A whole genome perspective on the phylogeny of the plant virus family Tombusviridae.

Most current classifications of viruses are based on single gene analysis of capsid protein or polymerase. The comparison of entire genomes is a more balanced approach that should provide a more complete picture of relatedness. We have used a singular value decomposition (SVD)-based analysis to generate phylogenetic trees using whole genome protein sequences from a family of single-stranded RNA plant viruses. Our dataset includes the 26 species of the family Tombusviridae, 25 of which have complete genome sequences cataloged in GenBank. The resulting phylogenetic tree agrees well with current taxonomic classifications, but with significant exceptions. One previously unassigned virus within this family, Maize necrotic streak virus, is definitively placed within the genus Tombusvirus by this analysis. In addition, the analysis defines two distinct subsets within the genus Necrovirus. Future datasets will be expanded to include other icosahedral positive strand RNA plant viruses, and then perhaps all positive strand RNA plant viruses.

Regioselective and enantiospecific rhodium-catalyzed allylic amination with N-(arylsulfonyl)anilines.

[reaction: see text]. The regioselective and enantiospecific rhodium-catalyzed allylic amination of secondary allylic carbonates 1 with N-(arylsulfonyl)anilines provides a convenient process for the construction of arylamines 2. This method, in conjunction with ring-closing metathesis and radical cyclization reactions, allows the direct construction of biologically relevant pharmacophores as exemplified by the construction of dihydroquinoline and dihydrobenzo[b]indoline derivatives.

Dynamic tissue expansion of the larynx in a canine model.

OBJECTIVES: To test whether staged, progressive, monitored, dynamic tissue expansion is possible in the larynx and to evaluate its effectiveness in dilating and augmenting constricting cicatricial lesions. DESIGN: Animal study. SETTING: Research facility, tertiary care medical center. SUBJECTS: Thirteen dogs, 3 with laryngotracheal stenosis. INTERVENTIONS: Dogs underwent laryngeal splits, tracheostomy, and insertion of inflatable stents. In 7 normal dogs, stents were progressively inflated by air in predetermined increments during 11 days. In 3 normal dogs and 3 with laryngotracheal stenosis, stents were gradually expanded by water. Stents were kept in place for 21 days. After removal, dogs were observed for 25 days. Five died of complications of tracheostomy. MAIN OUTCOME MEASURES: Airway diameter measured by endoscopy before the induction of stenosis, before the laryngeal splitting procedure, after stent removal, and before euthanasia. RESULTS: The lumen increased, then shrank somewhat after stent removal. In 2 surviving dogs with laryngotracheal stenosis and water-expanded stents, the lumen was 82.5% larger than baseline at stent removal and 71.0% larger at euthanasia. In 2 surviving normal dogs with water-expanded stents, lumen size increased by 50.0% at stent removal, and in 1 dog surviving to day 46, it was 17.0% larger. In 5 surviving dogs with air-inflated stents, lumen size was 39.0% larger at stent removal and 8.0% larger at day 46. Histologically, fibrous tissue developed in the gaps between the splayed margins of the laryngeal cartilages. CONCLUSIONS: The larynx may be dynamically expanded. Although the maximal diameter is not maintained, final cross-sectional areas are larger.

Evaluating laryngotracheal stenosis in a canine model with virtual bronchoscopy.

We performed a prospective masked animal study to determine whether virtual bronchoscopy, a noninvasive computed tomography technique, can accurately measure upper airway stenosis. Virtual bronchoscopy creates a 3-dimensional endoscopic image from spiral computed tomography data. Laryngotracheal stenosis was endoscopically induced in 18 dogs. The excised larynges were examined by endoscopy, virtual bronchoscopy, and macrodissection. Measurements were made of the anteroposterior (A-P) diameter, the left-right (L-R) diameter, the full length of stenosis in the sagittal plane, and the length of the tightest stenotic segment. Each measurement method was performed independently. All investigators were unaware of measurements made by others. The measurements obtained through virtual bronchoscopy and actual endoscopy were compared to those made at dissection by interclass correlation coefficients (ICCs). Endoscopy was better than virtual bronchoscopy in measuring the A-P diameter (ICC = .79, p < .0001; ICC = .42, p = .01). Both were equally effective in measuring the L-R diameter (ICC = .53, p = .0062; ICC = .52, p = .0064). The endoscopes could not assess the full length of the stenosis, whereas virtual bronchoscopy measured it fairly accurately (ICC = .72, p = .0001). Virtual bronchoscopy relatively accurately measured the length of the tightest stenotic segment (ICC = .68, p = .0002), whereas endoscopy produced measurements in only 11 of 18 larynges, and the measurements were less accurate (ICC = .45, p = .0068). Virtual bronchoscopy can provide good measurements of stenotic lesions in the airway. It is more accurate than actual endoscopy in determining the length of stenosis. It may therefore be useful as an adjunct imaging method in preoperative planning for reconstructive surgery.

Quadriplegia complicating Escherichia coli meningitis in a newborn infant: case report and review of 22 cases of spinal cord dysfunction in patients with acute bacterial meningitis.

We report a case of Escherichia coli meningitis complicated by spinal cord dysfunction in a neonate. This very rare complication of bacterial meningitis was probably caused by ischemia of the cord resulting from vasculitis. We review the 22 other reports of patients with this complication and discuss its pathogenesis.

Liquid chromatographic determination of thiamine in infant formula products by using ultraviolet detection.

A liquid chromatographic (LC) method has been developed for determination of thiamine in infant formula products. The method involves the following steps: (a) dissolution of the formula with water, (b) pH adjustment to induce protein precipitation, (c) filtration, (d) concentration of thiamine by using a cation exchange column and extraction system, (e) cleanup of adsorbed thiamine and other contaminants on the ion exchange column by washing with water and then methanol, (f) elution of thiamine with a mixture of methanol-2M potassium chloride buffer, (g) analysis for thiamine by liquid chromatography. Thiamine is separated from its phosphate esters, the mono-, di-, and triphosphates, as well as its antagonists oxythiamine and pyrithiamine on a 6 micron particle size column and a mobile phase of 40mM triethyl-ammonium phosphate buffer-methanol (pH 7.7) (90 + 10). The method is reproducible, with relative standard deviations ranging from +/- 0.76 to +/- 1.2%, depending on the infant formula product tested. Recovery of thiamine from various infant formula products is greater than 99%. Analysis for thiamine of several commercially available infant formulas at different levels of fortification gave results that ranged from 122 to 216% of the declared levels. These results agree well with those obtained using the AOAC fluorometric method.