Dynamic cervical flexion/extension atlantodental interval and functional outcome of the Harms technique for posterior C1/2 fixation: A retrospective analysis of 16 atlantoaxial subluxation cases in a tertiary medical center.

BACKGROUND: The aim of this study was to assess the relationship between the atlantodental interval (ADI) on dynamic flexion/extension cervical radiographs and functional outcomes of posterior spinal fixation by the Harms technique for atlantoaxial subluxation (AAS). Dynamic flexion/extension on cervical radiographs is a standard assessment for evaluation of C1/2 instability in AAS patients. Most studies focused on postoperative ADI and functional outcome, including pain and fusion rate; only few studies compared dynamic ADI change pre- to post-operatively. MATERIAL AND METHODS: Retrospectively, we reviewed the medical records of 16 patients who underwent posterior spinal fixation in our center from 2018 to 2019. We used dynamic cervical flexion/extension radiographs to assess the pre- to postoperative change at 12 months in ADI of flexion (ADIf), ADI of extension (ADIe), ADI between flexion/extension (ADIΔ), C1/2 fusion rate and functional outcomes measured by the modified Japanese Orthopaedic Association scale (mJOA scale). Postoperative CT at 3∼12 months assessed screw positioning on the Gertzbein and Robbins classification. RESULTS: In the 16 patients included in this study, ADIf, ADIe and ADIΔ were significantly reduced, from respectively 8.0mm, 5.0mm and 3.0mm preoperatively to 4.6mm, 3.8mm and 0.8mm at 12 months' follow-up. The fusion rate was 81% and the mJOA score recovery rate was 34.9±14.7%. Although the screw malposition rate was higher than in other studies in C1(10%) and C2(20%), there were no new neurologic deficits or worsening of symptoms at follow-up. CONCLUSIONS: The ADIΔ showed significant reduction, showing that the Harms technique of posterior spinal fixation can effective in maintaining the stability of the atlantoaxial joint and improving functional outcome.

Progranulin promotes Temozolomide resistance of glioblastoma by orchestrating DNA repair and tumor stemness.

Glioblastoma multiforme (GBM) is the most common malignant brain tumor in adults with a dismal prognosis. Current therapy of surgical removal combined with Temozolomide (TMZ) and radiation therapy only slightly prolongs the survival of GBM patients. Thus, it is essential to elucidate mechanism underlying its highly malignant properties in order to develop efficacious therapeutic regimens. In this study, we showed that progranulin (PGRN) was overexpressed in most GBM cell lines and the majority of human tumor samples. PGRN overexpression conferred GBM cells with tumorigenic properties and TMZ resistance by upregulating DNA repair (PARP, ATM, BRCA1, Rad51, XRCC1 and so on) and cancer stemness (CD133, CD44, ABCG2) genes, in part via an AP-1 transcription factor, specifically cFos/JunB. Curcumin, an AP-1 inhibitor, was also found to regulate PGRN promoter activity and expression including its downstream effectors aforementioned. These data suggested a feedforward loop between PGRN signaling and AP-1. PGRN depletion significantly decreased unlimited self-renewal and multilineage differentiation and the malignant properties of GBMs cells S1R1, and enhanced their vulnerability to TMZ. In addition, S1R1 depleted of PGRN also lost the ability to form tumor in an orthotopic xenograft mouse model. In conclusion, PGRN had a critical role in the pathogenesis and chemoresistance of GBM and functioned at the top of the hierarchy of cellular machinery that modulates both DNA repair pathways and cancer stemness. Our data suggest that a new strategy combining current regimens with compounds targeting PGRN/AP-1 loop like curcumin may significantly improve the therapeutic outcome of GBM.

Predisposing factors of pituitary hemorrhage.

BACKGROUND AND PURPOSE: The clinical features of pituitary adenomas were retrospectively analyzed, focusing on the factors that contribute to the development of pituitary hemorrhage. Although many causes of pituitary adenoma hemorrhage have been identified, it is difficult to distinguish which conditions are truly causative. We determined the independent variables that contribute to pituitary hemorrhage in pituitary adenoma. METHODS: Two hundred and eighty-eight consecutive patients diagnosed as pituitary adenoma were enrolled. These patients underwent tumor removal through endoscopic transsphenoidal approach. The subjects were divided into hemorrhagic and non-hemorrhagic groups, based on magnetic resonance images and histological findings. The predisposing factors were reviewed in the medical records for all patients. Univariate and multivariate analyses were performed to assess the relationships between variables of pituitary adenoma hemorrhage. RESULTS: We investigated 81 patients in whom hemorrhage from pituitary adenoma occurred. The incidence of pituitary hemorrhage was 28.1% (81/288). The predisposing factors surveyed for pituitary hemorrhage were significantly associated with macroadenoma, non-functional adenomas, anticoagulation therapy, end-stage renal disease, dopamine agonist treatment, and underlying malignant disease (all P < 0.05). Sex, age, hypertension, diabetes mellitus, and previous radiation therapy were not related to pituitary hemorrhage. CONCLUSIONS: In this pooled cohort, the predisposing factors of pituitary adenoma characteristic for pituitary hemorrhage were macroadenoma and non-functional adenoma. Patients who received dopamine agonist and anticoagulation therapy are implicated as precipitating factors. Underlying end-stage renal disease and malignant disease are also factors that contribute to pituitary adenoma hemorrhage.

Minimally invasive vertebroplasty in the treatment of pain induced by spinal metastatic tumor.

Spinal metastatic tumor is a common problem and represents a challenging problem in oncology practice. Patients with osteolytic metastases often suffer from intractable local and/or radicular pain. Percutaneous vertebroplasty is a minimally invasive, radiologically guided procedure whereby bone cement is injected into structurally weakened vertebrae to provide immediate biomechanical stability. Vertebroplasty is also used to relieve pain by stabilizing metastatically compromised vertebrae that are at risk of pathological burst fracture. In this retrospective study, a total of 57 patients (78 vertebrae) with spinal metastatic tumor were treated with PMMA vertebroplasty. The mean value of the visual analogue scale (VAS) was 8.1 +/- 0.67 preoperatively, and significantly decreased to 3.8 +/- 1.9 (1-8, p < 0.015) one day after vertebroplasty. The mean VAS value 6 months after vertebroplsty was 2.8 +/- 2.0 (p < 0.001). Mean injected bone cement amount in our study is 5.16 +/- 1.6 mL. The complication rate is about 21.8%, bone cement extravasation without neurological deficit is the most common complication. No new or adjacent vertebral fracture has occurred in more than 2 years follow-up. Percutaneous vertebroplasty is a minimally invasive procedure that offers a remarkable advantage of effective and immediate pain relief with few complications.

HDDD2 is a familial frontotemporal lobar degeneration with ubiquitin-positive, tau-negative inclusions caused by a missense mutation in the signal peptide of progranulin.

OBJECTIVE: Familial autosomal dominant frontotemporal dementia with ubiquitin-positive, tau-negative inclusions in the brain linked to 17q21-22 recently has been reported to carry null mutations in the progranulin gene (PGRN). Hereditary dysphasic disinhibition dementia (HDDD) is a frontotemporal dementia with prominent changes in behavior and language deficits. A previous study found significant linkage to chromosome 17 in a HDDD family (HDDD2), but no mutation in the MAPT gene. Longitudinal follow-up has enabled us to identify new cases and to further characterize the dementia in this family. The goals of this study were to develop research criteria to classify the different clinical expressions of dementia observed in this large kindred, to identify the causal mutation in affected individuals and correlate this with phenotypic characteristics in this pedigree, and to assess the neuropathological characteristics using immunohistochemical techniques. METHODS: In this study we describe a detailed clinical, pathological and mutation analysis of the HDDD2 kindred. RESULTS: Neuropathologically, HDDD2 represents a familial frontotemporal lobar degeneration with ubiquitin-positive, tau-negative inclusions (FTLD-U). We developed research classification criteria and identified three distinct diagnostic thresholds, which helped localize the disease locus. The chromosomal region with the strongest evidence of linkage lies within the minimum critical region for FTLD-U. Sequencing of each exon of the PGRN gene led to the identification of a novel missense mutation, Ala-9 Asp, within the signal peptide. INTERPRETATION: HDDD2 is an FTLD-U caused by a missense mutation in the PGRN gene that cosegregates with the disease and with the disease haplotype in at-risk individuals. This mutation is the first reported pathogenic missense mutation in the signal peptide of the PGRN gene causing FTLD-U. In light of the previous reports of null mutations and its position in the gene, two possible pathological mechanisms are proposed: (1) the protein may accumulate within the endoplasmic reticulum due to inefficient secretion; and (2) mutant RNA may have a lower expression because of degradation via nonsense-mediated decay.

A novel method of automated skull registration for forensic facial approximation.

Modern forensic facial reconstruction techniques are based on an understanding of skeletal variation and tissue depths. These techniques rely upon a skilled practitioner interpreting limited data. To (i) increase the amount of data available and (ii) lessen the subjective interpretation, we use medical imaging and statistical techniques. We introduce a software tool, reality enhancement/facial approximation by computational estimation (RE/FACE) for computer-based forensic facial reconstruction. The tool applies innovative computer-based techniques to a database of human head computed tomography (CT) scans in order to derive a statistical approximation of the soft tissue structure of a questioned skull. A core component of this tool is an algorithm for removing the variation in facial structure due to skeletal variation. This method uses models derived from the CT scans and does not require manual measurement or placement of landmarks. It does not require tissue-depth tables, can be tailored to specific racial categories by adding CT scans, and removes much of the subjectivity of manual reconstructions.

Esophageal perforation complicating with spinal epidural abscess, iatrogenic or secondary to first thoracic spine fracture?

A 49-year-old drunken man was involved in a motorbike crash. He presented with cervical spine injury and multiple limbs fracture. Neuro-imaging demonstrated disruption of the C5-6 anterior longitudinal ligament, herniation of C3-4 and C5-6 discs, and Th1 compression fracture. The neurological deficits improved after anterior cervical decompression, fusion and fixation. One week later, he suffered from fever and severe upper back pain, and he developed paraplegia subsequently. The following image study disclosed esophageal perforation at the level of Th1 and epidural abscess spreading from levels Th1 to Th5. After proper management and rehabilitation, he achieved good recovery one year later at follow-up. We report the unique case of Th1 fracture with esophageal perforation complicated with spinal epidural abscess. The possible mechanism and the controversy concerning therapy for esophageal perforation are discussed.

Formation of compact myelin is required for maturation of the axonal cytoskeleton.

Although traditional roles ascribed to myelinating glial cells are structural and supportive, the importance of compact myelin for proper functioning of the nervous system can be inferred from mutations in myelin proteins and neuropathologies associated with loss of myelin. Myelinating Schwann cells are known to affect local properties of peripheral axons (de Waegh et al., 1992), but little is known about effects of oligodendrocytes on CNS axons. The shiverer mutant mouse has a deletion in the myelin basic protein gene that eliminates compact myelin in the CNS. In shiverer mice, both local axonal features like phosphorylation of cytoskeletal proteins and neuronal perikaryon functions like cytoskeletal gene expression are altered. This leads to changes in the organization and composition of the axonal cytoskeleton in shiverer unmyelinated axons relative to age-matched wild-type myelinated fibers, although connectivity and patterns of neuronal activity are comparable. Remarkably, transgenic shiverer mice with thin myelin sheaths display an intermediate phenotype indicating that CNS neurons are sensitive to myelin sheath thickness. These results indicate that formation of a normal compact myelin sheath is required for normal maturation of the neuronal cytoskeleton in large CNS neurons.

Mice with disrupted midsized and heavy neurofilament genes lack axonal neurofilaments but have unaltered numbers of axonal microtubules.

Mammalian neurofilaments are assembled from the light (NF-L), midsized (NF-M), and heavy (NF-H) neurofilament proteins. While NF-M and NF-H cannot self-assemble into homopolymers, the data concerning NF-L has been more contradictory. In vitro bovine, porcine, and murine NF-L can homopolymerize in the absence of other subunits. However, in vivo studies suggest that neither rat nor mouse NF-L can form filaments when transfected alone into cells lacking endogenous intermediate filaments. By contrast, human NF-L forms homopolymers in similar cell lines. Recently we generated mice with null mutations in the NF-M and NF-H genes. To determine if mouse NF-L can homopolymerize in mouse axons, NF-M and NF-H null mutants were bred to create a line of double mutant animals. Here we show that axons in NF-M/H double mutant animals are largely devoid of 10-nm filaments. Instead, the axoplasm is transformed to a microtubule-based cytoskeleton-although the lack of any increase in tubulin levels per unit length of nerve or of increases in microtubule numbers relative to myelin sheath thickness argues that microtubules are not increased in response to the loss of neurofilaments. Thus in vivo rodent neurofilaments are obligate heteropolymers requiring NF-L plus either NF-M or NF-H to form a filamentous network.

Requirement of heavy neurofilament subunit in the development of axons with large calibers.

Neurofilaments (NFs) are prominent components of large myelinated axons. Previous studies have suggested that NF number as well as the phosphorylation state of the COOH-terminal tail of the heavy neurofilament (NF-H) subunit are major determinants of axonal caliber. We created NF-H knockout mice to assess the contribution of NF-H to the development of axon size as well as its effect on the amounts of low and mid-sized NF subunits (NF-L and NF-M respectively). Surprisingly, we found that NF-L levels were reduced only slightly whereas NF-M and tubulin proteins were unchanged in NF-H-null mice. However, the calibers of both large and small diameter myelinated axons were diminished in NF-H-null mice despite the fact that these mice showed only a slight decrease in NF density and that filaments in the mutant were most frequently spaced at the same interfilament distance found in control. Significantly, large diameter axons failed to develop in both the central and peripheral nervous systems. These results demonstrate directly that unlike losing the NF-L or NF-M subunits, loss of NF-H has only a slight effect on NF number in axons. Yet NF-H plays a major role in the development of large diameter axons.

Glial cytoplasmic inclusions in white matter oligodendrocytes of multiple system atrophy brains contain insoluble alpha-synuclein.

Recently, alpha-synuclein was shown to be a structural component of the filaments in Lewy bodies (LBs) of Parkinson's disease (PD), dementia with LBs (DLB) as well as the LB variant of Alzheimer's disease, and this suggests that alpha-synuclein could play a mechanistic role in the pathogenesis of these disorders. To determine whether alpha-synuclein is a building block of inclusions in other neurodegenerative movement disorders, we examined brains from patients with multiple system atrophy (MSA) and detected alpha-synuclein, but not beta- or gamma-synuclein, in glial cytoplasmic inclusions (GCIs) throughout the MSA brain. In MSA white matter, alpha-synuclein-positive GCIs were restricted to oligodendrocytes, and alpha-synuclein was localized to the filaments in GCIs by immunoelectron microscopy. Finally, we demonstrated that insoluble alpha-synuclein accumulated selectively in MSA white matter with alpha-synuclein-positive GCIs. Taken together with evidence that LBs contain insoluble alpha-synuclein, our data suggest that a reduction in the solubility of alpha-synuclein may induce this protein to form filaments that aggregate into cytoplasmic inclusions, which contribute to the dysfunction or death of glial cells as well as neurons in neurodegenerative disorders with different phenotypes.

Absence of the mid-sized neurofilament subunit decreases axonal calibers, levels of light neurofilament (NF-L), and neurofilament content.

Neurofilaments (NFs) are prominent components of large myelinated axons and probably the most abundant of neuronal intermediate filament proteins. Here we show that mice with a null mutation in the mid-sized NF (NF-M) subunit have dramatically decreased levels of light NF (NF-L) and increased levels of heavy NF (NF-H). The calibers of both large and small diameter axons in the central and peripheral nervous systems are diminished. Axons of mutant animals contain fewer neurofilaments and increased numbers of microtubules. Yet the mice lack any overt behavioral phenotype or gross structural defects in the nervous system. These studies suggest that the NF-M subunit is a major regulator of the level of NF-L and that its presence is required to achieve maximal axonal diameter in all size classes of myelinated axons.

Myelin-associated glycoprotein is a myelin signal that modulates the caliber of myelinated axons.

Myelination increases neuronal conduction velocity through its insulating properties and an unidentified extrinsic effect that increases axonal caliber. Although it is well established that demyelination can cause axonal atrophy, the myelin molecule that regulates axonal caliber is not known. Loss of the structural proteins of compact peripheral nervous system (PNS) myelin, P0 protein, and myelin basic protein does not lead to axonal atrophy. This study demonstrates that mice with a null mutation of the myelin-associated glycoprotein (MAG) gene have a chronic atrophy of myelinated PNS axons that results in paranodal myelin tomaculi and axonal degeneration. Absence of MAG was correlated with reduced axonal calibers, decreased neurofilament spacing, and reduced neurofilament phosphorylation. Because axonal atrophy and degeneration in MAG-deficient mice occur in the absence of inflammation, hypomyelination, significant demyelination-remyelination, or gain of function mutations, these data support a functional role for MAG in modulating the maturation and viability of myelinated axons.

Aggregation of alpha-synuclein in Lewy bodies of sporadic Parkinson's disease and dementia with Lewy bodies.

Lewy bodies (LBs) are hallmark lesions of degenerating neurons in the brains of patients with Parkinson's disease (PD) and dementia with Lewy bodies (DLB). Recently, a point mutation in the gene encoding the presynaptic alpha-synuclein protein was identified in some autosomal-dominantly inherited familial PD pedigrees, and light microscopic studies demonstrated alpha-synuclein immunoreactivity in LBs of sporadic PD and DLB. To characterize alpha-synuclein in LBs, we raised monoclonal antibodies (MAbs) to LBs purified from DLB brains and obtained a MAb specific for alpha-synuclein that intensely labeled LBs. Light and electron microscopic immunocytochemical studies performed with this MAb as well as other antibodies to alpha-and beta-synuclein showed that alpha-synuclein, but not beta-synuclein, is a component of LBs in sporadic PD and DLB. Western blot analyses of highly purified LBs from DLB brains showed that full-length as well as partially truncated and insoluble aggregates of alpha-synuclein are deposited in LBs. Thus, these data strongly implicate alpha-synuclein in the formation of LBs and the selective degeneration of neurons in sporadic PD and DLB.

Oxidative stress, mutant SOD1, and neurofilament pathology in transgenic mouse models of human motor neuron disease.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that primarily affects motor neurons in the spinal cord and brain stem. About 10% of all ALS cases are familial (FALS), inherited in an autosomal dominant manner. One fifth of FALS patients carry mutations in the Cu/Zn superoxide dismutase (SOD1) gene, and several lines of transgenic mice have been engineered to express mutant forms of the SOD1 gene that are linked to FALS. Significantly, many of these transgenic lines of mice develop a motor neuron disease (MND) that resembles human FALS. Oxidative stress induced by human SOD1 mutations is believed to play an important role in the pathogenesis of FALS and the FALS-like MND seen in the mutant SOD1 transgenic mice. For example, two lines of these mice showed prominent degeneration of mitochondria and endoplasmic reticulum in spinal cord neurons. Furthermore, recent studies have shown that neurofilament (NF)-rich spheroids. Lewy body-like NF inclusions, altered ubiquitin immunoreactivity, and Golgi fragmentation occur in the spinal cord motoneurons of these mutant SOD1 transgenic mice. Because these lesions recapitulate hallmark abnormalities of human ALS, mutant SOD1 transgenic mice provide a useful model for studies designed to elucidate the pathogenesis of ALS. Furthermore, transgenic mice that overexpress NF proteins also develop a clinical and pathologic phenotype similar to human MND, and polymorphisms in an NF gene have been linked to patients with ALS. Collectively, these observations implicate NF protein abnormalities in the pathogenesis of this disorder. Accordingly, this review summarizes recent insights into mechanisms of motor neuron degeneration in ALS that have emerged from studies of these new animal models of this neurodegenerative disease.

Selective degeneration fo Purkinje cells with Lewy body-like inclusions in aged NFHLACZ transgenic mice.

Transgenic (NFHLacZ) mice expressing a fusion protein composed of a truncated high-molecular-weight mouse neurofilament (NF) protein (NFH) fused to beta-galactosidase (LacZ) develop inclusions in neurons throughout the CNS. These inclusions persist from birth to advanced age and contain massive filamentous aggregates including all three endogenous NF proteins and the NFHLacZ fusion protein. Further, the levels of endogenous NF proteins are selectively reduced in NFHLacZ mice. Because these inclusions resemble NF-rich Lewy bodies (LBs) in Parkinson's disease and LB dementia, we asked whether these lesions compromised the viability of affected neurons during aging. We studied hippocampal CA1 neurons, nearly all of which harbored inclusions (type I) devoid of cellular organelles, and cerebellar Purkinje cells, nearly all of which accumulated inclusions (type II) containing numerous entrapped organelles. Purkinje cells with type II inclusions began to degenerate in the NFHLacZ mice at approximately 1 year of age, and most were eliminated by 18 months of age. In contrast, there was no significant loss of type I inclusion-bearing CA1 neurons with age. These data suggest that the sequestration of cellular organelles in type II inclusions may isolate and impair the function of these organelles, thereby rendering Purkinje cells selectively vulnerable to degeneration with age as in neurodegenerative diseases of the elderly characterized by accumulation of LBs.

Transgenic mice carrying a human mutant superoxide dismutase transgene develop neuronal cytoskeletal pathology resembling human amyotrophic lateral sclerosis lesions.

Mutations in the human Cu,Zn superoxide dismutase gene (SOD1) are found in 20% of kindreds with familial amyotrophic lateral sclerosis. Transgenic mice (line G1H) expressing a human SOD1 containing a mutation of Gly-93 --> Ala (G93A) develop a motor neuron disease similar to familial amyotrophic lateral sclerosis, but transgenic mice (line N1029) expressing a wild-type human SOD1 transgene do not. Because neurofilament (NF)-rich inclusions in spinal motor neurons are characteristic of amyotrophic lateral sclerosis, we asked whether mutant G1H and/or N1029 mice develop similar NF lesions. NF inclusions (i.e., spheroids, Lewy body-like inclusions) were first detected in spinal cord motor neurons of the G1H mice at 82 days of age about the time these mice first showed clinical evidence of disease. Other neuronal intermediate filament proteins (alpha-internexin, peripherin) also accumulated in these spheroids. The onset of accumulations of ubiquitin immunoreactivity in the G1H mice paralleled the emergence of vacuoles and NF-rich spheroids in neurons, but they did not colocalize exclusively with spheroids. In contrast, NF inclusions were not seen in the N1029 mice until they were 132 days old, and ubiquitin immunoreactivity was not increased in the N1029 mice even at 199 days of age. Astrocytosis in spinal cord was associated with a marked increase in glial fibrillary acidic protein immunoreactivity in the G1H mice, but not in the N1029 mice. Finally, comparative studies revealed a striking similarity between the cytoskeletal pathology in the G1H transgenic mice and in patients with amyotrophic lateral sclerosis. These findings link a specific SOD1 mutation with alterations in the neuronal cytoskeleton of patients with amyotrophic lateral sclerosis. Thus, neuronal cytoskeletal abnormalities may be implicated in the pathogenesis of human familial amyotrophic lateral sclerosis.

Overexpression of the human NFM subunit in transgenic mice modifies the level of endogenous NFL and the phosphorylation state of NFH subunits.

Neurofilaments (NFs), the major intermediate filaments of central nervous system (CNS) and peripheral nervous system (PNS) neurons, are heteropolymers formed from the high (NFH), middle (NFM), and low (NFL) molecular weight NF subunits. To gain insights into how the expression of NF subunit proteins is regulated in vivo, two transgenes harboring coding sequences for human NFM (hNFM) with or without the hNFM multiphosphorylation repeat domain were introduced into mice. Expression of both hNFM constructs was driven by the hNFM promoter and resulted in increased levels of hNFM subunits concomitant with an elevation in the levels of mouse NFL (mNFL) proteins in the CNS of both lines of transgenic mice. The increased levels of mNFL appear specific to NFM because previous studies of transgenic mice overexpressing either NFL or NFH did not result in increased expression of either of the other two NF subunits. Further, levels of the most heavily phosphorylated isoforms of mouse NFH (mNFH) were reduced in the brains of these transgenic mice, and electron microscopic studies showed a higher packing density of NFs in large-diameter CNS axons of transgenic versus wild-type mice. Thus, reduced phosphorylation of the mNFH carboxy terminal domain may be a compensatory response of CNS neurons to the increase in NFs, and reduced negative charges on mNFH sidearms may allow axons to accommodate more NFs by increasing their packing density. Taken together, these studies imply that NFM may play a dominant role in the in vivo regulation of the levels of NFL protein, the stoichiometry of NF subunits, and the phosphorylation state of NFH. NFM and NFH proteins may assume similar functions in regulation of NF packing density in vivo.