Global transcriptomic analysis in avocado nursery trees reveals differential gene expression during asymptomatic infection by avocado sunblotch viroid (ASBVd).

Avocado sunblotch viroid (ASBVd) is the type species of the family Avsunviroidae and the causal agent of avocado sunblotch disease. The disease is characterised by the presence of chlorotic lesions on avocado fruit, leaves and/or stems. Infected trees may remain without chlorosis for extended periods of time, though distorted growth and reduced yield has been observed in these cases. The molecular effects of ASBVd on avocado, and members of the Avsunviroidae on their respective hosts in general, remain poorly understood. Host global transcriptomic studies within the family Pospiviroidae have identified several host pathways that are affected during these plant-pathogen interactions. In this study, we used RNA sequencing to investigate host gene expression in asymptomatic avocado nursery trees infected with ASBVd. Transcriptome data showed that 631 genes were differentially expressed, 63 % of which were upregulated during infection. Plant defence responses, phytohormone networks, gene expression pathways, secondary metabolism, cellular transport as well as protein modification and degradation were all significantly affected by ASBVd infection. This work represents the first global gene expression study of ASBVd-infected avocado, and the transcriptional reprogramming observed during this asymptomatic infection improves our understanding of the molecular interactions underlying broader avsunviroid-host interactions.

Measurement of supersonic jet screech with focused laser differential interferometry.

Focused laser differential interferometry (FLDI) is used to measure a well-characterized, 17 kHz screech tone emitted from an underexpanded Mach 1.5 jet. Measurements are made at numerous spatial locations in and around the jet flow-field, where intrusive diagnostics would otherwise influence the flow-field. Results from FLDI measurements are shown to agree with measurements from microphones and analyses of high-speed schlieren. The agreement is used to demonstrate FLDI is a valid and accurate technique for measuring screech tones in jet flow-fields, and furthermore that FLDI can be used to measure jet screech at various spatial locations around the jet, and notably inside of the jet, where microphones and other intrusive diagnostics cannot be used effectively.

Diversity of Parasites from Xenopus Laevis (Amphibia: Pipidae) and their Seasonal Rate of Infection in Selected Habitats in the Limpopo Province, South Africa.

This study determined the diversity and seasonality of parasites species of the African clawed frog, Xenopus laevis (Daudin, 1802), from three localities, namely Modjadjikloof, Mokopane and University of Limpopo, Limpopo Province, South Africa. A total of seven parasite species were collected and identified. They included two nematodes, Camallanus kaapstaadi Southwell & Kirshner, 1937 and Batrachocamallanus slomei (Southwell & Kirshner, 1937), a monogenean, Protopolystoma xenopodis (Price, 1943), a cestode, Cephalochlamys namaquensis (Cohn, 1906), a protozoan, Trichodina xenopodos Fantham, 1924, two digeneans, Progonimodiscus doyeri Ortlepp, 1926 and Dollfuschella rodhaini Vercammen-Grandjean, 1960. The most common and abundant parasite species by far were Cm. kaapstaadi, B. slomei and Cp. namaquensis, with Cm. kaapstaadi, B. slomei present in all localities. Trichodina xenopodos was a rare species, only present in host populations from Modjadjiskloof. Modjadjiskloof had the highest species richness (all seven parasite species) followed by Mokopane (five parasite species) and University of Limpopo (3 parasite species). There were also higher infection levels (prevalence and mean intensity) of Cm. kaapstaadi, B. slomei, Cp. namaquensis and Pt. xenopodis in hosts from Modjadjiskloof while Pd. doyeri and D. rodhaini infection levels were greater in Mokopane. The variability between localities shows that parasites with heteroxenous life cycles are more strongly associated with more pristine habitats. The variability in calculated indices (prevalence and mean intensity) also suggests that the occurrence of some of the parasites is affected by season, favouring higher infection rates during summer. This suggests that temperature has a direct role in the reproductive and developmental processes of these parasites. Neither length nor sex had an influence on the prevalence or intensity of parasites.

Phentermine interference and high L-methamphetamine concentration problems in GC-EI-MS SIM Analyses of R-(-)-α-methoxy-α-(trifluoromethyl)phenylacetyl chloride-derivatized amphetamines and methamphetamines†.

In order to achieve chromatographic separation, urine samples shown to be initially positive for amphetamines and methamphetamines in US Department of Defense immunoassays are derivatized with R-(-)-α-methoxy-α-(trifluoromethyl)phenylacetyl chloride (R-(-)-MTPA) prior to gas chromatography-electron impact-mass spectrometry (GC-EI-MS) analysis. Phentermine, a member of the phenethylamine class of drugs and a common appetite suppressant, interferes with GC-EI-MS assays of R-(-)-MTPA-derivatized d-amphetamine, degrading the chromatography of the internal standard and analyte ions and skewing concentration calculations. Additionally, when specimens with high concentrations of l-methamphetamine are derivatized with R-(-)-MTPA, signal peaks have the potential to be misidentified by integration software as d-methamphetamine. We have found that replacing R-(-) MTPA with (S)-(+)-α-methoxy-α-(trifluoromethyl)phenylacetyl chloride reduces phentermine interference problems related to internal standard chromatography, reduces the possibility of concentrated l-methamphetamine peaks being misidentified by integration software, improves resolution of d-methamphetamine in the presence of high l-methamphetamine concentrations, and is a cost-neutral change that can be applied to current amphetamines GC-EI-MS methods without the need for method modification.

Predicting antigenic sites on the foot-and-mouth disease virus capsid of the South African Territories types using virus neutralization data.

Foot-and-mouth disease virus (FMDV) outer capsid proteins 1B, 1C and 1D contribute to the virus serotype distribution and antigenic variants that exist within each of the seven serotypes. This study presents phylogenetic, genetic and antigenic analyses of South African Territories (SAT) serotypes prevalent in sub-Saharan Africa. Here, we show that the high levels of genetic diversity in the P1-coding region within the SAT serotypes are reflected in the antigenic properties of these viruses and therefore have implications for the selection of vaccine strains that would provide the best vaccine match against emerging viruses. Interestingly, although SAT1 and SAT2 viruses displayed similar genetic variation within each serotype (32 % variable amino acids), antigenic disparity, as measured by r(1)-values, was less pronounced for SAT1 viruses compared with SAT2 viruses within our dataset, emphasizing the high antigenic variation within the SAT2 serotype. Furthermore, we combined amino acid variation and the r(1)-values with crystallographic structural data and were able to predict areas on the surface of the FMD virion as antigenically relevant. These sites were mostly consistent with antigenic sites previously determined for types A, O and C using mAbs and escape mutant studies. Our methodology offers a quick alternative to determine antigenic relevant sites for FMDV field strains.

Direct percutaneous venous puncture and embolization of giant perimedullary arteriovenous fistulas.

PMAVFs are rare entities that are formed by a direct communication between an artery that feeds the spinal cord and a vein. The goal of treatment is to occlude the shunt; this is done endovascularly either from an arterial or a venous approach. When these approaches are not possible, direct percutaneous puncture of the draining veins may be attempted to embolize the arteriovenous shunt directly.

Five-Year Longitudinal MRI Follow-up and (1)H Single Voxel MRS in 14 patients with Gliomatosis Treated with Temodal, Radiotherapy and Antiangiogenic Therapy.

Gliomatosis cerebri (GC) is a challenging tumor, considered to have a poor prognosis and poor response to treatments. The purpose of this study is to better understand glial tumor metabolism and post chemotherapy, radiotherapy and antiangiogenic variations in a longitudinal study to determine cerebral variation in MRS area, amplitude, and ratios of metabolites and spectral profiles during a five year longitudinal follow-up in 14 patients with gliomatosis without initial hyperperfusion and treated with chemotherapy (Temozolomide (Temodal(®))), radiotherapy and subsequent antiangiogenic therapy. The study also aimed to detect changes in infiltration, proliferation, lipids or glycolytic metabolism, as these changes could be monitored longitudinally in humans with glial brain tumors (low and high grade) after therapy, using conventional magnetic resonance imaging (MRI), spectroscopy (MRS) and MR perfusion. Most patients had first initial clinical and MRS improvement and stable MRI. After 12 to 24 chemotherapy treatment cycles MRS usually showed an increase in the Cho/Cr ratio (proliferation) and sometimes contrast enhancements. Later, the patients showed clinical deterioration and radiotherapy was started. There was an improvement with radiotherapy that lasted nine to 18 months. This was followed by a worsening that led to try antiangiogenic therapy. Later in the evolution for three patients with hyperperfusion this symptom disappeared, but proliferation, infiltration and glycolytic metabolism remained at a high level. Spectroscopic and metabolic changes often occur well before clinical deterioration and sometimes before improvement. Therefore, MRS could be more sensitive and could detect changes earlier than MRI and is sometimes predictive. Despite the difficulty, the variability and unknown factors, these repeated measurements give us a better insight into the nature of the different processes, tumor progression and could lead to better understanding of therapeutic response.

Percutaneous treatment of cervical disk hernias using gelified ethanol.

This study investigates the efficacy of chemonucleolysis using RGE in the treatment of cervical disk hernias in a small sample of patients who had cervical diskogenic or radicular pain secondary to disk herniations. Results were satisfactory in 89.5% patients, with no adverse events recorded during the procedure or after. The use of RGE shows promising results and might be a feasible and safe alternative in the treatment of cervical disk hernias.

Modification, crosslinking and reactive electrospinning of a thermoplastic medical polyurethane for vascular graft applications.

Thermoplastic polyurethanes are used in a variety of medical devices and experimental tissue engineering scaffolds. Despite advances in polymer composition to improve their stability, the correct balance between chemical and mechanical properties is not always achieved. A model compound (MC) simulating the structure of a widely used medical polyurethane (Pellethane) was synthesized and reacted with aliphatic and olefinic acyl chlorides to study the reaction site and conditions. After adopting the conditions to the olefinic modification of Pellethane, processing into flat sheets, and crosslinking by thermal initiation or ultraviolet radiation, mechanical properties were determined. The modified polyurethane was additionally electrospun under ultraviolet light to produce a crosslinked tubular vascular graft prototype. Model compound studies showed reaction at the carbamide nitrogen, and the modification of Pellethane with pentenoyl chloride could be accurately controlled to up to 20% (correlation: rho=0.99). Successful crosslinking was confirmed by insolubility of the materials. Initiator concentrations were optimized and the crosslink densities shown to increase with increasing modification. Crosslinking of Pellethane containing an increasing number of pentenoyl groups resulted in decreases (up to 42%, p<0.01) in the hysteresis and 44% in creep (p<0.05), and in a significant improvement in degradation resistance in vitro. Modified Pellethane was successfully electrospun into tubular grafts and crosslinked using UV irradiation during and after spinning to render them insoluble. Prototype grafts had sufficient burst pressure (>550 mm Hg), and compliances of 12.1+/-0.8 and 6.2+/-0.3%/100 mm Hg for uncrosslinked and crosslinked samples, respectively. It is concluded that the viscoelastic properties of a standard thermoplastic polyurethane can be improved by modification and subsequent crosslinking, and that the modified material may be electrospun and initiated to yield crosslinked scaffolds. Such materials hold promise for the production of vascular and other porous scaffolds, where decreased hysteresis and creep may be required to prevent aneurismal dilation.

Late presentation of aorto-right ventricular fistula and associated aortic regurgitation following penetrating chest trauma.

We present a case in which a 39-year-old man was assaulted in 2002 and sustained penetrating chest trauma. He was treated conservatively, and presented six years later with exertional dyspnoea and a continuous murmur. Echocardiography detected an aorta-right ventricular fistula and an important aortic regurgitation. The aorta-right ventricular fistula was repaired and the aortic valve was replaced with a mechanical prosthesis. Traumatic aorto-right ventricular fistulas and aortic regurgitation are often masked by the primary injury and may take months or years to become clinically evident.

Study on the efficacy and safety of different antigens and oil formulations of infectious coryza vaccines containing an NAD-independent strain of Avibacterium paragallinarum.

The present study was designed to assess and compare three different formulations of the new Onderstepoort infectious coryza (IC) quadrivalent vaccine, which contain an NAD-independent strain of Avibacterium paragallinarum (previously known as Haemophilus paragallinarum), and a commercial IC vaccine, not containing an NAD-independent strain, for their safety and ability to protect chickens of varying ages against virulent challenges with four different serovars of A. paragallinarum, including the NAD-independent strain of the C-3 serovar. Four groups of 140 chickens each were vaccinated at the age of 17 weeks and revaccinated at the age of 19 weeks with each of the four vaccine formulations. A similar sized group of non-vaccinated chickens was used as control. Two rounds of challenge were conducted: a group of chicken in each vaccination group was challenged between 31 and 35 weeks of age, while another group was challenged between 51 and 55 weeks of age. The "in-contact" challenge model was used in this experiment. For each vaccination group, the four challenge strains representing four local serovars were used in each challenge round. The efficacy of the vaccines was compared based on overall protection levels obtained and the duration of protection. The safety of the different vaccines was determined by the severity of post-vaccination reactions. The need for the incorporation of the NAD-independent strain in the vaccine was evidenced by the low protection level against NAD-independent challenge recorded in the group of birds vaccinated with the commercial vaccine. The results obtained confirmed not only the variation in virulence of different South African serovars, with serovar C-3 being the most virulent and serovar B having almost no virulence but also the age related increase in susceptibility. The importance of a suitable formulation of the vaccine is discussed.

Low density contrast agents for x-ray phase contrast imaging: the use of ambient air for x-ray angiography of excised murine liver tissue.

We report a new preparative method for providing contrast through reduction in electron density that is uniquely suited for propagation-based differential x-ray phase contrast imaging. The method, which results in an air or fluid filled vasculature, makes possible visualization of the smallest microvessels, roughly down to 15 microm, in an excised murine liver, while preserving the tissue for subsequent histological workup. We show the utility of spatial frequency filtering for increasing the visibility of minute features characteristic of phase contrast imaging, and the capability of tomographic reconstruction to reveal microvessel structure and three-dimensional visualization of the sample. The effect of water evaporation from livers during x-ray imaging on the visibility of blood vessels is delineated. The deformed vascular tree in a cancerous murine liver is imaged.

Nanotechnology and water treatment: applications and emerging opportunities.

Nanotechnology, the engineering and art of manipulating matter at the nanoscale (1-100 nm), offers the potential of novel nanomaterials for treatment of surface water, groundwater, and wastewater contaminated by toxic metal ions, organic and inorganic solutes, and microorganisms. Due to their unique activity toward recalcitrant contaminants and application flexibility, many nanomaterials are under active research and development. Accordingly, literature about current research on different nanomaterials (nanostructured catalytic membranes, nanosorbents, nanocatalysts, and bioactive nanoparticles) and their application in water treatment, purification and disinfection is reviewed in this article. Moreover, knowledge regarding toxicological effects of engineered nanomaterials on humans and the environment is presented.

Cloning and characterization of a 4-hydroxyphenylacetate 3-hydroxylase from the thermophile Geobacillus sp. PA-9.

A 4-hydroxyphenylacetic acid (4-HPA) hydroxylase-encoding gene, on a 2.7-kb genomic DNA fragment, was cloned from the thermophile Geobacillus sp. PA-9. The Geobacillus sp. PA-9 4-HPA hydroxylase gene, designated hpaH, encodes a protein of 494 amino acids with a predicted molecular mass of 56.269 Da. The deduced amino-acid sequence of the hpaH gene product displayed <30% amino-acid sequence identity with the larger monooxygenase components of the previously characterized two-component 4-HPA 3-hydroxylases from Escherichia coli W and Klebsiella pneumoniae M5a1. A second oxidoreductase component was not present on the 2.7-kb genomic DNA fragment. The deduced amino-acid sequence of a second C-terminal truncated open reading frame, designated hpaI, exhibited homology to extradiol oxygenases and displayed the highest amino-acid sequence identity (43%) with the 3,4-dihydroxyphenylacetate 2,3-dioxygenase of Arthrobacter globiformis, encoded by mndD. These results, along with catalytic activity observed in crude intracellular extracts prepared from Escherichia coli cells expressing hpaH, is in support of a role for hpaH in the 4-HPA degradative pathway of Geobacillus sp. PA-9.

X-ray phase-contrast imaging: transmission functions separable in Cartesian coordinates.

In-line, x-ray phase-contrast imaging is responsive to both phase changes and absorption as the x radiation traverses a body. Expressions are derived for phase-contrast imaging of objects having transmission functions separable in Cartesian coordinates. Starting from the Fresnel-Kirchhoff integral formula for image formation, an expression is found for the phase-contrast image produced by an x-ray source with nonvanishing dimensions. This expression is evaluated in limiting cases where the source-to-object distance is large, where the source acts as a point source, and where the weak phase approximation is valid. The integral expression for the image is evaluated for objects with simple geometrical shapes, showing the influence of the source dimensions on the visibility of phase-contrast features. The expressions derived here are evaluated for cases where the magnification is substantially greater than one as would be employed in biological imaging. Experiments are reported using the in-line phase-contrast imaging method with a microfocus x-ray source and a CCD camera.

A second RGD motif in the 1D capsid protein of a SAT1 type foot-and-mouth disease virus field isolate is not essential for attachment to target cells.

The amino acid sequence motif Arg-Gly-Asp (RGD), located in the surface-exposed betaG-betaH loop of the 1D protein of different serotypes and subtypes of foot-and-mouth disease virus (FMDV), is highly conserved and participates in binding of FMDV to susceptible cells. Previous sequence analyses of the 1D-encoding region of a FMDV serotype SAT1 field isolate from Namibia (NAM/307/98) indicated the presence of a second RGD motif upstream of the conserved betaG-betaH loop RGD. The role of these RGD sequences in virus infection was investigated by mutating the betaG-betaH loop RGD to a KGE tripeptide, using a genome-length infectious chimeric cDNA clone. Although the infectivity of the derived mutant viruses for baby hamster kidney cells (BHK-21) was lost, subsequent replacement of the KGE sequence with RGD in the mutant cDNA clone led to recovery of infectious viruses. Furthermore, viral RNA replication could be demonstrated with the genetically engineered mutant and non-mutant viruses. The presence of virus particles in the transfected cells could be also demonstrated by electron microscopy. These results demonstrate that, in contrast to the betaG-betaH loop RGD motif, the second RGD sequence in the capsid protein 1D of NAM/307/98 does not function as a ligand for receptor binding in BHK-21 cells.

Ultrasound-assisted transthoracic biopsy: fine-needle aspiration or cutting-needle biopsy?

The present study compared the diagnostic yield of ultrasound-assisted cutting-needle biopsy (CNB) and fine-needle aspiration biopsy (FNAB) in chest lesions. A physician performed ultrasound and FNAB with a 22-G spinal needle in all patients, directly followed by a 14-G CNB in patients without contraindication. A total of 155 consecutive lesions arising from the lung (74%), pleura (12%), mediastinum (11%) or chest wall (3%) in patients with a final diagnosis of lung carcinoma (74%), other malignant tumours (12%), non-neoplastic disease (9%) or unknown (5%) were prospectively included. The overall diagnostic yield was 87%. Combined specimens were obtained in 123 lesions (79%). In these, yields of FNAB, CNB and both methods combined were 82, 76 and 89%, respectively. FNAB was significantly better than CNB in lung carcinoma (95 versus 81%) but CNB was superior in noncarcinomatous tumours and in benign lesions. On-site cytology was 90% sensitive and 100% specific for predicting a positive FNAB. One patient required drainage for pneumothorax (0.6%). Ultrasound-assisted fine-needle aspiration biopsy performed by chest physicians is an accurate and safe initial diagnostic procedure in patients with a high clinical probability of lung carcinoma. All other patients should undergo concurrent fine-needle aspiration biopsy and cutting-needle biopsy.

Transbronchial needle aspirates: how many passes per target site?

Transbronchial needle aspiration is a bronchoscopic sampling method for a variety of bronchial and pulmonary lesions. The present study investigated whether and how serial needle passes contribute to the yield of transbronchial needle aspiration at specific target sites. A total of 1,562 needle passes, performed at 374 target sites in 245 patients with neoplastic disease (82%), non-neoplastic disease (15%) or undiagnosed lesions (3%), were prospectively recorded and rated for anatomical location, size, bronchoscopic appearance and underlying disease. Positive aspirates were obtained in 75% of patients and at 68% of target sites. A diagnosis was established with the first, second, third and fourth needle pass at 64, 87, 95 and 98% of targets, respectively. The absolute yield varied strongly with target site features, but the stepwise increment to the maximum yield provided by serial passes was similar across target sites. In conclusion, three transbronchial needle passes per site are appropriate when only a tissue diagnosis is sought and when alternative sites or sampling modalities are available. At least four or five passes should be carried out at lymph node stations critical for the staging of lung cancer.

Radial approach in the treatment of supraaortic arterial lesions.

SUMMARY: Radial approach (mainly right) has been used in the treatment of 67 supraaortic lesions including 56 carotid, nine vertebral and two subclavian artery stenoses. This approach offers new possibilities and solves most of the remaining technical difficulties or impossibilities encountered in the endovascular treatment of supraaortic lesions. The current technique is described. The results of this first series have been very satisfactory without complication. MR angiography allows selection of patients suitable for radial approach.