Perifocal Edema in Patients with Meningioma is Associated with Impaired Whole-Brain Connectivity as Detected by Resting-State fMRI

BACKGROUND AND PURPOSE

Meningiomas are intracranial tumors that usually carry a benign prognosis. Some meningiomas cause perifocal edema. Resting-state fMRI can be used to assess whole-brain functional connectivity, which can serve as a marker for disease severity. Here, we investigated whether the presence of perifocal edema in preoperative patients with meningiomas leads to impaired functional connectivity and if these changes are associated with cognitive function.

MATERIALS AND METHODS

Patients with suspected meningiomas were prospectively included, and resting-state fMRI scans were obtained. Impairment of functional connectivity was quantified on a whole-brain level using our recently published resting-state fMRI-based marker, called the dysconnectivity index. Using uni- and multivariate regression models, we investigated the association of the dysconnectivity index with edema and tumor volume as well as cognitive test scores.

RESULTS

Twenty-nine patients were included. In a multivariate regression analysis, there was a highly significant association of dysconnectivity index values and edema volume in the total sample and in a subsample of 14 patients with edema, when accounting for potential confounders like age and temporal SNR. There was no statistically significant association with tumor volume. Better neurocognitive performance was strongly associated with lower dysconnectivity index values.

CONCLUSIONS

Resting-state fMRI showed a significant association between impaired functional connectivity and perifocal edema, but not tumor volume, in patients with meningiomas. We demonstrated that better neurocognitive function was associated with less impairment of functional connectivity. This result shows that our resting-state fMRI marker indicates a detrimental influence of peritumoral brain edema on global functional connectivity in patients with meningiomas.

Antithrombotic treatment and outcome after endovascular treatment and acute carotid artery stenting in stroke patients with atrial fibrillation

Background

Oral anticoagulation (OAC) is the mainstay of secondary prevention in ischemic stroke patients with atrial fibrillation (AF). However, in AF patients with large vessel occlusion stroke treated by endovascular therapy (ET) and acute carotid artery stenting (CAS), the optimal antithrombotic medication remains unclear.

Methods

This is a subgroup analysis of the German Stroke Registry—Endovascular Treatment (GSR-ET), a prospective multicenter cohort of patients with large vessel occlusion stroke undergoing ET. Patients with AF and CAS during ET were included. We analyzed baseline and periprocedural characteristics, antithrombotic strategies and functional outcome at 90 days.

Results

Among 6635 patients in the registry, a total of 82 patients (1.2%, age 77.9 ± 8.0 years, 39% female) with AF and extracranial CAS during ET were included. Antithrombotic medication at admission, during ET, postprocedural and at discharge was highly variable and overall mortality in hospital (21%) and at 90 days (39%) was high.

Among discharged patients (n = 65), most frequent antithrombotic regimes were dual antiplatelet therapy (DAPT, 37%), single APT + OAC (25%) and DAPT + OAC (20%). Comparing DAPT to single or dual APT + OAC, clinical characteristics at discharge were similar (median NIHSS 7.5 [interquartile range, 3–10.5] vs 7 [4–11], p = 0.73, mRS 4 [IQR 3–4] vs. 4 [IQR 3–5], p = 0.79), but 90-day mortality was higher without OAC (32 vs 4%, p = 0.02).

Conclusions

In AF patients who underwent ET and CAS, 90-day mortality was higher in patients not receiving OAC.

Registration: https://www.clinicaltrials.gov; Unique identifier: NCT03356392.

Supplementary Information

The online version contains supplementary material available at 10.1186/s42466-022-00207-7.

Basal Ganglia versus Peripheral Infarcts: Predictive Value of Early Fiber Alterations

BACKGROUND AND PURPOSE

Impairment of fiber integrity of the corticospinal tract in the subacute and chronic phases after ischemic stroke has been linked to poor motor outcome. The aim of the study was an assessment of fiber integrity in the acute poststroke phase and an evaluation of its association with the clinical course dependent on the infarction pattern (subtypes: peripheral versus basal ganglia infarction).

MATERIALS AND METHODS

All patients who underwent mechanical recanalization of a large-vessel occlusion in the anterior circulation and postinterventional DTI were included (n = 165). The fractional anisotropy index of the patient-specific corticospinal tract within the posterior limb of the internal capsule was correlated to clinical parameters (NIHSS scores/mRS at 90 days), and the interaction of stroke subtype (peripheral infarcts versus basal ganglia infarction) was tested in a moderation analysis.

RESULTS

The fractional anisotropy index was reduced in the acute poststroke phase with a correlation to clinical presentation, especially in case of peripheral infarcts (eg, with the NIHSS motor subscore: r = -0.4, P < .001). This correlation was absent for basal ganglia infarction (r = -0.008, P > .05). There was a significant association between the fractional anisotropy index and clinical outcome (mRS after 90 days, P < .01), which is moderated by stroke subtype with significant effects only for peripheral infarcts.

CONCLUSIONS

Corticospinal tract abnormalities can be observed in the early stage after mechanical recanalization and have prognostic capacity. This finding increases the clinical value of early DTI imaging parameters. Because the effects observed were limited to peripheral infarcts, further and longitudinal evaluation of fiber integrities within basal ganglia infarction is required.

A short history of thrombectomy - Procedure and success analysis of different endovascular stroke treatment techniques

Background

The historical development of interventional stroke treatment shows a wide variation of different techniques and materials used. Thus, the question of the present work is whether the technical and procedural differences of thrombectomy techniques lead to different technical and clinical results.

Methods and results

Analysis of a mixed retrospective/prospective database of all endovascular treated patients with an occlusion of the Carotid-T or M1 segment of the MCA at a single comprehensive stroke center since 2008. Patients were classified regarding the technical approach used. Six hundred sixty-eight patients were available for the final analysis. Reperfusion rates ranged between 56% and 100% depending on the technical approach. The use of balloon guide catheters and most recently the establishment of combination techniques using balloon guide catheters, aspiration catheters and stent retrievers have shown a further significant increase in the rates of successful recanalization, full recanalization and first-pass recanalization. Additionally, the technical development of interventional techniques has led to a subsequent drop in complications, embolization into previously unaffected territories in particular.

Conclusion

Technical success of MT has improved substantially over the past decade owing to improved materials and procedural innovations. Combination techniques including flow modulation have emerged to be the most effective approach and should be considered as a standard of care.

Level of evidence: Level 3, retrospective study.

Thrombus Histology of Basilar Artery Occlusions : Are There Differences to the Anterior Circulation?

BACKGROUND

For patients with acute vessel occlusions of the anterior circulation histopathology of retrieved cerebral thrombi has been reported to be associated to stroke etiology. Due to the relatively small incidence of posterior circulation stroke, exclusive histopathologic analyses are missing for this subgroup. The aim of the study was to investigate thrombus histology for patients with basilar artery occlusions and uncover differences to anterior circulation clots with respect to underlying etiology.

METHODS

A total of 59 basilar thrombi were collected during intracranial mechanical recanalization and quantitatively analyzed in terms of their relative fractions of the main constituents, e.g. fibrin/platelets (F/P), red (RBC) and white blood cells (WBC). Data were compared to histopathological analyses of 122 thrombi of the anterior circulation with respect to underlying pathogenesis.

RESULTS

The composition of basilar thrombi differed significantly to thrombi of the anterior circulation with an overall higher RBC amount (median fraction in % (interquartile range):0.48 (0.37-0.69) vs. 0.37 (0.28-0.50), p < 0.001) and lower F/P count (0.45 (0.21-0.58) vs. 0.57 (0.44-0.66), p < 0.001). Basilar thrombi composition did not differ between the different etiological stroke subgroups.

CONCLUSION

The results depict a differing thrombus composition of basilar thrombi in comparison to anterior circulation clots with an overall higher amount of RBC. This may reflect different pathophysiologic processes between anterior and posterior circulation thrombogenesis, e.g. a larger proportion of appositional thrombus growth in the posterior circulation.

Stroke Etiology Modifies the Effect of Endovascular Treatment in Acute Stroke

Background and Purpose—

Stroke etiology drives thrombus composition. We thus hypothesized that endovascular treatment shows different efficacy in cardioembolic versus noncardioembolic large-vessel occlusions (LVOs).

Methods—

Procedural characteristics, grade of reperfusion, and functional outcome at discharge and 90 days were compared between patients with cardioembolic versus noncardioembolic LVO from the GSR-ET (German Stroke Registry–Endovascular Treatment; n=2589). To determine associations with functional outcome, adjusted odds ratios and 95% CIs were calculated using ordinal multivariable logistic regression models adjusting for potential baseline confounder variables.

Results—

Endovascular treatment of cardioembolic LVO had a higher rate of successful reperfusion (85.6% versus 81.0%; P =0.002) and a higher rate of complete reperfusion after a single thrombectomy pass (45.7% versus 38.1%; P <0.001) compared with noncardioembolic LVO. Cardioembolic LVO was associated with better functional outcome at discharge (adjusted odds ratio, 1.61 [95% CI, 1.37–1.88]) and 90 days (adjusted odds ratio, 1.29 [95% CI, 1.09–1.53]). In mediation analysis, reperfusion explained 47% of the effect of etiology on functional outcome at discharge.

Conclusions—

These results provide evidence for higher efficacy of endovascular treatment in cardioembolic LVO compared with noncardioembolic LVO.

Microstructural Integrity of Salvaged Penumbra after Mechanical Thrombectomy

BACKGROUND AND PURPOSE

There are sparse data on the microstructural integrity of salvaged penumbral tissue after mechanical thrombectomy of large-vessel occlusions. The aim of the study was to analyze possible microstructural alteration in the penumbra and their association with clinical symptoms as well as angiographic reperfusion success in patients undergoing mechanical thrombectomy.

MATERIALS AND METHODS

All patients who underwent mechanical thrombectomy for large-vessel occlusions in the anterior circulation and who received an admission CT perfusion together with postinterventional DTIs were included (n = 65). Angiographic reperfusion success by means of modified Thrombolysis in Cerebral Infarction (mTICI) scale and clinical outcome were recorded. Microstructural integrity was assessed by DTI evaluating the mean diffusivity index within the salvaged gray matter of the former penumbra.

RESULTS

The mean diffusivity index was higher in completely recanalized patients (mTICI 3: -0.001 ± 0.034 versus mTICI <3: -0.030 ± 0.055, P = .03). There was a positive correlation between the mean diffusivity index and NIHSS score improvement (r = 0.49, P = .003) and the mean diffusivity index was associated with midterm functional outcome (r = -0.37, P = .04) after adjustment for confounders. In mediation analysis, the mean diffusivity index and infarction growth mediated the association between reperfusion success and clinical outcomes.

CONCLUSIONS

The macroscopic salvaged penumbra included areas of microstructural integrity changes, most likely related to the initial hypoperfusion. These abnormalities were found early after mechanical thrombectomy, were dependent on angiographic results, and correlated with the clinical outcome. When confirmed, these findings prompt the evaluation of therapies for protection of the penumbral tissue integrity.

Etiology of recurrent large vessel occlusions treated with repeated thrombectomy

BACKGROUND

Repeated mechanical thrombectomy for acute stroke treatment in individual patients has been proven feasible. However, less is known about the etiology of recurrent vessel occlusions after prior thrombectomy. We aimed to understand if the etiology of such recurrent events differs from the first stroke.

METHODS

Retrospectively, we identified all patients at our center who received a repeated mechanical thrombectomy between 2007 and 2019. Clinical data were retrieved from medical records. Etiology of stroke was evaluated retrospectively, and angiographic studies were revisited.

RESULTS

Twenty-three patients (1.5%) were identified. Median age was 68 years (IQR 56-77). Median NIHSS at first admission was 11 points (IQR 5-15). In nine cases (39.1%), the recurrent vessel occlusion was located exactly at the same position as the prior occlusion. Overall, five (21.7%) patients had a remarkable extracranial pathology as likely cause of stroke recurrence. In 16 patients (69.6%), the etiology of the first stroke and its recurrence was considered as likely being the same, mostly of cardioembolic or unknown origin. In the seven remaining patients (30.4%), the cause of stroke possibly differed from the first event, with five patients (21.7%) having a postinterventional intracranial intimal lesion as possible cause of stroke.

CONCLUSION

Incidence of repeated thrombectomy was low. However, the high number of patients with known origin of stroke etiology raises the question how their monitoring may be optimized. The number of patients with remarkable extracranial pathologies or intracranial endothelial lesions supports current clinical practice to pay attention to final angiographic series.

Entropy Evolution in the Magnetic Phases of Partially Frustrated CePdAl

In the heavy-fermion metal CePdAl, long-range antiferromagnetic order coexists with geometric frustration of one-third of the Ce moments. At low temperatures, the Kondo effect tends to screen the frustrated moments. We use magnetic fields B to suppress the Kondo screening and study the magnetic phase diagram and the evolution of the entropy with B employing thermodynamic probes. We estimate the frustration by introducing a definition of the frustration parameter based on the enhanced entropy, a fundamental feature of frustrated systems. In the field range where the Kondo screening is suppressed, the liberated moments tend to maximize the magnetic entropy and strongly enhance the frustration. Based on our experiments, this field range may be a promising candidate to search for a quantum spin liquid.

The pREset Stent Retriever for Endovascular Treatment of Stroke Caused by MCA Occlusion: Safety and Clinical Outcome

PURPOSE

The purpose of this study was to analyze the safety and efficacy of the pREset device, a stent retriever system, for endovascular mechanical thrombectomy (MT) in acute ischemic stroke (AIS) after middle cerebral artery (MCA) occlusion.

METHODS

Retrospectively, 48 consecutive patients (mean age ± standard deviation, 71.0 ± 11.9 years; 24 women) treated for acute MCA occlusion using pREset solely or in combination with other MT devices were identified. Recanalization success was evaluated using the modified thrombolysis in cerebral infarction score (TICI), and complications were detected by 24-h follow-up computed tomography or magnetic resonance imaging. MCA anatomy was assessed in angiograms. Clinical outcome was evaluated with National Institutes of Health Stroke Scale (NIHSS) score at admission and discharge, and modified Rankin scale (mRS) score at discharge and follow-up.

RESULTS

Successful recanalization (TICI 2b/3) was achieved in 39 patients (81.3 %). Rate of procedure-related complications was 8.3 %. In four patients, a subarachnoid hemorrhage occurred (8.3 %), and parenchymal hematoma was detected in four patients (8.3 %). None of those events was associated with clinical deterioration. MCA curvature significantly influenced recanalization success (P < 0.005). Successful recanalization correlated significantly with lower NIHSS scores and favorable clinical outcome (mRS score 0-2) at discharge (P < 0.05). Mortality within 90 days was significantly lower in patients with TICI 2b/3 (P < 0.005).

CONCLUSIONS

High recanalization rates, low complication rates, and a significantly improved outcome after successful recanalization strongly suggest that MT with pREset is an adequate therapy for AIS after MCA occlusion. Vessel curvature is a significant determining factor for recanalization success.

223 GENERATION OF INTERSPECIES CHIMERAS BETWEEN PRIMATE INDUCED PLURIPOTENT STEM CELLS AND PORCINE PARTHENOGENETIC EMBRYOS

The availability of human induced pluripotent stem cell (hiPSC) paves the way to generate regenerative tissue or organs from patient’s own stem cells. The production of chimeric piglets carrying organs that are entirely derived from human stem cells, or at least have a high contribution of human cells or tissues, could be used as a new tissue or an organ replacement in the future treatment of the patients. Here, we produced porcine-nonhuman primate chimeric embryos to assess the feasibility of the potential use of human iPSC for production of human stem cell-derived organs in pigs. Because in vitro culture conditions for cynomolgus monkey iPSC and porcine blastocysts are different, we first identified an effective in vitro culture system for porcine blastocysts and monkey iPSC. We compared blastocyst rates (Days 7 and 8) and number of cells of porcine parthenogenetic blastocysts (Day 8) cultured in 8 different monkey iPSC media and in porcine zygote medium 3 (PZM-3). The best developmental rates of porcine blastocysts were achieved in Knockout DMEM+20% serum replacement monkey medium (iPS 20% medium; N = 65, n = 3). The number of blastocysts on Day 8 cultured in iPS 20% medium was significantly higher (91%; P < 0.05) than in the commonly used porcine PZM-3 medium (65%). We found significantly fewer (P < 0.05) degenerate porcine embryos on Day 8 after culture in iPS 20% medium (9%) compared to PZM-3 (35%). The number of nuclei per blastocyst in iPS 20% medium (88 nuclei; N = 30, n = 3) was significantly higher (P < 0.0001) than in the PZM-3 medium (57 nuclei; N = 54, n = 3). Therefore, we decided to use iPS 20% medium for culture of porcine blastocysts injected with monkey iPSC. Thereafter, we injected clusters of 10 to 15 monkey iPSC transgenic with AAVS1-CAG-Venus into porcine parthenogenetic embryos from Days 4 and 6. Interspecies chimeras were cultured in iPS 20% medium for 24 (for Day 6 embryos) or 48 h (for Day 4 embryos) and observed by confocal microscopy to determine the proportion of Venus-expressing monkey iPSC in porcine embryos. Approximately 37% of blastocysts contained Venus-positive cells after injection of Day 6 embryos (N = 133, n = 4). In contrast, injection into porcine embryos from Day 4 resulted in 73% of Venus-positive blastocysts (N = 69, n = 3). Finally, we investigated proliferation and survival of monkey iPSC in interspecies chimeras after blastocyst plating onto murine fibroblasts. Chimeric blastocyst outgrowth resulted in Venus-expressing monkey iPSC proliferating over 1 week in culture. Outgrowths of all chimeric blastocysts established distinct but separate monkey and porcine stem cell colonies. Here, we optimized the culture conditions for an in vitro interspecies chimera assay in which monkey iPSC are able to survive in porcine embryos. Integration of monkey iPSC to host inner cell mass is relevant for the further contribution to the embryo development. Therefore, to verify this, analysis of cell-cell connection between monkey iPSC and porcine blastocysts and experiments using vivo-derived embryos are currently underway.

101 TOWARDS OPTIMAL IN VITRO CULTURE CONDITIONS FOR PIG-MONKEY AGGREGATION CHIMERAS

Induced pluripotent stem cells (iPSCs) are promising for developing novel cell-based medical treatments. One potential use of iPSCs is for xenotransplantation via production of chimeric organisms. The generation of organs originated from the iPSCs of one individual in a foreign organism could allow the production of immune compatible organ transplants. One of the major problems down this road is to define the different nutrient needs of chimeric embryos (i.e. iPSCs and the host embryos). Here, we evaluated different media for supporting development of chimeric embryos consisting of parthenogenetic porcine embryos and iPS cells, either from pig or nonhuman primate, to identify the optimal medium conditions for pig-monkey aggregation chimeras. First, we cultured 3-day-old porcine parthenogenetic embryos in porcine zygote medium (PZM), iPSC-medium, and mixtures of the two media to identify the most suitable culture conditions. Three-day-old parthenogenetic embryos developed poorly in pure iPSC-medium (6.3% blastocyst rate), but grew in a mixture of PZM and iPSC medium. The best results were achieved with PZM and PZM with 10% or 25% iPSC medium (38.8% and 30% blastocyst rates, respectively). Next, we checked aggregation results of chimeric embryos produced with two different iPSC lines in the respective media (PZM, PZM+10% iPSC medium, PZM+25% iPSC medium). The porcine iPSC line (piPSC) and cynomolgus monkey iPSC line (ciPSC) carry fluorescent markers (piPSC: GFP, ciPSC: venus), thus facilitating detection of integration into the host embryos. After aggregation of iPS cells between two Day-3 parthenogenetic embryos (sandwich technique), blastocyst rates at Day 6 were determined (see Table 1). While culture in PZM allowed for the highest blastocyst rate (>40%), the iPS cell participation was very low (0–11.1%). Cultivation in PZM+25% iPS medium was compatible with a high rate of embryo-iPSC chimeras (50–100%), but with a low blastocyst rate (7.7–16.7%). Possibly, the iPS cells proliferate more rapidly than blastomeres and the embryo is overgrown. The best results were obtained in medium mixture PZM+10% iPSC medium (25–40% blastocyst rate with 66.7–100% iPS cell participation). These results show that supplementation of the basic culture medium with 10% iPSC medium yields high blastocyst rates for chimeric embryos, and also ensures much higher iPS cell participation. This improves the use of 3-day-old embryos in aggregation chimeras. Table 1.Development of parthenogenetic porcine embryo aggregates with porcine (p) or cynomolgus monkey (c) iPS cells

Fate of the penumbra after mechanical thrombectomy

BACKGROUND AND PURPOSE

In acute stroke, CTP is often used to visualize the endangered brain areas, including the ischemic core and the penumbra. Our goal was to assess the evolution of the infarct after mechanical thrombectomy and to analyze the interventional factors determining the fate of the penumbra.

MATERIALS AND METHODS

All patients receiving mechanical thrombectomy in the anterior circulation and receiving CTP beforehand were identified. The infarct volume was specified. The clinical parameters, outcome, and interventional results were correlated with the CTP and the final infarct size.

RESULTS

In total, 73 patients were included. After mechanical thrombectomy, 78.1% reached a TICI score of 3/2b. The final infarct volume was significantly smaller, with a TICI score of 3/2b compared with less sufficient recanalization (19.60 ± 3 cm(3) versus 38.1 ± 9 cm(3); P < .001). After TICI 3/2b recanalization, 81% ± 5.2% of the potential infarct size (calculated as the sum of infarct core and penumbra) could be rescued. In patients with TICI scores of 2a or worse, only 39 ± 28.3 were salvaged (P < .001). The Alberta Stroke Program Early CT Score after successful recanalization TICI score of 3/2b resulted in a decline of 1.9 ± 1.4 compared with the significantly higher degradation score of 3.7 ± 1.7 after recanalization, with a TICI score of 2a or worse. A recanalization TICI score of 3/2b resulted in an NIHSS improvement of 7.3 ± 0.8 NIHSS points, whereas a poorer recanalization improved on the NIHSS by only 2.5 ± 1.5 points (P < .01).

CONCLUSIONS

Mechanical thrombectomy is a potent method to rescue large areas of penumbra in acute stroke.

Nutrition risk factors among home delivered and congregate meal participants: need for enhancement of nutrition education and counseling among home delivered meal participants

OBJECTIVE

The short-term impact of nutrition education and counseling intervention on nutrition risk factors among home delivered (HDM) and congregate (CGM) meal participants using Nutrition Survey Risk Screening was studied.

DESIGN

A two-year intervention was conducted with 355 participants (n=259 CGM, n=96 HDM). Various nutrition behaviors that affect the nutrition risk score were compared.

SETTING

Congregate and home delivered meal locations in a northern county of New Jersey.

PARTICIPANTS

CGM and HDM participants in a northern county of New Jersey age 60 and older.

INTERVENTION

CGM participants received regular topical nutrition education and counseling in a classroom format with cooking demo, discussion, and handouts. The HDM participants only received the printed material (same handouts) and counseling by telephone.

MEASUREMENTS

Demographics, medical condition, risk factors data were collected. All participants completed the 12 items checklist Nutrition Survey Risk Screening. Nutritional behaviors assessed include number of meals eaten per day, servings of fruits and vegetables and nutrition risk score. A score of 6 or more points was defined as persons at high risk nutritionally. The impact of the intervention was evaluated using ANOVA/chi-square on Nutrition Survey Risk Screening.

RESULTS

Nutrition education and counseling intervention improved nutrition risk scores; 5.76 to 5.32 (p=0.14) in CGM, 8.1 to 6.1 (p<0.01) in HDM. A slight improvement in nutrition behaviors was noted: eating ≥ 2 meals in HDM (76 to 81.6 %, p= .310), eating ≥ 5 servings of fruits and vegetables in CGM (38 to 41.4 %, p=. 398).

CONCLUSION

Appropriate nutrition intervention for both HDM and CGM participants can improve health condition and delay chronic diseases. HDM participants need to be a primary focus for more effective nutrition education and counseling.

Stent angioplasty of intracranial stenosis: single center experience of 54 cases

PURPOSE

The aim of the study was to retrospectively evaluate the safety and efficacy of stent angioplasty of symptomatic intracranial stenosis in a single center experience.

MATERIALS AND METHODS

Between November 2006 and September 2009 a total of 54 stent angioplasties were performed in 49 patients and of these 46 were done for symptomatic intracranial high-grade (>70%) stenoses and 8 for complete vessel occlusions in acute stroke. All elective treatments were carried out with patients under antithrombotic/anticoagulant medication. Self-expandable stents were used in 42 cases and balloon-expandable stents in 12 cases.

RESULTS

Stent angioplasty was successful in 53 out of 54 cases (98%). Periprocedural complications occurred in 6 patients, including 2 dissections, 1 contrast-mediated toxic reaction and 1 thromboembolic event with transient neurological deficits but did not cause permanent neurological deficits, in any of the cases. Adverse events within 30 days after intervention occurred in 11 of the 49 patients (20.4%) of which 4 were scheduled patients (8.3%) and 7 were treated for acute stroke with complete vessel occlusions (87.5%). Overall there were 9 cases of restenosis (7 out of 9>90% stenoses and 2 complete vessel occlusions), 5 out of 9 were asymptomatic, 4 out of 9 had a transient ischemic attack and 1 developed a major stroke. Two complete in-stent thromboses were seen in acute stroke patients with initial complete occlusion within 24 h after recanalization. One restenosis and one complete occlusion occurred under double antiplatelet medication, 4 out of 9 restenoses occurred under aspisol medication and 3 out of 9 after antiplatelet medication was discontinued. In 2 out of 9 restenoses, balloon-expandable stents had been used, the remaining 7 had been treated with self-expanding stents, 5 out of 9 restenoses were treated by balloon-angioplasty alone, in 3 out of 9 an additional stent had to be placed and 1 asymptomatic occlusion was left untreated.

CONCLUSIONS

The results demonstrate the technical feasibility and satisfactory success rates of stent angioplasty in intracranial atherosclerotic stenoses. The procedural success rate was 98% and the overall rate of adverse events was 20.4%. The rate of adverse events was high in unstable patients (87.5%) treated without antiplatelet premedication, especially in the setting of an acute stroke. In stable patients the rate of adverse events was much lower (8.3%). Future development of dedicated stents and a better understanding of factors that predispose to restenosis may help to further decrease the rate of periprocedural and postprocedural adverse events thus helping to improve both short-term and long-term outcome after intracranial stent angioplasty.

Natural abiotic formation of furans in soil

Furan and its derivates are a potentially important, and little studied, class of volatile organic compounds of relevance to atmospheric chemistry. The emission of these reactive compounds has been attributed previously to biomass burning processes and biogenic sources. This paper investigates the natural abiotic formation of furans in soils, induced by the oxidation of organic matter by iron(III) and hydrogen peroxide. Several model compounds like catechol, substituted catechols, and phenols as well as different organic-rich soil samples were investigated for the release of furans. The measurements were performed with a purge and trap GC/MS system and the influence of hydrogen peroxide, reaction temperature, iron(III), pH, and reaction time on furan yield was determined. The optimal reaction turnover obtained with catechol was 2.33 microg of furan from 0.36 mg of carbon. Results presented in this paper show that a cleavage of catechol into a C2- and a C4-fragment occurs, in which the C4-fragment forms furan by integrating an oxygen atom stemming from H2O2. Furthermore, phenols could be transformed into catecholic structures under these Fenton-like conditions and also display the formation of furans. In conclusion, catalytic amounts of iron(III), the presence of hydrogen peroxide, and acidic conditions can be seen as the most important parameters required for an optimized furan formation.

Cervical dystonia in monozygotic twins: case report and review of the literature

We report on monozygotic male twins of German origin with early onset cervical dystonia. No other family members were affected. Although identical in age of onset and clinical course, there were phenotypic variations. While the second-born, more affected twin suffered from a symmetric retrocollis, the twin brother mainly presented with a spasmodic torticollis to the left. Dystonia remained focal in both siblings. A DYT1 gene deletion was excluded. Including our patients, hitherto only four twin pairs with idiopathic dystonia have been reported. Although dystonia in twins can be remarkably uniform in some cases, major differences in terms of disease progression, remissions, and disability may be found. These observations underline the role of inheritance in the pathogenesis of idiopathic dystonia but also indicate that some other factors contribute to the clinical presentation of dystonia.

Effects of glutathione peroxidase and catalase on hemolysis and methemoglobin modifications induced by photooxidized psoralen

Psoralen photooxidation products (POP products) were obtained by UVA irradiation (365 nm, 180-640 W/m2) of an aqueous psoralen solution with fluences of 0-800 kJ/m2. Preincubation of POP products with glutathione peroxidase (GSHPer) or catalase, as well as presence of catalase during UVA irradiation of the aqueous psoralen solution did not influence their hemolytic activity. However, both GSHPer and catalase inhibited POP-induced conversion of methemoglobin. This indicates that hydrogen peroxide and psoralen peroxides destructible by GSHPer, which are being produced during psoralen photooxidation, do not possess hemolytic activity. Furthermore, hydrogen peroxide does not appear to serve as an intermediate in the process of hemolysin formation. Hydrogen peroxide generated during psoralen photooxidation is apparently the main POP product responsible for MetHb conversion.

Invasive behaviour of human gliomas is mediated by interindividually different integrin patterns

BACKGROUND

Glioma invasion is still a major obstacle for successful therapy. In the past we could demonstrate that glioma invasion is mediated by different adhesion molecules of the integrin family. Here we investigated whether a common pattern of integrin profiles might be involved, potentially providing a therapeutical avenue.

MATERIAL AND METHODS

Multicellular spheroids were generated out of three human cell lines (GaMG, U373, U251) and from tumor biopsies of 9 human glioblastomas. After confrontation with rat brain aggregates, functional blocking antibodies against different integrin subunits (alpha 2, alpha 3, alpha v, alpha 1, alpha v beta 3, alpha v beta 5) or four different disintegrines (kistrin, echistatin, eristostatin, flavoridin) were added. Integrin patterns of the human cell lines/specimens were determined by FACScan or immunohistochemistry.

RESULTS

In cell lines, antibodies against alpha 2, alpha 3, alpha v and alpha v beta 5 effectively reduced invasion into rat brain aggregates. Little effect could be observed with the anti-beta 1- or with anti-alpha v beta 3- antibodies. In primary tumor specimens, however, a different invasion pattern in regard to its integrin dependency emerged with antibodies against the alpha 3-chain or the alpha v beta 3 integrin being the most effective. Invasion of primary tumor tissue into the brain aggregates was by far more aggressive compared to that of the cell lines. Accordingly, it was less influenced by integrin antibodies. The disintegrines affected migration of glioma cells on purified ECM substrates in a heterogeneous matter, but had no impact on tumor invasion into brain aggregates.

CONCLUSION

Although invasion of human gliomas is mediated by integrins, due to the heterogeneity of its dependency on different integrins this approach seems not to be appropriate to sufficiently alter glioma invasion in a therapeutical neuro-oncological setting.

Integration Of SiON waveguides and photodiodes on silicon substrates

Two methods of coupling integrated optical waveguides to photodetectors are investigated. As waveguides, SiON layers were deposited by low-pressure chemical vapor deposition on a thick isolation layer of thermally grown SiO(2) on silicon substrates. Lateral p-i-n diode photodetectors were fabricated by standard processing in the silicon substrates. Structures for end-fire and leaky-wave coupling were fabricated. Coupling efficiencies of up to 84% for end-fire and 88% for leaky-wave coupling were obtained. The fabrication steps are described, and the resulting optoelectrical behavior is discussed.

[Music improvisation with schizophrenic patients--a controlled study in the assessment of therapeutic effects]

The effects of a course of music therapy with free improvisation, consisting of 27 sessions over a period of 6 months, were examined in a controlled study of matched therapy and waiting group, each comprising 7 patients with a diagnosis of schizophrenia or schizoaffective psychosis. The psychopathologic picture having essentially remained unaltered on the measuring instrument used (Lorr scales), significant positive changes were found in the self-assessment questionnaires completed by the participants. Improvements in recreational and social behaviours could not be shown. The disease and reintegration processes took similarly positive courses in both groups, supported by the extensive range of psychiatric/psychotherapeutic services available in the Munich area. The improvising orientation of the music therapy course had mostly been approved of by the patients, it however also gave rise to a desire for more structuring and a more goal-directed therapeutic approach. A tendency towards the initial values, i.e. a deterioration, was stated in the therapy group at follow-up six months post-therapy.

Reticulocyte lipoxygenase changes the passive electrical properties of bovine heart submitochondrial particles

Purified reticulocyte lipoxygenase oxygenates the polyunsaturated phospholipids of sonified submitochondrial particles from bovine heart as measured by a burst of oxygen uptake. Over the frequency range of 0.5 to 100 MHz, the complex impedance of the submitochondrial particles as a function of the frequency before and after lipoxygenase attack was measured. From these data, the membrane capacity, the conductivity of the membrane and the conductivity inside the particles were calculated. Lipoxygenase action causes a 4-fold increase in the membrane capacity and a 2-fold increase in the membrane conductivity. Using the method of deformation of electric pulses, kinetic measurements were performed. In parallel to the changes of the passive electric properties, a partial inhibition of NADH oxidase and succinate oxidase was caused by the lipoxygenase attack. Oxygen uptake, changes of the passive electric properties and the inhibition of respiratory enzymes were prevented by lipoxygenase inhibitors. Owing to the high oxygen consumption produced by the lipoxygenase reaction, anaerobiosis was reached within the first 30 s in the closed chamber. Therefore, it must be concluded that the changes in passive electric properties and the inhibition of the respiratory enzymes are due to secondary anaerobic processes such as the hydroperoxidase reaction catalyzed by the lipoxygenase or a slow redistribution of peroxidized membrane lipids. The results are discussed in relation to the breakdown of mitochondria during the maturation process of red cells.