The differential role of SSa/SSb and Ro52 antibodies in defining clinical phenotypes in idiopathic inflammatory myopathies

OBJECTIVE

In idiopathic inflammatory myopathies, anti-SSa/SSb and anti-Ro52 are associated with interstitial lung disease (ILD), yet few studies have compared their prognostic utility. Our study analyzes clinical phenotypes associated with anti-SSa/SSb and anti-Ro52 positivity in IIM and their association with ILD.

METHODS

We performed a retrospective analysis of IIM patients >18-years-old, seen at Northwell Myositis Center 2007- 2018 who met 2017 EULAR/ACR criteria with available anti-SSa/SSb data. Patients who were anti-SSa/SSb(-) and anti-Ro52(+) were excluded from anti-SSa/SSb subgroup analysis but included in Ro52 subgroup analysis. Organ manifestations, pulmonary function tests (PFTs) and comorbidities were recorded. Statistical analyses included Chi-square, Fisher's Exact, Wilcoxon Rank Sum, McNemar's test.

RESULTS

Of 94 patients included in the final analysis, 35% (33/94) were anti-SSa/SSb positive (+). Of 60 patients with anti-Ro52 data, 42% (25/60) were (+). ILD was more common in anti-SSa/SSb (+) versus anti-SSa/SSb negative patients and anti-Ro52(+) versus anti-Ro52 negative patients (58% vs 25%; p = 0.003 and 64% vs.26%; p = 0,004 respectively). Anti-SSa/SSb (+) was not associated with increased ILD severity based on PFTs. Anti-Ro52(+) group had lower DLCO than anti-Ro52(-) (47% vs 68%; p = 0.003). Anti-SSa/SSb positivity did not confer a difference in the frequency of other manifestations. Elevated rates of venous thromboembolism (VTE) (10%-12%) and osteoporosis (13-17%) were observed independent of anti-SSa/SSb or anti-Ro52 status.

CONCLUSION

In IIM anti-SSa/SSb or anti-Ro52 positivity is associated with higher ILD rate. Both assays are useful to confer ILD risk, but anti-Ro52 is more predictive of severe ILD. High frequencies of osteoporosis and VTE were observed in all subgroups.

Brain-Derived Neurotrophic Factor as a Potential Mediator of the Beneficial Effects of Myo-Inositol Supplementation during Suckling in the Offspring of Gestational-Calorie-Restricted Rats

This study aims to investigate the potential mechanisms underlying the protective effects of myo-inositol (MI) supplementation during suckling against the detrimental effects of fetal energy restriction described in animal studies, particularly focusing on the potential connections with BDNF signaling. Oral physiological doses of MI or the vehicle were given daily to the offspring of control (CON) and 25%-calorie-restricted (CR) pregnant rats during suckling. The animals were weaned and then fed a standard diet until 5 months of age, when the diet was switched to a Western diet until 7 months of age. At 25 days and 7 months of age, the plasma BDNF levels and mRNA expression were analyzed in the hypothalamus and three adipose tissue depots. MI supplementation, especially in the context of gestational calorie restriction, promoted BDNF secretion and signaling at a juvenile age and in adulthood, which was more evident in the male offspring of the CR dams than in females. Moreover, the CR animals supplemented with MI exhibited a stimulated anorexigenic signaling pathway in the hypothalamus, along with improved peripheral glucose management and enhanced browning capacity. These findings suggest a novel connection between MI supplementation during suckling, BDNF signaling, and metabolic programming, providing insights into the mechanisms underlying the beneficial effects of MI during lactation.

Racial Disparities in Diagnosis and Treatment of Patients With Dermatomyositis of Different Skin Tones

BACKGROUND

Delays in the diagnosis and treatment of dermatological conditions in minorities are a well-documented health disparity. We aimed to determine if there was a delay in detection and treatment initiation for dermatomyositis (DM) and amyopathic dermatomyositis (ADM) in patients of different skin tones.

METHODS

Patients from Montefiore Medical Center who met the criteria for DM and ADM were included in this cohort study. Records were reviewed for date of first documented rash, creatine kinase levels, muscle weakness complaints, and date of first steroid or disease-modifying antirheumatic drug initiation. The median number of days between rash documentation and therapy initiation was compared for patients of different races, including non-Hispanic White, non-Hispanic Black, Hispanic, and other (Asian and unknown). Data were compared in White versus non-White skin.

RESULTS

Sixty-three DM and 9 ADM patients met the inclusion criteria. There was a shorter time to treatment initiation in White versus non-White patients, with a median number of 8 days compared with 21 days, respectively ( p = 0.05). Kaplan-Meier curves showed prolonged time to diagnosis and treatment in all other races when compared with White patients ( p = 0.03).

DISCUSSION

It took clinicians longer to diagnose and treat DM and ADM in patients of color. The trends observed emphasize the importance of increasing dermatology education of non-White skin to improve detection and treatment of DM and ADM and minimize health disparities.

Two Cases of Venous Thromboembolism Shortly After Adenovirus-Based COVID-19 Vaccination

As the coronavirus disease 2019 (COVID-19) global pandemic continues, multiple vaccines have been developed to decrease infection rate and number of deaths. Vaccine administration is especially important as new COVID-19 variants emerge. While the number of severe thromboembolic events reported after adenovirus-based vaccination has gained attention, there is little information regarding the presentation and management of post-vaccination venous thromboembolism (VTE). Here, we present two cases of VTE after the Janssen vaccine administration. In the first case, a 98-year-old African American female with hypertension developed bilateral lower extremity edema that evolved into unilateral lower extremity edema 20-35 days following the Janssen vaccine administration. She was found to have an extensive unilateral proximal femoral deep vein thrombosis (DVT) 35 days after the vaccination. In the second case, a 64-year-old African American female developed ecchymosis and unilateral edema six days after the Janssen vaccine administration. She was found to have proximal superficial vein thrombosis two days later. In both cases, laboratory data, including platelets and anti-heparin antibodies were within normal limits. Thus, VTE may be an adverse effect of the Janssen vaccine or any adenovirus-based vaccine, but further surveillance and investigation to elucidate this association are necessary. We advise practitioners to have a high index of suspicion for thrombosis after Janssen vaccine administration, regardless of the presence of thrombocytopenia, and avoidance of heparin products until heparin antibody results return.

A Case of Microscopic Polyangiitis Complicated by Mucormycosis: A Dangerous Balancing Act

Microscopic polyangiitis (MPA) is a rare antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis marked by renal involvement, which often leads to rapidly progressive glomerulonephritis. Immunosuppressive treatment is necessary to prevent irreparable organ damage. On the other hand, mucormycosis is a rare and devastating opportunistic fungal infection with a high mortality rate in both immunosuppressed and immunocompetent individuals. It requires a high index of suspicion at the time of diagnosis since any delay in treatment may lead to severe morbidity or death. Here, we present the case of a diabetic patient diagnosed with MPA who received partial induction treatment, subsequently developed mucormycosis, survived, yet required continued immunosuppressive treatment for active MPA while imaging was concerning for a persistent mucormycosis infection. This case highlights the barriers to early mucormycosis detection specific to vasculitis patients, mucormycosis considerations unique to the rheumatologic population, and discusses how to balance immunosuppressive treatment in the setting of a deadly opportunistic infection.

Prescribing Patterns of Hydroxychloroquine and Glucocorticoids Among Lupus Patients After New-Onset End-Stage Renal Disease

OBJECTIVE

Optimal strategies for managing lupus medications after end-stage renal disease (ESRD) have not been addressed. The objective was to identify the current US-wide prescribing patterns of hydroxychloroquine (HCQ) and oral glucocorticoids (GS) among systemic lupus erythematosus (SLE) patients with incident ESRD enrolled in the US Renal Data System (USRDS) registry.

METHODS

We identified incident ESRD patients age ≥18 years with SLE as a primary cause of ESRD between January 2006 and June 2013. Patients who were started on dialysis at ESRD onset and enrolled in Medicare Part D within 93 days as required by Medicare were included.

RESULTS

Among the 2,654 new-onset ESRD patients with Part D, the median duration of follow-up was 761 days (interquartile range [IQR] 374-1,375). At baseline, 1,076 patients (41%) were not receiving HCQ or GS, 220 (8%) were prescribed HCQ alone, 509 (19%) were prescribed both HCQ and GS, and 849 (32%) were prescribed GS alone. Of the 1,983 patients who either never received or discontinued HCQ after ESRD onset, 667 (34%) continued GS to the end of the follow-up period. The median GS dose was lower for patients taking HCQ (14 mg [IQR 9-21]) compared to patients who were never prescribed HCQ (15 mg [IQR 9-27]) or patients who discontinued HCQ after ESRD (17 mg [IQR 10-27]; P = 0.001).

CONCLUSION

Approximately one-third of patients with lupus nephritis and new-onset ESRD received GS monotherapy at high doses. As GS-related complications contribute to hospitalizations and deaths in SLE ESRD, changing these prescribing practices may improve morbidity and mortality outcomes.

Association of Hydroxychloroquine Dose With Adverse Cardiac Events in Patients With Systemic Lupus Erythematosus

OBJECTIVE

To determine whether hydroxychloroquine (HCQ) dose is associated with adverse cardiac outcomes in patients with systemic lupus erythematosus (SLE).

METHODS

Patients with SLE taking HCQ and with ≥1 echocardiogram followed at a tertiary care center in the Bronx, New York between 2005 and 2021 were included. The HCQ weight-based dose at the HCQ start date was the main exposure of interest. The outcome was incident all-cause heart failure with reduced ejection fraction (HFrEF), life-threatening arrhythmia, or cardiac death. We used Fine-Gray regression models with death as a competing event to study the association of HCQ dose with the outcome. Due to a significant interaction between smoking and HCQ exposure, models were stratified by smoking status. Propensity score analysis was performed as a secondary analysis.

RESULTS

Of 294 patients, 37 (13%) developed the outcome over a median follow-up time of 7.9 years (interquartile range [IQR] 4.2-12.3 years). In nonsmokers (n = 226), multivariable analysis adjusted for age, body mass index, hypertension, chronic kidney disease, diabetes mellitus, and thromboembolism showed that higher HCQ weight-based doses were not associated with an increased risk of the outcome (subdistribution hazard ratio [HR] 0.62 [IQR 0.41-0.92], P = 0.02). Similarly, higher baseline HCQ doses were not associated with a higher risk of the outcome among smokers (n = 68) (subdistribution HR 0.85 [IQR 0.53-1.34] per mg/kg, P = 0.48). Propensity score analysis showed comparable results.

CONCLUSION

Higher HCQ doses were not associated with an increased risk of HFrEF, life-threatening arrhythmia, or cardiac death among patients with SLE and may decrease the risk among nonsmokers.

Effect on cholesterol remnants and residual lipid risk with PCSK9 inhibitors: the LIPID-REAL Registry

Background

Monoclonal antibodies that inhibit the proprotein convertase subtilisin/kexin type 9 (PCSK9) reduce low-density lipoprotein cholesterol (LDLc) by 55%, regardless of baseline treatments. Nonetheless, the effect of other lipid parameters, as cholesterol remnants or, the so-called residual lipid risk, are unknown.

Methods

Multicenter and retrospective registry of patients treated with PCSK9 inhibitors from 14 different hospitals from Spain. Before and on-treatment lipid parameters were recorded. Cholesterol remnants were calculated by the equation: total cholesterol minus LDLc minus HDLc and values ≥30 were considered high. Residual lipid risk was estimated by 1) the estimation of LDL particle size, by the triglycerides/HDLc ratio (TG/HDL) and values <2 were assumed as low and dense LDL particles; 2) total cholesterol/HDLc (TC/HDL) and values >3 were considered high; and; 3) the triglycerides-to-glucose (TG/Gluc) index, obtained as the natural logarithm of (triglycerides * glucose/2)

Results

A total of 652 patients were analyzed, mean age 60.0 (10.5) years and 161 (24.69%) women. Baseline LDLc was 149.2 (49.9) mg/dl, cholesterol remnants 29.9 (20.3) mg/dl, TG/HDL 3.9 (4.1), TC/HDL 4.9 (1.9) and TG/Gluc index 8.9 (0.7). Most patients (92.3%) were on statins; 54.8% with ezetimibe, 8.5% with fibrates.

Evolocumab was initiated in 318 (56.6%) patients; 229 (40.7%) alirocumab 75 mg and 15 (2.7%) alirocumab 150 mg. Median time to second blood determination were 187.5 (IQR 101–242) days. Mean on-treatment LDLc was 67.46 (45.78) mg/dl what represented a 55% reduction. As shown in the figure, significant reduction in cholesterol remnants (p=0.017), TG/HDL ratio (p=0.020), TC/HDL ratio (p<0.001) and TG/Gluc index (p<0.001). The percentage of patients with remnants >30 mg/dl decreased: 34.62% to 30.07 (p<0.01). Significant reductions were also observed in the percentage of patients with TG/HDL >2 (71.25% to 61.98%; p<0.01) or TC/HDL >3 (94.28% to 38.97%; p<0.01)

Conclusions

This multicenter and retrospective registry of real-world patients treated with PCSK9 inhibitors demonstrates a positive effect on cholesterol remnants and lipid-residual risk beyond LDLc reductions.

Funding Acknowledgement

Type of funding sources: None.

Gender differences low-density lipoprotein cholesterol reduction with PCSK9 inhibitors in real world patients

Background

Monoclonal antibodies that inhibit the proprotein convertase subtilisin/kexin type 9 (PCSK9) reduce low-density lipoprotein cholesterol (LDLc) by 55%, regardless of baseline treatments, and are supposed to have a homogenous effect. We tested possible gender differences in a large multicenter registry of real-world patients treated with PCSK9 inhibitors.

Methods

Multicentre and retrospective registry of patients treated with PCSK9 inhibitors from 14 different hospitals from Spain. Before and on-treatment LDLc cholesterol was recorded as well as medical treatments, clinical indication and clinical features.

Results

A total of 562 patients were analysed, mean age 60.2 (9.6) years and 79.2% males. Most frequent indication for PCSK9 inhibitor treatment was established cardiovascular disease (CVD) with LDLc >100 mg/dl (58.1%) followed by familial hypercholesterolemia (23.4%) and statin intolerance (18.5%). Indications other than CVD were more frequent in women (53.3% vs. 39.1%; p=0.03). Women were more frequently ezetimibe (67.5% vs. 50.6%; p=0.001) before PCSK9 treatment; although no gender differences in statin use was observed (78.6% vs. 83.6%; p=0.93) in the whole cohort it was significantly lower in patients with coronary heart disease (91.4% vs. 98.9%; p=0.005). Before treatment LDLc was 148.7 (50.1) mg/dl and it was higher women vs. men (160.3 (59.3) vs. 145.6 (47.0); p=0.005). Evolocumab was initiated in 318 (56.6%) patients; 229 (40.7%) alirocumab 75 mg and 15 (2.7%) alirocumab 150 mg. No gender differences in PCSK9 inhibitors drug or dose were observed.

Median time to second blood determination were 187.5 (IQR 101–242) days. Mean on-treatment LDLc was 66.7 (46.4) mg/dl and it was also higher in women vs. men (84.4 (58.6) vs. 61.9 (41.3); p<0.001). Mean LDLc reduction was 54.7% but it was higher in men as compared to women (57.0% vs. 46.1%; p=0.0003). Higher LDLc reductions were also observed in patients with CVD as compared to the other 2 indications (57.1% vs. 47.3%; p=0.002). Moreover, LDLc reduction with PCSK9 inhibitors treatment was also higher in men vs women among patients with CVD (58.9% vs. 48.0%; p=0.04)

Conclusions

This multicentre and retrospective registry of real-world patients treated with PCSK9 inhibitors highlights significant gender differences in LDLc reduction.

Funding Acknowledgement

Type of funding sources: None.

Escherichia coli Dcu C4-dicarboxylate transporters dependent proton and potassium fluxes and FOF1-ATPase activity during glucose fermentation at pH 7.5

During fermentation in Escherichia coli succinate is transported via Dcu transporters, encoded dcuA, dcuB, dcuC and dcuD although the role of DcuD protein has not been elucidated yet. It has been shown contribution of Dcu transporters in the N,N'-dicyclohexylcarbodiimide (DCCD) sensitive proton and potassium transport through the cytoplasmic membrane and membrane-associated ATPase activity. Total H^± efflux was decreased ~ 40% while K^± uptake was absent in dcuD mutant. DCCD-sensitive H^± flux was absent in dcuD nevertheless it was increased ~ 3 fold in dcuACB. K^± uptake in dcuACB was stimulated ~ 30% compared to wild type but in DCCD assays K^± ions were effluxed with the rate of 0.15 mmol/min per 10⁹ cells/ml. In dcuACB mutant membrane potential (ΔΨ) was ~ 30 mV higher than in wild type. dcuD gene expression was increased in the dcuACB mutant respect to wild type at pH 7.5 (~120%), suggesting that an increment of DcuD activity compensates the lack of DcuA, DcuC and DcuB carriers. It can be concluded that active DcuD is important for H^± efflux via the F_OF₁-ATPase and K^± uptake at pH 7.5. In addition, DcuA, DcuB and DcuC transporters are crucial for regulating DCCD-sensitive K^± transport and ΔΨ in E. coli.

THU0276 HIGH HYDROXYCHLOROQUINE EXPOSURE IS ASSOCIATED WITH ABNORMAL STRAIN IMAGING IN LUPUS PATIENTS WITH END-STAGE RENAL DISEASE

Background:

Hydroxychloroquine (HCQ) cardiotoxicity remains an underrecognized condition. Diagnosis ultimately relies on invasive endomyocardial biopsy (EMB) and non-invasive screening methods are warranted. Strain imaging is a novel tool to detect early subclinical left ventricular (LV) dysfunction and may have a role in screening for HCQ cardiotoxicity (1). Strain measures systolic deformation indices that when decreased can predict cardiovascular outcomes more accurately than LV ejection fraction (2).

Objectives:

We assessed whether high HCQ cardiotoxicity risk is associated with a specific strain pattern in a group of patients with SLE and end-stage renal disease (ESRD).

Methods:

This was a retrospective study in a tertiary care center in New York on a group of patients with an established diagnosis of SLE, ESRD and cardiomyopathy on the index echocardiogram followed between years 2003 and 2019. The patients were stratified into two groups: high risk HCQ toxicity group was defined as either cumulative HCQ dose ≥1000g and/or an endomyocardial biopsy confirming HCQ toxicity. Low/moderate risk group was defined as a cumulative dose of HCQ <1000g. Clinical, demographic, electrocardiographic and echocardiographic strain parameters were compared between the groups.

Results:

A total of 16 patients were included. Two patients had EMB consistent with HCQ induced toxicity and 3 patients had cumulative HCQ doses ≥1000g. There were no significant differences in the baseline demographic characteristics between the two groups. Compared to patients with low/moderate risk, patients in the high risk group had a lower heart rate at the time of the echocardiogram (69 vs 87 beats per minute, p=0.08) and a higher frequency of LV hypertrophy (40% vs 9.1%, p=0.2). Strain analysis showed that both groups had compromised LV global longitudinal strain (GLS) and global cross-sectional strain (GCS). However, compared to the low/moderate risk group, the high risk group had a weaker LV GLS (-12.3% vs -14.9%, p=0.27).

Characteristics overall and stratified by HCQ risk group

CharacteristicOverall (n=16)Low/Moderate HCQ Risk(n=11)High HCQ Risk and/or Positive EMB (n=5)P valueDemographicsAge, years47.5 (36.5,60.7)50.0 (33.9,60.5)42.5 (42.7,61.0)0.95Female, n(%)14 (87.5)9 (90)5 (83.3)0.99Clinical FeaturesSLE duration, years7.4 (4.3,17.5)5.5 (3.5,13.2)15.6 (11.6,19.3)0.15HCQ cumulative dose, g422.8 (224.2,422.8)285.4 (110.8,523.6)1140 (1006,1625.4)0.005HCQ therapy duration, years3.4 (2.5, 8.9)3.2 (1.5,5.1)7.8 (6.8,11.6)0.06HCQ daily dose, mg/d226 (200,394.9)200 (179.4,253.7)400 (389.8,400)0.007Hypertension, n (%)14 (87.5)10 (90.9)4 (80.0)0.99Diabetes, n (%)3 (18.8)2 (18.8)1 (20.0)0.99CAD, n (%)3 (18.8)2 (18.8)1 (20)0.99EchocardiogramEF, %55 (42.5,60)55 (40,60)55 (55,70)0.45LA size, cm3.8 (3.4,4.3)3.8 (3.4,4.2)4.3 (3.4,4.9)0.30LVEDD, cm4.9 (4.4, 5.5)4.8 (4.2,5.5)5.0 (4.9,5.4)0.43E/E’12.3 (8.8,16.3)12 (8.8,14.9)16.9 (4.9,21.8)0.43Moderate-severe LV hypertrophy, n(%)3 (18.7)1 (9.1)2 (40.0)0.20Strain echocardiographyGLS, %-13.9 (-16.7,-12.3)-14.9 (-16.7,-12.9)-12.3 (-15.4,-12.2)0.27Base/Apex Ratio0.8 (0.7,0.9)0.76 (0.68,0.86)0.76 (0.66,0.83)0.95GCS, %-20.2 (-21.7,-17)-19.7 (-20.5,18.0)-21.7 (-23.9,-20.9)0.16RV GLS, %-20.19 (-22.1,-17.5)-20.2 (-22.3,-17.1)-19.8 (-22.1,-17.5)0.99

Conclusion:

We report an association of higher HCQ cardiotoxicity risk and impaired strain in a set of SLE ESRD patients. Standard echo measures did not differentiate between high and low/moderate risk patients. Although the findings did not reach statistical significance, given the small sample size, results are still suggestive of a possible utility of strain echocardiography for detection of early HCQ toxicity.

References:

[1]Buss SJ, et al. J Rheumatol. 2010;37(1):79-86

[2]Kalam K, et al. Heart. 2014;100(21):1673-80

Disclosure of Interests: None declared

SAT0172 UTILIZATION OF HYDROXYCHLOROQUINE AND CORTICOSTEROIDS AMONG LUPUS PATIENTS WITH INCIDENT END-STAGE RENAL DISEASE (ESRD) ONSET: A LONGITUDINAL STUDY USING USRDS REGISTRY

Background:

The development of ESRD due to lupus nephritis is one of the most common and serious complications of SLE. Mortality among SLE ESRD patients is 4-fold higher compared to lupus nephritis patients with preserved renal function1Mortality in SLE ESRD is also twice as high compared with non-SLE ESRD, even though SLE patients develop ESRD at a significantly younger age. In the absence of ESRD specific guidelines, medication utilization in SLE ESRD is unknown.

Objectives:

The objective of this study was to investigate the real-world current US-wide patterns of medication prescribing among lupus nephritis patients with new onset ESRD enrolled in the United States Renal Disease Systems (USRDS) registry. We specifically focused on HCQ and corticosteroids (CS) as the most used medications to treat SLE.

Methods:

Inclusion: USRDS patients 18 years and above with SLE as a primary cause of ESRD (International Classification of Diseases, 9thRevision (ICD9) diagnostic code 710.0, previously validated2). who developed ESRD between January 1st, 2006 and July 31, 2011 (to ensure at least 6 months of follow-up in the USRDS). Patients had to be enrolled in Medicare Part D (to capture pharmacy claims). The last follow-up date was defined as either the last date of continuous part D coverage or the end of the study period, Dec 31, 2013.

Results:

Of the 2579 patients included, 1708 (66%) were HCQ- at baseline, and 871 (34%) were HCQ+ at baseline. HCQ+ patients at baseline had a slightly lower duration of follow-up compared to HCQ- patients at baseline, median (IQR) of 2.32 (1.33, 3.97) years and 2.55 (1.44, 4.25) years, respectively, p= 0.02. During follow-up period, only 778 (30%) continued HCQ either intermittently or continuously to the last follow-up date, 1306 (51%) were never prescribed HCQ after baseline, and 495 (19%) discontinued HCQ before the last follow-up date. Of the 1801 patients who were either never prescribed or discontinued HCQ early after ESRD onset, 713 (40%) were prescribed CS to the end of the follow-up period: 55% were receiving a low dose <10mg/daily, and 43 were receiving moderate dose (10-20mg daily)

Conclusion:

HCQ may be underprescribed and CS may be overprescribed in SLE ESRD. Changing the current prescribing practices may improve outcomes in SLE ESRD

References:

[1]Yap DY et al., NDT 2012.

[2]Broder A et al., AC&R 2016.

Acknowledgments :

The data reported here have been supplied by the United States Renal Data System (USRDS). The interpretation and reporting of these data are the responsibility of the author(s) and in no way should be seen as an official policy or interpretation of the U.S. government.

Funding: :

NIH/NIAMS K23 AR068441 (A Broder), NIH/NIAMS R01 AR 057327 and K24 AR 066109 (KH Costenbader)

Disclosure of Interests: :

Anna R. Broder: None declared, Wenzhu Mowrey: None declared, Anna Valle: None declared, Beatrice Goilav: None declared, Kazuki Yoshida: None declared, Karen Costenbader Grant/research support from: Merck, Consultant of: Astra-Zeneca

[Analysis of causes and factors associated with hospital readmission in mild and moderate polythraumatism: An observational study]

BACKGROUND

Early readmissions (ER) occur during the 30 days after discharge, ER are common and expensive, associated with a decrease in the quality of care. The rate of ER in polytraumatic patients (PTP) is estimated between 4.3-15%. Our objective was to identify those factors associated with ER and its characteristics after suffering mild-moderate trauma in our area.

MATERIAL AND METHOD

This is a retrospective observational study, including data of patients with (PTP) mild or moderate admitted between July 2012 and June 2017 in our institution and their ER in public hospitals and/or outpatient centers. Demographic variables, diagnoses, procedures and characteristics of readmissions were collected. After a bivariant analysis was done, a Logistic regression had benn performed to determine risk factors for ER.

RESULTS

1013 patients were included, with median age of 38 years, ISS of 3 points and initial hospital stay of 1 day. 185 patients were readmitted (18.3%). Independent factors associated with ER were: injury mechanism, especially bicycle accident (OR 2.26), comorbidities highlighting HBP (OR 1.83) and COPD (OR 1.98), fracture immobilization (OR 1.99) and hospital admission in the initial care (OR 0.56). The causes of ER were: pain 61.6%, wound infection 15.1%, scheduled cures and deferred interventions 12.97%, medical 6.4% and psychiatric decompensation. 2.7% CONCLUSION: The ERs in mild-moderate PTP are multifactorial, our results show an association between factors such as injury mechanism, the presence of comorbidities and the procedures performed in the sentinel episode and the rate of ER. The implementation of simple interventions at discharge could reduce its incidence clearly.

A case of Moyamoya disease complicated by aHUS in a patient with a history of marginal zone B-cell lymphoma: lightning strikes thrice?

Atypical haemolytic uraemic syndrome (aHUS) is a rare, acquired thrombotic microangiopathy, mediated by complement activation, in very sick patients. Moyamoya is similarly a rare disease in which stenosis or occlusion of segment(s) of the anterior cerebral circulation leads to the formation of many thin collaterals. Other reports have described an association between HUS and Moyamoya disease in the paediatric population. However, this case study presents the exceptionally rare presentation of an adult with aHUS and Moyamoya disease in a patient who was treated with rituximab for marginal zone B-cell lymphoma.

5132Effect of PCSK9 inhibitors treatment on acute coronary syndrome and stroke incidence: a metanalysis of currently available clinical trials

Background

Proprotein convertase subtilisin–kexin type 9 (PCSK9) inhibitors have demonstrated to induce large reductions in low-density lipoprotein cholesterol (LDLc) and major cardiovascular events but none of the studies was statistically powered to demonstrate reductions in specific endpoints rather than a combined end-point of major cardiovascular events.

Methods

We performed an intention-to-treat meta-analysis in line with recommendations from the Cochrane Collaboration and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement using currently available studies involving PCSK9 inhibitors. The endpoint assessed were acute coronary syndrome (ACS) and stroke.

Results

We included 81,544 patients, 41,147 treated with a PSCK9 inhibitors: 17,179 with evolocumab; 13,718 with bococizumab and 10,250 with alirocumab (table 1). A total of 1,316 ACS were registered in the treatment group vs. 1,608 in controls, resulting in 18.0% reduction associated with PCSK9 treatment (figure 1). This result was reproduced exactly in the EBCT althougt a non-significant heterogeneity was detected (p=0.052). Metaregression analyses did not demonstrate the implication of the study (p=0.45), study drugs (p=0.26), age (p=0.89), hypertension (p=0.81) or diabetes (p=0.81) on such result.

Results on stroke incidence are presented in figure 2. PCSK9 inhibitors treatment resulted in a 24% reduction of stroke when all studies were analyzed together; heterogeneity was statistically significant (p=0.021) but it was not observed in the EBCT analysis where PCSK9 inhibitors were associated with 24% stroke incidence reduction.

Conclusions

The meta-analysis of currently available studies demonstrates that PCSK9 inhibitors treatment reduces the incidence of ACS by 18% and stroke by 24%.

The coagulation system helps control infection caused by the ciliate parasite Philasterides dicentrarchi in the turbot Scophthalmus maximus (L.)

Many studies have shown that coagulation systems play an important role in the defence against pathogens in invertebrates and vertebrates. In vertebrates, particularly in mammals, it has been established that the coagulation system participates in the entrapment of pathogens and activation of the early immune response. However, functional studies investigating the importance of the fish coagulation system in host defence against pathogens are scarce. In the present study, injection of turbot (Scopthalamus maximus) with the pathogenic ciliate Philasterides dicentrarchi led to the formation of macroscopic intraperitoneal clots in the fish. The clots contained abundant, immobilized ciliates, many of which were lysed. We demonstrated that the plasma clots immobilize and kill the ciliates in vitro. To test the importance of plasma clotting in ciliate killing, we inhibited the process by adding a tetrapeptide known to inhibit fibrinogen/thrombin clotting in mammals. Plasma tended to kill P. dicentrarchi slightly faster when clotting was inhibited by the tetrapeptide, although the total mortality of ciliates was similar. We also found that kaolin, a particulate activator of the intrinsic pathway in mammals, accelerates plasma clotting in turbot. In addition, PMA-stimulated neutrophils, living ciliates and several ciliate components such as cilia, proteases and DNA also displayed procoagulant activity in vitro. Injection of fish with the ciliates generated the massive release of neutrophils to the peritoneal cavity, with formation of large aggregates in those fish with live ciliates in the peritoneum. We observed, by SEM, numerous fibrin-like fibres in the peritoneal exudate, many of which were associated with peritoneal leukocytes and ciliates. Expression of the CD18/CD11b gene, an integrin associated with cell adhesion and the induction of fibrin formation, was upregulated in the peritoneal leukocytes. In conclusion, the findings of the present study show that P. dicentrarchi induces the formation of plasma clots and that the fish coagulation system may play an important role in immobilizing and killing this parasite.

What to Do, and What Not to Do, When Diagnosing and Treating Breakthrough Cancer Pain (BTcP): Expert Opinion

Clinical management of breakthrough cancer pain (BTcP) is still not satisfactory despite the availability of effective pharmacological agents. This is in part linked to the lack of clarity regarding certain essential aspects of BTcP, including terminology, definition, epidemiology and assessment. Other barriers to effective management include a widespread prejudice among doctors and patients concerning the use of opioids, and inadequate assessment of pain severity, resulting in the prescription of ineffective drugs or doses. This review presents an overview of the appropriate and inappropriate actions to take in the diagnosis and treatment of BTcP, as determined by a panel of experts in the field. The ultimate aim is to provide a practical contribution to the unresolved issues in the management of BTcP. Five ‘things to do’ and five ‘things not to do’ in the diagnosis and treatment of BTcP are proposed, and evidence supporting said recommendations are described. It is the duty of all healthcare workers involved in managing cancer patients to be mindful of the possibility of BTcP occurrence and not to underestimate its severity. It is vital that all the necessary steps are carried out to establish an accurate and timely diagnosis, principally by establishing effective communication with the patient, the main information source. It is crucial that BTcP is treated with an effective pharmacological regimen and drug(s), dose and administration route prescribed are designed to suit the particular type of pain and importantly the individual needs of the patient.

Population Fluctuation of Ceratitis capitata (Diptera: Tephritidae) as a Function of Altitude in Eastern Guatemala

Population fluctuations of Ceratitis capitata (Wiedemann) were evaluated over a period of 12 mo in four altitudinal strata (400-750, 750-1,100, 1,100-1,450, and 1,450-1,800 meters above sea level, masl) in Eastern Guatemala. Within each altitudinal range, sampling plots were established in coffee plantations and adjacent areas, in which Jackson traps were set and baited with Trimedlure. Coffee berries and other host fruits were collected. Population density was lowest at the 400-750 masl stratum and highest at 1,450-1,800 masl. At every altitudinal range, the fluctuations of the pest were associated mainly with the availability of ripe coffee berries as a primary host. From 750-1,450 masl, the pest was also associated with the availability of sweet orange and mandarins in commercial and backyard orchards. The highest densities of the pest were recorded in the dry season. Citrus were the main alternate host where ripe coffee berries were not available. This knowledge on population dynamics of C. capitata will contribute to develop more effective area-wide pest management strategies including the use of sterile insects, natural enemies, and bait sprays.

Cultural adaptation and linguistic validation of the Family Decision Making Self Efficacy Scale (FDMSES)

INTRODUCTION

Nurses, following their ethical mandate, collaborate with other health and social professionals or people involved in caring activities. Caregivers in this context are becoming more and more significant for the family or the cared person, who for their stable presence and emotional proximity play a pivotal caring role. To maximize the contribution of caregivers, objective tools that emphasize their skill sets are necessary. The cross-cultural adaptation and validation of the Family Decision Making Self-Efficacy Scale is part of a larger project aimed at understanding the resilience of caregivers in the field of palliative care. Self-efficacy is one of the aspects of personality most closely associated with resilience. Self-efficacy is shown in a specific context, therefore, its study and evaluation of its level, require capabilities that enable individuals perceive themselves as effective in a particular circumstance. The Family Decision Making Self- Efficacy Scale assesses the behavior of caregivers of patients at the end of their life.

METHODS

The Family Decision Making Self-Efficacy Scale was translated (forward and back translation) and was adapted to the Italian clinical cultural setting by a research team that included experts in palliative care, native translators with experience in nursing and experts in nursing. A consensus on the wording of each item in relation to semantic, idiomatic, experiential and conceptual equivalence was sought. The clarity of the wording and the pertinence of the items of the scenario with the conscious patient and with the unconscious patient were evaluated by a group of caregivers who tested the instrument.

RESULTS

The Italian version of the instrument included 12 items for the scenario with the conscious patient and 12 for the scenario with the unconscious patient. The working group expressed consensus on the pretesting version of the instrument. The pre-testing version of the scale was tested on 60 caregivers, 47 taking care of conscious patients and 13 taking care of unconscious patients. In both cases the content of the items was judged relevant and understandable.

CONCLUSIONS

The results for the cross-cultural validation were satisfactory and allowed the application of the instrument in the Italian context.

Transplant tolerance to pancreatic islets is initiated in the graft and sustained in the spleen

The immune system is comprised of several CD4(+) T regulatory (Treg) cell types, of which two, the Foxp3(+) Treg and T regulatory type 1 (Tr1) cells, have frequently been associated with transplant tolerance. However, whether and how these two Treg-cell types synergize to promote allograft tolerance remains unknown. We previously developed a mouse model of allogeneic transplantation in which a specific immunomodulatory treatment leads to transplant tolerance through both Foxp3(+) Treg and Tr1 cells. Here, we show that Foxp3(+) Treg cells exert their regulatory function within the allograft and initiate engraftment locally and in a non-antigen (Ag) specific manner. Whereas CD4(+) CD25(-) T cells, which contain Tr1 cells, act from the spleen and are key to the maintenance of long-term tolerance. Importantly, the role of Foxp3(+) Treg and Tr1 cells is not redundant once they are simultaneously expanded/induced in the same host. Moreover, our data show that long-term tolerance induced by Foxp3(+) Treg-cell transfer is sustained by splenic Tr1 cells and functionally moves from the allograft to the spleen.

High-frequency microwave signal generation using multi-transverse mode VCSELs subject to two-frequency optical injection

In this paper we report a new method of photonic generation of microwave signals using a multi-transverse mode VCSEL subject to two-frequency optical injection. Numerical simulations show that double injection locking involving two transverse modes can be obtained in these systems. We show that the higher-order transverse mode is excited with a much larger amplitude than that of the fundamental transverse mode. The comparison with the case of a single-transverse mode VCSEL subject to similar two-frequency optical injection shows that multi-transverse mode operation of the VCSEL enhances the performance of the photonic microwave generation system. Broad tuning ranges, beyond the THz region, and narrow linewidths are demonstrated in our system. The maximum frequency of the generated microwave signals can be substantially increased if multimode VCSELs are used instead of single-mode VCSELs.

Proteomic analysis of MCF-7 breast cancer cell line exposed to leptin

Background: Obesity is a well-known factor risk for breast cancer in postmenopausal women. Circulating leptin levels are increased in obese and it has been suggested to play an important role in mammary tumor formation and progression. To contribute to the understanding of the molecular mechanisms underlying leptin action in breast cancer, our aim was to identify proteins regulated by leptin in MCF-7 human breast cancer cells. Methods: We used two-dimensional gel electrophoresis (2-DE) and matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) to identify proteins affected by leptin. Results: Thirty proteins were found differentially expressed in MCF-7 cells after 48 h leptin exposure. Proteins regulated by leptin included proteins previously implicated in breast cancer such as catechol-o-methyltransferase, cathepsin D, hsp27, serine/threonine-protein phosphatase and regulatory proteins of the Ras signaling pathway. Proteins involved in other cellular functions such as stress response, cytosqueleton remodeling and proteins belonging to ubiquitin-proteasome system, were also identified. Furthermore, leptin-treated cells showed a substantial uptake of the serum carrier proteins albumin and alpha-2-HS-glycoprotein. Conclusions: This screening reveals that leptin influences the levels of key proteins involved in breast cancer which opens new avenues for the study of the molecular mechanisms linking obesity to breast cancer.

17β-Estradiol regulates oxidative stress in prostate cancer cell lines according to ERalpha/ERbeta ratio

Estrogen action is mediated by the two receptor isoforms: estrogen receptor alpha and beta. Both receptors are expressed in human prostate tissue and have different action profiles. ERalpha is positively correlated with the malignancy of prostate cancer, while ERbeta may protect against abnormal prostate cell growth. 17β-Estradiol (E2), at least in part, induces cancerous transformations by causing deleterious mutations through the formation of reactive oxygen species (ROS). The aim was to study the effect of E2 on oxidative stress and the expression of uncoupling proteins (UCPs) and antioxidant enzymes in several prostate cancer cell lines with different ERalpha/ERbeta ratios. The cell prostate lines with a lower ERalpha/ERbeta ratio had lower oxidative stress, which could be partially explained by the increased expression of antioxidant enzymes and UCPs. Moreover, the action of E2 on the expression of antioxidant enzymes and UCPs was dual and dependent on the ERalpha/ERbeta ratio. Treatments with 0.1 nM E2 in cell lines with high ERalpha/ERbeta ratio produced a decrease in antioxidant enzymes and UCPs levels, with an increase in ROS production. These effects disappeared when the treatment was done in the presence of an ERalpha antagonist (MPP). In the cell lines with greatest levels of ERbeta and the lowest ERalpha/ERbeta ratio, E2 treatment caused the up-regulation of antioxidant enzymes and UCPs with a look-up decrease in ROS production. These effects were reversed when the cells were treated with E2 in the presence of an ERbeta antagonist (R,R-THC). On the whole, our results suggest a dual E2 effect; increasing or decreasing oxidative stress in part by modulation of UCPs and antioxidant enzymes according to the abundance ERbeta and ERalpha/ERbeta ratio in prostate cancer cell lines.

Endoscopic resection as unique treatment for early colorectal cancer

Colonoscopic screening in developed countries allows detection and resection of a great number of early colorectal cancers. There is a strong controversy to decide when endoscopic treatment is enough or when surgical resection is necessary. To this contributes the diverse names to define the lesions, the wide number of classifications and the different criteria of each author. We perform an extense literature review, aiming to clarify concepts and unify criteria that can be used as a guide for the treatment of early colorectal cancer. We conclude that in early colorectal cancer arising in pedunculated polyps (0-Ip), mucosal endoscopic resection would be indicated as only treatment in Haggitt levels 1, 2 and 3, tumors smaller than 2 cm, well- or moderately differentiated, without vascular or lymphatic affection, with submucosal infiltration lower than 1 microm from the muscularis mucosae and maximal submucosal width lower than 4 microm, and undergoing en bloc resection. In sessile polyps (0-Is) or non-polypoideal elevated (0-IIa) or plain (0-IIb) lesions, recommendations will be similar, without applicability of Haggitt levels.

Impaired contractile function and mitochondrial respiratory capacity in response to oxygen deprivation in a rat model of pre-diabetes

AIM

Obesity is a major contributor to the global burden of disease and is closely associated with the development of type 2 diabetes and cardiovascular diseases. This study tested the hypothesis that mitochondrial respiratory capacity of the pre-diabetic heart is decreased leading to impaired contractile function and tolerance to ischaemia/reperfusion.

METHODS

Eight-week-old male Wistar rats were fed a high caloric diet for 16 weeks after which anthropometric, metabolic, cardiac and mitochondrial parameters were evaluated vs. age-matched lean controls. Cardiac function (working heart perfusions) and mitochondrial respiratory capacity were assessed at baseline and in response to acute oxygen deprivation.

RESULTS

Rats fed the high caloric diet exhibited increased body weight and visceral fat vs. the control group. Heart weights of obese rats were also increased. Triglyceride, fasting plasma insulin and free fatty acid levels were elevated, while high-density lipoprotein cholesterol levels were reduced in the obese group. Contractile function was attenuated at baseline and further decreased after subjecting hearts to ischaemia-reperfusion. Myocardial infarct sizes were increased while ADP phosphorylation rates were diminished in obese rats. However, no differences were found for mtDNA levels and the degree of oxidative stress-induced damage.

CONCLUSIONS

These data show that decreased mitochondrial bioenergetic capacity in pre-diabetic rat hearts may impair respiratory capacity and reduce basal contractile function and tolerance to acute oxygen deprivation.

Effects of low electric current (LEC) treatment on pure bacterial cultures

AIMS

This research focused on the effects of low electric current (LEC) on the cell viability and metabolic activity of Escherichia coli and Bacillus cereus.

METHODS AND RESULTS

Different LEC intensities at fixed amperage were applied, employing either graphite or copper electrode pairs, and the effects were determined by conventional cultural methods and bioindicators. On E. coli, the LEC with graphite electrodes at 5 and 10 mA led to no significant variation, but at 20 and 40 mA there was increasing inhibition of both the enzymatic activities and growth, and a reduction in ATP content. On B. cereus, similar experiments at the lower amperages did not have any inhibitor effects, however, the 40 mA current stimulated growth, ATP content and some enzymatic activities. The LEC treatment using copper electrodes caused, already at 5 mA, inhibition of bacterial growth and metabolic and enzymatic activities in both E. coli and B. cereus.

CONCLUSIONS

On the basis of the obtained results using different amperages and electrodes, we can conclude that E. coli seem to be more sensitive compared with B. cereus.

SIGNIFICANCE AND IMPACT OF THE STUDY

The study increases the knowledge on LEC treatment effects on the pure bacterial cultures.

Chronic central administration of apelin-13 over 10 days increases food intake, body weight, locomotor activity and body temperature in C57BL/6 mice

The peptide apelin has been located in a wide range of tissues, including the gastrointestinal tract, stomach and adipose tissue. Apelin and its receptor has also been detected in the arcuate and paraventricular nuclei of the hypothalamus, which are involved in the control of feeding behaviour and energy expenditure. This distribution suggests apelin may play a role in energy homeostasis, but previous attempts to discern the effects of apelin by acute injection into the brain have yielded conflicting results. We examined the effect of a chronic 10-day intracerebroventricular (i.c.v.) infusion of apelin-13 into the third ventricle on food intake, body temperature and locomotor activity in C57BL/6 mice. Apelin-13 (1 microg/day) increased food intake significantly on days 3-7 of infusion; thereafter, food intake of treated and control individuals converged. This convergence was potentially because of progressive conversion of apelin-13 to [Pyr(1)]apelin-13 which has a four-fold lower receptor binding affinity at the orphan G protein-coupled receptor, APJ. Locomotor activity was also higher in the apelin-treated mice, especially during the nocturnal peak, when most feeding occurs, and the first hours of the light phase. Body temperature was also elevated during this increased period of activity, but was otherwise unaffected. Apelin-13-infused animals gained more weight than the saline-infused controls, suggesting the elevated locomotor activity did not offset the increased food intake. Elevated locomotion and the consequent increases in body temperature were probably secondary effects to the increased food intake. These results suggest that apelin-13 may play a central role in the control of feeding behaviour and is one of only two peripheral ligands known to stimulate rather than inhibit intake. As apelin production is elevated during obesity, this may provide an important feed-forward mechanism exacerbating the problem. Antagonists of the apelin receptor may therefore be useful pharmaceuticals in the treatment of obesity.

Gender-dependent differences in serum profiles of insulin and leptin in caloric restricted rats

In the present study, we have investigated whether differences between male and female rats described in response to 40% caloric restriction (CR) were influenced by circulating level variations of sex hormones and/or insulin and leptin. Body weights (BW), organ weights, and adipose depot weights (ADW) were also measured. The most affected tissues by CR were the fat depots. Metabolically active organs were the least affected, especially more in females than in males (male weight lost: 24.3% vs. female: 17.3%). Testosterone and estradiol circulating levels did not show changes by CR. Insulin levels were decreased by CR in both genders, but was more evident in female rats than males. Leptin serum levels were higher in male rats than in females, and CR caused a circulating leptin level reduction only in males. In conclusion, our results indicate that leptin and insulin could be one of the keys of the different hormonal control of energy homeostasis in response to CR between female and male rats. In this sense, leptin serum levels correlated statistically with BW and with individual ADW only in male rats, whereas insulin serum levels correlated statistically with BW and with any of the ADW studied only in females.

Sexual dimorphism in liver mitochondrial oxidative capacity is conserved under caloric restriction conditions

Caloric restriction (CR) without malnutrition has been shown to increase maximal life span and delay the rate of aging in a wide range of species. It has been proposed that reduction in energy expenditure and oxidative damage may explain the life-extending effect of CR. Sex-related differences also have been shown to influence longevity and energy expenditure in many mammalian species. The aim of the present study was to determine the sex-related differences in rat liver mitochondrial machinery, bioenergetics, and oxidative balance in response to short-term CR. Mitochondria were isolated from 6-mo-old male and female Wistar rats fed ad libitum or subjected to 40% CR for 3 mo. Mitochondrial O2 consumption, activities of the oxidative phosphorylation system (complexes I, III, IV, and V), antioxidative activities [MnSOD, glutathione peroxidase (GPx)], mitochondrial DNA and protein content, mitochondrial H2O2 production, and markers of oxidative damage, as well as cytochrome C oxidase and mitochondrial transcription factor A levels, were measured. Female rats showed a higher oxidative capacity and GPx activity than males. This sexual dimorphism was not modified by CR. Restricted rats showed slightly increased oxygen consumption, complex III activity, and GPx antioxidant activity together with lower levels of oxidative damage. In conclusion, the sexual dimorphism in liver mitochondrial oxidative capacity was unaffected by CR, with females showing higher mitochondrial functionality and ROS protection than males.

Nonlinear dynamics of the polarization of multitransverse mode vertical-cavity surface-emitting lasers under current modulation

In this paper we report on a theoretical investigation of the nonlinear dynamics of the polarization of multitransverse mode vertical-cavity surface-emitting lasers (VCSELs) under current modulation. Special attention is given to the comparison with a previously studied case of single-transverse mode VCSEL emitting in two orthogonal polarizations. The consideration of spatial effects in VCSEL modifies the polarization dynamics that accompanies the period doubling route to chaos for large modulation amplitudes. Depending on the modulation parameters, the excitation of a higher order transverse mode may either induce chaotic pulsing in an otherwise regularly pulsating VCSEL, or induce a time-periodic pulsing dynamics in an otherwise chaotic VCSEL. Bifurcation diagrams obtained for different modulation frequencies, several values of the dichroism, and different transverse mode characteristics allow us to identify the different scenarios of polarization dynamics in a directly modulated VCSEL. Temporal analysis of carrier number radial profile reveals considerable changes for the multitransverse mode case only constituting the physical origin of the reported changes in the temporal and polarization dynamics.

Structural and functional characterization of a recombinant sticholysin I (rSt I) from the sea anemone Stichodactyla helianthus

Sticholysins I and II (Sts I and II) are two potent cytolysins from the sea anemone Stichodactyla helianthus. These isoforms present 13 substitutions, with three non-conservative located at the N-terminus. St II is considerably more hemolytic than St I in human red blood cells, a result explained by the smaller number of negatively charged groups present at St II's N-terminus. In the present work, we have obtained a recombinant St I (rSt I), differing from the wild type in a single amino acid residue (E16Q). This pseudo-wild type is structurally similar to St I and shows a similar capacity to interact with and form pores in model membranes. This was assessed by the intrinsic fluorescence increase in the presence of liposomes, their adsorption to bilayers (measured by SPR), their concentration at the air-water interface, their interaction with lipid monolayers and their capacity to promote the release of carboxyfluorescein entrapped in liposomes. In spite of these similarities, rSt I presents a larger hemolytic activity in human red blood cells than St I, being intermediate in activity between Sts I and II. The results obtained in the present work emphasize that even the change of one single E by Q at the N-terminal segment may modify the toxin HA and show that this functional property is the most sensitive to subtle changes in the protein primary structure.

The microbial degradation of azimsulfuron and its effect on the soil bacterial community

AIMS

Azimsulfuron is a recently introduced sulfonylurea herbicide useful in controlling weeds in paddy fields. To date very little information is available on the biodegradation of this pesticide and on its effect on the soil microbial community. The aim of this work was to study its biodegradation both in slurry soil microcosms and in batch tests with mixed and pure cultures.

METHODS AND RESULTS

Azimsulfuron was applied to forest bulk soil in order to study its effect on the structure of the bacterial soil community, as detectable by denaturant gradient gel electrophoresis (DGGE) analyses. Biodegradation and abiotic processes were investigated by HPLC analyses. In addition, a microbial consortium was selected, that was able to use azimsulfuron as the sole energy and carbon source. One of the metabolites produced by the consortium was isolated and identified through LC-MS analyses. Cultivable bacteria of the consortium were isolated and identified by 16S rDNA sequencing (1400 bp).

CONCLUSIONS

Azimsulfuron treatment seems to have the ability to cause changes in the bacterial community structure that are detectable by DGGE analyses. It is easily biodegraded both in microcosms and in batch tests, with the formation of an intermediate that was identified as 2-methyl-4-(2-methyl-2H-tetrazol-5-yl)-2H-pyrazole-3-sulfonamide.

SIGNIFICANCE AND IMPACT OF THE STUDY

The study increases the knowledge on the biodegradation of azimsulfuron and its effects on the soil microbiota.