Accumulation and penetration behavior of hypericin in glioma tumor spheroids studied by fluorescence microscopy and confocal fluorescence lifetime imaging microscopy.

Glioblastoma WHO IV belongs to a group of brain tumors that are still incurable. A promising treatment approach applies photodynamic therapy (PDT) with hypericin as a photosensitizer. To generate a comprehensive understanding of the photosensitizer-tumor interactions, the first part of our study is focused on investigating the distribution and penetration behavior of hypericin in glioma cell spheroids by fluorescence microscopy. In the second part, fluorescence lifetime imaging microscopy (FLIM) was used to correlate fluorescence lifetime (FLT) changes of hypericin to environmental effects inside the spheroids. In this context, 3D tumor spheroids are an excellent model system since they consider 3D cell-cell interactions and the extracellular matrix is similar to tumors in vivo. Our analytical approach considers hypericin as probe molecule for FLIM and as photosensitizer for PDT at the same time, making it possible to directly draw conclusions of the state and location of the drug in a biological system. The knowledge of both state and location of hypericin makes a fundamental understanding of the impact of hypericin PDT in brain tumors possible. Following different incubation conditions, the hypericin distribution in peripheral and central cryosections of the spheroids were analyzed. Both fluorescence microscopy and FLIM revealed a hypericin gradient towards the spheroid core for short incubation periods or small concentrations. On the other hand, a homogeneous hypericin distribution is observed for long incubation times and high concentrations. Especially, the observed FLT change is crucial for the PDT efficiency, since the triplet yield, and hence the O2 activation, is directly proportional to the FLT. Based on the FLT increase inside spheroids, an incubation time > 30 min is required to achieve most suitable conditions for an effective PDT.

[Resuscitation room diagnostics]. / Schockraumdiagnostik.

CLINICAL PROBLEM: The indication for resuscitation room care is an acute (potentially) life-threatening patient condition. Typical causes for this are polytrauma, acute neurological symptoms, acute chest and abdominal pain or the cause remains unclear at first. The care is always provided in a suitably composed interdisciplinary team. This requires cause-specific standards tailored to the care facility and requires a mutual understanding of the partners involved with regard to specialist interests and care processes. STANDARD RADIOLOGICAL METHODS: Whole-body CT is established for polytrauma imaging and usually each institution has already defined an institutional standard. For the other causes, first imaging with CT is just as common, but the protocols and procedures to be used are often not as clear as in the case of polytrauma. METHODICAL INNOVATION AND EVALUATION: For polytrauma service, ATLS and procedures according to ABCDE already serve as a largely standardized framework in the resuscitation room. For every other group of causes, comparable concepts should be developed and institutionally strive for objectification of continuous improvement. This refers not only to the resuscitation room stay but also to the interfaces before and after resuscitation room service. PRACTICAL RECOMMENDATIONS: After the patient has arrived, it has to be determined whether the assessment of a vital risk is retained. If so, institutionally defined care standards must be followed for the various causes. This concerns the interface logistics, the definition of a team leader including associated tasks, the supply processes including the CT examination protocols as well as the close communication.

Hypericin: Single Molecule Spectroscopy of an Active Natural Drug.

Hypericin is one of the most efficient photosensitizers used in photodynamic tumor therapy (PDT). The reported treatments of this drug reach from antidepressive, antineoplastic, antitumor and antiviral activity. We show that hypericin can be optically detected down to a single molecule at ambient conditions. Hypericin can even be observed inside of a cancer cell, which implies that this drug can be directly used for advanced microscopy techniques (PALM, spt-PALM, or FLIM). Its photostability is large enough to obtain single molecule fluorescence, surface enhanced Raman spectra (SERS), fluorescence lifetime, antibunching, and blinking dynamics. Sudden spectral changes can be associated with a reorientation of the molecule on the particle surface. These properties of hypericin are very sensitive to the local environment. Comparison of DFT calculations with SERS spectra show that both the neutral and deprotonated form of hypericin can be observed on the single molecule and ensemble level.

Review of first clinical experiences with a 1.5 Tesla ceiling-mounted moveable intraoperative MRI system in Europe.

High-field intraoperative MRI (iMRI) systems provide excellent imaging quality and are used for resection control and update of image guidance systems in a number of centers. A ceiling-mounted intraoperative MRI system has several advantages compared to a conventional iMRI system. In this article, we report on first clinical experience with using such a state-of-the-art, the 1.5T iMRI system, in Europe. A total of 50 consecutive patients with intracranial tumors and vascular lesions were operated in the iMRI unit. We analyzed the patients' data, surgery preparation times, intraoperative scans, surgical time, and radicality of tumor removal. Patients' mean age was 46 years (range 8 to 77 years) and the median surgical procedure time was 5 hours (range 1 to 11 hours). The lesions included 6 low-grade gliomas, 8 grade III astrocytomas, 10 glioblastomas, 7 metastases, 7 pituitary adenomas, 2 cavernomas, 2 lymphomas, 1 cortical dysplasia, 3 aneurysms, 1 arterio-venous malformation and 1 extracranial-intracranial bypass, 1 clival chordoma, and 1 Chiari malformation. In the surgical treatment of tumor lesions, intraoperative imaging depicted tumor remnant in 29.7% of the cases, which led to a change in the intraoperative strategy. The mobile 1.5T iMRI system proved to be safe and allowed an optimal workflow in the iMRI unit. Due to the fact that the MRI scanner is moved into the operating room only for imaging, the working environment is comparable to a regular operating room.

ADAM8 expression in breast cancer derived brain metastases: Functional implications on MMP-9 expression and transendothelial migration in breast cancer cells.

Metastatic breast cancer affects long-term survival and is a major cause of cancer death for women worldwide. The Metalloprotease-Disintegrin ADAM8 promotes breast cancer development and brain metastasis in a mouse breast cancer model. Here, abundant ADAM8 expression was detected in primary human breast tumors and associated brain metastases. To investigate the function of ADAM8 in metastasis, MB-231 breast cancer cells with ADAM8 knockdown (MB-231_shA8) and scramble control cells (MB-231_shCtrl) were analyzed for their capability to develop metastases. In vitro, formation of metastatic complexes in hanging drops is dependent on ADAM8 and blocked by ADAM8 inhibition. MB-231_shA8 in contrast to MB-231_shCtrl cells were impaired in transmigration through an endothelial and a reconstituted blood-brain barrier. Out of 23 MMP and 22 ADAM genes, only the MMP-9 gene was affected by ADAM8 knockdown in MB-231_shA8 cells. Following re-expression of wild-type ADAM8 in contrast to ADAM8 lacking the cytoplasmic domain in MB-231_shA8 cells caused increased levels of activated pERK1/2 and pCREB (S133) that were associated with elevated MMP-9 transcription. Application of ADAM8 and MMP-9 antibodies reduced transmigration of MB-231 cells suggesting that ADAM8 affects transmigration of breast cancer cells by MMP-9 regulation. ADAM8-dependent transmigration was confirmed in Hs578t cells overexpressing ADAM8. Moreover, transmigration of MB-231 and Hs578t cells was significantly reduced for cells treated with an antibody directed against P-selectin glycoprotein ligand (PSGL-1), a substrate of ADAM8. From these data we conclude that ADAM8 promotes early metastatic processes such as transendothelial migration by upregulation of MMP-9 and shedding of PSGL-1 from breast cancer cells.

Prolonged Temozolomide Maintenance Therapy in Newly Diagnosed Glioblastoma.

BACKGROUND: The impact of prolonging temozolomide (TMZ) maintenance beyond six cycles in newly diagnosed glioblastoma (GBM) remains a topic of discussion. We investigated the effects of prolonged TMZ maintenance on progression-free survival (PFS) and overall survival (OS). PATIENTS AND METHODS: In this retrospective single-center cohort study, we included patients with GBM who were treated with radiation therapy with concomitant and adjuvant TMZ. For analysis, patients were considered who either completed six TMZ maintenance cycles (group B), continued with TMZ therapy beyond six cycles (group C), or stopped TMZ maintenance therapy within the first six cycles (group A). Patients with progression during the first six TMZ maintenance cycles were excluded. RESULTS: Clinical data from 107 patients were included for Kaplan-Meier analyses and 102 for Cox regressions. Median PFS times were 8.1 months (95% confidence interval [CI] 6.1-12.4) in group A, 13.7 months (95% CI 10.6-17.5) in group B, and 20.9 months (95% CI 15.2-43.5) in group C. At first progression, response rates of TMZ/lomustine rechallenge were 47% in group B and 13% in group C. Median OS times were 12.7 months (95% CI 10.3-16.8) in group A, 25.2 months (95% CI 17.7-55.5) in group B, and 28.6 months (95% CI 24.4-open) in group C. Nevertheless, multivariate Cox regression for patients in group C compared with group B that accounted for imbalances of other risk factors showed no different relative risk (RR) for OS (RR 0.77, p = .46). CONCLUSION: Our data do not support a general extension of TMZ maintenance therapy beyond six cycles. The Oncologist 2017;22:570-575 IMPLICATIONS FOR PRACTICE: Radiation therapy with concomitant and adjuvant temozolomide (TMZ) maintenance therapy is still the standard of care in patients below the age of 65 years in newly diagnosed glioblastoma. However, in clinical practice, many centers continue TMZ maintenance therapy beyond six cycles. The impact of this continuation is controversial and has not yet been addressed in prospective randomized clinical trials. We compared the effect of more than six cycles of TMZ in comparison with exactly six cycles on overall survival (OS) and progression-free survival (PFS) by multivariate analysis and found a benefit in PFS but not OS. Thus, our data do not suggest prolonging TMZ maintenance therapy beyond six cycles, which should be considered in neurooncological practice.

Is Upregulation of Aquaporin 4-M1 Isoform Responsible for the Loss of Typical Orthogonal Arrays of Particles in Astrocytomas?

The astrocytic endfoot membranes of the healthy blood-brain barrier-contacting the capillary-are covered with a large number of the water channel aquaporin 4 (AQP4). They form orthogonal arrays of particles (OAPs), which consist of AQP4 isoform M1 and M23. Under pathologic conditions, AQP4 is distributed over the whole cell and no or only small OAPs are found. From cell culture experiments, it is known that cells transfected only with AQP4-M1 do not form OAPs or only small ones. We hypothesized that in astrocytomas the situation may be comparable to the in vitro experiments expecting an upregulation of AQP4-M1. Quantitative Real-time PCR (qRT-PCR) of different graded astrocytomas revealed an upregulation of both isoforms AQP4 M1 and M23 in all astrocytomas investigated. In freeze fracture replicas of low-grade malignancy astrocytomas, more OAPs than in high-grade malignancy astrocytomas were found. In vitro, cultured glioma cells did not express AQP4, whereas healthy astrocytes revealed a slight upregulation of both isoforms and only a few OAPs in freeze fracture analysis. Taken together, we found a correlation between the decrease of OAPs and increasing grade of malignancy of astrocytomas but this was not consistent with an upregulation of AQP4-M1 in relation to AQP4 M23.

Water Channels Aquaporin 4 and -1 Expression in Subependymoma Depends on the Localization of the Tumors.

BACKGROUND: We analyzed aquaporin 4 and -1 expression in subependymomas, benign and slow growing brain tumors WHO grade I. Ten subependymoma cases were investigated, five of the fossa inferior and five of the fossa superior. METHODS AND RESULTS: Using immunohistochemistry, we observed different aquaporin expression patterns depending on localization: aquaporin 4 and -1 were detected in infratentorial subependymomas in the entire tumor tissue. In contrast, supratentorial subependymomas revealed aquaporin 4 and -1 expression only in border areas of the tumor. PCR analyses however showed no difference in aquaporin 4 expression between all subependymomas independent of localization but at higher levels than in normal brain. In contrast, aquaporin 1 RNA levels were found to be higher only in infratentorial samples compared to supratentorial and normal brain samples. The reason for the different distribution pattern of aquaporin 4 in subependymomas still remains unclear. On the cellular level, aquaporin 4 was redistributed on the surface of the tumor cells, and in freeze fracture replicas no orthogonal arrays of particles were found. This was similar to our previous findings in malignant glioblastomas. From these studies, we know that extracellular matrix molecules within the tumor like agrin and its receptor alpha-dystroglycan are involved in forming orthogonal arrays of particles. In subependymomas neither agrin nor alpha-dystroglycan were detected around blood vessels. CONCLUSIONS: Taken together, we show in this study that in the benign subependymomas aquaporins 1 and 4 are dramatically redistributed and upregulated. We speculate that extracellular environments of infra- and supratentorial subependymomas are different and lead to different distribution patterns of aquaporin 4 and -1.

Experiences in surgery of primary malignant brain tumours in the primary sensori-motor cortex practical recommendations and results of a single institution.

OBJECTIVE: Tumour resection in the Rolandic region is a challenge. Aim of this study is to review a series of patients malignant glioma surgery in the Rolandic region which was performed by combinations of neuronavigation, sonography, 5-aminolevulinic acid fluorescence guided (5-ALA) surgery and intraoperative electrophysiological monitoring (IOM). METHODS: 29 patients suffering malignant gliomas in the motor cortex (17) and sensory cortex (12) were analyzed with respect to functional outcome and grade of resections. RESULTS: Improvement of motor function was seen in 41.5% one week after surgery, 41.5% were stable, only 17% deteriorated. After three months patients had an improvement of motor function in 56%, of Karnofsky Score (KPS) 27% and sensory function was improved in 8%. Deterioration of motor function was seen in 16%, in sensory function 4% and in KPS 28% after three months. 25% showed no residual tumour in early post surgical contrast enhanced MRI. 10% had less than 2% residual tumour and 15% had 2-5% residual tumour. CONCLUSIONS: Preoperative functional neuroimaging, neuronavigation for planning the surgical approach and resection margins, intraoperative sonography and 5-ALA guided surgery in combination with the application of IOM shows that functional outcome and total to subtotal resection of malignant glioma in the Rolandic region is feasible.

Simultaneous subependymomas in monozygotic female twins: further evidence for a common genetic or developmental disorder background.

In this paper, a rare case of subependymoma of the fourth ventricle in identical female twins is reported. Magnetic resonance imaging and CT showed nearly identical locations of the tumors in the fourth ventricle and similar growth patterns of the tumors in both sisters. Likewise, postoperative histopathological analysis of both tumors revealed the typical histological appearance of subependymomas. Subependymoma is a rare, low-grade glioma of the CNS, slowly growing and usually asymptomatic. If symptomatic, a subependymoma can in some cases lead to sudden death caused by pressure on the brainstem or decompensated secondary hydrocephalus. This case demonstrates the importance of detecting tumors early and thereby preventing symptoms arising from increasing intracranial pressure, and optimizing therapy options.

Neurosurgical procedures in the semisitting position: evaluation of the risk of paradoxical venous air embolism in patients with a patent foramen ovale.

OBJECTIVE: To analyze the actual risk for patients with a patent foramen ovale (PFO) to experience a clinically relevant venous air embolism (VAE) during surgery performed in the semisitting position. METHODS: All procedures were performed between January 2008 and December 2009, under general anesthesia and in the semisitting position. Transesophageal echocardiography (TEE) and capnometry were used intraoperatively to monitor for air bubbles in the venous system. RESULTS: Of 200 consecutive patients who all were operated on in the semisitting position, 52 patients (26%) had a diagnosis of PFO. Rates of VAE in patients were graded as follows: grade 0 (no air bubbles visible, no air embolism), 23 patients (44.2%); grade I (air bubbles on TEE), 22 patients (42.3%); grade II (air bubbles on TEE with decrease of end-tidal carbon dioxide [ETCO2] ≤ 3 mm Hg), 2 patients (3.8%); grade III, air bubbles on TEE with decrease of ETCO2 >3 mm Hg, 4 patients (7.7%); grade IV, air bubbles on TEE with decrease of ETCO2 >3 mm Hg and decrease of mean arterial pressure ≥ 20% or increase of heart rate ≥ 40% (or both), 1 patient (1.9%); and grade V, VAE causing arrhythmia with hemodynamic instability requiring cardiopulmonary resuscitation, 0 patients (0%). There were no deaths in this series, and no new or unexplained, mild or severe neurologic deficits were caused by a VAE. CONCLUSIONS: Under standardized anesthesia and neurosurgical protocols, patients with a PFO can be operated on safely in the semisitting position.

Evaluation of a 3-dimensional voxel-based neuronavigation system with perspective image rendering for keyhole approaches to the skull base: an anatomical study.

BACKGROUND: Keeping track of the endoscope tip in 3 planes (axial, coronal, and sagittal) while performing skull base surgeries can be difficult because the surgeon is focused most on the live video images of the endoscope. For that reason, it was the aim of this anatomical cadaver study to evaluate the usefulness of a voxel-based neuronavigation system with 3-dimensional (3D) perspective image rendering for endoscopic procedures through keyhole approaches to the skull base. METHODS: On 5 whole-body fixed cadavers, frontolateral and retrosigmoid approaches were performed bilaterally using a neuronavigation system with 3D perspective image rendering (Cbyon, Med-Surgical Services Inc., Sunnyvale, California). Target points defined on the selected target structures were approached with the navigated ∅ 4-mm 0° endoscope (Storz, Tuttlingen, Germany). Using an Endocameleon 4-mm rigid endoscope capable of changing its angle of view while remaining stationary, the surgical field was checked for injuries before and after insertion of the navigated 0° endoscope. RESULTS: The median neuronavigation registration error was 0.95 mm (range 0.6 to 1.2 mm). Evaluation showed that 100% of the defined targets were reached and visualized. Neither a target structure nor neurovascular structures or surrounding brain tissue were injured by the navigated 0° endoscope. CONCLUSIONS: A neuronavigation system with 3D voxel-based perspective image rendering could potentially improve safety during complex skull base surgeries, and possibly also help to improve surgical results. Such a system, however, cannot replace a neurosurgeon's experience nor surgical skill or anatomical knowledge. It is an excellent teaching tool for young neurosurgeons, but it also has some limitations. Therefore, clinical studies will be necessary to further evaluate the benefits of this type of neuronavigation system in a clinical setting.

Microendoscopy for hypericin fluorescence tumor diagnosis in a subcutaneous glioma mouse model.

BACKGROUND: New treatment strategies for malignant gliomas are indispensible, due to the poor prognosis for patients. Fluorescence diagnosis (FD) and photodynamic therapy (PDT) are currently under intensive investigation and seem to improve the prognosis. Especially for deep seated malignant brain lesions and in order to optimize therapy new diagnostic tools are needed. METHODS: In a syngeneic subcutaneous glioma mouse model we investigated the time dependent hypericin (HYP) uptake in malignant tumor tissue by microendoscopically fluorescence measurements. The HYP fluorescence in tumor was also detected by fluorescence microscopy (FM) and was compared to endoscopic data. RESULTS: Both methods, microendoscopy and FM, demonstrated time dependent HYP uptake in subcutaneously implanted mouse glioma. Maximum of HYP uptake was achieved after 6h, measured with both methods. FM reached a 10-fold increase in fluorescence intensity compared to the autofluorescence. Measured by microendoscopy a 2.2-fold HYP fluorescence intensity compared to the autofluorescence was detected. Microendoscopy enables visualization of small vessels even in healthy brain tissue by intravascular HYP fluorescence. CONCLUSION: The new developed microendoscope enables not only fluorescence based discrimination of tumor and healthy tissue, but also semiquantitative measurements of fluorescence intensities in vivo. Individual repetitive fluorescence diagnosis will become possible by this method and opens up new possibilities for determining optimal settings of light applications for PDT.

Primary cerebral low-grade B-cell lymphoma, monoclonal immunoglobulin deposition disease, cerebral light chain deposition disease and "aggregoma": an update on classification and diagnosis.

BACKGROUND: This work aims to add evidence and provide an update on the classification and diagnosis of monoclonal immunoglobulin deposition disease (MIDD) and primary central nervous system low-grade lymphomas. MIDD is characterized by the deposition of light and heavy chain proteins. Depending on the spatial arrangement of the secreted proteins, light chain-derived amyloidosis (AL) can be distinguished from non-amyloid light chain deposition disease (LCDD). We present a case of an extremely rare tumoral presentation of LCDD (aggregoma) and review the 3 previously published LCDD cases and discuss their presentation with respect to AL. CASE PRESENTATION: A 61-year-old woman presented with a 3½-year history of neurologic symptoms due to a progressive white matter lesion of the left subcortical parieto-insular lobe and basal ganglia. 2 former stereotactic biopsies conducted at different hospitals revealed no evidence of malignancy or inflammation; thus, no therapy had been initiated. After performing physiological and functional magnetic resonance imaging (MRI), the tumor was removed under intraoperative monitoring at our department. Histological analysis revealed large amorphous deposits and small islands of lymphoid cells. CONCLUSION: LCCD is a very rare and obscure manifestation of primary central nervous system low-grade lymphomas that can be easily misdiagnosed by stereotactic biopsy sampling. If stereotactic biopsy does not reveal a definite result, a "wait-and-see" strategy can delay possible therapy for this disease. The impact of surgical removal, radiotherapy and chemotherapy in LCDD obviously remains controversial because of the low number of relevant cases.

Retrospective evaluation of patients with uveal melanoma treated by stereotactic radiosurgery with and without tumor resection.

IMPORTANCE: The present study intended to analyze the suitability of single-dose stereotactic radiotherapy in the treatment of uveal melanoma that cannot be handled with ruthenium-brachytherapy and therefore is a challenge for ophthalmologists concerning local tumor control, as well as preservation of the eye and visual function. OBJECTIVES: To evaluate local tumor control, eye preservation, visual course, radiation complications, metastases, and death after single-dose stereotactic radiotherapy (SDRT) applied exclusively or combined with tumor resection in uveal melanomas that are neither suitable nor favorably located for ruthenium brachytherapy. DESIGN: Retrospective, observational case series. SETTING: Primary care center. PARTICIPANTS: Seventy-eight patients with uveal melanoma were treated. INTERVENTION: Between June 3, 2003, and March 18, 2008, patients with uveal melanoma received SDRT monotherapy (group 1, 60 patients) or SDRT combined with tumor resection (group 2, 18 patients). Radiotherapy was performed with a tumor-surrounding dose of 25 Gy on a linear accelerator. MAIN OUTCOME MEASURES: Local tumor control, eye preservation, visual results, and radiation complications. RESULTS: Within a median follow-up of 33.7 months (range, 0.13-81.13 months), 6 recurrences occurred in group 1; none recurred in group 2. The Kaplan-Meier estimate for local control was 85% at 3 years in group 1 and 100% in group 2 (P = .22). Eye preservation rate was 77% vs 87% at 3 years (groups 1 and 2, respectively) (P = .82). Visual acuity decreased with a median loss of -18 Snellen lines (group 1) and -22 Snellen lines (group 2). More retinopathies (P = .07), opticopathies (P = .27), and rubeotic glaucomas (P = .10) occurred in group 1. No significant difference was observed in the development of metastases (P = .33). The groups differed in overall survival because of 2 deaths occurring shortly after surgery in group 2 for unexplained reasons (P = .06). CONCLUSIONS AND RELEVANCE: Survival analysis suggested that SDRT with combined tumor resection might be associated with increased tumor control and fewer radiation complications than SDRT as monotherapy. Both groups had similar eye retention rates and were comparable concerning the decrease in visual function in most eyes. However, the protocol was stopped after 3 unexplainable deaths after surgery.

Metabolic mapping of gliomas using hybrid MR-PET imaging: feasibility of the method and spatial distribution of metabolic changes.

BACKGROUND AND PURPOSE: The most powerful adjunct to histopathology for the grading of gliomas seems to be the metabolic imaging using positron emission tomography and magnetic resonance spectroscopy (MRS). The purposes of this study were to examine the feasibility of simultaneous acquisition of both techniques for purposes of tumor grading in a newly launched hybrid magnetic resonance positron emission tomography (MR-PET) and to examine the spatial distributions of metabolic changes in gliomas. MATERIALS AND METHODS: Twenty-eight consecutive patients with gliomas underwent simultaneous methionine (Met) MR-PET imaging for detection of the most malignant tumor part before surgical sampling. After coregistration and fusion of MR-PET and MRS data, tumor to normal brain (T/N) Met uptake ratios and the corresponding metabolites peaks (choline [Cho], creatine [Cr], and N-acetylaspartate [NAA]) in MRS were recorded. The patients were divided into 4 types on the basis of the relation between the Met uptake area and the increased metabolite ratios: type I, the increased Met uptake area had at least 50% overlap or was completely within the area of increased Cho/NAA ratio; type II, the increased Met uptake site had less than 50% overlap of increased Cho/NAA ratio site; type III, the increased Met uptake region had no spatial relationship with the "hot" lesions in the MRS maps; and type IV, there was no pathologically increased Met uptake. The surgical sampling was performed in the tumor part with the highest Met uptake and, in the absence of increased Met accumulation, in the site with the highest Cho/NAA ratio. All surgical samples were referred to the neuropathology division for histological grading. RESULTS: A total of 16 low-grade gliomas (World Health Organization grade II) and 12 high-grade gliomas (World Health Organization grade III) were included. Three lesions (10%) of type I were identified. Four lesions (14%) were classified as type II and 6 lesions (21%) were classified as type 3, where the increased Met uptake region had no spatial relationship with the hot lesions in the MRS maps. In 15 of the 28 patients (54%), there was no increased Met accumulation (type 4 lesions). Maps of Cho/NAA and Cr/NAA showed a close spatial relationship in most of the patients. Median T/N Met uptake ratio in the pooled surgically sampled tumor sites was 1.6 (range, 1-3), and median Cho/NAA and Cho/Cr ratios were 2.1 (range, 0.9-5.8) and 1.5 (range, 0.5-8.3), respectively. Spearman rank correlations of the metabolic markers in the low-grade gliomas showed significant correlations between Met uptake and Cr/NAA ratio (ρ = 0.59; P = 0.015) as well as between Cho/NAA and Cr/NAA ratios (ρ = 0.79; P = 0.0002). The normalized tumor creatine was significantly higher in anaplastic tumors compared with the low-grade gliomas (P = 0.001). A tendency for a significant positive correlation was found between normalized tumor creatine and Met uptake in the anaplastic tumors. CONCLUSIONS: Metabolic mapping before histological sampling is feasible using simultaneous MR-PET imaging. High T/N Met uptake ratio reflecting high expression of amino-acid membrane transporters, which is indicative of proliferating tumor cell populations, does not always spatially correlate with neuronal cell loss and cell membrane proliferation (Cho/NAA) seen in MRS. Increased Cr/NAA is associated with increased methionine uptake in low-grade gliomas, whereas normalized creatine in tumor tends to correlate with methionine accumulation, which indicates a possible coupling of these metabolic indices in anaplastic tumors. Thus, spatial distribution differences in gliomas should be taken into account when planning surgical sampling.

Intraoperative visualization of residual tumor: the role of perfusion-weighted imaging in a high-field intraoperative magnetic resonance scanner.

BACKGROUND: High-field, intraoperative magnetic resonance imaging (iMRI) achieves free tumor margins in glioma surgery by involving anatomic neuronavigation and sophisticated functional imaging. OBJECTIVE: To evaluate the role of perfusion-weighted iMRI as an aid to detect residual tumor and to guide its resection. METHODS: Twenty-two patients undergoing intraoperative scanning (in a dual-room 1.5-T magnet setting) during the resection of high-grade gliomas were examined with perfusion-weighted iMRI. The generated relative cerebral blood volume (rCBV) maps were scrutinized for any hot spots indicative of tumor remnants, and region-of-interest analysis was performed. Differences among the rCBV region-of-interest estimates in residual tumor, free tumor margins, and normal white matter were analyzed. Histopathology of the tissue specimens and the neurosurgeon's intraoperative macroscopic estimations were considered the reference standards. RESULTS: In all cases, diagnostic rCBV perfusion maps were generated. Interpretation of perfusion maps demonstrated that gross total resection of gliomas was achieved in 4 of 22 cases (18%), which was macroscopically and histopathologically verified, whereas in 18 of 22 cases (82%), the perfusion-weighted iMRI revealed hot spots indicating subtotal tumor removal. The latter proved to be true in all but 1 case. The receiver-operating characteristic curves of the qualitative visual and quantitative analyses showed excellent sensitivity and specificity rates. Statistical analysis demonstrated statistically significant differences for the mean rCBV and maximum rCBV between residual disease and tumor-free margins (P = .002 for both). CONCLUSION: Perfusion-weighted iMRI may be implemented easily into imaging protocols and may assist the surgeon in detecting residual tumor volume.

Giant intrathoracic left-sided vagal schwannoma.

Extensive intrathoracic tumors are rarely diagnosed radiologically without pre-existing symptoms. If located in the posterior mediastinum, it is most probably a neurogenic tumor. Schwannoma is the most frequent neurogenic neoplasia in this location, and most schwannomas are benign. To specify the diagnosis, a thoracic computed tomography must be done; if the growth is close to the medullary canal, a magnetic resonance tomography of the spinal column is necessary to detect neuroforamen infiltration. Our surgical goal was complete excision of the tumor, although many authors favor a minimally invasive approach. In our patient we performed open, en bloc removal of the tumor; removal of parts of the intraforamen was also necessary, which necessitated revision of the affected neuroforamen. Histologically this was a very rare case of vagal schwannoma (which has an incidence of less than 6% of all neurogenic tumors). This patient has a very promising prognosis following complete tumor resection.

In vitro comparison of hypericin and 5-aminolevulinic acid-derived protoporphyrin IX for photodynamic inactivation of medulloblastoma cells.

BACKGROUND: Hypericin (HYP) is a naturally occurring photosensitizer. Cellular uptake and photodynamic inactivation after incubation with this photosensitizer have neither been examined in medulloblastoma cells in vitro, nor compared with 5-aminolevulinic acid-derived protoporphyrin IX (5-ALA-derived PpIX). METHODS: In 3 medulloblastoma cell lines (D283 Med, Daoy, and D341 Med) the time- and concentration-dependent intracellular accumulation of HYP and 5-ALA-derived PpIX was analyzed by fluorescence microscopy (FM) and FACS. Photocytotoxicity was measured after illumination at 595 nm (HYP) and 635 nm (5-ALA-derived PpIX) in D283 Med cells and compared to U373 MG glioma cells. RESULTS: All medulloblastoma cell lines exhibited concentration- and time-dependent uptake of HYP. Incubation with HYP up to 10 µM resulted in a rapid increase in fluorescence intensity, which peaked between 2 and 4 hours. 5-ALA-derived PpIX accumulation increased in D283 Med cells by 22% over baseline after 5-ALA incubation up to 1.2 mM. Photocytotoxicity of 5-ALA-derived PpIX was higher in D283 Med medulloblastoma compared to U373MG glioma. The LD50 [lethal dose (light dose that is required to reduce cell survival to 50% of control)] of 5-ALA-derived PpIX was 3.8 J/cm(2) in D283 Med cells versus 5.7 J/cm2 in U373MG glioma cells. Photocytotoxicity of HYP in D283 Med cells was determined at 2.5 µM after an incubation time of 2 h and an illumination wavelength of 595 nm. The [Formula: see text] value was 0.47 J/cm(2). CONCLUSION: By its 5-fold increase in fluorescence over autofluorescence levels HYP has excellent properties for tumor visualization in medulloblastomas. The high photocytotoxicity of HYP, compared to 5-ALA-derived PpIX, is convincingly demonstrated by its 8- to 13-fold lower LD50. Therefore HYP might be a promising molecule for intraoperative visualization and photodynamic treatment of medulloblastomas.

An allograft glioma model reveals the dependence of aquaporin-4 expression on the brain microenvironment.

Aquaporin-4 (AQP4), the main water channel of the brain, is highly expressed in animal glioma and human glioblastoma in situ. In contrast, most cultivated glioma cell lines don't express AQP4, and primary cell cultures of human glioblastoma lose it during the first passages. Accordingly, in C6 cells and RG2 cells, two glioma cell lines of the rat, and in SMA mouse glioma cell lines, we found no AQP4 expression. We confirmed an AQP4 loss in primary human glioblastoma cell cultures after a few passages. RG-2 glioma cells if grafted into the brain developed AQP4 expression. This led us consider the possibility of AQP4 expression depends on brain microenvironment. In previous studies, we observed that the typical morphological conformation of AQP4 as orthogonal arrays of particles (OAP) depended on the extracellular matrix component agrin. In this study, we showed for the first time implanted AQP4 negative glioma cells in animal brain or flank to express AQP4 specifically in the intracerebral gliomas but neither in the extracranial nor in the flank gliomas. AQP4 expression in intracerebral gliomas went along with an OAP loss, compared to normal brain tissue. AQP4 staining in vivo normally is polarized in the astrocytic endfoot membranes at the glia limitans superficialis and perivascularis, but in C6 and RG2 tumors the AQP4 staining is redistributed over the whole glioma cell as in human glioblastoma. In contrast, primary rat or mouse astrocytes in culture did not lose their ability to express AQP4, and they were able to form few OAPs.