Associations of collagen type I α2 polymorphisms with the presence of intracranial aneurysms in patients from Germany.

OBJECTIVE: Subarachnoid hemorrhage from ruptured intracranial aneurysms is associated with a severe prognosis. Preventive treatment of unruptured intracranial aneurysms is possible and recommended. However, the identification of risk patients by genetic analyses is not possible because of lack of candidate genes. Collagen type I α2 (COL1A2) has been associated with the presence of aneurysms in patients from Japan, China, and Korea. In this study, we investigate whether COL1A2 is a possible aneurysm candidate gene in the German population. METHODS: Patients admitted with intracranial aneurysms to our department and collaborating departments were enrolled. Three single-nucleotide polymorphisms (SNPs) of the COL1A2 gene, namely rs42524 in exon 28, rs1800238 in exon 32, and rs2621215 in intron 46 were investigated using restriction enzymes and sequencing. HapMap data were used for comparison of allelic frequencies with the normal population by χ2 test to identify significant associations between genotypes and the presence of aneurysms. RESULTS: Two hundred sixty-nine patients were enrolled into the study. There was a significant correlation with the presence of aneurysms for the GC allele of the SNP rs42524 in exon 28 (P = .02). The other polymorphisms did not show significant correlations. CONCLUSIONS: The COL1A2 gene is associated with intracranial aneurysms in a subset of the German population. However, it is not responsible for the majority of aneurysms, and further candidate genes need to be identified to develop sensitive genetic screening for patients at risk.

The stuff of memories: Planning hindsight in animal cryobanks.

Biobanks are becoming ubiquitous infrastructures in zoology and other non-human life sciences. They promise to store frozen research samples for the long term for future use. That use remains speculative but nevertheless needs to be anticipated. Following the establishment of a physical and digital infrastructure for frozen samples in an animal biobanking project, this article explores how the future is anticipated to remember the past, and how frozen objects are shaped accordingly. Situating the biobank between mundane freezing routines in a research lab and the 'dry' and 'wet' collections of natural history museums, I argue that frozen research objects need to be conserved in two separate ways. The unavailability of cryo-objects in cold storage forces researchers to store materials independently of metadata, while retaining a link between them that allows for their reunion after thawing. The result is a split object, leading a double life at sub-zero and room temperature, linked only through the surface of special plastic containers. Following the making of such split objects, this article offers an elaboration of Radin's 'planned hindsight' as well as a reflection on the universality and particularity of biobanks as standardized scientific memory.

Extracranial metastasizing solitary fibrous tumors (SFT) of meninges: histopathological features of a case with long-term follow-up.

Extrapleural solitary fibrous tumors are uncommon mesenchymal neoplasms frequently observed in middle-aged adults and are classified, according to the WHO classification of soft tissue tumors, as part of the hemangiopericytoma tumor group. However, these two entities remain separated in the WHO classification of tumors of the central nervous system. In fact, meningeal solitary fibrous tumors are believed to be benign lesion and only in a minority of cases local relapses have been described, although detailed survival clinical studies on solitary fibrous tumors of meninges are rare. In contrast to hemangiopericytoma, which frequently shows distant extracranial metastases, such an event is exceptional in patients with meningeal solitary fibrous tumors and has been clinically reported in a handful of cases only and their histopathological features have not been investigated in detail. In this report, we describe the detailed clinico-pathological features of a meningeal solitary fibrous tumor presenting during a 17-year follow-up period, multiple intra-, extracranial relapses and lung metastases.

Anatomically Integrated In-Place Visualization of Patient Data for Cooperative Tasks with a Case Study on a Neurosurgical Ward.

The workflow in modern hospitals entails that the medical treatment of a patient is distributed between several physicians and nurses. This leads to intensive cooperation, which takes place under particular time pressure and requires efficient conveyance of relevant patient-related medical data to colleagues. This requirement is difficult to achieve with traditional data representation approaches. In this paper, we introduce a novel concept of anatomically integrated in-place visualization designed to engage with cooperative tasks on a neurosurgical ward by using a virtual patient's body as spatial representation of visually encoded abstract medical data. Based on the findings of our field studies, we provide a set of formal requirements and procedures for this kind of visual encoding. Moreover, we implemented a prototype on a mobile device that supports the diagnosis of spinal disc herniation and has been evaluated by 10 neurosurgeons. The physicians have assessed the proposed concept as beneficial, especially emphasizing the advantages of the anatomical integration such as intuitiveness and a better data availability due to providing all information at a glance. Particularly, four of nine respondents have stressed solely benefits of the concept, other four have mentioned benefits with some limitations and only one person has seen no benefits.

Rationale and design of the peripheral nerve tumor registry: an observational cohort study.

AIM: Peripheral nerve tumors (PNT) are rare lesions. To date, no systematic multicenter studies on epidemiology, clinical symptoms, treatment strategies and outcomes, genetic and histopathologic features, as well as imaging characteristics of PNT were published. The main goal of our PNT Registry is the systematic multicenter investigation to improve our understanding of PNT and to assist future interventional studies in establishing hypotheses, determining potential endpoints, and assessing treatment efficacy. METHODS: Aims of the PNT registry were set at the 2015 Meeting of the Section of Peripheral Nerve Surgery of the German Society of Neurosurgery. A study protocol was developed by specialists in PNT care. A minimal data set on clinical status, treatment types and outcomes is reported by each participating center at initial contact with the patient and after 1 year, 2 years, and 5 years. Since the study is coordinated by the Charité Berlin, the PNR Registry was approved by the Charité ethics committee (EA4/058/17) and registered with the German Trials Registry (www.drks.de). On a national level, patient inclusion began in June 2016. The registry was rolled out across Europe at the 2019 meeting of the European Association of Neurosurgery in Dublin. RESULTS: Patient recruitment has been initiated at 10 centers throughout Europe and 14 additional centers are currently applying for local ethics approval. CONCLUSION: To date, the PNT registry has grown into an international study group with regular scientific and clinical exchange awaiting the first results of the retrospective study arm.

Hybrid Capability to Integrate Multiple Treatment Modalities for Managing High-Grade Intracranial Dural Arteriovenous Fistulas.

BACKGROUND: An integrated multimodality approach can be effective in treatment of high-grade dural arteriovenous fistulas. Nevertheless, this requires a high level of efficient cooperation between different departments, underlying a degree of bias in the decisional process. In comparison, hybrid capability, integrating these modalities in one hand, may allow aggregating multimodality treatment strategies by pooling their individual benefits, leading to a more holistic view of the consequences of each modality. METHODS: We retrospectively reviewed 18 cases of dural arteriovenous fistulas subjected to a hybrid treatment approach at the Diakonieklinikum Jung-Stilling, Siegen, Germany, between March 2008 and January 2017. Nine cases were excluded. We selected 4 cases that highlight different aspects of hybrid capability for illustrative purposes. RESULTS: Hybrid capability allows treatment of a dural arteriovenous fistula based on the individual clinical situation of the patient and features of the lesion, free of interdepartmental bias. The surgeon maintains a level of flexibility that enables him or her to move from a minimally invasive endovascular approach to a maximally invasive surgical access according to the specific situation. Hybrid capability can lead to a highly efficient treatment regimen with palliation of symptoms and complete obliteration of the fistula, improving performance in these complex pathologies. CONCLUSIONS: Hybrid capability has great potential in the treatment of complex neurovascular lesions. It remains to be seen if a single surgeon with hybrid capability can supersede the current multidepartmental practice and achieve better outcomes.

Accuracy of pedicle screw insertion in the cervical spine for internal fixation using frameless stereotactic guidance.

OBJECT: Although transpedicular fixation is a biomechanically superior technique, it is not routinely used in the cervical spine. The risk of neurovascular injury in this region is considered high because the diameter of cervical pedicles is very small and their angle of insertion into the vertebral body varies. This study was conducted to analyze the clinical accuracy of stereotactically guided transpedicular screw insertion into the cervical spine. METHODS: Twenty-seven patients underwent posterior stabilization of the cervical spine for degenerative instability resulting from myelopathy, fracture/dislocation, tumor, rheumatoid arthritis, and pyogenic spondylitis. Fixation included 1-6 motion segments (mean 2.2 segments). Transpedicular screws (3.5-mm diameter) were placed using 1 of 2 computer-assisted guidance systems and lateral fluoroscopic control. The intraoperative mean deviation of frameless stereotaxy was < 1.9 mm for all procedures. RESULTS: No neurovascular complications resulted from screw insertion. Postoperative computed tomography (CT) scans revealed satisfactory positioning in 104 (90%) of 116 cervical pedicles and in all 12 thoracic pedicles. A noncritical lateral or inferior cortical breach was seen with 7 screws (6%). Critical malplacement (4%) was always lateral: 5 screws encroached into the vertebral artery foramen by 40-60% of its diameter; Doppler sonographic controls revealed no vascular compromise. Screw malplacement was mostly due to a small pedicle diameter that required a steep trajectory angle, which could not be achieved because of anatomical limitation in the exposure of the surgical field. CONCLUSIONS: Despite the use of frameless stereotaxy, there remains some risk of critical transpedicular screw malpositioning in the subaxial cervical spine. Results may be improved by the use of intraoperative CT scanning and navigated percutaneous screw insertion, which allow optimization of the transpedicular trajectory.

[Functional MR imaging of working memory before neurosurgery]. / Funktionelle MR-Bildgebung des Arbeitsgedächtnisses vor neurochirurgischen Eingriffen.

Information concerning the tissue adjacent to a brain tumour is crucial for planning and performing a neurosurgical intervention. In this study, we evaluated the usefulness of functional imaging of working memory in terms of working memory preservation. Working memory performance of 14 patients with prefrontal tumours was tested preoperatively by means of a standardized neuropsychological test battery. Also, functional magnetic resonance imaging (fMRI) using a so-called two-back paradigm was performed to visualize brain areas related to that task. Working memory areas were reliably detected in all patients. Surgery was then planned on the basis of this information, and the data were used for intra-operative cranial neuronavigation. Three to twelve months after surgery, patients were tested again with the test battery in order to detect possible changes in working memory performance. In 13 cases the memory performance was unchanged, only one female patient had a slight impairment of working memory compared to the pre-operative status.

Selective peripheral denervation for spasmodic torticollis: 13-year experience with 155 patients.

OBJECT: Botulinum toxin injections are the best therapeutic option in patients with spasmodic torticollis. Although a small number of patients do not benefit from such therapy, the majority respond well but may develop antibodies to the toxin after repeated applications. In those termed primary nonresponders, no improvement related to botulinum toxin has been shown. In patients in whom no response was shown and those in whom resistance to the therapy developed, selective peripheral denervation is a neurosurgical option. METHODS: Between June 1988 and August 2001, 155 patients underwent selective peripheral denervation. Surgery was performed at a mean of 8.5 years after the onset of symptoms (range 0.5-37 years). The mean age of the patients at the onset of dystonia was 39.7 years (range 17-77 years). For evaluation of results, patients' responses were assessed. Results were obtained in 140 patients in whom the follow-up period ranged from 3 to 124 months (mean 32.8 months): 18 reported complete relief of their symptoms, 50 significant relief, and 34 moderate relief; 19 noted only minor relief and the remaining 19 no improvement. The results differ substantially when compared with those previously demonstrated in patients who received botulinum toxin injections. Although 80% of the secondary nonresponders were satisfied with the result of surgery, only 62% of the primary nonresponders considered the operation helpful. There were no major side effects. The recurrence rate was 11%. CONCLUSIONS: The injection of botulinum toxin should be the first-choice treatment. If surgery is required, selective peripheral denervation provides the best results and has the fewest side effects compared with all surgical options.

Four distinct structural domains in Clostridium difficile toxin B visualized using SAXS.

Clostridium difficile is a nosocomial bacterial pathogen causing antibiotic-associated diarrhea and fatal pseudomembranous colitis. Key virulence factors are toxin A and toxin B (TcdB), two highly related toxins that are members of the large clostridial toxin family. These large multifunctional proteins disrupt cell function using a glucosyltransferase domain that is translocated into the cytosol after vesicular internalization of intact holotoxin. Although substantial information about the biochemical mechanisms of intoxication exists, research has been hampered by limited structural information, particularly of intact holotoxin. Here, we used small-angle X-ray scattering (SAXS) methods to obtain an ab initio low-resolution structure of native TcdB, which demonstrated that this molecule is monomeric in solution and possesses a highly asymmetric shape with a maximum dimension of approximately 275 A. Combining this SAXS information with crystallographic or modeled structures of individual functional domains of TcdB reveals for the first time that the three-dimensional structure of TcdB is organized into four distinct structural domains. Structures of the N-terminal glucosyltransferase, the cysteine protease, and the C-terminal repeat region can be aligned within three domains of the SAXS envelope. A fourth domain, predicted to be involved in the translocation of the glucosyltransferase, appears as a large solvent-exposed protrusion. Knowledge of the shapes and relative orientations of toxin domains provides new insight into defining functional domain boundaries and provides a framework for understanding how potential intra-domain interactions enable conformational changes to propagate between domains to facilitate intoxication processes.

Small-molecule XIAP inhibitors enhance gamma-irradiation-induced apoptosis in glioblastoma.

Because evasion of apoptosis can cause radioresistance of glioblastoma, there is a need to design rational strategies that counter apoptosis resistance. In the present study, we investigated the potential of targeting the antiapoptotic protein XIAP for the radiosensitization of glioblastoma. Here, we report that small-molecule XIAP inhibitors significantly enhance gamma-irradiation-induced loss of viability and apoptosis and cooperate with gamma-irradiation to suppress clonogenic survival of glioblastoma cells. Analysis of molecular mechanisms reveals that XIAP inhibitors act in concert with gamma-irradiation to cause mitochondrial outer membrane permeabilization, caspase activation, and caspase-dependent apoptosis. Importantly, XIAP inhibitors also sensitize primary cultured glioblastoma cells derived from surgical specimens as well as glioblastoma-initiating stemlike cancer stem cells for gamma-irradiation. In contrast, they do not increase the toxicity of gamma-irradiation on some nonmalignant cells of the central nervous system, including rat neurons or glial cells, pointing to some tumor selectivity. In conclusion, by demonstrating for the first time that small-molecule XIAP inhibitors increase the radiosensitivity of glioblastoma cells while sparing normal cells of the central nervous system, our findings build the rationale for further (pre)clinical development of XIAP inhibitors in combination with gamma-irradiation in glioblastoma.

Phosphatidylinositol 3-kinase inhibition broadly sensitizes glioblastoma cells to death receptor- and drug-induced apoptosis.

The aberrant activity of the phosphatidylinositol 3-kinase (PI3K) pathway has been reported to correlate with adverse clinical outcome in human glioblastoma in vivo. However, the question of how this survival network can be successfully targeted to restore the sensitivity of glioblastoma to apoptosis induction has not yet been answered. Here, we report that inhibition of PI3K by LY294002 broadly sensitizes wild-type and mutant PTEN glioblastoma cells to both death receptor- and chemotherapy-induced apoptosis, whereas mammalian target of rapamycin (mTOR) inhibition is not sufficient to restore apoptosis sensitivity. LY294002 significantly enhances apoptosis triggered by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), agonistic anti-CD95 antibodies, or several anticancer drugs (i.e., doxorubicin, etoposide, and vincristine) in a highly synergistic manner. In addition, LY294002 cooperates with TRAIL or doxorubicin to suppress colony formation, thus also showing a strong effect on long-term survival. Similarly, genetic knockdown of PI3K subunits p110alpha and/or p110beta by RNA interference (RNAi) primes glioblastoma cells for TRAIL- or doxorubicin-mediated apoptosis. In contrast to PI3K inhibition, pharmacologic or genetic blockade of mTOR by RAD001 (everolimus), rapamycin, or RNAi fails to enhance TRAIL- or doxorubicin-induced apoptosis. Analysis of apoptosis pathways reveals that PI3K inhibition acts in concert with TRAIL or doxorubicin to trigger mitochondrial membrane permeabilization, caspase activation, and caspase-dependent apoptosis, which are abolished by the caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone. Most importantly, PI3K inhibition by LY294002 sensitizes primary cultured glioblastoma cells obtained from surgical specimens to TRAIL- or chemotherapy-induced cell death. By showing that PI3K inhibition broadly primes glioblastoma cells for apoptosis, our findings provide the rationale for using PI3K inhibitors in combination regimens to enhance TRAIL- or chemotherapy-induced apoptosis in glioblastoma.

Treatment and outcome of aneurysmal subarachnoid haemorrhage in the elderly patient.

From January 1999 to May 2003, 316 aneurysms were treated, among them 40 patients (12.7%) over 65 years with subarachnoid haemorrhage (SAH). The results of this sub-group are presented. Mean age was 71 years (range 65-83 years), 40% of the patients were in (Hunt & Hess) grade I-III and 60% grade IV-V. Eighty-five percent of the aneurysms were located in the anterior circulation (35% ACom aneurysms). Nineteen aneurysms were coiled (all basilar tip and small-based ACom aneurysms), two among them subsequently clipped after coil compaction, 18 were initially clipped (most of MCA and all broad-based ACom aneurysms), two wrapped and one trapped. A total of 66.7% of the patients with coiled and 60.0% with clipped aneurysms had been hospitalized in poor condition (Hunt & Hess IV-V). The average follow-up period was 16 months. Overall, 35% of patients fully recovered, 5% returned to normal activity with some deficit, 33% remained dependent and 27% died. All seven patients with MCA aneurysms and intracerebral haematoma were clipped, but died or remained vegetative. Ten of 17 coiled patients (58.8%) had a favourable outcome, compared to 4/11 (36.4%) in the clip group, but two primarily coiled aneurysms rebled due to coil compaction. The outcome is dependent on the primary Hunt & Hess grade. A total of 48.5% of SAH patients without intracerebral bleeding fully recovered, even patients in poor primary grade. Additional intracerebral haemorrhage is linked to a bad outcome. As primary procedure, the less traumatic coiling seems to be superior to clipping primarily. Better Hunt & Hess grades have a statistically significant chance for a promising outcome.

Clostridium difficile IStron CdISt1: discovery of a variant encoding two complete transposase-like proteins.

Screening a Clostridium difficile strain collection for the chimeric element CdISt1, we identified two additional variants, designated CdISt1-0 and CdISt1-III. In in vitro assays, we could prove the self-splicing ribozyme activity of these variants. Structural comparison of all known CdISt1 variants led us to define four types of IStrons that we designated CdISt1-0 through CdISt1-III. Since CdISt1-0 encodes two complete transposase-like proteins (TlpA and TlpB), we suggest that it represents the original genetic element, hypothesized before to have originated by fusion of a group I intron and an insertion sequence element.

The IStron CdISt1 of Clostridium difficile: molecular symbiosis of a group I intron and an insertion element.

The IStron CdISt1 was first discovered as an insertion into the tcdA gene of the clinical isolate C34. It combines structural and functional properties of a group I intron at its 5'-end with those of an insertion element at its 3'-end. Up to date four different types could be found, mainly differing in their IS-element portions. Contrasting classical group I introns, CdISt1 is always integrated in ORFs encoding bacterial protein. In case CdISt1 had only the IS-element function such insertion would inactivate the protein encoded by the host gene. It is only due to the self-splicing activity of the group I intron parts that CdISt1 integration does not abolish protein function. Both elements seem to exist in molecular symbiosis and CdISt1 could thus be a prototype of a novel class of genetic elements. Moreover, integration of the CdISt1 into the genome could be advantageous for the bacterium, a motor function for evolution of bacterial proteins is discussed. In clinical practice CdISt1 might well serve as a tool for epidemiological studies of C. difficile infections.

Mutation and expression analysis of the KRIT1 gene associated with cerebral cavernous malformations (CCM1).

Cavernous malformations are vascular anomalies that can cause severe neurological deficits, seizures and hemorrhagic stroke if these lesions are located in the brain. In patients with cavernomas, constitutional mutations of the KRIT1 gene have been identified. The pathogenetic mechanisms leading to cerebral cavernous malformations (CCM) development are poorly understood. CCM development might be induced in utero owing to the underlying KRIT1 defect, and is triggered by environmental factors. Another model suggests that CCM develop according to the two-hit model of tumorigenesis associated with biallelic inactivation of KRIT1. So far, CCM specimens themselves have not been subjected to mutation analysis. We identified two somatic mutations in the cavernoma of a sporadic case, suggesting that pathogenesis is associated with somatic KRIT1 alterations. To gain a better understanding of the role of KRIT1 during morphogenesis, the main goal of this study was to provide a detailed description of the spatio-temporal expression pattern of Krit1 and its interaction partner Rap1A during mouse embryogenesis. We did not observe enhanced expression of either gene in the heart or large vessels; however, their expression in the developing small vessels or capillaries could not be assessed by the methods applied. At early embryonic stages, Krit1 and, to a lesser extent, Rap1A are expressed in the developing nervous system. During later phases of fetal development, specific expression of both genes is observed in regions of ossification, the dermis, tendons and in the meninges. These findings provide evidence of differential Krit1 and Rap1A expression during mouse ontogenesis and suggest a more widespread functional significance of Krit1, not restricted to vascular endothelial cells.