Quality Assessment of Surgical Disc Samples Discriminates Human Annulus Fibrosus and Nucleus Pulposus on Tissue and Molecular Level.

A discrimination of the highly specialised annulus fibrosus (AF) and nucleus pulposus (NP) cells in the mature human intervertebral disc (IVD) is thus far still not possible in a reliable way. The aim of this study was to identify molecular markers that distinguish AF and NP cells in human disc tissue using microarray analysis as a screening tool. AF and NP samples were obtained from 28 cervical discs. First, all samples underwent quality sorting using two novel scoring systems for small-sized disc tissue samples including macroscopic, haptic and histological evaluation. Subsequently, samples with clear disc characteristics of either AF or NP that were free from impurities of foreign tissue (IVD score) and with low signs of disc degeneration on cellular level (DD score) were selected for GeneChip analysis (HGU1332P). The 11 AF and 9 NP samples showed distinctly different genome-wide transcriptomes. The majority of differentially expressed genes (DEGs) could be specifically assigned to the AF, whereas no DEG was exclusively expressed in the NP. Nevertheless, we identified 11 novel marker genes that clearly distinguished AF and NP, as confirmed by quantitative gene expression analysis. The novel established scoring systems and molecular markers showed the identity of AF and NP in disc starting material and are thus of great importance in the quality assurance of cell-based therapeutics in regenerative treatment of disc degeneration.

Decompressive Hemicraniectomy in Malignant Middle Cerebral Artery Infarction: The 'Real World' Beyond Studies.

BACKGROUND: Decompressive hemicraniectomy (DHC) is life-saving in patients with malignant middle cerebral artery infarction (MMI), but outcome, perspectives and complications after DHC in daily practice are largely unknown. METHODS: From 2008 until 2014, we extracted patient's characteristics as well as complications from our database for patients with MMI who underwent DHC. Additionally, we analysed medical records from the different rehabilitation steps. RESULTS: We identified 48 consecutive patients (mean 57 years, 21 male, 41.7% >60 years) with MMI who underwent DHC. The decision for DHC was made on an individual basis, including patients without impaired consciousness or stroke onset >48 h. In-hospital patients achieved only marginal clinical improvement. Seventy-five percent attended an early-rehabilitation, 44% achieved post-stroke rehabilitation and 6% carried on late-stage rehabilitation. In all, 45.5% returned home after rehabilitation. In-hospital mortality was 14.6%, overall mortality was 16.7%. Surviving patients (78.9%) had a modified Rankin Scale of 4-5. Frequent neurologic complications were symptomatic epilepsy and delirium. Following DHC/bone-flap-reimplantation, wound-healing disorders, epidural hematoma and wound infections were major surgery-related complications. Pulmonary infections were frequent in the acute-phase and urinary tract infections were predominant in the late-phase. CONCLUSIONS: DHC is a life-saving technique in patients with MMI, but complications are frequent, were underestimated in randomized clinical trials and may worsen the functional outcome.

Methylation-based classification of benign and malignant peripheral nerve sheath tumors.

The vast majority of peripheral nerve sheath tumors derive from the Schwann cell lineage and comprise diverse histological entities ranging from benign schwannomas and neurofibromas to high-grade malignant peripheral nerve sheath tumors (MPNST), each with several variants. There is increasing evidence for methylation profiling being able to delineate biologically relevant tumor groups even within the same cellular lineage. Therefore, we used DNA methylation arrays for methylome- and chromosomal profile-based characterization of 171 peripheral nerve sheath tumors. We analyzed 28 conventional high-grade MPNST, three malignant Triton tumors, six low-grade MPNST, four epithelioid MPNST, 33 neurofibromas (15 dermal, 8 intraneural, 10 plexiform), six atypical neurofibromas, 43 schwannomas (including 5 NF2 and 5 schwannomatosis associated cases), 11 cellular schwannomas, 10 melanotic schwannomas, 7 neurofibroma/schwannoma hybrid tumors, 10 nerve sheath myxomas and 10 ganglioneuromas. Schwannomas formed different epigenomic subgroups including a vestibular schwannoma subgroup. Cellular schwannomas were not distinct from conventional schwannomas. Nerve sheath myxomas and neurofibroma/schwannoma hybrid tumors were most similar to schwannomas. Dermal, intraneural and plexiform neurofibromas as well as ganglioneuromas all showed distinct methylation profiles. Atypical neurofibromas and low-grade MPNST were indistinguishable with a common methylation profile and frequent losses of CDKN2A. Epigenomic analysis finds two groups of conventional high-grade MPNST sharing a frequent loss of neurofibromin. The larger of the two groups shows an additional loss of trimethylation of histone H3 at lysine 27 (H3K27me3). The smaller one retains H3K27me3 and is found in spinal locations. Sporadic MPNST with retained neurofibromin expression did not form an epigenetic group and most cases could be reclassified as cellular schwannomas or soft tissue sarcomas. Widespread immunohistochemical loss of H3K27me3 was exclusively seen in MPNST of the main methylation cluster, which defines it as an additional useful marker for the differentiation of cellular schwannoma and MPNST.