High incidence of transient perifocal edema following upfront radiosurgery for intraventricular meningiomas.

INTRODUCTION: Intraventricular trigonal meningiomas (ITM) seem to have a tendency for extensive perifocal edema formation following radiosurgery (RS). To further investigate this hypothesis, we undertook the following study. METHODS: We retrospectively reviewed records of patients who underwent RS for intraventricular meningiomas at our institution. RESULTS: From 1999 until 2019, 5 patients underwent single-session RS as primary treatment for ITM. Patients were treated either with a Gamma Knife or a CyberKnife. The mean prescription dose (PD) was 13.0 Gy ± 0.9, the mean tumor volume was 5.8 cc ± 3.1, and the mean follow-up (FU) was 8.9 years ± 5.6. Perifocal edema developed in 4/5 patients after a mean interval of 6.4 months ± 1.2. It was symptomatic in 2/5 patients. The edema regressed spontaneously in 4/5 patients. One of the patients underwent RS for the same ITM twice. One patient's edema was treated medically with steroids, and none of the patients underwent surgery following RS. CONCLUSION: Even though the number of patients is low, there seems to be a comparably high risk for the formation of a perifocal edema following RS for ITM. Single-session RS as primary treatment for ITM seems to be safe and effective even though a perifocal edema is likely to develop. The perifocal edema and the ensuing neurological deficits were transient and could be managed conservatively in all of our 5 cases.

Rhodamine-marked bombesin: a novel means for prostate cancer fluorescence imaging.

The gastrin releasing peptide receptor (GRPR) has been found to be strongly expressed in various types of cancers such as prostate and breast carcinomas. The GRPR ligands gastrin releasing peptide and bombesin can play a very significant role in cancer therapy and diagnostics. In this study we synthesized unlabeled bombesin BBN along with two conjugates in which the correct bombesin (BBN-Rhd) and a mutant bombesin (mBBN-Rhd) sequence was coupled to rhodamine, a fluorescent dye. These novel rhodamine fluorescent conjugates were used to study the targeting and uptake of bombesin on a cellular level. Nine different human cell lines including both tumor and healthy cells were examined using flow cytometry and confocal laser scanning microscopy. GRPR mRNA expression analysis was performed and it was found that the receptor is highly expressed in LNCaP and PC3 cells compared to the rest of other cell lines. Competition experiments were performed to verify the receptor dependence of the labeled conjugates using unmarked bombesin. The present study is a first attempt at direct fluorescence imaging of living cells using bombesin and its target, the GRPR. A rhodamine bombesin conjugate can be used as marker to differentiate between healthy cells and malignant cells such as prostate hyperplasia and prostate carcinoma in the early detection of cancer.

Novel bourgeonal fragrance conjugates for the detection of prostate cancer.

The methods used for detection of prostate cancer and prostate cancer lymph node metastases in medical diagnostics leave room for improvement. Currently, no means of identifying metastasized lymph nodes other than biopsies is available. Markers which are exclusively found on prostate cancer cells present a focal point for potential imaging methods. To complement the established markers like e.g. PCA3-a noncoding mRNA sequence-and PSA-a serine protease-we investigated the ectopically expressed G-protein coupled olfactory receptor OR1D2 as a possible target for prostate-specific detection with its agonist bourgeonal which has been conjugated to two different fluorescent dyes. We performed mRNA expression analysis of the OR1D2 receptor mRNA by reverse transcriptase polymerase chain reaction on LNCaP prostate carcinoma cells and three other non-prostate derived carcinoma cell lines. Additionally, we used flow cytometry to investigate the uptake of fluorescent-dye-bound OR1D2-ligand bourgeonal into the examined carcinoma cell lines. Finally, confocal laser scanning microscopy of in vitro cell culture and in vivo tumor xenografts on mice was performed. We could confirm OR1D2 receptor mRNA overexpression as well as stronger uptake of both bourgeonal conjugates in vitro and in vivo for LNCaP cells compared to the non-prostate derived cell lines. Cytoplasmic accumulation and no adverse effects after in vitro and in vivo application of the conjugates were observed. The conjugates represent a platform for the development of future prostate-specific imaging applications, e.g. detection of metastasized lymph nodes during surgery by intraoperative laser examination.

Using the neurotransmitter serotonin to target imaging agents to glioblastoma cells.

The neurotransmitter serotonin is involved in numerous bodily functions via seven different serotonin receptor subfamilies. Serotonin plays a role in gastrointestinal functions like intestinal secretion or peristalsis and neuropsychiatric events like depression or migraine. One of these subtypes has been found on glioblastoma cells, inducing growth promotion. In our study we attempted to target imaging agents to glioblastoma cells via the serotonin receptor. For this we coupled serotonin to the fluorescent dye rhodamine and the magnetic resonance imaging contrast agent gadolinium (Gd)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA). The cellular uptake, cytotoxicity and detection sensitivity of the conjugates were evaluated by confocal laser scanning microscopy (CLSM), cell growth analysis, flow cytometry and magnetic resonance relaxometry on U373 human glioblastoma cells. Receptor-dependency of the uptake was confirmed by competition experiments with excess of unmarked serotonin. Cellular uptake of the conjugates was found in CLSM, magnetic resonance relaxometry and flow cytometry experiments.CLSM revealed the cytoplasmic character of the uptake. In cell growth analysis experiments no adverse effect of either conjugate on the cells was observed. Competition experiments performed with the conjugates and unmarked serotonin showed decreased conjugate uptake compared to the experiments without competition. In conclusion the neurotransmitter serotonin could be successfully used to target imaging agents into human glioblastoma cells. This makes it of interest for future glioblastoma imaging methods.

Imaging findings in tick-borne encephalitis with differential diagnostic considerations.

OBJECTIVE: The purpose of this article is to provide a practical review of the spectrum of imaging findings in patients with tick-borne encephalitis (TBE) and to address possible differential diagnoses. CONCLUSION: Imaging findings in TBE resemble those of other infections, such as meningoencephalitis. However, a predilection for the thalami, basal ganglia, cerebellum, and anterior horns of the spinal cord suggests the possibility of TBE.

Severe paraneoplastic hypereosinophilia in metastatic renal cell carcinoma.

BACKGROUND: Renal cell carcinoma can cause various paraneoplastic syndromes including metabolic and hematologic disturbances. Paraneoplastic hypereosinophilia has been reported in a variety of hematologic and solid tumors. We present the first case in the literature of severe paraneoplastic hypereosinophilia in a patient with renal cell carcinoma. CASE PRESENTATION: A 46 year-old patient patient with a history of significant weight loss, reduced general state of health and coughing underwent radical nephrectomy for metastasized renal cell carcinoma. Three weeks after surgery, the patient presented with excessive peripheral hypereosinophilia leading to profound neurological symptoms due to cerebral microinfarction. Systemic treatment with prednisolone, hydroxyurea, vincristine, cytarabine, temsirolimus and sunitinib led to reduction of peripheral eosinophils but could not prevent rapid disease progression of the patient. At time of severe leukocytosis, a considerable increase of cytokines associated with hypereosinophilia was measurable. CONCLUSIONS: Paraneoplastic hypereosinophilia in patients with renal cell carcinoma might indicate poor prognosis and rapid disease progression. Myelosuppressive therapy is required in symptomatic patients.

Radiosurgery for Sporadic Benign Synchronous Tumors of the Cerebellopontine Angle.

BACKGROUND: Synchronous cerebellopontine angle (CPA) tumors are a rare entity. Several publications refer to surgery for such tumors and their classification. Yet, there are no publications on upfront radiosurgery for synchronous CPA tumors. CASE DESCRIPTION: The authors present two patients with sporadic synchronous benign CPA tumors who underwent upfront radiosurgery. One patient had two separate schwannomas of the CPA and the other had a schwannoma and a meningioma of the CPA. One patient underwent stepwise radiosurgery treating one tumor after another and the other patient underwent simultaneous radiosurgery for both tumors at the same time. CONCLUSION: Simultaneous and stepwise radiosurgery for synchronous CPA tumors seems to be safe and effective. There were no side effects or complications. To the best of our knowledge this is the first report on upfront radiosurgery for synchronous CPA tumors.

Imaging of human glioma cells by means of a Syndecan-4 directed DOTA-conjugate.

The extracellular glycoprotein Tenascin-C (TN-C) is highly upregulated in gliomas. Therefore, many chemotherapies with radiolabeled antibodies against TN-C have been performed. However, TN-Cs binding partner Syndecan-4 did not play any role as a therapeutic or imaging target in gliomas. We constructed an imaging compound containing the magnetic resonance imaging (MRI) contrast agent gadolinium (Gd)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), the fluorescence dye sulforhodamine and a synthetic Syndecan-4-specific 21 amino acid peptide derived from TN-C. Magnetic resonance relaxometry, confocal laser scanning microscopy, and flow cytometry showed that the Syndecan-4-DOTA-Rhodamine conjugate was taken up into the cytoplasm of human U373 glioma cells without any cytotoxic effects. Competition experiments indicate that this uptake was receptor-mediated. This conjugate might be used for future MRI studies of brain tumors after systemic or intraoperative local application.

The lily-of-the-valley fragrance receptor--potential in prostate cancer imaging.

BACKGROUND: The early diagnosis of prostate cancer and its metastases still remains a great challenge. Recently, olfactory receptors have been found in healthy and malignant prostate tissue. If conjugated to a dye, olfactory receptor ligands would represent candidates for markers of not only olfactory cells but also prostate tissue. Such a conjugate would be of great value for the detection of prostate cancer metastases. METHODS: We coupled sulforhodamine, a fluorescence dye, to undecylic aldehyde, the antagonist of the lily-of-the-valley fragrance receptor. By using confocal laser scanning microscopy and flow cytometry we examined the uptake of this conjugate into various different human cell lines. One healthy prostate cell line, two different prostate carcinoma cell lines, and five other carcinoma cell lines were investigated. CD1 nude mice bearing human PC3 prostate carcinoma xenografts were injected with the conjugate. Rhodamine fluorescence of mouse organ frozen sections was evaluated by confocal laser scanning microscopy. RESULTS: When comparing the seven human cell lines, the conjugate was preferentially taken up by the cytoplasm of healthy and malignant prostate cells. The mice showed high conjugate uptake into the xenografts, but much lower uptake into the mouse organs. After 3 hr of circulation, efflux could be observed in the xenograft sections. Xenograft touch prints confirmed in vivo intracellular accumulation. CONCLUSION: This conjugate may be of potential value in the diagnosis of prostate cancer and its metastases.

Perisylvian white matter connectivity in the human right hemisphere.

BACKGROUND: By using diffusion tensor magnetic resonance imaging (DTI) and subsequent tractography, a perisylvian language network in the human left hemisphere recently has been identified connecting Brocas's and Wernicke's areas directly (arcuate fasciculus) and indirectly by a pathway through the inferior parietal cortex. RESULTS: Applying DTI tractography in the present study, we found a similar three-way pathway in the right hemisphere of 12 healthy individuals: a direct connection between the superior temporal and lateral frontal cortex running in parallel with an indirect connection. The latter composed of a posterior segment connecting the superior temporal with the inferior parietal cortex and an anterior segment running from the inferior parietal to the lateral frontal cortex. CONCLUSION: The present DTI findings suggest that the perisylvian inferior parietal, superior temporal, and lateral frontal corticies are tightly connected not only in the human left but also in the human right hemisphere.

Synthesis of a Novel Curcumin Derivative as a Potential Imaging Probe in Alzheimer's Disease Imaging.

BACKGROUND: Curcumin has been of interest in the field of Alzheimer's disease. Early studies on transgenic mice showed promising results in the reduction of amyloid plaques.However, curcumin is very poorly soluble in aqueous solutions and not easily accessible to coupling as it contains only phenolic groups as potential coupling sites. For these reasons only few imaging studies using curcumin bound as an ester were performed and curcumin is mainly used as nutritional supplement. METHODS: In the present study we produced an aminoethyl ether derivative of curcumin using a nucleophilic substitution reaction. This is a small modification and should not impact the properties of curcumin while introducing an easily accessible reactive amino group. This novel compound could be used to couple curcumin to other molecules using the standard methods of peptide synthesis. We studied the aminoethyl-curcumin compound and a tripeptide carrying this aminoethyl-curcumin and the fluorescent dye fluorescein (FITC-curcumin) in vitro on cell culture using confocal laser scanning microscopy and flow cytometry. Then these two substances were tested ex vivo on brain sections prepared from transgenic mice depicting Alzheimer-like ß-amyloid plaques. RESULTS: In the in vitro CLSM microscopy and flow cytometry experiments we found dot-like unspecific uptake and only slight cytotoxicity correlating with this uptake. As these measurements were optimized for the use of fluorescein as dye we found that the curcumin at 488nm fluorescence excitation was not strong enough to use it as a fluorescence marker in these applications. In the ex vivo sections CLSM experiments both the aminoethyl-curcumin and the FITC-curcumin peptide bound specifically to ß- amyloid plaques. CONCLUSION: In conclusion we successfully produced a novel curcumin derivative which could easily be coupled to other imaging or therapeutic molecules as a sensor for amyloid plaques.

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.

Value of apoptin's 40-amino-acid C-terminal fragment for the differentiation between human tumor and non-tumor cells.

Apoptin, a protein of the chicken anemia virus (CAV), consists of 121 amino acids (aa) and represents a novel, potentially tumor-specific therapeutic and diagnostic agent. The C-terminal part of Apoptin (aa 81-121) is believed to contain a bipartite nuclear localization signal (NLS) (NLS1: aa 82-88 and NLS2: aa 111-121), which is only active in tumor cells after phosphorylation of threonine(108) by tumor-specific cytoplasmic phosphokinases. Furthermore, a nuclear export signal (NES) (aa 97-105) seems to enable nuclear export of Apoptin only in healthy cells. The specificity for tumor cell nuclei also applies to the truncated C-terminal part of Apoptin (aa 81-121), which therefore represents a highly attractive peptide sequence for peptide synthesis. Here we describe for the first time the synthesis of fluorescein isothiocyanate (FITC)- and Dansyl-labelled conjugates containing this C-terminal part of Apoptin, with either phosphorylated or nonphosphorylated threonine(108). The phosphorylated conjugates were synthesized in an attempt to achieve nuclear accumulation in healthy cells, which lack cytoplasmic tumor-specific phosphokinases. Surprisingly, all the conjugates accumulated rapidly within the cell nuclei of both tumor and non-tumor cells from the bladder, brain and prostate and led to cell death. By coupling Apoptin(81-121) to FITC and DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) at either the C- or N-terminus we could exlude that the coupling site is decisive for tumor cell-specific nuclear localization. The labels FITC, DOTA and Dansyl were not responsible for cell death in healthy cells because cell death was not prevented by using an unlabelled Apoptin(81-121) peptide. Cellular and nuclear uptake of the FITC-labelled Apoptin(81-121) peptide was almost completely abolished after altering the NLS2 (replacement of five arginines with serines).

The influence of 2,4,6-tribromophenyl isocyanate on the cellular and nuclear uptake of the SV 40 T antigen nuclear localization sequence.

The objective of the present study was to evaluate the influence of 2,4,6-tribromophenyl isocyanate (TBPI) on the cellular and nuclear uptake of the fluorescein isothiocyanate (FITC) labeled SV 40 T antigen nuclear localization sequence in human LN18 and U373 glioma cells. Therefore, the FITC-labeled nuclear localization sequence (NLS) of the SV 40 T antigen was coupled to 2,4,6-TBPI. This TBPI-NLS conjugate was taken up by the cell nuclei of more than 90% of human malignant glioma cells. The nuclearly stained cells showed clear signs of cell death. However only up to 10% of the cells were stained after incubation with the TBPI-lacking NLS of the SV 40 T antigen together with free, unbound TBPI. These cells stayed alive. TBPI, when bound to small peptides, may be an important component for future drugs against gliomas.

The differential influence of non-iodinated and mono- or diiodinated benzoic acids on cellular and nuclear uptake of the nuclear localization sequence of the SV 40 T antigen.

We synthesized several novel compounds to evaluate the different effects of non-iodinated and mono- or diiodinated benzoic acid on the cellular and nuclear uptake of the SV 40 T antigen nuclear localization sequence (NLS) in human LN18 and U373 glioma cells. The skeletal structure of all the conjugates contained the fluorescein isothiocyanate (FITC)-labeled NLS of the SV 40T antigen, to which either benzoic acid, mono- or diiodobenzoic acid was coupled. As shown by confocal laser scanning microscopy (CLSM) and fluorescence-activated cell sorting (FACS), the basic FITC-labeled NLS alone was taken up by the nuclei of only a few glioma cells which remained intact. The coupling of non-iodinated benzoic acid (BA) did not result in a markedly larger number of nuclearly stained cells. A very marked increase in cells with nuclear staining was found with the conjugate containing monoiodobenzoic acid (MIBA). This was also associated with a high cell death rate. Similar results were obtained with the conjugate containing diiodobenzoic acid (DIBA). However, coincubation with free mono- or diiodobenzoic acid and the basic FITC-labeled NLS did not result in a marked change in the number of strongly stained cells or cell viability compared to the results of incubation with the FITC-labeled NLS alone. Surprisingly, FITC-labeled MIBA- and DIBA-conjugates containing a scrambled SV 40 T antigen NLS were also taken up by the cell nuclei of LN18 and U373 glioma cells and led to cell death. Such mono- or diiodobenzoic acid conjugates may therefore have potential in the development of new non-radioactive drugs against malignant glioma cells.