Association of Excess Weight and Degree of Airway Responsiveness in Asthmatics and Non-Asthmatics

It is unclear whether obesity is associated with increasing degree of airway responsiveness in asthmatics. In this study, methacholine challenge test results of 1,725 subjects with respiratory symptoms were reviewed. Obesity was associated with asthma with an odds ratio of 1.72 (95% C.I. 1.36, 2.17). Although there was a significant difference in the degree of airway responsiveness between various body mass index categories of non-asthmatics (p = 0.01), no significant difference was noted among asthmatics (p = 0.93). A weakly significant interaction between asthma status and body mass index on the degree of airway responsiveness was noted (p = 0.08).     

Study of the Variability in Upper and Lower Airway Morphology in Sprague–Dawley Rats Using Modern Micro‐CT Scan‐Based Segmentation Techniques

Animal models are being used extensively in pre‐clinical and safety assessment studies to assess the effectiveness and safety of new chemical entities and delivery systems. Although never entirely replacing the need for animal testing, the use of computer simulations could eventually reduce the amount of animals needed for research purposes and refine the data acquired from the animal studies. Computational fluid dynamics is a powerful tool that makes it possible to simulate flow and particle behavior in animal or patient‐specific respiratory models, for purposes of inhaled delivery. This tool requires an accurate representation of the respiratory system, respiration and dose delivery attributes. The aim of this study is to develop a representative airway model of the Sprague–Dawley rat using static and dynamic micro‐CT scans. The entire respiratory tract was modeled, from the snout and nares down to the central airways at the point where no distinction could be made between intraluminal air and the surrounding tissue. For the selection of the representative model, variables such as upper airway movement, segmentation length, airway volume and size are taken into account. Dynamic scans of the nostril region were used to illustrate the characteristic morphology of this region in anaesthetized animals. It could be concluded from this study that it was possible to construct a highly detailed representative model of a Sprague–Dawley rat based on imaging modalities such as micro‐CT scans. Anat Rec, 2009. © 2009 Wiley‐Liss, Inc.     

Comparison of dual to single contrast bolus magnetic resonance myocardial perfusion imaging for detection of significant coronary artery disease

Purpose:

To investigate the incremental diagnostic value of dual‐bolus over single‐contrast‐bolus first pass magnetic resonance myocardial perfusion imaging (MR‐MPI) for detection of significant coronary artery disease (CAD).

Materials and Methods:

Patients (n = 49) with suspected CAD underwent first pass adenosine stress and rest MR‐MPI and invasive coronary angiography (CA). Gadolinium diethylenetriamine pentaacetic acid (Gd‐DTPA) was injected with a prebolus (1 mL) and a large bolus (0.1 mmol/kg). For the single‐bolus technique, the arterial input function (AIF) was obtained from the large‐contrast bolus. For the dual‐bolus technique, the AIF was reconstructed from the prebolus. Absolute myocardial perfusion was calculated by Fermi‐model constrained deconvolution. Receiver operating characteristic (ROC) analysis was used to investigate diagnostic accuracy of MR myocardial perfusion imaging for detection of significant CAD on CA at vessel‐based analysis.

Results:

The area under the curve (AUC) of the minimal stress perfusion value for the detection of significant CAD using the single‐bolus and dual‐bolus technique was 0.85 ± 0.04 (95% confidence interval [CI], 0.77–0.93) and 0.77 ± 0.05 (95% CI, 0.67–0.86), respectively.

Conclusion:

In this study the dual‐bolus technique had no incremental diagnostic value over single‐bolus technique for detection of significant CAD with the used contrast concentrations. J. Magn. Reson. Imaging 2010;32:88–93. © 2010 Wiley‐Liss, Inc.     

Sensitivity and specificity of the Leishmania OligoC‐TesT and NASBA‐oligochromatography for diagnosis of visceral leishmaniasis in Kenya

Objective To estimate the sensitivity and specificity of the OligoC‐TesT and nucleic acid sequence‐based amplification coupled to oligochromatography (NASBA‐OC) for molecular detection of Leishmania in blood from patients with confirmed visceral leishmaniasis (VL) and healthy endemic controls from Kenya. Methods Blood specimens of 84 patients with confirmed VL and 98 endemic healthy controls from Baringo district in Kenya were submitted to both assays. Results The Leishmania OligoC‐TesT showed a sensitivity of 96.4% (95% confidence interval [CI]: 90–98.8%) and a specificity of 88.8% (95% CI: 81–93.6%), while the sensitivity and specificity of the NASBA‐OC were 79.8% (95% CI: 67–87%) and 100% (95% CI: 96.3–100%), respectively. Conclusion Our findings indicate high sensitivity of the Leishmania OligoC‐TesT on blood while the NASBA‐OC is a better marker for active disease.     

Effects of Azospirillum brasilense with genetically modified auxin biosynthesis gene ipdC upon the diversity of the indigenous microbiota of the wheat rhizosphere

The phytostimulatory properties of Azospirillum inoculants, which entail production of the phytohormone indole-3-acetic acid (IAA), can be enhanced by genetic means. However, it is not known whether this could affect their interactions with indigenous soil microbes. Here, wheat seeds were inoculated with the wild-type strain Azospirillum brasilense Sp245 or one of three genetically modified (GM) derivatives and grown for one month. The GM derivatives contained a plasmid vector harboring the indole-3-pyruvate/phenylpyruvate decarboxylase gene ipdC (IAA production) controlled either by the constitutive promoter PnptII or the root exudate-responsive promoter PsbpA, or by an empty vector (GM control). All inoculants displayed equal rhizosphere population densities. Only inoculation with either ipdC construct increased shoot biomass compared with the non-inoculated control. At one month after inoculation, automated ribosomal intergenic spacer analysis (ARISA) revealed that the effect of the PsbpA construct on bacterial community structure differed from that of the GM control, which was confirmed by 16S rDNA-based denaturing gradient gel electrophoresis (DGGE). The fungal community was sensitive to inoculation with the PsbpA construct and especially the GM control, based on ARISA data. Overall, fungal and bacterial communities displayed distinct responses to inoculation of GM A. brasilense phytostimulators, whose effects could differ from those of the wild-type.     

Neuroepidemiologic trends in 105 US cases of pediatric opsoclonus-myoclonus syndrome.

Opsoclonus-myoclonus syndrome (OMS) is a rare, autoimmune neurological disorder that is poorly recognized and undertreated. Neuroblastoma is found in one half of the cases. Because of the high incidence of spontaneous regression of neuroblastoma, it is unknown whether not finding a tumor means there was none. To define demographic trends and the standard of care in the first large series of OMS, 105 children were recruited over a 13-year period in a retrospective questionnaire survey. Children with and without a tumor differed little in viral-like prodrome and neurological symptoms. Earliest neurological symptoms were staggering and falling, leading to a misdiagnosis of acute cerebellitis. Later symptoms included body jerks, drooling, refusal to walk or sit, speech problems, decreased muscle tone, opsoclonus, and inability to sleep. Tumor resection alone did not provide adequate therapy for most. Adrenocorticotropic hormone (ACTH), prednisone, and intravenous immunoglobulin were used with equal frequency, but ACTH was associated with the best early response. More than one half of the children had relapses. Residual behavioral, language, and cognitive problems occurred in the majority. The delay in diagnosis (11 weeks) and initiation of treatment (17 weeks) is unacceptably long.