NIMG-64. INTRAOPERATIVE LANGUAGE MAPPING USING GAMMA-BAND MODULATIONS OF ELECTROCORTICOGRAM (ECOG) INDUCED BY WORD/SOUND CATEGORIZATION TASK: VALIDATION WITH REPRODUCIBLE SPEECH ARRESTS DURING LINGUISTIC TASKS

OBJECTIVE

Determination of the correlation between gamma-band modulations of electrocorticogram (ECoG) induced by linguistic tasks and reproducible speech arrests caused by bipolar direct cortical stimulations (DCS).

METHODS

3 subjects (age 39, 56, 64 years) with left temporal lobe glioma underwent surgery involving awake craniotomy. A 4x8 ECoG electrode grid (2.3mm contact exposure, 1cm contact spacing) was placed above the respective tumor area. A MATLAB-Simulink based real-time software system running on a portable laptop computer was used to map gamma-band modulations as a 2D heat map while the subjects engaged in different linguistic tasks: word/sound categorization by pressing a button, object naming, action naming, written descriptive naming, and auditory descriptive naming. Auditory stimulus was applied during word/sound categorization task (duration 300 – 500ms), auditory descriptive naming ( > 1s); other tasks involved visual stimulus only. The subjects repeated the four naming tasks while bipolar DCS (2/4/6 mA, 60Hz, 2s) was applied at different electrode pairs.

RESULTS

The electrodes having stronger gamma-band modulations were distinct for different tasks. Reproducible speech arrests occurred during object, action, auditory naming tasks while stimulating specific electrode pairs, even though not all these electrodes had strong activations during these tasks. Across all subjects these electrodes had strong activations consistently during word/sound categorization tasks, starting as early as 250ms and lasting even after the auditory stimuli were terminated (~ 650ms). The longer activations can be associated with word recognition process. The subjects self-reported about having difficulty in comprehension rather than speech production during speech arrests. 3D brain rendering using MRI images showed that the speech arrest electrodes were identically located on the superior temporal gyrus, inferior to central sulcus for all 3 subjects.

CONCLUSION

Intraoperative language mapping guided by gamma-band ECoG modulations induced by word/sound categorization tasks can be utilized to localize eloquent cortex associated with auditory processing.

NCOG-14. INTRAOPERATIVE COGNITIVE-LINGUISTIC MAPPING GUIDED BY VISUALIZATION OF GAMMA BAND MODULATION ELECTROCORTICOGRAMS: PROOF OF CONCEPT IN A PATIENT WITH LEFT TEMPORAL AND OCCIPITAL LOW-GRADE ASTROCYTOMA

OBJECTIVE

Determine the feasibility and preliminary utility of a novel approach to intraoperative brain mapping guided by visualization of electrocorticography (ECoG) heat maps.

METHODS

A 39-year-old male with a biopsy-proven left posterior temporal and occipital WHO grade II IDH-mutant astrocytoma underwent awake craniotomy with intraoperative language mapping. Language mapping utilized a dual iPad stimulus presentation system (NeuroMapper) coupled to a portable real-time neural signal processing system capable of both recording cortical activity and delivering direct cortical stimulation in a closed-loop fashion. An ECoG grid (4x8 with 1cm pitch) which covered the majority of the left temporal lobe was used to assess oscillatory cortical activity during administration of language paradigms including object, action, auditory descriptive, and written descriptive naming. ECoG recording and cortical stimulation were synchronized with stimulus presentation via a photosensor attached to the patient-facing tablet. Gamma band modulations in response to language paradigms at each electrode were processed in real-time and visualized as heat maps in MATLAB/Simulink. Following recording and visualization, bipolar direct cortical stimulation from the grid was conducted for each neighboring electrode pair (up to an intensity of 6 mA) during administration of language tasks.

RESULTS

Despite mild fluent aphasia, a large set of reliable baseline stimuli were obtained for the language mapping paradigms. All naming paradigms resulted in strongest heat map activation at electrode 12 located in the anterior to mid superior temporal gyrus. During stimulation, consistent speech arrest was observed across all paradigms when stimulating electrode pair 11-12, indicating good correspondence with ECoG heat map recordings. Additionally, this region corresponded well with posterior language network representation via resting-state fMRI.

CONCLUSION

Intraoperative real-time visualization of task-based ECoG gamma band modulation is feasible and may help identify targets for direct cortical stimulation. If validated, this may improve the efficiency and accuracy of intraoperative language mapping.

Validation of Non-invasive Language Mapping Modalities for Eloquent Tumor Resection: A Pilot Study

Many studies have established a link between extent of resection and survival in patients with gliomas. Surgeons must optimize the oncofunctional balance by maximizing the extent of resection and minimizing postoperative neurological morbidity. Preoperative functional imaging modalities are important tools for optimizing the oncofunctional balance. Transcranial magnetic stimulation (TMS) and functional magnetic resonance imaging (fMRI) are non-invasive imaging modalities that can be used for preoperative functional language mapping. Scarce data exist evaluating the accuracy of these preoperative modalities for language mapping compared with gold standard intraoperative data in the same cohort. This study compares the accuracy of fMRI and TMS for language mapping compared with intraoperative direct cortical stimulation (DCS). We also identified significant predictors of preoperative functional imaging accuracy, as well as significant predictors of functional outcomes. Evidence from this study could inform clinical judgment as well as provide neuroscientific insight. We used geometric distances to determine copositivity between preoperative data and intraoperative data. Twenty-eight patients were included who underwent both preoperative fMRI and TMS procedures, as well as an awake craniotomy and intraoperative language mapping. We found that TMS shows significantly superior correlation to intraoperative DCS compared with fMRI. TMS also showed significantly higher sensitivity and negative predictive value than specificity and positive predictive value. Poor cognitive baseline was associated with decreased TMS accuracy as well as increased risk for worsened aphasia postoperatively. TMS has emerged as a promising preoperative language mapping tool. Future work should be done to identify the proper role of each imaging modality in a comprehensive, multimodal approach to optimize the oncofunctional balance.

CNTM-04. Alterations in structural connectomic properties associated with neurocognitive changes following glioma resection

BACKGROUND

Patients with brain tumors often experience decline in neurocognitive functioning (NCF) following surgical tumor resection. Connectomic studies have begun to uncover how abnormalities to underlying cerebral networks contribute to NCF deficits; however, few studies have investigated relationships between pre- to postoperative changes in structural connectomics and NCF.

METHODS

Fifteen right-handed adults with left perisylvian tumors underwent MRI of the brain with diffusion tensor imaging (DTI) and neuropsychological assessment before and after awake tumor resection. Graph theoretical analysis was applied to DTI-derived connectivity matrices to calculate structural network properties. Structural network properties and NCF measures were compared across the pre- to postoperative periods with matched pairs Wilcoxon signed-rank tests. Associations between pre- to postoperative change in network properties and change in NCF were determined with Spearman rank-order correlations (ρ).

RESULTS

Nearly 90% of the sample showed postoperative decline on 1 or more NCF measures. Significant postoperative NCF decline was found across measures of verbal memory, processing speed, executive functioning, receptive language, and the Clinical Trial Battery Composite (CTB COMP) index. Regarding connectomic properties, significant postoperative changes were observed in global and local efficiency, characteristic path length, clustering coefficient, betweenness centrality, and assortativity, with medium effect sizes. Significant associations (ρ = .59 to .62, all p < .05) were observed between changes in aspects of NCF and connectomic properties.

CONCLUSIONS

Decline in NCF was common following resection and some postoperative outcomes were associated with changes in structural connectomic properties following surgery.

Neurocognition and Health-Related Quality of Life Among Patients with Brain Tumors

Patients with brain tumors experience great symptom burden across various domains of functioning, with associated decreases in health-related quality of life and general well-being. Impaired neurocognitive functioning is among the primary concerns of these patients. Unfortunately, most patients will experience such impairment at some point in the disease. However, impaired neurocognitive functioning, symptom burden, and well-being vary according numerous patient-, tumor-, and treatment-related factors. Recent work has furthered our understanding of these contributors to patient functioning and health-related quality of life and also points to various potential targets for prevention and intervention strategies, though more efficacious treatments remain needed.

The role of resting-state functional MRI for clinical preoperative language mapping

Background

Task-based functional MRI (tb-fMRI) is a well-established technique used to identify eloquent cortex, but has limitations, particularly in cognitively impaired patients who cannot perform language paradigms. Resting-state functional MRI (rs-fMRI) is a potential alternative modality for presurgical mapping of language networks that does not require task performance. The purpose of our study is to determine the utility of rs-fMRI for clinical preoperative language mapping when tb-fMRI is limited.

Methods

We retrospectively reviewed 134 brain tumor patients who underwent preoperative fMRI language mapping. rs-fMRI was post-processed with seed-based correlation (SBC) analysis, when language tb-fMRI was limited. Two neuroradiologists reviewed both the tb-fMRI and rs-fMRI results. Six neurosurgeons retrospectively rated the usefulness of rs-fMRI for language mapping in their patients.

Results

Of the 134 patients, 49 cases had limited tb-fMRI and rs-fMRI was post-processed. Two neuroradiologists found rs-fMRI beneficial for functional language mapping in 41(84%) and 43 (88%) cases respectively; Cohen’s kappa is 0.83, with a 95% confidence interval (0.61, 1.00). The neurosurgeons found rs-fMRI “definitely” useful in 26 cases (60%) and “somewhat” useful in 13 cases (30%) in locating potential eloquent language centers of clinical interest. Six unsuccessful rs-fMRI cases were due to: head motion (2 cases), nonspecific functionality connectivity outside the posterior language network (1 case), and an unknown system instability (3 cases).

Conclusions

This study is a proof of concept that shows SBC rs-fMRI may be a viable alternative for clinical language mapping when tb-fMRI is limited.

Exposure of Allan Hills 84001 and other achondrites on the Antarctic ice

The enrichment of F on Antarctic meteorites is the result of their exposure to the atmosphere, and its measurement allows a subdivision of the terrestrial age into a duration of exposure on the ice and the time a meteorite was enclosed by the ice. In many cases, the periods of surface exposure are only small fractions of the terrestrial ages of meteorites collected in Antarctica. The enrichment of F on the surfaces of Antarctic achondrites was investigated by means of nuclear reaction analysis (NRA): scanning proton beams with an energy of 2.7 and 3.4 MeV were used to induce the reactions 19F(p, alpha gamma)16O and 19F(p,p gamma)19F, respectively. Gamma signals proportional to the F content were measured. The following Antarctic achondrites were investigated: Martian meteorite ALH 84001; diogenite ALHA77256; the eucrites ALHA81011 and ALHA78132; and in addition, the H5 chondrite ALHA79025. For ALH 84001, our data indicate a period of exposure on the ice of <500 years. Thus, this specimen was enclosed in the ice >95% of its terrestrial age of 13 000 years.

Differential expression and biological activity of the heparin-binding growth-associated molecule (HB-GAM) in lung cancer cell lines

The growth of human lung cancer cells is regulated positively and negatively by a variety of growth factors through autocrine as well as paracrine mechanisms. In the present report, we studied the differential role and expression of a neuropolypeptide growth factor in 26 lung cancer cell lines. Expression of the heparin-binding growth-associated molecule (HB-GAM) in 12 small cell lung cancer (SCLC) cell lines was compared to that in 14 non-small cell lung cancer (NSCLC) cell lines. HB-GAM mRNA was expressed in 9 of 12 SCLC and 3 of 14 NSCLC cell lines as determined by RT-PCR analyses. Normal human bronchial epithelial cells were used as negative controls. All cell lines which expressed HB-GAM mRNA produced HB-GAM protein as well. Western blot analysis showed that the tumor cells secreted HB-GAM into the media. HB-GAM, purified from lung cancer cell lines, exerted biological activity on fibroblasts, endothelial cells and SW13 cells as determined by thymidine incorporation and soft agar cloning assays. In addition, the biological activity of HB-GAM was blocked by a specific antibody in a dose-dependent way. Our findings suggest that HB-GAM may serve as a marker for SCLC cell lines and that it may function as a paracrine growth factor in human lung cancer. HB-GAM may be a further member of the network of growth factors involved in proliferation, angiogenesis and metastasis of lung tumors.

Nuclear localization of insulin-like growth factor binding protein 3 in a lung cancer cell line

Considerable evidence exists that lung cancer cell lines produce large amounts of insulin-like growth factor-binding proteins (IGFBPs). In addition, these cells are subject to an autocrine or paracrine growth control by insulin-like growth factors (IGFs). We now demonstrate by immunocytochemistry with IGFBP-3 antibodies that nuclei of a lung cancer cell line distinctly immunostain for IGFBP-3. This finding led us to investigate in more detail the localization of this protein that, to date, had only been known to occur extracellularly. Ligand blotting revealed that purified nuclear extracts contain a 43,000-Da IGFBP which can bind [I125]IGF-I. By Western blot this protein was identified as IGFBP-3. Thus, our data are consistent with the results of a previous structural study predicting a nuclear localization for IGFBP-3. Moreover, our findings raise the possibility that nuclear IGFBP-3 is functional and involved in the pathogenesis of lung cancer.

Insulin-like growth factors stimulate the release of insulin-like growth factor-binding protein-3 (IGFBP-3) and degradation of IGFBP-4 in nonsmall cell lung cancer cell lines

Insulin-like growth factors (IGFs) are potent mitogens for lung cancer cells. Their proliferative activity is influenced by their binding proteins (IGFBPs). We report here on the regulatory effects of IGF-I and IGF-II on the production and release of IGFBPs by nonsmall cell lung cancer cell lines (NSCLC). The nine NSCLC cell lines used in this study showed messenger ribonucleic acid (mRNA) expression of all six IGFBPs known, as determined by PCR, and protein secretion of IGFBP-1, -2, -3, -4, and -5, as analyzed by Western immunoblots. The addition of IGFs to a serum-free medium showed divergent effects on IGFBP-3 and IGFBP-4 levels in a conditioned medium (CM). IGF-I and IGF-II, but not insulin, led to a much higher concentration of IGFBP-3 in the CM of all tested NSCLC cell lines, whereas the level of immunologically detected membrane-associated IGFBP-3 was decreased. Furthermore, Northern analysis of mRNA isolated from A549 revealed that IGFBP-3 specific mRNA was not changed by IGF-I or IGF-II, suggesting that the IGF-induced effects on IGFBP-3 depend on the release of cell-associated IGFBP-3. In contrast, IGFBP-4 levels were diminished by increasing concentrations of IGFs in the CM of the NSCLCs A549, NCI-H157, and U1752, with no response to insulin or the IGF-I analog, whereas IGFBP-4-specific mRNA was not changed by IGF-I or IGF-II, as determined by Northern analysis. The same effects were seen in a cell-free system after incubation of the CM with IGFs. The decrease in IGFBP-4 concentrations was prevented by coincubation of the CM with the IGFs and either ethylenediamine tetraacetate or 1,10-phenanthrolene, but not with other protease inhibitors. We suggest that IGFs may either activate an IGFBP-4-specific metalloprotease present in NSCLC CM or that the binding of IGFs to IGFBP-4 may enhance the susceptibility of IGFBP-4 to proteolytic degradation. Based on these data, we present evidence that IGFs may regulate their own availability both by releasing IGFBP-3 from cell membrances and through proteolytic degradation of IGFBP-4.

Specific bradycardic agents. 1. Chemistry, pharmacology, and structure-activity relationships of substituted benzazepinones, a-new class of compounds exerting antiischemic properties

Structural modification of the calcium-antagonist verapamil (1) by replacement of the lipophilic alpha-isopropylacetonitrile moiety by various heterocyclic ring systems has led to a new class of cardiovascular compounds which are characterized by a specific bradycardic activity. These agents reduce heart rate without binding to classical calcium channels or beta-adrenoceptors, interacting instead specifically with structures at the sino atrial node. Therefore they have also been termed sinus node inhibitors. The prototype falipamil (2) has been submitted to further optimization mainly by manipulation of the phthalmidine moiety. This has resulted in a second generation of specific bradycardic agents with increased potency and selectively and prolonged duration of action represented by the benzazepinone-derivative UL-FS 49 (4). Structure-activity relationships within this novel class of compounds have revealed a marked dependence of activity on the substitution pattern of the aromatic rings, the nature of the central nitrogen atom, and the length of the connecting alkyl chains. The crucial role of the benzazepinone ring for bradycardic activity can be best explained by its special impact on the overall molecular conformation.

Preparation and biological activity of new substituted antimalarial diaminodiphenylsulfones

Starting from 4,4'-diamino-diphenylsulfone (DDS) as a lead structure, new 2-substituted analogues as well as new 2-substituted 4-alkylamino-4'-amino diphenylsulfones have been designed and synthetized in different ways. This has led to compounds the inhibitory activity of which against 7,8-dihydropteroic acid synthase of plasmodia and mycobacteria is clearly superior to that of sulfadoxine and in most cases to that of DDS. Of special interest is 4'-amino-4-n-propylamino-2-methyl-diphenylsulfone. Together with inhibitors of 7,8-dihydrofolate reductase in vitro and in vivo it possesses a marked synergistic inhibitory activity against plasmodia. In contrast to DDS in doses up to 200 mg/kg p.o. (cat) no methemoglobin formation is observed. The compound has been selected for further studies.