Infection of Glia by Human Pegivirus Suppresses Peroxisomal and Antiviral Signaling Pathways.

Human pegivirus (HPgV) infects peripheral leukocytes but was recently shown to be a neurotropic virus associated with leukoencephalitis in humans. In the present study, we investigated the neural cell tropism of HPgV as well as its effects on host immune responses. HPgV wild type (WT) and a mutant virus with a deletion in the HPgV NS2 gene (ΔNS2) were able to productively infect human astrocytes and microglia but not neurons or an oligodendrocyte-derived cell line. Of note, the ΔNS2 virus replicated better than WT pegivirus in astrocytes, with both viruses being able to subsequently infect and spread in fresh human astrocyte cultures. Infection of human glia by HPgV WT and ΔNS2 viruses resulted in suppression of peroxisome-associated genes, including PEX11B, ABCD1, PEX7, ABCD3, PEX3, and PEX5L, during peak viral production, which was accompanied by reduced expression of IFNB, IRF3, IRF1, and MAVS, particularly in ΔNS2-infected cells. These data were consistent with analyses of brain tissue from patients infected with HPgV in which we observed suppression of peroxisome and type I interferon gene transcripts, including PEX11B, ABCD3, IRF1, and IRF3, with concurrent loss of PMP70 immunoreactivity in glia. Our data indicate that human astrocytes and microglia are permissive to HPgV infection, resulting in peroxisome injury and suppressed antiviral signaling that is influenced by viral diversity. IMPORTANCE Human pegiviruses are detected in 1 to 5% of the general population, principally infecting leukocytes, although their effects on human health remain uncertain. Here, we show that human pegivirus infects specific neural cell types in culture and human brain and, like other neurotropic flaviviruses, causes suppression of peroxisome and antiviral signaling pathways, which could favor ongoing viral infection and perhaps confer susceptibility to the development of neurological disease.

Absent in melanoma 2 regulates tumor cell proliferation in glioblastoma multiforme.

INTRODUCTION: Inflammation is a key aspect of glioblastoma multiforme (GBM) although it remains unclear how it contributes to GBM pathogenesis. Inflammasomes are intracellular multi-protein complexes that are involved in innate immunity and are activated by cellular stress, principally in macrophages. This study examined the expression of inflammasome-associated genes in GBM, particularly absent in melanoma 2 (AIM2). METHODS: Tissue samples from surgically-resected GBM tumors (n = 10) were compared to resected brain specimens from patients with epilepsy (age- and sex-matched Other Disease Controls (ODC, n=5)) by qRT-PCR, western blotting and immunofluorescence. Gene expression studies in human astrocytoma U251 cells were performed and the effects of deleting the absent in melanoma 2 (AIM2) gene using the CRISPR-Cas9 system were analyzed. RESULTS: GBM tissues showed significantly elevated expression of multiple immune (CD3E, CD163, CD68, MX1, ARG1) and inflammasome (AIM2, NLRP1, IL18, CASP1, and IL-33) genes compared to ODC tissues, without induction of IL1B, IFNG or TNFA. An insert-containing AIM2 variant transcript was highly expressed in GBM tissues and in U251 cells. AIM2 immunoreactivity was concentrated in the tumor core in the absence of PCNA immunodetection and showed a predominant 52 kDa immunoreactive band on western blot. Deletion of AIM2 resulted in significantly enhanced proliferation of U251 cells, which also displayed increased resistance to temozolomide treatment. CONCLUSIONS: GBM tumors express a distinct profile of inflammasome-associated genes in a tumor-specific manner. AIM2 expression in tumor cells suppressed cell proliferation while also conferring increased susceptibility to contemporary GBM therapy.

Rapid Multifocal Neurologic Decline in an Immunocompromised Patient.

A man in his early 70s with a diagnosis of chronic lymphocytic leukemia and being treated with prednisone, fludarabine, cyclophosphamide, and rituximab presented with progressive multifocal neurologic decline. The patient died 2 months after the onset of this decline despite extensive clinical and laboratory investigation and a trial of methylprednisolone therapy. The approach to the immunosuppressed patient with progressive neurologic decline, neuropathologic findings, and final diagnosis are discussed.

Confocal neurolasermicroscopy in human brain - perspectives for neurosurgery on a cellular level (including additional comments to this article).

BACKGROUND: During neurosurgery intraoperative imaging of vital neural structures on a cellular level would facilitate the development of new strategies for diagnosis and treatment. In vivo imaging would permit the detection of the tumour centre and infiltration zone. With targeted biopsies the lesion of interest could be determined before performing the biopsy, facilitating the final pathological diagnosis. In this study we present confocal neurolasermicroscopy as a new method in neurosurgery. METHODS: A miniaturised confocal neurolasermicroscope (NLM) was used ex vivo immediately after tumour resection of glioblastoma multiforme (GBM). NLM was performed with subcellular magnification up to a tissue depth of 100 microm. NLM images were compared to conventional histological images of the same tumour. RESULTS: The application of the method in nine patients allowed adequate diagnosis of a malignant glioma fulfilling the WHO criteria when compared to conventional histology. In one patient with glioblastoma multiforme NLM allowed the correct diagnosis of GBM to be made, demonstrating the high mitotic rate and cell pleomorphy of the tumour cells. Additional characteristics such as pleomorphic cells, mitotic figures, fibrillary matrix and the distinction between tumour centre and infiltration zone could be shown. CONCLUSIONS: NLM is a tool which could be adapted for neurosurgical intraoperative applications with the potential to diagnose tumours and recognise the tumour centre and infiltration zone in vivo. Further applications of NLM to characterise subcellular structures and vascular architecture are possible.

[Neurotuberculosis: a continuing clinical challenge]. / Neurotuberkulose : Eine anhaltende klinische Herausforderung.

In Germany neurotuberculosis is quite rare. Familiarity with the disease is nonetheless important because of many differential diagnoses and therapeutic implications. The diagnosis of neurotuberculosis is made by considering of clinical presentation, CSF, and cerebral imaging. Early diagnosis, prompt initiation of effective antitubercular therapy, and clinical staging are necessary for establishing a long-term treatment prognosis. The results of neurotuberculosis therapy are often unsatisfactory despite the availability of effective drugs. Lasting damage or death can be averted in fewer than half of the patients. Studies now confirm that early adjuvant corticoid therapy reduces lethality and morbidity. Resistant new strains of the pathogen, Mycobacterium tuberculosis, complicate therapy. Recent discoveries especially in diagnosis and therapy are explained using case evidence.

[Progressive muscle atrophy. A rarely diagnosed variant of amyotrophic lateral sclerosis]. / Progressive Muskelatrophie. Eine unterdiagnostizierte Variante der amyotrophen Lateralsklerose.

Progressive muscle atrophy (PMA) is a degenerative disease of the lower motor neuron. The course of the illness and the fatal prognosis correspond to those of amyotrophic lateral sclerosis (ALS). Neuropathologic and genetic findings support categorizing PMA within the spectrum of ALS, even though no clinical sign of a disorder of the upper motor neuron is demonstrable. The diagnosis of PMA is based on advanced extremity pareses and atrophies with a high progression rate. Respiratory insufficiency is determinative of the prognosis. Absent or late affection of bulbar functions is characteristic of the disease. Intraneuronal bunina bodies and ubiquitine-positive inclusions, which are established morphologic characteristics of ALS, are found post mortem. The treatment options of riluzol medication, respiratory therapy, and nutrition are analogous to those for typical ALS.

Muscle and nerve pathology in Dunnigan familial partial lipodystrophy.

OBJECTIVE: To characterize muscle and nerve pathology in Dunnigan familial partial lipodystrophy (FPLD). METHODS: We used conventional histology, immunohistochemistry, messenger RNA (mRNA) expression, gene sequencing, and clinical studies of 13 patients with neuromuscular involvement. RESULTS: The clinical findings consisted of muscle hypertrophy (12/13), severe myalgias (9/13), and multiple nerve entrapment syndromes (8/13). Skeletal muscle histology demonstrated marked Type 1 and 2 muscle fiber hypertrophy and nonspecific myopathic changes, whereas numerous paranodal myelin swellings (tomacula) were found in sural nerve biopsies. We found that myostatin mRNA expression was reduced in patients with FPLD vs controls. We sequenced the myostatin gene in our subjects, but found no mutations. We then investigated whether or not SMAD, the intracellular mediator of myostatin signaling, might be impaired in patients with FPLD. We found that in FPLD muscle, a large number of SMAD molecules adhered to the nuclear membrane and were not found within the nucleus, compared with normal muscle or muscle from a patient with a non-FPLD lamin A/C disease. CONCLUSION: The myopathy and neuropathy associated with Dunnigan familial partial lipodystrophy are distinct from other lamin A/C disorders. We hypothesize that the lipodystrophy-associated mutation interferes with SMAD signaling, linking this type of lipodystrophy to the phenotypically similar myostatin deficiency.

[Polyarteritis nodosa - a "classical" case]. / Panarteritis nodosa - ein "klassischer" Fall.

Diagnosis of polyarteritis nodosa is often delayed due to the vast heterogeneity of initial clinical symptoms. The case presented shows the clinical image of the disease, leading from the first symptoms up to verification of the diagnosis by sural-nerve biopsy. We discuss the classification of the disease among other types of vasculitis, the classification criteria proposed by the American College of Rheumatology (ACR) as well as current therapeutic options. This case underlines the interdisciplinary character of the disease, challenging neurologists, dermatologists, rheumatologists and orthopedics alike.

Plastic bronchitis in children with Fontan palliation: analogue to protein losing enteropathy?

We studied a 6-year-old boy and a 2-year-old girl with bronchitis fibroplastica following Fontan operation. Large endobronchial casts of rubber-like consistency resulted in life-threatening pulmonary failure. In one patient symptoms improved after optimizing heart function with diuretics, and in the other a dramatic improvement with the resolution of the clinical symptoms and normalized serum albumin followed subcutaneous high-molecular-weight heparin treatment. The severe relapse after discontinuation of the heparin medication and the once more successful treatment with heparin suggest that in addition to optimizing heart function, high-molecular-weight heparin might be a therapeutic option for this poorly understood condition.

Early expression of glutamate transporter proteins in ramified microglia after controlled cortical impact injury in the rat.

Traumatic brain injury is followed by increased extracellular glutamate concentration. Uptake of glutamate is mainly mediated by the glial glutamate transporters GLAST and GLT-1. Extent and distribution of GLAST and GLT-1 were studied in a rat model of controlled cortical impact injury (CCII). Western Blot analysis revealed lowest levels of GLAST and GLT-1 with a decrease by 40%-54% and 42%-49% between 24 and 72 h posttrauma. By 8 h after CCII, CSF glutamate levels were increased (10.5 microM vs. 2.56 microM in controls; P < 0.001), reaching maximum values by 48 h. A significant increase in de novo GLAST and GLT-1 expressing ramified microglia was observed within 4 h, reached a stable level by 48 h, and remained high up to 72 h after CCII. Furthermore, ramified microglia de novo expressed the neuronal glutamate transporter EAAC1 after CCII. Following CCII, GLAST/GLT-1 and GFAP coexpressing astrocytes were immediately reduced, reaching minimum levels within 8 h. This reduction of expression could be either due to protein downregulation or loss of astrocytes. At 72 h, a marked population of GLAST- and GLT-1-positive reactive astrocytes appeared. These results support the hypothesis that reduced astrocytic GLAST and GLT-1 protein levels following CCII contribute to evolving secondary injury. Microglia are capable of de novo expressing glutamate transporter proteins, indicating that the expression of glial and neuronal glutamate transporters is not restricted to a specific glial or neuronal lineage. Ramified microglia may play an important compensatory role in the early regulation of extracellular glutamate after CCII.

Heterozygous myogenic factor 6 mutation associated with myopathy and severe course of Becker muscular dystrophy.

Myogenic factors (MYF) belong to the basic helix-loop-helix (bHLH) transcription factor family and regulate myogenesis and muscle regeneration. The physiological importance of both functions was demonstrated in homozygous Myf knockout mice and mdx mice. Myf5 and Myod are predominantly expressed in proliferating myoblasts while Myf4 and Myf6 are involved in differentiation of myotubes. In a boy with myopathy and an increase of muscle fibres with central nuclei we detected a heterozygous 387G-->T nucleotide transversion in the MYF6 gene (MIM*159991). Protein-protein interaction of mutant MYF6 was reduced, and DNA-binding potential and transactivation capacity were abolished, thus demonstrating MYF6 haploinsufficiency. The boy's father carried the identical mutation and, in addition, an in-frame deletion of exons 45-47 in his dystrophin gene. This mutation is normally associated with a mild to moderate course of Becker muscular dystrophy but the father suffered from a severe course of Becker muscular dystrophy suggesting MYF6 as a modifier.

Aqueductal stenosis and hydrocephalus in an infant due to aspergillus infection.

Aqueductal stenosis is a common cause of hydrocephalus during infancy. We report on an infant born with aplasia cutis congenita at the scalp vertex and hypoplastic left heart syndrome developing systemic aspergillosis after cardiac surgery. The infant died at the age of 76 days despite systemic antimycotic therapy with a combination of flucytosine and amphotericin B. Therapy started at post-operative day 17 and was also applied intrathecally. Post-mortem examination revealed meningitis, multiple brain aspergillomas and microabscesses with focal ependymitis, focal bronchopneumonia, and necrotizing enterocolitis. One of the brain aspergillomas was located close to the aqueduct causing an aqueductal stenosis and an obstructive hydrocephalus. Histologically, aspergillus hyphae could only be detected in the aspergilloma of the aqueduct. To the best of our knowledge, this is the first reported case of an aqueductal stenosis caused by an aspergilloma.

Dystrophinopathy in a boy with Chediak-Higashi syndrome.

Chediak-Higashi syndrome (CHS) is a hereditary, biphasic immunodeficiency syndrome which usually leads to early death, during the first decade. The second phase is characterized by a lymphoproliferative syndrome with histiocytic infiltrations in various tissues. Recently the gene has been identified on chromosome 1q43. In the patient presented here, a mutation within codon 3197 was found, resulting in a frame-shift. Additionally, Duchenne muscular dystrophy (DMD) was diagnosed by immunostaining of the muscle. Unusual for both CHS and DMD muscle weakness and hypotonia became evident during the first months of life. Compared to typical DMD cases we found an increased histiocytic infiltration in the muscle. The underlying muscular dystrophy probably predisposes to the affection of muscle in the second phase of CHS. This patient is presented as an example of modification of the phenotype by a second genetic disease.

Basement membrane thickness of the vocal cord in cases of sudden infant death.

In 1991, 1994 and 1997 Shatz et al. reported on a specific and pathognomonic basement membrane (BM) thickening of the vocal cord in cases of sudden infant death syndrome (SIDS). In 40 cases of sudden and unexpected infant death the histological examination of the larynx was performed to identify possible differences between SID (n=26) and non-SID (n=14) cases. The dissection technique of Hohmann (1963) and Maxeiner (1986) was modified for the infant's larynx. Since the normal range of the BM thickness of the vocal cord for the age group younger than 1 year had not yet been exactly defined, a reference interval had to be established (0.5 microm-2.0 microm). In 2 SID and 1 non-SID cases a mean BM thickness (BMT) of more than 2.0 microm could be estimated (2.38 microm-2.95 microm). The BMT in these cases appeared to be highly variable and not harmonically thickened. None of the investigated regions of the BM (cranial to caudal thirds, ventral to dorsal areas) seemed to be preferred thickened. There was no statistically significant difference between the two groups. A specific thickening of the BM of the vocal cord in SID cases could not be confirmed. Therefore, BMT cannot be used as a diagnostic postmortem marker for SID.