Injection Of Sodium Fluorescein Research Articles

Role of sodium fluorescein in pediatric low-grade glioma surgery: an update.

Complete surgical resection is still the mainstay in the treatment of central nervous system low-grade tumors, eventually resulting curative. The complete surgical removal of these lesions, however, may be difficult in some cases because of their infiltrative nature. Intraoperative adjuncts may be a game changer. Sodium fluorescein (SF) is among the ideal candidates as intraoperative tools to favor the actual recognition of the tumor extension, since it accumulates in areas of altered blood-brain barrier, a typical characteristic of pediatric gliomas, and has a low rate of adverse events. This work proposes an update of previous works about the evaluation of the feasibility and usefulness of a systematic use of SF in a low-grade lesion group of pediatric patients. Pediatric patients operated on for a resection or a biopsy of a low-grade glial or glioneuronal lesion (WHO grade I and II) at our Institution between September 2021 and December 2023, with the intraoperative use of sodium fluorescein (SF), were enrolled in the study. We collected pre-operative and postoperative clinical and radiological data, intraoperative findings, and post-operative pathological diagnoses. No adverse events were registered related to the intraoperative use of SF. SF appeared useful for the localization of boundaries of tumors, especially when characterized by a high degree of infiltration or by a deep-seated location, and for the checking of possible tumor remnants at the end of surgery. A good tumor-to-healthy tissue contrast was registered when tumor visualization was in a range between 1 to 2h and 30min after SF injection. Possible "false positives" due to intraoperative vascular wall injury and clearance of SF from both tumor and healthy tissue were observed in some cases and still remain open issues. SF is a feasible and safe intraoperative adjunct tool in the surgical removal of pediatric low-grade tumors. SF may show its usefulness especially in selected cases, such as deep-seated lesions and infiltrating tumors. Its safety profile, user-friendly management, and potential utility in both tumor resections and neuronavigated biopsies favor its wider use in the surgical treatment of pediatric low-grade tumors.

Application of Biophysical Properties of Meridians in the Visualization of Pericardium Meridian.

The biophysical properties of the meridian system, an important concept of traditional Chinese medicine, include low impedance, resounding voice, and high acoustic conductance, all of which are helpful for elucidating the essence of meridians. To visualize the human pericardium meridian (PC) based on the resounding voice property of meridians. Visualization of the PC was performed by injection of fluorescein sodium at the PC6 acupoint (Neiguan) on the PC. Before injection, percussion active points (PAPs) were identified by the virtue of their resounding voice properties. After injection, the trajectories of fluorescein migration throughout the body surface were recorded and analyzed. The distribution of fluorescein in the tissue was further studied using cross-sections of hind limbs of mini-pigs, in which fluorescein was injected into low impedance points. The identified PAP lines were colocalized with PC. Following intradermal fluorescein injection, 1-3 fluorescent lines, which were unrelated to the arm veins, were observed in 7 of 10 participants; 85.4% of fluorescent signals were coincident with PAPs and their intensity had a negative correlation with the body mass index (r = -0.56, p = 0.045). Cross-sections showed a Y-shaped fluorescence pattern where the two migration lines on the surface were the two vertices of the "Y." The trajectories of fluorescein in the body are suggestive of the anatomical structure of meridians. The PC is related to the deep horizontal interstitial channels that connect to the body surface through vertical interstitial spaces. These biophysical properties and techniques for meridian visualization are valuable for revealing the anatomical structure of meridians.

Fluorescein Mapping in Vulvar Paget Disease.

Vulvar Paget disease often requires extensive and, in some cases, multiple resections to treat. A fluorescein-mapping procedure followed by a staged vulvectomy may be an effective technique to tailor resection and identify clinically occult lesions. We describe a two-step procedure; first, intravenous fluorescein sodium is injected, and the vulva is illuminated with a Wood's lamp. Representative biopsies are obtained and correlated on final pathology with the extent of disease to develop a final plan for excision. Second, using fluorescein to identify the confirmed areas of disease, the appropriate excisional procedure is performed once mapping biopsy pathology is known. We describe our experience with eight patients with vulvar Paget disease undergoing fluorescein mapping biopsies and staged vulvectomy. Using intravenous fluorescein sodium, all patients were found to have Paget disease beyond the visible margins of their gross lesions. No patients experienced a recurrence of Paget disease within a median follow-up time of 32 months, comparable with other directed methods of surgical resection. We report a technique for the injection of fluorescein sodium for the visualization of vulvar Paget disease capable of providing accurate surgical margins and identification of occult satellite lesions with a high degree of safety and a favorable cost profile. This staged approach to vulvectomy could offer improved accuracy of resection for vulvar Paget disease with few drawbacks.

EXTH-36. ELECTROCONVULSIVE SEIZURE-INDUCED CHANGES IN THE TUMOR MICROENVIRONMENT PROMOTE SURVIVAL IN GLIOMA-BEARING MICE

Abstract PURPOSE Growing evidence indicates that the neurotransmitters dysregulated in psychiatric disorders are similarly dysregulated in glioblastoma (GBM) biology. GBM cells are dependent on bountiful neuronal glutamate, utilize elevated dopamine receptor expression to augment progression, and catabolize serotonin to drive proliferation and inhibit anti-tumor immunity. The clinical induction of seizure, known as electroconvulsive therapy (ECT), has been used by psychiatrists since the 1930s to correct these dysregulations and can additionally improve medication blood-brain barrier (BBB) penetrance. We hypothesized that seizure-induced changes in the glioma microenvironment occur with ECT, slowing tumor progression, increasing BBB permeability, and prolonging overall survival in glioma-bearing mice. METHODS C57BL6 mice were orthotopically injected with CT-2A-Luc mouse glioma cells. Mice were randomized to receive ECT via ear-clip electrodes or sham treatment daily up to five times per week. Intracranial progression was monitored via bioluminescent signal from CT-2A-Luc xenografts. BBB permeability was assessed by subjecting mice to ECT or sham treatment immediately following intravenous injection of sodium fluorescein. RESULTS Intracranial progression was maximally reduced in ECT-treated mice relative to sham-treated mice after 17 ECT treatments (ECT radiance 2.6 x 109 photons/second versus sham 4.7 x 109 photons/second, p=0.013), which was further confirmed by both decreased tumor weight and tumor size on histologic evaluation. This translated into an improvement in overall survival from median 29 days in sham-treated mice to 38 days in ECT-treated mice (p=0.0018). Mean seizure duration was 41.8 seconds and positively correlated with overall survival (Pearson coefficient r=0.63, p=0.028). Brain parenchymal uptake of sodium fluorescein was significantly higher in ECT-treated mice (mean relative increase in ECS to sham radiance of 1.47, p< 0.05). CONCLUSION Repeated ECT slows tumor progression and prolongs overall survival in C57BL6 mice bearing CT-2A-Luc xenografts. The BBB is compromised immediately following ECT. ECT merits further oncologic investigation as a potential therapeutic in GBM.

Characterizing Seizure-Induced Changes in the Glioma Microenvironment

Growing evidence indicates that the neurotransmitters dysregulated in psychiatric disorders are similarly dysregulated in glioblastoma (GBM) biology. Patients with psychiatric disorders are classically thought of having excessive glutamate (major depression, bipolar depression), excessive dopamine (mania, psychosis), and/or insufficient serotonin (major depression, anxiety). Analogously, GBM cells are dependent on bountiful neuronal glutamate, utilize elevated dopamine receptor expression to activate the hypoxic response and augment progression, and catabolize serotonin to drive proliferation. The clinical induction of seizure, known as electroconvulsive therapy (ECT), has been used by psychiatrists since the 1930s to treat severe cases of depression, mania, psychosis, and catatonia. ECT has been shown to decrease extracellular glutamate and glutamate receptor expression in vivo and increase blood-brain barrier (BBB) permeability. ECT, then, may have previously unexplored oncologic value. We hypothesized that seizure-induced changes in the glioma microenvironment occur with ECT, increasing permeability of the BBB, slowing tumor progression, and prolonging overall survival in glioma-bearing mice.C57BL6 mice were orthotopically injected with CT-2A-Luc mouse glioma cells. Mice were randomized to receive ECT via ear-clip electrodes or sham treatment daily up to five times per week until survival endpoints were reached. Seizure duration and rates of tonic hindlimb extension were recorded. Intracranial progression was monitored via bioluminescent signal from CT-2A-Luc xenografts. BBB permeability was assessed by subjecting mice to ECT or sham treatment immediately following tail vein injection of sodium fluorescein. Mice were saline perfused and brains were harvested for fluorescent spectroscopy.Intracranial progression was maximally reduced in ECT-treated mice relative to sham-treated mice after 17 treatments (mean sham radiance 4.7 × 109 photons/s versus mean ECT radiance 2.6 × 109 photon/s, P = 0.013). This translated into an improvement in overall survival from median 29 days in sham-treated mice to 34.5 days in ECT-treated mice (P = 0.0018). Mean seizure duration was 41.8 seconds and positively correlated with overall survival (Pearson coefficient r = 0.63, P = 0.028). Tonic hindlimb extension occurred in 68% of seizures and positively correlated with overall survival (Pearson coefficient r = 0.72, P = 0.0078). Brain parenchymal uptake of sodium fluorescein was significantly higher in ECT-treated mice, with a mean relative increase in ECS to sham radiance of 1.47 (P < 0.05).Repeated ECT slows tumor progression and prolongs overall survival in C57BL6 mice bearing CT-2A-Luc xenografts. The BBB is compromised immediately following ECT. ECT merits further oncologic investigation as a potential therapeutic in GBM.T. Sita: None. L. Hurley: None. C. Dussold: None. S. Sachdev: None. R. Stupp: Research Grant; CarThera, Paris. Consultant/ad hoc advisor for research protocol development; GT Medical Technologies, Insightec; Northwest Biotherapeutics. Scientific Advisory Board; CranioVation, TriAct, Hemispherian. IDMC of an ongoing clinical trial; Celularity. A. Stegh: None.

Quantitative serosal and mucosal optical imaging perfusion assessment in gastric conduits for esophageal surgery: an experimental study in enhanced reality

Introduction/objectiveGastric conduit (GC) is used for reconstruction after esophagectomy. Anastomotic leakage (AL) incidence remains high, given the extensive disruption of the gastric circulation. Currently, there is no reliable method to intraoperatively quantify gastric perfusion. Hyperspectral imaging (HSI) has shown its potential to quantify serosal StO2. Confocal laser endomicroscopy (CLE) allows for automatic mucosal microcirculation quantification as functional capillary density area (FCD-A). The aim of this study was to quantify serosal and mucosal GC’s microperfusion using HSI and CLE. Local capillary lactate (LCL) served as biomarker.MethodsGC was formed in 5 pigs and serosal StO2% was quantified at 3 regions of interest (ROI) using HSI: fundus (ROI-F), greater curvature (ROI-C), and pylorus (ROI-P). After intravenous injection of sodium-fluorescein (0.5 g), CLE-based mucosal microperfusion was assessed at the corresponding ROIs, and LCLs were quantified via a lactate analyzer.ResultsStO2 and FCD-A at ROI-F (41 ± 10.6%, 3.3 ± 3.8, respectively) were significantly lower than ROI-C (68.2 ± 6.7%, p value: 0.005; 18.4 ± 7, p value: 0.01, respectively) and ROI-P (72 ± 10.4%, p value: 0.005; 15.7 ± 3.2 p value: 0.001). LCL value at ROI-F (9.6 ± 4.7 mmol/L) was significantly higher than at ROI-C (2.6 ± 1.2 mmol/L, p value: 0.04) and ROI-P (2.6 ± 1.3 mmol/L, p value: 0.04). No statistically significant difference was found in all metrics between ROI-C and ROI-P. StO2 correlated with FCD-A (Pearson’s r = 0.67). The LCL correlated negatively with both FCD-A (Spearman’s r = − 0.74) and StO2 (Spearman’s r = − 0.54).ConclusionsGC formation causes a drop in serosal and mucosal fundic perfusion. HSI and CLE correlate well and might become useful intraoperative tools.

Preliminary observation of the migration of sodium fluorescein along meridians in the limbs of mini-pigs

<p indent=0mm>Meridians are a core concept in traditional Chinese medicine (TCM) theory. It has been shown in many previous studies that meridians exist in the interstitium, the space through which interstitial fluids flow. Sodium fluorescein (SF) is a small, fluorescent, hydrophilic molecule. SF was injected into the low impedance points (LIPs) or the high impedance points (HIPs) on the limbs of healthy mini-pigs, as determined by a low impedance meridian locator (WQ6F30). Migration tracks were scanned by a digital camera (Canon 5D2) with a narrow band filter and colored flash lamps prior to and after SF injection. The relationships between superficial veins and SF tracks were analyzed using a projection vein finder (V800P). Tissues were frozen on dry ice, and the distribution of SF in the transverse sections of SF tracks was observed. Results reliably showed that seven migrating tracks along the low impedance line along meridians (LILM) were found when SF was injected at LIPs, three of which were on the outside of forelimb, three of which were on the inside of forelimb, and one of which was on the inside of hind limb. The average length of these migration tracks was <sc>5.13 cm.</sc> The migration tracks were 81.4% consistent with LILM, while no overlap was observed with veins. The shape of injected SF in the transverse sections was similar to an inverted triangle, and distributed in the muscle gap. No linear migration was observed when SF was injected at HIP, and the shapes of injected SF were nearly round by local diffusion. The length, width and length-width ratio of SF shapes between injections at LIPs and HIPs were significantly different (<italic>P</italic><0.01). These results imply that the concept of the meridian in TCM may be an unknown interstitial channel.

Solid Lipid Curcumin-loaded Particles for in vivo Fluorescent Imaging in Humans: A Proof of Concept

The possibility to use oral intake of fluorescent dyes approved on humans for intravital fluorescence in vivo imaging is attractive due to its simplicity and non-invasive character. Here we investigate the potential of solid lipid curcumin particles (SLCP) for imaging of capillary permeability using fluorescence video capillaroscopy. Curcumin fluorescence corresponding to 0.7 μg/mL concentration was observed from blood plasma after oral consumption of 2 g of SLCP. However, this signal was ~15% higher than that of blood plasma intrinsic fluorescence, which was itself at least 10-fold lower than the background signal from pericapillary tissue. By comparing the optical properties and concentration to the case of intravenous injection of sodium fluorescein, we analyzed which parameters of the experiment should be optimized for using oral consumption of fluorescing compounds in intravital in vivo capillaroscopy measurements.

Universal fluorescence module for intraoperative fluorescein angiography-a technical report.

Even in specialized centers, suboptimal aneurysm clipping can be as high as 12%. Intraoperative fluorescence angiography with indocyanine green and, more recently, fluorescein sodium have been shown to be a good method for intraoperative flow assessment. However, the cost with the apparatus it entails limits its widespread use. We have developed a low-cost universal fluorescence module (FM) designed to visualize fluorescein and perform intraoperative angiography. The purpose of this paper is to describe this device as well as to present our early experience with its use in the treatment of cerebral aneurysms. A FM was designed and built using a cyan-blue narrow bandpass (460 to 490nm) excitation filter and a yellow-orange longpass (blocking wavelengths under 520nm) barrier filter mounted on a 3D-printed holding tray in a specific disposition to perfectly match the light source and the objective lens of the surgical microscope. It allowed switching from white light to fluorescence mode in a simple and sterile fashion. Its perfect attachment to the microscope was possible by reusing the lens fittings extracted from used original drape sets that would otherwise be discarded. Four patients underwent aneurysm clipping using the FM at two institutions from April to September 2018. A bright green fluorescence against a dark background was observed after intravenous bolus of fluorescein. Blood vessels became obviously distinct from non-contrast-filled structures such as clipped aneurysms and the brain. Vascular anatomy could be appreciated without any distortion, including perforating arteries. Intraoperative fluorescence angiography was successfully performed with the use of this universal FM after intravenous injection of fluorescein sodium. This simple and low-cost device may be useful in resource-limited centers, where other sorts of intraoperative angiography are not available.

Radiopharmaceuticals and Fluorescein Sodium Mediated Triple-Modality Molecular Imaging Allows Precise Image-Guided Tumor Surgery.

Radical resection is the most effective method for malignant tumor treatments. However, conventional imaging cannot fully satisfy the clinical needs of surgical navigation. This study presents a novel triple‐modality positron emission tomography (PET)–Cerenkov radiation energy transfer (CRET)–confocal laser endomicroscopy (CLE) imaging strategy for intraoperative tumor imaging and surgical navigation. Using clinical radiopharmaceuticals and fluorescein sodium (FS), this strategy can accurately detect the tumor and guide the tumor surgery. The FS emission property under Cerenkov radiation excitation is investigated using 2‐deoxy‐2‐18F‐fluoroglucose and 11C‐choline. Performances of the PET–CRET–CLE imaging and the CRET–CLE image‐guided surgery are evaluated on mouse models. The CRET signal at 8 mm depth is stronger than the Cerenkov luminescence at 1 mm depth in phantoms. In vivo experiments indicate that 0.5 mL kg−1 of 10% FS generates the strongest CRET signal, which can be observed immediately after FS injection. A surgical navigation study shows that the tumors are precisely detected and resected using intraoperative CRET–CLE. In summary, a PET–CRET–CLE triple‐modality imaging strategy is developed. This strategy can detect the tumors and precisely guide the tumor resection using clinical pharmaceuticals. This triple‐modality imaging shows high potential in surgical navigation research and clinical translation.

Solid lipid curcumin-loaded particles for in vivo fluorescent imaging in humans: a proof of concept-=SUP=-*-=/SUP=-

The possibility to use oral intake of fluorescent dyes approved on humans for intravital fluorescence in vivo imaging is attractive due to its simplicity and non-invasive character. Here we investigate the potential of solid lipid curcumin particles (SLCP) for imaging of capillary permeability using fluorescence video capillaroscopy. Curcumin fluorescence corresponding to 0.7 μg/ml concentration was observed from blood plasma after oral consumption of 2 g of SLCP. However, this signal was ~ 15% higher than that of blood plasma intrinsic fluorescence, which was itself at least 10-fold lower than the background signal from pericapillary tissue. By comparing the optical properties and concentration to the case of intravenous injection of sodium fluorescein, we analyzed which parameters of the experiment should be optimized for using oral consumption of fluorescing compounds in intravital in vivo capillaroscopy measurements.

Three-Dimensional Transport Model for Intravitreal and Suprachoroidal Drug Injection.

PurposeQuantitative understanding of the transport of therapeutic macromolecules following intraocular injections is critical for the design of efficient strategies in treating eye diseases, such as neovascular (wet) age-related macular degeneration (AMD) and macular edema (ME). Antiangiogenic treatments, such as neutralizing antibodies against VEGF or recently characterized antiangiogenic peptides, have shown promise in slowing disease progression.MethodsWe developed a comprehensive three-dimensional (3D) transport model for intraocular injections using published data on drug distribution in rabbit eyes following intravitreal and suprachoroidal (SC) injection of sodium fluorescein (SF), bevacizumab, and ranibizumab. The model then was applied to evaluate the distribution of small molecules and antiangiogenic proteins following intravitreal and SC injections in human eyes.ResultsThe model predicts that intravitreally administered molecules are substantially mixed within the vitreous following injection, and that the long-term behavior of the injected drug does not depend on the initial mixing. Ocular pharmacokinetics of different drugs is sensitive to different clearance mechanisms. Effective retinal drug delivery is impacted by RPE permeability. For VEGF antibody, intravitreal injection provides sustained delivery to the retina, whereas SC injection provides more efficient, but short-lived, retinal delivery for smaller-sized molecules. Long-term suppression of neovascularization through SC administration of antiangiogenic drugs necessitates frequent injection or sustained delivery, such as microparticle-based delivery of antiangiogenic peptides.ConclusionsA comprehensive 3D model for intravitreal and SC drug injection is developed to provide a framework and platform for testing drug delivery routes and sustained delivery devices for new and existing drugs.

Aging Exacerbates Neuroinflammatory Outcomes Induced by Acute Ozone Exposure.

The role of environmental stressors, particularly exposure to air pollution, in the development of neurodegenerative disease remains underappreciated. We examined the neurological effects of acute ozone (O3) exposure in aged mice, where increased blood-brain barrier (BBB) permeability may confer vulnerability to neuroinflammatory outcomes. C57BL/6 male mice, aged 8-10 weeks or 12-18 months were exposed to either filtered air or 1.0 ppm O3 for 4 h; animals received a single IP injection of sodium fluorescein (FSCN) 20 h postexposure. One-hour post-FSCN injection, animals were transcardially perfused for immunohistochemical analysis of BBB permeability. β-amyloid protein expression was assessed via ELISA. Flow cytometric characterization of infiltrating immune cells, including neutrophils, macrophages, and microglia populations was performed 20 h post-O3 exposure. Flow cytometry analysis of brains revealed increased microglia "activation" and presentation of CD11b, F4/80, and MHCII in aged animals relative to younger ones; these age-induced differences were potentiated by acute O3 exposure. Cortical and limbic regions in aged brains had increased reactive microgliosis and β-amyloid protein expression after O3 insult. The aged cerebellum was particularly vulnerable to acute O3 exposure with increased populations of infiltrating neutrophils, peripheral macrophages/monocytes, and Ly6C+ inflammatory monocytes after insult, which were not significantly increased in the young cerebellum. O3 exposure increased the penetration of FSCN beyond the BBB, the infiltration of peripheral immune cells, and reactive gliosis of microglia. Thus, the aged BBB is vulnerable to insult and becomes highly penetrable in response to O3 exposure, leading to greater neuroinflammatory outcomes.

Fluorescein Angiography in Intracranial Aneurysm Surgery: A Helpful Method to Evaluate the Security of Clipping and Observe Blood Flow.

In cerebral aneurysm surgery, various tools are used to evaluate blood flow, including Doppler ultrasonography, conventional cerebral angiography, and electrophysiological monitoring. Fluorescein and indocyanine green are widely used in vascular and central nervous system tumor neurosurgery; however, their routine utilization in aneurysmal surgery is uncommon, despite the fact that they allow direct visualization of blood flow after aneurysmal sac occlusion, enabling the observation of vessel permeability and the effectiveness of aneurysmal obliteration. We report our initial experience using fluorescein video angiography as a control measure for proper clip placement and control of blood flow in aneurysm surgery, and review the relevant literature. This pilot study presents an initial experience, with enrollment of 10 patients harboring a total of 12 cerebral aneurysms who underwent surgery via clipping and subsequent fluorescence videoangiography control. The intravenous injection was performed to demonstrate the patency of the arteries adjacent to the aneurysm. Following intravenous injection, fluorescein sodium remains in the cerebral vasculature for approximately 3 minutes, providing ample time to evaluate vessel patency and determine whether clip repositioning is needed. None of the patients experienced complications during intravenous injection of fluorescein sodium, and the patency of surrounding vessels was demonstrated in all cases. Fluorescein injection in itself does not present a risk of complications, is simple to use, and offers a clear image of the cerebral vasculature. Thus, this technique is useful for determining vessel patency and the degree of aneurysmal occlusion.

Application of fluorescein sodium in the resection of vermis pilocytic astrocytomas

BackgroundPilocytic astrocytomas (PAs) are slow growing neoplasms and usually located at the cerebellum. There has been certainty regarding the truthful benefit of surgical resection for patients with PA. Gross total resection (GTR) of PAs, especially those being situated in deep regions, remains a surgical challenge. Generally, they are considered as benign and usually develop in young patients. PAs, belonging to WHO I can be cured by radical resection. The patients with PA have excellent prognosis if complete resection can be conducted. The use of fluorescein in vermis PA surgery has not been yet reported. Our data presents fluorescein facilitates surgical resection of vermis PA.MethodsFive milligrams per kilogram of fluorescein sodium was intravenously injected directly before general anesthesia for the three patients with PA. The yellow 560 filter was employed for microsurgical tumor resection. Surgical outcomes were assessed concerning the extent of resection.ResultsMost portion of PA in the three cases was found to be highly fluorescent after intravenous fluorescein sodium injection, which markedly enhanced tumor visibility. Gross total resection in all of the patients was achieved without further neurological deficits. No adverse effects and complications resulting from fluorescein sodium were observed over the postoperative course.ConclusionsIntraoperative guidance by fluorescein sodium as a new, simple, safe, and practical procedure can enhance the fidelity of tumor tissue and increase the possibility of completely resecting PAs.

Potency and Sterility of 10% Sodium Fluorescein Injection, USP Stored in Sterile Polypropylene Syringes for Use During Cystoscopy.

Background: A shortage of indigotindisulfonate sodium has led to a search for an alternative visualizing agent. Objective: The primary objective of this study was to evaluate the potency and sterility of 10% sodium fluorescein, USP solutions stored in sterile polypropylene syringes and refrigerated. Methods: Four samples of 10% fluorescein injection, USP were aseptically drawn up in 3 mL polypropylene syringes and stored in a refrigerator at an average temperature of 3.9°C for 7 days. After 7 days, the samples were cultured for microbial growth. Four other samples were assayed by UV/VIS spectroscopy. Concentration measurements were made at day 0 and at day 7. The pH was also measured at day 0 and day 7. Results: There was no statistical difference between the mean sodium fluorescein concentration at day 0 and at day 7 (α = 0.05, p = .622). There was no statistical difference in the pH of the samples at day 0 and at day 7 (α = 0.05, p = .0689). There was no evidence of microbial growth in any of the samples for the duration of the study period. Conclusions: The findings of this study demonstrate that a sterile solution of 10% sodium fluorescein, USP retained its potency and showed no signs of microbial growth for a period of 7 days when refrigerated and stored in sterile polypropylene syringes.

Fluorescence lifetime measurement with confocal endomicroscopy for direct analysis of tissue biochemistry in vivo.

Confocal endomicroscopy is a powerful tool for in vivo real-time imaging at cellular resolution inside a living body without tissue resection. Microscopic fluorescence lifetime measurement can provide information about localized biochemical conditions such as pH and the concentrations of oxygen and calcium. We hypothesized that combining these techniques could assist accurate cancer discrimination by providing both biochemical and morphological information. We designed a dual-mode experimental setup for confocal endomicroscopic imaging and fluorescence lifetime measurement and applied it to a mouse xenograft model of activated human pancreatic cancer generated by subcutaneous injection of AsPC-1 tumor cells. Using this method with pH-sensitive sodium fluorescein injection, we demonstrated discrimination between normal and cancerous tissues in a living mouse. With further development, this method may be useful for clinical cancer detection.

Hyperthermia of magnetic nanoparticles allows passage of sodium fluorescein and Evans blue dye across the blood–retinal barrier

Purpose: The blood–retina barrier (BRB) is a biological barrier consisting of tightly interconnected endothelial cells inside the retinal vascular network that protects the neural tissue from harmful pathogens and neurotoxic molecules circulating in the bloodstream. Unfortunately, with regard to retinoblastoma, this barrier also prevents systemically administered therapeutics reaching the retinal tissue. In this study we introduce a novel technique to locally and transiently increase BRB permeability for drug delivery using hyperthermia of magnetic nanoparticles (MNPs).Materials and methods: An alternating current (AC) magnetic field was used to induce hyperthermia of locally injected MNPs in the left ophthalmic artery of a rat model. To improve adherence on the surface of the endothelium, commercially available MNPs coated with human transferrin glycoproteins were used. After hyperthermia we assessed the extravasation of systemically injected sodium fluorescein (NaF) as well as Evans blue dye (EBD) into the retinal tissue.Results: Spectrofluorometry and fluorescent microscopy image analysis show a significant increase of dye penetration in the retina where hyperthermia of MNPs was applied.Conclusions: Our proposed new technique can allow both small and large dye molecules to cross the BRB. While the results are preliminary and thorough evaluation of the retinal tissue following hyperthermia is necessary, this technique has the potential to be an effective mean for the treatment of various diseases such as retinoblastoma.

Prospective evaluation of the utility of intraoperative confocal laser endomicroscopy in patients with brain neoplasms using fluorescein sodium: experience with 74 cases.

This study evaluated the utility, specificity, and sensitivity of intraoperative confocal laser endomicroscopy (CLE) to provide diagnostic information during resection of human brain tumors. CLE imaging was used in the resection of intracranial neoplasms in 74 consecutive patients (31 male; mean age 47.5 years; sequential 10-month study period). Intraoperative in vivo and ex vivo CLE was performed after intravenous injection of fluorescein sodium (FNa). Tissue samples from CLE imaging-matched areas were acquired for comparison with routine histological analysis (frozen and permanent sections). CLE images were classified as diagnostic or nondiagnostic. The specificities and sensitivities of CLE and frozen sections for gliomas and meningiomas were calculated using permanent histological sections as the standard. CLE images were obtained for each patient. The mean duration of intraoperative CLE system use was 15.7 minutes (range 3-73 minutes). A total of 20,734 CLE images were correlated with 267 biopsy specimens (mean number of images/biopsy location, in vivo 84, ex vivo 70). CLE images were diagnostic for 45.98% in vivo and 52.97% ex vivo specimens. After initiation of CLE, an average of 14 in vivo images and 7 ex vivo images were acquired before identification of a first diagnostic image. CLE specificity and sensitivity were, respectively, 94% and 91% for gliomas and 93% and 97% for meningiomas. CLE with FNa provided intraoperative histological information during brain tumor removal. Specificities and sensitivities of CLE for gliomas and meningiomas were comparable to those for frozen sections. These data suggest that CLE could allow the interactive identification of tumor areas, substantially improving intraoperative decisions during the resection of brain tumors.

Fast fabrication of microfluidic devices using a low-cost prototyping method

Conventional ways to produce microfluidic devices cost a lot due to the requirements for cleanroom environments and expensive equipment, which prevents the wider applications of microfluidics in academia and in industry. In this paper, a dry film photoresist was utilized in a simple way to reduce the fabrication cost of microfluidic masters. Thus, a fast prototyping and fabrication of microstructures in polydimethylsiloxane microchips through a replica molding technology was achieved in a low-cost setting within 2.5 h. Subsequently, major manufacturing conditions were optimized to acquire well-resolved microfluidic molds, and the replicated microchips were validated to be of good performance. A T-junction channel microchip was fabricated by using a dry film master to generate water droplets of uniform target size. Meanwhile, a gated injection of fluorescein sodium and a contactless conductivity detection of Na+ were both performed in a crosslink channel microchip via capillary electrophoresis, in other words, this fast prototyping and fabrication method would be an efficient, economical way to embody structural design into microfluidic chips for various applications.