Retropharyngeal lymph nodes in children: a common imaging finding and potential source of misinterpretation.

Objective: The retropharyngeal lymph nodes are the least well-described portion of the Waldeyer ring. Originally described as occurring in medial and lateral groups, reports have described only the presence of lateral nodes in children. We have seen cases of MRI sleep studies in children with obstructive sleep apnea (OSA) in which lateral and medial retropharyngeal lymph nodes are present and have been misinterpreted.

Resistance to Citrus psorosis virus in transgenic sweet orange plants is triggered by coat protein-RNA silencing.

The lack of naturally occurring resistance to Citrus psorosis virus (CPsV) has demanded exploitation of a transgenic approach for the development of CPsV-resistant sweet orange plants. Transgenic sweet orange plants producing intron-hairpin RNA transcripts (ihpRNA) corresponding to viral cp, 54K or 24K genes were generated and analyzed at the molecular and phenotypic levels. Two independent CPsV challenge assays demonstrated that expression of ihpRNA derived from the cp gene (ihpCP) provided a high level of virus resistance, while those derived from 54K and 24K genes (ihp54K and ihp24K) provided partial or no resistance.

Superior cervical extension of the thymus: a normal finding that should not be mistaken for a mass.

Purpose: To determine the proportion of children and young adults in whom the thymus extends superiorly above the level of the manubrium into the anterior cervical tissues on magnetic resonance (MR) imaging studies.

Materials And Methods: This retrospective study was approved by the institutional review board, and written consent was waived. Sagittal proton density-weighted images from MR imaging examinations of the neck and upper chest were obtained for various indications in 200 consecutive patients (121 male and 79 female; mean age, 9.

Population structure of Citrus tristeza virus from field Argentinean isolates.

We studied the genetic variability of three genomic regions (p23, p25 and p27 genes) from 11 field Citrus tristeza virus isolates from the two main citrus growing areas of Argentina, a country where the most efficient vector of the virus, Toxoptera citricida, is present for decades. The pathogenicity of the isolates was determinated by biological indexing, single-strand conformation polymorphism analysis showed that most isolates contained high intra-isolate variability. Divergent sequence variants were detected in some isolates, suggesting re-infections of the field plants.

Genetic transformation of sweet orange with the coat protein gene of Citrus psorosis virus and evaluation of resistance against the virus.

Citrus psorosis is a serious viral disease affecting citrus trees in many countries. Its causal agent is Citrus psorosis virus (CPsV), the type member of genus Ophiovirus. CPsV infects most important citrus varieties, including oranges, mandarins and grapefruits, as well as hybrids and citrus relatives used as rootstocks.