White-light Microscopy Research Articles

Use of a Single-Fiber Optical Probe for the Detection of Tumor Fluorescence in High-Grade Glioma.

High-grade glioma (HGG) is the most common primary brain tumor in adults. The overall median survival is between 14 and 16 months. Fluorescence-guided surgery by detection of protoporphyrin IX (PpIX) fluorescence has been shown to improve the extent of resection, translating to improved progression-free survival. Microscope-based fluorescence detection techniques are associated with several pain points, some of which may be addressed by using contact-based spectroscopy. We aimed to investigate the accuracy of an optical fiber at detecting PpIX fluorescence by performing real-time spectroscopy in patients with HGG. Adult patients undergoing fluorescence-guided surgery for suspected HGG were recruited prospectively. Intraoperatively, samples from cortex, white matter, and tumor were taken. These samples were interrogated using standard white and blue light microscope techniques and the optical fiber. These specimens were then assessed by neuropathology to determine whether the tumor tissue was present within them. We collected 89 samples from 28 patients. There was an equal ratio of men to women, with a median age of 66.5 years. The accuracy of the probe for detecting PpIX fluorescence was 75.9%, compared with 56.6% for the operating microscope, with a significant improvement in sensitivity (χ2 = 11.84, P < .001). The optical fiber probe was more accurate than the operating microscope for detecting PpIX fluorescence. This technology has potential value in improving the accuracy of fluorescence-guided surgery and has potential practical benefits relating to surgical workflow.

Variability in oil droplet numbers and proportions in the retinas of anole lizards

Colored oil droplets are a common feature in the cones of almost all diurnal lizards. Using white light microscopy, three chromotypes of droplet can be identified in anoles – yellow, green and colorless. These droplets have been associated with different cone classes using microspectrophotometry. The principal member of double cones contain a yellow droplet while the accessory member contains a diffuse yellow pigment. Both members contain the LWS visual pigment. One class of large single cone contains a yellow droplet and the LWS visual pigment. The two remaining classes of large single cone contain the green droplet and either the LWS or MWS visual pigment. As such, by noting the distribution and numbers of the different droplet chromotypes, information about cone distribution, type, and number can be deduced microscopically. Retinas from three anole species (A. cristatellus, A. sagrei, and A. carolinensis) were isolated, flattened and oriented using the two foveae as landmarks. A 19-gauge needle was used to punch out six full-thickness retinal disks from identical retinal regions from both eyes of the three species. The different oil droplets were microscopically identified by color and counted. In all three species at all six retinal areas, the colorless droplets associated with the UVS and SWS single cones represented approximately 10% of the total droplets counted. However, the proportions of the yellow and green droplets were significantly different between the species. For A. cristatellus, 80% of the droplets were green while 10% were yellow. For A. sagrei approximately 85% of the droplets were yellow while only 5% were green. For A. carolinensis 50% of the droplets were yellow while 40% were green. The possible significance of these variable proportions is discussed in terms of possible effects on color vision and ecotype of the three anoles.

Assessment of the effects of 2,4-D-dichlorophenoxyacetic acid-based herbicide exposure in eggs and embryos of golden apple snails using OCT

This study aimed to evaluate the effects of herbicide 2, 4-D-dichlorophenoxy acetic acid on golden apple snail eggs and embryos. Additionally, the study assessed the applicability of optical coherence tomography (OCT), a non-invasive depth cross-sectional microscopic imaging technique, as a novel method, to the best of our knowledge, for studying morphological changes in golden apple snail eggs and embryos, in comparison to the conventional approach of using white light microscopy. The study revealed that the herbicide 2,4-D-dichlorophenoxy acetic acid affected the hatchery rate and morphological changes of the eggs and embryos. The lethal concentration (LC50), representing the concentration of a substance that is expected to cause death in half of the population being studied, of the golden apple eggs and embryos increased with longer exposure time and higher concentrations. The estimated median effective concentration (EC50), which denotes the concentration producing the desired effect in 50% of the exposed golden apple embryos, exhibited a similar trend of change as the LC50. When compared to the microscopic study, it was observed that OCT could be employed to investigate morphological changes of golden apple snail eggs and embryos, enabling evaluation of alterations in both 2D and 3D structures.

Impact of intraoperative cortical indocyanine green extravasation on local vasogenic edema immediately after direct revascularization in an adult with moyamoya disease: illustrative case.

Local vasogenic edema induced after direct revascularization in moyamoya disease (MMD) is associated with blood-brain barrier dysfunction, potentially leading to postoperative cerebral hyperperfusion (CHP) or delayed intracerebral hemorrhage. This phenomenon allows the leakage of fluids, proteins, and other substances from the blood vessels into the extracellular compartment. Typically, such edema is observed postoperatively rather than intraoperatively. A 48-year-old female with ischemic-onset MMD underwent revascularization on her left hemisphere with Suzuki's angiographic stage III. Direct bypass was successfully performed, as confirmed by intravenous indocyanine green (ICG) video angiography. Subsequently, ICG extravasation was observed near the anastomosis site, despite the absence of cortical injury or bleeding under white light microscopy. Postoperative radiological imaging showed reversible pure vasogenic edema in the corresponding area, with no evidence of CHP. The patient did not exhibit neurological deterioration and was discharged home on postoperative day 16. ICG, characterized by low molecular weight, water solubility, and high affinity with plasma proteins, can extravasate, serving as a direct indication of local vasogenic edema induced by direct revascularization in MMD. To enhance comprehension of the vulnerability of the blood-brain barrier in MMD, it is advisable to gather cases with prolonged observations of ICG video angiography after direct revascularization.

The effect of three dental cement types on the corrosion of dental implant surfaces

Statement of problemOne of the main challenges facing dental implant success is peri-implantitis. Recent evidence indicates that titanium (Ti) corrosion products and undetected-residual cement are potential risk factors for peri-implantitis. The literature on the impact of various types of dental cement on Ti corrosion is very limited. PurposeThis study aimed to determine the influence of dental cement on Ti corrosion as a function of cement amount and type. Materials and methodsThirty commercially pure Ti grade 4 discs (19 × 7mm) were polished to mirror-shine (Ra ≈ 40 nm). Samples were divided into 10 groups (n = 3) as a cement type and amount function. The groups were no-cement as control, TempBond NE (TB3mm, TB5mm, and TB8mm), FujiCEM-II (FC3mm, FC5mm, and FC8mm), and Panavia-F-2.0 (PC3mm, PC5mm, and PC8mm). Tafel’s method estimated corrosion rate (icorr) and corresponding potential (Ecorr) from potentiodynamic curves. Electrochemical Impedance Spectroscopy (EIS) data was utilized to obtain Nyquist and Bode plots. An equivalent electrical circuit estimated polarization resistance (Rp) and double-layer capacitance (Cdl). Inductively coupled plasma mass spectrometry (ICP-MS) analysis was conducted to analyze the electrolyte solution after corrosion. pH measurements of the electrolyte were recorded before and after corrosion tests. Finally, the corroded surface was characterized by a 3D white-light microscope and scanning electron microscope. Statistical analysis was conducted using either one-way ANOVA followed by Tukey’s Post Hoc test or Kruskal-Wallis followed by Dunn’s test based on data distribution. ResultsBased on cement amount, FC and PC significantly increased icorr in higher amounts (FC8mm-icorr = 8.22 × 10−8A/cm2, PC8mm-icorr = 5.61 × 10−8A/cm2) compared to control (3.35 × 10−8A/cm2). In contrast, TB3mm decreased icorr significantly compared to the control. As a function of cement type, FC increased icorr the most. EIS data agrees with these observations. Finally, corroded surfaces had higher surface roughness (Ra) compared to non-corroded surfaces. ConclusionThe study indicated that cement types FC and PC led to increased Ti-corrosion as a function of a higher amount. Hence, the implant stability could be impacted by the selection, excessive cement, and a potentially increased risk of peri-implantitis.

Paleoenvironmental changes recorded in the Santa Marta Formation (Santonian–Campanian, Upper Cretaceous), James Ross Island, Antarctica, inferred from palynofacies analyses

The Santa Marta Formation (Santonian–Campanian; James Ross Island, Antarctic Peninsula) is part of one of the most complete sedimentary sequences in the Southern Hemisphere. Paleoenvironmental changes recorded in the formation are reflected in the stratigraphic distribution of sedimentary organic matter in the Lachman Crags and Herbert Sound members. Fifty-three samples from the Lachman Crags section and ten samples from the Herbert Sound section were prepared using standard non-oxidative methods for palynofacies. Analyses were performed using transmitted white light and fluorescence microscopy to identify the groups and subgroups of sedimentary organic matter: non-opaque non-biostructured and biostructured opaque particles, membrane fragments, degraded and non-degraded cuticles, spores, pollen grains, fungal spores, Botryococcus, Palambages, dinoflagellates cysts, amorphous organic matter, pseudoamorphous (product of disintegration of macrophyte tissues) and resins. Three palynofacies associations are distinguished: terrestrial, opaque, and marine palynomorphs. Based on stratigraphically restricted cluster analysis (CONISS), three intervals have been identified: Interval 1, at the base of the Lachman Crags section, conspicuously dominated by the terrestrial palynofacies association. Interval 2, the middle portion of the Lachman Crags section, is marked by alternating terrestrial and opaque palynofacies associations. Interval 3, which coincides with the Herbert Sound section, is distinguished by an abrupt increase in marine elements. The composite section shows progressive transgression, accompanied by a decrease in continental elements, culminating in an open marine environment towards the top of the section.

Biostratigraphy, organic petrography and carbon isotope chemostratigraphy of the Ordovician-Silurian black shales from the Northwestern Domain of Peninsular Malaysia

Integrated biostratigraphy, petrography, organic carbon and carbon isotope chemostratigraphy were used in tandem to assess the paleoenvironment and hydrocarbon potential of the latest Ordovician to Early Silurian basin in the Northwestern Domain of Peninsular Malaysia. Graptolite biostratigraphy indicated a Hirnantian to Aeronian age for the Tanjung Dendang Formation in Pulau Langgun, Langkawi. The graptolite fauna from the Langkawi Islands demonstrates a close association with the South Chinese fauna. The graptolite fragments show a non-granular surface morphology and are mostly present in a long, stipe-like, lath shape when observed under reflected white light microscopy. The pyrites present are relatively small and sparse during the latest Ordovician, suggesting a euxinic condition, but during the Silurian, the pyrites are larger and more common, suggesting anoxic and later dysoxic bottom water. The mean random reflectance of non-granular graptolite in sections perpendicular to the bedding range from 1.8% to 3.07%, and the equivalent vitrinite reflectance ranges from 1.86% Ro to 3.12% Ro, suggesting an overmature stage in term of hydrocarbon generation. The TOC of the Langkawi black shale averages 2.1 wt%, while the rock from the Mahang and Sungai Petani areas measures 1.37 wt% and 0.47% wt%, respectively. δ13Corg chemostratigraphy for the Tanjung Dendang Formation resulted in δ13Corg level between −31.4 ‰ to −28.7 ‰. The Hirnantian Isotope Carbon Excursion (HICE), signalled by a high δ13Corg value, is documented near the base of the formation, followed by a sudden negative shift towards the Ordovician-Silurian boundary. δ13Corg more or less maintained during the Silurian except for slight carbon excursion events during the middle Rhuddanian and early Aeronian. The δ13Corg excursion events from the Tanjung Dendang Formation in Langkawi can be accurately correlated with successions from China, the United Kingdom and Artic Canada.

Spatial Heterogeneity of Biexcitons in Two-Dimensional Ruddlesden-Popper Lead Iodide Perovskites.

Quantum confinement in two-dimensional (2D) Ruddlesden-Popper (RP) perovskites leads to the formation of stable quasi-particles, including excitons and biexcitons, the latter of which may enable lasing in these materials. Due to their hybrid organic-inorganic structures and the solution phase synthesis, microcrystals of 2D RP perovskites can be quite heterogeneous, with variations in excitonic and biexcitonic properties between crystals from the same synthesis and even within individual crystals. Here, we employ one- and two-quantum two-dimensional white-light microscopy to systematically study the spatial variations of excitons and biexcitons in microcrystals of a series of 2D RP perovskites BA2MAn-1PbnI3n+1 (n = 2-4, BA= butylammonium, MA = methylammonium). We find that the average biexciton binding energy of around 60 meV is essentially independent of the perovskite layer thickness (n). We also resolve spatial variations of the exciton and biexciton energies on micron length scales within individual crystals. By comparing the one-quantum and two-quantum spectra at each pixel, we conclude that biexcitons are more sensitive to their environments than excitons. These results shed new light on the ways disorder can modify the energetic landscape of excitons and biexcitons in RP perovskites and how biexcitons can be used as a sensitive probe of the microscopic environment of a semiconductor.

Silicon Vacancy Color Centers in 6H-SiC Fabricated by Femtosecond Laser Direct Writing

As a single photon source, silicon vacancy (VSi) centers in wide bandgap semiconductor silicon carbide (SiC) are expected to be used in quantum technology as spin qubits to participate in quantum sensing and quantum computing. Simultaneously, the new direct femtosecond (fs) laser writing technology has been successfully applied to preparing VSis in SiC. In this study, 6H-SiC, which has been less studied, was used as the processed material. VSi center arrays were formed on the 6H-SiC surface using a 1030-nm-wavelength fs pulsed laser. The surface was characterized by white light microscopy, atomic force microscopy, and confocal photoluminescence (PL)/Raman spectrometry. The effect of fs laser energy, vector polarization, pulse number, and repetition rate on 6H-SiC VSi defect preparation was analyzed by measuring the VSi PL signal at 785-nm laser excitation. The results show that fs laser energy and pulse number greatly influence the preparation of the color center, which plays a key role in optimizing the yield of VSis prepared by fs laser nanomachining.

Penehyclidine hydrochloride protects against lipopolysaccharide-induced acute lung injury by promoting the PI3K/Akt pathway.

Acute lung injury (ALI) attracted attention among physicians because of its high mortality. We aimed to determine whether the phosphatidylinositol-3 kinase (PI3K)/protein kinase B (Akt) pathway is involved in the protective effects of penehyclidine hydrochloride (PHC) against lipopolysaccharide (LPS)-induced ALI. H&E staining was used to observed pathological changes in the lung tissues. ELISA was used to evaluate the concentration of inflammatory mediators in the bronchoalveolar lavage fluid (BALF). White-light microscopy was performed to observe the TUNEL-positive nuclei. The viability of NR8383 alveolar macrophages was determined by using CCK-8. The levels of MPO, MDA, SOD, and GSH-Px were analyzed using ELISA kits. Western blotting was used to evaluate the ERS-associated protein levels and the phosphorylation of PI3K and Akt. PHC administration defended against LPS-induced histopathological deterioration and increased pulmonary edema and lung injury scores, while all of these beneficial effects were inhibited by LY. In addition, PHC administration mitigated oxidative stress as indicated by decreases in lung myeloperoxidase (MPO) and malondialdehyde (MDA) concentrations, and increases in glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) concentrations. It also alleviated LPS-induced inflammation. PHC administration attenuated apoptosis-associated protein levels, improved cell viability, and decreased the number of TdT-mediated dUTP Nick-End Labeling (TUNEL)-positive cells. Furthermore, PHC inhibited ERS-associated protein levels. Meanwhile, the protection of PHC against inflammation, oxidative stress, apoptosis, and ERS was inhibited by LY. Moreover, PHC administration increased PI3K and Akt phosphorylation, indicating that the upregulation of the PI3K/Akt pathway, while this pathway was inhibited by LY. PHC significantly activates the PI3K/Akt pathway to ameliorate the extent of damage to pulmonary tissue, inflammation, oxidative stress, apoptosis, and ERS in LPS-induced ALI.

Rapid multiplex ultrafast nonlinear microscopy for material characterization.

We demonstrate rapid imaging based on four-wave mixing (FWM) by assessing the quality of advanced materials through measurement of their nonlinear response, exciton dephasing, and exciton lifetimes. We use a WSe2 monolayer grown by chemical vapor deposition as a canonical example to demonstrate these capabilities. By comparison, we show that extracting material parameters such as FWM intensity, dephasing times, excited state lifetimes, and distribution of dark/localized states allows for a more accurate assessment of the quality of a sample than current prevalent techniques, including white light microscopy and linear micro-reflectance spectroscopy. We further discuss future improvements of the ultrafast FWM techniques by modeling the robustness of exponential decay fits to different spacing of the sampling points. Employing ultrafast nonlinear imaging in real-time at room temperature bears the potential for rapid in-situ sample characterization of advanced materials and beyond.

Fluorescein-Assisted Microsurgical Resection of Vestibular Schwannoma: A Prospective Feasibility Study.

To evaluate the optimal dose and timing of administration of sodium fluorescein (SF) for selective fluorescence of sporadic vestibular schwannoma (VS) during microsurgery with the YELLOW 560-nm microscope filter (YE560) and to characterize the potential benefit of this fluorescence as determined by intraoperative surgeon assessment. Prospective cohort study. Tertiary referral center. Adult patients undergoing VS microsurgery. Intraoperative intravenous administration of SF and visualization with the YE560. Time to differential fluorescence, duration of fluorescence, correlation of fluorescence of VS with electrostimulation and white light microscopy visual assessment, and likelihood of surgeons to use SF with the YE560 in future cases. Novel use of SF and YE560 during microsurgery achieved selective fluorescence of VS with capabilities to differentiate nerve fascicles and tumor approximately 30 minutes after administration. Nuances of SF administration and timing are discussed. Seventy-five percent of surgeons observed an excellent correlation of selective fluorescence with white light microscopy. Representative images and cases are presented. SF and YE560 may be used in VS microsurgery to visually differentiate VS from surrounding nerves. Potential benefits include enhanced visualization of the tumor-nerve interface for tumor dissection and detection of any residual disease, such as in the fundus after hearing preservation microsurgery.

Microstructure, surface topography and mechanical properties of slip cast and powder injection moulded microspecimens made of zirconia

Abstract Investigations on ceramic microspecimens made of Y2O3- stabilized ZrO2 produced by slip casting or micro powder injection moulding are introduced. During the production of the microspecimens, feedstocks and sintering conditions were varied. Differently moulded specimens were examined with respect to their microstructure and surface topography using light microscopy, scanning electron microscopy (SEM) and confocal white light microscopy. Additionally, the mechanical characteristics were investigated by three-point bending tests using a micro universal testing device. The statistical analysis was realised by means of the Weibull theory and interpreted by the aid of SEM images of fracture surfaces. This research allowed to understand correlations between different feedstocks used, process parameters like the sintering conditions applied and the resulting characteristics as well as material properties of the microspecimens. These results could be used to improve the production process.

Optimization of the continuity of the aspherical production processes in asphericon s.r.o based on subsurface damage and microroughness analysis

In the paper is presented an analysis and optimization of the standardized sub-apertural grinding process used in the serial production in asphericon s.r.o. The monitored parameter was the depth of subsurface damage and surface microroughness. Tested were five grinding processes, which were automatically generated by the internal system, for five different diamond grit sizes (D151, D91, D64, D30, and D15). For evaluation of the depth of the defected layer was used modified wedge polishing method which is suitable for analysis of the rotationally symmetrical sub-apertural grinding processes [1]. For identifying the presence of the subsurface damage two methods were used. Defect detection using an optical microscope, as the broadly used and reliable method, and detection by standard ISO control to get the comparison with the method used in common serial production. The microroughness was measured using a white-light microscope concerning the used grinding tool and the amount of removed material. Within the experiment was found as the most effective two-step process uses D91 for rough grinding and D30 for fine grinding. D91 provides a very good removal characteristic with final subsurface damage of 44 µm which is possible to grind out using the D30 tool in two steps with final subsurface damage 22 µm in a total processing time of 137 minutes. This grinding process is timewise in best balance with 80 minutes long polishing process and therefore minimize the production cost. Result microroughness around 2 nm Sq in the fully polished zone is already limited by the polishing process. Using a finer grinding tool is not bringing improvement in the surface microroughness just shortening polishing time due to lower subsurface damage.

Enhancement of the wettability of graphite-based lithium-ion battery anodes by selective laser surface modification using low energy nanosecond pulses

The electrolyte filling process of battery cells is one of the time-critical bottlenecks in cell production. Wetting is of particular importance here, since only completely wetted electrode sections are working. In order to accelerate and facilitate this process, the authors of this study developed a method to significantly increase the wettability of graphite-based anodes by a laser surface modification using low energy nanosecond laser pulses. The anode surface microstructure was evaluated by means of white-light interferometry and scanning electron microscopy. The assessment of wettability was done by drop test and capillary rise test of the liquid electrolyte. The results show that there is a predominantly selective ablation process for laser energy inputs below 2 J/m by which the graphite active material remains unaffected and the binder material is decomposed. The observed increase in surface roughness correlates with the increasing wettability. Investigations using Raman spectroscopy showed that laser treatment leads to a damage on the crystalline structure of the graphite particle surface. However, treating an entire anode including 6 wt% binder and conductive carbon black has shown that the overall amorphous content of the anodes surface can be reduced by 32% through treating the surface with a laser energy of 1.29 J/m. Up to that point, which is the resulting parameter range for the selective process, it is possible to ablate the amorphous binder and carbon black phase coevally exposing graphite particles while keeping their crystalline structure. Exceeding that range, ablation of the whole anode composite dominates and amorphization of the graphite surface occurs. The electrode’s capacity was tested on half-cells in coin cell format. For the whole laser parameter range investigated, the anodes capacity matches the mass loss caused by laser ablation. No additional capacity loss was observed due to amorphization of the exterior graphite particle’s surface.

Light microscopy of wood using sanded surface instead of slides

Abstract Xylem anatomy is fundamental in studies of the evolution of terrestrial plants, tree ecophysiology, forestry, and wood science. Traditional xylem anatomical studies by light microscopy utilize wood sections. However, the procedures are laborious, and high-quality histological sections have been particularly challenging to achieve from recalcitrant wood species and dry wood material. Modern microscopy offers opportunities for speeding up the xylem anatomical preparations. In this regard, the merits of using a sanded surface for wood anatomical research have been largely overlooked. Sanding of wood surfaces is practiced in dendrochronology and wood identification studies exclusively for the investigation of macro features, such as tree rings, wood porosity, or parenchyma patterns. We conducted microscopic level investigations of sanded surfaces of difficult-to-section high-density woods such as Dalbergia and Quercus species by reflected white light and epifluorescence microscopy. Reflected white light or combinations of reflected light and fluorescence could clearly show xylem micro-features in sanded wood surfaces. The resolution of cell types after sanding with 1000-grit was similar to the resolution obtained by transmitted light microscopy in histological slides. The advantages of sanded wood surfaces compared to traditional wood sections can be summarized as cost- and time-effective sample preparation, large sample area, intact cell walls and tissue structure, preservation of chemical content and extractives, and even focus of the field of view. A simple procedure of wood sanding instead of microscopic slides can be used for xylem microscopy and automatic image analysis of xylem structure.

Interference-based wide-range dynamic tuning of the plasmonic color of single gold nanoparticles.

Dynamic tuning of nanoscale coloration by exploiting localized surface plasmon resonance of gold nanoparticles (AuNPs) combined with an interference coloration mechanism is demonstrated experimentally. When interference between the scattering field from AuNPs and the reflected field from the substrate is observed under back-scattering white-light microscopy, the AuNPs exhibit various colors depending on their distance to the substrate. When the numerical aperture of the microscope objective is optimized, much greater coverage of the color space than was achieved with previously reported plasmon-based approaches is attained. Also, color tunability is examined by exploiting the temperature-induced volume change of a temperature-responsive hydrogel with embedded AuNPs to dynamically modify the distance to the substrate.

5-ALA fluorescence for intraoperative visualization of spinal ependymal tumors and identification of unexpected residual tumor tissue: experience in 31 patients.

Gross-total resection (GTR) is the treatment of choice in the majority of patients suffering from spinal ependymal tumors. In such tumors, the extent of resection (EOR) is considered the key factor for tumor recurrence and thus patient prognosis. However, incomplete resection is not uncommon and leads to increased risk of tumor recurrence. One important cause of incomplete resection is insufficient intraoperative visualization of tumor tissue as well as residual tumor tissue. Therefore, the authors investigated the value of 5-aminolevulinic acid (5-ALA)-induced fluorescence in a series of spinal ependymal tumors for improved tumor visualization. Adult patients who underwent preoperative 5-ALA administration and surgery for a spinal ependymal tumor were included in this study. For each tumor, a conventional white-light microsurgical resection was performed. Additionally, the fluorescence status (strong, vague, or no fluorescence) and fluorescence homogeneity (homogenous or inhomogeneous) of the spinal ependymal tumors were evaluated during surgery using a modified neurosurgical microscope. In intramedullary tumor cases with assumed GTR, the resection cavity was investigated for potential residual fluorescing foci under white-light microscopy. In cases with residual fluorescing foci, these areas were safely resected and the corresponding samples were histopathologically screened for the presence of tumor tissue. In total, 31 spinal ependymal tumors, including 27 intramedullary tumors and 4 intradural extramedullary tumors, were included in this study. Visible fluorescence was observed in the majority of spinal ependymal tumors (n = 25, 81%). Of those, strong fluorescence was noted in 23 of these cases (92%), whereas vague fluorescence was present in 2 cases (8%). In contrast, no fluorescence was observed in the remaining 6 tumors (19%). Most ependymal tumors demonstrated an inhomogeneous fluorescence effect (17 of 25 cases, 68%). After assumed GTR in intramedullary tumors (n = 15), unexpected residual fluorescing foci within the resection cavity could be detected in 5 tumors (33%). These residual fluorescing foci histopathologically corresponded to residual tumor tissue in all cases. This study indicates that 5-ALA fluorescence makes it possible to visualize the majority of spinal ependymal tumors during surgery. Unexpected residual tumor tissue could be detected with the assistance of 5-ALA fluorescence in approximately one-third of analyzed intramedullary tumors. Thus, 5-ALA fluorescence might be useful to increase the EOR, particularly in intramedullary ependymal tumors, in order to reduce the risk of tumor recurrence.

Falcarindiol Purified From Carrots Leads to Elevated Levels of Lipid Droplets and Upregulation of Peroxisome Proliferator-Activated Receptor-γ Gene Expression in Cellular Models.

Falcarindiol (FaDOH) is a cytotoxic and anti-inflammatory polyacetylenic oxylipin found in food plants of the carrot family (Apiaceae). FaDOH has been shown to activate PPARγ and to increase the expression of the cholesterol transporter ABCA1 in cells, both of which play an important role in lipid metabolism. Thus, a common mechanism of action of the anticancer and antidiabetic properties of FaDOH may be due to a possible effect on lipid metabolism. In this study, the effect of sub-toxic concentration (5 μM) of FaDOH inside human mesenchymal stem cells (hMSCs) was studied using white light microscopy and Raman imaging. Our results show that FaDOH increases lipid content in the hMSCs cells as well as the number of lipid droplets (LDs) and that this can be explained by increased expression of PPARγ2 as shown in human colon adenocarcinoma cells. Activation of PPARγ can lead to increased expression of ABCA1. We demonstrate that ABCA1 is upregulated in colorectal neoplastic rat tissue, which indicates a possible role of this transporter in the redistribution of lipids and increased formation of LDs in cancer cells that may lead to endoplasmic reticulum stress and cancer cell death.

Survival after resection of brain metastases with white light microscopy versus fluorescence-guidance: A matched cohort analysis of the Metastasys study data.

Background: Metastatic brain disease continues to have a dismal prognosis. Previous studies achieved a reduction of local recurrence rates by aggressively resecting the peritumoral zone (supramarginal resection) or using 5-aminolaevulinic acid (5-ALA) fluorescence. The aim of the present study is to assess whether the use of 5-ALA has an impact on local recurrence or survival compared to conventional white light microscopic tumor resection.Materials and Methods: We included consecutive patients who underwent surgical resection of brain metastases. Two groups were compared: In the “white light” group, resection was performed with conventional microscopy. In the 5-ALA group, fluorescence guided peritumoral resection was additionally performed after standard microscopic resection. In-brain recurrence and mortality were compared between groups.Results: N = 175 patients were included in the study. All baseline parameters were similarly distributed with no significant difference between surgical groups. Local in-brain recurrence occurred in 21/175 patients (12%) with a rate of 15/119 (12.6%) in the white light and 6/56 (10.7%) in the 5-ALA group (p = 0.720). The use of 5-ALA influenced neither in-brain recurrence (OR 0.59 [CI = 95% 0.18; 1.99], p = 0.40) nor mortality (OR 0.71 [CI = 95% 0.27; 1.85], p = 0.49).Conclusions: The use of 5-ALA did not result in lower in-brain recurrence or mortality compared to the use of white light microscopy. The most prominent predictors of survival remain favorable preoperative performance status, a low tumor diameter and the absence of multiple cerebral lesions.