MRI Predictors of Recurrence and Outcome after Acute Transverse Myelitis of Unidentified Etiology.

BACKGROUND AND PURPOSE: The early prediction of recurrence after an initial event of transverse myelitis helps to guide preventive treatment and optimize outcomes. Our aim was to identify MR imaging findings predictive of relapse and poor outcome in patients with acute transverse myelitis of unidentified etiology. MATERIALS AND METHODS: Spinal MRIs of 77 patients (mean age, 36.3 ± 20 years) diagnosed with acute transverse myelitis were evaluated retrospectively. Only the patients for whom an underlying cause of myelitis could not be identified within 3 months of symptom onset were included. Initial spinal MR images of patients were examined in terms of lesion extent, location and distribution, brain stem extension, cord expansion, T1 signal, contrast enhancement, and the presence of bright spotty lesions and the owl's eyes sign. The relapse rates and Kurtzke Expanded Disability Status Scale scores at least 1 year (range, 1-14 years) after a myelitis attack were also recorded. Associations of MR imaging findings with clinical variables were studied with univariate associations and binary log-linear regression. Differences were considered significant for P values < .05. RESULTS: Twenty-seven patients (35.1%) eventually developed recurrent disease. Binary logistic regression revealed 3 main significant predictors of recurrence: cord expansion (OR, 5.30; 95% CI, 1.33-21.11), contrast enhancement (OR, 5.05; 95% CI, 1.25-20.34), and bright spotty lesions (OR, 3.63; 95% CI, 1.06-12.43). None of the imaging variables showed significant correlation with the disability scores. CONCLUSIONS: Cord expansion, contrast enhancement, and the presence of bright spotty lesions could be used as early MR imaging predictors of relapse in patients with acute transverse myelitis of unidentified etiology. Collaborative studies with a larger number of patients are required to validate these findings.

Radiation-Induced Myelitis: Initial and Follow-Up MRI and Clinical Features in Patients at a Single Tertiary Care Institution during 20 Years.

Myelitis is a rare complication of radiation exposure to the spinal cord and is often a diagnosis of exclusion. A retrospective review of clinical records and serial imaging was performed to identify subjects with documented myelitis and a history of prior radiation. Eleven patients fulfilled the inclusion criteria. All patients had longitudinally extensive cord involvement with homogeneous precontrast T1 hyperintense signal in the adjacent vertebrae, corresponding to the radiation field. T2 signal abnormalities involving the central two-thirds of the cord were seen in 6/11 patients (55%). The degree of cord expansion and contrast enhancement was variable but was seen in 6 (54%) and 5 (45%) patients, respectively. On follow-up, 2 patients developed cord atrophy, while complete resolution was noted in 1. Clinical improvement was noted in 5 patients, with symptom progression in 2 patients. Our results suggest that radiation myelitis is neither universally progressive nor permanent, and some radiographic and clinical improvement may occur.

Genomic analysis of filoviruses associated with four viral hemorrhagic fever outbreaks in Uganda and the Democratic Republic of the Congo in 2012.

In 2012, an unprecedented number of four distinct, partially overlapping filovirus-associated viral hemorrhagic fever outbreaks were detected in equatorial Africa. Analysis of complete virus genome sequences confirmed the reemergence of Sudan virus and Marburg virus in Uganda, and the first emergence of Bundibugyo virus in the Democratic Republic of the Congo.

Sin Nombre virus glycoprotein trafficking.

Sin Nombre virus (SNV) is a major representative of the New World hantaviruses and the most common cause of hantavirus pulmonary syndrome (HPS) with high mortality in North America. Unlike other members of the family Bunyaviridae which mature in the Golgi complex, New World hantaviruses have been previously reported to mature at the cell surface. For family Bunyaviridae viruses, retention of the viral glycoproteins at the Golgi complex is thought to be responsible for their Golgi maturation. In our studies, the majority of SNV glycoproteins, G1 and G2, was localized in the Golgi complex when expressed from a full-length GPC clone or in SNV-infected cells, in agreement with data for other members of the family Bunyaviridae, including the Old World hantaviruses. However, the SNV glycoproteins could also be detected at the cell surface at advanced posttransfection or postinfection time points. G1 expressed in the absence of G2 did not accumulate in the Golgi, but remained predominantly associated with the endoplasmic reticulum (ER). Overexpressed amounts of apparently misfolded G1 were aggregated in a subcellular compartment likely to represent the aggresome. Unexpectedly, an additional major pool of G1 was detected intracellularly in SNV-infected and GPC-expressing transfected cells, by using a SNV G1-specific Fab antibody. This pool of G1 is predominantly localized in late endosomes-lysosomes.

Characterization of the major nuclear localization signal of the Borna disease virus phosphoprotein.

Borna disease virus (BDV) replicates and transcribes its negative-sense RNA genome in the nucleus. The BDV phosphoprotein (P) is localized in the nucleus of infected cells and cells transfected with P expression constructs. To identify the nuclear localization signal (NLS) of P, COS-7 cells were transfected with wild-type or mutant forms of P fused with green fluorescent protein (GFP). Whereas GFP alone was exclusively cytoplasmic, P or P-GFP were nuclear. Analysis of carboxy- and amino-terminal truncation mutants of P indicated that amino acids (aa) 20-37 are sufficient to promote efficient nuclear accumulation of the fusion protein. Residual nuclear import of GFP was observed with portions of P including aa 33-134 or aa 134-201, suggesting the presence of additional NLS motifs. The major NLS of P appears to be bipartite. It consists of two basic aa domains, R22RER25 and R30PRKIPR36, separated by four non-basic aa, S26GSP29.

Exclusion of bacteriophage T1 by bacteriophage lambda. II. Synthesis of T1-specific macromolecules under N-mediated excluding conditions.

The results of experiments investigating T1 macromolecular synthesis under N-mediated excluding conditions failed to demonstrate a substantial alteration in the T1 mRNA production in excluding cultures at any stage in the T1 infectious cycle. The number of T1 DNA sequences in the excluding culture was found to be one-third to one-half that found in T1-infected cultures. The most severe reduction in T1-specific macromolecules was seen in protein synthesis. Total incorporation of labeled amino acids was reduced sixfold, and gel experiments confirmed that the T1-specific proteins capable of detection are reduced in excluding cells.