. Clinical efficacy was assessed at intervals. Inflammation of the spine and sacroiliac joints (SIJs) on MRI was graded by the Spondyloarthritis Research Consortium of Canada (SPARCC) scoring system.

RESULTS

Twenty patients were assigned to GLM and 10 to PAM (83% men; age 33.4 ± 10.9 years; disease duration 4.4 ± 3.4 years). The baseline characteristics of the two groups were similar. At week 48, the proportions of patients who achieved an ASAS20 response were not significantly different between the GLM and PAM groups (65% vs. 56%; p = 0.69). Although there were no differences in BASDAI, spinal pain, and Medical Outcomes Study 36-item Short Form Health Survey (SF-36) scores between the two groups at week 48, the Ankylosing Spondylitis Disease Activity Score (ASDAS), Bath AS Functional Index (BASFI), C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) levels were significantly lower in GLM-treated patients. The SPARCC scores of the spine and SIJs decreased significantly in GLM- but not in PAM-treated patients. The differences in SPARCC scores between the two groups at week 48 were statistically significant. The frequency of adverse events (AEs) was similar in both arms.

CONCLUSIONS

In patients with aSpA, the clinical response rate and improvement in pain and quality of life (QoL) were similar between GLM and PAM groups after 48 weeks. However, significant reduction in inflammatory markers and MRI inflammation was only observed with GLM treatment.

Prenylated xanthones from mangosteen as promising cholinesterase inhibitors and their molecular docking studies

Garcinia mangostana is a well-known tropical plant found mostly in South East Asia. The present study investigated acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities of G. mangostana extract and its chemical constituents using Ellman's colorimetric method. Cholinesterase inhibitory-guided approach led to identification of six bioactive prenylated xanthones showing moderate to potent cholinesterases inhibition with IC50 values of lower than 20.5 μM. The most potent inhibitor of AChE was garcinone C while γ-mangostin was the most potent inhibitor of BChE with IC50 values of 1.24 and 1.78 μM, respectively. Among the xanthones, mangostanol, 3-isomangostin, garcinone C and α-mangostin are AChE selective inhibitors, 8-deoxygartanin is a BChE selective inhibitor while γ-mangostin is a dual inhibitor. Preliminary structure-activity relationship suggests the importance of the C-8 prenyl and C-7 hydroxy groups for good AChE and BChE inhibitory activities. The enzyme kinetic studies indicate that both α-mangostin and garcinone C are mixed-mode inhibitors, while γ-mangostin is a non-competitive inhibitor of AChE. In contrast, both γ-mangostin and garcinone C are uncompetitive inhibitors, while α-mangostin is a mixed-mode inhibitor of BChE. Molecular docking studies revealed that α-mangostin, γ-mangostin and garcinone C interacts differently with the five important regions of AChE and BChE. The nature of protein-ligand interactions is mainly hydrophobic and hydrogen bonding. These bioactive prenylated xanthones are worthy for further investigations.

Dispersive infrared spectroscopy measurements of atmospheric CO₂ using a Fabry-Pérot interferometer sensor

In this paper, we present the first dispersive infrared spectroscopic (DIRS) measurement of atmospheric carbon dioxide (CO2) using a new scanning Fabry-Pérot interferometer (FPI) sensor. The sensor measures the optical spectra in the mid infrared (3,900 nm to 5,220 nm) wavelength range with full width half maximum (FWHM) spectral resolution of 78.8 nm at the CO2 absorption band (~4,280 nm) and sampling resolution of 20 nm. The CO2 concentration is determined from the measured optical absorption spectra by fitting it to the CO2 reference spectrum. Interference from other major absorbers in the same wavelength range, e.g., carbon monoxide (CO) and water vapor (H2O), was taken out by including their reference spectra in the fit as well. The detailed descriptions of the instrumental setup, the retrieval procedure, a modeling study for error analysis as well as laboratory validation using standard gas concentrations are presented. An iterative algorithm to account for the non-linear response of the fit function to the absorption cross sections due to the broad instrument function was developed and tested. A modeling study of the retrieval algorithm showed that errors due to instrument noise can be considerably reduced by using the dispersive spectral information in the retrieval. The mean measurement error of the prototype DIRS CO2 measurement for 1 minute averaged data is about ±2.5 ppmv, and down to ± 0.8ppmv for 10 minute averaged data. A field test of atmospheric CO2 measurements were carried out in an urban site in Hong Kong for a month and compared to a commercial non-dispersive infrared (NDIR) CO2 analyzer. 10 minute averaged data shows good agreement between the DIRS and NDIR measurements with Pearson correlation coefficient (R) of 0.99. This new method offers an alternative approach of atmospheric CO2 measurement featuring high accuracy, correction of non-linear absorption and interference of water vapor.

Development of systemic lupus erythematosus in a male-to-female transsexual: the role of sex hormones revisited

Systemic lupus erythematosus (SLE) predominantly affects women of childbearing age. The infrequency of SLE in men and disease onset in prepubertal or postmenopausal women suggests a role of estrogen in the predisposition to the disease. Patients with hypergonadotrophic hypogonadism are prone to the development of SLE, and the use of exogenous estrogens in women increases the relative risk of SLE onset and disease flares. These observations provide indirect evidence for an opposite role of estrogens and androgens in the pathogenesis of SLE. We report on a male-to-female transsexual who developed SLE 20 years after sex-reassignment surgery and prolonged estrogen therapy. The role of sex hormones in SLE is revisited.

Expression of anti-inflammatory macrophage genes within skeletal muscle correlates with insulin sensitivity in human obesity and type 2 diabetes

AIMS/HYPOTHESIS

Low-grade systemic inflammation and adipose tissue inflammatory macrophages are frequently detected in patients with obesity and type 2 diabetes. Whether inflammatory macrophages also increase in skeletal muscle of individuals with metabolic disorders remains controversial. Here, we assess whether macrophage polarisation markers in skeletal muscle of humans correlate with insulin sensitivity in obesity and type 2 diabetes.

METHODS

Skeletal muscle biopsies were obtained from individuals of normal weight and with normal glucose tolerance (NGT), and overweight/obese individuals with or without type 2 diabetes. Insulin sensitivity was determined by euglycaemic-hyperinsulinaemic clamps. Expression of macrophage genes was analysed by quantitative RT-PCR.

RESULTS

Gene expression of the inflammatory macrophage phenotype marker cluster of differentiation (CD)11c was higher in muscle of type 2 diabetes patients (p = 0.0069), and correlated with HbA1c (p = 0.0139, ρ = 0.48) and fasting plasma glucose (p = 0.0284, ρ = 0.43), but not after correction for age. Expression of TGFB1, encoding the anti-inflammatory marker TGF-β1, correlated inversely with HbA1c (p = 0.0095, ρ = -0.50; p = 0.0484, ρ = -0.50) and fasting plasma glucose (p = 0.0471, ρ = -0.39; p = 0.0374, ρ = -0.52) in two cohorts, as did HbA1c with gene expression of macrophage galactose-binding lectin (MGL) (p = 0.0425, ρ = -0.51). TGFB1 expression was higher in NGT individuals than in individuals with type 2 diabetes (p = 0.0303), and correlated with low fasting plasma insulin (p = 0.0310, ρ = -0.42). In exercised overweight/obese individuals, expression of genes for three anti-inflammatory macrophage markers, MGL (p = 0.0031, ρ = 0.71), CD163 (p = 0.0268, ρ = 0.57) and mannose receptor (p = 0.0125, ρ = 0.63), correlated with high glucose-disposal rate.

CONCLUSIONS/INTERPRETATION

Muscle expression of macrophage genes reveals a link between inflammatory macrophage markers, age and high glycaemia, whereas anti-inflammatory markers correlate with low glycaemia and high glucose-disposal rate.

Thoracoscopic resection of congenital cystic lung lesions is associated with better post-operative outcomes

INTRODUCTION

The incidence of congenital cystic lung lesions has been increasing in recent years due to better antenatal detection. With the introduction and maturation of thoracoscopy, the operative management for these lesions has seen advancement in the last decade. In this study, we aimed to compare the post-operative outcomes of patients who had thoracoscopic resection with those who underwent open resection.

METHODS

A retrospective review of all patients who underwent surgery for congenital cystic lung lesions between January 1996 and June 2012 in a tertiary referral center was conducted. Patients' demographics, operative procedures and post-operative outcomes were analyzed.

RESULTS

Sixty-seven patients were identified over the past 15 years. Thirty-nine patients had thoracoscopic resections and 28 had open resections. Thirteen patients in the thoracoscopic group required conversion. Both groups had similar demographics in terms of age, body weight and laterality of lesions. The mean operative time and blood loss in the two groups were comparable. Patients in the thoracoscopic group had significantly shorter duration of chest tube drainage (4.3 vs. 6.9 days, p = 0.004), shorter intensive care unit stay (2.5 vs. 5.9 days, p = 0.003) and shorter hospital stay (6.9 vs. 12.0 days, p < 0.001). Post-operative complication rate was similar between the two groups. Patients with body weight less than 5 kg showed a significantly higher conversion to open surgery as compared to those with body weight more than 5 kg (62.5 vs. 25.8 %, p = 0.049).

CONCLUSION

Successful thoracoscopic resection for congenital cystic lung lesions results in better post-operative outcomes. However, this technique remains technically challenging in patients with body weight less than 5 kg.

Rituximab is associated with improved survival for aggressive B cell CNS lymphoma

BACKGROUND

The optimal treatment strategy in patients with aggressive B cell central nervous system lymphoma suitable to receive intensive therapy is unknown. The benefit of incorporating rituximab in systemic therapy remains unclear. We performed a retrospective study examining the impact of rituximab in the context of concomitant therapies, including methotrexate, cytarabine, and radiotherapy, in patients treated with curative intent at 4 university teaching hospitals during 1996-2011.

METHODS

A retrospective study of CNS lymphoma cases treated at the participating institutions was performed in accordance with institutional ethical guidelines. Patients were included if they received a diagnosis of primary diffuse large B cell lymphoma of the CNS, were HIV negative, and were treated with curative intent.

RESULTS

One hundred twenty patients aged 21-81 years were identified. Rituximab recipients and nonrecipients were similar, except for rituximab recipients being more likely to have received a diagnosis after 2004. The median follow-up of surviving patients was 30 months. The 5-year overall survival was 46%. Univariate analysis revealed age ≤60 years, ECOG performance status ≤1, normal lactate dehydrogenase, diagnosis after 2004, and treatment with cytarabine and rituximab as predictive of favorable overall survival. Multivariate analysis identified age to be an independent predictor of overall survival, with a trend toward improved survival from the other variables that were significant in univariate analyses.

CONCLUSIONS

In this retrospective analysis, the addition of rituximab to high-dose methotrexate-based chemotherapy in patients with aggressive B cell CNS lymphoma was associated with improved overall survival. Further studies are underway to prospectively validate these findings.

Glucocorticoid-induced avascular bone necrosis: diagnosis and management

Glucocorticoid use is one of the most important causes of avascular bone necrosis (AVN). The pathogenesis of glucocorticoid-induced AVN is not fully understood but postulated mechanisms include fat hypertrophy, fat emboli and intravascular coagulation that cause impedance of blood supply to the bones. Data regarding the relationship between AVN and dosage, route of administration and treatment duration of glucocorticoids are conflicting, with some studies demonstrating the cumulative dose of glucocorticoid being the most important determining factor. Early recognition of this complication is essential as the prognosis is affected by the stage of the disease. Currently, there is no consensus on whether universal screening of asymptomatic AVN should be performed for long-term glucocorticoid users. A high index of suspicion should be exhibited for bone and joint pain at typical sites. Magnetic resonance imaging (MRI) or bone scintigraphy is more sensitive than plain radiograph for diagnosing early-stage AVN. Conservative management of AVN includes rest and reduction of weight bearing. Minimization of glucocorticoid dose or a complete withdrawal of the drug should be considered if the underlying conditions allow. The efficacy of bisphosphonates in reducing the rate of collapse of femoral head in AVN is controversial. Surgical therapy of AVN includes core decompression, osteotomy, bone grafting and joint replacement. Recent advances in the treatment of AVN include the use of tantalum rod and the development of more wear resistant bearing surface in hip arthroplasty.

Enhanced activity of antifungal drugs using natural phenolics against yeast strains of Candida and Cryptococcus

AIMS

Determine whether certain, natural phenolic compounds enhance activity of commercial antifungal drugs against yeast strains of Candida and Cryptococcus neoformans.

METHODS AND RESULTS

Twelve natural phenolics were examined for fungicidal activity against nine reference strains of Candida and one of C. neoformans. Six compounds were selected for synergistic enhancement of antifungal drugs, amphotericin B (AMB), fluconazole (FLU) and itraconazole (ITR). Matrix assays of phenolic and drug combinations conducted against one reference strain, each, of Candida albicans and C. neoformans showed cinnamic and benzoic acids, thymol, and 2,3- and 2,5-dihydroxybenzaldehydes (-DBA) had synergistic interactions depending upon drug and yeast strain. 2,5-DBA was synergistic with almost all drug and strain combinations. Thymol was synergistic with all drugs against Ca. albicans and with AMB in C. neoformans. Combinations of benzoic acid or thymol with ITR showed highest synergistic activity. Of 36 combinations of natural product and drug tested, none were antagonistic.

CONCLUSIONS

Relatively nontoxic natural products can synergistically enhance antifungal drug activity, in vitro.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is a proof-of-concept, having clinical implications. Natural chemosensitizing agents could lower dosages needed for effective chemotherapy of invasive mycoses. Further studies against clinical yeast strains and use of animal models are warranted.

Proteomics of hepatocellular carcinoma: serum vimentin as a surrogate marker for small tumors (<or=2 cm)

Small hepatocellular carcinomas (HCCs) can be effectively cured by surgery with good clinical outcomes. However, the conventional AFP marker is ineffective in detecting small tumors. Here we employed a proteomic profiling approach to identify a candidate marker for HCC (<or=2 cm) in tumor tissues and then evaluate its clinical feasibility in patients' sera. The study was divided into 2 phases. (i) Biomarker discovery: we collected 76 frozen liver tissues (40 HCC and 36 controls) for proteomics profiling. Candidate protein markers were identified by MALDI-TOF/TOF and confirmed by immunoblot and qPCR. (ii) Clinical evaluation: Selected biomarker was tested by ELISA for sensitivity and specificity using serum samples from a separate cohort of 152 subjects (88 HCC and 64 controls). Vimentin was found significantly overexpressed in HCC, in particular the small-size subgroup (<or=2 cm) with p < 0.01. When tested in the serum samples, vimentin level was significantly higher in small tumors than the non-neoplastic controls (AUC = 0.69 and p < 0.01). Further analysis suggested that elevated circulating vimentin level could detect small HCC at 40.91% sensitivity and 87.50% specificity. Moreover, vimentin was found to be superior to serum AFP assayed at different cut-offs in detecting small tumors. When combined with AFP, the detection sensitivity and specificity could be further enhanced to 58.77 and 98.15%, respectively. In conclusion, serum vimentin is a potential surrogate marker, either alone or in combination with AFP, for detection of small HCCs.

Use of chemosensitization to overcome fludioxonil resistance in Penicillium expansum

AIM

To overcome fludioxonil resistance of Penicillium expansum, a mycotoxigenic fungal pathogen causing postharvest decay in apple, by using natural phenolic chemosensitizing agents.

METHODS AND RESULTS

Fludioxonil-resistant mutants of P. expansum were co-treated with different oxidising and natural phenolic agents. Resistance was overcome by natural phenolic chemosensitizing agents targeting the oxidative stress-response pathway. These agents also augmented effectiveness of the fungicide, kresoxim-methyl. Results indicated that alkyl gallates target mitochondrial respiration and/or its antioxidation system. Fungal mitochondrial superoxide dismutase (Mn-SOD) plays a protective role against alkyl gallates.

CONCLUSIONS

Natural chemosensitizing agents targeting the oxidative stress-response system, such as Mn-SOD, can synergize commercial fungicides.

SIGNIFICANCE AND IMPACT OF THE STUDY

Redox-active compounds can serve as potent chemosensitizing agents to overcome resistance and lower effective dosages of fungicides. This can reduce costs with coincidental lowering of environmental and health risks.

Intelligent fusion of cup-to-disc ratio determination methods for glaucoma detection in ARGALI

Glaucoma is a leading cause of permanent blindness. ARGALI, an automated system for glaucoma detection, employs several methods for segmenting the optic cup and disc from retinal images, combined using a fusion network, to determine the cup to disc ratio (CDR), an important clinical indicator of glaucoma. This paper discusses the use of SVM as an alternative fusion strategy in ARGALI, and evaluates its performance against the component methods and neural network (NN) fusion in the CDR calculation. The results show SVM and NN provide similar improvements over the component methods, but with SVM having a greater consistency over the NN, suggesting potential for SVM as a viable option in ARGALI.

Clinical experience in managing pediatric patients with ultra-short bowel syndrome using omega-3 fatty acid

Total parenteral nutrition (TPN) remains an important component of the management of short bowl syndrome in pediatric patients. However, prolonged TPN is known to be associated with cholestasis. Recently, the use of omega-3-fatty acid (Omegaven) has been proposed to improve TPN cholestasis. We present the early outcome after administration of Omegaven in four patients with ultra-short bowel syndrome. Based on our experience, it appears that omega-3 fatty acid can reverse and prevent the advent of TPN-related cholestasis, thereby significantly improving the process of intestinal adaptation. We suggest that clinicians consider this treatment option before proceeding to invasive surgery to reverse cholestasis. Prospective randomized trials are necessary to define a standard protocol and elucidate other potential benefits of this novel agent.

Laparoscopic hernioplasties in children: the implication on contralateral groin exploration for unilateral inguinal hernias

BACKGROUND

Inguinal hernias are commonly seen in the paediatric population. Controversies still exist regarding the need for contralateral groin exploration when an unilateral inguinal hernia is presented, since the true incidence of contralateral patent processus vaginalis is not known. With the advent of laparoscopic hernioplasty, the status of the contralateral side can be evaluated at the same setting. Here, we describe our experience in this issue after the introduction of laparoscopic hernioplasty in our unit.

METHODS

A retrospective review was carried out between October 2002 and January 2008. All patients presented with unilateral inguinal hernias were included. The demographics of the patients and the operative findings at laparoscopy were recorded. Statistics were performed using Student t-test or chi(2) test as appropriate and p < 0.05 was taken as statistically significant.

RESULTS

During the study period, 363 children were included in our study, of which there were 292 males and 71 females. 212 patients presented with right-sided hernias and 151 were left-sided. The mean age of patients at presentation was 48.8 months. The incidence of contralateral PPV overall was 39.7%. There was no decrease in incidence of having a contralateral inguinal hernia in relation to age.

CONCLUSION

Laparoscopy can accurately diagnose contralateral PPV in children who undergo unilateral inguinal hernia repair and thus holds an advantage over open herniotomy. Furthermore, there should not be an age criteria for contralateral exploration for surgeons who perform open herniotomy.

1700 Victims of intimate partner violence: characteristics and clinical outcomes

OBJECTIVE

To investigate the demographics and clinical outcomes of intimate partner violence victims presenting to an emergency department.

DESIGN

Retrospective, observational study.

SETTING

Emergency department of a regional hospital in Hong Kong.

PATIENTS

Adults presented with intimate partner violence during years 1999 to 2004.

RESULTS

We assessed 1695 victims of intimate partner violence with a mean age of 39 (range, 18-84) years, of whom 87% were female. Most of the patients were in the age-group of 31 to 40 years and the overall male-to-female ratio was 1:7. In Tin Shui Wai and Yuen Long districts, such cases appeared to be on the increase. Nearly two thirds (65%) of all the victims presented to the emergency department outside the office hours of medical social workers. Approximately 10% had been abused once before, and 40% more than twice. The head (39%), face (30%), upper limbs (37%), and lower limbs (17%) were commonly the injured parts. The majority (73%) had mild injuries; severe injuries being relatively less common. The latter included lacerations or cuts (6.6%), nasal bone fractures (0.3%), limb fractures (0.8%), and ruptured tympanic membranes (0.9%). In-patient management was undertaken for 8% of the victims, due to physical injury in 68% of these individuals and psychological trauma in the remaining 32%. The hospital admission rate dropped from 12% in 2001 to 4% in 2004.

CONCLUSIONS

Variations in demographic data had a significant impact on future service planning and management of intimate partner violence. Accident and Emergency Department and Emergency Medicine Ward services together with extended social worker support could provide timely, multidisciplinary care to meet the various needs of victims and subsequently reduce hospital admissions.

Bioavailability and Pharmacokinetics of Acyclovir Tablet Preparation

The bioavailability of a generic preparation of acyclovir (Avorax) was compared with the innovator product, Zovirax. Twelve healthy volunteers participated in the study, conducted according to a randomized, two-way crossover design. The preparations were compared using the parameters area under the plasma concentration time curve (AUC(0-infinity), peak plasma concentration (Cmax), and time to reach peak plasma concentration (Tmax). No statistically significant difference was observed between the Tmax or the logarithmic transformed AUC(0-infinity) and C(max) values of the two preparations. In addition, the 90% confidence interval for the ratio of the logarithmic transformed AUC(0-infinity) values of Avorax over those of Zovirax was found to lie between 0.85 and 1.06, while that of the logarithmic transformed Cmax values was between 0.95 and 1.25, being within the bioequivalence limit of 0.80-1.25. Moreover, the elimination rate constant (k(e)), elimination half-life (t(1/2)), and apparent volume of distribution (Vd) values obtained with the two preparations were comparable and not significantly different statistically.

The impact of psychological abuse by an intimate partner on the mental health of pregnant women

Objective

The objective of this first population-based study in Hong Kong was to assess the impact of psychological abuse by an intimate partner on the mental health of pregnant women.

Design

Survey.

Setting

Antenatal clinics in seven public hospitals in Hong Kong.

Population

Three thousand two hundred and forty-five pregnant women.

Methods

The Abuse Assessment Screen (AAS) and demographic questionnaires were administered face-to-face at 32–36 weeks of gestation. At 1 week postpartum, the AAS, Edinburgh Postnatal Depression Scale and SF-12 Health Survey were administered by telephone.

Main outcome measures

Intimate partner violence, postnatal depression and health-related quality of life.

Results

Two hundred and ninety six (9.1%) of the participants reported abuse by an intimate partner in the past year. Of those abused, 216 (73%) reported psychological abuse only and 80 (27%) reported physical and/or sexual abuse. Forty six (57.5%) in the physical and/or sexual abuse group also reported psychological abuse. Women in the psychological abuse only group had a higher risk of postnatal depression compared with nonabused women (adjusted OR: 1.84, 95% CI: 1.12–3.02). They were also at a higher risk of thinking about harming themselves (adjusted OR: 3.50, 95% CI: 1.49–8.20) and had significantly poorer mental health-related quality of life (P < 0.001). The higher risks of postnatal depression and thinking of harming themselves were not observed in the physical and/or sexual abuse group although significantly poorer mental health-related quality of life (P < 0.001) was observed.

Conclusions

Psychological abuse by an intimate partner against pregnant women has a negative impact on their mental health postdelivery. Furthermore, psychological abuse in the absence of physical and/or sexual abuse can have a detrimental effect on the mental health of abused women. The findings underscore the importance of screening pregnant women for abuse by an intimate partner and the need for developing, implementing and evaluating interventions to address psychological abuse.

Please cite this paper as: Tiwari A, Chan K, Fong D, Leung W, Brownridge D, Lam H, Wong B, Lam C, Chau F, Chan A, Cheung K, Ho P. The impact of psychological abuse by an intimate partner on the mental health of pregnant women. BJOG 2008;115:377–384.

Reference values for kaolin-activated thromboelastography in healthy children

BACKGROUND

The hemostatic system of children changes with age and differs significantly from the hemostatic system of adults. Age-specific reference values are therefore required for most hemostatic variables. Thromboelastography (TEG) is a point-of-care coagulation test that may provide superior evaluation and management of coagulopathies after cardiac surgery, when large-dose unfractionated heparin is administered for cardiopulmonary bypass. In this study, we established reference values for kaolin-activated TEG in healthy children, to facilitate accurate interpretation of pediatric TEG results.

METHODS

Kaolin-activated TEG was performed on 100 healthy children undergoing elective day surgery and 25 healthy adult volunteers. The following TEG variables were recorded: reaction time, coagulation time, alpha angle, maximum amplitude, percentage lysis 30 min after maximum amplitude was reached, and the coagulation index. Differences between age-groups were evaluated using analysis of variance.

RESULTS

Age-specific reference values for kaolin-activated TEG in healthy children between 1 mo and 16 yr of age are presented. No significant differences between children and adults were observed.

CONCLUSIONS

TEG results, from a particular clinical setting, must be compared to age-specific, as well as analyzer- and activator-specific, reference values to allow for correct interpretation of the results. Reference values provided here will be of use in acute clinical situations where a practical monitor of hemostasis is required.

Enhanced activity of strobilurin and fludioxonil by using berberine and phenolic compounds to target fungal antioxidative stress response

AIMS

Identify natural products that effectively target antioxidative signal transduction/stress response systems [i.e., mitogen-activated protein kinase (MAPK) pathway, mitochondrial superoxide dismutase (Mn-SOD)] of fungi. Enhance activity of strobilurin or fludioxonil with discovered compounds.

METHODS AND RESULTS

Enhancement of antifungal activity of strobilurins, inhibitors of complex III of the mitochondrial respiratory chain, was tested using berberine hemisulfate and different phenolic compounds. The Saccharomyces cerevisiae sod2Delta, a deletion mutant lacking Mn-SOD gene, was highly sensitive to berberine and veratraldehyde. Functional complementation analysis verified these compounds target Mn-SOD. Activity of strobilurin (25-50 micromol l(-1)) was elevated on most aspergilli and Penicillium expansum by co-application with berberine or veratraldehyde (2-4 mmol l(-1)). These compounds also prevented Aspergillus fumigatus MAPK mutants (sakADelta and mpkCDelta) from escaping toxicity of fludioxonil (a phenylpyrrole fungicide potentiated by the MAPK pathway), a typical phenotype of fungal MAPK mutants.

CONCLUSIONS

Strobilurin activity or prevention of fungal escape from fludioxonil toxicity can be enhanced by co-application of certain alkaloids or phenolics.

SIGNIFICANCE AND IMPACT OF THE STUDY

Natural products can be used to target cellular stress response systems in fungal pathogens and serve as alternatives/additives to commercial antifungal agents.

Identifying intimate partner violence: comparing the Chinese Abuse Assessment Screen with the Chinese Revised Conflict Tactics Scales

OBJECTIVE

To assess the measurement accuracy and the utility of the Chinese Abuse Assessment Screen (AAS).

DESIGN

A cross-sectional study.

SETTING

An antenatal clinic of a public hospital and a community centre in Hong Kong.

SAMPLE

A total of 257 Chinese women consisting of 100 pregnant women and 157 nonpregnant women.

METHOD

The Chinese AAS was administered first, followed by the Chinese Revised Conflict Tactics Scales (CTS2). This was performed in the same sitting, and each participant was interviewed once either at an antenatal clinic (for the pregnant women sample) or at a community centre (for the nonpregnant women sample).

MAIN OUTCOME MEASURES

Estimates of the sensitivity, specificity, positive and negative predictive values and positive and negative likelihood ratios.

RESULTS

Using the Chinese CTS2 as the standard, the specificity estimates of the Chinese AAS for emotional, physical and sexual abuse were > or = 89%, while the sensitivity estimates varied from 36.3 to 65.8%. The sensitivity improved in the screening for more severe cases (66.7%). The positive predictive values were > or = 80%, and the negative predictive values varied from 66 to 93%. Factors such as the age difference between the couple and the woman's need for financial assistance were found to be associated with intimate partner violence (IPV).

CONCLUSION

The Chinese AAS has demonstrated satisfactory measurement accuracy and utility for identifying IPV when the Chinese CTS2 was used as the standard.

Modeling the transport of metals with rate-limited EDTA-promoted extraction and dissolution during EDTA-flushing of copper-contaminated soils

EDTA-flushing of artificially contaminated soils enhanced Cu extraction but also induced mineral dissolution simultaneously. The mobilization and transport of these metal-EDTA complexes was investigated with column experiments. A quantitative transport model was proposed for simulating the experimental breakthrough curves of Cu, Fe, Al, and Ca. The rate-limited EDTA-promoted extraction and dissolution could be described by respective second-order kinetic terms, which were necessary for explaining the time-dependent depletion of extractable metals (sorbed and indigenous) in soils with continuous EDTA-flushing. Simultaneous simulation of extraction of sorbed Cu and dissolution of soil Fe, Al, and Ca is more conceptually accurate than individual modeling of each metal because the latter approach tends to overestimate the concentration of free EDTA during transport and thus underestimate the rate coefficients of EDTA-promoted dissolution. The fitted rate coefficients of Cu were about an order of magnitude larger than those of Fe and Al; these values probably reflect Cu extraction from weakly sorbed fractions and Fe and Al dissolution from amorphous oxides. The apparent retardation of Fe, Al, and Ca transport had to be taken into account by empirical determination, which was attributed to the metal lability in soils and thermodynamics of surface complexation.

Extraction of brain tumor from MR images using one-class support vector machine

A novel image segmentation approach by exploring one-class support vector machine (SVM) has been developed for the extraction of brain tumor from magnetic resonance (MR) images. Based on one-class SVM, the proposed method has the ability of learning the nonlinear distribution of the image data without prior knowledge, via the automatic procedure of SVM parameters training and an implicit learning kernel. After the learning process, the segmentation task is performed. The proposed technique is applied to 24 clinical MR images of brain tumor for both visual and quantitative evaluations. Experimental results suggest that the proposed query-based approach provides an effective and promising method for brain tumor extraction from MR images with high accuracy.