Interplay between inter- and intraparticle interactions in bi-magnetic core/shell nanoparticles

The synthesis strategy and magnetic characterisation of two systems consisting of nanoparticles with core/shell morphology are presented: an assembly of hard/soft nanoparticles with cores consisting of magnetically hard cobalt ferrite covered by a magnetically soft nickel ferrite shell, and the inverse system of almost the same size and shape. We have successfully designed these nanoparticle systems by gradually varying the magnetic anisotropy resulting in this way in the modulation of the magnetic dipolar interactions between particles. Both nanoparticle systems exhibit high saturation magnetisation and display superparamagnetic behaviour at room temperature. We have shown strong exchange coupling at the core/shell interface of these nanoparticles systems which was also confirmed by mesoscopic modelling. Our results demonstrate the possibility of modulating magnetic anisotropy not only by chemical composition but also by adopting the proper nano-architecture.

COVID-19-associated mucormycosis presenting to the Emergency Department-an observational study of 70 patients

BACKGROUND

Mucormycosis (MM) is a deadly opportunistic fungal infection and a large surge in COVID-19-associated mucormycosis (CAM) is occurring in India.

AIM

Our aim was to delineate the clinico-epidemiological profile and identify risk factors of CAM patients presenting to the Emergency Department (ED).

DESIGN

This was a retrospective, single-centre, observational study.

METHODS

We included patients who presented with clinical features or diagnosed MM and who were previously treated for COVID-19 in last 3 months of presentation (recent COVID-19) or currently being treated for COVID-19 (active COVID-19). Information regarding clinical features of CAM, possible risk factors, examination findings, diagnostic workup including imaging and treatment details were collected.

RESULTS

Seventy CAM patients (median age: 44.5 years, 60% males) with active (75.7%) or recent COVID-19 (24.3%) who presented to the ED in between 6 May 2021 and 1 June 2021, were included. A median duration of 20 days (interquartile range: 13.5-25) was present between the onset of COVID-19 symptoms and the onset of CAM symptoms. Ninety-three percent patients had at least one risk factor. Most common risk factors were diabetes mellitus (70%) and steroid use for COVID-19 disease (70%). After clinical, microbiological and radiological workup, final diagnosis of rhino-orbital CAM was made in most patients (68.6%). Systemic antifungals were started in the ED and urgent surgical debridement was planned.

CONCLUSION

COVID-19 infection along with its medical management have increased patient susceptibility to MM.

Postprandial endothelial dysfunction and CIMT after oral fat challenge in patients with type 2 diabetes mellitus with and without macrovascular disease - A preliminary study

BACKGROUND

Very few studies have reported on association of postprandial lipids and endothelial dysfunction among patients with diabetes. Whether endothelial dysfunction particularly postprandial FMD is worse in patients with T2DM with macrovascular disease compared to those without and whether this difference is related to postprandial hypertriglyceridemia (PPHTg) is unclear. Therefore, present study was aimed to assess the relationship between PPHTg and endothelial function in patients with T2DM with and without macrovascular disease.

METHOD

Endothelial dysfunction by FMD and CIMT were compared in patients with T2DM with and without macrovascular disease (n = 13 each group) and 13 age, sex and BMI matched healthy individuals after an oral fat challenge.

RESULTS

There was significant postprandial deterioration of FMD 4-hr after fat challenge in patients with diabetes (P < 0.001) as well as healthy individuals (P = 0.004). Patients with diabetes with macrovascular disease had significantly lower fasting (5.7 ± 6.1% vs. 22.7 ± 10.0% and vs. 24.7 ± 5.3%) as well as postprandial (4-hr) (3.1 ± 5.0% vs. 15.3 ± 8.1% and vs. 15.4 ± 5.7%) FMD compared to other two groups. Fasting, postprandial as well as change in FMD and CIMT in patients with diabetes correlated significantly with fasting as well as postprandial triglycerides with stronger correlation in those with macrovascular disease.

CONCLUSION

Study found significant endothelial dysfunction by FMD that shows substantial further deterioration postprandially following high fat meal in patients with diabetes with macrovascular disease compared to patients with diabetes without macrovascular disease and healthy individuals. Study also indicates that PPHTg is a contributor to endothelial dysfunction. However, more studies are required to corroborate these findings.

Echocardiographic global longitudinal strain as a marker of myocardial fibrosis predicts outcomes in aortic stenosis

Background

Left ventricular global longitudinal strain (LV-GLS) by speckle tracking echocardiography (STE) reflects intrinsic myocardial function, influenced by interstitial abnormalities. Cardiovascular magnetic resonance (CMR) detects myocardial fibrosis non-invasively, but it is limited for widespread use. We aim to establish LV-GLS as a marker of replacement myocardial fibrosis on CMR and validate the prognostic value of LV-GLS thresholds associated with fibrosis.

Methods

LV-GLS thresholds of replacement fibrosis were established in the derivation cohort: 151 patients (57±10 years; 58% males) with hypertension who underwent STE to measure LV-GLS and CMR for replacement myocardial fibrosis. Prognostic value of the thresholds was validated in a separate outcome cohort: 261 patients with moderate-severe aortic stenosis (AS; 71±12 years; 58% males; NYHA functional class I-II) and preserved LVEF ≥50%. Primary outcome was a composite of cardiovascular mortality, heart failure hospitalization, myocardial infarction and cerebrovascular events.

Results

In the derivation cohort, LV-GLS demonstrated good discrimination (c-statistics 0.74; 95% confidence interval: 0.66–0.83; P&lt;0.001) and calibration (Hosmer-Lemeshow X2=6.37; P=0.605) for replacement fibrosis. In the outcome cohort, 52 events occurred over 16 [3.1, 42.0] months of follow-up. Patients with LV-GLS &gt;−15.0% (corresponding to 95% specificity to rule-in myocardial fibrosis) had the worst outcomes compared to patients with LV-GLS &lt;−21.0% (corresponding to 95% sensitivity to rule-out myocardial fibrosis) and those between −21.0 and −15.0% (log-rank P&lt;0.001; Figure 1). Furthermore, LV-GLS offered independent prognostic value over clinical variables, AS severity, echocardiographic LVEF and E/e' (hazard ratio 1.18; 95% confidence interval: 1.07 to 1.30; P=0.001).

Conclusions

LV-GLS thresholds associated with replacement myocardial fibrosis is a novel approach to risk-stratify patients with AS and preserved LVEF (Figure 2).

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Medical Research Council Figure 1Figure 2

Monitoring SARS-CoV-2 decontamination by dry heat and ultraviolet treatment with a swine coronavirus as a surrogate

The critical need for reliable methods to validate decontamination protocols for personal protective equipment (PPE) for re-use during the SARS-CoV-2 pandemic is limited by the need for specialized containment facilities to handle the virus. Hence, we have herein validated the use of a swine coronavirus as a surrogate, and tested the effectiveness of dry heat and ultraviolet (UV) rays for PPE decontamination. Exposure of experimentally contaminated N95 masks and hospital gowns to 60°C for 20 min, and UVC at 1800 mJ/cm² resulted in a 4-log reduction and inactivation of the surrogate virus. This study provides a novel alternative to validate PPE reprocessing methods.

Utility of silent magnetic resonance angiography in the evaluation and characterisation of intracranial dural arteriovenous fistula

AIM

To evaluate the utility of silent magnetic resonance angiography (MRA) in the diagnosis, characterisation, and therapeutic planning of intracranial dural arteriovenous fistula (DAVF).

MATERIALS AND METHODS

Twenty consecutive patients with DAVF were enrolled prospectively and were evaluated using silent MRA and digital subtraction angiography (DSA) as a part of routine work-up. The diagnosis and location of fistula, Borden and Cognard classification, entire arterial feeders, and venous drainage were analysed. A therapeutic strategy was formulated, and the accessible route and vessel were predicted, which was confirmed on endovascular treatment.

RESULTS

Silent MRA was 100% sensitive and accurate for location and classification of fistulas. Silent MRA showed a sensitivity of 82% and 76.5% for entire arterial feeders and draining veins, which improved to a sensitivity of 90% and 94% when prominent feeders and immediate venous drainage was considered. Among the missed veins, thrombosed sinus, slow sinus flow, small calibre, reduced image quality were the causes. The therapeutic decision matched with DSA in all cases and silent MRA accurately identified the potential accessible feeder in 94% cases.

CONCLUSION

Silent MRA is a promising MR technique that can provide both diagnostic and therapeutic information similar to that obtained from DSA.

Severe dissecting scalp cellulitis successfully treated with serial excisions in combination with anti-TNF therapy

The management of dissecting scalp cellulitis involves medical treatment with oral antibiotics and isotretinoin, as well as surgical input in more severe cases. In extensive disease, a full scalpectomy with reconstruction can be required. We report a case of severe dissecting scalp cellulitis in a 34-year-old man who underwent serial scalp excisions over three years, with wounds being left to heal by secondary intention. Initially, the excisions helped to control symptoms but, once the patient was on concurrent anti-TNF therapy, further excisions were successful in reducing disease load and inducing remission. He remained disease free at the 20 months follow-up. This case is the first of its kind to be described in the literature and it highlights how a conservative, staged surgical approach, in combination with anti-TNF therapy, can be effective in the management of severe dissecting scalp cellulitis. In doing so, it offers an alternative to full scalpectomy with reconstruction.

POS1143 GOUT AND JOINT REPLACEMENTS IN THE US

Background:

Irreversible joint damage in gout has been linked to a possible increase in knee and hip joint replacements1. In addition, the strong association between gout and osteoarthritis2,3 could also lead to an increased risk of joint replacements in patients with gout. Population-based data from the UK and Taiwan have shown hazard rates of 1.14 and 1.16 respectively for knee replacements in patients with gout compared to age and gender matched controls1. However, there is little national data in the US on clinical and economic burden of joint replacements in patients with gout.

Objectives:

To evaluate total or partial hip and knee joint replacements in patients with gout in the US and to estimate their economic impact

Methods:

The Nationwide Inpatient Sample (NIS) is a stratified random sample of all US community hospitals. It is the only US national hospital database with information on all patients, regardless of payer, including persons covered by Medicare, Medicaid, private insurance, and the uninsured. Detailed information including clinical and nonclinical data elements on each hospital stay including International Classification of Diseases (ICD)10 diagnosis and procedure codes, age, gender, length of stay, payer, charges, comorbidities etc. is available. We examined hospitalizations in patients with gout with hip and knee joint replacements in NIS 2018, the most recent year of data.

Results:

In 2018, there were 914,510 hospitalizations with primary or secondary diagnosis of gout in the US. Of these 43,615 were for joint replacement surgeries (knee (24,840) and hip (18,755)). Patients with knee replacement were on an average 68.5 years old (95% confidence intervals 68.2 years -68.8 years). Patients with hip replacement were slightly older (mean age 70.3 years, 95% confidence intervals 69.8 years -70.7 years). Unlike general population statistics, men formed a majority of these joint replacements (68% for the knee and 72% for the hip). The average charge per hospitalization was $69,279 and $72,944 for knee and hip replacement respectively. The total annual national cost estimate was $3.09 billion, with government insurances (Medicare and Medicaid) responsible for 67% of knee replacement and 70% of hip replacement costs.

Conclusion:

Joint replacements in gout patients have a large clinical and economic burden in the US. This calls for an increased awareness and management of associated hip and knee arthritis in patients with gout.

References:

[1]Kuo CF, Chou IJ, See LC, et al. Urate-lowering treatment and risk of total joint replacement in patients with gout. Rheumatology. Dec 1 2018;57(12):2129-2139.

[2]Howard RG, Samuels J, Gyftopoulos S, et al. Presence of gout is associated with increased prevalence and severity of knee osteoarthritis among older men: results of a pilot study. Journal of clinical rheumatology: practical reports on rheumatic & musculoskeletal diseases. Mar 2015;21(2):63-71.

[3]Roddy E, Zhang W, Doherty M. Are joints affected by gout also affected by osteoarthritis? Annals of the rheumatic diseases. Oct 2007;66(10):1374-1377.

Disclosure of Interests:

Gurkirpal Singh Shareholder of: Pfizer, Merck, Sanofi, Grant/research support from: Horizon, Maanek Sehgal: None declared, Alka Mithal: None declared.

On the detection of surface spin freezing in iron oxide nanoparticles and its long-term evolution under ambient oxidation

Exchange bias (EB) effects linked to surface spin freezing (SSF) are commonly found in iron oxide nanoparticles, while signatures of SSF in low-field temperature-dependent magnetization curves have been much less frequently reported. Here, we present magnetic properties of dense assemblies of similar-sized (∼8 nm diameter) particles synthesized by a magnetite (sample S1) and a maghemite (sample S2) method, and the influence of long-term (4 year) sample aging under ambient conditions on these properties. The size of the EB field of the different sample (fresh or aged) states is found to correlate with (a) whether a low-temperature hump feature signaling the SSF transition is detected in out-of-phase ac susceptibility or zero-field-cooled (ZFC) dc magnetization recorded at low field and with (b) the prominence of irreversibility between FC and ZFC curves recorded at high field. Sample S1 displays a lower magnetization than S2, and it is in S1 where the largest SSF effects are found. These effects are significantly weakened by aging but remain larger than the SSF effects in S2, where the influence of aging is considerably smaller. A non-saturating component due to spin disorder in S1 also weakens with aging, accompanied by, we infer, an increase in the superspin and the radius of the ordered nanoparticle cores. X-ray diffraction and Mössbauer spectroscopy provide indication of maghemite-like stoichiometry in both aged samples as well as thicker disordered particle shells in aged-S1 relative to aged-S2 (crystallographically-disordered and spin-disordered according to diffraction and Mössbauer, respectively). The pronounced diminution in SSF effects with aging in S1 is attributed to a (long-term) transition, caused by ambient oxidation, from magnetite-like to maghemite-like stoichiometry, and a concomitant softening of the spin-disordered shell anisotropy. We assess the impact of this anisotropy on the nature of the blocking of the nanoparticle superspins.

Serine-glycine-betaine, a novel dipeptide from an endophyte Macrophomina phaseolina: isolation, bioactivity and biosynthesis

AIMS

Endophytes are a rich source for structurally complex chemical scaffolds with interesting biological activities. Endophytes associated with Brugmansia aurea L. (family: Solanaceae), a medicinal plant, have not yet explored for the bioactive metabolites.

METHOD AND RESULTS

Hence, Macrophomina phaseolina, a fungal endophyte, was isolated from the roots of the plant. Its methanolic extract was found active against human cancer cell lines with IC₅₀ <20 µg ml^-1 . Later, a di-peptide compound, serine-glycine-betaine, was isolated and characterized. Serine-glycine-betaine consists of a unit of an N-trimethyl glycine attached to serine. It exhibited potent activity against MIA PaCa-2 and HCT-116 cell lines with IC₅₀ 8·9 and 15·16 μmol l^-1 , respectively. Furthermore, it induced apoptosis in MIA PaCa-2 cells confirmed by microscopy. The apoptotic cell death in MIA PaCa-2 cells was evidenced biochemically with the generation of intracellular reactive oxygen species level and leading to loss of mitochondrial membrane potential due to activation of the intrinsic pathway. This study describes the plausible biosynthesis of serine-glycine-betaine based on genomics (genome sequencing, annotation and genes alignment).

CONCLUSIONS

A novel di-peptide, serine-glycine-betaine isolated from M. phaseolina induced apoptosis in MIA-Pa-Ca-2 cells.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study confirms that dipeptides like serine-glycine-betaine and tyrosine-betaine might be specific to fungal genera, hence being used for diagnostic purposes.

Erratum to "Fragmentation dynamics of single agglomerate-to-wall impaction" [Powder Technology 378 (2021) 561-575, DOI: 10.1016/j.powtec.2020.10.021]

[This corrects the article PMC8724865.].