Functionalized monodisperse microbubble production: microfluidic method for fast, controlled, and automated removal of excess coating material.

Functionalized monodisperse microbubbles have the potential to boost the sensitivity and efficacy of molecular ultrasound imaging and targeted drug delivery using bubbles and ultrasound. Monodisperse bubbles can be produced in a microfluidic flow focusing device. However, their functionalization and sequential use require removal of the excess lipids from the bubble suspension to minimize the use of expensive ligands and to avoid competitive binding and blocking of the receptor molecules. To date, excess lipid removal is performed by centrifugation, which is labor intensive and challenging to automate. More importantly, as we show, the increased hydrostatic pressure during centrifugation can reduce bubble monodispersity. Here, we introduce a novel automated microfluidic 'washing' method. First, bubbles are injected in a microfluidic chamber 1 mm in height where they are left to float against the top wall. Second, lipid-free medium is pumped through the chamber to remove excess lipids while the bubbles remain located at the top wall. Third, the washed bubbles are resuspended and removed from the device into a collection vial. We demonstrate that the present method can (i) reduce the excess lipid concentration by 4 orders of magnitude, (ii) be fully automated, and (iii) be performed in minutes while the size distribution, functionality, and acoustic response of the bubbles remain unaffected. Thus, the presented method is a gateway to the fully automated production of functionalized monodisperse microbubbles.

The effect of renal impairment and obesity on anti-Xa peak and trough levels in patients receiving therapeutic doses of nadroparin: a comparison with control patients.

PURPOSE: Anti-Xa peak level monitoring is recommended during LMWH treatment in renal impairment or obesity. The trough level has been proposed as marker for bleeding. We studied the influence of renal impairment and obesity on anti-Xa levels. METHODS: Peak and trough levels were collected during therapeutic nadroparin treatment in patients with renal impairment, obese patients, and controls. 27 patients (n = 68 samples) were evaluated and combined with published data (n = 319 samples from 35 patients) using population pharmacokinetic (popPK) modelling. RESULTS: Median peak level was 0.44 and 0.95 IU/mL in renal impairment with and without dose reduction and 0.60 and 0.43 IU/mL in obesity and controls, respectively. Trough levels were < 0.5 IU/mL in all patients with renal impairment with dose reduction and in 5/6 control patients. In the popPK model, total body weight and eGFR were covariates for clearance and lean body weight for distribution volume. Model-based evaluations demonstrated peak levels below the therapeutic window in controls and increased levels in renal impairment. Dose reductions resulted in a different effect on peak and trough levels. Obese patients (BMI up to 32 kg/m2) had similar levels upon weight-based dosing. CONCLUSION: In renal impairment, anti-Xa peak levels after dose reduction are comparable to those in controls. Weight-based dosing is suitable for obese patients. Aiming for peak levels between 0.6 and 1.0 IU/mL in these patients would result in overexposure compared to controls. Considering the association of trough levels and bleeding risk and our findings, trough monitoring seems to be a suitable parameter to identify nadroparin accumulation.

Critical appraisal of evidence for anti-Xa monitoring and dosing of low-molecular-weight heparin in renal insufficiency.

INTRODUCTION: Several guidelines advise to monitor therapeutic LMWH therapy with peak anti-Xa concentrations in renal insufficiency with subsequent dose adjustments. A better understanding of the clinical association between peak anti-Xa concentrations and clinical outcomes is mandatory, because misunderstanding this association could lead to erroneous, and potentially even harmful, LMWH dose adjustments. AREAS COVERED: We reviewed the evidence of the widely applied therapeutic window for anti-Xa peak concentrations and report on the evidence for pharmacokinetic dose reduction in renal insufficiency, limitations of peak and trough anti-Xa concentration monitoring. EXPERT OPINION: The added value of peak anti-Xa monitoring in patients with renal insufficiency, receiving a dose reduced for pharmacokinetic changes, is not supported by data. Enoxaparin and nadroparin should be adjusted to 50-65% and 75-85% of the original dose for patients with a creatinine clearance (CrCL) of <30 ml/min and 30-60 ml/min, respectively. Tinzaparin should be adjusted to around 50% of the original dose for patients with a CrCL of <30 ml/min. In case anti-Xa monitoring is applied, trough concentration anti-Xa monitoring is preferred over peak monitoring, aiming at a maximum concentration of 0.4 IU/mL for once-daily dosed tinzaparin and 0.5 IU/mL for twice-daily dosed enoxaparin and nadroparin.

Hypoperfusion Intensity Ratio Correlates with CTA Collateral Status in Large-Vessel Occlusion Acute Ischemic Stroke.

BACKGROUND AND PURPOSE: Collateral blood supply is a key determinant of outcome in large-vessel occlusion acute ischemic stroke. Single- and multiphase CTA collateral scoring systems have been described but are subjective and require training. We aimed to test whether the CTP-derived hypoperfusion intensity ratio is associated with CTA collateral status and whether a threshold hypoperfusion intensity ratio exists that predicts poor CTA collaterals. MATERIALS AND METHODS: Imaging and clinical data of consecutive patients with large-vessel occlusion acute ischemic stroke were retrospectively reviewed. Single-phase CTA and multiphase CTA scoring were performed by 2 blinded neuroradiologists using the Tan, Maas, and Calgary/Menon methods. CTP was processed using RApid processing of PerfusIon and Diffusion software (RAPID). Hypoperfusion intensity ratio = ratio of brain volume with time-to-maximum >10 seconds over time-to-maximum >6-second volume. Correlation between the hypoperfusion intensity ratio and CTA collateral scores was calculated using the Pearson correlation. The optimal threshold of the hypoperfusion intensity ratio for predicting poor collaterals was determined using receiver operating characteristic curve analysis. RESULTS: Fifty-two patients with large-vessel occlusion acute ischemic stroke were included. Multiphase CTA collateral scoring showed better interrater agreement (κ = 0.813) than single-phase CTA (Tan, κ = 0.587; Maas, κ = 0.273). The hypoperfusion intensity ratio correlated with CTA collateral scores (multiphase CTA: r = -0.55; 95% CI, -0.67 to -0.40; P ≤ .001). The optimal threshold for predicting poor multiphase CTA collateral status was a hypoperfusion intensity ratio of >0.45 (sensitivity = 78%; specificity = 76%; area under the curve = 0.86). Patients with high hypoperfusion intensity ratio/poor collateral status had lower ASPECTS/larger infarcts, higher NIHSS scores, and larger hypoperfused volumes. CONCLUSIONS: The hypoperfusion intensity ratio is associated with CTA collateral status in patients with large-vessel occlusion acute ischemic stroke. The hypoperfusion intensity ratio is an automated and quantitative alternative to CTA collateral scoring methods for both clinical and future stroke trial settings.

Chloroquine-induced QTc prolongation in COVID-19 patients.

BACKGROUND: In the battle against the SARS-CoV­2 pandemic, chloroquine has emerged as a new potential therapeutic option for the treatment of infected patients. A safety consideration for the application of chloroquine is its QTc-prolonging potential. Thus far, no data are available on the QTc-prolonging potential of chloroquine in COVID-19 patients. OBJECTIVE: To assess the degree of chloroquine-induced QTc prolongation in hospitalised COVID-19 patients. METHODS: A baseline electrocardiogram (ECG) and ECGs recorded during chloroquine treatment were retrospectively collected in patients suspected of having COVID-19. The QTc interval was calculated by computerised and manual interpretation. Baseline and follow-up QTc intervals were compared using the paired samples t-test. RESULTS: A total of 95 patients had a baseline ECG recording and at least one ECG recording during chloroquine therapy. Chloroquine treatment resulted in a mean QTc prolongation of 35 ms (95% CI 28-43 ms) using computerised interpretation and 34 ms (95% CI 25-43 ms) using manual interpretation. No torsade de pointes was observed during chloroquine treatment. After manual review, 22 patients (23%) had a QTc interval exceeding 500 ms during chloroquine treatment. None of these patients had a prolonged QTc interval prior to the initiation of chloroquine treatment. CONCLUSIONS: Chloroquine significantly prolongs the QTc interval in a clinically relevant matter. This highlights the need for ECG monitoring when prescribing chloroquine to COVID-19 patients.

Multifactorial inhibition of lactobacilli against the respiratory tract pathogen Moraxella catarrhalis.

Probiotics, mainly lactic acid bacteria (LAB), are widely focused on gastrointestinal applications. However, recent microbiome studies indicate that LAB can be endogenous members of other human body sites such as the upper respiratory tract (URT). Interestingly, DNA-based microbiome research suggests an inverse correlation between the presence of LAB and the occurrence of potential pathogens, such as Moraxella catarrhalis, an important URT pathogen linked to otitis media, sinusitis and chronic obstructive pulmonary disease. However, a direct interaction between these microbes has not been explored in detail. This study investigated the direct antipathogenic effects of Lactobacillus species, including several well-documented probiotic strains, on M. catarrhalis using agar-based assays, time course analysis, biofilm assays and minimal inhibitory concentration (MIC) testing. These assays were performed using spent culture supernatans (SCS) at two pHs (4.3 and 7) and D- and/or L-lactic acid at three pHs (2, 4 and 7). In addition, cell line assays for adhesion competition and immunomodulation were used to substantiate the inhibitory effect of lactobacilli against M. catarrhalis. A proportion of Lactobacillus strains, including the model probiotic Lactobacillus rhamnosus GG, showed a strong and direct activity against M. catarrhalis. Screening of the activity of the SCS after different treatments demonstrated that lactic acid has an important antimicrobial activity against this pathogen - at least in vitro - with mean MIC values for D- and L-lactic acid varying between 0.5 and 27 g/l depending on the pH. Furthermore, L. rhamnosus GG also decreased the adhesion of M. catarrhalis to human airway epithelial Calu-3 cells with more than 50%, and the expression of mucin MUC5AC, pro-inflammatory cytokines interleukin (IL)-8, IL-1ß, and tumor necrosis factor-α at least 1.2 fold. This study suggests that several lactobacilli and their key metabolite lactic acid are possible candidates for probiotic therapeutic interventions against URT infections.

Use of oral immunosuppressive drugs in the treatment of atopic dermatitis in the Netherlands.

BACKGROUND: Although atopic dermatitis (AD) is a very common skin disease, data on the percentage of patients with really difficult-to-treat AD are scarce. From socio-economic perspective, it is important to have more insight into these numbers, as new very effective, but expensive, treatment options will be available in the near future for difficult-to-treat AD. Estimating the number of patients with AD using oral immunosuppressive drugs can give an impression of the percentage of difficult-to-treat patients in the total AD population. OBJECTIVE: To give an overview of the use of oral immunosuppressive drugs in patients with AD in the Netherlands. METHODS: Prescription data of oral immunosuppressive drugs in the Netherlands were extracted from a pharmaceutical database (NControl) containing data of 557 million prescriptions and 7.2 million patients. An algorithm, based on the WHO Anatomical Therapeutic Chemical (ATC) codes, was used to identify patients with AD. The prescription of oral immunosuppressive drugs in patients with AD between 1 January 2012 and 1 January 2017 was evaluated. RESULTS: Based on the algorithm, 65 943 patients with AD were selected. 943 patients with AD (1.4%) used cyclosporine A, methotrexate, azathioprine or mycophenolic acid. Methotrexate was most commonly used, followed by azathioprine and cyclosporine A. A switch in medication was rarely seen. In the evaluation period, a decrease in the prescription of cyclosporine A was seen, together with an increase in the prescription of methotrexate. In 31% of the patients who stopped treatment, the discontinuation took place within the first months of treatment. CONCLUSION: In this study population, 1.4% of the patients with AD used oral immunosuppressive drugs for their eczema in a 5-year period. Methotrexate was the most commonly used systemic drug in the Netherlands for the treatment of AD.

Thiopurine metabolite levels in patients with atopic dermatitis and/or chronic hand/foot eczema treated with azathioprine.

BACKGROUND: Azathioprine is frequently used in severe eczema. It is converted in the liver into active metabolites, including 6-thioguanine nucleotide (6-TGN) and methylated 6-methylmercaptopurine (6-MMP). In the past, the therapeutic potential of azathioprine may have not been fully utilized. Recent investigations on inflammatory bowel disease have led to a better understanding of azathioprine metabolism and optimizing treatment. OBJECTIVE: To investigate whether measuring thiopurine metabolites in circulation can improve the effectiveness and safety of azathioprine treatment in patients with atopic dermatitis and/or chronic hand/foot eczema. METHODS: Azathioprine metabolite levels were measured in eczema patients during maintenance treatment (Part I) and dose escalation (Part II). Clinical effectiveness, hepatotoxicity, and bone marrow suppression were analyzed and TPMT genotype was assessed. RESULTS: A wide variation in metabolite levels in all dose groups was observed. In Part I (32 patients), there were no significant differences in 6-TGN levels between clinical responders and non-responders (p = .806). No hepatoxicity or myelotoxicity was observed. In Part II, all 6-TGN and 6-MMP levels increased during dose escalation. Hypermethylation was observed in 2/8 patients. CONCLUSION: For individual eczema patients treated with azathioprine, routinely measuring 6-TGN and 6-MMP can be helpful in optimizing azathioprine dose, improving clinical effectiveness, and preventing side effects.

Reverse shoulder arthroplasty in young patient with achondroplasia - Ten year follow up: Case report.

Skeletal dysplasia in achondroplasia can affect all body joints - including the glenohumeral joint - and is prone to develop to degenerative osteoarthritis (OA). This may cause pain and mobility problems at young age. Surgical treatment is challenging due to the dysplastic anatomy of the shoulder joint - with a dysplastic deformed short humerus, a small, hypoplastic medialized glenoid and lateralized acromion - and the long life expectancy of these patients. The indications for reverse shoulder arthroplasty (RSA) evolved during years with rotator cuff tears and rotator cuff arthropathy in combination with or without glenohumeral OA as the main indicator, with good short to mid-term results. Long term results of RSA are rarely found in literature, especially in young patients. The use of a RSA in glenohumeral OA with an intact rotator cuff has rarely been reported. In this case report we present the ten-year clinical and radiographic results of a RSA for the treatment of degenerative OA with glenohumeral dysplasia in a young patient with achondroplasia.

Paediatric fractures around the knee.

Paediatric fractures around the knee are not common but their incidence seems to be increasing as a result of the increasing number of children participating in sports. Given the characteristics of the growing skeleton, specific fractures only occur in children. Diagnosis is mainly based on history, clinical examination and plain radiographs. Advanced imaging may be required in special fracture types. Although many of these injuries can be managed non-operatively, early referral to a specialist team is necessary to avoid delays in surgical management and to reduce the risk of acute or late complications.

Efficacy and safety of collagenase treatment for Dupuytren's disease: 2-year follow-up results.

Dupuytren's contracture is a common hand problem that affects the palmar fascia. Several treatment options exist, but none are curative and recurrence is common. Bacterial collagenase has recently been proven beneficial for treating Dupuytren's disease, cleaving the collagen fibers at different sites, with weakening and eventually rupture of the fibrous cords after manipulation. An independent prospective follow-up study was organized on 87 patients, treated with one or more collagenase injections. Inclusion criteria were a contracture of at least 20° at the metacarpophalangeal (MCP) or the proximal interphalangeal (PIP) joint. The most diseased joint was taken into consideration for follow-up evaluation. The resulting extension deficit was measured at 1 month, 1 year and 2 years and was graded as "clinical success", "clinical improvement" or "clinical failure". The mean contracture improved from 45° (39° for MCP and 54° for PIP joints) before treatment to 5° (2° for MCP and 9° for PIP joints) 4 weeks after treatment. No serious complications occurred. After 2 years, 68 joints were evaluated; 61.5% of the MCP joints and 34.5% of the PIP joints had a contracture of ≤20°. When compared with the 4-week evaluation, 28.2% of MCP joints and 62.1% of PIP joints had a recurrence (20° or greater worsening) or had received additional treatment. Collagenase injection is a safe and effective treatment option for Dupuytren disease, but recurrence is common especially for the PIP joint.

Effect of an antibiotic checklist on length of hospital stay and appropriate antibiotic use in adult patients treated with intravenous antibiotics: a stepped wedge cluster randomized trial.

OBJECTIVES: Quality indicators (QIs) have been developed to define appropriate antibiotic use in hospitalized patients. We evaluated whether a checklist based on these QIs affects appropriate antibiotic use and length of hospital stay. METHODS: An antibiotic checklist for patients treated with intravenous antibiotics was introduced in nine Dutch hospitals in a stepped wedge cluster randomized trial. Prophylaxis was excluded. We included a random sample before (baseline), and all eligible patients after (intervention) checklist introduction. Baseline and intervention outcomes were compared. Primary endpoint was length of stay (LOS), analysed by intention to treat. Secondary endpoints, including QI performances, QI sum score (performance on all QIs per patient), and quality of checklist use, were analysed per protocol. RESULTS: Between 1 November 2014 and 1 October 2015 we included 853 baseline and 5354 intervention patients, of whom 993 (19%) had a completed checklist. The LOS did not change (baseline geometric mean 10.0 days (95% CI 8.6-11.5) versus intervention 10.1 days (95% CI 8.9-11.5), p 0.8). QI performances increased between +3.0% and +23.9% per QI, and the percentage of patients with a QI sum score above 50% increased significantly (OR 2.4 (95% CI 2.0-3.0), p<0.001). Higher QI sum scores were significantly associated with shorter LOS. Discordance existed between checklist-answers and actual performance. CONCLUSIONS: Use of an antibiotic checklist resulted in a significant increase in appropriateness of antibiotic use, but not in a reduction of LOS. Low overall checklist completion rates and discordance between checklist-answers and actual provided care might have attenuated the impact of the checklist.

Predicting therapy response to mycophenolic acid using UGT1A9 genotyping: towards personalized medicine in atopic dermatitis.

Atopic dermatitis (AD) is a very common chronic inflammatory skin disease requiring long-term treatment. Mycophenolic acid (MPA) is used off-label in treatment of patients with severe AD failing Cyclosporin A (CsA) treatment, however clinical efficacy is observed in only half of the AD patients. In blood, MPA levels are known to have a large interindividual variability. Low MPA exposure and increased enzyme activity correlates with the presence of UGT1A9 polymorphisms. In this retrospective study, 65 adult AD patients treated with MPA were classified as responder or non-responder to MPA treatment. UGT1A9 polymorphisms were determined using PCR. A significantly higher number of UGT1A9 polymorphisms was found in the group that did not respond to MPA treatment. Of the patients that carried a UGT1A9 polymorphism, 85.7% were non-responsive to MPA treatment. This implies that non-responsiveness in AD patients is more likely to occur in carriers of a UGT1A9 polymorphism. In a binary logistic regression analysis the odds ratio (OR) was 8.65 (95% confidence interval: 0.93-80.17). Our results show that UGT1A9 polymorphisms can be used to identify patients with non-responsiveness to MPA. Patients with UGT1A9 polymorphisms might benefit from higher MPA dosage.

Case Report: SPECT/CT as the New Diagnostic Tool for Specific Wrist Pathology.

Introduction: Single photon emission computed tomography has been introduced as a promising new diagnostic tool in orthopaedic pathology since the early 90'. Computed tomography, the combined with SPECT, gives insight in the specific sight of wrist pathology. Literature already supports introduction of SPECT/CT in wrist pathology, but clinical application is lagging. Case Report: A 40yr old patient reported first in 2004 with persisting pain after a right distal radius fracture. Several diagnostics and operative interventions were performed, all unsuccessful. Because of the persisting pain a SPECT-CT was performed which showed a cyst in the hamate bone, which was successfully enucleated. The patient was finally pain free at recent follow-up. With a QDash-score of 43 and a PRW (H) E-DLV-score of 58/150. Discussion: In this case report, SPECT/CT proved a very sensitive diagnostic tool for specific pathology of the wrist. It offered precise localisation and thereby the clinically suspected diagnosis was confirmed and the patient successfully treated.

[Successful amantadine treatment of a patient with ECT-resistant catatonia]. / Succesvolle behandeling met amantadine bij een patiënt met ECT-resistente maligne katatonie.

Catatonia is a common neuropsychiatric syndrome. There is a life-threatening subtype of this disease known as malignant catatonia. One of the hypotheses regarding the pathogenesis is an imbalance of multiple neurotransmitters (gaba, glutamate and dopamine). The first step in treatment is to administer benzodiazepines; if the response is insufficient, the treatment can be replaced by electroconvulsive therapy (ect). So far, there is no consensus with regard to the tertiary treatment step. On the basis of a case report we describe the beneficial effects of administering an nmda receptor antagonist, amantadine, as the tertiary step for treating a patient with treatment-resistant malignant catatonia.

Epidemiology, pathophysiology and putative genetic basis of carbamazepine- and oxcarbazepine-induced hyponatremia.

The use of carbamazepine (CBZ) and oxcarbazepine (OXC) as first-line antiepileptic drugs in the treatment of focal epilepsy is limited by hyponatremia, a known adverse effect. Hyponatremia occurs in up to half of people taking CBZ or OXC and, although often assumed to be asymptomatic, it can lead to symptoms ranging from unsteadiness and mild confusion to seizures and coma. Hyponatremia is probably due to the antidiuretic properties of CBZ and OXC that are, at least partly, explained by stimulation of the vasopressin 2 receptor/aquaporin 2 pathway. No known genetic risk variants for CBZ- and OXC-induced hyponatremia exist, but likely candidate genes are part of the vasopressin water reabsorption pathway.

A Peculiar Case of a Floating Angio-Seal.

PURPOSE: To show a complication of the use of an Angio-Seal™ closure device. CASE: We present a patient with a systolic murmur in his femoral artery after PCI. The murmur was caused by a dislocated Angio-Seal™, a vascular closure device. This was diagnosed by Doppler Ultrasound. The device was surgically removed. CONCLUSION: Vascular complications, such as lower limb ischemia, requiring surgical intervention tend to be higher after use of a vascular closure device. We advise routine physical examination of the puncture site after percutaneous closure with a vascular closure device, such as an Angio-Seal™. The removal of the device can be performed via an open or endoscopic approach, based on available experience.