Imaging Guidelines during Percutaneous Liver Ablation to Optimize Outcomes and Patient Safety.

Image-guided ablation procedures have become a mainstay in cancer therapy. Typically performed from a percutaneous approach, thermal-based ablation procedures rely heavily on imaging guidance both prior to and during the procedure itself. Advances in imaging as they relate to ablation procedures are as important to successful treatments as advancements in the ablation technology itself. Imaging as it relates to procedural planning, targeting and monitoring, and assessment of procedural endpoint is the focus of this article.

Exploring the Landscape of Aptamers: From Cross-Reactive to Selective to Specific, High-Affinity Receptors for Cocaine.

We reported over 20 years ago MNS-4.1, the first DNA aptamer with a micromolar affinity for cocaine. MNS-4.1 is based on a structural motif that is very common in any random pool of oligonucleotides, and it is actually a nonspecific hydrophobic receptor with wide cross-reactivity with alkaloids and steroids. Despite such weaknesses preventing broad applications, this aptamer became widely used in proof-of-concept demonstrations of new formats of biosensors. We now report a series of progressively improved DNA aptamers recognizing cocaine, with the final optimized receptors having low nanomolar affinity and over a thousand-fold selectivity over the initial cross-reactants. In the process of optimization, we tested different methods to eliminate cross-reactivities and improve affinity, eventually achieving properties that are comparable to those of the reported monoclonal antibody candidates for the therapy of overdose. Multiple aptamers that we now report share structural motifs with the previously reported receptor for serotonin. Further mutagenesis studies revealed a palindromic, highly adaptable, broadly cross-reactive hydrophobic motif that could be rebuilt through mutagenesis, expansion of linker regions, and selections into receptors with exceptional affinities and varying specificities.

Carbon-nanotube field-effect transistors for resolving single-molecule aptamer-ligand binding kinetics.

Small molecules such as neurotransmitters are critical for biochemical functions in living systems. While conventional ultraviolet-visible spectroscopy and mass spectrometry lack portability and are unsuitable for time-resolved measurements in situ, techniques such as amperometry and traditional field-effect detection require a large ensemble of molecules to reach detectable signal levels. Here we demonstrate the potential of carbon-nanotube-based single-molecule field-effect transistors (smFETs), which can detect the charge on a single molecule, as a new platform for recognizing and assaying small molecules. smFETs are formed by the covalent attachment of a probe molecule, in our case a DNA aptamer, to a carbon nanotube. Conformation changes on binding are manifest as discrete changes in the nanotube electrical conductance. By monitoring the kinetics of conformational changes in a binding aptamer, we show that smFETs can detect and quantify serotonin at the single-molecule level, providing unique insights into the dynamics of the aptamer-ligand system. In particular, we show the involvement of G-quadruplex formation and the disruption of the native hairpin structure in the conformational changes of the serotonin-aptamer complex. The smFET is a label-free approach to analysing molecular interactions at the single-molecule level with high temporal resolution, providing additional insights into complex biological processes.

Rapid isolation of anti-idiotype aptamers for quantification of human monoclonal antibodies against SARS-CoV-2 spike protein.

Therapeutic antibodies that block viral entry have already proven to be important, first line drugs for treatments of viral infections. In the case of SARS-CoV-2, combinations of multiple therapeutic antibodies may need to be rapidly identified and formulated in a way that blocks each new, predominant variant of the virus. For efficient introduction of any new antibody combination into patients, it is important to be able to monitor patient-specific pharmacokinetics of individual antibodies, which would include the time course of their specific capacity to block the viral spike proteins. Here, we present three examples of microfluidic-based rapid isolation of companion reagents useful for establishing combination antibody therapies. These reagents are specific three-dimensional imprints of variable regions of individual human monoclonal antibodies against the -spike protein of SARS-CoV-2 virus in the form of oligonucleotide-based ligands (aptamers). We implement these anti-idiotypic aptamers as bioreceptors in graphene-based field-effect transistor sensors to accomplish label free, rapid, and sensitive detection of matching antibodies within minutes. Through this work we have demonstrated the general applicability of anti-idiotype aptamers as capture reagents in quantification of active forms of monoclonal antibodies in complex biological mixtures.

Amplification of Signal on Cell Surfaces in Molecular Cascades.

We can formulate mixtures of oligonucleotide-antibody conjugates to act as molecular cascade-based automata that analyze pairs of cell surface markers (CD markers) on individual cells in a manner consistent with the implementation of Boolean logic-for example, by producing a fluorescent label only if two markers are present. While traditional methods to characterize cells are based on transducing signals from individual cell surface markers, these cascades can be used to combine into a single signal the presence of two or even more CDs. In our original design, oligonucleotide components irreversibly flowed from one antibody to another, driven by increased hybridizations, leading to the magnitude of the final signal on each cell being determined by the surface marker that was the least abundant. This is a significant limitation to the precise labeling of narrow subpopulations, and, in order to overcome it, we changed our design to accomplish signal amplification to a more abundant cell surface marker. We show the AMPLIFY function on two examples: (1) we amplify the fluorescent label from the CD19 marker onto a fivefold more abundant CD45, and (2) we amplify broadly distributed CD45RA to a more constant marker, CD3. We expect this new function to enable the increasingly complex Boolean analysis of cell surfaces.

Lumbar disc herniation in children and elderly patients.

INTRODUCTION: Lumbar disc herniation is a common pathology of young and middle-aged patients. Fissures and tears in the annulus fibrosus become weak points that facilitate herniation of the nucleus pulposus, especially when extreme forces 'attack' the intervertebral disc. A significant biomechanical force applied to a healthy ('normal') disc can have the same effect. Disc protrusions and herniations to varying degrees penetrate the spinal canal.

A functional group-guided approach to aptamers for small molecules.

Aptameric receptors are important biosensor components, yet our ability to identify them depends on the target structures. We analyzed the contributions of individual functional groups on small molecules to binding within 27 target-aptamer pairs, identifying potential hindrances to receptor isolation-for example, negative cooperativity between sterically hindered functional groups. To increase the probability of aptamer isolation for important targets, such as leucine and voriconazole, for which multiple previous selection attempts failed, we designed tailored strategies focused on overcoming individual structural barriers to successful selections. This approach enables us to move beyond standardized protocols into functional group-guided searches, relying on sequences common to receptors for targets and their analogs to serve as anchors in regions of vast oligonucleotide spaces wherein useful reagents are likely to be found.

Wild-Growing and Conventionally or Organically Cultivated Sambucus nigra Germplasm: Fruit Phytochemical Profile, Total Phenolic Content, Antioxidant Activity, and Leaf Elements.

European elder or elderberry (Sambucus nigra L., Viburnaceae) is a plant species with known high pharmaceutical and nutritional value. However, the Greek native germplasm of S. nigra has not been adequately utilized to date as in other regions. This study evaluates the fruit antioxidant potential (total phenolic content and radical scavenging activity) of wild-growing and cultivated germplasm of Greek S. nigra. In addition, nine cultivated Greek S. nigra genotypes were evaluated regarding the effects of fertilization (conventional and organic) on fruit phytochemical and physicochemical potential (total flavonoids, ascorbic acid content, pH, total soluble solids, and total acidity), as well as on the antioxidant potential (total phenolic content and radical scavenging activity) of fruits and leaves. Additionally, an analysis of macro- and micro-elements in the leaves of the cultivated germplasm was performed. The results demonstrated comparatively higher total phenolic contents of fruits of cultivated germplasm. The genotype was the decisive factor in the fruits' phytochemical potential and leaves' total phenolic content of cultivated S. nigra germplasm. Similarly, fertilization regime effects were found to be genotype-dependent, affecting fruit phytochemical and physicochemical attributes. The trace element analysis results were similar, with genotypes varying significantly in their concentrations of macro- and micro-elements. The current work builds on previous domestication attempts for Greek S. nigra, providing new data on the phytochemical potential of this important nutraceutical species.

A Microfluidic Dual-Aptamer Sandwich Assay for Rapid and Cost-Effective Detection of Recombinant Proteins.

While monitoring expression of recombinant proteins is essential for obtaining high-quality biopharmaceutical and biotechnological products, existing assays for recombinant protein detection are laborious, time-consuming and expensive. This paper presents a microfluidic approach to rapid and cost-effective detection of tag-fused recombinant proteins via a dual-aptamer sandwich assay. Our approach addresses limitations in current methods for both dual-aptamer assays and generation of aptamers for such assays by first using microfluidic technology to isolate the aptamers rapidly and then employing these aptamers to implement a microfluidic dual-aptamer assay for tag-fused recombinant protein detection. The use of microfluidic technology enables the fast generation of aptamers and rapid detection of recombinant proteins with minimized consumption of reagents. In addition, compared with antibodies, aptamers as low-cost affinity reagents with an ability of reversible denaturation further decreases the cost of recombinant protein detection. For demonstration, an aptamer pair is isolated rapidly toward His-tagged IgE within two days, and then used in the microfluidic dual-aptamer assay for detecting His-tagged IgE in cell culture media within 10 min and with a limit of detection of 7.1 nM.

Evaluation of NMR predictors for accuracy and ability to reveal trends in 1 H NMR spectra of fatty acids.

Four different nuclear magnetic resonance (NMR) predictors have been evaluated for their ability to predict 600-MHz 1 H spectra of free fatty acids and fatty acid methyl esters of 20 common fatty acids. The predictors were evaluated on two main criteria: (1) their accuracy in direct prediction of the spectra (absolute accuracy) and (2) the ability to reveal trends or predict the change that occurs in the spectra as a result of a change in the fatty acid carbon chain, or by esterification of the free fatty acids to methyl esters (relative accuracy). The absolute accuracy in chemical shift prediction for fatty acids was good, compared with previous reports on a broader range of compounds. All four predictors had median prediction errors for chemical shifts of the signals in fatty acid methyl esters well below 0.1 ppm and as low as 0.015 ppm for one of the predictors. However, all predictors also had outliers with errors far above the upper interquartile range. In general, they also fail to reproduce trends of diagnostic value that were observed in the experimental data or properly predict the result of a minor change in molecular structure. All four predictors depend on experimental data from different origins. This may be a limiting factor for the relative accuracy of the predictors.

Oligonucleotide-Blocked Streptavidin for Biotinylation Analysis.

Binding between streptavidin, or its homologues, to biotin is one of the most widely exploited biological interactions in the biomedical sciences. Controlling the extent of biotinylation is important for meeting the requirements of the intended design and to preserve the native function of the biotin recipient. Within the protein world, a"trial-and-error" optimization approach toward biotinylation reaction conditions is often necessary due to widely varying properties of proteins. Therefore, product analysis is important. We show here that a oligonucleotide-blocked streptavidin, effectively "monovalent streptavidin", can tag biotin moieties individually and the tagged products visualized via a polyacrylamide gel shift assay to reveal the product distribution, i.e., [protein-(biotin)n] products where n = 1, 2, 3, etc. This is in contrast, and complementary, to current commercially available analytical reagents for biotinylation characterization, which use an absorbance or fluorescence signal to yield the mean number of biotin moieties.

Microfluidic isolation of aptamers with affinity towards multiple myeloma monoclonal immunoglobulins.

Multiple myeloma (MM) is a bone marrow cancer of resident plasma cells that affects 125,000 patients in the U.S. with about 30,000 new cases per year. Its signature is the clonal proliferation of a single plasma cell that secretes a patient specific monoclonal immunoglobulin (M-Ig). Targeting the M-Ig in patient serum could allow sensitive and noninvasive identification of minimal residual disease in multiple myeloma. Aptamers, which are single-stranded oligonucleotides with affinity and specificity to a target molecule, have recently been introduced as affinity reagents for recognition of MM M-Igs. Here we exploit microfluidic SELEX technology to enable rapid and efficient generation of aptamers against M-Ig proteins from MM patients. We first characterize the technology by isolating aptamers with affinity towards the monoclonal antibody rituximab as a model M-Ig and then apply the technology to isolating aptamers specifically targeting M-Igs obtained from serum samples of MM patients. We demonstrate that high-affinity DNA aptamers (KD < 50 nM) for M-Ig proteins from a patient sample could be isolated via microfluidic SELEX within approximately 12 h and using less than 100 micrograms of patient M-Ig. Such aptamers can potentially be used in personalized monitoring of minimal residual disease in MM patients.

Chemometric Approach to the Composition of Flavonoid Compounds and Phenolic Acids and Antioxidant Potential of Artemisia Species from Different Habitats.

Four Artemisia species from Serbia were selected for the study: A. annua L., A. absinthium L., A. vulgaris L. and A. scoparia Waldst. et Kit. because of the proven excellent action in treating certain medical conditions and diseases. A. absinthium L., A. vulgaris L., A. annua L. and A. scoparia Waldst. et Kit. collected from different habitats across Serbia (48 samples in total) were studied from the statistical aspect considering the phenolic and flavonoid contents, compositions, and antioxidant activities of methanol extracts in correlation with the soil type. The components were identified using HPLC (High Performance Liquid Chromatography), while antioxidant activities were determined by seven assays (TP (Total phenolic content), TF (Total flavonoid content), DPPH (2,2-diphenyl-1-picrylhydrazyl) radical-based, ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) radical cation-based, FRAP (Ferric Reducing Antioxidant Power), TRP (Total Reducing Power), and CUPRAC (Cupric Reducing Antioxidant Capacity). The results were processed using five statistical methods (PCA (Principal Component Analysis), ANOVA (Analysis of Variance), MANOVA (Multivariate analysis of variance), DA (Discriminant analysis), and AHC (Agglomerative Hierarchical Clustering)). Principal component analysis enabled very well separation of the analyzed Artemisia species based on the content of total phenolics, total flavonoids, and the values obtained from antioxidant tests, but not on the individual compounds identified and quantified by HPLC. The MANOVA analyses showed that for A. scoparia and A. annua there was a significant effect of soil type on the total phenolics, total flavonoids, and antioxidant tests. In contrast, for A. vulgaris and A. absinthium, that effect was not significant. Additional MANOVA analyses showed a significant effect of soil type on phenolic and flavonoid compounds in the case of A. vulgaris, A. annua, and A. absinthium. The overall correct classification rate of all samples of four investigated Artemisia species by the discriminant analysis was 81.25 % using the training sample and 72.92 % the cross-validation results based on TP, TF, and antioxidant tests, but a much lower based on selected compounds identified and quantified by HPLC. MANOVA analyses based on particular Artemisia species show that soil is a significant factor affecting the measurable variables.

Epigenome-wide association of neonatal methylation and trimester-specific prenatal PM2.5 exposure.

Exposure to particulate matter with an aerodynamic diameter smaller than 2.5 microns (PM2.5) can affect birth outcomes through physiological pathways such as inflammation. One potential way PM2.5 affects physiology could be through altering DNA methylation (DNAm). Considering that exposures during specific windows of gestation may have unique effects on DNAm, we hypothesized a timing-specific association between PM2.5 exposure during pregnancy and DNAm in the neonatal epithelial-cell epigenome. Methods: After collecting salivary samples from a cohort of 91 neonates, DNAm was assessed at over 850,000 cytosine-guanine dinucleotide (CpG) methylation sites on the epigenome using the MethylationEPIC array. Daily ambient PM2.5 concentrations were estimated based on the mother's address of primary residence during pregnancy. PM2.5 was averaged over the first two trimesters, separately and combined, and tested for association with DNAm through an epigenome-wide association (EWA) analysis. For each EWA, false discovery rate (FDR)-corrected P < 0.05 constituted a significant finding and every CpG site with uncorrected P < 0.0001 was selected to undergo pathway and network analysis to identify molecular functions enriched by them. Results: Our analysis showed that cg18705808 was associated with the combined average of PM2.5. Pathway and network analysis revealed little similarity between the first two trimesters. Previous studies reported that TMEM184A, the gene regulated by cg18705808, has a putative role in inflammatory pathways. Conclusions: The differences in pathway and network analyses could potentially indicate trimester-specific effects of PM2.5 on DNAm. Further analysis with greater temporal resolution would be valuable to fully characterize the effect of PM2.5 on DNAm and child development.

Evaluation of a clinical decision support tool to predict permanence of retrievable inferior vena cava filters.

OBJECTIVE: To evaluate the usefulness of a published clinical decision support tool to predict the likelihood of a retrievable inferior vena cava (IVC) filter being maintained as a permanent device. METHODS: This multicenter retrospective cohort study included 1498 consecutive patients (852 men and 646 women; median age, 60 years; range, 18-98 years) who underwent retrievable IVC filter insertion between January 2012 and December 2019. The indications for IVC filtration, baseline neurologic disease, history of venous thromboembolism (VTE), and underlying malignancy were recorded. Accuracy, sensitivity, and specificity of a published clinical support tool were calculated to determine the usefulness of the tool. RESULTS: The majority of filters (1271/1498 [85%]) were placed for VTE with a contraindication to anticoagulation. A history of VTE was present in 811 of 1498 patients (54%) patients; underlying malignancy in 531 of 1498 patients (35%), and neurological disease in 258 of 1498 patients (17%). Of the 1498 filters, 456 (30%) were retrieved, 276 (18%) were maintained as permanent devices on follow-up, and 766 (51%) filters were not retrieved. The accuracy of the clinical prediction model was 61%, sensitivity was 60%, and specificity was 62%. CONCLUSIONS: A previously published clinical decision support tool to predict permanence of IVC filters had modest usefulness in the examined population; this factor should be taken into account when using this clinical decision support tool outside of the original study population. Future studies are required to refine the predictive capability of IVC filter decision support tools for broader use across different patient populations.

Spatial navigation performance in people with multiple sclerosis-a large-scale online study.

OBJECTIVE: Spatial navigation has a crucial function in daily life activities, and is therefore strongly linked to quality of life, autonomy, and mobility. Navigation has been shown to be frequently impaired after forms of acquired brain injury, but the impact of MS on navigation ability has yet to be studied. A better understanding of potential navigation problems in this population could improve patient care. Therefore the aim of the current study was to measure objective and subjective navigation performance in people with MS. METHODS: Performance of a large sample of people with MS (N = 359) was compared to a group of matched controls. Additionally, the impact of ambulation and self-reported cognitive performance was studied within the MS sample. Participants filled out the Wayfinding Questionnaire, the patient-reported Expanded Disability Status Scale and the Multiple Sclerosis Neuropsychological Screening Questionnaire for self-report measures. Objective navigation performance was measured with an online navigation test using a virtual environment. RESULTS: Results indicate a lower subjective as well as objective performance in people with MS compared to healthy controls, and a substantial contribution of self-reported cognitive performance on navigation ability. CONCLUSIONS: These findings indicate that spatial navigation can be a significant problem in people with MS, especially in people with MS with other cognitive impairments.

Wearable aptamer-field-effect transistor sensing system for noninvasive cortisol monitoring.

Wearable technologies for personalized monitoring require sensors that track biomarkers often present at low levels. Cortisol­a key stress biomarker­is present in sweat at low nanomolar concentrations. Previous wearable sensing systems are limited to analytes in the micromolar-millimolar ranges. To overcome this and other limitations, we developed a flexible field-effect transistor (FET) biosensor array that exploits a previously unreported cortisol aptamer coupled to nanometer-thin-film In2O3 FETs. Cortisol levels were determined via molecular recognition by aptamers where binding was transduced to electrical signals on FETs. The physiological relevance of cortisol as a stress biomarker was demonstrated by tracking salivary cortisol levels in participants in a Trier Social Stress Test and establishing correlations between cortisol in diurnal saliva and sweat samples. These correlations motivated the development and on-body validation of an aptamer-FET array­based smartwatch equipped with a custom, multichannel, self-referencing, and autonomous source measurement unit enabling seamless, real-time cortisol sweat sensing.

Quality of self-reported cognition: effects of age and gender on spatial navigation self-reports.

Subjective measures of cognitive abilities are often used in various environments, such as clinical, experimental, and professional settings. Here, we assess the quality of such measures, specifically looking into the impact of age and gender. Spatial navigation ability will be used as an exemplary case, given its large individual variation and relevance to the healthy aging process. With a navigation experiment and a self-report questionnaire, the objective and subjective navigation performance of 7150 participants (age 18-89 years) was measured. Results showed the participants provided informative estimates of their cognitive performance. However, strong systematic biases were present related to age and gender. Overestimation increased with increasing age. Overestimation was also found for males, whereas underestimation was found for females. Consideration of such biases is recommended when implementing self-report measures of cognition and considering the potential impact these biases may have on cognitive functioning itself.

Health-Related Quality of Life in Stroke Survivors in Relation to the Type of Inpatient Rehabilitation in Serbia: A Prospective Cohort Study.

Background and objectives: Health-related quality of life after stroke is an important public health issue. The objective of the study was to investigate the relationship between the perceived health-related quality of life in stroke survivors in relation to the type of inpatient rehabilitation. Materials and Methods: Using a random selection method out of a total of 688 patients, every fourth survivor who had a stroke in the period from 1 January 2017 to 31 December 2019 was selected from the admission protocol of the Clinic for Rehabilitation and Physical Medicine of the Clinical Centre Nis, Serbia. A total of 160 first-ever stroke survivors were included (80 underwent additional inpatient rehabilitation and 80 underwent only inpatient rehabilitation in a tertiary health institution) in a twelve-month prospective study. The EuroQuol-5 Dimension (EQ5D) questionnaire and Stroke Impact Scale were used for the assessment. Multivariate linear regression analysis was done. Results: Multivariate linear regression analysis showed that additional inpatient rehabilitation from six up to eight weeks after discharge was significantly associated with better self-reported health condition by 3.9 times (from 1.9 to 8.2), significantly decreased the ranks of EQ5D by 1.78 times (from 1.02 to 3.11), and showed a higher health-related quality of life. We determined a significant increase of strength, emotions, mobility, and participation role in survivors who underwent additional inpatient rehabilitation compared with those who did not. Conclusions: There was a significant difference in health-related quality of life perceived by stroke survivors who underwent additional hospital rehabilitation in relation to those who underwent only inpatient rehabilitation.

Healthcare Professionals' Acceptance of Digital Cognitive Rehabilitation.

With technological possibilities in healthcare steadily increasing, more tools for digital cognitive rehabilitation become available. Acceptance of such technological advances is crucial for successful implementation. Therefore, we examined technology acceptance specifically for this form of rehabilitation in a sample of healthcare providers involved in cognitive rehabilitation. An adjusted version of the Technology Acceptance Model (TAM) questionnaire was used, including the subscales for perceived usefulness, perceived ease of use, subjective norm (toward use), and intention to use, which all contribute to actual use of a specific technology. Results indicate a generally favorable attitude toward the use of digital cognitive rehabilitation and positive responses toward the TAM constructs. Only for subjective norm, a neutral mean response was found, indicating that this could pose a potential obstacle toward implementation. Potential differences between subgroups of different age, gender, and professional background were assessed. Age and gender did not affect the attitude toward digital cognitive rehabilitation. Occupational therapists showed lower scores than healthcare psychologists and physiatrists with regard to perceived usefulness, possibly linked to a difference in operational and managerial tasks. The findings of his study stimulate further implementation of digital cognitive rehabilitation, where the role of subjective norms should be specifically considered.