Cluster‐based permutation tests of MEG/EEG data do not establish significance of effect latency or location

Cluster‐based permutation tests are gaining an almost universal acceptance as inferential procedures in cognitive neuroscience. They elegantly handle the multiple comparisons problem in high‐dimensional magnetoencephalographic and EEG data. Unfortunately, the power of this procedure comes hand in hand with the allure for unwarranted interpretations of the inferential output, the most prominent of which is the overestimation of the temporal, spatial, and frequency precision of statistical claims. This leads researchers to statements about the onset or offset of a certain effect that is not supported by the permutation test. In this article, we outline problems and common pitfalls of using and interpreting cluster‐based permutation tests. We illustrate these with simulated data in order to promote a more intuitive understanding of the method. We hope that raising awareness about these issues will be beneficial to common scientific practices, while at the same time increasing the popularity of cluster‐based permutation procedures.     

In Vitro and In Vivo Biocompatibility of Novel Zwitterionic Poly(Beta Amino)Ester Hydrogels Based on Diacrylate and Glycine for Site‐Specific Controlled Drug Release

New (β‐aminoester) hydrogels (PBAE) based on di(ethylene glycol)diacrylate and glycine are successfully synthesized and characterized for the first time in this work. PBAE macromers are obtained using Michael addition. By changing the diacrylate/amine stoichiometric ratio, but maintaining it >1, samples with different chemical structure containing acrylate end‐groups are obtained. The hydrogels are synthesized from macromers utilizing free radical polymerization. Chemical structure of macromers and hydrogels is confirmed by proton nuclear magnetic resonance, and Fourier transform infra‐red spectroscopy. Swelling and degradation rates in physiological pH range change notably with pH and monomer molar ratio, validating pH sensitivity and zwitterionic behavior, which can be finely tuned by changing any of these parameters. In vitro cytotoxicity and in vivo acute embryotoxicity in zebrafish (Danio rerio) performed to assess the biocompatibility of the novel hydrogel materials and their degradation products reveal that materials are nontoxic and biocompatible. The Cephalexin in vitro drug release study, at pH values 2.20, 5.50, and 7.40, demonstrates pH‐sensitive delivery with the release profiles effectively controlled by pH and the hydrogel composition. PBAE hydrogels exhibit great potential for a variety of biomedical applications, including tissue regeneration and intelligent drug delivery systems.     

Coronary thrombi neovascularization in patients with ST-elevation myocardial infarction - clinical and angiographic implications

Introduction

Coronary artery thrombosis in ST-elevation myocardial infarction (STEMI) is a dynamic process often preceded by episodes of silent plaque rupture and subocclusive thrombosis. Thrombus organization is achieved by ingrowth of endothelial and smooth muscle cells. Clinical significance and impact of thrombus neovascularization on primary percutaneous coronary intervention (pPCI) outcome remain unclear. Therefore we investigated composition and neovascularization of thrombi aspirated during pPCI and their association with clinical and angiographic parameters of STEMI patients.

Methods

Aspirated thrombi retrieved from 84 STEMI patients were classified as fresh (< 1 day), lytic (1-5 days) or organized (> 5 days). Thrombus neovascularization was evaluated immunohistochemically using CD34, CD31 and VEGF antibodies. CD34 and CD31 immunopositive (CD34/CD31 +) cells were organized as single, clusters and microvessels. VEGF positivity was graded as low or high, based on thrombus surface immunopositive area.

Results

CD34/CD31 + cells were present in 67% of all aspirated thrombi. Thrombus CD34/CD31 positivity was associated with previous history of angina pectoris (χ² = 6.142, p = 0.013) and lower myocardial blush grade (MBG < 3, χ² = 12.602, p < 0.001). Organization of CD34/CD31 + cells showed inverse association with the extent of VEGF positivity (χ² = 10.607, p = 0.005). Fresh thrombi were associated with shorter ischemic time (U = 237.5, p = 0.002) and MBG 3 (χ² = 6.379, p = 0.012).

Conclusions

Older thrombus age and neovascularization are associated with suboptimal myocardial perfusion in STEMI patients. Thrombus VEGF expression is inversely associated with degree of CD34 + cell organization. Therefore, neovascularization of aspirated thrombi may indicate the duration of thrombosis, coronary microcirculation status and outcome in STEMI patients.     

Non-Invasive Liver Ablation Using Histotripsy: Preclinical Safety Study in an In Vivo Porcine Model

This study investigates the safety profile for use of histotripsy, a non-invasive ultrasonic ablation method currently being developed for the treatment of liver cancer, for liver ablation in an in vivo porcine model. Histotripsy treatments were applied to the liver and hepatic veins of 22 porcine subjects, with half of the subjects receiving systemic heparinization. Vital signs (heart rate, blood pressure, temperature, electrocardiogram and SpO₂) were monitored throughout the procedure and for 1 h post-treatment. Blood was drawn at six points during the experiment to analyze blood gases, liver function and free hemoglobin levels. All treatments were guided and monitored by real-time ultrasound imaging. After treatment, the tissue was harvested for histological analysis. Results indicated that histotripsy generated well-defined lesions inside the liver and around the treated hepatic veins of all subjects in both treatment groups. Vital signs and blood analysis revealed that animals responded well to histotripsy, with all animals surviving the treatment. One animal in the non-heparinized group had a transient increase in pH and decreases in blood pressure, heart rate and PCO₂ during the 15-min vessel treatment, with these changes returning to baseline levels soon after the treatment. Overall, the results indicate that histotripsy can safely be performed on the liver without the need for systemic heparinization, even in regions containing large hepatic vessels, supporting its future use for the treatment of liver cancer.     

The Status of Nursing Documentation in Slovenia: a Survey

Health documentation is a prerequisite for good and sustainable health and social care. It is especially important for patient involvement and their empowerment. A transition from paper to e-documentation together with the electronic patient record should be based on thorough knowledge of the current state of documentation and its usages. The main objective of this paper was to analyse which documents and work methods of documenting processes within nursing are being used within different environments. Furthermore, what are the main reasons for their discrepancies from theoretical approaches and best practices. The analysis is based on a survey carried out on all three levels of healthcare. The survey questionnaire consisted of 12 questions to which responded 286 nursing teams from community health centres, hospitals and retirement homes in Slovenia. The results point to diversity in documenting as well as lack of interoperability. This is reflected in a great number of different documents. All phases of the nursing process were being documented in only 31.8 % of cases. The main reasons for this can be attributed to work organisation, different definitions of data-set requirements and inadequate knowledge by nurses. Survey results pointed out a need for the renewal of nursing documentation towards a more uniform system based on contemporary health technologies.