Development of a Bead-Based Multiplex Fluorescent Immunoassay to Detect Antibodies against Maedi-Visna Virus in Sheep.

The Maedi-visna virus (MVV) causes a persistent infection in small ruminants, and its high genetic heterogeneity affects the performance of diagnostic tests when used in different populations. Therefore, the aim of this study was to develop a bead-based multiplex immunoassay tailored to detect antibodies against a Norwegian MVV strain. We used tissue samples from 14 PCR-positive sheep from a recent MVV outbreak in Norway to sequence the viral strain and produced recombinant antigens based on sequences from one animal. The assay included commercial TM-A and recombinant Norwegian p25, p16-25 and SU5 antigens. Cut-off values for each antigen were determined using receiver operating characteristic curves on 40 ELISA-negative and 67 ELISA-positive samples from the outbreak. The intraplate and interplate repeatability were investigated by testing a quadruplicate of five samples over three days, while the analytical sensitivity (aSe) and specificity (aSp) were measured in comparison to a commercial ELISA. The repeatability showed a coefficient of variation below 15% for most positive samples. The aSe was equal or higher for the multiplex assay than the ELISA, and the aSp of each antigen was 91.7, 93.3, 95.0 and 93.3% for p25, p16-25, SU5 and TM-A, respectively. The assay shows promising results; however, further evaluations of diagnostic characteristics are necessary before implementation in the Norwegian surveillance programme.

Cranial Ultrasound as a First-Line Imaging Examination for Craniosynostosis.

BACKGROUND: Radiography, typically the first-line imaging study for diagnosis of craniosynostosis, exposes infants to ionizing radiation. We aimed to compare the accuracy of cranial ultrasound (CUS) with radiography for the diagnosis or exclusion of craniosynostosis. METHODS: Children aged 0 to 12 months who were assessed for craniosynostosis during 2011-2013 by using 4-view skull radiography and CUS of the sagittal, coronal, lambdoid, and metopic sutures were included in this prospective study. Institutional review board approval and parental informed consent were obtained. CUS and radiography were interpreted independently and blindly by 2 pediatric radiologists; conflicts were resolved in consensus. Sutures were characterized as closed, normal, or indeterminate. Correlation between CUS and radiography and interreader agreement were examined for each suture. RESULTS: A total of 126 children (82 boys, 64.5%) ages 8 to 343 days were included. All sutures were normal on CUS and radiography in 115 patients (93.7%); craniosynostosis of 1 suture was detected in 8 (6.3%, 5 sagittal, 2 metopic, 1 coronal). In 3 cases the metopic suture was closed (n = 2) or indeterminate on CUS (n = 1) but normally closed on radiography. CUS sensitivity was 100%, specificity 98% (95% confidence interval 94%-100%). Reader agreement was 100% for sagittal, coronal, and lambdoid sutures (κ = 0.80); after consensus, disagreement remained on 3 metopic sutures. CONCLUSIONS: In this series, CUS could be safely used as a first-line imaging tool in the investigation of craniosynostosis, reducing the need for radiographs in young children. Additional assessment may be required for accurate assessment of the metopic suture.

The necessity of shunt series.

OBJECT: This work assessed the value of shunt series in the evaluation of children with CSF shunts, a test that is frequently ordered as part of the assessment of shunt integrity. METHODS: The medical records of all children who underwent shunt series at Children's Hospital of Eastern Ontario between 1975 and 2007 were reviewed. Ancillary studies that were performed within 2 days of the shunt series (brain CT, MR imaging, ultrasonography, and radionuclide shuntography) were noted, as well as the subsequent requirement for a shunt revision. Shunt series and ancillary studies were categorized as either positive (revealing an observable sign that a shunt-related problem was present, such as shunt discontinuity on the shunt series or enlargement of the ventricles on the brain CT scan) or negative (no clear sign of a shunt-related problem). Shunt series were further grouped into shunt series performed for diagnostic reasons, shunt series performed on a routine basis during follow-up in clinic, and shunt series performed postoperatively. The length of time between shunt insertion and shunt fracture was noted. Statistical analyses were performed, including the derivation of sensitivities and specificities. RESULTS: There were 3416 shunt series in 394 patients, of which 3004 were performed with ancillary studies. On average, patients underwent 9 shunt series, with a minimum of 1 and a maximum of 43, during the follow-up period (range 3 weeks to 19 years). A total of 2493 shunt series and ancillary studies (83%) yielded negative results and no surgery was performed. One hundred thirty shunts series were negative with a positive ancillary study (4.3%) and no surgery was required. In 8.7% (261 shunt series negative, ancillary studies positive) shunt revision surgery was necessary. The opposite trend was far less prevalent (17 shunt series positive, ancillary test negative; 0.6%) in which surgery was required. There were 87 patients with 96 shunt fractures (2.8% of shunt series). The average time between shunt insertion and shunt fracture was 7.9 years (range 3 months to 18 years). Shunt series had a sensitivity of 18% and a specificity of 97%. The ancillary studies had a sensitivity of 84% and a specificity of 85%. CONCLUSIONS: The routine utilization of shunt series in the evaluation of a child with a CSF shunt is not necessary. This study showed that a very small number (0.6%) of shunt series helped in surgical decision making. Shunt series can be performed in selected cases, especially preoperatively in the absence of a baseline study to obtain information necessary for surgical planning.

Acute encephalopathy and cerebral vasospasm after multiagent chemotherapy including PEG-asparaginase and intrathecal cytarabine for the treatment of acute lymphoblastic leukemia.

A 7-year-old girl with an unusual reaction to induction chemotherapy for precursor B-cell acute lymphoblastic leukemia (ALL) is described. The patient developed acute encephalopathy evidenced by behavioral changes, aphasia, incontinence, visual hallucinations, and right-sided weakness with diffuse cerebral vasospasm on magnetic resonance angiography after the administration of intrathecal cytarabine. Vincristine, dexamethasone, and polyethylene glycol-asparaginase were also administered before the episode as part of induction therapy. Neurologic status returned to baseline within 10 days of the acute event, and magnetic resonance angiography findings returned to normal 4 months later.

Pseudo-tumoral eosinophilic cystitis in a 3 year-old girl.

Eosinophilic cystitis (EC) is an uncommon form of bladder inflammation. It is a rare disorder in children and fewer than 25 cases have been described in the literature. We report a case of eosinophilic cystitis mimicking a bladder tumor in a 3 year-old girl with symptoms of urinary frequency. The diagnosis was confirmed with pathology and she underwent clinical treatment with corticosteroids.