Protoporphyrin IX Analysis from Blood and Serum in the Context of Neurosurgery of Glioblastoma

Protoporphyrin IX (PPIX) is formed from δ-aminolevulinic acid (ALA) during heme biosynthesis. Due to its cyclic tetrapyrrole core structure, it absorbs in the visible region of the electromagnetic spectrum and is thus colored. Both ALA and PPIX have become of great interest to neurosurgery, because in high-grade glioma, ALA diffuses into the tumor and is converted to PPIX. Fluorescence-guided resection (FGR) takes advantage of both the enrichment of PPIX in the tumor and its fluorescent properties, which enable visualization of tumor tissue. ALA-mediated FGR thus maximizes the extent of resection with better prognosis for patients. Tumor cells are able to produce porphyrins naturally or after administration of ALA, which is also reflected in elevated plasma fluorescence of cancer patients. PPIX might thus serve as a biomarker for monitoring of the tumor burden. A liquid chromatography-mass spectrometry (LC-MS)-based method is presented to quantify PPIX in blood and serum in the context of current fluorescence-based diagnostics. The method is able to distinguish between zinc PPIX, a component of red blood cells of importance in the detection of lead poisoning and iron deficiency anemia, and metal-free PPIX. In a proof-of-principle study, it was used to follow a time course of a glioblastoma patient undergoing surgery and confirmed elevated PPIX blood levels before ALA administration. During surgery, these blood levels increased about four-fold. The here developed 10 min reversed-phase LC-target MS method now allows patient screening with high specificity and throughput

Evaluation of Bacterial Adhesion to the ZrO2 Atomic Layer Deposited on the Surface of Cobalt-Chromium Dental Alloy Produced by DMLS Method

The main purpose of the research was to analyze the influence of surface modification of the cobalt-based alloy used in dental prosthetics by applying zirconium oxide (ZrO2) layers using the ALD (Atomic Layer Deposition) method. The samples were made using the DMLS (Direct Metal Laser Sintering) technique, and their surfaces were prepared in accordance with the principles of removable partial dentures (RPDs). A 50 nm-thick zirconium oxide coating was applied to the prepared substrates. This paper deals with the issues of prosthetic stomatopathy, which is a complex of pathological changes occurring in approx. 40% of the Polish population using removable dentures. Often, these changes, occurring on the mucosa, are related to improper performance, allergic reactions or the multiplication of bacteria on the surface of partial dentures. An innovative method of surface modification was proposed, together with the analysis of its influence on the physicochemical properties of the alloy and the adhesion of bacteria to the surface

Towards Machine Learning-based Quantitative Hyperspectral Image Guidance for Brain Tumor Resection

Complete resection of malignant gliomas is hampered by the difficulty in distinguishing tumor cells at the infiltration zone. Fluorescence guidance with 5-ALA assists in reaching this goal. Using hyperspectral imaging, previous work characterized five fluorophores' emission spectra in most human brain tumors. In this paper, the effectiveness of these five spectra was explored for different tumor and tissue classification tasks in 184 patients (891 hyperspectral measurements) harboring low- (n=30) and high-grade gliomas (n=115), non-glial primary brain tumors (n=19), radiation necrosis (n=2), miscellaneous (n=10) and metastases (n=8). Four machine learning models were trained to classify tumor type, grade, glioma margins and IDH mutation. Using random forests and multi-layer perceptrons, the classifiers achieved average test accuracies of 84-87%, 96%, 86%, and 93% respectively. All five fluorophore abundances varied between tumor margin types and tumor grades (p < 0.01). For tissue type, at least four of the five fluorophore abundances were found to be significantly different (p < 0.01) between all classes. These results demonstrate the fluorophores' differing abundances in different tissue classes, as well as the value of the five fluorophores as potential optical biomarkers, opening new opportunities for intraoperative classification systems in fluorescence-guided neurosurgery.Comment: 22 pages, 8 figure

Protoporphyrin IX in serum of high-grade glioma patients: A novel target for disease monitoring via liquid biopsy

Abstract High-grade gliomas (HGG) carry a dismal prognosis. Diagnosis comprises MRI followed by histopathological evaluation of tissue; no blood biomarker is available. Patients are subjected to serial MRIs and, if unclear, surgery for monitoring of tumor recurrence, which is laborious. MRI provides only limited diagnostic information regarding the differentiation of true tumor progression from therapy-associated side effects. 5-aminolevulinic acid (5-ALA) is routinely used for induction of protoporphyrin IX (PpIX) accumulation in malignant glioma tissue, enabling improved tumor visualization during fluorescence-guided resection (FGR). We investigated whether PpIX can also serve as a serum HGG marker to monitor relapse. Patients (HGG: n = 23 primary, pHGG; n = 5 recurrent, rHGG) undergoing FGR received 5-ALA following standard clinical procedure. The control group of eight healthy volunteers (HCTR) also received 5-ALA. Serum was collected before and repeatedly up to 72 h after drug administration. Significant PpIX accumulation in HGG was observed after 5-ALA administration (ANOVA: p = 0.005, post-hoc: HCTR vs. pHGG p = 0.029, HCTR vs. rHGG p = 0.006). Separation of HCTR from pHGG was possible when maximum serum PpIX levels were reached (CI95% of tMax). ROC analysis of serum PpIX within CI95% of tMax showed successful classification of HCTR and pHGG (AUCROC 0.943, CI95% 0.884–1.000, p < 0.001); the optimal cut-off for diagnosis was 1275 pmol PpIX/ml serum, reaching 87.0% accuracy, 90.5% positive predictive and 84.0% negative predictive value. Baseline PpIX level was similar in patient and control groups. Thus, 5-ALA is required for PpIX induction, which is safe at the standard clinical dosage. PpIX is a new target for liquid biopsy in glioma. More extensive clinical studies are required to characterize its full potential

The Influence of ZnO Oxide Layer on the Physicochemical Behavior of Ti6Al4V Titanium Alloy

Titanium and its alloys are characterized by high biocompatibility and good corrosion resistance as a result of the ability to form a TiO2 oxide layer. However, based on literature data it can be concluded that titanium degradation products, in the form of titanium particles, metal-protein groups, oxides and ions, may cause allergic, inflammatory reactions and bone resorption. The corrosion process of Ti6Al4V in the human body environment may be intensified by a decreased pH and concentration of chloride compounds. The purpose of this article was to analyze the corrosion resistance of the Ti6Al4V alloy, obtained by the selective laser melting method in a corrosion solution of neutral pH and in a solution simulating peri-implant inflammatory conditions. Additionally, the influence of zinc oxide deposited by the atomic layer deposition method on the improvement of the physicochemical behavior of the Ti6Al4V alloy was analyzed. In order to characterize the ZnO layer, tests of chemical and phase composition as well as surface morphology investigation were performed. As part of the assessment of the physicochemical properties of the uncoated samples and those with the ZnO layer, tests of wetting angle, pitting corrosion and impedance corrosion were carried out. The number of ions released after the potentiodynamic test were measured using the inductively coupled plasma atomic emission spectrometry (ICP–AES) method. It can be concluded that samples after surface modification (with the ZnO layer) were characterized by favorable physicochemical properties and had higher corrosion resistance

Protoporphyrin IX Analysis from Blood and Serum in the Context of Neurosurgery of Glioblastoma

Protoporphyrin IX (PPIX) is formed from δ-aminolevulinic acid (ALA) during heme biosynthesis. Due to its cyclic tetrapyrrole core structure, it absorbs in the visible region of the electromagnetic spectrum and is thus colored. Both ALA and PPIX have become of great interest to neurosurgery, because in high-grade glioma, ALA diffuses into the tumor and is converted to PPIX. Fluorescence-guided resection (FGR) takes advantage of both the enrichment of PPIX in the tumor and its fluorescent properties, which enable visualization of tumor tissue. ALA-mediated FGR thus maximizes the extent of resection with better prognosis for patients. Tumor cells are able to produce porphyrins naturally or after administration of ALA, which is also reflected in elevated plasma fluorescence of cancer patients. PPIX might thus serve as a biomarker for monitoring of the tumor burden. A liquid chromatography-mass spectrometry (LC-MS)-based method is presented to quantify PPIX in blood and serum in the context of current fluorescence-based diagnostics. The method is able to distinguish between zinc PPIX, a component of red blood cells of importance in the detection of lead poisoning and iron deficiency anemia, and metal-free PPIX. In a proof-of-principle study, it was used to follow a time course of a glioblastoma patient undergoing surgery and confirmed elevated PPIX blood levels before ALA administration. During surgery, these blood levels increased about four-fold. The here developed 10 min reversed-phase LC-target MS method now allows patient screening with high specificity and throughput

Energy landscape for Li-ion diffusion in the garnet-type solid electrolyte Li6.5_{6.5}La3_3Zr1.5_{1.5}Nb0.5_{0.5}O12_{12} (LLZO-Nb)

A comprehensive understanding of the nexus of diffusion mechanisms on the atomic scale as well as structural influences on the ionic motion in solid electrolytes is key for further development of high-performing all-solid-state batteries. Therefore, current research not only focuses on the search for innovative materials, but also on the study of diffusion pathways and ion dynamics in ionic conductors. In this context, we report on the extended characterization of the ionic electrolyte Li$_{6.5}$La$_3$Zr$_{1.5}$Nb$_{0.5}$O$_{12}$ (LLZO-Nb). The commercially available material is analyzed by a combination of powder X-ray (either lab- or synchrotron-based) and neutron diffraction. Details of lithium disorder were obtained from high-resolution neutron diffraction data, from which the ionic transport of Li ions was determined by applying the maximum entropy method in combination with the one-particle potential formalism

Determination of δ-aminolevulinic acid-induced protoporphyrin IX in blood

In neurosurgery, δ-aminolevulinic acid-induced fluorescence-guided resection (ALA-FGR) of high grade gliomas (HGGs) improves tumor resection. ALA is a precursor of protoporphyrin IX (PPIX) and accumulates in tumor tissue assisting surgery by its fluorescence. In an effort to investigate whether ALA-induced PPIX can also be a serum biomarker for HGGs, a method for its detection in blood was developed. It involved analyte purification by liquid-liquid-extraction and its detection using target-MRM with an ion trap mass spectrometer coupled to capillary liquid chromatography. Analysis was possible from both serum and anticoagulated whole blood, but only ¼ of the starting sample volume was needed in case of the latter (4 ml serum vs. 1 ml whole blood). However, handling was also more challenging for whole blood so that, ultimately, an optimized method for the analysis of serum is aimed for. It will also resolve the problem that PPIX is measured as the sum of PPIX and endogenous Zn-bound PPIX in whole blood, while the detection of the latter can be avoided in serum. Preliminary results indicate higher PPIX levels in whole blood of patients suffering from HGG, who received ALA prior to venipuncture, in comparison to healthy controls. A time-series of PPIX levels in whole blood of a HGG patient undergoing surgery agreed with the observed fluorescence changes in tissue. These promising results encourage further method optimization and investigations both in whole blood and serum, which provides the purer analyte, but much less of it.In der Neurochirurgie verbessert die δ-Aminolevulinsäure-induzierte Fluoreszenz-geleitete Resektion (ALA-FGR) von high grade Gliomas (HGGs) die Tumor Entfernung. ALA ist ein Vorläufer von Protoporphyrin IX (PPIX) und akkumuliert in Tumorgewebe. Durch die PPIX-Fluoreszenz wird der Tumor während der Operation besser sichtbar. Um zu untersuchen, ob ALA-induziertes PPIX auch ein Serum-Biomarker für HGGs sein kann, wurde eine Methode für seine Messung in Blut entwickelt. Diese basierte auf einer Reinigung des Analyten mittels Flüssig-Flüssig-Extraktion und seinem Nachweis durch Target-MRM mit einer Ionenfalle gekoppelt an Kapillar-Flüssigchromatographie. Die Analyse war sowohl aus Serum als auch aus antikoaguliertem Vollblut möglich, aber bei letzterem wurde nur ¼ des Anfangsvolumens benötigt (4 ml Serum vs. 1 ml Vollblut). Jedoch war die Probenverarbeitung im Fall von Vollblut auch eine größere Herausforderung, so dass ultimativ eine optimierte Methode für die Serumanalyse geschaffen werden soll. Damit wird zusätzlich das Problem gelöst, dass PPIX im Vollblut als Summenparameter von PPIX und endogenem Zn-gebundenem PPIX gemessen wird, während die Bestimmung von letzterem in Serum vermieden werden kann. Vorläufige Ergebnisse indizieren höhere PPIX-Level in Vollblut bei HGG-Patienten nach ALA-Gabe im Vergleich zu gesunden Kontrollen. Eine Zeitserie der Vollblut-PPIX-Level einer HGG-Patientin während der OP stimmte mit den Änderungen der Gewebsfluoreszenz überein. Diese positiven Ergebnisse sprechen für weitere Optimierungsversuche sowohl in Vollblut als auch in Serum

Impact of Surface Treatment on the Functional Properties Stainless Steel for Biomedical Applications

The main goal of the carried out tests was to analyze the influence of the surface modification of a substrate by depositing composite ZnO layers by the Atomic Layer Deposition (ALD) method. The samples were subjected to preliminary surface modification consisting of being sandblasted and electropolished. A ZnO layer was applied to the prepared substrates by the ALD method. As a precursor of ZnO, diethylzinc (DEZ) was used, which reacted with water, enabling the deposition of the thin films. The chamber temperature was as follows: T = 100&ndash;300 &deg;C. The number of cycles was 500 and 1500. As part of the assessment of the physicochemical properties of the resulting surface layers, the tests of chemical composition of the layer, pitting corrosion, impedance corrosion, adhesion to the metal substrate, morphology surface, and wettability were carried out. On the basis of the obtained research, it was found that a composite ZnO layer deposited onto a substrate previously subjected to the electrochemical polishing process has more favorable physicochemical properties. Moreover, an influence of temperature and the number of cycles of the deposition process on the obtained properties was observed, where the ZnO layer was characterized by more favorable properties at a temperature of 200&ndash;300 &deg;C at 1500 cycles of the deposition process

Harnessing the microbiome to prevent global biodiversity loss

Global biodiversity loss and mass extinction of species are two of the most critical environmental issues the world is currently facing, resulting in the disruption of various ecosystems central to environmental functions and human health. Microbiome-targeted interventions, such as probiotics and microbiome transplants, are emerging as potential options to reverse deterioration of biodiversity and increase the resilience of wildlife and ecosystems. However, the implementation of these interventions is urgently needed. We summarize the current concepts, bottlenecks and ethical aspects encompassing the careful and responsible management of ecosystem resources using the microbiome (termed microbiome stewardship) to rehabilitate organisms and ecosystem functions. We propose a real-world application framework to guide environmental and wildlife probiotic applications. This framework details steps that must be taken in the upscaling process while weighing risks against the high toll of inaction. In doing so, we draw parallels with other aspects of contemporary science moving swiftly in the face of urgent global challenges